PI/Investigator: Benoit D'Autréaux, PhD, Mixed Research Unit (UMR 9198), Centre National de la Recherche Scientifique (CNRS), Commissariat à l'Energie Atomique et aux énergies alternatives (CEA), Paris-Saclay University

Award type: General Research Grant

Grant Title: Cell-free high throughput screening assays for the discovery of compounds replacing frataxin in FA

Lay summary: Friedreich's ataxia (FA) is a neurodegenerative and cardiac disease caused by genetic mutations in the gene encoding the protein frataxin (FXN). FXN is an important protein in the synthesis of cofactors of enzymes called iron-sulfur clusters, which are involved in a multitude of essential biological functions such as energy production and defense against oxidative stress. Although promising gene therapy and pharmacologic approaches are currently under development for FA, there is still no treatment to cure or even slow disease progression.

A novel strategy to develop FA therapeutics would be to either replace FXN function or enhance the activity of residual FXN in FA patients. This group has developed a biochemical assay that can measure the results of FXN activity by faithfully reproducing the physiological conditions of Fe-S cluster biosynthesis using a reconstituted machinery with isolated proteins. They found that FXN stimulates Fe-S cluster biosynthesis by enhancing the mobilization of sulfur. Their goal is to use this reconstituted system to develop a cell-free high throughput assay to randomly screen large chemical libraries (in the range of 100,000 compounds) and identify molecules that could produce the same effect as FXN does on Fe-S cluster synthesis formation. They will also test candidate molecules: sulfur donors and molecules that were previously identified by their ability to mitigate the cardiac phenotype of FA. The molecules selected in these assays will then be evaluated in vivo, using a new fly model of FA. The advantage of this animal model is that it allows rapid evaluation of drug candidates, which will facilitate future drug-design procedures to improve the efficiency of the molecules selected in the screens.

This novel high throughput cell-free assay will allow the researchers to select a large number of molecules directly targeting the primary defect in FA that could lead to the discovery of the first drugs specifically active in the replacement of FXN, which would result in a new class of potential FA therapeutics.

PI/Investigator: Joseph Nabhan, PhD – Vesigen Therapeutics, Cambridge (MA)

Award type: General Research Grant

Grant Title: Evaluation of ARMMs-mediated delivery of Cas9 protein complexed with gRNAs as a non-viral disease-modifying strategy for Friedreich’s ataxia

Lay summary: Excision of the pathogenic GAA repeat expansion from at least one of the FXN alleles has the potential to be a transformative therapy for FA patients, as it does not carry the same potential for toxicity as gene therapy approaches delivering high levels of frataxin using Adeno-Associated Virus (AAV). Unfortunately, despite significant advances in gene editing technologies, like the ones using the CRISPR-Cas9 system, there are limited options for safe, transient, and targeted delivery to disease-affected cell types of these gene editing tools. ARRDC1-Mediated Microvesicles (ARMMs) are a distinct class of extracellular vesicles derived from the cell membrane that are produced through the activity of the protein ARRDC1. Vesigen Therapeutics has developed approaches to engineer their ARMMs to load a variety of cargos, including the tools necessary for genome editing of the GAA repeats. Payloads such as the gene editor Cas9 can be attached to ARRDC1, which actively recruits the cargo into engineered ARMMs. This proposal sets out to evaluate the use of ARMMs as a non-viral delivery vehicle for genome editing tools to excise the pathogenic repeat expansion in FXN. One challenge in this work will be successfully engineering ARMMs to target the tissues most affected in FA, specifically the proprioceptive system, which is responsible for the ability to sense body position and movement and whose early loss in FA leads to limited ambulatory capacity in patients.

PI/Investigator: Changfan Lin, PhD - Caltech

Award type: Postdoctoral Fellowship

Grant Title: Engineering adeno-associated viral vectors to evade immune responses

Lay summary: Gene therapy works by transferring genetic materials (cargo, the FXN gene) in a vector to FA-damaged tissues. Adeno-associated virus vectors (AAVs) are the leading vectors used in gene therapy, given their safe clinical record, robust delivery efficiency, specificity, and superior ability to enter the brain. There are also extensive studies to package regulatory elements into AAVs to make the cargo gene only active in FA-affected tissues, thus minimizing unnecessary harm to other tissues. There are two typical ways to deliver AAVs to human bodies: direct injection and intravenous (IV) injection. Direct injection involves delivering the AAVs directly into the target organ, but its downside is that it will not treat all affected tissues. IV injection on the other hand allows the AAVs to circulate in the bloodstream and reach all therapeutic targets throughout the body. However, IV injections bring the risk of immune toxicity. Up to 70% of human populations have neutralizing antibodies (NAbs) against AAVs which trigger severe immune responses and body damage. For this reason, many clinical treatments have opted to exclude patients with NAbs from AAV-based gene therapy. This proposal aims to engineer AAVs to escape from these Nabs, enabling the treatment of all FA patients. Dr. Lin aims to: (1) develop NAb-based selection assays and screen AAV variants to discover new AAVs that don't bind to NAbs and retain the desired delivery function in model animals; (2) develop novel AAVs targeting newly identified receptors important for AAVs to enter the human brain, in order to enhance brain delivery.

PI/Investigator: Arturo Sala, PhD - Brunel University, London

Award type: Kyle Bryant Translational Research Award

Grant Title: Therapeutic activity of a haematopoietic stem cell delivered tissue penetrating peptide in a Friedreich's ataxia mouse model

Lay summary: The idea behind this proposal is to restore the expression of the Frataxin protein in Friedreich's patients by engineering a secreted, cell penetrating version of the molecule that will be delivered by haematopoietic stem cells (HSCs). Patient's blood stem cells will be modified to carry a virus that produces the cell-penetrating Frataxin. The Frataxin-producing stem cells will be reinfused into patients where they will be retained into the bone marrow. Modified haematopoietic cells circulating in the blood stream will differentiate into macrophages, oligodendrocytes and other terminally differentiated cells which will deliver the therapeutic protein to the damaged tissues, hopefully resulting in a permanent treatment. The main goal of the study is to validate this concept using a mouse model of Friedrich's ataxia, called YG8XLR. YG8XLR mice show reduced expression of FXN and symptoms similar to those of patients. Dr. Sala and his collaborators will use this mouse model to investigate whether intravenous injections of HSCs modified to express Frataxin fused to a cell penetrating peptide ameliorate symptoms and restore normal organ systems functions. In parallel, they will carry out safety studies to gain proof of principle that expression of the therapeutic gene and lentivirus infections are well tolerated and do not result in genotoxicity in mice. If completed, this study should lead to the first cell and gene therapy trial for Friedrich's ataxia.

PI/Investigator: Stephanie Cherqui, PhD - University of California, San Diego

Award type: General research grant

Grant Title: Mechanism of neuronal rescue by microglia expressing frataxin and characterization of neuronal defects in Friedreich's ataxia

Lay summary: Dr. Cherqui and her group showed that, in a mouse model of FRDA, bone marrow stem cells, especially the hematopoietic stem cells (HSCs) that give rise to blood cells, hold great promise to treat FRDA. Indeed, transplantation of healthy HSCs led to the prevention of the neurological, and muscular complications in the mouse model. The mechanism by which frataxin-expressing HSCs protected the tissues is mediated by the differentiation of the transplanted HSCs into microglia/macrophages (type of immune cells) within tissues, that will transfer the functional frataxin to the brain cells (neurons) and muscle and heart cells (cardiomyocytes and myocytes). The exact mechanism of frataxin transfer is still unknown and determining the mechanism of action is crucial for designing adequate safety and efficacy studies to meet FDA requirements for future clinical application of HSC transplantation for FRDA. Because these questions cannot be answered in vivo, this group will utilize induced pluripotent stem cells (iPSCs) derived from FRDA patients and healthy donor fibroblasts to generate microglia, neurons, and cerebral organoids (mini-brains) to study the microglial-neuronal interaction and, potentially, the mitochondria transfer. We will also utilize these new models of FRDA to investigate the pathogenesis of the neurodegeneration in this disease, and the potential impact of the frataxin-deficient microglia in this degenerative process. Indeed, using their 2D and 3D FA models, they already observed significant phenotype in the FA-neurons and FA-microglia compared to controls. This work will lead to a better understanding of the mechanism by which HSC transplantation leads to improvement of the neurological symptoms, will further the understanding of FRDA neuropathogenesis, and potentially identify new therapeutic targets to prevent or slow neuronal death in FRDA patients.

Co-sponsor: fara Australia

PI/Investigator: Hélène Puccio, PhD - Institute NeuroMyoGène, Lyon, France

Award type: General Research Grant

Grant Title: Defining the therapeutic window and threshold for neuronal gene therapy in Friedreich Ataxia

Lay summary: Gene replacement therapy is an experimental technique that uses genetic material to treat or prevent a disease. One promising gene replacement therapeutic approach for Friedreich ataxia (FA) is to deliver the frataxin gene to affected cells, using viral vectors. Several groups have recently shown that this type of approach could prevent and treat the disease in relevant mouse models. However, there are a number of questions that need to be addressed to optimize the development of a safe therapeutic protocol. In particular, it is now accepted in the field that too much frataxin expression can be detrimental to the normal function of the cell. It is therefore essential to develop a therapeutic vector that will mimic the normal endogenous expression of frataxin. Furthermore, it is important to estimate the number of neurons that need to be corrected to produce a clinical benefit. Recent studies have shown that the sensory ataxia in FA might be partly related to problems during the development, and it is therefore important to determine if gene replacement can correct this very early damage to the tissue. Dr. Puccio and her team will address these questions with a particular focus on the neurological aspects, using two relevant mouse models of the disease, and a novel viral vector that expresses frataxin at near physiological levels.

PI/Investigator: Jill Napierala, PhD - University of Alabama at Birmingham

Award type: General Research Grant

Grant Title: Regulation of frataxin expression - implications for Friedreich's ataxia therapy

Lay summary: Friedreich's ataxia (FRDA), a severe progressive neurodegenerative disorder, is caused by an increasing number of specific DNA sequences, termed GAA repeats, that are present in the Friedreich's ataxia gene (FXN). This error in DNA causes a block in the flow of information from DNA to RNA, and ultimately leads to a deficiency of the final FXN product, a protein called frataxin. One of the major types of therapeutic approaches for FRDA currently being developed tries to counteract this frataxin deficiency. In order for the therapy to be successful, we need to determine what is the minimum amount of frataxin increase that will be beneficial for patients as well as what is the maximum possible increase of frataxin that will not cause any negative consequences. This is called a therapeutic window and is an essential parameter for therapy development for FRDA. Also, to better understand dosing of potential drugs that could increase frataxin levels, results of the proposed work will determine the ways that frataxin production, maintenance and removal are controlled. In summary, this work is contributing to the development of critical therapeutic guidelines for treatment of frataxin deficiency in Friedreich's ataxia.

PI/Investigator: Natalia Gomez-Ospina, MD, PhD - Stanford University

Award type: General Research Grant

Grant Title: Development of autologous transplantation of genetically corrected hematopoietic stem cells for Friedreich Ataxia

Lay summary: Previous studies have suggested that bone marrow transplantation can improve symptoms in a mouse model of Friedreich's ataxia. A conclusive demonstration of the efficacy and feasibility of such an approach for this disease would enable a one-time treatment for this otherwise devastating disease. If such benefit were to be firmly established, as it has in other neurological diseases, donor-blood stem cell transplantation could quickly become a treatment alternative for individuals with Friedreich's ataxia, while launching the development of patient-derived stem cell transplantation approaches in which the patient's own stem cells have been genetically corrected. Dr. Gomez-Ospina proposes to investigate the application of blood stem cell transplantation to treat Friedreich's ataxia by: 1) performing stem cell transplantation experiments into a new model of Friedreich's ataxia and assessing the molecular and functional outcomes, 2) using genetic engineering to investigate whether expression of the protein Frataxin is required in specific blood cell types for the therapeutic benefit of stem cell transplant, and 3) establishing an in vitro model to assess if cellular bodies called mitochondria undergo inter-cellular transfer to confer function to neighboring cells. These studies will provide support for further development of a blood stem cell-based therapy for Friedreich's ataxia.
Co-funding: FARA Ireland

PI/Investigator: Daniele Lettieri-Barbato, PhD - University of Rome Tor Vergata, Italy

Award type: General Research Grant

Grant Title: Testing the efficacy of dietary butyrate in ameliorating ataxic symptoms in Friedreich's ataxia mouse models

Lay summary: Together with degeneration in the brain and spinal cord, FRDA patients frequently develop metabolic complications that culminate in heart disease and type 2 diabetes, which significantly aggravate FRDA progression. A direct link has been discovered in recent years between the gut and the brain and alteration of the composition of the microbial gut population is associated with several neurodegenerative diseases. In this project, by using mouse models of FRDA, Dr. Lettieri-Barbato and his team will investigate whether the gut microbiome is altered in FRDA with a particular focus on bacteria producing short chain fatty acids, including butyrate, as these molecules possess both a neuroprotective and anti-diabetic function. FRDA mice will be treated with a diet rich in butyrate and the effect on motor function and molecular hallmarks of the disease will be analyzed in the cerebellum at single cell level. If butyrate will demonstrate efficacy in mitigating the neuromotor symptoms and molecular deregulation identified in the cerebellum of FRDA mouse models, translation from bench to bedside could be highly feasible as this physiologically produced molecule has been shown to be safe in humans.

Co-sponsor: AFAF

PI/Investigator: Elena Dedkova, PhD - University of California, Davis

Award type: General Research Grant

Grant Title: Cardiac benefit of drugs that stimulate Nrf2 and HCA2 pathways in Friedreich's ataxia

Lay summary: The most common cause of death in Friedriech's ataxia (FA) is cardiomyopathy, thus a therapeutic drug that increases frataxin, iron-sulfur and mitochondrial functions has the potential to ameliorate the most lethal consequence of FA. Ixchel Pharma, a UC Davis spinout company, has developed a novel chemical entity, IMF, that increases frataxin, iron-sulfur and mitochondrial functions in the FXNKD mouse model of FA, that closely resembles the human FA condition. IMF dosing in these FXNKD mice rescues their cardiac pathology. Furthermore, IMF dosing increases survival in the frataxin MCK-Cre mouse, which only lacks frataxin in the heart, and dies because of this loss. Thus, IMF is potentially a novel therapeutic with greater efficacy than the related DMF, and operating through other mechanisms. This group proposes that IMF works by increasing frataxin expression and mitochondrial gene expression, which appears to be upstream from the target of RTA408, Omaveloxolone, which does not increase frataxin and works to benefit oxidative status downstream of frataxin deficiency. Thus, this group proposes to compare efficacy of IMF and RTA408 in mice, and if IMF has higher efficacy, then to carry out pharmacokinetics, metabolism and toxicity studies of IMF. If successful this would take IMF to the next level of preclinical development.

PI/Investigator: Pei-Yu Chen, PhD - Yale University

Award type: Award for Innovative Mindset

Grant Title: TGFβ signaling activity as disease biomarkers and therapeutic targets in Friedreich’s Ataxia

Lay summary: Friedreich’s ataxia (FA) is associated with fibrosis in the heart, a process by which the heart becomes thicker and stiffer and has a harder time pumping blood. Recently, the development of cardiac fibrosis has been linked to changes in the cells that make up the inner surface of blood vessels, called endothelial cells (ECs). The process involving these changes is called endothelial to mesenchymal transition or EndMT, and is a poorly understood phenomenon in which ECs become different cells. These cellular changes have been observed in heart samples obtained from FA patients, suggesting that EndMT in blood vessels may contribute to the pathogenesis of cardiac fibrosis in FA. Dr. Chen plans to study the molecular processes that characterize EndMT and its contribution to cardiac fibrosis in FA. The aims of these studies are to determine whether these molecular changes can be used to track the heart disease in FA and whether therapeutic interventions that disrupt this process could be beneficial.

PI/Investigator: Sarah Robinson-Thiewes, PhD - St. Jude Children’s Research Hospital

Award type: Postdoctoral Fellowship

Grant Title: Illuminating how SynGRs liberate gene expression from heterochromatin

Lay summary: The Ansari lab developed a new class of small molecule therapeutics called synthetic gene regulators (SynGRs), one of which, SynTEF1, binds to the FA GAA genetic mutation and specifically increases FXN expression. While the lab has a working model for how SynTEF1 works, the data also indicate that SynTEF1 pushes the boundaries of our knowledge of gene expression. Namely, that SynTEF1 improves FXN expression while the gene is considered “off”. Dr Robinson-Thiewes’s proposal is tailored to investigate the scientific quandaries SynTEF1 has illuminated and lay the groundwork to show that SyTEF1 is a viable treatment option for patients. To this end, this investigator has divided her proposal into three questions. First, how does SynTEF1 alleviate FXN's transcriptional dysregulation? To answer this question, Dr Robinson-Thiewes will use CRISPR/Cas9 genome editing to visualize FXN expression and predicted SynTEF1 protein partners in live cells. Second, does SynTEF1 restore mitochondrial function? To answer this question, she will treat FA patient cells with SynTEF1 and analyze mitochondrial health as well as markers of cellular damage. Third, how does long term exposure to SynTEF1 affect gene expression? To answer this question, she will use two complementary approaches to assess gene expression: RNA sequencing and sequencing that identifies area of the genome that could be “on”. Answering these questions will advance basic science investigations into gene expression that will be beneficial to not only FA patients, but to countless others who have diseases caused by faulty gene expression.

PI/Investigator: Anna Stepanova, PhD - Weill Cornell Medical College

Award type: Postdoctoral Research Award

Grant Title: Calcium communication among intracellular compartments in FA patient-derived cells

Lay summary: Cells interact with each other and within themselves using small molecules - words of the language of life. Calcium (Ca) is the most common means of communication within the cell, between its different compartments such as cytosol, mitochondria and endoplasmic reticulum (ER) - the main Ca storage inside the cell. Healthy cells keep cytosolic Ca levels at four orders of magnitude lower than extracellular ones. Ca is vital for the heart cells' well-being; however, keeping appropriate Ca levels requires a lot of energy, thus the good quality of mitochondria. This study aims to uncover the elusive link between mitochondria, Ca communication, and heart cells' well-being in patients with FA. Dr Stepanova and her collaborators will use a state-of-the-art technique to monitor Ca levels in specific locations inside the cell (cytosol, mitochondria, or ER). They will convert stem cells from FA patients into two heart cell types. 1) Cardiac muscle cells, or cardiomyocytes, are the most abundant cell type in the heart and are responsible for heart contraction. Each heartbeat relies on quick changes in Ca levels. 2) Myofibroblasts (MyoFB) are minor cell type in healthy hearts. However, they increase in number after an injury because of their role in wound healing. The overabundance of MyoFB can lead to cardiac fibrosis - a common heart condition found in FA. Ca plays a crucial role in various functions of MyoFB, and the knowledge of these cells in FA is limited. This study will answer whether heart cells suffer from miscommunication of Ca messages between different cell compartments and may lead to novel therapies for cardiomyopathy in FA.

PI/Investigator: Shawn Liu, PhD - Columbia University & Joriene de Nooij, PhD - Columbia University

Award type: General Research Grant

Grant Title: Rescue of Friedreich’s Ataxia cells by DNA methylation editing of the FXN gene

Lay summary: Reactivation of the silenced FXN gene represents an attractive therapeutic strategy because the FXN coding sequence remains intact in the vast majority of FRDA patients. However, the molecular mechanisms underlying the silencing of FXN are under active investigation. One of these mechanisms is DNA hypermethylation, a code that is written onto genes, but goes beyond the genetic code - thereby called epigenetic - and consist of chemically changing the structure of one of the 4 DNA building blocks, by adding methyl groups. DNA hypermethylation of the FXN gene has been documented in FRDA patients and has been correlated with FXN transcriptional deficiency and age of disease onset. However, the functional significance of this DNA methylation event to the pathogenesis of FRDA remains unclear due to the lack of a precise molecular tool to manipulate this methylation event in the disease-affected cells. Dr. Liu has developed a CRISPR-based molecular tool to precisely edit DNA methylation. With this new tool, his group will test whether demethylation of the FXN gene may reactivate its expression and rescue FRDA-associated cellular defects. In collaboration with Dr. Joriene De Nooij’s laboratory (co-principal investigator) at Columbia University Medical Center, Dr. Liu will apply the DNA methylation editing tool to demethylate FXN in sensory neurons derived from FRDA-patient induced pluripotent stem cells (iPSCs), and in Dorsal Root Ganglia sensory neurons obtained from a mouse model of FRDA. They will then phenotypically characterize the in vitro and in vivo DNA methylation-edited neurons. Precise editing of FXN methylation will permit an evaluation of the functional significance of this epigenetic event in the pathogenesis of FRDA. Moreover, these studies may demonstrate the therapeutic potential of DNA methylation editing for FRDA.

PI/Investigator: Xinnan Wang, MD, PhD - Stanford University

Award type: General Research Grant

Grant Title: Novel Mitochondrial Targets for Friedreich’s Ataxia

Lay summary: In this grant proposal, Dr. Wang seeks to target the oxidative stress in FA cells in a new way. ROS - reactive oxygen species - are highly reactive molecules normally produced in the cells by many reactions, but when allowed to accumulate, as is the case for FA, they can induce damage and eventually cell death. Dr. Wang proposes a new therapeutic strategy for FA that instead of reducing ROS, targets the consequences of elevated ROS inside the cell, that cause cell damage. Dr. Wang and her group discovered that high ROS levels cause impairment of a mechanism that is important to recycle mitochondria and found molecules that can target this mechanism and restore mitochondrial recycling. Dr. Wang provided evidence that targeting this pathway rescues the phenotype of a fruit fly model of FA and improves survival of FA cells. With this work she aims to validate novel therapeutic targets and test small molecules that could be translated into disease-modifying therapies.

PI/Investigator: David Lynch, MD, PhD - Children’s Hospital of Philadelphia

Award type: General Research Grant

Grant Title: Understanding ketogenesis in FRDA: Pathophysiology, biomarkers and nutritional therapies

Lay summary: The role of mitochondria in metabolism may mediate some components of FRDA, either in overall progression or in components such as diabetes. For example, platelets from patients with FRDA utilize fats in preference to sugars, suggestive of generalized metabolic dysfunction. Moreover, FRDA patients develop exercise intolerance, again suggesting that altered metabolism might play a role in the symptoms of FRDA. Understanding these events is important not only for creating new therapies for FRDA, but also for the development of new markers. The relative inaccessibility of affected tissue in FRDA and the difficulty of measuring frataxin levels in vivo require the development of novel biomarkers “close” to the events caused by frataxin loss. Metabolic and chemical imaging measurement of the markers in ketone utilization offer the possibility of providing such markers. Recent evidence from Dr. Lynch’s laboratory suggests a crucial role of metabolism of compounds called ketone bodies in the cause of FRDA. Frataxin controls ketone body metabolism through regulation of a specific enzyme, 3-Oxoacid CoA-Transferase 1 (OXCT1). This enzyme leads to use of ketone bodies as energy. Dr. Lynch and his group found that frataxin physically interacts with OXCT1 and blocks its degradation leading to failed ketone utilization when frataxin is not present. In this proposal, they will first define the diversity and significance of disruptions in ketone utilization in frataxin deficient cells. In addition, they will define the contribution of OXCT1 decreases to FRDA pathophysiology in animal models of FRDA. Finally, they will attempt to understand the role of abnormalities of ketone utilization in patients with FRDA. Collectively, these aims will determine the role of failed ketone utilization in features of FRDA.

PI/Investigator: Dezhen Wang, PhD - University of Pennsylvania

Award type: Postdoctoral Research Award

Grant Title: Unveil the link between lipid metabolism and cardiomyopathy in Friedreich’s ataxia using patient-specific iPSC-CMs

Lay summary: Frataxin is important for normal functions of metabolic enzymes, which catalyze chemical reactions to produce small molecules in our bodies. Lipids are some of these molecules. Previous studies have shown that specific lipids, called sphingolipids, are significantly increased in the FRDA heart tissue when compared with healthy controls. The basic components of more complex lipids, called free fatty acids, are the major source for producing energy in human heart and their dysregulation has been observed in different FRDA models. Since heart failure is the main cause of premature death in FRDA, it is important to study how these lipids are related to heart functions in FRDA. Monitoring the changes of these molecules may provide some measures of heart disease progression and give insight into new therapeutic avenues for FRDA. Because it is difficult to get human heart tissues for these studies, Dr. Wang plans to use an in vitro model (induced pluripotent stem cell-derived cardiomyocytes or iPSC-CM) to generate human cardiac cells from easily accessible human tissues (such as skin or blood). These cells maintain the phenotypes of human heart cells and can be used to study the heart disease. Dr Wang will use a very powerful technology called mass spectrometry to detect hundreds of different lipids in cardiac cells from healthy people and FRDA patients, and identify which lipids are different. He will also measure the activity of the chemical reactions and enzymes necessary for generating these lipids by mass spectrometry, assisted by stable isotope chemicals. These isotope chemicals will replace the non-isotope forms in cell culture medium and will be incorporated into the molecules that they want to study. By measuring the relative levels of isotope containing molecules, the activity of the reaction can be measured. This study aims to get a full picture of lipid dysregulation in FRDA.

PI/Investigator: Rucha Sarwade, PhD - Monash University, Australia

Award type: Postdoctoral fellowship

Grant Title: Investigating epigenetic silencing in Friedreich's Ataxia

Lay summary: Several models have been proposed to explain FXN gene silencing. Two eminent amongst them are; 1. Formation of unusual triplex DNA structures and R-loops that interferes with the RNA pol II processivity leading to transcriptional blockage, 2. Formation of heterochromatin. While research findings are consistent with both possibilities, neither of them adequately explains transcriptional silencing of FXN gene. This project aims to fill this critical knowledge gap and uncover sequential epigenetic events that are crucial to design effective treatment strategies for Friedreich's Ataxia (FRDA). In a parallel universe, studies on plants that have a peculiar growth defect due to an intronic triplet repeat expansion led to interesting observations. This plant model shares striking parallels at the molecular level with FRDA, suggestive of potential common underlying biology. In the plant model, repeat expansion causes accumulation of specific non-coding RNA species called siRNAs. These siRNAs lead to gene silencing by RdDM (RNA dependent DNA methylation) -dependent epigenetic modifications. Interestingly, repeat expansion-associated plant phenotype was rescued by mutations in enzymes that can cause post-translational modification of proteins. Excitingly, HETEROCHROMATIN PROTEIN 1 (HP1) that has been shown to be associated with epigenetic silencing in FRDA is known to be affected by such post-translational modifications. Dr. Sarwade hypothesizes that RNA -mediated epigenetic changes occurring at the FXN locus are maintained by protein modifications of chromatin modifiers such as, HP1. Through this fellowship, Dr. Sarwade intends to test whether the learnings from the plant research also translate to FRDA, using cell lines derived from patients.

Co-sponsor: fara Australia

PI/Investigator: Chen Liang, PhD - University of Rochester

Award type: Postdoctoral Fellowship

Grant Title: Pathophysiology of Muscle Dysfunction in Friedreich's Ataxia

Lay summary: FRDA is a deadly neurodegenerative disorder that is associated with significant muscle wasting and weakness. However, the reasons for this have not been extensively examined. Given that skeletal muscle plays a critical role in movement and daily activity, there is a pressing need to enhance our understanding of how altered skeletal muscle function contributes to the development and progression of FRDA. A major barrier to achieving this goal has been the lack of an animal model that accurately reflect the clinical features of FRDA in skeletal muscle. To overcome this barrier, Dr. Liang will generate two new pre-clinical mouse models, constitutive and inducible muscle-specific Fxn knockout mice. These mouse models will enable detailed analyses of the role of Fxn in muscle development and function, as well as the acute effect on muscle function of Fxn deficiency in adulthood. These mouse models will also be used to identify and test the efficacy of new interventions designed to counteract the deficits that result from Fxn deficiency during development and adulthood. This investigator and her mentors hypothesize that reduced Fxn expression in skeletal muscle results in muscle dysfunction and that restoration of Fxn expression ameliorates muscle dysfunction and prolongs survival. They further hypothesize that Fxn deficiency in skeletal muscle arises from mitochondrial damage due to mitochondrial Ca2+ overload and that muscle function is improved by blocking the activity of mitochondrial permeability transition pore (mPTP) through ablation of cyclophilin D. These hypotheses will be comprehensively evaluated using a multidisciplinary approach that includes muscle physiology, molecular biology, biochemistry, and Ca2+ imaging. The outcome of this study will provide new insights into the pathogenic mechanisms and treatment of the debilitating muscle dysfunction experienced by FRDA patients.

PI/Investigator: Sara Anjomani-Virmouni, PhD - Brunel University, London

Award type: General research grant

Grant Title: Sphingolipid rheostat as a potential target for Friedreich's Ataxia

Lay summary: Evidence indicates that defective sphingolipid metabolism may contribute to different neurodegenerative conditions, including Alzheimer’s disease, Huntington’s disease and Parkinson’s disease. Sphingolipid is a group of lipids important for the activity of the brain and therefore, disturbances in their metabolism can have a huge impact on brain function. Dr Anjomani Virmouni and her group have recently found that the sphingolipid levels and their related genes are altered in FRDA mouse and human samples, which may play a critical role in the disease progression. The aim of this project is to have a clear picture of the sphingolipid changes in FRDA and to identify potential and novel targets for the development of therapeutic strategies in the disease. This may involve the design of novel drugs or repurposing of currently licensed drugs.

PI/Investigators: Ricardo Mouro Pinto, PhD - Massachusetts General Hospital, Harvard Medical School & Caroline Benn, PhD - LoQus23 Therapeutics

Award type: General research grant

Grant Title: Testing whether somatic GAA expansions are a therapeutic target for FRDA

Lay summary: The inherited GAA repeat expansion in FA undergoes even further expansion in some parts of the body, in a process called “somatic instability”. These are the tissues that are most affected by the disease, such as the heart and the dorsal root ganglia in the spinal cord. In other neurodegenerative diseases that are also caused by repeat expansions, there is increasing evidence that somatic instability may contribute to disease. For this reason, researchers and companies are designing drugs that target somatic instability. Before these drugs can be considered potential therapies for FA, the contribution of somatic instability to disease progression needs to be established. The inherited GAA expansion causes a decrease in the production of the frataxin protein, which causes problems with energy generation in the cell. The question is whether somatic instability reduces frataxin production even further, making matters much worse in tissues such as the heart and dorsal root ganglia. To test this, Dr. Mouro Pinto and his collaborators will use an FA mouse model of somatic instability, in combination with patient-derived cell systems. The latter lack the multi-cellular environment of an animal, but are simpler and can give faster answers, while the former takes some time, but will give important clues on what is going on in a whole organism. The information obtained from this project is crucial to understanding whether drugs targeting somatic instability will make a viable therapeutic strategy to treat FA.

Supported by the Crisp Family Fund

PI/Investigator: Jordi Magrane, PhD - Weill Cornell Medicine

Award type: General research grant

Grant Title: Assessment of early somatosensory impairment in the KIKO mouse model of Friedreich's ataxia

Lay summary: Alterations in the normal development of the nervous system may explain some of the earliest pathology in Friedreich's ataxia (FRDA). Clinical and histological evidence suggest that FRDA patients may suffer from an impaired neurodevelopmental process that may occur during embryonic development or during early years after birth. No research studies have directly examined the consequences of frataxin reduction on the maturation of the nervous system during perinatal and early postnatal stages in mouse models of the disease. Dr. Magrane and his group have obtained experimental evidence using a well-characterized FRDA mouse model that frataxin deficiency causes a delay in the appearance of sensory and motor functions in neonates. Based on these novel observations, they aim to further investigate pathology in FRDA mouse pups affecting the nervous system structure and function, and to study the molecular mechanisms involved, with a focus on mitochondria. Successful completion of these studies will not only be important for our understanding of the pathogenesis of FRDA but will also validate the use of this model to evaluate the impact of early therapeutic approaches targeting the sensorimotor system.

PI/Investigator: Elisabetta Indelicato, MD, PhD - Medical University of Innsbruck, Austria

Award type: Postdoctoral Research Award

Grant Title: Hepcidin-Ferroportin axis in Friedreich's ataxia

Lay summary: One of the open questions in Friedreich´s ataxia (FRDA) is elucidating the role of iron in the development of the disease. In heart and brain of FRDA abnormal iron deposits are found in the mitochondria, the cell organelles mostly affected by the disease. Abnormal iron deposition is believed to trigger damage of mitochondria and contribute to disease manifestations. Over the past years, research in other fields identified the protein hepdicin (HAMP) as the main regulator of iron metabolism in the human body. HAMP is produced by the liver and in conditions of iron excess binds to ferroportin (FPN), an iron-exporting protein located in the cell membrane. This binding triggers FPN destruction and thus prevent the outflow of the ingested iron from the intestinal cells in the blood. Few studies in autopsies and in mouse models suggested that HAMP pathway may be altered in FRDA. To explore HAMP involvement in FRDA, Dr. Indelicato designed a pilot study in which she will measure levels of HAMP, iron and copper parameters, erythropoietin and erythroferrone (another human hormones with iron-regulating properties), as well as frataxin and FPN expression in blood cells of FRDA patients, carriers and control subjects. Moreover, Dr. Indelicato will study if iron accumulates in organs other than the nervous system and the heart by means of an MRI examination of the abdomen, which can visualize iron content in liver, pancreas and spleen. The aim of this proposal is to elucidate if the whole-body regulation of iron through the key factors HAMP and FNP is impaired in FRDA. These findings will help to guide therapeutic interventions on iron metabolism in FRDA and will help to understand if levels of HAMP may provide indirect information on disease state in FRDA.

Co-sponsors: fara Australia and FARA Ireland

PI/Investigator: Erin Seifert, PhD - Thomas Jefferson University

Award type: General research grant

Grant Title: Metabolic (mal)adaptation of heart and skeletal muscle to frataxin depletion

Lay summary: Dr. Seifert's lab has previously shown that in an animal model of FA (“UCLA” mice), heart function can be normal despite >98% loss of Frataxin (Fxn) and evidence of iron overload; normal function likely relies on preservation of fat oxidation and activation of processes that protect the heart. Interestingly, the hearts of Fxn-depleted mice show perturbations in 3 major signaling pathways, indicating that the Fxn-depleted heart is not normal. Some of these pathways may help to preserve heart function in the face of Fxn depletion, while others may lead to poor heart function if left unchecked. To understand how each pathway impacts the Fxn-depleted heart, the team will take advantage of existing small molecules: rapamycin (inhibits mTORC1 pathway), AICAR (activates AMPK pathway), and ISRIB (blocks the Integrated Stress Response pathway). The goal of this project is to test these small molecules in the UCLA mice, which have normal/compensated heart function, and in “MCK” mice that have complete Fxn loss in muscle soon after birth and show dramatic cardiac pathology. This group of investigators will determine if each of the 3 small molecules has a beneficial or harmful effect on heart function, size and metabolism in both mouse models. They will also determine if these molecules can protect skeletal muscle in these animals from declining in mass and strength. This study will fundamentally address whether the observed changes in signaling pathways are beneficial or maladaptive, and whether these pathways can be useful therapeutic targets.

PI/Investigator: Arnulf H. Koeppen, MD - VA Medical Center, Albany

Award type: General research grant

Grant Title: The pathogenesis of the major neural lesions in Friedreich ataxia: dorsal root ganglion and dentate nucleus

Lay summary: The mutation in Friedreich ataxia (FA) was established in 1996, but the mechanisms by which brain, spinal cord, dorsal root ganglia (DRG), and sensory peripheral nerves are damaged have remained elusive. The principal investigator hypothesizes that each one of the vulnerable tissues contains a unique set of proteins that undergo changes in the level of expression in response to frataxin deficiency in FA. The goal of this research is to identify those proteins-of-interest in FA that are up-regulated or down-regulated relative to levels in non-FA subjects, and to determine the functional consequences of these differences. Discovery and identification of FA-relevant proteins is accomplished by a combination of antibody microarrays with tissue lysates; slide technology (immunohistochemistry and immunofluorescence), gel electrophoresis and Western blotting. Antibody microarrays offer enough sensitivity to detect structural and signaling proteins relative to total protein. The success of proteomic methods depends on validation of antibodies and their reactivity with identifiable proteins. The investigator uses tissue samples obtained at the time of autopsy that were generously donated by the families of patients who succumbed to FA. The project has already yielded several important conclusions among which are: (1) Frataxin deficiency causes developmental hypoplasia of DRG; and (2) further destruction is due to proliferation of satellite cells that normally surround and nourish the nerve cells of DRG.

PI/Investigator: Yutaka Yoshida, PhD - Burke Neurological Institute & Joriene de Nooij, PhD - Columbia University

Award type: General research grant

Grant Title: Constancy of FRDA phenotypes across neuronal types and development

Lay summary: Despite remarkable progress, there remain considerable gaps in our knowledge of FRDA pathology in neuronal tissues. This lack of knowledge limits our ability to predict which new types of medication may be more effective in treating the disease and deserve a higher priority. This proposal is focused on three such areas that remain understudied. First, is the mechanism of disease the same in all neuronal tissues? Second, is the effect of the loss of FXN the same in a developing neuron as in a mature neuron? Lastly, does the loss of FXN in the developing neuron lead to permanent (genomic) alterations that cause or exacerbate disease in later life? Based on expertise in the development of two FRDA-affected neuronal tissues: proprioceptive sensory neurons (PSNs) and corticospinal neurons (CSNs), these investigators propose to perform a detailed comparative phenotypic and molecular analysis to examine the similarities or dissimilarities between the FRDA pathology in these two different tissues, and during their development. The result of these studies will inform design strategies for new therapeutics, or guide the evaluation of existing experimental treatments, particularly for those that pertain to neurological FRDA phenotypes.

Co-funding: CureFA Foundation

PI/Investigator: Stephen Chan, MD, PhD - University of Pittsburgh School of Medicine

Award type: General research grant

Grant Title: Frataxin deficiency as a cause of endothelial senescence and vasculature remodeling in Friedreich's ataxia

Lay summary: Friedreich's ataxia (FRDA) and deficiency of a factor called frataxin (FXN) results in a nerve disease affecting coordination and a condition called hypertrophic cardiomyopathy (HCM), marked by an abnormal thickening of the heart. While most of the research in FRDA has focused on nerves and heart muscle, alterations in blood vessels of the heart may worsen the disease in FRDA. But, the role of FXN in these blood vessels has never been defined. Dr. Chan and his team propose that FXN deficiency in FRDA causes DNA damage in lung and heart blood vessel cells to promote heart disease. First, they aim at determining whether FXN deficiency controls damage to genetic material called DNA in blood vessel cells. By studying human blood vessel cells cultured in a dish, this group will artificially manipulate the levels of FXN to determine the effects on DNA damage as well as cell growth and survival. To show the relevance of these findings to FRDA, they will study blood vessel cells originating from stem cells of patients with FRDA, coupled with analyses of heart tissue in FRDA patients. This group also will determine whether FXN deficiency in blood vessels causes heart disease. They have custom generated mice that carry an FXN mutation in blood vessel cells, heart muscle cells, both cell types, or neither. Using these mice, they plan to define the unique roles of FXN in these specific cell types and how they contribute uniquely to heart disease in FRDA. Finally, the team will determine if the drug ABT-263, known to be effective in reversing effects of DNA damage, can be effective in improving heart disease in mice relevant to FRDA.

Co-sponsor: The Peter and Thomas DiPietro Foundation, Inc

PI/Investigator: Jennifer Phillips-Cremins, PhD - University of Pennsylvania

Award type: General research grant

Grant Title: Elucidating the link between genome topology and repeat instability in Friedreich's Ataxia

Lay summary: DNA from a single human cell is more than 6 feet long when stretched out end to end. Over the last two decades, scientists have focused on elucidating the sequence of the linear DNA. It is now well established that information encoded in the DNA sequence shapes normal development of human traits, however the mechanisms underlying most diseases remain poorly understood. Recent technological advances have revealed that the 6 feet long DNA sequence is folded into sophisticated 3D configurations that enable it to fit into a nucleus the size of the head of a pin. This lab and others have recently discovered that the DNA's 3D structure is a critical regulator of gene expression patterns essential for normal human development. Cremins and her team have uncovered a striking new link between 3D genome folding and trinucleotide repeat (TNR) expansion disorders, like Friedreich's ataxia (FRDA). They have discovered that nearly all genes that cause TNR disorders are folded into the same unique 3D structure. This result is important because it provides new insight into the locations in the genome that are particularly vulnerable to mutation by incorrect sequence expansion. This group proposes to investigate the role of the 3D Epigenome in FRDA. They will (1) create maps of 3D genome misfolding and linear epigenetic mark alterations in induced pluripotent stem cell-derived neurons and cardiomyocytes from FRDA patients, (2) quantify the FRATAXIN GAA repeat tract length as a function of somatic cell state, and (3) computationally integrate 3D genome and linear epigenetic marks to assess the link to GAA tract length and FRATAXIN expression. Knowledge gained by this work will empower the long-term goal to engineer the 3D genome to reverse gene expression defects in human disease.

PI/Investigator: Giovanni Manfredi, MD, PhD - Weill Cornell Medicine & Helene Puccio, PhD - Institute NeuroMyoGène, Lyon, France

Award type: Award for Innovative Mindset

Grant Title: Mitochondrial integrated stress response in FA cardiomyopathy

Lay summary: The hypothesis of this proposal stems from the observation that death from cardiomyopathy in FA occurs in the third or fourth decade of life, but surprisingly the FA heart often maintains adequate function until shortly before death. This suggests that the FA heart is able to adapt, at least initially, to the defects caused by the loss of frataxin. This adaptation likely involves metabolic rewiring to allow the utilization of alternative energy sources and other adaptive events. The investigators propose that these events recapitulate the “mitochondrial integrated stress response” (well characterized in other mitochondrial diseases) which is an evolutionarily conserved response designed to help the organisms face periods of acute stress, but if chronic and unresolved, becomes “maladaptive”. This proposal aims at determining whether there is evidence of mitochondrial integrated stress response in the heart of an FA mouse model.

Co-sponsor: CureFA Foundation and fara Australia

PI/Investigator: Henry Houlden, MD, PhD - University College London, UK

Award type: Bronya J. Keats International Research Collaboration Award

Grant Title: Identification of genetic modifiers of Friedreich's ataxia

Lay summary: The GAA expansion length associated with Friedreich ataxia (FRDA) correlates with severity of symptoms and inversely with age of onset, particularly for the shorter allele (GAA1), with a prediction of 2.3 years earlier onset for every 100 GAA repeats added to GAA1. However, the GAA repeat size only accounts for between 36% to 56% of the variation in age of onset and the GAA expansion content has only been investigated for large scale interruptions. This suggests that other contributory factors such as non-coding or coding modifying genetic variation, environmental factors or small repeat sequence interruptions, may influence age of onset and severity. Identifying these factors in FRDA will be important in a number of ways, such as: 1. To define the individual genetic profile of each patient to help determine disease progression, predict clinical problems and understand allele lengths and age at onset, 2. To stratify patients more effectively for treatment trials and 3. The modifying molecular pathways identified will certainly improve our understanding of FRDA and may in themselves be potential therapeutic targets.

This international group collected a large series of FRDA from Europe/South America with DNA and core clinical features. To identify genetic modifying factors in FRDA, the following aims will be carried out:

A. A genome wide association study (GWAS) to identify genetic variants associated with (a) FRDA age at onset (AAO), (b) disease progression in FRDA and (c) investigate the overlap of modifiers associated with other repeat disorders (such as HD and SCAs). This part of project will be funded by Vertex Pharmaceuticals in a joint project with FARA. Vertex will fund genotyping of FRDA in each FRDA patient at University College London, to enable the collaboration with colleagues in the United States (Prof David Lynch and colleagues), where Vertex is currently funding SNP genotyping of their FRDA cases (to be completed in 2020) and enable comparison of data.

B. Identify biological pathways and gene networks influencing FRDA age at onset and severity.

C. Long-read sequencing of the FRDA GAA expansion to assess variation/and repeat changes in the FRDA expansion tract and the 5' and 3' flanking regions of the expansion, we will also carry out PacBio long-read sequencing of 400 FRDA patients.

The group is keen to be in contact with other research groups and clinical teams that are interested to be part of this study: email h.houlden@ucl.ac.uk

PI/Investigator: Mirella Dottori, PhD - University of Wollongong, Australia

Award type: General Research Grant

Grant Title: Investigating Proprioceptor Development and Function in Friedreich’s Ataxia

Lay summary: A deficiency in proprioception, the perception of the body position and movement, is one of the earliest symptoms observed in Friedreich ataxia (FA). The loss of proprioception is associated with prominent neurodegeneration in proprioceptor sensory neurons and within the cerebellum. A major question in FA research is ‘when’ does the proprioceptor impairment start and what is the mechanism underlying this in terms of having reduced Frataxin expression. There is some evidence to suggest that the defect in proprioceptor function is genetically determined rather than progressive post symptom onset. Other studies have reported that increased Frataxin levels is associated with proprioceptor/sensory neuronal differentiation, suggesting that low frataxin levels may impact proprioceptor development. This project aims to understand the neurodevelopment and neurodegenerative changes of FA and their implications for pathogenesis and therapies. Specifically, Dr. Dottori will use stem cells generated from FA patients to produce proprioceptor neurons as a model to investigate the mechanisms underlying proprioceptor dysfunction in FA. This is a necessary first step to determine ‘when’ and ‘how’ FA proprioception deterioration begins and when and how this can be halted and/or rescued by increasing Frataxin expression, and determine the appropriate timing of treatment.

Co-sponsor: fara Australia

PI/Investigator: Paola Costantini, PhD - University of Padova, Italy

Award type: General Research Grant

Grant Title: Three-dimensional mature cardiac microtissues from human induced pluripotent stem cells to explore mitochondrial dynamics, cardiac function and therapeutic options in Friedreich Ataxia

Lay summary: Myocardial energy production in significantly impaired in Friedreich ataxia patients and this reduction may even precede the development of tissue damage in the heart. These investigators have recently found that the shape of mitochondria, which is crucial for their function, is altered in isolated Friedreich ataxia patient cells and can be restored by genetically increasing the levels of the mitochondria shaping protein OPA1. In this project they will use an innovative tool, cardiac microtissues or “mini-hearts”, obtained from patient stem cells to investigate 1) if remodeling of the mitochondrial shape can correct cardiac dysfunction and 2) if increasing the levels of frataxin can correct the mitochondrial and cardiac defects. Modeling cardiac dysfunctions in Friedreich ataxia is a crucial and challenging task and cardiac microtissue is an advanced cellular model that will allow to mimic more closely the human myocardium. Defining the molecular features of the disease, in an appropriate cellular context, will facilitate the development of novel therapeutic strategies for Friedreich ataxia.

PI/Investigator: Vania Broccoli, PhD - San Raffaele Scientific Institute and CNR Institute of Neuroscience, Milan, Italy

Award type: General Research Grant

Grant Title: Advancing stem cell-based modeling of the proprioceptive neuronal circuit with dorsal root ganglia organoids and its impairment in Friedreich's ataxia

Lay summary: A major limitation in research on Friedreich's ataxia (FRDA) is the lack of experimental models to study dorsal root ganglia (DRG) sensory neurons. To fill this gap, the Broccoli group generated dorsal root ganglia organoids (DRGOs) by 3D in vitro differentiation of human reprogrammed stem cells (iPSCs). Organoids are cellular structures obtained in vitro where the different cell populations organize in the 3D space, closely recapitulating the organization and geometry of the tissue in vivo. Remarkably, the DRGOs generated by in vitro differentiation of iPSCs shared with native DRGs the expression of a large set of peripheral markers and robust electrophysiological activity. Furthermore, when co-cultured with human intrafusal muscle fibers, DRGO sensory neurons contacted their peripheral targets. Thus, for the first time an ordered circuit between the sensory neurons and their natural peripheral targets was established. Importantly, these investigators generated DRGOs from FRDA patient specific iPSCs and were able to recapitulate several aspects of the pathology including FXN silencing, diminished survival and defects in morphology and impaired formation of muscle spindles. Remarkably, these pathological features were extensively rescued when the entire FXN intron-1 was removed in iPSCs by using the CRISPR/Cas9 technology. This proposal will determine the exact neural cell diversity in DRGOs by single-cell RNA sequencing and establish an assay to evaluate the functional properties of the DRGO neuronal-muscle spindle connection in custom-made microfluidic devices. FRDA DRGOs will then be analyzed for pathophysiological dysfunctions in calcium handling, iron metabolism, inflammatory response and dynamics of mitochondria along axons by advanced imaging in novel microfluidic platforms. Finally, CRISPR/Cas9 corrected FRDA DRGOs will be analyzed to determine the extent of the recovery obtained after gene correction. This program will allow to determine the FRDA pathophysiological roots in a new biological system consisting of DRGO-derived human sensory neurons contacting the muscle cells, thus, modeling one of the neuronal circuits mostly affected in FRDA patients and responsible for gait and motor coordination dysfunctions.

Co-sponsor: FARA Ireland

PI/Investigator: Hélène Puccio PhD, Permanent research director (DR1) at the Institut National de la Santé et de la Recherche Médicale (INSERM). Group leader of the team "Fundamental and pathophysiological mechanisms implicated in ataxia" in the department of Translational Medicine and Neurogenetics at the Institut de Génétique et de Biologie Moléculaire et Cellulaire (IGBMC).

Award type: General Research Grant

Grant Title: Characterization of new humanized mouse model (TG(FXN)YG8Pook/800J) carrying 650-800 GAA repeats and stem cell therapies

Lay summary: Although several mouse models of FA have already been generated, no model to date faithfully reproduces the genetics and the phenotype associated with partial loss of frataxin. A new humanized mouse model carrying 800 GAA repeats within the human frataxin locus and knockout for the endogenous mouse frataxin gene (Tg(FXN)YG8Pook/800J) was recently derived at the Jackson laboratory (from the original Tg(FXN)YG8Pook/200 model from Dr. Pook's laboratory). While not yet characterized, this newly generated Tg(FXN)YG8Pook/800J model lab presents with very low levels of frataxin ubiquitously, based on data shared by Dr. Cat Lutz at the Jackson laboratory. It is genetically the most faithful model to human disease and should allow us to not only better characterize the epigenetic effects of the GAA expansion mutation, but also could be a more faithful model to uncover the pathophysiological mechanism of the disease. The main objective of this proposal is to fully characterized this new model for the FA community.

PIs/Investigators: David Lynch, MD, PhD, William Gaetz, PhD & Timothy Roberts, PhD - Children’s Hospital of Philadelphia

Award type: General Research Grant

Grant Title: Imaging of glutathione and GABA in the brain as biomarkers of Friedreich Ataxia

Lay summary: Frataxin deficiency in FA leads to changes in iron handling by the body as well as changes in metabolic pathways, the way chemicals are broken down in the body. Clinical research in FA has advanced rapidly in recent years, with the development of clinical measures and successful execution of clinical trials such as MOXIe (omaveloxolone). Still, future clinical trials need novel ways based on biology to assess outcomes in clinical studies, and to understand better how new drugs alter the causes of disease in patients with FA. At present, Spectroscopy (a type of MRI scan) can provide utility in some situations, but ongoing studies of brain structure and chemicals reflect the late pathophysiology of FA, and thus are unlikely to be early markers of disease or early effects of treatment. In this proposal, Dr. Lynch, Dr Gaetz and Dr Roberts will use advanced, edited magnetic resonance spectroscopy to assess brain levels of glutathione (a molecule that is an indicator of the presence of free radicals and oxidative stress) and the neurotransmitter γ-aminobutyric acid (GABA) (a compound involved in nerve communication in the brain), two potential markers of the proximal pathophysiology of FRDA. The hypothesis of this proposal is that assessment of brain glutathione and GABA levels provides accurate biomarkers of disease status in FA. In this pilot proposal, using advanced edited magnetic resonance spectroscopy, the investigators will assess GABA and glutathione in the brain motor cortex of 10 FA subjects and 10 age-matched controls. They will also assess the relationship of glutathione and GABA motor cortex levels to markers of FA disease severity. Finally, 5 FA subjects will be tested after initiation of omaveloxolone therapy (as it becomes clinically available). This will allow to determine whether glutathione spectroscopy responds to the new drug omaveloxolone and whether imaging of glutathione and/or GABA will advance monitoring of FA.

PI/Investigator: Louise Corben, PhD - Murdoch Children’s Research Institute

Award type: General Research Grant

Grant Title: Measuring ataxia in children with Friedreich ataxia

Lay summary: Friedreich ataxia (FA) impacts many aspects of daily life including walking, speech, arm function and vision. The common element underscoring this impact is ataxia or incoordination. Ataxia in FA is measured by clinical rating scales such as the modified Friedreich’s Ataxia Rating Scale (mFARS). In children under the age of 12 years measurement of ataxia may be difficult as the system that controls movement is still maturing, making it difficult to discern by a rating scale, what movements are ataxic and what is related to normal maturation. It is important to develop valid measurements of ataxia in younger children so we can potentially monitor their response to new treatments. Dr. Corben has developed devices that use movement analysis technology to measure ataxia. She and her collaborators plan to evaluate the capacity of these devices called the Ataxia Instrumented Measure –Cup (AIM-C) and Ataxia Instrumented Measure – Pendant (AIM-P) to measure arm movement and balance in 12 children with, and 12 children without FA. If they are able to demonstrate that the AIM-C and AIM-P can detect and measure ataxia in young children with FA, they will then conduct a longitudinal trial to evaluate if these devices are useful as outcome measures for young children with FA participating in clinical trials.

PI/Investigators: Joseph Baur, PhD – University of Pennsylvania & Shana McCormack, MD – Children’s Hospital of Philadelphia

Award type: Kyle Bryant Translational Research Award

Grant Title: Detection and enhancement of tissue NAD+ levels in Friedreich’s Ataxia

Lay summary: Nicotinamide adenine dinucleotide (NAD+) is a critical co-factor for cellular metabolism and signaling. It is especially important for energy generation by mitochondria, the “powerhouse of the cell.” Recently, it has been shown that NAD+ is lower in failing hearts, and that boosting NAD+ improves heart function in animal models. In mice with heart-specific loss of frataxin, supplementing NAD+ with nicotinamide mononucleotide (NMN) improved heart function. Dr Baur and his group were able to enhance mitochondrial function with NAD+ supplementation in mice that have reduced frataxin levels in their whole bodies, which is thought to better reflect the human disease. In collaboration with Dr McCormack and other scientists at the University of Pennsylvania and the Children’s Hospital of Philadelphia, he plans to extend these findings in mice and evaluate tissue NAD+ levels in human subjects with FA. Mice with low levels of frataxin will be treated with nicotinamide riboside (NR) or NMN to increase NAD+ levels. Heart function will be evaluated by echocardiography and mitochondria will be tested for the capacity to generate energy. In addition, they will measure the levels of metabolites in the brain, heart tissue and mitochondria under each condition. In human subjects, these investigators will take advantage of a recently developed method for detection of NAD+ in living tissue by proton magnetic resonance spectroscopy (MRS). This method will be used to measure NAD+ in both the brain and skeletal muscle of subjects with FA and healthy controls. Together, these studies have the potential to uncover novel biomarkers and will guide decisions concerning the suitability and therapeutic potential of NAD+ precursors in individuals with FA.

PI/Investigators: Ankur Jain, PhD - Whitehead Institute for Biomedical Research & Ricardo Mouro Pinto, PhD - Harvard Medical School and Massachusetts General Hospital

Award type: Award for Innovative Mindset

Grant Title: A New Ultrasensitive Single-Molecule Assay for Frataxin Measurement

Lay summary: These investigators propose to develop a sensitive and quantitative assay for measuring frataxin levels that could help drug development in FA as well as advance our understanding of disease mechanism. Direct measurement of frataxin remains challenging owing to its low abundance and the inherent detection noise of commonly used assays. Dr Jain and Dr Mouro Pinto propose to overcome this hurdle by implementing a technology that allows detection of very small amounts of molecules directly from serum, blood, or tissue extracts. This method, called SiMPull, combines immuno pull-down (isolating a molecule with antibodies) with single-molecule microscopy, allowing to visualize single protein molecules with a microscope. This assay was recently utilized to measure a variety of biomarkers in blood present at very low concentrations. The investigators hypothesize that the increased sensitivity, quantitative readout, and dynamic range afforded by SiMPull will allow to accurately quantify frataxin levels, including measurements of subtle changes that are undetectable by conventional methods. SiMPull may provide opportunities to use frataxin in accessible biospecimen such as blood, serum, and cerebrospinal fluid as a biomarker for disease progression and for assessing the effectiveness of therapies in clinical trials.

PI/Investigators: Mark Payne, MD - Indiana University School of Medicine & Thomas O’Connell, PhD - Indiana University School of Medicine

Award type: General Research Grant

Grant Title: Diagnostic and Mechanistic Validation of a Metabolic Biomarker Panel to Guide Therapeutic Interventions in Friedreich’s Ataxia

Lay summary: A key roadblock for all therapies has been a lack of biomarkers which can rapidly report on the efficacy and/or toxicity of a therapeutic intervention, and the biochemistry of the disease. In Friedreich Ataxia, affected tissues, such as heart or brain, cannot be assayed to quantify frataxin levels in response to therapies. The goal of this project is to conduct pre-clinical studies on a new set of biomarkers that Dr. Payne and Dr. O’Connell have discovered that reveals a distinct and highly specific metabolic profile in FA patients. Dr. Payne and Dr. O’Connell will test the hypothesis that a metabolic panel can be used as biomarkers for loss or recovery of FXN expression. They will first refine and optimize the biomarker panel using blood samples from 40 FA and 40 control subjects and then validate the performance of the defined biomarker panel using a larger, separate cohort of 60 FA and 60 control subjects. The investigators will subsequently evaluate the response of the biomarker panel to therapeutic intervention using TAT-FXN in a mouse model of FA. The short-term goal is to develop a biomarker panel for FA that quickly reports on disease state and efficacy of therapeutic intervention. The long-term goal of these studies is to understand the metabolic derangements in FA that determine patient outcomes.

PI/Investigator: Chad Heatwole, MD - University of Rochester Medical Center, NY

Award type: General Research Grant

Grant Title: LEOPARD-FA: Longitudinal Endpoint Optimization to Provide an Assessment of Relevant Drugs in Friedreich’s Ataxia

Lay summary: Lay summary: Patients with Friedreich’s Ataxia (FA) experience a variety of life-altering symptoms. As new therapies and clinical trials are planned for FA, it is important for researchers, clinicians, patients, and regulatory agencies to have clinical trial tools that are capable of detecting meaningful changes in the symptoms and issues that are most important to patients. Dr. Heatwole previously developed two state-of-the-art outcome measures for patients with FA (The FA Health Indices). The first instrument, the Friedreich’s Ataxia Health Index (FA-HI), measures symptomatic burden using the perspective of the patient. The second instrument, the Friedreich’s Ataxia Caregiver Reported Health Index (FACR-HI), measures symptomatic burden in younger children with FA and is completed by caregivers. Together, these instruments provide a mechanism for a patient’s or caregiver’s perception of the effectiveness of a therapy to be recorded and utilized during a clinical trial. While these instruments are highly reliable, versatile, multifaceted, and relevant to FA patients, they have not yet been evaluated in longitudinal studies. Such assessments are necessary to complete the validation process for the instruments, satisfy FDA guidance criteria for their use in drug-labeling claims, optimize the responsiveness of the instruments, and prepare them for global use as relevant markers of symptomatic disease burden. This research will satisfy existing needs by developing, validating, assessing, and optimizing the responsiveness, relevance, performance, and usability of the FA-Health Indices. Dr. Heatwole’s group will accomplish this using accepted methodology and the parallel utilization of the FA-Health Indices in: 1) An 18-month longitudinal validation study utilizing the FA Global Patient Registry; and, 2) The ongoing Friedreich’s Ataxia Clinical Outcome Measures Study (FACOMS). In addition, natural history data in FA will be collected and analyzed. These data will: 1) demonstrate how disease progresses over time in FA, 2) identify which areas of FA symptomatic burden progress the fastest, and, 3) determine which demographic features are associated with a faster or slower progression of disease. Through this research, these investigators will also generate responsiveness data and performance metrics for the FA-Heath Indices and their subscales to assist in the design of future clinical studies. At the completion of this work, the FA research community will have two fully-validated and patient-centered outcome measures to promote the development of meaningful therapies in FA.

Co-sponsor: fara Australia

PI/Investigator: David Herrmann, MBBCh - University of Rochester Medical Center, NY

PI/Investigator: Peter Creigh, MD - University of Rochester Medical Center, NY

Award type: General Research Grant

Grant Title: In-Vivo Confocal Imaging of Meissner's Corpuscles as a Biomarker in Friedreich's Ataxia (FA)

Lay summary: This is an extension of an observational study designed to determine the potential role of Meissner Corpuscle (MC) Imaging as a biomarker in FA. In the first phase, 16 FA patients and 16 healthy controls were recruited and studied over 12 months with a series of potential biomarkers. Several of these biomarkers looked promising, and this study is being extended to include an additional 11 participants with FA, and the study will continue for up to 24 months. This is a two-part study. An initial cross-sectional phase assessed the utility of MC imaging, quantitative sensory testing (QST) (touch-pressure, vibration (timed and quantitative) and cold detection thresholds), as biomarkers in FA. These candidate biomarkers will now be assessed longitudinally in a larger cohort of patients and for a longer period in this extension phase. The study will include a screening and baseline visit on the same day and 3 subsequent visits, conducted 6, 12 and 24 months after the initial study visit. The original study included only screening, baseline 6 and 12 month visits, and in this extension a 24 month measurement will be added.

Co-Sponsor: Voyager Therapeutics

PI/Investigator: Laura Kropp, PhD, MPH - Stealth BioTherapeutics

Award type: Keith Michael Andrus Cardiac Research Award

Grant Title: Advancing novel mitochondrial therapies for FA cardiomyopathy: a pragmatic collaboration to move new therapies forward

Lay summary: In Friedreich’s ataxia, frataxin deficiency causes mitochondria dysregulation and impaired cellular energy production. Stealth BioTherapeutics has recently developed a series of new compounds that were designed to address dysregulated mitochondria in FA cardiomyopathy. These compounds have been developed to correct the impairments in bioenergetics of the cell and to prevent iron-mediated cell death (known as ferroptosis). Three compounds have been identified with the potential to mitigate mitochondrial dysfunction in FA cardiomyopathy: the first compound helps with improving energy production in mitochondria, the second prevents ferroptosis in cellular assays, and the third demonstrates potential “dual pharmacology” by improving both pathways. In this study, Dr. Kropp will test whether this series of compounds can ameliorate signs and disease biomarkers of cardiomyopathy in a mouse model of FA. She will also characterize the mechanism of these drugs by measuring their effect on energy production and ferroptosis in the FA mouse heart. These studies may provide new scientific insight as to whether inhibiting both pathways will be superior, or equipotent, to mechanistic approaches that inhibit either pathway alone. Successful completion of these studies will help to advance the development of a drug candidate for FA cardiomyopathy.

PI/Investigator: Jarmon Lees, PhD - St Vincent's Institute of Medical Research, Melbourne, Australia

Award type: Postdoctoral Research Award

Grant Title: Investigating sympathetic nervous dysregulation in the pathogenesis of cardiomyopathy in Friedreich's ataxia

Lay summary: Major hurdles in the development of effective therapies to combat Friedreich's ataxia (FRDA)-associated heart disease include the difficulty of obtaining human heart tissue for study, and animal models of FRDA that do not sufficiently recapitulate the human disease. To this end, disease modelling using human induced pluripotent stem cells (iPSCs) may provide a solution by delivering models that faithfully represent human diseases. iPSCs can multiply indefinitely and be differentiated into any cell type in the body. Hence, FRDA heart tissue which can be made from FRDA-iPSCs, is a promising tool for the study of FRDA heart disease and for the development of new therapies.

Clinical studies of FRDA have reported dysfunction of the heart's autonomic nervous system, the electrical system that controls how fast or slow the heart beats. In FRDA this manifests as a faster resting heart rate, increased noradrenaline production, and a higher incidence of cardiac arrhythmias. It is plausible that both the heart disease and arrhythmias, commonly manifested in FRDA patients, are linked to this dysfunction of the autonomic nervous system. Previous research has focused mainly on the heart muscle (i.e. cardiomyocytes), but has not examined the heart's autonomic nervous system.

In this proposal, we aim to investigate the causes of the heart disease in FRDA by generating cardiomyocytes and autonomic neurons from FRDA-iPSCs to study the development of FRDA-associated heart disease. We will examine the cardiomyocytes and neurons in isolation, and then assess the interaction between the cardiomyocytes and the neurons by growing the cells using our cutting-edge 3D multicellular beating cardiac organoids composed of cardiomyocytes, autonomic neurons and blood vessels. This new model of human heart tissue is a marked improvement over older simplistic models that lack blood vessels and neurons which are essential cellular components in the heart for disease development and the discovery of new effective treatments. This organoid model is an advanced pre-clinical human platform that can faithfully recapitulate heart disease. This proposal aims to unravel the causes of heart disease in FRDA, with a particular focus on the contribution of dysfunctional autonomic neuronal activity. The outcomes of this study will potentially provide a novel target for therapeutic interventions to limit or prevent morbidity and mortality in FRDA.

Co-sponsor: fara Australia

PI/Investigator: Marcondes França Jr, MD, PhD and Thiago de Rezende, MSc - University of Campinas, Brazil

Award type: Postdoctoral Research Award

Grant Title: Cardiac Imaging Biomarkers in Friedreich's Ataxia

Lay summary: Biomarkers are urgently needed to assist in the clinical care and the design of clinical trials for Friedreich´s ataxia (FRDA). Neuroimaging-based parameters have emerged as potential candidates, although further studies are necessary to validate them. In particular, cardiac magnetic resonance imaging (cMRI) has emerged as a promising diagnostic technique. In FRDA, cardiac studies have not received as much research interest as the neurological manifestations, despite heart failure being the main cause of death in such patients. For this reason, further studies in this area are needed to provide relevant information on the natural history and pathophysiology of the disease, in order to identify useful and sensitive biomarkers for clinical trial and follow-up. Therefore, this research proposal centers on the following objectives: 1. To characterize and quantify cardiac damage in pediatric patients with FRDA, patients with long standing FRDA and patients with late-onset FRDA (LOFA); 2. To characterize longitudinal progression of such damage in each of these groups; 3. To investigate whether image parameters correlate with clinical measures, mainly ataxia severity.

PI/Investigators: Manuela Corti, PhD & Tanja Taivassalo, PhD – University of Florida

Award type: Award for Innovative Mindset

Grant Title: Functional electrical stimulation (FES) cycling training to improve motor and cardiac functions in patients with Friedreich’s Ataxia: a feasibility and efficacy study

Lay summary: The purpose of this exploratory study is to assess the feasibility and potential efficacy of a novel therapeutic strategy involving Functional Electrical Stimulation (FES) cycle exercise training in patients with Friedreich’s Ataxia (FA). This pilot study will take advantage of innovative FES technology paired with isokinetic cycling provided by the MyoCycle Home FES Cycling Therapy System (Myolyn, LLC, Gainesville, Florida) and use a home-based, remotely supervised training strategy to encourage feasibility and compliance to the protocol. This study will recruit six non-ambulatory FA patients to assess the effect of training with cycling plus FES versus cycling alone. The investigators will test feasibility, motor function and exercise capacity using integrative, non-invasive approaches, including novel magnetic resonance imaging techniques to assess functional and morphological changes in the heart and skeletal muscle.

Co-sponsor: AFAF