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Item Cardiovascular Research in Friedreich Ataxia: Unmet Needs and Opportunities(Elsevier, 2022-07-13) Payne, R. Mark; Pediatrics, School of MedicineFriedreich Ataxia (FRDA) is an autosomal recessive disease in which a mitochondrial protein, frataxin, is severely decreased in its expression. In addition to progressive ataxia, patients with FRDA often develop a cardiomyopathy that can be hypertrophic. This cardiomyopathy is unlike the sarcomeric hypertrophic cardiomyopathies in that the hypertrophy is associated with massive mitochondrial proliferation within the cardiomyocyte rather than contractile protein overexpression. This is associated with atrial arrhythmias, apoptosis, and fibrosis over time, and patients often develop heart failure leading to premature death. The differences between this mitochondrial cardiomyopathy and the more common contractile protein hypertrophic cardiomyopathies can be a source of misunderstanding in the management of these patients. Although imaging studies have revealed much about the structure and function of the heart in this disease, we still lack an understanding of many important clinical and fundamental molecular events that determine outcome of the heart in FRDA. This review will describe the current basic and clinical understanding of the FRDA heart, and most importantly, identify major gaps in our knowledge that represent new directions and opportunities for research.Item Cardiovascular Research in Friedreich Ataxia: Unmet Needs and Opportunities(Elsevier, 2022-12) Payne, R. Mark; Pediatrics, School of MedicineFriedreich Ataxia (FRDA) is an autosomal recessive disease in which a mitochondrial protein, frataxin, is severely decreased in its expression. In addition to progressive ataxia, patients with FRDA often develop a cardiomyopathy that can be hypertrophic. This cardiomyopathy is unlike the sarcomeric hypertrophic cardiomyopathies in that the hypertrophy is associated with massive mitochondrial proliferation within the cardiomyocyte rather than contractile protein overexpression. This is associated with atrial arrhythmias, apoptosis, and fibrosis over time, and patients often develop heart failure leading to premature death. The differences between this mitochondrial cardiomyopathy and the more common contractile protein hypertrophic cardiomyopathies can be a source of misunderstanding in the management of these patients. Although imaging studies have revealed much about the structure and function of the heart in this disease, we still lack an understanding of many important clinical and fundamental molecular events that determine outcome of the heart in FRDA. This review will describe the current basic and clinical understanding of the FRDA heart, and most importantly, identify major gaps in our knowledge that represent new directions and opportunities for research.Item The current state of biomarker research for Friedreich's ataxia: a report from the 2018 FARA biomarker meeting(Future Science Group, 2019-06-28) Blair, Ian A.; Farmer, Jennifer; Hersch, Steven; Larkindale, Jane; Lynch, David R.; Napierala, Jill; Napierala, Marek; Payne, R. Mark; Subramony, Sub H.; Department of Medicine, IU School of MedicineThe 2018 FARA Biomarker Meeting highlighted the current state of development of biomarkers for Friedreich's ataxia. A mass spectroscopy assay to sensitively measure mature frataxin (reduction of which is the root cause of disease) is being developed. Biomarkers to monitor neurological disease progression include imaging, electrophysiological measures and measures of nerve function, which may be measured either in serum and/or through imaging-based technologies. Potential pharmacodynamic biomarkers include metabolic and protein biomarkers and markers of nerve damage. Cardiac imaging and serum biomarkers may reflect cardiac disease progression. Considerable progress has been made in the development of biomarkers for various contexts of use, but further work is needed in terms of larger longitudinal multisite studies, and identification of novel biomarkers for additional use cases.Item Design and Rationale of the Fontan Udenafil Exercise Longitudinal (FUEL) Trial(Elsevier, 2018) Goldberg, David J.; Zak, Victor; Goldstein, Bryan H.; McCrindle, Brian W.; Menon, Shaji C.; Schumacher, Kurt R.; Payne, R. Mark; Rhodes, Jonathan; McHugh, Kimberly E.; Penny, Daniel J.; Trachtenberg, Felicia; Hamstra, Michelle S.; Richmond, Marc E.; Frommelt, Peter C.; Files, Matthew D.; Yeager, James L.; Pemberton, Victoria L.; Stylianou, Mario P.; Pearson, Gail D.; Paridon, Stephen M.; Pediatrics, School of MedicineThe Fontan operation creates a circulation characterized by elevated central venous pressure and low cardiac output. Over time, these characteristics result in a predictable and persistent decline in exercise performance that is associated with an increase in morbidity and mortality. A medical therapy that targets the abnormalities of the Fontan circulation might, therefore, be associated with improved outcomes. Udenafil, a phosphodiesterase type 5 inhibitor, has undergone phase I/II testing in adolescents who have had the Fontan operation and has been shown to be safe and well tolerated in the short-term. However, there are no data regarding the long-term efficacy of udenafil in this population. The Fontan Udenafil Exercise Longitudinal (FUEL) Trial is a randomized, double blind, placebo controlled phase III clinical trial being conducted by the Pediatric Heart Network in collaboration with Mezzion Pharma Co., Ltd. This trial is designed to test the hypothesis that treatment with udenafil will lead to an improvement in exercise capacity in adolescents who have undergone the Fontan operation. A safety extension trial, the FUEL Open-Label Extension Trial (FUEL OLE), offers the opportunity for all FUEL subjects to obtain open-label udenafil for an additional 12 months following completion of FUEL, and evaluates the long-term safety and tolerability of this medication. This manuscript describes the rationale and study design for FUEL and FUEL OLE. Together, these trials provide an opportunity to better understand the role of medical management in the care of those who have undergone the Fontan operation.Item DISHEVELLED-ASSOCIATED ACTIVATOR OF MORPHOGENESIS 1 (DAAM1) IS REQUIRED FOR HEART MORPHOGENESIS(2010-02-02T19:55:35Z) Li, Deqiang; Shou, Weinian; Field, Loren J.; Payne, R. Mark; Zhang, XinDishevelled-associated activator of morphogenesis 1 (Daam1), a member of the formin protein family, has been implicated in the non-canonical Wnt mediated Planar Cell Polarity (PCP) signaling pathway. Although the studies in Drosophila Daam1 and Xenopus Daam1 generated inconsistent conclusions regarding the function of Daam1, the biological function of mammalian Daam1 was not evaluated. In this study, we used a mouse promoter trap technology to create Daam1 deficient mice to analyze the role of Daam1 in embryonic development and organogenesis. Daam1 is highly expressed in the developing heart. The majority of Daam1 mutant mice died between embryonic day 14.5 and birth, exhibiting a variety of heart defects, which include ventricular noncompaction, ventricular septal defects, and double outlet right ventricle. About 10% mutant mice survive to adulthood, and these survivors do not show significantly compromised heart function based on echocardiographic analyses. However, all of these mutant survivors have ventricular noncompaction with a range of severities. A conditional rescue experiment using a cardiac specific Cre mouse line, Nkx2-5Cre, confirmed that the cardiac defects are the primary cause of death in Daam1 mutants. Both in vivo and ex vivo analyses revealed that Daam1 is essential for regulating non-sarcomeric filamentous actin assembly in cardiomyocytes, which likely contributes to cardiac morphogenesis and ventricular wall maturation. Biochemical studies further suggested that Daam1 is not a key signaling component in regulating the activation of small GTPases, such as RhoA, Rac1 and Cdc42. In conclusion, our studies demonstrated that Daam1 is essential for cardiac morphogenesis likely through its regulation of cytoskeletal architecture in the developing cardiomyocytes.Item Examination of Adverse Reactions After COVID-19 Vaccination Among Patients With a History of Multisystem Inflammatory Syndrome in Children(American Medical Association, 2023-01-03) Elias, Matthew D.; Truong, Dongngan T.; Oster, Matthew E.; Trachtenberg, Felicia L.; Mu, Xiangyu; Jone, Pei-Ni; Mitchell, Elizabeth C.; Dummer, Kirsten B.; Sexson Tejtel, S. Kristen; Osakwe, Onyekachukwu; Thacker, Deepika; Su, Jennifer A.; Bradford, Tamara T.; Burns, Kristin M.; Campbell, M. Jay; Connors, Thomas J.; D'Addese, Laura; Forsha, Daniel; Frosch, Olivia H.; Giglia, Therese M.; Goodell, Lauren R.; Handler, Stephanie S.; Hasbani, Keren; Hebson, Camden; Krishnan, Anita; Lang, Sean M.; McCrindle, Brian W.; McHugh, Kimberly E.; Morgan, Lerraughn M.; Payne, R. Mark; Sabati, Arash; Sagiv, Eyal; Sanil, Yamuna; Serrano, Faridis; Newburger, Jane W.; Dionne, Audrey; Pediatric Heart Network MUSIC Study Investigators; Pediatrics, School of MedicineImportance: Data are limited regarding adverse reactions after COVID-19 vaccination in patients with a history of multisystem inflammatory syndrome in children (MIS-C). The lack of vaccine safety data in this unique population may cause hesitancy and concern for many families and health care professionals. Objective: To describe adverse reactions following COVID-19 vaccination in patients with a history of MIS-C. Design, setting, and participants: In this multicenter cross-sectional study including 22 North American centers participating in a National Heart, Lung, and Blood Institute, National Institutes of Health-sponsored study, Long-Term Outcomes After the Multisystem Inflammatory Syndrome in Children (MUSIC), patients with a prior diagnosis of MIS-C who were eligible for COVID-19 vaccination (age ≥5 years; ≥90 days after MIS-C diagnosis) were surveyed between December 13, 2021, and February 18, 2022, regarding COVID-19 vaccination status and adverse reactions. Exposures: COVID-19 vaccination after MIS-C diagnosis. Main outcomes and measures: The main outcome was adverse reactions following COVID-19 vaccination. Comparisons were made using the Wilcoxon rank sum test for continuous variables and the χ2 or Fisher exact test for categorical variables. Results: Of 385 vaccine-eligible patients who were surveyed, 185 (48.1%) received at least 1 vaccine dose; 136 of the vaccinated patients (73.5%) were male, and the median age was 12.2 years (IQR, 9.5-14.7 years). Among vaccinated patients, 1 (0.5%) identified as American Indian/Alaska Native, non-Hispanic; 9 (4.9%) as Asian, non-Hispanic; 45 (24.3%) as Black, non-Hispanic; 59 (31.9%) as Hispanic or Latino; 53 (28.6%) as White, non-Hispanic; 2 (1.1%) as multiracial, non-Hispanic; and 2 (1.1%) as other, non-Hispanic; 14 (7.6%) had unknown or undeclared race and ethnicity. The median time from MIS-C diagnosis to first vaccine dose was 9.0 months (IQR, 5.1-11.9 months); 31 patients (16.8%) received 1 dose, 142 (76.8%) received 2 doses, and 12 (6.5%) received 3 doses. Almost all patients received the BNT162b2 vaccine (347 of 351 vaccine doses [98.9%]). Minor adverse reactions were observed in 90 patients (48.6%) and were most often arm soreness (62 patients [33.5%]) and/or fatigue (32 [17.3%]). In 32 patients (17.3%), adverse reactions were treated with medications, most commonly acetaminophen (21 patients [11.4%]) or ibuprofen (11 [5.9%]). Four patients (2.2%) sought medical evaluation, but none required testing or hospitalization. There were no patients with any serious adverse events, including myocarditis or recurrence of MIS-C. Conclusions and relevance: In this cross-sectional study of patients with a history of MIS-C, no serious adverse events were reported after COVID-19 vaccination. These findings suggest that the safety profile of COVID-19 vaccination administered at least 90 days following MIS-C diagnosis appears to be similar to that in the general population.Item Gene therapy for Friedreich ataxia: Too much, too little, or just right?(Elsevier, 2022-03-04) Payne, R. Mark; Pediatrics, School of MedicineItem Identification and characterization of altered mitochondrial protein acetylation in Friedreich's ataxia cardiomyopathy(Hindawi Publishing Corporation and Oxford Journals and SAGE Journals, 2011) Wagner, Gregory Randall; Payne, R. Mark; Dong, X. Charlie; Herbert, Brittney-Shea; Shou, WeinianFriedreich’s Ataxia (FRDA) is a rare and poorly understood autosomal recessive disease caused by a pathological deficiency of the mitochondrial protein frataxin. Patients suffer neurodegeneration, ataxia, diabetes, and heart failure. In an effort to understand the mechanisms of heart failure in FRDA, we investigated the role of the protein modification acetylation, which is highly abundant on mitochondrial proteins and has been implicated in regulating intermediary metabolism. Using mouse models of FRDA, we found that cardiac frataxin deficiency causes progressive hyperacetylation of mitochondrial proteins which is correlated with loss of respiratory chain subunits and an altered mitochondrial redox state. Mitochondrial protein hyperacetylation could be reversed by the mitochondria-localized deacetylase SIRT3 in vitro, suggesting a defect in endogenous SIRT3 activity. Consistently, frataxin-deficient cardiac mitochondria showed significantly decreased rates of fatty acid oxidation and complete oxidation to carbon dioxide. However, the degree of protein hyperacetylation in FRDA could not be fully explained by SIRT3 loss. Our data suggested that intermediary metabolites and perhaps acetyl-CoA, which is required for protein acetylation, are accumulating in frataxin-deficient mitochondria. Upon testing the hypothesis that mitochondrial protein acetylation is non-enzymatic, we found that the minimal chemical conditions of the mitochondrial matrix are sufficient to cause widespread non-enzymatic protein acetylation in vitro. These data suggest that mitochondrial protein hyperacetylation in FRDA cardiomyopathy mediates progressive post-translational suppression of mitochondrial oxidative pathways which is caused by a combination of SIRT3 deficiency and, likely, an accumulation of unoxidized acetyl-CoA capable of initiating non-enzymatic protein acetylation. These findings provide novel insight into the mechanisms underlying a poorly understood and fatal cardiomyopathy and highlight a fundamental biochemical mechanism that had been previously overlooked in biological systems.Item Identification of altered Ras signaling and intermediate filament hyperphosphorylation in giant axonal neuropathy(2015) Martin, Kyle B.; Payne, R. Mark; Cummins, Theodore R.; Morral, Nuria; Wek, Ronald C.Giant axonal neuropathy (GAN) is a rare genetic disease that causes progressive damage to the nervous system. Neurons in GAN patients develop an abnormal organization of cytoskeletal proteins called intermediate filaments (IFs), which normally provide strength and support for the overall cell structure. The irregular IF structure in GAN patient neurons leads to a progressive loss of motor skills in children and subsequent death in adolescence. GAN is caused by reduced levels of the gigaxonin (Giga) protein. Giga functions to control the degradation of other cellular proteins, and the loss of Giga in GAN cells results in significantly elevated levels of the galectin-1 (Gal-1) protein. Gal-1 stabilizes the active form of the Ras signaling protein, which functions as a molecular switch to regulate the phosphorylation and subsequent organization of IFs. The connection between these pathways led us to propose that Giga regulates IF phosphorylation and structure by modulating Ras signaling through the degradation of Gal-1. Using GAN patient cells, we demonstrated that restoring Giga reduced Gal-1 protein levels, decreased IF phosphorylation, and reestablished normal IF organization. Similar effects of reduced IF phosphorylation and improved IF structure were also obtained in GAN cells by directly decreasing the protein levels of either Gal-1, or downstream Ras signaling proteins. Taken together, these results demonstrate that the loss of Giga induces Gal-1 mediated activation of Ras signaling, thereby leading to the increased IF phosphorylation and abnormal IF structure observed in GAN cells. Identification of aberrant Ras signaling is significant because it is the first to specify a mechanism by which the loss of Giga leads to the development of GAN and provides targets for novel drug therapies for the treatment of this currently immedicable genetic disease.Item Metabolic profiles identify circulating biomarkers associated with heart failure in young single ventricle patients(Springer, 2021-10-03) O’Connell, Thomas M.; Logsdon, David L.; Mitscher, Gloria; Payne, R. Mark; Otolaryngology -- Head and Neck Surgery, School of MedicineBackground: Children and young adults with single ventricle (SV) heart disease frequently develop heart failure (HF) that is intractable and difficult to treat. Our understanding of the molecular and biochemical reasons underlying this is imperfect. Thus, there is an urgent need for biomarkers that predict outcome and provide a rational basis for treatment, and advance our understanding of the basis of HF. Objective: We sought to determine if a metabolomic approach would provide biochemical signatures of HF in SV children and young adults. If significant, these analytes might serve as biomarkers to predict outcome and inform on the biological mechanism(s) of HF. Methods: We applied a multi-platform metabolomics approach composed of mass spectrometry (MS) and nuclear magnetic resonance (NMR) which yielded 495 and 26 metabolite measurements respectively. The plasma samples came from a cross-sectional set of young SV subjects, ages 2-19 years with ten control (Con) subjects and 16 SV subjects. Of the SV subjects, nine were diagnosed as congestive HF (SVHF), and 7 were not in HF. Metabolomic data were correlated with clinical status to determine if there was a signature associated with HF. Results: There were no differences in age, height, weight or sex between the 3 cohorts. However, statistical analysis of the metabolomic profiles using ANOVA revealed 44 metabolites with significant differences between cohorts including 41 profiled by MS and 3 by NMR. These metabolites included acylcarnitines, amino acids, and bile acids, which distinguished Con from all SV subjects. Furthermore, metabolite profiles could distinguish between SV and SVHF subjects. Conclusion: These are the first data to demonstrate a clear metabolomic signature associated with HF in children and young adults with SV. Larger studies are warranted to determine if these findings are predictive of progression to HF in time to provide intervention.