Biochemical alterations precede neurobehavioral deficits in a novel mouse model of Friedreich ataxia

Marta Medina-Carbonero, Arabela Sanz-Alcazar, Elena Britti, Fabien Delaspre, Elisa Cabiscol, Joaquim Ros, Jordi Tamarit; bioRxiv 2021.04.05.438486; doi: doi:10.1101/2021.04.05.438486 

In the present work, we have characterized a new mouse model of FA (FXNI151F) based on a pathological point mutation (I154F) present in some FA patients. These mice present very low frataxin levels in all tissues and display neurological deficits resembling those observed in FA patients. We have also observed decreased content of components from OXPHOS complexes I and II, decreased aconitase activity, and alterations in the antioxidant defenses. Remarkably, these biochemical alterations precede the appearance of neurological symptoms and present a different profile in heart and brain or cerebellum. The FXNI151F mouse is an excellent tool for analyzing the consequences of frataxin deficiency in different tissues and for testing new therapies.

Synthesis of 5‐[(1H‐indol‐3‐yl)methyl]‐1,3,4‐oxadiazole‐2(3H)‐thiones and their protective activity against oxidative stress

škauskienė, M., Kadlecová, A., Voller, J., Janovská, L., Malinauskienė, V., Žukauskaitė, A., Šačkus, A., Arch. Pharm. 2021, e2100001. doi:10.1002/ardp.202100001

A series of 5‐[(1H‐indol‐3‐yl)methyl]‐1,3,4‐oxadiazole‐2(3H)‐thiones was synthesized in this study. Methyl substitution on the indole ring and propyl, butyl, or benzyl substitution on sulfhydryl group‐possessing compounds were revealed to protect Friedreich's ataxia fibroblasts against chemically induced oxidative stress. Two of the active compounds also reproducibly increased the survival of Caenorhabditis elegans exposed to juglone‐induced oxidative stress.

Lessons for clinical trial design in Friedreich's ataxia

Masha G Savelieff Eva L Feldman The Lancet Neurology; Published:March 23, 2021DOI:https://doi.org/10.1016/S1474-4422(21)00064-8 Friedreich's ataxia is a rare autosomal-recessive disease caused by mutations in the FXN gene, which encodes frataxin, a mitochondrial protein.  It is the most common inherited ataxia, which usually manifests as gait unsteadiness in adolescence, with slowly progressive trunk and limb ataxia, and eventual loss of independent movement.  Friedreich's ataxia often involves the heart and musculoskeletal system and raises diabetes risk, making it a multisystem disorder.

Rare-disease researchers face unique obstacles: Minoryx

29-Mar-2021 By Jenni Spinner A representative of the rare-disease specialist firm outlines the unique obstacles of orphan CNS disease research, and how professionals can overcome them.

Mapa epidemiológico transversal de las ataxias y paraparesias espásticas hereditarias en EspañaEpidemiology of ataxia and hereditary spastic paraplegia in Spain: a cross-sectional study

G. Ortega Suero, M.J. Abenza Abildúa, C. Serrano Munuera, I. Rouco Axpe, F.J. Arpa Gutiérrez, A.D. Adarmes Gómez, F.J. Rodríguez de Rivera, B. Quintans Castro, I. Posada Rodríguez, A. Vadillo Bermejo, Á. Domingo Santos, E. Blanco Vicente, I. Infante Ceberio, J. Pardo Fernández, E. Costa Arpín, C. Painous Martí, J.E. Muñoz, P. Mir Rivera, F. Montón Álvarez, L. Bataller Alberola, J. Gascón Bayarri, C. Casasnovas Pons, V. Vélez Santamaría, A. López Munain, G. Fernández García Eulate, J. Gazulla Abío, I. Sanz Gallego, L. Rojas Bartolomé, Ó. Ayo Martín, T. Segura Martín, C. González Mingot, M. Baraldés Rovira, R. Sivera Mascaró, E. Cubo Delgado, A. Echevarría Íñiguez, F. Vázquez Sánchez, M. Bártulos Iglesias, M.T. Casadevall Codina, E.M. Martínez Fernández, C. Labandeira Guerra, B. Alemany Perna, A. Carvajal Hernández, C. Fernández Moreno, M. Palacín Larroy, N. Caballol Pons, A. Ávila Rivera, F.J. Navacerrada Barrero, R. Lobato Rodríguez, M.J. Sobrido Gómez; Neurología, 2021, doi:10.1016/j.nrl.2021.01.006. 

 We conducted a cross-sectional, multicentre, retrospective, descriptive study of patients with ataxia and hereditary spastic paraplegia in Spain between March 2018 and December 2019. Mean (SD) age in our sample was 53.64 (20.51) years; 920 patients were men (50.8%) and 889 were women (49.2%). The genetic defect was unidentified in 920 patients (47.6%). A total of 1371 patients (70.9%) had ataxia and 562 (29.1%) had hereditary spastic paraplegia. Prevalence rates for ataxia and hereditary spastic paraplegia were estimated at 5.48 and 2.24 cases per 100 000 population, respectively. The most frequent type of dominant ataxia in our sample was SCA3, and the most frequent recessive ataxia was Friedreich ataxia. 

Pre-clinical left ventricular myocardial remodeling in patients with Friedreich's ataxia: A cardiac MRI study

Takazaki KAG, Quinaglia T, Venancio TD, Martinez ARM, Shah RV, Neilan TG, Jerosch-Herold M, Coelho-Filho OR, França MC Jr.; PLoS One. 2021 Mar 26;16(3):e0246633. doi: 10.1371/journal.pone.0246633. LV hypertrophy and concentric LV remodeling in FRDA are associated at the tissue level with an expansion of the ECV and an increase in cardiomyocyte size. The adverse tissue remodeling assessed by ECV and τic is associated with more severe cardiomyopathy classification, suggesting a role for these markers in tracking disease progression. 

Quantitative assessment of Friedreich Ataxia via self-drinking activity

Ragil Krishna, Pubudu N Pathirana, Malcolm Horne, Louise Corben, David Szmulewicz; IEEE J Biomed Health Inform. 2021 Mar 25;PP. doi: 10.1109/JBHI.2021.3069007.

In this study, we propose an ataxia measuring device, in the form of a pressure canister capable of sensing certain kinetic and kinematic parameters of interest to quantify the impairment levels of participants particularly when engaged in an activity that is closely associated with daily living. In particular, the functional task of simulated drinking was utilised to capture characteristic features of disability manifestation in terms of diagnosis (separation of individuals with FA and controls) and severity assessment of individuals diagnosed with the debilitating condition of FA. Time and frequency domain analysis of these biomarkers enabled the classification of individuals with FA and control subjects to reach an accuracy of 98\% and a correlation level reaching 96\% with the clinical scores. 

NAD+ Precursor Supplementation in Friedreich's Ataxia

ClinicalTrials.gov Identifier: NCT04817111. A Phase 2a Study of NAD+ Precursor Supplementation in Friedreich's Ataxia 

Sponsor: Metro International Biotech, LLC; Collaborator: Children's Hospital of Philadelphia

Detailed Description: The primary focus for this protocol is safety and tolerability. We will systematically assess for adverse events using a safety monitoring uniform report form. We will also use cardiac 31-Phosphorus-Magnetic Resonance Spectroscopy (MRS) to measure the Phosphocreatine(PCr)/Adenosine triphosphate (ATP)- γ ratio before and after treatment with MIB-626. In addition, if time permits we will use proton (1H)-MRS to measure skeletal muscle nicotinamide adenine dinucleotide (NAD+) before and after treatment.

A severe form of autosomal recessive spinocerebellar ataxia associated with novel PMPCA variants

Yoko Takahashi, Masaya Kubota, Rika Kosaki, Kenjiro Kosaki, Akira Ishiguro; Brain and Development, Volume 43, Issue 3, 2021, Pages 464-469, doi:10.1016/j.braindev.2020.11.008. 

Spinocerebellar ataxia, autosomal recessive 2 (SCAR2) [MIM:213200] is a rare autosomal recessive disease of spinocerebellar ataxia associated with degeneration of the cerebellum with variable involvement of the brainstem and spinal cord. SCAR2 is characterized by onset of impaired motor development and ataxic gait in early childhood. Recently, several PMPCA gene variants have been reported in SCAR2 patients with mild and non-progressive symptoms. PMPCA codes frataxin, which is crucial for iron biosynthesis in cells. 

**Evidences showed that MPP ( Mitochondrial-processing peptidase subunit alpha) is an enzyme that in humans is encoded by the PMPCA gene, it's involved in the proteolytic maturation of Frataxin, a protein responsible for iron homeostasis. Accordingly, MPP deficiency was shown to be involved in Friedreich ataxia, an autossomic recessive neurodegenerative disorder.

Progression characteristics of the European Friedreich's Ataxia Consortium for Translational Studies (EFACTS): a 4-year cohort study

Prof Kathrin Reetz, MD, Imis Dogan, PhD, Prof Ralf-Dieter Hilgers, PhD, Prof Paola Giunti, MD, Michael H Parkinson, MBBS, Caterina Mariotti, MD, Lorenzo Nanetti, MD, Prof Alexandra Durr, MD, Claire Ewenczyk, MD, Sylvia Boesch, MDWolfgang Nachbauer, MD, Thomas Klopstock, MD,, Claudia Stendel, MD, Francisco Javier Rodríguez de Rivera Garrido, MD, Christian Rummey, PhD, Prof Ludger Schöls, MD, Stefanie N Hayer, PhD Prof Thomas Klockgether, MD, Ilaria Giordano, MD, Claire Didszun, PhD, Myriam Rai, PhD, Prof Massimo Pandolfo, MD, Prof Jörg B Schulz on behalf of theEFACTS study group; The Lancet Neurology, Published:March 23, 2021 DOI:10.1016/S1474-4422(21)00027-2 

The European Friedreich's Ataxia Consortium for Translational Studies (EFACTS) investigates the natural history of Friedreich's ataxia. We aimed to assess progression characteristics and to identify patient groups with differential progression rates based on longitudinal 4-year data to inform upcoming clinical trials in Friedreich's ataxia.