The C-Terminal Cross-linked Telopeptide of Type I Collagen (CTX-I) as a Potential Cardiomyopathy Biomarker in Friedreich Ataxia Patients

Chiara Pane, Assunta Trinchillo, Andrea Salzano, Angela Marsili, Giorgia Puorro, Antonio Cittadini, Francesco Saccà & Cinzia Valeria Russo; Cerebellum (2022). doi:10.1007/s12311-022-01475-4 

CTX-I, a biomarkers of collagen turnover, is elevated in FRDA and should provide complementary information to identify patients with high cardiological risk even if longitudinal studies are needed to define the role of this serologic marker of collagen metabolism in the natural history of cardiomyopathy in FRDA patients.

A non-synonymous single nucleotide polymorphism in SIRT6 predicts neurological severity in Friedreich ataxia

Rodden LN, Rummey C, Dong YN, Lagedrost S, Regner S, Brocht A, Bushara K, Delatycki MB, Gomez CM, Mathews K, Murray S, Perlman S, Ravina B, Subramony SH, Wilmot G, Zesiewicz T, Bolotta A, Domissy A, Jespersen C, Ji B, Soragni E, Gottesfeld JM and Lynch DR; (2022). Front. Mol. Biosci. 9:933788. doi: 10.3389/fmolb.2022.933788

People with FRDA in the CT SIRT6 group have less severe neurological and visual dysfunction than those in the TT SIRT6 group. Biochemical analyses indicate that the benefit conferred by T to C SNP in SIRT6 does not come from altered expression or enzymatic activity of SIRT6 or frataxin but is associated with changes in the transcriptome.

Hyperactivation of mTOR and AKT in a cardiac hypertrophy animal model of Friedreich ataxia

Wing-Hang Tong, Hayden Ollivierre, Audrey Noguchi, Manik C. Ghosh, Danielle A. Springer, Tracey A. Rouault; Heliyon, Volume 8, Issue 8, 2022. 

 We observed increased phosphorylation of AKT and dysregulation of multiple downstream effectors of mTORC1, including S6K1, S6, ULK1 and 4EBP1, in a cardiac/skeletal muscle specific FRDA conditional knockout (cKO) mouse model and in human cell lines depleted of ISC biogenesis factors.

Respiratory Function in Friedreich’s Ataxia

Vinante, E.; Colombo, E.; Paparella, G.; Martinuzzi, M.; Martinuzzi, A. Children 2022, 9, 1319. https://doi.org/10.3390/children9091319

Respiratory function is impaired at various degrees in FRDA. The complex condition of inco-ordination and hyposthenia in FRDA affects daytime and night-time respiratory efficiency. We believe that the respiratory deficit and the inefficiency of cough are indeed a clinical problem deserving consideration, especially in the context of the concomitant postural difficulty and the possible presence of dysphagia. Therefore, the rehabilitation project for the subject with FRDA should also consider the respiratory function.

Preservation of bioenergetics and inhibition of ferroptosis with the novel compound SBT-588 in Friedreich’s ataxia cell models

Laura E. Kropp, Hatim Zariwala, Yunmi Park, Martin Redmon, David A. Brown, Alyssa Handler; Biochimica et Biophysica Acta (BBA) - Bioenergetics, Volume 1863, Supplement, 2022, doi:10.1016/j.bbabio.2022.148869.

Frataxin deficiency disrupts mitochondrial respiration and pulmonary endothelial cell function

Miranda K Culley, Monica Mehta, Jingsi Zhao, Dror Perk, Yi Yin Tai, Ying Tang, Sruti Shiva, Marlene Rabinovitch, Mingxia Gu, Thomas Bertero, Stephen Y Chan; bioRxiv 2022.08.22.504849; doi:org/10.1101/2022.08.22.504849

Our data highlight an Fe-S-driven metabolic shift separate from previously described replication stress whereby FXN knockdown diminished mitochondrial respiration and increased glycolysis and oxidative species production. In turn, FXN-deficient endothelial cells exhibited a vasoconstrictive phenotype consistent with PH. These data were observed in both primary pulmonary endothelial cells after pharmacologic inhibition of FXN and inducible pluripotent stem cell-derived endothelial cells from patients with FXN mutations. Altogether, this study defines FXN as a shared upstream driver of pathologic aberrations in both metabolism and genomic stability. Moreover, our study highlights FXN-specific vasoconstriction, suggesting available and future therapies may be beneficial and targeted for PH subtypes with FXN deficiency.

A systematic review of disease prevalence, health-related quality of life, and economic outcomes associated with Friedreich’s Ataxia

Katherine Buesch & Rongrong Zhang (2022) , Current Medical Research and Opinion, DOI: 10.1080/03007995.2022.2112870 

Findings from this systematic review revealed several knowledge gaps that would preclude the conduct of a robust assessment of the benefits and outcomes associated with a disease-modifying FA therapy. Additional understanding regarding patient and caregiver HRQoL and costs is required.

Direct utility of natural history data in analysis of clinical trials: Propensity match-based analysis of Omaveloxolone in Friedreich ataxia using the FA-COMS dataset

David Lynch, Angie Goldsberry, Christian Rummey, Jennifer Farmer, Sylvia Boesch, martin delatycki, Paola Giunti, j chad Hoyle, Caterina Mariotti, Katherine Mathews, Susan Perlman, SH Subramony, George Wilmot, Theresa Zesiwiecz, Lisa Weissfeld, Colin Meyer medRxiv 2022.08.12.22278684; doi: 10.1101/2022.08.12.22278684 

These results suggest a clinically meaningful slowing of FRDA progression with omaveloxolone, and consequently details how propensity-matched analysis contributes to the understanding of the effects of therapeutic agents. This demonstrates the direct value of natural history studies in the evaluation of clinical trials.

Replication dependent and independent mechanisms of GAA repeat instability

Chiara Masnovo, Ayesha F. Lobo, Sergei M. Mirkin; DNA Repair, Volume 118, 2022, 103385, doi:10.1016/j.dnarep.2022.103385. 

Here, we provide a brief historical overview on the discovery of (GAA)n repeat expansions and their association to FRDA, followed by recent advances in the identification of triplex H-DNA formation and replication fork stalling. The main body of this review focuses on the last decade of progress in understanding the mechanism of (GAA)n repeat instability during DNA replication and/or DNA repair. We propose that the discovery of additional mechanisms of (GAA)n repeat instability can be achieved via both comparative approaches to other repeat expansion diseases and genome-wide association studies. Finally, we discuss the advances towards FRDA prevention or amelioration that specifically target (GAA)n repeat expansions.

An open-label pilot study of recombinant granulocyte-colony stimulating factor in Friedreich’s ataxia

Kevin C. Kemp, Anastasia Georgievskaya, Kelly Hares, Juliana Redondo, Steven Bailey, Claire M. Rice, Neil J. Scolding, Chris Metcalfe & Alastair Wilkins; Nat Commun 13, 4655 (2022). doi:10.1038/s41467-022-31450-w 

 Pharmacological interventions to increase frataxin expression and reverse the deleterious effects of frataxin deficiency are attractive therapeutic approaches in FA. We have shown that a course of G-CSF therapy in participants with FA is safe, is associated with effective HSC mobilisation, and leads to significant elevations in frataxin together with improvements in biochemical deficits associated with FA. Nevertheless, the need for future assessment of G-CSF administration on affected tissues, such as the heart and brain, using a range of dose levels and dosing frequencies is required. The long-term safety of sustained G-CSF administration in people with FA is also unknown. The natural rate of disease progression in FA necessitates prolonged trial periods to sufficiently detect changes in clinical measures. This study provides proof-of-principle evidence to support an efficacy study of G-CSF administration in FA, using repeated courses over a longer period.

 

An open-label pilot study of recombinant granulocyte-colony stimulating factor in Friedreich’s ataxia