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Friedreich ataxia (FRDA) is a multisystemic, autosomal recessive disorder caused by homozygous GAA expansion mutation in the first intron of frataxin ( FXN ) gene. FXN is a mitochondrial protein critical for iron-sulfur cluster biosynthesis and deficiency impairs mitochondrial electron transport chain functions and iron homeostasis within the organelle. Currently, there is no effective treatment for FRDA. We have previously demonstrated that single infusion of wild-type hematopoietic stem and progenitor cells (HSPCs) resulted in prevention of neurologic and cardiac complications of FRDA in YG8R mice, and rescue was mediated by FXN transfer from tissue engrafted, HSPC-derived microglia/macrophages to diseased neurons/myocytes. For a future clinical translation, we developed an autologous stem cell transplantation approach using CRISPR/Cas9 for the excision of the GAA repeats in FRDA patients' CD34 + HSPCs; this strategy leading to increased FXN expression and improved mitochondrial functions. The aim of the current study is to validate the efficiency and safety of our gene editing approach in a disease-relevant model. We generated a cohort of FRDA patient-derived iPSCs and isogenic lines that were gene edited with our CRISPR/Cas9 approach. iPSC derived FRDA neurons displayed characteristic apoptotic and mitochondrial phenotype of the disease, such as non-homogenous microtubule staining in neurites, increased caspase-3 expression, mitochondrial superoxide levels, mitochondrial fragmentation, and partial degradation of the cristae compared to healthy controls. These defects were fully prevented in the gene edited neurons. RNASeq analysis of FRDA and gene edited neurons demonstrated striking improvement in gene clusters associated with endoplasmic reticulum (ER) stress in the isogenic lines. Gene edited neurons demonstrated improved ER-calcium release, normalization of ER stress response gene, XBP-1, and significantly increased ER-mitochondrial contacts that are critical for functional homeostasis of both organelles, as compared to FRDA neurons. Ultrastructural analysis for these contact sites displayed severe ER structural damage in FRDA neurons, that was undetected in gene edited neurons. Taken together, these results represent a novel finding for disease pathogenesis showing dramatic ER structural damage in FRDA, validate the efficacy profile of our FXN gene editing approach in a disease relevant model, and support our approach as an effective strategy for therapeutic intervention for Friedreich's ataxia., Competing Interests: SC is a cofounder, shareholder, and a member of both the Scientific Board and board of directors of Papillon Therapeutics Inc. SC also serves as a member of the Scientific Review Board and Board of Trustees of the Cystinosis Research Foundation. This work is covered in the patent entitled “Methods for treating Mitochondrial Disorders” (#114198-3029). The terms of this arrangement have been reviewed and approved by the University of California San Diego in accordance with its conflict-of-interest policies. The remaining authors declare that the research was conducted in the absence of any commercial of financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Mishra, Sivakumar, Johnson, Pernaci, Warden, El-Hachem, Hansen, Badell-Grau, Khare, Ramirez, Gillette, Solis, Guo, Coufal and Cherqui.)

Statins are important in the prevention of cardiovascular (CV) disease. However, they are associated with new-onset diabetes in a dose-dependent manner, particularly when the patient is already in risk of contracting diabetes. Meta-analyses estimate that the risk is increased by 9%. In absolute terms one major CV event can be prevented per 155 patients treated with statins per year compared to one new case of diabetes per 498 patients treated per year. However, this new evidence should not affect the guidelines, where the goal of LDL-cholesterol concentration is < 1,8 mmol/l in patients with high CV risk.

Statins are potent inhibitors of cholesterol biosynthesis. Statins are beneficial in the primary and secondary prevention of coronary heart disease. Recent studies indicate that there is an association between statin use and the development of new-onset diabetes mellitus. This article reviews the patophysiological mechanisms by different statins to explain this association.