The Nitric Oxide Donor, S-Nitrosoglutathione, Rescues Peroxisome Number and Activity Defects in PEX1G843D Mild Zellweger Syndrome Fibroblasts.

Yidi Liu,Richard A Rachubinski,Lilliana Linchieh,Yarina Sen,Ceileigh M Weaver,Olivier Lurette,Gary Eitzen,Francesca Di Cara,Etienne Hebert-Chatelain,Andrew J Simmonds

doi:10.3389/fcell.2021.714710

Abstract

Peroxisome biogenesis disorders (PBDs) are a group of metabolic developmental diseases caused by mutations in one or more genes encoding peroxisomal proteins. Zellweger syndrome spectrum (PBD-ZSS) results from metabolic dysfunction caused by damaged or non-functional peroxisomes and manifests as a multi-organ syndrome with significant morbidity and mortality for which there is no current drug therapy. Mild PBD-ZSS patients can exhibit a more progressive disease course and could benefit from the identification of drugs to improve the quality of life and extend the lifespan of affected individuals. Our study used a high-throughput screen of FDA-approved compounds to identify compounds that improve peroxisome function and biogenesis in human fibroblast cells carrying the mild PBD-ZSS variant, PEX1G843D. Our screen identified the nitrogen oxide donor, S-nitrosoglutathione (GSNO), as a potential therapeutic for this mild form of PBD-ZSS. Further biochemical characterization showed that GSNO enhances both peroxisome number and function in PEX1G843D mutant fibroblasts and leads to increased survival and longer lifespan in an in vivo humanized Drosophila model carrying the PEX1G843D mutation. GSNO is therefore a strong candidate to be translated to clinical trials as a potential therapeutic for mild PBD-ZSS.

Highlights

Peroxisomes are cellular organelles present in almost every eukaryotic cell and are the site of essential metabolic reactions for organismal development and survival
Our work demonstrated that S-nitrosoglutathione (GSNO), a nitric oxide (NO) donor that is regarded as an intracellular NO reservoir and as a vehicle for NO throughout the cell (Corpas et al, 2013), increases peroxisome numbers in PEX1G843D mutant fibroblasts, improves the overall biochemical activities associated with peroxisomes in these mutant fibroblasts, and increases the survival and extends the lifespan of humanized flies with the PEX1G843D mutation, thereby opening up the possibility of developing GSNO into a clinical therapy for mild peroxisome biogenesis disorder (PBD)-ZSS patients
Indirect IF microscopy analyses revealed that only treatment with T6, the nitric oxide donor GSNO (Stolz et al, 2002; Corpas et al, 2013, 2017, 2021), reproducibly increased the number of SKL-positive puncta in PEX1G843D fibroblasts almost to numbers observed in WT fibroblasts (Figures 1B,C and Supplementary Figure 1A)

Summary

Introduction

Peroxisomes are cellular organelles present in almost every eukaryotic cell and are the site of essential metabolic reactions for organismal development and survival. Matrix enzymes within the peroxisome metabolize reactive oxygen and nitrogen species and catalyze the β-oxidation of very-long chain fatty acids (VLCFAs), synthesis of ether lipids, and processing of other complex. GSNO Improves Zellweger Peroxisome Function lipids (Wanders and Waterham, 2006). Mutations in the genes encoding PEX proteins impair peroxisome biogenesis and function, and underlie a clinical spectrum of disorders known as the Peroxisome Biogenesis Disorders (PBDs). PBDs are divided into two distinct syndromes: Zellweger syndrome spectrum (PBD-ZSS) and Rhizomelic Chondrodysplasia Punctata spectrum (PBD-RCDP). With the exception of the PEX7 mutation underlying most cases of PBD-RCDP, most other PEX gene mutations result in generalized peroxisome dysfunction and the PBD-ZSS phenotype (Braverman et al, 2013)

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