Duchenne's muscular dystrophy involves a defective transsulfuration pathway activity

Abstract

Duchenne muscular dystrophy (DMD) is the most frequent X chromosome-linked disease caused by mutations in the gene encoding for dystrophin, leading to progressive and unstoppable degeneration of skeletal muscle tissues. Despite recent advances in the understanding of the molecular processes involved in the pathogenesis of DMD, there is still no cure. In this study, we aim at investigating the potential involvement of the transsulfuration pathway (TSP), and its by-end product namely hydrogen sulfide (H 2 S), in primary human myoblasts isolated from DMD donors and skeletal muscles of dystrophic ( mdx ) mice. In myoblasts of DMD donors, we demonstrate that the expression of key genes regulating the H 2 S production and TSP activity, including cystathionine γ lyase (CSE), cystathionine beta-synthase (CBS), 3 mercaptopyruvate sulfurtransferase (3-MST), cysteine dioxygenase (CDO), cysteine sulfonic acid decarboxylase (CSAD), glutathione synthase (GS) and γ -glutamylcysteine synthetase (γ-GCS) is reduced. Starting from these findings, using Nuclear Magnetic Resonance (NMR) and quantitative Polymerase Chain Reaction (qPCR) we show that the levels of TSP-related metabolites such as methionine, glycine, glutathione, glutamate and taurine, as well as the expression levels of the aforementioned TSP related genes, are significantly reduced in skeletal muscles of mdx mice compared to healthy controls, at both an early (7 weeks) and overt (17 weeks) stage of the disease. Importantly, the treatment with sodium hydrosulfide (NaHS), a commonly used H 2 S donor, fully recovers the impaired locomotor activity in both 7 and 17 old mdx mice. This is an effect attributable to the reduced expression of pro-inflammatory markers and restoration of autophagy in skeletal muscle tissues. In conclusion, our study uncovers a defective TSP pathway activity in DMD and highlights the role of H 2 S-donors for novel and safe adjuvant therapy to treat symptoms of DMD.

Dysregulated Autophagy and Mitophagy in a Mouse Model of Duchenne Muscular Dystrophy Remain Unchanged Following Heme Oxygenase-1 Knockout

“…We noted a decrease in the expression of Atg5 , Atg7 , Becn1 , Map1lc3b , Lamp1 , and Sqstm1 genes in the gastrocnemius muscle, but in the diaphragm of 6-week-old mice, only Map1lc3b was reduced. Similarly to our study, Panza et al reported diminished expression of among others, Lamp1, Becn1 , and Atg7 , in quadriceps of 7-week-old animals [ 16 ] and the expression of Becn1, Map1lc3b, Lamp1 , and Sqstm1 was decreased in the same muscle of 22-week-old mice [ 11 ]. No difference in the mRNA levels of the Map1lc3a , Map1lc3b , and Sqstm1 genes was found between WT and mdx mice hearts [ 8 ].…”

“…Interestingly, Whitehead et al noted that the use of simvastatin (an HMG-CoA reductase inhibitor, generally used to normalize cholesterol levels) has a positive effect on autophagy in the DMD mouse model [ 14 , 15 ]. Recently, restoration of functional autophagy in dystrophic skeletal muscle was also observed after treatment with a hydrogen sulfide donor [ 16 ]. Of note, it was also underlined that expression of mitophagy- and autophagy-related proteins may vary during mice lifetime [ 17 ].…”

Beneficial Effect of H2S-Releasing Molecules in an In Vitro Model of Sarcopenia: Relevance of Glucoraphanin

“…In this scenario, H 2 S may offer new pharmacological approaches for the management of sarcopenia. Indeed, it is well accepted the role of H 2 S in the physiopathology of SKM [ 14 , 20 , 27 ] but also in the pathogenesis of diabetes [ 50 ] and not last as an important mediator of inflammation [ 51 , 52 , 53 ]. Considering this evidence, we assessed the efficacy of endogenous or exogenous sources of H 2 S in an in vitro model of sarcopenia.…”

“…This evidence is reinforced by Terrill and colleagues, who observed a decrease in dystropathology and oxidative stress in L-cysteine-treated mdx mice [ 26 ]. More recent evidence demonstrates that, in myoblasts of DMD patients, there is an impairment in H 2 S signalling; indeed, a lowering in the gene expression of the CBS and CSE and H 2 S production was found [ 27 ]. Importantly, the exogenous replacement of H 2 S improves the molecular features of DMD in terms of inflammation and fibrosis in mdx mice [ 27 ].…”

Progress and perspective on hydrogen sulfide donors and their biomedical applications

“…The sulfide salts could boost the local concentration of H 2 S in a short time, and they are considered as relative “clean” H 2 S donors due to no byproduct formation after H 2 S release. As a consequence, they are employed in a broad range of biological studies and exert beneficial pharmacological effects on central nervous system, cardiovascular system, alimentary system, male reproductive system, and many other related systems through a wide range of mechanisms 119,121,129–132 . However, due to the instantaneous H 2 S release characteristic of NaHS and Na 2 S, the desired release of H 2 S at a controlled rate within a long‐term period of time to specific organs, which mimics the endogenous H 2 S production, fails 118,119 .…”