Identification of drug modifiers for RYR1 related myopathy using a multi-species discovery pipeline
- The Hospital for Sick Children, Canada
- University of Toronto, Canada
- University of Rochester, United States
- University of North Carolina at Chapel Hill, United States
- University of Rochester School of Medicine and Dentistry, United States
Abstract
Ryanodine receptor type I-related myopathies (RYR1-RMs) are a common group of childhood muscle diseases associated with severe disabilities and early mortality for which there are no available treatments. The goal of this study is to identify new therapeutic targets for RYR1-RMs. To accomplish this, we developed a discovery pipeline using nematode, zebrafish, and mammalian cell models. We first performed large-scale drug screens in C. elegans which uncovered 74 hits. Targeted testing in zebrafish yielded positive results for two p38 inhibitors. Using mouse myotubes, we found that either pharmacological inhibition or siRNA silencing of p38 impaired caffeine-induced Ca2+ release from wild type cells while promoting intracellular Ca2+ release in Ryr1 knockout cells. Lastly, we demonstrated that p38 inhibition blunts the aberrant temperature-dependent increase in resting Ca2+ in myotubes from an RYR1-RM mouse model. This unique platform for RYR1-RM therapy development is potentially applicable to a broad range of neuromuscular disorders.
Data availability
All data generated or analysed during this study are included in the manuscript and supporting files. Source files are available for all figures.
Article and author information
Author details
Funding
Muscular Dystrophy Association
- Robert T Dirksen
- James J Dowling
RYR1 Foundation
- Robert T Dirksen
- James J Dowling
Canadian Institutes of Health Research (363863)
- Robert T Dirksen
- James J Dowling
The funders had no role in study design, data collection and interpretation, or the decision to submit the work for publication.
Ethics
Animal experimentation: All zebrafish experiments were performed in accordance with all relevant ethical regulations, specifically following the policies and guidelines of the Canadian Council on Animal Care and an institutionally reviewed and approved animal use protocol (#41617). No additional ethical approval was required for our experiments with the invertebrate nematode worm C. elegans.
Copyright
© 2020, Volpatti et al.
This article is distributed under the terms of the Creative Commons Attribution License permitting unrestricted use and redistribution provided that the original author and source are credited.
Metrics
-
- 2,308
- views
-
- 276
- downloads
-
- 19
- citations
Views, downloads and citations are aggregated across all versions of this paper published by eLife.
Download links
A two-part list of links to download the article, or parts of the article, in various formats.
Downloads (link to download the article as PDF)
Open citations (links to open the citations from this article in various online reference manager services)
Cite this article (links to download the citations from this article in formats compatible with various reference manager tools)
Identification of drug modifiers for RYR1 related myopathy using a multi-species discovery pipeline
eLife 9:e52946.
https://doi.org/10.7554/eLife.52946
Further reading
-
- Cell Biology
- Medicine
Disturbed shear stress-induced endothelial atherogenic responses are pivotal in the initiation and progression of atherosclerosis, contributing to the uneven distribution of atherosclerotic lesions. This study investigates the role of Aff3ir-ORF2, a novel nested gene variant, in disturbed flow-induced endothelial cell activation and atherosclerosis. We demonstrate that disturbed shear stress significantly reduces Aff3ir-ORF2 expression in athero-prone regions. Using three distinct mouse models with manipulated Aff3ir-ORF2 expression, we demonstrate that Aff3ir-ORF2 exerts potent anti-inflammatory and anti-atherosclerotic effects in Apoe-/- mice. RNA sequencing revealed that interferon regulatory factor 5 (Irf5), a key regulator of inflammatory processes, mediates inflammatory responses associated with Aff3ir-ORF2 deficiency. Aff3ir-ORF2 interacts with Irf5, promoting its retention in the cytoplasm, thereby inhibiting the Irf5-dependent inflammatory pathways. Notably, Irf5 knockdown in Aff3ir-ORF2 deficient mice almost completely rescues the aggravated atherosclerotic phenotype. Moreover, endothelial-specific Aff3ir-ORF2 supplementation using the CRISPR/Cas9 system significantly ameliorated endothelial activation and atherosclerosis. These findings elucidate a novel role for Aff3ir-ORF2 in mitigating endothelial inflammation and atherosclerosis by acting as an inhibitor of Irf5, highlighting its potential as a valuable therapeutic approach for treating atherosclerosis.
-
- Medicine
- Neuroscience
Monomethyl fumarate (MMF) and its prodrug dimethyl fumarate (DMF) are currently the most widely used agents for the treatment of multiple sclerosis (MS). However, not all patients benefit from DMF. We hypothesized that the variable response of patients may be due to their diet. In support of this hypothesis, mice subjected to experimental autoimmune encephalomyelitis (EAE), a model of MS, did not benefit from DMF treatment when fed a lauric acid-rich (LA) diet. Mice on normal chow (NC) diet, in contrast, and even more so mice on high-fiber (HFb) diet showed the expected protective DMF effect. DMF lacked efficacy in the LA diet-fed group despite similar resorption and preserved effects on plasma lipids. When mice were fed the permissive HFb diet, the protective effect of DMF treatment depended on hydroxycarboxylic receptor 2 (HCAR2) which is highly expressed in neutrophil granulocytes. Indeed, deletion of Hcar2 in neutrophils abrogated DMF protective effects in EAE. Diet had a profound effect on the transcriptional profile of neutrophils and modulated their response to MMF. In summary, DMF required HCAR2 on neutrophils as well as permissive dietary effects for its therapeutic action. Translating the dietary intervention into the clinic may improve MS therapy.
