Search bioRxiv⌕ Search
Home/Archive/bioRxiv

bioRxiv · 10.1101/2023.05.17.541238

MuSK-BMP signaling in adult muscle stem cells maintains quiescence and regulates myofiber size

Madigan, L. A.·Jaime, D.·Fallon, J. R.
View original source ↗Export metadata ↓

Abstract

A central question in adult stem cell biology is elucidating the signaling pathways regulating their dynamics and function in diverse physiological and age-related contexts. Muscle stem cells in adults (Satellite Cells; SCs) are generally quiescent but can activate and contribute to muscle repair and growth. Here we tested the role of the MuSK-BMP pathway in regulating adult SC quiescence by deletion of the BMP-binding MuSK Ig3 domain ( {Delta}Ig3-MuSK). At 3 months of age SC and myonuclei numbers and myofiber size were comparable to WT. However, at 5 months of age SC density was decreased while myofiber size, myonuclear number and grip strength were increased - indicating that SCs had activated and productively fused into the myofibers over this interval. Transcriptomic analysis showed that SCs from uninjured {Delta}Ig3-MuSK mice exhibit signatures of activation. Regeneration experiments showed that {Delta}Ig3-MuSK SCs maintain full stem cell function. Expression of {Delta}Ig3-MuSK in adult SCs was sufficient to break quiescence and increase myofiber size. We conclude that the MuSK-BMP pathway regulates SC quiescence and myofiber size in a cell autonomous, age-dependent manner. Targeting MuSK-BMP signaling in muscle stem cells thus emerges a therapeutic strategy for promoting muscle growth and function in the settings of injury, disease, and aging. HighlightsO_LIMuSK, in its role as a BMP co-receptor, regulates adult muscle stem cell quiescence C_LIO_LIThe MuSK-BMP pathway acts cell autonomously C_LIO_LIIncreased muscle size and function with preservation of myonuclear density and stemness in mice with attenuated MuSK-BMP signaling C_LI

Explore related subjects

cell biologyPreprint

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

Madigan, L. A., Jaime, D., Fallon, J. R.. 2023-05-18. MuSK-BMP signaling in adult muscle stem cells maintains quiescence and regulates myofiber size. https://doi.org/10.1101/2023.05.17.541238

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related preprints

bioRxiv2026

RCDome: A Multi-Database Human Gene Atlas of Regulated Cell Death

Introduction: Regulated cell death (RCD) governs tissue homeostasis, development, and disease, and is executed or regulated by specific genes. Yet for the researcher asking which genes execute or regulate a given RCD form, the answer is rarely simple: gene lists for the same form rarely agree across databases, many associations carry no traceable source, and most have never been systematically checked against primary literature. We built RCDome to answer the most basic question a researcher can ask: where did this gene-RCD association come from, and what is the evidence? Methods: RCDome is a multi-database human gene atlas built through a staged architecture integrating multi-source compilation, literature validation and evidence recovery, mechanistic classification, human-governed ontological adjudication, and web deployment. Five complementary evidence channels (PubMed Boolean search, curated databases, AI-assisted screening, manual curation, and Elicit systematic review) were integrated from 20 public databases into a unified matrix. Sixty-two original name strings were canonicalized into 53 RCD-related entities with curator-adjudicated operational definitions and ontological levels. Gene-RCD associations were systematically evaluated through an independent DeepSeek two-call LLM validation, Europe PMC full-text recovery and deep evidence extraction, an independent Consensus literature-search channel, and GPT-4o arbitration of disagreements. Source-grounding controls rejected extracted evidence not found verbatim in the source document, while the governance contract was enforced as executable code. Results: The compendium holds 22,473 association rows spanning 9,265 unique HGNC-validated genes (21,568 unique gene-RCD pairs). Evidence-first adjudication resolved 5,138 pairs (23.8%) as mechanistically involved; across the 4,775 role-resolved pairs, 225 (4.7%) are executors, 4,455 (93.3%) are regulators, and 95 are markers, revealing a small death-executing core embedded in a vast regulatory network. Under a separate seven-class mechanistic criterion applied to all 22,473 rows, only 3,063 (13.6%) were mechanistically confirmed and 286 (1.3%) were database-only with no verifiable paper trail. Conclusion: RCDome makes the RCD evidence landscape measurable and traceable, showing that AI-assisted curation can be verifiable, human-governed, and explicit about uncertainty. It is delivered as a Shiny web application that lets any researcher query the atlas and inspect the evidence behind each association. Availability: RCDome is freely available at https://rcdome.org/ (source code and data at https://github.com/BioCancerInformatics/RCDome).

cell biology↗
bioRxiv2026

Circadian Clock Coordination of the Notch-to-Wnt Signaling Switch Promotes Regenerative Myogenesis

Regenerative deficits of muscle stem cells (MuSCs) contribute to progressive muscle loss in muscular dystrophy. Successful regenerative repair requires a Notch to Wnt switch to allow MuSC expansion and myogenic differentiation, yet the underlying mechanisms remain poorly understood. Leveraging complementary genetic and pharmacological approaches, here we identify the circadian clock as a key regulator of the Notch to Wnt signaling transition to promote regeneration with therapeutic potential for dystrophic disease. Circadian clock activity marks cycling myogenic progenitors during muscle regeneration, and clock induction occurs in concert with Notch activation. We identify that key components of the Notch pathway are direct transcriptional targets of the clock that were induced by clock activation. Mechanistically, clock coordination of Notch and Wnt signaling promoted MuSC proliferative expansion while facilitating myogenic progression during regeneration. Importantly, this clock-regulated mechanism was preserved in dystrophin-deficient mouse and human myoblasts, and clock-activating compounds enhanced regenerative myogenesis in dystrophic muscle. Collectively, our findings uncover a circadian clock-controlled mechanism that orchestrates regenerative signaling transition with potential for therapeutic targeting to restore regenerative capacity in dystrophic disease.

cell biology↗
bioRxiv2026

The yeast Gcn2 protein kinase mediates P-body formation both through its activity with eIF2α and with non-canonical substrates

P-bodies (PBs) are control hubs for RNA processing and storage that form when translation initiation is inhibited, including during stress. In yeast, Gcn2 is the sole eIF2 alpha kinase that inhibits translation initiation in response to diverse stresses. We show that PB formation depends strongly on Gcn2 during amino acid starvation but only partially during oxidative stress. Constitutively active Gcn2 also induces PB formation in unstressed cells. Surprisingly, PBs are still constitutively formed in a gcn3 mutant strain that is insensitive to eIF2 alpha phosphorylation suggesting that Gcn2 also promotes PB formation independently of eIF2 alpha phosphorylation. Analysis of several putative Gcn2-substrates involved in RNA metabolism identified several proteins required for Gcn2-mediated PB formation. Among these, Smu2, which was not previously implicated in PB formation, localises to PBs and is required for stress-induced coalescence of mRNA granules into PBs. Together, our findings indicate that Gcn2 promotes PB formation via two complementary routes: eIF2 alpha phosphorylation, which generates untranslated mRNAs, and Smu2-dependent maturation of mRNA granules into PBs.

cell biology↗