Jagan, A. | bioRxiv Science

bioRxiv2025

Proteomic profiling uncovers sexual dimorphism in the muscle response to wheel running exercise in the FLExDUX4 murine model of facioscapulohumeral muscular dystrophy

FLExDUX4 is a murine experimental model of facioscapulohumeral muscular dystrophy (FSHD) characterized by chronic, low levels of leaky expression of the human full-length double homeobox 4 gene (DUX4-fl). FLExDUX4 mice exhibit mild pathologies and functional deficits similar to people affected by FSHD. Proteomic studies in FSHD could offer new insights into disease mechanisms underpinned by post-transcriptional processes. We used mass spectrometry-based proteomics to quantify the abundance of 1322 proteins in triceps brachii muscle, encompassing both male and female mice in control and free voluntary wheel running (VWR) in Wild-type (n=3) and FLExDUX4 (n=3) genotypes. We report the triceps brachii proteome of FLExDUX4 mice recapitulates key skeletal muscle clinical characteristics of human FSHD, including alterations to mitochondria, RNA metabolism, oxidative stress, and apoptosis. RNA-binding proteins exhibit a sex-specific difference in FLExDUX4 mice. Sexual dimorphism of mitochondrial protein adaptation to exercise was uncovered specifically in FLExDUX4 mice, where females increased, but males decreased mitochondrial proteins after a 6-week of VWR. Our results highlight the importance of identifying sex-specific diagnostic biomarkers to enable more reliable monitoring of FSHD therapeutic targets. Our data provides a resource for the FSHD research community to explore the burgeoning aspect of sexual dimorphism in FSHD. In BriefNishimura et al. conducted proteomic analysis of triceps brachii muscle in the FLExDUX4 murine model of FSHD and verified FLExDUX4 mice recapitulate key skeletal muscle clinical characteristics of human FSHD, including disruptions to the mitochondrial proteome and proteins associated with RNA metabolism, oxidative stress, and apoptosis. RNA-binding proteins and the mitochondrial proteome response to exercise exhibited sexual dimorphism in FLExDUX4 mice. Specifically, females exhibited increases, whereas males exhibited decreases in mitochondrial protein abundance after 6-weeks voluntary wheel running. HighlightsO_LIFLExDUX4 muscle proteome mirrors pathophysiology of FSHD patient myoblasts C_LIO_LIMitochondrial proteins are more abundant in FLExDUX4 as compared to WT mice C_LIO_LISeverity of proteome disruption is greater in male than female mice C_LIO_LIRNA-binding proteins exhibit a sex-specific difference in FLExDUX4 mice C_LIO_LISex-specific mitochondrial proteome response to VWR in FLExDUX4 mice C_LI O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=199 SRC="FIGDIR/small/639012v1_ufig1.gif" ALT="Figure 1"> View larger version (35K): org.highwire.dtl.DTLVardef@1bf8a40org.highwire.dtl.DTLVardef@dad2borg.highwire.dtl.DTLVardef@1e402e7org.highwire.dtl.DTLVardef@7aad7c_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗

bioRxiv2025

Non-targeted Analysis of Extracellular Vesicle-Enriched Plasma Proteome between Early and Late Rugby Playing Career

Rugby players may repeatedly incur high-impact collisions that could predispose them to neurodegenerative conditions but the processes underlying the heightened risk are currently unclear. This project investigates whether the proteome of plasma extracellular vesicles (EV) could carry putative diagnostic biomarkers to indicate differences in risk to neurodegenerative conditions across a rugby playing career. Twenty-four males were recruited, including eight academy players (18 {+/-} 1 y), eight professional rugby players (33 {+/-} 5 y) with >10-year rugby career and eight CrossFit athletes (32 {+/-} 5 y) with no history of collision-related sports injuries. Membrane-bound particles (i.e. EV) were enriched from plasma using hyper-porous strong-anion exchange magnetic microparticles and tryptic peptides were analysed using nano-flow liquid chromatography and high-resolution tandem mass spectrometry. Differences in protein abundance were investigated by one-way analysis of variance (with correction for multiple testing) after label free quantitation. In total, 449 proteins were confidently identified (false discovery rate; FDR <1 %) and gene ontology profiling confirmed 414 of these proteins were of EV origin. One-way ANOVA highlighted 128 significantly (P<0.05, q<0.02) different proteins across the three participant groups, of which 31 proteins were specific to professional rugby players. Seven of these proteins (APOA1, APOM, CLUS, BIP, VCAM1, NID1 and MMP9) which were depleted and one protein ZPI which was elevated have previously recognised roles in neurodegenerative processes. In conclusion, non-targeted analysis highlighted that proteins associated with neuroprotection were specifically depleted in the plasma EV proteome of long-serving professional rugby players compared to younger academy rugby players or age-matched cross-fit athletes that did not have a history of collision-related sports injuries. Our findings shed new light on processes affected by a professional rugby playing career, further application of this type of analysis could be used to develop biomarker panels useful for predicting at-risk athletes or for guiding treatment interventions.

molecular biology↗