bims-moremu 2025-03-23 papers

bims-moremu

Biomed News

on Molecular regulators of muscle mass

Issue of 2025–03–23
thirty-six papers selected by
Anna Vainshtein, Craft Science Inc.

Skeletal muscle atrophy induced by aging and disuse atrophy are strongly associated with the upregulation of the endoplasmic stress protein CHOP in rats.
ERG1A K+ channel increases intracellular calcium concentration through modulation of calsequestrin1 in C2C12 myotubes.
Proteins of the Triadic Excitation-Contraction Coupling Complex in Skeletal Muscle.
ZIP13 marks muscle satellite cells and contributes to their quiescent and active phase balance.
SIRT5 safeguards against primate skeletal muscle ageing via desuccinylation of TBK1.
3-Hydroxybutyrate Promotes Myoblast Proliferation and Differentiation through Energy Metabolism and GPR109a-Mediated Ca2+-NFAT Signaling Pathways.
Becker muscular dystrophy mice showed site-specific decay of type IIa fibers with capillary change in skeletal muscle.
Microgravity-induced changes in skeletal muscle and possible countermeasures: What we can learn from bed rest and human space studies.
Mechanisms, assessment, and exercise interventions for skeletal muscle dysfunction post-chemotherapy in breast cancer: from inflammation factors to clinical practice.
Long-term preservation of muscle function and structure by repeated administration of cardiosphere-derived cells in mdx mice.
The Role and Regulation of Intramuscular Sex Hormones in Skeletal Muscle: A Systematic Review.
Efficient Isolation and Ex Vivo Differentiation of Murine Satellite Cells from Healthy and Dystrophic Muscle.
TNAP expressing adventitial pericytes contribute to myogenesis during foetal development.
Modulation of Fatty Acid Metabolism via Lactate-HCA1 Signaling: Potential Therapeutic Implications.
LncRNA SNHG1 regulates muscle stem cells fate through Wnt/β-catenin pathway.
Neuromuscular junction instability with inactivity: morphological and functional changes after 10 days of bed rest in older adults.
Universal Proteomic Signature After Exercise-Induced Muscle Injury in Muscular Dystrophies.
PoWeR elicits intracellular signaling, mitochondrial adaptations, and hypertrophy in multiple muscles consistent with endurance and resistance exercise training.
Zebrafish and cellular models of SELENON-Congenital myopathy exhibit novel embryonic and metabolic phenotypes.
Loss of MEGF10 Decreases the Number of Perisynaptic Schwann Cells and Innervation of Neuromuscular Junctions in Aging Mice.
SIRT5 slows skeletal muscle ageing by alleviating inflammation.
Six-hour hypoxia induced protein degradation in M. gastrocnemius of 24-day-old mice by activating FOXO1 and suppressing AKT-mTORC1.
Nanoparticle-Driven Skeletal Muscle Repair and Regeneration Through Macrophage-Muscle Stem Cell Interaction.
Proteome of amino acids or IGF1-stimulated pacu muscle cells offers molecular insights and suggests FN1B and EIF3C as candidate markers of fish muscle growth.
Dietary timing enhances exercise by modulating fat-muscle crosstalk via adipocyte AMPKα2 signaling.
Bcl-xL overexpression in T cells preserves muscle mitochondrial structure and function and prevents frailty in old mice.
Enhancing AAV-microdystrophin gene therapy after repeat dosing by blocking phagocytosis.
Physical activity reverses the aging induced decline in angiogenic potential in the fast locomotory muscles of mice.
High-throughput screening identifies bazedoxifene as a potential therapeutic for dysferlin-deficient limb girdle muscular dystrophy.
Physical exercise and epigenetic modifications in skeletal muscle, brain, and heart.
Generation of a novel mouse model of nemaline myopathy due to recurrent NEB exon 55 deletion.
Injectable Skeletal Muscle Constructs Overexpressing GLUT4 for Type 2 Diabetes Intervention.
Advances in Exercise and Nutrition as Therapy in Diabetes.
Rat models of musculoskeletal lysosomal storage disorders and their role in pre-clinical evaluation of gene therapy approaches.
A molecular systems architecture of neuromuscular junction in amyotrophic lateral sclerosis.
MyoD1 localization at the nuclear periphery is mediated by association of WFS1 with active enhancers.

Mol Biol Rep. 2025 Mar 18. 52(1): 322

Skeletal muscle atrophy induced by aging and disuse atrophy are strongly associated with the upregulation of the endoplasmic stress protein CHOP in rats.

J Max Michel, Joshua S Godwin, Nathan R Kerr, Thomas E Childs, Frank W Booth, C Brooks Mobley, David C Hughes, Michael D Roberts.

   BACKGROUND: While canonical anabolic and proteolytic pathways have been well examined in the context of skeletal muscle proteostasis, the roles of endoplasmic reticulum stress (ERS) and the induced unfolded protein response (UPR) are underappreciated. Thus, we aimed to determine whether aging and/or disuse atrophy in rats altered skeletal muscle ERS/UPR markers.
METHODS AND RESULTS: Soleus (SOL) and plantaris (PLT) muscles of 3-month-old (mo), 6 mo, 12 mo, 18 mo, and 24 mo rats (9-10 per group, 48 in total) were analyzed for UPR proteins with further analysis performed on the protein CHOP. The gastrocnemius muscles of 4 mo rats that had undergone hindlimb immobilization (HLI, n = 12) or sham casting (CTL, n = 12) were analyzed for similar targets as well as more extensive CHOP-related targets. CHOP protein was greater in the PLT and SOL of 18 and 24 mo rats versus other age groups (P < 0.05). Moreover, negative correlations existed between CHOP expression and normalized PLT (R=-0.702, P < 0.001) and SOL (R=-0.658, P < 0.001) muscle weights in all rats analyzed at different ages. CHOP protein expression was also greater in the gastrocnemius of HLI versus CTL rats (P < 0.001), and a negative correlation existed between CHOP protein expression and normalized muscle weights in these rats (R=-0.814, P < 0.001). Nuclear CHOP protein levels (P < 0.010) and genes transcriptionally regulated by CHOP were also greater in HLI versus CTL rats (P < 0.001) implicating transcriptional activity of CHOP is elevated during disuse atrophy.
CONCLUSIONS: CHOP is operative during aging- and disuse-induced skeletal muscle atrophy in rodents, and more research is needed to determine if CHOP is a key mechanistic driver of these processes.

Keywords:  Aging; CHOP; Disuse; Endoplasmic reticulum stress; Unfolded protein response

DOI:  https://doi.org/10.1007/s11033-025-10415-4
Sci Rep. 2025 Mar 19. 15(1): 9480

ERG1A K+ channel increases intracellular calcium concentration through modulation of calsequestrin1 in C2C12 myotubes.

Gregory H Hockerman, Evan Pratt, Shalini Guha, Emily LaVigne, Clayton Whitmore, Omar Khader, Natalie McClure, Sandra Zampieri, Jennifer Koran, W-H Wang, Amber L Pond.

  The ERG1A K+ channel modulates the protein degradation that contributes to skeletal muscle atrophy by increasing intracellular calcium concentration ([Ca2+]i) and enhancing calpain activity, but the mechanism by which the channel regulates the [Ca2+]i is not known. Here, we have investigated the effect of human ERG1A (HERG) on [Ca2+]i in C2C12 myotubes, using Fura-2 calcium assays, immunoblot, RT-qPCR, and electrophysiology. The data show that the rise in [Ca2+]i induced by KCl-stimulated depolarization is of greater amplitude in C2C12 myotubes over-expressing HERG relative to controls, but this difference does not result from an increase in L-type channel (Cav1.1) Ca2+ influx because there is no statistical difference in the nifedipine-sensitive response upon depolarization between the expression groups. Indeed, HERG overexpression in C2C12 myotubes has no effect on the amplitude of L-type channel current nor does it affect the mRNA levels nor protein abundance of the Cav1.1 channel. This finding suggests that HERG modulates excitation coupled calcium entry (ECCE). Indeed, the HERG-enhanced increase in [Ca2+]i induced by depolarization is blocked by 2-aminoethoxydiphenyl borate, an inhibitor of ECCE. Further, HERG also modulates the activity of ryanodine receptors (RYR1, a component of ECCE) as well as store operated calcium entry (SOCE). Therefore, we investigated the effect of HERG on calsequestrin1, a calcium buffering/binding protein known to modulate RYR1 and SOCE activities. Indeed, we find that calsequestrin1 mRNA levels are decreased 0.83-fold (p < 0.05) and the total protein abundance is lowered 77% (p < 0.05) in myotubes over-expressing HERG relative to controls. In conclusion, the data show that ERG1A overexpression modulates [Ca2+]i in skeletal muscle cells by lowering the abundance of the calcium buffering/binding protein calsequestrin1 which interacts with RyR1 and SOCE pathways. Indeed, we report that overexpression of HERG in myotubes increases [Ca2+]i by modulation of RyR1 as well as ECCE and SOCE activities. It is likely that HERG enhancement of RyR1 activity, through decreased Casq1 abundance, is increasing [Ca2+]i. This study provides a potential mechanism to explain how upregulation of ERG1A contributes to increased [Ca2+]i and, thus, atrophy in skeletal muscle.

Keywords:  Ether-a-gogo related K+ channel; Intracellular calcium; RyR1; Skeletal muscle; Store operated calcium entry; calsequestrin1

DOI:  https://doi.org/10.1038/s41598-025-93788-7
Cold Spring Harb Perspect Biol. 2025 Mar 17. pii: a041482. [Epub ahead of print]

Proteins of the Triadic Excitation-Contraction Coupling Complex in Skeletal Muscle.

Ting Chang, Rachel Sue Zhen Yee, George G Rodney, Susan L Hamilton.

Excitation-contraction coupling (ECC) in skeletal muscle is mediated by mechanical coupling between the L-type voltage-dependent Ca2+ channel (CaV1.1) in the transverse tubules and the Ca2+ release channel (RYR1) in the sarcoplasmic reticulum (SR). However, ECC complexes are much more complicated than just these two ion channels. Triadic Ca2+ release units (CRUs) that mediate ECC in skeletal muscle are allosterically regulated complexes of ion channels, cytoplasmic modulators, SR transmembrane proteins, and lumenal Ca2+ buffers. While RYR1, CaV1.1α1s, and CaV1.1β1a, the SH3 and cysteine-rich domain protein (STAC3) and junctophilin (JPH1 and/or JPH2) are required for voltage-gated Ca2+ release, other auxiliary proteins modulate this process. In this review, we discuss what is known about the proteins in the triadic protein complex, their roles in ECC, and the mutations in the ECC proteins that give rise to skeletal muscle myopathies.

DOI: https://doi.org/10.1101/cshperspect.a041482
Sci Rep. 2025 Mar 17. 15(1): 9206

ZIP13 marks muscle satellite cells and contributes to their quiescent and active phase balance.

Emi Yoshigai, Takafumi Hara, Masaki Hashimoto, Hidenao Tsuzuki, Takaya Abe, Kenichi Inoue, Ayaka Noguchi, Takuto Ohashi, Toshiyuki Fukada.

  Loss of ZIP13 causes Ehlers-Danlos syndrome spondylodysplastic type 3 involving connective tissue dysplasias associated with a reduction in muscular strength. However, ZIP13 role in skeletal muscle homeostasis, particularly for the regulation of muscle satellite cells (MuSCs), remains poorly understood. In this study, we investigated Zip13-knockout (KO) mice and found a reduction in MuSCs of Zip13-KO mice, in which the quiescent and activated phase balances were disrupted. To clarify the physiological role and dynamics of ZIP13 expression in MuSCs, we generated Zip13-GFP knock-in (KI) mice encoding GFP at the Zip13 locus, which showed that ZIP13 contributes to the phase balance regulation of quiescent and activated MuSCs and their functions. Indeed, Zip13-KO mice exhibited delayed recovery from skeletal muscle injury, indicating ZIP13 requirement for proper skeletal muscle regeneration. Moreover, GFP expression was reduced in the MuSCs of homozygous Zip13-GFP KI mice whose intact ZIP13 expression was perturbed, suggesting that positive feedback mechanisms exist to maintain ZIP13 expression. Altogether, our results illustrate that ZIP13 might be positively involved in skeletal muscle regeneration by controlling the quiescent/activated phase balance of MuSCs through autoregulatory ZIP13 expression, and that newly generated Zip13-GFP KI mice would be useful for investigating the roles and dynamics of ZIP13-expressing cells.

Keywords:  Muscle satellite cells; Skeletal muscle regeneration; ZIP13

DOI:  https://doi.org/10.1038/s41598-025-92501-y
Nat Metab. 2025 Mar 14.

SIRT5 safeguards against primate skeletal muscle ageing via desuccinylation of TBK1.

Qian Zhao, Ying Jing, Xiaoyu Jiang, Xin Zhang, Feifei Liu, Haoyan Huang, Zhihua Zhang, Haijun Wang, Shuhui Sun, Shuai Ma, Weiqi Zhang, Yang Yu, Xiaobing Fu, Guoguang Zhao, Jing Qu, Si Wang, Guang-Hui Liu.

Ageing-induced skeletal muscle deterioration contributes to sarcopenia and frailty, adversely impacting the quality of life in the elderly. However, the molecular mechanisms behind primate skeletal muscle ageing remain largely unexplored. Here, we show that SIRT5 expression is reduced in aged primate skeletal muscles from both genders. SIRT5 deficiency in human myotubes hastens cellular senescence and intensifies inflammation. Mechanistically, we demonstrate that TBK1 is a natural substrate for SIRT5. SIRT5 desuccinylates TBK1 at lysine 137, which leads to TBK1 dephosphorylation and the suppression of the downstream inflammatory pathway. Using SIRT5 lentiviral vectors for skeletal muscle gene therapy in male mice enhances physical performance and alleviates age-related muscle dysfunction. This study sheds light on the molecular underpinnings of skeletal muscle ageing and presents the SIRT5-TBK1 pathway as a promising target for combating age-related skeletal muscle degeneration.

DOI: https://doi.org/10.1038/s42255-025-01235-8
J Proteome Res. 2025 Mar 18.

3-Hydroxybutyrate Promotes Myoblast Proliferation and Differentiation through Energy Metabolism and GPR109a-Mediated Ca2+-NFAT Signaling Pathways.

Xu Qiu, Wenfang Wu, Shuya Zhang, Caihua Huang, Donghai Lin.

  Skeletal muscle wasting is a critical clinical problem associated with several diseases that significantly impair patient outcomes due to the progressive loss of muscle mass and function. This study explores the potential of 3-hydroxybutyrate (3-HB) as a therapeutic agent to counteract muscle atrophy by promoting the proliferation and differentiation of C2C12 myoblasts. Using nuclear magnetic resonance (NMR)-based metabolomics analysis, we uncover the underlying mechanisms by which 3-HB exerts its effects. Our findings demonstrate that 3-HB exerts its effects through two distinct mechanisms: as a metabolic substrate and as a signaling molecule. As a metabolic substrate, 3-HB enhances myoblast energy efficiency by stimulating the expression of G protein-coupled receptor 109a (GPR109a), which subsequently upregulates the 3-HB transporters MCT1 and CD147, the utilization enzyme OXCT1, and phosphorylated AMPK, thereby increasing ATP production. As a signaling molecule, 3-HB activates GPR109a, promoting calcium influx, improving calcium homeostasis, and increasing the expression of Ca2+-related proteins such as CAMKK2. This signaling cascade activates calcineurin (CaN), facilitating NFAT translocation to the nucleus and gene expression that drives myoblast proliferation and differentiation. By elucidating the dual regulatory roles of 3-HB in energy metabolism and cellular signaling, this study not only advances our understanding of muscle physiology but also highlights the potential of 3-HB as a novel therapeutic approach for the prevention or treatment of skeletal muscle atrophy.

Keywords:  GPR109a receptor; cellular signaling; metabolic fuel; metabolomic profiling; myoblast proliferation

DOI:  https://doi.org/10.1021/acs.jproteome.4c01150
Elife. 2025 Mar 17. pii: RP100665. [Epub ahead of print]13

Becker muscular dystrophy mice showed site-specific decay of type IIa fibers with capillary change in skeletal muscle.

Daigo Miyazaki, Mitsuto Sato, Naoko Shiba, Takahiro Yoshizawa, Akinori Nakamura.

  Becker muscular dystrophy (BMD), an X-linked muscular dystrophy, is mostly caused by an in-frame deletion of Duchenne muscular dystrophy (DMD). BMD severity varies from asymptomatic to severe, associated with the genotype of DMD. However, the underlying mechanisms remain unclear. We established BMD mice carrying three representative exon deletions: ex45-48 del., ex45-47 del., and ex45-49 del. (d45-48, d45-47, and d45-49), with high frequencies and different severities in the human BMD hotspot. All three BMD mice showed muscle weakness, muscle degeneration, and fibrosis, but these changes appeared at different times for each exon deletion, consistent with the severities obtained by the natural history study of BMD. BMD mice showed site-specific muscle changes, unlike mdx mice, which showed diffuse muscle changes, and we demonstrated selective type IIa fiber reduction in BMD mice. Furthermore, BMD mice showed sarcolemmal neuronal nitric oxide synthase (nNOS) reduction and morphological capillary changes around type IIa fibers. These results suggest that capillary changes caused by nNOS reduction may be associated with the mechanism of skeletal muscle degeneration and type IIa fiber reduction in BMD mice. BMD mice may be useful in elucidating the pathomechanisms and developing vascular targeted therapies for human BMD.

Keywords:  BMD; genetics; genomics; mouse; mouse models; nNOS; site-specific muscle degeneration; type IIa fiber reduction; vascular formation

DOI:  https://doi.org/10.7554/eLife.100665
Exp Physiol. 2025 Mar 17.

Microgravity-induced changes in skeletal muscle and possible countermeasures: What we can learn from bed rest and human space studies.

Alessandra Bosutti, Bergita Ganse, Nicola A Maffiuletti, Rob C I Wüst, Gustav J Strijkers, Andy Sanderson, Hans Degens.

  Despite exercise countermeasures to sustain health and performance in spaceflight, complete maintenance of muscle mass and functions in microgravity is still not possible for most astronauts. The principal cause of the limited effectiveness of existing exercise countermeasures is the difficulty in achieving full loading forces in space. The implementation of countermeasures which require small devices and simulate Earth-like loading forces to maintain muscle mass, strength and endurance is therefore highly desirable. At present, the cellular mechanisms that induce muscle atrophy in weightlessness are not yet fully known; a better understanding of how skeletal muscle cells adapt to microgravity will help in designing more effective countermeasures to sustain the health and operational capacity of the crew during long- and short-duration missions. The 6° head-down-tilt bed rest is a powerful ground-based analogue platform to simulate and study the physiological effects of spaceflight on the human body, and test the effectiveness of countermeasures before they are potentially applied in space. The aims of this narrative review are therefore to provide an overview of (i) the main mechanisms underlining muscle atrophy learnt from space and bed rest studies, (ii) the currently available countermeasures, and (iii) potential suitable countermeasures - such as neuromuscular electrical stimulation that is delivered with light and small portable units - to attenuate muscle wasting in astronauts during spaceflight.

Keywords:  ISS; NMES; artificial gravity; astronauts; bed rest; microgravity; muscle atrophy; spaceflight

DOI:  https://doi.org/10.1113/EP092345
Front Oncol. 2025 ;15 1551561

Mechanisms, assessment, and exercise interventions for skeletal muscle dysfunction post-chemotherapy in breast cancer: from inflammation factors to clinical practice.

Pei Zhong, Xizhuang Li, Jiehua Li.

  Chemotherapy remains a central component of breast cancer treatment, significantly improving patient survival rates. However, its toxic side effects, along with cancer-related paraneoplastic syndromes, can lead to the loss of skeletal muscle mass and function, impairing physical abilities and increasing the risk of complications during treatment. Chemotherapeutic agents directly impact skeletal muscle cells by promoting protein degradation, inhibiting protein synthesis, and triggering systemic inflammation, all of which contribute to muscle atrophy. Additionally, these drugs can interfere with the proliferation and differentiation of stem cells, such as satellite cells, disrupting muscle regeneration and repair while inducing abnormal differentiation of intermuscular tissue, thereby worsening muscle wasting. These effects not only reduce the effectiveness of chemotherapy but also negatively affect patients' quality of life and disease prognosis. Recent studies have emphasized the role of exercise as an effective non-pharmacological strategy for preventing muscle loss and preserving muscle mass in cancer patients. This review examines the clinical manifestations of muscle dysfunction following breast cancer chemotherapy, the potential mechanisms underlying these changes, and the evidence supporting exercise as a therapeutic approach for improving muscle function.

Keywords:  breast cancer post-chemotherapy; exercise intervention; inflammatory factors; muscle atrophy; sarcopenia; skeletal muscle dysfunction

DOI:  https://doi.org/10.3389/fonc.2025.1551561
Stem Cell Reports. 2025 Mar 11. pii: S2213-6711(25)00072-4. [Epub ahead of print] 102468

Long-term preservation of muscle function and structure by repeated administration of cardiosphere-derived cells in mdx mice.

Russell G Rogers, Jack Antich, Mario Fournier, Ariel Omidfar, Lizbeth Sanchez, Juliet Alfaro, Jonah Zarrow, Nancy Manriquez, Alessandra Ciullo, Jackelyn Valle, Eduardo Marbán.

  Duchenne muscular dystrophy (DMD) is a progressive myodegenerative disease that leads to severe muscle weakness and premature death. Mouse cardiosphere-derived cells (mCDCs) and extracellular vesicles (EVs) secreted by human cardiosphere-deriveds (hCDC-EVs) are therapeutic to mice with advanced-stage DMD. Here, we investigated the long-term benefits of monthly dosing when initiated early. At the endpoint, exercise performance and skeletal muscle function were strikingly preserved in mdx mice that had received mCDCs, but not in vehicle control. In contrast, the beneficial effects of hCDC-EVs waned after 6 months, in parallel with the development of anti-hCDC-EV antibodies. Further investigation showed that mCDCs lowered fibrosis and initiated a myogenic response program in mdx skeletal muscle. Thus, early and sustained intervention with mCDCs prevents disease progression for up to 1 year in mdx mice. This discovery offers new insights into how cell therapy can be used to treat DMD and motivates clinical testing of CDCs beginning in newly diagnosed DMD.

Keywords:  Duchenne muscular dystrophy; cardiosphere-derived cells; cell therapy; extracellular vesicles; regenerative medicine

DOI:  https://doi.org/10.1016/j.stemcr.2025.102468
J Clin Endocrinol Metab. 2025 Mar 18. pii: dgaf174. [Epub ahead of print]

The Role and Regulation of Intramuscular Sex Hormones in Skeletal Muscle: A Systematic Review.

Viktor Engman, Annabel J Critchlow, Eija K Laakkonen, Mette Hansen, Shaun Mason, Séverine Lamon.

   INTRODUCTION: Serum concentrations of androgens and oestrogens, the main male and female sex hormones, respectively, naturally fluctuate across the lifespan. Sex hormones are mainly produced in the gonads, but evidence suggests that they can also be locally synthesised in skeletal muscle. However, little is known about the purpose of intramuscular sex hormones and their role in skeletal muscle. This systematic review aimed to investigate 1) how intramuscular sex hormone concentrations vary across the lifespan, 2) whether exercise affects intramuscular sex hormone concentrations, and 3) whether intramuscular sex hormones are associated with skeletal muscle mass and function.
METHODS: Four databases were searched, and studies were included if they contained measurements of intramuscular sex hormones from healthy males and females free from any hormonal treatment or from rodents.
RESULTS: Thirteen studies were included. Intramuscular testosterone was reduced in older males compared to their younger counterparts, but comparison of intramuscular sex hormone concentrations between pre- and post-menopausal females yielded inconclusive findings. Chronic exercise decreased androgens and oestradiol in females, but increased androgens in males. Acute exercise did not change intramuscular hormone concentrations in humans but increased them in rodents. Intramuscular androgens were positively associated with muscle mass and strength in males. In females, conflicting findings were reported for both oestradiol and androgens, and measures of muscle mass and function.
CONCLUSION: Current evidence suggests that ageing and exercise differentially modulate intramuscular sex hormone concentrations, and their association with muscle mass and function, between males and females, and model systems.

Keywords:  Oestrogen; Sex hormones; Skeletal muscle; Testosterone

DOI:  https://doi.org/10.1210/clinem/dgaf174
Methods Mol Biol. 2025 Mar 22.

Efficient Isolation and Ex Vivo Differentiation of Murine Satellite Cells from Healthy and Dystrophic Muscle.

Alessio A Cusmano, Cordell A VanGenderen, Tim O Lorenz, Yafen Yang, Natasha C Chang.

  Satellite cells are the stem cells of adult skeletal muscles and confer skeletal muscle with remarkable regenerative ability. Under homeostatic conditions, satellite cells reside in a quiescent state in their niche along the basal lamina of muscle fibers. Upon receiving stimuli, satellite cells activate and engage in regenerative myogenesis to repair damaged fibers. Due to the impact of satellite cell differentiation on muscle physiology, studying their differentiation is relevant both within the context of healthy and diseased muscle. Due to the abundance of cell populations within skeletal muscle, the study of satellite cells is predicated on isolating highly pure populations. Fluorescence activated cell sorting (FACS) represents the gold standard for deriving highly pure satellite cell isolates but is costly and can reduce cell viability. In addition, proliferating satellite cells in vitro invariably transition to a homogeneous myoblast population that bestows a selective advantage on fast-dividing cells, reducing satellite cell heterogeneity. In this chapter, we describe our protocol for magnetic-activated cell sorting (MACS) of satellite cells. MACS preserves cell viability to a greater degree than FACS, and our approach allows for highly pure sorted populations of satellite cells. In addition, sorted cells can enter and progress through the myogenic program immediately upon plating, avoiding the need for lengthy expansion periods.

Keywords:  Differentiation; Ex vivo culture; Immunostaining; Magnetic-activated cell sorting (MACS); Muscle dissociation; Muscle stem cell; Myogenesis; Primary cell isolation; Satellite cell

DOI:  https://doi.org/10.1007/7651_2025_608
Vascul Pharmacol. 2025 Mar 15. pii: S1537-1891(25)00028-X. [Epub ahead of print] 107489

TNAP expressing adventitial pericytes contribute to myogenesis during foetal development.

I Fancello, S Willett, C Castiglioni, S Amer, S Santoleri, L Bragg, F Galli, G Cossu.

   OBJECTIVE: During growth and differentiation of skeletal muscle, cell types other than canonical myoblasts can be recruited to a myogenic fate. Among these, TNAP+ pericytes can differentiate into skeletal or smooth muscle cells during postnatal growth and contribute to muscle regeneration. However, their role in muscle development has not been investigated. This study aims to characterise pericyte fate choices during embryonic and foetal myogenesis, occurring in the second half of gestation.
APPROACH AND RESULTS: Using Cre-loxP lineage tracing with multiple reporters including the multifluorescent Confetti, we labelled TNAP+ precursors in vivo and assessed the smooth or skeletal muscle differentiation in their lineage at a perinatal stage. We found that TNAP+ cells contribute in vivo to skeletal and smooth muscle cells, as well as other pericytes, also during pre-natal muscle development. The resulting clones showed that such fate choices are likely to depend on distinct unipotent progenitors rather than multipotent progenitors. In addition, we isolated and differentiated in vitro foetal cells derived from TNAP+ precursors, which showed that they are not spontaneously myogenic unless co-cultured with other skeletal muscle cells.
CONCLUSIONS: This work extends our understanding of the differentiative potency of these non- canonical skeletal muscle progenitors during prenatal life, with a view to a future application of this knowledge to optimise cell therapies for muscle wasting disorders.

Keywords:  Lineage tracing; Pericytes; Skeletal myogenesis

DOI:  https://doi.org/10.1016/j.vph.2025.107489
Am J Physiol Cell Physiol. 2025 Mar 17.

Modulation of Fatty Acid Metabolism via Lactate-HCA1 Signaling: Potential Therapeutic Implications.

Isaac A Chavez-Guevara, Manuel Fermandez-Escabias, Marco A Hernandez-Lepe, Francisco J Amaro-Gahete.

  The lactate/HCA1 signaling pathway has emerged as a promising target for the clinical management of metabolic diseases, given its regulatory effects on triglyceride turnover and mobilization. However, the differential roles of this pathway in adipose tissue, skeletal muscle, and the liver raise important questions about whether its activation or inhibition would yield the most favorable outcomes. In adipose tissue, HCA1 activation suppresses lipolysis, while in skeletal muscle, recent evidence suggests that lactate may bypass HCA1 to directly enhance mitochondrial fatty acid oxidation. In the liver, HCA1 activation has been implicated in promoting lipid oxidation, offering potential therapeutic implications. This perspective also explores the potential of the lactate/HCA1 pathway to mediate systemic adaptations induced by exercise training, including enhanced mitochondrial capacity and metabolic flexibility. These insights underscore the pathway's relevance for both metabolic health and exercise physiology. However, the current understanding of the lactate/HCA1 pathway remains incomplete, with critical gaps in knowledge regarding its role in underrepresented populations and the molecular mechanisms underlying its tissue-specific effects. Addressing these limitations will be essential for refining the therapeutic and clinical applications of this pathway.

Keywords:  cell biology; endocrinology and metabolism; exercise physiology

DOI:  https://doi.org/10.1152/ajpcell.00969.2024
Dev Dyn. 2025 Mar 21.

LncRNA SNHG1 regulates muscle stem cells fate through Wnt/β-catenin pathway.

Changying Wang, Wenwen Wu, Junyi Chen, Heng Wang, Pengxiang Zhao.

   BACKGROUND: Skeletal muscle stem cells (MuSCs) played an important role in maintaining the proper function of muscle tissues. In adults, they normally remained in a quiescent state and activated upon stimulation to undergo self-renewal or myogenic differentiation. This process was complexly regulated by cytokines, and the molecular mechanisms that promoted MuSCs activation remained largely unknown.
RESULTS: Here, we analyzed transcriptome data from MuSCs activated by different stimuli using weighted gene co-expression network analysis (WGCNA) and identified the key long non-coding RNA SNHG1 (lncSNHG1), which promotes the transition from the quiescent to the activated state of MuSCs. Overexpression of lncSNHG1 was able to promote the proliferation and differentiation of MuSCs, whereas knockdown resulted in the opposite results. Mechanistically, the disruption of the Wnt/β-catenin pathway blocked the quiescence exit induced by lncSNHG1.
CONCLUSIONS: We conclude that lncSNHG1 is a key factor that promotes the transition from the quiescent to the activated state of MuSCs and promotes cell proliferation and differentiation through the Wnt/β-catenin pathway.

Keywords:  LncRNA; SNHG1; WGCNA; Wnt; muscle stem cells

DOI:  https://doi.org/10.1002/dvdy.70017
J Physiol. 2025 Mar 17.

Neuromuscular junction instability with inactivity: morphological and functional changes after 10 days of bed rest in older adults.

Evgeniia Motanova, Fabio Sarto, Samuele Negro, Marco Pirazzini, Ornella Rossetto, Michela Rigoni, Daniel W Stashuk, Mladen Gasparini, Boštjan Šimunic, Rado Pišot, Marco V Narici.

  The neuromuscular junction (NMJ) plays a key role in modulating muscle contraction, but the impact of short-term disuse on NMJ structure and function, particularly in older humans, remains unclear. This study aimed to investigate NMJ alterations following 10 days of horizontal bed rest in 10 older males (68.5 ± 2.6 years). Before and after bed rest, vastus lateralis muscle biopsies were obtained to evaluate NMJ morphology, intramuscular EMG (iEMG) was recorded to assess NMJ function and blood samples were collected to determine circulating C-terminal agrin fragment (CAF) concentration, a biomarker of NMJ remodelling. In a sub-cohort of six participants who had NMJs in both pre- and post-bed rest biopsies, we observed altered NMJ morphology, including reduced overlap between NMJ terminals, as well as increased endplate area and perimeter. CAF concentration was elevated after bed rest, suggesting ongoing NMJ remodelling. iEMG analysis showed increased motor unit potential complexity and reduced firing rate. In addition, we observed impaired NMJ transmission, inferred from increased near-fibre jiggle and segment jitter. These findings suggest that older male individuals are susceptible to NMJ remodelling and impaired transmission with short-term disuse, providing valuable insights into the morphological and functional consequences of inactivity in an ageing population. Our study highlights the importance of developing interventions for mitigating the detrimental consequences of inactivity on neuromuscular health in older adults, which they frequently experience following injury, trauma, illness or surgery. KEY POINTS: The neuromuscular junction (NMJ) is crucial for signal transmission between the motoneuron and skeletal muscle, and NMJ alterations are linked to several neuromuscular disorders, as well as ageing. However, the impact of disuse on the structural and functional integrity of the NMJ, particularly in older humans, is largely unknown. We used the bed rest model to study the impact of inactivity on NMJ morphology and function in older men. We hypothesised that a 10 day bed rest period would lead to alterations in NMJ morphology and transmission. We show that 10 days of bed rest were sufficient to induce marked alterations in NMJ morphology, associated with an impaired NMJ transmission and with changes in motor unit potential properties. These findings suggest that older male individuals are vulnerable to NMJ dysfunction in response to inactivity and emphasise the importance of maintaining an active lifestyle for preserving neuromuscular health with ageing.

Keywords:  C‐terminal agrin fragment; NMJ; ageing; disuse; electromyography; motor unit; unloading

DOI:  https://doi.org/10.1113/JP288448
Ann Clin Transl Neurol. 2025 Mar 20.

Universal Proteomic Signature After Exercise-Induced Muscle Injury in Muscular Dystrophies.

Mads G Stemmerik, Benjamin Barthel, Nanna R Andersen, Sofie V Skriver, Alan J Russell, John Vissing.

   OBJECTIVE: Several neuromuscular disorders (NMDs) are characterized by progressive muscle damage and are marked by the elevation of circulating muscle proteins from activity-related injury. Despite a diverse array of genetic drivers, many NMDs share similar patterns of exercise intolerance and higher concentrations of muscle injury proteins relative to unaffected individuals. While the interplay between the nature of the muscle injury and the specific genetic driver is poorly understood, the similarities exhibited by various NMDs suggest that a common proteomic signature of muscle injury may exist.
METHODS: We used an established exercise challenge and the SOMAscan proteomics platform to study the baseline and post-exercise proteomic profiles in a cross-sectional study of three different muscular dystrophies: Becker muscular dystrophy (BMD) and limb girdle muscular dystrophy types R9 and R12.
RESULTS: Our Results Uncover a Common Signature of Circulating Proteins That Are Elevated in all Three Myopathies, Some of Which Are Further Elevated by Exercise in Becker Muscular Dystrophy and Limb Girdle Muscular Dystrophy Type R9, and Others That Are Not Responsive to Exercise.
INTERPRETATION: Interestingly, these two signatures exhibit opposing trajectories with age in a larger cross-sectional cohort of BMD individuals. This research represents a first step toward defining an annotated protein signature coupled with activity-injury, a defining pathophysiological feature of many myopathies.

Keywords:  exercise; muscular dystrophy; proteomics

DOI:  https://doi.org/10.1002/acn3.70035
J Appl Physiol (1985). 2025 Mar 18.

PoWeR elicits intracellular signaling, mitochondrial adaptations, and hypertrophy in multiple muscles consistent with endurance and resistance exercise training.

Christian J Elliehausen, Szczepan S Olszewski, Dennis M Minton, Audrey L Spiegelhoff, Carolyn G Shult, Wenyuan G Zhu, Troy A Hornberger, Adam R Konopka.

  Physical activity guidelines recommend both endurance and resistance exercise to improve and maintain overall health. Recently, progressive weighted wheel running (PoWeR), a voluntary, progressive, and high-volume exercise paradigm, was posited as a singular prototype of combined endurance and resistance exercise in mice as evident by enhanced capillarization and hypertrophy of select plantar flexor muscles. Despite growing interest in this model, it remains incompletely characterized if PoWeR resembles the acute and chronic responses to resistance and/or endurance exercise in humans. Therefore, the purpose of this study was to assess canonical signaling events, mitochondrial bioenergetics, and cellular adaptations across multiple extensor and flexor muscles of the fore- and hindlimbs that may be conducive for whole-body functional improvements as traditionally observed in humans. 8-weeks of PoWeR (~8km/day) improved glucose metabolism, exercise capacity, body composition, and bone mineral density as well as increased mass, myofiber CSA, and oxidative myofiber type distribution in the soleus, plantaris, and FDL. Using two ex-vivo high-resolution flourorespirometry protocols that model in vivo physiological conditions, PoWeR decreased mitochondrial ADP sensitivity which was accompanied by greater mitochondrial H2O2 emissions, respiration, conductance, and protein content in the vastus lateralis, gastrocnemius, and triceps in muscle-specific fashion. Three days of short-term PoWeR stimulated mTORC1 and AMPK signaling in soleus, plantaris and/or FDL in line with the hypertrophic and metabolic adaptations observed with long-term training. Collectively, these data support PoWeR as a suitable paradigm in mice to model the acute signaling and chronic adaptations associated with endurance and resistance exercise in humans.

Keywords:  Hypertrophy; mTOR; metabolism; mitochondria; reactive oxygen species

DOI:  https://doi.org/10.1152/japplphysiol.00872.2024
Skelet Muscle. 2025 Mar 15. 15(1): 7

Zebrafish and cellular models of SELENON-Congenital myopathy exhibit novel embryonic and metabolic phenotypes.

Pamela Barraza-Flores, Behzad Moghadaszadeh, Won Lee, Biju Isaac, Liang Sun, Emily T Hickey, Shira Rockowitz, Piotr Sliz, Alan H Beggs.

   BACKGROUND: SELENON-Congenital Myopathy (SELENON-CM) is a rare congenital myopathy caused by mutations of the SELENON gene characterized by axial muscle weakness and progressive respiratory insufficiency. Muscle histopathology may be non-specific, but commonly includes multiminicores or a dystrophic pattern. The SELENON gene encodes selenoprotein N (SelN), a selenocysteine-containing redox enzyme located in the endo/sarcoplasmic reticulum membrane where it colocalizes with mitochondria-associated membranes. However, the molecular mechanism(s) by which SelN deficiency cause SELENON-CM remain poorly understood. A hurdle is the lack of cellular and animal models that show easily assayable phenotypes.
METHODS: Using CRISPR-Cas9 we generated three zebrafish models of SELENON-CM, which were then studied by spontaneous coiling, hatching, and activity assays. We also performed selenon coexpression analysis using a single cell RNAseq zebrafish embryo-atlas. SelN-deficient myoblasts were generated and assayed for glutathione, reactive oxygen species, carbonylation, and nytrosylation levels. Finally, we tested Selenon-deficient myoblasts' metabolism using a Seahorse cell respirometer.
RESULTS: We report deep-phenotyping of SelN-deficient zebrafish and muscle cells. SelN-deficient zebrafish exhibit changes in embryonic muscle function and swimming activity in larvae. Analysis of single cell RNAseq data in a zebrafish embryo-atlas revealed coexpression of selenon and genes involved in the glutathione redox pathway. SelN-deficient zebrafish and mouse myoblasts exhibit altered glutathione and redox homeostasis, as well as abnormal patterns of energy metabolism, suggesting roles for SelN in these functions.
CONCLUSIONS: These data demonstrate a role for SelN in zebrafish early development and myoblast metabolism and provide a basis for cellular and animal model assays for SELENON-CM.

Keywords:  Congenital myopathy; Multiminicore myopathy; Rigid spine muscular dystrophy; Selenoprotein N; Zebrafish model

DOI:  https://doi.org/10.1186/s13395-025-00376-4
J Peripher Nerv Syst. 2025 Mar;30(1): e70014

Loss of MEGF10 Decreases the Number of Perisynaptic Schwann Cells and Innervation of Neuromuscular Junctions in Aging Mice.

Devin Juros, Robert Louis Hastings, Ariane Pendragon, Jeremy Kay, Gregorio Valdez.

   BACKGROUND AND AIMS: At the neuromuscular junction (NMJ), the synapse between motor neurons and muscle fibers, reside perisynaptic Schwann cells (PSCs) which are specialized glia that regulate the maintenance and repair of this synapse. While we know how PSC morphology and numbers change in aging and various neuromuscular disorders that adversely affect the NMJ, the molecular mechanisms that alter PSC functions remain unknown. In this study, we investigated whether MEGF10 in PSCs modulates NMJ stability in developing, healthy young adult, middle-aged, and axotomized mice. MEGF10 is a glial phagocytic receptor that is enriched in PSCs compared to other Schwann cells (SCs).
METHODS: We isolated PSCs from a transgenic reporter mouse line to assess Megf10 expression at different ages and following nerve injury using qPCR. We then used a conditional mouse lacking Megf10 in all SCs, including PSCs (Megf10 SC-KO mice). We examined NMJs and axonal debris clearance in Megf10 SC-KO mice using confocal microscopy.
RESULTS: We found that Megf10 expression in PSCs peaks during development and decreases during aging and following denervation of NMJs. NMJs were morphologically normal in developing and young adult Megf10 SC-KO mice. This was not the case in middle-aged Megf10 SC-KO mice, in which NMJs presented with fewer PSCs, decreased PSC coverage of the endplate, and decreased innervation in comparison to control mice. Following nerve injury-induced damage, axonal debris at the NMJ was cleared faster in Megf10 SC-KO mice; yet, the rate of reinnervation was unchanged compared to control mice.
INTERPRETATION: The data in this study suggest that MEGF10 in PSCs functions to maintain PSC number and NMJ innervation during aging. This study also suggests important roles for MEGF10 in mediating the clearance of axonal debris at NMJs following nerve injury.

Keywords:   Megf10 ; aging; neuromuscular junction; perisynaptic Schwann cell; phagocytosis

DOI:  https://doi.org/10.1111/jns.70014
Nat Metab. 2025 Mar 14.

SIRT5 slows skeletal muscle ageing by alleviating inflammation.

Vera Gorbunova, Andrei Seluanov.

DOI: https://doi.org/10.1038/s42255-025-01228-7
Am J Physiol Endocrinol Metab. 2025 Mar 17.

Six-hour hypoxia induced protein degradation in M. gastrocnemius of 24-day-old mice by activating FOXO1 and suppressing AKT-mTORC1.

Jingyi Song, Marcel Jaklofsky, Claudia Carmone, Vincent de Boer, Niels Wever, Jaap Keijer, Sander Grefte.

  Long-term hypoxia has been associated with skeletal muscle atrophy, including increased protein degradation over protein synthesis. This contrasts sharply with muscle hypertrophy and net protein synthesis occurring in developing skeletal muscle of young mice. Here, we aimed to understand the impact of acute, physiologically plausible environmental hypoxia on muscle proteostasis of the M. gastrocnemius of young mice. Fasted prepubertal, 24-day-old male B6JRccHsd(B6J)-Nnt+/Wuhap mice with similar body weight and lean mass were exposed to normobaric hypoxia (12% O2) or normoxia (20.9% O2) for 6 hours. The transcriptome (n=12) and protein (n=6) response of the M. gastrocnemius were analyzed. A hypoxic response of M. gastrocnemius was confirmed by increased expression of HIF1 (Ankrd37 and Ddit4) and forkhead box-O (FOXO) 1 (Depp1 and Ddit4) target genes. RNA-Seq analysis revealed that hypoxia activated FOXO signaling, which was confirmed by increased FOXO1 protein levels and decreased p-AKT/AKT ratio. Detailed mapping of the FOXO1 pathway suggests a strong FOXO1-mediated hypoxic effect on protein degradation and synthesis. A central role of Atf4 is suggested by the hypoxic-dependent positive correlations with FOXO1, FBXO32, Depp1, Eif4ebp1 and Ddit4. Further analyses showed increased FBXO32, which positively correlated with FOXO1, and decreased p-S6K/S6K and p-4E-BP1/4E-BP1 ratios. Our results showed for the first time that a 6-hour exposure to 12% O2 normobaric hypoxia in 24-day-old mice activates FOXO1 signaling in M. gastrocnemius, resulting in decreased protein synthesis and increased protein degradation most likely via reduced energy availability, which may be relevant for infant air or high altitude traveling.

Keywords:  FOXO1; Hypoxia; Proteostasis; Skeletal muscle; mTORC1

DOI:  https://doi.org/10.1152/ajpendo.00508.2024
Small. 2025 Mar 20. e2412611

Nanoparticle-Driven Skeletal Muscle Repair and Regeneration Through Macrophage-Muscle Stem Cell Interaction.

Lining Xu, Yingyu Zhang, Dingding Wang, Quanzhong Ren, Yi Wang, Zetong Zang, Anyi Guo, Jianxun Guo, Ling Wang, Renxian Wang, Yajun Liu.

  Macrophages are key innate immune cells in the muscle environment of sarcopenia patients, significantly influencing muscle stem cell (MuSC) proliferation and differentiation. However, prolonged activation of macrophages can hinder muscle recovery. In this study, it synthesizes lipoic acid-modified gold nanoparticles (LA-Au NPs) of varying sizes to evaluate their biocompatibility and immunomodulatory effects. The findings demonstrate that LA-Au NPs exhibit excellent biocompatibility with macrophages and promoted M2 polarization in a size-dependent manner. Mechanistically, LA-Au NPs facilitated metabolic reprogramming in macrophages by enhancing lysosomal autophagy and mitochondrial oxidative phosphorylation. Furthermore, macrophages are shown to chemotax toward MuSCs, regulating their proliferation via the chemokine system, inhibiting MuSC apoptosis, and enhancing differentiation under inflammatory conditions. In vivo studies have confirmed the safety and efficacy of LA-Au NPs in sarcopenia mice. To further enhance the effectiveness of LA-Au NPs, it investigates a delivery strategy that involves preconditioning macrophages with LA-Au NPs (Mac@Au NPs). Compared to the direct injection of LA-Au NPs, Mac@Au NPs demonstrate significantly greater benefits for muscle repair. This highlights the potential of macrophage therapy as a promising strategy for effective muscle regeneration and therapeutic intervention in sarcopenia.

Keywords:  gold nanoparticles; immunometabolism; macrophages; muscle stem cells; skeletal muscle regeneration

DOI:  https://doi.org/10.1002/smll.202412611
Biochem Biophys Res Commun. 2025 Mar 15. pii: S0006-291X(25)00362-6. [Epub ahead of print]757 151648

Proteome of amino acids or IGF1-stimulated pacu muscle cells offers molecular insights and suggests FN1B and EIF3C as candidate markers of fish muscle growth.

Erika S Perez, Rafaela A Ribeiro, Bruna Tt Zanella, Fernanda LA Almeida, Josefina Blasco, Daniel Garcia de la Serrana, Maeli Dal-Pai-Silva, Bruno Os Duran.

  Study of fish skeletal muscle is essential to understand physiological or metabolic processes, and to develop programs searching for increased muscle mass and meat production. Amino acids (AA) and IGF1 stimulate processes that lead to muscle growth, but their signaling pathways and molecular regulation need further clarification in fish. We obtained the proteome of pacu (Piaractus mesopotamicus) cultured muscle cells treated with AA or IGF1, which induced the differential abundance of 67 and 53 proteins, respectively. Enrichment analyses showed that AA modulated histone methylation, cell differentiation, and metabolism, while IGF1 modulated ATP production and protein synthesis. In addition, we identified molecular networks with candidate markers that commonly regulate fish muscle cells: FN1B and EIF3C, respectively up- and down-regulated by both treatments. FN1B was related to cell proliferation, protein synthesis, and muscle repair, while EIF3C connected with negative regulators of muscle growth. Their gene expression was evaluated in pacu and Nile tilapia (Oreochromis niloticus) after nutrient manipulation, with fn1b increased during refeeding and eif3c increased during fasting in both species. Our work helps clarify the molecular regulation by AA or IGF1 and suggests that FN1B and EIF3C could be potential stimulatory and inhibitory biomarkers of fish muscle growth.

Keywords:  Bioinformatics; Cell culture; Fish; Proteome; Skeletal muscle

DOI:  https://doi.org/10.1016/j.bbrc.2025.151648
Cell Metab. 2025 Mar 12. pii: S1550-4131(25)00065-8. [Epub ahead of print]

Dietary timing enhances exercise by modulating fat-muscle crosstalk via adipocyte AMPKα2 signaling.

Jianghui Chen, Jing Xiang, Meiyu Zhou, Rongfeng Huang, Jianxin Zhang, Yuanting Cui, Xiaoqing Jiang, Yang Li, Runchao Zhou, Haoran Xin, Jie Li, Lihua Li, Sin Man Lam, Jianfang Zhu, Yanxiu Chen, Qingyuan Yang, Zhifu Xie, Guanghou Shui, Fang Deng, Zhihui Zhang, Min-Dian Li.

  Feeding rhythms regulate exercise performance and muscle energy metabolism. However, the mechanisms regulating adipocyte functions remain unclear. Here, using multi-omics analyses, involving (phospho-)proteomics and lipidomics, we found that day-restricted feeding (DRF) regulates diurnal rhythms of the mitochondrial proteome, neutral lipidome, and nutrient-sensing pathways in mouse gonadal white adipose tissue (GWAT). Adipocyte-specific knockdown of Prkaa2 (the gene encoding AMPKα2) impairs physical endurance. This defect is associated with altered rhythmicity in acyl-coenzyme A (CoA) metabolism-related genes, a loss of rhythmicity in the GWAT lipidome, and circadian remodeling of serum metabolites-in particular, lactate and succinate. We also found that adipocyte Prkaa2 regulates muscle clock genes during DRF. Notably, oral administration of the AMPK activator C29 increases endurance and muscle functions in a time-of-day manner, which requires intact adipocyte AMPKα2 signaling. Collectively, our work defines adipocyte AMPKα2 signaling as a critical regulator of circadian metabolic coordination between fat and muscle, thereby enhancing exercise performance.

Keywords:  AMPK; adipocyte; adipose tissue; chrono-medicine; circadian clock; circadian rhythm; day-restricted feeding; exercise physiology; feeding rhythm; multi-omics

DOI:  https://doi.org/10.1016/j.cmet.2025.02.007
Sci Adv. 2025 Mar 21. 11(12): eadr1378

Bcl-xL overexpression in T cells preserves muscle mitochondrial structure and function and prevents frailty in old mice.

Cristina Mas-Bargues, Aurora Román-Domínguez, Jorge Sanz-Ros, Nekane Romero-García, Javier Huete-Acevedo, Mar Dromant, Ana María Cuervo, Consuelo Borrás, José Viña.

Our previous transcriptomic analysis revealed an up-regulation of the antiapoptotic protein B cell lymphoma-extra large (Bcl-xL) in centenarians relative to octogenarians or younger cohorts. In this study, we used Bcl-xL-overexpressing mice to assess its impact on successful aging. Our findings indicate that Bcl-xL overexpression modifies T cell subsets and improves their metabolism, apoptosis resistance, macroautophagy, and cytokine production during aging. This more resilient immune system reduces inflammation and preserves mitochondrial integrity and function in muscle tissue, thereby retarding the onset of frailty. These results underscore the important contribution of Bcl-xL to healthy aging, a phenomenon that is conserved across mammalian species.

DOI: https://doi.org/10.1126/sciadv.adr1378
Front Immunol. 2025 ;16 1527840

Enhancing AAV-microdystrophin gene therapy after repeat dosing by blocking phagocytosis.

Rita Spathis, Deeva Robles Kuriplach, Sabrina Narvesen, Matthew Eybs, Karen Huang, Steven Torres, Madison King, Elizabeth Bagley, Pia Elustondo, Michael W Lawlor, Kanneboyina Nagaraju, Melissa Morales.

   Background: Inefficient transduction is a major limitation in achieving therapeutic levels of AAV-delivered microdystrophin capable of improving muscle function in patients with Duchenne muscular dystrophy. Additionally, some patients experience acute complications due to activation of innate immune pathways, such as complement. We propose that inhibiting complement receptor 1/2/3 (CR 1/2/3)-mediated phagocytosis and endosomal TLR 7/8/9 signaling pathways may decrease immune and inflammatory responses while simultaneously increasing the availability of AAV virus for muscle transduction.
Methods: Mdx mice were randomly assigned to the following three experimental conditions (n=8-9/group): Group 1, mdx untreated; Group 2, mdx + rAAV9-microdystrophin; Group 3, mdx + rAAV9-microdystrophin + semiweekly dosing of TLR 7/8/9 antagonist + complement receptor antibodies (combination therapy). The rAAV9-microdystrophin was administered twice to 6- and 12-week-old mice. A separate group of 6-week-old mice received a single rAAV9-microdystrophin dose and no other treatment (Group 4). We assessed several immune and inflammatory responses and dystrophin expression in the muscle.
Results: Viral load was significantly increased by 77-fold in white blood cells after two rAAV9-microdystrophin doses compared to mice receiving a single dose. Repeated gene therapy resulted in a lower viral load and microdystrophin expression in muscle compared to a single rAAV dose. 63% of mice treated with two rAAV9-microdystrophin doses produced antibodies to dystrophin, which was less in mice treated with two rAAV9-microdystrophin doses and combination therapy (25%). Likewise, AAV capsid specific antibody levels were reduced in mice receiving combination therapy. Microdystrophin expression in skeletal muscle evaluated by mass spectrometry, immunofluorescence, and western blotting showed significantly higher levels in combination-treated mice compared to rAAV9-microdystrophin alone.
Conclusions: Our results demonstrate that combination treatment with complement receptor 1/2/3 antibodies and a TLR 7/8/9 antagonist enhances rAAV9-microdystrophin gene therapy in mdx mice by partially reducing inflammatory and immune responses and increasing microdystrophin expression in skeletal muscle. Furthermore, repeated gene therapy is associated with greater uptake by white blood cells and less microdystrophin expression in the skeletal muscle. This suggests that blocking complement receptors and/or TLR 7/8/9 pathways would be a promising strategy to enhance AAV-microdystrophin therapy.

Keywords:  AAV9; DMD; Duchenne muscular dystrophy; TLR; complement; gene therapy; immune response; mdx

DOI:  https://doi.org/10.3389/fimmu.2025.1527840
Sci Rep. 2025 Mar 14. 15(1): 8848

Physical activity reverses the aging induced decline in angiogenic potential in the fast locomotory muscles of mice.

Magdalena Zmudzka, Joanna Szramel, Janusz Karasinski, Zenon Nieckarz, Jerzy A Zoladz, Joanna Majerczak.

  Fast locomotory muscles, which are responsible for generating the highest power outputs, are more vulnerable to aging than slow muscles. In this study, we aimed to evaluate the impact of middle age and voluntary physical activity on capillarization and angiogenic potential in fast locomotory muscles. Middle-aged (M-group) and young (Y-group) wild-type FVB female mice were randomly assigned to either the sedentary or trained group undergoing 8-week spontaneous wheel running (8-sWR). Capillary density (assessed via immunohistochemical capillary staining and Western immunoblotting) of the fast locomotory muscles in the M-group (15-months old) was not significantly different compared to the Y-group (4-months old). Nevertheless, the expression of key pro-angiogenic genes in the fast muscle of the M-group was lower than that in the fast muscle of Y-group. 8-sWR had no impact on muscle capillarization; however, it increased fast muscle Vegfa expression in both the M and Y groups. We concluded that although fast muscle capillarization is still preserved in middle age, nevertheless the angiogenic potential (at least at the level of gene expression) is significantly reduced at this stage of aging. Moderate-intensity voluntary physical activity had no effect on capillary density, but it increased the angiogenic potential of the fast muscle.

Keywords:  Aging; Angiogenesis; Capillarization; Physical activity

DOI:  https://doi.org/10.1038/s41598-025-93176-1
Br J Pharmacol. 2025 Mar 19.

High-throughput screening identifies bazedoxifene as a potential therapeutic for dysferlin-deficient limb girdle muscular dystrophy.

Celine Bruge, Nathalie Bourg, Emilie Pellier, Johana Tournois, Jerome Polentes, Manon Benabides, Noella Grossi, Anne Bigot, Anthony Brureau, Isabelle Richard, Xavier Nissan.

   BACKGROUND AND PURPOSE: Limb-girdle muscular dystrophy R2 (LGMD R2) is a rare genetic disorder characterised by progressive weakness and wasting of proximal muscles. LGMD R2 is caused by the loss of function of dysferlin, a transmembrane protein crucial for plasma membrane repair in skeletal muscles. This study aimed to identify drugs that could improve the localisation and restore the function of an aggregated mutant form of dysferlin (DYSFL1341P).
EXPERIMENTAL APPROACH: We developed an in vitro high-throughput assay to monitor the expression and reallocation of aggregated mutant dysferlin (DYSFL1341P) in immortalised myoblasts. After screening 2239 clinically approved drugs and bioactive compounds, the ability of the more promising candidates to improve cell survival following hypo-osmotic shock was assessed. Their protective effects were evaluated on immortalised myoblasts carrying other dysferlin mutations and on dysferlin-deficient muscle fibres from Bla/J mice.
KEY RESULTS: We identified two compounds, saracatinib and bazedoxifene, that increase dysferlin content in cells carrying the DYSFL1341P mutation. Both drugs improved cell survival and plasma membrane resistance following osmotic shock. Whereas saracatinib acts specifically on misfolded L1341P dysferlin, bazedoxifene shows an additional protective effect on dysferlin KO immortalised myoblasts and mice muscle fibres. Further analysis revealed that bazedoxifene induces autophagy flux, which may enhance the survival of LGMD R2 myofibres.
CONCLUSION AND IMPLICATIONS: Our drug screening identified saracatinib and bazedoxifene as potential treatments for LGMD R2, especially for patients with the L1341P mutation. The widespread protective effect of bazedoxifene reveals a new avenue toward genotype-independent treatment of LGMD R2 patients.

Keywords:  autophagy; bazedoxifene; dysferlin; high‐throughput screening assay; limb‐girdle muscular dystrophies; misfolded protein; saracatinib

DOI:  https://doi.org/10.1111/bph.70017
Epigenetics Chromatin. 2025 Mar 21. 18(1): 12

Physical exercise and epigenetic modifications in skeletal muscle, brain, and heart.

Xi Zheng, Xueli Liu, Yuqian Guo, Yi Lv, Chensheng Lin, Dan Wang, Shaobing Wang, Yiping Liu, Xuefeng Hu.

  The origins of many diseases can be traced to the dynamic interplay of genetic predispositions and environmental exposures post-birth. Epigenetic modifications have recently gained prominence as a significant mediator between genetic information and environmental factors, influencing the occurrence and progression of disease. There is a burgeoning body of evidence supports that physical exercise, acting as an external environmental stimulus, exerts a discernible impact on major epigenetic modifications, including histone modifications, DNA methylation, RNA methylation, and non-coding RNA. This effect assumes a pivotal role in the pathogenesis of various human diseases. Exploring the epigenetic molecular mechanisms through which physical exercise enhances human health holds the promise of deepening our understanding of how it improves physiological functions, mitigates disease risks, and establishes a theoretical foundation for employing physical exercise as a non-pharmacological intervention in disease prevention and treatment.

Keywords:  Brain; DNA methylation; Heart; Histone modifications; Non-coding RNA; Physical exercise; RNA methylation; Skeletal muscle

DOI:  https://doi.org/10.1186/s13072-025-00576-8
Skelet Muscle. 2025 Mar 20. 15(1): 8

Generation of a novel mouse model of nemaline myopathy due to recurrent NEB exon 55 deletion.

Zachary Coulson, Justin Kolb, Nesrin Sabha, Esmat Karimi, Zaynab Hourani, Coen Ottenheijm, Henk Granzier, James J Dowling.

  Biallelic pathogenic variants in the nebulin (NEB) gene lead to the congenital muscle disease nemaline myopathy. In-frame deletion of exon 55 (ΔExon55) is the most common disease-causing variant in NEB. Previously, a mouse model of NebΔExon55 was developed; however, it presented an uncharacteristically severe phenotype with a near complete reduction in Neb transcript expression that is not observed in NEB exon 55 patients. We identified by RNA sequencing that the cause of this unexpectedly severe presentation in mice is the generation of a pseudoexon containing two premature termination codons (and promoting nonsense mediated decay) at the Neb exon 55 deletion site. To prove that this is the cause of the loss of Neb transcript, and to generate a more faithful model of the human disease, we used CRISPR gene editing to remove the pseudoexon sequence and replace it with human intron 54 sequence containing a validated cas9 gRNA protospacer. The resulting "hmz" mice have a significant reduction in pseudoexon formation (93.6% reduction), and a re-introduction of stable Neb transcript expression. This new model has the characteristic features of nemaline myopathy at the physiological, histological, and molecular levels. Importantly, unlike the existing exon 55 deletion mice (which die by age 7 days), it survives beyond the first months and exhibits obvious signs of neuromuscular dysfunction. It thus provides a new, robust model for studying pathomechanisms and developing therapies for NEB related nemaline myopathy.

Keywords:  CRISPR; Nebulin; Nemaline myopathy; Phenotyping; Pseudoexon; Transcript stabilization

DOI:  https://doi.org/10.1186/s13395-025-00378-2
Acta Biomater. 2025 Mar 15. pii: S1742-7061(25)00202-8. [Epub ahead of print]

Injectable Skeletal Muscle Constructs Overexpressing GLUT4 for Type 2 Diabetes Intervention.

Hagit Shoyhet, Yifat Herman Bachinsky, Margarita Bekerman, Lior Debbi, Gali Guterman Ram, Dina Safina, Eddy Karnieli, Shulamit Levenberg.

  Skeletal muscle tissue engineering aims to repair tissue defects caused by injury, cancer, metabolic or neuromuscular disease. The need for invasive implantation techniques often limits the implantation of large tissue constructs or repeated treatments. Recent studies have reported on the development of injectable scaffolds for tissue engineering; however, fabrication of skeletal muscle tissue is particularly challenging due to the large size of human myotubes and the required mechanical properties. This work developed a collagen-based shape-memory scaffold supportive of skeletal muscle tissue growth and differentiation in vitro and maintained shape post-injection in vivo. The injectable engineered muscle construct was intramuscularly delivered via a syringe needle and integrated successfully with the native muscle tissue. We demonstrated the system's potential on a Type 2 diabetes mouse model. A prominent early sign of type 2 diabetes is the reduction in GLUT4 expression and translocation in skeletal muscle; therefore, based on a previous work published by our group, we created injectable GLUT4-overexpressing muscle constructs. Following injection, GLUT4 overexpressing skeletal muscle tissue retained its shape-memory properties and viability and improved glucose homeostasis in the diabetic mice. This work demonstrated successful minimally invasive delivery of engineered muscle tissue and potential treatment for chronic muscle-related conditions. STATEMENT OF SIGNIFICANCE: Type 2 diabetes is a widespread metabolic disorder characterized by insulin resistance and impaired glucose regulation. This study offers a minimally invasive approach to treatment through the development of an injectable skeletal muscle construct overexpressing GLUT4 to improve glucose homeostasis. Unlike traditional surgical methods, this minimally invasive system employs a collagen-based scaffold with shape-memory properties, enabling effective tissue delivery and integration. Existing therapies are limited in addressing chronic metabolic disorders that require repeated interventions. Our work fills that gap by enhancing muscle function and glucose regulation. The scaffold's unique ability to retain its structure post-injection and support muscle differentiation presents a significant advancement with broad implications for treating metabolic diseases and advancing regenerative medicine.

Keywords:  Injectable scaffold; Shape-memory scaffold; Tissue Engineering; Type II Diabetes; skeletal muscle

DOI:  https://doi.org/10.1016/j.actbio.2025.03.029
Diabetes Technol Ther. 2025 Mar;27(S1): S126-S140

Advances in Exercise and Nutrition as Therapy in Diabetes.

Dessi P Zaharieva, Dorsa Shakeri, Lauren V Turner, Michael C Riddell.

DOI: https://doi.org/10.1089/dia.2025.8809.dpz
Mamm Genome. 2025 Mar 18.

Rat models of musculoskeletal lysosomal storage disorders and their role in pre-clinical evaluation of gene therapy approaches.

Sara Marcó, Sergio Muñoz, Fatima Bosch, Veronica Jimenez.

  Mice have been a cornerstone of biomedical research for decades for studying a wide range of biological processes, disease mechanisms, and the assessment of therapies. Moreover, mice present several practical advantages such as small size, low cost and ease of genetic manipulation. While mice offer numerous benefits, for certain disease areas, rat models provide a closer representation of human disease progression, offering better insights for translational research and therapeutic development. This closer resemblance is particularly important for research focusing on diseases involving the cardiovascular and musculoskeletal system. In rats, the pathophysiology of these diseases mirrors the clinical alterations observed in humans. This review focuses on the key phenotypic differences between mouse and rat models of lysosomal storage disorders that specifically manifest with cardiac, skeletal muscle, and bone and joint involvement (Pompe and Danon diseases, and Maroteaux-Lamy and Morquio A syndromes). Furthermore, we discuss the therapeutic potential of various adeno-associated viral vector-mediated gene therapies that have been evaluated in these rat models, highlighting their contributions to advancing treatment options for these debilitating conditions.

Keywords:  AAV vectors; Danon disease; Lysosomal storage disorders; Maroteaux-Lamy syndrome; Morquio A syndrome; Pompe disease; Rat model

DOI:  https://doi.org/10.1007/s00335-025-10121-3
NPJ Syst Biol Appl. 2025 Mar 17. 11(1): 27

A molecular systems architecture of neuromuscular junction in amyotrophic lateral sclerosis.

V A Shiva Ayyadurai, Prabhakar Deonikar, Roger D Kamm.

A molecular systems architecture is presented for the neuromuscular junction (NMJ) in order to provide a framework for organizing complexity of biomolecular interactions in amyotrophic lateral sclerosis (ALS) using a systematic literature review process. ALS is a fatal motor neuron disease characterized by progressive degeneration of the upper and lower motor neurons that supply voluntary muscles. The neuromuscular junction contains cells such as upper and lower motor neurons, skeletal muscle cells, astrocytes, microglia, Schwann cells, and endothelial cells, which are implicated in pathogenesis of ALS. This molecular systems architecture provides a multi-layered understanding of the intra- and inter-cellular interactions in the ALS neuromuscular junction microenvironment, and may be utilized for target identification, discovery of single and combination therapeutics, and clinical strategies to treat ALS.

DOI: https://doi.org/10.1038/s41540-025-00501-5
Nat Commun. 2025 Mar 17. 16(1): 2614

MyoD1 localization at the nuclear periphery is mediated by association of WFS1 with active enhancers.

Konstantina Georgiou, Fatih Sarigol, Tobias Nimpf, Christian Knapp, Daria Filipczak, Roland Foisner, Nana Naetar.

Spatial organization of the mammalian genome influences gene expression and cell identity. While association of genes with the nuclear periphery is commonly linked to transcriptional repression, also active, expressed genes can localize at the nuclear periphery. The transcriptionally active MyoD1 gene, a master regulator of myogenesis, exhibits peripheral localization in proliferating myoblasts, yet the underlying mechanisms remain elusive. Here, we generate a reporter cell line to demonstrate that peripheral association of the MyoD1 locus is independent of mechanisms involved in heterochromatin anchoring. Instead, we identify the nuclear envelope transmembrane protein WFS1 that tethers MyoD1 to the nuclear periphery. WFS1 primarily associates with active distal enhancer elements upstream of MyoD1, and with a subset of enhancers genome-wide, which are enriched in active histone marks and linked to expressed myogenic genes. Overall, our data identify a mechanism involved in tethering regulatory elements of active genes to the nuclear periphery.

DOI: https://doi.org/10.1038/s41467-025-57758-x