bims-moremu 2024-07-07 papers

bims-moremu

Biomed News

on Molecular regulators of muscle mass

Issue of 2024–07–07
twenty-two papers selected by
Anna Vainshtein, Craft Science Inc.

Skeletal muscle BMAL1 is necessary for transcriptional adaptation of local and peripheral tissues in response to endurance exercise training.
Acute microtubule changes linked to DMD pathology are insufficient to impair contractile function or enhance contraction-induced injury in healthy muscle.
DNA methylation of exercise-responsive genes differs between trained and untrained men.
Nicotinamide N-methyltransferase inhibition mimics and boosts exercise-mediated improvements in muscle function in aged mice.
FOXO-regulated DEAF1 controls muscle regeneration through autophagy.
Proteins change when skeletal muscle regenerates.
The impact of aerobic exercise timing on BMAL1 protein expression and antioxidant responses in skeletal muscle of mice.
Preventing loss of sirt1 lowers mitochondrial oxidative stress and preserves C2C12 myotube diameter in an in vitro model of cancer cachexia.
P7C3 ameliorates barium chloride-induced skeletal muscle injury activating transcriptomic and epigenetic modulation of myogenic regulatory factors.
Editorial: Decoding muscle adaptation through skeletal muscle negative data: understanding the signaling factors involved.
Insights into the epitranscriptomic role of N6-methyladenosine on aging skeletal muscle.
Impaired myoblast differentiation and muscle IGF-1 receptor signaling pathway activation after N-glycosylation inhibition.
Systemic Deletion of ARRDC4 Improves Cardiac Reserve and Exercise Capacity in Diabetes.
Cancer Cachexia in STK11/LKB1 -mutated NSCLC is Dependent on Tumor-secreted GDF15.
Skeletal Muscle Proteome Modifications following Antibiotic-Induced Microbial Disturbances in Cancer Cachexia.
MitoNEET preserves muscle insulin sensitivity during iron overload by regulating mitochondrial iron, reactive oxygen species and fission.
Changes in protein fluxes and gene expression in non-injured muscle tissue distant from an acute myotoxic injury in male mice.
Reactive oxygen species in skeletal muscle injury, fatigue, regeneration and ageing: In memory of John Faulkner The role of zinc and matrix metalloproteinases in myofibrillar protein degradation in critical illness myopathy.
Hindlimb immobilization induces insulin resistance and elevates mitochondrial ROS production in the hippocampus of female rats.
A Preclinical Model of Sepsis-Induced Myopathy with Disuse in Mice.
Development of a local controlled release system for therapeutic proteins in the treatment of skeletal muscle injuries and diseases.
Enhancing circulatory myokines and extracellular vesicle uptake with targeted exercise in patients with prostate cancer (the MYEX trial): a single-group crossover study.

Mol Metab. 2024 Jun 29. pii: S2212-8778(24)00111-X. [Epub ahead of print] 101980

Skeletal muscle BMAL1 is necessary for transcriptional adaptation of local and peripheral tissues in response to endurance exercise training.

Mark R Viggars, Hannah E Berko, Stuart J Hesketh, Christopher A Wolff, Miguel A Gutierrez-Monreal, Ryan A Martin, Isabel G Jennings, Zhiguang Huo, Karyn A Esser.

   OBJECTIVE: In this investigation, we addressed the contribution of the core circadian clock factor, BMAL1, in skeletal muscle to both acute transcriptional responses to exercise and transcriptional remodeling in response to exercise training. Additionally, we adopted a systems biology approach to investigate how loss of skeletal muscle BMAL1 altered peripheral tissue homeostasis as well as exercise training adaptations in iWAT, liver, heart, and lung of male mice.
METHODS: Combining inducible skeletal muscle specific BMAL1 knockout mice, physiological testing and standardized exercise protocols, we performed a multi-omic analysis (transcriptomics, chromatin accessibility and metabolomics) to explore loss of muscle BMAL1 on muscle and peripheral tissue responses to exercise.
RESULTS: Muscle-specific BMAL1 knockout mice demonstrated a blunted transcriptional response to acute exercise, characterized by the lack of upregulation of well-established exercise responsive transcription factors including Nr4a3 and Ppargc1a. Six weeks of exercise training in muscle-specific BMAL1 knockout mice induced significantly greater and divergent transcriptomic and metabolomic changes in muscle. Surprisingly, liver, lung, inguinal white adipose and heart showed divergent exercise training transcriptomes with less than 5% of 'exercise-training' responsive genes shared for each tissue between genotypes.
CONCLUSIONS: Our investigation has uncovered the critical role that BMAL1 plays in skeletal muscle as a key regulator of gene expression programs for both acute exercise and training adaptations. In addition, our work has uncovered the significant impact that altered exercise response in muscle and its likely impact on the system plays in the peripheral tissue adaptations to exercise training. Our work also demonstrates that if the muscle adaptations diverge to a more maladaptive state this is linked to increased gene expression signatures of inflammation across many tissues. Understanding the molecular targets and pathways contributing to health vs. maladaptive exercise adaptations will be critical for the next stage of therapeutic design for exercise mimetics.

Keywords:  Circadian biology; Exercise; Inflammation; Metabolism; Signal transduction; Transcription

DOI:  https://doi.org/10.1016/j.molmet.2024.101980
bioRxiv. 2024 Jun 23. pii: 2024.06.19.599775. [Epub ahead of print]

Acute microtubule changes linked to DMD pathology are insufficient to impair contractile function or enhance contraction-induced injury in healthy muscle.

Camilo Vanegas, Jeanine Ursitti, Jacob G Kallenbach, Kaylie Pinto, Anicca Harriot, Andrew K Coleman, Guoli Shi, Christopher W Ward.

Duchenne muscular dystrophy (DMD) is marked by the genetic deficiency of the dystrophin protein in striated muscle whose consequence is a cascade of cellular changes that predispose the susceptibility to contraction injury central to DMD pathology. Recent evidence identified the proliferation of microtubules enriched in post-translationally modified tubulin as a consequence of dystrophins absence that increases the passive mechanics of the muscle fiber and the excess mechanotransduction elicited reactive oxygen species and calcium signals that promote contraction injury. Motivated by evidence that acutely normalizing the disease microtubule alterations reduced contraction injury in murine DMD muscle ( mdx ), here we sought the direct impact of these microtubule alterations independent of dystrophins absence and the multitude of other changes consequent to dystrophic disease. To this end we used acute pharmacologic (epithiolone-D, EpoD; 4 hours) or genetic (vashohibin-2 and small vasohibin binding protein overexpression via AAV9; 2 weeks) strategies to effectively model the proliferation of detyrosination enriched microtubules in the mdx muscle. Quantifying in vivo nerve evoked plantarflexor function we find no alteration in peak torque nor contraction kinetics in WT mice modeling these DMD relevant MT alterations. Quantifying the susceptibility to eccentric contraction injury we show EpoD treatment proffered a small but significant protection from contraction injury while VASH/SVBP had no discernable impact. We conclude that the disease dependent MT alterations act in concert with additional cellular changes to predispose contraction injury in DMD.

DOI: https://doi.org/10.1101/2024.06.19.599775
BMC Biol. 2024 Jul 04. 22(1): 147

DNA methylation of exercise-responsive genes differs between trained and untrained men.

Carla Geiger, Maria Needhamsen, Eric B Emanuelsson, Jessica Norrbom, Karen Steindorf, Carl Johan Sundberg, Stefan M Reitzner, Malene E Lindholm.

   BACKGROUND: Physical activity is well known for its multiple health benefits and although the knowledge of the underlying molecular mechanisms is increasing, our understanding of the role of epigenetics in long-term training adaptation remains incomplete. In this intervention study, we included individuals with a history of > 15 years of regular endurance or resistance training compared to age-matched untrained controls performing endurance or resistance exercise. We examined skeletal muscle DNA methylation of genes involved in key adaptation processes, including myogenesis, gene regulation, angiogenesis and metabolism.
RESULTS: A greater number of differentially methylated regions and differentially expressed genes were identified when comparing the endurance group with the control group than in the comparison between the strength group and the control group at baseline. Although the cellular composition of skeletal muscle samples was generally consistent across groups, variations were observed in the distribution of muscle fiber types. Slow-twitch fiber type genes MYH7 and MYL3 exhibited lower promoter methylation and elevated expression in endurance-trained athletes, while the same group showed higher methylation in transcription factors such as FOXO3, CREB5, and PGC-1α. The baseline DNA methylation state of those genes was associated with the transcriptional response to an acute bout of exercise. Acute exercise altered very few of the investigated CpG sites.
CONCLUSIONS: Endurance- compared to resistance-trained athletes and untrained individuals demonstrated a different DNA methylation signature of selected skeletal muscle genes, which may influence transcriptional dynamics following a bout of acute exercise. Skeletal muscle fiber type distribution is associated with methylation of fiber type specific genes. Our results suggest that the baseline DNA methylation landscape in skeletal muscle influences the transcription of regulatory genes in response to an acute exercise bout.

Keywords:  DNA methylation; Enzymatic methyl sequencing; Epigenomics; Exercise; Gene expression; Training

DOI:  https://doi.org/10.1186/s12915-024-01938-6
Sci Rep. 2024 Jul 05. 14(1): 15554

Nicotinamide N-methyltransferase inhibition mimics and boosts exercise-mediated improvements in muscle function in aged mice.

Andrea L Dimet-Wiley, Christine M Latham, Camille R Brightwell, Harshini Neelakantan, Alexander R Keeble, Nicholas T Thomas, Haley Noehren, Christopher S Fry, Stanley J Watowich.

  Human hallmarks of sarcopenia include muscle weakness and a blunted response to exercise. Nicotinamide N-methyltransferase inhibitors (NNMTis) increase strength and promote the regenerative capacity of aged muscle, thus offering a promising treatment for sarcopenia. Since human hallmarks of sarcopenia are recapitulated in aged (24-month-old) mice, we treated mice from 22 to 24 months of age with NNMTi, intensive exercise, or a combination of both, and compared skeletal muscle adaptations, including grip strength, longitudinal running capacity, plantarflexor peak torque, fatigue, and muscle mass, fiber type, cross-sectional area, and intramyocellular lipid (IMCL) content. Exhaustive proteome and metabolome analyses were completed to identify the molecular mechanisms underlying the measured changes in skeletal muscle pathophysiology. Remarkably, NNMTi-treated aged sedentary mice showed ~ 40% greater grip strength than sedentary controls, while aged exercised mice only showed a 20% increase relative to controls. Importantly, the grip strength improvements resulting from NNMTi treatment and exercise were additive, with NNMTi-treated exercised mice developing a 60% increase in grip strength relative to sedentary controls. NNMTi treatment also promoted quantifiable improvements in IMCL content and, in combination with exercise, significantly increased gastrocnemius fiber CSA. Detailed skeletal muscle proteome and metabolome analyses revealed unique molecular mechanisms associated with NNMTi treatment and distinct molecular mechanisms and cellular processes arising from a combination of NNMTi and exercise relative to those given a single intervention. These studies suggest that NNMTi-based drugs, either alone or combined with exercise, will be beneficial in treating sarcopenia and a wide range of age-related myopathies.

Keywords:  Aging; Exercise; Muscle; NNMT; Nicotinamide N-methyltransferase; Proteomics

DOI:  https://doi.org/10.1038/s41598-024-66034-9
Autophagy. 2024 Jul 04.

FOXO-regulated DEAF1 controls muscle regeneration through autophagy.

Kah Yong Goh, Wen Xing Lee, Sze Mun Choy, Gopal Krishnan Priyadarshini, Kenon Chua, Qian Hui Tan, Shin Yi Low, Hui San Chin, Chee Seng Wong, Shu-Yi Huang, Nai Yang Fu, Jun Nishiyama, Nathan Harmston, Hong-Wen Tang.

  The commonality between various muscle diseases is the loss of muscle mass, function, and regeneration, which severely restricts mobility and impairs the quality of life. With muscle stem cells (MuSCs) playing a key role in facilitating muscle repair, targeting regulators of muscle regeneration has been shown to be a promising therapeutic approach to repair muscles. However, the underlying molecular mechanisms driving muscle regeneration are complex and poorly understood. Here, we identified a new regulator of muscle regeneration, Deaf1 (Deformed epidermal autoregulatory factor-1) - a transcriptional factor downstream of foxo signaling. We showed that Deaf1 is transcriptionally repressed by FOXOs and that DEAF1 targets to Pik3c3 and Atg16l1 promoter regions and suppresses their expression. Deaf1 depletion therefore induces macroautophagy/autophagy, which in turn blocks MuSC survival and differentiation. In contrast, Deaf1 overexpression inactivates autophagy in MuSCs, leading to increased protein aggregation and cell death. The fact that Deaf1 depletion and its overexpression both lead to defects in muscle regeneration highlights the importance of fine tuning DEAF1-regulated autophagy during muscle regeneration. We further showed that Deaf1 expression is altered in aging and cachectic MuSCs. Manipulation of Deaf1 expression can attenuate muscle atrophy and restore muscle regeneration in aged mice or mice with cachectic cancers. Together, our findings unveil an evolutionarily conserved role for DEAF1 in muscle regeneration, providing insights into the development of new therapeutic strategies against muscle atrophy.

Keywords:  Autophagy; Deaf1; FOXO; cancer cachexia; muscle; sarcopenia

DOI:  https://doi.org/10.1080/15548627.2024.2374693
Lab Anim (NY). 2024 Jul;53(7): 177

Proteins change when skeletal muscle regenerates.

Jorge Ferreira.

DOI: https://doi.org/10.1038/s41684-024-01407-1
Free Radic Res. 2024 Jul 01. 1-12

The impact of aerobic exercise timing on BMAL1 protein expression and antioxidant responses in skeletal muscle of mice.

Lei Xu, Jie Jia, Jingjing Yu, Shudan Miao, Ying Zhang.

  It is well known that the adaptations of muscular antioxidant system to aerobic exercise depend on the frequency, intensity, duration, type of the exercise. Nonetheless, the timing of aerobic exercise, related to circadian rhythms or biological clock, may also affect the antioxidant defense system, but its impact remains uncertain. Bain and muscle ARNT-like 1 (BMAL1) is the core orchestrator of molecular clock, which can maintain cellular redox homeostasis by directly controlling the transcriptional activity of nuclear factor erythroid 2-related factor 2 (NRF2). So, our research objective was to evaluate the impacts of aerobic exercise training at various time points of the day on BMAL1 and NRF2-mediated antioxidant system in skeletal muscle. C57BL/6J mice were assigned to the control group, the group exercising at Zeitgeber Time 12 (ZT12), and the group exercising at ZT24. Control mice were not intervened, while ZT12 and ZT24 mice were trained for four weeks at the early and late time point of their active phase, respectively. We observed that the skeletal muscle of ZT12 mice exhibited higher total antioxidant capacity and lower reactive oxygen species compared to ZT24 mice. Furthermore, ZT12 mice improved the colocalization of BMAL1 with nucleus, the protein expression of BMAL1, NRF2, NAD(P)H quinone oxidoreductase 1, heme oxygenase 1, glutamate-cysteine ligase modifier subunit and glutathione reductase in comparison to those of ZT24 mice. In conclusion, the 4-week aerobic training performed at ZT12 is more effective for enhancing NRF2-mediated antioxidant responses of skeletal muscle, which may be attributed to the specific activation of BMAL1.

Keywords:  BMAL1; Exercise timing; NRF2-mediated antioxidant responses; skeletal muscle

DOI:  https://doi.org/10.1080/10715762.2024.2348789
Physiol Rep. 2024 Jul;12(13): e16103

Preventing loss of sirt1 lowers mitochondrial oxidative stress and preserves C2C12 myotube diameter in an in vitro model of cancer cachexia.

Brian A Hain, Scot R Kimball, David L Waning.

  Cancer cachexia is a multifactorial syndrome associated with advanced cancer that contributes to mortality. Cachexia is characterized by loss of body weight and muscle atrophy. Increased skeletal muscle mitochondrial reactive oxygen species (ROS) is a contributing factor to loss of muscle mass in cachectic patients. Mice inoculated with Lewis lung carcinoma (LLC) cells lose weight, muscle mass, and have lower muscle sirtuin-1 (sirt1) expression. Nicotinic acid (NA) is a precursor to nicotinamide dinucleotide (NAD+) which is exhausted in cachectic muscle and is a direct activator of sirt1. Mice lost body and muscle weight and exhibited reduced skeletal muscle sirt1 expression after inoculation with LLC cells. C2C12 myotubes treated with LLC-conditioned media (LCM) had lower myotube diameter. We treated C2C12 myotubes with LCM for 24 h with or without NA for 24 h. C2C12 myotubes treated with NA maintained myotube diameter, sirt1 expression, and had lower mitochondrial superoxide. We then used a sirt1-specific small molecule activator SRT1720 to increase sirt1 activity. C2C12 myotubes treated with SRT1720 maintained myotube diameter, prevented loss of sirt1 expression, and attenuated mitochondrial superoxide production. Our data provides evidence that NA may be beneficial in combating cancer cachexia by maintaining sirt1 expression and decreasing mitochondrial superoxide production.

Keywords:  cancer cachexia; mitochondria; nicotinic acid; oxidative stress; sirtuin‐1

DOI:  https://doi.org/10.14814/phy2.16103
J Cell Physiol. 2024 Jun 30.

P7C3 ameliorates barium chloride-induced skeletal muscle injury activating transcriptomic and epigenetic modulation of myogenic regulatory factors.

Joung W Kim, Ravikumar Manickam, Puja Sinha, Wanling Xuan, Jian Huang, Kamal Awad, Marco Brotto, Srinivas M Tipparaju.

  Skeletal muscle injury affects the quality of life in many pathologies, including volumetric muscle loss, contusion injury, and aging. We hypothesized that the nicotinamide phosphoribosyltransferase (Nampt) activator P7C3 improves muscle repair following injury. In the present study, we tested the effect of P7C3 (1-anilino-3-(3,6-dibromocarbazol-9-yl) propan-2-ol) on chemically induced muscle injury. Muscle injury was induced by injecting 50 µL 1.2% barium chloride (BaCl2) into the tibialis anterior (TA) muscle in C57Bl/6J wild-type male mice. Mice were then treated with either 10 mg/kg body weight of P7C3 or Vehicle intraperitoneally for 7 days and assessed for histological, biochemical, and molecular changes. In the present study, we show that the acute BaCl2-induced TA muscle injury was robust and the P7C3-treated mice displayed a significant increase in the total number of myonuclei and blood vessels, and decreased serum CK activity compared with vehicle-treated mice. The specificity of P7C3 was evaluated using Nampt+/- mice, which did not display any significant difference in muscle repair capacity among treated groups. RNA-sequencing analysis of the injured TA muscles displayed 368 and 212 genes to be exclusively expressed in P7C3 and Veh-treated mice, respectively. There was an increase in the expression of genes involved in cellular processes, inflammatory response, angiogenesis, and muscle development in P7C3 versus Veh-treated mice. Conversely, there is a decrease in muscle structure and function, myeloid cell differentiation, glutathione, and oxidation-reduction, drug metabolism, and circadian rhythm signaling pathways. Chromatin immunoprecipitation-quantitative polymerase chain reaction (qPCR) and reverse transcription-qPCR analyses identified increased Pax7, Myf5, MyoD, and Myogenin expression in P7C3-treated mice. Increased histone lysine (H3K) methylation and acetylation were observed in P7C3-treated mice, with significant upregulation in inflammatory markers. Moreover, P7C3 treatment significantly increased the myotube fusion index in the BaCl2-injured human skeletal muscle in vitro. P7C3 also inhibited the lipopolysaccharide-induced inflammatory response and mitochondrial membrane potential of RAW 264.7 macrophage cells. Overall, we demonstrate that P7C3 activates muscle stem cells and enhances muscle injury repair with increased angiogenesis.

Keywords:  NAD; angiogenesis; chromatin modifications; injury‐repair; nampt activator; skeletal muscle

DOI:  https://doi.org/10.1002/jcp.31346
Front Physiol. 2024 ;15 1440736

Editorial: Decoding muscle adaptation through skeletal muscle negative data: understanding the signaling factors involved.

Marshall A Naimo, Brandon M Roberts, Stephen E Alway.



Keywords:  adaptive response; biomarkers; exercise; mechanisms and models; negative data; overload; pathways; skeletal muscle quality

DOI:  https://doi.org/10.3389/fphys.2024.1440736
Biomed Pharmacother. 2024 Jul 03. pii: S0753-3322(24)00925-9. [Epub ahead of print]177 117041

Insights into the epitranscriptomic role of N6-methyladenosine on aging skeletal muscle.

Susan Enechojo Ogbe, JiDa Wang, YueXuan Shi, Ying Wang, Zhe Xu, Joseph Kofi Abankwa, Lisa Dal Pozzo, ShuWu Zhao, HuiFang Zhou, YanFei Peng, XiaoQian Chu, XiangLing Wang, YuHong Bian.

  The modification of RNA through the N6-methyladenosine (m6A) has emerged as a growing area of research due to its regulatory role in gene expression and various biological processes regulating the expression of genes. m6A RNA methylation is a post-transcriptional modification that is dynamic and reversible and found in mRNA, tRNA, rRNA, and other non-coding RNA of most eukaryotic cells. It is executed by special proteins known as "writers," which initiate methylation; "erasers," which remove methylation; and "readers," which recognize it and regulate the expression of the gene. Modification by m6A regulates gene expression by affecting the splicing, translation, stability, and localization of mRNA. Aging causes molecular and cellular damage, which forms the basis of most age-related diseases. The decline in skeletal muscle mass and functionality because of aging leads to metabolic disorders and morbidities. The inability of aged muscles to regenerate and repair after injury poses a great challenge to the geriatric populace. This review seeks to explore the m6A epigenetic regulation in the myogenesis and regeneration processes in skeletal muscle as well as the progress made on the m6A epigenetic regulation of aging skeletal muscles.

Keywords:  aging; epigenetics; m(6)A methylation; regeneration; sarcopenia; skeletal muscle

DOI:  https://doi.org/10.1016/j.biopha.2024.117041
FASEB J. 2024 Jul 15. 38(13): e23797

Impaired myoblast differentiation and muscle IGF-1 receptor signaling pathway activation after N-glycosylation inhibition.

Giosuè Annibalini, Laura Di Patria, Giacomo Valli, Matteo Bocconcelli, Roberta Saltarelli, Lorenzo Ferri, Laura Barberi, Fabiana Fanelli, Amelia Morrone, Rita Barone, Renzo Guerrini, Antonio Musarò, Vilberto Stocchi, Elena Barbieri.

  The role of N-glycosylation in the myogenic process remains poorly understood. Here, we evaluated the impact of N-glycosylation inhibition by Tunicamycin (TUN) or by phosphomannomutase 2 (PMM2) gene knockdown, which encodes an enzyme essential for catalyzing an early step of the N-glycosylation pathway, on C2C12 myoblast differentiation. The effect of chronic treatment with TUN on tibialis anterior (TA) and extensor digitorum longus (EDL) muscles of WT and MLC/mIgf-1 transgenic mice, which overexpress muscle Igf-1Ea mRNA isoform, was also investigated. TUN-treated and PMM2 knockdown C2C12 cells showed reduced ConA, PHA-L, and AAL lectin binding and increased ER-stress-related gene expression (Chop and Hspa5 mRNAs and s/uXbp1 ratio) compared to controls. Myogenic markers (MyoD, myogenin, and Mrf4 mRNAs and MF20 protein) and myotube formation were reduced in both TUN-treated and PMM2 knockdown C2C12 cells. Body and TA weight of WT and MLC/mIgf-1 mice were not modified by TUN treatment, while lectin binding slightly decreased in the TA muscle of WT (ConA and AAL) and MLC/mIgf-1 (ConA) mice. The ER-stress-related gene expression did not change in the TA muscle of WT and MLC/mIgf-1 mice after TUN treatment. TUN treatment decreased myogenin mRNA and increased atrogen-1 mRNA, particularly in the TA muscle of WT mice. Finally, the IGF-1 production and IGF1R signaling pathways activation were reduced due to N-glycosylation inhibition in TA and EDL muscles. Decreased IGF1R expression was found in TUN-treated C2C12 myoblasts which was associated with lower IGF-1-induced IGF1R, AKT, and ERK1/2 phosphorylation compared to CTR cells. Chronic TUN-challenge models can help to elucidate the molecular mechanisms through which diseases associated with aberrant N-glycosylation, such as Congenital Disorders of Glycosylation (CDG), affect muscle and other tissue functions.

Keywords:   PMM2 ; IGF1R signaling pathway; congenital disorders of glycosylation; glycosylation; muscle atrophy; myoblast differentiation

DOI:  https://doi.org/10.1096/fj.202400213RR
Circ Res. 2024 Jul 01.

Systemic Deletion of ARRDC4 Improves Cardiac Reserve and Exercise Capacity in Diabetes.

Yoshinobu Nakayama, Satoru Kobayashi, Aliya Masihuddin, Syed Amir Abdali, A M Pramodh Bandara Seneviratne, Sachiyo Ishii, Jun Iida, Qiangrong Liang, Jun Yoshioka.

   BACKGROUND: Exercise intolerance is an independent predictor of poor prognosis in diabetes. The underlying mechanism of the association between hyperglycemia and exercise intolerance remains undefined. We recently demonstrated that the interaction between ARRDC4 (arrestin domain-containing protein 4) and GLUT1 (glucose transporter 1) regulates cardiac metabolism.
OBJECTIVE: To determine whether this mechanism broadly impacts diabetic complications, we investigated the role of ARRDC4 in the pathogenesis of diabetic cardiac and skeletal myopathy.
METHODS AND RESULTS: High glucose promoted translocation of MondoA into the nucleus, which upregulated Arrdc4 transcriptional expression, increased lysosomal GLUT1 trafficking, and blocked glucose transport in cardiomyocytes, forming a feedback mechanism. This role of ARRDC4 was confirmed in human muscular cells from type 2 diabetic patients. Prolonged hyperglycemia upregulated myocardial Arrdc4 expression in multiple types of mouse models of diabetes. We then analyzed hyperglycemia-induced cardiac and skeletal muscle abnormalities in insulin-deficient mice. Hyperglycemia increased advanced glycation end-products and elicited oxidative and endoplasmic reticulum stress leading to apoptosis in the heart and peripheral muscle. However, deletion of Arrdc4 augmented tissue glucose transport and mitochondrial respiration, protecting the heart and muscle from tissue damage. Stress hemodynamic analysis and treadmill exhaustion test uncovered that Arrdc4-knockout mice had greater cardiac inotropic/chronotropic reserve with higher exercise endurance than wild-type (WT) animals under diabetes. While multiple organs were involved in the mechanism, cardiac-specific overexpression (beyond levels observed during diabetes) using adenoassociated virus suggests that high levels of myocardial ARRDC4 have the potential to contribute to exercise intolerance by interfering with cardiac metabolism through its interaction with GLUT1 in diabetes. Importantly, the ARRDC4 mutation mouse line exhibited greater exercise tolerance, showing the potential therapeutic impact on diabetic cardiomyopathy by disrupting the interaction between ARRDC4 and GLUT1.
CONCLUSIONS: ARRDC4 serves as a regulator of hyperglycemia-induced toxicities toward cardiac and skeletal muscle, revealing a new molecular framework that connects hyperglycemia to cardiac/skeletal myopathy to exercise intolerance.

Keywords:  adaptor protein; diabetic cardiomyopathy; energy metabolism; exercise endurance; health

DOI:  https://doi.org/10.1161/CIRCRESAHA.123.323158
bioRxiv. 2024 Jun 17. pii: 2024.06.14.598891. [Epub ahead of print]

Cancer Cachexia in STK11/LKB1 -mutated NSCLC is Dependent on Tumor-secreted GDF15.

Jinhai Yu, Tong Guo, Arun Gupta, Ernesto M Llano, Naureen Wajahat, Sean Slater, Qing Deng, Esra A Akbay, John M Shelton, Bret M Evers, Zhidan Wu, Iphigenia Tzameli, Evanthia Pashos, John D Minna, Puneeth Iyengar, Rodney E Infante.

Cachexia is a wasting syndrome comprised of adipose, muscle, and weight loss observed in cancer patients. Tumor loss-of-function mutations in STK11/LKB1 , a regulator of the energy sensor AMP-activated protein kinase, induce cancer cachexia (CC) in preclinical models and are associated with cancer-related weight loss in NSCLC patients. Here we characterized the relevance of the NSCLC-associated cachexia factor growth differentiation factor 15 (GDF15) in several patient-derived and genetically engineered STK11/LKB1 -mutant NSCLC cachexia lines. Both tumor mRNA expression and serum concentrations of tumor-derived GDF15 were significantly elevated in multiple mice transplanted with patient-derived STK11/LKB1 -mutated NSCLC lines. GDF15 neutralizing antibody administered to mice transplanted with patient- or mouse-derived STK11/LKB1 -mutated NSCLC lines suppressed cachexia-associated adipose loss, muscle atrophy, and changes in body weight. The silencing of GDF15 in multiple human NSCLC lines was also sufficient to eliminate in vivo circulating GDF15 levels and abrogate cachexia induction, suggesting that tumor and not host tissues represent a key source of GDF15 production in these cancer models. Finally, reconstitution of wild-type STK11/LKB1 in a human STK11/LKB1 loss-of-function NSCLC line that normally induces cachexia in vivo correlated with the absence of tumor-secreted GDF15 and rescue from the cachexia phenotype. The current data provide evidence for tumor-secreted GDF15 as a conduit and a therapeutic target through which NSCLCs with STK11/LKB1 loss-of-function mutations promote cachexia-associated wasting.

DOI: https://doi.org/10.1101/2024.06.14.598891
J Proteome Res. 2024 Jul 05. 23(7): 2452-2473

Skeletal Muscle Proteome Modifications following Antibiotic-Induced Microbial Disturbances in Cancer Cachexia.

Mathilde Simonson, Gwendal Cueff, Morgane M Thibaut, Christophe Giraudet, Jérôme Salles, Christophe Chambon, Yves Boirie, Laure B Bindels, Marine Gueugneau, Christelle Guillet.

  Cancer cachexia is an involuntary loss of body weight, mostly of skeletal muscle. Previous research favors the existence of a microbiota-muscle crosstalk, so the aim of the study was to evaluate the impact of microbiota alterations induced by antibiotics on skeletal muscle proteins expression. Skeletal muscle proteome changes were investigated in control (CT) or C26 cachectic mice (C26) with or without antibiotic treatment (CT-ATB or C26-ATB, n = 8 per group). Muscle protein extracts were divided into a sarcoplasmic and myofibrillar fraction and then underwent label-free liquid chromatography separation, mass spectrometry analysis, Mascot protein identification, and METASCAPE platform data analysis. In C26 mice, the atrogen mafbx expression was 353% higher than CT mice and 42.3% higher than C26-ATB mice. No effect on the muscle protein synthesis was observed. Proteomic analyses revealed a strong effect of antibiotics on skeletal muscle proteome outside of cachexia, with adaptative processes involved in protein folding, growth, energy metabolism, and muscle contraction. In C26-ATB mice, proteome adaptations observed in CT-ATB mice were blunted. Differentially expressed proteins were involved in other processes like glucose metabolism, oxidative stress response, and proteolysis. This study confirms the existence of a microbiota-muscle axis, with a muscle response after antibiotics that varies depending on whether cachexia is present.

Keywords:  antibiotics; cancer cachexia; microbial disturbances; proteomics; skeletal muscle

DOI:  https://doi.org/10.1021/acs.jproteome.4c00143
FEBS J. 2024 Jun 30.

MitoNEET preserves muscle insulin sensitivity during iron overload by regulating mitochondrial iron, reactive oxygen species and fission.

Eddie Tam, Khang Nguyen, Hye Kyoung Sung, Gary Sweeney.

  Iron overload (IO) is known to contribute to metabolic dysfunctions such as type 2 diabetes and insulin resistance. Using L6 skeletal muscle cells overexpressing the CDGSH iron-sulfur domain-containing protein 1 (CISD1, also known as mitoNEET) (mitoN) protein, we examined the potential role of MitoN in preventing IO-induced insulin resistance. In L6 control cells, IO resulted in insulin resistance which could be prevented by MitoN as demonstrated by western blot of p-Akt and Akt biosensor cells. Mechanistically, IO increased; mitochondrial iron accumulation, mitochondrial reactive oxygen species (ROS), Fis1-dependent mitochondrial fission, mitophagy, FUN14 domain-containing protein 1 (FUNDC1) expression, and decreased Parkin. MitoN overexpression was able to reduce increases in mitochondrial iron accumulation, mitochondrial ROS, mitochondrial fission, mitophagy and FUNDC1 upregulation due to IO. MitoN did not have any effect on the IO-induced downregulation of Parkin. MitoN alone also upregulated peroxisome proliferator-activated receptor gamma coactivator 1 alpha (PGC1α) protein levels, a master regulator of mitochondrial biogenesis. The use of mitochondrial antioxidant, Skq1, or fission inhibitor, Mdivi-1, prevented IO-induced insulin resistance implying both mitochondrial ROS and fission play a causal role in the development of insulin resistance. Taken together, MitoN is able to confer protection against IO-induced insulin resistance in L6 skeletal muscle cells through regulation of mitochondrial iron content, mitochondrial ROS, and mitochondrial fission.

Keywords:  insulin resistance; iron overload; mitoNEET; mitochondria; mitochondrial dynamics; reactive oxygen species

DOI:  https://doi.org/10.1111/febs.17214
J Physiol. 2024 Jul 05.

Changes in protein fluxes and gene expression in non-injured muscle tissue distant from an acute myotoxic injury in male mice.

Alec Bizieff, Maggie Cheng, Kelvin Chang, Hussein Mohammed, Naveed Ziari, Edna Nyangau, Mark Fitch, Marc K Hellerstein.

  The response to acute myotoxic injury requires stimulation of local repair mechanisms in the damaged tissue. However, satellite cells in muscle distant from acute injury have been reported to enter a functional state between quiescence and active proliferation. Here, we asked whether protein flux rates are altered in muscle distant from acute local myotoxic injury and how they compare to changes in gene expression from the same tissue. Broad and significant alterations in protein turnover were observed across the proteome in the limb contralateral to injury during the first 10 days after. Interestingly, mRNA changes had almost no correlation with directly measured protein turnover rates. In summary, we show consistent and striking changes in protein flux rates in muscle tissue contralateral to myotoxic injury, with no correlation between changes in mRNA levels and protein synthesis rates. This work motivates further investigation of the mechanisms, including potential neurological factors, responsible for this distant effect. KEY POINTS: Previous literature demonstrates that stem cells of uninjured muscle respond to local necrotic muscle tissue damage and regeneration. We show that muscle tissue that was distant from a model of local necrotic damage had functional changes at both the gene expression and the protein turnover level. However, these changes in distant tissue were more pronounced during the earlier stages of tissue regeneration and did not correlate well with each other. The results suggest communication between directly injured tissue and non-affected tissues that are distant from injury, which warrants further investigation into the potential of this mechanism as a proactive measure for tissue regeneration from damage.

Keywords:  in vivo regeneration; mass spectrometry; muscle damage/injury; protein turnover; proteomics; satellite cells; stable isotope labelling

DOI:  https://doi.org/10.1113/JP286307
Free Radic Biol Med. 2024 Jun 27. pii: S0891-5849(24)00539-2. [Epub ahead of print]

Reactive oxygen species in skeletal muscle injury, fatigue, regeneration and ageing: In memory of John Faulkner The role of zinc and matrix metalloproteinases in myofibrillar protein degradation in critical illness myopathy.

Fernando Ribeiro, Xiang Zhang, Ya Wen, Nicola Cacciani, Yvette Hedström, Zhidan Xia, Richard Schulz, Lars Larsson.

  Due to an unexpected activation of different zinc (Zn) transporters in a recent prospective clinical study, we have revisited the role of Zn homeostasis and the activation of matrix metalloproteinases (MMPs) in skeletal muscle exposed to the intensive care unit (ICU) condition (immobilization and mechanical ventilation). ICU patients exposed to 12 days ICU condition were followed longitudinally with six repeated muscle biopsies while they showed a progressive preferential myosin loss, i.e., the hallmark of Critical Illness Myopathy (CIM), in parallel with the activation of Zn-transporters. In this study, we have revisited the expression of Zn-transporters and the activation of MMPs in clinical as well as in experimental studies using an established ICU model. MMPs are a group Zn-dependent endopeptidases which do not only target and cleave extracellular proteins but also intracellular proteins including multiple sarcomeric proteins. MMP-9 is of specific interest since the hallmark of CIM, the preferential myosin loss, has also been reported in dilated cardiomyopathy and coupled to MMP-9 activation. Transcriptional activation of Zn-transporters was observed in both clinical and experimental studies as well as the activation of MMPs, in particular MMP-9, in various limb and respiratory muscles in response to long-term exposure to the ICU condition. The activation of Zn-transporters was paralleled by increased Zn levels in skeletal muscle which in turn showed a negative linear correlation with the preferential myosin loss associated with CIM, offering a potential intervention strategy. Thus, activation of Zn-transporters, increased intramuscular Zn levels, and activation of the Zn-dependent MMPs are forwarded as a probable mechanism involved in CIM pathophysiology. These effects were confirmed in different rat strains subjected to a model of CIM and exacerbated by old age. This is of specific interest since old age and muscle wasting are the two factors most strongly associated with ICU mortality.

Keywords:  Intensive care; Mechanical ventilation; Metallothionein; Myosin; Zinc transporters

DOI:  https://doi.org/10.1016/j.freeradbiomed.2024.06.022
J Appl Physiol (1985). 2024 Jul 04.

Hindlimb immobilization induces insulin resistance and elevates mitochondrial ROS production in the hippocampus of female rats.

Nathan R Kerr, Chandler W Mossman, Chih-Hsuan Chou, Joshua M Bunten, Taylor J Kelty, Thomas E Childs, R Scott Rector, W David Arnold, Laurel A Grisanti, Xiangwei Du, Frank W Booth.

  Alzheimer's Disease (AD) is the 5th leading cause of death in older adults and treatment options are severely lacking. Recent findings demonstrate a strong relationship between skeletal muscle and cognitive function, with evidence supporting that muscle quality and cognitive function are positively correlated in older adults. Conversely, decreased muscle function is associated with a 3-fold increased risk of cognitive decline. Based on these observations, the purpose of this study was to investigate the negative effects of muscle disuse (via a model of hindlimb immobilization (HLI)) on hippocampal insulin sensitivity and mitochondrial function and identify the potential mechanisms involved. HLI for 10 days in 4-month-old female Wistar rats resulted in the following novel findings: 1) hippocampal insulin resistance and deficits in whole body glucose homeostasis, 2) dramatically increased mitochondrial reactive oxygen species (ROS) production in the hippocampus, 3) elevated markers for amyloidogenic cleavage of APP and tau protein in the hippocampus, 4) and reduced BDNF expression. These findings were associated with global changes in iron homeostasis, with muscle disuse producing muscle iron accumulation in association with decreased serum and whole brain iron levels. We report the novel finding that muscle disuse alters brain iron homeostasis and reveal a strong negative correlation between muscle and brain iron content. Overall, HLI-induced muscle disuse has robust negative effects on hippocampal insulin sensitivity and ROS production in association with altered brain iron homeostasis. This work provides potential novel mechanisms that may help explain how loss of muscle function contributes to cognitive decline and AD risk.

Keywords:  Muscle disuse; brain insulin resistance; hippocampus; iron overload; muscle-brain axis

DOI:  https://doi.org/10.1152/japplphysiol.00234.2024
J Vis Exp. 2024 Jun 14.

A Preclinical Model of Sepsis-Induced Myopathy with Disuse in Mice.

Franccesco P Boeno, Diana C Muller, Ali Aldakkan, Zhuoxin Li, Gisienne Reis, Elisabeth R Barton, Orlando Laitano.

Sepsis is a major cause of in-hospital deaths. Improvements in treatment result in a greater number of sepsis survivors. Approximately 75% of the survivors develop muscle weakness and atrophy, increasing the incidence of hospital readmissions and mortality. However, the available preclinical models of sepsis do not address skeletal muscle disuse, a key component for the development of sepsis-induced myopathy. Our objective in this protocol is to provide a step-by-step guideline for a mouse model that reproduces the clinical setting experienced by a bedridden septic patient. Male C57Bl/6 mice were used to develop this model. Mice underwent cecal ligation and puncture (CLP) to induce sepsis. Four days post-CLP, mice were subjected to hindlimb suspension (HLS) for seven days. Results were compared with sham-matched surgeries and/or animals with normal ambulation (NA). Muscles were dissected for in vitro muscle mechanics and morphological assessments. The model results in marked muscle atrophy and weakness, a similar phenotype observed in septic patients. The model represents a platform for testing potential therapeutic strategies for the mitigation of sepsis-induced myopathy.

DOI: https://doi.org/10.3791/66685
Cell Death Dis. 2024 Jul 02. 15(7): 470

Development of a local controlled release system for therapeutic proteins in the treatment of skeletal muscle injuries and diseases.

Rachel Lev, Orit Bar-Am, Galit Saar, Ombretta Guardiola, Gabriella Minchiotti, Eli Peled, Dror Seliktar.

The present study aims to develop and characterize a controlled-release delivery system for protein therapeutics in skeletal muscle regeneration following an acute injury. The therapeutic protein, a membrane-GPI anchored protein called Cripto, was immobilized in an injectable hydrogel delivery vehicle for local administration and sustained release. The hydrogel was made of poly(ethylene glycol)-fibrinogen (PEG-Fibrinogen, PF), in the form of injectable microspheres. The PF microspheres exhibited a spherical morphology with an average diameter of approximately 100 micrometers, and the Cripto protein was uniformly entrapped within them. The release rate of Cripto from the PF microspheres was controlled by tuning the crosslinking density of the hydrogel, which was varied by changing the concentration of poly(ethylene glycol) diacrylate (PEG-DA) crosslinker. In vitro experiments confirmed a sustained-release profile of Cripto from the PF microspheres for up to 27 days. The released Cripto was biologically active and promoted the in vitro proliferation of mouse myoblasts. The therapeutic effect of PF-mediated delivery of Cripto in vivo was tested in a cardiotoxin (CTX)-induced muscle injury model in mice. The Cripto caused an increase in the in vivo expression of the myogenic markers Pax7, the differentiation makers eMHC and Desmin, higher numbers of centro-nucleated myofibers and greater areas of regenerated muscle tissue. Collectively, these results establish the PF microspheres as a potential delivery system for the localized, sustained release of therapeutic proteins toward the accelerated repair of damaged muscle tissue following acute injuries.

DOI: https://doi.org/10.1038/s41419-024-06645-2
BMC Cancer. 2024 Jul 01. 24(1): 784

Enhancing circulatory myokines and extracellular vesicle uptake with targeted exercise in patients with prostate cancer (the MYEX trial): a single-group crossover study.

Jin-Soo Kim, Dennis R Taaffe, Daniel A Galvão, Timothy D Clay, Andrew D Redfern, Elin S Gray, Robert U Newton.

   INTRODUCTION: Physical activity is associated with improved disease progression and cancer-specific survival in patients with prostate cancer (PCa). However, the mechanisms underlying these associations remain unclear, while the relative impact of exercise modes is unknown. This study aims to examine the differential impact of exercise mode on tumour-suppressive skeletal muscle-associated systemic molecules as well as their delivery mechanism. This study will compare the effects of the two main exercise modes, aerobic and resistance, on (1) circulatory myokine levels, (2) skeletal muscle-induced extracellular vesicle abundance and cargo contents, and (3) uptake of extracellular vesicles (EVs) in PCa cells in patients with localised or advanced PCa.
METHODS: A single-group cross-over design will be used for patients at opposite ends of the disease spectrum. A total of 32 patients (localised PCa, n = 16; metastatic castrate-resistant PCa, n = 16) will be recruited while capitalising on two ongoing studies. Ethics amendment has been approved for two ongoing trials to share data, implement the acute exercise sessions, and collect additional blood samples from patients. The patients will undertake two exercise sessions (aerobic only and resistance only) in random order one week apart. Blood will be collected before, after, and 30 min post-exercise. Circulating/EV-contained myokine levels (irisin, IL-6, IL-15, FGF-21, and SPARC) and plasma skeletal muscle-induced EVs will be measured using ELISA and flow cytometry. PCa cell line growth with or without collected plasma will be examined using PCa cell lines (LNCaP, DU-145, and PC-3), while evaluating cellular uptake of EVs. Ethics amendments have been approved for two capitalising studies to share data, implement acute exercise sessions and collect additional samples from the patients.
DISCUSSION: If findings show a differential impact of exercise mode on the establishment of an anti-cancer systemic environment, this will provide fundamental knowledge for developing targeted exercise prescriptions for patients with PCa across different disease stages. Findings will be reported in peer-reviewed publications and scientific conferences, in addition to working with national support groups to translate findings for the broader community.
TRIAL REGISTRATION: The registration for the two capitalising studies are NCT02730338 and ACTRN12618000225213.

Keywords:  Exercise; Extracellular vesicles; Myokines; Prostate cancer

DOI:  https://doi.org/10.1186/s12885-024-12530-0