Biology subjects

Goljanek-Whysall, K.

Publications and source records attributed to Goljanek-Whysall, K..

18 recordsLinked to original sources

bioRxiv2026

Pathological musculoskeletal characterisation of a new model of spontaneous OA in CD1 mice.

Osteoarthritis (OA) is a whole joint disease involving pathological changes in cartilage, synovium, ligaments, menisci and periarticular muscle. This study provides a comprehensive musculoskeletal characterisation of spontaneous OA in male CD1 mice to evaluate their suitability as a model of naturally occurring disease. Knee joints from 3-4 and 6-8 month old mice were analysed histologically, OARSI scoring and immunohistochemistry for markers of chondrogenesis and endochondral ossification. Quadriceps and gastrocnemius muscles were examined for fibre cross sectional area. CD1 mice displayed mild OA at 3-4 months, progressing to moderate to severe disease by 6-8 months. Cartilage loss, synovial hyperplasia and fibrosis increased across compartments. Anterior cruciate and collateral ligaments, and medial meniscus exhibited marked pathological remodelling, including proteoglycan rich rounded cell regions and evidence of endochondral ossification with increased COL2, SOX9, RUNX2 and ASPN expression. Gastrocnemius muscle showed significant atrophy at 6-8 months, correlating with OA severity, whereas quadriceps atrophy was not significant. These findings establish CD1 mice as a robust spontaneous OA model that recapitulates the multi-tissue complexity of human disease. Because CD1 mice are globally available, cost-effective, genetically diverse and frequently, this model offers a practical and translationally relevant platform for investigating whole-joint organ mechanisms of OA progression and for evaluating therapies aimed at modifying disease across the entire joint.

pathology↗

bioRxiv2026

Peroxiredoxin 6 limits mitochondrial peroxidation to prevent mitochondrial ER contact site assembly and inflammatory signalling following adaptive stress

Peroxiredoxin 6 (PRDX6) is a multifunctional enzyme with peroxidase, calcium independent phospholipase A2 (aiPLA2) and lysophospatidylcholine acyltransterase (LPCAT) activities. Although PRDX6 can repair peroxidised phospholipids and help prevent ferroptosis, its role in the adaptive response to physiological oxidative stress remains unclear. In this study PRDX6 function was investigated using myoblasts exposed to an acute low concentration of H2O2 and Caenorhabditis elegans subjected to a swimming intervention. Mild oxidative stress promoted myogenesis and mitochondrial turnover in myoblasts, while exercise enhanced activity and longevity in C. elegans. The adaptive responses were associated with increased mitochondrial localisation of PRDX6. In contrast, loss of PRDX6 under mild stress conditions resulted in increased mitochondrial lipid peroxidation, enhanced mitochondrial ER contact sites (MERCS), mitochondrial calcium accumulation, release of mitochondrial DNA and activation of innate immune signalling pathways. Similar phenotypes were induced by the ferroptosis activator erastin and rescued by the lipid peroxyl scavenger Ferrostatin-1, indicating lipid peroxidation was the key triggering event. Furthermore, inhibition of mitochondrial calcium uptake in C. elegans prevented calcium overload and attenuated inflammatory signalling. Together, the results identify PRDX6 as a conserved regulator of mitochondrial adaptation to physiological oxidative stress, functioning to limit mitochondrial lipid peroxidation and prevent excessive MERCS assembly, mitochondrial calcium dysregulation and inflammatory activation.

cell biology↗

bioRxiv2025

Exercise Related microRNAs in C. elegans Regulate Calcium Homeostasis and Mitochondrial Dynamics: Conserved pathways, Divergent mircoRNAs

Exercise can help mitigate age-related muscle atrophy, promoting mitochondrial function, Ca2+ homeostasis and regulating gene expression. MicroRNAs (miRs) are crucial post-transcriptional regulators of gene expression, fine tuning protein levels to maintain cellular homeostasis. In C. elegans, a 5-day swimming regimen increased mitochondrial content, lifespan and fitness. Small RNA sequencing identified exercise specific miRs, including increased levels of cel-miR-57-5p and cel-miR-249-3p, and decreased cel-miR-72-3p and cel-miR-77-5p. mir-57 and mir-249 mutant strains had enhanced fertility, survival and lifespan, whereas mir-72 and mir-77 mutant strains had diminished fertility, survival and lifespan. Interestingly both miR-77 and mir-249 mutant strains had disrupted mitochondrial morphology and reduced fitness following exercise. The exercise related miRs identified in C. elegans did not have conserved mammalian orthologs. Exercise regulated mammalian miRs were identified from the literature including mmu-miR-181a-5p, mmu-miR-199a-5p and mmu-miR-378a-3p. Treatment of murine myoblasts with mmu-miR-181a-5p and mmu-miR-378a-3p enhanced mitochondrial content, autophagy markers and myogenesis, while mmu-miR-199a-5p impaired these processes. Exercise related miRs identified in C. elegans target genes regulating Ca2+ homeostasis such as ipp-5 (inositol Polyphosphate-5-phosphatase), sca-1 (Ca2+ transporting ATPase) and ncx-2 (mitochondrial Na+/Ca2+ antiporter). It was also confirmed that mmu-miR181a-5p (miR181) targets Inpp5a and antogmiR-181 (AM181) treatment decreased Ca2+ handling in myotubes. Similarly, mmu-miR-378a-3p and cel-miR-249-3p target Kinase Suppressor of Ras (Ksr1)/ksr-2, involved in the MAPK pathway. Despite direct conservation of exercise related miRs from nematodes to mammals there are common regulatory pathways, contributing to exercise-induced adaptations. Graphical abstractThe exercise related microRNAs (cel-miR-77-5p and cel-miR-249-3p) identified in C. elegans following a 5-day swimming protocol are not conserved in mammalians. However, the microRNAs identified share common gene targets regulating Ca2+ homeostasis and mitochondrial function, with previously identified exercise related microRNAs in murine models. The results highlight conserved regulatory adaptive mechanisms in response to exercise. O_FIG O_LINKSMALLFIG WIDTH=175 HEIGHT=200 SRC="FIGDIR/small/653755v2_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@1da431forg.highwire.dtl.DTLVardef@6cdb70org.highwire.dtl.DTLVardef@ba9d76org.highwire.dtl.DTLVardef@1b7b481_HPS_FORMAT_FIGEXP M_FIG C_FIG

molecular biology↗

bioRxiv2025

PERK orchestrates MERCS formation and mitochondrial remodelling promoting physiological adaptations during adaptive UPR signalling

The transfer of information and metabolites between mitochondria and the ER is mediated by mitochondria-ER contact sites (MERCS), facilitating adaptations following changes in cellular homeostasis. MERCS are dynamic structures, essential for maintaining cellular homeostasis through modulation of calcium transfer, redox signalling, lipid transfer, autophagy and mitochondrial dynamics. Acute ER stress in myoblasts promoted myogenesis that required the PERK arm of the UPRER for increased MERCS assembly, mitochondrial turnover and function. Similarly, induction of acute UPRER during early development in C. elegans resulted in increased lifespan and healthspan. Adaptive UPRER signalling in myoblasts and C. elegans, increased MERCS assembly and activated autophagy, ultimately promoting mitochondrial remodelling. Adaptations were dependent on the developmental stage, as treatment of myotubes or adult C. elegans resulted in a maladaptive response. The results identify that PERK is required for increased mitochondrial ER communication in response to adaptive UPR signalling, promoting mitochondrial remodelling and improved physiological function. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=172 SRC="FIGDIR/small/633960v1_ufig1.gif" ALT="Figure 1"> View larger version (58K): org.highwire.dtl.DTLVardef@66c0f2org.highwire.dtl.DTLVardef@57814org.highwire.dtl.DTLVardef@10e87d5org.highwire.dtl.DTLVardef@f7b69e_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2025

miR-379-3p counteracts cancer cachexia through regulation of pyrimidinergic receptor, mitochondrial stress and interferon response.

Cancer cachexia is a highly prevalent wasting syndrome in cancer patients. Inflammation is hallmarks of symptomatic cachexia, however early stages of cachexia are not well understood, including differences between biological sexes. In a mouse model of early cachexia, muscle from males showed strong mitochondrial defects, whereas females were characterized by inflammatory and stress response. We demonstrate a novel link between the increase in purinergic receptor P26Y, and dysregulated Ca2+ homeostasis, mitochondrial dysfunction and damage, and inflammation during early stages of cancer cachexia. Low levels of miR-379-3p were associated with poor survival of patients with lung cancer. Restoring miR-379-3p levels in mice prevented loss of muscle mass and function. miR-379-3p targeted P2r6y and restored mitochondrial content and function, inhibited type II interferon response, and regulated the expression of Ca2+-related and apoptotic markers. This supports miR-379-3p as a hub regulating multiple processes underlying cachexia and represent a therapeutic target for cancer patients.

cancer biology↗

bioRxiv2024

microRNA-1 Regulates Metabolic Flexibility in Skeletal Muscle via Pyruvate Metabolism

MicroRNA-1 (miR-1) is the most abundant miRNA in adult skeletal muscle. To determine the function of miR-1 in adult skeletal muscle, we generated an inducible, skeletal muscle-specific miR-1 knockout (KO) mouse. Integration of RNA-sequencing (RNA-seq) data from miR-1 KO muscle with Argonaute 2 enhanced crosslinking and immunoprecipitation sequencing (AGO2 eCLIP-seq) from human skeletal muscle identified miR-1 target genes involved with glycolysis and pyruvate metabolism. The loss of miR-1 in skeletal muscle induced cancer-like metabolic reprogramming, as shown by higher pyruvate kinase muscle isozyme M2 (PKM2) protein levels, which promoted glycolysis. Comprehensive bioenergetic and metabolic phenotyping combined with skeletal muscle proteomics and metabolomics further demonstrated that miR-1 KO induced metabolic inflexibility as a result of pyruvate oxidation resistance. While the genetic loss of miR-1 reduced endurance exercise performance in mice and in C. elegans, the physiological down-regulation of miR-1 expression in response to a hypertrophic stimulus in both humans and mice causes a similar metabolic reprogramming that supports muscle cell growth. Taken together, these data identify a novel post-translational mechanism of adult skeletal muscle metabolism regulation mediated by miR-1.

physiology↗

bioRxiv2024

Peroxiredoxin 2 Regulates DAF-16/FOXO Mediated Mitochondrial Remodelling in Response to Exercise that is Disrupted in Ageing

Ageing is associated with mitochondrial dysfunction and increased oxidative stress. Exercise generates endogenous reactive oxygen species (ROS) and promotes rapid mitochondrial remodelling. We investigated the role of Peroxiredoxin 2 (PRDX-2) in mitochondrial adaptations to exercise and ageing using Caenorhabditis elegans as a model system. PRDX-2 was required for the mitochondrial remodelling in response to exercise mediated by DAF-16 nuclear localisation. Employing an acute exercise and recovery cycle, we demonstrated exercise-induced mitochondrial ER contact sites (MERCS) assembly and mitochondrial remodelling dependent on PRDX-2 and DAF-16 signalling. There was increased mitochondrial fragmentation, elevated ROS and an altered redox state of PRDX-2, concomitant with impaired DAF-16 nuclear localisation during ageing. Similarly, the prdx-2 mutant strain exhibited increased mitochondrial fragmentation and a failure to activate DAF-16 required for mitochondrial fusion. Collectively, our data highlight the critical role of PRDX-2 in orchestrating mitochondrial remodelling in response to a physiological stress by regulating DAF-16 nuclear localisation. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=95 SRC="FIGDIR/small/593975v2_ufig1.gif" ALT="Figure 1"> View larger version (30K): org.highwire.dtl.DTLVardef@50b94forg.highwire.dtl.DTLVardef@1b62d31org.highwire.dtl.DTLVardef@1511d0eorg.highwire.dtl.DTLVardef@4a9b6d_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LIExercise generates ROS and promotes mitochondrial remodelling dependent on DAF-16. C_LIO_LIExercise induces mitochondrial ER contact site assembly and mitochondrial dynamics. C_LIO_LIAgeing and loss of PRDX-2 results in disrupted mitochondrial fusion. C_LIO_LIThe redox state of PRDX-2 determines appropriate DAF-16 nuclear localisation. C_LI

molecular biology↗

bioRxiv2024

Unveiling Ageing-Associated and Caloric Restriction-Associated Changes in miRNA Expression in Rat Skeletal Muscle and the Mechanisms Mediating their Effects on Muscle Cell Function

The mechanisms underlying skeletal muscle ageing, whilst poorly understood, are thought to involve dysregulated micro (mi)RNA expression. Using young and aged rat skeletal muscle tissue, we applied high-throughput RNA sequencing to comprehensively study alterations in miRNA expression occurring with age, as well as the impact of caloric restriction (CR) on these changes. Furthermore, the function of the proteins targeted by these age- and CR-associated miRNAs was ascertained. Numerous known and novel age-associated miRNAs were identified of which CR normalised 45.5% to youthful levels. Our results suggested miRNAs upregulated with age to downregulated proteins involved in muscle tissue development and metabolism, as well as longevity pathways, such as AMPK and autophagy. Furthermore, our results found miRNAs downregulated with age to upregulate pro-inflammatory proteins, particularly those involved in innate immunity and the complement and coagulation cascades. Interestingly, CR was particularly effective at normalising miRNAs upregulated with age, rescuing their associated protein coding genes but was less effective at rescuing anti-inflammatory miRNAs downregulated with age. Lastly, the effects of a specific miRNA, miR-96-5p, identified by our analysis to be upregulated with age, were studied in culture C2C12 myoblasts. We demonstrated miR-96-5p to decrease cell viability and markers of mitochondrial biogenesis, myogenic differentiation and autophagy. Overall, our results provide useful information regarding how miRNA expression changes in skeletal muscle, as well as the consequences of these changes and how they are ameliorated by CR.

molecular biology↗

bioRxiv2024

Unravelling the Transcriptomic Symphony of Sarcopenia: Key Pathways and Hub Genes Altered by Muscle Ageing and Caloric Restriction Revealed by RNA Sequencing

Sarcopenia is a disease involving extensive loss of muscle mass and strength with age and is a major cause of disability and accidents in the elderly. Mechanisms purported to be involved in muscle ageing and sarcopenia are numerous but poorly understood, necessitating deeper study. Hence, we employed high-throughput RNA sequencing to explicate the global changes in protein-coding gene expression occurring in skeletal muscle with age. Caloric restriction (CR) is a proven prophylactic intervention against sarcopenia. Therefore, total RNA was isolated from the muscle tissue of both rats fed ad libitum and CR rats. Collected data were subjected to Gene Ontology, pathway, co-expression, and interaction network analyses. This revealed the functional pathways most activated by both ageing and CR, as well as the key "hub" proteins involved in their activation. RNA-seq revealed 442 protein-coding genes to be upregulated and 377 to be downregulated in aged muscle, compared to young muscle. Upregulated genes were commonly involved in protein folding and the immune response; meanwhile, downregulated genes were often related to developmental biology. CR was found to suppress 69.7% and rescue 57.8% of the genes found to be upregulated and downregulated in aged muscle, respectively. In addition, CR uniquely upregulated 291 and downregulated 304 protein-coding genes. Hub genes implicated in both ageing and CR included Gc, Plg, Irf7, Ifit3, Usp18, Rsad2, Blm and RT1-A2, whilst those exclusively implicated in CR responses included Alb, Apoa1, Ambp, F2, Apoh, Orm1, Mx1, Oasl2 and Rtp4. Hub genes involved in ageing but unaffected by CR included Fgg, Fga, Fgb and Serpinc1. In conclusion, this comprehensive RNA sequencing study highlighted gene expression patterns, hub genes and signalling pathways most affected by ageing in skeletal muscle. This data may provide the initial evidence for several targets for therapeutic interventions against sarcopenia.

genomics↗

bioRxiv2023

Lifelong dietary protein restriction accelerates skeletal muscle loss and reduces muscle fibre size by impairing proteostasis and mitochondrial homeostasis

The early life environment significantly affects the development of age-related skeletal muscle disorders. However, the long-term effects of lactational protein restriction on skeletal muscle are still poorly defined. Our study revealed that male mice nursed by dams fed a low-protein diet during lactation exhibited skeletal muscle growth restriction. This was associated with a dysregulation in the expression levels of genes related to the ribosome, mitochondria and skeletal muscle development. We reported that lifelong protein restriction accelerated loss of type-IIa muscle fibres and reduced muscle fibre size by impairing mitochondrial homeostasis and proteostasis at 18 months of age. However, feeding a normal-protein diet following lactational protein restriction prevented accelerated fibre loss and fibre size reduction in later life. These findings provide novel insight into the mechanisms by which lactational protein restriction hinders skeletal muscle growth and includes evidence that lifelong dietary protein restriction accelerated skeletal muscle loss in later life.

physiology↗

bioRxiv2023

The effect of lactational low protein diet on skeletal muscle during adulthood and ageing in male and female mouse offspring

Sarcopenia is characterised by loss of skeletal muscle mass and function associated with a reduction in muscle fibres. External factors, like exercise and diet, can also influence skeletal muscle mass and contribute to muscle fibre loss. Maternal programming refers to the effect of maternal environmental factors such as nutrition that lead to phenotypic changes in the offspring. Maternal malnutrition has been linked to a reduction in body weight and impaired development of skeletal muscle of the offspring; however, there are no studies that reported the long-term effect of maternal low protein diet on the ageing of skeletal muscles. This study aimed to examine how maternal protein deficiency during lactation affects skeletal muscle development and ageing in the offspring. Pups born from normally fed mothers were lactated by low protein fed mothers. Post-weaning, mice were either maintained on a low protein diet (LPD) or switched to normal protein diet (NPD). Pups born from normally fed mothers and maintained on NPD during lactation and afterwards were used as control. In males, the diet mainly affected the size of the myofibres without major effect on fibre number and led to a reduced grip strength of ageing mice (24 months). Female mice had a lower body and muscle weight at weaning but caught up with control mice at 3 months. During ageing, muscle weight, myofibre number and survival rate of female pups were significantly affected. These findings highlight longitudinal animal research for nutritional programming and the importance of sexual dimorphism in response to challenges. HighlightsO_LIPostnatal low protein diet significantly decreases the survival rate of female but not male mice. C_LIO_LIDuring ageing, female mice fed a low protein diet during lactation have lower muscle weight. C_LIO_LIDuring ageing, female mice fed a low protein diet postnatally maintain their myofibre number. C_LIO_LIMale mice fed a low protein diet postnatally have lower body weight and muscle weight throughout their lifespan. C_LIO_LILow protein diet affects myofibres size of TA muscle of male but not female mice at 3 months of age however this effect is lost during ageing. C_LI

physiology↗

bioRxiv2022

Peroxiredoxin 2 is required for the redox mediated adaptation to exercise

Exercise generates a site-specific increase in Reactive Oxygen Species (ROS) within muscle required for a beneficial adaptive response by activation of specific signalling pathways. Here, we demonstrate that Peroxiredoxin 2 (Prdx2), an abundant cytoplasmic 2-Cys peroxiredoxin, is required for the adaptive beneficial hormesis response to H2O2. A short bolus addition of H2O2 increases mitochondrial capacity and improves myogenesis of cultured myoblasts, this beneficial adaptive response was suppressed in myoblasts with decreased expression of cytoplasmic Prdxs. A swimming exercise protocol in C. elegans increased mitochondrial content, fitness, survival and longevity in wild type (N2) worms. In contrast, prdx-2 mutant worms had decreased fitness, disrupted mitochondria, reduced survival and lifespan following exercise. Global proteomics following exercise identified distinct changes in the proteome of N2 and prdx-2 mutants. Furthermore, a redox proteomic approach to quantify reversible oxidation of individual Cysteine residues revealed a relatively more oxidised redox state following exercise in the prdx-2 mutants. Our results demonstrate that conserved cytoplasmic 2-Cys Peroxiredoxins are required for the beneficial adaptive response to a physiological stress.

molecular biology↗

bioRxiv2022

Postnatal protein intake as a determinant of skeletal muscle structure and function in mice - a pilot study

Sarcopenia is characterised by an age-related decrease in the number of muscle fibres and additional weakening of the remaining fibres, resulting in a reduction in muscle mass and function. Many studies associate poor maternal nutrition during gestation and/or lactation with altered skeletal muscle homeostasis in the offspring and the development of sarcopenia. The aim of this study was to determine whether the musculoskeletal physiology in offspring born to mouse dams fed a low-protein diet during pregnancy was altered and whether any physiological changes could be modulated by the nutritional protein content in early postnatal stages. Thy1-YFP female mice were fed ad libitum on either a normal (20%) or a low-protein (5%) diet. Newborn pups were cross-fostered to different lactating dams (maintained on 20% or 5% diet) to generate 3 groups analysed at weaning (21 days): Normal-to-Normal (NN), Normal-to-Low (NL) and Low-to-Normal (LN). Further offspring were maintained ad libitum on the same diet as during lactation until 12 weeks of age creating another 3 groups (NNN, NLL, LNN). Mice on a low protein diet postnatally (NL, NLL) exhibited a significant reduction in body and muscle weight persisting up to 12 weeks, unlike mice on a low protein diet only prenatally (LN, LNN). Muscle fibre size was reduced in mice from the NL but not LN group, showing recovery at 12 weeks of age. Muscle force was reduced in NLL mice, concomitant with changes in the NMJ site and changes in atrophy-related and myosin genes. In addition, CT scans of mouse tibiae at 12 weeks of age revealed changes in bone mass and morphology, resulting in a higher bone mass in the NLL group than the control NNN group. Finally, changes in the expression of miR-133 in the muscle of NLL mice suggest a regulatory role for this microRNA in muscle development in response to postnatal diet changes. Overall, this data shows that a low maternal protein diet and early postnatal life low-protein intake in mice can impact skeletal muscle physiology and function in early life while postnatal low protein diet favors bone integrity in adulthood.

physiology↗

bioRxiv2022

Major Histocompatibility Complex (MHC) I-induced Endoplasmic Reticulum (ER) Stress mediates the secretion of pro-inflammatory muscle-derived cytokines

Major histocompatibility complex (MHC) I is an important component of intracellular antigen presentation. However, improper expression of MHC I upon the cell surface has been associated with several autoimmune diseases. Myositis is a rare acquired autoimmune diseases which targets skeletal muscle, and MHC I overexpression on the surface of muscle fibres and immune cell infiltration are clinical hallmarks. MHC I overexpression may have an important pathogenic role, mediated by the activation of the endoplasmic reticulum (ER) stress response. Given the evidence that muscle is a diverse source of cytokines, we aimed to investigate whether MHC I overexpression can modify the profile of muscle-derived cytokines and what role the ER stress pathway may play. Using C2C12 myoblasts we overexpressed MHC I with a H-2kb vector in the presence or absence of salubrinal an ER stress pathway modifying compound. MHC I overexpression induced ER stress pathway activation and elevated cytokine gene expression. MHC I overexpression caused significant release of cytokines and chemokines, which was attenuated in the presence of salubrinal. Conditioned media from MHC I overexpressing cells induced in vitro T-cell chemotaxis, atrophy of healthy myotubes and modified mitochondrial function, features which were attenuated in the presence of salubrinal. Collectively, these data suggest that MHC I overexpression can induce pro-inflammatory cytokine/chemokine release from C2C12 myoblasts, a process which appears to be mediated in-part by the ER stress pathway.

cell biology↗

bioRxiv2021

Small-RNA sequencing reveals altered skeletal muscle microRNAs and snoRNAs signatures in weanling male offspring from mouse dams fed a low protein diet during lactation

Nutrition plays a key role in pre- and postnatal growth of the musculoskeletal system. Maternal diet during gestation and lactation affects the development of skeletal muscles in the offspring and determines muscle health in later life, however, the molecular mechanisms that govern these effects are largely unknown. In this study, we aim to describe the association between maternal low protein diet-induced changes in offspring skeletal muscle and the differential expression (DE) of small non-coding RNAs (sncRNAs). We used a mouse model of maternal protein restriction to characterise the impact of early-life undernutrition on skeletal muscle morphology in male offspring at weaning. Mouse dams were fed either a normal (N, 20%) or a low protein (L, 8%) diet during gestation and newborn pups were cross-fostered to N or L lactating dams, resulting in the generation of NN, NL and LN offspring groups. Total body and tibialis anterior (TA) weights were decreased in NL males but not different in the LN group, as compared to NN, although neonates from low protein fed dams were smaller at birth than those born to dams fed a normal protein. However, histological evaluation of TA muscle revealed reduced muscle fibre size in both groups at the end of lactation. Small RNA-seq analysis demonstrated DE of multiple classes of sncRNAs, including miRs, snoRNAs and snRNAs. Bioinformatic analyses of miRs-15a, -34a, -122 and -199a, in combination with known myomiRs, confirmed their implication in key muscle-specific biological processes and cellular functions and suggest a promising set of miRs in muscle physiology studies. To our knowledge, this is the first comprehensive report for the DE of sncRNAs in nutrition-associated programming of skeletal muscle development, highlighting the need for further research.

molecular biology↗

bioRxiv2021

miR-24:Prdx6 interactions regulate oxidative stress and viability of myogenic progenitors during ageing

microRNAs regulate a myriad of physiological processes, including skeletal muscle regeneration and homeostasis. During ageing, changes in muscle fibre microenvironment contribute to the capability of satellite cells to regenerate the muscle in response to injury and loading stressors. In this study, we isolated murine satellite cells and primary myogenic progenitors from mice and humans to demonstrate that the microRNA miR-24-3p and its target peroxiredoxin 6 (Prdx6) play an important role in muscle regeneration during ageing, regulating satellite cell viability and their differentiation potential. Our results show upregulation of miR-24 during early stages of muscle regeneration in vivo in adult mice, suggesting a potential role of miR-24 at the early stages of muscle injury. On contrary, miR-24 was downregulated during regeneration of muscle of old mice. miR-24 was also downregulated, whereas its target gene Prdx6 was upregulated, in satellite cells isolated from old mice. miR-24 consistently regulated viability and myogenic potential of myogenic progenitors from both humans and old mice, suggesting that changes in miR-24 levels during ageing may contribute to defective early stages of muscle regeneration during ageing through affecting satellite cell viability and myogenic potential. This regulation likely occurs via miR-24 counteracting the generation of reactive oxygen species through Prdx6 de-repression in primary myogenic progenitors isolated from humans and old mice. We propose that downregulation of miR-24 in muscle of old mice following injury may be a protective mechanism against elevated ROS levels to maintain satellite cell viability and myogenic potential, acting through Prdx6 upregulation. However, as miR-24 is a regulator of p16 and p21, this downregulation may lead to increased satellite cell senescence, therefore representing an age-related failed compensatory mechanism.

cell biology↗

bioRxiv2020

Low protein intake compromises the recovery of lactation-induced bone loss in female mouse dams without affecting skeletal muscles.

ABSTRACTLactation-induced bone loss occurs due to high calcium requirements for fetal growth but skeletal recovery is normally achieved promptly post-weaning. Dietary protein is vital for fetus and mother but the effects of protein undernutrition on the maternal skeleton and skeletal muscles is largely unknown. We used mouse dams fed with normal (N, 20%) or low (L, 8%) protein diet during gestation and lactation and maintained on the same diets (NN, LL) or switched from low to normal (LN) during a 28d skeletal restoration period post lactation. Skeletal muscle morphology and neuromuscular junction integrity was not different between any of the groups. However, dams fed the low protein diet showed extensive bone loss by the end of lactation, followed by full skeletal recovery in NN dams, partial recovery in LN and poor bone recovery in LL dams. Primary osteoblasts from low protein diet fed mice showed decreased in vitro bone formation and decreased osteogenic marker gene expression; promoter methylation analysis by pyrosequencing showed no differences in Bmpr1a, Ptch1, Sirt1, Osx and Igf1r osteoregulators, while miR-26a, -34a and -125b expression was found altered in low protein fed mice. Therefore, normal protein diet is indispensable for maternal musculoskeletal health during the reproductive period.Competing Interest StatementThe authors have declared no competing interest.View Full Text

physiology↗

bioRxiv2019

miR-181a Regulates p62/SQSTM1, Parkin and Protein DJ-1 Promoting Mitochondrial Dynamics in Skeletal Muscle Ageing

One of the key mechanisms underlying skeletal muscle functional deterioration during ageing is disrupted mitochondrial dynamics. Regulation of mitochondrial dynamics is essential to maintain a healthy mitochondrial population and prevent the accumulation of damaged mitochondria, however the regulatory mechanisms are poorly understood. We demonstrated loss of mitochondrial content and disrupted mitochondrial dynamics in muscle during ageing concomitant with dysregulation of miR-181a target interactions. Using functional approaches and mitoQc assay, we have established that miR-181a is an endogenous regulator of mitochondrial dynamics through concerted regulation of Park2, p62/SQSTM1 and DJ-1 in vitro. Downregulation of miR-181a with age was associated with an accumulation of autophagy-related proteins and abnormal mitochondria. Restoring miR-181a levels in old mice prevented accumulation of p62, DJ-1 and PARK2, improved mitochondrial quality and muscle function. These results provide physiological evidence for the potential of microRNA-based interventions for age-related muscle atrophy and of wider significance for diseases with disrupted mitochondrial dynamics.\n\n\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=107 SRC=\"FIGDIR/small/805176v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (54K):\norg.highwire.dtl.DTLVardef@1d6d4c7org.highwire.dtl.DTLVardef@12b6940org.highwire.dtl.DTLVardef@10aed74org.highwire.dtl.DTLVardef@6b5b34_HPS_FORMAT_FIGEXP M_FIG C_FIG

physiology↗