Biology subjects

Jones, S. W.

Publications and source records attributed to Jones, S. W..

8 recordsLinked to original sources

bioRxiv2026

Infrapatellar Fat Pad Extracellular Vesicles Induce a Pro-Angiogenic VEGFAhigh/BMP4low Switch in Articular Chondrocytes: Implications for Chondrosarcoma

Chondrosarcoma is a hyper-vascularised, chemoresistant cartilage malignancy driven by VEGF-centred angiogenesis, and local adipose depots are increasingly recognised as paracrine drivers of tumour angiogenesis via adipokines and extracellular vesicles (EVs). The infrapatellar fat pad (IFP), an inflammatory adipose depot within the articular joint in direct cartilage contact, is a key local source of adipose-derived EVs, and thus a candidate driver of angiogenesis in chondrosarcoma. The aim of this study was to determine whether the IFP is a productive source of EVs, and whether IFP-derived EVs induce angiogenesis in articular chondrocytes. The IFP released significantly more EVs than subcutaneous fat (n = 8 per depot; p = 0.027). Treating primary human articular chondrocytes with IFP EVs for 24 h upregulated VEGFA (+1.6-fold, p = 0.036) and downregulated BMP4 (-2.4-fold, p = 0.011), engaging the VEGF/eNOS/ERK axis that drives chondrosarcoma angiogenesis. Re-analysis of a previously published phospho-kinase dataset from the same donor EVs, corroborated by a pooled donor-group analysis (n = 3), supported activation of eNOS, ERK1/2, PLC-{gamma}1 and HSP27. These findings identify the IFP as a dominant source of EVs within the articular joint, which can induce a pro-angiogenic, VEGF-axis switch in articular cartilage cells, supporting a signalling model relevant to chondrosarcoma angiogenesis.

cancer biology↗

bioRxiv2026

GLP-1 and GIP receptor agonism does not directly drive skeletal muscle atrophy or impair myogenesis in primary human myotubes

GLP-1 and GIP/GLP-1 receptor agonists produce substantial weight loss in clinical trials but significant loss of lean body mass is reported. Whether this reflects a direct pharmacological effect on skeletal muscle or an indirect consequence of caloric restriction and reduced mechanical loading is unknown. Primary myoblasts were isolated from skeletal muscle of older adults with obesity undergoing orthopaedic surgery. GIPR and GLP-1R expression was characterised by RT- qPCR and flow cytometry. Differentiated myotubes were treated with semaglutide or GIP peptide and assessed for atrophy-related gene expression (qPCR), secretome perturbation (Olink Reveal), mitochondrial and glycolytic bioenergetics (Seahorse XF Real-Time ATP Rate Assay, glucose uptake, lactate secretion) and myotube morphology and myogenesis (immunofluorescence). GIPR mRNA was consistently detected across all donors; GLP-1R mRNA was undetectable by PCR, though LUXendin645 flow cytometry identified low-level surface GLP-1R protein in 51-66% of myoblasts. Neither semaglutide nor GIP altered atrophy-related gene expression or the secretome, with no proteins reaching significance. Semaglutide reduced glycolytic and total ATP production rates, accompanied by reduced lactate secretion, suggesting modest suppression of glycolytic flux; mitochondrial parameters were unaffected. Neither treatment impaired myotube thickness or differentiation; GIP increased myotube thickness after 8 days. Direct GLP-1 and GIP receptor activation does not substantively perturb atrophic signalling, myogenesis, or the secretome of primary human skeletal muscle myotubes. These findings suggest that lean mass loss with incretin-based therapies is unlikely to be driven by direct pharmacological action on skeletal muscle - particularly relevant as these agents are increasingly used in older adults at risk of sarcopenia.

physiology↗

bioRxiv2026

MicroAge Mission: Effects of Microgravity and Heat Shock Protein 10 Overexpression on the Proteome of Human Tissue-Engineered Muscle Constructs - Implications for Skeletal Muscle Ageing

Age-related loss of skeletal muscle mass and function, or sarcopenia, presents a growing clinical challenge, mirroring the accelerated muscle atrophy seen in microgravity. This study, part of the UK Space Agencys MicroAge Mission, aimed to investigate microgravity-induced proteomic changes in 3D human skeletal muscle constructs and assess whether mitochondrial Heat Shock Protein 10 (HSP10) overexpression could modulate these responses. Constructs derived from control human AB1167 myoblasts and AB1167 myoblasts that were transduced to overexpress HSP10, were flown to the International Space Station (ISS), with a ground reference experiment (GRE) conducted post-flight. Proteomic analysis using mass spectrometry and bioinformatics revealed significant alterations in metabolic, structural, and mitochondrial protein profiles after microgravity exposure. Microgravity caused downregulation of key proteins involved in energy metabolism, stress responses and structural integrity, while upregulating catabolic and apoptotic enzymes. Many of these modifications parallel previously reported changes in protein composition of muscle with ageing on earth. Overexpression of HSP10 attenuated the effects of microgravity, with fewer proteins showing significant changes and reduced disruption to mitochondrial and cytoskeletal components. Pathway analysis indicated that HSP10 overexpression preserved mitochondrial protein expression, particularly in the matrix, and promoted mitochondrial gene expression and translation under microgravity conditions. Notably, 284 proteins altered by microgravity in unmodified muscle constructs remained stable in HSP10-overexpressing constructs, suggesting a protective effect. MitoCarta 3.0 analysis confirmed that HSP10 expression modulated protein responses at the mitochondrial level, mitigating declines in bioenergetic proteins that are typically associated with microgravity. Collectively, the findings demonstrate that microgravity induces extensive proteomic remodelling in human muscle, which is partially offset by HSP10 overexpression. These results offer insights into muscle atrophy in spaceflight and suggest that targeting mitochondrial stress pathways via chaperone modulation may be a viable strategy to combat sarcopenia and disuse-induced muscle loss on Earth and in space.

physiology↗

bioRxiv2025

Systemic drivers and molecular mechanisms of sarcopenia in aetiology-specific end-stage liver disease

IntroductionPatients with end-stage liver disease (ESLD) often present with sarcopenia, defined as loss of skeletal muscle mass and quality, which is associated with reduced quality of life and increased mortality. However, the molecular mechanisms driving sarcopenia in ESLD are not fully understood and there are currently no therapeutic interventions. This study aimed to identify potential circulating factors contributing to sarcopenia progression in ESLD by assessing their role in driving transcriptomic alterations in skeletal muscle. MethodsQuadriceps muscle tissue, plasma and serum were obtained from ESLD patients (n=24) and age/sex-matched healthy controls (HC; n=18) (clinical trial ID: NCT04734496, ethical approval 18/WM/0167). Total RNA from snap-frozen vastus lateralis muscle biopsies underwent RNA sequencing (Illumina). Serum concentrations of 60 cytokines were profiled by Luminex and ELISA, with comparisons made both between ESLD and HC, and across ESLD aetiologies (alcohol-related, NAFLD, viral hepatitis, other). In vitro, primary human myotubes (from non-ESLD aged donors, NRES #16/SS/0172) were treated with 10% ESLD or HC plasma (24 h, n=6 per group) followed by RNA sequencing (BGI Genomics). Differentially expressed genes (p<0.05, fold-change >1.5) were identified via Qlucore and DESeq2, and pathway analysis performed using Ingenuity (Qiagen). The impact of physiological concentrations of candidate cytokines (IL-1, GDF-15, HGF) on myotube thickness, differentiation and mitochondrial function was assessed by immunofluorescence microscopy, RT-qPCR and metabolic flux assays. ResultsIn ESLD muscle, 387 and 225 genes were significantly up- and downregulated compared to HC respectively, with cellular senescence identified as a top dysregulated function. Upstream regulator analysis predicted activation of hepatocyte growth factor (HGF) and interleukin-1 signalling. Subgroup analysis revealed distinct transcriptomic profiles based on disease aetiology. Serum profiling identified 15 cytokines significantly elevated (p<0.05) and 5 reduced (p<0.05) in ESLD, including increased HGF and reduced interleukin-1 receptor antagonist. Stratified analysis also revealed aetiology specific cytokine profiles, with only GDF-15 significantly (P<0.0001) elevated in all groups. 24h ESLD plasma treatment induced 423 differentially expressed genes in human myotubes, which were again associated with significant activation of senescence pathways, with IL-1 identified as a key upstream driver. In vitro, IL-1, GDF-15, and HGF significantly reduced myotube thickness, nuclear fusion index and perturbed metabolism (Increased glycolysis, impaired oxidative phosphorylation). ConclusionsCollectively, these findings suggest that sarcopenia in ESLD is driven by aetiology-specific mechanisms, highlighting the potential for targeted therapies to improve muscle mass and function.

molecular biology↗

bioRxiv2025

MicroAge Mission: Experimental Design, Hardware Development and Operational Considerations for a Bespoke Culture System to Support Tissue-Engineered Skeletal Muscle Constructs.

Microgravity provides a unique model for understanding accelerated skeletal muscle loss, and potentially a model of muscle ageing, offering insights into the molecular mechanisms underlying reductions in muscle mass and function. During spaceflight, astronauts experience pronounced skeletal muscle atrophy. These effects appear similar to age-related muscle decline on Earth but on a significantly shorter timescale. Despite the incorporation of daily aerobic and resistance exercise on the International Space Station (ISS), countermeasures remain suboptimal, reflecting analogous challenges in exercise efficacy observed in ageing populations. The MicroAge Mission aimed to exploit microgravity conditions aboard the ISS to determine whether the molecular mechanisms underpinning reduced adaptive responses to contractile activity during ageing are analogous to those induced by spaceflight. The mission also explored proof-of-concept genetic interventions, including overexpression of Heat Shock Protein 10 (HSP10), a mitochondrial chaperone, to mitigate muscle atrophy and functional loss. To conduct these investigations, a tissue-engineering approach was employed to fabricate human skeletal muscle constructs, which were secured to custom-designed 3D-printed scaffolds. The scaffolds featured integrated microfluidic channels designed to interface with the fluid handling system within the flight hardware. The hardware, developed by Kayser Space Ltd, was specifically designed to interface with the European Space Agencys (ESA) Kubik incubator located within the Columbus module of the ISS. This research addresses critical methodological constraints in low Earth orbit (LEO) experimentation, providing a detailed account of pre-flight protocol development, muscle construct biofabrication techniques, and operational considerations. The findings establish a translational framework for future investigations into musculoskeletal degeneration, with implications for therapeutic strategies targeting both terrestrial ageing and astronaut musculoskeletal health.

bioengineering↗

bioRxiv2024

Peroxiredoxin 2 mediates redox-stimulated adaptations to oxidative phosphorylation induced by contractile activity in human skeletal muscle myotubes

Skeletal muscle generates superoxide during contractions, which is converted to hydrogen peroxide (H2O2). H2O2 has been proposed to activate signalling pathways and transcription factors that regulate adaptive responses to exercise, but the concentration required to oxidize and activate key redox-sensitive signalling proteins in vitro is much higher than the typical intracellular levels seen in muscle after exercise. We hypothesized that 2-Cys-peroxiredoxins (PRDX), which rapidly oxidize in the presence of physiological concentrations of H2O2, serve as intermediary signalling molecules and play a crucial role in activating adaptive pathways following muscle contractions. This study has examined the human muscle myotube responses to contractile activity, or exposure to low extracellular concentrations (2.5-5 {micro}M) of H2O2 and whether knock down of muscle PRDX2 alters the differential gene expression (DEG) that results from these stresses. Exposure of human skeletal muscle myotubes to a 15 min period of aerobic electrically stimulated isometric contractions or 5M H2O2 induced substantial changes in DEG with modification of many genes associated with adaptations of skeletal muscle to contractile activity. Common DEG in these conditions included upregulation of genes associated with increased mitochondrial oxidative phosphorylation, including COX1, COX2, COX3 and ATP6. In myotubes with PRDX2 knock down (94% decrease in PRDX2 mRNA), the upregulation of genes associated with increased mitochondrial oxidative phosphorylation was abolished following contractile activity or exposure to H2O2. These data indicate that a common effect of contractile activity and exposure to "physiological" levels of H2O2 in human myotubes is to increase the expression of multiple genes associated with increased mitochondrial oxidative phosphorylation. Furthermore, these effects were abolished in PRDX2 knock down myotubes indicating that adaptations to upregulate multiple genes related to increased mitochondrial capacity in human muscle myotubes in response to exercise is both redox regulated and requires PRDX2 as an essential mediator of the effects of H2O2.

physiology↗

bioRxiv2024

Activation of the proton-sensing GPCR, GPR65 on fibroblast-like synoviocytes contributes to inflammatory joint pain.

Inflammation is associated with localised acidosis, however, attributing physiological and pathological roles to proton-sensitive receptors is challenging due to their diversity and widespread expression. Here, agonists of the proton-sensing GPCR, GPR65, were systematically characterised. The synthetic agonist BTB09089 (BTB) recapitulated many proton-induced signalling events and demonstrated selectivity for GPR65. BTB was used to show that GPR65 activation on fibroblast-like synoviocytes (FLS), cells that line synovial joints, results in the secretion of pro-inflammatory mediators capable of recruiting immune cells and sensitising sensory neurons. Intra-articular injection of BTB resulted in GPR65-dependent sensitisation of knee-innervating neurons and nocifensive behaviours in mice. Stimulation of GPR65 on human FLS also triggered the release of inflammatory mediators and synovial fluid samples from human osteoarthritis patients were shown to activate GPR65. These results suggest a role of GPR65 in mediating cell-cell interactions that drive inflammatory joint pain in both mice and humans.

neuroscience↗

bioRxiv2020

Protein-carbohydrate ingestion alters Vps34 cellular localization independent of changes in kinase activity in human skeletal muscle

The mechanistic target of rapamycin (mTOR) complex 1 (mTORC1) regulates cell size and growth in response to nutrients, however, the mechanisms by which nutrient levels are sensed by mTORC1 in human skeletal muscle are yet to be fully elucidated. The Class III PI3Kinase Vps34 has recently been proposed as a sensor essential for mTORC1 activation following nutrient stimulation. We therefore investigated the effects of increasing nutrient availability through protein-carbohydrate (PRO-CHO) feeding on Vps34 kinase activity and cellular localization in human skeletal muscle. Eight young, healthy males (age - 21 {+/-} 0.5yrs, mean {+/-} SEM) ingested a PRO-CHO beverage containing 20/44/1g PRO/CHO/FAT respectively, with skeletal muscle biopsies obtained at baseline and 1h and 3h post-feeding. PRO-CHO feeding did not alter Vps34 kinase activity, but did stimulate Vps34 translocation toward the cell periphery (PRE (mean{+/-}SEM) - 0.273{+/-}0.021, 1h - 0.347{+/-}0.022, Pearsons Coefficient (r)) where it co-localized with mTOR (PRE - 0.312{+/-}0.018, 1h - 0.348{+/-}0.024, Pearsons Coefficient (r))). These alterations occurred in parallel to an increase in S6K1 kinase activity - 941{+/-}164% of PRE at 1h post-feeding). Subsequent in vitro experiments in C2C12 and human primary myotubes displayed no effect of the Vps34-specific inhibitor SAR405 on mTORC1 signalling responses to elevated nutrient availability. Therefore, in summary, PRO-CHO ingestion does not increase Vps34 activity in human skeletal muscle, whilst pharmacological inhibition of Vps34 does not prevent nutrient stimulation of mTORC1 in vitro. However, PRO-CHO ingestion promotes Vps34 translocation to the cell periphery, enabling Vps34 to associate with mTOR. Therefore, our data suggests that interaction between Vps34 and mTOR, rather than changes in Vps34 activity per se may be involved in PRO-CHO activation of mTORC1 in human skeletal muscle.

physiology↗