Muscle Cell Growth Research Articles

Urolithin B suppresses phenotypic switch in vascular smooth muscle cells induced by PDGF-BB via inhibiting the PI3K-AKT pathway.

Atherosclerosis (AS) is a prevalent cardiovascular condition, and the growth and phenotypic switch of vascular smooth muscle cells (VSMCs) play a crucial role in its development. Studies have revealed that the activation of certain transcription factors and signaling pathways can trigger these cellular changes. Consequently, targeting these pathways and pivotal molecules has emerged as a promising strategy for AS treatment. Drugs that can reverse the cellular changes in VSMCs may offer new therapeutic options for AS, marking a significant advancement. While previous research has suggested that urolithin B (Uro B) possesses anti-atherosclerotic properties, its exact mechanism remains to be fully understood, especially the effect of Uro B in VSMCs. This study discovered that Uro B can impede the proliferation and migration of VSMCs prompted by PDGF-BB, as well as their phenotypic changes, indicating that Uro B could potentially prevent AS by inhibiting the phenotypic switch of VSMCs.

Directed Cell Growth of C2C12 Cells on ECM Free Bioprinted Nano/Micro Scaffolds.

Skeletal muscle cell growth impairment can result in severe health issues, such as reduced mobility, metabolic problems, and cardiovascular issues, which can significantly impact an individual's overall health and lifestyle. To address this issue, it is essential to adopt a multi-faceted approach. Conventional 2D cell culture methods fail to replicate the critical features of in vivo micro/nanoarchitecture, which is crucial for the growth of skeletal muscle cells. In this study, the directed growth of mouse skeletal myoblasts (C2C12) cells on ECM-free biocompatible scaffolds is demonstrated and fabricated using two-photon lithography (TPL). These scaffolds are 2D and 3D and have nano/micro-features derived from chitosan-based carbon quantum dots (Ch-CQDs). Ch-CQDs act as two-photon initiators for TPL and also provide the scaffolds with adequate mechanical strength and specific binding sites. These scaffolds are biocompatible and can support cellular adhesion and growth without the need for ECM coating. The nano/micro scaffolds mimic the in vivo cellular microenvironment, enabling directed cell growth on ECM-free surfaces. The fabricated scaffolds have tunable mechanical strength ranging from 0.09 to 0.75GPa. By using Ch-CQDs, scaffolds are created that promote cell growth and alignment, which is crucial for skeletal muscle cell growth.

Dysfunction of perivascular adipose tissue in metabolic syndrome and obesity: the role of the gasotransmitter hydrogen sulfide (review)

The development of novel strategies for diagnosing, treating, and preventing cardiovascular diseases (CVDs) linked to metabolic syndrome and obesity presents a significant challenge for the scientific community. There is a pressing need to identify effective compounds that target the underlying pathogenic mechanisms of these disorders. Increasing knowledge about the pathogenesis of CVDs has highlighted the crucial role of perivascular adipose tissue (PVAT) in maintaining cardiovascular homeostasis. PVAT is a metabolically active endocrine organ that plays a key role in regulating blood vessel tone, endothelial function, and the growth and proliferation of vascular smooth muscle cells. However, in metabolic disorders, there is a disruption in the functional activity of PVAT cellular components and an imbalance in the production of vasoactive substances, leading to the development and progression of CVDs. This review systematically examines the morphofunctional changes in PVAT associated with metabolic syndrome and obesity, emphasizes the dysfunction of PVAT as a key pathogenetic factor in cardiovascular disease, and evaluates the potential of hydrogen sulfide (H2S) produced by PVAT as a promising vasoregulatory agent based on existing data.

Lnc-MEG8 regulates yak myoblast differentiation via the miR-22-3p/RTL1 axis

BackgroundThe yak (Bos grunniens) is essential to the livelihoods of Tibetan people on the Qinghai-Tibet Plateau; however, its growth and productivity are constrained by the region's harsh climate and high altitude. Yak skeletal muscle myoblasts, which have evolved to thrive under these challenging conditions, offer a valuable model for investigating muscle development. In this study, we performed transcriptome profiling of yak longissimus dorsi muscle at different growth stages, identifying a key long non-coding RNA, LncRNA-XR_314844 (Lnc-MEG8), with a potential role in muscle development.ResultsWe developed a novel technique to isolate high-quality yak myoblasts, enabling detailed analysis of Lnc-MEG8. Our results indicated that Lnc-MEG8's subcellular localization varies during muscle cell growth: it is found in both the nucleus and cytoplasm during proliferation but shifts mainly to the cytoplasm during differentiation. Functional experiments showed that Lnc-MEG8 promotes cell proliferation and inhibits differentiation, while its silencing had the opposite effect. Further analysis revealed that both Lnc-MEG8 and the gene RTL1 share miR-22-3p as a common target. Dual-luciferase assays confirmed miR-22-3p directly targets both Lnc-MEG8 and RTL1 mRNA. Co-transfection of Lnc-MEG8 and a miR-22-3p mimic restored RTL1 expression, highlighting Lnc-MEG8's regulatory role. Lnc-MEG8 also counteracts miR-22-3p's suppression of key muscle genes such as MyF5 and MyoG, facilitating myotube formation.ConclusionThese findings demonstrate that the Lnc-MEG8-miR-22-3p-RTL1 axis plays a crucial role in yak muscle development, providing insights that could advance muscle tissue engineering and enhance yak meat quality.

Bridging the Gap: Supplements Strategies from Experimental Research to Clinical Applications in Sarcopenic Obesity.

Obesity causes fat accumulation, and sarcopenia causes loss of muscle mass and strength; together, they worsen insulin resistance and accelerate muscle decline, creating a harmful cycle. Some supplements, along with physical exercise, could be remedies for sarcopenic obesity (SO). In this review, we aim to draw a comparison between supplements studied in experimental research and those evaluated in clinical studies for SO. In experimental studies, Sea Buckthorn-in forms such as oil, freeze-dried powder or pomace-has been shown to enhance muscle cell growth, improve gut microbiota, provide hypoglycemic benefits and increase muscle mass by promoting protein synthesis. Increased consumption of Omega-3 fatty acids may play a protective role against SO in women. Melatonin may positively impact obesity and SO by reducing oxidative stress. Elevated irisin levels, such as those observed with vitamin D supplementation, could prevent muscle wasting and fat gain in SO by improving insulin sensitivity and reducing inflammation. There have been many studies highlighting the potential of vitamin D in preventing age related sarcopenia; however, the effect of vitamin D supplementation in SO is under-researched and appears less promising. Future clinical trials using natural supplements hold promise, as these provide multiple beneficial components that may work synergistically to treat SO.

A Comparison between Severity-dependent Protocol and Fixed Dose Regimen of Oral Vitamin D Supplementation on Correction of Hypovitaminosis D among Dialysis Patients

Low vitamin D status is associated with either low muscle mass or impaired muscle function in dialysis patients. However, there is no consensus on how best to correct hypovitaminosis D, defined as serum 25-hydroxyvitamin D level <30ng/mL, in patients with end-stage kidney disease (ESKD). This study investigated the effect of different vitamin D supplementation regimens on sarcopenia outcomes in dialysis patients. This was a prospective randomized controlled trial. ESKD patients treated with maintenance hemodialysis (HD) or peritoneal dialysis with low vitamin D status on a ratio of 1:1, were randomized to either receive oral ergocalciferol utilizing a severity-dependent treatment protocol for low vitamin D status suggested by the Kidney Disease Outcomes Quality Initiative as a control group or a fixed-dose regimen of 20,000international units/week. The changes in muscle mass were measured by bioimpedance spectroscopy, muscle strength was assessed by a hand grip dynamometer, physical performance was determined by gait speed, and muscle-related biomarkers were examined. A total of 76 dialysis patients were randomized (HD=43.4%). Baseline characteristics, including age, dialysis vintage, and muscle parameters were similar. After supplementation, the average serum 25-hydroxyvitamin D levels in the severity-dependent and fixed-dose groups were significantly elevated from 14.5±7.3 to 27.2±13.2ng/mL, P<.001 and from 15.1±6.4 to 28.8±11.5ng/mL, P<.001, respectively, and did not differ between groups at 6months (P=.60). Despite comparable energy and protein intake, the mean bioimpedance spectroscopy-derived total body muscle mass normalized to height squared was significantly increased at 6months in the fixed-dose group (14.5±3.3 to 15.3±3.0kg/m2, P=.03) compared with the severity-dependent protocol (13.5±2.7 to 13.7±2.9kg/m2, P=.58). In the subgroup analysis, muscle mass improvement was statistically elevated in peritoneal dialysis patients (P=.01) while unaltered among HD patients (P=.88) in the fixed-dose group. Muscle strength, gait speed, and serum insulin-like growth factor-1 level, as the mediators of muscle cell growth, were not different between the two groups at 6months (P>.05). Neither hypercalcemia nor hyperphosphatemia was found throughout the study. A fixed-dose ergocalciferol supplementation demonstrates similar performance in the correction of low vitamin D status but better muscle mass improvement than a severity-dependent protocol among ESKD patients. Regular dosing intervals of weekly vitamin D supplementation appear to be a promising treatment for sarcopenia among patients undergoing dialysis.

Photo/thermo-sensitive chitosan and gelatin-based interpenetrating polymer network for mimicking muscle tissue extracellular matrix

The dynamic interplay between extracellular matrix (ECM), its 3D architecture and resident cells plays a pivotal role in cell behavior influencing essential processes like proliferation, migration, and differentiation. Matrix-based 3D culture systems have emerged as valuable tools to model organ and tissue interactions in vitro. A 3D matrix analog must possess high biocompatibility and fully reproduce the characteristics of the native tissue in terms of mechanical properties. In this regard, interpenetrating polymer networks (IPNs) are particularly attractive because of the high tunability of their physicochemical properties. In this study, a chitosan (Ch) and modified gelatin (GelMA) IPN with a sol-gel transition triggered by two external physical stimuli, UV light and temperature, was designed to mimic the muscle tissue ECM in terms of mechanical stiffness. The system was deeply characterized demonstrating to support not only the growth and viability of muscle cells embedded within the hydrogel, but also cell differentiation toward muscle phenotype.

Effects of rumen metabolite butyric acid on bovine skeletal muscle satellite cells proliferation, apoptosis and transcriptional states during myogenic differentiation

Butyric acid, a pivotal short-chain fatty acid in rumen digestion, profoundly influences animal digestive and locomotor systems. Extensive research indicates its direct or indirect involvement in the growth and development of muscle and fat cells. However, the impact of butyric acid on the proliferation and differentiation of bovine skeletal muscle satellite cells (SMSCs) remains unclear. This study aimed to elucidate the effects of butyrate on SMSCs proliferation and differentiation. After isolating, SMSCs were subjected to varying concentrations of sodium butyrate (NaB) during the proliferation and differentiation stages. Optimal treatment conditions (1 mM NaB for 2 days) were determined based on proliferative force, cell viability, and mRNA expression of proliferation and differentiation marker genes. Transcriptome sequencing was employed to screen for differential gene expression between 1 mM NaB-treated and untreated groups during SMSCs differentiation. Results indicated that lower NaB concentrations (≤1.0 mM) inhibited proliferation while promoting differentiation and apoptosis after a 2-day treatment. Conversely, higher NaB concentrations (≥2.0 mM) suppressed proliferation and differentiation and induced apoptosis. Transcriptome sequencing revealed differential expression of genes(ND1, ND3, CYTB, COX2, ATP6, MYOZ2, MYOZ3, MYBPC1 and ATP6V0A4,etc.) were associated with SMSCs differentiation and energy metabolism, enriching pathways such as Oxidative phosphorylation, MAPK, and Wnt signaling. These findings offer valuable insights into the molecular mechanisms underlying butyrate regulation of bovine SMSCs proliferation and differentiation, as well as muscle fiber type conversion in the future study.

Pde3a and Pde3b regulation of murine pulmonary artery smooth muscle cell growth and metabolism.

A role for metabolically active adipose tissue in pulmonary hypertension (PH) pathogenesis is emerging. Alterations in cellular metabolism in metabolic syndrome are triggers of PH-related vascular dysfunction. Metabolic reprogramming in proliferative pulmonary vascular cells causes a metabolic switch from oxidative phosphorylation to glycolysis. PDE3A and PDE3B subtypes in the regulation of metabolism in pulmonary artery smooth muscle cells (PASMC) are poorly understood. We previously found that PDE3A modulates the cellular energy sensor, AMPK, in human PASMC. We demonstrate that global Pde3a knockout mice have right ventricular (RV) hypertrophy, elevated RV systolic pressures, and metabolic dysfunction with elevated serum free fatty acids (FFA). Therefore, we sought to delineate Pde3a/Pde3b regulation of metabolic pathways in PASMC. We found that PASMC Pde3a deficiency, and to a lesser extent Pde3b deficiency, downregulates AMPK, CREB and PPARγ, and upregulates pyruvate kinase dehydrogenase expression, suggesting decreased oxidative phosphorylation. Interestingly, siRNA Pde3a knockdown in adipocytes led to elevated FFA secretion. Furthermore, PASMC exposed to siPDE3A-transfected adipocyte media led to decreased α-SMA, AMPK and CREB phosphorylation, and greater viable cell numbers compared to controls under the same conditions. These data demonstrate that deficiencies of Pde3a and Pde3b alter pathways that affect cell growth and metabolism in PASMC.

(189) MORPHOLOGICAL ANALYSIS OF TRANSGENDER PENIS

Abstract Introduction Erectile dysfunction (ED) is a serious medical condition that impacts quality of life. An underlying cause is loss of cavernous nerve (CN) innervation, which initiates remodeling of the corpora cavernosa of the penis including smooth muscle apoptosis and increased collagen. There are few studies of penile remodeling in patient tissue because of low availability of patient corpora cavernosa specimens, and in acquiring appropriate controls, however it is critical to ensure that our animal models adequately parallel patient conditions. Objective In this study a detailed analysis of penile morphology was performed on corpora cavernosa tissue from transgender patients in comparison to Peyronie’s controls, in order to determine if corpora cavernosa from transgender patients may be useful as a control for morphological studies of the human penis. Methods Transgender penis tissue (n = 18) was obtained from patients undergoing penectomy surgery for gender reassignment. Corpora cavernosa tissue was obtained from Peyronie’s (control, n = 8) patients that were undergoing prosthesis implantation. Immunohistochemical analysis for alpha-ACTIN, CD31, P4HB, and nNOS were performed to characterize the transgender tissue in comparison to Peyronie’s controls. Trichrome stain, hydroxyproline assay, and western analysis for alpha-actin (smooth muscle) and GAPDH, were performed to examine smooth muscle retention and collagen abundance. Primary cell cultures were established from transgender and Peyronie’s corpora cavernosa, and growth in response to SHH, BMP4 and GREM1 treatment were quantified. The effect of 17 □-estradiol on smooth muscle cultures were examined. Results Normal smooth muscle, endothelium, fibroblasts, neural tissue, collagen, and SHH signaling in corpora cavernosa from transgender patients was found in comparison to Peyronie’s controls. 17 beta-estradiol treatment did not alter smooth muscle cell growth or the response to SHH pathway signaling. Conclusions Transgender patients typically undergo 17 beta-estradiol treatment prior to penectomy. While there have been studies which document the effects of estrogen on penile embryogenesis and hypospadias, little is known about the effect estrogen may have on adult corpora cavernosa tissue. In this study a detailed analysis of penile morphology was performed in transgender patients in comparison to Peyronie’s controls, in order to determine if the transgender tissue may be useful as a control for patient studies of corpora cavernosa morphology. No apparent difference in penile morphology was observed between Peyronie’s and transgender patients. While further study is needed, transgender corpora cavernosa tissue may be useful as a control for studies of patient penile morphology. Disclosure No.

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.

In vivo biocompatibility of a new hydrophobic coated Al/Al2O3 nanowire surface on stents

BackgroundIntima proliferation and in-stent restenosis is a challenging situation in interventional treatment of small vessel obstruction. Al/Al2O3 nanowires have been shown to accelerate vascular endothelial cell proliferation and migration in vitro, while suppressing vascular smooth muscle cell growth. Moreover, surface modification of Al/Al2O3 nanowires with poly[bis(2,2,2-trifluoromethoxy)phosphazene (PTFEP) coating enables further advantages such as reduced platelet adhesion. Therefore, the study's goal was to compare the biocompatibility of novel Al/Al2O3 + PTFEP coated nanowire bare-metal stents to uncoated control stents in vivo using optical coherence tomography (OCT), quantitative angiography and histomorphometric assessment. Methods15 Al/Al2O3 + PTFEP coated and 19 control stents were implanted in the cervical arteries of 9 Aachen minipigs. After 90 days, in-stent stenosis, thrombogenicity, and inflammatory response were assessed. Scanning electron microscopy was used to analyse the stent surface. ResultsOCT analysis revealed that neointimal proliferation in Al/Al2O3 + PTFEP coated stents was significantly reduced compared to control stents. The neointimal area was 1.16 ± 0.77 mm2 in Al/Al2O3 + PTFEP coated stents vs. 1.98 ± 1.04 mm2 in control stents (p = 0.004), and the neointimal thickness was 0.28 ± 0.20 vs. 0.47 ± 0.10 (p = 0.003). Quantitative angiography showed a tendency to less neointimal growth in coated stents. Histomorphometry showed no significant difference between the two groups and revealed an apparent inflammatory reaction surrounding the stent struts. ConclusionsAt long-term follow-up, Al/Al2O3 + PTFEP coated stents placed in peripheral arteries demonstrated good tolerance with no treatment-associated vascular obstruction and reduced in-stent restenosis in OCT. These preliminary in vivo findings indicate that Al/Al2O3 + PTFEP coated nanowire stents may have translational potential to be used for the prevention of in-stent restenosis.

Extrusion-Based 3D Bioprinting of Bioactive and Piezoelectric Scaffolds as Potential Therapy for Treating Critical Soft Tissue Wounds.

Objective: This study focuses on developing bioactive piezoelectric scaffolds that could deliver bioelectrical cues to potentially treat injuries to soft tissues such as skeletal muscles and promote active regeneration. Approach: To address the underexplored aspect of bioelectrical cues in skeletal muscle tissue engineering (SMTE), we developed piezoelectric bioink based on natural bioactive materials such as sodium alginate, gelatin, and chitosan. Extrusion-based 3D bioprinting was utilized to develop scaffolds that mimic muscle stiffness and generate electrical stimulation (E-stim) when subjected to forces. The biocompatibility of these scaffolds was tested with the C2C12 muscle cell line. Results: The bioink demonstrated suitable rheological properties for 3D bioprinting, resulting in high-resolution composite sodium alginate-gelatin-chitosan scaffolds with good structural fidelity. The scaffolds exhibited a 42-60 kPa stiffness, similar to muscle. When a controlled force of 5N was applied to the scaffolds at a constant frequency of 4 Hz, they generated electrical fields and impulses (charge), indicating their suitability as a stand-alone scaffold to generate E-stim and instill bioelectrical cues in the wound region. The cell viability and proliferation test results confirm the scaffold's biocompatibility with C2C12s and the benefit of piezoelectricity in promoting muscle cell growth kinetics. Our study indicates that our piezoelectric bioink and scaffolds offer promise as autonomous E-stim-generating regenerative therapy for SMTE. Innovation: A novel approach for treating skeletal muscle wounds was introduced by developing a bioactive electroactive scaffold capable of autonomously generating E-stim without stimulators and electrodes. This scaffold offers a unique approach to enhancing skeletal muscle regeneration through bioelectric cues, addressing a major gap in the SMTE, that is, fibrotic tissue formation due to delayed muscle regeneration. Conclusion: A piezoelectric scaffold was developed, providing a promising solution for promoting skeletal muscle regeneration. This development can potentially address skeletal muscle injuries and offers a unique approach to facilitating skeletal muscle wound healing.

Mature adipocytes inhibit differentiation of myogenic cells but stimulate proliferation of fibro-adipogenic precursors derived from trout muscle in vitro

Interactions between tissues and cell types, mediated by cytokines or direct cell–cell exchanges, regulate growth. To determine whether mature adipocytes influence the in vitro growth of trout mononucleated muscle cells, we developed an indirect coculture system, and showed that adipocytes (5 × 106 cells/well) derived from perivisceral adipose tissue increased the proliferation (BrdU-positive cells) of the mononucleated muscle cells (26% vs. 39%; p < 0.001) while inhibiting myogenic differentiation (myosin+) (25% vs. 15%; p < 0.001). Similar effects were obtained with subcutaneous adipose tissue-derived adipocytes, although requiring more adipocytes (3 × 107 cells/well vs. 5 × 106 cells/well). Conditioned media recapitulated these effects, stimulating proliferation (31% vs. 39%; p < 0.001) and inhibiting myogenic differentiation (32 vs. 23%; p < 0.001). Adipocytes began to reduce differentiation after 24 h, whereas proliferation stimulation was observed after 48 h. While adipocytes did not change pax7+ and myoD1/2+ percentages, they reduced myogenin+ cells showing inhibition from early differentiation stage. Finally, adipocytes increased BrdU+ cells in the Pdgfrα+ population but not in the myoD+ one. Collectively, our results demonstrate that trout adipocytes promote fibro-adipocyte precursor proliferation while inhibiting myogenic cells differentiation in vitro, suggesting the key role of adipose tissue in regulating fish muscle growth.

Immunomodulatory imide drugs inhibit human detrusor smooth muscle contraction and growth of human detrusor smooth muscle cells, and exhibit vaso-regulatory functions

BackgroundThe immunomodulatory imide drugs (IMiDs) thalidomide, lenalidomide and pomalidomide may exhibit therapeutic efficacy in the prostate. In lower urinary tract symptoms (LUTS), voiding and storage disorders may arise from benign prostate hyperplasia, or overactive bladder. While current therapeutic options target smooth muscle contraction or cell proliferation, side effects are mostly cardiovascular. Therefore, we investigated effects of IMiDs on human detrusor and porcine artery smooth muscle contraction, and growth-related functions in detrusor smooth muscle cells (HBdSMC). MethodsCell viability was assessed by CCK8, and apoptosis and cell death by flow cytometry in cultured HBdSMC. Contractions of human detrusor tissues and porcine interlobar and coronary arteries were induced by contractile agonists, or electric field stimulation (EFS) in the presence or absence of an IMID using an organ bath. Proliferation was assessed by EdU assay and colony formation, cytoskeletal organization by phalloidin staining, ResultsDepending on tissue type, IMiDs inhibited cholinergic contractions with varying degree, up to 50 %, while non-cholinergic contractions were inhibited up to 80 % and 60 % for U46619 and endothelin-1, respectively, and EFS-induced contractions up to 75 %. IMiDs reduced viable HBdSM cells in a time-dependent manner. Correspondingly, proliferation was reduced, without showing pro-apoptotic effects. In parallel, IMiDs induced cytoskeletal disorganization. ConclusionsIMiDs exhibit regulatory functions in various smooth muscle-rich tissues, and of cell proliferation in the lower urinary tract. This points to a novel drug class effect for IMiDs, in which the molecular mechanisms of action of IMiDs merit further consideration for the application in LUTS.

Irisin promotes tilapia muscle cell growth and amino acid uptake via IGF-1 signaling.

Irisin is a recently discovered myokine that facilitates the browning of white adipose tissue, increases glucose uptake in skeletal muscle, and influences metabolic processes in the liver. However, its potential effects on amino acid absorption remained largely unexplored. This study aimed to elucidate the role of irisin in modulating amino acid uptake and delineate the underlying molecular mechanisms involved. To this end, juvenile tilapia were administered intraperitoneal irisin injections at 100 ng/g body weight over 8 weeks. Evaluation of various physiological parameters revealed that irisin supplementation significantly improved the specific growth rate and feed conversion efficiency while reducing feed consumption. Muscle tissue analysis revealed that irisin significantly modified the proximate composition by increasing protein content and reducing lipid levels. It also significantly raised the levels of both essential and non-essential amino acids in the muscle. Histological analysis demonstrated that irisin-stimulated muscle growth through hyperplasia rather than hypertrophy, corroborated by upregulated IGF-1 mRNA and downregulated myostatin mRNA expression. Mechanistic studies in cultured tilapia muscle cells elucidated that irisin activated integrin receptors on muscle cells, which subsequently engaged IGF-1/IGF-1R signaling. Downstream of IGF-1R activation, irisin simultaneously stimulates the ERK1/2 and PI3K/mTORC2/Akt pathways. The convergence of these pathways upregulates L-type amino acid transporter 1 expression, thereby augmenting amino acid uptake into muscle cells. In summary, irisin supplementation in tilapia leads to improved muscle growth, predominantly via hyperplasia and augmented amino acid assimilation, governed by intricate cellular signaling pathways. These findings provide valuable aquaculture applications and novel insights into muscle development.

The effect of gut microbiota-derived carnosine on mucosal integrity and immunity in broiler chickens challenged with Eimeria maxima

In the first study, an in vitro culture system was developed to investigate the effects of carnosine on macrophage proinflammatory cytokine response using an established chicken macrophage cell line (CMC), gut integrity using a chicken intestinal epithelial cell line (IEC), muscle differentiation in quail muscle cells (QMCs) and primary chicken embryonic muscle cells (PMCs), and direct anti-parasitic effect against Eimeria maxima sporozoites. Cells to be tested were seeded in 24-well plates and treated with carnosine at 4 different concentrations (0.1, 1.0, and 10.0 µg). After 18 h of incubation, cells were harvested to measure gene expression of proinflammatory cytokines in CMC, tight junction (TJ) proteins in IECs, and muscle cell growth markers in QMCs and PMCs. In vivo trials were conducted to investigate the effect of dietary carnosine on disease parameters in broiler chickens challenged with E. maxima. One hundred and twenty male broiler chickens (0-day-old) were allocated into four treatment groups: (1) basal diet without infection (NC), (2) basal diet with E. maxima infection (PC), (3) carnosine at 10.0 mg/kg feed with PC (HCS), and (4) carnosine at 1.0 mg/kg feed with PC (LCS). All groups except NC were orally infected with E. maxima on day 14. Jejunal samples were collected for lesion scoring and jejunum gut tissues were used for transcriptomic analysis of cytokines and TJ proteins. In vitro, carnosine treatment significantly decreased IL-1β gene expression in CMC following LPS stimulation. In vivo feeding studies showed that dietary carnosine increased BW and ADG of chickens in E. maxima-infected groups and reduced the jejunal lesion score and fecal oocyst shedding in HCS group. Jejunal IL-1β, IL-8, and IFN-γ expression were suppressed in the HCS group compared to PC. The expression levels of claudin-1 and occludin in IECs were also increased in HCS following carnosine treatment. In conclusion, these findings highlight the beneficial effects of dietary carnosine supplementation on intestinal immune responses and gut barrier function in broiler chickens exposed to E. maxima infection.

A novel protein encoded by circLARP1B promotes the proliferation and migration of vascular smooth muscle cells by suppressing cAMP signaling

Background and aimsCircular RNA (circRNA) is closely related to atherosclerosis (AS) incidence and progression, but its regulatory mechanism in AS needs further elucidation. AS development is significantly influenced by abnormal vascular smooth muscle cells (VSMCs) growth and migration. This study explored the potential protein role of circLARP1B in VSMC proliferation and migration. MethodsWe performed whole-transcriptome sequencing in human normal arterial intima and advanced atherosclerotic plaques to screen for differentially expressed circRNAs. The sequencing results were combined with database analysis to screen for circRNAs with coding ability. Real-time quantitative polymerase chain reaction was utilized to assess circLARP1B expression levels in atherosclerotic plaque tissues and cells. circLARP1B-243aa function and pathway in VSMCs growth and migration were studied by scratch, transwell, 5-ethynyl-2′-deoxyuridine, cell counting kit-8, and Western blot experiments. ResultsWe found that circLARP1B was downregulated in atherosclerotic plaque tissue and promoted the proliferation and migration of VSMCs. circLARP1B encodes a novel protein with a length of 243 amino acids. Through functional experiments, we confirmed the role of circLARP1B-243aa in enhancing VSMCs migration and proliferation. Mechanistically, circLARP1B-243aa promotes VSMCs migration and growth by upregulating phosphodiesterase 4C to inhibit the cyclic adenosine monophosphate signaling pathway. ConclusionsOur results suggested that circLARP1B could promote VSMCs growth and migration through the encoded protein circLARP1B-243aa. Therefore, it could be a treatment target and biomarker for AS.

Transcriptome analysis of mRNA and miRNA in the development of LeiZhou goat muscles

The progression of muscle development is a pivotal aspect of animal ontogenesis, where miRNA and mRNA exert substantial influence as prominent players. It is important to understand the molecular mechanisms involved in skeletal muscle development to enhance the quality and yield of meat produced by Leizhou goats. We employed RNA sequencing (RNA-SEQ) technology to generate miRNA-mRNA profiles in Leizhou goats, capturing their developmental progression at 0, 3, and 6 months of age. A total of 977 mRNAs and 174 miRNAs were found to be differentially expressed based on our analysis. Metabolic pathways, calcium signaling pathways, and amino acid synthesis and metabolism were found to be significantly enriched among the differentially expressed mRNA in the enrichment analysis. Meanwhile, we found that among these differentially expressed mRNA, some may be related to muscle development, such as MYL10, RYR3, and CSRP3. Additionally,, we identified five muscle-specific miRNAs (miR-127-3p, miR-133a-3p, miR-193b-3p, miR-365-3p, and miR-381) that consistently exhibited high expression levels across all three stages. These miRNAs work with their target genes (FHL3, SESN1, PACSIN3, LMCD1) to regulate muscle development. Taken together, our findings suggest that several miRNAs and mRNAs are involved in regulating muscle development and cell growth in goats. By uncovering the molecular mechanisms involved in muscle growth and development, these findings contribute valuable knowledge that can inform breeding strategies aimed at enhancing meat yield and quality in Leizhou goats.

Gelatin/heparin coated bio-inspired polyurethane composite fibers to construct small-caliber artificial blood vessel grafts

Long-term patency and ability for revascularization remain challenges for small-caliber blood vessel grafts to treat cardiovascular diseases clinically. Here, a gelatin/heparin coated bio-inspired polyurethane composite fibers-based artificial blood vessel with continuous release of NO and biopeptides to regulate vascular tissue repair and maintain long-term patency is fabricated. A biodegradable polyurethane elastomer that can catalyze S-nitrosothiols in the blood to release NO is synthesized (NPU). Then, the NPU core-shell structured nanofiber grafts with requisite mechanical properties and biopeptide release for inflammation manipulation are fabricated by electrospinning and lyophilization. Finally, the surface of tubular NPU nanofiber grafts is coated with heparin/gelatin and crosslinked with glutaraldehyde to obtain small-caliber artificial blood vessels (ABVs) with the ability of vascular revascularization. We demonstrate that artificial blood vessel grafts promote the growth of endothelial cells but inhibit the growth of smooth muscle cells by the continuous release of NO; vascular grafts can regulate inflammatory balance for vascular tissue remodel without excessive collagen deposition through the release of biological peptides. Vascular grafts prevent thrombus and vascular stenosis to obtain long-term patency. Hence, our work paves a new way to develop small-caliber artificial blood vessel grafts that can maintain long-term patency in vivo and remodel vascular tissue successfully.