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Over half million individuals suffer from chronic kidney disease (CKD) worldwide. In addition to raising the possibility of cardiovascular diseases, skeletal myopathy remains a challenging complication that is highly correlated with mortality and a lower quality of life. Granulocyte-colony stimulating factor (G-CSF) is an active cytokine for mobilization of immunological and hematopoietic stem cells that can replace exogenous stem cell infusions. So, it is seen as a less expensive and noninvasive tool for regenerative medicine. Sixty three rats were divided into 4 groups: I control, II CKD induced, IIIa, IIIb treated and IV recovery groups. After induction of CKD in all rats, group II were sacrificed after 4 weeks. Rats of group IIIa received NaHCO3. Group IIIb rats were injected subcutaneously by G-CSF as 100 µg/kg/day for 5 successive days in addition to NaHCO3 as group IIIa. Group IV rats were housed for 4 weeks without treatment. Serum urea, creatinine, tissue MDA& TNF-α were assessed. Renal and gastrocnemius muscle sections were evaluated for histological structure, CD34 and myogenin immune expression, morphometric and statistical analyses. The CKD group revealed a significant increase in MDA and TNF-α. Furthermore, features of renal injury, muscle degenerative changes, increased collagen and decreased CD34 and myogenin expression were observed. Alterations were partially attenuated by NaHCO3, while GCSF remarkably improved most parameters. The current results indicated that co-administration of GCSF and NaHCO3 could ameliorate CKD myopathy via attenuating oxidative stress, immunomodulation, pro-angiogenic ability, myocyte regeneration. In addition to the reduction of mitochondrial stress and maintenance of cellular homeostasis. [ABSTRACT FROM AUTHOR]

An 8-y-old National Show Horse mare was presented for evaluation of pneumonia and laminitis. Harsh bronchovesicular sounds were auscultated throughout both lung fields, and the mare had signs of moderately painful laminitis. Thoracic ultrasonography revealed lung consolidation throughout the dorsal aspect of both lungs, and radiography revealed an extensive diffuse-to-patchy bronchointerstitial lung pattern. The mare's clinical condition rapidly deteriorated, and euthanasia was elected. On postmortem examination, the lungs, omentum, spleen, liver, adrenal glands, kidneys, and femur contained 0.5–2.5-cm, firm, tan nodules. Histologically, the lungs, spleen, liver, kidneys, adrenal glands, omentum, left eye, and femur were infiltrated by bundles and nests of pleomorphic polygonal-to-spindloid cells intermixed with frequent multinucleate cells. Lymphatic vessels in the affected tissues were frequently distended with tumor emboli. Neoplastic cells were diffusely positive for vimentin, desmin, sarcomeric actin, myoblastic differentiation protein 1, and myogenin, supportive of the diagnosis of rhabdomyosarcoma (RMS), which is a rare neoplasm in horses. Cross-striations were not evident with H&E or phosphotungstic acid–hematoxylin stains. Markedly pleomorphic neoplastic cells, multinucleate cells, and lack of cross-striations suggested the subclassification of pleomorphic RMS. [ABSTRACT FROM AUTHOR]

(1) Background: the objective of this study was to examine the impact of defatted mealworm hydrolysate (DMH), formulated through protein hydrolysis, on muscle protein synthesis in C2C12 cells and rats; (2) Methods: C2C12 cells were treated with dexamethasone and DMH, and cell viability was quantified using the MTT assay. Twenty-four Sprague–Dawley rats were divided into three groups (control, DEX, and DEX + DMH) and treated for 8 weeks. The DEX and DEX + DMH groups were administered intraperitoneal injections of DEX at a concentration of 2.25 mg/kg over a 3-d period. The control and DEX groups were fed a control diet, whereas the DMH group had part of the protein composition of the control diet replaced with 3.5% of DMH. The impact of DMH on muscle protein synthesis was evaluated through the measurement of grip strength, gastrocnemius and tibialis anterior muscle weights, and the investigation of muscle protein synthesis and degradation factor mRNA expression utilising the real-time PCR method; (3) Results: in vitro experiments demonstrated that treatment with DMH at concentrations greater than 5 mg/mL markedly alleviated DEX-induced injury in C2C12 cells. In vivo experiments demonstrated that the mRNA expression levels of myogenin and myoblast determination proteins, which promote muscle protein synthesis, were significantly increased. Furthermore, rats fed DMH exhibited significantly enhanced grip strength and tibialis anterior weight; (4) Conclusions: these findings indicate that DMH may serve as a functional material capable of promoting muscle protein synthesis and that the utilization of proteolytic enzymes is advantageous for the effective utilization of mealworms. [ABSTRACT FROM AUTHOR]

Topmouth culter (Culter alburnus) is an important freshwater economic fish in China. However, external stress often triggers strong reactions, resulting in low survival rates and reduced productivity. The absence of stress-related genes has significantly limited our understanding of stress response in this fish. Therefore, 85,846,206 high-quality reads were acquired from kidney, liver and muscle cDNA libraries of topmouth culter using illumina sequencing technology in this study. Comparative analysis revealed that 3,158; 409 and 1,952 unigenes were specifically expressed in the kidney, liver and muscle transcriptome, respectively. Additionally, 83 crucial tissue-specific genes were identified within three stress-related GO terms: response to stimulus (GO:0050896), response to stress (GO:0006950) and response to hypoxia (GO:0001666). From these, 18 tissue-specific genes were further isolated. During the short-term stress experiment (two repeated handling stress, including chasing 2 min and netting out of water for 30s), significant changes were observed in the cortisol levels of both the treatment and recovery groups. Furthermore, notable changes were noted in the expression of LCP2, PTK2b and P-selectin genes in the kidney; FABP1, IGFBP1 and CYP4V2 genes in the liver; and MYH10, Myogenin 2 and Toponin C genes in the muscle of topmouth culter in the treatment and recovery groups (P < 0.05). The tissue-specific transcriptome profiles generated in this study offer valuable insights into the molecular and functional mechanisms associated with stress response in topmouth culter. We characterizated genes related to stress response in tissues such as the kidney, liver and muscle, these findings offer novel insights into stress research in fish. We can further explore the breeding of strains with enhanced stress resistance and promote the healthy development of topmouth culter industry. [ABSTRACT FROM AUTHOR]

Abstract Background Sarcopenia is a muscle disease characterized by reduction of muscle strength and muscle mass. In RA, 25.9 to 43.3% of the patients present sarcopenia. The loss of muscle mass observed in RA patients occurs either by activation of catabolic pathways or by inhibition of anabolic pathways. Despite having a list of drugs capable of treating RA inflammation, their effect on muscle is unclear. Our objective was to evaluate the tofacitinib effect on the muscle mass of collagen-induced arthritis (CIA) mice. Methods CIA was induced in male DBA/1J mice by subcutaneous injection of Type 2 Collagen plus Freund Adjuvant. Animals were randomized into 3 groups: CIA + tofacitinib; CIA + vehicle; and healthy controls. Treatment was administered twice a day, between days 18 and 45 after induction. Clinical score, edema, and body weight were evaluated during the experimental period. After euthanasia, tibiotarsal joints were collected for assessment of disease histopathological score, and tibialis anterior (TA) and gastrocnemius (GA) muscles were weighed to assess muscle mass. Muscle atrophy was evaluated by measurement of TA myofiber cross-sectional area (CSA). Protein expression was evaluated by western blot using GA homogenates. Serum inflammatory markers were evaluated by ELISA. Statistical analysis included ANOVA followed by Tukey’s or with Kruskal-Wallis. The statistical difference was assumed for p

The success of rotator cuff tendon repair relies on both tendon healing and muscle recovery. The objective of this descriptive study was to investigate the regenerative potential of the supraspinatus muscle in rotator cuff tear conditions by quantifying the expression of Pax7, MyoD, and myogenin, basic factors that regulate myogenesis. Muscle biopsies were collected from thirty-three patients aged 34 to 73 years who underwent surgery for a rotator cuff tear affecting the supraspinatus muscle. Among these patients, twenty-seven percent were women, and the age of the lesions ranged from 2 to 72 months post-initial trauma. Biopsies were harvested from the supraspinatus muscle at the end closest to the tendon, and control biopsies were harvested from the ipsilateral deltoid muscle. The densities of immunohistochemically stained Pax7+, MyoD+, and myogenin+ nuclei/mm2 were used to estimate the myogenic potential of the muscle. Adjustments were made for patient age and lesion age. We found increased density of MyoD+ and myogenin+ cells in supraspinatus muscles compared to deltoid muscles (p < 0.001 and p = 0.003, respectively). Regression analyses that combined the density of positive nuclei with patient age showed a continuous increase in Pax7 with age but also a reduction of MyoD and myogenin in older patients. When combined with lesion age, there was a decline in the density of all myogenic markers after an initial rise. Pax7 density continued to be higher in supraspinatus compared to the deltoid muscle, but the density of MyoD and myogenin terminally dropped to a density lower than in the deltoid. Our findings suggest that the supraspinatus muscle in tear conditions showed signs of initial activation of muscle regeneration. When compared to the unaffected deltoid muscle, an apparent reduction in capacity to progress to full muscle fiber maturity was also demonstrated. This pattern of inhibited myogenesis seemed to increase with both patient age and lesion age. Our results on muscle regenerative capacity indicate that younger patients with rotator cuff tears have better chances of muscle recovery and may benefit from early surgical reconstruction. [ABSTRACT FROM AUTHOR]

Introduction: The development and maintenance of the skeletal muscle is crucial for the support of daily function. Heat, when applied locally, has shown substantial promise in the maintenance of the muscle. The purpose of this study was to determine the combined effects of local heat application and acute resistance exercise on gene expression associated with the human muscle growth program. Materials and methods: Participants (n = 12, 26 ± 7 years, 1.77 ± 0.07 m, 79.6 ± 15.4 kg, and 16.1 ± 11.6 %BF) completed an acute bilateral bout of resistance exercise consisting of leg press (11 ± 2 reps; 170 ± 37 kg) and leg extension (11 ± 1 reps; 58 ± 18 kg). Participants wore a thermal wrap containing circulating fluid (40°C, exercise + heat; EX + HT) during the entire experimental period and 4 h post-exercise, while the other leg served as an exercise-only (EX) control. Biopsies of the vastus lateralis were collected (Pre, Post, and 4hPost) for gene expression analyses. Results: Intramuscular temperatures increased (Post, +2.2°C ± 0.7°C, and p < 0.001; 4hPost, +2.5°C ± 0.6°C, and p < 0.001) and were greater in the EX + HT leg post-exercise (+0.35°C ± 0.3°C, and p = 0.005) and after 4hPost (+2.1°C ± 0.8°C and p < 0.001). MYO-D1 mRNA was greater in the EX + HT leg vs. the EX (fold change = 2.74 ± 0.42 vs. 1.70 ± 0.28, p = 0.037). No other genes demonstrated temperature sensitivity when comparing both legs (p > 0.05). mRNA associated with the negative regulator, myostatin (MSTN), decreased post-exercise (p = 0.001) and after 4 h (p = 0.001). mRNA associated with proteolysis decreased post-exercise (FBXO32 , p = 0.001; FOXO3a , p = 0.001) and after 4 h (FBXO32, p = 0.001; FOXO3a , p = 0.027). Conclusion: The elevated transcription of the myogenic differentiation factor 1 (MYO-D1) after exercise in the heated condition may provide a mechanism by which muscle growth could be enhanced. [ABSTRACT FROM AUTHOR]

Abstract 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

Purpose: We investigated the effects of mouse-derived DFAT on the myogenic differentiation of a mouse-derived myoblast cell line (C2C12) and examined the therapeutic effects of rat-derived DFAT on anal sphincter injury using a rat model. Methods: C2C12 cells were cultured using DMEM and DFAT-conditioned medium (DFAT-CM), evaluating MyoD and Myogenin gene expression via RT-PCR. DFAT was locally administered to model rats with anorectal sphincter dysfunction 3 days post-CTX injection. Therapeutic effects were assessed through functional assessment, including anal pressure measurement using solid-state manometry pre/post-CTX, and on days 1, 3, 7, 10, 14, 17, and 21 post-DFAT administration. Histological evaluation involved anal canal excision on days 1, 3, 7, 14, and 21 after CTX administration, followed by hematoxylin–eosin staining. Results: C2C12 cells cultured with DFAT-CM exhibited increased MyoD and Myogenin gene expression compared to control. Anal pressure measurements revealed early recovery of resting pressure in the DFAT-treated group. Histologically, DFAT-treated rats demonstrated an increase in mature muscle cells within newly formed muscle fibers on days 14 and 21 after CTX administration, indicating enhanced muscle tissue repair. Conclusion: DFAT demonstrated the potential to enhance histological and functional muscle tissue repair. These findings propose DFAT as a novel therapeutic approach for anorectal sphincter dysfunction treatment. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

Introduction: Musculoskeletal injuries are widespread causes of sport injuries. Ordinary therapy is inadequate for rapid healing. So, in this study, the therapeutic effects of platelet rich plasma (PRP) were investigated as it is simple, efficient, and minimally invasive, and lessen recovery time. Materials and Methods: Fifty-four adult male albino rats, were categorizes into four groups: Group I (control group). Group II had a crush injury to the right gastrocnemius muscle, then sacrificed after 2 hours. Group III received no treatment and were subdivided into subgroups III A and III B, each includes 6 rats sacrificed after 7 and 14 days, respectively. Group IV, were injected immediately after injury by 0.1 ml PRP in injury site, then were subdivided into subgroups IV A and IV B, each includes 6 rats sacrificed after 7 and 14 days, respectively. Blood samples were analyzed for serum creatine phosphokinase (CPK) level. Sections from the middle part of the right gastrocnemius muscle were processed for histological assessment using H. and E., Masson trichrome stain, immunohistochemical staining for myogenin immunoreactivity, in addition to semithin and ultra-thin sections for light and electron microscopic examination, followed by morphometric and statistical studies. Results: Sections of group II showed disorganized, fragmented, discontinued, and tapering muscle fibers, disrupted Z discs at focal areas and giant disfigured mitochondria. The CPK level and mean number of myogenin immunoreactive nuclei and mean area percent of fibrous tissue were elevated, while the mean diameter of muscle fibers was decreased versus the control. Group III showed partial improvement, significant decrease in CPK level and increase in mean area percent of fibrous tissue, mean number of myogenin immunoreactive nuclei and in fiber diameter. Group IV showed prominent improvement. Conclusion: Platelet rich plasma could enhance repair of acutely crushed skeletal muscle and accelerate the healing process with minimal fibrosis. [ABSTRACT FROM AUTHOR]

IntroductionThe development and maintenance of the skeletal muscle is crucial for the support of daily function. Heat, when applied locally, has shown substantial promise in the maintenance of the muscle. The purpose of this study was to determine the combined effects of local heat application and acute resistance exercise on gene expression associated with the human muscle growth program.Materials and methodsParticipants (n = 12, 26 ± 7 years, 1.77 ± 0.07 m, 79.6 ± 15.4 kg, and 16.1 ± 11.6 %BF) completed an acute bilateral bout of resistance exercise consisting of leg press (11 ± 2 reps; 170 ± 37 kg) and leg extension (11 ± 1 reps; 58 ± 18 kg). Participants wore a thermal wrap containing circulating fluid (40°C, exercise + heat; EX + HT) during the entire experimental period and 4 h post-exercise, while the other leg served as an exercise-only (EX) control. Biopsies of the vastus lateralis were collected (Pre, Post, and 4hPost) for gene expression analyses.ResultsIntramuscular temperatures increased (Post, +2.2°C ± 0.7°C, and p < 0.001; 4hPost, +2.5°C ± 0.6°C, and p < 0.001) and were greater in the EX + HT leg post-exercise (+0.35°C ± 0.3°C, and p = 0.005) and after 4hPost (+2.1°C ± 0.8°C and p < 0.001). MYO-D1 mRNA was greater in the EX + HT leg vs. the EX (fold change = 2.74 ± 0.42 vs. 1.70 ± 0.28, p = 0.037). No other genes demonstrated temperature sensitivity when comparing both legs (p > 0.05). mRNA associated with the negative regulator, myostatin (MSTN), decreased post-exercise (p = 0.001) and after 4 h (p = 0.001). mRNA associated with proteolysis decreased post-exercise (FBXO32, p = 0.001; FOXO3a, p = 0.001) and after 4 h (FBXO32, p = 0.001; FOXO3a, p = 0.027).ConclusionThe elevated transcription of the myogenic differentiation factor 1 (MYO-D1) after exercise in the heated condition may provide a mechanism by which muscle growth could be enhanced.

(1) Background: the objective of this study was to examine the impact of defatted mealworm hydrolysate (DMH), formulated through protein hydrolysis, on muscle protein synthesis in C2C12 cells and rats; (2) Methods: C2C12 cells were treated with dexamethasone and DMH, and cell viability was quantified using the MTT assay. Twenty-four Sprague–Dawley rats were divided into three groups (control, DEX, and DEX + DMH) and treated for 8 weeks. The DEX and DEX + DMH groups were administered intraperitoneal injections of DEX at a concentration of 2.25 mg/kg over a 3-d period. The control and DEX groups were fed a control diet, whereas the DMH group had part of the protein composition of the control diet replaced with 3.5% of DMH. The impact of DMH on muscle protein synthesis was evaluated through the measurement of grip strength, gastrocnemius and tibialis anterior muscle weights, and the investigation of muscle protein synthesis and degradation factor mRNA expression utilising the real-time PCR method; (3) Results: in vitro experiments demonstrated that treatment with DMH at concentrations greater than 5 mg/mL markedly alleviated DEX-induced injury in C2C12 cells. In vivo experiments demonstrated that the mRNA expression levels of myogenin and myoblast determination proteins, which promote muscle protein synthesis, were significantly increased. Furthermore, rats fed DMH exhibited significantly enhanced grip strength and tibialis anterior weight; (4) Conclusions: these findings indicate that DMH may serve as a functional material capable of promoting muscle protein synthesis and that the utilization of proteolytic enzymes is advantageous for the effective utilization of mealworms.

Background. Spindle cell/sclerosing rhabdomyosarcoma is a rare neoplasm and has an aggressive clinical course. Because of its rarity, we performed a multi-institutional collaboration to comprehend the overarching clinical, histopathological, and immunohistochemical characteristics of a cohort of spindle cell/sclerosing rhabdomyosarcoma. Materials and Methods. Forty-five patients with spindle cell/sclerosing rhabdomyosarcoma were identified. Demographics, clinical, histopathological, and immunohistochemistry data were reviewed and recorded. Results. The patients' age ranged from 1 to 85 years with a male to female ratio of 1.2:1. There were 15 children/adolescents and 30 adults. Eighteen (40%) tumors were located in the head and neck region. Twenty-four (53%) tumors displayed a bimorphic cellular arrangement with hypercellular areas having short, long, and sweeping fascicular and herringbone pattern, and hypocellular areas with stromal sclerosis and associated hyalinized and/or chondromyxoid matrix. Histomorphological differentials considered were leiomyosarcoma, malignant peripheral nerve sheath tumor, fibrosarcoma, nodular fasciitis, liposarcoma, synovial sarcoma, sarcomatoid carcinoma, solitary fibrous tumor, dermatofibrosarcoma protuberans, and schwannoma. Six tumors exhibited marked stromal sclerosis. The myogenic nature was confirmed by immunohistochemistry. Positivity for at least one skeletal muscle-associated marker (MyoD1 and/or myogenin) was observed. Conclusion. Spindle cell/sclerosing rhabdomyosarcoma diagnosis can be challenging as a number of malignant spindle cell neoplasm mimic this entity. Thus a correct diagnosis requires immunohistochemical work up with a broad panel of antibodies. In view of rarity of this neoplasm, further studies on a large cohort of patients with clinical follow-up data are needed for a better understanding of this tumor. [ABSTRACT FROM AUTHOR]

The aims of current investigation were to study the growth performance, carcass traits, meat quality and expression profile of Myostatin (MSTN), Insulin-like growth factor-1 (IGF-I), Myogenin (MyoG) and Myogenic regulatory factor 4 (MRF4) genes in three commercial broiler strains including Ross (Ross 308), Cobb (Cobb 500), and Arian in 2023. A total number of 240 one-day-old chicks were reared under an equalized standard management condition for 6 weeks. Performance, organ weights, meat quality and the expression level of the myogenic genes in the pectoral muscle were investigated. The lowest body weight (BW), feed intake, weight gain and highest feed conversion ratio (FCR) was observed for Arian at the end of the study. The meat quality was similar between strains. The IGF-I expression level was significantly higher on 42 days of age in Cobb compared to Ross and Arian. The MRF4 expression level was significantly higher on 28 days of age in Cobb compared to Ross. The MyoG expression level was significantly lower in Arian compared to Cobb on 42 days of age. Furthermore, the MSTN expression level was significantly lower in Cobb compared to Ross and Arian on 42 days of age. The remarkable differences in gene expression levels at the end of the rearing period was supported by higher growth performance and BW of Cobb compared to Ross and Arian strains. In conclusion, the findings of current study could conveniently help assess the performance of these broiler strains under similar rearing condition. [ABSTRACT FROM AUTHOR]

Rhabdomyosarcoma (RMS) is the third most common extra-cranial sarcoma occurring in childhood, adolescents, and young adults (AYAs); and is rare in adults. Literature about RMS mainly considers RMS in AYAs, either with that in the children or adults, even though histological, molecular, and clinical characteristics of RMS in AYAs are significantly different from either of the two. Herein, we report a case of prostatic embryonal RMS, in a 17-year-old boy, along with the review of literature of prostatic RMS, with emphasis on AYAs. Our patient presented with clinical complaints of acute urinary retention, Grade IV prostatomegaly and, low serum prostate-specific-antigen (0.11ng/dl). The diagnosis was clinched by prostatic biopsy, which revealed diffuse 'small round blue cell' tumour admixed with larger rhabdomyoblasts, displaying positivity for desmin and myogenin, on immunohistochemistry. Clinicians should be mindful that RMS is found in all age groups ranging from childhood to adults; however, the clinical, histological, and molecular features are different. RMS in AYAs is often treated according to the guidelines provided for the paediatric age group. Treatment mostly comprises a multimodality approach, including surgery with/without chemo- and radiotherapy. Prognosis in AYAs is worse than in children but is better than in adults. Thus, early diagnosis gains utmost importance to provide comparatively more probability of rendering treatment and, hopefully, a better quality of life. [ABSTRACT FROM AUTHOR]

The rise in throughput and quality of long-read sequencing should allow unambiguous identification of full-length transcript isoforms. However, its application to single-cell RNA-seq has been limited by throughput and expense. Here we develop and characterize long-read Split-seq (LR-Split-seq), which uses combinatorial barcoding to sequence single cells with long reads. Applied to the C2C12 myogenic system, LR-split-seq associates isoforms to cell types with relative economy and design flexibility. We find widespread evidence of changing isoform expression during differentiation including alternative transcription start sites (TSS) and/or alternative internal exon usage. LR-Split-seq provides an affordable method for identifying cluster-specific isoforms in single cells.

Background: Skeletal muscle development during embryogenesis depends on proliferation of myoblasts followed by differentiation into myotubes/multinucleated myofibers. Vitamin D (VD) has been shown to affect these processes, but there is conflicting evidence within the current literature on the exact nature of these effects due to a lack of time course data. With 20%-40% of pregnant women worldwide being VD deficient, it is crucial that a clearer understanding of the impact of VD on myogenesis is gained. Methods: A detailed 8-day differentiation time course was used where C2C12 cells were differentiated in control media (2% horse serum) or with different concentrations of active VD, 1,25 (OH)2D3 (10-13 M, 10-11 M, 10-9M or 10-7 M), and measurements were taken at 6 time points. DNA, creatine kinase and protein assays were carried out as well as quantitative PCR to determine expression of Myf5, MyoD, myogenin, MHC I, and MHC neonatal, MHC embryonic, MHC IIa, MHC IIx, and MHC IIb mRNAs. Transfections were carried out using one vector containing the myogenin promoter and another containing the same promoter with a 3 base mutation within a putative vitamin D response element (VDRE) to determine effects of 1,25 (OH)2D3 on myogenin transcription. Finally, a ChIP assay was performed to determine whether the VD receptor (VDR) binds to the putative VDRE. Results: 1,25(OH)2D3 caused an inhibition of proliferation and an increase in differentiation in C2C12 cells. Myf5, myogenin, MHC I, and MHC neonatal, MHC embryonic, MHC IIa, MHC IIx, and MHC IIb expression were all increased by 1,25(OH)2D3. Myotube size was also increased by VD. When the putative VDRE on the myogenin promoter was mutated, the increase in expression by VD was lost. ChIP analysis revealed that the VDR does bind to the putative VDRE on the myogenin promoter. Conclusion: Active VD directly increases myogenin transcription via a functional VDRE on the myogenin promoter, resulting in increased myogenic differentiation, increased expression of both the early and late MHC isoforms, and also increased myotube size. These results highlight the importance of VD status during pregnancy for normal myogenesis to occur, but further in vivo work is needed. [ABSTRACT FROM AUTHOR]

Background: Alveolar rhabdomyosarcoma (ARMS) shows a predilection for the peripheral extremities and is very rarely identified as a primary in the brain. Here, we report a case of ARMS with multiple lesions exclusively within the central nervous system (CNS). Case Description: A 20-year-old man presented to our hospital with a gradually increasing headache and disturbance of consciousness. Neuroimaging showed hydrocephalus and multiple tumor lesions, including in the brainstem and cerebellum, with uniform gadolinium enhancement on T1-weighted magnetic resonance imaging, as well as spinal cord seeding. Cerebrospinal fluid (CSF) analysis showed a slightly elevated cell count (6/µL; normal, <5/µL) and highly elevated protein (153 mg/dL). In addition, atypical cells were cytologically identified in the CSF. No other laboratory findings were abnormal. Emergency ventricular drainage was performed to control cerebral pressure, followed by a biopsy to confirm the diagnosis. Histological examination revealed a fascicular arrangement of oval cells with eosinophilic cytoplasm and tumor cells with pleomorphic nuclei and prominent nucleoli. Immunohistochemical studies showed negative results for glial fibrillary acidic protein and positive results for desmin and myogenin. In addition, molecular analysis revealed that this tumor had the H3F3A p. Lys28Met mutation and no paired box (PAX)3-forkhead box O1 (FOXO1) or PAX7-FOXO1 fusion genes. ARMS was, therefore, diagnosed. Chemotherapy and radiotherapy were subsequently initiated, but tumor growth could not be controlled, and the patient died 6 months after surgery. Conclusion: This report describes an extremely rare case of ARMS arising exclusively within the CNS. [ABSTRACT FROM AUTHOR]

Background: Skeletal muscle development during embryogenesis depends on proliferation of myoblasts followed by differentiation into myotubes/multinucleated myofibers. Vitamin D (VD) has been shown to affect these processes, but there is conflicting evidence within the current literature on the exact nature of these effects due to a lack of time course data. With 20%–40% of pregnant women worldwide being VD deficient, it is crucial that a clearer understanding of the impact of VD on myogenesis is gained.Methods: A detailed 8-day differentiation time course was used where C2C12 cells were differentiated in control media (2% horse serum) or with different concentrations of active VD, 1,25 (OH)2D3 (10−13 M, 10−11 M, 10−9 M or 10−7 M), and measurements were taken at 6 time points. DNA, creatine kinase and protein assays were carried out as well as quantitative PCR to determine expression of Myf5, MyoD, myogenin, MHC I, and MHC neonatal, MHC embryonic, MHC IIa, MHC IIx, and MHC IIb mRNAs. Transfections were carried out using one vector containing the myogenin promoter and another containing the same promoter with a 3 base mutation within a putative vitamin D response element (VDRE) to determine effects of 1,25 (OH)2D3 on myogenin transcription. Finally, a ChIP assay was performed to determine whether the VD receptor (VDR) binds to the putative VDRE.Results: 1,25(OH)2D3 caused an inhibition of proliferation and an increase in differentiation in C2C12 cells. Myf5, myogenin, MHC I, and MHC neonatal, MHC embryonic, MHC IIa, MHC IIx, and MHC IIb expression were all increased by 1,25(OH)2D3. Myotube size was also increased by VD. When the putative VDRE on the myogenin promoter was mutated, the increase in expression by VD was lost. ChIP analysis revealed that the VDR does bind to the putative VDRE on the myogenin promoter.Conclusion: Active VD directly increases myogenin transcription via a functional VDRE on the myogenin promoter, resulting in increased myogenic differentiation, increased expression of both the early and late MHC isoforms, and also increased myotube size. These results highlight the importance of VD status during pregnancy for normal myogenesis to occur, but further in vivo work is needed.

INTRODUCTION: We conducted an open-label study to examine the effects of the flavonoid (-)-epicatechin in seven ambulatory adult patients with Becker muscular dystrophy (BMD). METHODS: Seven participants received (-)-epicatechin 50 mg twice per day for 8 weeks. Pre- and postprocedures included biceps brachii biopsy to assess muscle structure and growth-relevant endpoints by western blotting, mitochondria volume measurement, and cristae abundance by electron microscopy, graded exercise testing, and muscle strength and function tests. RESULTS: Western blotting showed significantly increased levels of enzymes modulating cellular bioenergetics (liver kinase B1 and 5-adenosine monophosphate-activated protein kinase). Peroxisome proliferator-activated receptor gamma coactivator-1alpha, a transcriptional coactivator of genes involved in mitochondrial biogenesis and cristae-associated mitofilin levels, increased as did cristae abundance. Muscle and plasma follistatin increased significantly while myostatin decreased. Markers of skeletal muscle regeneration myogenin, myogenic regulatory factor-5, myoblast determination protein 1, myocyte enhancer factor-2, and structure-associated proteins, including dysferlin, utrophin, and intracellular creatine kinase, also increased. Exercise testing demonstrated decreased heart rate, maximal oxygen consumption per kilogram, and plasma lactate levels at defined workloads. Tissue saturation index improved in resting and postexercise states. DISCUSSION: (-)-Epicatechin, an exercise mimetic, appears to have short-term positive effects on tissue biomarkers indicative of mitochondrial biogenesis and muscle regeneration, and produced improvements in graded exercise testing parameters in patients with BMD.

Skeletal muscle maintenance depends largely on muscle stem cells (satellite cells) that supply myoblasts required for muscle regeneration and growth. The ubiquitin–proteasome system is the major intracellular protein degradation pathway. We previously reported that proteasome dysfunction in skeletal muscle significantly impairs muscle growth and development. Furthermore, the inhibition of aminopeptidase, a proteolytic enzyme that removes amino acids from the termini of peptides derived from proteasomal proteolysis, impairs the proliferation and differentiation ability of C2C12 myoblasts. However, no evidence has been reported on the role of aminopeptidases with different substrate specificities on myogenesis. In this study, therefore, we investigated whether the knockdown of aminopeptidases in differentiating C2C12 myoblasts affects myogenesis. The knockdown of the X‐prolyl aminopeptidase 1, aspartyl aminopeptidase, leucyl‐cystinyl aminopeptidase, methionyl aminopeptidase 1, methionyl aminopeptidase 2, puromycine‐sensitive aminopeptidase, and arginyl aminopeptidase like 1 gene in C2C12 myoblasts resulted in defective myogenic differentiation. Surprisingly, the knockdown of leucine aminopeptidase 3 (LAP3) in C2C12 myoblasts promoted myogenic differentiation. We also found that suppression of LAP3 expression in C2C12 myoblasts resulted in the inhibition of proteasomal proteolysis, decreased intracellular branched‐chain amino acid levels, and enhanced mTORC2‐mediated AKT phosphorylation (S473). Furthermore, phosphorylated AKT induced the translocation of TFE3 from the nucleus to the cytoplasm, promoting myogenic differentiation through increased expression of myogenin. Overall, our study highlights the association of aminopeptidases with myogenic differentiation. [ABSTRACT FROM AUTHOR]

Various pathological alterations, including lipid-deposition-induced comparative cardiac lipotoxicity, contribute to cardiac aging in the failing heart. A decline in endogenous myogenin proteins can lead to the reversal of muscle cell differentiation and the creation of mononucleated muscle cells. Myogenin may be a specific regulator of adaptive responses to avoid pathological hypertrophy in the heart. Hence, it is important to understand the regulation of myogenin expression and functions in response to exposure to varied stresses. In this study, we first examined and verified the cytotoxic effect of palmitic acid on H9c2 cells. The reduction in myogenin mRNA and protein expression by palmitic acid was independent of the effect of glucose. Meanwhile, the induction of cyclooxygenase 2 and activating transcription factor 3 mRNAs and proteins by palmitic acid was dependent on the presence of glucose. In addition, palmitic acid failed to disrupt cell cycle progression when H9c2 cells were treated with no glucose. Next, we examined the functional role of myogenin in palmitic-acid-treated H9c2 cells and found that myogenin may be involved in palmitic-acid-induced mitochondrial and cytosolic ROS generation, cellular senescence, and mitochondrial membrane potential. Finally, the GSE150059 dataset was deposited in the Gene Expression Omnibus website and the dataset was further analyzed via the molecular microscope diagnostic system (MMDx), demonstrating that many heart transplant biopsies currently diagnosed as no rejection have mild molecular-antibody-mediated rejection-related changes. Our data show that the expression levels of myogenin were lower than the average level in the studied population. Combining these results, we uncover part of the functional role of myogenin in lipid- and glucose-induced cardiac cell stresses. This finding provides valuable insight into the differential role of fatty-acid-associated gene expression in cardiovascular tissues. Additionally, the question of whether this gene expression is regulated by myogenin also highlights the usefulness of a platform such as MMDx-Heart and can help elucidate the functional role of myogenin in heart transplantation. [ABSTRACT FROM AUTHOR]

Abstract Background Skeletal muscle contractions due to exercise lead to the secretion of many proteins and proteoglycan peptides called myokines. Myostatin (MSTN) and Myogenin (MyoG) are two of the most important skeletal muscle growth regulatory factors related to myoblast differentiation and muscle hypertrophy. The present study aims at investigating the effects over eight weeks of high-intensity circuit training (HICT) on serum MyoG and MSTN in male soccer players. Method The present study is a quasi-experimental study on 21 male soccer players (Experimental group: n = 11, Control group: n = 10) (ages 15.0 ± 3.4 years, body mass 55.7 ± 7.8 kg, height 173.3 ± 8.0 cm, Body mass index 18.4 ± 1.9 kg m−2, maximum oxygen uptake 61.89 ± 3.01 ml kg−1 and the peak height velocity 14.5 ± 0.3 years). Participants were randomly divided into two groups: training group and a control group. The first resting blood samples were obtained in the morning-fasting state, and the second blood samples were obtained after the maximum aerobic test at pre- and post-HICT. Results There were non-significant differences in resting serum values of MyoG (p = 0.309, p > 0.05) but significant differences in resting serum values of MSTN between the training and control groups after eight weeks of HICT (p = 0.003, p

Abstract Background Muscle atrophy, leading to muscular dysfunction and weakness, is an adverse outcome of sustained period of glucocorticoids usage. However, the molecular mechanism underlying this detrimental condition is currently unclear. Pyruvate dehydrogenase kinase 4 (PDK4), a central regulator of cellular energy metabolism, is highly expressed in skeletal muscle and has been implicated in the pathogenesis of several diseases. The current study was designed to investigated and delineate the role of PDK4 in the context of muscle atrophy, which could be identified as a potential therapeutic avenue to protect against dexamethasone‐induced muscle wasting. Methods The dexamethasone‐induced muscle atrophy in C2C12 myotubes was evaluated at the molecular level by expression of key genes and proteins involved in myogenesis, using immunoblotting and qPCR analyses. Muscle dysfunction was studied in vivo in wild‐type and PDK4 knockout mice treated with dexamethasone (25 mg/kg body weight, i.p., 10 days). Body weight, grip strength, muscle weight and muscle histology were assessed. The expression of myogenesis markers were analysed using qPCR, immunoblotting and immunoprecipitation. The study was extended to in vitro human skeletal muscle atrophy analysis. Results Knockdown of PDK4 was found to prevent glucocorticoid‐induced muscle atrophy and dysfunction in C2C12 myotubes, which was indicated by induction of myogenin (0.3271 ± 0.102 vs 2.163 ± 0.192, ****P

Mammalian SWI/SNF (mSWI/SNF) complexes are ATP-dependent chromatin remodeling enzymes that are critical for normal cellular functions. mSWI/SNF enzymes are classified into three sub-families based on the presence of specific subunit proteins. The sub-families are Brm- or Brg1-associated factor (BAF), ncBAF (non-canonical BAF), and polybromo-associated BAF (PBAF). The biological roles for the different enzyme sub-families are poorly described. We knocked down the expression of genes encoding unique subunit proteins for each sub-family, Baf250A, Brd9, and Baf180, which mark the BAF, ncBAF, and PBAF sub-families, respectively, and examined the requirement for each in myoblast differentiation. We found that Baf250A and the BAF complex were required to drive lineage-specific gene expression. KD of Brd9 delayed differentiation. However, while the Baf250A-dependent gene expression profile included myogenic genes, the Brd9-dependent gene expression profile did not, suggesting Brd9 and the ncBAF complex indirectly contributed to differentiation. Baf180 was dispensable for myoblast differentiation. The results distinguish between the roles of the mSWI/SNF enzyme sub-families during myoblast differentiation. [ABSTRACT FROM AUTHOR]

Objective: Rare disease Background: Leiomyosarcoma is the most common uterine sarcoma. Leiomyosarcoma is classified into conventional leiomyosarcoma, epithelioid leiomyosarcoma, and myxoid leiomyosarcoma. Leiomyosarcomas with rhabdoid features have been rarely reported. Herein, we report a case of uterine leiomyosarcoma with rhabdoid features. Case Report: A 58-year-old Korean woman presented with acute abdominal pain. Computed tomography and magnetic resonance imaging of the pelvis revealed a large solid mass in the posterior wall of the uterus that extended to the uterine cervix. The patient underwent total hysterectomy with bilateral salpingo-oophorectomy and tumorectomy. Microscopic and immunohistochemical examination of the tumor revealed leiomyosarcoma with rhabdoid features and high proliferation rate. Next-generation sequencing showed PI3K amplification and ERBB2 amplification. Postoperative abdominal and pelvic computed tomography performed 3 weeks after the operation showed a mass at the vaginal stump that was attached to the urinary bladder and rectum. The patient underwent pelvic exenteration of remnant vaginal stump, rectum, and urinary bladder with loop ileostomy, and was diagnosed with recurrent leiomyosarcoma. One month later, after the second operation, a 13-cm recurrent mass was noted on the computed tomography. Chemotherapy was not done and the patient died during supportive treatment 7 months after diagnosis. Conclusions: This case, which is a uterine leiomyosarcoma with rhabdoid features and high proliferation rate, recurred very fast, within 1 month, and showed an aggressive clinical course. The molecular classification and postoperative therapy are not well established in uterine leiomyosarcomas. Further studies are required to clarify the clinical and pathological characteristics of leiomyosarcomas. [ABSTRACT FROM AUTHOR]

Pemphigus Vulgaris (PV) is a blistering autoimmune disease caused by autoantibodies against desmoglein 1 and 3. Treatment options are limited to corticosteroids and immunosuppressants. The myotoxic effect of glucocorticoids is a fact that has been elucidated. So, the development of efficacious treatment approaches to combat muscle wasting is of great importance. Considering the adverse effect of glucocorticoid therapy in pemphigus patients and altered muscle metabolism, this study aimed to investigate the effect of l‐carnitine supplementation which can be useful in combating muscle‐wasting impact of glucocorticoid therapy. In this randomized double‐blind placebo‐controlled trial 44 pemphigus patients aged from 30 to 65 years, receiving glucocorticoid therapy were selected to evaluate the suitability of l‐carnitine (LC) as an anti‐wasting substance. Patients were randomly divided into two groups to receive 2 g/d l‐carnitine or placebo for 8 weeks; serum markers of muscle metabolism (IGF‐1, creatine kinase, myogenin, myostatin) was evaluated before and after the l‐carnitine supplementation. Paired T‐test was used to analyze the differences between variables before and after the intervention. Therefore, the student's t‐test was performed to find any differences in baseline characteristics and dietary intakes between the trial groups. LC intake led to a significant rise in serum IGF‐1 and a reduction in CK and myostatin levels compared to baseline (p < 0.05) but there were no significant inter‐group differences in IGF‐1 and CK levels; There was also a significant reduction in myostatin level in LC group (p < 0/05). Myogenin levels decreased in both LC and placebo groups but the decrease in the placebo group was significant (p = 0/008); it means LC prevent the myogenin decreasing trend in the LC group compared to placebo. In conclusion, LC supplementation beneficially changes the level of IGF‐1 and myostatin and improves muscle metabolism and regeneration in PV patients. [ABSTRACT FROM AUTHOR]

Rhabdomyosarcoma (RMS), a malignant mesenchymal neoplasm derived from skeletal muscle, is relatively rare in both human and veterinary medicine. Here we report an unusual case of invasive spindle-cell RMS (SCRMS) with bone infiltration and pathologic fracture in a 3.5-y-old intact female Bulldog. Radiographically, a large, predominantly osteolytic mass in the tibia and fibula of the left hindlimb had features typical of a malignant primary bone tumor. Clinically, osteosarcoma was suspected, and the leg was amputated. Histologically, the mass was composed of loosely interwoven spindle-cell fascicles; tumor cells were fusiform with cigar-shaped nuclei and abundant eosinophilic cytoplasm. The neoplastic cells were strongly immunopositive for vimentin, muscle-specific actin, desmin, myogenin, and myoD1. Invasive SCRMS with osteolysis was diagnosed based on the histologic examination and immunohistochemical (IHC) stains. The dog was alive without any evidence of local recurrence or distant metastasis 18 mo post-surgery. RMS should be included in the differential diagnosis when osteolysis occurs; IHC staining confirmation is of great value for definitive diagnosis and treatment planning. [ABSTRACT FROM AUTHOR]

Background: Myogenin is well known as a crucial transcription factor in skeletal muscle development, yet its other biological functions remain unexplored. Previous research showed that myogenin suppresses apoptosis induced by angiotensin II in human induced pluripotent stem cell-derived cardiomyocytes, and offered a new perspective on myogenin’s role in cardioprotection. However, the detailed mechanism of this cardioprotection, especially under oxidative stress, is still unclear. Methods: In this study, hydrogen peroxide (H2O2) was used to generate reactive oxygen species in myogenin-overexpressing cardiomyocytes. The apoptosis was examined by flow cytometry. Transcriptome sequencing (RNA-seq) was performed to identify genes regulated by myogenin. Western blotting was used to detect the protein level of DUSP13 and the phosphorylation level of p38 mitogen-activated protein kinase (MAPK). The dual-luciferase reporter assay and ChIP assay were used to confirm the binding of myogenin to the promoter region of DUSP13. DUSP13 overexpression and knockdown assays were performed to study its anti-apoptotic role. Results: Flow cytometry analysis of apoptosis showed that overexpressing myogenin for 24 and 48 hours decreased the apoptotic ratio by 47.9% and 63.5%, respectively, compared with untreated controls. Transcriptome sequencing performed on cardiomyocytes that expressed myogenin for different amounts of time (6, 12, 24, and 48 hours) identified DUSP13 as being up-regulated by myogenin. Western blotting showed that overexpression of myogenin increased the expression of DUSP13 and decreased the phosphorylation level of p38 MAPK. A dual-luciferase reporter assay proved that myogenin bound directly to the promoter region of DUSP13 and led to strong relative luciferase activity. Direct expression of DUSP13A and DUSP13B significantly reduced the rates of apoptosis and necrosis in cells treated with H2O2. Knockdown of DUSP13B significantly increased the rate of apoptosis in cells treated with H2O2. Conclusions: The present findings suggest that myogenin might attenuate apoptosis induced by reactive oxygen species by up-regulating DUSP13 and inactivating the p38 MAPK pathway.

Background: Skeletal muscle contractions due to exercise lead to the secretion of many proteins and proteoglycan peptides called myokines. Myostatin (MSTN) and Myogenin (MyoG) are two of the most important skeletal muscle growth regulatory factors related to myoblast differentiation and muscle hypertrophy. The present study aims at investigating the effects over eight weeks of high-intensity circuit training (HICT) on serum MyoG and MSTN in male soccer players. Method: The present study is a quasi-experimental study on 21 male soccer players (Experimental group: n = 11, Control group: n = 10) (ages 15.0 ± 3.4 years, body mass 55.7 ± 7.8 kg, height 173.3 ± 8.0 cm, Body mass index 18.4 ± 1.9 kg m−2, maximum oxygen uptake 61.89 ± 3.01 ml kg−1 and the peak height velocity 14.5 ± 0.3 years). Participants were randomly divided into two groups: training group and a control group. The first resting blood samples were obtained in the morning-fasting state, and the second blood samples were obtained after the maximum aerobic test at pre- and post-HICT. Results: There were non-significant differences in resting serum values of MyoG (p = 0.309, p > 0.05) but significant differences in resting serum values of MSTN between the training and control groups after eight weeks of HICT (p = 0.003, p < 0.05). No significant differences were observed between groups in the acute response of serum values of MyoG (p = 0.413, p < 0.05) and MSTN (p = 0.465, p < 0.05) to the maximum aerobic test after eight weeks of HICT. Conclusion: These results suggest that eight weeks of HICT can decrease the resting serum values of MSTN but not change the resting serum values of MyoG in male adolescent soccer players. Also, eight weeks of HICT does not affect the acute response of MSTN and MyoG after a maximum aerobic test. [ABSTRACT FROM AUTHOR]

Simple Summary: Nutrition affects all interactions of the body, especially the genome and the expression of genes. All organisms are always feeding, and life is not possible without nutrition. Origanum majorana (MO) is one nutritional additive and has many useful properties, such as antioxidant, antibacterial and antifungal properties. On the other hand, myogenin is a protein in the myogenic regulatory factor family that plays an important role in determining carcass and meat traits and is vital for the growth and development of livestock muscles. As the results of the current study show, MO might be applied in the diets of lambs in order to improve the parameters related to growth via useful reactions on myogenin gene expression. Myogenin is a protein in the myogenic regulatory factor family that plays an important role in determining carcass and meat traits and is vital for the growth and development of livestock muscles. The objective of this study was to determine the impact of Origanum majorana leaf (MOL) on the myogenin gene expression of lambs. Twenty-four male Kermani lambs were used in a completely randomized design using two experimental groups (0% Origanum majorana L. = MOL0 and 4% Origanum majorana L. = MOL4). Final weight, average daily gain, hot and cold carcass weight, feed conversion ratio, empty body weight, hot and cold dressing percentage, the weight of the shoulder, loin, leg, and lean meat, and the lean/bone ratio were measured. A standard kit was used for extracting total RNA from the loin, leg, and shoulder muscles of the lambs' tissues. The cDNA was synthesized, a real-time PCR was performed, and the obtained data were analyzed. The results of this study showed that the effect of MOL4 on dry matter intake is not significant. The MOL4 diet increased final weight by 8.22%, average daily gain by 28.57%, hot carcass weight by 11.38%, cold carcass weight by 13.43%, feed conversion ratio by 31.03%, empty body weight by 9.38%, hot dressing percentage by 2.92%, cold dressing percentage by 3.75%, shoulder weight by 56.70%, loin weight by 8.98%, leg weight by 10.90%, lean meat weight by 14.62%, and the lean/bone ratio by 2.85% (p < 0.05) compared to the MOL0. Along with adding MOL4 in the lambs' diets, in comparison with MOL0, there was higher expression of myogenin in the loin (3.5 times), leg (3.9 times), and shoulder (3.6 times) muscles of the lambs. Due to the fact that adding Origanum majorana to the diet of the lambs enhanced the expression of the myogenin gene in the loin, leg, and shoulder muscles and increased parameters related to growth, it can be used to improve the parameters related to growth and to increase myogenin gene expression in the muscle of lambs. [ABSTRACT FROM AUTHOR]

Hyperphosphatemia can occur as a result of reduced phosphate (Pi) excretion in cases of kidney dysfunction, which can induce muscle wasting and suppress myogenic differentiation. Higher Pi suppresses myogenic differentiation and promotes muscle atrophy through canonical (oxidative stress-mediated) and noncanonical (p62-mediated) activation of nuclear factor erythroid 2-related factor 2 (Nrf2) signaling. However, the crosstalk between myogenin and Nrf2/p62 and potential drug(s) for the regulation of myogenin expression needed to be addressed. In this study, we further identified that myogenin may negatively regulate Nrf2 and p62 protein levels in the mouse C2C12 muscle cell line. In the drug screening analysis, we identified N-acetylcysteine, metformin, phenformin, berberine, 4-chloro-3-ethylphenol, cilostazol, and cilomilast as ameliorating the induction of Nrf2 and p62 expression and reduction in myogenin expression that occur due to high Pi. We further elucidated that doxorubicin and hydrogen peroxide reduced the amount of myogenin protein mediated through the Kelch-like ECH-associated protein 1/Nrf2 pathway, differently from the mechanism of high Pi. The dual functional roles of L-ascorbic acid (L-AA) were found to be dependent on the working concentration, where concentrations below 1 mM L-AA reversed the effect of high Pi on myogenin and those above 1 mM L-AA had a similar effect of high Pi on myogenin when used alone. L-AA exacerbated the effect of hydrogen peroxide on myogenin protein and had no further effect of doxorubicin on myogenin protein. In summary, our results further our understanding of the crosstalk between myogenin and Nrf2, with the identification and verification of several potential drugs that can be applied in rescuing the decline of myogenin due to high Pi in muscle cells. [ABSTRACT FROM AUTHOR]

In animal breeding, selection based on growth is very often used, as this trait affects the profitability of animal production. Identification of polymorphisms within the genes affecting the growth process seems to be very important. Therefore, we decided to analyse rabbit myogenin (MyoG gene) for potential polymorphic sites and their association with growth and carcass traits in Termond White (TER), Belgian Giant Grey (BGG) and crossbred New Zealand White×Belgian Giant Grey (NZW×BGG) rabbits. We found three single nucleotide polymorphisms (SNPs) – in 5’ upstream sequence g.68679476 C>T, in exon 1 – silent mutation g.68680096 T>C and g.68680097 G>A resulting in change of GTG triplet (valine) into ATG triplet (methionine). Association analysis showed that GG genotype weaning weight was statistically higher compared to GA in TER population (P=0.005), and that the hind parts for GG genotypes were heavier compared to those of GA (P=0.024), but association analysis of dissectible parts showed this was caused by higher bone weight (P=0.015). For g.68679476 C>T in NZW×BGG population, the CC genotypes for fore (678±35) and hind part (615±29) weights were heavier compared to CT (588±16 and 549±13, respectively); moreover, association analysis of dissectible parts showed that weight of dissectible meat in hind part. Unfortunately, we did not find similar associations for other analysed breeds. For g.68679476 C>T in NZWxBGG musculus longissimus lumborum pH leg after 24 h chilling (pH24L) were statistically lower for CC genotypes compared to CT (P=0.027). For g.68680097 G>A in Termond White population L* value on the hind leg after 24 h chilling (L*24H) was higher for GA genotypes compared to GG (P=0.03), while for g.68679476 C>T for musculus longissimus lumborum L* value after 24 h (L*24L) CC genotypes had higher value compared to CT (P=0.016) in BGG population. Moreover, in BGG population CT genotypes had higher weaning weight compared to CC (P=0.018). Our results show that SNPs within the MyoG gene may influence growth traits in some rabbit breeds, but the evolutionary conserved sequence may not be favourable for changes within coding sequences. For a better understanding thereof, additional analysis is required.

Trichinosis is a common parasitic disease that affects the striated skeletal muscles, causing apoptotic and degenerative changes associated with myogenin expression in the affected myocytes. Hence, this study aimed to assess the ameliorative effects of stem cells and atorvastatin added to ivermectin on the infected myocytes during the muscular phase of murine trichinosis. 120 laboratory Swiss albino male mice were divided into 10 groups, and each group was subdivided into intestinal and muscular phases (each n = 6); uninfected control; untreated infected control; infected received ivermectin monotherapy; infected received atorvastatin monotherapy; infected received stem cells monotherapy; infected received ivermectin and atorvastatin dual therapy; infected received ivermectin and stem cells dual therapy; infected received atorvastatin and stem cells dual therapy; infected received ivermectin 0.2, atorvastatin 40, and stem cells triple therapy; and infected received ivermectin 0.1, atorvastatin 20, and stem cells triple therapy. Intestinal phase mice were sacrificed on the 5th day post-infection, while those of the muscular phase were sacrificed on the 35th day post-infection. Parasitological, histopathological, ultrastructural, histochemical, biochemical, and myogenin gene expression assessments were performed. The results revealed that mice that received ivermectin, atorvastatin, and stem cell triple therapies showed the maximum reduction in the adult worm and larvae burden, marked improvement in the underlying muscular degenerative changes (as was noticed by histopathological, ultrastructural, and histochemical Feulgen stain assessment), lower biochemical levels of serum NK-κB and tissue NO, and lower myogenin expression. Accordingly, the combination of stem cells, atorvastatin, and ivermectin affords a potential synergistic activity against trichinosis with considerable healing of the underlying degenerative sequel. [Display omitted] • Ivermectin, atorvastatin, and stem cell triple therapies showed the maximum reduction in the adult worm and larvae burden. • Marked improvement in the underlying muscular degenerative changes was observed with triple therapy. • Lower biochemical levels of serum NK-κB and tissue NO, and lower myogenin expression were noticed with triple therapy. • IVM has augmented therapeutic activity against trichinosis when combined with Ator and SCs. [ABSTRACT FROM AUTHOR]

A 10‐week feeding trial was conducted to evaluate the effects of dietary replacement of fish oil (FO) with black soldier fly larvae oil (BSFLO) and vegetable oils, namely moringa oil (MO), black cumin seed oil (BCSO) and flax seed oil (FSO) on growth and whole‐body fatty acid profile, digestive enzyme activity, haemato‐biochemical responses and muscle growth‐related gene expression of juvenile striped catfish, Pangasianodon hypophthalmus. Five isonitrogenous (313.34 g kg−1) and isolipidic (81.82 g kg−1) experimental diets were formulated. A total of 450 fingerlings (5.02 ± 0.1 g per fish) were randomly distributed into 15 tanks and fed thrice a day. The final weight gain was significantly improved in fish fed FO (45.7 ± 0.72 g/fish), BSFLO (45.53 ± 1.32 g/fish) and MO diet (47.2 ± 0.26 g/fish) when compared to BCSO (36.3 ± 1.05 g/fish) and FSO (35.83 ± 0.71g/ fish) diets. The lower value of daily weight gain was recorded in the FSO and BCSO treatments compared with other oils could be due to effects on stress resistance and immunosuppression in fish, whereas the whole‐body EPA and DHA content of fish fed with FSO and FO diets was substantially higher than fish fed with other experimental diets. However, the relative expression of Myo D and Myogenin was upregulated in fish fed with FO, BSFLO and MO diet than the BCSO and FSO diet. Present results indicate that the juveniles can be reared on diets in which FO has been replaced with BSFLO and MO, with no significant effects on fish performance. [ABSTRACT FROM AUTHOR]

Ubiquitin-specific protease 8 (USP8), a member of the ubiquitin-specific protease (USP) family, was originally identified as playing a role in the regulation of growth and cell cycle. However, its functional role in myogenesis is unknown. In this study, we investigated the role of USP8 in proliferation and differentiation of sheep skeletal muscle satellite cells. The results showed that the expression level of USP8 was significantly increased on days 2 and 3 following the induction of the differentiation process. Furthermore, knocking down USP8 resulted in a significant increase in myogenin-positive cells, and promoted early differentiation of satellite cells by regulating the expression level of paired box 7 (PAX7). Additionally, knocking down USP8 suppressed muscle satellite cell proliferation, possibly explaining that the relative mRNA level of USP8 was linearly related to muscle fibre density of Hu sheep. Overall, our research demonstrates that USP8 plays a role in proliferation and early differentiation of skeletal muscle satellite cells.

Inflammatory rhabdomyoblastic tumor (IRMT), previously called histiocyte-rich rhabdomyoblastic tumor (HRRMT), is a recently described skeletal muscle neoplasm of uncertain malignant potential, commonly affecting young-to-middle aged men, typically arises in the skeletal muscles of the lower extremities and trunk and mostly has an intermediate (rarely metastasizing) clinical behavior. IRMT/HRRMT is commonly characterized by slow growth and encapsulation containing lymphoid aggregates. It is composed of spindle-to-epithelioid cells with a rhabdomyoblastic immunophenotype, a diffuse histiocytic infiltrate, and low mitotic figures. In this review, we will summarize its clinicopathologic features, immunophenotypic and molecular findings, prognosis, and treatment based on currently available published case reports. The purpose of this review is to increase awareness of this rare entity among pathologists and further help clinicians to manage patients properly.

Abstract Background Myogenin is a transcription factor that is expressed during terminal myoblast differentiation in embryonic development and adult muscle regeneration. Investigation of this cell state transition has been hampered by the lack of a sensitive reporter to dynamically track cells during differentiation. Results Here, we report a knock-in mouse line expressing the tdTOMATO fluorescent protein from the endogenous Myogenin locus. Expression of tdTOMATO in Myog ntdTom mice recapitulated endogenous Myogenin expression during embryonic muscle formation and adult regeneration and enabled the isolation of the MYOGENIN + cell population. We also show that tdTOMATO fluorescence allows tracking of differentiating myoblasts in vitro and by intravital imaging in vivo. Lastly, we monitored by live imaging the cell division dynamics of differentiating myoblasts in vitro and showed that a fraction of the MYOGENIN+ population can undergo one round of cell division, albeit at a much lower frequency than MYOGENIN− myoblasts. Conclusions We expect that this reporter mouse will be a valuable resource for researchers investigating skeletal muscle biology in developmental and adult contexts.

A 10‐week feeding trial was conducted to determine the effects of dietary black soldier fly larval meal (BSFLM) on growth performances, digestive enzyme activity, haematological responses and muscle growth‐related gene expression of juvenile striped catfish (Pangasianodon hypophthalmus). Six isonitrogenous and isolipidic diets were formulated with BSFLM to replace fishmeal at 0 per cent (T0), 20 per cent (T20), 40 per cent (T40), 60 per cent (T60), 80 per cent (T80) and 100 per cent (T100). A total of 540 fingerlings were randomly distributed into 18 tanks and fed thrice a day. Growth performance and feed utilization of fish fed T20, T40 and T60 diets were not significantly different from T0 diet. However, increasing the percentage of fishmeal replacement with BSFLM to 100% at an inclusion level of 292 g/kg resulted in a substantial reduction in growth and feed efficiency of striped catfish. Fish fed T80 and T100 diets had significantly lower whole‐body crude protein, crude lipid, total cholesterol and triglyceride value than fish fed other experimental diets, while dietary inclusion of BSFLM had no significant effect on the whole‐body amino acid profile, haematological responses and intestinal and liver protease and amylase activity of striped catfish. However, lipase activity was increased in fish fed T80 and T100 diets. T80 and T100 hepatocytes were shown to have greater congestion in histology than other groups. The relative expression of MyoD and myogenin was significantly maximized in fish fed the T60 diet. Fishmeal may be replaced with BSFLM up to 60 per cent at an inclusion level of 174 g/kg in the diet of juvenile striped catfish. [ABSTRACT FROM AUTHOR]

Objective: Paravertebral muscle asymmetry may be involved in the pathogenesis of adolescent idiopathic scoliosis (AIS), and the Tent5a protein was recently identified as a novel active noncanonical poly(A) polymerase. We, therefore, explored the function of the AIS susceptibility gene Tent5a in myoblasts. Materials and methods: RNA‐seq of AIS paravertebral muscle was performed, and the molecular differences in paravertebral muscle were investigated. Twenty‐four AIS susceptibility genes were screened, and differential expression of Tent5a in paravertebral muscles was confirmed with qPCR and Western blot. After the knockdown of Tent5a, the functional effects of Tent5a on C2C12 cell proliferation, migration, and apoptosis were detected by Cell Counting Kit‐8 assay, wound‐healing assay, and TUNEL assay, respectively. Myogenic differentiation markers were tested with immunofluorescence and qPCR in vitro, and muscle fiber formation was compared in vivo. Results: The AIS susceptibility gene Tent5a was differentially expressed in AIS paravertebral muscles. Tent5a knockdown inhibited the proliferation and migration of C2C12 cells and inhibited the maturation of type I muscle fibers in vitro and in vivo. Mechanistically, the expression of myogenin was decreased along with the suppression of Tent5a. Conclusions: Tent5a plays an important role in the proliferation and migration of myoblasts, and it regulates muscle fiber maturation by maintaining the stability of myogenin. Tent5a may be involved in the pathogenesis of AIS by regulating the formation of muscle fiber type I. [ABSTRACT FROM AUTHOR]

Satellite cells (SC) are of importance for muscular adaptation to various forms of exercise. A single bout of high-force eccentric exercise has been shown to induce SC activation and, for electrically stimulated exercise, SC differentiation. Purpose: This study aimed to assess if one bout of concentric/eccentric exercise with damaging eccentric overload (CON/ECC+) provides a sufficient stimulus to induce SC activation, proliferation, and differentiation. Methods : Biopsies from the vastus lateralis muscle of recreationally active men were obtained in the rested condition and again from the contralateral leg 7 d after exhaustive concentric/eccentric (CON/ECC) (n = 15) or CON/ECC+ (n = 15) leg extension exercise and in a nonexercising control group (CG) (n = 10). Total SC number (Pax7+), activated (Pax7+/MyoD+), and differentiating (myogenin+) SCs, fiber type distribution, and myofibers expressing neonatal myosin heavy chain (MHCneo) were determined immunohistochemically. Creatine kinase and myoglobin were measured in venous blood. Isokinetic strength tests were repeatedly conducted. Results : Significant increases in creatine kinase and myoglobin (P = 0.001) indicated myofiber damage, whereas maximal strength was not impaired. Only after CON/ECC+, SC content (P = 0.019) and SC related to type II fibers (P = 0.011) were significantly increased. A significant increase in the proportion of activated SCs occurred after CON/ECC+ only (P = 0.003), the increase being significantly (P < 0.05) different from the changes after CON/ECC and in CG. The number of differentiating SC and MHCneo remained unchanged. Conclusions : Eccentric overload during leg extension exercise induced significant SC activation, increases in SC content and in SC number related to type II myofibers. However, there were no signs of increased SC differentiation or formation of new myofibers. [ABSTRACT FROM AUTHOR]

Abstract Background Dysferlinopathies are a group of muscle disorders causing muscle weakness and absence or low levels of dysferlin, a type-II transmembrane protein and the causative gene of these dystrophies. Dysferlin is implicated in vesicle fusion, trafficking, and membrane repair. Muscle biopsy of patients with dysferlinopathy is characterized by the presence of inflammatory infiltrates. Studies in the muscle of both human and mouse models of dysferlinopathy suggest dysferlin deficient muscle plays a role in this inflammation by releasing thrombospondin-1. It has also been reported that vitamin D3 treatment enhances dysferlin expression. The ubiquitin-proteasome system recognizes and removes proteins that fail to fold or assemble properly and previous studies suggest that its inhibition could have a therapeutic effect in muscle dystrophies. Here we assessed whether inhibition of the ubiquitin proteasome system prevented degradation of dysferlin in immortalized myoblasts from a patients with two missense mutations in exon 44. Methods To assess proteasome inhibition we treated dysferlin deficient myotubes with EB1089, a vitamin D3 analog, oprozomib and ixazomib. Western blot was performed to analyze the effect of these treatments on the recovery of dysferlin and myogenin expression. TSP-1 was quantified using the enzyme-linked immunosorbent assay to analyze the effect of these drugs on its release. A membrane repair assay was designed to assess the ability of treated myotubes to recover after membrane injury and fusion index was also measured with the different treatments. Data were analyzed using a one-way ANOVA test followed by Tukey post hoc test and analysis of variance. A p ≤ 0.05 was considered statistically significant. Results Treatment with proteasome inhibitors and EB1089 resulted in a trend towards an increase in dysferlin and myogenin expression. Furthermore, EB1089 and proteasome inhibitors reduced the release of TSP-1 in myotubes. However, no effect was observed on the repair of muscle membrane after injury. Conclusions Our findings indicate that the ubiquitin-proteasome system might not be the main mechanism of mutant dysferlin degradation. However, its inhibition could help to improve muscle inflammation by reducing TSP-1 release.

Background and objectives: Osteoarthritis is one of the most common arthritic diseases and a main cause of pain and disability. Simultaneous downexpression of paired box 7 (Pax7) and myogenin genes, as indicators of satellite cells activation is evident in osteoarthritis. This study assessed effects of an exercise training course and stem cell injection on the expression of Pax7 and myogenin in gastrocnemius muscle of rats with arthritis. Methods: Thirty five male rats aged 6–8 weeks and weighing 250–300 g were divided into five groups: control, patient, exercise, mesenchymal stem cell (MSC), and exercise+MSC. Osteoarthritis was induced in rats by surgery. The training program consisted of 30 minutes of running on a non-slip treadmill at a speed of 16 m/min. The rats were injected with 1×106 cells/kg MSC. The expression of Pax7 and myogenin was measured by real–time PCR. Data were analysed with SPSS (version 23) using one-way analysis of variance. Results: Both Pax7 and myogenin were significantly overexpressed in the exercise+MSC group compared to the patient group (P

A 9-year-old female Lolo dog presented with a subcutaneous, large mass protruding from the right-side of her flank region with intact covering skin. Surgical excision of the mass revealed a well demarcated, large firm mass without invading the underlying muscle of the flank. The gross examination revealed a fish-flesh colored, large firm mass, histologically neoplastic cells exhibiting pleomorphism, multinucleated giant cells, and bizarre mitosis. Using immunohistochemical staining, the tumor cell was expressed with vimentin, desmin, and myogenin. Based on histological and immunohistochemical staining, it was confirmed as PRMS. The dog was followed up to 2 years after surgical removal. There was no recurrence, and the dog had normal health. The present case indicated that PRMS had characteristically histological and immunohistochemical features that could be used in differential diagnosis from highly confusing alveolar and embryonal rhabdomyosarcoma in dogs, and it must be included in differential diagnosis of anaplastic sarcoma in adult dogs. [ABSTRACT FROM AUTHOR]

There are weight and size differences in skeletal muscles of fast- (FG), and slow- growing (SG) chickens, however, the underlying molecular mechanisms responsible for the differences in post-hatch muscle development are unclear. Here, we report on the identification of several candidate genes that may modulate myofiber growth and thus explain some of the differences in the skeletal muscle phenotype of FG and SG chickens. We collected pectoralis major (PM) and gastrocnemius muscles (GM) on d 1, 7, 28, 49, and 70 post-hatch, and measured the weights of the muscles, diameter and, a density of myofibers, and the expression abundances of MyoD, MyoG, IGF-1, and Pax7. The body weight of FG was heavier than SG from d 7 to 70. Their muscle weights and myofiber diameters of FG were also greater than SG (P < 0.05). The expression of MyoG was affected by chicken population, age, and muscle-type. It was the heaviest in PM for FG on d 28, compared with other combinations. The expression of Pax7 mRNA paralleled changed in myofiber density, whereas the expression profiles of MyoG and MyoD were similar to the developmental changes in myofiber diameter. Overall, body weight and muscle expansion of SG chickens were less than FG chickens. MyoG was the possible gene controlling myofiber development as its expression abundances were associated with the muscle development profiles in the SG and FG chickens, respectively. [ABSTRACT FROM AUTHOR]