Myostatin Research Articles

Metabolic differences in MSTN and FGF5 dual-gene edited sheep muscle cells during myogenesis

Dynamic metabolic reprogramming occurs at different stages of myogenesis and contributes to the fate determination of skeletal muscle satellite cells (MuSCs). Accumulating evidence suggests that mutations in myostatin (MSTN) have a vital role in regulating muscle energy metabolism. Here, we explored the metabolic reprogramming in MuSCs and myotube cells in MSTN and FGF5 dual-gene edited sheep models prepared previously, and also focused on the metabolic alterations during myogenic differentiation of MuSCs. Our study revealed that the pathways of nucleotide metabolism, pantothenate and CoA biosynthesis were weakened, while the unsaturated fatty acids biosynthesis were strengthened during myogenic differentiation of sheep MuSCs. The MSTN and FGF5 dual-gene editing mainly inhibited nucleotide metabolism and biosynthesis of unsaturated fatty acids in sheep MuSCs, reduced the number of lipid droplets in per satellite cell, and promoted the pentose phosphate pathway, and the interconversion of pentose and glucuronate. The MSTN and FGF5 dual-gene editing also resulted in the inhibition of nucleotide metabolism and TCA cycle pathway in differentiated myotube cells. The differential metabolites we identified can be characterized as biomarkers of different cellular states, and providing a new reference for MSTN and FGF5 dual-gene editing in regulation of muscle development. It may also provide a reference for the development of muscle regeneration drugs targeting biomarkers.

Myostatin regulates energy homeostasis through autocrine- and paracrine-mediated microenvironment communication.

Myostatin (MSTN) has long been recognized as a critical regulator of muscle mass. Recently, there has been increasing interest in its role in metabolism. In our study, we specifically knocked out MSTN in brown adipose tissue (BAT) from mice (MSTNΔUCP1) and found that the mice gained more weight than did controls when fed a high-fat diet, with progressive hepatosteatosis and impaired skeletal muscle activity. RNA-Seq analysis indicated signatures of mitochondrial dysfunction and inflammation in the MSTN-ablated BAT. Further studies demonstrated that Kruppel-like factor 4 (KLF4) was responsible for the metabolic phenotypes observed, whereas fibroblast growth factor 21 (FGF21) contributed to the microenvironment communication between adipocytes and macrophages induced by the loss of MSTN. Moreover, the MSTN/SMAD2/3-p38 signaling pathway mediated the expression of KLF4 and FGF21 in adipocytes. In summary, our findings suggest that brown adipocyte-derived MSTN regulated BAT thermogenesis via autocrine and paracrine effects on adipocytes or macrophages, ultimately regulating systemic energy homeostasis.

Research Note: Sexual dimorphic effect of myostatin mutation on fat accumulation in Japanese quail

As an anti-myogenic factor, the myostatin (MSTN) gene was mainly considered as a genetic marker to improve meat production. Moreover, an additional effect of the MSTN mutation on reducing fat deposition in various farm animals suggested a potential application of the MSTN gene on regulating fat deposition in poultry species. Although increase in muscle mass resulted from muscle hyperplasia in the MSTN mutant quail, cellular mechanism behind the decrease in fat deposition was not investigated in the quail model. In the current study, to investigate sexual dimorphic association between fat deposition and Mstn mutation in quail, leg and abdominal fat pads from 4-month-old male and female quail were histologically analyzed. Interestingly, abdominal and leg fat pad weights were significantly decreased by the MSTN mutation only in female quail, but not in male quail, showing sexual dimorphism in regulating fat deposition by the MSTN mutation in quail. Histological analysis also revealed that fat cell sizes of leg and abdominal fats were significantly reduced only in female groups aligning with the decreased fat pad weights. Sexual dimorphic effect of the MSTN mutation on fat cell hypotrophy and reduced fat pad weights in quail provided an important scientific finding to be considered on the usage of the MSTN gene as a genetic marker to reduce fat deposition in poultry species.

Establishment of a myostatin gene-knockout C2C12 cell line and evaluation of related microRNA expression

The strategy of blocking myostatin (MSTN) signal transduction has long been regarded as a promising approach in the treatment of patients with muscle loss. However, individuals taking blocking agents often encounter issues such as lack of strength, fatigue, and poor muscle proliferation due to muscle hypertrophy and the involvement of multiple receptors. To address these challenges, a series of experiments were conducted on a C2C12 cell line in this study. First, the pX601-SaCas9-sgRNA/puro vector carrying a Cas9-encoded gene was constructed and subsequently used to produce Mstn-knockout (Mstn-KO) C2C12 cell lines. The expression level of the MSTN protein and the growth characteristics of the cell lines were verified. Moreover, the expression of muscle growth-related microRNAs in the cell lines was analyzed through real-time polymerase chain reaction (PCR). The results indicate that we have successfully established a method for constructing Mstn-KO cell lines with stable passage. No expression of the MSTN protein and strong cell proliferation were observed in the cell lines. Moreover, real-time PCR experiments showed that the expression levels of miR-1, miR-431, miR-206, and miR-133a were significantly increased (P < 0.01), the expression level of miR-23a was significantly increased (P < 0.05), and the expression level of miR-486 was significantly decreased (P < 0.05). These findings indicate that multiple miRNAs are closely associated with MSTN regulation. This study lays the foundation for further investigation into the effects of the Mstn gene on the physiological function of myoblasts and the development of drugs that block the MSTN signaling pathway.

Nutritional synergy: optimizing growth in Siruvidai chicken via diverse dietary energy and protein strategies and gene expression analysis - brooder phase.

Nutrient supply regulates overall body growth directly or indirectly through its influence on regulatory factors optimizing nutrient requirements becomes crucial before embarking on genetic improvements. Hence this study addresses this gap by evaluating the effect of feeding varying energy and crude protein levels on growth performance and gene expression related to the growth of indigenous Siruvidai chicken from 0 to 12 weeks. A 360-day-old straight-run Siruvidai chick were randomly distributed into six experimental groups with three replicates of each 20 chicks. The birds were fed corn-soy-based diets formulated with two levels of energy (2500 and 2700kcal ME/kg) each with three levels of crude protein (16, 18, and 20%) during the brooder stage (0-12 weeks) in 2 × 3 factorial design. Results revealed that there was no significant effect on the energy and protein interaction levels on average feed intake, body weight gain and feed conversion ratio in Siruvidai chicken at 12 weeks. The results showed significantly (P < 0.05) lower feed intake in 18% protein fed groups and significantly (P < 0.01) lower feed intake in higher energy 2700kcal ME/kg fed groups. A better feed conversion ratio (4.06 and 4.21) was observed on the effect of protein levels in bird diets with 18% and 20% protein fed groups. The Growth Hormone (GH) and Myostatin (MSTN) gene expression were significantly (P < 0.01) higher in 16% CP and 2500kcal ME/kg in hepatic tissue. The high protein and low energy diet up-regulated the Insulin-like Growth Factor-1 (IGF-1) gene expression in hepatic tissue. The study concluded that Siruvidai chicken fed with 18% crude protein and 2500kcal ME/kg is optimum for 0-12 weeks of age.

Circulating myostatin as a biomarker of muscle mass and strength in individuals with cancer or obesity

Background & AimsOur study aims to determine whether myostatin (MSTN) is associated with muscle mass and strength in individuals with cancer or obesity, as well as with cancer cachexia (CC) or sarcopenic obesity (SO). MethodsThe ACTICA study included individuals with CC (n=70) or without CC (NC, n=73). The MYDIASECRET study included individuals with obesity evaluated before (T0) and 3 months (T3) after bariatric surgery (n=62). Body composition was assessed using bioelectrical impedance analysis (BIA). Skeletal muscle mass (SMM) and appendicular SMM (ASMM) were calculated from Janssen’s and Sergi’s equations, respectively, and expressed as indexes (SMMI and ASMMI). Handgrip strength (HGS) was assessed using a Jamar hand-held dynamometer. MSTN plasma levels were measured using ELISA. Spearman’s coefficient was used to correlate MSTN with muscle mass and strength. Receiver operating characteristic (ROC) curve analysis was performed to identify an optimal MSTN cutoff level for the prediction of CC or SO. ResultsIn the ACTICA study, muscle mass and strength were lower in CC individuals than in NC individuals (SMMI: 8.0 kg/m2vs 9.0 kg/m2, p=0.004; ASMMI: 6.2 kg/m2vs 7.2 kg/m2, p<0.001; HGS: 28 kg vs 38 kg, p<0.001). MSTN was also lower in CC individuals than in NC individuals (1434 pg/mL vs 2149 pg/mL, p<0.001). Muscle mass and strength were positively correlated with MSTN (SMMI: R=0.500, p<0.001; ASMMI: R=0.479, p<0.001; HGS: R=0.495, p<0.001). ROC curve analysis showed a MSTN cutoff level of 1548 pg/mL (AUC 0.684, sensitivity 57%, specificity 75%, p<0.001) for the prediction of CC. In the MYDIASECRET study, muscle mass and strength were reduced at T3 (SMMI: -8%, p<0.001; ASMMI: -12%, p<0.001; HGS: -6%, p=0.005). MSTN was also reduced at T3 (1773 pg/mL vs 2582 pg/mL, p<0.001). Muscle mass and strength were positively correlated with MSTN at T0 and T3 (SMMI-T0: R=0.388, p=0.002; SMMI-T3: R=0.435, p<0.001; HGS-T0: R=0.337, p=0.007; HGS-T3: R=0.313, p=0.013). ROC curve analysis showed a MSTN cutoff level of 4225 pg/mL (AUC 0.835, sensitivity 98%, specificity 100%, p=0.014) for the prediction of SO at T3. ConclusionsMSTN is positively correlated with muscle mass and strength in individuals with cancer or obesity, suggesting its potential use as a biomarker of muscle mass and strength. The ROC curve analysis suggests the potential use of MSTN as a screening tool for CC and SO.

Alterations in the fillet quality of myostatin-knockout red sea bream Pagrus major: Preliminary insights into nutritional, compositional, and textural properties

Myostatin (MSTN) is a negative regulator of skeletal muscle growth and a popular target for enhancing the productivity of farmed fish. We previously developed an mstn-knockout breed of the aquaculture fish red sea bream (Pagrus major) using genome editing technology. However, little is known about the effects of mstn disruption on the fillet quality of red sea bream and other fish species. In this study, we used fillets of mstn-deficient red sea bream to evaluate their compositional and textural changes during refrigeration. Compared to the wild type, the mutant fillets exhibited an increase in moisture content and a decrease in drippings, indicating an enhanced water-holding capacity. Furthermore, the mutant fillets showed increased water retention and marginally lower collagen content, resulting in lower breaking force, an index of texture. In conclusion, we demonstrated that mstn disruption alters the compositional and textural properties of red sea bream fillets.

Inactivation of Myostatin Delays Senescence via TREX1-SASP in Bovine Skeletal Muscle Cells.

The myostatin (MSTN) gene also regulates the developmental balance of skeletal muscle after birth, and has long been linked to age-related muscle wasting. Many rodent studies have shown a correlation between MSTN and age-related diseases. It is unclear how MSTN and age-associated muscle loss in other animals are related. In this study, we utilized MSTN gene-edited bovine skeletal muscle cells to investigate the mechanisms relating to MSTN and muscle cell senescence. The expression of MSTN was higher in older individuals than in younger individuals. We obtained consecutively passaged senescent cells and performed senescence index assays and transcriptome sequencing. We found that senescence hallmarks and the senescence-associated secretory phenotype (SASP) were decreased in long-term-cultured myostatin inactivated (MT-KO) bovine skeletal muscle cells (bSMCs). Using cell signaling profiling, MSTN was shown to regulate the SASP, predominantly through the cycle GMP-AMP synthase-stimulator of antiviral genes (cGAS-STING) pathway. An in-depth investigation by chromatin immunoprecipitation (ChIP) analysis revealed that MSTN influenced three prime repair exonuclease 1 (TREX1) expression through the SMAD2/3 complex. The downregulation of MSTN contributed to the activation of the MSTN-SMAD2/3-TREX1 signaling axis, influencing the secretion of SASP, and consequently delaying the senescence of bSMCs. This study provided valuable new insight into the role of MSTN in cell senescence in large animals.

The Association of Myostatin on the Expression of Inflammatory Cytokines and Chemokines in Rheumatoid Arthritis Synovial Fibroblasts

Rheumatoid arthritis (RA) is a chronic autoimmune disease initiated and progressed by RA synovial fibroblast cells (RASFs) of the synovium. Inflammatory cytokines/chemokines play a crucial role in disease development. Myostatin (MSTN) is widely comprehended as a significant regulator of pro-inflammatory cytokines/chemokines in many other autoimmune diseases. However, its role during the progression of RA is still unclear. We hypothesized that MSTN regulates the inflammatory cytokines/chemokines expression in RASFs. The immortalized RASF cells (MH7A) were treated with MSTN or MSTN inhibitor (0, 10, and 20 ng/mL) for 0, 24, and 48 h. Then, the secretion and expression of inflammatory cytokines (IL-8, IL-17, TNF-α, IL-6, IL-23, IFN-γ, IFN-β) and chemokines (CCL-2, CCL-20, CXCL-13, CXCL-1) were measured by enzyme-linked immunosorbent assay (ELISA) and reverse transcription-quantitative polymerase chain reaction (RT-qPCR). Furthermore, MH7A cells were treated with 20 ng/mL of TNF-α, IL-17, IFN-γ IFN-β, CCL-2, and CXCL-1 for 24 h to examine their effects on MSTN expression and secretion. Data were analyzed by Kruskal-Wallis rank sum test, followed by Dunn’s multiple comparison test. The MSTN expression and secretion were measured by RT-qPCR, ELISA, and Western blot. Results showed that 20 ng/mL MSTN treatment significantly (p&lt;0.05) increased the secretion of most inflammatory cytokines/chemokines at 24 or 48 h. CXCL-1 showed the highest secretion (30-fold in average) in response to MSTN treatment, followed by CCL-2 (13-fold in average) at 24 h and IL-23 (3-fold in average) at 48 h. Similar to ELISA results, MSTN significantly upregulated the mRNA expression of most inflammatory cytokines/chemokines at 24 or 48 h. The highest expression was TNF-α (60-fold in average) at 48 h, followed by CXCL-1 (15-fold in average) and CCL-2 (13-fold in average) at 24 h. The effect of MSTN inhibitor on cytokines/chemokines secretion and mRNA expression was inconsistent. Among the six cytokines/chemokines used to investigate their effects on MSTN expression in MH7A cells, IFN-γ significantly increased MSTN secretion (13-fold in average) and mRNA expression (100-fold in average) but other cytokine/chemokines showed no significant response. Western blot results showed that MSTN secretion was significantly increased by IFN-γ treatment, supporting the ELISA results. Current results demonstrated that MSTN upregulated the mRNA expression and secretion of various inflammatory cytokines/chemokines and IFN-γ significantly increased MSTN expression and secretion, indicating a cross-stimulation between MSTN and inflammatory cytokines/chemokines in RA. This study was funded by NIH 5R01AR043521-29. This is the full abstract presented at the American Physiology Summit 2024 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.

Association Between Muscle Growth and Transcription of a Mutant MSTN Gene in Olive Flounder (Paralichthys olivaceus).

Myostatin (MSTN, also known as growth differentiation factor-8 (GDF-8)), a member of the transforming growth factor β (TGF-β) superfamily, functions as a negative regulator of skeletal muscle development and growth. However, it is also expressed in a wide range of tissues in fish and thus may have more diverse roles in this group than in mammals. In this study, we assessed the genome-wide transcriptional expression pattern associated with the CRISPR/Cas9-mutated MSTN gene in the olive flounder (Paralichthys olivaceus) in association with changes in cell proliferation and transportation processes. There were no differences in the hepatosomatic index, and the growth of male and female fish increased in the F1 progeny of the MSTN mutants. Furthermore, the histopathological analysis showed that myostatin editing resulted in a 41.24% increase in back muscle growth and 46.92% increase in belly muscle growth in male flounder compared with normal flounder, and a 16.01% increase in back muscle growth and 14.26% increase in belly muscle growth in female flounder compared with normal flounder. This study demonstrates that editing of the myostatin gene enhances muscle growth in olive flounder, with a notably more pronounced effect observed in males. Consequently, myostatin-edited male flounder could represent a valuable asset for the flounder aquaculture industry.

Assessing the performance of Moghani crossbred lambs derived from different mating systems with Texel and Booroola sheep.

In our ongoing project, which focuses on the introgression of Booroola/FecB gene and the myostatin (MSTN) gene into purebred Moghani sheep, we assessed the performance of second-generation Moghani crossbreds such as second crossbreds (F2) and initial backcross generation (BC1). These crossbreds were generated through different mating systems, including in-breeding, outcrossing, first paternal backcrossing (PBC1), and first maternal backcrossing (MBC1). Notably, F2 strains exhibited lean tail, woolly fleece and a higher percentage of white coat color compared to BC1. The impact of mating systems and birth types on pre-weaning survival rates was found to be statistically significant (P < 0.0001), with singleton offspring resulting from paternal backcross showing a particularly substantial effect. The F2 crossbred lambs carrying the Booroola gene did not show a statistically significant difference in survivability compared to those carrying the MSTN gene, implying the Booroola prolificacy gene had no significant impact on survival outcomes. However, the occurrence of multiple births had a significant negative impact on lamb survival (P < 0.0001). The PBC1 sheep strains, specifically Texel Tamlet ram strains carrying the MSTN mutation, exhibited superior growth rates compared to others (P < 0.05). Interestingly, the MSTN mutation in the homozygous variant genotype significantly impacts growth rate before weaning compared to other genotypes and pure Moghani sheep (P < 0.05). In conclusion, this study objectively underscores the pivotal role of genetic factors, specifically through strategic mating systems like paternal backcrossing, in enhancing desired traits and growth rates in Moghani sheep, thereby contributing valuable insights to the field of sheep breeding programs.

Myostatin promotes proliferation of bovine muscle satellite cells through activating TRPC4/Ca2+/Calcineurin/NFATc3 pathway

Myostatin (MSTN) is principally expressed in skeletal muscle and negatively regulates muscle growth and development. MSTN mutation can induce muscle overgrowth in cattle by activating cell proliferation, presenting a “double-muscle” phenotype. However, the specific regulatory mechanism is still unclear. Here, we found that Ca2+ content in muscle tissue and muscle satellite cells of MSTN mutated (MSTN-/-) cattle were significantly increased compared to wild-type (WT). Furthermore, transcriptome analysis of muscle satellite cells revealed that TRPC4 was significantly increased in MSTN-/- cattle. And the expression of TRPC4 in muscle tissue of MSTN-/- cattle was detected by RT-qPCR and Western blot, which was significantly higher than that of WT. These results suggested that MSTN mutation promoted muscle satellite cells proliferation through activation of TRPC4 channel. To further verify, ML204, a specific inhibitor of TRPC4, was used to treat MSTN-/- muscle satellite cells. We found that cell proliferation was inhibited, Calcineurin expression was downregulated, and the entry of NFATc3 into nuclei was reduced, which was similar to WT group. Thus, MSTN mutation leads to the activation of TRPC4 channel, which increases intracellular Ca2+ content, further activates Calcineurin/NFATc3 pathway, and ultimately promotes the proliferation of muscle satellite cells.

Significance of dietary quinoa husk (Chenopodium quinoa) in gene regulation for stress mitigation in fish

The persistent challenges posed by pollution and climate change are significant factors disrupting ecosystems, particularly aquatic environments. Numerous contaminants found in aquatic systems, such as ammonia and metal toxicity, play a crucial role in adversely affecting aquaculture production. Against this backdrop, fish feed was developed using quinoa husk (the byproduct of quinoa) as a substitute for fish meal. Six isonitrogenous diets (30%) and isocaloric diets were formulated by replacing fish meal with quinoa husk at varying percentages: 0% quinoa (control), 15, 20, 25, 30 and 35%. An experiment was conducted to explore the potential of quinoa husk in replacing fish meal and assess its ability to mitigate ammonia and arsenic toxicity as well as high-temperature stress in Pangasianodon hypophthalmus. The formulated feed was also examined for gene regulation related to antioxidative status, immunity, stress proteins, growth regulation, and stress markers. The gene regulation of sod, cat, and gpx in the liver was notably upregulated under concurrent exposure to ammonia, arsenic, and high-temperature (NH3 + As + T) stress. However, quinoa husk at 25% downregulated sod, cat, and gpx expression compared to the control group. Furthermore, genes associated with stress proteins HSP70 and DNA damage-inducible protein (DDIP) were significantly upregulated in response to stressors (NH3 + As + T), but quinoa husk at 25% considerably downregulated HSP70 and DDIP to mitigate the impact of stressors. Growth-responsive genes such as myostatin (MYST) and somatostatin (SMT) were remarkably downregulated, whereas growth hormone receptor (GHR1 and GHRβ), insulin-like growth factors (IGF1X, IGF2X), and growth hormone gene were significantly upregulated with quinoa husk at 25%. The gene expression of apoptosis (Caspase 3a and Caspase 3b) and nitric oxide synthase (iNOS) were also noticeably downregulated with quinoa husk (25%) reared under stressful conditions. Immune-related gene expression, including immunoglobulin (Ig), toll-like receptor (TLR), tumor necrosis factor (TNFα), and interleukin (IL), strengthened fish immunity with quinoa husk feed. The results revealed that replacing 25% of fish meal with quinoa husk could improve the gene regulation of P. hypophthalmus involved in mitigating ammonia, arsenic, and high-temperature stress in fish.

Genetic Association of MSTN Gene Variant (18:66493737T&gt;C) with Track Performance &amp; Muscle Development in Pakistani Horses

The horse, revered for its diverse traits including racing prowess, gaitedness, and distinctive behavior, plays a pivotal role in various sports. Numerous studies have linked racing performance in horses to the MSTN gene across global populations. Objectives: To investigate the genetic variability of the 18:66493737T&gt;C variant in Pakistani random-bred horses. Methods: ARMS-PCR was employed where 24 horses sourced from UVAS equine clinic were genotyped. Results: Revealing a population distribution of 54% homozygous wild-type (TT), 41% heterozygous (TC), and 4% homozygous mutant (CC) at this locus. The alternative allele frequency within elite performers and control horses stood at 0.36 and 0.12, respectively. Application of the Chi-Square association test using the PLINK data toolset yielded a highly significant p-value of 7.832×10-6. Conclusions: This underscores significant genetic variability at the locus in the Pakistani horse population, aligning with global patterns. Future studies are advocated, incorporating racing performance data and encompassing diverse indigenous horse breeds with substantial sample sizes. Identification of subject markers can inform targeted breeding strategies, contributing to the enhancement and preservation of desirable traits across various horse breeds

Production performance analysis of sheep MSTN gene C2361T locus

The myostatin (MSTN) gene exhibits significant nucleotide sequence variations in sheep, impacting growth characteristics and muscular traits of the body. However, its influence on specific growth traits in some sheep remains to be further elucidated. This study utilized single nucleotide polymorphism sequence analysis to investigate the role of the MSTN gene in meat production performance across four sheep breeds: Charolais sheep, Australian White sheep, crossbreeds of Australian White and Small-tailed Han, and crossbreeds of Charolais and Small-tailed Han. At a SNP locus of the MSTN gene, the C2361T site was identified, with three genotypes detected: CC, CT, and TT, among which CC predominated. Gene substitution effect analysis revealed that replacing C with T could elevate the phenotypic value. Comparative analysis of data from different genotypes within the same breed highlighted the superiority of CC and TT genotypes in phenotypic values, underscoring the significance of specific genotypes in influencing key traits. Contrasting the performance of different genotypes across breeds, Charolais sheep and Charolais Han hybrids demonstrated superiority across multiple indicators, offering valuable insights for breeding new sheep varieties. Analysis of gender effects on growth characteristics indicated that ewes exhibited significantly wider chest, waist, and hip widths compared to rams, while rams displayed better skeletal growth and muscle development. Additionally, the MSTN gene also exerted certain effects on lamb growth characteristics, with the CC genotype closely associated with weight. These findings not only contribute crucial insights for sheep breeding but also pave the way for future research exploring the interaction of this gene with others.

Abstract 771: A TGF-β superfamily member, myostatin contributes to MASH and HCC via muscle atrophy by disrupting TGF-β signaling, and is a potential marker with PKM2 for human HCC

Abstract Background: In patients with cirrhosis and hepatocellular carcinoma (HCC), sarcopenia or skeletal muscle loss, as well as metabolic alterations are frequent and progressive comorbidities. Myostatin, a TGF-β superfamily member is expressed primarily in skeletal muscle, inhibits muscle growth, and causes sarcopenia in cirrhosis. Previously, we had observed liver-specific knockout of the SMAD3 adaptor, βII-spectrin -Sptbn1 (βS-LSKO) or siRNA targeting βII-spectrin blocks sarcopenia, fatty liver disease-MASH and HCC (Sci TM 2021), suggesting that βII-spectrin may be a viable strategy to identify mechanisms, as well as new biomarkers of MASH and HCC. Methods: 1. SPTBN1Flox (control) and liver-specific βII-spectrin knockout (SPTBN1LSKO) mice were fed Western diet (WD) and treated with Diethylnitrosamine (DEN) for obesity-associated HCC. Muscle mass, body weight and multiple enzymes involved in glycolysis as well as sarcopenia were measured in mutant mice. 2. In tumors, a rate-limiting enzyme in glycolysis, pyruvate kinase isozyme M2 (PKM2) that mediates inflammation and aerobic glycolysis in Warburg effect. Therefore, we further examined TGF-β pathway-enriched biomarkers such as Myostatin and PKM2 for markers of HCC and whether these could stratify risk in patients with cirrhosis for HCC, in a four-institution cohort, (n=157) compared to cirrhosis patients (n=380). Results: 1. Like human fatty liver disease, obese mutant mice show marked sarcopenia with increased PKM2 and Myostatin levels with decreased p-RPS6/total-RPS6 ratio (indicating mTOR signaling inhibition) in striated muscle tissue. In contrast, levels are restored to normal in the liver specific knockout of SPTBN1. 2. Using the 108 markers as well as PKM2 and myostatin (MSTN), we found 31 markers with false discovery rate (FDR) p values &amp;lt; 0.10 from univariable Kruskal-Wallis tests for the associations of markers with HCC vs. cirrhosis. Conclusions: Our results reveal that SMAD3 adaptor, βII-spectrin liver-specific knockout decreases Myostatin and PKM2 expression, providing new insight into molecular mechanisms in MASH and HCC. These studies reflect that these are biologically functional circuits that could provide new serum markers, such as Myostatin and PKM2 for risk stratification of HCC. Citation Format: Kazufumi Ohshiro, Krishanu Bhowmick, Xiyan Xiang, Shivani Kapoor, Richard Amdur, Srinivasan Dasarathy, Adrian R. Krainer, Lopa Mishra. A TGF-β superfamily member, myostatin contributes to MASH and HCC via muscle atrophy by disrupting TGF-β signaling, and is a potential marker with PKM2 for human HCC [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2024; Part 1 (Regular Abstracts); 2024 Apr 5-10; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2024;84(6_Suppl):Abstract nr 771.

Anabolic myokine responses and muscular performance following 8 weeks of autoregulated compared to linear resistance exercise in recreationally active males.

To date, no studies, to our knowledge, have compared the efficacy of autoregulated periodized and linear resistance exercises on anabolic myokines and muscular performance among recreationally active individuals. This study aimed to compare the effects of an 8-week autoregulated periodized resistance exercise (APRE) program with a linear resistance exercise (LRE) program on insulin-like growth factor-1 (IGF-1), follistatin (FST), myostatin (MST), body composition, muscular strength, and power in recreationally active males. Thirty males were randomly assigned to either the APRE group (n = 15) or the LRE group (n = 15). Participants completed training three times a week for 8 weeks. The outcome measures included serum IGF-1, FST, MST, muscular strength (isometric knee extension and handgrip), power (vertical jump), lean body mass, and fat mass. IGF-1 circulating levels increased over time following APRE (34%) and with no significant change following LRE (~-1%). There were no significant differences over time or between groups for FST or MST. Muscular strength (knee extension [21.5 vs. ~16%] and handgrip [right: 31 vs. 25%; left: 31.7 vs. 28.8%]) and power (~ 33 vs. ~26%) significantly increased to a greater extent following APRE compared to LRE. Interestingly, the results revealed that lean body mass increased over time only after APRE (~ 3%), but not LRE. These findings suggest that APRE may be more effective than LRE in increasing muscular strength, power, and lean body mass, as well as circulating IGF-1 levels, in recreationally active males. The observed differences may be attributed to the increased training volume associated with APRE. However, further research is needed to directly assess muscle protein synthesis.

Myostatin and Activin A as Biomarkers of Sarcopenia in Inflammatory Bowel Disease Patients.

The prevalence of sarcopenia in inflammatory bowel disease patients has received increasing attention. The aim of this study is to assess the usefulness of determining levels of myostatin (MSTN) and activin A (Act A) as potential markers of disease activity and occurrence of sarcopenia in Crohn's disease and ulcerative colitis patients. The case-control study included 82 patients with Inflammatory Bowel Disease. The control group consisted of 25 healthy volunteers. The serum levels of myostatin and activin A were determined by the quantitative sandwich enzyme-linked immunosorbent assay. Sarcopenia was diagnosed based on the EWGSOP2 criteria. The study found lower levels of myostatin and activin A in the IBD patients. There were significantly lower levels of myostatin (80.6 pg/mL vs. 186.2 pg/mL; p = 0.0364) as well as activin A (32.1 pg/mL vs. 35.2 pg/mL; p = 0.0132) in the IBD patients with sarcopenia compared to those without sarcopenia. Positive correlations were found between MSTN levels and Muscle Mass Index (rho = 0.31; p < 0.005) and hand grip strength (rho = 0.34, p < 0.05) in the IBD patients. The determination of serum levels of MSTN and Act A may be useful in the early diagnosis of sarcopenia in IBD patients.

Equine Asthma Does Not Affect Circulating Myostatin Concentrations in Horses.

(1) Background: The number of horses suffering from chronic respiratory diseases, resembling human asthma, is increasing but there is still a lack of reliable and accurate methods to detect these disorders. Numerous studies have found elevated plasma concentrations of one of the myokines, namely, myostatin (MSTN), in people suffering from severe asthma. MSTN normally inhibits myoblast proliferation and differentiation through autocrine or paracrine signals. Therefore, given the pathogenesis of asthma, we hypothesize that MSTN could be a useful biomarker of equine asthma. Thus, this study aimed to compare the concentration of MSTN in the blood plasma of fully healthy and asthmatic horses. (2) Methods: A total of 61 horses were clinically examined to confirm or exclude the occurrence of equine asthma, including bronchoalveolar lavage (BAL) fluid cytology performed on 49 horses. This study included three groups of horses, two of which were clinically healthy, and one of which was asthmatic. (3) Results: The mean circulatory MSTN concentration determined using the ELISA method in asthmatic horses was significantly higher than that in clinically healthy young Thoroughbred racehorses (p < 0.05), but it did not differ as compared to the group of healthy, adult leisure horses. (4) Conclusions: The obtained results did not unambiguously support our original hypothesis that MSTM may be a reliable marker for the early diagnosis of equine asthma. To the best of the authors' knowledge, this is the first study to analyze the plasma MSTN concentration in equine asthma patients, and therefore further studies are needed to confirm our novel findings.

Myokines: metabolic regulation in obesity and type 2 diabetes

Abstract Skeletal muscle plays a vital role in the regulation of systemic metabolism, partly through its secretion of endocrine factors which are collectively known as myokines. Altered myokine levels are associated with metabolic diseases, such as type 2 diabetes (T2D). The significance of interorgan crosstalk, particularly through myokines, has emerged as a fundamental aspect of nutrient and energy homeostasis. However, a comprehensive understanding of myokine biology in the setting of obesity and T2D remains a major challenge. In this review, we discuss the regulation and biological functions of key myokines that have been extensively studied during the past two decades, namely interleukin 6 (IL-6), irisin, myostatin (MSTN), growth differentiation factor 11 (GDF11), fibroblast growth factor 21 (FGF21), apelin, brain-derived neurotrophic factor (BDNF), meteorin-like (Metrnl), secreted protein acidic and rich in cysteine (SPARC), β-aminoisobutyric acid (BAIBA), Musclin, and Dickkopf 3 (Dkk3). Related to these, we detail the role of exercise in myokine expression and secretion together with their contributions to metabolic physiology and disease. Despite significant advancements in myokine research, many myokines remain challenging to measure accurately and investigate thoroughly. Hence, new research techniques and detection methods should be developed and rigorously tested. Therefore, developing a comprehensive perspective on myokine biology is crucial, as this will likely offer new insights into the pathophysiological mechanisms underlying obesity and T2D and may reveal novel targets for therapeutic interventions.