Chao Hai

The gut–muscle axis plays a vital role in host metabolism and health. Although the MSTN gene is a well-known negative regulator of muscle growth, its role in intestinal function and metabolism remains unclear. Understanding this connection is crucial for revealing the systemic impact of MSTN gene editing and its potential to improve metabolic efficiency in livestock. In this study, we investigated the influence of MSTN deletion on gut microbiota composition and carbohydrate metabolism in the cecum and colon of cattle. Using integrated metagenomic, metabolomic, serum biochemical, and muscle transcriptomic analyses, we found significant alterations in microbial communities and key metabolic pathways. Hallella and Escherichia in the colon, as well as Alishewanella in the cecum, were closely linked to carbohydrate metabolism. Differential microbes and metabolites influenced key metabolic pathways, including glycolysis/gluconeogenesis and lipopolysaccharide biosynthesis. Functional gene analysis identified Bacteroides as the most critical bacterium affecting glycolysis/gluconeogenesis. Additionally, genes related to carbohydrate esterases were upregulated. These changes correlated with reduced serum glucose and insulin levels while increasing muscle gene expression related to glucose-to-lactose conversion. Overall, MSTN gene editing alters gut microbiota composition and carbohydrate metabolism in the cecum and colon, thereby influencing host glucose metabolism and energy homeostasis.

Myostatin (MSTN) is a critical regulator of muscle development. This study aimed to investigate the transcriptional and epigenetic mechanisms by which MSTN gene editing affects skeletal, cardiac, and smooth muscle function in cattle. The results showed that the MSTN gene-edited (MT) cattle skeletal muscle exhibited significantly larger myofiber cross-sectional areas (p = 0.049), accompanied by reduced shear force (p = 0.044), cooking loss rate (p = 0.0029), and pH (p = 0.014). Transcriptomic and whole-genome bisulfite sequencing (WGBS) revealed distinct expression and methylation patterns across muscle types. Notably, axon guidance signaling was identified as a shared enriched pathway in both transcriptional and CG/CHG/CHH methylation profiles of the gluteus. Further, 102 differentially expressed genes (DEGs) were commonly identified across all three muscle types; their KEGG enrichment included immune-related and cellular interaction pathways (e.g., antigen processing and presentation, and cell adhesion molecules), many of which intersect with axon guidance functions. Core regulators such as SEMA3A, PLXNA1, and NTN1 were epigenetically modulated in MT gluteus and heart. These findings suggest that MSTN knockout remodels neuromuscular signaling through muscle-type-specific transcriptional and epigenetic reprogramming.

Desert environments pose severe challenges to livestock survival. This study examined climate-driven physiological and metabolic adaptations in 258 Mongolian cattle from six regions of the Alxa Desert, China. Serum biochemical indices were measured and analyzed using linear models to assess the effects of climate, sex, and age. Climate significantly affected key blood parameters, including glucose (p < 0.001), creatinine (p < 0.001), alkaline phosphatase (p < 0.001), and lactate (p = 0.034). Additionally, sex significantly influenced lactate dehydrogenase (p = 0.049), bicarbonate (p = 0.0061), urea (p = 0.0055), and triglycerides (p = 0.039), while age affected total protein (p = 0.020), LDL-C (p = 0.0097), and cholesterol (p < 0.001). Glucose levels were negatively correlated with body size traits. Metabolomic profiling showed that cattle in arid, high-radiation areas exhibited reduced TCA cycle and fatty acid metabolism, with concurrent carbohydrate accumulation, including glucose, fructose, and mannose. Enhanced amino acid metabolism increased proline, valine, tyrosine, and tryptophan levels, potentially supporting physiological stability under heat and drought stress. These findings reveal how Mongolian cattle modulate metabolism in response to desert climates, offering insights into livestock adaptation and informing breeding strategies for resilience in harsh environments.

N6-methyladenosine (m6A) modification is a key methylation modification involved in reproductive processes. Myostatin gene editing (MT) in cattle is known to enhance muscle mass and productivity. However, the changes in m6A modification in MT bull sperm remain poorly understood. In the MT and wild-type (WT) groups, we identified 25,542 and 22,253 m6A peaks, respectively, mainly concentrated in the coding sequence (CDS) and 3′ untranslated region (UTR) of genes. The MT group showed an increase in gene transcription, but there was no significant difference in the overall m6A peaks pattern. There was also no significant difference in m6A motif and chromosome distribution between MT and WT groups. Most genes had less m6A modification sites. A total of 1120 m6A peaks were significantly different, corresponding to 1053 differentially m6A-methylated genes (DMMGs). These DMMGs are mainly associated with G protein-coupled receptor signaling pathways and the overall composition of the cell membrane. Furthermore, an MCL clustering analysis of 111 differentially m6A-methylated and expressed genes identified seven key genes (RHOA, DAAM1, EXOC4, GNA12, PRICKLE1, SCN1A, and STXBP5L), with the cytoskeleton and migration-related gene, RHOA, being the most important gene located at the center of the gene network. However, the analysis of sperm morphology and motility indicated no significant changes in semen volume, sperm count, sperm viability, plasma membrane integrity, acrosome membrane integrity, or mitochondrial membrane integrity. This study provides a map of m6A methylation in spermatozoa from MT and WT bulls, identifies key differential m6A genes that are affected by the myostatin gene but do not affect sperm morphology and viability in MT bulls, and provides a theoretical basis for the breeding quality of MT bulls.

(1) Background: Myostatin (MSTN) is a protein that regulates skeletal muscle development and plays a crucial role in maintaining animal body composition and muscle structure. The loss-of-function mutation of MSTN gene can induce the muscle hypertrophic phenotype. (2) Methods: Growth indexes and blood parameters of the cattle of different months were analyzed via multiple linear regression. (3) Results: Compared with the control group, the body shape parameters of F2 cattle were improved, especially the body weight, cross height, and hip height, representing significant development of hindquarters, and the coat color of the F2 generation returned to the yellow of Luxi cattle. As adults, MSTN gene-edited bulls have a tall, wide acromion and a deep, wide chest. Both the forequarters and hindquarters are double-muscled with clear muscle masses. The multiple linear regression demonstrates that MSTN gene-edited hybrid beef cattle gained weight due to the higher height of the hindquarters. Significant differences in blood glucose, calcium, and low-density lipoprotein. Serum insulin levels decreased significantly at 24 months of age. MSTN gene editing improves the adaptability of cattle. (4) Conclusions: Our findings suggest that breeding with MSTN gene-edited Luxi bulls can improve the growth and performance of hybrid cattle, with potential benefits for both farmers and consumers.

Myostatin (MSTN) is a negative regulator of skeletal muscle genesis during development. MSTN mutation leads to increased lean meat production and reduced fat deposition in livestock. However, the mechanism by which MSTN promotes myogenesis by regulating metabolism is not clear. In this study, we compared the metabolomics of the livers of wild-type (WT) and MSTN mutation cattle (MT), and found changes in the content and proportion of fatty acids and bile acids in MT cattle. The differential metabolites were enriched in sterol synthesis and primary bile acid synthesis. We further analyzed the expression of genes involved in the regulation of lipid and bile acid metabolism, and found that the loss of MSTN may alter lipid synthesis and bile acid metabolism. This study provides new basic data for MSTN mutations in beef cattle breeding.

Myostatin (MSTN), a growth and differentiation factor, plays an important role in regulating skeletal muscle growth and development. MSTN knockout (MSTN-KO) leads to skeletal muscle hypertrophy and regulates metabolic homeostasis. Moreover, MSTN is also detected in smooth muscle. However, the effect of MSTN-KO on smooth muscle has not yet been reported. In this study, combined metabolome and transcriptome analyses were performed to investigate the metabolic and transcriptional profiling in esophageal smooth muscles of MSTN-KO Chinese Luxi Yellow cattle (n = 5, 24 months, average body weight 608.5 ± 17.62 kg) and wild-type (WT) Chinese Luxi Yellow cattle (n = 5, 24 months, average body weight 528.25 ± 11.03 kg). The transcriptome was sequenced using the Illumina Novaseq™ 6000 sequence platform. In total, 337 significantly up- and 129 significantly down-regulated genes were detected in the MSTN-KO cattle compared with the WT Chinese Luxi Yellow cattle. Functional enrichment analysis indicated that the DEGs were mainly enriched in 67 signaling pathways, including cell adhesion molecules, tight junction, and the cGMP-PKG signaling pathway. Metabolomics analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS) identified 130 differential metabolites between the groups, with 56 up-regulated and 74 down-regulated in MSTN knockout cattle compared with WT cattle. Differential metabolites were significantly enriched in 31 pathways, including glycerophospholipid metabolism, histidine metabolism, glutathione metabolism, and purine metabolism. Transcriptome and metabolome were combined to analyze the significant enrichment pathways, and there were three metabolically related pathways, including histidine metabolism, purine metabolism, and arginine and proline metabolism. These results provide important references for in-depth research on the effect of MSTN knockout on smooth muscle.

Myostatin (MSTN) is an important negative regulator of skeletal muscle growth in animals. A lack of MSTN promotes lipolysis and glucose metabolism but inhibits oxidative phosphorylation (OXPHOS). Here, we aimed to investigate the possible mechanism of MSTN regulating the mitochondrial energy homeostasis of skeletal muscle. To this end, MSTN knockout mice were generated by the CRISPR/Cas9 technique. Expectedly, the MSTN null (Mstn^−/−) mouse has a hypermuscular phenotype. The muscle metabolism of the Mstn^−/− mice was detected by an enzyme-linked immunosorbent assay, indirect calorimetry, ChIP-qPCR, and RT-qPCR. The resting metabolic rate and body temperature of the Mstn^−/− mice were significantly reduced. The loss of MSTN not only significantly inhibited the production of ATP by OXPHOS and decreased the activity of respiratory chain complexes, but also inhibited key rate-limiting enzymes related to the TCA cycle and significantly reduced the ratio of NADH/NAD+ in the Mstn^−/− mice, which then greatly reduced the total amount of ATP. Further ChIP-qPCR results confirmed that the lack of MSTN inhibited both the TCA cycle and OXPHOS, resulting in decreased ATP production. The reason may be that Smad2/3 is not sufficiently bound to the promoter region of the rate-limiting enzymes Idh2 and Idh3a of the TCA cycle, thus affecting their transcription.

Chinese Yellow Cattle, an ancient and domesticated breed for draft service, provide unique animal genetic resources with excellent genetic features, including crude feed tolerance, good stress resistance, strong adaptability, and tender meat quality; however, their production performance and meat yield are significantly inferior. Herein, the myostatin gene (MSTN), a negative regulator of skeletal muscle development, was knocked out by CRISPR/Cas9 technology. Eight MSTN gene-edited bull calves (MT) were born, and six of them are well-developed. Compared with the control cattle (WT), the growth trait indexes of MT cattle were generally increased, and the hindquarters especially were significantly improved. The biochemical indexes and the semen characteristics demonstrated that MT bulls were healthy and fertile. Consistent with our conjecture, the wobble and beating of MT bull spermatozoa were significantly higher than that of WT. Nine sperm motility-related proteins and nineteen mitochondrial-related proteins were identified by up-regulation in MT bull spermatozoa using FLQ proteomic technique and act to govern sperm flagellum assembly, organization, and beating and provide sufficient energy for sperm motility. The current study confirmed that the MSTN gene-edited Chinese Yellow cattle have improved growth traits and normal fertility, which can be used for beef cattle production and breeding.