Epigenetic Regulation Mechanisms of the Cofilin-1 Gene in the Development and Differentiation of Bovine Primary Myoblasts

Identification cloning and functional analysis of novel natural antisense lncRNA CFL1-AS1 in cattle

Long noncoding RNAs have been identified as important regulators of gene expression and animal development. The expression of natural antisense transcripts (NATs) transcribed in the opposite direction to protein-coding genes is usually positively correlated with the expression of homologous sense genes and is the key factor for expression. Here, we identified a conserved noncoding antisense transcript, CFL1-AS1, that plays an important role in muscle growth and development. CFL1-AS1 overexpression and knockout vectors were constructed and transfected into 293T and C2C12 cells. CFL1-AS1 positively regulated CFL1 gene expression, and the expression of CFL2 was also downregulated when CFL1-AS1 was knocked down. CFL1-AS1 promoted cell proliferation, inhibited apoptosis and participated in autophagy. This study expands the research on NATs in cattle and lays a foundation for the study of the biological function of bovine CFL1 and its natural antisense chain transcript CFL1-AS1 in bovine skeletal muscle development. The discovery of this NAT can provide a reference for subsequent genetic breeding and data on the characteristics and functional mechanisms of NATs.

Role of Actin-Binding Proteins in Skeletal Myogenesis

Maintenance of skeletal muscle quantity and quality is essential to ensure various vital functions of the body. Muscle homeostasis is regulated by multiple cytoskeletal proteins and myogenic transcriptional programs responding to endogenous and exogenous signals influencing cell structure and function. Since actin is an essential component in cytoskeleton dynamics, actin-binding proteins (ABPs) have been recognized as crucial players in skeletal muscle health and diseases. Hence, dysregulation of ABPs leads to muscle atrophy characterized by loss of mass, strength, quality, and capacity for regeneration. This comprehensive review summarizes the recent studies that have unveiled the role of ABPs in actin cytoskeletal dynamics, with a particular focus on skeletal myogenesis and diseases. This provides insight into the molecular mechanisms that regulate skeletal myogenesis via ABPs as well as research avenues to identify potential therapeutic targets. Moreover, this review explores the implications of non-coding RNAs (ncRNAs) targeting ABPs in skeletal myogenesis and disorders based on recent achievements in ncRNA research. The studies presented here will enhance our understanding of the functional significance of ABPs and mechanotransduction-derived myogenic regulatory mechanisms. Furthermore, revealing how ncRNAs regulate ABPs will allow diverse therapeutic approaches for skeletal muscle disorders to be developed.

Global DNA Methylation, miRNA, and mRNA Profiles in Sheep Skeletal Muscle Promoted by Hybridization

With the development of high-throughput sequencing technology, several nongenetic variations, including noncoding RNAs such as miRNAs, and DNA methylation, have been found to play an important role in animal muscle development and fat metabolism. In this study, Southdown and Suffolk were selected as male parents for hybridization with Hu sheep (Southdown × Hu (NH), Suffolk × Hu (SH), and Hu × Hu (HH)). RNA sequencing, bisulfite sequencing, and small-RNA sequencing were used to study the methylation patterns and differences in miRNA and mRNA expression in the F1 sheep longissimus dorsi muscle tissue. We identified 765 differentially expressed genes (DEGs), 10,161 differentially methylated regions (DMRs), and 164 differentially expressed miRNAs, which were significantly enriched in AMPK signaling, fatty acid degradation, metabolism, and other related pathways (P < 0.05). In addition, we constructed a DNA methylation-mRNA and miRNA-mRNA coexpression network. A total of 42 common genes were identified from DMRs and DEGs. Importantly, we predicted that 33 differentially expressed miRNAs directly or indirectly targeted the SLC27A6. The data obtained in this study provide useful information and evidence to support further understanding of the miRNA and DNA methylation of key genes regulating muscle growth and fat metabolism in hybrid sheep populations.

New Insight into Muscle-Type Cofilin (CFL2) as an Essential Mediator in Promoting Myogenic Differentiation in Cattle

Meat quality and meat composition are not separated from the influences of animal genetic improvement systems; the growth and development of skeletal muscle are the primary factors in agricultural meat production and meat quality. Though the muscle-type cofilin (CFL2) gene has a crucial influence on skeletal muscle fibers and other related functions, the epigenetic modification mechanism of the CFL2 gene regulating meat quality remains elusive. After exploring the spatiotemporal expression data of CFL2 gene in a group of samples from fetal bovine, calf, and adult cattle, we found that the level of CFL2 gene in muscle tissues increased obviously with cattle age, whereas DNA methylation levels of CFL2 gene in muscle tissues decreased significantly along with cattle age by BSP and COBRA, although DNA methylation levels and mRNA expression levels basically showed an opposite trend. In cell experiments, we found that bta-miR-183 could suppress primary bovine myoblast differentiation by negatively regulated CFL2. In addition, we packaged recombinant adenovirus vectors for CFL2 gene knockout and overexpression and found that the CFL2 gene could promote the differentiation of primary bovine myoblasts by regulating marker genes MYOD, MYOG and MYH3. Therefore, CFL2 is an essential mediator for promoting myogenic differentiation by regulating myogenic marker genes in cattle myoblasts.