bta-miR-378 promote the differentiation of bovine skeletal muscle-derived satellite cells

Ythdf2 facilitates precursor miR-378/miR-378-5p maturation to support myogenic differentiation

Ythdf2 is known to mediate mRNA degradation in an m6A-dependent manner, and it has been shown to play a role in skeletal muscle differentiation. Recently, Ythdf2 was also found to bind to m6A-modified precursor miRNAs and regulate their maturation. However, it remains unknown whether this mechanism is related to the regulation of myogenesis by Ythdf2. Here, we observed that Ythdf2 knockdown significantly suppressed myotube formation and impacted miRNAs expression during myogenic differentiation. Through integrated analysis of miRNA and mRNA sequencing data, miR-378 and miR-378-5p were identified as important targets of Ythdf2 in myogenesis. Mechanically, Ythdf2 was found to interact with core components of the pre-miRNA processor complex, namely DICER1 and TARBP2, thereby facilitating the maturation of pre-miR-378/miR-378-5p in an m6A-dependent manner and resulting in an increase in the expression levels of mature miR-378 and miR-378-5p. Moreover, the downregulation of either miR-378 or miR-378-5p significantly inhibited myotube formation, while the forced expression of miR-378 or miR-378-5p could partially rescued Ythdf2 knockdown-induced suppression of myogenic differentiation by activating the mTOR pathway. Collectively, our results for the first time suggest that Ythdf2 regulates myogenic differentiation via mediating pre-miR-378/miR-378-5p maturation, which might provide new insights into the molecular mechanisms underlying m6A modification in the regulation of myogenesis.

Regulation of myo-miR-24-3p on the Myogenesis and Fiber Type Transformation of Skeletal Muscle

Skeletal muscle plays critical roles in providing a protein source and contributing to meat production. It is well known that microRNAs (miRNAs) exert important effects on various biological processes in muscle, including cell fate determination, muscle fiber morphology, and structure development. However, the role of miRNA in skeletal muscle development remains incompletely understood. In this study, we observed a critical miRNA, miR-24-3p, which exhibited higher expression levels in Tongcheng (obese-type) pigs compared to Landrace (lean-type) pigs. Furthermore, we found that miR-24-3p was highly expressed in the dorsal muscle of pigs and the quadriceps muscle of mice. Functionally, miR-24-3p was found to inhibit proliferation and promote differentiation in muscle cells. Additionally, miR-24-3p was shown to facilitate the conversion of slow muscle fibers to fast muscle fibers and influence the expression of GLUT4, a glucose transporter. Moreover, in a mouse model of skeletal muscle injury, we demonstrated that overexpression of miR-24-3p promoted rapid myogenesis and contributed to skeletal muscle regeneration. Furthermore, miR-24-3p was found to regulate the expression of target genes, including Nek4, Pim1, Nlk, Pskh1, and Mapk14. Collectively, our findings provide evidence that miR-24-3p plays a regulatory role in myogenesis and fiber type conversion. These findings contribute to our understanding of human muscle health and have implications for improving meat production traits in livestock.

Integrated Transcriptome Analysis of miRNAs and mRNAs in the Skeletal Muscle of Wuranke Sheep

MicroRNAs (miRNAs) are regarded as important regulators in skeletal muscle development. To reveal the regulatory roles of miRNAs and their target mRNAs underlying the skeletal muscle development of Wuranke sheep, we investigated the miRNA and mRNA expression profiles in the biceps femoris of these sheep at the fetal (3 months of gestation) and 3- and 15-month-old postnatal stages. Consequently, a total of 1195 miRNAs and 24,959 genes were identified. Furthermore, 474, 461, and 54 differentially expressed miRNAs (DEMs) and 6783, 7407, and 78 differentially expressed genes (DEGs) were detected among three comparative groups. Functional analysis demonstrated that the target mRNAs of the DEMs were enriched in multiple pathways related to muscle development. Moreover, the interactions among several predicted miRNA-mRNA pairs (oar-miR-133-HDAC1, oar-miR-1185-5p-MYH1/HADHA/OXCT1, and PC-5p-3703_578-INSR/ACTG1) that potentially affect skeletal muscle development were verified using dual-luciferase reporter assays. In this study, we identified the miRNA and mRNA differences in the skeletal muscle of Wuranke sheep at different developmental stages and revealed that a series of candidate miRNA-mRNA pairs may act as modulators of muscle development. These results will contribute to future studies on the function of miRNAs and their target mRNAs during skeletal muscle development in Wuranke sheep.

MicroRNAs as serum biomarker for Senecio brasiliensis poisoning in cattle

Senecio spp. is one of the most frequent plant-related poisonings in cattle. Its ingestion generates the disease seneciosis, characterized by hepatic damages. Liver biopsies and serum markers dosage are tools used in diagnosis; however, many breeding cattle are undiagnosed. MicroRNAs are non-coding RNA, stable in biological fluids. Their difference in expression levels may indicate the presence of the poisoning. We analyzed the miRNA profiling to identify potential diagnostic biomarkers for Senecio brasiliensis poisoning. The expression of miR-21, miR-885, miR-122, miR-181b, miR-30a, miR-378, and let-7 f were evaluated in the serum of exposed cattle. At least one histological change was found in liver and lower quantity of albumin and high AST and ALP were also detected. MiRNAs miR-30a, miR-378, miR-21, miR-885, and miR-122 presented significantly higher expression in intoxicated animals than in healthy animals. Furthermore, miR-122, miR-885, and, especially, miR-21 signatures demonstrated high sensitivity and specificity, with potential application for detecting poisoning.

Multi-Omics Analysis of Key microRNA-mRNA Metabolic Regulatory Networks in Skeletal Muscle of Obese Rabbits

microRNAs (miRNAs), small non-coding RNA with a length of about 22 nucleotides, are involved in the energy metabolism of skeletal muscle cells. However, their molecular mechanism of metabolism in rabbit skeletal muscle is still unclear. In this study, 16 rabbits, 8 in the control group (CON-G) and 8 in the experimental group (HFD-G), were chosen to construct an obese model induced by a high-fat diet fed from 35 to 70 days of age. Subsequently, 54 differentially expressed miRNAs, 248 differentially expressed mRNAs, and 108 differentially expressed proteins related to the metabolism of skeletal muscle were detected and analyzed with three sequencing techniques (small RNA sequencing, transcriptome sequencing, and tandem mass tab (TMT) protein technology). It was found that 12 miRNAs and 12 core genes (e.g., CRYL1, VDAC3 and APIP) were significantly different in skeletal muscle from rabbits in the two groups. The network analysis showed that seven miRNA-mRNA pairs were involved in metabolism. Importantly, two miRNAs (miR-92a-3p and miR-30a/c/d-5p) regulated three transcription factors (MYBL2, STAT1 and IKZF1) that may be essential for lipid metabolism. These results enhance our understanding of molecular mechanisms associated with rabbit skeletal muscle metabolism and provide a basis for future studies in the metabolic diseases of human obesity.

Integrated analysis of deregulation microRNA expression in head and neck squamous cell carcinoma

MicroRNAs (miRNAs) play critical roles in carcinogenesis and development of cancers. In this study, we analyzed the eccentrically expressed miRNAs in head and neck squamous cell carcinoma (HNSCC) tissues based on the miRNA-Seq data of HNSCC patients available in the Cancer Genome Atlas database. Aberrant expression of 2589 miRNAs was detected in HNSCC tissues (1128 downregulated and 1461 upregulated). The differential expression levels of the miRNAs were further validated by analysis of 25 HNSCC samples and paired control tissues and compared with the Gene Expression Omnibus database to determine the candidate miRNAs. Quantitative reverse transcription polymerase chain reaction was used to compare the expression of these candidate miRNAs between 22 fresh HNSCC tissue samples and 11 control samples. In addition, the relationship between the expression of these candidate miRNAs and Tumor, Node, Metastases staging of HNSCC was analyzed. Compared with the expression in control tissues, the levels of hsa-miR-410-3p, hsa-miR-411-5p, hsa-miR-125b-2-3p, and hsa-miR-99a-3p were significantly lower in HNSCC. According to the Cancer Genome Atlas dataset analyzed, all 4 miRNAs were shown to inhibit tumor progression (T stage), positive lymph node metastasis (N stage), and distant metastasis (M stage) in HNSCC. Kyoto Encyclopedia of Genes and Genomes analysis showed that genes regulated by these 4 miRNAs were enriched in certain pathways, including the transforming growth factor-β signaling pathway and the Hippo pathway. Enriched gene ontology terms mainly included regulation of transcription, cell proliferation, and apoptosis, which are well-characterized functions of miRNAs. Moreover, all 4 miRNAs inhibited the progression of primary tumors (T stage) and metastasis of regional lymph nodes (N stage). The top 4 aberrantly expressed miRNAs identified in this study have great clinical value in developing strategies for early diagnosis and treatment of HNSCC. More intensive studies are required to elucidate the mechanism underlying the roles of these miRNAs in HNSCC.

Tiny Regulators of Massive Tissue: MicroRNAs in Skeletal Muscle Development, Myopathies, and Cancer Cachexia

Skeletal muscles are the largest tissues in our body and the physiological function of muscle is essential to every aspect of life. The regulation of development, homeostasis, and metabolism is critical for the proper functioning of skeletal muscle. Consequently, understanding the processes involved in the regulation of myogenesis is of great interest. Non-coding RNAs especially microRNAs (miRNAs) are important regulators of gene expression and function. MiRNAs are small (~22 nucleotides long) noncoding RNAs known to negatively regulate target gene expression post-transcriptionally and are abundantly expressed in skeletal muscle. Gain- and loss-of function studies have revealed important roles of this class of small molecules in muscle biology and disease. In this review, we summarize the latest research that explores the role of miRNAs in skeletal muscle development, gene expression, and function as well as in muscle disorders like sarcopenia and Duchenne muscular dystrophy (DMD). Continuing with the theme of the current review series, we also briefly discuss the role of miRNAs in cancer cachexia.

miR-194-5p negatively regulates the proliferation and differentiation of rabbit skeletal muscle satellite cells

Skeletal muscle satellite cells (SMSCs), also known as a multipotential stem cell population, play a crucial role during muscle growth and regeneration. In recent years, numerous miRNAs have been associated with the proliferation and differentiation of SMSCs in a number of mammalian species; however, the regulatory mechanisms of miR-194-5p in rabbit SMSCs still remain scarce. In this study, miR-194-5p was first observed to be highly expressed in the rabbit leg muscle. Furthermore, both the mimics and inhibitor of miR-194-5p were used to explore its role in the proliferation and differentiation of rabbit SMSCs cultured in vitro. Results from both EdU and CCK8 assays showed that miR-194-5p inhibited the proliferation of SMSCs. Meanwhile, Mef2c was identified as a target gene of miR-194-5p based on the dual-luciferase reporter assay results. In addition, upregulation of miR-194-5p decreased the expression levels of Mef2c and MyoG during rabbit SMSCs differentiation on Days 3 and 7 of in vitro culture. Taken together, these data demonstrated that miR-194-5p negatively regulates the proliferation and differentiation of rabbit SMSCs by targeting Mef2c.

Differential expression profile of microRNA in yak skeletal muscle and adipose tissue during development

BACKGROUND

miRNAs play an important role in regulating normal animal development. Muscle tissue and fat metabolism are important for maintaining energy balance in animals. Yak has important agricultural and economic importance as it provides milk, meat, and hair. It is used for transportation as well. However, the miRNA expression profiles of their muscle and adipose tissue are currently unknown.

OBJECTIVE

To explore the regulatory roles of miRNAs in the skeletal muscle and adipose tissues of yak.

METHODS

A total of 12 small RNA libraries were constructed from the skeletal muscle and adipose samples from yak aged 0.5, 2.5, 4.5, and 7.5 years. High-throughput sequencing and bioinformatics analysis were used to determine the dynamic expression profile of miRNA, and a miRNA regulatory network related to muscle and adipose tissue development was established.

RESULTS

miR-1-3p and miR-143-3p showed the highest expression during yak skeletal muscle and fat development, respectively. The MAPK and Ras signaling pathways were the pivotal pathways. miR-181-5p, miR-542-3p, and miR-424-5p may have key roles in skeletal muscle development, and CREBRF, GRB10, CDK1, RFX3, and EPC2 were the core target genes. While miR-127-5p, miR-379-3p, and miR-494-3p may play important regulatory roles in adipose deposition, and ETV1, XPO7, and C5AR2 were the core target genes.

CONCLUSION

This study provides valuable resources for further study of the molecular mechanisms underlying yak skeletal muscle and adipose tissue development, and also a basis for studying the interactions between genes and miRNAs.

Satellite cells and their regulation in livestock

Satellite cells are the myogenic stem and progenitor population found in skeletal muscle. These cells typically reside in a quiescent state until called upon to support repair, regeneration, or muscle growth. The activities of satellite cells are orchestrated by systemic hormones, autocrine and paracrine growth factors, and the composition of the basal lamina of the muscle fiber. Several key intracellular signaling events are initiated in response to changes in the local environment causing exit from quiescence, proliferation, and differentiation. Signals emanating from Notch, wingless-type mouse mammary tumor virus integration site family members, and transforming growth factor-β proteins mediate the reversible exit from growth 0 phase while those initiated by members of the fibroblast growth factor and insulin-like growth factor families direct proliferation and differentiation. Many of these pathways impinge upon the myogenic regulatory factors (MRF), myogenic factor 5, myogenic differentiation factor D, myogenin and MRF4, and the lineage determinate, Paired box 7, to alter transcription and subsequent satellite cell decisions. In the recent past, insight into mouse transgenic models has led to a firm understanding of regulatory events that control satellite cell metabolism and myogenesis. Many of these niche-regulated functions offer subtle differences from their counterparts in livestock pointing to the existence of species-specific controls. The purpose of this review is to examine the mechanisms that mediate large animal satellite cell activity and their relationship to those present in rodents.

Bta-miR-24-3p Controls the Myogenic Differentiation and Proliferation of Fetal, Bovine, Skeletal Muscle-Derived Progenitor Cells by Targeting ACVR1B

Simple Summary

MicroRNAs play pivotal roles in skeletal muscle development, but the molecular basis of their functions in fetal bovine skeletal muscle development is largely unknown. Here, we report a mechanistic study of bta-miR-24-3p, a key miRNA regulator of the myogenic differentiation of fetal bovine platelet-derived growth factor receptor alpha negative (PDGFRα^-) progenitor cells. We isolated progenitor cells from the bovine fetal longissimus dorsi muscle and purified them with PDGFRα antibodies to remove fibro-adipogenic progenitors. We observed elevated bta-miR-24-3p expression during differentiation, and bta-miR-24-3p overexpression led to promoted myogenic differentiation but suppressed proliferation. Moreover, activin receptor type 1B (ACVR1B) was identified as a direct target of bta-miR-24-3p, and ACVR1B-silencing cells exhibited similar phenotypes to bta-miR-24-3p-overexpressing bovine PDGFRα^- progenitor cells. These results extended our understanding on the roles of miRNA in fetal muscle development. The method of removing fibro-adipogenic progenitors in our study will also provide useful information for other investigators.

Abstract

MicroRNAs modulate a variety of cellular events, including skeletal muscle development, but the molecular basis of their functions in fetal bovine skeletal muscle development is poorly understood. In this study, we report that bta-miR-24-3p promotes the myogenic differentiation of fetal bovine PDGFRα^- progenitor cells. The expression of bta-miR-24-3p increased during myogenic differentiation. Overexpression of bta-miR-24-3p significantly promoted myogenic differentiation, but inhibited proliferation. A dual-luciferase assay identified ACVR1B as a direct target of bta-miR-24-3p. Similarly, knocking down ACVR1B by RNA interference also significantly inhibited proliferation and promoted the differentiation of bovine PDGFRα^- progenitor cells. Thus, our study provides a mechanism in which bta-miR-24-3p regulates myogenesis by inhibiting ACVR1B expression.

MiR-17 and miR-19 cooperatively promote skeletal muscle cell differentiation

Skeletal myogenesis is a highly coordinated process that involves cell proliferation, differentiation and fusion controlled by a complex gene regulatory network. The microRNA gene cluster miR-17–92 has been shown to be related to this process; however, the exact role of each cluster member remains unclear. Here, we show that miR-17 and miR-20a could effectively promote the differentiation of both C2C12 myoblasts and primary bovine satellite cells. In contrast, miR-18a might play a negative role in C2C12 cell differentiation, while miR-19 and miR-92a had little influence. Transcriptome and target analyses revealed that miR-17 could act on Ccnd2, Jak1 and Rhoc genes that are critical for cell proliferation and/or fusion. Notably, the addition of miR-19 could reverse the lethal effect of miR-17 and could thus facilitate the maturation of myotubes. Furthermore, by co-injecting the lentiviral shRNAs of miR-17 and miR-19 into mouse tibialis anterior muscles, we demonstrated the wound healing abilities of the two miRNAs. Our findings indicate that in combination with miR-19, miR-17 is a potent inducer of skeletal muscle differentiation.