MeDIP-seq and RNA-seq analysis during porcine testis development reveals functional DMR at the promoter of LDHC.

Testis development requires tight regulation of gene expression programmed by epigenetic modifiers. However, their mechanism remains to be elucidated. Here, we investigated the genome-wide DNA methylation landscape in the Duroc and Meishan boar testes using methylated DNA immunoprecipitation sequencing (MeDIP-seq). We identified over 1100 promoter differential methylation genes (DMGs) before and after puberty, most of which are associated with testis development. Furthermore, we discovered that the expression of lactate dehydrogenase C (LDHC) gene during testis development is regulated by DNA methylation. The promoter of LDHC in pre-pubertal testes is substantially methylated, whereas considerably demethylated in post-pubertal testes. Artificial demethylation with the demethylating agent 5-Aza-CdR induced LDHC expression in immature Sertoli cells (SCs). Mechanistically, we confirmed the transcription factor SP1 was recruited to bind in hypomethylated differentially methylated regions (DMRs) in LDHC promoter, which upregulated the expression of LDHC. Functionally, we demonstrated that LDHC was activated in mature SCs (mSCs) and its overexpression significantly increases lactate secretion in SCs. In conclusion, our results highlight the function and regulation of dynamic DNA methylation in testis development.

Progress on Infrared Imaging Technology in Animal Production: A Review.

Infrared thermography (IRT) imaging technology, as a convenient, efficient, and contactless temperature measurement technology, has been widely applied to animal production. In this review, we systematically summarized the principles and influencing parameters of IRT imaging technology. In addition, we also summed up recent advances of IRT imaging technology in monitoring the temperature of animal surfaces and core anatomical areas, diagnosing early disease and inflammation, monitoring animal stress levels, identifying estrus and ovulation, and diagnosing pregnancy and animal welfare. Finally, we made prospective forecast for future research directions, offering more theoretical references for related research in this field.

CircTCF4 Suppresses Proliferation and Differentiation of Goat Skeletal Muscle Satellite Cells Independent from AGO2 Binding.

The proliferation and differentiation of mammalian skeletal muscle satellite cells (MuSCs) are highly complicated. Apart from the regulatory signaling cascade driven by the protein-coding genes, non-coding RNAs such as microRNAs (miRNA) and circular RNAs (circRNAs) play essential roles in this biological process. However, circRNA functions in MuSCs proliferation and differentiation remain largely to be elucidated. Here, we screened for an exonic circTCF4 based on our previous RNA-Seq data, specifically expressed during the development of the longest dorsal muscle in goats. Subsequently, the circular structure and whole sequence of circTCF4 were verified using Sanger sequencing. Besides, circTCF4 was spatiotemporally expressed in multiple tissues from goats but strikingly enriched in muscles. Furthermore, circTCF4 suppressed MuSCs proliferation and differentiation, independent of AGO2 binding. Finally, we conducted Poly(A) RNA-Seq using cells treated with small interfering RNA targeting circTCF4 and found that circTCF4 would affect multiple signaling pathways, including the insulin signaling pathway and AMPK signaling pathway related to muscle differentiation. Our results provide additional solid evidence for circRNA regulating skeletal muscle formation.

Enhancer RNAs: transcriptional regulators and workmates of NamiRNAs in myogenesis.

miRNAs are well known to be gene repressors. A newly identified class of miRNAs termed nuclear activating miRNAs (NamiRNAs), transcribed from miRNA loci that exhibit enhancer features, promote gene expression via binding to the promoter and enhancer marker regions of the target genes. Meanwhile, activated enhancers produce endogenous non-coding RNAs (named enhancer RNAs, eRNAs) to activate gene expression. During chromatin looping, transcribed eRNAs interact with NamiRNAs through enhancer-promoter interaction to perform similar functions. Here, we review the functional differences and similarities between eRNAs and NamiRNAs in myogenesis and disease. We also propose models demonstrating their mutual mechanism and function. We conclude that eRNAs are active molecules, transcriptional regulators, and partners of NamiRNAs, rather than mere RNAs produced during enhancer activation.

CircRNA-Protein Interactions in Muscle Development and Diseases.

Circular RNA (circRNA) is a kind of novel endogenous noncoding RNA formed through back-splicing of mRNA precursor. The biogenesis, degradation, nucleus-cytoplasm transport, location, and even translation of circRNA are controlled by RNA-binding proteins (RBPs). Therefore, circRNAs and the chaperoned RBPs play critical roles in biological functions that significantly contribute to normal animal development and disease. In this review, we systematically characterize the possible molecular mechanism of circRNA-protein interactions, summarize the latest research on circRNA-protein interactions in muscle development and myocardial disease, and discuss the future application of circRNA in treating muscle diseases. Finally, we provide several valid prediction methods and experimental verification approaches. Our review reveals the significance of circRNAs and their protein chaperones and provides a reference for further study in this field.

Identification of IGF2BP1-related lncRNA-miRNA-mRNA network in goat skeletal muscle satellite cells.

Insulin-like growth factor 2 mRNA-binding protein 1 (IGF2BP1) plays essential roles in the proliferation of skeletal muscle satellite cells (MuSCs). Increasing evidence has shown that IGF2BP1 regulates the expression of noncoding RNAs and mRNAs. However, the related molecular network remains to be fully understood. Therefore, we performed RNA sequencing and analyzed the microRNAs (miRNAs), long noncoding RNAs (lncRNAs), and mRNAs differentially expressed in goat MuSCs treated with IGF2BP1 overexpressing and empty vectors. A total of 36 miRNAs, 59 lncRNAs, and 44 mRNAs were differentially expressed caused by IGF2BP1. Expectedly, they were enriched in muscle development-related Rap1, PI3K-AKT, and FoxO signaling pathways. Finally, we constructed a lncRNA-miRNA-mRNA interaction network containing 30 lncRNAs, 15 miRNAs, and 34 mRNAs, in which several miRNAs, including miR-133a-3p, miR-204-5p, miR-125a-3p, miR-145-3p, and miR-423-5p, relate with cell growth and participate in muscle development. Overall, we constructed an IGF2BP1-related network, which provides new insight into the myogenic proliferation of goat.