A Novel Mechanism of bta-miR-210 in Bovine Early Intramuscular Adipogenesis

Research progress of non-coding RNAs regulation on intramuscular adipocytes in domestic animals

Intramuscular fat (IMF) is the main determinant of the economic value of domestic animal meat, and has a vital impact on the sensory quality characteristics, while the content of IMF is mainly determined by the size and number of intramuscular adipocytes. In recent years, due to the development of sequencing technology and omics technology, a large number of non-coding RNAs have been identified in intramuscular adipocytes. Non-coding RNAs are a kind of RNA regulatory factors with biological functions but without translation function, which mainly include microRNAs (miRNAs), long non-coding RNAs (lncRNAs) and circular RNAs (circRNAs). These non-coding RNAs regulate the key genes of intramuscular adipocyte growth and development at post-transcriptional level through a variety of regulatory mechanisms, and affect the number and size of intramuscular adipocytes, thus affecting the content of IMF. Here, the review summarizes the candidate non-coding RNAs (miRNAs, lncRNAs, circRNAs) and genes involved in the regulation of intramuscular adipocytes, the related regulation mechanism and signaling pathways, in order to provide reference for further clarifying the molecular regulation mechanism of non-coding RNAs on intramuscular adipocytes in domestic animals.

CircRNA Profiling Reveals an Abundant circBDP1 that Regulates Bovine Fat Development by Sponging miR-181b/miR-204 Targeting Sirt1/TRARG1

The proliferation and differentiation of preadipocytes is an important factor determining bovine fat development, which is closely related to the feed conversion ratio, carcass traits, and beef quality. The purpose of this study was to identify the effects of candidate circRNA and miRNA on the proliferation and differentiation of bovine preadipocytes in order to provide basic materials for molecular breeding in cattle. circRNA sequencing was performed on bovine adipocyte samples at different differentiation time points, and a total of 1830 differentially expressed circRNAs were identified. Among them, circBDP1, derived from the bovine BDP1 gene, has potential binding sites for miR-204 (known as a regulator of bovine fat development) and miR-181b, which gives us a hint that circBDP1 may regulate bovine fat development by adsorbing miR-204 and miR-181b. Here, our results revealed that circBDP1 overexpression promoted the proliferation and differentiation of bovine preadipocytes. The miRNA profile of bovine adipocytes at different differentiation time points was also analyzed using the small RNA sequencing method, and a total of 89 differentially expressed miRNAs were identified, including miR-204 and miR-181b. As expected, dual-luciferase reporter results showed that circBDP1 competitively adsorbed miR-181b and miR-204. Overexpression and interference of miR-181b in bovine preadipocytes and 3T3-L1 showed that miR-181b promoted the proliferation and differentiation of preadipocytes. Further results displayed that miR-181b and miR-204 simultaneously targeted the SIRT1 gene, and miR-204 also targeted the 3' UTR region of the TRARG1 gene. In summary, this study found that miR-181b and miR-204 were involved in fat development by targeting SIRT1 and TRARG1. The results of this study will lay a foundation for the research of fat development and beef cattle industry.

In Silico Analysis of the Gene Expression Patterns between Aldosterone-Producing Adenoma and Nonfunctional Adrenocortical Adenoma

Primary aldosteronism is the most common form of secondary hypertension, and aldosteronoma makes up a significant proportion of primary aldosteronism cases. Aldosteronoma is also called aldosterone-producing adenoma (APA). Although there have been many studies about APA, the pathogenesis of this disease is not yet fully understood. In this study, we aimed to find out the difference of gene expression patterns between APA and nonfunctional adrenocortical adenoma (NFAA) using a weighted gene coexpression network (WGCNA) and differentially expressed gene (DEG) analysis; only the genes that meet the corresponding standards of both methods were defined as real hub genes and then used for further analysis. Twenty-nine real hub genes were found out, most of which were enriched in the phospholipid metabolic process. WISP2, S100A10, SSTR5-AS1, SLC29A1, APOC1, and SLITRK4 are six real hub genes with the same gene expression pattern between the combined and validation datasets, three of which indirectly or directly participate in lipid metabolism including WISP2, S100A10, and APOC1. According to the gene expression pattern of DEGs, we speculated five candidate drugs with potential therapeutic value for APA, one of which is cycloheximide, an inhibitor for phospholipid biosynthesis. All the evidence suggests that phospholipid metabolism may be an important pathophysiological mechanism for APA. Our study provides a new perspective regarding the pathophysiological mechanism of APA and offers some small molecules that may possibly be effective drugs against APA.

ncRNAs regulate bovine adipose tissue deposition

Lipid metabolism, which encompasses synthesis and degradation of lipids, is critical for a wide range of cellular functions, including structural and morphological properties of organelles, energy storage, signalling, and the stability and function of membrane proteins. Adipose tissue is a dynamic tissue type that performs a lot of significant physiological functions, including secretion, and is involved in maintaining homeostasis and in regulatory roles of other tissues based on paracrine or endocrine. More recently, several classes of non-coding RNAs (ncRNAs), such as long non-coding RNA (lncRNA), microRNA (miRNA) and circular RNA (circRNA), have been discovered in adipocytes, and they act as critical regulators of gene expression in adipogenesis and regulate adipogenesis through multiple pathways. In the present paper, we discussed several classes of non-coding RNAs and summarized the latest research on the regulatory role of ncRNAs in bovine adipogenesis. We gave examples for known modes of action to look forward to providing reference information future scientific research in cattle breeding.

Bovine Pre-adipocyte Adipogenesis Is Regulated by bta-miR-150 Through mTOR Signaling

Micro RNA (miR) are recognized for their important roles in biological processes, particularly in regulatory componentization. Among the miR, miR-150 has been the focus of intense scrutiny, mostly due to its role in malignant tumors. A comparison between steer and bull adipose tissues identified bta-miR-150 as one of the nine downregulated miRNAs, although its function remains unknown (GEO:GSE75063). The present study aimed to further characterize the role of bta-miR-150 in cattle. bta-miR-150 has a negative regulatory effect on the differentiation of bovine adipocytes and promotes proliferation. Overexpression of bta-miR-150 can promote mRNA and protein expression of the marker genes CDK1, CDK2, and PCNA, increase the number of EdU-stained cells, promote adipocyte proliferation, inhibit adipocyte differentiation, and reduce lipid droplet formation. Results of RNA-seq and WGCNA analyses showed that the mammalian target of the rapamycin signaling pathway, which plays a major regulatory role, is dysregulated by the overexpression and inhibition of miR-150. We found that the target gene of bta-miR-150 is AKT1 and that bta-miR-150 affects AKT1 phosphorylation levels. These results showed that bta-miR-150 plays a role in adipogenic differentiation and might therefore have applications in the beef industry.