miR-424 Promotes Bovine Adipogenesis Through an Unconventional Post-Transcriptional Regulation of STK11

A review of the role of transcription factors in regulating adipogenesis and lipogenesis in beef cattle

In the past few decades, genomic selection and other refined strategies have been used to increase the growth rate and lean meat production of beef cattle. Nevertheless, the fast growth rates of cattle breeds are often accompanied by a reduction in intramuscular fat (IMF) deposition, impairing meat quality. Transcription factors play vital roles in regulating adipogenesis and lipogenesis in beef cattle. Meanwhile, understanding the role of transcription factors in regulating adipogenesis and lipogenesis in beef cattle has gained significant attention to increase IMF deposition and meat quality. Therefore, the aim of this paper was to provide a comprehensive summary and valuable insight into the complex role of transcription factors in adipogenesis and lipogenesis in beef cattle. This review summarizes the contemporary studies in transcription factors in adipogenesis and lipogenesis, genome-wide analysis of transcription factors, epigenetic regulation of transcription factors, nutritional regulation of transcription factors, metabolic signalling pathways, functional genomics methods, transcriptomic profiling of adipose tissues, transcription factors and meat quality and comparative genomics with other livestock species. In conclusion, transcription factors play a crucial role in promoting adipocyte development and fatty acid biosynthesis in beef cattle. They control adipose tissue formation and metabolism, thereby improving meat quality and maintaining metabolic balance. Understanding the processes by which these transcription factors regulate adipose tissue deposition and lipid metabolism will simplify the development of marbling or IMF composition in beef cattle.

Bioinformatics Analysis of miR-181a and Its Role in Adipogenesis, Obesity, and Lipid Metabolism Through Review of Literature

The miRNAs regulate various biological processes in the mammalian body system. The role of miR-181a in the development, progression, and expansion of cancers is well-documented. However, the role of miR-181a in adipogenesis; lipid metabolism; obesity; and obesity-related issues such as diabetes mellitus needs to be explored. Therefore, in the present study, the literature was searched and bioinformatics tools were applied to explore the role of miR-181a in adipogenesis. The list of adipogenic and lipogenic target genes validated through different publications were extracted and compiled. The network and functional analysis of these target genes was performed through in-silico analysis. The mature sequence of miR-181a of different species were extracted from and were found highly conserved among the curated species. Additionally, we also used various bioinformatics tools such as target gene extraction from Targetscan, miRWalk, and miRDB, and the list of the target genes from these different databases was compared, and common target genes were predicted. These common target genes were further subjected to the enrichment score and KEGG pathways analysis. The enrichment score of the vital KEGG pathways of the target genes is the key regulator of adipogenesis, lipogenesis, obesity, and obesity-related syndromes in adipose tissues. Therefore, the information presented in the current review will explore the regulatory roles of miR-181a in fat tissues and its associated functions and manifestations.

Emerging Roles of Non-Coding RNAs in the Feed Efficiency of Livestock Species

A global population of already more than seven billion people has led to an increased demand for food and water, and especially the demand for meat. Moreover, the cost of feed used in animal production has also increased dramatically, which requires animal breeders to find alternatives to reduce feed consumption. Understanding the biology underlying feed efficiency (FE) allows for a better selection of feed-efficient animals. Non-coding RNAs (ncRNAs), especially micro RNAs (miRNAs) and long non-coding RNAs (lncRNAs), play important roles in the regulation of bio-logical processes and disease development. The functions of ncRNAs in the biology of FE have emerged as they participate in the regulation of many genes and pathways related to the major FE indicators, such as residual feed intake and feed conversion ratio. This review provides the state of the art studies related to the ncRNAs associated with FE in livestock species. The contribution of ncRNAs to FE in the liver, muscle, and adipose tissues were summarized. The research gap of the function of ncRNAs in key processes for improved FE, such as the nutrition, heat stress, and gut–brain axis, was examined. Finally, the potential uses of ncRNAs for the improvement of FE were discussed.

High-Throughput miRFluR Platform Identifies miRNA Regulating B3GLCT That Predict Peters' Plus Syndrome Phenotype, Supporting the miRNA Proxy Hypothesis

MicroRNAs (miRNAs, miRs) finely tune protein expression and target networks of hundreds to thousands of genes that control specific biological processes. They are critical regulators of glycosylation, one of the most diverse and abundant post-translational modifications. In recent work, miRs have been shown to predict the biological functions of glycosylation enzymes, leading to the "miRNA proxy hypothesis" which states, "if a miR drives a specific biological phenotype..., the targets of that miR will drive the same biological phenotype." Testing of this powerful hypothesis is hampered by our lack of knowledge about miR targets. Target prediction suffers from low accuracy and a high false prediction rate. Herein, we develop a high-throughput experimental platform to analyze miR-target interactions, miRFluR. We utilize this system to analyze the interactions of the entire human miRome with beta-3-glucosyltransferase (B3GLCT), a glycosylation enzyme whose loss underpins the congenital disorder Peters' Plus Syndrome. Although this enzyme is predicted by multiple algorithms to be highly targeted by miRs, we identify only 27 miRs that downregulate B3GLCT, a >96% false positive rate for prediction. Functional enrichment analysis of these validated miRs predicts phenotypes associated with Peters' Plus Syndrome, although B3GLCT is not in their known target network. Thus, biological phenotypes driven by B3GLCT may be driven by the target networks of miRs that regulate this enzyme, providing additional evidence for the miRNA proxy hypothesis.

Integrated microRNA-mRNA analysis reveals the roles of microRNAs in the muscle fat metabolism of Yanbian cattle

Fat deposition is an important economic trait in farm animals. However, it is difficult to genetically improve intramuscular fat deposition via trait-based cattle breeding. The main objectives of this study were to analyze the factors about beef flavor, and to detect functional microRNA (miRNA, miR) associated with intramuscular fat deposition in Yanbian cattle. Longissimus dorsi samples from six steers were separated into high- and low-fat groups (n = 3 each) based on the marbling score, and transcriptomic analysis was performed using miRNA sequencing. A total of 33 miRNAs and 38 genes were found to be differentially expressed in the high- and low-fat groups. Quantitative real-time polymerase chain reaction was performed to validate the sequencing results. Integrated miRNA-mRNA analysis revealed that miRNA-associated target genes were primarily associated with skeletal muscle development. However, some of the miRNAs (miR-424 etc.) and genes (ATF3 etc.) were also associated with fat metabolism. A targeted relationship between miR-22-3p and the WFIKKN2 gene and its involvement in adipocyte differentiation were confirmed experimentally. The study findings may provide potential candidate molecular targets for the selection of cattle with improved meat quality.

MicroRNA-489-3p promotes adipogenesis by targeting the Postn gene in 3T3-L1 preadipocytes

AIMS

Accumulating evidence indicates that a number of microRNAs (miRNAs) serve as essential regulators during adipogenesis and adipolysis in humans and animals and play critical roles in the development of fat tissue. In this study, we aimed to determine the functional role and underlying regulatory mechanism of microRNA-489-3p (miR-489) in adipocytes.

MATERIALS AND METHODS

The expression patterns of miR-489 in mice were measured by qRT-PCR. Overexpression and knockdown of miR-489 by mimic and inhibitor transfections in 3T3-L1 preadipocytes revealed the regulatory effect of miR-489 on cellular proliferation and differentiation and energy turnover. Furthermore, RNA-seq, bioinformatics prediction, and dual luciferase reporter assays were used to identify the direct target of miR-489.

KEY FINDINGS

The results showed that miR-489 was highly expressed in the visceral fat tissue of adult mice, and obese mice exhibited higher levels of miR-489 than normal mice. Overexpression of miR-489 suppressed proliferation but promoted adipogenic differentiation and lipid accumulation in the cells. Mitochondrial oxidation also fluctuated in the cells due to the high expression of miR-489. Notably, knockdown of miR-489 did not have a strong opposing effect on the cells. Periostin (Postn) was identified as a direct target gene for miR-489, and silencing the Postn gene similarly stimulated adipogenesis and differentiation of adipocytes.

SIGNIFICANCE

miR-489 provides a strong driving force for adipogenesis metabolism and adipocyte differentiation by targeting the Postn gene. This result may contribute to the treatment of obesity.

RNA-Seq Reveals Function of Bta-miR-149-5p in the Regulation of Bovine Adipocyte Differentiation

Intramuscular fat is a real challenge for the experts of animal science to improve meat quality traits. Research on the mechanism of adipogenesis provides invaluable information for the improvement of meat quality traits. This study investigated the effect of bta-miR-149-5p and its underlying mechanism on lipid metabolism in bovine adipocytes. Bovine adipocytes were differentiated and transfected with bta-miR-149-5p mimics or its negative control (NC). A total of 115 DEGs including 72 upregulated and 43 downregulated genes were identified in bovine adipocytes. The unigenes and GO term biological processes were the most annotated unigene contributor parts at 80.08%, followed by cellular component at 13.4% and molecular function at 6.7%. The KEGG pathways regulated by the DEGs were PI3K-Akt signaling pathway, calcium signaling pathway, pathways in cancer, MAPK signaling pathway, lipid metabolism/metabolic pathway, PPAR signaling pathway, AMPK signaling pathway, TGF-beta signaling pathway, cAMP signaling pathway, cholesterol metabolism, Wnt signaling pathway, and FoxO signaling pathway. In addition to this, the most important reactome enrichment pathways were R-BTA-373813 receptor CXCR2 binding ligands CXCL1 to 7, R-BTA-373791 receptor CXCR1 binding CXCL6 and CXCL8 ligands, R-BTA-210991 basigin interactions, R-BTA-380108 chemokine receptors binding chemokines, R-BTA-445704 calcium binding caldesmon, and R-BTA-5669034 TNFs binding their physiological receptors. Furthermore, the expression trend of the DEGs in these pathways were also exploited. Moreover, the bta-miR-149-5p significantly (p < 0.01) downregulated the mRNA levels of adipogenic marker genes such as CCND2, KLF6, ACSL1, Cdk2, SCD, SIK2, and ZEB1 in bovine adipocytes. In conclusion, our results suggest that bta-miR-149-5p regulates lipid metabolism in bovine adipocytes. The results of this study provide a basis for studying the function and molecular mechanism of the bta-miR-149-5p in regulating bovine adipogenesis.

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.

Bta-miR-376a Targeting KLF15 Interferes with Adipogenesis Signaling Pathway to Promote Differentiation of Qinchuan Beef Cattle Preadipocytes

Intramuscular fat (IMF) is a quality index associated with the taste and juiciness of meat. The deposition of IMF is affected by genetic and non-genetic factors, such as age, slaughter location, gender of the animal, and diet. Micro-ribonucleic acids (miRNA) are transcriptional regulators involved in adipogenesis, but the specific role of miR-376a in regulation of bovine adipocytes remains unknown. Our findings indicated that miR-376a was a potential negative regulator of bovine adipocyte differentiation. A bta-miR-376a mimic inhibited mRNA and protein expression of the marker genes, CDK1, CDK2, PCNA, C/EBPα, FAS, and PPAR γ, and significantly reduced ratios (%) of S-phase cells, the number of cells stained with 5-ethynyl-2'-deoxyuridine, and adipocyte proliferation. Oil red O staining and triglyceride content analysis also confirmed that bta-miR-376a was involved in adipocyte differentiation. Luciferase activities confirmed that Krüppel-like transcription factor 15 (KLF15) was a direct target gene of bta-miR-376a, and that KLF15 was a key transcription factor in adipogenesis. Therefore, bta-miR-376a might be a target for increasing beef IMF.