Identification and characterization of differentially expressed miRNAs in subcutaneous adipose between Wagyu and Holstein cattle

microRNA Temporal-Specific Expression Profiles Reveal longissimus dorsi Muscle Development in Tianzhu White Yak

As a class of regulatory factors, microRNAs (miRNAs) play an important role in regulating normal muscle development and fat deposition. Muscle and adipose tissues, as major components of the animal organism, are also economically important traits in livestock production. However, the effect of miRNA expression profiles on the development of muscle and adipose tissues in yak is currently unknown. In this study, we performed RNA sequencing (RNA-Seq) on Tianzhu white yak longissimus dorsi muscle tissue obtained from calves (6 months of age, M6, n = 6) and young (30 months of age, M30, n = 6) and adult yak (54 months of age, M54, n = 6) to identify which miRNAs are differentially expressed and to investigate their temporal expression profiles, establishing a regulatory network of miRNAs associated with the development of muscle and adipose. The results showed that 1191 miRNAs and 22061 mRNAs were screened across the three stages, of which the numbers of differentially expressed miRNAs (DE miRNAs) and differentially expressed mRNAs (DE mRNAs) were 225 and 450, respectively. The expression levels of the nine DE miRNAs were confirmed using a reverse transcription quantitative PCR (RT-qPCR) assay, and the trend of the assay results was generally consistent with the trend of the transcriptome profiles. Based on the expression trend, DE miRNAs were categorized into eight different expression patterns. Regarding the expression of DE miRNAs in sub-trends Profile 1 and Profile 2 (p < 0.05), the gene expression patterns were upregulated (87 DE miRNAs). Gene ontology (GO) and Kyoto Encyclopedia of Genes Genomes (KEGG) analyses showed that the identified DE miRNAs and DE mRNAs were enriched in pathway entries associated with muscle and intramuscular fat (IMF) growth and development. On this basis, we constructed a DE miRNA-mRNA interaction network. We found that some DE mRNAs of interest overlapped with miRNA target genes, such as ACSL3, FOXO3, FBXO30, FGFBP4, TSKU, MYH10 (muscle development), ACOX1, FADS2, EIF4E2, SCD1, EL0VL5, and ACACB (intramuscular fat deposition). These results provide a valuable resource for further studies on the molecular mechanisms of muscle tissue development in yak and also lay a foundation for investigating the interactions between genes and miRNAs.

A review of the role of epigenetic studies for intramuscular fat deposition in beef cattle

Intramuscular fat (IMF) deposition profoundly influences meat quality and economic value in beef cattle production. Meanwhile, contemporary developments in epigenetics have opened new outlooks for understanding the molecular basics of IMF regulation, and it has become a key area of research for world scholars. Therefore, the aim of this paper was to provide insight and synthesis into the intricate relationship between epigenetic mechanisms and IMF deposition in beef cattle. The methodology involves a thorough analysis of existing literature, including pertinent books, academic journals, and online resources, to provide a comprehensive overview of the role of epigenetic studies in IMF deposition in beef cattle. This review summarizes the contemporary studies in epigenetic mechanisms in IMF regulation, high-resolution epigenomic mapping, single-cell epigenomics, multi-omics integration, epigenome editing approaches, longitudinal studies in cattle growth, environmental epigenetics, machine learning in epigenetics, ethical and regulatory considerations, and translation to industry practices from perspectives of IMF deposition in beef cattle. Moreover, this paper highlights DNA methylation, histone modifications, acetylation, phosphorylation, ubiquitylation, non-coding RNAs, DNA hydroxymethylation, epigenetic readers, writers, and erasers, chromatin immunoprecipitation followed by sequencing, whole genome bisulfite sequencing, epigenome-wide association studies, and their profound impact on the expression of crucial genes governing adipogenesis and lipid metabolism. Nutrition and stress also have significant influences on epigenetic modifications and IMF deposition. The key findings underscore the pivotal role of epigenetic studies in understanding and enhancing IMF deposition in beef cattle, with implications for precision livestock farming and ethical livestock management. In conclusion, this review highlights the crucial significance of epigenetic pathways and environmental factors in affecting IMF deposition in beef cattle, providing insightful information for improving the economics and meat quality of cattle production.

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.

Milk-derived exosome nanovesicles: recent progress and daunting hurdles

Raw milk is the foundation of quality and safety in the dairy industry, and improving milk source management is the fundamental guarantee. Milk-derived exosomes (MDEs) are nanoscale information transfer molecules secreted by mammary cells with unique content and high stability, which can be used not only as potential markers to analyze key traits of lactation, reproduction, nutrition and health of animals, but also help farm managers to take timely interventions to improve animal welfare, milk quality, and functional traits. Our review first outlines the latest advances in MDEs isolation and purification, compositional analysis and characterization tools. We then provide a comprehensive summary of recent applications of MDEs liquid biopsy in breed selection, disease prevention and control, and feeding management. Finally, we evaluate the impact of processing on the stability of MDEs to offer guidance for dairy production and storage. The limitations and challenges in the development and use of MDEs markers are also discussed. As a noninvasive marker with high sensitivity and specificity, the MDEs-mediated assay technology is expected to be a powerful tool for measuring cow health and raw milk quality, enabling dynamic and precise regulation of dairy cows and full traceability of raw milk.

Overexpression of cholinergic receptor nicotinic gamma subunit inhibits proliferation and differentiation of bovine preadipocytes

OBJECTIVE

Muscle acetylcholine receptors have five alpha subunits (α, β, δ, ε, or γ), and cholinergic receptor nicotinic gamma subunit (CHRNG) is the γ subunit. It may also play an essential role in biological processes, including cell differentiation, growth, and survival, while the role of CHRNG has not been studied in the literature. Therefore, the purpose of this study is to clarify the effect of CHRNG on the proliferation and differentiation of bovine preadipocytes.

METHODS

We constructed a CHRNG overexpression adenovirus vector and successfully overexpressed it on bovine preadipocytes. The effects of CHRNG on bovine preadipocyte proliferation were detected by Edu assay, cell counting Kit-8 (CCK-8), real-time fluorescence quantitative polymerase chain reaction (RT-qPCR), Western blot and other techniques. We also performed oil red O, RT-qPCR, Western blot to explore its effect on the differentiation of preadipocytes.

RESULTS

The results of Edu proliferation experiments showed that the number of EDU-positive cells in the overexpression group was significantly less. CCK-8 experiments found that the optical density values of the cells in the overexpression group were lower than those of the control group, the mRNA levels of proliferating cell nuclear antigen (PCNA), cyclin A2 (CCNA2), cyclin B1 (CCNB1), cyclin D2 (CCND2) decreased significantly after CHRNG gene overexpression, the mRNA levels of cyclin dependent kinase inhibitor 1A (CDKN1A) increased significantly, and the protein levels of PCNA, CCNB1, CCND2 decreased significantly. Overexpression of CHRNG inhibited the differentiation of bovine preadipocytes. The results of oil red O and triglyceride determination showed that the size and speed of lipid droplets accumulation in the overexpression group were significantly lower. The mRNA and protein levels of peroxisome proliferator activated receptor gamma (PPARγ), CCAAT enhancer binding protein alpha (CEBPα), fatty acid binding protein 4 (FABP4), fatty acid synthase (FASN) decreased significantly.

CONCLUSION

Overexpression of CHRNG in bovine preadipocytes inhibits the proliferation and differentiation of bovine preadipocytes.

Differentiation and Maturation of Muscle and Fat Cells in Cultivated Seafood: Lessons from Developmental Biology

Cultivated meat, also known as cultured or cell-based meat, is meat produced directly from cultured animal cells rather than from a whole animal. Cultivated meat and seafood have been proposed as a means of mitigating the substantial harms associated with current production methods, including damage to the environment, antibiotic resistance, food security challenges, poor animal welfare, and-in the case of seafood-overfishing and ecological damage associated with fishing and aquaculture. Because biomedical tissue engineering research, from which cultivated meat draws a great deal of inspiration, has thus far been conducted almost exclusively in mammals, cultivated seafood suffers from a lack of established protocols for producing complex tissues in vitro. At the same time, fish such as the zebrafish Danio rerio have been widely used as model organisms in developmental biology. Therefore, many of the mechanisms and signaling pathways involved in the formation of muscle, fat, and other relevant tissue are relatively well understood for this species. The same processes are understood to a lesser degree in aquatic invertebrates. This review discusses the differentiation and maturation of meat-relevant cell types in aquatic species and makes recommendations for future research aimed at recapitulating these processes to produce cultivated fish and shellfish.

Excavation and characterization of key circRNAs for milk fat percentage in Holstein cattle

Milk fat percentage is one of the significant indicators governing the price and quality of milk and is regulated by a variety of non-coding RNAs. We used RNA sequencing (RNA-seq) techniques and bioinformatics approaches to explore potential candidate circular RNAs (circRNAs) regulating milk fat metabolism. After analysis, compared with low milk fat percentage (LMF) cows, 309 circRNAs were significantly differentially expressed in high milk fat percentage (HMF) cows. Functional enrichment and pathway analysis revealed that the main functions of the parental genes of differentially expressed circRNAs (DE-circRNAs) were related to lipid metabolism. We selected four circRNAs (Novel_circ_0000856, Novel_circ_0011157, novel_circ_0011944, and Novel_circ_0018279) derived from parental genes related to lipid metabolism as key candidate DE-circRNAs. Their head-to-tail splicing was demonstrated by linear RNase R digestion experiments and Sanger sequencing. However, the tissue expression profiles showed that only Novel_circ_0000856, Novel_circ_0011157, and Novel_circ_0011944 were expressed with high abundance in breast tissue. Based on the subcellular localization found that Novel_circ_0000856, Novel_circ_0011157, and Novel_circ_0011944 mainly function as competitive endogenous RNAs (ceRNAs) in the cytoplasm. Therefore, we constructed their ceRNA regulatory networks, and the five hub target genes (CSF1, TET2, VDR, CD34, and MECP2) in ceRNAs were obtained by CytoHubba and MCODE plugins in Cytoscape, as well as tissue expression profiles analysis of target genes. These genes play a key role as important target genes in lipid metabolism, energy metabolism, and cellular autophagy. The Novel_circ_0000856, Novel_circ_0011157, and Novel_circ_0011944 regulate the expression of hub target genes through interaction with miRNAs and constitute key regulatory networks that may be involved in milk fat metabolism. The circRNAs obtained in this study may act as miRNA sponges and thus influence mammary gland development and lipid metabolism in cows, which improves our understanding of the role of circRNAs in cow lactation.

Integrative Analysis of miRNAs Involved in Fat Deposition in Different Pig Breeds

BACKGROUND

miRNAs are a set of small, noncoding RNAs that bind to partially complementary sequences on target mRNAs. This leads to the post-transcriptional regulation of gene expression. Many studies have shown that microRNAs play critical roles in adipose cell differentiation and fat metabolism. The aim of this study was to explore the regulatory functions of miRNAs in fat deposition for the prevention and therapy of lipid metabolism-related diseases.

METHODS

The significant differences in the fat deposition of Laiwu (LW) pigs and Large White (LY) pigs were studied. To investigate the genetic relationships of miRNAs that regulate fat deposition, we performed a genome-wide analysis of miRNAs derived from subcutaneous adipose tissue of LW and LY pigs using RNA-seq.

RESULTS

There were 39 known miRNAs and 56 novel miRNAs significantly differential expressed between the two breeds of pigs. In the analysis of the Gene Ontology and KEGG pathways, predicted targets of these differentially expressed miRNAs were involved in several fat-associated pathways, such as the peroxisome proliferator-activated receptor (PPAR), mitogen-activated protein kinases (MAPK) and Wnt signaling pathways. In addition, ssc-miR-133a-3p, ssc-miR-486 and ssc-miR-1 each had a great impact on the development of porcine subcutaneous fat through the PPAR signaling pathway.

CONCLUSIONS

We explored the role of differentially expressed miRNAs and studied the mechanisms of adipogenesis and fat deposition between two different pig breeds. In addition, these results also contribute to research relevant to human obesity.

Identification of Differentially Expressed miRNAs in Porcine Adipose Tissues and Evaluation of Their Effects on Feed Efficiency

Feed efficiency (FE) is a very important trait affecting the economic benefits of pig breeding enterprises. Adipose tissue can modulate a variety of processes such as feed intake, energy metabolism and systemic physiological processes. However, the mechanism by which microRNAs (miRNAs) in adipose tissues regulate FE remains largely unknown. Therefore, this study aimed to screen potential miRNAs related to FE through miRNA sequencing. The miRNA profiles in porcine adipose tissues were obtained and 14 miRNAs were identified differentially expressed in adipose tissues of pigs with extreme differences in FE, of which 9 were down-regulated and 5 were up-regulated. GO and KEGG analyses indicated that these miRNAs were significantly related to lipid metabolism and these miRNAs modulated FE by regulating lipid metabolism. Subsequently, quantitative reverse transcription-polymerase chain reaction (qRT-PCR) of five randomly selected DEMs was used to verify the reliability of miRNA-seq data. Furthermore, 39 differentially expressed target genes of these DEMs were obtained, and DEMs-target mRNA interaction networks were constructed. In addition, the most significantly down-regulated miRNAs, ssc-miR-122-5p and ssc-miR-192, might be the key miRNAs for FE. Our results reveal the mechanism by which adipose miRNAs regulate feed efficiency in pigs. This study provides a theoretical basis for the further study of swine feed efficiency improvement.

Favored single nucleotide variants identified using whole genome Re-sequencing of Austrian and Chinese cattle breeds

Cattle have been essential for the development of human civilization since their first domestication few thousand years ago. Since then, they have spread across vast geographic areas following human activities. Throughout generations, the cattle genome has been shaped with detectable signals induced by various evolutionary processes, such as natural and human selection processes and demographic events. Identifying such signals, called selection signatures, is one of the primary goals of population genetics. Previous studies used various selection signature methods and normalized the outputs score using specific windows, in kbp or based on the number of SNPs, to identify the candidate regions. The recent method of iSAFE claimed for high accuracy in pinpointing the candidate SNPs. In this study, we analyzed whole-genome resequencing (WGS) data of ten individuals from Austrian Fleckvieh (Bos taurus) and fifty individuals from 14 Chinese indigenous breeds (Bos taurus, Bos taurus indicus, and admixed). Individual WGS reads were aligned to the cattle reference genome of ARS. UCD1.2 and subsequently undergone single nucleotide variants (SNVs) calling pipeline using GATK. Using these SNVs, we examined the population structure using principal component and admixture analysis. Then we refined selection signature candidates using the iSAFE program and compared it with the classical iHS approach. Additionally, we run Fst population differentiation from these two cattle groups. We found gradual changes of taurine in north China to admixed and indicine to the south. Based on the population structure and the number of individuals, we grouped samples to Fleckvieh, three Chinese taurines (Kazakh, Mongolian, Yanbian), admixed individuals (CHBI_Med), indicine individuals (CHBI_Low), and a combination of admixed and indicine (CHBI) for performing iSAFE and iHS tests. There were more significant SNVs identified using iSAFE than the iHS for the candidate of positive selection and more detectable signals in taurine than in indicine individuals. However, combining admixed and indicine individuals decreased the iSAFE signals. From both within-population tests, significant SNVs are linked to the olfactory receptors, production, reproduction, and temperament traits in taurine cattle, while heat and parasites tolerance in the admixed individuals. Fst test suggests similar patterns of population differentiation between Fleckvieh and three Chinese taurine breeds against CHBI. Nevertheless, there are genes shared only among the Chinese taurine, such as PAX5, affecting coat color, which might drive the differences between these yellowish coated breeds, and those in the greater Far East region.

Identification of potential miRNA-mRNA regulatory network and the key miRNAs in intramuscular and subcutaneous adipose

Intramuscular fat (IMF) is an important indicator for evaluating meat quality. Breeds with high IMF content are often accompanied by high subcutaneous fat (SCF), severely affecting the meat rate of pigs. Studying the mechanisms of miRNAs related to lipogenesis and lipid metabolism has important implications for pig breeding. We constructed two small RNA libraries from intramuscular and subcutaneous fat to evaluate the patterns of lipogenesis in Laiwu pig, a Chinese breed. A total of 286 differentially expressed miRNAs (DEmiRNAs), including 193 known miRNA and 93 novel miRNAs, were identified from two types of adipose. GO and KEGG enrichment analysis for DEmiRNAs showed that their target genes involved in many adipogenesis and lipid metabolism biological processes and signaling pathways, such as Wnt signaling pathway,MAPK signaling pathway, Hippo signaling pathway, PI3K-Akt signaling pathway, Melanogenesis, Signaling pathways regulating pluripotency of stem cells and so on. Then, we constructed a miRNA-mRNA interaction network to find out which miRNAs were the key miRNAs of regulation in Wnt signaling pathway. In this pathway, miR-331-3p, miR-339-5p, miR-874 and novel346_mature target PPARD, WNT10B, RSPO3, WNT2B. This study provides a theoretical basis for further understanding the post-transcriptional regulation mechanism of meat quality formation and predicting and treating diseases caused by ectopic fat.

Genome-Wide Analysis of microRNAs Identifies the Lipid Metabolism Pathway to Be a Defining Factor in Adipose Tissue From Different Sheep

microRNAs are a class of important non-coding RNAs, which can participate in the regulation of biological processes. In recent years, miRNA has been widely studied not only in humans and mice, but also in animal husbandry. However, compared with other livestock and poultry breeds, the study of miRNA in subcutaneous adipose tissue of sheep is not comprehensive. Transcriptome analysis of miRNAs in subcutaneous adipose tissue of Duolang sheep, and Small Tail Han sheep was performed using RNA-Seq technology. Differentially expressed miRNAs were screened between different breeds. Target genes were predicted, and then the joint analysis of candidate genes were conducted based on Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. Finally, the RNA-Seq data were verified by real-time quantitative polymerase chain reaction (qRT-PCR). Herein, we identified 38 differentially expressed miRNAs (9 novel miRNAs and 29 known miRNAs). In addition, a total of 854 target genes were predicted by miRanda software. GO and KEGG pathway analysis demonstrated that regulation of lipolysis in adipocytes plays a key role in the deposition of subcutaneous adipose tissue in Duolang sheep and Small Tail Han sheep. The miRNAs might regulate fat deposits by regulating genes involved in regulation of lipolysis in adipocytes. Specifically, NC_ 040278.1_ 37602, oar-mir-493-3p, NC_ 040278.1_ 37521 and NC_ 040255.1_ 11627 might target PTGS2, AKT2, AKT3, and PIK3CA, respectively, and then play critical regulatory role. In conclusion, all the results provide a good idea for further revealing the mechanism of subcutaneous adipose tissue deposition and improving the meat production performance of sheep, and lay a foundation for promoting the development of animal husbandry.

MiR-128-1-5p regulates differentiation of ovine stromal vascular fraction by targeting the KLF11 5'-UTR

Fat content is an important index to evaluate the individual performance of livestock animals such as sheep for meat production purposes. Reducing the subcutaneous and visceral fat while increasing the intramuscular fat is a valuable goal to achieve for the meat production industry. Here, we investigated the effect of miR-128-1-5p on adipogenesis of subcutaneous fat by targeting 5'-UTR in KLF11, a rare mechanism where most miRNAs bind the 3'-UTR of mRNAs. A dual fluorescence reporter assay was conducted to validate the binding sites of miR-128-1-5p on 5'-UTR of KLF11 mRNA. Roles of miR-128-1-5p in KLF11 expression were measured through co-transfecting miRNA mimics with KLF11-expressing vectors (CDSs together with or without the 5'-UTR) into ovine stromal vascular fractions (SVF). Additionally, functional roles of miR-128-1-5p, and KLF11 in adipogenesis of ovine subcutaneous fat were investigated. Results showed that miR-128-1-5p targeted KLF11 5'-UTR, reduced the fluorescence activity of the dual fluorescent reporter vector, as well as KLF11 mRNA, and protein expression levels. During the differentiation of SVF, disturbing the expression of miR-128-1-5p and KLF11 changed the adipogenic differentiation of SVF as observed in the lipid formation, and adipogenic marker genes. This study indicates that miR-128-1-5p promotes the expression of lipogenic marker genes and the formation of lipid droplets by targeting KLF11 5'-UTR. Furthermore, overexpression, and inhibition of KLF11 indicate that KLF11 inhibited SVF differentiation. In summary, the 5'-UTR binding mechanism discovered in this study extends the understanding of miRNA functions. Key roles of miR-128-1-5p and KLF11 in the adipogenesis of sheep subcutaneous fat have potential values for improving the meat and/or fat ratio of domestic animals.

Differential regulation of mRNAs and lncRNAs related to lipid metabolism in Duolang and Small Tail Han sheep

The function of long non-coding RNA (lncRNA) can be achieved through the regulation of target genes, and the deposition of fat is regulated by lncRNA. Fat has an important effect on meat quality. However, there are relatively few studies on lncRNAs in the subcutaneous adipose tissue of Duolang sheep and Small Tail Han sheep. In this study, RNA-Seq technology and bioinformatics methods were used to identify and analyze the lncRNA and mRNA in the subcutaneous adipose tissue of the two breeds of sheep. The results showed that 107 lnRNAs and 1329 mRNAs were differentially expressed. The differentially expressed genes and lncRNA target genes were significantly enriched in the biosynthesis of unsaturated fatty acids signaling pathway, fatty acid metabolism, adipocyte differentiation and other processes related to fat deposition. Among them, LOC105616076, LOC114118103, LOC105607837, LOC101116622, and LOC105603235 target FADS1, SCD, ELOVL6, HSD17B12 and HACD2, respectively. They play a key regulatory role in the biosynthesis of unsaturated fatty acids. This study lays a foundation for the study of the molecular mechanism of lncRNA on fat development, and has reference value for studying the differences in fat deposition between Duolang sheep and Small Tail Han sheep.

Integrating genomics and transcriptomics to identify candidate genes for subcutaneous fat deposition in beef cattle

Fat deposition is a complex economic trait regulated by polygenic genetic basis and environmental factors. Therefore, integrating multi-omics data to uncover its internal regulatory mechanism has attracted extensive attention. Here, we performed genomics and transcriptomics analysis to detect candidates affecting subcutaneous fat (SCF) deposition in beef cattle. The association of 770K SNPs with the backfat thickness captured nine significant SNPs within or near 11 genes. Additionally, 13 overlapping genes regarding fat deposition were determined via the analysis of differentially expressed genes and weighted gene co-expression network analysis (WGCNA). We then calculated the correlations of these genes with BFT and constructed their interaction network. Finally, seven biomarkers including ACACA, SCD, FASN, ACOX1, ELOVL5, HACD2, and HSD17B12 were screened. Notably, ACACA, identified by the integration of genomics and transcriptomics, was more likely to exert profound effects on SCF deposition. These findings provided novel insights into the regulation mechanism underlying bovine fat accumulation.

Integrated analysis of expression profiles with meat quality traits in cattle

MicroRNAs (miRNAs) play a vital role in improving meat quality by binding to messenger RNAs (mRNAs). We performed an integrated analysis of miRNA and mRNA expression profiling between bulls and steers based on the differences in meat quality traits. Fat and fatty acids are the major phenotypic indices of meat quality traits to estimate between-group variance. In the present study, 90 differentially expressed mRNAs (DEGs) and 18 differentially expressed miRNAs (DEMs) were identified. Eighty-three potential DEG targets and 18 DEMs were used to structure a negative interaction network, and 75 matching target genes were shown in this network. Twenty-six target genes were designated as intersection genes, screened from 18 DEMs, and overlapped with the DEGs. Seventeen of these genes enriched to 19 terms involved in lipid metabolism. Subsequently, 13 DEGs and nine DEMs were validated using quantitative real-time PCR, and seven critical genes were selected to explore the influence of fat and fatty acids through hub genes and predict functional association. A dual-luciferase reporter and Western blot assays confirmed a predicted miRNA target (bta-miR-409a and PLIN5). These findings provide substantial evidence for molecular genetic controls and interaction among genes in cattle.

miR-136 Suppresses the Aggressive Proliferation of Non-Small Cell Lung Cancer Through Restraining Histone Deacetylase 1 (HDAC1) and Phosphorylation of the Janus Kinase 2/Signal Transducer and Activator of Transcription 3 (Jak2/STAT3) Pathway

microRNA-136 can inhibit the proliferating activity of malignant cells and also participate in chemotherapy resistance of colorectal cancer via modulating HDAC1. This study assessed miR-136’s effect on NSCLC cell proliferation and underlying mechanisms. Tumor tissues and paracancerous tissues from NSCLC patients were collected to measure miR-136 and HDAC1 level. Cells were transfected with miR-136-mimics, miR-136-inhibitors or miR-136 mimics+HDAC1-OE followed by analysis of cell viability and apoptosis by CCK-8 method and flow cytometry, phosphorylation of Jak2/STAT3 by western blot. miR-136 was significantly downregulated in tumor tissues and NSCLC cells, accompanied by upregulated HDAC1. miR-136 overexpression suppressed HDAC1 expression, retarded phosphorylation and activation of Jak2/STAT3 signaling, reduced NSCLC cell viability and enhanced apoptosis. In addition, co-transfection of miR-136-mimics and HDAC1-OE reversed the inhibitory effects of miR-136 on NSCLC cells. In conclusion, miR-136 is reduced and HDAC1 is increased in NSCLC and miR-136 overexpression inhibited NSCLC cell proliferation and increased apoptosis possibly through regulating HDAC1/Jak2/STAT3 signal pathway, indicating that miR-136 might be a novel target for the treatment of NSCLC.

Breed dependent regulatory mechanisms of beneficial and non-beneficial fatty acid profiles in subcutaneous adipose tissue in cattle with divergent feed efficiency

The current study aimed to determine whether breed and feed efficiency affect the molecular mechanisms regulating beneficial and non-beneficial fatty acid profiles in subcutaneous adipose tissue of beef steers. Fatty acid profiling and RNA-Seq based transcriptome analysis were performed on subcutaneous adipose tissues collected from beef steers with three divergent breeds (Angus, ANG, n = 47; Charolais, CHAR, n = 48; Kinsella Composite, KC, n = 48) and different residual feed intake (RFI, a measure of feed efficiency). The comparison of fatty acid profiles showed that KC had higher beneficial FAs compared to the other two breeds. Distinct FA profiles between H-RFIfat and L-RFIfat steers was more obvious for KC steers, where H-RFIfat steers tended to have higher proportion of healthy FAs and lower proportion of the unhealthy FAs. A higher number of differentially expressed (DE) genes were observed for KC steers, whereas ANG and CHAR steers had a lower number of DE genes between H- and L-RFIfat steers. The association analyses of the gene expressions and FA profiles showed that 10 FA metabolism-associated genes together with the one upstream regulator (SREBF1) were associated with the proportion of C18:2n-6, total n-6, PUFA and PUFA/SFA for KC steers but not the other two breeds. Subcutaneous adipose tissue FA profiles and healthy FA index differed in cattle with divergent feed efficiency and such variation was unique for the three examined cattle breeds. Key FA metabolism-associated genes together with SREBF1 which is the upstream regulator of a set of genes involved in lipid metabolism may be of importance for genetic selection of meat with higher healthy FA index in beef cattle.

Increased expression of pro-inflammatory cytokines at the fetal-maternal interface in bovine pregnancies produced by cloning

PROBLEM

A significant rate of spontaneous abortion is observed in cattle pregnancies produced by somatic cell nuclear transfer (SCNT). Major histocompatibility complex class I (MHC-I) proteins are abnormally expressed on the surface of trophoblast cells from SCNT conceptuses.

METHOD OF STUDY

MHC-I homozygous compatible (n = 9), homozygous incompatible (n = 8), and heterozygous incompatible (n = 5) pregnancies were established by SCNT. Eight control pregnancies were established by artificial insemination. Uterine and trophoblast samples were collected on day 35 ±1 of pregnancy, the expression of immune-related genes was examined by qPCR, and the expression of trophoblast microRNAs was assessed by sequencing.

RESULTS

Compared to the control group, trophoblast from MHC-I heterozygous incompatible pregnancies expressed increased levels of CD28, CTLA4, CXCL8, IFNG, IL1A, IL2, IL10, IL12B, TBX21, and TNF, while GNLY expression was downregulated. The MHC-I homozygous incompatible treatment group expressed increased levels of IFNG, IL1A, and IL2 while the MHC-I homozygous compatible group did not differentially express any genes compared to the control group. In the endometrium, relative to the control group, MHC-I heterozygous incompatible pregnancies expressed increased levels of CD28, CTLA4, CXCL8, IFNG, IL10, IL12B, and TNF, while GATA3 expression was downregulated. The MHC-I homozygous incompatible group expressed decreased amounts of CSF2 transcripts compared with the control group but did not have abnormal expression of any other immune-related genes. MHC-I incompatible pregnancies had 40 deregulated miRNAs compared to control pregnancies and 62 deregulated microRNAs compared to MHC-I compatible pregnancies.

CONCLUSIONS

MHC-I compatibility between the dam and fetus prevented an exacerbated maternal immune response from being mounted against fetal antigens.

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.

Epigenomics analysis of miRNA cis-regulatory elements in pig muscle and fat tissues

Although large-scale and accurate identification of cis-regulatory elements on pig protein-coding and long non-coding genes has been reported, similar study on pig miRNAs is still lacking. Here, we systematically characterized the cis-regulatory elements of pig miRNAs in muscle and fat by adopting miRNAomes, ChIP-seq, ATAC-seq, RNA-seq and Hi-C data. In total, the cis-regulatory elements of 257 (85.95%) expressed miRNAs including 226 known and 31 novel miRNAs were identified. Especially, the miRNAs associated with super-enhancers, active promoters, and "A" compartment were significantly higher than those associated by typical enhancers, prompters without H3K27ac, and "B" compartment, respectively. The tissue specific transcription factors were the primary determination of core miRNA expression pattern in muscle and fat. Moreover, the miRNA promoters are more evolutionarily conserved than miRNA enhancers, like other type genes. Our study adds additional important information to existing pig epigenetic data and provides essential resource for future in-depth investigation of pig epigenetics.

Construction of Adipogenic ceRNA Network Based on lncRNA Expression Profile of Adipogenic Differentiation of Human MSC Cells

The Long non-coding RNA (lncRNA) expression profile data of ten samples including human Mesenchymal Stem Cell (MSC) adipogenic differentiation 0, 3, and 6 days from the GEO database, and then perform gene ID conversion, BLAST comparison, and annotation marking. Finally, group A (treatment group on day 3 of differentiation and control group on day 0 of differentiation) obtained a total of 1180 mRNA and 185 lncRNA; group B (treatment group on day 6 of differentiation and control group on day 0 of differentiation). A total of 1376 mRNA and 206 lncRNA were obtained. Finally, we processed the differential lncRNAs and mRNAs obtained in the two groups, and obtained 113 shared differential lncRNAs to further predict the targeted miRNA, a total of 815 lncRNA-miRNA pairs. The targeted mRNA was further predicted, and the grouped differential mRNAs were combined to obtain 64 differential mRNAs. In the end, we obtained 216 ceRNAs containing 26 lncRNAs, 27 miRNAs and 64 mRNAs. We found that the mRNAs in the ceRNA network were mainly enriched with 45 Gene Ontology (GO) terms, mainly including glucose homeostasis mechanism and insulin stimulation response. 69 Kyoto Encyclopedia of Genes and Genomes (KEGG) pathways were mainly enriched. It mainly includes many pathways related to lipid metabolism such as Adenosine 5'-monophosphate (AMP)-activated protein kinase (AMPK), Rap1, cAMP, mitogen-activated protein kinase (MAPK), Ras, hypoxia inducible factor-1 (HIF-1), PI3K-Akt, insulin signaling and so on. In the end, we identified 216 ceRNA regulatory relationships related to obesity research. Our research provides a clearer direction for understanding the molecular mechanism of obesity, the screening and determination of drug targets biomarkers in the future.

Integrated Genome-Wide Analysis of MicroRNA Expression Quantitative Trait Loci in Pig Longissimus Dorsi Muscle

Determining mechanisms regulating complex traits in pigs is essential to improve the production efficiency of this globally important protein source. MicroRNAs (miRNAs) are a class of non-coding RNAs known to post-transcriptionally regulate gene expression affecting numerous phenotypes, including those important to the pig industry. To facilitate a more comprehensive understanding of the regulatory mechanisms controlling growth, carcass composition, and meat quality phenotypes in pigs, we integrated miRNA and gene expression data from longissimus dorsi muscle samples with genotypic and phenotypic data from the same animals. We identified 23 miRNA expression Quantitative Trait Loci (miR-eQTL) at the genome-wide level and examined their potential effects on these important production phenotypes through miRNA target prediction, correlation, and colocalization analyses. One miR-eQTL miRNA, miR-874, has target genes that colocalize with phenotypic QTL for 12 production traits across the genome including backfat thickness, dressing percentage, muscle pH at 24 h post-mortem, and cook yield. The results of our study reveal genomic regions underlying variation in miRNA expression and identify miRNAs and genes for future validation of their regulatory effects on traits of economic importance to the global pig industry.

Multi-Omics Approach Reveals miR-SNPs Affecting Muscle Fatty Acids Profile in Nelore Cattle

MicroRNAs (miRNAs) are key regulators of gene expression, potentially affecting several biological processes, whose function can be altered by sequence variation. Hence, the integration of single nucleotide polymorphisms (SNP) and miRNAs can explain individual differences in economic traits. To provide new insights into the effects of SNPs on miRNAs and their related target genes, we carried out a multi-omic analysis to identify SNPs in miRNA mature sequences (miR-SNPs) associated with fatty acid (FA) composition in the Nelore cattle. As a result, we identified 3 miR-SNPs in different miRNAs (bta-miR-2419-3p, bta-miR-193a-2, and bta-miR-1291) significantly associated with FA traits (p-value < 0.02, Bonferroni corrected). Among these, the rs110817643C>T, located in the seed sequence of the bta-miR-1291, was associated with different ω6 FAs, polyunsaturated FA, and polyunsaturated:saturated FA ratios. Concerning the other two miR-SNPs, the rs43400521T>C (located in the bta-miR-2419-3p) was associated with C12:0 and C18:1 cis-11 FA, whereas the rs516857374A>G (located in the bta-miR-193a-2) was associated with C18:3 ω6 and ratio of ω6/ω3 traits. Additionally, to identify potential biomarkers for FA composition, we described target genes affected by these miR-SNPs at the mRNA or protein level. Our multi-omics analysis outlines the effects of genetic polymorphism on miRNA, and it highlights miR-SNPs and target candidate genes that control beef fatty acid composition.

Differential expression of miRNAs in skeletal muscles of Indian sheep with diverse carcass and muscle traits

The study presents the miRNA profiles of two Indian sheep populations with divergent carcass and muscle traits. The RNA sequencing of longissimus thoracis muscles from the two populations revealed a total of 400 known miRNAs. Myomirs or miRNAs specific to skeletal muscles identified in our data included oar-miR-1, oar-miR-133b, oar-miR-206 and oar-miR-486. Comparison of the two populations led to identification of 100 differentially expressed miRNAs (p < 0.05). A total of 45 miRNAs exhibited a log₂ fold change of ≥ ( ±) 3.0. Gene Ontology analysis revealed cell proliferation, epithelial to mesenchymal transition, apoptosis, immune response and cell differentiation as the most significant functions of the differentially expressed miRNAs. The differential expression of some miRNAs was validated by qRT-PCR analysis. Enriched pathways included metabolism of proteins and lipids, PI3K-Akt, EGFR and cellular response to stress. The microRNA-gene interaction network revealed miR-21, miR-155, miR-143, miR-221 and miR-23a as the nodal miRNAs, with multiple targets. MicroRNA-21 formed the focal point of the network with 42 interactions. The hub miRNAs identified in our study form putative regulatory candidates for future research on meat quality traits in Indian sheep. Our results provide insight into the biological pathways and regulatory molecules implicated in muscling traits of sheep.

Functions of Circular RNAs in Regulating Adipogenesis of Mesenchymal Stem Cells

The mesenchymal stem cells (MSCs) are known as highly plastic stem cells and can differentiate into specialized tissues such as adipose tissue, osseous tissue, muscle tissue, and nervous tissue. The differentiation of mesenchymal stem cells is very important in regenerative medicine. Their differentiation process is regulated by signaling pathways of epigenetic, transcriptional, and posttranscriptional levels. Circular RNA (circRNA), a class of noncoding RNAs generated from protein-coding genes, plays a pivotal regulatory role in many biological processes. Accumulated studies have demonstrated that several circRNAs participate in the cell differentiation process of mesenchymal stem cells in vitro and in vivo. In the current review, characteristics and functions of circRNAs in stem cell differentiation will be discussed. The mechanism and key role of circRNAs in regulating mesenchymal stem cell differentiation, especially adipogenesis, will be reviewed and discussed. Understanding the roles of these circRNAs will present us with a more comprehensive signal path network of modulating stem cell differentiation and help us discover potential biomarkers and therapeutic targets in clinic.

Differentially Expressed miRNA-Gene Targets Related to Intramuscular Fat in Musculus Longissimus Dorsi of Charolais × Holstein F2-Crossbred Bulls

Intramuscular fat (IMF) is a meat quality indicator associated with taste and juiciness. IMF deposition, influenced by genetic and non-genetic factors, occurs through a transcriptionally coordinated process of adipogenesis. MicroRNAs (miRNAs) are transcriptional regulators of vital biological processes, including lipid metabolism and adipogenesis. However, in bovines, limited data on miRNA profiling and association with divergent intramuscular fat content, regulated exclusively by genetic parameters, have been reported. Here, a microarray experiment was performed to identify and characterize the miRNA expression pattern in the Musculus longissimus dorsi of F₂-cross (Charolais × German Holstein) bulls with high and low IMF. A total of 38 differentially expressed miRNAs (DE miRNAs), including 33 upregulated and 5 downregulated (corrected p-value ≤ 0.05, FC ≥ ±1.2), were reported. Among DE miRNAs, the upregulated miRNAs miR-105a/b, miR-695, miR-1193, miR-1284, miR-1287-5p, miR-3128, miR-3178, miR-3910, miR-4443, miR-4445 and miR-4745, and the downregulated miRNAs miR-877-5p, miR-4487 and miR-4706 were identified as novel fat deposition regulators. DE miRNAs were further analyzed, along with previously identified differentially expressed genes (DEGs) from the same samples and predicted target genes, using multiple bioinformatic approaches, including target prediction tools and co-expression networks, as well as Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) enrichment. We identified DE miRNAs and their gene targets associated with bovine intramuscular adipogenesis, and we provide a basis for further functional investigations.

RNA-Seq analysis reveals the potential molecular mechanisms of daidzein on adipogenesis in subcutaneous adipose tissue of finishing Xianan beef cattle

Daidzein has been reported to be effective in regulating lipid metabolism in animals. However, the molecular mechanisms of daidzein on adipogenesis in beef cattle are not yet reported and the results of daidzein on affecting lipid metabolism in other species have been conflicting. High-throughput sequencing of mRNA (RNA-Seq) technology was performed to elucidate the underlying molecular mechanisms of daidzein on adipogenesis in subcutaneous adipose tissue of finishing Xianan beef cattle. A total of 893 differentially expressed genes (DEGs) were identified by differential expression analysis, among which 405 genes were upregulated and 488 genes were downregulated. Bioinformatics analysis suggested that these DEGs were significantly enriched to the pathways related to lipid metabolism including ECM-receptor interaction, Glycolysis/Gluconeogenesis and Hedgehog signalling pathway. Daidzein significantly affected the candidate genes (Shh, Pec, Gli, Wnt6, DLK, IGFBP2, ID3 and C/EBPE) related to adipocyte differentiation. Besides, daidzein improved the ability of subcutaneous adipocytes in synthesizing triglycerides by directly using the long-chain fatty acids and enhanced the efficiency of triglyceride synthesis of subcutaneous adipocytes in Xianan steers. In conclusion, daidzein plays a positive role not only in adipogenic differentiation, but also in triglyceride synthesis in subcutaneous adipose tissue of Xianan beef cattle.

Comparative analysis of bovine maternal corpus luteum microRNAs with aberrant and normal developed cloned fetus at late gestation

BACKGROUND

The development efficiency of cloned cattle is extremely low (< 5%), most of them were aborted at late gestation. Based on our previous studies, some recipient cows with a cloned fetus would present as engorged uterine vessels and enlarged umbilical vessels randomly. Abortion involves both maternal and fetal factors.

OBJECTIVE

Our aim was to explore this phenomenon by microRNAs expression profile analysis of maternal corpus luteum (CL), which was related to pregnancy maintenance.

METHODS

The present study provided the comparison of maternal CL miRNAs expression of abnormally and normally developed cloned bovine fetus at late gestation (~ 210 days) using RNA-Seq technology.

RESULTS

We selected two abnormally pregnant cows (abnormal group, AG) and three normally pregnant cows (normal group, NG) and acquired valid reads of 9317,261-12,327,185 (~ 84.53-91.28%) from five libraries. In total, we identified 981 conserved miRNAs and 223 novel miRNAs. 1052 miRNAs were co-expressed, 124 miRNAs were uniquely expressed in AG, and 93 miRNAs were uniquely expressed in the NG. Compared with NG, 11 were significantly overexpressed, and 22 were downregulated (p < 0.05) at AG among 1052 co-expressed miRNAs. The differentially expressed miRNAs-targeted genes were further analyzed by Gene Ontology and KEGG pathway analysis. Notably, the steroid biosynthesis pathway was a significantly enriched term (p < 0.01), which may affect the secretion of progesterone.

CONCLUSION

Our research suggested that abnormal miRNAs expression of bovine maternal CL may affect the pregnant status at late gestation.

Neudesin Neurotrophic Factor Promotes Bovine Preadipocyte Differentiation and Inhibits Myoblast Myogenesis

Simple Summary

Neudesin neurotrophic factor (NENF) is a secreted protein that was significantly inhibited in the fat-muscle co-culture system in our previous study. However, studies on NENF regulation of bovine muscle development and involvement in the cross-talk between adipose tissue and skeletal muscle have not been reported. Hence, the aim of this study was to clarify the roles of NENF in bovine myoblast and preadipocyte differentiation. In this study, we first examined the spatial expression patterns of NENF in different tissues and found that NENF was highly expressed in the muscle of four-day-old and 24-month-old Qinchuan cattle. Compared with 4-day-old Qinchuan cattle, the expression level of NENF was significantly up-regulated in 24-month-old bovine adipose tissue. Then, we detected the expression pattern of the NENF gene in bovine preadipocyte and myoblast differentiation and found that the expression of NENF mRNA peaks at day 6 during preadipocyte differentiation and peaks at day 4 during myoblast differentiation. Furthermore, we found that the endogenous knockdown of NENF inhibited the differentiation of preadipocytes and promoted the differentiation of myoblasts. These findings not only lay the foundation for the construction of regulatory pathways during fat and muscle differentiation but also provide a theoretical basis for molecular breeding of beef cattle.

Abstract

Neudesin neurotrophic factor (NENF) is a secreted protein that is essential in multiple biological processes, including neural functions, adipogenesis, and tumorigenesis. In our previous study, NENF was significantly inhibited in the bovine adipocytes-myoblasts co-culture system. However, studies on NENF regulation of bovine muscle development and involvement in the cross-talk between adipose tissue and skeletal muscle have not been reported. Hence, the aim of this study was to clarify the functional roles of NENF in bovine preadipocytes and myoblasts. Real-time quantitative PCR (RT-qPCR) was performed to examine the spatial expression patterns of NENF in different tissues, and the results showed that NENF was highly expressed in the muscle of four-day-old and 24-month-old Qinchuan cattle. Compared with four-day-old Qinchuan cattle, the expression level of NENF was significantly up-regulated in 24-month-old bovine adipose tissue. To explore the roles of NENF in bovine myoblast and preadipocyte differentiation, small interfering RNA (siRNA) targeting the NENF gene were transfected into bovine preadipocytes and myoblasts to knock down the expression of the NENF gene. The results showed that the knockdown of NENF in differentiating adipocytes attenuated lipid accumulation, decreased the mRNA expression of adipogenic key marker genes PPARγ, CEBPα, CEBPβ, FASN, and SCD1, and decreased the protein expression of PPARγ, CEBPα, and FASN. The formation of myotubes was significantly accelerated, and the mRNA expression levels of myogenic marker genes MYOD1, MYF5, MYF6, MEF2A, MEF2C, and CKM, and the protein expression levels of MYOD1, MYF6, MEF2A, and CKM were up-regulated in myoblasts where NENF was knocked down. In short, the knockdown of NENF inhibited preadipocyte differentiation and promoted myoblast myogenesis.

High-Throughput RNA Sequencing Reveals NDUFC2-AS lncRNA Promotes Adipogenic Differentiation in Chinese Buffalo (Bubalus bubalis L)

The buffalo (Bubalus bubalis L.) is prevalent in China and the increasing demand for meat production has changed its role from being a beast of burden to a meat source. The low fat deposition level has become one of the main barriers for its use in meat production. It is urgent to reveal factors involved in fat deposition in buffalo. This study performed RNA sequencing to investigate both long noncoding RNAs (lncRNAs) and mRNAs of adipose tissues in young and adult buffalos. A total of 124 lncRNAs and 2008 mRNAs showed differential expression patterns between young and adult samples. Coexpression analysis and functional enrichment revealed 585 mRNA–lncRNA pairs with potential function in fat deposition. After validation by qRT-PCR, we focused on a lncRNA transcribed from the ubiquinone oxidoreductase subunit C2 (NDUFC2) antisense (AS) strand which showed high correlation with thyroid hormone responsive protein (THRSP). NDUFC2-AS lncRNA is highly expressed in adipose tissue and maturation adipocytes and mainly exists in the nucleus. Functional assays demonstrated that NDUFC2-AS lncRNA promotes adipogenic differentiation by upregulating the expression levels of THRSP and CCAAT enhancer binding protein alpha (C/EBPα) in buffalo. These results indicate that NDUFC2-AS lncRNA promotes fat deposition in buffalo.

Co-Expression Networks Reveal Potential Regulatory Roles of miRNAs in Fatty Acid Composition of Nelore Cattle

Fatty acid (FA) content affects the sensorial and nutritional value of meat and plays a significant role in biological processes such as adipogenesis and immune response. It is well known that, in beef, the main FAs associated with these biological processes are oleic acid (C18:1 cis9, OA) and conjugated linoleic acid (CLA-c9t11), which may have beneficial effects on metabolic diseases such as type 2 diabetes and obesity. Here, we performed differential expression and co-expression analyses, weighted gene co-expression network analysis (WGCNA) and partial correlation with information theory (PCIT), to uncover the complex interactions between miRNAs and mRNAs expressed in skeletal muscle associated with FA content. miRNA and mRNA expression data were obtained from skeletal muscle of Nelore cattle that had extreme genomic breeding values for OA and CLA. Insulin and MAPK signaling pathways were identified by WGCNA as central pathways associated with both of these fatty acids. Co-expression network analysis identified bta-miR-33a/b, bta-miR-100, bta-miR-204, bta-miR-365-5p, bta-miR-660, bta-miR-411a, bta-miR-136, bta-miR-30-5p, bta-miR-146b, bta-let-7a-5p, bta-let-7f, bta-let-7, bta-miR 339, bta-miR-10b, bta-miR 486, and the genes ACTA1 and ALDOA as potential regulators of fatty acid synthesis. This study provides evidence and insights into the molecular mechanisms and potential target genes involved in fatty acid content differences in Nelore beef cattle, revealing new candidate pathways of phenotype modulation that could positively benefit beef production and human consumption.

Comprehensive Analysis of Differentially Expressed mRNA, lncRNA and circRNA and Their ceRNA Networks in the Longissimus Dorsi Muscle of Two Different Pig Breeds

Circular RNA (circRNA) and long non-coding RNA (lncRNA) are known to participate in adipogenesis and myogenic differentiation, but their impact on porcine muscle traits is not well understood. We compared their expressional profiles in the longissimus dorsi muscle of Chinese Huainan pigs (HN, the fat type) and Western commercial Duroc×(Landrace×Yorkshire) (DLY, the thin type) pigs, and 854 mRNAs, 233 lncRNAs, and 66 circRNAs (p < 0.05 and ｜log₂FoldChange｜>1) were found to be differentially expressed. The differentially expressed mRNA and circRNA parental genes were enriched in the Wnt signaling pathway (adipogenesis), the transition between fast and slow fibers (myogenic differentiation), and alanine, aspartate and glutamate metabolism (pork flavor). The potential lncRNAs/circRNAs-miRNAs-mRNAs regulatory networks shared MYOD1, PPARD, miR-423-5p and miR-874, which were associated with skeletal muscle muscular proliferation, differentiation/regeneration and adipogenesis. Taken together, these differentially expressed non-coding RNAs may be involved in the molecular basis of muscle traits, acting as the competing endogenous RNA (ceRNA) for miRNAs.

Autozygosity islands and ROH patterns in Nellore lineages: evidence of selection for functionally important traits

Background

The aim of this study was to assess genome-wide autozygosity in a Nellore cattle population and to characterize ROH patterns and autozygosity islands that may have occurred due to selection within its lineages. It attempts also to compare estimates of inbreeding calculated from ROH (F_ROH), genomic relationship matrix (F_GRM), and pedigree-based coefficient (F_PED).

Results

The average number of ROH per animal was 55.15 ± 13.01 with an average size of 3.24 Mb. The Nellore genome is composed mostly by a high number of shorter segments accounting for 78% of all ROH, although the proportion of the genome covered by them was relatively small. The genome autozygosity proportion indicates moderate to high inbreeding levels for classical standards, with an average value of 7.15% (178.70 Mb). The average of F_PED and F_ROH, and their correlations (− 0.05 to 0.26) were low. Estimates of correlation between F_GRM-F_PED was zero, while the correlation (− 0.01 to − 0.07) between F_GRM-F_ROH decreased as a function of ROH length, except for F_{ROH > 8Mb} (− 0.03). Overall, inbreeding coefficients were not high for the genotyped animals. Autozygosity islands were evident across the genome (n = 62) and their genomic location did not largely differ within lineages. Enriched terms (p < 0.01) associated with defense response to bacteria (GO:0042742), immune complex reaction (GO:0045647), pregnancy-associated glycoproteins genes (GO:0030163), and organism growth (GO:0040014) were described within the autozygotic islands.

Conclusions

Low F_PED-F_ROH correlation estimates indicate that F_PED is not the most suitable method for capturing ancient inbreeding when the pedigree does not extend back many generations and F_ROH should be used instead. Enriched terms (p < 0.01) suggest a strong selection for immune response. Non-overlapping islands within the lineages greatly explain the mechanism underlying selection for functionally important traits in Nellore cattle.

Electronic supplementary material

The online version of this article (10.1186/s12864-018-5060-8) contains supplementary material, which is available to authorized users.

MiR-27a-5p Increases Steer Fat Deposition Partly by Targeting Calcium-sensing Receptor (CASR)

Castration increases fat deposition, improving beef quality in cattle. Here, the steer group exhibited a significantly higher intramuscular fat (IMF) content than the bull group. To determine the potential roles of microRNAs (miRNAs) in castration-induced fat deposition, differential expression patterns of miRNA in liver tissue were investigated in bulls and steers. A total of 7,827,294 clean reads were obtained from the bull liver library, and 8,312,483 were obtained from the steer liver library; 452 conserved bovine miRNAs and 20 novel miRNAs were identified. The results showed that the expression profiles of miRNA in liver tissue were changed by castration, and 12 miRNAs that were differentially expressed between bulls and steers were identified. Their target genes were majorly involved in the metabolic, PI3K-Akt, and MAPK signaling pathways. Furthermore, six differentially expressed miRNAs were validated by quantitative real-time PCR, and luciferase reporter assays verified that calcium-sensing receptor (CASR) was the direct target of miR-27a-5p. Meantime, we found that the expression level of CASR was significantly higher in steers than in bulls, and revealed that CASR gene silencing in bovine hepatocytes significantly inhibited triacylglycerol (TAG) accumulation and reduced secretion of very low density lipoprotein (VLDL). These results obtained in the liver indicate that miR-27a-5p may increase fat deposition partly by targeting CASR in steers.

MiR-152 Regulates Apoptosis and Triglyceride Production in MECs via Targeting ACAA2 and HSD17B12 Genes

Mammary epithelial cells (MECs) affect milk production capacity during lactation and are critical for the maintenance of tissue homeostasis. Our previous studies have revealed that the expression of miR-152 was increased significantly in MECs of cows with high milk production. In the present study, bioinformatics analysis identified ACAA2 and HSD17B12 as the potential targets of miR-152, which were further validated by dual-luciferase repoter assay. In addition, the expressions of miR-152 was shown to be negatively correlated with levels of mRNA and protein of ACAA2, HSD17B12 genes by qPCR and western bot analysis. Furthermore, transfection with miR-152 significantly up-regulated triglyceride production, promoted proliferation and inhibited apoptosis in MECs. Furthermore, overexpression of ACAA2 and HSD17B12 could inhibit triglyceride production, cells proliferation and induce apoptosis; but sh234-ACAA2-181/sh234-HSD17B12-474 could reverse the trend. These findings suggested that miR-152 could significantly influence triglyceride production and suppress apoptosis, possibly via the expression of target genes ACAA2 and HSD17B12.

An Integrated Analysis of miRNAs and Methylated Genes Encoding mRNAs and lncRNAs in Sheep Breeds with Different Fecundity

In our previous study, we investigated the regulatory relationship between lncRNAs, miRNA, and mRNAs in an effort to shed light onto the regulatory mechanisms involved in sheep fecundity. As an extension of this study, here, we aimed to identify potential regulators of sheep fecundity using a genome-wide analysis of miRNAs and the methylated genes encoding mRNAs and lncRNAs in the ovaries of Dorset sheep (low fecundity) and Small Tail Han ewes (high fecundity) with the genotype BB (Han BB) and the genotype ++ (Han ++) by performing RNA-Seq and MeDIP-Seq analyses. Methylated coding-non-coding gene co-expression networks for Han and Dorset sheep were constructed using the methylated genes encoding the differentially expressed mRNAs and lncRNAs identified in this study. In the Han BB vs. Dorset comparison, the lncRNAs TTC26 and MYH15 had the largest degree. Similarly, the lncRNA NYAP1 had the largest degree in the Han ++ vs. Dorset comparison. None of the methylated genes encoding lncRNAs were co-expressed with the methylated genes encoding mRNAs in the Han BB vs. Han ++ comparison. The methylated genes encoding lncRNAs identified here may play a vital regulatory role in sheep breeding. Our results suggest that miRNAs might play a key role in sheep prolificacy by regulating target genes related to thyroid hormone synthesis, and methylated genes encoding lncRNAs associated with tight junctions might contribute to the high breeding rate in Han sheep. These findings may contribute to a deeper understanding of sheep prolificacy.

Melatonin promotes triacylglycerol accumulation via MT2 receptor during differentiation in bovine intramuscular preadipocytes

Melatonin (N-acetyl-5-methoxytryptamine) is a derivative of tryptophan which is produced and secreted mainly by the pineal gland and regulates a variety of important central and peripheral actions. To examine the potential effects of melatonin on the proliferation and differentiation of bovine intramuscular preadipocytes (BIPs), BIPs were incubated with different concentrations of melatonin. Melatonin supplementation at 1 mM significantly increased peroxisome proliferator-activated receptor γ (PPARγ), CCAAT/enhancer-binding protein (C/EBP) β, and C/EBPα expression and promoted the differentiation of BIPs into adipocytes with large lipid droplets and high cellular triacylglycerol (TAG) levels. Melatonin also significantly enhanced lipolysis and up-regulated the expression of lipolytic genes and proteins, including hormone sensitive lipase (HSL), adipocyte triglyceride lipase (ATGL), and perilipin 1 (PLIN1). Moreover, melatonin reduced intracellular reactive oxygen species (ROS) levels by increasing the expression levels and activities of superoxide dismutase 1 (SOD1) and glutathione peroxidase 4 (GPX4). Finally, the positive effects of melatonin on adipogenesis, lipolysis, and redox status were reversed by treatment with luzindole, anantagonist of nonspecific melatonin receptors 1 (MT1) and 2 (MT2), and 4-phenyl-2-propionamidotetraline (4P-PDOT), a selective MT2 antagonist. These results reveal that melatonin promotes TAG accumulation via MT2 receptor during differentiation in BIPs.

Screening of miRNA profiles and construction of regulation networks in early and late lactation of dairy goat mammary glands

In recent years, studies related to the expression profiles of miRNAs in the dairy goat mammary gland were performed, but regulatory mechanisms in the physiological environment and the dynamic homeostasis of mammary gland development and lactation are not clear. In the present study, sequencing data analysis of early and late lactation uncovered a total of 1,487 unique miRNAs, including 45 novel miRNA candidates and 1,442 known and conserved miRNAs, of which 758 miRNAs were co-expressed and 378 differentially expressed with P < 0.05. Moreover, 76 non-redundant target genes were annotated in 347 GO consortiums, with 3,143 candidate target genes grouped into 33 pathways. Additionally, 18 predicted target genes of 214 miRNAs were directly annotated in mammary gland development and used to construct regulatory networks based on GO annotation and the KEGG pathway. The expression levels of seven known miRNAs and three novel miRNAs were examined using quantitative real-time PCR. The results showed that miRNAs might play important roles in early and late lactation during dairy goat mammary gland development, which will be helpful to obtain a better understanding of the genetic control of mammary gland lactation and development.

Global transcriptome analysis identifies differentially expressed genes related to lipid metabolism in Wagyu and Holstein cattle

Fat deposition of beef cattle varies between breeds. However, the regulation mechanism is still not elucidated completely at molecular level. In the present study, we comparatively analyzed transcriptome of subcutaneous adipose tissue between Wagyu and Holstein cattle with a significant difference in fat deposition to identify key genes associated with fat metabolism and adipogenesis by high-throughput RNA-seq technology. A total of 59,149,852 and 69,947,982 high quality reads were generated, respectively. With further analysis, 662 differentially expressed genes were identified. Gene Ontology and KEGG pathway analysis revealed that many differentially expressed genes were enriched in several biological processes and pathways relevant to adipogenesis and lipid metabolism, in which PPAR and fatty acid metabolism signaling pathways with related genes such as PPARγ, PLIN2 and ELOVL6 et al. play a critical role. Protein-protein interaction network analysis showed EGR1, FOS, SERPINE1, AGT, MMP2 may have great impact on adipocyte differentiation and adipogenesis. Moreover, potential alternative splicing events and single nucleotide polymorphisms (SNPs) were also identified. In summary, we comprehensively analyzed and discussed the transcriptome of subcutaneous adipose tissue of Wagyu and Holstein cattle, which might provide a theoretical basis for better understanding molecular mechanism of fat metabolism and deposition in beef cattle.