Deep Small RNA Sequencing Reveals Important miRNAs Related to Muscle Development and Intramuscular Fat Deposition in Longissimus dorsi Muscle From Different Goat Breeds

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.

Expression patterns of housekeeping genes and tissue-specific genes in black goats across multiple tissues

Black goats are a significant meat breed in southern China. To investigate the expression patterns and biological functions of genes in various tissues of black goats, we analyzed housekeeping genes (HKGs), tissue-specific genes (TSGs), and hub genes (HUBGs) across 23 tissues. Additionally, we analyzed HKGs in 13 tissues under different feeding conditions. We identified 2968 HKGs, including six important ones. Interestingly, HKGs in grazing black goats demonstrated higher and more stable expression levels. We discovered a total of 9912 TSGs, including 134 newly identified ones. The number of TSGs for mRNA and lncRNA were nearly equal, with 127 mRNA TSGs expressed solely in one tissue. Additionally, the predicted functions of tissue-specific long non-coding RNAs (lncRNAs) targeting mRNAs corresponded with the physiological functions of the tissues.Weighted gene co-expression network analysis (WGCNA) constructed 30 modules, where the dark grey module consists almost entirely of HKGs, and TSGs are located in modules most correlated with their respective tissues. Additionally, we identified 289 HUBGs, which are involved in regulating the physiological functions of their respective tissues. Overall, these identified HKGs, TSGs, and HUBGs provide a foundation for studying the molecular mechanisms affecting the genetic and biological processes of complex traits in black goats.

MicroRNA expression profiles reveal wool development and fineness regulation in Gansu alpine fine-wool sheep

The development of wool has a complex regulatory mechanism both influenced by genetic and environmental factors. MicroRNAs (miRNA) were involved in various biological processes of animals, and may play an important role in the regulation of wool development. In this study, we comprehensively analyzed and identified the histological parameters of hair follicles, as well as the miRNAs, target genes, pathways, and Gene Ontology terms related to wool fineness regulation and wool growth and development using HE staining and RNA-Seqs methods. Both coarse (group C, mean fiber diameter (MFD) = 22.26 ± 0.69 μm, n = 6) and fine (group F, MFD = 16.91 ± 0.29 μm, n = 6) of Gansu alpine fine-wool sheep with different wool fineness were used in this study. The results showed that the primary follicle diameter and secondary wool fiber diameter in group C were significantly higher than those in group F (P < 0.05). And the number of primary and secondary hair follicles in group C was significantly lower than that in group F (P < 0.05). Furthermore, a total of 67 DE miRNAs and 290 potential DE miRNAs target genes were screened in the skin tissues of sheep from groups F and C, and some potential target genes related to wool fineness regulation were screened, such as CDH2, KRT82, FOXN1, LOC101106296, KRT20, MCOLN3, KRT71, and TERT. These genes were closely related to Glutathione metabolism, epidermal cell differentiation, keratinization, and regulation of hair cycle. Moreover, the regulatory network of miRNAs-mRNAs suggested that miRNAs (miR-129-x, novel m0079-3p, miR-2484-z, novel m0025-5P, etc.) may play a key role in the wool development and wool fineness regulation of Gansu alpine fine-wool sheep. In summary, this study expands the existing miRNAs database and provides new information for studying the regulation of wool development in Gansu alpine fine wool sheep.

Comprehensive Atlas of Alternative Splicing Reveals NSRP1 Promoting Adipogenesis through CCDC18

Alternative splicing (AS) plays a crucial role in regulating gene expression, function, and diversity. However, limited reports exist on the identification and comparison of AS in Eastern and Western pigs. Here, we analyzed 243 transcriptome data from eight tissues, integrating information on transcription factors (TFs), selection signals, splicing factors (SFs), and quantitative trait loci (QTL) to comprehensively study alternative splicing events (ASEs) in pigs. Five ASE types were identified, with Mutually Exclusive Exon (MXE) and Skipped Exon (SE) ASEs being the most prevalent. A significant portion of genes with ASEs (ASGs) showed conservation across all eight tissues (63.21-76.13% per tissue). Differentially alternative splicing genes (DASGs) and differentially expressed genes (DEGs) exhibited tissue specificity, with blood and adipose tissues having more DASGs. Functional enrichment analysis revealed coDASG_DEGs in adipose were enriched in pathways associated with adipose deposition and immune inflammation, while coDASG_DEGs in blood were enriched in pathways related to immune inflammation and metabolism. Adipose deposition in Eastern pigs might be linked to the down-regulation of immune-inflammation-related pathways and reduced insulin resistance. The TFs, selection signals, and SFs appeared to regulate ASEs. Notably, ARID4A (TF), NSRP1 (SF), ANKRD12, IFT74, KIAA2026, CCDC18, NEXN, PPIG, and ROCK1 genes in adipose tissue showed potential regulatory effects on adipose-deposition traits. NSRP1 could promote adipogenesis by regulating alternative splicing and expression of CCDC18. Conducting an in-depth investigation into AS, this study has successfully identified key marker genes essential for pig genetic breeding and the enhancement of meat quality, which will play important roles in promoting the diversity of pork quality and meeting market demand.

MicroRNA breed and parent-of-origin effects provide insights into biological pathways differentiating cattle subspecies in fetal liver

Introduction: MicroRNAs (miRNAs) play a crucial role in regulating gene expression during key developmental processes, including fetal development. Brahman (Bos taurus indicus) and Angus (Bos taurus taurus) cattle breeds represent two major cattle subspecies with strikingly different phenotypes. Methods: We analyzed miRNA expression in liver samples of purebred and reciprocal crosses of Angus and Brahman to investigate breed and parent-of-origin effects at the onset of accelerated fetal growth. Results: We identified eight novel miRNAs in fetal liver samples and 14 differentially expressed miRNAs (DEMs) between purebred samples. Correlation of gene expression modules and miRNAs by breed and parent-of-origin effects revealed an enrichment of genes associated with breed-specific differences in traits such as heat tolerance (Brahman) and fat deposition (Angus). We demonstrate that genes predicted to be targets of DEMs were more likely to be differentially expressed than non-targets (p-value < 0.05). We identified several miRNAs (bta-miR-187, bta-miR-216b, bta-miR-2284c, bta-miR-2285c, bta-miR-2285cp, bta-miR-2419-3p, bta-miR-2419-5p, and bta-miR-11984) that showed similar correlation patterns as bta-miR-2355-3p, which has been associated with the glutamatergic synapse pathway, a key facilitator of heat tolerance. Furthermore, we report Angus-breed-specific miRNAs (bta-miR-2313-5p, btamiR-490, bta-miR-2316, and bta-miR-11990) that may be involved in fat deposition. Finally, we showed that the DEMs identified in fetal liver are involved in Rap1, MAPK, and Ras signalling pathways, which are important for fetal development, muscle development and metabolic traits such as fat metabolism. Conclusion: Our work sheds light on the miRNA expression patterns that contribute to gene expression differences driving phenotypic differences in indicine and taurine cattle.

Integrated transcriptome analysis reveals roles of long non-coding RNAs (lncRNAs) in caprine skeletal muscle mass and meat quality

Long non-coding RNAs (lncRNAs) play important roles in the growth and development of skeletal muscle. However, there is limited information on goats. In this study, expression profiles of lncRNAs in Longissimus dorsi muscle from Liaoning cashmere (LC) goats and Ziwuling black (ZB) goats with divergent meat yield and meat quality were compared using RNA-sequencing. Based on our previous microRNA (miRNA) and mRNA profiles obtained from the same tissues, the target genes and binding miRNAs of differentially expressed lncRNAs were obtained. Subsequently, lncRNA-mRNA interaction networks and a ceRNA network of lncRNA-miRNA-mRNA were constructed. A total of 136 differentially expressed lncRNAs were identified between the two breeds. Fifteen cis target genes and 143 trans target genes were found for differentially expressed lncRNAs, and they were enriched in muscle contraction, muscle system process, muscle cell differentiation, and p53 signaling pathway. A total of 69 lncRNA-trans target gene pairs were constructed, with close relationship with muscle development, intramuscular fat deposition, and meat tenderness. A total of 16 lncRNA-miRNA-mRNA ceRNA pairs were identified, of which some reportedly associated with skeletal muscle development and fat deposition were found. The study will provide an improved understanding of the roles of lncRNAs in caprine meat yield and meat quality.

Whole-transcriptome analyses of sheep embryonic testicular cells infected with the bluetongue virus

Introduction

bluetongue virus (BTV) infection triggers dramatic and complex changes in the host's transcriptional profile to favor its own survival and reproduction. However, there is no whole-transcriptome study of susceptible animal cells with BTV infection, which impedes the in-depth and systematical understanding of the comprehensive characterization of BTV-host interactome, as well as BTV infection and pathogenic mechanisms.

Methods

to systematically understand these changes, we performed whole-transcriptome sequencing in BTV serotype 1 (BTV-1)-infected and mock-infected sheep embryonic testicular cells, and subsequently conducted bioinformatics differential analyses.

Results

there were 1504 differentially expressed mRNAs, 78 differentially expressed microRNAs, 872 differentially expressed long non-coding RNAs, and 59 differentially expressed circular RNAs identified in total. Annotation from the Gene Ontology, enrichment from the Kyoto Encyclopedia of Genes and Genomes, and construction of competing endogenous RNA networks revealed differentially expressed RNAs primarily related to virus-sensing and signaling transduction pathways, antiviral and immune responses, inflammation, and development and metabolism related pathways. Furthermore, a protein-protein interaction network analysis found that BTV may contribute to abnormal spermatogenesis by reducing steroid biosynthesis. Finally, real-time quantitative PCR and western blotting results showed that the expression trends of differentially expressed RNAs were consistent with the whole-transcriptome sequencing data.

Discussion

this study provides more insights of comprehensive characterization of BTV-host interactome, and BTV infection and pathogenic mechanisms.

MicroRNA-381 Regulates Proliferation and Differentiation of Caprine Skeletal Muscle Satellite Cells by Targeting PTEN and JAG2

In our previous study, microRNA (miR)-381 was found to be the most down-regulated miRNA in skeletal muscle of Liaoning cashmere goats with higher skeletal muscle mass, but the molecular mechanism involved remains unclear. In this study, primary caprine skeletal muscle satellite cells (SMSCs) were isolated and identified. We investigated the effect of miR-381 on the viability, proliferation and differentiation of caprine SMSCs, and the target relationships of miR-381 with jagged canonical Notch ligand 2 (JAG2) and phosphatase and tensin homolog (PTEN). Cells isolated were positive for SMSC-specific marker protein Pax7. This suggests that purified SMSCs were obtained. The expression level of miR-381 achieved a peak value on day 4 after SMSC differentiation, and miR-381 also significantly increased the expression levels of myogenic differentiation marker genes: myosin heavy chain (MyHC), myogenin (MyoG) and myocyte enhancer factor 2C (MEF2C) in differentiated SMSCs, the area of MyHC-positive myotubes and the myogenic index. These findings suggest that miR-381 promoted myogenic differentiation of caprine SMSCs. The CCK8 assay and EDU staining analysis showed that miR-381 mimic both inhibited the viability of SMSCs and decreased the percentage of EDU-labeled positive SMSCs. In contrast, miR-381 inhibitor had the opposite effect with miR-381 mimic. A dual luciferase reporter assay verified that miR-381 can target JAG2 and PTEN by binding to the 3′-untranslated regions (3′-UTR) of the genes. The transfection of miR-381 mimic into caprine SMSCs resulted in decreases in expression levels of JAG2 and PTEN, while miR-381 inhibitor increased the two target genes in expression. This is the first study to reveal the biological mechanisms by which miR-381 regulates caprine SMSC activities.

Characteristics and Expression of circ_003628 and Its Promoted Effect on Proliferation and Differentiation of Skeletal Muscle Satellite Cells in Goats

Simple Summary

Circular RNAs (circRNAs) are new regulators of the development of skeletal muscle in mammals. Herein, circ_003628 in Longissimus dorsi muscle tissue of goats, previously found by RNA-seq, was selected to construct an expression profile in different caprine tissues, and investigate the effect on proliferation and differentiation of caprine skeletal muscle satellite cells (SMSCs), using RT-qPCR, EdU, CCK-8 and immunofluorescence assays. The results showed that circ_003628 had the highest expression level both in the longissimus dorsi muscle among nine caprine tissues collected, and on day 6 after differentiation during SMSCs differentiation periods. The interfering of circ_003628 inhibited the viability, proliferation, and differentiation of goat SMSCs.

Abstract

In our previous a study, circ_003628 was one of the most highly expressed circular RNAs (circRNAs) in the Longissimus dorsi muscle of goats found by RNA-seq, suggesting that the circRNA may be important for caprine muscle growth and development. However, there have been no reports describing the molecular mechanisms by which circ_003628 regulates the activities of goat skeletal muscle satellite cells (SMSCs). In this study, reverse transcriptase-PCR (RT-PCR) and DNA sequencing were used to validate the authenticity of circ_003628, and its characteristics, expression profile and effect on goat SMSCs were also studied using real-time quantitative-PCR (RT-qPCR), EdU, CCK-8 and immunofluorescence assays. Circ_003628 is partially originated from 13 exons, 12 introns and 3′-untranslated regions (UTR) of caprine Myosin Heavy Chain 1 (MYH1), and 25 exons and 5′ UTR of Myosin Heavy Chain 4 (MYH4), as well as intergenic sequences between the two genes. A total of 77.07% of circ_003628 were located in the nuclei of goat SMSCs, while 22.93% were expressed in the cytoplasm. The circRNAs were only expressed in triceps brachii, quadriceps femoris and longissimus dorsi muscle tissues in nine caprine tissues investigated, with the highest expression level in longissimus dorsi muscle. The expression level of circ_003628 gradually increased during differentiation periods of goat SMSCs and reached the maximum on day 6 after differentiation. The small interfering RNA of circ_003628 (named si-circ_003628) inhibited the viability and proliferation of goat SMSCs, and also decreased the expression of four cell proliferation marker genes: paired box 7 (Pax7), cyclin-dependent kinase 2 (CDK2), CDK4 and CyclinD1 in goat SMSCs. Transfection of si-circ_003628 significantly decreased the area of MyHC-labeled myotubes of goat SMSCs, as well as the expression levels of three differentiation marker genes: myosin heavy chain (MyHC), myogenin (MyoG), and myocyte enhancer factor 2C (MEF2C). These results suggest that circ_003628 promotes the viability, proliferation, and differentiation of goat SMSCs, and they also provide an improved understanding of the roles of circ_003628 in skeletal muscle growth and development in goats.