CircNDST1 Regulates Bovine Myoblasts Proliferation and Differentiation via the miR-411a/Smad4 Axis

Estrogen-induced circFAM171A1 regulates sheep myoblast proliferation through the oar-miR-485-5p/MAPK15/MAPK pathway

Estrogen is an important hormone that affects muscle development in female animals. Previous studies have shown that estrogen can protect muscle cells from apoptosis by inhibiting the MAPK signaling pathway. However, the molecular mechanisms by which estrogen-induced MAPK signaling regulates myoblast growth and development remain unclear. In this study, RNA-seq was performed on ovariectomized small-tailed Han (OR-STH) sheep and sham surgery small-tailed Han (STH) sheep to analyze the effects of estrogen on muscle growth and development in female animals. There were 8721 differentially expressed circRNAs (DECs), 143 differentially expressed miRNAs (DEMs) and 2238 differentially expressed mRNAs (DEGs) in the longissimus dorsi between the OR-STH and STH groups. Bioinformatics analysis revealed that the differentially expressed gene MAPK15 was significantly enriched in the MAPK signaling pathway, which is important for muscle development. Therefore, we constructed the ceRNA network circFAM171A1/oar-miR-485-5p/MAPK15 and explored its effect on muscle growth and development. The results of the molecular mechanism experiments indicated that circFAM171A1 can sponge oar-miR-485-5p to regulate MAPK15. The addition of the exogenous hormone estradiol (E2) to sheep myoblasts could induce circFAM171A1, regulate the expression of oar-miR-485-5p and MAPK15, and promote the proliferation of sheep myoblasts. The results showed that MAPK15 and circFAM171A1 significantly promoted the proliferation of myoblasts and inhibited the apoptosis of myoblasts in sheep, whereas oar-miR-485-5p inhibited the expression of MAPK15 and circFAM171A1, inhibited myoblast proliferation and promoted apoptosis. Furthermore, circFAM171A1 attenuated the inhibitory effect of oar-miR-485-5p on myoblasts. In summary, estrogen induced the expression of circFAM171A1 in sheep myoblasts, and circFAM171A1 can act as a sponge for oar-miR-485-5p to promote the expression of the target gene MAPK15 and ultimately regulate the proliferation of sheep myoblasts. This study provides new insights into the molecular mechanism of estrogen regulation of muscle growth and development in female animals.

oar-miR-411a-5p Promotes Proliferation and Differentiation in Hu Sheep Myoblasts Under Heat Stress by Targeting SMAD2

MicroRNAs (miRNAs) are endogenous noncoding RNAs that produce a remarked effect on regulating posttranscriptional gene expression. Our previous study identified a decrease in the expression of oar-miR-411a-5p from umbilical plasma in intrauterine growth restriction (IUGR) Hu lambs subjected to maternal heat stress. In this study, we demonstrated that oar-miR-411a-5p could modulate skeletal muscle development. Overexpression of oar-miR-411a-5p significantly enhanced proliferation and differentiation in heat-stressed Hu sheep myoblasts while suppressing apoptosis. Conversely, inhibition of oar-miR-411a-5p resulted in opposing effects. Subsequently, RNAhybrid analysis revealed targeted sites between oar-miR-411a-5p and the 3' untranslated region (UTR) of SMAD2. This suggested that SMAD2 is a direct target gene of oar-miR-411a-5p, as its expression was negatively modulated by oar-miR-411a-5p, a finding corroborated by dual-luciferase assay and RT-qPCR. Furthermore, co-transfection of oar-miR-411a-5p and SMAD2 into Hu sheep myoblasts indicated that oar-miR-411a-5p modulated heat-stressed myoblast growth by targeting SMAD2. In conclusion, these findings elucidate the function of oar-miR-411a-5p in promoting the development of heat-stressed Hu sheep myoblasts, thereby enhancing our understanding of how miRNAs influence skeletal muscle growth in heat-stressed Hu sheep.

CircRNA profiling of skeletal muscle satellite cells in goats reveals circTGFβ2 promotes myoblast differentiation

BACKGROUND

Circular RNAs (circRNAs) function as essential regulatory elements with pivotal roles in various biological processes. However, their expression profiles and functional regulation during the differentiation of goat myoblasts have not been thoroughly explored. This study conducts an analysis of circRNA expression profiles during the proliferation phase (cultured in growth medium, GM) and differentiation phase (cultured in differentiation medium, DM1/DM5) of skeletal muscle satellite cells (MuSCs) in goats.

RESULTS

A total of 2,094 circRNAs were identified, among which 84 were differentially expressed as determined by pairwise comparisons across three distinct groups. Validation of the expression levels of six randomly selected circRNAs was performed using reverse transcription PCR (RT-PCR) and quantitative RT-PCR (qRT-PCR), with confirmation of their back-splicing junction sites. Enrichment analysis of the host genes associated with differentially expressed circRNAs (DEcircRNAs) indicated significant involvement in biological processes such as muscle contraction, muscle hypertrophy, and muscle tissue development. Additionally, these host genes were implicated in key signaling pathways, including Hippo, TGF-beta, and MAPK pathways. Subsequently, employing Cytoscape, we developed a circRNA-miRNA interaction network to elucidate the complex regulatory mechanisms underlying goat muscle development, encompassing 21 circRNAs and 47 miRNAs. Functional assays demonstrated that circTGFβ2 enhances myogenic differentiation in goats, potentially through a miRNA sponge mechanism.

CONCLUSION

In conclusion, we identified the genome-wide expression profiles of circRNAs in goat MuSCs during both proliferation and differentiation phases, and established that circTGFβ2 plays a role in the regulation of myogenesis. This study offers a significant resource for the advanced exploration of the biological functions and mechanisms of circRNAs in the myogenesis of goats.

Role of circPAPD7 in regulating proliferation and differentiation of goat skeletal muscle satellite cells

The circular RNA (circRNA) plays a crucial role in various biological processes, particularly posttranscriptional regulation. However, the role of circRNA in the development of goat skeletal muscle has not been thoroughly explored. Here, we identified circPAPD7, which is a novel circular RNA that is preferentially expressed in the skeletal muscle. Functional assays demonstrated that circPAPD7 promoted proliferation and inhibited differentiation in goat skeletal muscle satellite cells (MuSCs). Mechanistically, it was discovered that circPAPD7 interacts with miR-26a-5p. Moreover, the rescue experiments indicated that the overexpression of circPAPD7 may reverse the inhibitory impact of miR-26a-5p on myoblast proliferation and the accelerated effects on differentiation. Furthermore, we provided evidence that circPAPD7 functions as a sponge for miR-26a-5p, thereby facilitating the upregulation of EZH2 expression in goat MuSCs. Together, the results revealed that circPAPD7 promote proliferation and inhibit differentiation of goat MuSCs via the miR-26a-5p/EZH2 pathway.

Circ_002033 Regulates Proliferation, Apoptosis, and Oxidative Damage of Bovine Mammary Epithelial Cells via the miR-199a-5p-MAP3K11 Axis in Heat Stress

Heat stress is becoming the major factor regarding dairy cow health and milk quality because of global warming. Circular RNAs (circRNAs) represent a special type of noncoding RNAs, which are related to regulating many biological processes. Nonetheless, little is known concerning their effects on heat-stressed bovine mammary epithelial cells (BMECs). Here, this study found a novel circRNA, circ_002033, using RNA sequencing (RNA-seq) and explored the role and underlying regulatory mechanism in proliferation, apoptosis, and oxidative damage in a heat-stressed bovine mammary epithelial cell line (MAC-T). According to the previous RNA-seq analysis, the abundance of circ_002033 in mammary gland tissue of heat-stressed cows increased relative to nonheat-stressed counterparts. This study found that the knockdown of circ_002033 promoted proliferation and alleviated apoptosis and oxidative damage in heat-stressed MAC-T. Mechanistically, circ_002033 localizes to miR-199a-5p in the cytoplasm of MAC-T to regulate mitogen-activated protein kinase kinase 11 (MAP3K11) expression. Meanwhile, miR-199a-5p and MAP3K11 are also involved in regulating the proliferation and apoptosis of heat-stressed MAC-T. Importantly, circ_002033 knockdown promoted the expression of miR-199a-5p while decreasing that of MAP3K11, thereby enhancing proliferation while alleviating apoptosis and oxidative damage in heat-stressed MAC-T. In summary, we found that circ_002033 regulates the proliferation, apoptosis, and oxidative damage of heat-stressed BMECs through the miR-199a-5p/MAP3K11 axis, providing the theoretical molecular foundation for mitigating heat stress of dairy cows.

Whole-transcriptome analysis of longissimus dorsi muscle in cattle-yaks reveals the regulatory functions of ADAMTS6 gene in myoblasts

Cattle-yak, which is the hybrid F1 generation of cattle and yak, demonstrates better production performance compared to yak. However, there is limited research on the molecular mechanisms responsible for the muscle development of cattle-yak. To address this knowledge gap, a comprehensive transcriptomic survey of the longissimus dorsi muscle in cattle-yak was conducted. Three transcript types, namely lncRNAs, miRNAs, and circRNAs, along with protein-coding genes were characterized at two developmental stages (6 m, 18 m) of cattle-yak. The results revealed significant enrichment of these transcripts into pathways related to myoblast differentiation and muscle development signaling. Additionally, the study identified the TCONS00024465/circHIPK3-bta-miR-499-ADAMTS6 regulatory network, which may play a crucial role in the muscle development of cattle-yak by combining the transcriptome data of yak and constructing the ceRNA co-expression network. HEK 293 T cells were used to validate that TCONS00024465 and circHIPK3 are located upstream of bta-miR-499, and can competitively bind to bta-miR-499 as ceRNA. The study also verified that ADAMTS6 regulates skeletal muscle development by inhibiting myoblast proliferation, promoting myoblast differentiation, and positively regulating the apoptosis of myoblasts. Taken together, this study provides new insights into the advantages of cattle-yak production performance and offers a molecular basis for further research on muscle development.

CircRRAS2 promotes myogenic differentiation of bovine MuSCs and is a novel regulatory molecule of muscle development

The proliferation and myogenic differentiation of muscle stem cells (MuSCs) are important factors affecting muscle development and beef quality. There is increasing evidence that circRNAs can regulate myogenesis. We found a novel circRNA, named circRRAS2 that is significantly upregulated in the differentiation phase of bovine MuSCs. Here, we aimed to determine its roles in the proliferation and myogenic differentiation of these cells. The results showed that circRRAS2 was expressed in several bovine tissues. CircRRAS2 inhibited MuSCs proliferation and promoted myoblast differentiation. In addition, chromatin isolation by using RNA purification and mass spectrometry in differentiated muscle cells identified 52 RNA-binding proteins that could potentially bind to circRRAS2, in order to regulate their differentiation. The results suggest that circRRAS2 could be a specific regulator of myogenesis in bovine muscle.HighlightsCircRRAS2 expression is higher in DM cells than in GM cells.CircRRAS2 could significantly inhibit the proliferation and apoptosis of bovine MuSCs.CircRRAS2 promotes the differentiation of bovine MuSCs into myotubes.CircRRAS2 may exert regulatory effects through multiple RNA binding proteins.

The Function and Regulation Mechanism of Non-Coding RNAs in Muscle Development

Animal skeletal muscle growth is regulated by a complex molecular network including some non-coding RNAs (ncRNAs). In this paper, we review the non-coding RNAs related to the growth and development of common animal skeletal muscles, aiming to provide a reference for the in-depth study of the role of ncRNAs in the development of animal skeletal muscles, and to provide new ideas for the improvement of animal production performance.