Castration can reduce odor and fights in boars, but the carcass yield is reduced, and the intramuscular fat content is increased. Understanding its molecular mechanism is of great significance for production. Recent studies have shown that circular RNAs (circRNAs) play an important role(s) in the regulation of muscle development. To explore the effects of circRNAs on the development of longissimus dorsi (LD) muscle after castration, six Huainan male pigs were selected and three of which were randomly castrated. Six pigs were slaughtered when their body weight reached around 130 kg, and the LD muscle samples were collected. The differentially expressed circRNAs (DECs) were screened by high-throughput sequencing and functionally analyzed using the KEGG databases. DECs-miRNAs network was constructed, and the expression profiles of candidate circRNAs and their interactions with miRNAs were verified in porcine skeletal muscle satellite cells. The results showed that a total of 5866 circRNAs were obtained, and 370 DECs were identified in LD muscle between the castrated and intact groups (| log2Foldchange | > 1, padj <0.8). KEGG enrichment indicated that the parental genes for the DECs were mainly enriched in the pathways associated with muscle development, muscle fiber type transformation, and energy metabolism. There were 8 miRNAs and 69 circRNAs enriched in the DECs-miRNA network. circRNA_2241 and circRNA_4237 were selected for verification, which showed that these two circRNAs really existed and their expression profiles were consistent with the sequencing results. Further, preliminary analysis showed that circRNA_2241 interacted with miR-1, and testosterone promoted circRNA_2241 but inhibited miR-1 expression. These results confirmed that circRNAs might participate in the regulation of LD muscle development after castration by interacting with miRNAs, thereby providing new materials and references for analyses on the molecular mechanisms of castration on the regulation of muscle development.
公猪去势可减少异味和打斗,但去势后产肉量和肌内脂肪沉积发生变化,其分子机制的解析对生产具有重要意义。近年来研究表明,环状RNA (circRNA)在肌肉发育中具有重要调控作用。为探究去势后circRNAs对背最长肌发育的调控,本研究选择6头淮南公猪,随机选择3头去势,当体重达130 kg左右屠宰,采集背最长肌样品,利用高通量测序筛选差异表达circRNAs (differentially expressed circRNAs, DECs)并进行KEGG功能富集分析。结合前期筛选的公猪去势相关miRNAs,构建DECs-miRNAs调控网络,最后使用猪骨骼肌卫星细胞验证候选circRNA表达谱及其与miRNA互作关系。结果表明,去势和非去势组背最长肌样品共获得5866个circRNAs,两组之间共有370个DECs (| log2Foldchange | > 1, padj<0.8),KEGG富集分析表明,DECs来源母基因主要富集于肌肉发育、肌纤维类型转化、能量代谢等相关通路。构建的DECs-miRNA调控网络共包括69个circRNAs和8个miRNAs。选择circRNA_2241和circRNA_4237进行验证,结果发现这两个circRNAs真实存在且表达趋势与测序结果一致。进一步在猪骨骼肌卫星细胞初步验证circRNA_2241与miR-1互作关系,结果表明睾酮显著促进circRNA_2241表达,同时抑制miR-1表达。本研究结果提示circRNAs可能通过与miRNAs互作调控猪去势后背最长肌发育,从而为解析去势对肌肉发育调控的分子机制提供参考。.
Keywords: castration; circRNAs; longissimus muscle; male pigs.