Table_2_Emerging Roles of Heat-Induced circRNAs Related to Lactogenesis in Lactating Sows.xlsx

Heat stress negatively influences milk production and disrupts normal physiological activity of lactating sows, but the precious mechanisms by which hyperthermia adversely affects milk synthesis in sows still remain for further study. Circular RNAs are a novel class of non-coding RNAs with regulatory functions in various physiological and pathological processes. The expression profiles and functions of circRNAs of sows in lactogenesis remain largely unknown. In the present study, long-term heat stress (HS) resulted in a greater concentration of serum HSP70, LDH, and IgG, as well as decreased levels of COR, SOD, and PRL. HS reduced the total solids, fat, and lactose of sow milk, and HS significantly depressed CSNαs1, CSNαs2, and CSNκ biosynthesis. Transcriptome sequencing of lactating porcine mammary glands identified 42 upregulated and 25 downregulated transcripts in HS vs. control. Functional annotation of these differentially-expressed transcripts revealed four heat-induced genes involved in lactation. Moreover, 29 upregulated and 21 downregulated circRNA candidates were found in response to HS. Forty-two positively correlated circRNA-mRNA expression patterns were constructed between the four lactogenic genes and differentially expressed circRNAs. Five circRNA-miRNA-mRNA post-transcriptional networks were identified involving genes in the HS response of lactating sows. In this study we establish a valuable resource for circRNA biology in sow lactation. Analysis of a circRNA-miRNA-mRNA network further uncovered a novel layer of post-transcriptional regulation that could be used to improve sow milk production.

热应激对乳猪的产奶量产生负面影响，并扰乱其正常的生理活动，然而，高温对乳猪乳汁合成产生不利影响的具体机制仍有待深入研究。环状RNA（Circular RNAs）是一类新兴的非编码RNA，在多种生理和病理过程中发挥调控作用。关于乳猪在泌乳过程中的环状RNA的表达谱和功能仍知之甚少。在本研究中，长期热应激（HS）导致血清中HSP70、LDH和IgG浓度升高，同时COR、SOD和PRL水平降低。HS减少了母猪乳汁中的总固形物、脂肪和乳糖含量，并且显著降低了CSNαs1、CSNαs2和CSNκ的生物合成。对泌乳母猪乳腺的转录组测序发现，在HS组与对照组相比，有42个基因表达上调，25个基因表达下调。这些差异表达基因的功能注释揭示了四个与泌乳相关的热应激诱导基因。此外，在HS的刺激下，发现了29个上调和21个下调的环状RNA候选基因。在四个泌乳基因和差异表达的环状RNA之间构建了42个正相关的环状RNA-mRNA表达模式。确定了涉及乳猪热应激反应的基因的五个环状RNA-miRNA-mRNA转录后调控网络。本研究为母猪泌乳过程中的环状RNA生物学研究提供了一个宝贵的资源。对环状RNA-miRNA-mRNA网络的进一步分析揭示了转录后调控的新层面，这可能有助于提高母猪的产奶量。