Table_3_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潜在机制仍有待深入研究。环状RNA是一类新型的非编码RNA，在多种生理和病理过程中具有调控功能。乳生成过程中乳猪的环状RNA的表达谱和功能尚处于未知状态。在本研究中，长期热应激（HS）导致血清中HSP70、LDH和IgG浓度增加，而COR、SOD和PRL水平降低。HS降低了乳猪乳汁中的总固体、脂肪和乳糖含量，并显著抑制了CSNαs1、CSNαs2和CSNκ的生物合成。对乳猪乳腺的转录组测序发现了在HS与对照相比，有42个上调和25个下调的转录本。对这些差异表达转录本的功能注释揭示了四个参与乳生成的热应激诱导基因。此外，在HS的应激反应中发现了29个上调和21个下调的环状RNA候选基因。构建了四个乳生成基因与差异表达环状RNA之间的42个正相关的环状RNA-mRNA表达模式。确定了涉及乳猪乳生成HS反应中基因的五个环状RNA-miRNA-mRNA转录后网络。在本研究中，我们建立了一个用于乳猪哺乳期环状RNA生物学的宝贵资源。对环状RNA-miRNA-mRNA网络的进一步分析揭示了转录后调控的一个新层次，这可用于提高乳猪的产奶量。