Seed region SNPs alter miRNA expression profile in response to insulin in bovine adipose tissue in vivo

胰岛素是脂肪生成和体内平衡的有效调节剂。低胰岛素血症和脂肪组织（AT）的胰岛素反应性降低同时发生在泌乳早期，导致乳腺非胰岛素依赖性摄取的葡萄糖可用性增加和AT动员增加。虽然有一些证据表明，在哺乳早期脂肪中与胰岛素信号相关的一些基因发生了变化，但转录后机制仍不清楚。微小RNA（microRNA，miRNA）是四种遗传上保守的非蛋白质编码小RNA之一，通过抑制蛋白质翻译或使靶mRNA不稳定来介导转录后基因抑制。在人类中，胰岛素影响microRNA（miRNA）表达谱。此外，有报道表明miRNA的单核苷酸多态性（SNP）对人类药物应答的个体间差异的影响。本研究采用牛体内模型研究泌乳早期胰岛素对皮下AT转录后表达谱的影响。此外，我们将使用分子方法鉴定牛AT中差异表达（上调或下调）miRNA的种子区SNP。为了证实所鉴定的miRNA突变对靶基因mRNA降解的差异效应，我们将在体外研究中使用报告载体。这将代表第一项研究，涉及miRSNP（微RNA SNP）对泌乳早期牛SC中胰岛素反应的影响。

Insulin is a potent regulator of lipogenesis and homeostasis. Hypo-insulinemia and decreased insulin responsiveness of adipose tissue (AT) occur simultaneously in early lactation, resulting in increased glucose availability for insulin-independent uptake by the mammary gland and greater mobilization of AT. Although there is some evidence for changes in some genes associated with insulin signaling in adipose during early lactation, post-transcriptional mechanisms remain unknown. Micro RNA (miRNA) are one of four small, phylogeneticallyconserved, non–protein-coding RNAs that mediate posttranscriptional gene repression by inhibiting protein translation or by destabilizing target mRNA. In humans, insulin affects the micro RNA (miRNA) expression profile. Further, there are reports indicating the effect of miRNAs’ single nucleotide polymorphisms (SNPs) on inter-individual differences in drug response in humans. In this project, a bovine in vivo model will be used to study the effect of insulin in early lactation on post-transcriptional expression profile in subcutaneous (SC) AT. Furthermore, we will identify the seed region SNPs of differentially expressed (up- or downregulated) miRNAs using molecular approaches in bovine AT. To confirm the differential effect of identified miRNA mutations on the target genes’ mRNA degradation, we will use a reporter vector in an in vitro study. This will represent the first study implicating miRSNP (Micro RNA SNP) on insulin response in bovine SC in early lactation.