高雄激素诱导的CFTR表达上调在PCOS高胰岛素血症发生中的作用与机制研究

Polycystic ovary syndrome (PCOS) is a common endocrine disorder in women of reproductive age, featured with hyperandrogenism and hyperinsulinemia. However, the exact mechanism underlying the development of hyperinsulinemia seen in PCOS remains elusive. Moreover, whether excessive androgen contributes to hyperinsulinemia in the context of PCOS has not been explored. Our previous report has found that excessive androgen elevates CFTR expression, resulting in suppression on glucagon expression in islet alpha cells. In the preliminary study, we have observed that the expression of both CFTR and insulin were increased in islet beta cells in PCOS rats. Androgen enhanced CFTR expression and insulin secretion in islet beta cells. Therefore, we hypothesized that excessive androgen may enhance CFTR expression, then the abnormally high expression of CFTR may promote insulin expression and secretion, which may contribute to hyperinsulinemia. In the proposed study, we aim to: 1. explore the relationship of CFTR, androgen and insulin levels by PCOS patient samples and PCOS rat model; 2. demonstrate that androgen promotes insulin expression and secretion via inducing CFTR upregulation in islets of PCOS rats, mouse islets and a beta cell line with overexpression or knockdown of androgen receptor (AR) or with knockdown or mutation of CFTR; 3. elucidate the mechanisms involved in androgen regulating CFTR expression, as well as in CFTR regulating insulin expression and secretion in mouse islets and a beta cell line with AR or CFTR manipulation, together with calcium channel inhibition. These results will reveal an unrecognized regulatory mechanism for insulin expression and secretion in PCOS, which may contribute to hyperinsulinemia. Our findings will provide new insights into the understanding of the pathogenesis of hyperinsulinemia and may provide grounds for the development of new therapeutic approaches for hyperinsulinemia in PCOS.

多囊卵巢综合征（PCOS）普遍存在高雄激素血症和高胰岛素血症。然而高胰岛素血症的发生机制仍不清楚，是否由高雄激素诱发也未明确。我们已报道：高雄激素通过上调CFTR抑制胰高血糖素表达。预实验发现：PCOS大鼠胰岛beta细胞中CFTR和胰岛素表达升高；雄激素促进beta细胞CFTR表达及胰岛素分泌。据此推测：雄激素可能诱导CFTR表达上调，进而引起胰岛素表达及分泌增多，参与PCOS高胰岛素血症发生。本项目拟采用PCOS患者及大鼠模型，明确雄激素、CFTR及胰岛素水平之间的相关性；采用PCOS大鼠胰岛、雄激素受体过表达/敲低、CFTR敲低/突变小鼠胰岛及beta细胞系，证明雄激素通过上调CFTR促进胰岛素表达和分泌；采用以上基因操纵细胞及钙通道抑制，探讨雄激素调控CFTR及CFTR调控胰岛素的机制。旨在丰富胰岛素表达及分泌的调控机制,为揭示PCOS高胰岛素血症的发生机制及防治提供新的理论依据。

多囊卵巢综合征（PCOS）普遍存在高雄激素血症和高胰岛素血症。然而高胰岛素血症的发生机制仍不清楚，是否由高雄激素诱发也未明确。我们提出假设：雄激素可能诱导CFTR表达上调，进而引起胰岛素表达及分泌增多，参与PCOS高胰岛素血症发生。本项目采用临床PCOS外周血样本，并构建PCOS大鼠模型，证明PCOS患者外周血中胰岛素、睾酮和CFTR水平高于对照组女性，PCOS患者与对照组女性外周血中睾酮水平与CFTR 蛋白水平呈正相关性; 且PCOS大鼠胰岛β细胞中CFTR表达水平和insulin的表达水平均高于对照组大鼠。采用分离小鼠原代胰岛、大鼠胰岛β细胞系RINm5F和小鼠胰岛β细胞系B-TC-6等模型，通过雄激素拮抗剂、CFTR抑制剂等干扰手段及一系列细胞和分子生物学实验，证明：雄激素促进CFTR表达和insulin的表达和分泌，CFTR调控胰岛素的转录表达和分泌，并明确雄激素/雄激素受体（AR）促进胰岛素分泌是由CFTR介导的；进而阐明雄激素/AR通过与CFTR启动子区结合促进CFTR转录表达；阐明雄激素诱导的CFTR表达上调促进p-CREB表达，从而促进insulin转录表达；阐明CFTR改变细胞内膜电位引起细胞内钙反应，从而促进胰岛素分泌。以上研究结果丰富了胰岛素表达及分泌的调控机制,为揭示PCOS高胰岛素血症的发生机制及防治提供新的理论依据。