BTLA通过ASNA-1调节β细胞功能的机制研究

Diabetes is a metabolic disorders disease characterized by chronic hyperglycemia, which effects human health seriously. Thus, controlling the occurrence and development and reducing complications are urgent. Endoplasmic reticulum stress (ERS) is associated with β-cell apoptosis and insulin secretion reduction, both of which are related to diabetes. ASNA-1 regulates ERS and β-cell function though the tail-anchored proteins. However, the mechanism of regulating ASNA-1 is unclear. Our preliminary research revealed that BTLA expressed in pancreatic β cells and binds to ASNA-1 directly. BTLA knockout mice showed a high fasting blood glucose, low fasting blood insulin and lack of glucose-stimulated insulin secretion, suggesting that BTLA may regulate insulin secretion through ASNA-1. In this study, we are going to construct BTLA-specific gene knockout in β cell mice to explore how BTLA regulates the function of β cells, and analyze the apoptosis of NIT-1 pancreatic cancer cells in vitro by WB and RNAi. In the last, we will block the BTLA signal with antibodies to explore the effects of BTLA on diabetes and insulin resistance. This research will clear how BTLA regulate the function mechanism of pancreatic β cell, which have a significant on the clinical treatment of diabetes and other diseases.

I型糖尿病（TIMD）是以胰腺β细胞分泌胰岛素严重不足导致的代谢紊乱性疾病。内质网应激(ERS)反应可引起β细胞凋亡及胰岛素分泌减少，促进TIMD的发生。ASNA-1可通过调控尾锚定蛋白的定向转运，抑制ERS并促进β细胞存活，但ASNA-1的调节机制尚未知。前期研究我们发现免疫辅助信号分子BTLA表达于β细胞并促进ASNA-1表达。BTLA-/-小鼠有高空腹血糖、低空腹血胰岛素等特征，提示BTLA可能通过促进ASNA-1改善β细胞功能，但机制未清楚。本研究拟使用WB等技术体外分析BTLA通过PI3K/Akt-STATs通路促进ASNA-1表达的分子机制；构建BTLAβ-/-小鼠，探讨BTLA对β细胞凋亡及功能的影响；最后使用抗体阻断BTLA信号，分析其对TIMD发展的干预效果。本研究将明确BTLA调控β细胞功能的分子机制，为TIMD的临床提供新策略。

糖尿病是以慢性高血糖为特征的代谢紊乱性疾病，其危害极大。因此，控制糖尿病的发生发展并减少并发症成为迫切需要解决的问题。内质网应激 (Endoplasmic reticulum Stress，ERS)反应可引起胰腺β细胞凋亡及胰岛素分泌减少，在糖尿病的发生起关键作用。ASNA-1可调控尾锚定蛋白的定向转运，从而调节ERS及β细胞功能，但调节ASNA-1的表达与调控的分子机制尚为未知。本课题的研究我们系统地探讨了BTLA-ASNA-1信号通路对糖尿病及肥胖症的调控及其机制。我们研究发现：1）BTLA表达于胰腺β细胞并与ASNA-1直接结合，而BTLA-/-小鼠有高空腹血糖、低空腹血胰岛素、葡萄糖刺激胰岛素分泌不足等特征；2）构建β细胞BTLA特异性基因敲除小鼠（BTLAβ-/-），发现BTLA基因敲除可促进β细胞分泌肝糖原；3）使用Co-IP技术结合酵母双杂交技术，发现BTLA能与ASNA-1结合；使用RNAi技术特异性干扰ASNA-1基因在NIT-1胰腺癌β细胞中的表达，发现ASNA-1缺乏可导致细胞凋亡及胰岛素分泌功能升高；5）发现T细胞特异敲除BTLA后也可影响高脂诱导的肥胖，与脂肪代谢酶的激活相关；6）T细胞特异敲除BTLA小鼠可影响主动产热。本研究明确BTLA影响肥胖及胰岛素抵抗的机制，对糖尿病等疾病的临床治疗有重要意义。