信号蛋白RasGRP4经介导NK/DC 交叉对话调控糖尿病NK细胞IFN-γ分泌的作用机制研究

2型糖尿病（DM）患者感染的高度易感性和难控制性是困扰临床的一大难题。NK细胞IFNγ分泌受损是DM患者防御能力下降的重要原因，其机制不详。前期研究证实NK细胞IFNγ分泌依赖于信号蛋白Ras鸟苷酸释放蛋白4（RasGRP4），且DM患者树突状细胞（DC）内该信号蛋白异常，据此提出2型DM患者DC内异常的RasGRP4信号介导NK/DC通讯障碍，导致IFNγ分泌受损的假说。为验证该假说，本研究拟采用RasGRP4基因敲除DM小鼠和DM人群，从整体水平揭示RasGRP4信号的变化与NK细胞IFNγ分泌能力的关系；采用CRISPR/Cas9技术敲减和激活RasGRP4，从细胞分子水平证实其调控IFN-γ分泌的作用；通过共培养、抗体阻断等方法阐明其介导NK/DC对话方式及效应分子。从NK/DC细胞通讯障碍的角度揭示DM患者防御能力下降的分子机制，研究结果可望为防治DM患者免疫能力的下降提供新思路

The high risk of infection and difficulty in control infection in patients with type 2 diabetes mellitus (DM) is a major project faced by the clinical; The damage of the IFN – gamma secretion by Natural killer (NK) cell is important reason for the declining defense capabilities of DM patients. Our research team previously identified that the production of IFN – gamma by NK cell depends on the signaling protein Ras guanylic acid release protein 4 (RasGRP4) and we also found out bnormal RasGRP4 signal existed in dendritic cells (DC) in DM patients. On these basis, we proposed the hypothesis :the damage of IFN – gamma by NK cell in diabetic patients has something to do with bnormal RasGRP4 signal which regulates IFN gamma secretion by NK cell via mediating NK - DC cross talk. To test this hypothesis, This study will adopt RasGRP4 knockout DM mice and DM patients to reveal the effect of DM on the signaling protein of ability of IFN -gamma secretion by NK cells from the overall level.We will further use CRISPR/Cas9 technology to reduce and activate RasGRP4 signal respectively to elucidate the mechanism of R asGRP4 regulating IFN- gamma production. And cell co-culture, antibody blocking experiments will further carried out to clarify the way of NK-DC cross-talk and the effective moleculars. This study will reveal the mechanism of defensive ability in diabetic patients from the perspective of NK - DC cell communication barried. the results of the study is expected to provide new ideas for prevention and cure of immunity decline in DM patients.