Mechanisms of immunoregulation by serine proteinase inhibitor and its application of therapy for rheumatic disease

1)NK细胞死亡与丝氨酸蛋白酶抑制因子9(PI-9)在这里我们发现NK细胞的激活伴随着颗粒酶B从细胞内颗粒渗入细胞质。颗粒酶B渗漏的证据包括免疫沉淀检测到的颗粒酶B/丝氨酸蛋白酶抑制物9(PI-9)复合体的形成以及免疫细胞化学检测到的颗粒酶B和PI-9的共存。颗粒酶B的特异性底物BID在CD2诱导NK细胞活化后2分钟内被切割，提示颗粒酶B通过将BID导向线粒体膜而触发细胞凋亡。颗粒酶B/PI-9蛋白比率被发现反映了CD2诱导的NK细胞死亡的百分比，这表明泄漏的颗粒酶B超过其抑制剂是细胞死亡的主要决定因素。我们认为颗粒酶B渗漏诱导的细胞死亡是激活诱导的NK细胞死亡的重要决定因素，这一过程可能与NK细胞遭遇恶性细胞或病毒感染细胞的命运有关。2)类风湿性关节炎(RA)和PI-9。用ELISA法检测同一RA患者血清和滑膜中IL-1、β和IL-18的滴度。IL-1β和IL-18均来源于RA滑膜。免疫组织化学显示PI-9表达于巨噬细胞样滑膜细胞(A型)。免疫印迹法检测到Caspase1和PI-9在RA滑膜中均有表达。半胱氨酸天冬氨酸蛋白酶1/PI-9蛋白比值反映滑膜产生IL-1β，而不是IL-18，提示PI-9可能通过抑制Caspase1来调节IL-1β的产生，PI-9在调节滑膜NK细胞死亡和IL-1β产生中起关键作用。

1) NK cell death and serpin proteinase inhibitor 9 (PI-9)Here we show that NK cell activation is accompanied by the leakage of granzyme B from intracellular granules into the cytoplasm. Evidence for granzyme B leakage includes the formation of granzyme B/ serine proteinase inhibitor 9 (PI-9) complexes that are detected by immunoprecipitation as well as colocalization of granzyme B and PI-9 detected by immunocytochemistry. The proapoptotic molecule Bid, a specific substrate for granzyme B, was cleaved within 2 min following CD2-induced NK cell activation, suggesting that granzyme B triggers apoptosis by directing Bid to mitochondrial membranes. The granzyme B/PI-9 protein ratio was found to mirror the percentage of CD2-induced NK cell death, suggesting that an excess of leaked granzyme B over its inhibitor is a major determinant of cell death. We suggest that granzyme B leakage-induced cell death (GLCD) is an important determinant of activation-induced NK cell death and that this process may be important for the fate of NK cells which encounter malignant cells or virus-infected cells.2) Rheumatoid arthritis (RA) and PI-9We examined the titer of IL-1β and IL-18 in sera and synovium derived from same RA patients by ELISA. Both IL-1β and IL-18 were produced from RA synovium. In immunohistochemistry, PI-9 was stained in macrophage-like synovial cells (type A). Both caspase 1 and PI-9 were detected in RA synovium using western blotting study. The caspase 1/PI-9 protein ratio was found to mirror the production of IL-1β, but not IL-18 from synovium, suggesting that PI-9 may regulate IL-1β production via caspase 1 inhibition.PI-9 plays the critical roles for the regulation of NK cell death and IL-1β production from RA synovium.