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

1)NK细胞死亡和丝氨酸蛋白酶抑制剂9（PI-9）在这里，我们表明，NK细胞活化伴随着颗粒酶B从细胞内颗粒泄漏到细胞质中。颗粒酶B渗漏的证据包括颗粒酶B/丝氨酸蛋白酶抑制剂9（PI-9）复合物的形成（通过免疫沉淀法检测）以及颗粒酶B和PI-9的共定位（通过免疫细胞化学法检测）。促凋亡分子Bid是颗粒酶B的特异性底物，在CD 2诱导的NK细胞活化后2分钟内被裂解，表明颗粒酶B通过将Bid引导至线粒体膜来触发凋亡。发现颗粒酶B/PI-9蛋白比率反映了CD 2诱导的NK细胞死亡的百分比，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（GLCD）是活化诱导的NK细胞死亡的一个重要决定因素，这一过程可能对NK细胞在遇到恶性细胞或病毒感染细胞时的命运具有重要意义。2）类风湿性关节炎（RA）和PI-9 IL-1β和IL-18均来源于RA滑膜。免疫组化结果显示，PI-9在巨噬细胞样滑膜细胞（A型）中染色。免疫印迹法检测RA滑膜中caspase 1和PI-9的表达。Caspase 1/PI 9蛋白比值与RA滑膜IL 1β的产生有关，而与IL 18的产生无关，提示PI 9可能通过抑制Caspase 1来调节IL 1β的产生，PI 9在RA滑膜NK细胞死亡和IL 1β的产生中起重要作用。

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.