Nitric oxide contributes to cytokine-induced apoptosis in pancreatic beta cells via potentiation of JNK activity and inhibition of Akt
Nitric oxide contributes to cytokine-induced apoptosis in pancreatic beta cells via potentiation of JNK activity and inhibition of Akt
复制标题
DOI：
10.1007/s00125-005-1912-2
复制
发表时间：
2005-10-01
期刊：
影响因子：
8.2
通讯作者：
Mandrup-Poulsen, T
中科院分区：
文献类型：
--
作者：
Storling, J;Binzer, J;Mandrup-Poulsen, T
目的/假设：促炎细胞因子导致β细胞分泌功能障碍和细胞凋亡--这一过程与1型糖尿病的发病机制有关。细胞因子诱导诱导型一氧化氮合酶(INOS)的表达，导致NO的产生。NO参与了细胞因子诱导的细胞凋亡，但其机制尚不清楚。本研究的目的是研究NO是否通过丝裂原活化蛋白激酶(MAPKs)和Akt来调节信号转导。材料和方法：免疫印迹法和体外激酶法测定INS-1细胞和胰岛MAPK活性。通过酶联免疫吸附试验检测胞浆中存在的组蛋白-DNA复合体来检测细胞的凋亡率。结果：一氧化氮合酶阻断剂N-G-甲基-L-精氨酸证实，IL-1-γ和干扰素-γ诱导的INS-1细胞的凋亡依赖于NO的产生。因此，NO供体(S-亚硝基-N-乙酰-D、L-青霉胺，SNAP)呈剂量依赖性地诱导INS-1细胞凋亡。Snap激活c-jun氨基末端激酶(JNK)和p38MAPK，但抑制细胞外信号调节激酶MAPK的活性。在大鼠胰岛中，一氧化氮合酶抑制降低了IL-1β暴露6小时所诱导的JNK和p38活性。同样，IL-1β诱导的JNK和p38活性在iNOS(-/-)小鼠胰岛中低于野生型胰岛。在人的胰岛中，SNAP增强了IL-1β诱导的JNK激活。SNAP抑制INS-1细胞中活性的、Ser473磷酸化的Akt的组成水平。IGF-I激活Akt，对SNAP诱导的细胞凋亡具有保护作用。IGF-I的抗凋亡作用与JNK活性降低无关。结论/解释：我们认为NO通过增强JNK活性和抑制Akt参与了细胞因子诱导的细胞凋亡。
Aims/hypothesis: Pro-inflammatory cytokines cause beta cell secretory dysfunction and apoptosis - a process implicated in the pathogenesis of type 1 diabetes. Cytokines induce the expression of inducible nitric oxide ( NO) synthase ( iNOS) leading to NO production. NO contributes to cytokine-induced apoptosis, but the underlying mechanisms are unclear. The aim of this study was to investigate whether NO modulates signalling via mitogen-activated protein kinases (MAPKs) and Akt. Materials and methods: MAPK activities in INS-1 cells and isolated islets were determined by immunoblotting and in vitro kinase assay. Apoptosis was determined by ELISA measurement of histone - DNA complexes present in cytoplasm. Results: Apoptosis in INS-1 cells induced by IL-1 gamma plus IFN gamma was dependent on NO production as demonstrated by the use of the NOS blocker N-G-methyl-L-arginine. Accordingly, an NO donor (S-nitroso-N-acetyl-D, L-penicillamine, SNAP) dose-dependently caused apoptosis in INS-1 cells. SNAP activated c-Jun N-terminal kinase (JNK) and p38 MAPK, but suppressed the activity of extracellular signal-regulated kinase MAPK. In rat islets, NOS inhibition decreased JNK and p38 activities induced by a 6-h exposure to IL-1 beta. Likewise, IL-1 beta-induced JNK and p38 activities were lower in iNOS((-/-)) mouse islets than in wild-type islets. In human islets, SNAP potentiated IL-1 beta-induced JNK activation. The constitutive level of active, Ser473-phosphorylated Akt in INS-1 cells was suppressed by SNAP. IGF-I activated Akt and protected against SNAP-induced apoptosis. The anti-apoptotic effect of IGF-I was not associated with reduced JNK activation. Conclusions/interpretation: We suggest that NO contributes to cytokine-induced apoptosis via potentiation of JNK activity and suppression of Akt.