Positive modulation by Ras of interleukin-1β-mediated nitric oxide generation in insulin-secreting clonal β (HIT-T15) cells
Positive modulation by Ras of interleukin-1β-mediated nitric oxide generation in insulin-secreting clonal β (HIT-T15) cells
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DOI：
10.1016/s0006-2952(01)00818-8
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发表时间：
2001-12-01
影响因子：
5.8
通讯作者：
Kowluru, A
中科院分区：
文献类型：
--
作者：
Tannous, M;Amin, R;Kowluru, A
在本研究中，我们已经证明，胰岛素分泌克隆性β细胞(HIT-T15)暴露于白介素10(IL-1β)会导致一氧化氮(NO)释放呈时间和浓度依赖性增加。IL-1β对NO释放的这些影响是通过诱导细胞诱导型一氧化氮合酶(INOS)介导的。用索氏梭状芽孢杆菌致死毒素-82预先孵育HIT细胞，该毒素可不可逆地糖基化并灭活小G蛋白，如Ras、Rap、Ral和Rac，而不是CDC42，完全消除IL-1β诱导的NO释放。索氏杆菌致死毒素-9048可单糖化并抑制Ras、CDC42、Rac和Rap，但不能抑制Rap，预先暴露于该毒素也可减弱IL-1β介导的NO释放。这些数据表明，RAS和/或RAC的激活可能是IL-1β介导的NO释放所必需的。艰难梭菌毒素B与艰难梭菌毒素B预先孵育，对IL介导的NO释放没有明显影响，排除了RAC可能参与这一信号转导步骤的可能性。此外，两种结构不同的RAS功能抑制剂，即甘露霉素A和达南棘皮酚，以浓度依赖的方式抑制IL-1β介导的NO从这些细胞释放。总之，我们的数据第一次提供了证据，证明RAS激活是IL-1β介导的NO释放以及随后的胰腺β细胞功能障碍的必经步骤。我们的数据也为进一步研究细胞因子诱导的β细胞死亡导致胰岛素依赖型糖尿病的发病机制提供了基础。(C)2001 Elsevier Science Inc.保留所有权利。
In the present study, we have shown that exposure of insulin-secreting clonal beta (HIT-T15) cells to interleukin-lo (IL-1 beta) results in a time- and concentration-dependent increase in nitric oxide (NO) release. These effects by IL-1 beta on NO release were mediated by induction of inducible nitric oxide synthase (iNOS) from the cells. Preincubation of HIT cells with Clostridium sordellii lethal toxin-82, which irreversibly glucosylates and inactivates small G-proteins, such as Ras, Rap, Ral, and Rac, but not Cdc42, completely abolished IL-1 beta -induced NO release. Pre-exposure of HIT cells to C. sordellii lethal toxin-9048, which monoglucosylates and inhibits Ras, Cdc42, Rac, and Rap, but not Ral, also attenuated IL-1 beta -mediated NO release. These data indicate that activation of Ras and/or Rac may be necessary for IL-1 beta -mediated NO release. Preincubation of HIT cells with C. difficile toxin-B, which monoglucosylates Rac, Cdc42, and Rho, had no demonstrable effects on IL-mediated NO release, ruling out the possibility that Rac may be involved in this signaling step. Further, two structurally dissimilar inhibitors of Ras function, namely manumycin A and damnacanthal, inhibited, in a concentration-dependent manner, the IL-1 beta -mediated NO release from these cells. Together, our data provide evidence, for the first time, that Ras activation is an obligatory step in IL-1 beta -mediated NO release and, presumably, the subsequent dysfunction of the pancreatic beta cell. Our data also provide a basis for future investigations to understand the mechanism of cytokine-induced beta cell death leading to the onset of insulin-dependent diabetes mellitus. (C) 2001 Elsevier Science Inc. All rights reserved.