Protein kinase Cδ activation by interleukin-1β stabilizes inducible nitric-oxide synthase mRNA in pancreatic β-cells
Protein kinase Cδ activation by interleukin-1β stabilizes inducible nitric-oxide synthase mRNA in pancreatic β-cells
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DOI：
10.1074/jbc.m010036200
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发表时间：
2001-02-16
影响因子：
4.8
通讯作者：
Biden, TJ
中科院分区：
文献类型：
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作者：
Carpenter, L;Cordery, D;Biden, TJ
胰岛暴露于细胞因子如白细胞介素（IL）-1 β诱导多种促炎基因，包括II型一氧化氮合酶（MOS），其产生一氧化氮（NO）。NO被认为是胰岛β细胞功能障碍和凋亡性β细胞死亡的主要原因，其导致I型糖尿病。由于蛋白激酶C（PKC）介导其他细胞类型中细胞因子的某些作用，我们的目的是评估PKC在IL-1 β诱导的胰腺β细胞中iNOS表达中的作用。通过膜转位评估，PKC δ而不是PKC α在大鼠INS-1 β细胞系中被IL-1 β特异性激活。此外，MOS的表达和NO的产生显着衰减的PKC δ特异性抑制剂rottlerin和过度表达的PKC δ激酶死亡突变蛋白。相反，PKC δ野生型蛋白的过表达显著增强了这种反应。通过逆转录-聚合酶链反应在mRNA水平证实了这些结果。然而，在转录调控水平的作用似乎不太可能，因为PKC δ不是激活NF-κ B，激活蛋白1，激活转录因子2信号通路响应IL-1 β所必需的。然而，有一个显着增加的MOS mRNA的稳定性介导的PKC δ野生型，而PKC δ激酶死亡的作用，降低MOS mRNA的稳定性。结果表明，除了转录激活外，mRNA稳定化是IL-1 β刺激β细胞中MOS表达的机制的关键组成部分，并且PKC δ在该过程中起重要作用。因此，当β-细胞暴露于IL-1 β和潜在的其它细胞因子时，PKC δ活化可能对细胞功能和生存力具有显著的影响。
Exposure of pancreatic islets to cytokines such as interleukin (IL)-1 beta induces a variety of proinflammatory genes including type II nitric-oxide synthase (MOS) which produces nitric oxide (NO). NO is thought to be a major cause of islet beta -cell dysfunction and apoptotic beta -cell death, which results in type I diabetes. Since protein kinase C (PKC) mediates some of the actions of cytokines in other cell types, our aim was to assess the role of PKC in IL-1 beta -induced iNOS expression in pancreatic beta -cells. PKC delta, but not PKC alpha, was specifically activated in the rat INS-1 beta -cell line by IL-1 beta as assessed by membrane translocation. Moreover, MOS expression and NO production were significantly attenuated by the PKC delta specific inhibitor rottlerin and overexpression of a PKC delta kinase-dead mutant protein. Conversely, overexpression of PKC delta wild type protein significantly potentiated this response. These results were confirmed at the mRNA level by reverse transcriptase-polymerase chain reaction. However, a role at the level of transcriptional regulation appeared unlikely, since PKC delta was not required for the activation of NF-kappaB, activating protein 1, and activating transcription factor 2 signaling pathways in response to IL-1 beta. There was, however, a significant increase in MOS mRNA stability mediated by PKC delta wild type, while PKC delta kinase-dead acted reciprocally, reducing MOS mRNA stability. The results indicate that, in addition to transcriptional activation, mRNA stabilization is a key component of the mechanism by which IL-1 beta stimulates MOS expression in beta -cells and that PKC delta plays an essential role in this process. PKC delta activation may therefore have significant consequences with regard to cellular function and viability when beta -cells are exposed to IL-1 beta and potentially other cytokines.