Interaction between PKR and PACT mediated by LPS-inducible NF-κB in human gingival cells
Interaction between PKR and PACT mediated by LPS-inducible NF-κB in human gingival cells
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LPS诱导的NF-κB在人牙龈细胞中介导的PKR和PACT之间的相互作用
DOI：
10.1002/jcb.23340
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
Yoshida H
中科院分区：
文献类型：
--
作者：
Yoshida K;Okamura H;Hoshino Y;Shono H;Yoshioka M;Hinode D;Yoshida H
双链RNA依赖性蛋白激酶（PKR）是一种在哺乳动物细胞中组成型表达的丝氨酸/苏氨酸激酶。PKR在病毒感染后被双链RNA（dsRNA）激活，并在宿主抗病毒防御机制中起关键作用。PKR还已知调节各种生物反应，包括细胞分化和凋亡。然而，PKR是否参与牙周炎的进展尚不清楚。本研究解释了磷酸化PKR的LPS在人牙龈细胞系，Sa 3。在Sa 3细胞中检测到编码LPS受体的基因的表达，并且用1 μg/mL LPS处理细胞6小时引起PKR磷酸化。LPS刺激后3 h内PKR蛋白激活因子（PACT）mRNA和蛋白表达增加，PACT与PKR的结合增强。LPS处理30 min后，NF-κB转位至细胞核，抑制NF-κB可降低LPS诱导的PACT-PKR相互作用。促炎细胞因子mRNA水平，包括白细胞介素-6（IL-6）和肿瘤坏死因子α（TNFα），在加入LPS后45 min内出现，并在90 min达到最高水平。这种促炎细胞因子的诱导不受RNAi介导的PKR沉默和PKR的药理学抑制剂的影响，而NF-κB的抑制则使其降低。这些结果表明，LPS诱导了Sa 3细胞中PKR磷酸化和PACT-PKR的缔合。我们的研究结果还表明，NF-κB参与了牙周炎中PACT-PKR的相互作用和促炎细胞因子的产生。J.细胞。113：165-173，2012.© 2011 Wiley Periodicals，Inc.
The double‐stranded RNA‐dependent protein kinase (PKR) is a serine/threonine kinase expressed constitutively in mammalian cells. PKR is activated upon virus infection by double‐stranded RNA (dsRNA), and plays a critical role in host antiviral defense mechanisms. PKR is also known to regulate various biological responses, including cell differentiation and apoptosis. However, whether PKR is involved in the progress of periodontitis is not clear. The present study explained the phosphorylation of PKR by LPS in the human gingival cell line, Sa3. Expression of genes encoding LPS receptors was detected in Sa3 cells and treatment of cells with 1 µg/mL LPS for 6 h caused PKR phosphorylation. LPS elevated the expression of the protein activator of PKR (PACT) mRNA and protein, followed by the enhanced association between PACT and PKR within 3 h. In addition, LPS treatment induced the translocation of NF‐κB to the nucleus after 30 min, and inhibition of NF‐κB decreased the PACT–PKR interaction induced by LPS. The level of pro‐inflammatory cytokine mRNA, including interleukin‐6 (IL‐6) and tumor necrosis factor alpha (TNFα), appeared within 45 min and reached at the maximal levels by 90 min after the addition of LPS. This induction of pro‐inflammatory cytokines was not affected by RNAi‐mediated silencing of PKR and a pharmacological inhibitor of PKR, whereas the inhibition of NF‐κB decreased it. These results indicated that LPS induces PKR phosphorylation and the PACT–PKR association in Sa3 cells. Our results also suggest that NF‐κB is involved in the PACT–PKR interaction and the production of pro‐inflammatory cytokines in periodontitis. J. Cell. Biochem. 113: 165–173, 2012. © 2011 Wiley Periodicals, Inc.