The expression and function of double-stranded RNA-dependent protein kinase (PKR) in rat intestinal epithelial cells

肠道上皮细胞(IECs)暴露在微生物和病毒产品中，是它们的基本屏障。鉴于双链RNA依赖蛋白激酶(PKR)参与细胞抗病毒反应、细胞分化和细胞凋亡，我们试图研究PKR在大鼠IECS中的表达及其作用。在本研究中，我们发现了PKR在成年大鼠IECs中的表达。我们还证明在培养的大鼠IECs中有PKR的表达。培养的IECs中PKR蛋白表达水平和碱性磷酸酶(ALP)活性呈时间依赖性增加。用PKR抑制剂处理后，IECS内ALP活性降低。加入人工合成的双链RNA以剂量依赖的方式诱导这些细胞的凋亡。氢化可的松也抑制了这些细胞中PKR的表达。因此，我们认为PKR在IECS中的表达是对抗原的有效屏障，并且可能是大鼠IECS分化和凋亡的调节因子。

Intestinal epithelial cells (IECs) are exposed to microbial and viral products, and serve as essential barriers to them. Since double-stranded RNA-dependent protein kinase (PKR) is involved in cellular antiviral response, cell differentiation and apoptosis, we tried to investigate the expression and roles of PKR in rat IECs. In this study, we showed that the expression of PKR in IECs of adult rats. We also demonstrated that PKR was expressed in cultured rat IECs. The level of PKR protein expression and the activity of alkaline phosphatase (ALP) increased in the cultured IECs in a time-dependent manner. Treatment with PKR inhibitor decreased ALP activity in the IECs. The addition of synthetic double-stranded RNA induced apoptosis in a dose-dependent manner in these cells. Treatment with hydrocortisone also provoked suppression of PKR expression in such cells. Thus, we concluded that PKR is expressed in IECs as potent barriers to antigens and is a possible modulator of the differentiation and apoptosis in rat IECs.