Ohnishi Masayoshi, Hasegawa Goji, Yamasaki Masahiro, Obayashi Hiroshi, Fukui Michiaki, Nakajima Toshiki, Ichida Yukiko, Ohse Hiroyuki, Mogami Shin-ichi, Yoshikawa Toshikazu, Nakamura Naoto
Department of Endocrinology and Metabolism, Kyoto Prefectural University of Medicine, Graduate School of Medical Science, 465 Kajii-cho, Hirokoji, Kawaramachi-dori, Kamikyo-ku, Kyoto 602-8566, Japan.
Nephrol Dial Transplant. 2006 Jul;21(7):1786-93. doi: 10.1093/ndt/gfl120. Epub 2006 Apr 12.
Integrin-linked kinase (ILK) is a protein that plays an important role in extracellular matrix-mediated signalling. Recent studies implicated ILK dysregulation in the development of diabetic nephropathy. However, little is known about the significance of ILK up-regulation in response to high glucose in mesangial cells.
The ILK messenger (m)RNA and protein expression in human mesangial cells were analysed with quantitative real-time polymerase chain reaction (PCR) and western blotting after exposure to either 100, 200, or 500 mg/dl glucose, or 100 mg/dl glucose + 400 mg/dl mannitol. Activation of protein Kinase B (PKB)/Akt was also determined by western blot analysis. Cells were transfected with ILK siRNA to determine the effects of ILK knockdown on PKB/Akt activation and cell death following treatment with high glucose or mannitol.
High concentrations of glucose or mannitol for three days significantly up-regulated ILK mRNA and protein expression (P < 0.05 vs 100 mg/dl glucose). In contrast, ILK expression in cells exposed to the same conditions for seven days was unaffected. The time course of PKB/Akt phosphorylation was similar to that of ILK protein expression. The siRNA-mediated down-regulation of ILK expression inhibited the elevation of PKB/Akt phosphorylation induced by high glucose treatment. Furthermore, the inhibition of ILK expression promoted high glucose- or mannitol-induced apoptosis.
The ILK may act as a pro-survival factor and play a role in protecting mesangial cells from hyperglycaemic osmotic stress.
整合素连接激酶（ILK）是一种在细胞外基质介导的信号传导中起重要作用的蛋白质。最近的研究表明ILK失调与糖尿病肾病的发生发展有关。然而，关于系膜细胞中高糖诱导的ILK上调的意义知之甚少。
将人系膜细胞暴露于100、200或500mg/dl葡萄糖或100mg/dl葡萄糖+400mg/dl甘露醇后，采用定量实时聚合酶链反应（PCR）和蛋白质印迹法分析ILK信使（m）RNA和蛋白质表达。还通过蛋白质印迹分析确定蛋白激酶B（PKB）/Akt的激活情况。用ILK小干扰RNA（siRNA）转染细胞，以确定ILK敲低对高糖或甘露醇处理后PKB/Akt激活和细胞死亡的影响。
高浓度葡萄糖或甘露醇处理三天显著上调ILK mRNA和蛋白质表达（与100mg/dl葡萄糖相比，P<0.05）。相反，在相同条件下处理七天的细胞中ILK表达未受影响。PKB/Akt磷酸化的时间进程与ILK蛋白表达相似。siRNA介导的ILK表达下调抑制了高糖处理诱导的PKB/Akt磷酸化升高。此外，抑制ILK表达促进了高糖或甘露醇诱导的细胞凋亡。
ILK可能作为一种促生存因子，在保护系膜细胞免受高血糖渗透应激方面发挥作用。
