Possible role of HIWI2 in modulating tight junction proteins in retinal pigment epithelial cells through Akt signaling pathway

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• 作者：Suganya Sivagurunathan ; Karthikka Palanisamy…
• 关键词：PIWIL proteins ; Retinal pigment epithelium ; HIWI2 ; Tight junctions ; Akt pathway
• 刊名：Molecular and Cellular Biochemistry
• 出版年：2017
• 出版时间：March 2017
• 年：2017
• 卷：427
• 期：1-2
• 页码：145-156
• 全文大小：
• 刊物类别：Biomedical and Life Sciences
• 刊物主题：Biochemistry, general; Medical Biochemistry; Oncology; Cardiology;
• 出版者：Springer US
• ISSN：1573-4919
• 卷排序：427

文摘

PIWI subfamily of proteins is shown to be primarily expressed in germline cells. They maintain the genomic integrity by silencing the transposable elements. Although the role of PIWI proteins in germ cells has been documented, their presence and function in somatic cells remains unclear. Intriguingly, we detected all four members of PIWI-like proteins in human ocular tissues and somatic cell lines. When HIWI2 was knocked down in retinal pigment epithelial cells, the typical honeycomb morphology was affected. Further analysis showed that the expression of tight junction (TJ) proteins, CLDN1, and TJP1 were altered in HIWI2 knockdown. Moreover, confocal imaging revealed disrupted TJP1 assembly at the TJ. Previous studies report the role of GSK3β in regulating TJ proteins. Accordingly, phospho-kinase proteome profiler array indicated increased phosphorylation of Akt and GSK3α/β in HIWI2 knockdown, suggesting that HIWI2 might affect TJ proteins through Akt-GSK3α/β signaling axis. Moreover, treating the HIWI2 knockdown cells with wortmannin increased the levels of TJP1 and CLDN1. Taken together, our study demonstrates the presence of PIWI-like proteins in somatic cells and the possible role of HIWI2 in preserving the functional integrity of epithelial cells probably by modulating the phosphorylation status of Akt.