Basic Study
High uric acid induces phenotypic transition of renal tubular cells via PI3K/Akt signaling pathway
Xiaoyan Xiong, Shoujun Bai, Yakun Wang, Tingting Ji, Hongxiu Du, Xiaoying Li, Congpu Gao, Juan Liu, Yingchun Zhu, Fangfang Zha
Published 2018-02-15
Cite as Chin J Nephrol, 2018, 34(2): 130-135. DOI: 10.3760/cma.j.issn.1001-7097.2018.02.008
Abstract
ObjectiveTo investigate the effect and the mechanism of epithelial-mesenchymal transition (EMT) in renal tubular cells induced by uric acid.
MethodsNormal rat kidney tubular cell line (NRK-52E) were exposed to different concentrations of uric acid (100, 200, 400, 600, 800 μmol/L UA) for 48 hours to induce EMT. Morphological changes of the NRK-52E cells were examined under an inverted phase contrast microscope. The protein expression of E-cadherin, α-SMA, p-Akt and Akt were detected by Western blotting. The distribution of E-cadherin and α-SMA were detected by immunofluorescence. NRK-52E cells were pretreated by different concentrations of LY294002(0, 2.5, 5, 10, 15 μmol/L), the inhibitor of PI3K/p-Akt signaling pathway, and then processed by uric acid (400 μmol/L) for 48 hours. Western blotting was used to detect the protein expression of p-Akt and Akt. NRK-52E cells were then divided into four groups: normal group (N), uric acid group (UA), LY294002 group (LY), uric acid with LY294002 group (UA+LY). The protein expression of E-cadherin and α-SMA were detected by Western blotting, the distribution of E-cadherin, α-SMA and p-Akt were detected by immunofluorescence.
ResultsThere was abundant cellular expression of E-cadherin in unstimulated renal tubular cells whereas its expression was significantly decreased in uric acid-stimulated cells (P<0.05). In addition, uric acid induced de novo expression of α-SMA in contrast to almost negative staining in untreated cells (P<0.05). p-Akt were obviously increased in high uric acid group (P<0.05) and Akt changed not significantly (P>0.05). NRK-52E cells transformed into elongated fibroblast-like cells from cuboidal clustered epithelial cells. These indicated that uric acid has induced EMT and activated PI3K/p-Akt signaling pathway in NRK-52E cells. However, the above effects of uric acid were abolished when p-Akt was blocked by the PI3K inhibitor (10, 15 μmol/L LY294002), indicated that LY294002 has reversed the trend of EMT.
ConclusionsHigh uric acid induces phenotypic transition of renal tubular cells probably via activating PI3K/Akt signaling pathway.
Key words:
Uric acid; Kidney tubules; Epithelial cells; Epithelial-mesenchymal transition; PI3K/Akt
Contributor Information
Xiaoyan Xiong
Department of Nephrology, Zhongshan Hospital Qingpu Branch, Fudan University, Shanghai 201700, China
Shoujun Bai
Yakun Wang
Tingting Ji
Hongxiu Du
Xiaoying Li
Congpu Gao
Juan Liu
Yingchun Zhu
Fangfang Zha
