Effect of KLF-4 on peritoneal fibrosis induced by high glucose peritoneal dialysate via targeting regulation of the expression of E-cadherin / 解放军医学杂志

ABSTRACT

[Abstract] Objective To explore the relationship between Kruppel-like factor 4 (KLF-4) and E-cadherin in human peritoneal mesothelial cells (HPMCs), and the expression and function of KLF-4 in the animal model of peritoneal fibrosis induced by high glucose peritoneal dialysate. Methods Co-transfection in HPMCs with the plasmid of KLF-4 and the bind site or mutant in the promoter region of E-cadherin, and then the luciferase activity was measured of the each bind site and its matched mutants to estimate whether KLF-4 can combine with the bind site in the promoter region of E-cadherin; Chromatin immunocoprecipitation (CHIP) was exploited to verify if KLF-4 can combine with the bind site in the promoter region of E-cadherin; Real-time PCR and Western blotting were performed to detect the expression of E-cadherin at the bind site and matched mutants of b, d, f and g. Thirty SD rats were randomly divided into saline group, peritoneal dialysate group and experimental group (10 each). Rats in saline group were given intraperitoneal injection with 0.9% NaCl, in peritoneal dialysate group were given with 4.25% high glucose peritoneal dialysate, and in experimental group were given via tail vein with 4.25% high glucose peritoneal dialysate and the mixture of KLF-4 plasmid suspension containing ultrasound microbubble. To observe the peritoneal tissue thickness of the 3 groups of rats by Hematoxylin and Eosin staining. Masson trichrome staining was performed to detect the deposition of collagen fibers in peritoneal tissue of the 3 groups of rats. Immunohistochemistry was used to detect the expression level of KLF-4, E-cadherin, α-SMA and fibronectin (FN) in peritoneal tissue of the 3 groups of rats. Results Promoter luciferase reporter gene and CHIP results showed that KLF-4 can combine with the bind site in the promoter region of E-cadherin in HPMCs. Real-time PCR and Western blotting showed that KLF-4 can positively regulate the expression of E-cadherin. HE staining showed that the peritoneal tissue was obviously thickened in rats of peritoneal dialysate group [(105.91±12.0) μm] than in rats of saline group [(20.89±5.39) μm] and of experimental group [(23.05±6.07) μm] with statistical significance (P0.05). Masson staining showed that the deposition of collagen fiber significantly increased in peritoneal dialysate group (0.89±0.09) than in saline group (0.19±0.03) and experimental group (0.15±0.06) with statistical significance (P0.05). Immunohistochemistry results showed that the expressions of KLF-4 and E-cadherin were obviously lower in peritoneal dialysate group (0.27±0.09, 0.31±0.03) than in saline group (0.79±0.19, 0.83±0.13) and experimental group (0.85±0.11, 0.76±0.11) with statistically significant difference (P0.05). In contrast, the expressions of α-SMA and FN were evidently higher in peritoneal dialysate group (0.83±0.09, 0.63±0.09) than in saline group (0.22±0.08, 0.30±0.07) and experimental group (0.19±0.05, 0.11±0.03) with statistically significant difference (P0.05). Conclusion KLF-4 may positive regulate the expression of E-cadherin by combining with the bind site in the promoter region of E-cadherin, and inhibit the peritoneal fibrosis induced via high glucose peritoneal dialysate.