Visfatin Reduces Gap Junction Mediated Cell-to-Cell Communication in Proximal Tubule-Derived Epithelial Cells

Cellular Physiology and Biochemistry

关键词: Gap Junctions;    Proximal Tubule;    Transforming Growth Factor Beta1;    Diabetic Nephropathy;    Visfatin;   

DOI  :  10.1159/000354519

学科分类：分子生物学，细胞生物学和基因

来源: S Karger AG

【 摘 要 】

Background/Aims In the current study we examined if the adipocytokine, visfatin, alters connexin-mediated intercellular communication in proximal tubule-derived epithelial cells. Methods The effects of visfatin (10-200ng/mL) on cell viability and cytotoxicity in HK2-cells were assessed by MTT, crystal violet and lactate dehydrogenase assays. Western blot analysis was used to confirm expression of Cx26, Cx40 and Cx43. The effect of visfatin (10-200ng/mL) on TGF-β1 secretion was confirmed by ELISA, and the effects of both TGF-β1 (2-10ng/mL) and visfatin (10-200ng/mL) on connexin expression were assessed by western blot. Functional intercellular communication was determined using transfer of Lucifer Yellow and paired-whole cell patch clamp electrophysiology. Results In low glucose (5mM), visfatin (10-200ng/mL) did not affect membrane integrity, cytotoxicity or cell viability at 48hrs, but did evoke a concentration-dependent reduction in Cx26 and Cx43 expression. The expression of Cx40 was unaffected. At 48hrs, visfatin (10-200ng/mL) increased the secretion of TGF-β1 and the visfatin-evoked changes in connexin expression were mimicked by exogenous application of the pro-fibrotic cytokine (2-10ng/ml). Visfatin reduced dye transfer between coupled cells and decreased functional conductance, with levels falling by 63% as compared to control. Although input resistance was increased following visfatin treatment by 166%, the change was not significant as compared to control. The effects of visfatin on Cx-expression and cell-coupling were blocked in the presence of a TGF-β1 specific neutralizing antibody. Conclusions The adipocytokine visfatin selectively evoked a non-toxic reduction in connexin expression in HK2-cells. The loss in gap-junction associated proteins was mirrored by a loss in functional conductance between coupled cells. Visfatin increased TGF-β secretion and the pattern of change for connexins expression was mimicked by exogenous application of TGF-β1. The effect of visfatin on Cx-expression and dye transfer were negated in the presence of a TGF-β1 neutralising antibody. These data suggest that visfatin reduces connexin-mediated intercellular communication in proximal tubule-derived epithelial cells via a TGF-β dependent pathway.

【 授权许可】

CC BY-NC-ND