Increased levels of serum pigment epithelium-derived factor aggravate proteinuria via induction of podocyte actin rearrangement.
Int Urol Nephrol 2018;
51:359-367. [PMID:
30536192 PMCID:
PMC6394770 DOI:
10.1007/s11255-018-2026-3]
[Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2018] [Accepted: 11/03/2018] [Indexed: 10/27/2022]
Abstract
PURPOSE
To assess the role of serum pigment epithelium-derived factor (PEDF) in the occurrence and development of proteinuria and renal dysfunction and determine its relevant signaling pathway.
METHODS
We analyzed serum PEDF, creatinine, the urinary albumin-to-creatinine ratio, and renal morphology of normal or streptozotocin (STZ)-induced diabetic mice, before and after treatment with PEDF. In vitro, podocytes were stimulated with PEDF under normal or high-glucose conditions; permeability was measured by the transwell assay with fluorescein isothiocyanate (FITC)-dextran; and F-actin cytoskeleton was analyzed by phalloidin staining. Apoptosis was assessed by flow cytometry. RhoA activity and ROCK1, ZO-1, nephrin, and podocin levels were detected by Western blotting.
RESULTS
Diabetic mice exhibited a high serum PEDF level. In vivo, elevated serum PEDF led to proteinuria, increased serum creatinine, and podocyte foot process fusion in normal or diabetic mice. In vitro, both high-glucose and PEDF stimulation activated the RhoA/ROCK1 pathway in podocytes and promoted cell permeability, F-actin rearrangement, and apoptosis. Inhibition of RhoA/ROCK1 alleviated the damage from these effects.
CONCLUSIONS
Elevated serum PEDF aggravates the development of proteinuria and renal dysfunction by inducing F-actin arrangement, foot process fusion, and apoptosis of podocytes in both normal and diabetic mice, and this effect may be mediated by activation of the RhoA/ROCK1 pathway.
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