Overexpression p21WAF1/CIP1 in suppressing retinal pigment epithelial cells and progression of proliferative vitreoretinopathy via inhibition CDK2 and cyclin E.

Ying Wang,Jindong Han,Zhigang Yuan,Haiyan Li,Hua Yan,Caiyun You,Zhuhong Zhang

doi:10.1186/1471-2415-14-144

Abstract

BackgroundP21 is one kind of cyclin-dependent kinase inhibitor that can prevent cells from going through the G1/S phase checkpoint and inhibit cell proliferation. Proliferative vitreoretinopathy (PVR) is a proliferative response in the eye. The aim of this study was to determine whether p21Waf1/Cip1 (p21) suppresses the proliferation and migration of retinal pigment epithelial (RPE) cells in vitro and controls PVR development in vivo.MethodsCell cycle analyses and transwell assays were conducted to assess cell proliferation characteristics and the migration ability of RPE cells after transfection with p21. Western blot and reverse-transcription polymerase chain reaction technologies were used to detect the expression of p21, CDK2 and cyclinE in RPE cells and rabbit retinal tissues. The impact of increasing p21 expression on PVR development was conducted by implantation of an adenovirus vector containing rabbit p21 (rAd-p21) in a PVR rabbit model. The prevalence of PVR and retinal detachment was determined by indirect ophthalmoscopy on days 3, 7, 14, and 21 after the injection of rAd-p21 into the vitreous. B scans and hematoxylin-eosin staining were employed to check rabbit retinas on day 21.ResultsCell cycle analyses and transwell assays showed that p21 inhibited the proliferation and migration of RPE cells. Increased expression of p21 was detected in cultured RPE cells and rabbit retinas after transfection with the p21 gene, whereas levels of CDK2 and cyclinE were decreased. The increase in p21 expression effectively suppressed the development of PVR in a rabbit model.ConclusionsThe increase in p21 expression in RPE cells not only inhibits the proliferation and migration of RPE cells in vitro, but also suppresses the development of PVR in vivo, which indicates its therapeutic potential in treating PVR.

Highlights

P21 is one kind of cyclin-dependent kinase inhibitor that can prevent cells from going through the G1/S phase checkpoint and inhibit cell proliferation
The p21 protein belongs to the family of cyclindependent kinase inhibitors (CDKIs), which play an important role in the regulation of cell cycle progression [3]
To determine whether p21 inhibits the proliferation of retinal pigment epithelial (RPE) cells, we performed flow cytometry to analyze the cell cycle progression

Summary

Introduction

P21 is one kind of cyclin-dependent kinase inhibitor that can prevent cells from going through the G1/S phase checkpoint and inhibit cell proliferation. The aim of this study was to determine whether p21Waf1/Cip (p21) suppresses the proliferation and migration of retinal pigment epithelial (RPE) cells in vitro and controls PVR development in vivo. Proliferative vitreoretinopathy (PVR) is characterized by the migration and proliferation of cells following a break in the retina or trauma, leading to formation of periretinal membranes, followed by contraction of cellular membranes and traction on the retina that causes retinal detachment. The p21 protein belongs to the family of cyclindependent kinase inhibitors (CDKIs), which play an important role in the regulation of cell cycle progression [3]. Up-regulation of p21 expression and other CDKIs results in activation of suppression molecules of CDKs and cyclinE, allowing accumulation of hypophosphorylated Rb and cell cycle arrest in the G1 phase [4,5]. A previous study has shown that an increase in p21 by subconjunctival injection of the recombinant adenovirus vector-mediated p21 gene inhibits fibroproliferation and wound healing in a rabbit model of glaucoma filtration surgery [8]

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