Long Noncoding RNA NEAT1 Regulates TGF-β2-Induced Epithelial-Mesenchymal Transition of Lens Epithelial Cells through the miR-34a/Snail1 and miR-204/Zeb1 Pathways.

Ning Dong

doi:10.1155/2020/8352579

Abstract

The aim of this study was to explore whether the long noncoding RNA nuclear paraspeckle assembly transcript 1 (NEAT1)/miR-34a/Snail1 and NEAT1/miR-204/Zeb1 pathways are involved in epithelial-mesenchymal transition (EMT) of lens epithelial cells (LECs). Primary human LECs (HLECs) were separated and cultured. Our results identified that TGF-β2 induces NEAT1 overexpression in a dose-dependent manner and a time-dependent manner. Additionally, TGF-β2 induced downregulation of E-cadherin and upregulation of fibronectin in primary HLECs through a NEAT1-dependent mechanism. Microarray analysis showed that NEAT1 overexpression inhibited the miR-34a and miR-204 levels in the LECs. The expression of miR-34a and miR-204 was decreased, and the levels of Snail1 and Zeb1 were elevated in human posterior capsule opacification- (PCO-) attached LECs and the LECs obtained from anterior subcapsular cataract (ASC) by quantitative RT-PCR (qRT-PCR). Mechanistic studies revealed that NEAT1 negatively regulates miR-34a or miR-204, and miR-34a or miR-204 directly targets Snail1 or Zeb1 by luciferase assay and RNA-binding protein immunoprecipitation assay, respectively. Overall, the NEAT1/miR-34a/Snail1 and NEAT1/miR-204/Zeb1 pathways are involved in TGF-β2-induced EMT of HLECs. In summary, TGF-β2 induces NEAT1 overexpression, which in turn suggests that NEAT1 acts as a ceRNA targeting Snail1 or Zeb1 by binding miR-34a or miR-204, and promotes the progression of EMT of LECs.

Highlights

Cataract is a leading cause of visual impairment and blindness globally [1, 2]
Our previous studies have identified that nuclear paraspeckle assembly transcript 1 (NEAT1) expression was upregulated in human posterior capsule opacification- (PCO-)attached lens epithelial cells (LECs) compared with normal-attached LECs and increased in LECs obtained from patients with anterior subcapsular cataract (ASC) compared with nuclear cataracts [6]
The expression of NEAT1 was increased in primary human LECs (HLECs) treated with TGF-β2 in a dose-dependent manner and a time-dependent manner (Figures 1(a) and 1(b)). quantitative RT-PCR (qRT-PCR) confirmed the efficiency of NEAT1 knockdown using siNEAT1-1 or siNEAT1-2 (Figure 1(c))

Summary

Introduction

Cataract is a leading cause of visual impairment and blindness globally [1, 2]. It is treatable only by surgical replacement of the cataractous lens fiber mass with an artificial intraocular lens (IOL), which has placed a huge health burden [1, 2]. Accumulating evidence shows EMT plays an important role in the pathogenesis of PCO [5, 6]. During this transition, residual LECs lose polarity and cell-cell adhesion and transdifferentiate into mesenchyme-like cells [1,2,3,4,5,6]

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