Elevated tropomyosin expression is associated with epithelial–mesenchymal transition of lens epithelial cells

Journal of Cellular and Molecular Medicine

Eri Kubo²  Nailia Hasanova²  Nigar Fatma¹  Hiroshi Sasaki² 

[1] Department of Ophthalmology and Visual Sciences, University of Nebraska Medical Center, Omaha, NE, USA;Department of Ophthalmology, Kanazawa Medical University, Ishikawa, Japan

关键词: epithelial–mesenchymal transition;    tropomyosin;    lens;    posterior capsule opacity;    anterior subcapsular fibrosis;    cataract;   

DOI  :  10.1111/j.1582-4934.2012.01654.x

来源: Wiley

【 摘 要 】

Abstract

Injury to lens epithelial cells (LECs) leads to epithelial–mesenchymal transition (EMT) with resultant fibrosis. The tropomyosin (Tpm) family of cytoskeleton proteins is involved in regulating and stabilizing actin microfilaments. Aberrant expression of Tpms leads to abnormal morphological changes with disintegration of epithelial integrity. The EMT of LECs has been proposed as a major cause of posterior capsule opacification (PCO) after cataract surgery. Using in vivo rodent PCO and human cataractous LECs, we demonstrated that the aberrant expression of rat Tpm and human Tpm1α/2β suggested their association in remodelling of the actin cytoskeleton during EMT of LECs. Expression analysis from abnormally growing LECs after lens extraction revealed elevated expression of α-smooth muscle actin (α-SMA), a marker for EMT. Importantly, these cells displayed increased expression of Tpm1α/2β following EMT/PCO formation. Expression of Tpm1α/2β was up-regulated in LECs isolated from cataractous lenses of Shumiya Cataract Rats (SCRs), compared with non-cataractous lenses. Also, LECs from human patients with nuclear cataract and anterior subcapsular fibrosis (ASF) displayed significantly increased expression of Tpm2β mRNA, suggesting that similar signalling invokes the expression of these molecules in LECs of cataractous SCR and human lenses. EMT was observed in LECs overexpressed with Tpm1α/2β, as evidenced by increased expression of α-SMA. These conditions were correlated with remodelling of actin filaments, possibly leading to EMT/PCO and ASF. The present findings may help clarify the condition of the actin cytoskeleton during morphogenetic EMT, and may contribute to development of Tpm-based inhibitors for postponing PCO and cataractogenesis.

【 授权许可】

CC BY   
© 2012 The Authors Journal of Cellular and Molecular Medicine Published by Foundation for Cellular and Molecular Medicine/Blackwell Publishing Ltd

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