Different alpha crystallin expression in human age-related and congenital cataract lens epithelium.

Jing Yang,Minfei Guo,Yuting Li,Sheng Zhou,Jianjun Gu

doi:10.1186/s12886-016-0241-1

Abstract

BackgroundThe purpose of this study was to investigate the different expressions of αA-crystallin and αB-crystallin in human lens epithelium of age-related and congenital cataracts.MethodsThe central part of the human anterior lens capsule approximately 5 mm in diameter together with the adhering epithelial cells, were harvested and processed within 6 hours after cataract surgery from age-related and congenital cataract patients or from normal eyes of fresh cadavers. The mRNA and soluble protein levels of αA-crystallin and αB-crystallin in the human lens epithelium were detected by real-time PCR and western blots, respectively.ResultsThe mRNA and soluble protein expressions of αA-crystallin and αB-crystallin in the lens epithelium were both reduced in age-related and congenital cataract groups when compared with the normal control group. However, the degree of α-crystallin loss in the lens epithelium was highly correlated with different cataract types. The α-crystallin expression of the lens epithelium was greatly reduced in the congenital cataract group but only moderately decreased in the age-related cataract group. The reduction of αA-crystallin soluble protein levels in the congenital cataract group was approximately 2.4 fold decrease compared with that of the age-related cataract group, while an mRNA fold change of 1.67 decrease was observed for the age-related cataract group. Similarly, the reduction of soluble protein levels of αB-crystallin in the congenital cataract group was approximately a 1.57 fold change compared with that of the age-related cataract group. A 1.75 fold change for mRNA levels compared with that of the age-related cataract group was observed.ConclusionsThe results suggest that the differential loss of α-crystallin in the human lens epithelium could be associated with the different mechanisms of cataractogenesis in age-related versus congenital cataracts, subsequently resulting in different clinical presentations.

Highlights

The purpose of this study was to investigate the different expressions of αA-crystallin and αB-crystallin in human lens epithelium of age-related and congenital cataracts
The results suggest that the different clinical appearances of age-related and congenital cataracts are linked to variant αA-crystallin and αBcrystallin expressions in the lens epithelium
Both αAcrystallin and αB-crystallin expression levels were significantly reduced in the age-related and congenital cataract groups compared with the normal control group

Summary

Introduction

The purpose of this study was to investigate the different expressions of αA-crystallin and αB-crystallin in human lens epithelium of age-related and congenital cataracts. Cataract is one of the main causes of blindness and can be congenital or acquired [1]. In developed and developing countries, the age-related cataracts occupy the leading reason of blindness [2,3,4]. Compared with the age-related cataracts, congenital cataracts have much less morbidity, but they are still responsible for 10 %–30 % of blindness cases in children all over the world [5]. Human lens proteins are mainly composed of α-, β- and γ-crystallins. In addition to the structural role, α-crystallin functions as a chaperone for maintenance of lens transparency [10,11,12].

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