| ObjectiveCataract is a frequently occurring eye disease mainly leading to blindness in the world,which is associated with complicated pathogenesis.Its molecular mechanism of genesis has long been the research hotspot.The lens has pure cellular component with no blood supply,which is constituted by lens capsular,lens epithelial cell and the lens fiber finally formed through differentiation.Recent research discovers that,bone morphogenetic protein(BMP)is abundantly expressed in eye tissue;particularly,it plays a vital role during the development of lens [1].Additionally,research has indicated the expression of BMPs and their receptors BMPR IA and BMPR II during the genesis and development of rat lens.Mouse knocked out of BMP I receptor Acvr1 has smaller lens morphology than normal [3].Target BMP-7 gene deletion or inactivation in mouse embryo will not only affect the normal development of embryonic lens vesicle and lens plate,but also impact the normal development of optic vesicle and ectoblast,while the latter is essential to the formation of lens [2].Nevertheless,whether BMPs signal is involved in the genesis of lens disease after the mature development of lens remains unclear in existing studies.Plenty existing studies on the pathogenesis of cataract suggest that,the genesis of cataract is related to oxidative damage,production of free radicals,changes of crystal proteins and apoptosis of human lens epithelial cells(HLECs).Therefore,this project aimed to explore whether BMPs playing important roles during lens development could regulate HLECs and crystallin(CRY)during the mature development of lens and thus the genesis of cataract.This project has investigated the characteristics of the expression of BMPs in human lens and the effects of the BMPs on HLECs under normal condition and stress state,aiming to explor the mechanisms of action of BMPs on HLECs in order to provide a new thinking and theoretical foundation for the molecular mechanism of cataract genesis.Methods 1.The capsule,cortex and nucleus of the cloudy lens from patient with cataract were adopted to detect BMP-4 and BMP-7 expression in capsular through immunohistochemical staining,while that in cortex and nucleus was detected using Enzyme-Linked Immunosorbnent Assay(ELISA).Moreover,the differentiated expression profiles of BMP-4 and BMP-7 in different parts of lens tissues in patient with cataract were observed.2.Human lens epithelial cell line HLEB-3 was cultured in vitro,and the effects of BMP-4 and BMP-7 on human lens epithelial cells were detected using CCK-8 and cell wound scratch assay.3.Human lens epithelial cell line HLEB-3 was cultured in vitro,and the oxidative stress(thermal stimulus,ultraviolet irradiation,and hydrogen peroxide)cell model was constructed.Meanwhile,the effects of BMP-4 and BMP-7 on the proliferation and apoptosis of human lens epithelial cells were detected using CCK-8.Besides,the expression of Caspase-3 apoptin as well as the reactive oxygen species(ROS)was also detected.4.Moreover,the effects of BMP-4 and BMP-7 on the oxidative stress-induced apoptosis of lens epithelial cells,as well as its relationship with endoplasmic reticulum stress,were detected using RT-PCR and immunofluorescence.Results 1.The expression of BMP-4 and BMP-7 was varied in different part of the lens in patients with age-related cataract,and it was decreased from cortex to nucleus.2.BMP-4 and BMP-7 showed no obvious effects on the proliferation of lens epithelial cells,but could markedly suppress the migration of human lens epithelial cells.3.Under oxidative stress s,BMP-4 and BMP-7 could evidently suppress the apoptosis of human lens epithelial cells,and reduce the expression of Caspase-3 and ROS.4.Under oxidative stress stimulation,human lens epithelial cells can induce the endoplasmic reticulum stress cascade reaction in the ATF-6 pathway,which resulted in apoptosis.Both BMP-4 and BMP-7 could effectively suppress the ATF-6 gene expression level to exert their protective effects. |
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