Abstract
Purpose :
Heat shock proteins play important roles in mediating cellular stress responses and protect the internal milieus against damage. Changes in the expression levels of these proteins are often related to various human diseases. In the present study, we have analyzed different heat shock proteins including HSP90, HSP70, HSP60 and HSP40 in human normal and cataractous lenses of different age groups (from 50 years old to 89 years old).
Methods :
Normal human lenses of 50 and 60 years old, and cataractous lenses of different age groups (from 50 years old to 89 years old) were used as material. Mouse lens epithelial cell line, aTN4-1 cells were used to knockdown HSP90 through CRISPR/Cas9 technology. Automated western immunoblotting was used to analyze the changes of different heat shock proteins in normal or cataractous lenses. CellTiter-Glo® luminescent cell viability assay and live/dead assay were used to detect apoptosis. ChIP and EMSA were used to analyze HSF1/HSF4/SP4 control of HSP90 gene expression.
Results :
Among the 4 heat shock proteins, HSP90 is the most abundant and HSP40 is the least abundant (about 15-fold less than that of HSP90) in both normal and cataractous lenses. Compared with HSP90, HSP70 and HSP60 are about 8-fold less in both normal and cataract patients. Compared with normal lenses, HSP90 and HSP40 are downregulated in cataractous lenses. In contrast, HSP70 and HSP60 are upregulated from transparent lenses to cataractous lenses. In different age groups of cataractous patients, the levels of HSP90, HSP70 and HSP40 remain relatively stable from 50s to 70s. HSP60 displays significant downregulation from 60s to 70s. From 70s to 80s, HSP70 dispays significant downregulation, and HSP60 resumes its level detected in 50s and 60s. In mouse lens epithelial cells, CRISPR/Cas9-mediated knockdown of HSP90 enhances oxidative stress-induced apoptosis.
Conclusions :
our results demonstrated that HSP90 is a dominant heat shock protein in the ocular lenses and plays an important role in preventing stress-induced apoptosis and cataractogenesis. (Supported by the grants, #81770910, #81970787, from the NSFC, the grant, 2019B1515120014 from the NSFG and the Fundamental Funds, 3030901010110 of the State Key Laboratory of Ophthalmology of Zhongshan Ophthalmic Center, and the Graduate Scholarship from Sun Yat-sen University).
This is a 2021 ARVO Annual Meeting abstract.