The Existence of mRNAs and miRNAs Expressions for Maintaining Cell Survival Networks Associated with the Human Transparent and Cataractous Lens

Background: Human lens cells have a long lifespan and so must maintain cell survival networks with regulate biological processes including gene expression and regulation. The purpose of this study was to identify mRNA transcript differences in the transparent and cataractous human lens. Methods: The expression of 25 genes was examined at RNA level in human lenses, including miRNA-205, miRNA-137, and mirlet-7A. All genes were isolated from 9 subjects with senile cataractous lenses and 5 subjects with transparent lenses as a control. The gene expressions were determined by methods of Real Time PCR (qRT-PCR). All genes were normalized to internal control by using Gapdh gene expression, and the calculations were based on the 2-ΔΔCt method. Results: Seven genes had lower levels of expression in the samples from cataractous lenses (p21, p27, Cox2, CygB, Mirlet-7A, Caspase-3 and CryAA) and 5 genes had higher levels of expression in cataractous lenses (Mir-205, SIRT3, HSP60, miR137 and Akt). The remaining 13 were not significantly different. The increasing of Sirt3, Hsp60, and Akt in cataractous lens suggested these genes protected and maintained lens cells survival and both miR-205 and miR-137 might also involve in lens cell survival networks. These two microRNA different profile from miR-7A that was down-regulated. Interestingly, increasing of Hsp60 indicated the inflammatory reaction or immune reaction might be involved in pathogenesis of cataract. p21 and p27 were down-regulated in cataractous lens, suggested the role of these genes in maintaining cell senescent decreased. Interestingly, the CygB was down-regulated in cataractous lens, this is also indicating hypoxic may be one of the risk factor in cataract. Conclusion: Collectively, our data showed that of 25 detected gene expressions in cataractous lens, 13 genes were different from transparent lens. Interestingly, the Hsp60 might be associated with inflammatory reaction or immune system and CygB might be associated with hypoxic state of lens cells, suggested both Hsp60 and CygB were important in pathogenesis of human cataract. In addition, miR-205 and miR-137 expressions that were increased strongly in cataractous lens and decreasing of mirlet-7A indicated that these three miRNAs involved in cell lens network regulation.