Increased Association of Deamidated ?A-_N101D with Lens membrane of transgenic ?A_N101D vs. wild type ?A mice: potential effects on intracellular ionic imbalance and membrane disorganization.

ABSTRACT: We have generated two mouse models, in one by inserting the human lens ?AN101D transgene in CRY?A_N101D mice, and in the other by inserting human wild-type ?A-transgene in CRY?A_WT mice. The CRY?A_N101D mice developed cortical cataract at about 7-months of age relative to CRY?A_WT mice. The objective of the study was to determine the following relative changes in the lenses of CRY?A_N101D- vs. CRY?A_WT mice: age-related changes with specific emphasis on protein insolubilization, relative membrane-association of ?A_N101D vs. WT?A proteins, and changes in intracellular ionic imbalance and membrane organization.Methods: Lenses of varying ages from CRY?A_WT and CRY?A_N101D mice were compared for an age-related protein insolubilization. The relative lens membrane-association of the ?AN101D- and WT?A proteins in the two types of mice was determined by immunohistochemical-, immunogold-labeling-, and western blot analyses. The relative levels of membrane-binding of recombinant ?A_N101D- and WT?A proteins was determined by an in vitro assay, and the levels of intracellular Ca²⁺ uptake and Na, K-ATPase mRNA were determined in the cultured epithelial cells from lenses of the two types of mice.

Results: Compared to the lenses of CRY?A_WT, the lenses of CRY?A_N101D mice exhibited: (A) An increase in age-related protein insolubilization beginning at about 4-months of age. (B) A greater lens membrane-association of ?AN101D- relative to WT?A protein during immunogold-labeling- and western blot analyses, including relatively a greater membrane swelling in the CRY?A_N101D lenses. (C) During in vitro assay, the greater levels of binding ?AN101D- relative to WT?A protein to membranes was observed. (D) The 75% lower level of Na, K-ATPase mRNA but 1.5X greater Ca²⁺ uptake were observed in cultured lens epithelial cells of CRY?A_N101D- than those of CRY?A_WT mice.

Conclusions: The results show that an increased lens membrane association of ?A_N101D-_-relative WT?A protein in CRY?A_N101D mice than CRY?A_WT mice occurs, which causes intracellular ionic imbalance, and in turn, membrane swelling that potentially leads to cortical opacity.

SUBMITTER: Srivastava O 

PROVIDER: S-EPMC7726915 | biostudies-literature | 2020 Dec

REPOSITORIES: biostudies-literature