UVB irradiation-induced dysregulation of plasma membrane calcium ATPase1 and intracellular calcium homeostasis in human lens epithelial cells
Ultraviolet B (UVB) could lead to the apoptosis of human lens epithelial cell and be hypothesized to be one of the important factors of cataractogenesis. In the human lens, Ca2+-ATPase is a major determinant of calcium homeostasis. Plasma membrane calcium ATPase1 (PMCA1) is a putative “housekeeping” isoform and is widely expressed in all tissues and cells, which plays an important role in calcium homeostasis. However, the effects of UVB-irradiation on the expression of PMCA1 and the cellular calcium homeostasis are still unclear. In the present study, we cultured human lens epithelial cells (HLE B-3) in vitro and investigated the effects of UVB irradiation on the expression of PMCA1 and the intracellular calcium homeostasis using real-time cell electronic sensing system, flow cytometry, fluo-3/AM probes, real-time quantitative PCR, and enzyme-linked immunosorbent assay techniques. We found that UVB irradiation could induce human lens epithelial cell death, cause intracellular calcium ion (Ca2+) elevation, inhibit Ca2+-ATPase activity and decrease the expression of PMCA1 at gene and protein levels, suggesting that the downregulation of PMCA1 and the disruption of calcium homeostasis may play important roles in UVB-induced HLE B-3 cell apoptosis.
KeywordsUltraviolet B Calcium homeostasis Plasma membrane calcium ATPase1 Apoptosis Human lens epithelial cell
This work was supported by the Natural Science Foundation of Shandong province (ZR2010HM032).
Conflict of interest
The authors declare that they have no competing interests.
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