P58IPK inhibition of endoplasmic reticulum stress in human retinal capillary endothelial cells in vitro
P58IPK inhibition of endoplasmic reticulum stress in human retinal capillary endothelial cells in vitro
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DOI：
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发表时间：
2008-07
期刊：
影响因子：
2.2
通讯作者：
Bin Li;Dong Li;G. Li;Hao-wen Wang;A. Yu
中科院分区：
文献类型：
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作者：
Bin Li;Dong Li;G. Li;Hao-wen Wang;A. Yu
Purpose The goal of this research was to determine if P58IPK, a member of the Hsp40 family that inhibits eukaryotic initiation factor 2α (eIF2α), inhibits endoplasmic reticulum (ER) stress and leads to downregulated expression of vascular endothelial growth factor (VEGF) and decreased apoptosis in human retinal capillary endothelial cells (HRCECs). Methods Recombinant vectors were constructed using P58 in adeno-associated virus type 2 (rAAV2-P58 IPK) and P58 RNA in the plasmid pGIPZ (pGIPZ-P58IPK). The four experimental groups were: (1) non-transfected/non ER stressed control; (2) non-transfected/ER stressed; (3) rAAV2-P58IPK-transfected/ER stressed; and (4) pGIPZ- P58IPK RNAi transfected/ER stressed. ER stress was induced by treating cells with tunicamycin. Expression of P58IPK was determined in transfected cells. Expressions of the following factors were assessed: vascular endothelial growth factor (VEGF), C/EBP homologous protein (CHOP), activating transcription factor 4 (ATF4), and glucose-regulated protein 78 (GRP78). Apoptosis levels were also determined. Results Significantly increased expression of P58IPK was detected in cells transfected with rAAV2-P58IPK (0.63±0.02) as compared to those transfected with pGIPZ-P58IPK RNAi (0.23±0.01). P58IPK expression was not different between the control transfected cells (rAAV2-GFP and pGIPZ-GFP). Following ER stress, expression levels of ATF-4, GRP78, CHOP, and VEGF in cells overexpressing P58IPK were not different from those in unstressed control cells. This inhibitory effect of P58IPK on the expression of ER stress-related factors was suppressed in cells transfected with pGIPZ-P58IPK RNAi. Apoptosis was significantly increased in cells transfected with pGIPZ-P58IPK RNAi but not with rAAV2-P58IPK. Conclusions The study demonstrates that P58IPK inhibits ER stress and plays an important role in maintaining balance and stability of the ER in HRCECs.
