Effect of multidrug resistant associated protein 4 overexpression on lipopolysaccharide-induced vascular endothelial hyperpermeability and its mechanism
10.3760/cma.j.issn.2095-4352.2017.07.007
- VernacularTitle:多药耐药相关蛋白4过表达对脂多糖诱导血管内皮高渗透性的影响及其机制
- Author:
Wenfang XIA
;
Huanming ZHANG
;
Yanlei ZHENG
;
Qingshan ZHOU
;
Bin SU
- Keywords:
Lipopolysaccharide;
Multidrug resistance protein 4;
Endothelial permeability;
Cyclic adenosine monophosphate
- From:
Chinese Critical Care Medicine
2017;29(7):608-612
- CountryChina
- Language:Chinese
-
Abstract:
Objective To investigate the effect of multidrug resistance protein 4 (MRP4) overexpression on lipopolysaccharide (LPS)-induced vascular endothelial hyperpermeability of rat pulmonary micro-vascular endothelial cells (PMVECs) and its molecule mechanism. Methods Three to six passages of PMVECs were cultured in vitro, and they were divided into three groups: the cells in LPS group were only challenged by LPS 10 μg/mL after being cultured in serum-free medium for 24 hours; the cells in Ad-shRNA and Ad-MRP4 groups were infected with the empty virus control or recombinant adenovirus expressing MRP4 for 2 hours, and then were cultured in serum-free medium for 24 hours followed by stimulation of LPS 10 μg/mL. Endothelial permeability was assayed by the Transwell chamber models at 2, 6, 12, and 24 hours after LPS stimulation. Intracellular cyclic adenosine monophosphate (cAMP) levels were detected by enzyme-linked immunosorbent assay (ELISA). The morphological characteristics and distribution of F-actin was determined by laser confocal fluorescence microscope. The protein expressions of MRP4,β-catenin, vascular endothelium-cadherin (VE-cad) and ZO-1 were measured by Western Blot. Results ① After LPS stimulation, endothelium permeability and intracellular cAMP levels in PMVECs were significantly increased, peaked at 12 hours, and then decreased after 24 hours. Compared with LPS group and Ad-shRNA group, PMVECs of Ad-MRP4 group were exhibited a significant increase in endothelial permeability [12-hour permeability (A value):1.88±0.06 vs. 1.12±0.17, 1.10±0.18] and a significant decrease in intracellular cAMP level [12-hour cAMP (μg/L):2.39±0.02 vs. 2.97±0.01, 3.00±0.02, all P < 0.05]. There was no significant difference in endothelium permeability and intracellular cAMP levels at all time points between the LPS group and the Ad-shRNA group (all P > 0.05).② Under laser confocal fluorescence microscope, after LPS stimulation, the stress fiber formation was induced in three groups. But there were pronounced irregular aggregation of fiber in PMVECs of Ad-MRP4 group. ③ Furthermore, compared with LPS group and Ad-shRNA group, protein expression of MRP4 in Ad-MRP4 group was dramatically increased (gray value: 0.76±0.03 vs. 0.44±0.02, 0.43±0.02, both P < 0.05), and the protein expressions of β-catenin, VE-cad, and ZO-1 were significantly decreased [β-catenin (gray value): 0.14±0.03 vs. 0.23±0.04, 0.23±0.03);VE-cad (gray value): 0.21±0.01 vs. 0.34±0.02, 0.35±0.04; ZO-1 (gray value): 0.14±0.02 vs. 0.37±0.06, 0.33±0.07, all P < 0.05]. There was no significant difference in all protein expressions between the LPS group and Ad-shRNA group (all P > 0.05). Conclusion MRP4 overexpression can decrease intracellular cAMP levels, reduce intercellular junction protein expression, and then exaggerate LPS-induced vascular endothelial hyperpermeability.
