嗜铬粒蛋白A衍生多肽CHR抑制LPS诱导的永生化脑微血管内皮细胞高通透性

Chromogranin A derived peptide CGA47-66 suppresses hyperpermeability of immortalized brain microvascular endothelial cells induced by lipopolysaccharide

目的探讨嗜铬粒蛋白A衍生多肽CHR(chromofungin)对LPS所诱导的永生化人脑微血管内皮细胞高通透性的影响。方法分别用LPS、CHR、CGA4-16作用于人脑微血管内皮细胞(human brain microvascular endothelial cells,HBMEC),用CCK8法检测不同浓度LPS刺激HBMEC细胞活力变化;EVOM法及Transwell小室法检测内皮细胞相对通透性;Western blot及RT-PCR法检测紧密连接蛋白(ZO-1和Claudin-5)的表达情况。结果与空白组相比,随着LPS浓度增加,HBMEC细胞的活性受到显著抑制(P<0.05)。随着LPS作用时间延长,其细胞内紧密连接蛋白ZO-1、Claudin-5的表达逐渐下调,6 h后蛋白表达量降到最低(P<0.05),12 h和24 h后其蛋白表达与6 h相比无明显差异。LPS作用下HBMEC单层细胞电阻值明显降低(t=-18.214,P<0.001),细胞通透性显著升高(t=6.083,P=0.004),ZO-1、Claudin-5的蛋白和mRNA表达明显下调(P<0.05),而CHR可显著改善上述变化。结论嗜铬粒蛋白A衍生多肽CHR能通过上调紧密连接相关蛋白的表达从而改善LPS所致的脑微血管内皮细胞高通透性。

Objective To determine the effect of chromogranin A derived peptide CGA47-66 （chromofungin, CHR ） on lipopolysaceharide （LPS） induced high permeability of immortalized brain microvascular endothelial cells. Methods Immortalized human brain microvaseular endothelial cells （HBMEC） were exposed to LPS, CHR and CGA4-16 respectively. Cell counting kit-8 （CCK8） assay was used to detect the cell viability after inducement of different concentrations of LPS. The relative permeability of HBMEC cells was measured by a Transwell chamber system and epithelial voltmeter （EVOM）. The expression levels of the tight junction protein ZO-1 and Claudin-5 were detected by Western blotting and quantitative real- time polymerase chain reaction （RT-PCR）. Results Compared with the blank control cells, the viability of HBMEC cells was significantly inhibited with the increase concentrations of LPS （ P 〈 0.05 ）. With the elapse of time, LPS treatment decreased the expression levels of ZO-1 and Claudin-5 gradually, and the levels reached the lowest after 6 h （P 〈 0.05 ） , which having no significant difference with the levels at 12 or 24 h. LPS treatment also resulted in significantly decreased transendothelial electrical resistance （t = -18. 214, P 〈 0.001 ） , increased cell permeability （t = 6. 083, P = 0. 004） , and down-regulation of ZO-1 and Claudin-5 at mRNA and protein levels （P 〈 0. 05 ）. However, CHR significantly attenuated the above changes. Conclusion CHR could attenuate the hyperperneability of human brain microvascular endothelial cells induced by LPS through up-regulating tight junction proteins.