摘要
目的 探讨肿瘤坏死因子α(TNF α)对肺微血管内皮细胞 (PMVEC) β 受体 ( β AR)和 β AR相关的G蛋白偶联受体激酶 (GRKs)的影响及山莨菪碱的干预作用。方法 采用放射性配基结合法观察TNF α作用后大鼠PMVECβ AR最大结合容量Bmax的变化 ;采用Westernblot观察与 β AR相关的GRKs在蛋白水平的表达及TNF α的影响。 结果 大鼠PMVECβ AR的最大结合容量Bmax为 ( 5 5 8± 0 3 1)fmol/10 5细胞 ;TNF α组 β AR的Bmax显著低于对照组 ,TNF α +山莨菪碱组 β AR的Bmax与对照组比较无显著差异 ;大鼠PMVECGRK2蛋白表达为阳性 ,但GRK3、GRK5和GRK6表达为阴性 ;TNF α组和TNF α +山莨菪碱组GRK2蛋白表达较正常对照组显著增高。结论 大鼠PMVEC表达GRK2 ,但不表达GRK3、GRK5和GRK6;TNF α诱导的GRK2表达增高可促进 β AR的磷酸化 ,从而促进 β AR与G蛋白失偶联和 β AR的内化 ,这可能是TNF α致大鼠PMVECβ AR下调的主要机制 ;山莨菪碱不是通过抑制GRK2表达增加 ,而是通过其它机制抑制TNF α引起的 β
Objective To investigate the effects of tumor necrosis factor α (TNF α) on β adrenoceptor (β AR) and β AR related G protein coupled receptor kinases (GRKs) in rat pulmonary microvascular endothelial cells (PMVECs) as well as the interfering action of anisodamine. Methods Radio ligand binding assay was used to measure the maximal binding capacity (B max ) changes of β AR in rat PMVECs after treatment with TNF α. The effects of TNF α and β AR related GRKs expression at the protein level were observed by Western blotting. Results B max of β AR in normal rat PMVECs was (5.58±0.31) fmol/10 5 cells. B max of β AR in TNF α group decreased significantly as compared with that in the normal control group, but no significant difference was found between the normal control group and TNF α+anisodamine group. The expression of GRK2 in rat PMVECs was positive, but expression of GRK3, GRK5, and GRK6 were negative. The expression of GRK2 in TNF α group and TNF α+anisodamine group increased significantly as compared with that in the normal control group, but no significant difference was found between the TNF α group and the TNF α+anisodamine group. Conclusion GRK2 but not GRK3, GRK5, or GRK6 is expressed in rat PMVECs. The increased expression of GRK2 induced by TNF α in rat PMVECs might promote the phosphorylation of β AR, leading to β AR internalization and decoupling with G protein, which might be the main mechanism of down regulation of β AR induced by TNF α. Anisodamine might inhibit the down regulation of β AR through other mechanism instead of inhibiting the increase of GRK2 expression.
出处
《第三军医大学学报》
CAS
CSCD
北大核心
2004年第10期859-862,共4页
Journal of Third Military Medical University
基金
国家自然科学基金资助项目 ( 30 0 70 334
39730 2 10 )
全军医学科研"十五"计划重点课题 ( 0 1Z0 74 )~~
关键词
肿瘤坏死因子Α
Β受体
G蛋白偶联受体激酶
微血管内皮细胞
大鼠
tumor necrosis factor alpha
beta adrenoceptor
G protein coupled receptor kinase
microvascular endothelial cell
rat
