Carbajal J M, Schaeffer R C
Department of Veteran Affairs Medical Center, University of Arizona, Tucson, Arizona, 85723, USA.
Biochem Biophys Res Commun. 1998 Aug 19;249(2):461-6. doi: 10.1006/bbrc.1998.9172.
The effects of hydrogen peroxide (H2O2) and the protein tyrosine kinase (PTK) inhibitor, genistein, to modulate protein tyrosine phosphorylation (PTP) and endothelial barrier function were examined in bovine pulmonary artery endothelial cell (EC) monolayers. H2O2 stimulated a concentration (100-800 microM) and time-dependent increase in the phosphotyrosine (PY) content of multiple (56-72, 93-97, 113-142, and 161-183 kDa) EC proteins. A size-selected solute permeability assay of EC monolayer barrier function showed that (200 microM) H2O2 elevated EC monolayer permeability to large solutes. This effect was associated with paracellular hole formation and a loss of beta-catenin immunostaining at these sites. In contrast, genistein (100 microM, 1 h) reduced basal PY protein content and reorganized F-actin to beta-catenin containing cell-cell junctions, enhancing endothelial monolayer barrier function. In addition, genistein prevented the H2O2-induced increases in tyrosine phosphorylation, monolayer permeability, and paracellular hole formation. These data suggest that H2O2 and genistein differentially regulate PTP, endothelial morphology, and monolayer barrier function.
在牛肺动脉内皮细胞（EC）单层中，研究了过氧化氢（H2O2）和蛋白酪氨酸激酶（PTK）抑制剂染料木黄酮对调节蛋白酪氨酸磷酸化（PTP）和内皮屏障功能的影响。H2O2刺激多种（56 - 72、93 - 97、113 - 142和161 - 183 kDa）EC蛋白的磷酸酪氨酸（PY）含量呈浓度（100 - 800 microM）和时间依赖性增加。EC单层屏障功能的大小选择溶质通透性测定表明，（200 microM）H2O2提高了EC单层对大溶质的通透性。这种效应与细胞旁孔形成以及这些部位β-连环蛋白免疫染色的丧失有关。相反，染料木黄酮（100 microM，1小时）降低了基础PY蛋白含量，并将F-肌动蛋白重组为含β-连环蛋白的细胞间连接，增强了内皮单层屏障功能。此外，染料木黄酮可防止H2O水2诱导的酪氨酸磷酸化增加、单层通透性增加和细胞旁孔形成。这些数据表明，H2O2和染料木黄酮对PTP、内皮形态和单层屏障功能有不同的调节作用。
