Huang M B, Bond V C
Department of Biochemistry, Morehouse School of Medicine, Atlanta, Georgia 30310-1495, USA.
J Acquir Immune Defic Syndr. 2000 Dec 15;25(5):375-89. doi: 10.1097/00042560-200012150-00001.
We previously showed that HIV-1 gp120-induced apoptosis in primary human umbilical vein endothelial cell cultures (HUVEC), through CCR5 and CXCR4. Here, we have found that agonists of protein kinase C (PKC), basic fibroblast growth factor (bFGF), and short exposure to low concentrations of phorbol esters were found to block gp120-induced apoptosis in HUVEC cultures. PKC antagonists, sphingosine, H7, and extended exposure of cultures to high concentrations of phorbol esters were also found to block gp120-induced apoptosis in HUVEC cultures. A significant increase in the total amount of cellular PKC enzymatic activity was observed on exposure of HUVEC to gp120. No increase in total PKC activity was observed on exposure of HUVECs to the natural ligands SDF-1alpha, or regulated-on-activation normal T-expressed and secreted (RANTES) cells, and gp120-induced PKC induction was found to be totally blocked by CXCR4 antibodies and partially blocked by the caspase 3 inhibitor, DEVD-CHO. Alternatively, CXCR4 antibodies and DEVD-CHO totally blocked apoptosis. Finally, gp120-induced effects were found to be insensitive to pertussis toxin. Accumulated evidence suggests PKC involvement at multiple points in the gp120-induced apoptotic pathway; also suggests involvement of the CXCR4 receptor internalization pathway, and potentially suggests different downstream effects of gp120-receptor interactions and natural ligand-receptor interactions.
我们之前表明，HIV-1 gp120通过CCR5和CXCR4在原代人脐静脉内皮细胞培养物（HUVEC）中诱导细胞凋亡。在此，我们发现蛋白激酶C（PKC）激动剂、碱性成纤维细胞生长因子（bFGF）以及短时间暴露于低浓度佛波酯可阻断HUVEC培养物中gp120诱导的细胞凋亡。PKC拮抗剂、鞘氨醇、H7以及将培养物长时间暴露于高浓度佛波酯也可阻断HUVEC培养物中gp120诱导的细胞凋亡。在HUVEC暴露于gp120时，观察到细胞PKC酶活性总量显著增加。在HUVEC暴露于天然配体SDF-1α或正常T细胞激活后表达和分泌的调节趋化因子（RANTES）时，未观察到总PKC活性增加，并且发现gp120诱导的PKC诱导被CXCR4抗体完全阻断，被半胱天冬酶3抑制剂DEVD-CHO部分阻断。另外，CXCR4抗体和DEVD-CHO完全阻断细胞凋亡。最后，发现gp120诱导的效应对百日咳毒素不敏感。积累的证据表明PKC在gp120诱导的凋亡途径中的多个点发挥作用；还表明CXCR4受体内化途径的参与，并且潜在地表明gp120-受体相互作用和天然配体-受体相互作用的不同下游效应。
