Balasubramanian Anuradha, Munshi Neru, Koziel Margaret J, Hu Zongyi, Liang T Jake, Groopman Jerome E, Ganju Ramesh K
Division of Experimental Medicine, Beth Israel Deaconess Medical Center, Harvard Medical School, 4 Blackfan Circle, 3rd Floor, Boston, MA 02115, USA.
Division of Infectious Diseases, Beth Israel Deaconess Medical Center, Harvard Medical School, 4 Blackfan Circle, 3rd Floor, Boston, MA 02115, USA.
J Gen Virol. 2005 Dec;86(Pt 12):3291-3301. doi: 10.1099/vir.0.81056-0.
Hepatitis C virus (HCV) infection is associated with inflammation of liver endothelium, which contributes to the pathogenesis of chronic hepatitis. The mechanism of this endothelitis is not understood, since the virus does not appear to infect endothelial cells productively. Here, an 'innocent bystander' mechanism related to HCV proteins was hypothesized and it was investigated whether the binding of HCV particles to human endothelium induced functional changes in the cells. Exposure of human umbilical vein endothelial cells (HUVECs) to HCV-like particles (HCV-LPs) resulted in increased interleukin 8 (IL8) production and induction of apoptosis. The IL8 supernatants collected after stimulation of HUVECs with HCV-LPs, BV-GUS (control baculovirus containing beta-glucuronidase) and appropriate controls were used to assay the transendothelial migration of neutrophils. This assay confirmed that HCV-LP-induced IL8 was functionally active. Using specific NF-kappaB inhibitors, it was also shown that HCV-LP-induced NF-kappaB activity mediated IL8 production in HUVECs. Apoptosis appeared to be mediated by the Fas/Fas-L pathway, as neutralizing antibodies for Fas and Fas-L significantly protected HUVECs against HCV-LP-induced apoptosis. Treatment of HUVECs with HCV-LPs also enhanced cellular Fas-L expression and augmented caspase-3 activation. This was confirmed by using a specific caspase-3 inhibitor, Z-Asp-Glu-Val-Asp-fluoromethyl ketone. As shown by blocking of specific chemokine receptors for IL8 on HUVECs, the induction of IL8 did not appear to contribute to HCV-LP-induced apoptosis. These results suggest that HCV proteins can trigger the release of inflammatory chemokines such as IL8 and cause endothelial apoptosis, thereby facilitating endothelitis.
丙型肝炎病毒（HCV）感染与肝内皮炎症相关，这有助于慢性肝炎的发病机制。这种内皮炎的机制尚不清楚，因为该病毒似乎不会有效感染内皮细胞。在此，提出了一种与HCV蛋白相关的“无辜旁观者”机制，并研究了HCV颗粒与人内皮细胞的结合是否会诱导细胞功能变化。将人脐静脉内皮细胞（HUVECs）暴露于HCV样颗粒（HCV-LPs）会导致白细胞介素8（IL8）产生增加和细胞凋亡诱导。用HCV-LPs、BV-GUS（含β-葡萄糖醛酸酶的对照杆状病毒）和适当对照刺激HUVECs后收集的IL8上清液用于检测中性粒细胞的跨内皮迁移。该检测证实了HCV-LP诱导的IL8具有功能活性。使用特异性NF-κB抑制剂还表明，HCV-LP诱导的NF-κB活性介导了HUVECs中IL8的产生。凋亡似乎是由Fas/Fas-L途径介导的，因为针对Fas和Fas-L的中和抗体显著保护HUVECs免受HCV-LP诱导的凋亡。用HCV-LPs处理HUVECs也增强了细胞Fas-L表达并增强了caspase-3激活。使用特异性caspase-3抑制剂Z-Asp-Glu-Val-Asp-氟甲基酮证实了这一点。如通过阻断HUVECs上IL8的特异性趋化因子受体所示，IL8的诱导似乎与HCV-LP诱导的凋亡无关。这些结果表明，HCV蛋白可触发IL8等炎性趋化因子的释放并导致内皮细胞凋亡，从而促进内皮炎。
