Dengue virus induces murine microvascular endothelial cell apoptosis

• Main Authors: Yu-Hwa Huang, 黃郁華
• Other Authors: Betty Wu-Hsieh
• Format: Others
• Language: en_US
• Published: 2004
• Online Access: http://ndltd.ncl.edu.tw/handle/32140103813482296047

碩士 === 國立臺灣大學 === 免疫學研究所 === 92 === Endothelial cell death is suggested as a mechanism by which dengue virus causes hemorrhage, the hallmark of dengue hemorrhagic fever and dengue shock syndrome (DHF/DSS). It has never been examined whether dengue virus causes endothelial cell death. The present study was designed to address this question in mouse as well as human endothelial cells. Mouse primary microvascular endothelial cells were isolated from collagenase-treated mouse brain tissue. The isolated cells expressed CD31 and endothelial nitric oxide synthase (eNOS). The results showed that dengue virus serotype 2 strain 16681 established a productive infection in primary mouse microvascular endothelial cells, induced inducible nitric oxide synthase (iNOS) and apoptotic cell death. Use of NOS inhibitor, n-nitroso-L-arginine methyl ester (L-NAME) reduced dengue virus-induced apoptosis. Dengue virus-induced apoptosis was also reduced in endothelial cells isolated from iNOS-/- mice. These observations indicated that high output NO was involved in denguevirus-induced endothelial cell apoptosis. HUVEC, primary human macrovascular endothelial cells, and HMEC, transformed human microvascular cell line infected with dengue virus like that in primary mouse endothelial cells also underwent apoptosis. Virus-induced apoptotic cell death was partially reduced by treatment with either L-NAME or reactive oxygen species (ROS) scavenger N-acetyl cysteine alone and completed inhibited by treatment with both inhibitors. These results indicated that both NO and ROS were involved in causing dengue virus-induced endothelial cell damage. Moreover, zVAD-fmk (pan-caspase inhibitor) prevented dengue-virus induced-apoptosis, demonstrating that dengue virus-induced endothelial cell death was caspase-dependent. Taken together, results in this study showed that dengue virus infects mouse as well as human endothelial cells. The infection induces high output of NO. Through the combined effect of NO and ROS, dengue virus induces endothelial cell death. These results point out a potentia relationship between dengue virus-induced endothelial cell death and dengue pathogenesis. In addition, interaction between dengue virus and mouse endothelial cells modeled that between the virus and human cells, suggesting a possibility of using mouse model to study dengue pathogenesis.