研究登革病毒誘發微小膠細胞運動性

Study on Dengue Virus-induced Cell Motility in Microglia

詹茗凱(Ming-Kai Jhan)

指導教授 ： 林秋烽

臺北醫學大學/醫學院/醫學科學研究所/碩士(2016年)

摘要

黃病毒家族中的登革病毒屬於正股單鏈RNA病毒，感染登革病毒時會引起輕微或嚴重的登革疾病。除了登革出血熱或登革休克症，部分登革患者會顯現出神經相關症狀像是急性病毒性腦炎。此外，動物研究及臨床檢體的檢驗均證實在登革病毒感染腦部區域可以觀察到微小膠細胞的活化；然而，目前對於登革病毒感染對於微小膠細胞的影響仍不清楚。實驗室先前的研究發現登革病毒可在體內及體外模式造成微小膠細胞的感染。本論文進一步探討登革病毒感染對微小膠細胞的影響。實驗結果證實四種血清型登革病毒均會造成小鼠微小膠細胞株的感染，包括病毒進入、病毒核糖核酸複製、病毒蛋白表現以及病毒顆粒釋放。登革病毒感染會引起微小膠細胞形成多極表現形態，同時感染並不會造成微小膠細胞生長抑制與細胞毒性。登革病毒感染過後細胞運動能力也會明顯增加。抑制肌動蛋白纖維抑或是網格蛋白，能夠阻礙登革病毒透過調控網格蛋白調節的內吞作用進入細胞所增加的微小膠細胞移行作用。我們進一步發現，利用紫外光抑制登革病毒活性並不會造成細胞移行作用，以及透過藥物方式阻斷類鐸受體3都能減少登革病毒增加的微小膠細胞移行作用。伴隨登革病毒感染類鐸受體3相關訊息傳遞銜接蛋白會活化並驅動細胞移行作用。然而，受登革病毒感染的微小膠細胞所分泌的化學趨化激素也同樣參與在細胞移行作用中。這些研究結果進一步證明登革病毒感染增加微小膠細胞移行作用是透過病毒進入、病毒核糖核酸釋放與類鐸受體3的機制所引起的。

關鍵字

登革病毒；微小膠細胞；移行；體外模式；類鐸體受體3；訊息傳遞

並列摘要

Infection of dengue virus (DENV), a positive single-stranded RNA virus in the family of Flavivirus, causes mild and severe dengue diseases. In addition to dengue hemorrhagic fever or dengue shock syndrome, dengue patients partly show neurological manifestations such as acute viral encephalitis. Moreover, animal studies and clinical specimens have demonstrated that activated microglial cells are present in DENV-infected brains; however, the possible effects of DENV on microglia remain unclear. Studies in our laboratory report that DENV infection causes microglial cell infection in vitro and in vivo. This study further investigated the effects of DENV on microglial cells. Here we demonstrated the infectious ability of four serotypes of DENV, including viral entry, RNA replication, viral protein expression, and virus release, in murine microglial cell line BV2. Without affecting cell growth and cytotoxicity, DENV infection caused an increase in the formation of multipolar phenotype. Cell motility was considerably increased following DENV infection. Disrupting either actin filaments or clathrin retarded DENV-increased cell migration while clathrin-regulated endocytosis mediated DENV entry. We further found that Ultraviolet-inactivated DENV did not affect cell migration and pharmacologically blocking toll-like receptor (TLR) 3 can reduced DENV-increased cell migration. Following DENV infection, TLR3-related Src, phosphoinositide 3-kinase, and NF-κB were activated for triggering cell migration. Furthermore, chemokine secretion from DENV-infected microglial cells might be involved in cell migration. These results demonstrate an advanced effect of DENV infection on microglia cell migration through a mechanism involving signaling of viral entry, RNA release, and TLR3 activation.

並列關鍵字

DENV ； Microglia ； Migration ； In vitro ； TLR3 ； Signaling

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