Evidence that TMPRSS2 Activates the Severe Acute Respiratory Syndrome Coronavirus Spike Protein for Membrane Fusion and Reduces Viral Control by the Humoral Immune Response
Evidence that TMPRSS2 Activates the Severe Acute Respiratory Syndrome Coronavirus Spike Protein for Membrane Fusion and Reduces Viral Control by the Humoral Immune Response
复制标题
DOI：
10.1128/jvi.02232-10
复制
发表时间：
2011-05-01
影响因子：
5.4
通讯作者：
Poehlmann, Stefan
中科院分区：
文献类型：
--
作者：
Glowacka, Ilona;Bertram, Stephanie;Poehlmann, Stefan
严重急性呼吸综合征冠状病毒（SARS-CoV）的刺突蛋白（S）在病毒摄取到靶细胞内体后可被组织蛋白酶B和L蛋白水解激活。相反，位于感染细胞分泌途径和/或靶细胞表面的宿主细胞蛋白酶是否能切割SARS S在很大程度上是未知的。我们与其他人沿着先前可以显示II型跨膜蛋白酶TMPRSS 2通过切割激活流感病毒血凝素和人偏肺病毒F蛋白。在这里，我们评估了SARS S是否被TMPRSS 2蛋白水解处理。Western印迹分析显示，SARS S在共表达TMPRSS 2（顺式切割）和SARS S表达细胞与TMPRSS 2阳性细胞接触（反式切割）时被切割成几个片段。顺式切割导致SARS S片段释放到细胞上清液中并抑制抗体介导的中和，这很可能是因为SARS S片段起抗体诱饵的作用。反式切割激活效应细胞上的SARS S，用于与靶细胞融合，并允许SARS S驱动的病毒有效进入用亲溶酶体剂或组织蛋白酶抑制剂处理的靶细胞。最后，ACE 2，SARS-CoV的细胞受体，和TMPRSS 2被发现共表达的II型肺细胞，这是重要的病毒靶细胞，表明SARS S被切割的TMPRSS 2在SARS-冠状病毒感染的个人的肺。总之，我们发现TMPRSS 2可能通过中和抗体减少病毒识别和激活SARS S进行细胞-细胞和病毒-细胞融合来促进病毒传播和致病。
The spike (S) protein of the severe acute respiratory syndrome coronavirus (SARS-CoV) can be proteolytically activated by cathepsins B and L upon viral uptake into target cell endosomes. In contrast, it is largely unknown whether host cell proteases located in the secretory pathway of infected cells and/or on the surface of target cells can cleave SARS S. We along with others could previously show that the type II transmembrane protease TMPRSS2 activates the influenza virus hemagglutinin and the human metapneumovirus F protein by cleavage. Here, we assessed whether SARS S is proteolytically processed by TMPRSS2. Western blot analysis revealed that SARS S was cleaved into several fragments upon coexpression of TMPRSS2 (cis-cleavage) and upon contact between SARS S-expressing cells and TMPRSS2-positive cells (trans-cleavage). cis-cleavage resulted in release of SARS S fragments into the cellular supernatant and in inhibition of antibody-mediated neutralization, most likely because SARS S fragments function as antibody decoys. trans-cleavage activated SARS S on effector cells for fusion with target cells and allowed efficient SARS S-driven viral entry into targets treated with a lysosomotropic agent or a cathepsin inhibitor. Finally, ACE2, the cellular receptor for SARS-CoV, and TMPRSS2 were found to be coexpressed by type II pneumocytes, which represent important viral target cells, suggesting that SARS S is cleaved by TMPRSS2 in the lung of SARS-CoV-infected individuals. In summary, we show that TMPRSS2 might promote viral spread and pathogenesis by diminishing viral recognition by neutralizing antibodies and by activating SARS S for cell-cell and virus-cell fusion.