College of Veterinary Medicine, Northeast Agricultural University, Harbin 150030, China.
Harbin Veterinary Research Institute, Chinese Academy of Agricultural Sciences, Harbin 150001, China.
Viruses. 2017 May 18;9(5):114. doi: 10.3390/v9050114.
Type II transmembrane serine proteases (TTSPs) facilitate the spread and replication of viruses such as influenza and human coronaviruses, although it remains unclear whether TTSPs play a role in the progression of animal coronavirus infections, such as that by porcine epidemic diarrhea virus (PEDV). In this study, TTSPs including TMPRSS2, HAT, DESC1, and MSPL were tested for their ability to facilitate PEDV replication in Vero cells. Our results showed that TMPRSS2 and MSPL played significant roles in the stages of cell-cell fusion and virus-cell fusion, whereas HAT and DESC1 exhibited weaker effects. This activation may be involved in the interaction between TTSPs and the PEDV S protein, as the S protein extensively co-localized with TMPRSS2 and MSPL and could be cleaved by co-expression with TMPRSS2 or MSPL. Moreover, the use of Vero cells expressing TMPRSS2 and MSPL facilitated PEDV replication in the absence of exogenous trypsin. In sum, we identified two host proteases, TMPRSS2 and MSPL, which may provide insights and a novel method for enhancing viral titers, expanding virus production, and improving the adaptability of PEDV isolates in vitro.
II 型跨膜丝氨酸蛋白酶（TTSPs）促进病毒（如流感病毒和人类冠状病毒）的传播和复制，尽管 TTSPs 是否在动物冠状病毒感染（如猪流行性腹泻病毒（PEDV））的进展中发挥作用仍不清楚。在这项研究中，检测了 TMPRSS2、HAT、DESC1 和 MSPL 等 TTSPs 促进 Vero 细胞中 PEDV 复制的能力。我们的结果表明，TMPRSS2 和 MSPL 在细胞-细胞融合和病毒-细胞融合阶段发挥重要作用，而 HAT 和 DESC1 则表现出较弱的作用。这种激活可能涉及 TTSPs 与 PEDV S 蛋白之间的相互作用，因为 S 蛋白与 TMPRSS2 和 MSPL 广泛共定位，并且可以通过与 TMPRSS2 或 MSPL 共表达而被切割。此外，使用表达 TMPRSS2 和 MSPL 的 Vero 细胞在没有外源性胰酶的情况下促进了 PEDV 的复制。总之，我们鉴定了两种宿主蛋白酶，TMPRSS2 和 MSPL，它们可能为提高病毒滴度、扩大病毒产量以及提高 PEDV 分离株在体外的适应性提供了新的见解和方法。
