Emerging coronaviruses (CoVs) primarily cause severe gastroenteric or respiratory diseases in humans and animals, and no approved therapeutics are currently available. Here, A9, a receptor tyrosine kinase inhibitor (RTKI) of the tyrphostin class, is identified as a robust inhibitor of transmissible gastroenteritis virus (TGEV) infection in cell-based assays. Moreover, A9 exhibited potent antiviral activity against the replication of various CoVs, including murine hepatitis virus (MHV), porcine epidemic diarrhea virus (PEDV) and feline infectious peritonitis virus (FIPV). We further performed a comparative phosphoproteomic analysis to investigate the mechanism of action of A9 against TGEV infection in vitro. We specifically identified p38 and JNK1, which are the downstream molecules of receptor tyrosine kinases (RTKs) required for efficient TGEV replication, as A9 targets through plaque assays, qRT-PCR and Western blotting assays. p38 and JNK1 inhibitors and RNA interference further showed that the inhibitory activity of A9 against TGEV infection was mainly mediated by the p38 mitogen-activated protein kinase (MAPK) signaling pathway. All these findings indicated that the RTKI A9 directly inhibits TGEV replication and that its inhibitory activity against TGEV replication mainly occurs by targeting p38, which provides vital clues to the design of novel drugs against CoVs.

中文翻译：

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受体酪氨酸激酶抑制剂主要通过p38丝裂原激活的蛋白激酶途径阻断TGEV的增殖。

新兴的冠状病毒（CoV）主要引起人和动物的严重胃肠道疾病或呼吸道疾病，目前尚无批准的治疗方法。在此，在基于细胞的检测中，A9是酪氨酸受体蛋白类的受体酪氨酸激酶抑制剂（RTKI），被确定为可传播性肠胃炎病毒（TGEV）感染的强效抑制剂。此外，A9对多种CoV的复制表现出强大的抗病毒活性，包括鼠肝炎病毒（MHV），猪流行性腹泻病毒（PEDV）和猫传染性腹膜炎病毒（FIPV）。我们进一步进行了比较磷酸化蛋白质组学分析，以研究A9体外抗TGEV感染的作用机理。我们专门鉴定了p38和JNK1，它们是有效TGEV复制所需的受体酪氨酸激酶（RTK）的下游分子，因为A9可通过噬斑测定，qRT-PCR和Western印迹测定来靶向。p38和JNK1抑制剂以及RNA干扰进一步表明，A9对TGEV感染的抑制活性主要是由p38丝裂原激活的蛋白激酶（MAPK）信号传导途径介导的。所有这些发现表明，RTKI A9直接抑制TGEV复制，并且其对TGEV复制的抑制活性主要是通过靶向p38来实现的，这为设计针对CoV的新型药物提供了重要的线索。p38和JNK1抑制剂以及RNA干扰进一步表明，A9对TGEV感染的抑制活性主要是由p38丝裂原激活的蛋白激酶（MAPK）信号传导途径介导的。所有这些发现表明，RTKI A9直接抑制TGEV复制，并且其对TGEV复制的抑制活性主要是通过靶向p38来实现的，这为设计针对CoV的新型药物提供了重要的线索。p38和JNK1抑制剂以及RNA干扰进一步表明，A9对TGEV感染的抑制活性主要是由p38丝裂原激活的蛋白激酶（MAPK）信号传导途径介导的。所有这些发现表明，RTKI A9直接抑制TGEV复制，并且其对TGEV复制的抑制活性主要是通过靶向p38来实现的，这为设计针对CoV的新型药物提供了重要的线索。