冠状病毒(CoV)是重要的动物和人类病原体,其特征在于具有正义单链RNA的包膜RNA病毒。冠状病毒科包括四个属,其中大黄病毒对家禽业构成重大威胁,传染性支气管炎病毒(IBV)是这些威胁中最突出的。特别是,IBV对肉鸡生长和产蛋产生不利影响,造成重大损失。目前在台湾流行的IBV毒株包括IBV台湾-I(TW-I)血清型,IBV台湾-II(TW-II)血清型,和疫苗菌株。因此,正在进行的努力集中在开发新的疫苗和发现抗病毒药物。在病毒出芽之前,CoV的包膜(E)蛋白在内质网-高尔基体中间区室中积累。这些E蛋白组装成病毒孢子蛋白,表现出导致细胞膜破坏的离子通道活性,使它们成为抗病毒治疗的有吸引力的目标。在这项研究中,我们研究了IBVH-120的E蛋白,以及IBV血清型TW-I和TW-II。E蛋白表达导致细菌生长受到抑制,细菌对β-半乳糖苷酶底物的渗透性增加,并通过潮霉素B(HygB)阻断细菌的蛋白质合成。此外,在存在E蛋白的情况下,HygB还阻碍DF-1细胞中的蛋白质翻译并破坏其膜完整性。总的来说,这些发现证实了来自IBVH-120,IBV血清型TW-I,和IBV血清型TW-II。接下来,维波素抑制剂,5-(N,N-六亚甲基)阿米洛利(HMA)和4,4'-二硫氰酸-2,2'-二苯乙烯二磺酸(DIDS)用于抑制IBVH-120,IBV血清型TW-I,和IBV血清型TW-II。在鸡胚和感染IBV血清型TW-I和IBVTW-II的鸡中,在感染后6天和11天(dpi)没有观察到幸存者,分别。然而,DIDS和HMA均可提高受感染的鸡胚和鸡的存活率,并减轻气管和肾脏的组织病理学损伤。此外,通过同源性建模构建IBVE蛋白的3D五聚体结构。不出所料,发现两种抑制剂都与E蛋白跨膜域内的面向脂质的表面结合,抑制离子传导。一起来看,我们的研究结果提供了全面的证据,支持使用病毒传播素抑制剂作为针对IBV台湾分离株的有前景的抗病毒药物.
Coronaviruses (CoVs) are significant animal and human pathogens, characterized by being enveloped RNA viruses with positive-sense single-stranded RNA. The Coronaviridae family encompasses four genera, among which gammacoronaviruses pose a major threat to the poultry industry, which infectious bronchitis virus (IBV) being the most prominent of these threats. Particularly, IBV adversely affects broiler growth and egg production, causing substantial losses. The IBV strains currently circulating in Taiwan include the IBV Taiwan-I (TW-I) serotype, IBV Taiwan-II (TW-II) serotype, and vaccine strains. Therefore, ongoing efforts have focused on developing novel vaccines and discovering antiviral agents. The envelope (E) proteins of CoVs accumulate in the endoplasmic reticulum-Golgi intermediate compartment prior to virus budding. These E proteins assemble into viroporins, exhibiting ion channel activity that leads to cell membrane disruption, making them attractive targets for antiviral therapy. In this study, we investigated the E proteins of IBV H-120, as well as IBV serotypes TW-I and TW-II. E protein expression resulted in inhibited bacteria growth, increased permeability of bacteria to β-galactosidase substrates, and blocked protein synthesis of bacteria by hygromycin B (HygB). Furthermore, in the presence of E proteins, HygB also impeded protein translation in DF-1 cells and damaged their membrane integrity. Collectively, these findings confirm the
viroporin activity of the E proteins from IBV H-120, IBV serotype TW-I, and IBV serotype TW-II. Next, the
viroporin inhibitors, 5-(N,N-hexamethylene) amiloride (HMA) and 4,4\'-diisothiocyano stilbene-2,2\'-disulphonic acid (DIDS) were used to inhibit the
viroporin activities of the E proteins of IBV H-120, IBV serotype TW-I, and IBV serotype TW-II. In chicken embryos and chickens infected with IBV serotypes TW-I and IBV TW-II, no survivors were observed at 6 and 11 days post-infection (dpi), respectively. However, treatments with both DIDS and HMA increased the survival rates in infected chicken embryos and chickens and mitigated histopathological lesions in the trachea and kidney. Additionally, a 3D pentameric structure of the IBV E protein was constructed via homology modeling. As expected, both inhibitors were found to bind to the lipid-facing surface within the transmembrane domain of the E protein, inhibiting ion conduction. Taken together, our findings provide comprehensive evidence supporting the use of
viroporin inhibitors as promising antiviral agents against IBV Taiwan isolates.