Abstract：
Swine influenza virus (SIV) not only brings about great economic losses on the global pig industry, it also poses a significant threat to the public health for its interspecies transmission capacity. Porcine β-defensin 2 (PBD-2) is a host defense peptide and our previous study has shown that PBD-2 inhibits proliferation of enveloped pseudorabies virus both in vitro and in transgenic (TG) mice. The aim of this study is to investigate the possible anti-SIV ability of PBD-2 in a TG pig model created in our previous study. The in-contact challenge trial demonstrated that overexpression of PBD-2 in pigs could efficiently alleviate SIV-associated clinical signs. The SIV titers quantified by EID50 in lung tissues of infected TG pigs were significantly lower than that of wild-type littermates. In vitro, the cell viability assay revealed that PBD-2 mainly interfered with viral entry and post-infection stages. It was further confirmed that PBD-2 could enter porcine tracheal epithelial cells. The proteins interacting with PBD-2 inside host cells were identified with immunoprecipitation and the pathways involved were analyzed. Results showed that PBD-2 could interact with pro-apoptotic solute carrier family 25 member 4 (SLC25A4), also known as adenine nucleotide translocase 1, and thereby inhibited SIV-induced cell apoptosis. The molecular docking analysis suggested that PBD-2 interacted with porcine SLC25A4 mainly through strong hydrogen binding, with the predicted binding affinity being -13.23 kcal/mol. Altogether, these indicate that PBD-2 protects pigs against SIV infection, which may result from its role as a SLC25A4 blocker to alleviate cell apoptosis, providing a novel therapeutic and prophylactic strategy of using PBD-2 to combat SIV.
摘要：
猪流感病毒(SIV)不仅给全球养猪业带来巨大的经济损失,它的种间传播能力也对公众健康构成重大威胁。猪β-防御素2（PBD-2）是一种宿主防御肽，我们先前的研究表明，PBD-2在体外和转基因（TG）小鼠中均抑制包膜伪狂犬病病毒的增殖。这项研究的目的是研究PBD-2在我们先前研究中创建的TG猪模型中可能的抗SIV能力。接触攻击试验表明，PBD-2在猪中的过表达可以有效缓解SIV相关的临床症状。在感染的TG猪的肺组织中通过EID50定量的SIV滴度显着低于野生型同窝动物。体外，细胞活力测定显示PBD-2主要干扰病毒进入和感染后阶段。进一步证实PBD-2可以进入猪气管上皮细胞。用免疫沉淀法鉴定与宿主细胞内PBD-2相互作用的蛋白质，并分析所涉及的途径。结果表明，PBD-2可以与促凋亡溶质载体家族25成员4（SLC25A4）相互作用，也称为腺嘌呤核苷酸转位酶1，从而抑制SIV诱导的细胞凋亡。分子对接分析表明,PBD-2与猪SLC25A4主要通过强氢键作用,预测的结合亲和力为-13.23kcal/mol。总之,这些表明PBD-2保护猪免受SIV感染，这可能是由于其作为SLC25A4阻断剂减轻细胞凋亡的作用，提供了一种使用PBD-2对抗SIV的新的治疗和预防策略。
