College of Veterinary Medicine, Northwest A&F University, Yangling, 712100, Shaanxi, China.
Vet Res. 2023 Mar 22;54(1):27. doi: 10.1186/s13567-023-01158-w.
Porcine epidemic diarrhoea (PED) caused by porcine epidemic diarrhoea virus (PEDV) has led to significant economic losses in the swine industry worldwide. Histone Cluster 2, H2BE (HIST2H2BE), the main protein component in chromatin, has been proposed to play a key role in apoptosis. However, the relationship between H2BE and PEDV remains unclear. In this study, H2BE was shown to bind and interact with PEDV nonstructural protein 9 (Nsp9) via immunoprecipitation-mass spectrometry (IP-MS). Next, we verified the interaction of Nsp9 with H2BE by immunoprecipitation and immunofluorescence. H2BE colocalized with Nsp9 in the cytoplasm and nuclei. PEDV Nsp9 upregulated the expression of H2BE by inhibiting the expression of IRX1. We demonstrated that overexpression of H2BE significantly promoted PEDV replication, whereas knockdown of H2BE by small interfering RNA (siRNA) inhibited PEDV replication. Overexpression of H2BE led to significantly inhibited GRP78 expression, phosphorylated PERK (p-PERK), phosphorylated eIF2 (p-eIF2), phosphorylated IRE1 (p-IRE1), and phosphorylated JNK (p-JNK); negatively regulated CHOP and Bax expression and caspase-9 and caspase-3 cleavage; and promoted Bcl-2 production. Knocking down H2BE exerted the opposite effects. Furthermore, we found that after deletion of amino acids 1-28, H2BE did not promote PEDV replication. In conclusion, these studies revealed the mechanism by which H2BE is associated with ER stress-mediated apoptosis to regulate PEDV replication. Nsp9 upregulates H2BE. H2BE plays a role in inhibiting apoptosis and thus facilitating viral replication, which depends on the N-terminal region of H2BE (amino acids 1-28). These findings provide a reference for host-PEDV interactions and offer the possibility for developing strategies for PEDV decontamination and prevention.
猪流行性腹泻（PED）由猪流行性腹泻病毒（PEDV）引起，给全球养猪业造成了重大经济损失。组蛋白簇 2，H2BE（HIST2H2BE），染色质中的主要蛋白质成分，被认为在细胞凋亡中发挥关键作用。然而，H2BE 与 PEDV 之间的关系尚不清楚。在这项研究中，通过免疫沉淀-质谱（IP-MS）显示 H2BE 与 PEDV 非结构蛋白 9（Nsp9）结合并相互作用。接下来，我们通过免疫沉淀和免疫荧光验证了 Nsp9 与 H2BE 的相互作用。H2BE 与 Nsp9 在细胞质和核内共定位。PEDV Nsp9 通过抑制 IRX1 的表达而上调 H2BE 的表达。我们证明，H2BE 的过表达显著促进了 PEDV 的复制，而小干扰 RNA（siRNA）敲低 H2BE 则抑制了 PEDV 的复制。H2BE 的过表达导致 GRP78 表达显著抑制，磷酸化 PERK（p-PERK）、磷酸化 eIF2（p-eIF2）、磷酸化 IRE1（p-IRE1）和磷酸化 JNK（p-JNK）；负调控 CHOP 和 Bax 的表达以及 caspase-9 和 caspase-3 的切割；并促进 Bcl-2 的产生。敲低 H2BE 则产生相反的效果。此外，我们发现，在删除氨基酸 1-28 后，H2BE 不再促进 PEDV 复制。总之，这些研究揭示了 H2BE 与内质网应激介导的细胞凋亡相关，从而调节 PEDV 复制的机制。Nsp9 上调 H2BE。H2BE 抑制细胞凋亡，从而促进病毒复制，这依赖于 H2BE 的 N 端区域（氨基酸 1-28）。这些发现为宿主-PEDV 相互作用提供了参考，并为开发 PEDV 去污和预防策略提供了可能性。
