Table 12_The DEAD-box RNA helicase 27 negatively regulates the replication of porcine reproductive and respiratory syndrome virus by mediating GP2a autophagy degradation and inducing interferon-β production.xlsx

Porcine reproductive and respiratory syndrome virus (PRRSV) causes severe economic losses to the swine industry, with its replication and immune evasion mechanisms remaining incompletely understood. While DEAD-box helicases (DDXs) are known to either promote or inhibit viral infections, no prior studies have explored the role of DDX27 in viral pathogenesis. Here, we investigated the role of DDX27 in PRRSV infection. PRRSV infection induced the upregulation of endogenous DDX27 mRNA without affecting protein levels in Marc-145 cells. Functional studies revealed that overexpression of DDX27 significantly inhibited PRRSV N protein and mRNA accumulations, while silencing DDX27 enhanced viral replication. Using yeast two-hybrid and co-immunoprecipitation assays, we identified a specific interaction between DDX27 and the viral structural protein GP2a, but not with GP3, M, or non-structural proteins. Mechanistically, DDX27 promoted GP2a degradation via mediating selective autophagy pathway and activated IFN-β production, thereby suppressing PRRSV replication and enhancing host immune responses. These findings reveal DDX27 as a novel antiviral factor that targets PRRSV through dual mechanisms. This study broadens our understanding of the DDX family’s role in PRRSV infection and highlights DDX27 as a potential therapeutic target for controlling PRRSV.

猪繁殖与呼吸综合征病毒（Porcine reproductive and respiratory syndrome virus, PRRSV）给养猪业造成了严重的经济损失，但其复制与免疫逃逸机制仍未完全阐明。已知DEAD-box解旋酶（DEAD-box helicases, DDXs）可促进或抑制病毒感染，但目前尚无研究探讨DDX27在病毒致病过程中的作用。本研究探究了DDX27在PRRSV感染中的功能。实验结果显示，PRRSV感染可诱导Marc-145细胞中内源性DDX27 mRNA的表达上调，但不影响其蛋白水平。功能实验表明，过表达DDX27可显著抑制PRRSV N蛋白及mRNA的积累，而沉默DDX27则会增强病毒复制。通过酵母双杂交与免疫共沉淀实验，我们证实DDX27可与病毒结构蛋白GP2a发生特异性相互作用，但与GP3、M蛋白及病毒非结构蛋白均无此类相互作用。机制层面的研究显示，DDX27可通过介导选择性自噬通路促进GP2a蛋白降解，并激活干扰素-β（IFN-β）的产生，进而抑制PRRSV复制并增强宿主免疫应答。上述研究结果表明，DDX27是一种通过双重机制靶向PRRSV的新型抗病毒因子。本研究拓展了学界对DDX家族在PRRSV感染中作用的认知，并提示DDX27可作为防控PRRSV的潜在治疗靶点。