PDF(Pubmed)
Abstract：
Porcine reproductive and respiratory syndrome virus (PRRSV) is an economically important pathogen that has devastated the worldwide swine industry for over 30 years. Autophagy is an evolutionarily conserved intracellular lysosomal degradation pathway, and previous studies have documented that PRRSV infection prompts autophagosome accumulation. However, whether PRRSV induces complete or incomplete autophagy remains controversial. Here, we demonstrated that overexpression of PRRSV nonstructural protein 5 (nsp5) induced the accumulation of autophagosomes, and a similar scenario was observed in PRRSV-infected cells. Moreover, both PRRSV infection and nsp5 overexpression activated incomplete autophagy, as evidenced by the blockage of autophagosome-lysosome fusion. Mechanistically, nsp5 overexpression, as well as PRRSV infection, inhibited the interaction of syntaxin 17 (STX17) with synaptosomal-associated protein 29 (SNAP29), two SNARE proteins that mediate autophagosome fusion with lysosomes, to impair the formation of autolysosomes. We further confirmed that nsp5 interacted with STX17, rather than SANP29, and the interacting domains of STX17 were the N-terminal motif and SNARE motif. Taken together, the findings of our study suggest a mechanism by which PRRSV induces incomplete autophagy by blocking autophagosome degradation and provide insights into the development of new therapeutics to combat PRRSV infection. IMPORTANCE A substantial number of viruses have been demonstrated to utilize or hijack autophagy to benefit their replication. In the case of porcine reproductive and respiratory syndrome virus (PRRSV), previous studies have demonstrated the proviral effects of autophagy on PRRSV proliferation. Thus, an investigation of the mechanism by which PRRSV regulates the autophagy processes can provide new insight into viral pathogenesis. Autophagic flux is a dynamic process that consists of autophagosome formation and subsequent lysosomal degradation. However, the exact effect of PRRSV infection on the autophagic flux remains disputed. In this study, we demonstrated that PRRSV infection, as well as PRRSV nsp5 overexpression, inhibited the interaction of STX17 with SNAP29 to impair the fusion of autophagosomes with lysosomes, thereby blocking autophagic flux. This information will help us to understand PRRSV-host interactions and unravel new targets for PRRS prevention and control.
摘要：
猪繁殖与呼吸综合征病毒（PRRSV）是一种经济上重要的病原体，30多年来一直困扰着全球养猪业。自噬是一种进化保守的细胞内溶酶体降解途径,和以前的研究已经证明PRRSV感染促进自噬体积累。然而,PRRSV诱导完全自噬还是不完全自噬仍存在争议.这里,我们证明了PRRSV非结构蛋白5（nsp5）的过表达诱导自噬体的积累，在PRRSV感染的细胞中观察到类似的情况。此外，PRRSV感染和nsp5过表达都激活了不完全自噬，自噬体-溶酶体融合的阻断证明了这一点。机械上,nsp5过表达，以及PRRSV感染，抑制突触体蛋白17（STX17）与突触体相关蛋白29（SNAP29）的相互作用，两种介导自噬体与溶酶体融合的SNARE蛋白，损害自体溶酶体的形成。我们进一步证实nsp5与STX17而不是SANP29相互作用，并且STX17的相互作用结构域是N末端基序和SNARE基序。一起来看,我们的研究结果提示了PRRSV通过阻断自噬体降解诱导不完全自噬的机制,并为开发对抗PRRSV感染的新疗法提供了见解.重要性已经证明大量病毒利用或劫持自噬来促进其复制。在猪繁殖与呼吸综合征病毒（PRRSV）的情况下，先前的研究已经证明了自噬对PRRSV增殖的前病毒作用。因此，对PRRSV调节自噬过程的机制的研究可以为病毒发病机制提供新的见解.自噬通量是由自噬体形成和随后的溶酶体降解组成的动态过程。然而,PRRSV感染对自噬通量的确切影响仍存在争议。在这项研究中,我们证明PRRSV感染，以及PRRSVnsp5过表达，抑制STX17与SNAP29的相互作用，损害自噬体与溶酶体的融合，从而阻断自噬通量。这些信息将帮助我们了解PRRSV与宿主的相互作用，并揭示PRRS预防和控制的新目标。
