PRRSV感染原代和传代PAM的比较转录组学分析

Comparative transcriptomics analysis of primary and immortalized porcine alveolar macrophage infected with PRRSV

猪繁殖与呼吸综合征病毒(porcine reproductive and respiratory syndrome virus,PRRSV)是严重危害世界养猪业的重要病原。PRRSV对原代猪肺泡巨噬细胞(porcine alveolar macrophage,PAM)和传代猪肺泡巨噬细胞系(immortalized porcine alveolar macrophage,IPAM)均易感,但在感染早期,PRRSV在IPAM中的感染率显著高于PAM。为了揭示这2种细胞在PRRSV感染后的应答差异,本研究运用Illumina高通量测序技术对PRRSV感染的IPAM和PAM进行转录组测序,结果表明,PRRSV感染PAM和IPAM后能够诱导相似的免疫应答,但PAM的免疫应答反应更强;与代谢相关的基因在PRRSV感染的IPAM中差异更显著。进一步分析发现,PRRSV感染IPAM后下调细胞周期相关基因的表达水平,导致细胞周期停滞在G0/M期,从而促进PRRSV增殖;IPAM抗原递呈相关基因的缺失或低丰度表达可能是IPAM中免疫应答水平较低的原因;Nod-like receptor(NLR)、Toll-like receptor(TLR)、Target of rapamycin(TOR)、adenosine 5'monophosphate-activated protein kinase(AMPK)和phosphatidylinositol 3-kinase-protein kinase B(PI3K-Akt)等信号通路在PRRSV感染的PAM和IPAM中激活状态不同,可能导致了PRRSV在这2种细胞中的增殖差异。本研究结果为深入了解PRRSV感染原代和传代PAM后的应答差异补充了有用的数据。

The porcine reproductive and respiratory syndrome virus(PRRSV)is an important pathogen that seriously devastates the pig industry worldwide.Both primary porcine alveolar macrophage(PAM)and immortalized PAM(IPAM)are highly susceptible and permissive to PRRSV infection,with significantly higher infection rate in IPAM than PAM during the early stage of PRRSV infection.To identify the differences in the responses of PAM and IPAM to PRRSV infection,RNA-Seq was used to profile PRRSV-infected PAM and IPAM using the Illumina sequencing technology.The data indicated that,(i)though some similar immune responses to PRRSV infection were observed in PAM and IPAM,the immune responses induced in PRRSV-infected PAM were more robust than PRRSV-infected IPAM;(ii)PRRSV-induced genes expression associated with metabolism had more significantly differential expression in IPAM than in PAM.Further analysis showed that the expression levels of genes related to cell cycle were reduced in IPAM with PRRSV infection,causing cell cycle arrest in the G0/M phases,which promotes the proliferation of PRRSV.Furthermore,the absence or low abundance of antigen presentation-related genes in IPAM might result in the lower levels of immune responses under PRRSV infection.Additionally,the activity of signaling pathways such as Nod-like receptor(NLR),Toll-like receptor(TLR),target of rapamycin(TOR),adenosine 5′monophosphate-activated protein kinase(AMPK)and phosphatidylinositol 3-kinase-protein kinase B(PI3 K-Akt)was different in PRRSV-infected PAM and IPAM,which may lead to the differences of PRRSV propagation in PAM and IPAM.Taken together,our study provides data for deeply understanding of the differences in the responses of primary and immortalized PAM to PRRSV infection.