Inhibition Of HY12 Replication By Activation Of NLRP3 Inflammasome Signaling Pathway

Bovine enterovirus(BEV),together with Coxsackie virus and poliovirus,is a member of the enterovirus genus within the family of Picornaviridae.BEV can cause infection of cattle characterized by digestive and respiratory disorder,which has caused significant economic losses to cattle industry.Previous studies found that HY12 is highly invasive to ICR mice.After infection,HY12 proliferated in multiple tissues or organs in a short time,and even invaded the central nervous system,causing neurological symptoms.NLRP3 inflammasome,as an important component of innate immunity,could recognize PAMPs and damps produced by a variety of pathogenic microorganisms,and promote the secretion of cytokines such as IL-18 and IL-1β,which mediates the body’s early immunity system.To further explore the mechanism for host to combat the HY12 infection in the early stage of infection,ICR mice and primary peritoneal macrophages were used as models to investigate the role of NLRP3 inflammasome pathway in combating the HY12 infection by using approaches as such Western blot,Q-PCR,gene over-expression and knockdown,immunohistochemistry and immunofluorescence.After infected by HY12,the IL-1β expression was detected 12 hpi both in the serum of ICR mice or the supernatant of macrophages.The IL-1β secretion was increased significantly in a time manners and dose-dependent fashion,indicating that the host promote the secretion of IL-1β after infection by HY12.At the same time,the expression of Caspase-1 and its activated form were also significantly up-regulated in macrophages infected by HY12,while IL-1β secretion decreased significantly in macrophages with Caspase-1 knocked down,which confirmed the crucial role of the Caspase-1 in IL-1β induction by HY12 infection.In addition,the expression and the role of the NLRP3 signaling pathway in host’s combating the virus infection was investigated,and revealed that NLRP3 m RNA and protein levels were significantly increased in macrophage cells infected by HY12,while the expression of IL-1β and activation of caspase-1 were significantly decreased in NLRP3-knockout macrophage infected by HY12,confirming that the activation of NLRP3 signaling pathway led to the activation of caspase-1 and promote IL-1β secretion.Furthermore,the effect of activation of NLRP3 signal pathway on HY12 replication was explored and found that the replication efficiency for HY12 was significantly increased after NLRP3 knockdown,while HY12 replication decreased significantly in NLRP3 overexpression macrophages.In summary,we have employed the cell model and murine model systems to explore the mechanism for host to counter HY12 infection during the early stage and found that host can activate NLRP3 inflammasome signal pathway to inhibit the replication of HY12,which laid a foundation for the exploration of the target molecules for anti-HY12 infection.