The Regulation Of BoHV-1 Infection And The Virus Inflammation Through PLC Signal

Bovine herpesvirus 1(BoHV-1),an important pathogen of Infectious bovine rhinotracheitis(IBR),infects cattle of all ages and breeds worldwide.The clinical symptoms of BoHV-1 infection results in mucositis,reproductive disorders and respiratory inflammation.BoHV-1-induced immune suppression initiates secondary infections of other bacteria and viruses that leading to polymicrobial respiratory tract disease commonly referred to bovine respiratory disease complex(BRDC),which result in enhanced mortality rate.The widely distributed BoHV-1 leads to serious economic losses for the cattle industry worldwide.The Inflammatory response plays an important role in BoHV-1 infection and BRDC.However,it is poorly understood that the mechanisms for BoHV-1 infection induced inflammation.The aim of the study is try to reveal how BoHV-1 infection stimulated inflammation related cell signaling MAPK and the inflammatory mediator reactive oxidative species(ROS).The main studies can be divided into four parts as the following:1.BoHV-1 infection regulates the production of inflammatory mediator ROSROS plays an important role in multiple virus infection and viral-induced inflammatory responses.In this study,the levels of cellular ROS,GSH(glutathione)and mitochondrial membrane potential(MMP)in response to BoHV-1 infection in MDBK cells were measured,respectively.BoHV-1 infection increased ROS production which depended on viral entry,and de novo protein expression and/or DNA replication.Vice versa,excessive ROS was required for efficient viral replication.In addition,BoHV-1 infection decreased cellular GSH,which is a potential mechanism to mediate ROS production,and evidenced that GSH administration could not only individually inhibit viral replication but also synergistically enhance the antiviral effects of ACV when used in combination.Levels of both ATP and MMP were significantly decreased after BHV-1 infection.Interestingly,the loss of MMP was ameliorated by ROS depression.Collectively,ROS dependent mitochondrial damage and ultimately disruption of energy metabolism(ATP depletion)are a potential pathogenic mechanism for BoHV-1 infection.2.BoHV-1 infection stimulates the Inflammation related signaling MAPK pathwaysIt has been reported previously that BoHV-1 infection activates Erkl/2 signaling.However,little is known about the response of p38MAPK and JNK,another MAPK siganling in BoHV-1 infection.We found for the first time that BoHV-1 infection of MDBK cells activated both p38MAPK and JNK pathways.However,only the JNK pathway was essential to viral replication.Interestingly,BoHV-1 activated the MAPK pathways with a ROS-independent mechanism,which was different from that by HSV-1.These studies partially revealed that BoHV-1 infection stimulated MAPK pathways,with a novol mechanism that is not depend on ROS.3.PLC signaling is stimulated by multiple inflammatory stimulatorsA wide range of biological processes are controlled by phospholipase C(PLC)/Ca2+ signaling,which could be blocked by PLC-specific inhibitor U73122.Monocytes/macrophages play an important role in the inflammatory response.In this study,human promonocytic cell line U937 cells which could be differentiated into macrophages dU937 with inducement of phorbol-12-myristate-13-acetate(PMA)were used as a model to investigate the role of PLC in Monocytes/macrophages differentiation,the expression of inflammatory cytokines induced by LPS and influenza A virus H1N1/PR8.We demonstrated that U73122 inhibited PMA-induced,in vitro,differentiation of U937 cells into macrophages as reflected by the reduction of cell adherence and the decreased expression of macrophage specific marker CD 163.It is possible that U73122 blocked PMA-induced adhesion of U937 cells partially by decreased the steady state level and/or inactivation of Pyk2 and paxillin signaling.U73122 inhibited the expression of LPS-induced pro-inflammatory cytokines TNF-a and IL-1? in both dU937 cells and mouse primary peritoneal macrophages,the expression of TNF-a,IL-6,MIP-1? induced by H1N1 infection.These results suggest that PLC is involved in the sophisticated inflammatory response by multiple stimulators.4.BoHV-1 infection regulates PLC signaling to mediate the stimulation of inflammatory signaling or meleculor ROSIn this study,the role of PLC signaling in BoHV-1 infection is investigated.We demonstrated that BoHV-1 infection activated PLC signaling not only for efficient viral replication,but also increasing ROS generation and activation of Erkl/2 and p38MAPK signaling.These data collectively suggested that BoHV-1 regulated the generation of ROS and stimulation of Erkl/2 and p38MAPK signaling with PLC signaling dependent mechanism.So,PLC signaling was important for BoHV-1 infection and the virus induced inflammation.