Mechanism Of TRIM2 Regulating Innate Immune Response To EV71 Infected Severe Hand,Foot And Mouth Disease

The number of cases and deaths of hand,foot and mouth disease have accounted for the first place in the category C infectious diseases since 2008,and the overall trend is rising.Patients with hand,foot and mouth disease infection usually present herpes in the hand,foot and mouth,or invisible infection,and most of them can heal themselves.However,patients,with severe hand,foot and mouth disease may have severe central nervous system symptoms and serious complications,which seriously endanger the health of infants and young children.The analysis of the influencing factors of severe hand,foot and mouth disease is of great significance for the prevention and treatment of hand,foot and mouth disease,especially severe hand,foot and mouth disease.A growing number of studies have shown that the TRIM protein family plays an important regulatory role in virus-induced innate immune responses.This topic explores the role and mechanism of TRIM2 in the innate immune response triggered by EV71,and provides ideas for the prevention and treatment of EV71 infection in hand,foot and mouth disease.Part I Investigation on the influencing factors of severe hand,foot and mouth disease in ShenzhenObjective To investigate the influencing factors of severe cases of hand,foot and mouth disease in Shenzhen,and provide a scientific reference for preventing the occurrence of severe hand,foot and mouth disease and reducing the damage of hand,foot and mouth disease.Methods The data of mild and severe cases of hand-foot-mouth disease during 2012-2016 in Shenzhen were collected.The single factor χ2 test and multivariate logistic regression analysis was used to analyze the risk factors of severe hand-foot-mouth disease.Results The results of single factor χ2 test showed that 11 factors including gender,age,occupation of children,type of household registration,whether to participate in medical insurance,feeding method,vaccination one month before the onset of the disease,fever,rash,EV71 and CA16 were statistically significant.The results of multivariate logistic regression analysis showed that the diaspora children,fever and EV71 infection were the influencing factors of severe HFMD cases.The OR values(95%CI)were 3.86(1.156-12.987),6.836(2.315-20.184)and 8.746(3.729-20.511),respectively.Part II The role and mechanism of TRIM2 in the innate immune response ofEV71 infection in hand,foot and mouth diseaseObjective EV71 is the major causative agent of HFMD,which induces a significant increase in cytokine and chemokine levels.It can lead to local or systemic inflammation and serious complications,but the underlying regulatory mechanisms and mechanisms of inflammation remain elusive.More and more studies have demonstrated that the TRIM family plays a role in virus-induced innate immunity,whereas the function of TRIM2 in the innate immune system is largely unknown.This study aimed to understand the role and mechanism of TRIM2 in EV71-induced innate immunity,in order to provide a theoretical basis for the clinical treatment of hand-foot-and-mouth disease caused by EV71 infection and the development of drugs and new vaccines.Methods1.The gene chip was used to detect the expression of TRIM family molecules after EV71 infection of THP1 induced differentiation of macrophages(t-M(?)),and TRIM molecules with significant changes in expression were screened.2.The mRNA expression level of TRIM family molecules screened in t-Mo(?)was verified by qPCR.3.After over-expressing TRIM2 or targeting TRIM2 by siRNA in t-M(?),qPCR was used to detect the expression of mRNA of cytokine under EV71 infection4.After over-expressing TRIM2 or targeting TRIM2 by siRNA in t-M(?),Western blot was used to detect the activation of different signaling molecules in the innate immune signaling pathway and the expression level of EV71 structural protein VP1 under EV71 infection.5.Using Co-Immunoprecipitation and Western blot to detect the interaction between TRIM2 and MDA5,and detect the K48-linked polyubiquitination of MDA5 mediating by TRIM2.Results1.TRIM2 expression was decreased after EV71 infection in Thp1-induced macrophages.2.Overexpression of TRIM2 significantly inhibited the production of cytokines IL-6,TNF-α and CCL3 induced by EV71 infection(P<0.05).After down-regulate the expression of TRIM2,the production of cytokines IL-6,TNF-α and CCL3 induced by EV71 infection was significantly increased(P<0.05).3.Overexpression of TRIM2,the activation of signal molecules in the MAPK and NF-κB pathways was inhibited,and EV71 replication was enhanced(P<0.05),After down-regulate the expression of TRIM2,the activation of signaling molecules in the MAPK and NF-κB pathways was enhanced,and EV71 replication was inhibited(P<0.05).4.TRIM2 interacted with MDA5 and promote the K48-linked polyubiquitination of MDA5 leading to its proteasomal degradation,thereby negatively regulating the activation of MAPK and NF-κB signaling pathway.Conclusion1.There are many factors influencing severe hand,foot and mouth disease,Diaspora children,fever,and EV71 infection are risk factors for severe hand,foot and mouth disease.2.TRIM2 interacts with the pattern recognition receptor MDA5 and promote the K48-linked polyubiquitination of MDA5,negatively regulates the activation of innate signaling,inhibits the release of cytokines,leading to the balance of EV71-induced innate immune response.