Impact Of Enterovirus71Infection On The Expression And Role Of CPTⅡ, PSGL-1and SCARB2in Mice

Impact of enterovirus71infection on the expression and role of carnitine palmitoyltransferase II in mice brain and brain stemBackground:The carnitine palmitoyltransferase (CPT) system has crucial roles in the β-oxidation of long-chain fatty acids, and is a pivotal component of ATP generation through mitochondrial fatty acid oxidation. The rate-limiting step in the importation of long-chain fatty acids into the mitochondria is the transesterification of acyl-coenzyme A (CoA) to acylcarnitine by CPT I, while CPT II changes the imported acylcarnitine back to acyl-CoA. Here we investigated the impact of enterovirus71(EV71) infection on the expression and role of CPT II in mice brain and brain stem to explore the pathophysiology of EV71-associated encephalitis.Methods:48-80one day old ICR mice. ICR mice were inoculated intraperitoneally (i.p.) with EV71, and were sacrificed by aether anesthesia at days5,10and15post infection (p.i.), and day0(before EV71infection), their brain and brain stem were dissected out for determining the number of copies of viral RNA by quantitative real-time PCR (qRT-PCR). Mitochondria detected by electron microscopy. Detection of expression of CPT II by immunohistochemistry, qRT-PCR and western blot. CPT II activity and ATP level were also measured in brain and brain stem cells.Results:In EV71-infected mice, the number of copies of EV71RNA detected at day5p.i. were brain (5.33±0.30log10copies/mg tissue), brain stem (6.20±0.19log10copies/mg tissue). However, the virus was gradually eliminated in later days. Mitochondria undergone a markedly amplitude swelling in brain and brain stem at day5p.i., and shown some recovery from swollen in later. At day5p.i., expression of CPT II decreased, CPT II activity reduced and ATP levels lowed more obviously, and these changes gradually restored to basic normal state at10-15days p.i..Conclusion:Our data suggests that EV71infection impaired mitochondria, reduced the CPT Ⅱ expression and activity, and decreased local ATP level, which might be important factors to trigger the pathomechanism of acute encephalitis in EV71infection, which may be causally related to the severity of disease. The expression and role of P-selectin glycoprotein ligand-1in different tissues of enterovirus71-infected miceBackground:Aim was to elucidate the role of P-selectin glycoprotein ligand-1(PSGL-1) in Enterovirus71(EV71) infection by evaluating the expression of mouse PSGL-1(mPSGL-1) in EV71-infected mice.Methods:66-110one day old ICR mice were divided into infected group (48-80) and control group (18-30). ICR mice were inoculated intraperitoneally (i.p.) with EV71, and were sacrificed by aether anesthesia at days4,8and12post inoculation (p.i.), and day0(before EV71infection), their lung, heart, brain, brainstem, spinal cord and cerebellum were dissected out for determining the number of copies of viral RNA by quantitative real-time PCR (qRT-PCR), detection of expression of mPSGL-1by immunohistochemistry, qRT-PCR and Western blot. Detection of expression of CD4+. CD8+T lymphocyt, macrophagocyt, natural killer cell of tissues by immunohistochemistry. Cytokines quantification by ELISA.Results:Viral loads in central nervous system (CNS) were higher than in lung or/and heart. Expression of mPSGL-1increased more obviously in CNS than in lung or/and heart within a certain period of time, particularly in brain stem and brain. In the tisssues, the expression of mPSGL-1increased, mean while, immunohistochemistry shown that the expression of CD4+、CD8+T lymphocyte, macrophagocyte, natural killer cell also increased. Local TNF-α, IL-6and IL-1β production were consistent with expression of mPSGL-1. Surprisingly, it presented a negative correlation between relative mPSGL-1mRNA level and TNF-α, IL-6and IL-1β levels in local tissues at day4p.i. and at day8p.i.(excluded TNF-α in lung and heart).Conclusion:The elevated local mPSGL-1may be important in the leukocyte recruitment and in host innate immune response against EV71infection. Association of the expression of SCARB2in EV71-infected mice with inflammatory cytokinesBackground:Scavenger receptor class B, member2(SCARB2) participates in early innate immune responses to infection, so our aim was to explore the expression and role of mouse SCARB2(mSCARB2) in different tissues in EV71-infected mice.Methods:78-130one day old ICR mice were divided into infected group (60-100) and control group (18-30). ICR mice were inoculated intraperitoneally (i.p.) with EV710.1ml107.5TCID50/ml. The control mice were injected i.p. with the same volume RD cell lysate. Mice were sacrificed by aether anesthesia at day4,8and12post infection (p.i.), their brain, brainstem, spinal cord, cerebellum, lung and heart were dissected out for determining the number of copies of viral RNA by quantitative real-time PCR (qRT-PCR), detection of expression of mSCARB2by immunohistochemistry, qRT-PCR and Western-blotting. Cytokines quantification by ELISA.Results:The viral loads in central nervous system (CNS) were higher than in lung or/and heart. The expression of mSCARB2increased in tissues of EV71-infected mice, however, the levels of mSCARB2increased in CNS were higher than in lung or/and heart within a certain period of time, particularly in brain stem and brain. In addition, local TNF-a, IL-6and IL-1β levels of production were consistent with mSCARB2levels of expression in tissues of EV71-infected mice. However, it presented a positive correlation between relative mSCARB2mRNA level and TNF-a, IL-6and IL-1β levels in local tissues at day4and8p.i..Conclusion:Our data revealed that the elevated local mSCARB2may modulate pro-inflammatory cytokines induction in local tissues, particularly, in CNS of EV71-infected mice.