TY - JOUR
T1 - TLR signaling controls lethal encephalitis in WNV-infected brain
AU - Sabouri, Amir H.
AU - Marcondes, Maria Cecilia Garibaldi
AU - Flynn, Claudia
AU - Berger, Michael
AU - Xiao, Nengming
AU - Fox, Howard S.
AU - Sarvetnick, Nora E.
N1 - Publisher Copyright:
© 2014 Elsevier B.V. All rights reserved.
PY - 2014
Y1 - 2014
N2 - Toll-like receptors (TLRs) are known to be activated in Central Nervous System (CNS) viral infections and are recognized to be a critical component in innate immunity. Several reports state a role for particular TLRs in various CNS viral infections. However, excessive TLR activation was previously reported by us in correlation with a pathogenic, rather than a protective, outcome, in a model of SIV encephalitis. Here we aimed at understanding the impact of TLR-mediated pathways by evaluating the early course of pathogenesis in the total absence of TLR signaling during CNS viral infections. We utilized a mouse model of sublethal West Nile virus (WNV) infection. WNV is an emerging neurotropic flavivirus, and a significant global cause of viral encephalitis. The virus was peripherally injected into animals that simultaneously lacked two key adapter molecules of TLR signaling, MyD88 and TRIF. On day 2 pi (post infection), MyD88/Trif-/-mice showed an increased susceptibility to WNV infection, and revealed an impairment in innate immune cytokines, when compared to wild type mice (WT). By day 6 pi, there was an increase in viral burden and robust expression of inflammatory cytokines as well as higher cell infiltration into the CNS in MyD88/Trif-/-, when compared to infected WT. A drastic increase in microglia activation, astrogliosis, and inflammatory trafficking were also observed on day 6 pi in MyD88/Trif-/- Our observations show a protective role for TLR signaling pathways in preventing lethal encephalitis at early stages of WNV infection.
AB - Toll-like receptors (TLRs) are known to be activated in Central Nervous System (CNS) viral infections and are recognized to be a critical component in innate immunity. Several reports state a role for particular TLRs in various CNS viral infections. However, excessive TLR activation was previously reported by us in correlation with a pathogenic, rather than a protective, outcome, in a model of SIV encephalitis. Here we aimed at understanding the impact of TLR-mediated pathways by evaluating the early course of pathogenesis in the total absence of TLR signaling during CNS viral infections. We utilized a mouse model of sublethal West Nile virus (WNV) infection. WNV is an emerging neurotropic flavivirus, and a significant global cause of viral encephalitis. The virus was peripherally injected into animals that simultaneously lacked two key adapter molecules of TLR signaling, MyD88 and TRIF. On day 2 pi (post infection), MyD88/Trif-/-mice showed an increased susceptibility to WNV infection, and revealed an impairment in innate immune cytokines, when compared to wild type mice (WT). By day 6 pi, there was an increase in viral burden and robust expression of inflammatory cytokines as well as higher cell infiltration into the CNS in MyD88/Trif-/-, when compared to infected WT. A drastic increase in microglia activation, astrogliosis, and inflammatory trafficking were also observed on day 6 pi in MyD88/Trif-/- Our observations show a protective role for TLR signaling pathways in preventing lethal encephalitis at early stages of WNV infection.
KW - MyD88
KW - Toll-like receptors (TLRs)
KW - Trif
KW - West Nile virus
UR - http://www.scopus.com/inward/record.url?scp=84926208636&partnerID=8YFLogxK
U2 - 10.1016/j.brainres.2014.05.049
DO - 10.1016/j.brainres.2014.05.049
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C2 - 24928618
AN - SCOPUS:84926208636
SN - 0006-8993
VL - 1574
SP - 84
EP - 95
JO - Brain Research
JF - Brain Research
ER -
