Journal of NeuroVirology

, Volume 17, Issue 4, pp 327–340

Neurotoxic effects of the HCV core protein are mediated by sustained activation of ERK via TLR2 signaling

  • Amy D. Paulino
  • Kiren Ubhi
  • Edward Rockenstein
  • Anthony Adame
  • Leslie Crews
  • Scott Letendre
  • Ronald Ellis
  • Ian P. Everall
  • Igor Grant
  • Eliezer Masliah
Article

DOI: 10.1007/s13365-011-0039-0

Cite this article as:
Paulino, A.D., Ubhi, K., Rockenstein, E. et al. J. Neurovirol. (2011) 17: 327. doi:10.1007/s13365-011-0039-0

Abstract

Hepatitis C virus (HCV) infection is a serious problem among those co-infected with human immunodeficiency virus; however, its impact in the central nervous system (CNS) remains unclear. This study aimed to investigate the mechanisms underlying HCV core protein-mediated neurodegeneration. Analysis of human HCV seropositive cases demonstrated widespread damage to neuronal dendritic processes and sustained activation of extracellular signal-related kinase (ERK); analogous pathologies were observed in wild type injected with HCV core protein into the hippocampus. In vitro analysis in neuronal cells exposed to HCV core demonstrated retraction of the neuronal processes in an ERK/Signal Transducer and Activator of Transcription 3 (STAT3)-dependent manner dependent on toll-like receptor 2 (TLR2) signaling activation. These results indicate that HCV core protein neurotoxicity may be mediated by the sustained activation of ERK/STAT3 via TLR2-IRAK1 signaling pathway. These pathways provide novel targets for development of neuroprotective treatments for HCV involvement of the CNS.

Keywords

HCVTLR2NeurodegenerationERK

Supplementary material

13365_2011_39_MOESM1_ESM.doc (466 kb)
Supplementary Fig. 1Co-immunoprecipitation studies TLR2/IRAK pathway after HCV core exposure. a Immunoprecipitation with the IRAK1 antibody resulted in the detection of TRAF6 by immunoblot only in neuronal cells treated with HCV core compared to vehicle. b Immunoprecipitation with the TRAF6 antibody resulted in the detection of TAB1 by immunoblot (55 kDa band) in neuronal cells treated with HCV core compared to vehicle. c Immunoprecipitation with the TLR2 antibody resulted in the detection of MyD88 by immunoblot only in HCV core-challenged neuronal cells compared to vehicle controls. These effects were not observed in control experiments where the neuronal cells treated with HCV core were immunoprecipitated with a non-specific IgG (DOC 466 kb)
13365_2011_39_MOESM2_ESM.doc (1.7 mb)
Supplementary Fig. 2HCV core protein toxicity in neuronal cells derived from neuronal precursor cells. a β-tubulin and (b) pERK immunoreactivity in vehicle-treated control neuronal cells. c Co-localization of β-tubulin and pERK immunoreactivity in vehicle-treated control neuronal cells. d β-tubulin and (e) pERK immunoreactivity in HCV core-treated neuronal cells. f Co-localization of β-tubulin and pERK immunoreactivity in HCV core-treated neuronal cells. g β-tubulin and (h) pERK immunoreactivity in inactive HCV core-treated neuronal cells. i Co-localization of β-tubulin and pERK immunoreactivity in inactive HCV core-treated neuronal cells. j β-tubulin and (k) pERK immunoreactivity in HCV NS3-treated neuronal cells. l Co-localization of β-tubulin and pERK immunoreactivity in HCV NS3-treated neuronal cells. m Analysis of pERK immunoreactivity across experimental groups. Scale bar = 30 μM. Asterisk indicates p < 0.05 one-way ANOVA with post hoc Fisher. HCV hepatitis C virus, pERK phospho-extracellular signal-related kinase (DOC 1606 kb)

Copyright information

© Journal of NeuroVirology, Inc. 2011

Authors and Affiliations

  • Amy D. Paulino
    • 1
    • 6
  • Kiren Ubhi
    • 1
  • Edward Rockenstein
    • 1
  • Anthony Adame
    • 1
  • Leslie Crews
    • 2
  • Scott Letendre
    • 3
  • Ronald Ellis
    • 1
  • Ian P. Everall
    • 4
    • 7
  • Igor Grant
    • 4
    • 5
  • Eliezer Masliah
    • 1
    • 2
  1. 1.Department of NeurosciencesUniversity of California San DiegoLa JollaUSA
  2. 2.Department of PathologyUniversity of California San DiegoLa JollaUSA
  3. 3.Department of MedicineUniversity of California San DiegoLa JollaUSA
  4. 4.Department of Psychiatry and the HIV Neurobehavioral Research CenterUniversity of California San DiegoLa JollaUSA
  5. 5.Veterans Affairs Healthcare SystemLa JollaUSA
  6. 6.Neuropore Therapies Inc.San DiegoUSA
  7. 7.Department of PsychiatryUniversity of Melbourne, Level 1 North, Royal Melbourne HospitalMelbourneAustralia