Pro-inflammatory cytokines derived from West Nile virus (WNV)-infected SK-N-SH cells mediate neuroinflammatory markers and neuronal death

J Neuroinflammation. 2010 Oct 31;7:73. doi: 10.1186/1742-2094-7-73.


Background: WNV-associated encephalitis (WNVE) is characterized by increased production of pro-inflammatory mediators, glial cells activation and eventual loss of neurons. WNV infection of neurons is rapidly progressive and destructive whereas infection of non-neuronal brain cells is limited. However, the role of neurons and pathological consequences of pro-inflammatory cytokines released as a result of WNV infection is unclear. Therefore, the objective of this study was to examine the role of key cytokines secreted by WNV-infected neurons in mediating neuroinflammatory markers and neuronal death.

Methods: A transformed human neuroblastoma cell line, SK-N-SH, was infected with WNV at multiplicity of infection (MOI)-1 and -5, and WNV replication kinetics and expression profile of key pro-inflammatory cytokines were analyzed by plaque assay, qRT-PCR, and ELISA. Cell death was measured in SK-N-SH cell line in the presence and absence of neutralizing antibodies against key pro-inflammatory cytokines using cell viability assay, TUNEL and flow cytometry. Further, naïve primary astrocytes were treated with UV-inactivated supernatant from mock- and WNV-infected SK-N-SH cell line and the activation of astrocytes was measured using flow cytometry and ELISA.

Results: WNV-infected SK-N-SH cells induced the expression of IL-1β, -6, -8, and TNF-α in a dose- and time-dependent manner, which coincided with increase in virus-induced cell death. Treatment of cells with anti-IL-1β or -TNF-α resulted in significant reduction of the neurotoxic effects of WNV. Furthermore treatment of naïve astrocytes with UV-inactivated supernatant from WNV-infected SK-N-SH cell line increased expression of glial fibrillary acidic protein and key inflammatory cytokines.

Conclusion: Our results for the first time suggest that neurons are one of the potential sources of pro-inflammatory cytokines in WNV-infected brain and these neuron-derived cytokines contribute to WNV-induced neurotoxicity. Moreover, cytokines released from neurons also mediate the activation of astrocytes. Our data define specific role(s) of WNV-induced pro-inflammatory cytokines and provide a framework for the development of anti-inflammatory drugs as much-needed therapeutic interventions to limit symptoms associated with WNVE.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Biomarkers / metabolism*
  • Cell Death*
  • Cytokines / immunology*
  • Humans
  • Inflammation* / immunology
  • Inflammation* / pathology
  • Inflammation* / virology
  • Interleukin-1beta / immunology
  • Neuroblastoma / pathology
  • Neuroblastoma / virology
  • Neurons* / immunology
  • Neurons* / pathology
  • Neurons* / virology
  • Tumor Necrosis Factor-alpha / immunology
  • West Nile Fever / immunology
  • West Nile virus / immunology*


  • Biomarkers
  • Cytokines
  • Interleukin-1beta
  • Tumor Necrosis Factor-alpha