Multiple Protein Kinases via Activation of Transcription Factors NF-κB, AP-1 and C/EBP-δ Regulate the IL-6/IL-8 Production by HIV-1 Vpr in Astrocytes

PLoS One. 2015 Aug 13;10(8):e0135633. doi: 10.1371/journal.pone.0135633. eCollection 2015.

Abstract

Neurocognitive impairments affect a substantial population of HIV-1 infected individuals despite the success of anti-retroviral therapy in controlling viral replication. Astrocytes are emerging as a crucial cell type that might be playing a very important role in the persistence of neuroinflammation seen in patients suffering from HIV-1 associated neurocognitive disorders. HIV-1 viral proteins including Vpr exert neurotoxicity through direct and indirect mechanisms. Induction of IL-8 in microglial cells has been shown as one of the indirect mechanism through which Vpr reduces neuronal survival. We show that HIV-1 Vpr induces IL-6 and IL-8 in astrocytes in a time-dependent manner. Additional experiments utilizing chemical inhibitors and siRNA revealed that HIV-1 Vpr activates transcription factors NF-κB, AP-1 and C/EBP-δ via upstream protein kinases PI3K/Akt, p38-MAPK and Jnk-MAPK leading to the induction of IL-6 and IL-8 in astrocytes. We demonstrate that one of the mechanism for neuroinflammation seen in HIV-1 infected individuals involves induction of IL-6 and IL-8 by Vpr in astrocytes. Understanding the molecular pathways involved in the HIV-1 neuroinflammation would be helpful in the design of adjunct therapy to ameliorate some of the symptoms associated with HIV-1 neuropathogenesis.

Publication types

  • Research Support, N.I.H., Extramural

MeSH terms

  • Astrocytes / enzymology*
  • CCAAT-Enhancer-Binding Proteins / genetics
  • CCAAT-Enhancer-Binding Proteins / metabolism
  • Cell Line
  • Cells, Cultured
  • Gene Expression Regulation / physiology*
  • Gene Products, vpr / genetics
  • Gene Products, vpr / metabolism*
  • HIV-1 / metabolism*
  • Humans
  • Immunohistochemistry
  • Interleukin-6 / genetics
  • Interleukin-6 / metabolism
  • Interleukin-8 / genetics
  • Interleukin-8 / metabolism
  • NF-kappa B / metabolism
  • Reverse Transcriptase Polymerase Chain Reaction
  • Transcription Factor AP-1 / genetics
  • Transcription Factor AP-1 / metabolism
  • Transcription Factors / genetics*
  • Transcription Factors / metabolism*

Substances

  • CCAAT-Enhancer-Binding Proteins
  • Gene Products, vpr
  • Interleukin-6
  • Interleukin-8
  • NF-kappa B
  • Transcription Factor AP-1
  • Transcription Factors