Proinflammatory cytokines and HIV-1 synergistically enhance CXCL10 expression in human astrocytes

Glia. 2009 May;57(7):734-43. doi: 10.1002/glia.20801.

Abstract

HIV encephalitis (HIVE), the pathologic correlate of HIV-associated dementia (HAD) is characterized by astrogliosis, cytokine/chemokine dysregulation, and neuronal degeneration. Increasing evidence suggests that inflammation is actively involved in the pathogenesis of HAD. In fact, the severity of HAD/HIVE correlates more closely with the presence of activated glial cells than with the presence and amount of HIV-infected cells in the brain. Astrocytes, the most numerous cell type within the brain, provide an important reservoir for the generation of inflammatory mediators, including interferon-gamma inducible peptide-10 (CXCL10), a neurotoxin and a chemoattractant, implicated in the pathophysiology of HAD. Additionally, the proinflammatory cytokines, IFN-gamma and TNF-alpha, are also markedly increased in CNS tissues during HIV-1 infection. In this study, we hypothesized that the interplay of host cytokines and HIV-1 could lead to enhanced expression of the toxic chemokine, CXCL10. Our findings demonstrate a synergistic induction of CXCL10 mRNA and protein in human astrocytes exposed to HIV-1 and the proinflammatory cytokines. Signaling molecules, including JAK, STATs, MAPK (via activation of Erk1/2, AKT, and p38), and NF-kappaB were identified as instrumental in the synergistic induction of CXCL10. Understanding the mechanisms involved in HIV-1 and cytokine-mediated up-regulation of CXCL10 could aid in the development of therapeutic modalities for HAD.

Publication types

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

MeSH terms

  • Astrocytes / immunology
  • Astrocytes / metabolism*
  • Astrocytes / virology
  • Blotting, Western
  • Cell Line
  • Chemokine CXCL10 / genetics
  • Chemokine CXCL10 / metabolism*
  • Cytokines / metabolism*
  • Enzyme-Linked Immunosorbent Assay
  • Gene Expression
  • HIV-1 / physiology*
  • Humans
  • Immunohistochemistry
  • Interferon-gamma / metabolism
  • NF-kappa B / metabolism
  • Polymerase Chain Reaction
  • RNA, Messenger / genetics
  • RNA, Messenger / metabolism
  • Signal Transduction
  • Tumor Necrosis Factor-alpha / metabolism

Substances

  • CXCL10 protein, human
  • Chemokine CXCL10
  • Cytokines
  • NF-kappa B
  • RNA, Messenger
  • Tumor Necrosis Factor-alpha
  • Interferon-gamma