Cooperative induction of CXCL10 involves NADPH oxidase: Implications for HIV dementia

Glia. 2010 Apr;58(5):611-21. doi: 10.1002/glia.20949.

Abstract

With the increasing prevalence of HIV-associated neurocognititve disorders (HAND), understanding the mechanisms by which HIV-1 induces neuro-inflammation and subsequent neuronal damage is important. The hallmark features of HIV-encephalitis, the pathological correlate of HIV-associated Dementia (HAD), are gliosis, oxidative stress, chemokine dysregulation, and neuronal damage/death. Since neurons are not infected by HIV-1, the current thinking is that these cells are damaged indirectly by pro-inflammatory chemokines released by activated glial cells. CXCL10 is a neurotoxic chemokine that is upregulated in astroglia activated by HIV-1 Tat, IFN-gamma, and TNF-alpha. In this study we have demonstrated that HIV-1 Tat increases CXCL10 expression in IFN-gamma and TNF-alpha stimulated human astrocytes via NADPH oxidase. We have shown that the treatment of astrocytes with a mixture of Tat and cytokines leads to a respiratory burst that is abrogated by apocynin, an NADPH oxidase inhibitor. Pretreatment of Tat, IFN-gamma, and TNF-alpha stimulated astrocytes with apocynin also resulted in concomitant inhibition of CXCL10 expression. Additionally, apocynin was also able to reduce Tat and cytokine-mediated activation of the corresponding signaling molecules Erk1/2, Jnk, and Akt with a decrease in activation and nuclear translocation of NF-kappaB, important regulators of CXCL10 induction. Understanding the mechanisms involved in reducing both oxidative stress and the release of pro-inflammatory agents could lead to the development of therapeutics aimed at decreasing neuro-inflammation in patients suffering from HAD.

Publication types

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

MeSH terms

  • Acetophenones / pharmacology
  • Astrocytes / drug effects*
  • Astrocytes / metabolism*
  • Cell Line, Transformed
  • Chemokine CXCL10 / metabolism*
  • Drug Interactions
  • Enzyme Inhibitors / pharmacology
  • Enzyme-Linked Immunosorbent Assay
  • Extracellular Signal-Regulated MAP Kinases / metabolism
  • Gene Expression Regulation, Enzymologic / drug effects*
  • Humans
  • Interferon-alpha / pharmacology
  • Interferon-gamma / pharmacology
  • Membrane Glycoproteins / genetics
  • Membrane Glycoproteins / metabolism
  • NADPH Oxidase 2
  • NADPH Oxidases / genetics
  • NADPH Oxidases / metabolism*
  • Oxidative Stress / drug effects
  • Protein Transport / drug effects
  • RNA, Small Interfering / pharmacology
  • Signal Transduction / drug effects
  • tat Gene Products, Human Immunodeficiency Virus / pharmacology*

Substances

  • Acetophenones
  • Chemokine CXCL10
  • Enzyme Inhibitors
  • Interferon-alpha
  • Membrane Glycoproteins
  • RNA, Small Interfering
  • tat Gene Products, Human Immunodeficiency Virus
  • Interferon-gamma
  • acetovanillone
  • CYBB protein, human
  • NADPH Oxidase 2
  • NADPH Oxidases
  • Extracellular Signal-Regulated MAP Kinases