HIV-1-infected and/or immune-activated macrophages regulate astrocyte CXCL8 production through IL-1beta and TNF-alpha: involvement of mitogen-activated protein kinases and protein kinase R

J Neuroimmunol. 2008 Aug 30;200(1-2):100-10. doi: 10.1016/j.jneuroim.2008.06.015. Epub 2008 Jul 23.

Abstract

Monocyte infiltration is an important pathogenic event in human immunodeficiency virus type one (HIV-1) associated dementia (HAD). CXCL8 (Interleukin 8, IL-8), a CXC chemokine that elicits chemotaxis of neutrophils, has recently been found to recruit monocytes or synergistically enhance CCL2-mediated monocyte migration. In this report, we demonstrate CXCL8 levels in the cerebrospinal fluid of HAD patients are higher than HIV-1 seropositive patients without neurological impairment. The underlying mechanisms regulating CXCL8 production during disease are not completely understood. We investigated the role of HIV-1-infected and immune-competent macrophages, the principal target cell and mediator of neuronal injury in HAD, in regulating astrocyte CXCL8 production. Immune-activated and HIV-1-infected human monocyte-derived-macrophages (MDM) conditioned media (MCM) induced production of CXCL8 by human astrocytes. This CXCL8 production was dependent on MDM IL-1beta and TNF-alpha production following viral and immune activation. CXCL8 production was reduced by inhibitors for mitogen-activated protein kinases (MAPKs), including p38, c-Jun N-terminal kinase (JNK), and extracellular signal-regulated kinases (ERK1/2). Moreover, prolonged IL-1beta or TNF-alpha treatment activated double-stranded RNA-activated protein kinase (PKR). Inhibition of PKR prevented elevated CXCL8 production in astrocytes. We conclude that IL-1beta and TNF-alpha, produced from HIV-1-infected and immune-competent macrophages, are critical in astrocyte CXCL8 production. Multiple protein kinases, including p38, JNK, ERK1/2, and PKR, participate in the inflammatory response of astrocytes. These observations will help to identify effective therapeutic strategies to reduce high-levels of CXCL8-mediated CNS inflammation during HAD.

Publication types

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

MeSH terms

  • Adult
  • Astrocytes / drug effects*
  • Astrocytes / metabolism
  • Astrocytes / virology
  • Brain / cytology
  • Cells, Cultured
  • Culture Media, Conditioned / pharmacology
  • Dose-Response Relationship, Drug
  • Enzyme Inhibitors / pharmacology
  • Enzyme-Linked Immunosorbent Assay
  • Female
  • Fetus / anatomy & histology
  • Gene Expression Regulation, Viral / drug effects
  • HIV Infections* / immunology
  • HIV Infections* / metabolism
  • HIV Infections* / pathology
  • Humans
  • Interleukin-1beta / pharmacology*
  • Interleukin-8 / metabolism*
  • Lipopolysaccharides / pharmacology
  • Macrophages / drug effects*
  • Macrophages / immunology
  • Macrophages / virology
  • Male
  • Middle Aged
  • Mitogen-Activated Protein Kinases / physiology*
  • Protein Kinases / physiology*
  • Tumor Necrosis Factor-alpha / pharmacology*

Substances

  • CXCL8 protein, human
  • Culture Media, Conditioned
  • Enzyme Inhibitors
  • Interleukin-1beta
  • Interleukin-8
  • Lipopolysaccharides
  • Tumor Necrosis Factor-alpha
  • Protein Kinases
  • Mitogen-Activated Protein Kinases