When human immunodeficiency virus meets chemokines and microglia: neuroprotection or neurodegeneration?

J Neuroimmune Pharmacol. 2013 Mar;8(1):118-31. doi: 10.1007/s11481-012-9353-4. Epub 2012 Apr 15.

Abstract

Chemokines are chemotactic cytokines that were originally discovered as promoters of leukocyte proliferation and mobility. In recent years, however, evidence has demonstrated constitutive expression of chemokines and chemokine receptors in a variety of cells in the central and peripheral nervous system and has proposed a role for chemokines in neurodegenerative diseases characterized by inflammation and microglia proliferation. In addition, chemokine receptors, and in particular CXCR4 and CCR5, mediate human immunodeficiency virus type 1 (HIV) infection of immunocompetent cells as well as microglia. Subsequently, HIV, through a variety of mechanisms, promotes synapto-dendritic alterations and neuronal loss that ultimately lead to motor and cognitive impairments. These events are accompanied by microglia activation. Nevertheless, a microglia-mediated mechanism of neuronal degeneration alone cannot fully explain some of the pathological features of HIV infected brain such as synaptic simplification. In this article, we present evidence that some of the microglia responses to HIV are beneficial and neuroprotective. These include the ability of microglia to release anti-inflammatory cytokines, to remove dying cells and to promote axonal sprouting.

Publication types

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

MeSH terms

  • AIDS Dementia Complex / pathology
  • Animals
  • Chemokines / physiology*
  • HIV / immunology*
  • HIV Infections / pathology
  • Humans
  • Macrophage Activation / physiology
  • Microglia / immunology*
  • Neurodegenerative Diseases / immunology*
  • Neurodegenerative Diseases / pathology
  • Neurodegenerative Diseases / prevention & control*
  • Receptors, CCR5 / drug effects
  • Receptors, CCR5 / physiology
  • Receptors, CXCR4 / drug effects
  • Receptors, CXCR4 / physiology
  • Viral Proteins / physiology

Substances

  • Chemokines
  • Receptors, CCR5
  • Receptors, CXCR4
  • Viral Proteins