Modulation of Microglial Process Convergence Toward Neuronal Dendrites by Extracellular Calcium

J Neurosci. 2015 Feb 11;35(6):2417-22. doi: 10.1523/JNEUROSCI.3279-14.2015.

Abstract

Extracellular calcium concentrations in the brain fluctuate during neuronal activities and may affect the behavior of brain cells. Microglia are highly dynamic immune cells of the brain. However, the effects of extracellular calcium concentrations on microglial dynamics have not been investigated. Here, we addressed this question in mouse brain slices and in vivo using two-photon microscopy. We serendipitously found that extracellular calcium reduction induced microglial processes to converge at distinct sites, a phenomenon we termed microglial process convergence (MPCs). Our studies revealed that MPCs target neuronal dendrites independent of neuronal action potential firing and is mediated by ATP release and microglial P2Y12 receptors. These results indicate that microglia monitor and interact with neurons during conditions of cerebral calcium reduction in the normal and diseased brain.

Keywords: P2Y12 receptor; calcium reduction; microglia; microglial process convergence; neuronal dendrites.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Calcium / physiology*
  • Calcium Signaling / physiology*
  • Dendrites / physiology*
  • Extracellular Space / physiology
  • Female
  • In Vitro Techniques
  • Male
  • Mice
  • Mice, Knockout
  • Mice, Transgenic
  • Microglia / physiology*
  • Neurons / physiology*
  • Purines / metabolism
  • Receptors, Purinergic P2Y12 / genetics
  • Receptors, Purinergic P2Y12 / physiology

Substances

  • Purines
  • Receptors, Purinergic P2Y12
  • Calcium