Hippocampal adult neurogenesis: Does the immune system matter?

J Neurol Sci. 2017 Jan 15;372:482-495. doi: 10.1016/j.jns.2016.10.052. Epub 2016 Nov 3.


Adult hippocampal neurogenesis involves proliferation, survival, differentiation and integration of newborn neurons into pre-existing neuronal networks. Although its functional significance in the central nervous system (CNS) has not comprehensively elucidated, adult neurogenesis has been attributed a role in cognition, learning and memory. There is a growing body of evidence that CNS resident as well as peripheral immune cells participate in regulating hippocampal adult neurogenesis. Microglial cells are closely associated with neural stem/progenitor cell (NSPC) in the neurogenic niche engaged in a bidirectional communication with neurons, which may be important for adult neurogenesis. Microglial and neuronal crosstalk is mediated in part by CX3CL1/CX3CR1 signaling and a disruption in this pathway has been associated with impaired neurogenesis. It has been also reported that microglial neuroprotective or neurotoxic effects in adult neurogenesis occur in a context-dependent manner. Apart from microglia other brain resident and peripheral immune cells including pericytes, perivascular macrophages, mast cells and T-cells also modulate this phenomenon. It is worth mentioning that under some physiological circumstances such as normal aging there is a significant decrease in hippocampal neurogenesis. A role for innate and adaptive immune system in adult neurogenesis has been also reported during aging. Here, we review the current evidence regarding neuro-immune interactions in the regulation of neurogenesis under distinct conditions, including aging.

Keywords: Aging; Fracktalkine; Microglia; Newborn neurons; T-cells.

Publication types

  • Review

MeSH terms

  • Animals
  • Cell Proliferation / physiology
  • Hippocampus / cytology*
  • Humans
  • Immune System / physiology*
  • Neural Stem Cells / physiology
  • Neurogenesis / physiology*