Regenerative potential of the brain: composition and forming of regulatory microenvironment in neurogenic niches

Abstract

An important mechanism of neuronal plasticity is neurogenesis,which occurs during the embryonic period, forming the brainand its structure, and in the postnatal period, providing repairprocesses and participating in the mechanisms of memoryconsolidation. Adult neurogenesis in mammals, includinghumans, is limited in two specific brain areas, the lateral wallsof the lateral ventricles (subventricular zone) and the granularlayer of the dentate gyrus of the hippocampus (subgranularzone). Neural stem cells (NSC), self-renewing, multipotentprogenitor cells, are formed in these zones. Neural stem cells arecapable of differentiating into the basic cell types of the nervoussystem. In addition, NSC may have neurogenic features andnon-specific non-neurogenic functions aimed at maintainingthe homeostasis of the brain. The microenvironment formedin neurogenic niches has importance maintaining populationsof NSC and regulating differentiation into neural or glial cellsvia cell-to-cell interactions and microenvironmental signals.The vascular microenvironment in neurogenic niches areintegrated by signaling molecules secreted from endothelialcells in the blood vessels of the brain or by direct contact withthese cells. Accumulation of astrocytes in neurogenic nichesif also of importance and leads to activation of neurogenesis.Dysregulation of neurogenesis contributes to the formation ofneurological deficits observed in neurodegenerative diseases.Targeting regulation of neurogenesis could be the basis of newprotocols of neuroregeneration.

Keywords

• neurogenesis in the adult brain
• neurogenic niche
• microenvironment
• dysregulation of neurogenesis