Fig. 1.

Schematic of the roles of pericytes in neurovascular interactions in healthy and diseased brains. Left: in the healthy brain, pericytes maintain the integrity of the blood-brain barrier (BBB) and regulate cerebral blood flow. Pericytes secrete pleiotrophin (PTN) to support neuronal growth. Right: in Alzheimer’s disease, Aβ oligomers stimulate ROS generation and endothelin-1 release (possibly from pericytes), which in turn activates pericyte ET_A receptors (ET_AR), leading to capillary constriction and cerebral blood flow reduction. Degeneration of pericytes causes BBB breakdown, plasma leakage, and deprivation of PTN, which result in neurodegeneration. An increase of pericyte-derived soluble PDGFRβ (sPDGFRβ) in the CSF is also associated with early cognitive impairment and BBB breakdown.