Authors: Francesca Lake
NIH researchers have published findings demonstrating that the perivascular cell population that covers blood vessels on the brain surface and contributes to brain protection is derived from endothelial cells, as opposed to immune cells as previously thought. The research, performed in zebrafish, could have implications for a variety of brain disorders.
The cell population is formed of fluorescent granular perithelial cells (FGPs), also known as perivascular macrophages (PVMs) or ‘Mato Cells’. The cells are little understood and it remains unclear whether FGPs and PVMs are one and the same. Recent research has suggested these cells play an important role in scavenging toxins, brain vascular permeability regulation and metabolic function. It was previously thought that these cells were bone marrow-derived macrophages.
“At this point it is still unclear whether PVMs and FGPs are the same cells, or if FGPs represent a specialized brain sub-population of PVMs,” commented the authors.
FGPs are thought to be an important entry point to the brain for HIV. Furthermore, age-related decline in cognitive function has been associated with a decline in FGP function. Learning more about the cell population is therefore of interest for research into a variety of brain disorders and conditions, such as dementia.
The team sought to learn more about this cell population by live-imaging what was identified as the zebrafish equivalent. The zebrafish FGP population was not derived from hematopoietic progenitors, but from the endothelium of the optic choroid vascular plexus. They also analyzed their gene expression, showing the cells related to lymphatic or lympho-venous endothelial cells.
The researchers now hope to conduct study to further understand FGP interaction with blood vessels and the blood–brain barrier. “The zebrafish provides a superb model for further functional characterization of this novel and unusual perivascular cell type,” they concluded.
Sources: Galanternik MV, Castranova D, Gore AV et al. A novel perivascular cell population in the zebrafish brain. eLife doi: 10.7554/eLife.24369 (2017); www.nih.gov/news-events/news-releases/nih-researchers-trace-origin-blood-brain-barrier-sentry-cells