Aged microglia promote peripheral T cell infiltration by reprogramming the microenvironment of neurogenic niches.
Level 5 - mechanism / opinion, no new human data
Preclinical animal and in vitro mechanistic study
PubMed 35879802 · doi:10.1186/s12979-022-00289-6
What was done
Researchers investigated the mechanisms of age-related peripheral T cell infiltration into the central nervous system. Using the subventricular zone of aged mice, cell-cell interaction analyses were conducted to evaluate microglial interactions with CD8+ T cells and brain venous endothelial cells. In addition, cultured human microglia were exposed in vitro to cerebrospinal fluid from elderly individuals.
What was found
The abstract reports qualitative mechanistic findings without exact numerical values: - Subventricular zones of aged mice exhibited chronic inflammation and peripheral T cell infiltration. - Aged microglia secreted CCL3, recruiting peripheral CD8+ memory T cells. - Pro-inflammatory aged microglia secreted TNF-α, which upregulated VCAM1 and ICAM1 expression on brain venous endothelial cells and facilitated T cell transendothelial migration. - In vitro human microglia treated with elderly cerebrospinal fluid adopted a chemotactic phenotype.
Why it matters
The study outlines a specific microglial pathway that reprograms brain vascular and neurogenic microenvironments to facilitate adaptive immune cell entry during aging.
Limits
No quantitative measurements, sample sizes, or statistical metrics are reported in the abstract. Findings are predominantly from rodent models and in vitro cultures, requiring validation in human brain tissue.
Cited by
- supports During aging, cerebral endothelial cells upregulate cell adhesion molecules that recruit immune cells from the blood into the brain.