Expression Patterns and Phenotypic Changes Regarding Stemness in Brain Pericytes in Health and Disease

Objective: Brain pericytes (PCs), which exist near endothelial cells, function in processes including maintenance of the blood–brain barrier and as stem cells. However, the relationship between expression patterns and phenotypic changes regarding stemness in brain PCs remains unclear. Thus, we investigated the properties of brain PCs in healthy and diseased mice.Methods: We examined the expression of representative pericytic markers, such as neuron-glial antigen 2 (NG2) and alpha smooth muscle actin (αSMA), and of the stem cell marker Nestin, in developing and pathologic mouse brains.Results: Brain PCs expressed NG2 and αSMA during the embryonic and postnatal stages of development, but rarely during adulthood. Although brain PCs exhibited Nestin expression during early development, it was scarce during adulthood, in parallel with a decrease in pericytic marker expression. However, upon brain injury following ischemic stroke, NG2 and αSMA were significantly induced in PCs in adult mice, concomitant with upregulated Nestin expression.Conclusion: The expression of markers in brain PCs differs during development and between normal and pathologic conditions in addition to traits such as stemness. An understanding of these expression profiles will be useful for PC-based stem cell therapies in the future.