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Published in: Journal of Neuroinflammation 1/2020

Open Access 01-12-2020 | Stroke | Research

Potential caveats of putative microglia-specific markers for assessment of age-related cerebrovascular neuroinflammation

Authors: Pedram Honarpisheh, Juneyoung Lee, Anik Banerjee, Maria P. Blasco-Conesa, Parisa Honarpisheh, John d’Aigle, Abdullah A. Mamun, Rodney M. Ritzel, Anjali Chauhan, Bhanu P. Ganesh, Louise D. McCullough

Published in: Journal of Neuroinflammation | Issue 1/2020

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Abstract

Background

The ability to distinguish resident microglia from infiltrating myeloid cells by flow cytometry-based surface phenotyping is an important technique for examining age-related neuroinflammation. The most commonly used surface markers for the identification of microglia include CD45 (low-intermediate expression), CD11b, Tmem119, and P2RY12.

Methods

In this study, we examined changes in expression levels of these putative microglia markers in in vivo animal models of stroke, cerebral amyloid angiopathy (CAA), and aging as well as in an ex vivo LPS-induced inflammation model.

Results

We demonstrate that Tmem119 and P2RY12 expression is evident within both CD45int and CD45high myeloid populations in models of stroke, CAA, and aging. Interestingly, LPS stimulation of FACS-sorted adult microglia suggested that these brain-resident myeloid cells can upregulate CD45 and downregulate Tmem119 and P2RY12, making them indistinguishable from peripherally derived myeloid populations. Importantly, our findings show that these changes in the molecular signatures of microglia can occur without a contribution from the other brain-resident or peripherally sourced immune cells.

Conclusion

We recommend future studies approach microglia identification by flow cytometry with caution, particularly in the absence of the use of a combination of markers validated for the specific neuroinflammation model of interest. The subpopulation of resident microglia residing within the “infiltrating myeloid” population, albeit small, may be functionally important in maintaining immune vigilance in the brain thus should not be overlooked in neuroimmunological studies.
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Metadata
Title
Potential caveats of putative microglia-specific markers for assessment of age-related cerebrovascular neuroinflammation
Authors
Pedram Honarpisheh
Juneyoung Lee
Anik Banerjee
Maria P. Blasco-Conesa
Parisa Honarpisheh
John d’Aigle
Abdullah A. Mamun
Rodney M. Ritzel
Anjali Chauhan
Bhanu P. Ganesh
Louise D. McCullough
Publication date
01-12-2020
Publisher
BioMed Central
Keyword
Stroke
Published in
Journal of Neuroinflammation / Issue 1/2020
Electronic ISSN: 1742-2094
DOI
https://doi.org/10.1186/s12974-020-02019-5

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