Potential caveats of putative microglia-specific markers for assessment of age-related cerebrovascular neuroinflammation
- PDF / 4,465,704 Bytes
- 13 Pages / 595.276 x 790.866 pts Page_size
- 25 Downloads / 148 Views
(2020) 17:366
RESEARCH
Open Access
Potential caveats of putative microgliaspecific markers for assessment of agerelated cerebrovascular neuroinflammation Pedram Honarpisheh1,2 , Juneyoung Lee1 , Anik Banerjee1,2 , Maria P. Blasco-Conesa1 , Parisa Honarpisheh1 , John d’Aigle1, Abdullah A. Mamun1 , Rodney M. Ritzel3 , Anjali Chauhan1, Bhanu P. Ganesh1 and Louise D. McCullough1*
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. Keywords: Microglia, Neuroinflammation, Stroke, Cerebral amyloid angiopathy, Aging, Tmem119, P2RY12, CD45, Brain infiltrating myeloid cells
Introduction Resident microglia (MG) and infiltrating myeloid cells play a cooperative role in the initiation and resolution of inflammation after central nervous system (CNS) injuries [1]. Until recently, the ability to distinguish MG from * Correspondence: [email protected] 1 Department of Neurology, University of Texas John P. and Kathrine G. McGovern Medical School, Houston, TX, USA Full list of author information is available at the end of the article
infiltrating myeloid cells was constrained by the lack of cellspecific surface markers [1]. Inevitably, methods to distinguish MG from other CNS myeloid populations relied on morphological distinctions, generation of bone marrow chimeras, or relative expression of the common leukocyte antigen, also known as cluster of differentiation 45 (CD45) surface marker by flow cytometry [2–5]. CD45
Data Loading...
