An overlooked subset of Cx3cr1 wt/wt microglia in the Cx3cr1 CreER-Eyfp/wt mouse has a repopulation advantage over Cx3cr1 CreER-Eyfp/wt microglia following microglial depletion

Journal of Neuroinflammation

Harald Lund¹  Xing-Mei Zhang¹  Robert A. Harris¹  Jinming Han¹  Keying Zhu¹  Changlian Zhu²  Christer Betsholtz³  Ying Sun³  Martin Enge⁴  Huaitao Cheng⁴  Volker M Lauschke⁵  Wei Han⁶  Shinobu Goto⁶  Dong Liang⁶  Cuicui Xie⁶  Nageswara Rao Boggavarapu⁶  Yuyu Wang⁶  Asuka Tachi⁶  Klas Blomgren⁶  Ahmed M. Osman⁶  Kristina Gemzell-Danielsson⁶  Kai Zhou⁷  Bertrand Joseph⁸ 

[1] Applied Immunology and Immunotherapy, Department of Clinical Neuroscience, Karolinska Institutet, Center for Molecular Medicine, Karolinska University Hospital;Centre for Brain Repair and Rehabilitation, Institute of Neuroscience and Physiology, University of Gothenburg;Department of Immunology, Genetics and Pathology, Rudbeck Laboratory, Uppsala University;Department of Oncology-Pathology, Karolinska Institutet;Department of Physiology and Pharmacology, Karolinska Institutet;Department of Women’s and Children’s Health, Karolinska Institutet;Henan Neurodevelopment Engineering Research Center for Children, Children’s Hospital Affiliated to Zhengzhou University;Institute of Environmental Medicine, Karolinska Institutet;

关键词: Microglia;    Cre;    GFP;    YFP;    Cx3cr1;    Microglial depletion;   

DOI  :  10.1186/s12974-022-02381-6

来源: DOAJ

【 摘 要 】

Abstract Background Fluorescent reporter labeling and promoter-driven Cre-recombinant technologies have facilitated cellular investigations of physiological and pathological processes, including the widespread use of the Cx3cr1 CreER-Eyfp/wt mouse strain for studies of microglia. Methods Immunohistochemistry, Flow Cytometry, RNA sequencing and whole-genome sequencing were used to identify the subpopulation of microglia in Cx3cr1 CreER-Eyfp/wt mouse brains. Genetically mediated microglia depletion using Cx3cr1 CreER-Eyfp/wt Rosa26 DTA/wt mice and CSF1 receptor inhibitor PLX3397 were used to deplete microglia. Primary microglia proliferation and migration assay were used for in vitro studies. Results We unexpectedly identified a subpopulation of microglia devoid of genetic modification, exhibiting higher Cx3cr1 and CX3CR1 expression than Cx3cr1 CreER-Eyfp/wt Cre + Eyfp + microglia in Cx3cr1 CreER-Eyfp/wt mouse brains, thus termed Cx3cr1 high Cre − Eyfp − microglia. This subpopulation constituted less than 1% of all microglia under homeostatic conditions, but after Cre-driven DTA-mediated microglial depletion, Cx3cr1 high Cre − Eyfp − microglia escaped depletion and proliferated extensively, eventually occupying one-third of the total microglial pool. We further demonstrated that the Cx3cr1 high Cre − Eyfp − microglia had lost their genetic heterozygosity and become homozygous for wild-type Cx3cr1. Therefore, Cx3cr1 high Cre − Eyfp − microglia are Cx3cr1 wt/wt Cre − Eyfp −. Finally, we demonstrated that CX3CL1–CX3CR1 signaling regulates microglial repopulation both in vivo and in vitro. Conclusions Our results raise a cautionary note regarding the use of Cx3cr1 CreER-Eyfp/wt mouse strains, particularly when interpreting the results of fate mapping, and microglial depletion and repopulation studies.

【 授权许可】

Unknown