Cyclin-dependent kinase inhibitor 1A mediates mouse line- and fate-dependent cellular responses in Cx3cr1-Cre genetic tools

Ayato Yamasaki; Hayato Shintaku; Akihito Harada; Kazumitsu Maehara; Kaori Tanaka; Mai Saeki; Minako Ito; Hiroyuki Konishi; Makoto Tsuda; Marco Prinz; Yusuke Kishi; Yasuyuki Ohkawa; Shota Yamamoto; Takahiro Masuda

doi:10.1016/j.celrep.2025.116267

Cyclin-dependent kinase inhibitor 1A mediates mouse line- and fate-dependent cellular responses in Cx3cr1-Cre genetic tools

Cell Rep. 2025 Sep 23;44(9):116267. doi: 10.1016/j.celrep.2025.116267. Epub 2025 Sep 9.

Authors

Affiliations

¹ Division of Molecular Neuroimmunology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
² Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan; Division of Multi-Omics, Graduate School of Medical Sciences, Kyushu University, Fukuoka, Japan.
³ Division of Transcriptomics, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
⁴ Laboratory of Molecular Neurobiology, Institute for Quantitative Biosciences, The University of Tokyo, Tokyo, Japan.
⁵ Division of Allergy and Immunology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan.
⁶ Department of Functional Anatomy and Neuroscience, Nagoya University Graduate School of Medicine, Nagoya, Japan; Division of Neuroanatomy, Department of Neuroscience, Yamaguchi University Graduate School of Medicine, Ube, Japan.
⁷ Department of Molecular and System Pharmacology, Graduate School of Pharmaceutical Science, Kyushu University, Fukuoka, Japan.
⁸ Institute of Neuropathology, Medical Faculty, University of Freiburg, Freiburg, Germany; Signalling Research Centres BIOSS and CIBSS, University of Freiburg, Freiburg, Germany.
⁹ Division of Molecular Neuroimmunology, Medical Institute of Bioregulation, Kyushu University, Fukuoka, Japan. Electronic address: takahiro.masuda@bioreg.kyushu-u.ac.jp.

PMID: 40928945
DOI: 10.1016/j.celrep.2025.116267

Abstract

Microglia, the resident macrophages in the central nervous system (CNS), have been intensively studied using rodent genetic models, including the Cre-loxP system. Among them are tamoxifen (TAM)-inducible CX3C chemokine receptor 1 (Cx3cr1)-Cre mouse lines (Cx3cr1^CreERT2), which have enabled in-depth analyses of the biological features and functions of myeloid cells, including microglia. Occasionally, these Cx3cr1^CreERT2 tools have yielded conflicting biological outcomes, the underlying mechanism of which remains unclear. Here, we comparatively characterized the two available Cx3cr1^CreERT2 lines (Cx3cr1^{CreERT2(Litt)} and Cx3cr1^{CreERT2(Jung)}). We find a mouse line-specific and TAM-dependent persistent induction of cyclin-dependent kinase inhibitor 1A (CDKN1A, also known as p21) in microglia of Cx3cr1^{CreERT2(Litt)} mice, but not in those of Cx3cr1^{CreERT2(Jung)} mice, which affects experimental readouts with altered proliferative capacity. Furthermore, aberrant cellular alterations observed in postnatal Cx3cr1^{CreERT2(Litt)} microglia are mitigated by a functional inhibition of CDKN1A. Together, these findings underscore the significance of mouse line-specific phenomena that alter microglial outcomes in a CDKN1A-dependent manner.

Keywords: CP: Cell biology; CP: Neuroscience; Cdkn1a; Cre line; microglia; proliferation.

MeSH terms

Animals
CX3C Chemokine Receptor 1* / genetics
CX3C Chemokine Receptor 1* / metabolism
Cell Proliferation
Cyclin-Dependent Kinase Inhibitor p21* / genetics
Cyclin-Dependent Kinase Inhibitor p21* / metabolism
Integrases* / genetics
Integrases* / metabolism
Mice
Mice, Inbred C57BL
Mice, Transgenic
Microglia* / metabolism
Tamoxifen / pharmacology

Substances

CX3C Chemokine Receptor 1
Integrases
Cx3cr1 protein, mouse
Cyclin-Dependent Kinase Inhibitor p21
Cre recombinase
Tamoxifen
Cdkn1a protein, mouse