TY - JOUR
T1 - Identification of macrophages in normal and injured mouse tissues using reporter lines and antibodies
AU - Chen, Bijun
AU - Li, Ruoshui
AU - Kubota, Akihiko
AU - Alex, Linda
AU - Frangogiannis, Nikolaos G.
N1 - Funding Information:
Dr Frangogiannis’ laboratory is supported by National Institutes of Health grants R01 HL76246, R01 HL85440, and R01 HL149407, and by U.S. Department of Defense grant PR181464. Dr Chen was supported by AHA post-doctoral award 19POST34460017. Dr Ruoshui Li was sponsored by the China Scholarship Council. Dr Kubota is supported by the Japan Heart Foundation.
Publisher Copyright:
© 2022, The Author(s).
PY - 2022/12
Y1 - 2022/12
N2 - Reliable tools for macrophage identification in mouse tissues are critical for studies investigating inflammatory and reparative responses. Transgenic reporter mice and anti-macrophage antibodies have been used as “specific pan-macrophage” markers in many studies; however, organ-specific patterns of expression and non-specific labeling of other cell types, such as fibroblasts, may limit their usefulness. Our study provides a systematic comparison of macrophage labeling patterns in normal and injured mouse tissues, using the CX3CR1 and CSF1R macrophage reporter lines and anti-macrophage antibodies. Moreover, we tested the specificity of macrophage antibodies using the fibroblast-specific PDGFRα reporter line. Mouse macrophages exhibit organ-specific differences in expression of macrophage markers. Hepatic macrophages are labeled for CSF1R, Mac2 and F4/80, but lack CX3CR1 expression, whereas in the lung, the CSF1R+/Mac2+/Mac3+ macrophage population is not labeled with F4/80. In the splenic red pulp, subpopulations of CSF1R+/F4/80+/Mac3+cells were labeled with Mac2, CX3CR1 and lysozyme M. In the kidney, Mac2, Mac3 and lysozyme M labeled a fraction of the CSF1R+ and CX3CR1+ macrophages, but also stained tubular epithelial cells. In normal hearts, the majority of CSF1R+ and CX3CR1+ cells were not detected with anti-macrophage antibodies. Myocardial infarction was associated with marked expansion of the CSF1R+ and CX3CR1+ populations that peaked during the proliferative phase of cardiac repair, and also expressed Mac2, Mac3 and lysozyme M. In normal mouse tissues, a small fraction of cells labeled with anti-macrophage antibodies were identified as PDGFRα+ fibroblasts, using a reporter system. The population of PDGFRα+ cells expressing macrophage markers expanded following injury, likely reflecting emergence of cellular phenotypes with both fibroblast and macrophage characteristics. In conclusion, mouse macrophages exhibit remarkable heterogeneity. Selection of the most appropriate markers for identification of macrophages in mouse tissues is dependent on the organ and the pathologic condition studied.
AB - Reliable tools for macrophage identification in mouse tissues are critical for studies investigating inflammatory and reparative responses. Transgenic reporter mice and anti-macrophage antibodies have been used as “specific pan-macrophage” markers in many studies; however, organ-specific patterns of expression and non-specific labeling of other cell types, such as fibroblasts, may limit their usefulness. Our study provides a systematic comparison of macrophage labeling patterns in normal and injured mouse tissues, using the CX3CR1 and CSF1R macrophage reporter lines and anti-macrophage antibodies. Moreover, we tested the specificity of macrophage antibodies using the fibroblast-specific PDGFRα reporter line. Mouse macrophages exhibit organ-specific differences in expression of macrophage markers. Hepatic macrophages are labeled for CSF1R, Mac2 and F4/80, but lack CX3CR1 expression, whereas in the lung, the CSF1R+/Mac2+/Mac3+ macrophage population is not labeled with F4/80. In the splenic red pulp, subpopulations of CSF1R+/F4/80+/Mac3+cells were labeled with Mac2, CX3CR1 and lysozyme M. In the kidney, Mac2, Mac3 and lysozyme M labeled a fraction of the CSF1R+ and CX3CR1+ macrophages, but also stained tubular epithelial cells. In normal hearts, the majority of CSF1R+ and CX3CR1+ cells were not detected with anti-macrophage antibodies. Myocardial infarction was associated with marked expansion of the CSF1R+ and CX3CR1+ populations that peaked during the proliferative phase of cardiac repair, and also expressed Mac2, Mac3 and lysozyme M. In normal mouse tissues, a small fraction of cells labeled with anti-macrophage antibodies were identified as PDGFRα+ fibroblasts, using a reporter system. The population of PDGFRα+ cells expressing macrophage markers expanded following injury, likely reflecting emergence of cellular phenotypes with both fibroblast and macrophage characteristics. In conclusion, mouse macrophages exhibit remarkable heterogeneity. Selection of the most appropriate markers for identification of macrophages in mouse tissues is dependent on the organ and the pathologic condition studied.
UR - http://www.scopus.com/inward/record.url?scp=85126668381&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=85126668381&partnerID=8YFLogxK
U2 - 10.1038/s41598-022-08278-x
DO - 10.1038/s41598-022-08278-x
M3 - Article
C2 - 35296717
AN - SCOPUS:85126668381
SN - 2045-2322
VL - 12
JO - Scientific Reports
JF - Scientific Reports
IS - 1
M1 - 4542
ER -