Generation and characterization of a myeloid cell‐specific Cyp19a1 knockout mouse model

Abstract

CYP19A1 (the aromatase) is a key enzyme in the biosynthesis of estrogens. Estrogens have important regulatory functions, including roles as a major mitogenic stimulus for cellular proliferation. It has been proposed that macrophage CYP19A1 can increase estrogen production at sites of tissue injury, thereby influencing the balance between normal tissue repair and pathogenic outcomes such as hyperproliferation and oncogenic transformation following xenobiotic‐induced toxicity. Our goal is to test this hypothesis using a cell‐specific Cyp19a1‐null mouse model. Here we report the generation and initial characterization of a myeloid cell (including macrophage) specific Cyp19a1‐null mouse model. A newly generated Cyp19a1‐lox mouse was intercrossed with a Cre‐transgenic mouse for myeloid cell specific deletion of a critical CYP19A1 exon. Cyp19a1 deletion was confirmed by PCR analysis of genomic DNA isolated from macrophages in lung bronchoalveolar lavage fluid; according to results of a quantitative PCR analysis, the deletion efficiency was greater than 90% in these cells. Expression of CYP19A1 protein was detected in alveolar macrophages from wild‐type mice, but not in macrophages from Cyp19a1‐null mice, by immunohistochemical and immunofluorescence staining with an anti‐CYP19A1 antibody. Identity of macrophages was confirmed by staining with an anti‐CD14 (macrophage biomarker) antibody. The ability of macrophages in lung bronchoalveolar lavage fluid from wild‐type mice to synthesize estradiol from testosterone was demonstrated using in vitro assays and LC‐MS based detection of estradiol. The aromatase activity was not detected in macrophages from the null mice. Tissue specificity of Cyp19a1 deletion was demonstrated by the lack of detection of the null allele by a quantitative PCR analysis of genomic DNAs from multiple other sources, including lung, liver, ovary, testis, and tail. Homozygous null mice are fertile and show normal growth and activity. They are currently studied for sensitivity to the lung toxicity of naphthalene, a ubiquitous pollutant and possible human lung carcinogen.Support or Funding InformationSupported in part by NIH grant ES020867This abstract is from the Experimental Biology 2019 Meeting. There is no full text article associated with this abstract published in The FASEB Journal.