Macrophage PAR2 is dispensable for steady-state postnatal erythropoiesis. (A) Brains were collected from adult WT and PAR2^−/− mice, and mRNA gene expression was analyzed for myeloid populations in brain (Aif1, Csfr1, Trem2) or for more specific microglia markers (Hexb, P2ry12, Tmem-119). (B) Peripheral blood from 11- to 12-week-old adult male and female PAR2^flfl-LysMcre mice and PAR2^flfl littermate control mice was collected for differential blood counting. (C) Representative fluorescence-activated cell sorting plots, gating strategy following gating on single cells, and quantification of different WBC populations in the bone marrow from 8- to 10-week-old adult male and female PAR2^flfl-LysMcre mice and PAR2^flfl littermate control mice. Most macrophages in the bone marrow are F480⁺/CD115⁻/VCAM1⁺. Using 2-way ANOVA, there was no significant differences between genotypes. (D) RBC counts, hematocrit (HCT), mean corpuscular volume (MCV), and hemoglobin levels (HGB) in male and female PAR2^flfl-LysMcre mice and PAR2^flfl littermate control mice challenged at days 0 and 1 with phenylhydrazine (50 mg/kg body weight). HGB levels were not analyzed at day 3 because of interference with the injected phenylhydrazine. *P < .05, unpaired Student t test.