Depletion of MSR1 in BMDMs reduced M2-like macrophages and mitochondrial OXPHOS in the co-culture system. (A) IF staining results of MSR1 WT and KO macrophages in the co-culture system for an M1-like marker (iNOS) and M2-like marker (CD206). Bar = 50 μm. (B) mRNA expression levels of M2-like marker genes (CD206 and CD163) in MSR1 WT and KO macrophages with or without co-culture by qPCR. Values are mean ± SD, *p < 0.05, ns indicates no significance. (C) Flow cytometry analysis of MSR1 WT or KO macrophages after co-culturing with BMSCs. Dot plots represent F4/80 and iNOS staining (left panel) and F4/80 and CD206 staining of macrophages (right panel). (D) Percentages of F4/80+ iNOS+ and F4/80+ CD206+ macrophages with or without co-culture were determined. Values are mean ± SD, ***p < 0.001, ns indicates no significance. (E) OCR of BMDMs in MSR1 WT or KO group after co-culture was detected using a Seahorse Bioscience XFp analyzer. O: Oligomycin, F: FCCP, A&R: antimycin A/rotenone. (F) Mitochondrial activities such as basal respiration, ATP production, respiratory capacity, and respiratory reserve were determined in indicated groups. Values are mean ± SD, *p < 0.05, **p < 0.01, ***p < 0.001, ns indicates no significance.