Fig. 4.

Inflammatory crosstalk between aged TIMD4^– macrophages and fibroblasts implies the macrophage MR and superoxide production in the mitochondria. A Experimental outline. Cardiac TIMD4⁺ and TIMD4^– macrophages and fibroblasts were isolated from hearts of young MR^flox mice (Young) or from hearts of old MR^flox and MR^LysMCre mice (Aging). Macrophage subpopulations were co-cultured with fibroblasts for 3 days. For MitoTEMPO experiments TIMD4^– macrophages from aging MR^flox hearts were incubated in the presence of MitoTEMPO overnight before co-culture with fibroblasts. B IL-6, C CCL2, D IL-1ß, and E pro-collagen I alpha 1 levels in the conditioned medium of cardiac fibroblasts cultured alone or co-cultured for 3 days with TIMD4⁺ and TIMD4^– macrophages. F Mitochondrial O₂^·− production by TIMD4⁺ and TIMD4^– macrophages cultured in the presence of fibroblasts assessed using a highly sensitive isocratic ion-pair HPLC-EC method. The treatment with the mitochondrial reactive oxygen species scavenger MitoTEMPO prevented the production of O2^·− by TIMD4^– macrophages cultured in the presence of fibroblasts, and secretion of inflammatory cytokines in the co-culture medium of TIMD4^– macrophages and fibroblasts isolated from old MR^flox hearts. Mean ± SEM, n = 3–10 per group; *p < 0.05