Figure 6. Cardiac Mφs induce post-MI EndMT through MT1-MMP-mediated TGFβ1 activation.

(A) Standardized MFI of LAP and TGFβ1 staining in WT and MAC-Mmp14 KO cardiac Mφs on day 7 after MI. Data are means ± SEM of 6–7 mice per group. Unpaired t-test. (B) Luciferase activity (ALU) in transfected HEK293 cells co-cultured with Mφs from 7-day-post-MI WT or MAC-Mmp14 KO hearts. Data are means ± SEM of three independent experiments performed with four technical replicates per condition. One-way ANOVA followed by Tukey's multiple comparisons test. (C) Representative immunofluorescence staining of CD31 (green) and SMA (red) in in vitro co-cultures of MAECs and cardiac Mφs from WT or MAC-Mmp14 KO 7-day-post-MI hearts. Nuclei are stained with DAPI (blue). Scale bar, 100 µm (D) CD31⁺ area (µm²) and SMA⁺ area (µm²) in the different conditions. Data are means ± SEM of a representative experiment of three performed with three technical replicates per condition. Unpaired t-test.

Figure 6—figure supplement 1. Mφs induce EndMT in vitro via MT1-MMP/TGFβ1.

(A) Representative immunofluorescence staining of CD31 (green) and SMA (red) in in vitro co-cultures of MAECs and LPS-activated WT or MAC-Mmp14 KO BMDMs. Nuclei are stained with DAPI (blue). MAECs were also treated with TGFβ1 (10 ng/mL) as an EndMT positive control. Scale bar, 100 µm (B) CD31⁺ area (µm²) and SMA⁺ area (µm²) in the different conditions. Data are means ± SEM of four independent experiments. Unpaired t-test. (C) Representative immunofluorescence staining of CD31 (green) and SMA (red) in in vitro co-cultures of MAECs and LPS-activated WT BMDMs. Nuclei are stained with DAPI (blue). MAECs were also treated with TGFβ1 (10 ng/mL) and/or neutralizing αTGFβ1 antibody (100 µg/mL). Scale bar, 100 µm (D) CD31⁺ area (µm²) and SMA⁺ area (µm²) in the different conditions. Data are means ± SEM of four independent experiments. Unpaired t-test.

Figure 6—figure supplement 2. MT1-MMP is required for in vitro Mφ induction of EndMT.

qPCR analysis of endothelial and myoFB markers and TGFβ1 target genes in in vitro co-cultures of MAECs and LPS-activated WT or MAC-Mmp14 KO BMDMs. Data are means ± SEM of a representative experiment of two performed with three technical replicates per condition. Unpaired t-test.