Presenting Author University of Nebraska Medical Center, Nebraska
The cardiac fibroblast is the key cell type regulating scar formation after myocardial infarction (MI). Whether the fibroblast also serves a role in the early pro-inflammatory phase has not been evaluated. For this study we evaluated secretome from no MI day (D) 0 and MI D1 cardiac fibroblast to understand the roles of D1 fibroblast in cellular communication during the pro-inflammatory phase of MI wound healing. Cardiac fibroblasts were isolated from day (D) 0 (n=3) left ventricle and MI D1 (n=3) infarct region, and the 24 h secretome was collected from passage 2 cells. We used mass spectrometry to catalogue and quantify the secretome. We identified galectin-1 as a highly upregulated D1 MI secreted factor. Because galectin-1 is known in other systems to be anti-inflammatory, we stimulated bone marrow derived macrophages (1.5x106 cells/ well; n=8 4M/4F paired sets) with galectin-1 (500 ng/ml) in the presence of interleukin (IL)-1b (200 ng/ml) or IL-10 (50 ng/ml). The conditioned media was assayed using proteome profiler mouse XL cytokine array (RnD) and immunoblotting validation. We also used a human glycosylation array 1000 (RayBio) to evaluate plasma from healthy controls (n=18) and patients 48h after MI (n=41). Galectin-1 was 3-fold elevated in the MI D1 secretome (p=0.007). Galectin-1 increased IL-10 release (p=0.02) in the macrophages treated wtih IL-10, a finding validated by two methods. In humans, Galectin-1 was 2.2-fold increased at 48h after MI compared to healthy controls (p=0.013). In conclusion, the fibroblast secretes galectin-1 to modulate the macrophage response after MI by stimulating anti-inflammatory macrophage polarization and potentially improve MI wound healing.
