Comparative analysis of the potential of the secretomes of cardiac resident stromal cells and fibroblasts.

The secretome of different cell types has been applied on in vitro and in vivo assays, indicating considerable therapeutic potential. However, the choice of the ideal cell type and culture conditions for obtaining the best set of soluble factors, as well as the assays to assess specific effects, remain subjects of vigorous debate. In this study, we used mass spectrometry to characterize the secretomes of ventricle derived-cardiac resident stromal cells (vCRSC) and human dermal fibroblasts (HDFs) and evaluate them in an effort to understand the niche specificity of biological responses toward different cellular behaviors, such as cell proliferation, adhesion, migration, and differentiation. It was interesting to note that the HDF and vCRSC secretomes were both able to induce proliferation and cardiac differentiation of H9c2 cells, as well as to increase the adhesion activity of H9c2 cells and human umbilical vein endothelial cells. Analysis of the secretome composition showed that the vCRSCs derived from different donors secreted a similar set of proteins. Despite the differences, almost half of the proteins identified in conditioned medium were common to both HDF and vCRSC. Consequently, a high number of common biological processes were identified in the secretomes of the two cell types, which could help to explain the similar results observed in the in vitro assays. We show that soluble factors secreted by both HDF and vCRSC are able to promote proliferation and differentiation of cardiomyoblasts in vitro. Our study indicates the possible use of vCRSC or HDF secretomes in acellular therapies for regenerative medicine.