Conditioned medium from human adipose-derived mesenchymal stromal cells can modulate cell migration and morphology of keratinocytes in vitro

The regenerative ability of the skin is orchestrated by different types of cells, including mesenchymal stromal cells (MSCs). Their role in wound healing is being widely studied due to their capacity to produce a secretome able to modulate their microenvironment. In this context, MSCs factors can be isolated using in vitro cell culture and be experimentally tested for a series of clinical conditions, such as skin repair. In this study, we produced conditioned medium (MSC-CM) using primary cultures from human adipose-derived MSCs. This medium was used as treatment in a culture of keratinocytes cell line from adult human skin (HaCaT) to investigate the modulation of their dynamics. We analyzed cell proliferation, migration, and changes on cell morphology by labeling the actin filaments and nuclei. The factors released by MSCs were able to improve both the proliferation and migration of keratinocytes. In addition, there was an increase in the amount of actin stress fibers, filopodia protrusions, and nuclei irregularities. The MSCs secretome modified the migratory patterns of keratinocytes, being observable through their morphological changes. At least in part, this modulation was caused by the TGF-β1 signaling, considering that its antagonist, SB 431542, lead to a reduction of approximately 76% in the migration of HaCaT cells through the porous membranes of transwell chambers. Together, our data contribute to a better understanding of the role of MSCs on keratinocytes during wound healing and reinforce the importance to investigate their potential in dermal regeneration therapies.