DISTINCT BIOLOGICAL RESPONSES OF MESENCHYMAL STROMAL CELLS DERIVED FROM THE HUMAN FACIAL DERMIS AND HYPODERMIS AGAINST UVA RADIATION

Abstract

<h3>Background</h3> The UVA radiation is the main environmental agent responsible for the aged aspect of the human face. Facial resident mesenchymal stromal cells play a key role in tissue homeostasis and repair, but the effects of UVA radiation in these cells are still largely unknown. In this work, we aimed to comparatively evaluate the effect of UVA radiation on the stemness characteristics and genetic integrity of human facial dermis-derived mesenchymal stromal cells and hypodermis (adipose tissue)-derived mesenchymal stromal cells (fDSCs and fASCs, respectively). <h3>Methods</h3> fDSCs and fASCs from the same donors (N=3) were submitted to a physiologically relevant dose (10 J/cm2) of UVA radiation and evaluated for their morphology, ability to generate CFU-F, proliferation, and differentiation for mesenchymal phenotypes in vitro. They were also evaluated for their genetic integrity by immunocytochemistry using anti-yH2AX, a DNA damage marker, and accumulation of reactive oxygen species by DCFH-DA assay. <h3>Results</h3> Our results demonstrated that UVA radiation reduced the capacity for self-renewal/proliferation in fASCs (12.85 times), inhibited cell differentiation, and increased the percentage of cells containing yH2AX foci in both fDSCs and fASCs (85,7% and 70% or 12.83 and 6.39 times, respectively). These effects were more severe observed in fDSCs rather than fASCs. Additionally, fDSCs showed an increase of 1.98 times in ROS levels after irradiation (P=0.0214), indicating a correlation between the loss of genetic integrity and the increase in ROS. <h3>Conclusion</h3> Our findings show that fDSCs are deeper affected by UVA radiation; however, both cell types have their stemness properties reduced upon UVA exposure. Our results may contribute to a greater understanding of human facial photoaging mechanisms and help to develop new cellular therapeutic approaches.