Abstract
The number of mesenchymal stem cell (MSC) therapeutic modalities has grown in recent years. Adipose-derived mesenchymal stem/stromal cells (ASCs) can be isolated and expanded relatively easily as compared with their bone-marrow counterparts, making them a particularly promising source of MSCs. And although the biological mechanisms surrounding ASCs are actively being investigated, little is known about the effects that in vivo environmental exposures might have on their ability to properly differentiate. Therefore, we hypothesized that ASCs isolated from mice exposed to inorganic arsenic (iAs) would have an altered response towards adipogenic, osteogenic, and/or chondrogenic differentiation. To test this hypothesis, C57BL/6J male mice were provided drinking water containing 0, 300, or 1000 ppb iAs. ASCs were then isolated and differentiated, which was assessed by immunocytochemistry and real-time quantitative PCR (RT-qPCR). Our results showed that total urinary arsenic equilibrated within 1 week of exposure to iAs and was maintained throughout the study. ASCs isolated from each exposure group maintained differentiation capabilities for each lineage. The magnitude of differentiation-specific gene expression, however, appeared to be concentration dependent. For osteogenesis and chondrogenesis, differentiation-specific gene expression decreased, whereas adipogenesis showed a biphasic response with an initial decrease followed by an increase in adipogenic-related gene expression following iAs exposure. These results suggest that the level in which differentiation-specific genes are induced within these stromal cells might be sensitive to environmental contaminants. These findings highlight the need to take into account potential environmental exposures prior to selecting stromal cell donors, so ASCs can achieve optimal efficiency in regenerative therapy applications.