Origin of dedifferentiated adipocyte-derived cells (DFAT) during ceiling culture in an Adiponectin Cre-Recombinase mouse model.

DFAT cells represent an attractive source of stem cells in tissue engineering and in the potential treatment of several clinical conditions. Our objective was to determine whether DFAT cells originate from mature adipocytes and address whether contamination from the stromal vascular fraction (SVF) could be as a source for these cells. A murine adiponectin-creERT;mT/mG model was used with the excision of the cassette induced by tamoxifen injection for the cells expressing adiponectin (adipoq). This model allows distinguishing of mature adipocytes (green fluorescence) from other SVF cell types (red fluorescence) based on the fluorescent protein expressed. Mature adipocytes and SVF cells were isolated from adipose tissues by collagenase digestion. Ceiling cultures were imaged by time-lapse microscopy. Confocal microscopy was used to follow cells over 21 days. Time-lapse microscopy experiments showed liposecretion occurring in mature adipocytes displaying green fluorescence. Confocal imaging allowed the identification of a heterogeneous cell population expressing green but also red fluorescence after 21 days of culture. Asymmetrical division of mature adipocytes was not observed. In conclusion, liposecretion of mature adipocytes is a phenomenon that can be observed in vitro and DFAT cells do originate from mature adipocytes However, the population of DFAT cells is heterogenous.