Abstract P011: Endothelial Differentiation and Lineage Tracing in Adipocyte-Derived Multipotent Cells

Abstract

We previously showed that so-called de-differentiated fat (DFAT) cells, which are derived from mature white adipocytes, spontaneously differentiate into beating cardiomyocytes. Our aim in this study was to investigate if DFAT cells also differentiate into endothelial cells (ECs) in vitro, and to further examine the cellular origin of DFAT cells as well as adipose stromal cells (ASCs) using lineage tracing. First, we examined DFAT and ASCs prepared from aP2-Cre+/+;LacZ ROSA(R26R)+/+ double transgenic mice, which express LacZ under the aP2 promoter. The results revealed that 99.9% of DFAT cells and 45% of the ASCs stained positive for LacZ, supporting that the DFAT cells and part of the ASCs are of adipocytic origin. Second, we allowed newly isolated DFAT cells to spontaneously undergo EC differentiation, which was monitored by expression of EC lineage markers as determined by real-time PCR, immunofluorescence, and FACS. Expression of the EC markers CD31 and VE-cadherin increased progressively during 2 weeks in culture, the percentage of CD31(+) cells increased from 0.0% to 8.3%, and the cells formed multi-cellular tube structures when placed in Matrigel™/Collagen gels. The data supported that a fraction of the DFAT cells differentiate into ECs. Furthermore, the EC differentiation could be enhanced in DFAT cells by treatment with bone morphogenetic protein (BMP)-4 and BMP-9. In addition to EC differentiation, the DFAT cells also expressed markers of other cardiovascular lineages including smooth muscle cells and pericytes. The multipotency of DFAT cells suggests that cellular de-differentiation might be a way for differentiated cells to regain stem cell-like properties. Thus, white mature adipocytes maybe a new stem cell source for cardiovascular regeneration.