Human Adipose-Derived Pericytes: Biological Characterization and Reprogramming into Induced Pluripotent Stem Cells.
BACKGROUND/AIMS
Pericytes (PCs) are multipotent vascular precursors that play a critical physiological role in the development and maintenance of blood vessel integrity. In this study, we aim to characterize PCs isolated from human abdominal adipose tissue and develop an integration-free induced pluripotent stem cells (iPSCs) using episomal vectors.


METHODS
The ultrastructure of adipose tissue-derived PCs was determined using scanning and transmission electron microscopy. The expression of mesenchymal stem cells (MSCs) and pericyte markers were examined using flow cytometry and PCR analysis. PCs were induced to adipogenic, osteogenic and myogenic lineages, and their angiogenic potential was determined using tube formation assay. We further established pericyte reprogramming protocol using episomal vectors.


RESULTS
Our data showed that human adipose tissue-derived PCs uniformly expressed MSCs, CD105 and CD73, and PCs markers, desmin, and alpha smooth muscle actin (α-SMA), while lacked the expression of HLA-DR and the hematopoietic markers CD34, CD11b and CD45. Ultrastructure analysis showed typical internal structure for the PCs with a characteristic prominent eccentric nuclei and cytoplasmic invaginations forming a caveolar system. Functional analysis showed efficient differentiation into adipocytes, osteocytes, and myocyte-like cells. Adipose tissue-derived PCs showed angiogenic potential using tube-forming assay. To determine further application of these cells for personalized therapy, we reprogrammed PCs into induced pluripotent stem cells (iPSCs) using episomal vectors. Reprogrammed cells gradually lost their fusiform shape, acquired the epithelial cell morphology and formed colonies. Furthermore, reprogrammed cells successfully expressed the pluripotency markers OCT4, Nanog, SSEA-4, and β-catenin, an early reprogramming marker.


CONCLUSION
The accessibility and abundance of human fat supports the application of adipose derived PCs as a novel and promising source of cell therapy and regenerative medicine.