Vascular cell-like potential of undifferentiated ligament fibroblasts to construct vascular cell-specific marker-positive blood vessel structures in a PI3K activation-dependent manner.
OBJECTIVE
To evaluate whether fibroblasts derived from periodontal ligament retain the ability to differentiate into putative vascular cells and construct vascular cell-specific marker-positive blood vessel structures. We also evaluated the morphological features of the structure and investigated the intracellular molecular mechanism underlying the angiogenic activity of these cells.


METHODS
Single cell-derived cultures (SCDCs) were established from primary rat ligament fibroblast cultures, and their expression of ligament cell-, mesenchymal stem cell- and vascular cell-specific markers was evaluated by RT-PCR and immunocytochemistry. The ability of the cells to construct a blood vessel structure was evaluated in a three-dimensional type I collagen scaffold. The morphological and immunohistological characteristics of the structure were then evaluated.


RESULTS
Each SCDC expressed endothelial cell (EC)-specific and smooth muscle cell-specific markers, in addition to mesenchymal stem cell- and ligament cell-specific markers. SCDC2 cells, which abundantly expressed the EC markers Flk-1 and Tie-2, vigorously constructed a blood vessel structure in a phosphoinositide 3-kinase activation-dependent manner.


CONCLUSIONS
Periodontal ligament fibroblasts have the potential to construct an EC marker-positive blood vessel-like structure. Consequently, the fibroblastic lineage in ligament tissue could be a candidate precursor for construction of a vascular system around damaged ligament tissue to facilitate its regeneration.
Okubo
Naoto
N
Department of Oral Biochemistry and Molecular Biology, Division of Oral Health Science, Graduate School of Dental Medicine, Hokkaido University, West, Sapporo, Japan.
Ishisaki
Akira
A
Iizuka
Tadashi
T
Tamura
Masato
M
Kitagawa
Yoshimasa
Y
D000818:Animals; D001808:Blood Vessels / Q000254:growth & development*; D019070:Cell Lineage; D054338:Cell Transdifferentiation; D002478:Cells, Cultured; D005347:Fibroblasts / Q000166:cytology / Q000502:physiology*; D008297:Male; D059630:Mesenchymal Stem Cells / Q000502:physiology; D010513:Periodontal Ligament / Q000166:cytology*; D019869:Phosphatidylinositol 3-Kinases / Q000502:physiology; D051381:Rats; D017208:Rats, Wistar; D042787:Receptor, TIE-2 / Q000096:biosynthesis; D015398:Signal Transduction; D040301:Vascular Endothelial Growth Factor Receptor-2 / Q000096:biosynthesis
D019869:Phosphatidylinositol 3-Kinases; D042787:Receptor, TIE-2; D040301:Vascular Endothelial Growth Factor Receptor-2