Neuropilin Controls Endothelial Differentiation by Mesenchymal Stem Cells From the Periodontal Ligament

Periodontal ligament (PDL) has been reported to be a source of mesenchymal stem cells (MSCs).New vascular networks from undifferentiated cells are essential for repair/regeneration of specialized tissues, including PDL. The current study aims to determine potential of CD105(+)-enriched cell subsets of periodontal ligament cells (PDLSCs) to differentiate into endothelial cell (EC)-like cells and to give insights into the mechanism involved.

CD105(+)-enriched PDLSCs were induced to EC differentiation by endothelial growth medium 2 (EGM-2) for 3, 7, 14, and 21 days, with mRNA/protein levels and functional activity assessed by: 1) real-time polymerase chain reaction; 2) Western blotting; 3) fluorescence-activated cell sorting; 4) immunohistochemistry; 5) immunofluorescence; 6) matrigel; and 7) small interfering RNA assays.

Data analyses demonstrated that EGM-2 treated PDLSCs presented increased expression of EC markers, including: 1) CD105; 2) kinase domain-containing receptor; and 3) Ulex europaeus agglutinin 1, and were able to form cord/tube-like structures. Gene and protein expression analysis showed that neuropilin 2 (NRP2), a key factor for vascular development, was significantly downregulated during EC differentiation. NRP2 was constitutively expressed in mouse PDL tissues by immunohistochemistry analysis, and NRP2 knockdown in CD105(+)-enriched PDLSCs resulted in increased cord/tube-like structures in a matrigel assay.

These findings demonstrated the potential of CD105(+)-enriched PDLSCs to support angiogenesis, and NRP2 as a pivotal factor regulating this process.