Establishment of immortalized periodontal ligament progenitor cell line and its behavioural analysis on smooth and rough titanium surface.

Periodontal ligament (PDL) can be obtained from patients undergoing orthodontic treatment. PDL contains progenitor cells that can be expanded and differentiated towards several mesenchymal lineages in vitro. Furthermore, PDL-derived cells have been shown to generate bone- and PDL-like structures in vivo. Thus, PDL cells, combined with suitable biomaterials, represent a promising tool for periodontitis-related research and PDL engineering. Here, a new PDL cell line using lentiviral gene transfer of human telomerase reverse transcriptase (hTERT) was created. HTERT-expressing PDL cells showed similar morphology and population doubling time but an extended lifespan compared to the primary cells. In addition, PDL-hTERT cells expressed several characteristic genes and upon osteogenic stimulation produced a calcified matrix in vitro. When cultivated on two topographically different titanium scaffolds (MA and SLA), PDL-hTERT cells exhibited augmented spreading, survival and differentiation on smooth (MA) compared to rough (SLA) surfaces. These findings differ from previously reported osteoblast behaviour, but they are in agreement with the behaviour of chondrocytes and gingival fibroblasts, suggesting a very cell type-specific response to different surface textures. In summary, we report the testing of titanium biomaterials using a new PDL-hTERT cell line and propose this cell line as a useful model system for periodontitis research and development of novel strategies for PDL engineering.