Interaction of LL37, as an Antimicrobial Peptide with Bone Morphogenetic Protein 2 for Proliferation and Mineralization Ability of Cells

Objectives: An antimicrobial peptide, LL37 plays an important role in cell proliferation and odontogenic differentiation of dental pulp stem cells (DPSCs). On the other hand, Bone Morphogenetic Protein (BMP)-2 is required to complete the odontoblast maturation. However, it is unknown whether LL37 affects the BMP-2 mediated odontogenic differentiation of DPSCs. This study examined the effect of LL37 on BMP-2 induced proliferation and odontogenic differentiation of DPSCs in vitro.
Methods: For the proliferation ability, DPSCs were cultured in the basal medium (BM) or odontogenic medium (OM) containing LL37 (10 ug/ml), BMP-2 (10 ng/ml) or LL37+BMP-2. DPSC in basal medium alone was used as a control. Proliferation of cells were analyzed using WST assay after 3 and 7 days of incubation in BM and mineralization ability of cells were determined using alkaline phosphatase (ALP) and alizarin red staining (ARS) after 28 days of incubation in OM.
Results: Proliferation assay showed that there were no significant changes in the cell viability with LL37 or/and BMP-2 as compared to control at 3 days (p>0.05) while LL37 or/and BMP-2 increased the cell viability at 7 days as compared to the control group (p<0.05). ALP and ARS analysis showed that LL37 alone increased the mineralization ability of cells while its effect was lower than BMP-2 (p<0.05). LL37+BMP-2 resulted in higher ALP activity than LL37 alone (p<0.05) while ARS analysis showed that the difference between LL37 and LL37+BMP-2 in mineralized nodule formation were not statistically significant (p>0.05).
Conclusions: The findings showed that LL37 alone or in the presence of BMP-2 increased the proliferation and mineralization ability of DPSCs.