Sugarcane cystatin CaneCPI‐1 promotes osteogenic differentiation in human dental pulp cells: a new insight into cysteine proteases inhibitors.

Aim: To investigate the biocompatibility, type of cell death, osteogenic bioactivity and mRNA expression of the osteogenic markers, induced by CaneCPI‐1 in human dental pulp cells (hDPCs). Methodology: hDPCs exposed to CaneCPI‐1 and not exposed (control) were evaluated for cell viability by the 3‐(4,5‐dimethylthiazol)‐2,5‐diphenyltetrazolium bromide (MTT) assay; apoptosis by flow cytometry; alkaline phosphatase (ALP) activity by calculation of thymolphthalein release; gene expression of bone morphogenetic protein 2 (BMP‐2), runt‐related transcription factor 2 (RUNX2), ALP, osteocalcin (OC), bone sialoprotein (BSP) by qPCR; and mineralized nodules production by using alizarin red staining. The data were analysed by one‐way analysis of variance (anova) and Turkey's post‐test, two‐way anova and Bonferroni post‐test or t‐test (P < 0.05). Results: CaneCPI‐1 induced no apoptosis and had no cytotoxic effect, except in the concentration of 33.20 µm, in which cell viability was significantly lower than the control (α‐MEM nonosteogenic medium serum‐free) (P < 0.05). There was significantly greater ALP activity, greater expression of the BMP‐2, RUNX2, ALP, OC and BSP genes and greater mineralized nodules production in the CaneCPI‐1 group in comparison with the control or osteogenic α‐MEM control (α‐MEM osteogenic medium – L‐ascorbic acid and β‐glycerophosphate) (P < 0.05). Conclusions: CaneCPI‐1 was cytocompatible and also induced the differentiation of hDPCs in osteogenic phenotype in vitro. CaneCPI‐1 is a promising molecule to induce pulp repair. [ABSTRACT FROM AUTHOR]