Modulation of Prickle2 Expression to Facilitate Dentine Formation: A Laboratory Investigation.

Aim: Prickle planar cell polarity (PCP) protein 2 (Prickle2) encodes a homologue of Drosophila prickle and is involved in the non-canonical Wnt/PCP signalling pathway. However, its exact role in dentinogenesis remains unclear. Dentinogenesis, a key process in tooth morphogenesis, involves the patterned arrangement of odontoblasts and the formation of dentine matrix along the pulp cavity. This study investigates the role of PCP signalling, particularly Prickle2, in odontogenesis and dentine formation. Additionally, this study evaluates the potential application of Prickle2 modulation for dentine regeneration using an animal experimental model.

Methodology: The developmental function of Prickle2 in tooth morphogenesis was examined by analysing its precise expression pattern in the primary enamel knot. Gain and loss of function studies were performed using in vitro organ cultivation and renal capsule transplantation. At embryonic day 13 (E13), Prickle2 was knocked down using small interfering ribonucleic acid (siRNA) treatment, and histogenesis, cellular physiology (proliferation and apoptosis), and the expression of PCP pathway-related genes and tooth-related signalling molecules were examined. Furthermore, renal capsule transplantation was conducted for 3 weeks to analyse the morphological changes in tooth crown formation. To evaluate the clinical applicability of Prickle2 modulation in dentine regeneration, a pulp exposure animal model was employed, locally administering siRNA against Prickle2 into the exposed pulp cavity of the maxillary first molar at week 8 for 6 weeks.

Results: At E13.5, in situ hybridization revealed the distinctive expression of Prickle2 in the enamel knot area. Knockdown of Prickle2 at E13 led to significant alterations in histogenesis and changes in key signalling molecule expression. Renal capsule transplantation resulted in morphological changes, including a thicker pre-dentine layer and the formation of a more opaque crown. In the pulp exposure model, siRNA treatment facilitated the formation of a dentinal bridge compared to controls.

Conclusion: Our findings suggest that Prickle2 regulates dentinogenesis through Wnt/PCP signalling. Modulating Prickle2 expression presents a promising approach for dentine regeneration.