SCH-772984

The study examined the induction and mechanism of bone regeneration facilitated by the P24‐loaded Gelatin‐Hydroxyapatite‐Tricalcium Phosphate (Gelatin‐HA‐TCP (P24)) scaffold. The prepared Gelatin‐HA‐TCP (P24) scaffold was employed to treat human bone marrow mesenchymal stem cells (hBMSCs) and human umbilical vein endothelial cells (HUVECs). Various assays were conducted to assess the impact of the Gelatin‐HA‐TCP (P24) scaffold on the osteogenic differentiation of hBMSCs and angiogenesis in HUVECs. For mechanistic investigations, hBMSCs were exposed to both the Gelatin‐HA‐TCP (P24) scaffold and the ERK inhibitor SCH772984. A rat cranial bone defect model was treated through the implantation of the Gelatin‐HA‐TCP (P24) scaffold. Micro‐computed tomography, histological staining, and immunofluorescence techniques were utilized to evaluate the effect of the Gelatin‐HA‐TCP (P24) scaffold on cranial bone regeneration. Osteogenic differentiation of hBMSCs was facilitated by the Gelatin‐HA‐TCP (P24) scaffold, as evidenced by increased ALP activity, enhanced Alizarin Red S staining, and upregulated RUNX2, OSX, OCN, and BMP2. Angiogenesis in HUVECs was induced, as demonstrated by improved migration, tube formation, and upregulated CD31. However, the ability of the Gelatin‐HA‐TCP (P24) scaffold to promote osteogenic differentiation in hBMSCs was counteracted by SCH772984. In the rat cranial bone defect model, implantation of the Gelatin‐HA‐TCP (P24) scaffold reduced the bone defect area, increased the bone volume/tissue volume ratio, enhanced bone regeneration, decreased bone fibrosis, and upregulated CD31, RUNX2, and BMP2 in bone tissues. Therefore, the Gelatin‐HA‐TCP (P24) scaffold enhances the osteogenic differentiation of hBMSCs and promotes bone regeneration in cranial bone defects by activating the ERK/ELK1/PLA2G3 pathway. It has potential for bone regeneration therapies.

The multipotency of dental pulp stem cells (DPSCs) plays a crucial role in dental tissue regeneration, yet its regulatory mechanisms remain incompletely understood. This study aimed to investigate the role of natriuretic peptide receptor 3 (NPR3) in regulating DPSCs functions and validate the mechanism of its targeted inhibitor ligustrazine (TMP).

NPR3 expression in DPSCs was examined by Western blot and immunohistochemistry. The effects of NPR3 on DPSCs colony formation, migration, and differentiation were investigated through overexpression and knockdown strategies. The relationship between NPR3 and ERK1/2 pathway was explored using molecular biological approaches. High-throughput drug screening was employed to identify TMP as an NPR3 inhibitor, followed by mechanism validation.

NPR3 was highly expressed in mature odontogenic DPCs, with its expression levels closely correlated with DPSCs functions. Functional assays demonstrated that NPR3 inhibited DPSCs colony formation, migration, and differentiation capabilities, while NPR3 knockdown significantly enhanced these functions. Mechanistic studies revealed that NPR3 influenced DPSCs functions through positive regulation of ERK1/2 phosphorylation. Through high-throughput screening, we identified TMP as a specific NPR3 inhibitor that promoted DPSCs functions. Rescue experiments further confirmed that NPR3 overexpression or ERK1/2 inhibitor SCH772984 attenuated TMP-induced enhancement, validating TMP's action through the NPR3/MAPK pathway.

This study reveals the crucial role of the NPR3/MAPK pathway in regulating DPSCs multipotency and demonstrates that TMP enhances DPSCs functions through targeted inhibition of this pathway, providing new therapeutic strategies and drug targets for dental tissue regeneration.