The Immune Regulatory Mechanism of Adrenomedullin on Promoting the Proliferation and Differentiation of Dental Pulp Stem Cells

Objective: This research seeks to analyse the immunomodulatory impacts of adrenomedullin (ADM) on macrophages induced by bacterial lipopolysaccharide and to investigate the influence of macrophage-conditioned media from various stimulating factors on the biological activity of dental pulp stem cells (DPSCs) in vitro. Methods: The polarisation effect of ADM on macrophages was analysed through cell immunofluorescence staining and flow cytometry. Potential mechanisms were explored through transcriptomics and metabolomics. The impact of different macrophage-conditioned media on the biological activity of DPSCs was evaluated through western blotting, Realtime fluorescence quantitative, alkaline phosphatase activity assay, and eosin red staining. Each experiment was performed with 3 biological and 3 technical duplicate measurements. Statistical analysis was performed with t test and one-way ANOVA, and mathematical significance defined as P < .05. Results: ADM can reverse polarisation of macrophages towards M2 phenotype by Lipopolysaccharide and the conditioned media of ADM-induced M2 polarised macrophages significantly enhances the proliferation and differentiation of DPSCs. The mechanism may involve the metabolic reprogramming of macrophages by ADM, specifically promoting the metabolic shift from glycolysis to mitochondrial oxidative phosphorylation in Lipopolysaccharide-induced macrophages. Conclusion: These results indicate that ADM is involved in suppressing inflammation and enhancing the proliferation and differentiation of DPSCs by reprogramming macrophage metabolism. (c) 2024 The Authors. Published by Elsevier Inc. on behalf of FDI World Dental Federation. (http://creativecommons.org/licenses/by-nc-nd/4.0/)