Abstract
Aims:
Lipopolysaccharides (LPS) activated human dental pulp stem cells (hDPSCs) and macrophage co-cultures showed downregulated TNF-α secretion that is modulated by hDPSCs through IDO axis, whereas the secretory levels of IL-1β remained unchanged. Therefore, sustained production of IL-1β could contribute to progressive dental pulp inflammation. However, the role of IL-1 receptor antagonists (IL-1RA) in downregulating the secretion of IL-1β and TNF-α in LPS activated M0/M1/M2 macrophage and hDPSCs co-culture has not been studied yet. Therefore, the aim of the present study is to determine the immunomodulatory role of blocking IL-1 receptors in DPSCs macrophage co-culture activated with LPS.
Methodology:
Human monocytic cell line THP-1 was polarised to M0, M1, and M2 macrophages and co-cultured with hDPSCs. The viability of the co-cultured cells was assessed by apoptosis assay. Co-cultures were activated with LPS followed by the assessment of gene expression and protein levels of IL-1β and TNF-α with and without IL-1RA blocking via qRT-PCR and cytokine flex assay by flow cytometry. Data from three separate experiments was analysed using One-way ANOVA followed by Tukey's Post-hoc test and a p value of <0.05 was considered statistically significant.
Results:
THP-1 derived M0, M1, and M2 macrophages co-cultured with hDPSCs showed spindle and round-shaped cells, with > 90% viability when assessed by apoptosis assay. Inflammatory TNF-α and IL-1β profile in stimulated co-cultures showed upregulated IL-1β whereas TNF-α was downregulated (p< 0.05). Anti-inflammatory gene expression levels of IL-10, TGF-β were downregulated (p< 0.05). Blocking with IL-1RA resulted in remarkable decrease of IL-1β at the gene expression and protein production levels while TNF-α levels remained low (p< 0.05). Levels of anti-inflammatory cytokine IL-10 showed no significant difference.
Conclusion:
Blocking the IL-1 receptor in hDPSCs and macrophage (M0, M1, M2) co-cultures activated with LPS resulted in down regulation of inflammatory cytokines IL-1β and TNF-α. These findings highlight the immunomodulatory effect of IL-1RA in inflammatory conditions of dental pulp infections.
