R-Loops Mediated Odontogenic Differentiation of hDPSCs by Activating the cGAS-STING Pathway Under Inflammatory Microenvironment.

BACKGROUND

R-Loops are three-stranded DNA/RNA hybrids implicated in immune responses. Their role in mesenchymal stem cell differentiation, particularly in dental pulp regeneration under inflammation, remains unclear.

METHODS

Rat pulpo-dentinal complex (PDC) injury models and LPS-stimulated human dental pulp stem cells (hDPSCs) were used. R-Loops and cGAS-STING were evaluated via immunofluorescence, immunohistochemistry, RNA-seq, RT-qPCR, ALP, and Alizarin Red S staining. Interventions included RNase H1 overexpression (to degrade R-Loops) and STING inhibitor H151.

RESULTS

Inflammation induced R-Loops accumulation and cGAS-STING activation in vivo and in vitro, correlating with impaired odontogenic differentiation. RNase H1 or H151 treatment downregulated inflammatory cytokines (IFN β, IL 6, TNF α) and restored mineralization capacity of hDPSCs.

CONCLUSION

R-Loops promote inflammation and suppress odontogenesis via cGAS-STING signaling. Targeting this axis alleviates inflammation and enhances regenerative potential, offering a therapeutic strategy for pulpitis.