Effects of Porphyromonas gingivalis lipopolysaccharide on the behavior of human dental pulp stem cells in vitro and their inflammation-related transcriptomics profile

Objective

The inflammatory microenvironment in pulpitis and periapical periodontitis critically impairs dental pulp stem cells (DPSCs) functionality, yet the underlying molecular mechanisms remain poorly defined. This study aimed to investigate the effects of Porphyromonas gingivalis lipopolysaccharide (P. gingivalis LPS) on human DPSCs behavior and elucidate the transcriptomic changes underlying LPS-induced inflammation.

Design

Human DPSCs were exposed to 1 µg/mL LPS for 24 hours to establish an inflammatory model, with subsequent evaluation of proliferation (CCK-8), migration (Transwell), and odontogenic differentiation (ALP staining, mineralization assays and odontoblast markers expression). Cell cycle progression was quantified through flow cytometry, while RNA sequencing analysis delineated transcriptional alterations.

Results

LPS exposure significantly attenuated DPSCs proliferative capacity (P < 0.01), suppressed migration (P < 0.01), and impaired odontogenic differentiation, evidenced by diminished ALP activity, mineralized nodule formation and odontoblast markers expression. Cell cycle analysis revealed G0/G1 phase arrest (P < 0.01), indicating proliferative quiescence. Transcriptomic profiling identified 467 differentially expressed genes. P. gingivalis LPS exerts its effects on DPSCs by concurrent activation of both canonical (Toll-like receptors, TLRs) and non-canonical (Nucleotide-binding oligomerization domain-like receptor) signaling pathway. Pathway enrichment revealed the enrichment of the several important signaling pathways such as Phosphatidylinositol 3 kinase-protein kinase B (PI3K-Akt), tumor necrosis factor (TNF) /Nuclear factor kappa B (NF-κB) and interleukin (IL) −17 signaling under LPS stimulation.

Conclusion

P. gingivalis LPS disrupts DPSCs regenerative functions by modulating inflammatory and developmental signaling pathways, providing mechanistic insights into impaired pulp repair during oral infections.