Porphyromonas gingivalis lipopolysaccharides affect gingival stem/progenitor cells attributes through NF-κB, but not Wnt/β-catenin pathway

Aim The present study investigates for the first time the effect of Porphyromonas gingivalis lipopolysaccharides (Pg-LPS) on proliferative/regenerative aptitudes of gingival stem/progenitor cells (G-MSCs). Material and Methods G-MSCs (n=5) were treated by 0, 10ng/ml, 100ng/ml, 1μg/ml or 10μg/ml Pg-LPS. At 1 hour, toll like receptor 4 (TLR-4) expression, NF-κB and Wnt/β-catenin signalling pathways were examined. Colony forming unit assay was conducted at 12 days. At 24 and 48 hours, MTT test, ALP activity, mRNA for Tumor necrosis factor α (TNF-α), Interleukin-6, Collagen-I (Col-I), Collagen-III, RUNX-2, Alkaline phosphatase (ALP), Osteonectin and protein expression of Interleukin-6 and TNF-α were analysed. Results With increasing Pg-LPS, TLR-4 was upregulated, pNF-κB-p65 rose from median (Q25/Q75) 6.56%(4.19/7.90) to 13.02%(8.90/16.50;p=0.002) and pNF-κB-p65/tNF-κB-p65 from 0.14(0.10/0.17) to 0.30(0.21/0.42;p=0.002). pβ-catenin, tβ-catenin and pβ-catenin/tβ-catenin showed no differences. Increasing Pg-LPS-concentration, increased cell numbers from 288.00(72.98/484.32) to 861.39(540.41/1599.94;p=0.002), ALP mRNA from 0.00(0.00/0.01) to 0.56(0.00/1.90;p=0.004) and TNF-α from 32.47(12.11/38.57) to 45.32(28.68/48.65;p=0.036). Over time, ALP activity increased from 0.89(0.78/0.95) to 1.90(1.83/2.09;p<0.001), mRNA for TNF-α from 0.00(0.00/0.12) to 0.01(0.00/0.06;p=0.007), mRNA for Col-I from 82.70(0.03/171.50) to 124.00(52.85/232.50;p=0.019), while mRNA for RUNX-2 decreased from 1.73(0.92/3.20) to 0.84(0.48/1.47;p=0.005). Conclusions Pg-LPS upregulated G-MSCs’ proliferation, without attenuation of their regenerative potential. The effects were NF-κB, but not Wnt/β-catenin pathway dependent. This article is protected by copyright. All rights reserved.