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

AimThis 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 MethodsG-MSCs (n=5) were treated by 0, 10ng/ml, 100ng/ml, 1g/ml or 10g/ml Pg-LPS. At 1hour, Toll-like receptor 4 (TLR-4) expression and NF-B and Wnt/-catenin signalling pathways were examined. Colony-forming unit assay was conducted at day 12. At 24 and 48hours, MTT test, ALP activity, mRNA for tumour necrosis factor- (TNF-), interleukin-6, collagen-I (Col-I), collagen-III, RUNX-2, alkaline phosphatase (ALP), osteonectin and protein expression of interleukin-6 and TNF- were analysed. ResultsWith increasing Pg-LPS, TLR-4 was upregulated, pNF-B-p65 rose from median (Q25/Q75) 6.56% (4.19/7.90) to 13.02% (8.90/16.50; p=0.002) and pNF-B-p65/tNF-B-p65 from 0.14(0.10/0.17) to 0.30(0.21/0.42; p=0.002). p-Catenin, t-catenin and p-catenin/t-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- 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- 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). ConclusionsPg-LPS upregulated G-MSCs' proliferation, without attenuation of their regenerative potential. The effects were NF-B, but not Wnt/-catenin, pathway dependent.