Osteogenic potential of periodontal ligament stem cells are unaffected after exposure to lipopolysaccharides

Abstract

Periodontitis develops as a result of a continuous interaction between host cells and subgingival pathogenic bacteria. The periodontium has a limited capacity for regeneration, probably due to changes in periodontal ligament stem cells (PDLSCs) phenotype. The aim of this study was to evaluate the effects of lipopolysaccharides from Porphyromonas gingivalis (PgLPS) on mesenchymal phenotype and osteoblast/cementoblast (O/C) potential of PDLSCs. PDLSCs were assessed for Toll-like receptor 2 (TLR2) expression by immunostaining technique. After, cells were exposed to PgLPS, and the following assays were carried out: (i) cell metabolic activity using MTS; (ii) gene expression for IL-1β, TNF-α and OCT-4 by real-time polymerase chain reaction (RT-qPCR); (iii) flow cytometry for STRO-1 and CD105, and (iv) osteogenic differentiation. PDLSCs were positive for TLR2. PgLPS promoted cell proliferation, produced IL-1β and TNF-α, and did not affect the expression of stem cell markers, STRO-1, CD105 and OCT-4. Under osteogenic condition, PDLSCs exposed to PgLPS showed a similar potential to differentiate toward osteoblast/cementoblast phenotype compared to control group as revealed by mineralized matrix deposition and levels of transcripts for RUNX2, ALP and OCN. These results provide evidence that PgLPS induces pro-inflammatory cytokines, but does not change the mesenchymal phenotype and osteoblast/cementoblast differentiation potential of PDLSCs.

TLR activation inhibits the osteogenic potential of human periodontal ligament stem cells through Akt signaling in a Myd88‐ or TRIF‐dependent manner

“…Increasing evidence suggests that TLR1‒6 are expressed in human MSCs from different origins . However, reports on TLR7‒10 are inconsistent, and to date, there are few studies reporting TLR expression in hPDLSCs . In this study, we found that TLR1, TLR3, TLR4, and TLR6 are functionally expressed at high levels, whereas the expression of TLR7, ‐8, and ‐10 is very low in hPDLSCs.…”

“…17,28 However, reports on TLR7-10 are inconsistent, 6,21,25,29 and to date, there are few studies reporting TLR expression in hPDLSCs. 6,23,24 In this study, we found that TLR1, TLR3, TLR4, and TLR6 are functionally expressed at high levels, whereas the expression of TLR7, -8, and -10 is very low in hPDLSCs. However, the expression of TLR2 and TLR5 was not remarkable in hPDLSCs, which is inconsistent with a recent report.…”

“…However, there have been some inconsistent, and even controversial findings regarding to the roles of TLRs in MSC osteogenic differentiation . To date, there have been few studies that have characterized the expression of different TLRs and their effects on the osteogenic potential of hPDLSCs . Therefore, in this study, we explored the expression profile of TLRs, with emphasis on TLR1, TLR3, TLR4, and TLR6, which showed higher expression in hPDLSCs.…”

“…[19][20][21][22] To date, there have been few studies that have characterized the expression of different TLRs and their effects on the osteogenic potential of hPDLSCs. 6,23,24 Therefore, in this study, we explored the expression profile of TLRs, with emphasis on TLR1, TLR3, TLR4, and TLR6, which showed higher expression in hPDLSCs. We also studied their effects on osteogenesis in these cells and speculated on the probable mechanism associated with this process.…”

Human β-defensin 3-combined gold nanoparticles for enhancement of osteogenic differentiation of human periodontal ligament cells in inflammatory microenvironments

“…Among these receptors, TLR2 and TLR4 might be related in the progression of periodontitis. 33 In addition, LPS could increase the TNF-α activity by epithelial cells and was associated with other effects on alveolar bone loss. 34 Hence treatment with E. coli-LPS was used here to mimic the inflammatory microenvironments.…”