Transcriptional regulation of bone sialoprotein gene by Porphyromonas gingivalis lipopolysaccharide

Abstract

Lipopolysaccharide (LPS) is a major mediator of inflammatory response. Periodontopathic bacterium Porphyromonas gingivalis LPS has quite different character from Escherichia coli LPS. E. coli LPS is agonist for Toll-like receptor 4 (TLR4), whereas P. gingivalis LPS worked as antagonist for TLR4. Bone sialoprotein (BSP) is an early marker of osteoblast differentiation. To investigate the effects of P. gingivalis LPS on BSP transcription, we used rat osteoblast-like ROS17/2.8 cells. BSP mRNA levels were decreased by 0.1 microg/ml and increased by 0.01 microg/ml P. gingivalis LPS at 12 h. Results of luciferase assays showed that 0.1 microg/ml decreased and 0.01 microg/ml P. gingivalis LPS increased BSP transcription in -116 to +60 BSP construct. The effects of P. gingivalis LPS were abrogated by double mutations in cAMP response element (CRE) and FGF2 response element (FRE). Tyrosine kinase inhibitor herbimycin A, ERK1/2 inhibitor and antioxidant N-acetylcystein inhibited effects of P. gingivalis LPS. Protein kinase A inhibitor and PI3-kinase/Akt inhibitor only abolished the effect of 0.01 microg/ml P. gingivalis LPS. Furthermore, 0.1 microg/ml LPS decreased the CRE- and FRE-protein complexes formation, whereas 0.01 microg/ml P. gingivalis LPS increased the nuclear protein binding to CRE and FRE. ChIP assays revealed increased binding of CREB1, JunD, Fra2, Runx2, Dlx5, and Smad1 to a chromatin fragment containing the CRE and FRE by 0.01 microg/ml P. gingivalis LPS. These studies therefore indicated that 0.1 microg/ml suppressed, and 0.01 microg/ml P. gingivalis LPS increased BSP gene transcription mediated through CRE and FRE elements in the rat BSP gene promoter.

Lipopolysaccharide‐regulated production of bone sialoprotein and interleukin‐8 in human periodontal ligament fibroblasts: the role of toll‐like receptors 2 and 4 and the MAPK pathway

“…Therefore, the down‐regulatory effect of P. gingivalis LPS on bone sialoprotein expression might be mediated by ERK. This is similar to our previous finding , which revealed that ERK mediated the regulation of expression of the rat bone sialoprotein gene and transcription in ROS17/2.8 cells by 0.01 and 0.1 mg/mL of P. gingivalis LPS. On the other hand, the up‐regulatory effect of P. gingivalis LPS on IL‐8 expression might be mediated by p38 MAPK.…”

“…Previously, we showed that high‐dose P. gingivalis LPS decreased, whereas low‐dose P. gingivalis LPS increased, bone sialoprotein gene expression and transcription in ROS17/2.8 cells . In the current study, P. gingivalis LPS regulated bone sialoprotein mRNA levels in a similar manner in hPDLFs.…”

“…We previously reported that rat bone sialoprotein mRNA levels were decreased by 0.1 mg/L of P. gingivalis LPS and increased by 0.01 mg/L of P. gingivalis LPS, in rat osteoblast‐like ROS17/2.8 cells . To determine the molecular mechanism of P. gingivalis LPS regulation of human bone sialoprotein and IL‐8 expression, we analyzed the effects of P. gingivalis LPS on the expression of mRNA and protein of both bone sialoprotein and IL‐8 in hPDLFs .…”

Transcriptional regulation of bone sialoprotein gene by interleukin-11

“…These promoters have an inverted TATA (−24 to −19) and an inverted CCAAT box (−50 to −46), which is required for basal transcription . In addition, a cAMP response element (CRE; −75 to −68) (Samoto et al, 2003;Araki et al, 2009;Mezawa et al, 2009;Li et al, 2010;Yang et al, 2010), a fibroblast growth factor 2 (FGF2) response element (FRE; −92 to −85) (Shimizu-Sasaki et al, 2001;Samoto et al, 2003;Nakayama et al, 2006;Li et al, 2010;Wang et al, 2010;Yang et al, 2010), a runt-related transcription factor 2 (Runx2) binding site (Shimizu et al, 2006), a pituitary-specific transcription factor-1 (Pit-1) motif (−111 to −105) (Ogata et al, 2000), a homeodomain protein binding site (HOX; −199 to −192) (Benson et al, 2000;Nakayama et al, 2006;Wang et al, 2010), a transforming growth factor-β (TGF-β) activation element (−499 to −485) (Ogata et al, 1997) and a glucocorticoid response element (−920 to −906) overlapping an AP-1 site (−921 to −915) (Ogata et al, 1995;Yamauchi et al, 1996) have also been characterized.…”

Transcriptional regulation of the human bone sialoprotein gene by fibroblast growth factor 2

“…These promoters include an inverted TATA box (-24 to -19) (27) and an inverted CCAAT box (-50 to -46) (28,29). Furthermore, a CRE (-75 to -68) (12,30), a FRE (-92 to -85) (10,12,31,32), a pituitary specific transcription factor-1 (Pit-1) motif (-111 to -105) (33,34), a homeodomain protein binding site (HOX; -199 to -192) (35,36), a transforming growth factor beta (TGF-β) activation element (-499 to -485) (35,37) and a glucocorticoid response element (GRE; -920 to -906) overlapping with AP1 (-921 to -915) have been characterized (14,38).…”