Extracts of Prevotella intermedia and Actinobacillus actinomycetemcomitans inhibit alkaline phosphatase activity in osteoblastic cells in vitro

Abstract

In order to study the effects of sonicated extracts from Prevotella intermedia, Actinobacillus actinomycetemcomit‐ans, Porphyromonas gingivalis, and other oral‐related bacteria, as well as Escherichia coli on bone formation, clone MC3T3‐E1 cells, which have retained osteoblastic activity, were cultured with various bacterial extracts. The addition of the sonicated extracts from Prevotella intermedia and Actinobacillus actinomycetemcomitans decreased the alkaline phosphatase activity in a dose‐dependent fashion over the concentration range of 1– 1000 ng ml‐1 compared with the control. By contrast, the sonicated extracts from other oral bacteria including Porphyromonas gingivalis, Capnocytophaga ochracea, Streptococcus milleri and Streptococcus sanguis, and Escherichia coli did not decrease the alkaline phosphatase activity even in the presence of 100 ng ml‐1 protein. The addition of Prevotella intermedia and Actinobacillus actinomycetemcomitans extracts that had been treated with heat and trypsin to the cell cultures also inhibited alkaline phosphatase activity in the cells, suggesting that inhibitory factors are not proteinaceouS. Polymyxin B did not change the alkaline phosphatase activity in the cells treated with the extracts from Prevotella intermedia and Actinobacillus actinomycetemcomitans, suggesting that the inhibitory activity of the extracts is not lipopolysaccha‐ride. The inhibitory effect of both extracts was observed in the molecular mass over 290 kDa eluted from Sephadex G‐200 column. The inhibitory substances of Prevotella intermedia were partially purified and showed broad band with estimated molecular weight of 170–190 kDa by sodium dodecyl sulfate‐polyacrylamide gel electro‐phoresis. These results indicate that Prevotella intermedia and Actinobacillus actinomycetemcomitans may play an important role in inhibiting bone formation as well as in stimulating bone resorption.

Prolonged exposure to bacterial toxins downregulated expression of toll-like receptors in mesenchymal stromal cell-derived osteoprogenitors

“…Documented effects of E. coli LPS on osteoblastic cells are mixed. No inhibitory effect of E. coli LPS were found on osteoblastic cell line MC3T3-E1 and rat calvaria cells [ 17 , 39 ]. However, Shjoi et al found an inhibitory effect on ALP activity of SaOS-2, an osteoblast-like osteosarcoma cell line [ 15 ].…”

Lipopolysaccharide alters decorin and biglycan synthesis in rat alveolar bone osteoblasts: consequences for bone repair during periodontal disease

“…These results do contradict the results of studies published previously. For instance, sonicated extracts of P. gingivalis had no effect on the alkaline phosphatase activity of MC3T3‐E1, a pre‐osteoblast‐like cell line (43); and P. gingivalis LPS had no effect on the cell number (as determined by DNA content) of cultures derived from the periosteum of calvarial bone (33). These contradictions may reflect different biological responses relative to the source and progenitor status of the cells analysed.…”

“…The source and preparation of the pathogenic agent should also be considered in regard to the diversity of the published findings. Different cellular responses regarding the alkaline phosphatase activity of MC3T3‐E1 cells have been reported for sonicated extracts of P. gingivalis , P. intermedia , and Aggregatibacter (Actinobacillus) actinomycetemcomitans (43). Likewise, P. intermedia and A. actinomycetemcomitans produce different apoptopic responses on osteoblast‐like cell lines, including MG63 (45).…”

Periodontopathogen and Epstein‐Barr Virus Contamination Affects Transplanted Bone Volume in Sinus Augmentation

“…The capability to hinder osteogenesis seems to be a pathogenic trait restricted to a distinct group of species. Gram‐negative anaerobic rods associated with destructive periodontal disease have exhibited a collection of virulence factors that directly impair osteogenesis and induce bone loss 17‐21 . Prevotella intermedia (Pi) can inhibit osteoblast alkaline phosphatase activity and negatively affect bone formation 20 .…”