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Pro-atherogenic lung and oral pathogens induce an inflammatory response in human and mouse mast cells.

Oksaharju A, Lappalainen J, Tuomainen AM, Pussinen PJ, Puolakkainen M, Kovanen PT, Lindstedt KA - J. Cell. Mol. Med. (2009)

Bottom Line: Human monocyte-derived macrophages that were pre-infected with Cpn also induced a significant pro-inflammatory response in human mast cells, both in cocultures and when preconditioned media from Cpn-infected macrophages were used.Intranasal and intravenous administration of live Cpn and Aa, respectively induced an accumulation of activated mast cells in the aortic sinus of apolipoprotein E-deficient mice, however, with varying responses in the systemic levels of lipopolysaccharide (LPS) and TNF-alpha.Pro-atherogenic Cpn and Aa induce a pro-inflammatory response in cultured human connective tissue-type mast cells and activation of mouse aortic mast cells in vivo.

View Article: PubMed Central - PubMed

Affiliation: Wihuri Research Institute, Kalliolinantie, Helsinki, Finland.

ABSTRACT
A broad variety of microbes are present in atherosclerotic plaques and chronic bacterial infection increases the risk of atherosclerosis by mechanisms that have remained vague. One possible mechanism is that bacteria or bacterial products activate plaque mast cells that are known to participate in the pathogenesis of atherosclerosis. Here, we show by real-time PCR analysis and ELISA that Chlamydia pneumoniae (Cpn) and a periodontal pathogen, Aggregatibacter actinomycetemcomitans (Aa), both induce a time and concentration-dependent expression and secretion of interleukin 8 (IL-8), tumour necrosis factor-alpha (TNF-alpha) and monocyte chemoattractant protein-1 (MCP-1) by cultured human peripheral blood-derived mast cells, but not anti-inflammatory molecules, such as IL-10 or transforming growth factor beta 1 (TGF-beta 1). The IL-8 and MCP-1 responses were immediate, whereas the onset of TNF-alpha secretion was delayed. The Cpn-mediated pro-inflammatory effect was attenuated when the bacteria were inactivated by UV-treatment. Human monocyte-derived macrophages that were pre-infected with Cpn also induced a significant pro-inflammatory response in human mast cells, both in cocultures and when preconditioned media from Cpn-infected macrophages were used. Intranasal and intravenous administration of live Cpn and Aa, respectively induced an accumulation of activated mast cells in the aortic sinus of apolipoprotein E-deficient mice, however, with varying responses in the systemic levels of lipopolysaccharide (LPS) and TNF-alpha. Pro-atherogenic Cpn and Aa induce a pro-inflammatory response in cultured human connective tissue-type mast cells and activation of mouse aortic mast cells in vivo.

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Effect of bacterial infectivity on mast cell cytokine expression. Cpn and 2 strains (AT445b and JP2) of Aa were treated with UV-light (2 × dosage of 0.120 J/cm2). Cultured human mast cells were inoculated with UV-treated or untreated bacteria in a cell-to-bacteria ratio of 1: 10 for 6 hrs. Quantitative analysis of IL-8 (A), TNF-α (B) and MCP-1 (C) mRNA expression was performed with real-time PCR and the concentrations of these cytokines in the incubation media were detected by ELISA (IL-8 [D]), TNF-a [E] and MCP-1 [F]). Data are means ± SD and the results shown are representative of three independent experiments.
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fig04: Effect of bacterial infectivity on mast cell cytokine expression. Cpn and 2 strains (AT445b and JP2) of Aa were treated with UV-light (2 × dosage of 0.120 J/cm2). Cultured human mast cells were inoculated with UV-treated or untreated bacteria in a cell-to-bacteria ratio of 1: 10 for 6 hrs. Quantitative analysis of IL-8 (A), TNF-α (B) and MCP-1 (C) mRNA expression was performed with real-time PCR and the concentrations of these cytokines in the incubation media were detected by ELISA (IL-8 [D]), TNF-a [E] and MCP-1 [F]). Data are means ± SD and the results shown are representative of three independent experiments.

Mentions: To estimate the concentration of bacteria required to trigger cytokine release by human mast cells in culture, increasing amounts of bacteria were used to inoculate the cells. Mast cells cocultured with Cpn in a 1: 1 cell-to-bacterium ratio already induced a significant expression of TNF-α (P= 0.049), IL-8 (P= 0.020) and MCP-1 (P= 0.035) mRNA, and the corresponding ratios of 1: 5 and 1: 10 still further increased the expression levels of the investigated genes (Fig. 3). To test whether the induction of cytokine mRNA expression and protein secretion by mast cells was dependent on the viability of the bacteria, the pathogens were treated with UV radiation before inoculation, as described in Materials and Methods. Indeed, UV treatment of Cpn inhibited the induction of IL-8, both at the mRNA (P= 0.002) and protein (P= 0.0015) level, revealing that the IL-8 response was dependent on the viability of the bacteria. Similarly, both the synthesis and secretion of TNF-α were significantly reduced (P= 0.017 and P= 0.0001, respectively) when the mast cells were inoculated with UV-treated Cpn, as compared to live bacteria (Fig. 4). In contrast, inactivation of Cpn failed to reduce the expression and secretion of MCP-1. Finally, UV-treatment of either strain of Aa had only minor effects on the expression and secretion of cytokines (Fig. 4).


Pro-atherogenic lung and oral pathogens induce an inflammatory response in human and mouse mast cells.

Oksaharju A, Lappalainen J, Tuomainen AM, Pussinen PJ, Puolakkainen M, Kovanen PT, Lindstedt KA - J. Cell. Mol. Med. (2009)

Effect of bacterial infectivity on mast cell cytokine expression. Cpn and 2 strains (AT445b and JP2) of Aa were treated with UV-light (2 × dosage of 0.120 J/cm2). Cultured human mast cells were inoculated with UV-treated or untreated bacteria in a cell-to-bacteria ratio of 1: 10 for 6 hrs. Quantitative analysis of IL-8 (A), TNF-α (B) and MCP-1 (C) mRNA expression was performed with real-time PCR and the concentrations of these cytokines in the incubation media were detected by ELISA (IL-8 [D]), TNF-a [E] and MCP-1 [F]). Data are means ± SD and the results shown are representative of three independent experiments.
© Copyright Policy
Related In: Results  -  Collection

Show All Figures
getmorefigures.php?uid=PMC3823039&req=5

fig04: Effect of bacterial infectivity on mast cell cytokine expression. Cpn and 2 strains (AT445b and JP2) of Aa were treated with UV-light (2 × dosage of 0.120 J/cm2). Cultured human mast cells were inoculated with UV-treated or untreated bacteria in a cell-to-bacteria ratio of 1: 10 for 6 hrs. Quantitative analysis of IL-8 (A), TNF-α (B) and MCP-1 (C) mRNA expression was performed with real-time PCR and the concentrations of these cytokines in the incubation media were detected by ELISA (IL-8 [D]), TNF-a [E] and MCP-1 [F]). Data are means ± SD and the results shown are representative of three independent experiments.
Mentions: To estimate the concentration of bacteria required to trigger cytokine release by human mast cells in culture, increasing amounts of bacteria were used to inoculate the cells. Mast cells cocultured with Cpn in a 1: 1 cell-to-bacterium ratio already induced a significant expression of TNF-α (P= 0.049), IL-8 (P= 0.020) and MCP-1 (P= 0.035) mRNA, and the corresponding ratios of 1: 5 and 1: 10 still further increased the expression levels of the investigated genes (Fig. 3). To test whether the induction of cytokine mRNA expression and protein secretion by mast cells was dependent on the viability of the bacteria, the pathogens were treated with UV radiation before inoculation, as described in Materials and Methods. Indeed, UV treatment of Cpn inhibited the induction of IL-8, both at the mRNA (P= 0.002) and protein (P= 0.0015) level, revealing that the IL-8 response was dependent on the viability of the bacteria. Similarly, both the synthesis and secretion of TNF-α were significantly reduced (P= 0.017 and P= 0.0001, respectively) when the mast cells were inoculated with UV-treated Cpn, as compared to live bacteria (Fig. 4). In contrast, inactivation of Cpn failed to reduce the expression and secretion of MCP-1. Finally, UV-treatment of either strain of Aa had only minor effects on the expression and secretion of cytokines (Fig. 4).

Bottom Line: Human monocyte-derived macrophages that were pre-infected with Cpn also induced a significant pro-inflammatory response in human mast cells, both in cocultures and when preconditioned media from Cpn-infected macrophages were used.Intranasal and intravenous administration of live Cpn and Aa, respectively induced an accumulation of activated mast cells in the aortic sinus of apolipoprotein E-deficient mice, however, with varying responses in the systemic levels of lipopolysaccharide (LPS) and TNF-alpha.Pro-atherogenic Cpn and Aa induce a pro-inflammatory response in cultured human connective tissue-type mast cells and activation of mouse aortic mast cells in vivo.

View Article: PubMed Central - PubMed

Affiliation: Wihuri Research Institute, Kalliolinantie, Helsinki, Finland.

ABSTRACT
A broad variety of microbes are present in atherosclerotic plaques and chronic bacterial infection increases the risk of atherosclerosis by mechanisms that have remained vague. One possible mechanism is that bacteria or bacterial products activate plaque mast cells that are known to participate in the pathogenesis of atherosclerosis. Here, we show by real-time PCR analysis and ELISA that Chlamydia pneumoniae (Cpn) and a periodontal pathogen, Aggregatibacter actinomycetemcomitans (Aa), both induce a time and concentration-dependent expression and secretion of interleukin 8 (IL-8), tumour necrosis factor-alpha (TNF-alpha) and monocyte chemoattractant protein-1 (MCP-1) by cultured human peripheral blood-derived mast cells, but not anti-inflammatory molecules, such as IL-10 or transforming growth factor beta 1 (TGF-beta 1). The IL-8 and MCP-1 responses were immediate, whereas the onset of TNF-alpha secretion was delayed. The Cpn-mediated pro-inflammatory effect was attenuated when the bacteria were inactivated by UV-treatment. Human monocyte-derived macrophages that were pre-infected with Cpn also induced a significant pro-inflammatory response in human mast cells, both in cocultures and when preconditioned media from Cpn-infected macrophages were used. Intranasal and intravenous administration of live Cpn and Aa, respectively induced an accumulation of activated mast cells in the aortic sinus of apolipoprotein E-deficient mice, however, with varying responses in the systemic levels of lipopolysaccharide (LPS) and TNF-alpha. Pro-atherogenic Cpn and Aa induce a pro-inflammatory response in cultured human connective tissue-type mast cells and activation of mouse aortic mast cells in vivo.

Show MeSH
Related in: MedlinePlus