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Chemokines produced by mesothelial cells: huGRO-alpha, IP-10, MCP-1 and RANTES
C E Visser1, J Tekstra, J J Brouwer-Steenbergen
1Department of Cell Biology and Immunology, Faculty of Medicine, Vrije Universiteit, Amsterdam, The Netherlands.
Abstract:
Recently we showed the in vivo relevance of chemokines in cases of bacterial peritonitis in continuous ambulatory peritoneal dialysis (CAPD) patients. Mesothelial cells, the most numerous cells in the peritoneal cavity, are hypothesized to function as a main source of chemokine production. We investigated the time- and dose-dependent expression patterns of four chemokines by mesothelial cells at the mRNA and protein level in response to stimulation with physiological doses of proinflammatory mediators that are present at the site of bacterial inflammation. Besides the chemokines huGRO-alpha (attractant for neutrophils), MCP-1 and RANTES (monocyte attractants), the expression and production of IP-10 was analysed. Mesothelial cells were cultured and stimulated with either IL-1beta, tumour necrosis factor-alpha (TNF-alpha) or IFN-gamma or combinations of these. The time- and dose-dependent mRNA expression of the chemokines was determined by Northern blot analysis and the protein production by ELISA. It was concluded that mesothelial cells could indeed be triggered by the mentioned stimuli to induce mRNA and protein production (huGRO-alpha and IP-10) or to augment constitutive protein production (MCP-1). However, RANTES mRNA and protein production could only be induced in some cases and only in small amounts. The chemokine response of mesothelial cells was regulated differentially, depending on the stimulus and the chemokine measured. In distinct cases, combination of the stimuli led to synergy in mRNA expression and protein production. The presented in vitro data support our hypothesis that mesothelial cells in vivo are the main source of relevant chemokines in response to proinflammatory mediators, suggesting an important role for mesothelial cells in host defence.
Insights
Mesothelial cells produce key chemokines like huGRO-alpha and IP-10 in response to inflammation, supporting their role in host defense during bacterial peritonitis in peritoneal dialysis patients.
Area of Science:
- Immunology
- Cell Biology
- Peritoneal Dialysis
Background:
- Bacterial peritonitis is a complication in continuous ambulatory peritoneal dialysis (CAPD) patients.
- Mesothelial cells are abundant in the peritoneal cavity and hypothesized to be a primary source of chemokines.
Purpose of the Study:
- To investigate the time- and dose-dependent expression of four chemokines (huGRO-alpha, MCP-1, RANTES, IP-10) by mesothelial cells.
- To determine if mesothelial cells produce chemokines in response to proinflammatory mediators found in bacterial inflammation.
Main Methods:
- Mesothelial cells were cultured and stimulated with IL-1beta, TNF-alpha, IFN-gamma, or combinations.
- Chemokine mRNA expression was analyzed using Northern blot.
- Protein production was quantified via ELISA.
Main Results:
- Mesothelial cells produced huGRO-alpha and IP-10 mRNA and protein upon stimulation.
- MCP-1 protein production was augmented, while RANTES production was limited.
- Stimulus combinations sometimes showed synergistic effects on chemokine expression.
Conclusions:
- Mesothelial cells are stimulated by inflammatory mediators to produce chemokines, supporting their role as a major source in vivo.
- This chemokine production by mesothelial cells is crucial for host defense mechanisms in bacterial peritonitis.