Wee JLK, Chionh YT, Ng GZ, Harbour SN, Allison C, Pagel CN, Mackie EJ, Mitchell HM, Ferrero RL, Sutton P. Protease-activated receptor-1 down-regulates the murine inflammatory and humoral response to Helicobacter pylori.
Gastroenterology 2010;
138:573-82. [PMID:
19706295 DOI:
10.1053/j.gastro.2009.08.043]
[Citation(s) in RCA: 27] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2009] [Revised: 07/17/2009] [Accepted: 08/10/2009] [Indexed: 01/13/2023]
Abstract
BACKGROUND & AIMS
Helicobacter pylori infection results in a diversity of pathologies, from asymptomatic gastritis to adenocarcinoma. The reason for these diverse outcomes is multifactorial and includes host factors that regulate severity of Helicobacter-induced gastritis. Protease-activated receptors (PAR) are environmental sensors that can detect tissue damage and pathogens. Whereas PAR-2 has proinflammatory activity and PAR-1 can protect the gastric mucosa against chemical damage, neither has previously been examined for their potential roles in regulating Helicobacter pathogenesis.
METHODS
PAR-1(-/-), PAR-2(-/-), and wild-type mice were infected with H pylori for up to 2 months then colonization levels determined by colony-forming assay, gastritis by histology, and serum antibody levels by enzyme-linked immunosorbent assay. Responsiveness of primary epithelial cells to PAR-1 activation was assessed by calcium mobilization assay. Primary epithelial cells, macrophages, and dendritic cells were cocultured with H pylori and nuclear factor (NF)-kappaB, and cytokine secretion was determined by enzyme-linked immunosorbent assay.
RESULTS
Two months postinfection, H pylori levels were significantly reduced in PAR-1(-/-) and increased in PAR-2(-/-) mice. This effect on colonization was inversely correlated with inflammation severity. Infection of PAR-1(-/-) mice induced an increased serum antibody response. Primary epithelial cells were activated by a PAR-1-activating peptide. H pylori stimulation of primary epithelial cells, but not macrophages or dendritic cells, from PAR-1(-/-) mice induced increased levels of NF-kappaB and the proinflammatory cytokine macrophage-inflammatory protein (MIP)-2. PAR-1 also down-regulated MIP-2 secretion in response to cag pathogenicity island activity.
CONCLUSIONS
PAR-1 protects the host against severe Helicobacter-induced gastritis. This may be mediated by suppressing the production of proinflammatory cytokines such as MIP-2.
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