Overexpression of ATP-activated P2X7 receptors in the intestinal mucosa is implicated in the pathogenesis of Crohn's disease.

Abstract

BACKGROUND:

Extracellular nucleotides released in conditions of cell stress alert the immune system from tissue injury or inflammation. We hypothesized that the P2X7 receptor (P2X7-R) could regulate key elements in inflammatory bowel disease pathogenesis.

METHODS:

Colonoscopy samples obtained from patients with Crohn's disease (CD), ulcerative colitis, and controls were used to analyze P2X7-R expression by RT and real-time PCR, immunohistochemistry, and confocal microscopy. Inflammatory response was determined by the levels of cytokines by enzyme-linked immunosorbent assay in cultures of intestinal explants. Apoptosis was determined by the TUNEL assay. P2X7-R C57BL/6 mice were treated with trinitrobenzene sulfonic acid or dextran sulfate sodium (DSS) for inducing colitis.

RESULTS:

P2X7-R was expressed in higher levels in inflamed CD epithelium and lamina propria, where it colocalizes more with dendritic cells and macrophages. Basal levels of P2X7-R mRNA were higher in CD inflamed mucosa compared with noninflamed CD and controls and were upregulated after interferon-γ in controls. Apoptotic rates were higher in CD epithelium and lamina propria compared with ulcerative colitis and controls. Levels of tumor necrosis factor-α, interleukin (IL)-1β, and IL-17 were higher, whereas IL-10 was lower in CD compared with controls. Levels of tumor necrosis factor-α-α and interleukin-1β increased after adenosine-triphosphate and decreased after KN62 treatment in CD. P2X7-R animals did not develop trinitrobenzene sulfonic acid or DSS colitis.

CONCLUSIONS:

The upregulation of P2X7-R in CD inflamed mucosa is consistent with the involvement of purinoceptors in inflammation and apoptosis. These observations may implicate purinergic signaling in the pathogenesis of intestinal inflammation, and the P2X7-R may represent a novel therapeutic target in CD.

• Authors: Adriane R Neves, Morgana T L Castelo-Branco, Vanessa R Figliuolo, Claudio Bernardazzi, Fernanda Buongusto, Agnes Yoshimoto, Hayandra F Nanini, Claudia M L M Coutinho, Antonio José V Carneiro, Robson Coutinho-Silva, Heitor S P de Souza
• Journal: Inflammatory bowel diseases (Inflamm Bowel Dis) Vol. 20 Issue 3 Pg. 444-57 (Mar 2014) ISSN: 1536-4844 [Electronic] England
• PMID: 24412990 (Publication Type: Comparative Study, Journal Article, Research Support, Non-U.S. Gov't)

Chemical References

• Interleukin-1beta
• RNA, Messenger
• Receptors, Purinergic P2X7
• Tumor Necrosis Factor-alpha
• Interleukin-10
• Interferon-gamma
• Adenosine Triphosphate

Topics

• Adenosine Triphosphate (metabolism)
• Adolescent
• Adult
• Animals
• Apoptosis
• Blotting, Western
• Case-Control Studies
• Colitis, Ulcerative (genetics, metabolism, pathology)
• Colonoscopy
• Crohn Disease (genetics, metabolism, pathology)
• Enzyme-Linked Immunosorbent Assay
• Female
• Fluorescent Antibody Technique
• Follow-Up Studies
• Humans
• Interferon-gamma (metabolism)
• Interleukin-10 (genetics, metabolism)
• Interleukin-1beta (genetics, metabolism)
• Intestinal Mucosa (metabolism)
• Male
• Mice
• Mice, Inbred C57BL
• Mice, Knockout
• Middle Aged
• Prognosis
• RNA, Messenger (genetics)
• Real-Time Polymerase Chain Reaction
• Receptors, Purinergic P2X7 (physiology)
• Reverse Transcriptase Polymerase Chain Reaction
• Tumor Necrosis Factor-alpha (genetics, metabolism)
• Young Adult