Separation of Dual Oxidase 2 and Lactoperoxidase Expression in Intestinal Crypts and Species Differences May Limit Hydrogen Peroxide Scavenging During Mucosal Healing in Mice and Humans. Issue 1 (19th December 2017)

• Record Type: Journal Article
• Authors: Rigoni, Alice; Poulsom, Richard; Jeffery, Rosemary; Mehta, Shameer; Lewis, Amy; Yau, Christopher; Giannoulatou, Eleni; Feakins, Roger; Lindsay, James O; Colombo, Mario P; Silver, Andrew
• Is Part Of: Inflammatory bowel diseases. Volume 24:Issue 1(2018)
• Page Start: 136
• Page End: 148
• Publication Date: 2017-12-19
• Subjects: colitis -- Duox2 -- gut pathogens -- host defense -- hydrogen peroxide -- thiocyanate; Inflammatory bowel diseases -- Periodicals; Colitis, Ulcerative -- Periodicals; Crohn Disease -- Periodicals; Inflammatory Bowel Diseases -- Periodicals; 616.344
• DOI: 10.1093/ibd/izx024
• Languages: English
• ISSNs: 1078-0998

Abstract

Abstract: Background: DUOX2 and DUOXA2 form the predominant H2 O2 -producing system in human colorectal mucosa. Inflammation, hypoxia, and 5-aminosalicylic acid increase H2 O2 production, supporting innate defense and mucosal healing. Thiocyanate reacts with H2 O2 in the presence of lactoperoxidase (LPO) to form hypothiocyanate (OSCN-), which acts as a biocide and H2 O2 scavenging system to reduce damage during inflammation. We aimed to discover the organization of Duox2, Duoxa2, and Lpo expression in colonic crypts of Lieberkühn (intestinal glands) of mice and how distributions respond to dextran sodium sulfate (DSS)-induced colitis and subsequent mucosal regeneration. Methods: We studied tissue from DSS-exposed mice and human biopsies using in situ hybridization, reverse transcription quantitative polymerase chain reaction, and cDNA microarray analysis. Results: Duox2 mRNA expression was mostly in the upper crypt quintile while Duoxa2 was more apically focused. Most Lpo mRNA was in the basal quintile, where stem cells reside. Duox2 and Duoxa2 mRNA were increased during the induction and resolution of DSS colitis, while Lpo expression did not increase during the acute phase. Patterns of Lpo expression differed from Duox2 in normal, inflamed, and regenerative mouse crypts ( P < 0.001). We found no evidence of LPO expression in the human gut. Conclusions: The spatial and temporal separation of H2 O2 -consuming and -producing enzymes enables a thiocyanate- H2 O2 "scavenging" system in murine intestinal crypts to protect the stem/proliferative zones from DNA damage, while still supporting higher H2 O2 concentrations apically to aid mucosal healing. The absence of LPO expression in the human gut suggests an alternative mechanism or less protection from DNA damage during H2 O2 -driven mucosal healing.