Article Text
Abstract
Objective: Sulfate (SO42−) is an abundant component of intestinal mucins and its content is decreased in certain gastrointestinal diseases, including inflammatory bowel disease. In this study, the hyposulfataemic NaS1 sulfate transporter null (Nas1−/−) mice were used to investigate the physiological consequences of disturbed sulfate homeostasis on (1) intestinal sulfomucin content and mRNA expression; (2) intestinal permeability and proliferation; (3) dextran sulfate sodium (DSS)-induced colitis; and (4) intestinal barrier function against the bacterial pathogen, Campylobacter jejuni.
Methods: Intestinal sulfomucins and sialomucins were detected by high iron diamine staining, permeability was assessed by fluorescein isothiocyanate (FITC)–dextran uptake, and proliferation was assessed by 5-bromodeoxyuridine (BrdU) incorporation. Nas1−/− and wild-type (Nas1+/+) mice received DSS in drinking water, and intestinal damage was assessed by histological, clinical and haematological measurements. Mice were orally inoculated with C jejuni, and intestinal and systemic infection was assessed. Ileal mRNA expression profiles of Nas1−/− and Nas1+/+ mice were determined by cDNA microarrays and validated by quantitative real-time PCR.
Results: Nas1−/− mice exhibited reduced intestinal sulfomucin content, enhanced intestinal permeability and DSS-induced colitis, and developed systemic infections when challenged orally with C jejuni. The transcriptional profile of 41 genes was altered in Nas1−/− mice, with the most upregulated gene being pancreatic lipase-related protein 2 and the most downregulated gene being carbonic anhydrase 1 (Car1).
Conclusion: Sulfate homeostasis is essential for maintaining a normal intestinal metabolic state, and hyposulfataemia leads to reduced intestinal sulfomucin content, enhanced susceptibility to toxin-induced colitis and impaired intestinal barrier to bacterial infection.
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Footnotes
▸ An additional table and figure are published online only at http://gut.bmj.com/content/vol58/issue7
Competing interests: None.
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