To investigate the pathogenic mechanism of ulcerative colitis, a dextran sulfate sodium (DSS)-induced acute colitis model was examined by serum metabolomic analysis. Higher levels of stearoyl lysophosphatidylcholine and lower levels of oleoyl lysophosphatidylcholine in DSS-treated mice compared to controls led to the identification of DSS-elicited inhibition of stearoyl-CoA desaturase 1 (SCD1) expression in liver. This decrease occurred prior to the symptoms of acute colitis and was well correlated with elevated expression of proinflammatory cytokines. Furthermore, Citrobacter rodentium-induced colitis and lipopolysaccharide treatment also suppressed SCD1 expression in liver. Scd1 null mice were more susceptible to DSS treatment than wild-type mice, while oleic acid feeding and in vivo SCD1 rescue with SCD1 adenovirus alleviated the DSS-induced phenotype. This study reveals that inhibition of SCD1-mediated oleic acid biogenesis exacerbates proinflammatory responses to exogenous challenges, suggesting that SCD1 and its related lipid species may serve as potential targets for intervention or treatment of inflammatory diseases.
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We thank V.I. Zannis for providing adenovirus expressing SCD1 and S. Kimura for control adenovirus. We also appreciate the technical assistance of J. Buckley, U. Jaowattana, and T. Tanabe. J.R.I. is grateful to US Smokeless Tobacco Company for a grant for collaborative research. This study was supported by the NCI Intramural Research Program of the NIH.