CD38 Is Expressed on Inflammatory Cells of the Intestine and Promotes Intestinal Inflammation

The enzyme CD38 is expressed on a variety of hematopoietic and non-hematopoietic cells and is involved in diverse processes such as generation of calcium-mobilizing metabolites, cell activation, and chemotaxis. Here, we show that under homeostatic conditions CD38 is highly expressed on immune cells of the colon mucosa of C57BL/6 mice. Myeloid cells recruited to this tissue upon inflammation also express enhanced levels of CD38. To determine the role of CD38 in intestinal inflammation, we applied the dextran sulfate sodium (DSS) colitis model. Whereas wild-type mice developed severe colitis, CD38^-/- mice had only mild disease following DSS-treatment. Histologic examination of the colon mucosa revealed pronounced inflammatory damage with dense infiltrates containing numerous granulocytes and macrophages in wild-type animals, while these findings were significantly attenuated in CD38^-/- mice. Despite attenuated histological findings, the mRNA expression of inflammatory cytokines and chemokines was only marginally lower in the colons of CD38^-/- mice as compared to wild-type mice. In conclusion, our results identify a function for CD38 in the control of inflammatory processes in the colon.