Eicosanoid production by a differentiated canine colonic epithelial cell line, VNCC

Abstract

Background/Aims: The lack of pure, proliferative, but not transformed intestinal epithelial cells has impeded progress in understanding their role in chronic intestinal inflammation. To clarify that role, the present study characterized the epithelial cell line VNCC, derived from normal adult dog distal colon. Methods: Cells were cultured on plastic and permeable supports for analysis of eicosanoid production (by radioimmunoassay and high-performance liquid chromatography) and transport characteristics (by Ussing chamber short-circuit determinations). Results: In culture, VNCC formed confluent monolayers and domes, suggesting formation of tight junctions and active solute absorption. When cultured on permeable supports, VNCC developed modest, but variable, transepithelial resistances (563 ± 94 Ω/cm2) with a spontaneous short-circuit current of 5.0 ± 0.4 μA/ cm2. Forskolin caused a prolonged increase in the short-circuit current, inhibited by amiloride but not bumetanide, suggesting that VNCC display 5′-cyclic adenosine monophosphate-stimulated sodium absorption. VNCC incubated with arachidonic acid released a variety of eicosanoids including 6-keto-prostaglandin (PG)F1α, PGE2, thromboxane B2, and PGF2α, but no hydroxyarachidonate metabolites. Bradykinin stimulated VNCC eicosanoid release. Conclusions: The ability of VNCC to divide and differentiate in culture, to form polarized monolayers capable of active sodium absorption, and to respond to inflammatory mediators with eicosanoid release makes them a unique tool for the study of the interactions of inflammation on colonocyte function.