Retention of differentiated properties in an established dog kidney epithelial cell line (MDCK).

Abstract

Madin-Darby canine kidney (MDCK) cells grown in tissue culture have the morphological properties of distal tubular epithelial cells, form tight junctions and lack several proximal tubular enzyme markers. Adenylate cyclase in these cells was stimulated by vasopressin, oxytocin, prostaglandins E1 and E2, glucagon and cholera toxin. Homrone-stimulated adenylate cyclase activity in isolated membrane preparations was dependent on low concentrations of GTP and had the MgCl2 and pH optima expected for the kidney enzyme. The MDCK cell line may retain the differentiated properties of the kidney epithelial cell of origin. When MDCK cells were injected into baby nude mice, continuous nodule growth was observed until adulthood was attained. Histological studies revealed the presence of 2 cell types: normal mouse fibroblasts which comprised 80-90% of the solid nodule mass, and MDCK cells, which formed epithelial sheets lining internal fluid-filled glands. EM analysis showed that the mucosal surfaces of the cells were characterized by microvilli which faced the lumen of the glands, that adjacent MDCK cells were joined by tight junctions, and that the serosal surfaces of the epithelial sheets were characterized by smooth plasma membranes which werelined by a continuous basement membrane. The MDCK cells may retain regional differentiation of their plasma membranes and the ability to regenerate kidney tubule-like structures in vivo.