Intra- and extracellular proteins in human normal and polycystic kidney epithelial cells

A tissue culture method was established for the continuous growth of epithelial cells from the cortex of human normal kidney (HNC) and from the epithelial layer of kidney cysts from autosomal dominant polycystic kidney disease (ADPKD) patients. Primary cells were grown to 80 to 90% confluency from 1 mm2 slices of tissue, and subcultured up to 10 times. The subcultured HNC and ADPKD cells retained characteristic epithelial polygonal and elongated shape and positive immunofluorescent staining for cytokeratin. The cell doubling time for both HNC and ADPKD epithelia was three to four days at a fetal calf serum (FCS) concentration of 5%. Using these culturing procedures 1 to 5 x 10(9) epithelial cells could be obtained from each kidney specimen. Profiles of 35S-methionine radiolabeled intracellular proteins of HNC and ADPKD cells qualitatively demonstrated a high degree of similarity, thus confirming a similarity of epithelial origin and protein biosynthesis. Both the underexpression of three proteins (a) protein p2, Mr approximately 47 kDa, pI approximately 6.0; b) protein p3, Mr approximately 50 kDa, pI approximately 5.9; and c) protein p4, Mr approximately 44 kDa, pI approximately 5.8) and the overexpression of several proteins (including: a) p5, Mr approximately 56 kDa, pI approximately 7.3; b) protein p6, Mr approximately 32 kDa, pI approximately 7.3; c) protein p7, Mr approximately 33 kDa, pI approximately 5.3; d) protein p8, Mr approximately 45 kDa, pI approximately 6.9; e) protein p9, Mr approximately 35 kDa, pI approximately 6.7; and f) protein p10, Mr approximately 30 kDa, pI approximately 6.6) were found in ADPKD cells.(ABSTRACT TRUNCATED AT 250 WORDS)