Morphological and molecular characterization of human gastric mucous cells in long-term primary culture

A primary cell culture of human gastric mucous cells was developed using enzymatic treatment of surgically obtained gastric mucosal specimens. Preferential attachment of gastric mucous cells during a preincubation step resulted in the enrichment of mucous cells [over 90% stained with periodic acid-Schiff (PAS) and mucin-type lectins] in the primary cell culture. Gastric mucous cells could be maintained in culture for 10 days. DNA synthesis peaked during the first 2 days in culture (8+/-1% bromodeoxyuridine-positive cells). During the entire culture period gastric mucous cells released high-molecular-weight glycoproteins into the medium, as determined by gel chromatography on a Sepharose CL-4B column and by metabolic labelling with [14C]-N-acetylglucosamine. Gastric mucin was verified by gas chromatographic analysis of the carbohydrate composition and fractionation of the void-volume fraction by density gradient centrifugation. Determination of the terminal glycosylation of the secreted glycoproteins by a lectin-ELISA revealed that there was a high quantity of alpha-l-fucose. Prostaglandin E2 significantly stimulated glycoprotein secretion during the entire cultivation period by 29-60%. Analysis of mucin-encoding MUC mRNA expression by reverse transcriptase polymerase chain reaction revealed that gastric mucous cells predominantly express MUC1 and MUC5AC, and to a lesser extent MUC6, which reflects the expression pattern obtained following analysis of biopsied samples of gastric mucosa. This primary cell culture model enables the regulation of mucin secretion and mucin gene expression in man to be investigated.