Differential expression of CD95, Bcl‐2, and Bax in rat gastric chief and parietal cells

Abstract

Apoptotic cell death is common in the inflamed gastric mucosa, but its role in the regulation of cell homeostasis in normal gastric mucosa is unknown. We investigated the expression of CD95, Bcl-2, and Bax and their roles in the regulation of apoptosis in normal rat gastric mucosa and in cultures of highly enriched rat chief and parietal cells by immunostaining, Western blotting, and FACS. In intact tissue CD95, Bcl-2, and Bax were localized predominantly in the glandular base region in chief cells. In freshly isolated cells, expression of CD95, Bcl-2, and Bax was much more pronounced in chief cells than in parietal cells. A lower intracellular Bcl-2/Bax ratio suggesting a higher susceptibility to apoptosis was noticed in chief rather than in parietal cells. In extended cultures of parietal and chief cells, Bax expression was upregulated and Bcl-2 expression was downregulated. These regulatory changes, presumably caused by in vitro effects, were not associated with an increase in spontaneous apoptosis. Treatment of chief and parietal cells with Fas-ligand induced apoptosis of all CD95 expressing cells. Expression of CD95, Bcl-2, and Bax predominantly in chief cells suggests that in this cell type regulation of apoptosis may differ from that in parietal cells. Binding of FasL with functionally active CD95 receptors on chief and parietal cells may be relevant for induction of apoptosis in inflamed gastric mucosa.

Hepatocyte growth factor regulates the development of highly pure cultured chief cells from rat stomach by stimulating chief cell proliferation in vitro

“…Chief cell cultures made from these highly purified cells were used 2 days after seeding, but it was not mentioned whether they were confluent or not. Additionally, it was demonstrated that cultures made from highly purified chief cells showed a significant reduction in the expression of some proteins found in mature chief cells in vivo (20). Our results show that chief cells in culture must be confluent with a high cell density to, both functionally and structurally, express a phenotype that is similar to chief cells, in vivo.…”

“…Although this has been accomplished before with chief cells isolated from the dog stomach (2,26,27), such a culture system in rodent species has not been described. In previous studies using chief cells isolated from the rat stomach, cultures were made either by using mixed mucosal cells with no purification (30,31) or by preparing highly purified chief cells (85 Ϯ 11% pure) by elutriation and Percoll density gradient centrifugation (20). Chief cell cultures made from these highly purified cells were used 2 days after seeding, but it was not mentioned whether they were confluent or not.…”

“…For this, cells isolated by collagenase digestion were purified by centrifugal elutriation to yield cultures with a high transepithelial resistance (TER) and low permeability that maintained differentiated function as shown by agonist-induced pepsinogen secretion (2,26). Since the procedure was developed, short-term cultures have been produced from isolated human and rabbit (10), guinea pig (25), pig (12), and rat (20,30,31) chief cells. Although isolated chief cells and short-term cultured cells from all species secrete pepsinogen (10,12,25,31), it is not currently possible to produce a confluent monolayer of chief cells with a high TER, low permeability, and high rate of agonist-induced pepsinogen secretion from a species other than dog.…”

“…Animals used for this study were maintained in accordance with the guidelines of the Committee on Animals at the Beth Israel Deaconess Medical Center and all animal experiments were done with IACUC-approved protocols. Isolated chief cells were prepared from the rat stomach (Sprague-Dawley; Taconic, Germantown, NY) by density gradient and centrifugal elutriation techniques as described previously by others (3)(4)(5)(6)(7)20) and modified by us to obtain highly enriched chief cells from the rat stomach. In brief, nonfasted rats, weighing no more than 200 g, were anesthetized with pentobarbital sodium.…”

Overcoming Fas-Mediated Apoptosis Accelerates Helicobacter-Induced Gastric Cancer in Mice

“…Apoptosis mediated through the Fas antigen surface receptor pathway plays a central role in Helicobacter-induced gastric mucosal disease in which Fas signaling facilitates parietal and chief cell depletion early in infection (30)(31)(32). Surface Fas antigen expression is markedly up-regulated in the gastric mucosa during infection (33) and is expressed at the highest levels on chief and parietal cell populations.…”