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Acute Pancreatitis Involves Alterations in the Transport of Amino Acids Necessary for Glutathione Synthesis
Author(s) -
Kuster Evelyne,
Graf Rolf,
Verrey François,
Camargo Simone Mafalda
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.968.7
Subject(s) - glutathione , glutamine , cystine , glycine , chemistry , glutamate receptor , biochemistry , acinar cell , cysteine , amino acid , glutathione synthetase , microbiology and biotechnology , biology , pancreas , enzyme , receptor
Acute pancreatitis (AP) is a serious inflammatory disease of the exocrine pancreas. During its pathogenesis, reactive oxygen species (ROS) have deleterious effects and they can be neutralised by glutathione (GSH), an intracellular antioxidant. GSH is synthesised from glutamate, glycine and cysteine but amino acid transport into acinar cells remains poorly understood. It is the aim of this work to characterise the transport of glycine, glutamate and cysteine (as well as their precursors glutamine and cystine) for the production of GSH during AP in isolated pancreatic acinar cells. For this purpose, AP was induced in C57BL6/J mice using supraphysiological doses of cerulein (12 times hourly 50μg/kg intraperitoneally) and acinar cells were isolated 12, 24, 36 and 72 hours after the first injection. Glutamate, glycine and cysteine concentrations are rapidly depleted in acinar cells during AP. Concurrently, gene expression levels of enzymes necessary for GSH synthesis are increased. Levels of free GSH (oxidised and reduced) are initially diminished but they are increased during the following regeneration phase. Gene expression levels of the acinar glutamine transporters (LAT1 ( slc7a5 ), LAT2 ( slc7a8 ), SNAT2 ( slc38a2 ), SNAT3 ( slc38a3 ) and SNAT5 ( slc38a5 ) as well as the glycine transporter GlyT1 ( slc6a9 ) are impaired during AP, while the cystine/glutamate exchanger xCT ( slc7a11 ) is remarkably increased during the early phase. Immunofluorescence analysis revealed low xCT expression on pancreatic acinar cells during the healthy state, whereas the protein level increases significantly during AP, as was also shown via Western blotting. Uptake experiments using radiolabelled cystine confirmed an enhanced capacity of isolated acinar cells to import cystine during AP, presumably via the up‐regulated xCT protein levels. Our data suggests that acinar cells adapt amino acid transport and enzymes necessary for GSH synthesis to match the cells’ needs in the oxidative stress situation occurring during AP. Specifically, xCT expression is up‐regulated in acinar cells to enhance cystine import, the rate‐limiting factor of GSH synthesis.