Profiling at mRNA, protein, and metabolite levels reveals alterations in renal amino acid handling and glutathione metabolism in kidney tissue of Pept2-/- mice.
Physiol Genomics, 2007/2/12;28(3):301-10.
Frey IM[1], Rubio-Aliaga I, Siewert A, Sailer D, Drobyshev A, Beckers J, de Angelis MH, Aubert J, Bar Hen A, Fiehn O, Eichinger HM, Daniel H
Affiliations
PMID: 17077276
Impact factor: 4.297
Abstract
PEPT2 is an integral membrane protein in the apical membrane of renal epithelial cells that operates as a rheogenic transporter for di- and tripeptides and structurally related drugs. Its prime role is thought to be the reabsorption of filtered di- and tripeptides contributing to amino acid homeostasis. To elucidate the role of PEPT2 in renal amino acid metabolism we submitted kidney tissues of wild-type and a Pept2(-/-) mouse line to a comprehensive transcriptome, proteome and metabolome profiling and analyzed urinary amino acids and dipeptides. cDNA microarray analysis identified 147 differentially expressed transcripts in transporter-deficient animals, and proteome analysis by 2D-PAGE and MALDI-TOF-MS identified 37 differentially expressed proteins. Metabolite profiling by GC-MS revealed predominantly altered concentrations of amino acids and derivatives. Urinary excretion of amino acids demonstrated increased glycine and cysteine/cystine concentrations and dipeptides in urine were assessed by amino acid analysis of urine samples before and after in vitro dipeptidase digestion. Dipeptides constituted a noticeable fraction of urinary amino acids in Pept2(-/-) animals, only, and dipeptide-bound glycine and cystine were selectively increased in Pept2(-/-) urine samples. These findings were confirmed by a drastically increased excretion of cysteinyl-glycine (cys-gly). Urinary loss of cys-gly together with lower concentrations of cysteine, glycine, and oxoproline in kidney tissue and altered expression of mRNA and proteins involved in glutathione (GSH) metabolism suggests that PEPT2 is predominantly a system for reabsorption of cys-gly originating from GSH break-down, thus contributing to resynthesis of GSH.
MeSH terms
Amino Acids; Animals; Dipeptides; Electrophoresis, Gel, Two-Dimensional; Gene Expression Profiling; Glutathione; Kidney; Mice; Mice, Inbred C57BL; Mice, Knockout; Models, Biological; Oligonucleotide Array Sequence Analysis; Proteomics; RNA, Messenger; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization; Symporters
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