Increased protein level of PEPT1 intestinal H+-peptide cotransporter upregulates absorption of glycylsarcosine and ceftibuten in 5/6 nephrectomized rats (original) (raw)
Related papers
Intestinal peptide transport: ex vivo uptake studies and localization of peptide carrier PEPT1
American journal of physiology. Gastrointestinal and liver physiology, 2001
The nature of protein breakdown products and peptidomimetic drugs such as beta-lactams is crucial for their transmembrane transport across apical enterocyte membranes, which is accomplished by the pH-dependent high-capacity oligopeptide transporter PEPT1. To visualize oligopeptide transporter-mediated uptake of oligopeptides, an ex vivo assay using the fluorophore-conjugated dipeptide derivative D-Ala-Lys-N(epsilon)-7-amino-4-methylcoumarin-3-acetic acid (D-Ala-Lys-AMCA) was established in the murine small intestine and compared with immunohistochemistry for PEPT1 in murine and human small intestine. D-Ala-Lys-AMCA was accumulated by enterocytes throughout all segments of the murine small intestine, with decreasing intensity from the top to the base of the villi. Goblet cells did not show specific uptake. Inhibition studies revealed competitive inhibition by the beta-lactam cefadroxil, the angiotensin-converting enzyme inhibitor captopril, and the dipeptide glycyl-glutamine. Control...
Amino acid absorption and homeostasis in mice lacking the intestinal peptide transporter PEPT1
American Journal of Physiology-Gastrointestinal and Liver Physiology, 2011
The intestinal peptide transporter PEPT1 mediates the uptake of di- and tripeptides derived from dietary protein breakdown into epithelial cells. Whereas the transporter appears to be essential to compensate for the reduced amino acid delivery in patients with mutations in amino acid transporter genes, such as in cystinuria or Hartnup disease, its physiological role in overall amino acid absorption is still not known. To assess the quantitative importance of PEPT1 in overall amino acid absorption and metabolism, PEPT1-deficient mice were studied by using brush border membrane vesicles, everted gut sacs, and Ussing chambers, as well as by transcriptome and proteome analysis of intestinal tissue samples. Neither gene expression nor proteome profiling nor functional analysis revealed evidence for any compensatory changes in the levels and/or function of transporters for free amino acids in the intestine. However, most plasma amino acid levels were increased in Pept1−/−compared with Pep...
An update on renal peptide transporters
American journal of physiology. Renal physiology, 2003
The brush-border membrane of renal epithelial cells contains PEPT1 and PEPT2 proteins that are rheogenic carriers for short-chain peptides. The carrier proteins display a distinct surface expression pattern along the proximal tubule, suggesting that initially di- and tripeptides, either filtered or released by surface-bound hydrolases from larger oligopeptides, are taken up by the low-affinity but high-capacity PEPT1 transporter and then by PEPT2, which possesses a higher affinity but lower transport capacity. Both carriers transport essentially all possible di- and tripeptides and numerous structurally related drugs. A unique feature of the mammalian peptide transporters is the capability of proton-dependent electrogenic cotransport of all substrates, regardless of their charge, that is achieved by variable coupling in proton movement along with the substrate down the transmembrane potential difference. This review focuses on the postcloning research efforts to understand the molec...
AJP: Renal Physiology, 2006
Renal mass reduction is associated with a compromise in renal excretion, and thus dosages of drugs need to be adjusted to avoid adverse reactions and to ensure their effectiveness. A prototypic example is patients who had undergone transplantation due to a variety of causes, including diabetic nephropathy; the latter appears to be the major cause of renal failure requiring hemodialysis and transplantation. Conceivably, hyperglycemia with reduced renal mass interferes in the delivery of xenobiotics handled by various tubular transporters. In this investigation, effect of renal mass reduction/hyperglycemia on gene and protein expression of P-glycoprotein (Pgp), PEPT1, and PEPT2 was assessed. Also, [H(3)]glycylsarcosine uptake, a prototype of dipeptide, was measured in various groups of rats: sham-operated, uninephrectomized, streptozotocin-induced diabetes, and diabetic + uninephrectomized. An increase in Pgp, PEPT1, and PEPT2 expression was observed in kidneys of uninephrectomy rats, the highest being in the Pgp. Similarly, an increase was observed in diabetic rats who had undergone uninephrectomy, although less than those with nephrectomy alone. No differences were observed between sham-operated and diabetic groups. Increased uptake of [H(3)]glycylsarcosine was also seen in uninephrectomised rats. A modest uptake was observed in diabetic rats who had undergone uninephrectomy. The data suggest that uninephrectomy induces an increase in the expression and activity of transporters localized to renal tubular epithelial brush border. The fact that upregulation and activity of the peptide transporters were less in kidneys of diabetic animals who had undergone uninephrectomy compared with uninephrectomy alone suggests that hyperglycemia interferes in their expression and activity during the compensatory phase.
Comparison of urine and plasma peptidome indicates selectivity in renal peptide handling
Proteomics. Clinical applications, 2018
Urine is considered to be produced predominantly as a result of plasma filtration in the kidney. However, the origin of the native peptides present in urine has never been investigated in detail. Therefore, we aimed to obtain a first insight into the origin of urinary peptides based on a side-by-side comprehensive analysis of the plasma and urine peptidome. Twenty-two matched urine and plasma samples were analyzed for their peptidome using capillary electrophoresis coupled to mass spectrometry (CE-MS; for relative quantification) and CE- or LC coupled to tandem mass spectrometry (CE- or LC- MS/MS; for peptide identification). The overlap and association of abundance of the different peptides present in these two body fluids were evaluated. We were able to identify 561 plasma and 1461 urinary endogenous peptides. Only 90 peptides were detectable in both urine and plasma. No significant correlation was found when comparing the abundance of these common peptides, with the exception of ...
American journal of physiology. Gastrointestinal and liver physiology, 2017
Despite the fact that many membrane proteins carry extracellular glycans, little is known about whether the glycan chains also affect protein function. We recently demonstrated that the proton-coupled oligopeptide transporter 1 (PEPT1) in the intestine is glycosylated at six asparagine residues (N50, N406, N439, N510, N515, N532). Mutagenesis-induced disruption of the individual N-glycosylation site N50, which is highly conserved among mammals, was detected to significantly enhance the PEPT1 mediated inward transport of peptides. Here, we show for the murine protein, that the inhibition of glycosylation at sequon N50 by substituting N50 with glutamine, lysine or cysteine, or by replacing S52 with alanine, equally altered PEPT1 transport kinetics in oocytes. Further, we provide evidence that the uptake of [(14)C]-glycyl-sarcosine in immortalized murine small intestinal (Mode-K) or colonic epithelial (PTK-6) cells stably expressing the PEPT1 transporter N50Q is also significantly incr...
PLoS ONE, 2011
High-protein diets are effective in achieving weight loss which is mainly explained by increased satiety and thermogenic effects. Recent studies suggest that the effects of protein-rich diets on satiety could be mediated by amino acids like leucine or arginine. Although high-protein diets require increased intestinal amino acid absorption, amino acid and peptide absorption has not yet been considered to contribute to satiety effects. We here demonstrate a novel finding that links intestinal peptide transport processes to food intake, but only when a protein-rich diet is provided. When mice lacking the intestinal peptide transporter PEPT1 were fed diets containing 8 or 21 energy% of protein, no differences in food intake and weight gain were observed. However, upon feeding a high-protein (45 energy%) diet, Pept1 2/2 mice reduced food intake much more pronounced than control animals. Although there was a regain in food consumption after a few days, no weight gain was observed which was associated with a reduced intestinal energy assimilation and increased fecal energy losses. Pept1 2/2 mice on high-protein diet displayed markedly reduced plasma leptin levels during the period of very low food intake, suggesting a failure of leptin signaling to increase energy intake. This together with an almost twofold elevated plasma arginine level in Pept1 2/2 but not wildtype mice, suggests that a cross-talk of arginine with leptin signaling in brain, as described previously, could cause these striking effects on food intake.
The Histochemical journal, 1999
Peptide transporter-1 is a H+/peptide cotransporter responsible for the uptake of small peptides and peptide-like drugs, and is present in the absorptive epithelial cells of the villi in the small intestine (duodenum, jejunum, and ileum). It has been localized to the apical microvillous plasma membrane of the absorptive epithelial cells of the rat small intestine using the immunogold electron microscopic technique. Digital image analysis of the jejunum revealed that the transporter protein was abundant at the tip of the villus and that the amount decreased from the tip of the villus to its base. The effect of dietary administration of amino acids and starvation on the expression of PepT1 in the jejunum was examined by immunoblotting and image analysis of immunofluorescence. Starvation markedly increased the amount of peptide transporter present, whereas dietary administration of amino acids reduced it. The gradient of the transporter protein along the crypt-villus axis was maintaine...