In Vitro and Pharmacophore-Based Discovery of Novel hPEPT1 Inhibitors

Ekins, Sean; Johnston, Jessica; Bahadduri, Praveen M.; D'Souza, Vanessa M.; Ray, Abhijit; Chang, Cheng; Swaan, Peter W.

doi:10.1007/s11095-005-2505-y

Cited by 61 publications

(48 citation statements)

References 24 publications

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“…There is some evidence for interaction with proton-dependent active transporters: specifically, SLCO2B1 in the case of pravastatin and SLC15A1 in the case of fluvastatin. 27,28 SLCO2B1 is also implicated in hepatic uptake of pravastatin and has been examined for genetic contributions to interindividual variation in response to pravastatin. The main variant identified as having potential for pharmacogenetic response, marked by haplotype SLCO2B1*3, encodes a transporter of reduced function in vitro, but has not been associated with altered systemic drug exposure in vivo.…”

Section: Drug Transporter Proteins Affecting Statin Therapymentioning

confidence: 99%

Clinical implications of pharmacogenomics of statin treatment

Mangravite¹,

Thorn

Krauss³

2006

Pharmacogenomics J

145

132

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Section: Drug Transporter Proteins Affecting Statin Therapymentioning

confidence: 99%

Clinical implications of pharmacogenomics of statin treatment

Mangravite¹,

Thorn

Krauss³

2006

Pharmacogenomics J

145

132

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“…The PEPT1 pharmacophore was generated as described previously (12). The bacterial peptides were mapped onto this pharmacophore using ''Fast Fit'' algorithm and analyzed.…”

Section: Pharmacophore Mappingmentioning

confidence: 99%

Bacterial Peptide Recognition and Immune Activation Facilitated by Human Peptide Transporter PEPT2

Swaan¹,

Bensman²,

Bahadduri³

et al. 2008

Am J Respir Cell Mol Biol

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Microbial detection requires the recognition of pathogen-associated molecular patterns (PAMPs) by pattern recognition receptors (PRRs) that are distributed on the cell surface and within the cytosol. The nucleotide-binding oligomerization domain (NOD)-like receptor (NLR) family functions as an intracellular PRR that triggers the innate immune response. The mechanism by which PAMPs enter the cytosol to interact with NLRs, particularly muropeptides derived from the bacterial proteoglycan cell wall, is poorly understood. PEPT2 is a proton-dependent transporter that mediates the active translocation of di-and tripeptides across epithelial tissues, including the lung. Using computational tools, we initially established that bacterial dipeptides, particularly g-D-glutamyl-meso-diaminopimelic acid (g-iE-DAP), are suitable substrates for PEPT2. We then determined in primary cultures of human upper airway epithelia and transiently transfected CHO-PEPT2 cell lines that g-iE-DAP uptake was mediated by PEPT2 with an affinity constant of approximately 193 mM, whereas muramyl dipeptide was not transported. Exposure to g-iE-DAP at the apical surface of differentiated, polarized cultures resulted in activation of the innate immune response in an NOD1-and RIP2-dependent manner, resulting in release of IL-6 and IL-8. Based on these findings we report that PEPT2 plays a vital role in microbial recognition by NLR proteins, particularly with regard to airborne pathogens, thereby participating in host defense in the lung.Keywords: human; lung; bacterial; cell surface molecules; acute phase reactants Pathogen-associated molecular patterns (PAMPs) are recognized by cell surface or cytosolic pattern recognition receptors (PRRs) (1). One family of intracellular PRRs include the nucleotide-binding oligomerization domain (NOD)-containing proteins (NODs or NOD-like receptors [NLRs]) that sense intracellular pathogen invasion and trigger signaling cascades, thereby activating the host immune response (2-4). NOD1 and NOD2 mediate intracellular recognition of bacterial proteoglycan (PGN)-derived molecules through recognition by their carboxy-terminal leucine-rich repeat region (5). This results in recruitment of the downstream kinase protein RIP2 and initiation of NF-kB-mediated transcription and elaboration of newly synthesized cytokines and chemokines (6). Biochemical and functional analyses have identified g-D-glutamyl-mesodiaminopimelic acid (g-iE-DAP) and muramyl dipeptide (MDP) as the minimal bacterial muropeptide epitopes recognized by NOD1 and NOD2, respectively, resulting in immune activation (5, 7).Enzymes that are naturally present in the epithelial lining fluid (e.g., lysozyme) are believed to act in concert to degrade the bacterial cell wall as a front-line defense mechanism, thereby liberating muropeptide fragments that include both g-iE-DAP and MDP. The dipeptides may also be derived as byproducts of bacterial PGN biosynthesis, cell growth, and division; therefore, it is plausible that these particular PAMPs reside in the airway...

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“…These computational methods generally focused on diverse structures for agonists, rarely using close structural analogs (Ekins et al, 2007). Accurate predictions can be difficult due to the size and flexibility of the human PXR ligand binding domain; however, the combination of models for searching molecule databases represents a rapid way to prescreen molecules before in vitro testing, as demonstrated previously using pharmacophores for other proteins (Ekins et al, 2005a;Chang et al, 2006) as originally suggested with the first human PXR pharmacophore (Ekins and Erickson, 2002).…”

mentioning

confidence: 99%

A Comprehensive in Vitro and in Silico Analysis of Antibiotics That Activate Pregnane X Receptor and Induce CYP3A4 in Liver and Intestine

Yasuda

Ranade²,

Venkataramanan³

et al. 2008

Drug Metab Dispos

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ABSTRACT:We have investigated several in silico and in vitro methods to improve our ability to predict potential drug interactions of antibiotics. Our focus was to identify those antibiotics that activate pregnane X receptor (PXR) and induce CYP3A4 in human hepatocytes and intestinal cells. Human PXR activation was screened using reporter assays in HepG2 cells, kinetic measurements of PXR activation were made in DPX-2 cells, and induction of CYP3A4 expression and activity was verified by quantitative polymerase chain reaction, immunoblotting, and testosterone 6␤-hydroxylation in primary human hepatocytes and LS180 cells. We found that in HepG2 cells CYP3A4 transcription was activated strongly (>10-fold) by rifampin and troleandomycin; moderately (>7-fold) by dicloxacillin, tetracycline, clindamycin, griseofulvin, and (>4-fold) erythromycin; and weakly (>2.4-fold) by nafcillin, cefaclor, sulfisoxazole, and (>2-fold) cefadroxil and penicillin V. Similar although not identical results were obtained in DPX-2 cells. CYP3A4 mRNA and protein expression were induced by these antibiotics to differing extents in both liver and intestinal cells. CYP3A4 activity was significantly increased by rifampin (9.7-fold), nafcillin and dicloxacillin (5.9-fold), and weakly induced (2-fold) by tetracycline, sufisoxazole, troleandomycin, and clindamycin. Multiple pharmacophore models and docking indicated a good fit for dicloxacillin and nafcillin in PXR. These results suggest that in vitro and in silico methods can help to prioritize and identify antibiotics that are most likely to reduce exposures of medications (such as oral contraceptive agents) which interact with enzymes and transporters regulated by PXR. In summary, nafcillin, dicloxacillin, cephradine, tetracycline, sulfixoxazole, erythromycin, clindamycin, and griseofulvin exhibit a clear propensity to induce CYP3A4 and warrant further clinical investigation.

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In Vitro and Pharmacophore-Based Discovery of Novel hPEPT1 Inhibitors

Abstract: This study demonstrates the potential of combining computational and in vitro approaches to determine the affinity of compounds for hPEPT1 and, in turn, provides insights into key molecular interactions with this transporter.

Cited by 61 publications

References 24 publications

Clinical implications of pharmacogenomics of statin treatment

Clinical implications of pharmacogenomics of statin treatment

Bacterial Peptide Recognition and Immune Activation Facilitated by Human Peptide Transporter PEPT2

A Comprehensive in Vitro and in Silico Analysis of Antibiotics That Activate Pregnane X Receptor and Induce CYP3A4 in Liver and Intestine

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