Mechanistic Insights into PEPT1-Mediated Transport of a Novel Antiepileptic, NP-647

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• 作者：Kailas S. Khomane ; Prajwal P. Nandekar ; Banrida Wahlang ; Pravin Bagul ; Naeem Shaikh ; Yogesh B. Pawar ; Chhuttan Lal Meena ; Abhay T. Sangamwar ; Rahul Jain ; K. Tikoo ; Arvind K. Bansal
• 刊名：Molecular Pharmaceutics
• 出版年：2012
• 出版时间：September 4, 2012
• 年：2012
• 卷：9
• 期：9
• 页码：2458-2468
• 全文大小：549K
• 年卷期：v.9,no.9(September 4, 2012)
• ISSN：1543-8392

文摘

The present study, in general, is aimed to uncover the properties of the transport mechanism or mechanisms responsible for the uptake of NP-647 into Caco-2 cells and, in particular, to understand whether it is a substrate for the intestinal oligopeptide transporter, PEPT1 (SLC15A1). NP-647 showed a carrier-mediated, saturable transport with Michaelis鈥揗enten parameters K_m = 1.2 mM and V_max = 2.2 渭M/min. The effect of pH, sodium ion (Na⁺), glycylsarcosine and amoxicillin (substrates of PEPT1), and sodium azide (Na⁺/K⁺-ATPase inhibitor) on the flux rate of NP-647 was determined. Molecular docking and molecular dynamics simulation studies were carried out to investigate molecular interactions of NP-647 with transporter using homology model of human PEPT1. The permeability coefficient (P_appCaco-2) of NP-647 (32.5 脳 10^鈥? cm/s) was found to be four times higher than that of TRH. Results indicate that NP-647 is transported into Caco-2 cells by means of a carrier-mediated, proton-dependent mechanism that is inhibited by Gly-Sar and amoxicillin. In turn, NP-647 also inhibits the uptake of Gly-Sar into Caco-2 cells and, together, this evidence suggests that PEPT1 is involved in the process. Docking and molecular dynamics simulation studies indicate high affinity of NP-647 toward PEPT1 binding site as compared to TRH. High permeability of NP-647 over TRH is attributed to its increased hydrophobicity which increases its affinity toward PEPT1 by interacting with the hydrophobic pocket of the transporter through hydrophobic forces.

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<a id="authors" href="http://pubs.acs.org/action/doSearch?action=search&searchText=TRH+analogues&qsSearchArea=searchText">TRH analogues; <a id="authors" href="http://pubs.acs.org/action/doSearch?action=search&searchText=Caco%5C-2+cells&qsSearchArea=searchText">Caco-2 cells; <a id="authors" href="http://pubs.acs.org/action/doSearch?action=search&searchText=peptide+transporters&qsSearchArea=searchText">peptide transporters; <a id="authors" href="http://pubs.acs.org/action/doSearch?action=search&searchText=PEPT1+%5C%28SLC15A1%5C%29&qsSearchArea=searchText">PEPT1 (SLC15A1); <a id="authors" href="http://pubs.acs.org/action/doSearch?action=search&searchText=intestinal+oligopeptide+transporter&qsSearchArea=searchText">intestinal oligopeptide transporter; <a id="authors" href="http://pubs.acs.org/action/doSearch?action=search&searchText=homology+modeling&qsSearchArea=searchText">homology modeling; <a id="authors" href="http://pubs.acs.org/action/doSearch?action=search&searchText=docking+studies&qsSearchArea=searchText">docking studies; <a id="authors" href="http://pubs.acs.org/action/doSearch?action=search&searchText=molecular+dynamics+simulation&qsSearchArea=searchText">molecular dynamics simulation