Published ahead of print on December 30, 2004, doi:10.1165/rcmb.2004-0322OC Am. J. Respir. Cell Mol. Biol., Volume 32, Number 4, April 2005, 319-325 A more recent version of this article appeared on April 1, 2005
Submitted on October 8, 2004 Functional Characterization of the Peptide Transporter PEPT2 in Primary Human Lung EpitheliumPraveen M Bahadduri1,1 Department of Pharmaceutical Sciences, University of Maryland, Baltimore, MD, USA, 2 Department of Pharmacology, Program in Pharmacogenomics, The Ohio State University, Columbus, OH, USA, 3 Department of Pharmacy and Internal Medicine, The Ohio State University, Columbus, OH, USA * To whom correspondence should be addressed. E-mail: pswaan{at}rx.umaryland.edu.
This study characterizes the expression and function of the peptide transporter hPepT2 (SLC15A2) in differentiated primary cultures of human upper airway lung epithelia obtained from six human donors. Genotype analysis of a SNP in exon 15 of hPepT2 genotypes in six donors revealed an expected distribution of the two main variants present at similar frequency (2 AA homozygotes, 2 BB homozygotes, and 2 AB heterozygotes). Real-time PCR analysis of the hPepT2 mRNA message revealed no significant differences amongst genotypes. hPEPT2 was expressed on the apical membrane in all donor specimens, demonstrated by cell surface biotinylation and Western analysis (104kD). We then compared transepithelial transport of the prototypical substrate 3H-glycylsarcosine in all donor cultures in the absence and presence of known inhibitors of hPEPT2 to ascertain the phenotype of functionally expressed hPepT2 in the upper airway epithelium. An array of inhibitors included dipeptides,
This article has been cited by other articles:
|
|
||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||||
-lactam antibiotics, bestatin, and ACE inhibitors. hPEPT2 exhibited saturable Michaelis-Menten type kinetic parameters for GlySar, corroborating previously reported values for KT and Jmax. Donor-to-donor variation of transport for different substrates did not correlate with hPepT2 haplotypes in this sample cohort. These findings demonstrate functional hPEPT2 transporter expression in primary cultures of human lung epithelial cells. hPEPT2-mediated transport could serve as a strategy for noninvasive systemic delivery of peptides and peptidomimetics drugs.
