Oligopeptide transport in rat lung alveolar epithelial cells is mediated by Pept2
HJ Gukasyan, T Uchiyama, KJ Kim, C Ehrhardt… - Pharmaceutical …, 2017 - Springer
Pharmaceutical research, 2017•Springer
Purpose Studies were conducted in primary cultured rat alveolar epithelial cell monolayers
to characterize peptide transporter expression and function. Methods Freshly isolated rat
lung alveolar epithelial cells were purified and cultured on permeable support with and
without keratinocyte growth factor (KGF). Messenger RNA and protein expression of Pept1
and Pept2 in alveolar epithelial type I-and type II-like cell monolayers (±KGF, resp.) were
examined by RT-PCR and Western blotting. 3 H–Glycyl-sarcosine (3 H–gly-sar) …
to characterize peptide transporter expression and function. Methods Freshly isolated rat
lung alveolar epithelial cells were purified and cultured on permeable support with and
without keratinocyte growth factor (KGF). Messenger RNA and protein expression of Pept1
and Pept2 in alveolar epithelial type I-and type II-like cell monolayers (±KGF, resp.) were
examined by RT-PCR and Western blotting. 3 H–Glycyl-sarcosine (3 H–gly-sar) …
Purpose
Studies were conducted in primary cultured rat alveolar epithelial cell monolayers to characterize peptide transporter expression and function.
Methods
Freshly isolated rat lung alveolar epithelial cells were purified and cultured on permeable support with and without keratinocyte growth factor (KGF). Messenger RNA and protein expression of Pept1 and Pept2 in alveolar epithelial type I- and type II-like cell monolayers (±KGF, resp.) were examined by RT-PCR and Western blotting. 3H–Glycyl-sarcosine (3H–gly-sar) transmonolayer flux and intracellular accumulation were evaluated in both cell types.
Results
RT-PCR showed expression of Pept2, but not Pept1, mRNA in both cell types. Western blot analysis revealed presence of Pept2 protein in type II-like cells, and less in type I-like cells. Bi-directional transmonolayer 3H–gly-sar flux lacked asymmetry in transport in both types of cells. Uptake of 3H–gly-sar from apical fluid of type II-like cells was 7-fold greater than that from basolateral fluid, while no significant differences were observed from apical vs. basolateral fluid of type I-like cells.
Conclusions
This study confirms the absence of Pept1 from rat lung alveolar epithelium in vitro. Functional Pept2 expression in type II-like cell monolayers suggests its involvement in oligopeptide lung disposition, and offers rationale for therapeutic development of di/tripeptides, peptidomimetics employing pulmonary drug delivery.
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