Development, Characterization and Application of a Novel Mouse Line Humanized for the Intestinal Peptide Transporter PepT1.

Transporter;PepT1 (SLC15a1);Humanized mice;Cefadroxil;Pharmacokinetics;prediction;Pharmacy and Pharmacology;Health Sciences;Science;Pharmaceutical Sciences

Hu, YongjunAmidon, Gordon L. ;

University of Michigan

关键词: Transporter;    PepT1 (SLC15a1);    Humanized mice;    Cefadroxil;    Pharmacokinetics;    prediction;    Pharmacy and Pharmacology;    Health Sciences;    Science;    Pharmaceutical Sciences;   

Others  :  https://deepblue.lib.umich.edu/bitstream/handle/2027.42/113491/yongjun_1.pdf?sequence=1&isAllowed=y

瑞士|英语

来源: The Illinois Digital Environment for Access to Learning and Scholarship

【 摘 要 】

Transporter PepT1 is abundantly expressed on the apical side of small intestinal enterocytes and has major responsibility for the intestinal absorption of peptides and peptide-like drugs with a significant species difference in the affinity and capacity. Therefore, a humanized PepT1 mouse model (huPepT1) was established. The mRNA and protein profiles indicated huPepT1 mice had substantial but lower levels than wildtype animals in their expression of PepT1 in small intestine. However, colonic expression of PepT1 was greater in huPepT1 mice. In situ intestinal perfusion studies revealed the permeability of GlySar and cefadroxil were similar, but lower, in huPepT1 mice as compared to wildtype animals. In colon, the permeability was greater in huPepT1 mice. Specificity studies demonstrated GlySar and cefadroxil permeability was largely dependent upon PepT1 function. However, a species difference was observed in the jejunal flux kinetics of GlySar and cefadroxil, where Km values for PepT1 were 2-fold lower in humanized than wildtype mice. In vivo studies indicated the functional activity of PepT1 was fully restored in humanized mice. After intravenous bolus doses of cefadroxil, virtually superimposable plasma concentration-time profiles were observed between wildtype and huPepT1 mice, and no differences were noted in CL, Vss, and T1/2 between these two genotypes. However, the Cmax, Tmax and AUC of humanized mice were 2-fold smaller than wildtype animals following oral dose escalation; T1/2 was unchanged. The slopes of partial cumulative AUC vs. time plots demonstrated the absorption rate of cefadroxil was 2-fold greater in wildtype mice, and the AUC was dose-proportional in these animals. In contrast, a less than proportional increase was observed in AUC with increasing oral doses of cefadroxil in humanized mice. Finally, the AUC0-120 or Cmax of cefadroxil vs. dose profiles showed huPepT1 mice and humans were more similar visually than that of wildtype mice and humans. In concluding, this study presents for the first time the generation and characterization of a mouse model humanized for PepT1.This animal model should provide a valuable tool in probing the role, relevance and regulation of PepT1, and in predicting the transport kinetics in humans.