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Updated: Jul 19, 2025

Mixed Primary Cultures of Murine Small Intestine Intended for the Study of Gut Hormone Secretion and Live Cell Imaging of Enteroendocrine Cells
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Transepithelial Transport of the Bifunctional Peptide IPYWTY Indirectly Induced Insulin Release Mediated by Active

Mingkai Zhang1, Ling Zhu1, Hui Zhang1

  • 1National Engineering Research Center for Functional Food, Collaborative Innovation Center of Food Safety and Quality Control in Jiangsu Province, School of Food Science and Technology, Jiangnan University, 1800 Lihu Road, Wuxi 214122, China.

Journal of Agricultural and Food Chemistry
|August 17, 2023
PubMed

There is currently no appropriate cell model suitable for evaluating the insulinotropic effects of DPP-4 inhibitory peptides (DPP-4IPs) mediated by active glucagon-like peptide-17-36 (active GLP-1). The study aims to evaluate the transepithelial transport of IPYWTY on its in situ insulinotropic effects by using a 2D and dual-layered coculture cell model that consists of Caco-2 and NCI-H716 cells on the apical (AP) side and β-TC-6 cells on the basolateral (BL) side. During transportation, IPYWTY was absorbed in its intact form through PepT1 and paracellular transport. Meanwhile, it was degraded to several peptide fragments, including PYWTY, YWTY, WTY, and IPY, which decreased its in situ DPP-4 inhibitory activity. IPYWTY does not directly stimulate insulin release in β-TC-6 cells, while it increased the active GLP-1 level from 76.57 ± 15.16 to 95.63 ± 1.99 pM (1.25 times) in NCI-H716 cells. Interestingly, IPYWTY indirectly increased insulin levels from 426.91 ± 6.07 to 573.94 ± 2.97 μIU/mL (1.34 times) in the 2D and dual-layered coculture cell model for its dual function of stimulating active GLP-1 secretion and DPP-4 inhibition. These results suggested that the 2D and dual-layered coculture cell model is an alternative strategy for effectively evaluating the insulinotropic effects of DPP-4IPs mediated by active GLP-1.

Keywords:
DPP-4GLP-1insulinpea peptidetransepithelial transport

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