1. Transepithelial transport across Caco-2 cell monolayers of antihypertensive egg-derived peptides. PepT1-mediated flux of Tyr-Pro-Ile
Marta Miguel, Alberto Dávalos, María A Manso, Gema de la Peña, Miguel A Lasunción, Rosina López-Fandiño Mol Nutr Food Res. 2008 Dec;52(12):1507-13. doi: 10.1002/mnfr.200700503.
This paper examines the in vitro transepithelial transport of antihypertensive peptides derived from egg proteins using Caco-2 cell monolayers. Ovokinin (FRADHPFL) was absorbed intact through the Caco-2 cell epithelium, although it was also susceptible to the action of brush-border aminopeptidases that yielded shorter fragments prior to their transport. The tripeptide YPI was resistant to cellular peptidases and transported through the monolayer, what suggests that the reduction in systemic blood pressure caused by this peptide may be mediated by effects at tissue level. Its pathway for transepithelial absorption was examined using inhibitors of the different mechanisms for oligopeptide transport in the intestinal tract. The main route involved in the transepithelial flux of YPI is probably the peptide H(+)-coupled transporter PepT1. These results highlight the potential of antihypertensive peptides to be used in the formulation of functional foods.
2. Hydrolysis and transepithelial transport of two corn gluten derived bioactive peptides in human Caco-2 cell monolayers
Long Ding, Liying Wang, Ting Zhang, Zhipeng Yu, Jingbo Liu Food Res Int. 2018 Apr;106:475-480. doi: 10.1016/j.foodres.2017.12.080. Epub 2018 Jan 3.
The objective of this paper was to investigate the transepithelial transport of two novel corn gluten-derived antioxidant peptides, YFCLT and GLLLPH, using Caco-2 cell monolayers. Results showed that both of YFCLT and GLLLPH could transport in intact form across Caco-2 cell monolayers with apparent permeability coefficient (Papp) values of (1.10±0.16)×10-7cm/s and (1.98±0.23)×10-7cm/s, respectively. However, it was found that the two peptides were susceptible and easily hydrolyzed by brush border membrane peptidases. In the presence of diprotin A, an inhibitor of dipeptidyl peptidase IV (DPPIV), the hydrolysis of YFCLT and GLLLPH decreased and their permeabilities increased significantly compared to control group (P0.05), suggesting that the transport of YFCLT and GLLLPH across Caco-2 cell monolayers was not mediated by PepT1. However, it was found that cytochalasin d, a tight junctions (TJs) disruptor, increased the permeability significantly (P<0.05). While wortmannin, a transcytosis inhibitor, and sodium azide, an ATP synthesis inhibitor, both decreased the permeability significantly (P<0.05). It indicated that the TJs-mediated paracellular pathway and energy-dependent transcytosis were involved in the transport of YFCLT and GLLLPH across Caco-2 cell monolayers.
3. Digestion and absorption of an egg white ACE-inhibitory peptide in human intestinal Caco-2 cell monolayers
Long Ding, Liying Wang, Zhipeng Yu, Ting Zhang, Jingbo Liu Int J Food Sci Nutr. 2016;67(2):111-6. doi: 10.3109/09637486.2016.1144722. Epub 2016 Feb 16.
The objective of this study was to investigate the digestion and absorption of egg white-derived angiotensin I-converting enzyme (ACE)-inhibitory peptide TNGIIR in human intestinal Caco-2 cell monolayers. Results showed that the digestion of TNGIIR to simulated gastrointestinal enzymes and brush border membrane peptidases were 5.87% ± 1.92% and 17.17% ± 0.64%, respectively (p < 0.05). The apparent permeability coefficients (P(app)) of TNGIIR from the apical to basolateral side in Caco-2 cell monolayers was determined to be (4.92 ± 0.40) × 10(-6) cm/s, indicating that TNGIIR can transport across Caco-2 cell monolayers in intact form. In addition, only cytochalasin D, a disruptor of tight junctions (TJs), changed TNGIIR transport rate significantly (p < 0.05), suggesting that the main transport route for TNGIIR across Caco-2 cell monolayers was paracellular pathway via TJs.
