Transport Mechanisms of Polymannuronic Acid and Polyguluronic Acid Across Caco-2 Cell Monolayers

Abstract

Detailed knowledge of the intestinal transport of polymannuronic acid (PM) and polyguluronic acid (PG) is critical for understanding their biological activities. To investigate the transport in the gastrointestinal tract, PM and PG were chemically modified with tyramine and conjugated with fluorescein isothiocyanate (FITC) to synthesize FITC-PM (F-PM) and FITC-PG (F-PG) successfully. The transport mechanisms of F-PM and F-PG across the intestinal epithelial cell monolayers (Caco-2 cell monolayers) were then investigated. The results demonstrated that the transport of F-PM and F-PG into epithelial cells was time- and energy-dependent, which was mediated by the macropinocytosis pathway and the clathrin- and caveolae (or lipid raft)-mediated endocytic pathway. The transport process of F-PM and F-PG in Caco-2 cells depended on the acidification of endosomes and involved lysosomes. Tubulin mediated the transport of F-PM, but not of F-PG. Moreover, the absorption enhancer chitosan (CS) promoted the transport of F-PM and F-PG, increasing the apparent permeability coefficient (Papp) by 1.9-fold and 2.6-fold, respectively, by reversibly opening the tight junction (TJ). In summary, this study provided a comprehensive understanding of the transport of PM and PG in the small intestinal epithelial cells, which will provide a theoretical basis for the development of PM and PG with good intestinal absorption.

Hydroxycinnamic acid derivatives effect on hypercholesterolemia, comparison with ezetimibe: Permeability assays and FTIR spectroscopy on Caco-2 ​cell line

“…The Caco-2 ​cell monolayer model is widely used to mimic the absorption and transport of drugs across the intestinal epithelial layer ( Wang et al., 2020 ). The permeability of hydroxycinnamic acid derivatives and EZ in presence of cholesterol was studied by using the Caco-2 ​cell line differentiated as a monolayer, in a Transwell system.…”

Fluorescent Labeling of Polymannuronic Acid and Its Distribution in Mice by Tail Vein Injection

“…After loading 10 μL of sample into each hole, the voltage was set at 60 V, and electrophoresis was timed for 80 min. The gels were observed with a gel imager (Bio-RAD, Hercules, CA, USA) [ 12 ].…”

“…Owing to a lack of chromophore and light-absorbing groups in PM, other biological components easily interfere with the detection of PM concentrations in vivo, which makes it difficult to establish an effective analytical method. In our previous study, PM was labeled with fluorescein isothiocyanate (FITC) to synthesize FITC-PM, detected the cytotoxicity by MTT, and then the PM-transport mechanism was studied using Caco-2 cell monolayer model [ 12 ]. The results of the study provided the first detailed information on the mechanisms of PM transport across intestinal epithelial cells in vitro: the PM had no measurable cytotoxicity, the transportation of PM in Caco-2 cells was a time-dependent and energy-dependent process with carrier saturation and efflux.…”

“…Our group previously found that PM can be absorbed and transported by intestinal epithelial cells via endocytosis. These studies were limited in vitro experiments, and PM shows a very low oral transport rate (at 50 μg/mL, the transport rate of PM is only 1.71%), which makes it difficult to achieve an effective blood concentration [ 12 ]. There have been no studies on the distribution or pharmacokinetics of PM in vivo conducted so far.…”

Nanoemulsions of Hydroxysafflor Yellow A for Enhanced Brain Delivery in Cerebral Ischemia Reperfusion-injured mice: Physicochemical and In Vivo Performances

“…Results by Liu et al showed that the stability constant of the complex formed with HPCD was enhanced after avanones are complexed with cyclodextrin [26] . Chitosan is a cationic polysaccharide with the function of adhering mucous membrane, which can reversibly open Caco-2 cells to promote drug absorption [27] , Ma et al prepared the HYA-CS complex, the bioavailability of HYA was increased by 4.76 times [28] . Lv et al also found that HYA is a Pglycoprotein substrate analog, which is easily excreted by P-glycoprotein in the intestinal tract, and leads to a strong bile e ux effect and low absorption [18] .…”