scholarly journals Effects of arginine on intestinal epithelial cell integrity and nutrient uptake

2016 ◽  
Vol 116 (10) ◽  
pp. 1675-1681 ◽  
Author(s):  
Mi Xia ◽  
Lulu Ye ◽  
Qihang Hou ◽  
Qinghua Yu
Keyword(s):  
Amino Acid ◽  
Epithelial Cell ◽  
Nutrient Uptake ◽  
Intestinal Epithelial Cell ◽  
Amino Acid Transporter ◽  
Acid Uptake ◽  
Intestinal Epithelial ◽  
Physiological Level ◽  
Acid Transporter ◽  
Arginine Concentration

AbstractArginine is a multifaceted amino acid that is critical to the normal physiology of the gastrointestinal tract. Oral arginine administration has been shown to improve mucosal recovery following intestinal injury. The present study investigated the influence of extracellular arginine concentrations on epithelial cell barrier regulation and nutrition uptake by porcine small intestinal epithelial cell line (IPEC-J2). The results show that reducing arginine concentration from 0·7 to 0·2 mm did not affect the transepithelial electrical resistance value, tight-junction proteins (claudin-1, occludin, E-cadherin), phosphorylated extracellular signal-regulated protein kinases (p-ERK) and mucin-1 expression. Furthermore, reducing arginine concentration stimulated greater expression of cationic amino acid transporter (CAT1), excitatory amino acid transporter (EAAT3) and alanine/serine/cysteine transporter (ASCT1) mRNA by IPEC-J2 cells, which was verified by elevated efficiency of amino acid uptake. Glucose consumption by IPEC-J2 cells treated with 0·2 mm-arginine remained at the same physiological level to guarantee energy supply and to maintain the cell barrier. This experiment implied that reducing arginine concentration is feasible in IPEC-J2 cells guaranteed by nutrient uptake and cell barrier function.

scholarly journals Gallic acid affects intestinal-epithelial-cell integrity and selected amino-acid uptake in porcine in vitro and ex vivo permeability models

2020 ◽  
pp. 1-9
Author(s):  
Marco Tretola ◽  
Giuseppe Bee ◽  
Paolo Silacci
Keyword(s):  
Amino Acid ◽  
Epithelial Cell ◽  
Protein Expression ◽  
Gallic Acid ◽  
Intestinal Epithelial Cell ◽  
Ex Vivo ◽  
Amino Acid Transporter ◽  
Intestinal Epithelial ◽  
Cell Integrity

Abstract Gallic acid (GA) is widely used as a dietary supplement due to several health-promoting effects, although its effects on intestinal-epithelial-cell integrity and transport remain mostly unknown. The present study aims to clarify the effects of GA on tight junctions and intestinal nutrient uptake through in vitro and ex vivo models. Both intestinal porcine enterocyte cell line-J2 cells and porcine middle-jejunum segments were treated with 5 (T5), 25 (T25) and 50 (T50) µm GA and mounted in Ussing chambers to determine transepithelial resistance (TEER), claudin-1 (CLDN1), occludin (OCLN), zonula occludens-1 (ZO-1) protein (in tissues and cells) and mRNA (in cells) expression. In addition, uptake of l-glutamate (l-Glut), l-arginine (l-Arg), l-lysine (l-Lys) and l-methionine (l-Meth) together with cationic-amino-acid transporter-1 (CAT-1) and excitatory-amino-acid transporter-3 (EAAT3) expression was evaluated. No apoptosis was observed in GA-treated cells, but TEER and CLDN1 protein abundance was lower with T50 compared with untreated cells. l-Arg and l-Lys uptake was greater with T5 than with T25 and T50. Ex vivo, T50 decreased the TEER values and the protein levels of CLDN1, OCLN and ZO-1, whereas T5 and T25 only decreased CLDN1 protein expression compared with untreated tissues. Moreover, T25 increased l-Glut and l-Arg uptake, the latter confirmed by an increased protein expression of CAT-1. GA influences intestinal uptake of the tested cationic amino acids at low concentrations and decreases the intestinal-cell barrier function at high concentrations. Similarities were observed between in vitro and ex vivo, but different treatment times and structures must be considered.

scholarly journals Identification and Characterization of Inhibitors of a Neutral Amino Acid Transporter, SLC6A19, Using Two Functional Cell-Based Assays

2018 ◽  
Vol 24 (2) ◽  
pp. 111-120 ◽  
Author(s):  
Sanjay J. Danthi ◽  
Beirong Liang ◽  
Oanh Smicker ◽  
Benjamin Coupland ◽  
Jill Gregory ◽  
...  
Keyword(s):  
Amino Acid ◽  
High Throughput Screening ◽  
Amino Acid Transporter ◽  
Neutral Amino Acid ◽  
Imaging Plate ◽  
Acid Uptake ◽  
Functional Assays ◽  
Neutral Amino Acid Transporter ◽  
Acid Transporter ◽  
Pharmacologically Active

SLC6A19 (B0AT1) is a neutral amino acid transporter, the loss of function of which results in Hartnup disease. SLC6A19 is also believed to have an important role in amino acid homeostasis, diabetes, and weight control. A small-molecule inhibitor of human SLC6A19 (hSLC6A19) was identified using two functional cell-based assays: a fluorescence imaging plate reader (FLIPR) membrane potential (FMP) assay and a stable isotope-labeled neutral amino acid uptake assay. A diverse collection of 3440 pharmacologically active compounds from the Microsource Spectrum and Tocriscreen collections were tested at 10 µM in both assays using MDCK cells stably expressing hSLC6A19 and its obligatory subunit, TMEM27. Compounds that inhibited SLC6A19 activity in both assays were further confirmed for activity and selectivity and characterized for potency in functional assays against hSLC6A19 and related transporters. A single compound, cinromide, was found to robustly, selectively, and reproducibly inhibit SLC6A19 in all functional assays. Structurally related analogs of cinromide were tested to demonstrate structure–activity relationship (SAR). The assays described here are suitable for carrying out high-throughput screening campaigns to identify modulators of SLC6A19.

Intracellular regulation of intestinal folate uptake: studies with cultured IEC-6 epithelial cells

1997 ◽  
Vol 272 (2) ◽  
pp. C729-C736 ◽  
Author(s):  
H. M. Said ◽  
T. Y. Ma ◽  
A. Ortiz ◽  
A. Tapia ◽  
C. K. Valerio
Keyword(s):  
Small Intestine ◽  
Folic Acid ◽  
Protein Kinase ◽  
Epithelial Cell ◽  
Intestinal Epithelial Cell ◽  
Acid Uptake ◽  
Maximal Velocity ◽  
Intestinal Epithelial ◽  
Intracellular Regulation ◽  
Uptake Process

Although the mechanism of folate uptake in the small intestine has been well characterized, very little is known about the intracellular regulation of the uptake process. Using mature confluent monolayers of the intestinal epithelial cell line IEC-6 as an in vitro intestinal epithelial cell model, we have found the uptake of folic acid to be similar to that of the native small intestine in that it is 1 ) temperature, energy, and pH dependent, 2) Na+ independent, 3) inhibited by structural analogs and anion transport inhibitors, and 4) saturable as a function of substrate concentration [apparent Michaelis constant (Km) = 0.45 +/- 0.06 microM; maximal velocity (Vmax) = 3.08 +/- 0.14 pmol x mg protein(-1) x 5 min(-1)]. Furthermore, IEC-6 cells were found by Northern blot analysis to lack the expression of the membrane folate-binding protein. Pretreatment of IEC-6 monolayers with specific protein tyrosine kinase (PTK) inhibitors genistein and tyrphostin A25 caused a significant inhibition in folic acid uptake. On the other hand, their negative controls, genistin and tyrphostin A1, respectively, had no effect. The inhibitory effect of genistein was mediated through inhibition in the Vmax of the folate uptake process with no change in the apparent Km. Pretreatment of IEC-6 monolayers with compounds that increase intracellular adenosine 3',5'-cyclic monophosphate (cAMP) level (e.g., dibutyryl cAMP) also resulted in a significant (though modest) inhibition in folic acid uptake; however, specific inhibitors of protein kinase A did not affect the uptake process. Specific modulators of protein kinase C and Ca2+/calmodulin-mediated pathways did not significantly affect folic acid uptake. These results demonstrate the suitability of IEC-6 monolayers as an intestinal epithelial model to study folate transport and demonstrate for the first time that uptake of folic acid is regulated by a PTK- and a cAMP-mediated pathway.

scholarly journals D-Cycloserine transport in human intestinal epithelial (Caco-2) cells: mediation by a H + -coupled amino acid transporter

1995 ◽  
Vol 115 (5) ◽  
pp. 761-766 ◽  
Author(s):  
David T. Thwaites ◽  
Gillian Armstrong ◽  
Barry H. Hirst ◽  
Nicholas L. Simmons
Keyword(s):  
Amino Acid ◽  
Amino Acid Transporter ◽  
Intestinal Epithelial ◽  
Acid Transporter

A villous cell-derived inhibitor of intestinal cell proliferation

1981 ◽  
Vol 241 (6) ◽  
pp. G520-G527
Author(s):  
R. J. May ◽  
A. Quaroni ◽  
K. Kirsch ◽  
K. J. Isselbacher
Keyword(s):  
Epithelial Cell ◽  
Dna Synthesis ◽  
Cell Lines ◽  
Intestinal Epithelial Cell ◽  
Amino Acid Uptake ◽  
Intestinal Cell ◽  
Epithelial Cell Line ◽  
Acid Uptake ◽  
Intestinal Epithelial

To test the hypothesis that the intestinal villous cell synthesizes a mitotic inhibitor that is specific for crypt cells, we have partially purified an extract from rat intestinal villous cells (VCE) and have demonstrated that it strongly and reversibly inhibits cell division and DNA synthesis in an intestinal epithelial cell line (IEC-6 cells). VCE produced a 60--70% inhibition of [3H]thymidine incorporation into DNA and a similar magnitude of inhibition of labeling of nuclei in autoradiographic studies. This inhibition was not associated with cytotoxicity as assessed by the effect of VCE on 51Cr release, hexose or amino acid uptake, and protein synthesis. VCE appears specific for IEC-6 cells because it did not affect DNA synthesis in 10 other cell lines, and extracts derived from other cell lines and from colonic mucosa did not affect DNA synthesis in IEC-6 cells. VCE may represent a villous cell factor involved in the control of intestinal epithelial cell turnover in vivo.

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