L-Tryptophan Differentially Regulated Glucose and Amino Acid Transporters in the Small Intestine of Rat Challenged with Lipopolysaccharide

Abstract

Tryptophan (Trp) has been shown to improve the growth and gut function of weaned piglets. Whether the growth-promoting effect of Trp is due to the improvement in nutrient transport and absorption during weaning or under conditions of inflammation has not been fully characterized. The objective of this study was to determine the effects of Trp on lipopolysaccharide (LPS)-induced changes in glucose and amino acid (AA) transport in the rat jejunum. Twenty-four 7-week-old Sprague Dawley rats were randomly divided into one of three groups: control, LPS, and Trp + LPS. Rats were supplemented with 0 or 0.1 mg Trp per gram body weight/d in drinking water for 7 days and were intraperitoneally injected with LPS (5 mg/kg BW) on day 8. After 24 h, rats were sacrificed, and jejunum samples were isolated for the analysis of glucose and AA transport using an Ussing chamber and the expression of glucose and AA transporters. The results showed that Trp alleviated the LPS-induced increase in jejunal permeability (p < 0.05) and decrease in changes in the short-circuit current of glucose, arginine, glutamine, glutamate, glycine, histidine, leucine, lysine, taurine, threonine, and Trp (p < 0.05). Trp reversed (p < 0.05) the LPS-induced downregulation of expression of the glucose transporter SGLT1 and AA transporters solute carrier family 38 member 2 (SNAT2) and solute carrier family 7 member 8 (LAT2), as well as ATPase Na+/K+ transporting subunit alpha 2 (ATP1A2). However, Trp increased (p < 0.01) the LPS-induced upregulation of acidic AA transporter solute carrier family 1 member 1 (EAAT3) expression. The above findings may help to develop nutritional interventions for the differential targeting of gut nutrient transporters, aiming to improve gut function and health in the presence of inflammation in both humans and animals.

Isolation and identification of active components from Grifola frondosa and its anti‐EV71 virus effect

“…It participates in and regulates the synthesis and metabolic network of various proteins in the body, and has biological activities with respect to lowering blood pressure, anti-depression effects and treating insomnia. 31,32 Therefore, L-tryptophan in the present study showed high use value for antiviral activity. The active compound L-tryptophan might inhibit the replication of EV71 virus, and play a protective role in cells, reducing the apoptosis caused by virus infection cells.…”

“…In addition, tryptophan is also one of the eight essential amino acids in the human body. It participates in and regulates the synthesis and metabolic network of various proteins in the body, and has biological activities with respect to lowering blood pressure, anti‐depression effects and treating insomnia 31,32 . Therefore, l ‐tryptophan in the present study showed high use value for antiviral activity.…”

Cinnamic Acid, Perillic Acid, and Tryptophan Metabolites Differentially Regulate Ion Transport and Serotonin Metabolism and Signaling in the Mouse Ileum In Vitro

“…Phytochemicals and Trp metabolites have been shown to improve gut function and homeostasis, and these health-promoting effects may be partially due to their regulation of gut 5-HT metabolism and signaling [ 35 , 36 ]. Gut barrier function is important not only for defense against luminal pathogens but also for nutrient absorption and electrolyte balance [ 37 ]. Our current study suggested that VMA reduced the short-circuit current, and 100 μM CGA and PA had a tendency to reduce the short-circuit current of the ileum.…”

Effects of Dietary Tryptophan on Growth Performance, Plasma Parameters, and Internal Organs of 1–28-Day-Old Sichuan White Geese

“…Our results suggest that Trp promotes the relative weights of the proximal intestine, particularly the duodenum and jejunum; however, the mechanism requires further investigation. Studies have shown that Trp activates mammalian rapamycin complex 1 and increases the mRNA levels of amino acid transporters (e.g., SLC6A19, SLC6A14, and ATP1A1) ( Wang et al , 2015 ; Wang et al , 2022 ). Moreover, dietary Trp increases the abundance of tight junction proteins, ZO-1, ZO-3, and claudin-1, in the jejunum and duodenum ( Liang et al , 2018 ).…”