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In this phase 2 trial in patients with metabolic dysfunction–associated steatohepatitis and moderate or severe fibrosis, tirzepatide was more effective than placebo with respect to resolution of MASH without worsening of fibrosis.

BackgroundCirculating endotoxin (lipopolysaccharide, LPS) increases the gut paracellular permeability. We hypothesized that glucagon-like peptide-2 (GLP-2) acutely reduces LPS-related increased intestinal paracellular permeability by a mechanism unrelated to its intestinotrophic effect.MethodsWe assessed small intestinal paracellular permeability in vivo by measuring the appearance of intraduodenally perfused FITC-dextran 4000 (FD4) into the portal vein (PV) in rats 1–24 h after LPS treatment (5 mg/kg, ip). We also examined the effect of a stable GLP-2 analog teduglutide (TDG) on FD4 permeability.ResultsFD4 movement into the PV was increased 6 h, but not 1 or 3 h after LPS treatment, with increased PV GLP-2 levels and increased mRNA expressions of proinflammatory cytokines and proglucagon in the ileal mucosa. Co-treatment with a GLP-2 receptor antagonist enhanced PV FD4 concentrations. PV FD4 concentrations 24 h after LPS were higher than FD4 concentrations 6 h after LPS, reduced by exogenous GLP-2 treatment given 6 or 12 h after LPS treatment. FD4 uptake measured 6 h after LPS was reduced by TDG 3 or 6 h after LPS treatment. TDG-associated reduced FD4 uptake was reversed by the VPAC1 antagonist PG97-269 or L-NAME, not by EGF or IGF1 receptor inhibitors.ConclusionsSystemic LPS releases endogenous GLP-2, reducing LPS-related increased permeability. The therapeutic window of exogenous GLP-2 administration is at minimum within 6–12 h after LPS treatment. Exogenous GLP-2 treatment is of value in the prevention of increased paracellular permeability associated with endotoxemia.

Abstract Context Several cases of cholelithiasis and cholecystitis have been reported in patients treated with glucagon-like peptide 1 (GLP-1) receptor agonists (GLP-1RAs) and GLP-2 receptor agonists (GLP-2RAs), respectively. Thus, the effects of GLP-1 and GLP-2 on gallbladder motility have been investigated. We have provided an overview of the mechanisms regulating gallbladder motility and highlight novel findings on the effects of bile acids and glucagon-like peptides on gallbladder motility. Evidence Acquisition The articles included in the present review were identified using electronic literature searches. The search results were narrowed to data reporting the effects of bile acids and GLPs on gallbladder motility. Evidence Synthesis Bile acids negate the effect of postprandial cholecystokinin-mediated gallbladder contraction. Two bile acid receptors seem to be involved in this feedback mechanism, the transmembrane Takeda G protein-coupled receptor 5 (TGR5) and the nuclear farnesoid X receptor. Furthermore, activation of TGR5 in enteroendocrine L cells leads to release of GLP-1 and, possibly, GLP-2. Recent findings have pointed to the existence of a bile acid–TGR5–L cell–GLP-2 axis that serves to terminate meal-induced gallbladder contraction and thereby initiate gallbladder refilling. GLP-2 might play a dominant role in this axis by directly relaxing the gallbladder. Moreover, recent findings have suggested GLP-1RA treatment prolongs the refilling phase of the gallbladder. Conclusions GLP-2 receptor activation in rodents acutely increases the volume of the gallbladder, which might explain the risk of gallbladder diseases associated with GLP-2RA treatment observed in humans. GLP-1RA-induced prolongation of human gallbladder refilling may explain the gallbladder events observed in GLP-1RA clinical trials. Recent studies have suggested that bile acids and GLP-2 terminate cholecystokinin-induced gallbladder contraction, and GLP-1 receptor agonist treatment decelerates gallbladder refilling.

Glucagon-like peptide-2 (GLP-2) is a gut hormone that plays a pivotal role in regulating intestinal epithelial cell growth and function, making it a promising therapeutic agent for intestinal damage and bone-related diseases. Nonetheless, the therapeutic potential of GLP-2 is substantially diminished due to its inactivation by dipeptidyl peptidase 4 (DPP-4). In recent years, advancements have been made in developing dipeptidyl peptidase 4 (DPP-4) resistant GLP-2 analogues with an extended half-life. The murine model with extensive experimental bowel resection maintained on parenteral nutrition has been used for assessing the physiology and pharmacology of GLP-2, and for the preclinical validation of GLP-2 analogues. However, it possesses certain limitations, such as complex procedure, considerable variability, and time-consuming nature. Consequently, there is a pressing need for the development of a cell-based bioassay to assess GLP-2 analogues. Here, we successfully developed a mechanism-of-action (MOA)-reflective cell-based reporter gene assay (RGA), utilizing a stable HEK293 cell line expressing the GLP-2 receptor and a luciferase reporter gene. This innovative approach allows for precise quantification of the potency of GLP-2 analogues. The RGA demonstrated good accuracy, linearity, precision, and specificity, with potential applications in stability testing, drug screening, and therapeutic monitoring of GLP-2 analogues. Moreover, RNA sequencing reveals the multi-target regulatory effect of GLP-2 analogues. The establishment of this RGA provides a valuable tool for evaluating the potency of GLP-2 analogues and the screening of potential therapeutic drugs targeting to GLP-2 receptor.

Background: Glucagon-like peptide-2 (GLP-2) is a gut hormone secreted in response to nutrient intake and regulates lipid metabolism in the gut. The present study aims to elucidate the underlying mechanism of GLP-2 in stimulating gut lipid secretion in the fasted state by testing whether GLP-2 signals through the brain’s GLP-2 receptor and melanocortin 4 receptor (MC4R). Methods: Sprague-Dawley rats were implanted with a mesenteric lymph duct cannula for measuring gut lipid secretion and an intracerebroventricular cannula for infusion of a GLP-2R antagonist (GLP-2(11-33)), an MC4R antagonist (SHU9119), or saline as a control. The rat received a lipid infusion into the small intestine and a peritoneal injection of GLP-2 five hours later. Results: Brain administration of a GLP-2R antagonist or an MC4R antagonist attenuated the stimulatory effects of peripheral GLP-2 on lymph triglyceride output. These effects were associated with differential changes in the expression of key genes in jejunal endothelial cells, smooth muscle cells, and neuronal cells. Conclusions: These results support the involvement of central GLP-2R and MC4R in a neural pathway for GLP-2 to mobilize lipids stored in the gut during the post-absorptive state.

There is an urgent need for sustainable protein sources to meet rising global nutritional demands. Here, we show that a commercially scalable microbial lysate from Methylococcus capsulatus Bath (McB), used as a dietary protein, orchestrates host-diet-microbe interactions that protect against gastrointestinal inflammation. McB administration rapidly reshapes the gut microbiota and upregulates microbial fermentation pathways, while robustly increasing peripherally induced regulatory T cells (pTregs) across intestinal regions, independent of the microbiota. In contrast, McB-driven induction of tolerogenic Th17 cells requires a functional microbiota with intact fermentation capacity. In models of mucositis and colitis, McB preserves villus architecture, restores mucosal integrity, and reduces disease severity. Mechanistically, these effects depend on microbial fermentation and functional GLP-2 receptor signalling, yet are independent of endogenous GLP-2 secretion, indicating a fermentation-driven molecular mimicry of GLP-2R activation. Collectively, our findings position microbial lysates as a sustainable nutritional strategy that improves gastrointestinal health through defined immune and microbial pathways. Here, Yang-Jensen et al. demonstrate that a scalable microbial protein lysate from Methylococcus capsulatus Bath reshapes gut microbiota and T cells and, via fermentation-driven GLP-2 receptor mimicry, protects against gastrointestinal inflammation while providing sustainable protein nutrition

Background/Objectives: Dietary glucose is transported across the intestinal absorptive cell into the systemic circulation by the apically located Na+-dependent glucose transporter 1 (SGLT1, SLC5A1) and basally residing Na+-independent glucose transporter 2 (GLUT2, SLC2A2). Whilst recent experimental evidence has shown that sensing of sweet compounds by the gut-expressed sweet taste receptor T1R2–T1R3 and glucagon-like peptide-2 receptor signalling are components of the pathway controlling SGLT1 expression, little is known about the mechanisms involved in the regulation of GLUT2. In this study, we tested the hypothesis that T1R2–T1R3 and its downstream signalling pathway participate in the regulation of intestinal GLUT2. Methods: We used in vivo and in vitro approaches employing a weaning pig model, a heterologous expression assay, and knockout mice for elucidating the regulation of GLUT2 by luminal sugars. Results: A plant-based sweetener formulation included in piglets’ diet led to a marked increase in GLUT2 expression in piglets’ intestine, compared to controls. The sweeteners that do not activate pig T1R2–T1R3 failed to upregulate GLUT2. There was a significant increase in GLUT2 expression when the sweetener sucralose, which activates T1R2–T1R3, was included in the drinking water of wild-type mice. However, in knockout mice, in which the genes for the sweet receptor subunit T1R3 and the associated G-protein gustducin were deleted, there was no upregulation of GLUT2 expression in response to sucralose supplementation. There was a notable increase in GLUT2 expression in wild-type mice fed a high-carbohydrate diet compared to when maintained on a low-carbohydrate diet. However, in GLP-2 receptor knockout mice kept on the high-carbohydrate diet, there was no enhancement in GLUT2 expression. Conclusions: The experimental evidence suggests that luminal sweet sensing via T1R2–T1R3 and the enteroendocrine-derived GLP-2 are constituents of the regulatory pathway controlling GLUT2 expression.

Chronic cold exposure in mice increases metabolic demand and food intake; the gut correspondingly expands its absorptive surface area. Gut enteroendocrine cells produce peptide hormones including glucagon-like peptide-1 (GLP-1), GLP-2, and glucose-dependent insulinotropic polypeptide (GIP) in response to a meal to facilitate nutrient absorption and post-prandial metabolism. The requirement of GLP-1, GLP-2, and GIP receptor signaling for small intestinal adaptations to chronic cold stress has not been investigated. Here, we show that male and female wild-type, double incretin receptor knockout ( Glp1r -/- Gipr -/- ; DIRKO), and glucagon-like peptide double receptor knockout ( Glp1r -/- Glp2r -/- ; GLPDRKO) mice consume significantly more food over five weeks in cold (6⁰C) compared to thermoneutral (27 ⁰C; TN) conditions. Jejunal circumference, villi length, and crypt depth are significantly greater with cold-stress in WT and DIRKO mice, but not GLPDRKO mice, compared to TN controls. We show that the GLP-2R is required for jejunal villi length expansion upon cold stress despite significantly elevated plasma active GLP-1 levels. In line with this, GLPDRKO mice fail to gain body weight over the five-week experiment compared to WT controls. Therefore, while GLP-2R action is required for cold stress-induced jejunal villi lengthening, this adaptation is dispensable for body weight gain in the presence of GLP-1R signaling. Chronic cold stress in Glp1r -/- Gipr -/- , Glp1r -/- Glp2r -/- , and Glp2r -/- mice revealed distinct and overlapping roles for GLP-1R and GLP-2R in the expansion of the intestinal absorptive surface area expansion in response to chronic cold stress.

The work aiming to unravel the correlation between protein sequence and function in the absence of structural information can be highly rewarding. We present a new way of considering descriptors from the amino acids index database for modeling and predicting the fitness value of a polypeptide chain. This approach includes the following steps: (i) Calculating Q elementary numerical sequences (Ele_SEQ) depending on the encoding of the amino acid residues, (ii) determining an extended numerical sequence (Ext_SEQ) by concatenating the Q elementary numerical sequences, wherein at least one elementary numerical sequence is a protein spectrum obtained by applying fast Fourier transformation (FFT), and (iii) predicting a value of fitness for polypeptide variants (train and/or validation set). These new descriptors were tested on four sets of proteins of different lengths (GLP-2, TNF alpha, cytochrome P450, and epoxide hydrolase) and activities (cAMP activation, binding affinity, thermostability and enantioselectivity). We show that the use of multiple physicochemical descriptors coupled with the implementation of the FFT, taking into account the interactions between residues of amino acids within the protein sequence, could lead to very significant improvement in the quality of models and predictions. The choice of the descriptor or of the combination of descriptors and/or FFT is dependent on the couple protein/fitness. This approach can provide potential users with value added to existing mutant libraries where screening efforts have so far been unsuccessful in finding improved polypeptide mutants for useful applications.

Abstract Context Glucagon-like peptide-1 (GLP-1) receptor agonists (RAs) are established therapeutics for type 2 diabetes and obesity. Among other mechanisms, they slow gastric emptying and motility of the small intestine. This helps to limit postprandial glycemic excursions and reduce chylomicron formation and triglyceride absorption. Conversely, motility effects may have detrimental consequences, eg, retained gastric contents at endoscopy or general anesthesia, potentially complicated by pulmonary aspiration or bowel obstruction. Data Acquisition We searched the PubMed database for studies involving GLP-1RA therapy and adverse gastrointestinal/biliary events. Data Synthesis Retained gastric contents at the time of upper gastrointestinal endoscopy are found more frequently with GLP-1 RAs but rarely are associated with pulmonary aspiration. Well-justified recommendations for the periprocedural management of GLP-1RAs (eg, whether to withhold these medications and for how long) are compromised by limited evidence. Important aspects to be considered are (1) their long half-lives, (2) the capacity of GLP-1 receptor agonism to slow gastric emptying even at physiological GLP-1 concentrations, (c) tachyphylaxis observed with prolonged treatment, and (d) the limited effect on gastric emptying in individuals with slow gastric emptying before initiating treatment. Little information is available on the influence of diabetes mellitus itself (ie, in the absence of GLP-1 RA treatment) on retained gastric contents and pulmonary aspiration. Conclusion Prolonged fasting periods regarding solid meal components, point-of-care ultrasound examination for retained gastric content, and the use of prokinetic medications like erythromycin may prove helpful and represent an important area needing further study to increase patient safety for those treated with GLP-1 RAs.