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Glucagon-like peptide 1 receptor (GLP-1R) agonists exhibit anti-inflammatory actions, yet the importance of direct immune cell GLP-1R signaling remains uncertain. Although T cells respond to GLP-1, low receptor abundance and suboptimal antisera complicate efforts to characterize immune cell GLP-1R signaling. Here, we evaluate three frequently utilized GLP-1R antibodies, revealing that one of several antibodies, AGR-021, lack ideal specificity for detecting the GLP-1R in mice. Immunostaining with AGR-021 using tissues from two independent GLP-1R knockout mouse lines reveals persistent immunoreactive signals in GLP-1R-null pancreatic islets. Similarly, flow cytometry using AGR-021 reveals no reduction in AGR-021 immunoreactivity in GLP-1R-null splenic T cells. Moreover, western blotting detects AGR-021-immunoreactive proteins from a GLP-1R-negative cell line and fails to detect immunoreactive GLP-1R of the correct size upon overexpression of the receptor. Our findings reveal caveats governing use of multiple widely used GLP-1R antibodies, reemphasizing the importance of rigorous antibody validation for inferring accurate GLP-1R expression. Show less

The association between obesity and atrial fibrillation (AF) has garnered increasing attention. Obesity is a significant risk factor for cardiovascular diseases and promotes the occurrence of AF through multiple mechanisms. This study aims to explore the molecular mechanisms of obesity-induced AF using GLP-1R/GIPR dual-target agonist fusion protein (Fc) loaded into adipose-derived mesenchymal stem cell (ADSC) exosome-liposome hybrid nanoparticles (LE@Fc NPs). We successfully constructed and purified the Fc, verifying its purity and functional activity through SDS-PAGE and UV absorption spectroscopy. The fusion protein was then loaded into nanovesicles, and their morphology, size, and stability were assessed using transmission electron microscopy (TEM), nanoparticle tracking analysis (NTA), and dynamic light scattering (DLS). In vitro experiments demonstrated that LE@Fc NPs exhibit high fusion efficiency and targeted delivery capability. In vivo experimental results show that LE@Fc NPs significantly inhibit ferroptosis in the epicardial adipose tissue (EAT) of obese mice (iron content: 3.69 ± 0.36 vs. 0.88 ± 0.09), by restoring GSH levels (0.45 ± 0.08 vs. 0.87 ± 0.08) and Gpx4 expression (0.32 ± 0.06 vs. 1.01 ± 0.16), and reducing ROS (12.01 ± 0.95 vs. 2.68 ± 0.17), MDA (3.17 ± 0.29 vs. 0.95 ± 0.09), and 4-HNE (3.74 ± 0.51 vs. 0.91 ± 0.09) levels. Furthermore, LE@Fc NPs treatment significantly improved the inflammatory response (IL-1β: 44.08 ± 3.74 vs. 12.07 ± 0.65, IL-6: 515.59 ± 47.70 vs. 288.43 ± 16.81, MCP-1: 1401.04 ± 194.88 vs. 600.28 ± 45.54, TNF-α: 39.96 ± 2.48 vs. 18.01 ± 0.85). LE@Fc NPs also reduced atrial fibrosis, thereby effectively lowering the incidence of AF. Echocardiography and electrocardiogram monitoring revealed that LE@Fc NPs treatment significantly improved atrial remodeling and reduced the occurrence of AF in obese mice. In addition, LE@Fc NPs significantly improved obesity-induced systemic inflammation and metabolic disorders. In conclusion, LE@Fc NPs show great potential for the treatment of obesity-related AF. Show less

Aortic valve sclerosis affects 30 % of individuals over 65 and is associated with coronary artery disease, with risk of progression to aortic stenosis. Endothelial dysfunction, mediated by oxidative stress, impaired nitric oxide (NO) signaling, inflammation, and lipoprotein deposition, plays a central role in disease initiation and progression. This study investigated whether a combination of bioactive compounds could counteract these mechanisms and support vascular health. The effects of curcuma longa, coenzyme Q10, black garlic, vitamin B1, and vitamin D3 were tested in vitro on aortic valve endothelial cells. Cell viability, reactive oxygen species (ROS), and NO levels were quantified by commercially available kits, while gene expression was analyzed by RNA sequencing. A 4-week prospective pilot clinical study in 10 healthy volunteers without cardiovascular disease evaluated endothelial function and arterial stiffness. The compounds reduced ROS production (>27 %; p < 0.05), enhanced endothelial viability (>33 %; p < 0.05; except curcuma and black garlic), and increased NO production (>6 %; p < 0.05; except black garlic). Beneficial effects were reflected in upregulation of anti-atherosclerotic (GIPR, +0.058 copies per million, CPM; p < 0.05), antioxidant (GADL1, +0.55 CPM; p < 0.001), and anti-inflammatory (IL12A, +0.17 CPM; p < 0.01) genes. Clinically, daily supplementation improved endothelial function in participants found to have pre-existing endothelial dysfunction (p = 0.0336), with 50 % achieving normal levels after 4 weeks, while all subjects exhibited reduced arterial stiffness (p = 0.0016) without hepatic toxicity. The oral supplementation of the combination of these bioactive compounds improved endothelial function and vascular health, particularly in individuals with endothelial dysfunction, offering potential therapeutic benefits for cardiovascular health. Show less

Self-labelling proteins like SNAP- and HaloTag have advanced imaging in life sciences by enabling live-cell labeling with fluorophore-conjugated substrates. However, the typical one-fluorophore-per-protein system limits signal intensity. To address this, we developed a strategy using the ALFA-tag system, a 13-amino acid peptide recognized by a bio-orthogonal and fluorescently labelled nanobody, for signal amplification. We synthesized a pentavalent ALFA Show less

Osteoporosis diagnoses are increasing in the ageing population, and although some treatments exist, these have several disadvantages, highlighting the need to identify new drug targets. G protein-coupled receptors (GPCRs) are transmembrane proteins whose surface expression and extracellular activation make them desirable drug targets. Our previous studies have identified 144 GPCR genes to be expressed in primary human osteoclasts, which could provide novel drug targets. The development of high-throughput assays to assess osteoclast activity would improve the efficiency at which we could assess the effect of GPCR activation on human bone cells and could be utilised for future compound screening. Here, we assessed the utility of a high-content imaging (HCI) assay that measured cytoplasmic-to-nuclear translocation of the nuclear factor of activated T cells-1 (NFATc1), a transcription factor that is essential for osteoclast differentiation, and resorptive activity. We first demonstrated that the HCI assay detected changes in NFATc1 nuclear translocation in human primary osteoclasts using GIPR as a positive control, and then developed an automated analysis platform to assess NFATc1 in nuclei in an efficient and unbiased manner. We assessed six GPCRs simultaneously and identified four receptors (FFAR2, FFAR4, FPR1 and GPR35) that reduced osteoclast activity. Bone resorption assays and measurements of TRAP activity verified that activation of these GPCRs reduced osteoclast activity, and that receptor-specific antagonists prevented these effects. These studies demonstrate that HCI of NFATc1 can accurately assess osteoclast activity in human cells, reducing observer bias and increasing efficiency of target detection for future osteoclast-targeted osteoporosis therapies. Show less

Neurodegenerative diseases (NDDs) represent a heterogeneous group of disorders characterized by progressive neuronal loss, which results in significant deficits in memory, cognition, motor skills, and sensory functions. As the prevalence of NDDs rises, there is an urgent unmet need for effective therapies. Current drug development approaches primarily target single pathological features of the disease, which could explain the limited efficacy observed in late-stage clinical trials. Originally developed for the treatment of obesity and diabetes, incretin-based therapies, particularly long-acting GLP-1 receptor (GLP-1R) agonists and GLP-1R-gastric inhibitory polypeptide receptor (GIPR) dual agonists, are emerging as promising treatments for NDDs. Despite limited conclusive preclinical evidence, their pleiotropic ability to reduce neuroinflammation, enhance neuronal energy metabolism and promote synaptic plasticity positions them as potential disease-modifying NDD interventions. In anticipation of results from larger clinical trials, continued advances in next-generation incretin mimetics offer the potential for improved brain access and enhanced neuroprotection, paving the way for incretin-based therapies as a future cornerstone in the management of NDDs. Show less

Unimolecular peptides targeting the receptors for glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP) and glucagon (GCG) have been shown to improve glycaemic management in both mice and humans. Yet the identity of the downstream signalling events mediated by these peptides remain to be elucidated. Here, we aimed to assess the mechanisms by which a validated peptide triagonist for GLP-1/GIP/GCG receptors (IUB447) stimulates insulin secretion in murine pancreatic islets. Islets were isolated from wild-type (WT), Gipr-knockout (Gipr The triagonist promoted glucose-stimulated insulin secretion (GSIS) to a greater degree than co-administration of conventional mono-agonists in WT mouse islets. The triagonist-induced increase in GSIS was unchanged in the absence of either Gipr or Gcgr. However, the triagonist failed to enhance insulin secretion in islets lacking both Glp-1r and Gipr and upon treatment with the GLP-1 receptor-specific antagonist exendin-3 (9-39). Similarly, the specific blocking of Gαq signalling with YM254890 or transient receptor potential melastatin 5 (TRPM5) with triphenylphosphine oxide (TPPO) suppressed the triagonist-induced enhancement of GSIS. In vivo assessment of high-fat-fed Trpm5 Triagonist-induced augmentation of GSIS is primarily mediated through its interaction with the GLP-1 receptor and subsequent activation of the Gαq-TRPM5 signalling pathway. Given that Gαq is a key player in the amplification of GSIS, particularly under diabetic conditions, these findings highlight a GLP-1 receptor-centric pharmacological profile that underlies the potent effects of this multi-receptor agonist. Show less

Colorectal cancer (CRC) is a leading cause of cancer mortality while diabetes is a recognized risk factor for CRC. Here we report that tirzepatide (TZP), a novel polypeptide/glucagon-like peptide 1 receptor (GIPR/GLP-1R) agonist for the treatment of diabetes, has a role in attenuating CRC growth. TZP significantly inhibited colon cancer cell proliferation promoted apoptosis in vitro and induced durable tumor regression in vivo under hyperglycemic and nonhyperglycemic conditions across multiple murine cancer models. As glucose metabolism is known to critically regulate colon cancer progression, spatial metabolomics results revealed that glucose metabolites are robustly reduced in the colon cancer regions of the TZP-treated mice. TZP inhibited glucose uptake and destabilized hypoxia-inducible factor-1 alpha (HIF-1α) with reduced expression and activity of the rate-limiting enzymes 6-phosphofructo-2-kinase/fructose-2,6-bisphosphatase 3 (PFKFB3) and phosphofructokinase 1 (PFK-1). These effects contributed to the downregulation of glycolysis and the tricarboxylic acid (TCA) cycle. TZP also delayed tumor development in a patient-derived xenograft (PDX) mouse model accompanied by HIF-1α mediated PFKFB3-PFK-1 inhibition. Therefore, the study provides strong evidence that glycolysis-blocking TZP, besides its application in treating type 2 diabetes, has the potential for preclinical studies as a therapy for colorectal cancer used either as monotherapy or in combination with other anticancer therapies. Show less

The incretin hormone glucose-dependent insulinotropic polypeptide (GIP) stimulates bone remodeling postprandially. Species variations complicate the development of long-acting agonists with similar effects on rodent and human GIP receptors (GIPR). We created a series of long-acting molecules suitable for rat studies based on human GIP, stabilized with Aib insertion in position 2, lipidations in the middle region (compounds 1-4: positions 14/16/17/20) or the C-terminus (compound 5: position 40), and elongation with an exendin-4 tail in the C-terminus (Cex). The compounds were tested in vitro on the human and rat GIPR for cAMP accumulation, beta-arrestin recruitment and internalization. Pharmacokinetic profiling in rats was completed for two compounds, and one was selected for bone remodeling studies in rats (measurements of C-terminal telopeptide (CTX) and procollagen type 1 N-propeptide). All five compounds retained the potency and efficacy of native (human and rat) GIP in cAMP accumulation and arrestin recruitment on human and rat GIPR with no differences in relative activities from native GIP. Only compound 3 induced internalization like species-matched GIP on respective receptors and was chosen for in vivo assessments in rats. Mean T Show less

Pharmacological modulation of glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) through dual GIP/GLP-1 receptor agonists, commonly used for diabetes and obesity, shows promise in reducing alcohol consumption. We applied drug-target Mendelian randomization (MR) using genetic variation at these loci to assess their long-term effects on problematic alcohol use (PAU), binge drinking, alcohol misuse classifications, liver health, and other substance use behaviors. Genetic proxies for lowered BMI, modeling the appetite-suppressing and weight-reducing effects of variants in both the GIPR and GLP1R loci ("GIPR/GLP1R"), were linked with reduced binge drinking in the primary (β = -0.44, 95% CI [-0.72, -0.15], P = 2.42 × 10 Show less

Single molecules that combine complementary modes of action with glucagon-like peptide-1 receptor (GLP-1R) agonism are best-in-class therapeutics for obesity treatment. NN1706 (MAR423, RO6883746) is a fatty-acylated tri-agonist designed for balanced activity at GLP-1R and glucose-dependent insulinotropic peptide receptor (GIPR) with lower relative potency at the glucagon receptor (GcgR). Obese mice, rats and non-human primates dosed with NN1706 showed significant body weight reductions and improved glycemic control. In human participants with overweight or obesity, daily subcutaneous NN1706 treatment resulted in substantial body weight loss in a dose-dependent manner without impairing glycemic control (NCT03095807, NCT03661879). However, increased heart rate was observed across NN1706 treatment cohorts, which challenges further clinical development of NN1706. Show less

Statins are a commonly prescribed cholesterol lowering drug class that can increase the risk of new-onset diabetes (NOD). To investigate the molecular mechanisms underlying this effect, we generated human induced pluripotent stem cells (iPSCs) from individuals identified from electronic health records of Kaiser Permanente of Northern California who were susceptible to developing NOD after statin initiation or controls who maintained stable fasting glucose on statin treatment. RNA-seq analysis of iPSCs incubated with atorvastatin, simvastatin or mock buffer for 24 hours identified the long non-coding RNA Show less

Glucose-dependent insulinotropic polypeptide (GIP) was the first incretin identified and plays an essential role in the maintenance of glucose tolerance in healthy humans. Until recently GIP had not been developed as a therapeutic and thus has been overshadowed by the other incretin, glucagon-like peptide 1 (GLP-1), which is the basis for several successful drugs to treat diabetes and obesity. However, there has been a rekindling of interest in GIP biology in recent years, in great part due to pharmacology demonstrating that both GIPR agonism and antagonism may be beneficial in treating obesity and diabetes. This apparent paradox has reinvigorated the field, led to new lines of investigation, and deeper understanding of GIP. In this review, we provide a detailed overview on the multifaceted nature of GIP biology and discuss the therapeutic implications of GIPR signal modification on various diseases. Following its classification as an incretin hormone, GIP has emerged as a pleiotropic hormone with a variety of metabolic effects outside the endocrine pancreas. The numerous beneficial effects of GIPR signal modification render the peptide an interesting candidate for the development of pharmacotherapies to treat obesity, diabetes, drug-induced nausea and both bone and neurodegenerative disorders. Show less

Glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) are incretin hormones. Lack of GLP-1 receptor signaling has been reported to be compensated for by increased GIP secretion and action. Conversely, GLP-1 sensitivity has been reported to be increased in GIP receptor knockout ( Show less

Glucose-dependent insulinotropic polypeptide (GIP) is one of two incretin hormones playing key roles in the control of food intake, nutrient assimilation, insulin secretion and whole-body metabolism. Recent pharmacological advances and clinical trials show that unimolecular co-agonists that target the receptors for the incretins - GIP and glucagon-like peptide 1 (GLP-1) - offer more effective treatment strategies for obesity and type 2 diabetes mellitus (T2D) compared with GLP-1 receptor (GLP1R) agonists alone, suggesting previously underappreciated roles of GIP in regulating food intake and body weight. The mechanisms by which GIP regulates energy balance remain controversial as both agonism and antagonism of the GIP receptor (GIPR) produce weight loss and improve metabolic outcomes in preclinical models. Recent studies have shown that GIPR signalling in the central nervous system (CNS), especially in regions of the brain that regulate energy balance, is essential for its action on appetite regulation. This finding has sparked interest in understanding the mechanisms by which GIP engages brain circuits to reduce food intake and body weight. In this review, we present key knowledge around the actions of GIP on food intake regulation and the potential mechanisms by which GIPR and GIPR/GLP1R agonists may regulate energy balance. Show less

The use of incretin analogues has emerged in recent years as an effective approach to achieve both enhanced insulin secretion and weight loss in type 2 diabetes (T2D) patients. Agonists which bind and stimulate multiple receptors have shown particular promise. However, off target effects, including nausea and diarrhoea, remain a complication of using these agents, and modified versions with optimized pharmacological profiles and/or biased signaling at the cognate receptors are increasingly sought. Here, we describe the synthesis and properties of a molecule which binds to both glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) receptors (GLP-1R and GIPR) to enhance insulin secretion. HISHS-2001 shows increased affinity at the GLP-1R, as well as a tendency towards reduced internalization and recycling at this receptor Show less

Previous experiments have demonstrated that BGM0504, a GLP-1R/GIPR dual agonist drug by molecular dynamics-guided optimization, had enhanced agonistic activity compared to tirzepatide. This study aims to investigate its safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) in Chinese healthy volunteers. A randomized, double-blind, placebo-controlled and dose-escalation Phase I study was conducted as follows: a single dose (2.5 mg) and once-weekly administration for 2 weeks to reach target doses (5, 10 and 15 mg) by titration. A total of 40 volunteers received at least one dose of BGM0504 or placebo. The PK profile of BGM0504 was investigated over a wide dose range and supported once-weekly administration. It was observed that C BGM0504 was generally safe and well tolerated with favourable PK profile and potential role in weight loss was also confirmed. These findings support subsequent development of BGM0504 for type 2 diabetes mellitus (T2DM) and obesity. Show less

The glucagon-like peptide-1 receptor (GLP-1R) and glucose-dependent insulinotropic polypeptide receptor (GIPR) are important incretin receptors that are therapeutic targets for the treatment of type 2 diabetes and obesity. This study extensively characterised the metabolic phenotype of mice with global deletion of either the GLP-1R or GIPR side by side under identical conditions. Age-matched male wild-type (WT) C57Bl6NTac, GLP-1RKO or GIPRKO mice were placed on a high-fat or chow diet for 12 weeks, and a range of in vivo (weight gain, food intake, glucose tolerance, insulin tolerance, and whole-body energy metabolism) and ex vivo (white adipocyte lipolysis, brown adipose tissue and liver mitochondrial function, adipocyte and islet size, and hepatic steatosis) parameters were measured. While both WT and GLP-1RKO mice gained weight similarly on a HFD, obese high-fat-fed GLP-1RKO mice had altered glucose and insulin tolerance, and exhibited hepatic steatosis, highlighting the physiological importance of the GLP-1R in the regulation of blood glucose and lipid homoeostasis. In contrast, GIPRKO mice were partially resistant to diet-induced obesity compared to the WT mice, which was associated with a small reduction in food intake and intact epididymal and subcutaneous white adipocyte β-adrenoceptor-mediated lipolysis. Similarly, WT mice treated with a GIPR antagonist prevented weight gain due to a reduction in food intake on a HFD. These findings provide further support that the GLP-1R is important for normal glycaemic control, whereas the GIPR may play a role in the regulation of body weight. Show less

Incretin receptor agonists have been effective in combatting obesity and diabetes. While the body of knowledge regarding the signaling mechanisms of glucagon-like peptide 1 (GLP-1) receptor agonists is ever-growing, glucose-dependent insulinotropic polypeptide receptor (GIPR) agonists are less understood. The previewed papers offer insight into the impact of adipose GIPR on energy and weight homeostasis. Show less

G protein-coupled receptors (GPCRs) are transmembrane receptors that regulate intracellular signaling by interacting with G proteins and other effectors, influencing various physiological processes. The Glucose-dependent Insulinotropic Polypeptide Receptor (GIPR), a class B1 GPCR family member activated by GIP, regulates postprandial glycaemia by augmenting glucose-dependent insulin secretion, delaying gastric emptying, and suppressing appetite. Recent studies highlight the transmembrane domain (TMD) as the primary interface for dimerization, allowing GPCR to form homodimers or heterodimers with distinct physiological roles. However, the transient nature of these dimers challenges structural analysis, hindering experimental exploration and drug development. Computational methods now offer powerful tools for predicting such interactions. This study employs a hybrid approach, combining multiple protein docking software and dynamic structural optimization, to generate potential homodimeric models of GIPR-TMD. In addition, Next, validated models will provide insights into dimer activation mechanisms and support novel therapeutic discoveries. Show less

Multi-target peptide therapeutics targeting glucagon receptor (GCGR), glucagon-like peptide-1 receptor (GLP1R), and glucose-dependent insulinotropic polypeptide receptor (GIPR) represent a promising approach for treating diabetes and obesity. Triple agonist peptides demonstrate promising therapeutic potential compared to single-target approaches, yet rational design remains computationally challenging due to complex sequence-structure activity relationships. Existing methods, primarily based on convolutional neural networks, impose limitations including fixed sequence lengths and inadequate representation of molecular topology. Graph Attention Networks (GAT) offer advantages in capturing molecular structures and variable-length peptide sequences while providing interpretable insights into receptor-specific binding determinants. A dataset of 234 peptide sequences with experimentally determined binding affinities was compiled from multiple sources. Peptides were represented as molecular graphs with seven-dimensional node features encoding physicochemical properties and positional information. The GAT architecture employed a shared encoder with task-specific prediction heads, implementing transfer learning to address limited GIPR training data. Performance was evaluated using 5-fold cross-validation and independent validation on 24 literature-derived sequences. A genetic algorithm framework was developed for peptide sequence optimization, incorporating multi objective fitness evaluation based on predicted binding affinity, biological plausibility, and sequence novelty. Cross-validation demonstrated robust GAT performance across all receptors, with GCGR achieving high accuracy (AUC ROC: 0.915 ± 0.050), followed by GLP1R (AUC-ROC: 0.853 ± 0.059), and GIPR showing acceptable performance despite limited data (AUC-ROC: 0.907 ± 0.083). Comparative analysis revealed receptor-specific advantages: GAT significantly outperformed CNN for GCGR prediction (RMSE: 0.942 vs. 1.209, p = 0.0013), while CNN maintained superior GLP1R performance (RMSE: 0.552 vs. 0.723). Genetic algorithm optimization measurable improvement over baseline, with 4.0% fitness Enhancement and generation of 20 candidates exhibiting mean binding probabilities exceeding 0.5 across all targets. The GAT-based framework provides a computational approach in computational peptide design, demonstrating receptor-specific advantages and robust optimization capabilities. Genetic algorithm optimization enables systematic exploration of sequence space within existing agonist scaffolds while maintaining biological constraints. This approach provides a rational framework for prioritizing experimental validation efforts in triple agonist development. Show less

This study aimed to explore the molecular pathological mechanisms of the liver in metabolic disease-susceptible transgenic pigs via multiomics analysis. The triple-transgenic (PNPLA3 The TG2 pigs presented mild metaflammation and insulin resistance (IR) which was similar to WT12 pigs. Compared with the other three groups, the TG12 pigs presented severe hepatocyte ballooning, fat deposition, and portal area fibrosis. The transcriptome data suggested that the TG2 pigs presented upregulated gene expression in the extracellular matrix (ECM). The TG12 pigs presented more severe metaflammation and exhibited imbalanced glycolipid metabolism. Interestingly, genes such as ETNPPL, GABBR2, and BMP8B might be key regulatory targets for liver injury. The metabolome and lipidome suggested that long-chain polyunsaturated fatty acids (LCPUFAs) and phospholipids with corresponding LCPUFAs were remodelled. Importantly, bis(monoacylglycerol) phosphates (BMPs) and sulfatides (SLs) could be the key regulatory metabolites in liver injury. ETNPPL, GABBR2, and BMP8B might be potential therapeutic targets for liver injury. BMPs and SLs might be biomarkers for the diagnosis and treatment of liver diseases. Show less

Infiltration of adipocytes into the pancreatic parenchyma has been linked to impaired insulin secretion in individuals with increased genetic risk of T2D and prediabetic conditions. However, the study of this ectopic fat depot has been limited by the lack of suitable in vitro models. Here, we developed a novel 3D model of functionally mature human pancreatic adipose tissue organoids by aggregating human pancreatic adipose tissue-derived stromal vascular fraction (SVF) cells into organoids and differentiating them over 19 days. These organoids carry biological properties of the in situ pancreatic fat, presenting levels of adipogenic markers comparable to native pancreatic adipocytes and improved lipolytic and anti-lipolytic response compared to conventional 2D cultures. The organoids harbour a small population of immune cells, mimicking in vivo adipose environment. Furthermore, they express GIPR, allowing investigation of incretin effects in pancreatic fat. In accordance, GIP and the dual GLP1R/GIPR agonist tirzepatide stimulate lipolysis but had distinct effects on the expression of proinflammatory cytokines. This novel adipose organoid model is a valuable tool to study the metabolic impact of incretin signalling in pancreatic adipose tissue, revealing potential therapeutic targets of incretins beyond islets. The donor-specific metabolic memory of these organoids enables examination of the pancreatic fat-islet crosstalk in a donor-related metabolic context. Show less

In this study, to achieve more effective blood sugar lowering and weight-loss effects, eight glucagon-like peptide-1 (GLP-1)/glucose-dependent insulinotropic peptide (GIP)/glucagon (GCG) triple receptor agonists were designed and synthesized. Their sixteen related conjugates were obtained through Cys alkylation and Lys esterification modifications with two fatty acid side chains, respectively. After chemical structure confirmation using high-resolution mass spectrometry and peptide mapping, in vitro and in vivo biological effects of TRA01-24 were assessed. The structure-activity relationship (SAR) data on the amino acids, fatty acids, linkers and biological effects in vitro and in vivo of TRA01-24 have been summarized. Furthermore, peptide-protein molecular docking elucidated the structural basis for the biased agonist activity of TRA22 at GLP-1R, characterized by strong GLP-1R activation but weak GCGR and GIPR activation. In conclusion, a lead compound with excellent efficacy in vitro and in vivo, TRA24, was screened, which had better in vivo efficacy than tirzepatide in both normal and db/db mice. Show less

Glucagon-like peptide-1 receptor (GLP1R) agonists and glucose-dependent insulinotropic polypeptide receptor (GIPR) agonists may help treat metabolic dysfunction-associated steatotic liver disease (MASLD) and metabolic dysfunction-associated steatohepatitis (MASH). However, their definitive effects are still unclear. Our study aims to clarify this uncertainty. We utilised conventional Mendelian randomisation (MR) analysis to explore potential causal links between plasma GLP-1/GIP concentrations and MASLD and its related traits. Next, we conducted drug-target MR analysis using highly expressed tissue data to assess the effects of corresponding drug perturbation on these traits. Finally, mediation analysis was performed to ascertain whether the potential causal effect is direct or mediated by other MASLD-related traits. Circulating 2-h GLP-1 and GIP concentrations measured during an oral glucose tolerance test showed hepatoprotective effects on MASLD risk (OR GLP-1/GIP receptor agonists offer promise in lowering MASLD/MASH risk. GIP receptor agonists can exert direct and indirect effects on MASLD mediated by weight reduction or glycemic control improvement. Show less

Glucagon-like peptide-1 receptor (GLP-1R) and neuropeptide Y receptors (NPYRs) are expressed in reproductive tissues contributing to the regulation of gonadal function. This exploratory study examines the potential impact of their modulation by assessing the effects of exendin-4 (Ex-4) and peptide YY (PYY) (3-36) on endocrine ovaries and adrenals in high-fat diet (HFD) mice. Ex-4 and PYY(3-36) reduced blood glucose and energy intake, with no effects on body weight. While HFD did not impact the estrous cycle, Ex-4 increased metestrus frequency and decreased diestrus frequency resulting in 0% mice experiencing repeated diestrus or becoming acyclic. Luteinizing hormone levels were significantly higher in the Ex-4 and PYY(3-36) groups compared to the normal diet and HFD controls. In the adrenals, reduced capsule and zona glomerulosa thickness caused by HFD was reversed after peptide treatments. Within the ovaries, HFD increased the number of atretic follicles, an effect that disappeared after Ex-4 and PYY(3-36) treatments. Ex-4 also increased the number of corpora lutea owing to the prolonged metestrus phase. Gene expression analysis within the adrenals revealed the upregulation of Insr and the downregulation of Prgtr in HFD mice, while Ex-4 downregulated the expression of Gipr. The ovarian gene expression of Gipr, Npy1r and Prgtr was downregulated by Ex-4 treatment, while PYY(3-36) significantly downregulated the Prgtr expression compared to HFD mice. These data indicate that manipulating GLP-1R and NPY2R leads to changes in the reproductive physiology of mice. In addition, the observed alterations in the morphology and gene expression in the adrenals and ovaries imply a direct impact of these peptides on female reproductive function. Show less

The incretin receptor agonists semaglutide and tirzepatide have transformed the medical management of obesity. The neural mechanisms by which incretin analogs regulate appetite remain incompletely understood, and dissecting this process is critical for the development of next-generation antiobesity drugs that are more targeted and tolerable. Moreover, the physiologic functions of incretins in appetite regulation and gut-brain communication have remained elusive. Using in vivo fiber photometry, we discovered distinct pharmacologic and physiologic roles for the incretin hormones glucose-dependent insulinotropic peptide (GIP) and glucagon-like peptide-1 (GLP-1). We showed that GIP, but not GLP-1, was required for normal nutrient-mediated inhibition of hunger-promoting AgRP neurons. By contrast, both GIP and GLP-1 analogs at pharmacologic doses were sufficient to inhibit AgRP neurons. The magnitude of neural inhibition was proportional to the effect of each incretin on food intake, and dual GIP and GLP-1 receptor agonism more potently inhibited AgRP neurons and suppressed food intake than either agonist alone. Our results have revealed a role for endogenous GIP in gut-brain appetite regulation and indicate that incretin analogs act in part via AgRP neurons to mediate their anorectic effects. Show less

The gut hormone glucose-dependent insulinotropic polypeptide (GIP) signals via the GIP receptor (GIPR), resulting in postprandial potentiation of glucose-stimulated insulin secretion. The translation of results from rodent studies to human studies has been challenged by the unexpected effects of GIPR-targeting compounds. We, therefore, investigated the variation between species, focusing on GIPR desensitization and the role of the receptor C-terminus. The GIPR from humans, mice, rats, pigs, dogs and cats was studied in vitro for cognate ligand affinity, G protein activation (cAMP accumulation), recruitment of beta-arrestin and internalization. Variants of the mouse, rat and human GIPRs with swapped C-terminal tails were studied in parallel. The human GIPR is more prone to internalization than rodent GIPRs. Despite similar agonist affinities and potencies for G Desensitization of the human GIPR is dependent on the C-terminal tail. The species-dependent functionality of the C-terminal tail and the different species-dependent internalization patterns, especially between human and mouse GIPRs, are important factors influencing the preclinical evaluation of GIPR-targeting therapeutic compounds. This article is part of a themed issue Complexity of GPCR Modulation and Signaling (ERNST). To view the other articles in this section visit http://onlinelibrary.wiley.com/doi/10.1111/bph.v182.14/issuetoc. Show less