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Tirzepatide (TZP), a novel dual agonist of glucagon-like peptide (GLP)-1/glucose-dependent insulinotropic polypeptide (GIP) receptors (GLP-1R/GIPR), has been shown to reduce cardiovascular (CV) risk in patients with diabetes or obesity. This study investigated anti-atherosclerotic effects of TZP and the underlying mechanisms using apo E Show less

Alcohol use disorder (AUD) remains a major public health problem, with few effective medications currently available. However, peptides of the gut-brain axis appear to offer promising therapeutic targets for AUD as they influence the mesolimbic reward circuitry. Here, we examined the effects of tirzepatide, a long-acting dual glucagon-like peptide-1 receptor (GLP-1R) and glucose-dependent insulinotropic polypeptide receptor (GIPR) agonist approved for diabetes and obesity, using behavioural assays (locomotor activity and conditioned place preference), alcohol intake paradigms (intermittent access two-bottle choice, drinking in the dark and the alcohol deprivation effect), and molecular analyses (microdialysis, electrophysiology and proteomics) in rodents. First, tirzepatide effectively attenuated the rewarding properties of alcohol, measured through locomotor stimulation, conditioned place preference, and accumbal dopamine release (P < 0.001). Subsequently, this GLP-1R/GIPR agonist dose-dependently reduced voluntary alcohol consumption (P < 0.001), prevented binge (P < 0.01) and relapse-like drinking (P < 0.001), and maintained efficacy during repeated administration (P < 0.001). Finally, tirzepatide induced sustained synaptic depression in the lateral septum (P < 0.05) and further altered histone regulatory proteins in this region (P < 0.05), suggesting a potential neural substrate for its effects. Moreover, the GLP-1R/GIPR agonist affected metabolic parameters including body weight (P < 0.001), adipose tissue mass (P < 0.01), hepatic triglycerides (P < 0.01) and circulating pro-inflammatory cytokines (P < 0.05). Together, our findings suggest tirzepatide modulates alcohol-related behaviours through reward-related mechanisms while also affecting physiological consequences associated with long-term alcohol use. Given tirzepatide's established clinical use and the consistency of effects observed here, these results support further investigation for treating AUD and associated complications. The study is supported by grants from the Swedish Research Council (2023-2600, 2020-00559, 2020-01463, 2024-03054), LUA/ALF (723941 & 1005347) from the Sahlgrenska University Hospital, Alcohol Research Council of the Swedish Alcohol Retailing Monopoly (FO2024-0048), National Institutes of Health (NIH) (P50 AA010761 & U01 AA014095), U.S. Department of Veterans Affairs Office of Research and Development (BLR&D I01BX000813 & IK6BX006299), Herbert & Karin Jacobssons Foundation (2024-Forskning-225), Adlerbertska Research Foundation (2024-791), Wilhelm & Martina Lundgren's Research Foundation (2024-SA-4698), Åke Wibergs Foundation (M24-0216), Swedish Diabetes Foundation (DIA 2024-898) and Mary von Sydow Foundation (2024-36 & 2024-185). Thaynnam A Emous held an international internship scholarship from the São Paulo Research Foundation (FAPESP), Process Number #2023/18470-5, while conducting research at the University of Gothenburg. Show less

This first-in-human Phase I study evaluated the safety, tolerability, pharmacokinetics (PK) and pharmacodynamics (PD) of KN069, a novel dual Glucagon-like peptide-1 receptor agonist (GLP-1RA)/Glucose-dependent insulinotropic polypeptide receptor (GIPR) antagonist in Chinese men with overweight/obesity. This randomised, double-blind trial included a single ascending dose (SAD; 12-120 mg, N = 36, 3:1 active-to-placebo) and a multiple ascending dose (MAD; N = 12, dose escalation 15-60 mg) phase. Safety was assessed via adverse events (AEs) and compliance. PK was analysed using a sandwich enzyme-linked immunosorbent assay (ELISA) for Intact and Total KN069. PD included measurements of body weight, waist circumference, body mass index (BMI) and metabolic parameters. Immunogenicity was assessed by detecting anti-drug antibodies (ADA). KN069 was well tolerated, with predominantly mild-to-moderate gastrointestinal adverse events. PK showed dose-proportional exposure (12-90 mg) with a long half-life for Total KN069 (899.74-1099.01 h). In the SAD part, preliminary dose-dependent weight reductions were observed, with maximum early changes at Day 7 (90 mg: -4.71% vs. placebo: -0.41%) and sustained for up to 133 days. In the MAD part, Group B (60 mg) achieved a -2.57% mean weight reduction from baseline at Day 25, alongside a significant decrease in waist circumference (p = 0.0446). Metabolic improvements included lower fasting glucose, triglycerides, uric acid and elevated insulin/C-peptide. KN069 exhibits favourable safety, long-acting PK and preliminary dose-dependent weight reduction alongside expected pharmacologic metabolic effects, supporting further clinical development. gov Identifier: NCT06547775. Show less

Critical limb ischemia (CLI) represents a severe vascular complication of type 2 diabetes, primarily driven by impaired angiogenic capacity, and frequently results in limb amputation or mortality. Here, we investigated the therapeutic potential of tirzepatide in promoting perfusion recovery in diabetic hindlimb ischemia and delineated the underlying molecular mechanisms. Human umbilical vein endothelial cells (HUVECs) exposed to high glucose were employed to evaluate tirzepatide's effects on endothelial proliferation, migration, and tube formation, alongside the activation of Akt, endothelial nitric oxide synthase (eNOS), and extracellular signal-regulated kinase 1/2 (ERK1/2) signaling, assessed by western blotting. Knockdown of GLP-1R or GIPR abrogated the pro-angiogenic effects of tirzepatide, while pharmacological inhibition of the Akt/eNOS or ERK1/2 pathways attenuated endothelial responses. In vivo, tirzepatide treatment significantly enhanced perfusion recovery and increased capillary density in the ischemic limbs of diabetic mice, corroborating its angiogenic effects. Collectively, these findings demonstrate that tirzepatide facilitates angiogenesis and accelerates ischemic limb revascularization through dual GLP-1R/GIPR activation and subsequent engagement of Akt/eNOS and ERK1/2 signaling pathways, highlighting its potential as a therapeutic strategy for diabetic CLI. Show less

Functional co- and tri-agonists at the receptors for GLP-1, GIP and glucagon effectively decrease body weight and hyperglycemia but are associated with adverse gastrointestinal effects related to GLP-1R agonism. Here we report the discovery that obesity can be reversed in the absence of a functional GLP-1R. It propelled the identification of a unimolecular GIPR:GCGR co-agonist lacking GLP-1 activity that corrects obesity in obese mice and rats. Selective, dual, and triple sustained-action agonists at GIPR, GCGR and GLP-1R were used to assess body weight and glucose management in diet-induced obese (DIO) wildtype (WT) and GLP-1R knock-out (KO) mice. Indirect calorimetry and pair-feeding studies were used to characterize the magnitude of weight lowering specifically to suppression of food intake relative to energy expenditure. When used in physical co-mixture, selective GIPR agonism interacts with selective GCGR agonism to correct obesity and enhance glycemia in DIO mice. Retatrutide a balanced GLP-1R:GIPR:GCGR triagonist normalized body weight in obese GLP-1R KO mice. BWB3054, a fatty acylated GIPR:GCGR co-agonist, was identified as comparably potent as retatrutide to induce cAMP production at the mGIPR, and 4-fold reduced at mGCGR, but notably more than 100-fold diminished at mGLP-1R. Despite minimal relative GLP-1R potency, BWB3054 reduces excess body weight in obese DIO-mice to a similar degree as that observed for retatrutide in obese GLP-1R KO mice. Correction of obesity and glycemia in mice without employing GLP-1 agonism was demonstrated by three independent methods (GLP-1R KO with retatrutide, GIPR:GCGR physical co-agonism mixture, and GIPR:GCGR covalent co-agonist) which advocate for the prospect that the adverse GI effects commonly associated with its use might be avoided. Show less

Future directions in incretin research: Three major directions currently shape therapeutic innovation in incretin research: multi-receptor agonism, oral drug development, and mechanistic reappraisal of glucose-dependent insulinotropic polypeptide (GIP) physiology. These advances indicate that incretin-based therapies should be understood within an integrated enteroinsular network rather than through isolated hormone actions. DPP-4, dipeptidyl peptidase-4; GCGR, glucagon receptor; GIPR, GIP receptor; GLP-1, glucagon-like peptide-1; GLP-1R, GLP-1 receptor; T2D, type 2 diabetes. Show less

Incretin-based pharmacology has revolutionized the medical treatment of type 2 diabetes and obesity. The most effective drug to date is tirzepatide, a dual incretin receptor agonist that engages both the glucagon-like peptide-1 receptor (GLP-1R) and the glucose-dependent insulinotropic polypeptide receptor (GIPR). While the relative contributions of GIPR and GLP-1R actions to the clinical effects of tirzepatide have not been established, the potency of this agent has reignited interest in the clinical potential of GIPR agonism. Here, we discuss incretin biology as it relates to metabolic pharmacology and contextualize the mechanisms by which GIPR activity could contribute to the development of new and effective drugs. We explore current and future applications of GIPR agonists and antagonists, to underscore the potential that this signaling system could add to treatment of type 2 diabetes and obesity. Show less

The development of glucagon-like peptide 1 (GLP1) receptor agonists, including semaglutide and tirzepatide, has transformed the clinical management of overweight and obesity. However, substantial inter-person variability exists in both weight loss efficacy and the incidence of side effects Show less

Multispecific therapeutics represent an increasingly important approach for enhancing the efficacy in complex diseases. Here, we report the design and optimization of novel antibody-peptide conjugates that combine glucose-dependent insulinotropic polypeptide receptor (GIPR) antagonism with glucagon-like peptide 1 (GLP-1) receptor (GLP-1R) agonism for the treatment of obesity. A series of hybrid molecules was generated by conjugating synthetic GLP-1 peptides to IgG-based anti-GIPR antibodies, yielding markedly prolonged systemic exposure of the structurally intact GLP-1 peptide. In diet-induced obese mice and obese monkeys, once weekly administration of anti-GIPR-Ab/GLP-1 conjugates produced sustained body weight loss and improvements in metabolic parameters. This optimization effort culminated in the discovery of AMG 133, currently in phase III clinical trials with a profile that may support monthly dosing. Show less

Obesity and type 2 diabetes have reached pandemic proportions, largely driven by sedentary lifestyles and unhealthy dietary habits. According to the World Obesity Atlas 2024, by 2035 more than 4 billion adults and children are expected to be living with overweight or obesity, up from 2.2 billion in 2020. These alarming trends contribute substantially to morbidity and mortality from noncommunicable diseases, underscoring the urgent need for innovative and effective therapeutic strategies. The present study aimed to design and develop a novel GLP-1/GIP/GCG receptors triagonist with high and balanced efficacy across all three biological targets. Advanced computer-aided drug design approaches were employed to optimize pharmacological activity and identify promising multi-receptor agonists rationally. Integrated bioinformatics analyses enabled identification of key sequence determinants and optimal modification sites, while molecular dynamics simulations elucidated the impact of stapling and staple positioning on α-helical stability and conformational rigidity in incretin-like peptides. Guided by these insights, 22 novel triagonistic structures were designed, synthesized, and evaluated Show less

Glucose-dependent insulinotropic polypeptide (GIP) is a gut-derived incretin hormone, and pharmacologic modulation of central GIP receptors (GIPRs) improves energy homeostasis and prevents conditioned taste avoidance (CTA). However, the mechanisms by which GIPR signaling impact food intake and aversion are incompletely understood. Here, we show that GIPR agonism abrogates the aversive and enhances the anorexigenic effects of the pro-inflammatory cytokine interleukin-1β (IL-1β). Aversion-encoding parabrachial calcitonin gene-related peptide (CGRP) neurons were required for IL-1β-induced CTA but not anorexia. Moreover, systemic IL-1β increased CGRP neural activity in vivo, and this was significantly attenuated by co-administration of a GIPR agonist. By contrast, GIPR in the dorsal vagal complex was required for the acute anorectic effect of GIPR agonism but not its anti-aversive effect. Taken together, our data suggest that GIPR agonism reduces food intake and prevents aversion via distinct circuits and that GIPR agonism may represent an effective approach to alleviate inflammation-induced aversion. Show less

Glucagon-like peptide-1 (GLP-1) is an incretin hormone secreted by intestinal endocrine L cells that activates the GLP-1 receptor (GLP-1R), leading to glucose-dependent insulin secretion and suppression of glucagon release. In recent years, GLP-1R agonists (GLP-1RAs) have become one of the leading therapeutic options for the treatment of type 2 diabetes mellitus; however, for a long time clinically approved GLP-1RAs were limited to peptide drugs unsuitable for oral administration. The discovery of the "first-in-class" small molecule agonist danuglipron in 2018 demonstrated the feasibility of orally available GLP-1RAs and stimulated the development of numerous danuglipron-like compounds, some of which showed increased efficacy over the prototype. In this study, we report the design and synthesis of novel GLP-1RAs based on a regioisomeric danuglipron scaffold, 1 Show less

The underlying mechanism of recurrent pregnancy loss (RPL) is still not fully understood. We aimed to identify the key genes involved in the process by which obesity influences RPL. RPL and obesity data were retrieved from the GEO database. The differentially expressed genes (DEGs) between disease and normal samples among RPL and obesity were selected. Through intersecting the above DEGs, important DEGs were obtained. GO and KEGG analyses were used to analyze the function of these important genes. Two algorithms (LASSO and SVM) and receiver operator characteristic (ROC) analysis were used to optimize the DEGs. Furthermore, the immune infiltration and single gene enrichment analysis were performed to explore the correlations between key biomarkers and immune cells. A total of 1857 RPL-related DEGs and 2880 obesity-related DEGs were selected, respectively. Through intersecting the above two parts of DEGs, 100 important genes were obtained, which were involved in immune response processes such as the EGFR tyrosine kinase inhibitor resistance JAK-STAT signaling pathway, and T cell receptor signaling pathway. Through LASSO, SVM, and ROC analyses, five down-regulated optimal genes in RPL were finally considered as biomarkers in obesity-related RPL: GIPR, KRTAP4-11, NFU1, OPN4, and PRMT7. The five biomarkers showed effective diagnostic ability in RPL, with AUC above 0.8. Furthermore, eosinophils, CD56 bright natural killer cells, and monocytes were significantly correlated with the five biomarkers. This study identified five effectively diagnostic genes and explored their correlations with immune cells, providing indications for the following development of diagnostic tools and potential mechanism exploration. Show less

Our understanding of the intrinsic mechanisms that drive the regeneration of damaged axons after a spinal cord injury is still limited. Microtubules are core components of the eukaryotic cytoskeleton and are essential for axonal growth, in part because their stability is governed by post-translational modifications in mature neurons. Glucose-dependent insulinotropic polypeptide (GIP) and its receptor (GIPR) are expressed in multiple extra-pancreatic tissues, suggesting biological functions beyond classical endocrine signaling; however, their roles in neuronal cytoskeletal regulation are not well defined. Here, we investigated the effects of GIP in cultured cortical neurons. GIP enhanced microtubule stability and increased the number of axons crossing an inhibitory chondroitin sulfate proteoglycan (CSPG) border. Mechanistically, GIP promoted microtubule acetylation via α-tubulin N-acetyltransferase 1 (αTAT1), the major acetyltransferase for α-tubulin, by suppressing αTAT1 ubiquitination and thereby reducing its proteasomal degradation in inhibitory environments. Although the upstream mechanism remains to be determined, this study provides the first evidence that GIP/GIPR signaling modulates microtubule dynamics, highlighting a potential strategy to re-activate neuronal growth machinery after injury. Show less

The incretin hormone glucagon-like peptide-1 (GLP-1) exerts potent effects on glucose metabolism, prompting the development of therapeutic strategies that enhance activity of the GLP-1 receptor (GLP-1R) pathway. Inhibitors of dipeptidyl peptidase 4 (DPP-4) prolong the half-life of endogenous GLP-1 and typically achieve reductions in HbA1c of 0.5%-0.8%. However, large-scale cardiovascular (CV) outcomes trials (CVOTs) with DPP-4 inhibitors demonstrated CV safety but did not show a reduction in CV events. A second incretin-based therapeutic approach was the development of GLP-1R agonists (GLP-1RAs). Various GLP-1RAs, including liraglutide, semaglutide, and dulaglutide, demonstrated a reduction in CV outcomes in large CVOTs. Initially, these medications were only available as injectable agents for subcutaneous administration, but recent technological advancements have enabled the development of orally available GLP-1RAs. A third incretin-based approach is tirzepatide, a dual agonist of GLP-1R and glucose-dependent insulinotropic polypeptide receptor (GIPR), which achieves greater HbA1c reduction and weight loss compared with GLP-1RAs alone. Ongoing large-scale CVOTs will determine its effects on hard cardiovascular endpoints. This Review summarizes the effects of GLP-1 and GLP-1RAs in the CV system as well as clinical data of GLP-1RAs in individuals with CV disease or high CV risk. Show less

Dual GIP/GLP-1 receptor agonists have gained significant attention in clinical applications because of their remarkable efficacy in reducing obesity and type 2 diabetes. However, the mechanisms by which these dual agonists affect systemic metabolism remain elusive. To investigate the effects of a novel dual-receptor agonist, THDBH120, on systemic metabolism in obese individuals and the specific roles of GIPR and GLP-1R in modulating systemic and adipose tissue metabolism. To evaluate the intrinsic properties of THDBH120, we conducted a potency assay by using HEK293 cell lines overexpressing either human GIPR or GLP-1R and measured the accumulation of cAMP as a downstream second messenger following receptor activation. To evaluate the efficacy of THDBH120 on systemic metabolism, we used obese rodents and nonhuman primate species that received various doses and frequencies of THDBH120. To determine the metabolic roles of GLP-1R and GIPR in mediating the beneficial effects of THDBH120, we used GLP-1R- and GIPR-knockout mouse models treated with THDBH120, the GLP-1R agonist semaglutide, or the GIPR agonist LAGIPRA and performed transcriptomic sequencing analyses of adipose tissues. THDBH120 is a novel long-acting dual GIPR/GLP-1R agonist that has superior weight loss and metabolic improvement effects in rodents and mammals. The activation of GLP-1R by semaglutide or THDBH120 improved lipid metabolism, whereas the activation of GIPR by LAGIPRA or THDBH120 alleviated inflammation. THDBH120 improved lipid metabolism via GLP-1R-mediated pathways and mitigated inflammation by activating GIPR-associated pathways in the adipose tissues of obese mice. Both GLP-1R and GIPR are important in mediating the beneficial effects of dual receptors on systemic metabolism. THDBH120 is a novel long-acting dual GIPR/GLP-1R agonist that has potential clinical applications. Show less

The induction of nausea and emesis represents a significant barriers to optimizing weight loss medications for the treatment of obesity. Identifying mechanisms that improve tolerability and/or enhance efficacy without induction of emetic neurocircuitry could provide substantial therapeutic benefits. Candidate peptide YY (PYY)-based approaches for obesity treatment are no exception, as PYY-based therapeutics are uniformly associated with nausea and emesis. Recently, interest in glucose-dependent insulinotropic polypeptide receptor (GIPR)-based therapeutics has resurfaced, with some paradoxical findings from several preclinical studies showing that both GIPR agonism and antagonism, when combined with glucagon-like peptide-1 receptor (GLP-1R) agonists, result in greater body weight loss and superior glycemic control compared to GLP-1R agonism alone. Here, we investigated the effects of pharmacological modulation of the GIPR system on the actions of PYY. We found that systemic GIPR agonism attenuated PYY-induced malaise while preserving its anorectic and body weight-lowering effects in rats. Interestingly, GIPR antagonism enhanced PYY-induced hypophagia and body weight loss without compromising its malaise tolerability profile. Furthermore, inhibition of GIPR signaling significantly reduced PYY-induced c-Fos expression in the area postrema (AP) of the hindbrain. Since both NPY2R and GIPR are expressed in the same AP neurons, this suggests a potential neuronal pathway by which GIPR modulates the effects of PYY. Overall, our findings underscore the multifaceted actions of the GIPR system and highlight the therapeutic potential of both GIPR agonism and antagonism in enhancing and improving the effects of PYY-based obesity treatments. Show less

Periodontal ligament stem cells (PDLSCs) hold great promise for periodontal regeneration therapy. However, their self-renewal and multilineage differentiation capabilities are often compromised by adverse factors in the periodontal microenvironment. Therefore, identifying novel therapeutic targets and elucidating the underlying molecular mechanisms to protect the proliferative and differentiation potential of PDLSCs is of significant importance. PDLSCs were exposed to electronic cigarette extract and various common oral stressors to evaluate the expression of glucagon such as peptide 1 receptor (GLP1R) and gastric inhibitory polypeptide receptor (GIPR). PDLSCs isolated from patients with periodontitis and PDLSCs from a mouse periodontitis model were also analyzed. Functional studies were performed by GLP1R or GIPR knockdown, overexpression, and treatment with single or dual receptor agonists, followed by assessment of cell proliferation and multilineage differentiation capacities. Transcriptome (RNA-seq), chromatin immunoprecipitation sequencing (ChIP-seq), and RNA immunoprecipitation sequencing (RIP-seq) were applied to delineate downstream signaling pathways and RNA–protein interactions. Protein synthesis regulation was further investigated by immunoprecipitation of interferon induced protein with tetratricopeptide repeats (IFIT)-associated translation initiation factors. For in vivo validation, wild-type and GLP1R/GIPR double-knockout periodontitis mice were transplanted with CRISPR-Cas9 mCherry-labeled PDLSCs and treated with receptor agonists. Disease severity and PDLSC fate were evaluated by histology and lineage tracing. Finally, a questionnaire-based survey was conducted in 150 patients with periodontitis, including 74 individuals with long-term use (> 1 month) of GLP1R or GLP1R/GIPR dual agonists (e.g., semaglutide, liraglutide, tirzepatide), to assess their periodontal outcomes. GLP1R and GIPR expression were markedly downregulated in PDLSCs exposed to multiple stressors and in PDLSCs isolated from periodontitis specimens. RNA-seq, ChIP-seq, and RIP-seq identified downstream pathways and RNA–protein interactions implicated in receptor-mediated regulation. Functionally, GIPR agonism promoted PDLSC proliferation via activation of the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated kinase (ERK) pathway, whereas GLP1R agonist enhanced multilineage differentiation capacity in vitro. Mechanistically, GLP1R knockdown induced robust upregulation of IFIT1/2/3, while GLP1R agonist suppressed IFIT expression. IFIT1/2/3 were shown to interact with eIF3C and to inhibit translation of differentiation-related mRNAs, linking GLP1R signaling to translational control of PDLSC fate. In vivo, transplantation experiments in both wild-type and GLP1R/GIPR double-knockout periodontitis mice demonstrated that single and dual receptor agonists significantly improved endogenous and exogenous PDLSC-mediated periodontal regeneration. Consistently, a clinical survey of 150 patients with periodontitis (74 receiving GLP1R or dual agonists) revealed significantly better periodontal staging and grading in treated individuals, with longer agonist exposure associated with greater improvement. Our findings uncover the different molecular roles of GIPR and GLP1R in self-renewal capacity and multipotency of PDLSCs, and open new avenues for developing therapeutic targets and strategies in oral tissue engineering and regenerative medicine. The online version contains supplementary material available at 10.1186/s11658-026-00867-2. Show less

Unimolecular triagonists drive substantial weight loss in patients with obesity by engaging the glucagon-like peptide 1 receptor (GLP-1R) and glucose dependent insulinotropic polypeptide receptor (GIPR) to reduce food intake (FI) and the hepatic glucagon receptor (GcgR) to enhance energy expenditure (EE). However, their development has been challenged by deleterious cardiovascular (CV) effects, including increased heart rate (HR), elongated QTc, and arrhythmia mediated by GcgR agonism. GLP-1R mono-agonists on the other hand improve both obesity and CV outcomes with negligible effects on EE. We sought to imbue peptide GLP-1R agonists with an EE enhancing effect by combining them with ectopic GLP-1R expression and agonism in hepatocytes. We used an adeno-associated virus (AAV) to induce the expression of a functional, liver-specific GLP-1R combined with traditional peptide agonist treatment to drive greater body weight loss via reduced energy intake and increased energy expenditure. Agonism of the ectopic GLP-1R with either semaglutide, a cAMP biased GLP-1R analogue (NNC5840), or a dual GLP-1R/GIPR agonist in wild-type (WT) diet induced obese (DIO) mice led to enhanced EE and improved weight loss compared to peptide agonist treatment alone. This represents a novel mechanism for achieving poly-pharmacology to treat obesity. Show less

Type II diabetes mellites (TIIDM) characterized by hyperglycemia, insulin resistance, insensitivity, and pancreatic β-cell atrophy has gained concern due to high rise in such cases globally. This study highlighted the therapeutic potency of a novel polyherbal formulation (PHF) of Phyllanthus urinaria and Adhatoda vasica Nees mice by in vitro, in vivo, and in silico analysis in high-fat diet (HFD)-streptozotocin (STZ)-induced Swiss albino. The findings showed significant inhibition of α-amylase and α-glucosidase activity of the PHF along with decreased blood glucose level, increased glycogen and serum insulin level, elevated mRNA expression of GIPR and GLP1R, GLUT2, GLUT4, INSR, INS1, INS2, TCF7L2, and Pdx1 in both low and high dose of PHF-treated mice as compared to HFD-STZ-induced diabetic mice. Western blot results also demonstrated augmented insulin protein level in both PHF-treated groups. Okanin and vomicine, identified from LCMS analysis as potent antidiabetic bioactive compounds bind to dipeptidyl peptidase 4 (DPP4) with a binding energy of -8.04 and -7.81 kcal/mol, respectively, as compared to standard drug metformin (-5.33 kcal/mol). Inhibition of DDP-4 by bioactives of PHF aids in enhanced secretion of incretion hormones leading to insulin secretion thereby established itself as a complementary and alternative therapeutics in the management of diet-induced TIIDM. Show less

Harnessing the simultaneous activation of GLP-1R, GIPR, and GCGR has emerged as a highly promising therapeutic paradigm for obesity and related metabolic diseases, including nonalcoholic steatohepatitis (NASH). Here, we report the discovery of TPM003, a novel unimolecular GLP-1R/GIPR/GCGR triple agonist engineered by using a long-acting PEG-fatty acid (PEG-FA) stapling technology. TPM003 exhibits balanced triple receptor agonism and demonstrates an extended systemic half-life across multiple species. In obese mice, TPM003 induced robust and durable weight loss, accompanied by broad improvements in metabolic parameters, outperforming current GLP-1RA standards. Importantly, TPM003 also effectively reversed hepatic steatosis and improved markers of liver function in multiple NASH models. Furthermore, TPM003 is compatible with SNAC-based absorption enhancement, enabling oral delivery in a tablet formulation. Collectively, these findings highlight the therapeutic advantages of balanced GLP-1R/GIPR/GCGR agonism for obesity and NASH and support TPM003 as a promising preclinical candidate with translational potential. Show less

Dipeptidyl peptidase-4 (DPP-4) inhibitors enhance circulating levels of biologically intact incretins, yet the relative contribution of glucose-dependent insulinotropic polypeptide (GIP) to their metabolic effects remains incompletely understood. While glucagon-like peptide-1 (GLP-1) has long been emphasized in incretin biology, emerging evidence suggests important physiological roles for GIP. This study investigated whether endogenous GIP signaling is indispensable for the glucose-lowering and anti-obesity effects of DPP-4 inhibition. Male Gipr DPP-4 inhibition significantly improved glucose tolerance and attenuated body-weight gain in HFD-fed Gipr Endogenous GIP signaling is essential for both glucose-lowering and anti-obesity actions of DPP-4 inhibitors in mice. GLP-1 elevation alone is insufficient to compensate for GIP receptor deficiency. These findings refined the mechanistic understanding of DPP-4 inhibitors, highlighted the physiological importance of GIP, and suggested context-dependent metabolic actions of incretins. Show less

Tirzepatide is an anti-obesity drug based on dual agonism of the incretin receptors GLP-1R and GIPR. Its anti-obesity effect is largely based on its action of reducing food intake. However, there are indications that tirzepatide exerts effects on adipose tissues beyond those resulting from fat loss due to reduced food intake. To investigate this, we treated mice, previously been made obese through high-fat diet, with tirzepatide. We also established an experimental group of mice pair-fed with those treated with tirzepatide, key to distinguish the specific effect of tirzepatide from food intake reduction-mediated effects. Both groups experienced similar reduction in body weight, with a trend toward greater loss in visceral and subcutaneous white fat in mice under tirzepatide treatment. Glucose tolerance improved in tirzepatide-treated obese mice, independently of reduced food intake. Tirzepatide treatment also lowered the inflammatory status of obese mice, which in this case, was attributable to decreased food consumption. Tirzepatide exerted distinct effects on brown adipose tissue relative to white adipose tissues, significantly boosting thermogenic activity and modifying its gene expression pattern, including the upregulation of genes linked to thermogenesis and substrate oxidation. White adipose tissues responded differently, being primarily affected in their lipid metabolism. These effects were specific to tirzepatide treatment and not attributable to reduced food intake. Our results indicate that tirzepatide affects the function and metabolism of adipose tissues and especially induces activation of brown adipose tissue in mice, which may be relevant for future human studies to ascertain the mechanisms of tirzepatide metabolic benefits. Show less

Internalisation of G protein-coupled receptors (GPCRs) can contribute to altered cellular responses by directing signalling from non-canonical locations, such as endosomes. If signalling processes are locally constrained, active receptors in different subcellular locations could produce different downstream effects. This phenomenon may be relevant to the optimal targeting of the glucagon-like peptide-1 receptor (GLP-1R), a type 2 diabetes and obesity target GPCR for which several ligands with varying internalisation tendency have been discovered. To investigate, we compared the signalling localisation effects of two prototypical GLP-1RAs with opposite signal bias and effects on GLP-1R trafficking: exendin-asp3 (ExD3), a full agonist that drives rapid internalisation, and exendin-phe1 (ExF1), which shows much slower internalisation. After using bioorthogonal labelling and fluorescent agonist conjugates to verify the divergent trafficking patterns of ExF1 and ExD3 in β-cell lines and primary pancreatic islets, we used live cell biosensors to monitor signalling at different subcellular locations. This revealed that cAMP/PKA/ERK signalling in β-cells is in fact distributed widely across the cell over short- (<5 min) and medium-term (up to 60 min) stimulation at pharmacological (>10 pM) concentrations, with no major differences in signal localisation that could be linked to internalised versus cell surface-bound GLP-1R. Moreover, washout experiments highlighted that, whilst fast-internalising ExD3 shows much greater accumulation and binding to GLP-1R in endosomes than slow-internalising ExF1, it is a rather inefficient driver of both cAMP production in β-cells and insulin secretion from perfused rat pancreata. These data provide a greater understanding of the cellular effects of biased GLP-1R agonism. Show less

Glucagon-like peptide-1 receptor agonists (GLP-1RAs) are increasingly used for T2DM and obesity. An electronic search was conducted in Scopus, PubMed/MEDLINE, and Google Scholar databases. Retatrutide (LY3437943) is a novel triple agonist targeting glucagon receptor (GCGR), glucose-dependent insulinotropic polypeptide receptor (GIPR), and glucagon-like peptide-1 receptor (GLP-1 R). In subjects with type 2 diabetes mellitus (T2DM), decreased glycated hemoglobin (HbA These promising effects on glycemic control, weight loss, and emerging pleiotropic actions merit further investigation. Show less

Class B1 GPCRs are crucial to maintaining homeostasis along a multitude of vital biochemical pathways. Understanding the activation mechanism of these proteins at both a family and clade-specific level is particularly relevant for designing multi-target agonists, as exemplified by recently designed dual-agonists for GLP-1R and GIPR, for treating obesity. Here, we use 6 milliseconds of unbiased all-atom MD simulations of GCGR, GLP1R, PAC1R, SCTR, PTH1R and CALCR from the four different clades of Class B1 GPCRs to establish the universal mechanism of their activation. We show that the activation of Class B1 GPCRs involves a clade-independent intermediate state characterized by the outward movement of helix 6. We use a combination of Markov state models and transition path theory to show that the activation of these proteins occurs at a millisecond timescale. We identify characteristic molecular locks that are conserved at a clade-level, showcasing the uniqueness among the activation mechanisms of these proteins. We show that these proteins show similar inactive and active states, but show unique activation mechanisms at a residue level. These sites can be targeted directly or allosterically to design therapeutics targeting a specific clade of proteins. Thus, this study provides an integrated atomistic view of the activation for Class B1 GPCRs from a mechanistic, thermodynamic and kinetic perspective. Show less

The epidemics of metabolic disease, in the form of obesity and type 2 diabetes, are a growing public health concern. However, incretin-based therapeutics have transformed our ability to address these diseases. While this current generation of incretin analogues show weight regain upon cessation of treatment, the amount of which can depend on the treatment and patient, iterative advancements may improve weight loss durability in the long term. In this review, we discuss the development of glucagon like peptide-1 receptor (GLP-1R) agonists and GLP-1R/ glucose-dependent insulinotropic polypeptide receptor (GIPR) co-agonists, and how future generations will leverage this strategy. We focus our review on glucagon receptor (GCGR) agonism, which has recently been combined with both GLP-1R and GLP-1R/GIPR agonism to generate dual (e.g. survodutide, cotatutide, mazdutide, etc) and triple agonists (e.g. retatrutide, etc) for improved body weight loss via energy expenditure stimulation. We rely on largely pre-clinical evidence for action because clinical data is extremely limited for GCGR agonism. Herein, we review mechanisms by which glucagon receptor agonists act to increase energy expenditure. Finally, we discuss future improvements to incretin-based therapeutics, and how they can include strategies that target the GCGR. The purpose of this review is to discuss mechanisms by which GCGR agonism can reduce body weight and put them in the context of the combination with incretin receptor agonists. Mechanistic data has only currently been evaluated in preclinical rodent models and evidence for similar processes in humans is limited. We also provide perspectives about how treatments can improve for future advancement of obesity treatment. Show less