Design of novel Xenopus GLP-1-based dual glucagon-like peptide 1 (GLP-1)/glucagon receptor agonists

Know your molecule: pharmacological characterization of drug candidates to enhance efficacy and reduce late-stage attrition

Despite advances in chemical, computational and biological sciences, the rate of attrition of drug candidates in clinical development is still high. A key point in the small-molecule discovery process that could provide opportunities to help address this challenge is the pharmacological characterization of hit and lead compounds, culminating in the selection of a drug candidate. Deeper characterization is increasingly important, because the 'quality' of drug efficacy, at least for G protein-coupled receptors (GPCRs), is now understood to be much more than activation of commonly evaluated pathways such as cAMP signalling, with many more 'efficacies' of ligands that could be harnessed therapeutically. Such characterization is being enabled by novel assays to characterize the complex behaviour of GPCRs, such as biased signalling and allosteric modulation, as well as advances in structural biology, such as cryo-electron microscopy. This article discusses key factors in the assessments of the pharmacology of hit and lead compounds in the context of GPCRs as a target class, highlighting opportunities to identify drug candidates with the potential to address limitations of current therapies and to improve the probability of them succeeding in clinical development.

Design and discovery of a highly potent ultralong-acting GLP-1 and glucagon co-agonist for attenuating renal fibrosis

The role of co-agonists of glucagon-like peptide-1 receptor (GLP-1R) and glucagon receptor (GCGR) in chronic kidney disease (CKD) remains unclear. Herein we found that GLP-1R and GCGR expression levels were lower in the kidneys of mice with CKD compared to healthy mice and were correlated with disease severity. Interestingly, GLP-1R or GCGR knockdown aggravated the progression of kidney injury in both diabetic db/db mice and non-diabetic mice undergoing unilateral ureteral obstruction (UUO). Based on the importance of GLP-1R and GCGR in CKD, we reported a novel monomeric peptide, 1907-B, with dual-agonism on both GLP-1R and GCGR. The data confirmed that 1907-B had a longer half-life than long-acting semaglutide in rats or cynomolgus monkeys (∼2-3 fold) and exhibited better therapeutic contribution to CKD than best-in-class monoagonists, semaglutide, or glucagon, in db/db mice and UUO mice. Various lock-of-function models, including selective pharmacological activation and genetic knockdown, confirmed that 1907-B's effects on ameliorating diabetic nephropathy in db/db mice, as well as inhibiting kidney fibrosis in UUO mice, were mediated through GLP-1 and glucagon signaling. These findings highlight that 1907-B, a novel GLP-1R and GCGR co-agonist, exerts multifactorial improvement in kidney injuries and is an effective and promising therapeutic option for CKD treatment.

Discovery of a Novel Glucagon-like Peptide-1 (GLP-1) Analogue from Bullfrog and Investigation of Its Potential for Designing GLP-1-Based Multiagonists

In this study, we aimed to discover novel GLP-1 analogues from natural sources. We investigated GLP-1 analogues from fish and amphibians, and bullfrog GLP-1 (bGLP-1) showed the highest potency. Starting with bGLP-1, we explored the structure-activity relationship and performed optimization and long-acting modifications, resulting in a potent analogue called 2f. Notably, 2f exhibited superior effects on food intake, glycemic control, and body weight compared to semaglutide. Furthermore, we explored the usefulness of bGLP-1 in designing GLP-1-based multiagonists. Using the bGLP-1 sequence, we designed novel dual GLP-1/glucagon receptor agonists and triple GLP-1/GIP/glucagon receptor agonists. The selected dual GLP-1/glucagon receptor agonist 3o and triple GLP-1/GIP/glucagon receptor agonist 4b exhibited significant therapeutic effects on lipid regulation, glycemic control, and body weight. Overall, our study highlights the potential of discovering potent GLP-1 receptor agonists from natural sources. Additionally, utilizing natural GLP-1 analogues for designing multiagonists presents a practical approach for developing antiobesity and antidiabetic agents.

Synergistic Combinations of Gut- and Pancreas-Hormone-Based Therapies: Advancements in Treatments for Metabolic Diseases

Metabolic diseases, such as obesity, type 2 diabetes mellitus (T2DM), cardiovascular disease, and liver disease, have become increasingly prevalent around the world. As an alternative to bariatric surgery, glucagon-like peptide 1 (GLP-1) receptor agonists have been at the forefront of weight loss medication to combat these metabolic complications. Recently, there has been an exciting rapid emergence of new weight loss medications that combine GLP-1 receptor (GLP-1R) agonists with other gut- and pancreatic-derived hormones, such as glucose-dependent insulinotropic polypeptide (GIP) and glucagon (GCG) receptor agonists. Dual-agonist (GLP-1/GIP and GLP-1/GCG) and tri-agonist (GLP-1/GIP/GCG) administration generally result in greater weight loss, reduction of blood sugar and lipid levels, restoration of tissue function, and improvement in whole-body substrate metabolism compared to when GLP-1R agonists are used alone. The aim of this review is to summarize the recent literature of both preclinical and clinical studies on how these emerging gut-peptide therapies further improve weight loss and metabolic health outcomes for various metabolic diseases.

Discovery of a potent and long-acting Xenopus GLP-1-based GLP-1/glucagon/Y2 receptor triple agonist

The combination of incretin-based therapies and PYY analogue has shown great potential for the treatment of type 2 diabetes (T2DM) and obesity. In this study we developed the first example of a unimolecular triple agonist peptide to simultaneously target GLP-1, glucagon and Y₂ receptors, aiming for superior weight loss and better glycemic control. The strategy for constructing such a unimolecular triple agonist peptide is the conjugation of the GLP-1R/GCGR dual-agonistic moiety and PYY moiety via maleimide-thiol specific reaction. A novel triple agonist peptide, 3b, was identified via stepwise structure optimization, long-acting modification and in vitro receptor screens. Peptide 3b exhibited potent and balanced GCGR and GLP-1R activities as well as potent and highly selective Y₂R activity. Peptide 3b potently reduced food intake without triggering nausea associated behavior in kaolin consumption and conditioned taste aversion assays. In diet induced obesity (DIO) mice, a lower dose of 3b achieved significantly better effects on lipid metabolism, body weight, and glycemic control than higher dose of GLP-1R mono-agonist, GLP-1R/GCGR dual agonist and GLP-1R/Y₂R dual agonist counterparts. Collectively, these data support the therapeutic potential of our GLP-1R/GCGR/Y₂R triple agonist 3b as a novel anti-obesity and anti-diabetic agent. Targeting GLP-1R, GCGR and Y₂R with unimolecular triple agonist peptide offers a route to develop new obesity and T2DM treatments.

Design of Xenopus GLP-1-Based Long-Acting Dual GLP-1/Y2 Receptor Agonists

GLP-1 receptor (GLP-1R) and neuropeptide Y₂ receptor (Y₂R) dual agonists have shown great potential to treat obesity and type 2 diabetes (T2DM). We developed a multitarget strategy to design monomeric agonists based on Xenopus GLP-1 (xGLP-1) and PYY_3-36 analogues with dual activation activities on GLP-1R and Y₂R. A novel peptide, 6q, was obtained via stepwise structure optimization and in vitro receptor screens. In db/db and diet-induced obesity (DIO) mice, 6q produced greater effects on long-term glycemic control and body weight reduction than GLP-1R and Y₂R monoagonist counterparts. Notably, in high-fat diet-induced nonalcoholic steatohepatitis (NASH) mice, 6q treatment significantly reduced hepatic triglyceride and total cholesterol levels and reversed hepatic steatosis compared with GLP-1R monoagonist (liraglutide) treatment. Collectively, these data support the therapeutic potential of our GLP-1R/Y₂R dual agonist 6q as a novel antidiabetic, antiobesity, and antisteatotic agent.

Discovery of once-weekly, peptide-based selective GLP-1 and cholecystokinin 2 receptors co-agonizts

A group of long-acting, peptide-based, and selective GLP-1R/CCK-2R dual agonizts were identified by rational design. Guided by sequence analysis, structural elements of the CCK-2R agonist moiety were engineered into the GLP-1R agonist Xenopus GLP-1, resulting in hybrid peptides with potent GLP-1R/CCK-2R dual activity. Further modifications with fatty acids resulted in novel metabolically stable peptides, among which 3d and 3 h showed potent GLP-1R and CCK-2R activation potencies and comparable stability to semaglutide. In food intake tests, 3d and 3 h also showed a potent reduction in food intake, superior to that of semaglutide. Moreover, the acute hypoglycemic and insulinotropic activities of 3d and 3 h were better than that of semaglutide and ZP3022. Importantly, the limited pica response following 3d and 3 h administration in SD rats preliminarily indicated that the food intake reduction effects of 3d and 3 h are independent of nausea/vomiting. In a 35-day study in db/db mice, every two days administration of 3d and 3 h increased islet areas and numbers, insulin contents, β-cell area, β-cell proliferation, as well as improved glucose tolerance, and decreased HbA1c, to a greater extent than ZP3022 and semaglutide. In a 21-day study in DIO mice, once-weekly administration of 3d and 3 h significantly induced body weight loss, improved glucose tolerance, and normalized lipid metabolism, to a greater extent than semaglutide. The current study showed the antidiabetic and antiobesity potentials of GLP-1R/CCK-2R dual agonizts that warrant further investigation.

A GLP-1/glucagon/CCK-2 receptors tri-agonist provides new therapy for obesity and diabetes

BACKGROUND AND PURPOSE

Glucagon-like peptide-1 receptor (GLP-1R) and glucagon receptor (GCGR) dual agonists have exerted promising therapeutic effects for the treatment of obesity and diabetes in clinical development. Moreover, GLP-1R and cholecystokinin 2 receptor (CCK-2R) dual agonists have been shown to restore pancreas function and improve glycemic control in many preclinical studies. In the present study, we describe for the first time that the beneficial effects of GLP-1R/GCGR and GLP-1R/CCK-2R dual agonists can be integrated into one peptide, resulting in significant anti-diabetes and anti-obesity effectiveness.

EXPERIMENTAL APPROACH

The in vitro potency of a novel GLP-1R/GCGR/CCK-2R tri-agonist (xGLP/GCG/gastrin) against GLP-1R, GCGR, CCK-1R and CCK-2R was determined on cells expressing the corresponding receptors by cAMP accumulation or ERK1/2 phosphorylation assays. The in vivo anti-diabetes and anti-obesity effects of xGLP/GCG/gastrin were studied in both db/db and diet induced obesity (DIO) mice.

KEY RESULTS

xGLP/GCG/gastrin was a potent and selective GLP-1R, GCGR, and CCK-2R tri-agonist. In DIO mice, the metabolic benefits of xGLP-1/GCG/gastrin such as reduction of body weight and hepatic lipid contents were significantly better than those of ZP3022 (GLP-1R/CCK-2R dual agonist) and liraglutide. In the short term study in db/db mice, xGLP/GCG/gastrin treatment exerted considerable effects on increasing islet numbers, islet areas, and insulin content. In the long-term treatment study in db/db mice, xGLP-1/GCG/gastrin displayed a significantly sustained improvement in glucose tolerance and glucose control compared with those of liraglutide, ZP3022, cotadutide (GLP-1R/GCGR dual agonist), and xGLP/GCG-15.

CONCLUSIONS AND IMPLICATIONS

These results demonstrate the therapeutic promise of xGLP-1/GCG/gastrin for obesity and diabetes.

Stapled, Long-Acting Xenopus GLP-1-Based Dual GLP-1/Glucagon Receptor Agonists with Potent Therapeutic Efficacy for Metabolic Disease

Novel peptidic glucagon receptor (GCGR) and glucagon-like peptide 1 receptor (GLP-1R) dual agonists are reported to have increased efficacy over GLP-1R monoagonists for the treatment of diabetes and obesity. We identified a novel Xenopus GLP-1-based dual GLP-1R/GCGR agonist (xGLP/GCG-13) designed with a proper activity ratio favoring the GLP-1R versus the GCGR. However, the clinical utility of xGLP/GCG-13 is limited by its short in vivo half-life. Starting from xGLP/GCG-13, dual Cys mutation was performed, followed by covalent side-chain stapling and serum albumin binder incorporation, resulting in a stabilized secondary structure, enhanced agonist potency at GLP-1R and GCGR, and improved stability. The lead peptide 2c (stapled xGLP/GCG-13 analogue with a palmitic acid albumin binder) exhibits balanced GLP-1R and GCGR activations and potent, long-lasting effects on in vivo glucose control. 2c was further explored pharmacologically in diet-induced obesity and db/db rodent models. Chronic administration of 2c potently induced body weight loss and hypoglycemic effects, improved glucose tolerance, increased energy expenditure, and normalized lipid metabolism and adiposity in relevant animal models. These results indicated that 2c has potential for development as a novel antidiabetic and/or antiobesity drug. Furthermore, we propose that the incorporation of a proper serum protein-binding motif into a di-Cys staple is an effective method for improving the stabilities and bioactivities of peptides. This approach is likely applicable to other therapeutic peptides, such as glucose-dependent insulin-tropic peptide receptor (GIPR) and GLP-1R dual agonists or GLP-1R/GCGR/GIPR triagonists.

Canonical transient receptor potential channels and their modulators: biology, pharmacology and therapeutic potentials

Canonical transient receptor potential channels (TRPCs) are nonselective, high calcium permeability cationic channels. The TRPCs family includes TRPC1, TRPC2, TRPC3, TRPC4, TRPC5, TRPC6, and TRPC7. These channels are widely expressed in the cardiovascular and nervous systems and exist in many other human tissues and cell types, playing several crucial roles in the human physiological and pathological processes. Hence, the emergence of TRPCs modulators can help investigate these channels’ applications in health and disease. It is worth noting that the TRPCs subfamilies have structural and functional similarities, which presents a significant difficulty in screening and discovering of TRPCs modulators. In the past few years, only a limited number of selective modulators of TRPCs were detected; thus, additional research on more potent and more selective TRPCs modulators is needed. The present review focuses on the striking desired therapeutic effects of TRPCs modulators, which provides intel on the structural modification of TRPCs modulators and further pharmacological research. Importantly, TRPCs modulators can significantly facilitate future studies of TRPCs and TRPCs related diseases.