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Xie S, Chen D, Cai Y, Xu L, Liao O, Jia X, Ji X, Chen H, Mao J, Cai J. Evaluating the efficacy of GIPR agonists on non-alcoholic fatty liver disease: A Mediation Mendelian Randomization Study. Dig Liver Dis 2024:S1590-8658(24)00725-4. [PMID: 38735797 DOI: 10.1016/j.dld.2024.04.022] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/06/2024] [Revised: 04/20/2024] [Accepted: 04/23/2024] [Indexed: 05/14/2024]
Abstract
OBJECTIVE Non-alcoholic fatty liver disease (NAFLD) is becoming the most common chronic liver disease worldwide while still lacks drugs for treatment or prevention. We aimed to investigate the causal role of glucose-dependent insulinotropic polypeptide receptor agonists (GIPRAs) on NAFLD and identify the mediated risk factors by which GIPRAs exert their therapeutic effects. METHODS Genetic proxies of GIPRAs were identified as cis-SNPs of GIPR associated with both the gene expression level and HbA1c and analyses including colocalization and linkage disequilibrium (LD) were performed for validation. We then performed two-sample two-step mendelian randomization to determine the causal effect of GIPRAs on NAFLD. RESULTS The MR analysis suggested genetic proxies of GIPRAs were causally associated with reduced risk of NAFLD (Odds ratio (OR): 0.46, 95 % confidence interval (95 % CI): 0.24-0.88, P = 0.02) and T2DM (OR: 0.10, 95 % CI: 0.07-0.13, P < 0.01). In addition, Mediation analysis showed evidence of indirect effect of GIPRAs on NAFLD via TRIG (0.88, [0.85-0.92], P < 0.01) and HDL-C (0.85, [0.80-0.90], P < 0.01). CONCLUSIONS Our study provided strong evidence to support the causal role of GIPRAs on reducing the risk of NAFLD probably through improving lipid metabolism, especially TG and HDL-C, providing guidance for future clinical trials.
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Affiliation(s)
- Siyuan Xie
- Department of Gastroenterology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, PR China
| | - Delong Chen
- Department of Cardiology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, PR China
| | - Yangke Cai
- Department of Gastroenterology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, PR China
| | - Liyi Xu
- Department of Gastroenterology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, PR China
| | - Oulan Liao
- Department of Gastroenterology, The Fourth Affiliated Hospital, Zhejiang University School of Medicine, Yiwu, Zhejiang Province, PR China
| | - Xuan Jia
- Department of Gastroenterology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, PR China
| | - Xiaowei Ji
- Department of Gastroenterology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, PR China
| | - Hanwen Chen
- Department of Gastroenterology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, PR China
| | - Jianshan Mao
- Department of Gastroenterology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, PR China.
| | - Jianting Cai
- Department of Gastroenterology, The Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, Zhejiang Province, PR China.
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Nicholls SJ, Bhatt DL, Buse JB, Prato SD, Kahn SE, Lincoff AM, McGuire DK, Nauck MA, Nissen SE, Sattar N, Zinman B, Zoungas S, Basile J, Bartee A, Miller D, Nishiyama H, Pavo I, Weerakkody G, Wiese RJ, D'Alessio D. Comparison of tirzepatide and dulaglutide on major adverse cardiovascular events in participants with type 2 diabetes and atherosclerotic cardiovascular disease: SURPASS-CVOT design and baseline characteristics. Am Heart J 2024; 267:1-11. [PMID: 37758044 DOI: 10.1016/j.ahj.2023.09.007] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/28/2023] [Revised: 09/11/2023] [Accepted: 09/16/2023] [Indexed: 10/03/2023]
Abstract
BACKGROUND Tirzepatide, a once-weekly GIP/GLP-1 receptor agonist, reduces blood glucose and body weight in people with type 2 diabetes. The cardiovascular (CV) safety and efficacy of tirzepatide have not been definitively assessed in a cardiovascular outcomes trial. METHODS Tirzepatide is being studied in a randomized, double-blind, active-controlled CV outcomes trial. People with type 2 diabetes aged ≥40 years, with established atherosclerotic CV disease, HbA1c ≥7% to ≤10.5%, and body mass index ≥25 kg/m2 were randomized 1:1 to once weekly subcutaneous injection of either tirzepatide up to 15 mg or dulaglutide 1.5 mg. The primary outcome is time to first occurrence of any major adverse cardiovascular event (MACE), defined as CV death, myocardial infarction, or stroke. The trial is event-driven and planned to continue until ≥1,615 participants experience an adjudication-confirmed component of MACE. The primary analysis is noninferiority for time to first MACE of tirzepatide vs dulaglutide by demonstrating an upper confidence limit <1.05, which will also confirm superiority vs a putative placebo, and also to determine whether tirzepatide produces a greater CV benefit than dulaglutide (superiority analysis). RESULTS Over 2 years, 13,299 people at 640 sites in 30 countries across all world regions were randomized. The mean age of randomized participants at baseline was 64.1 years, diabetes duration 14.7 years, HbA1c 8.4%, and BMI 32.6 kg/m2. Overall, 65.0% had coronary disease, of whom 47.3% reported prior myocardial infarction and 57.4% had prior coronary revascularization. 19.1% of participants had a prior stroke and 25.3% had peripheral artery disease. The trial is fully recruited and ongoing. CONCLUSION SURPASS-CVOT will provide definitive evidence as to the CV safety and efficacy of tirzepatide as compared with dulaglutide, a GLP-1 receptor agonist with established CV benefit.
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Affiliation(s)
- Stephen J Nicholls
- Victorian Heart Institute, Monash University, VIC, Melbourne, Australia.
| | - Deepak L Bhatt
- Mount Sinai Heart, Icahn School of Medicine at Mount Sinai Health System, New York, NY
| | - John B Buse
- University of North Carolina, Chapel Hill, NC
| | - Stefano Del Prato
- Department of Clinical and Experimental Medicine, Section of Metabolic Diseases and Diabetes, University of Pisa, Pisa, and Sant'Anna School of Advanced Studies, Pisa, Italy
| | - Steven E Kahn
- Division of Metabolism, Endocrinology and Nutrition, Department of Medicine, VA Puget Sound Health Care System and University of Washington, Seattle, WA
| | - A Michael Lincoff
- Cleveland Clinic Coordinating Center for Clinical Research (C5Research) and Department of Cardiovascular Medicine, Cleveland, OH
| | - Darren K McGuire
- University of Texas Southwestern Medical Center and Parkland Health and Hospital System, Dallas, TX
| | - Michael A Nauck
- Diabetes, Endocrinology and Metabolism Section, Department of Medicine I, St. Josef-Hospital, Katholisches Klinikum Bochum gGmbH, Ruhr University of Bochum, Bochum, Germany
| | - Steven E Nissen
- Cleveland Clinic Coordinating Center for Clinical Research (C5Research) and Department of Cardiovascular Medicine, Cleveland, OH
| | - Naveed Sattar
- School of Cardiovascular and Metabolic Health, University of Glasgow, United Kingdom
| | - Bernard Zinman
- University of Toronto, Lunenfeld-Tanenbaum Research Institute and Mount Sinai Hospital, Toronto, ON, Canada
| | - Sophia Zoungas
- Victorian Heart Institute, Monash University, VIC, Melbourne, Australia; School of Public Health and Preventive Medicine, Monash University, VIC, Melbourne, Australia
| | - Jan Basile
- Medical University of South Carolina, Ralph H. Johnson VA Medical Center, Charleston, SC
| | | | | | | | - Imre Pavo
- Eli Lilly and Company, Indianapolis, IN
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3
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Hammoud R, Drucker DJ. Beyond the pancreas: contrasting cardiometabolic actions of GIP and GLP1. Nat Rev Endocrinol 2023; 19:201-216. [PMID: 36509857 DOI: 10.1038/s41574-022-00783-3] [Citation(s) in RCA: 56] [Impact Index Per Article: 56.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 11/17/2022] [Indexed: 12/14/2022]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP1) exhibit incretin activity, meaning that they potentiate glucose-dependent insulin secretion. The emergence of GIP receptor (GIPR)-GLP1 receptor (GLP1R) co-agonists has fostered growing interest in the actions of GIP and GLP1 in metabolically relevant tissues. Here, we update concepts of how these hormones act beyond the pancreas. The actions of GIP and GLP1 on liver, muscle and adipose tissue, in the control of glucose and lipid homeostasis, are discussed in the context of plausible mechanisms of action. Both the GIPR and GLP1R are expressed in the central nervous system, wherein receptor activation produces anorectic effects enabling weight loss. In preclinical studies, GIP and GLP1 reduce atherosclerosis. Furthermore, GIPR and GLP1R are expressed within the heart and immune system, and GLP1R within the kidney, revealing putative mechanisms linking GIP and GLP1R agonism to cardiorenal protection. We interpret the clinical and mechanistic data obtained for different agents that enable weight loss and glucose control for the treatment of obesity and type 2 diabetes mellitus, respectively, by activating or blocking GIPR signalling, including the GIPR-GLP1R co-agonist tirzepatide, as well as the GIPR antagonist-GLP1R agonist AMG-133. Collectively, we update translational concepts of GIP and GLP1 action, while highlighting gaps, areas of uncertainty and controversies meriting ongoing investigation.
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Affiliation(s)
- Rola Hammoud
- Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt Sinai Hospital, University of Toronto, Toronto, Ontario, Canada
| | - Daniel J Drucker
- Department of Medicine, Lunenfeld-Tanenbaum Research Institute, Mt Sinai Hospital, University of Toronto, Toronto, Ontario, Canada.
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Burgess S, Mason AM, Grant AJ, Slob EAW, Gkatzionis A, Zuber V, Patel A, Tian H, Liu C, Haynes WG, Hovingh GK, Knudsen LB, Whittaker JC, Gill D. Using genetic association data to guide drug discovery and development: Review of methods and applications. Am J Hum Genet 2023; 110:195-214. [PMID: 36736292 PMCID: PMC9943784 DOI: 10.1016/j.ajhg.2022.12.017] [Citation(s) in RCA: 30] [Impact Index Per Article: 30.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023] Open
Abstract
Evidence on the validity of drug targets from randomized trials is reliable but typically expensive and slow to obtain. In contrast, evidence from conventional observational epidemiological studies is less reliable because of the potential for bias from confounding and reverse causation. Mendelian randomization is a quasi-experimental approach analogous to a randomized trial that exploits naturally occurring randomization in the transmission of genetic variants. In Mendelian randomization, genetic variants that can be regarded as proxies for an intervention on the proposed drug target are leveraged as instrumental variables to investigate potential effects on biomarkers and disease outcomes in large-scale observational datasets. This approach can be implemented rapidly for a range of drug targets to provide evidence on their effects and thus inform on their priority for further investigation. In this review, we present statistical methods and their applications to showcase the diverse opportunities for applying Mendelian randomization in guiding clinical development efforts, thus enabling interventions to target the right mechanism in the right population group at the right time. These methods can inform investigators on the mechanisms underlying drug effects, their related biomarkers, implications for the timing of interventions, and the population subgroups that stand to gain the most benefit. Most methods can be implemented with publicly available data on summarized genetic associations with traits and diseases, meaning that the only major limitations to their usage are the availability of appropriately powered studies for the exposure and outcome and the existence of a suitable genetic proxy for the proposed intervention.
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Affiliation(s)
- Stephen Burgess
- MRC Biostatistics Unit, School of Clinical Medicine, University of Cambridge, Cambridge, UK; Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.
| | - Amy M Mason
- Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK
| | - Andrew J Grant
- MRC Biostatistics Unit, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Eric A W Slob
- MRC Biostatistics Unit, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | | | - Verena Zuber
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK; MRC Centre for Environment and Health, School of Public Health, Imperial College London, London, UK; UK Dementia Research Institute at Imperial College, Imperial College London, London, UK
| | - Ashish Patel
- MRC Biostatistics Unit, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Haodong Tian
- MRC Biostatistics Unit, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Cunhao Liu
- MRC Biostatistics Unit, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - William G Haynes
- Novo Nordisk Research Centre Oxford, Novo Nordisk, Oxford, UK; Radcliffe Department of Medicine, University of Oxford, Oxford, UK
| | - G Kees Hovingh
- Department of Vascular Medicine, Academic Medical Center, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, the Netherlands; Global Chief Medical Office, Novo Nordisk, Copenhagen, Denmark
| | - Lotte Bjerre Knudsen
- Chief Scientific Advisor Office, Research and Early Development, Novo Nordisk, Copenhagen, Denmark
| | - John C Whittaker
- MRC Biostatistics Unit, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Dipender Gill
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK; Chief Scientific Advisor Office, Research and Early Development, Novo Nordisk, Copenhagen, Denmark
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Nauck MA, D‘Alessio DA. Tirzepatide, a dual GIP/GLP-1 receptor co-agonist for the treatment of type 2 diabetes with unmatched effectiveness regrading glycaemic control and body weight reduction. Cardiovasc Diabetol 2022; 21:169. [PMID: 36050763 PMCID: PMC9438179 DOI: 10.1186/s12933-022-01604-7] [Citation(s) in RCA: 70] [Impact Index Per Article: 35.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/11/2022] [Accepted: 08/19/2022] [Indexed: 11/29/2022] Open
Abstract
Tirzepatide is the first dual GIP/GLP-1 receptor co-agonist approved for the treatment of type 2 diabetes in the USA, Europe, and the UAE. Tirzepatide is an acylated peptide engineered to activate the GIP and GLP-1 receptors, key mediators of insulin secretion that are also expressed in regions of the brain that regulate food intake. Five clinical trials in type 2-diabetic subjects (SURPASS 1–5) have shown that tirzepatide at 5–15 mg per week reduces both HbA1c (1.24 to 2.58%) and body weight (5.4–11.7 kg) by amounts unprecedented for a single agent. A sizable proportion of patients (23.0 to 62.4%) reached an HbA1c of < 5.7% (which is the upper limit of the normal range indicating normoglycaemia), and 20.7 to 68.4% lost more than 10% of their baseline body weight. Tirzepatide was significantly more effective in reducing HbA1c and body weight than the selective GLP-1 RA semaglutide (1.0 mg per week), and titrated basal insulin. Adverse events related to tirzepatide were similar to what has been reported for selective GLP-1RA, mainly nausea, vomiting, diarrhoea, and constipation, that were more common at higher doses. Cardiovascular events have been adjudicated across the whole study program, and MACE-4 (nonfatal myocardial infarction, non-fatal stroke, cardiovascular death and hospital admission for angina) events tended to be reduced over up to a 2 year-period, albeit with low numbers of events. For none of the cardiovascular events analysed (MACE-4, or its components) was a hazard ratio > 1.0 vs. pooled comparators found in a meta-analysis covering the whole clinical trial program, and the upper bounds of the confidence intervals for MACE were < 1.3, fulfilling conventional definitions of cardiovascular safety. Tirzepatide was found to improve insulin sensitivity and insulin secretory responses to a greater extent than semaglutide, and this was associated with lower prandial insulin and glucagon concentrations. Both drugs caused similar reductions in appetite, although tirzepatide caused greater weight loss. While the clinical effects of tirzepatide have been very encouraging, important questions remain as to the mechanism of action. While GIP reduces food intake and body weight in rodents, these effects have not been demonstrated in humans. Moreover, it remains to be shown that GIPR agonism can improve insulin secretion in type 2 diabetic patients who have been noted in previous studies to be unresponsive to GIP. Certainly, the apparent advantage of tirzepatide, a dual incretin agonist, over GLP-1RA will spark renewed interest in the therapeutic potential of GIP in type 2 diabetes, obesity and related co-morbidities.
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6
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Pujadas G, Baggio LL, Kaur KD, McLean BA, Cao X, Drucker DJ. Genetic disruption of the Gipr in Apoe -/- mice promotes atherosclerosis. Mol Metab 2022; 65:101586. [PMID: 36055579 PMCID: PMC9478451 DOI: 10.1016/j.molmet.2022.101586] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/25/2022] [Revised: 08/17/2022] [Accepted: 08/26/2022] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVE The gut hormone glucose-dependent insulinotropic polypeptide (GIP) stimulates beta cell function and improves glycemia through its incretin actions. GIP also regulates endothelial function and suppresses adipose tissue inflammation through control of macrophage activity. Activation of the GIP receptor (GIPR) attenuates experimental atherosclerosis and inflammation in mice, however whether loss of GIPR signaling impacts the development of atherosclerosis is uncertain. METHODS Atherosclerosis and related metabolic phenotypes were studied in Apoe-/-:Gipr-/- mice and in Gipr+/+ and Gipr-/- mice treated with an adeno-associated virus expressing PCSK9 (AAV-PCSK9). Bone marrow transplantation (BMT) studies were carried out using donor marrow from Apoe-/-:Gipr-/-and Apoe-/-:Gipr+/+mice transplanted into Apoe-/-:Gipr-/- recipient mice. Experimental endpoints included the extent of aortic atherosclerosis and inflammation, body weight, glucose tolerance, and circulating lipid levels, the proportions and subsets of circulating leukocytes, and tissue gene expression profiles informing lipid and glucose metabolism, and inflammation. RESULTS Body weight was lower, circulating myeloid cells were reduced, and glucose tolerance was not different, however, aortic atherosclerosis was increased in Apoe-/-:Gipr-/- mice and trended higher in Gipr-/- mice with atherosclerosis induced by AAV-PCSK9. Levels of mRNA transcripts for genes contributing to inflammation were increased in the aortae of Apoe-/-:Gipr-/- mice and expression of a subset of inflammation-related hepatic genes were increased in Gipr-/- mice treated with AAV-PCSK9. BMT experiments did not reveal marked atherosclerosis, failing to implicate bone marrow derived GIPR + cells in the control of atherosclerosis or aortic inflammation. CONCLUSIONS Loss of the Gipr in mice results in increased aortic atherosclerosis and enhanced inflammation in aorta and liver, despite reduced weight gain and preserved glucose homeostasis. These findings extend concepts of GIPR in the suppression of inflammation-related pathophysiology beyond its classical incretin role in the control of metabolism.
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Affiliation(s)
| | | | | | | | | | - Daniel J. Drucker
- Corresponding author. LTRI, Mt. Sinai Hospital 600 University Ave Mailbox 39, TCP5-1004 Toronto ON M5G 1X5 Canada.
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Knerr PJ, Mowery SA, Douros JD, Premdjee B, Hjøllund KR, He Y, Kruse Hansen AM, Olsen AK, Perez-Tilve D, DiMarchi RD, Finan B. Next generation GLP-1/GIP/glucagon triple agonists normalize body weight in obese mice. Mol Metab 2022; 63:101533. [PMID: 35809773 PMCID: PMC9305623 DOI: 10.1016/j.molmet.2022.101533] [Citation(s) in RCA: 48] [Impact Index Per Article: 24.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/25/2022] [Revised: 06/18/2022] [Accepted: 06/18/2022] [Indexed: 12/19/2022] Open
Abstract
Objective Pharmacological strategies that engage multiple mechanisms-of-action have demonstrated synergistic benefits for metabolic disease in preclinical models. One approach, concurrent activation of the glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic peptide (GIP), and glucagon (Gcg) receptors (i.e. triagonism), combines the anorectic and insulinotropic activities of GLP-1 and GIP with the energy expenditure effect of glucagon. While the efficacy of triagonism in preclinical models is known, the relative contribution of GcgR activation remains unassessed. This work aims to addresses that central question. Methods Herein, we detail the design of unimolecular peptide triagonists with an empirically optimized receptor potency ratio. These optimized peptide triagonists employ a protraction strategy permitting once-weekly human dosing. Additionally, we assess the effects of these peptides on weight-reduction, food intake, glucose control, and energy expenditure in an established DIO mouse model compared to clinically relevant GLP-1R agonists (e.g. semaglutide) and dual GLP-1R/GIPR agonists (e.g. tirzepatide). Results Optimized triagonists normalize body weight in DIO mice and enhance energy expenditure in a manner superior to that of GLP-1R mono-agonists and GLP-1R/GIPR co-agonists. Conclusions These pre-clinical data suggest unimolecular poly-pharmacology as an effective means to target multiple mechanisms contributing to obesity and further implicate GcgR activation as the differentiating factor between incretin receptor mono- or dual-agonists and triagonists. Details the design of unimolecular peptide triagonists for GLP-1R/GIPR/GCGR. Optimal weight-loss is achieved when receptor potency ratio is weighted toward GCGR vs GLP-1R or GIPR. These agonists are protracted for once-weekly human dosing. Optimized triagonists normalizes body weight & enhance energy expenditure in mice. Efficacy of optimized triagonists is superior to GLP-1R & GLP-1R/GIPR agonists.
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Affiliation(s)
- Patrick J Knerr
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA
| | | | | | | | | | - Yantao He
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA
| | | | | | - Diego Perez-Tilve
- Department of Pharmacology and Systems Physiology, University of Cincinnati College of Medicine, Cincinnati, OH, USA
| | | | - Brian Finan
- Novo Nordisk Research Center Indianapolis, Indianapolis, IN, USA.
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Zuber V, Grinberg NF, Gill D, Manipur I, Slob EAW, Patel A, Wallace C, Burgess S. Combining evidence from Mendelian randomization and colocalization: Review and comparison of approaches. Am J Hum Genet 2022; 109:767-782. [PMID: 35452592 PMCID: PMC7612737 DOI: 10.1016/j.ajhg.2022.04.001] [Citation(s) in RCA: 102] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022] Open
Abstract
Mendelian randomization and colocalization are two statistical approaches that can be applied to summarized data from genome-wide association studies (GWASs) to understand relationships between traits and diseases. However, despite similarities in scope, they are different in their objectives, implementation, and interpretation, in part because they were developed to serve different scientific communities. Mendelian randomization assesses whether genetic predictors of an exposure are associated with the outcome and interprets an association as evidence that the exposure has a causal effect on the outcome, whereas colocalization assesses whether two traits are affected by the same or distinct causal variants. When considering genetic variants in a single genetic region, both approaches can be performed. While a positive colocalization finding typically implies a non-zero Mendelian randomization estimate, the reverse is not generally true: there are several scenarios which would lead to a non-zero Mendelian randomization estimate but lack evidence for colocalization. These include the existence of distinct but correlated causal variants for the exposure and outcome, which would violate the Mendelian randomization assumptions, and a lack of strong associations with the outcome. As colocalization was developed in the GWAS tradition, typically evidence for colocalization is concluded only when there is strong evidence for associations with both traits. In contrast, a non-zero estimate from Mendelian randomization can be obtained despite only nominally significant genetic associations with the outcome at the locus. In this review, we discuss how the two approaches can provide complementary information on potential therapeutic targets.
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Affiliation(s)
- Verena Zuber
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK; MRC Centre for Environment and Health, School of Public Health, Imperial College London, London, UK; UK Dementia Research Institute at Imperial College, Imperial College London, London, UK
| | | | - Dipender Gill
- Department of Epidemiology and Biostatistics, School of Public Health, Imperial College London, London, UK; Clinical Pharmacology and Therapeutics Section, Institute of Medical and Biomedical Education and Institute for Infection and Immunity, St George's, University of London, London, UK; Clinical Pharmacology Group, Pharmacy and Medicines Directorate, St George's University Hospitals NHS Foundation Trust, London, UK; Genetics Department, Novo Nordisk Research Centre Oxford, Oxford, UK
| | - Ichcha Manipur
- Cambridge Institute of Therapeutic Immunology & Infectious Disease, University of Cambridge, Cambridge, UK; Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge, UK
| | - Eric A W Slob
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | - Ashish Patel
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | - Chris Wallace
- Cambridge Institute of Therapeutic Immunology & Infectious Disease, University of Cambridge, Cambridge, UK; Department of Medicine, School of Clinical Medicine, University of Cambridge, Cambridge, UK; MRC Biostatistics Unit, University of Cambridge, Cambridge, UK
| | - Stephen Burgess
- MRC Biostatistics Unit, University of Cambridge, Cambridge, UK; Cardiovascular Epidemiology Unit, Department of Public Health and Primary Care, University of Cambridge, Cambridge, UK.
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