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Himuro M, Wakabayashi Y, Taguchi T, Katahira T, Suzuki L, Iida H, Ogihara T, Nishida Y, Sasaki S, Lynn FC, Hiraoka Y, Oshima S, Okamoto R, Fujitani Y, Watada H, Miyatsuka T. Novel time-resolved reporter mouse reveals spatial and transcriptional heterogeneity during alpha cell differentiation. Diabetologia 2024; 67:156-169. [PMID: 37870650 DOI: 10.1007/s00125-023-06028-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2023] [Accepted: 08/25/2023] [Indexed: 10/24/2023]
Abstract
AIMS/HYPOTHESIS Glucagon-expressing pancreatic alpha cells have attracted much attention for their plasticity to transdifferentiate into insulin-producing beta cells; however, it remains unclear precisely when, and from where, alpha cells emerge and what regulates alpha cell fate. We therefore explored the spatial and transcriptional heterogeneity of alpha cell differentiation using a novel time-resolved reporter system. METHODS We established the mouse model, 'Gcg-Timer', in which newly generated alpha cells can be distinguished from more-differentiated cells by their fluorescence. Fluorescence imaging and transcriptome analysis were performed with Gcg-Timer mice during the embryonic and postnatal stages. RESULTS Fluorescence imaging and flow cytometry demonstrated that green fluorescence-dominant cells were present in Gcg-Timer mice at the embryonic and neonatal stages but not after 1 week of age, suggesting that alpha cell neogenesis occurs during embryogenesis and early neonatal stages under physiological conditions. Transcriptome analysis of Gcg-Timer embryos revealed that the mRNAs related to angiogenesis were enriched in newly generated alpha cells. Histological analysis revealed that some alpha cells arise close to the pancreatic ducts, whereas the others arise away from the ducts and adjacent to the blood vessels. Notably, when the glucagon signal was suppressed by genetic ablation or by chemicals, such as neutralising glucagon antibody, green-dominant cells emerged again in adult mice. CONCLUSIONS/INTERPRETATION Novel time-resolved analysis with Gcg-Timer reporter mice uncovered spatiotemporal features of alpha cell neogenesis that will enhance our understanding of cellular identity and plasticity within the islets. DATA AVAILABILITY Raw and processed RNA sequencing data for this study has been deposited in the Gene Expression Omnibus under accession number GSE229090.
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Affiliation(s)
- Miwa Himuro
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yuka Wakabayashi
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Tomomi Taguchi
- Department of Endocrinology, Diabetes and Metabolism, Kitasato University School of Medicine, Sagamihara, Japan
| | - Takehiro Katahira
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Luka Suzuki
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Hitoshi Iida
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Takeshi Ogihara
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yuya Nishida
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Shugo Sasaki
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada
- Department of Metabolic Medicine, Osaka University Graduate School of Medicine, Osaka, Japan
| | - Francis C Lynn
- Diabetes Research Group, BC Children's Hospital Research Institute, Vancouver, BC, Canada
| | - Yuichi Hiraoka
- Laboratory of Genome Editing for Biomedical Research, Medical Research Institute, Tokyo Medical and Dental University, Tokyo, Japan
| | - Shigeru Oshima
- Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Ryuichi Okamoto
- Department of Gastroenterology and Hepatology, Tokyo Medical and Dental University, Tokyo, Japan
| | - Yoshio Fujitani
- Laboratory of Developmental Biology & Metabolism, Institute for Molecular & Cellular Regulation, Gunma University, Maebashi, Japan
| | - Hirotaka Watada
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan.
- Center for Identification of Diabetic Therapeutic Targets, Juntendo University Graduate School of Medicine, Tokyo, Japan.
| | - Takeshi Miyatsuka
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan.
- Department of Endocrinology, Diabetes and Metabolism, Kitasato University School of Medicine, Sagamihara, Japan.
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Cui X, Feng J, Wei T, Zhang L, Lang S, Yang K, Yang J, Liu J, Sterr M, Lickert H, Wei R, Hong T. Pancreatic alpha cell glucagon-liver FGF21 axis regulates beta cell regeneration in a mouse model of type 2 diabetes. Diabetologia 2023; 66:535-550. [PMID: 36331598 PMCID: PMC9892158 DOI: 10.1007/s00125-022-05822-2] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/15/2022] [Accepted: 09/14/2022] [Indexed: 11/06/2022]
Abstract
AIMS/HYPOTHESIS Glucagon receptor (GCGR) antagonism ameliorates hyperglycaemia and promotes beta cell regeneration in mouse models of type 2 diabetes. However, the underlying mechanisms remain unclear. The present study aimed to investigate the mechanism of beta cell regeneration induced by GCGR antagonism in mice. METHODS The db/db mice and high-fat diet (HFD)+streptozotocin (STZ)-induced mice with type 2 diabetes were treated with antagonistic GCGR monoclonal antibody (mAb), and the metabolic variables and islet cell quantification were evaluated. Plasma cytokine array and liver RNA sequencing data were used to screen possible mediators, including fibroblast growth factor 21 (FGF21). ELISA, quantitative RT-PCR and western blot were applied to verify FGF21 change. Blockage of FGF21 signalling by FGF21-neutralising antibody (nAb) was used to clarify whether FGF21 was involved in the effects of GCGR mAb on the expression of beta cell identity-related genes under plasma-conditional culture and hepatocyte co-culture conditions. FGF21 nAb-treated db/db mice, systemic Fgf21-knockout (Fgf21-/-) diabetic mice and hepatocyte-specific Fgf21-knockout (Fgf21Hep-/-) diabetic mice were used to reveal the involvement of FGF21 in beta cell regeneration. A BrdU tracing study was used to analyse beta cell proliferation in diabetic mice treated with GCGR mAb. RESULTS GCGR mAb treatment improved blood glucose control, and increased islet number (db/db 1.6±0.1 vs 0.8±0.1 per mm2, p<0.001; HFD+STZ 1.2±0.1 vs 0.5±0.1 per mm2, p<0.01) and area (db/db 2.5±0.2 vs 1.2±0.2%, p<0.001; HFD+STZ 1.0±0.1 vs 0.3±0.1%, p<0.01) in diabetic mice. The plasma cytokine array and liver RNA sequencing data showed that FGF21 levels in plasma and liver were upregulated by GCGR antagonism. The GCGR mAb induced upregulation of plasma FGF21 levels (db/db 661.5±40.0 vs 466.2±55.7 pg/ml, p<0.05; HFD+STZ 877.0±106.8 vs 445.5±54.0 pg/ml, p<0.05) and the liver levels of Fgf21 mRNA (db/db 3.2±0.5 vs 1.8±0.1, p<0.05; HFD+STZ 2.0±0.3 vs 1.0±0.2, p<0.05) and protein (db/db 2.0±0.2 vs 1.4±0.1, p<0.05; HFD+STZ 1.6±0.1 vs 1.0±0.1, p<0.01). Exposure to plasma or hepatocytes from the GCGR mAb-treated mice upregulated the mRNA levels of characteristic genes associated with beta cell identity in cultured mouse islets and a beta cell line, and blockage of FGF21 activity by an FGF21 nAb diminished this upregulation. Notably, the effects of increased beta cell number induced by GCGR mAb were attenuated in FGF21 nAb-treated db/db mice, Fgf21-/- diabetic mice and Fgf21Hep-/- diabetic mice. Moreover, GCGR mAb treatment enhanced beta cell proliferation in the two groups of diabetic mice, and this effect was weakened in Fgf21-/- and Fgf21Hep-/- mice. CONCLUSIONS/INTERPRETATION Our findings demonstrate that liver-derived FGF21 is involved in the GCGR antagonism-induced beta cell regeneration in a mouse model of type 2 diabetes.
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Affiliation(s)
- Xiaona Cui
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
- Clinical Stem Research Cell Center, Peking University Third Hospital, Beijing, China
| | - Jin Feng
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
- Institute of Diabetes and Regeneration Research, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- School of Medicine, Technical University of Munich, Munich, Germany
| | - Tianjiao Wei
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
- Clinical Stem Research Cell Center, Peking University Third Hospital, Beijing, China
| | - Linxi Zhang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
| | - Shan Lang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
| | - Kun Yang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
- Clinical Stem Research Cell Center, Peking University Third Hospital, Beijing, China
| | - Jin Yang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
- Clinical Stem Research Cell Center, Peking University Third Hospital, Beijing, China
| | - Junling Liu
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China
| | - Michael Sterr
- Institute of Diabetes and Regeneration Research, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- School of Medicine, Technical University of Munich, Munich, Germany
| | - Heiko Lickert
- Institute of Diabetes and Regeneration Research, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- School of Medicine, Technical University of Munich, Munich, Germany
| | - Rui Wei
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China.
- Clinical Stem Research Cell Center, Peking University Third Hospital, Beijing, China.
| | - Tianpei Hong
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing, China.
- Clinical Stem Research Cell Center, Peking University Third Hospital, Beijing, China.
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3
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Importance of multiple endocrine cell types in islet organoids for type 1 diabetes treatment. Transl Res 2022; 250:68-83. [PMID: 35772687 DOI: 10.1016/j.trsl.2022.06.014] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/17/2022] [Revised: 06/08/2022] [Accepted: 06/21/2022] [Indexed: 11/21/2022]
Abstract
Almost 50 years ago, scientists developed the bi-hormonal abnormality hypothesis, stating that diabetes is not caused merely by the impaired insulin signaling. Instead, the presence of inappropriate level of glucagon is a prerequisite for the development of type 1 diabetes (T1D). It is widely understood that the hormones insulin and glucagon, secreted by healthy β and α cells respectively, operate in a negative feedback loop to maintain the body's blood sugar levels. Despite this fact, traditional T1D treatments rely solely on exogenous insulin injections. Furthermore, research on cell-based therapies and stem-cell derived tissues tends to focus on the replacement of β cells alone. In vivo, the pancreas is made up of 4 major endocrine cell types, that is, insulin-producing β cells, glucagon-producing α cells, somatostatin-producing δ cells, and pancreatic polypeptide-producing γ cells. These distinct cell types are involved synergistically in regulating islet functions. Therefore, it is necessary to produce a pancreatic islet organoid in vitro consisting of all these cell types that adequately replaces the function of the native islets. In this review, we describe the unique function of each pancreatic endocrine cell type and their interactions contributing to the maintenance of normoglycemia. Furthermore, we detail current sources of whole islets and techniques for their long-term expansion and culture. In addition, we highlight a vast potential of the pancreatic islet organoids for transplantation and diabetes research along with updated new approaches for successful transplantation using stem cell-derived islet organoids.
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Kang Q, Zheng J, Jia J, Xu Y, Bai X, Chen X, Zhang XK, Wong FS, Zhang C, Li M. Disruption of the glucagon receptor increases glucagon expression beyond α-cell hyperplasia in zebrafish. J Biol Chem 2022; 298:102665. [PMID: 36334626 PMCID: PMC9719020 DOI: 10.1016/j.jbc.2022.102665] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/27/2022] [Revised: 10/24/2022] [Accepted: 10/26/2022] [Indexed: 11/11/2022] Open
Abstract
The glucagon receptor (GCGR) is a potential target for diabetes therapy. Several emerging GCGR antagonism-based therapies are under preclinical and clinical development. However, GCGR antagonism, as well as genetically engineered GCGR deficiency in animal models, are accompanied by α-cell hyperplasia and hyperglucagonemia, which may limit the application of GCGR antagonism. To better understand the physiological changes in α cells following GCGR disruption, we performed single cell sequencing of α cells isolated from control and gcgr-/- (glucagon receptor deficient) zebrafish. Interestingly, beyond the α-cell hyperplasia, we also found that the expression of gcga, gcgb, pnoca, and several glucagon-regulatory transcription factors were dramatically increased in one cluster of gcgr-/- α cells. We further confirmed that glucagon mRNA was upregulated in gcgr-/- animals by in situ hybridization and that glucagon promoter activity was increased in gcgr-/-;Tg(gcga:GFP) reporter zebrafish. We also demonstrated that gcgr-/- α cells had increased glucagon protein levels and increased granules after GCGR disruption. Intriguingly, the increased mRNA and protein levels could be suppressed by treatment with high-level glucose or knockdown of the pnoca gene. In conclusion, these data demonstrated that GCGR deficiency not only induced α-cell hyperplasia but also increased glucagon expression in α cells, findings which provide more information about physiological changes in α-cells when the GCGR is disrupted.
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Affiliation(s)
- Qi Kang
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen, China; Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
| | - Jihong Zheng
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Jianxin Jia
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen, China; Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
| | - Ying Xu
- Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Xuanxuan Bai
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen, China; Fundamental Research Center, Shanghai YangZhi Rehabilitation Hospital (Shanghai Sunshine Rehabilitation Center), School of Life Sciences and Technology, Tongji University, Shanghai, China
| | - Xinhua Chen
- Key Laboratory of Biotechnology of Fujian Province, Institute of Oceanology, Fujian Agriculture and Forestry University, Fuzhou, China
| | - Xiao-Kun Zhang
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen, China; Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China
| | - F Susan Wong
- Division of Infection and Immunity, Cardiff University School of Medicine, Cardiff, UK
| | - Chao Zhang
- Department of Plastic and Reconstructive Surgery, Shanghai Ninth People's Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai, China.
| | - Mingyu Li
- School of Pharmaceutical Sciences and School of Life Sciences, Xiamen University, Xiamen, China; Fujian Provincial Key Laboratory of Innovative Drug Target Research, School of Pharmaceutical Sciences, Xiamen University, Xiamen, China.
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5
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Elmelund E, Galsgaard KD, Johansen CD, Trammell SA, Bomholt AB, Winther-Sørensen M, Hunt JE, Sørensen CM, Kruse T, Lau JF, Grevengoed TJ, Holst JJ, Wewer Albrechtsen NJ. Opposing effects of chronic glucagon receptor agonism and antagonism on amino acids, hepatic gene expression, and alpha cells. iScience 2022; 25:105296. [PMID: 36325048 PMCID: PMC9618771 DOI: 10.1016/j.isci.2022.105296] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2022] [Revised: 08/29/2022] [Accepted: 09/30/2022] [Indexed: 01/09/2023] Open
Abstract
The pancreatic hormone, glucagon, is known to regulate hepatic glucose production, but recent studies suggest that its regulation of hepatic amino metabolism is equally important. Here, we show that chronic glucagon receptor activation with a long-acting glucagon analog increases amino acid catabolism and ureagenesis and causes alpha cell hypoplasia in female mice. Conversely, chronic glucagon receptor inhibition with a glucagon receptor antibody decreases amino acid catabolism and ureagenesis and causes alpha cell hyperplasia and beta cell loss. These effects were associated with the transcriptional regulation of hepatic genes related to amino acid uptake and catabolism and by the non-transcriptional modulation of the rate-limiting ureagenesis enzyme, carbamoyl phosphate synthetase-1. Our results support the importance of glucagon receptor signaling for amino acid homeostasis and pancreatic islet integrity in mice and provide knowledge regarding the long-term consequences of chronic glucagon receptor agonism and antagonism. Glucagon receptor agonism increases amino acid catabolism and hepatic CPS-1 activity Glucagon receptor signaling regulates the number of pancreatic alpha cells Glucagon regulates the hepatic transcription of genes involved in amino acid metabolism
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Affiliation(s)
- Emilie Elmelund
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Katrine D. Galsgaard
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Christian D. Johansen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Samuel A.J. Trammell
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Anna B. Bomholt
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Marie Winther-Sørensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Jenna E. Hunt
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Charlotte M. Sørensen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Thomas Kruse
- Novo Nordisk A/S, Research Chemistry, Novo Nordisk Park, 2760 Måløv, Denmark
| | - Jesper F. Lau
- Novo Nordisk A/S, Research Chemistry, Novo Nordisk Park, 2760 Måløv, Denmark
| | - Trisha J. Grevengoed
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Jens J. Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Nicolai J. Wewer Albrechtsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Clinical Biochemistry, Bispebjerg & Frederiksberg Hospitals, University of Copenhagen, 2400 Bispebjerg, Denmark
- Corresponding author
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6
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Pettus J, Boeder SC, Christiansen MP, Denham DS, Bailey TS, Akturk HK, Klaff LJ, Rosenstock J, Cheng MHM, Bode BW, Bautista ED, Xu R, Yan H, Thai D, Garg SK, Klein S. Glucagon receptor antagonist volagidemab in type 1 diabetes: a 12-week, randomized, double-blind, phase 2 trial. Nat Med 2022; 28:2092-2099. [PMID: 36192552 PMCID: PMC9872851 DOI: 10.1038/s41591-022-02011-x] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 08/15/2022] [Indexed: 01/26/2023]
Abstract
Hyperglucagonemia contributes to hyperglycemia in patients with type 1 diabetes (T1D); however, novel therapeutics that block glucagon action could improve glycemic control. This phase 2 study evaluated the safety and efficacy of volagidemab, an antagonistic monoclonal glucagon receptor (GCGR) antibody, as an adjunct to insulin therapy in adults with T1D. The primary endpoint was change in daily insulin use at week 12. Secondary endpoints included changes in hemoglobin A1c (HbA1c) at week 13, in average daily blood glucose concentration and time within target range as assessed by continuous blood glucose monitoring (CGM) and seven-point glucose profile at week 12, incidence of hypoglycemic events, the proportion of subjects who achieve HbA1c reduction of ≥0.4%, volagidemab drug concentrations and incidence of anti-drug antibodies. Eligible participants (n = 79) were randomized to receive weekly subcutaneous injections of placebo, 35 mg volagidemab or 70 mg volagidemab. Volagidemab produced a reduction in total daily insulin use at week 12 (35 mg volagidemab: -7.59 units (U) (95% confidence interval (CI) -11.79, -3.39; P = 0.040 versus placebo); 70 mg volagidemab: -6.64 U (95% CI -10.99, -2.29; P = 0.084 versus placebo); placebo: -1.27 U (95% CI -5.4, 2.9)) without meeting the prespecified significance level (P < 0.025). At week 13, the placebo-corrected reduction in HbA1c percentage was -0.53 (95% CI -0.89 to -0.17, nominal P = 0.004) in the 35 mg volagidemab group and -0.49 (95% CI -0.85 to -0.12, nominal P = 0.010) in the 70 mg volagidemab group. No increase in hypoglycemia was observed with volagidemab therapy; however, increases in serum transaminases, low-density lipoprotein (LDL)-cholesterol and blood pressure were observed. Although the primary endpoint did not meet the prespecified significance level, we believe that the observed reduction in HbA1c and tolerable safety profile provide a rationale for further randomized studies to define the long-term efficacy and safety of volagidemab in patients with T1D.
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Affiliation(s)
- Jeremy Pettus
- Division of Endocrinology, University of California San Diego, La Jolla, CA, USA.
| | - Schafer C Boeder
- Division of Endocrinology, University of California San Diego, La Jolla, CA, USA
| | | | | | | | - Halis K Akturk
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Campus, Aurora, CO, USA
| | | | | | | | | | | | - Ren Xu
- REMD Biotherapeutics, Camarillo, CA, USA
| | - Hai Yan
- REMD Biotherapeutics, Camarillo, CA, USA
| | - Dung Thai
- REMD Biotherapeutics, Camarillo, CA, USA
| | - Satish K Garg
- Barbara Davis Center for Diabetes, University of Colorado Anschutz Campus, Aurora, CO, USA
| | - Samuel Klein
- Center for Human Nutrition, Washington University School of Medicine, St. Louis, MO and Sansum Diabetes Research Institute, Santa Barbara, CA, USA
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7
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Habegger KM. Cross Talk Between Insulin and Glucagon Receptor Signaling in the Hepatocyte. Diabetes 2022; 71:1842-1851. [PMID: 35657690 PMCID: PMC9450567 DOI: 10.2337/dbi22-0002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Accepted: 05/19/2022] [Indexed: 11/13/2022]
Abstract
While the consumption of external energy (i.e., feeding) is essential to life, this action induces a temporary disturbance of homeostasis in an animal. A primary example of this effect is found in the regulation of glycemia. In the fasted state, stored energy is released to maintain physiological glycemic levels. Liver glycogen is liberated to glucose, glycerol and (glucogenic) amino acids are used to build new glucose molecules (i.e., gluconeogenesis), and fatty acids are oxidized to fuel long-term energetic demands. This regulation is driven primarily by the counterregulatory hormones epinephrine, growth hormone, cortisol, and glucagon. Conversely, feeding induces a rapid influx of diverse nutrients, including glucose, that disrupt homeostasis. Consistently, a host of hormonal and neural systems under the coordination of insulin are engaged in the transition from fasting to prandial states to reduce this disruption. The ultimate action of these systems is to appropriately store the newly acquired energy and to return to the homeostatic norm. Thus, at first glance it is tempting to assume that glucagon is solely antagonistic regarding the anabolic effects of insulin. We have been intrigued by the role of glucagon in the prandial transition and have attempted to delineate its role as beneficial or inhibitory to glycemic control. The following review highlights this long-known yet poorly understood hormone.
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Affiliation(s)
- Kirk M. Habegger
- Comprehensive Diabetes Center and Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Alabama at Birmingham, Birmingham, AL
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8
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Glucagon-receptor-antagonism-mediated β-cell regeneration as an effective anti-diabetic therapy. Cell Rep 2022; 39:110872. [PMID: 35649369 DOI: 10.1016/j.celrep.2022.110872] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Revised: 02/12/2022] [Accepted: 05/04/2022] [Indexed: 01/10/2023] Open
Abstract
Type 1 diabetes mellitus (T1D) is a chronic disease with potentially severe complications, and β-cell deficiency underlies this disease. Despite active research, no therapy to date has been able to induce β-cell regeneration in humans. Here, we discover the β-cell regenerative effects of glucagon receptor antibody (anti-GcgR). Treatment with anti-GcgR in mouse models of β-cell deficiency leads to reversal of hyperglycemia, increase in plasma insulin levels, and restoration of β-cell mass. We demonstrate that both β-cell proliferation and α- to β-cell transdifferentiation contribute to anti-GcgR-induced β-cell regeneration. Interestingly, anti-GcgR-induced α-cell hyperplasia can be uncoupled from β-cell regeneration after antibody clearance from the body. Importantly, we are able to show that anti-GcgR-induced β-cell regeneration is also observed in non-human primates. Furthermore, anti-GcgR and anti-CD3 combination therapy reverses diabetes and increases β-cell mass in a mouse model of autoimmune diabetes.
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9
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Qiao L, Saget S, Lu C, Zang T, Dzyuba B, Hay WW, Shao J. The Essential Role of Pancreatic α-Cells in Maternal Metabolic Adaptation to Pregnancy. Diabetes 2022; 71:978-988. [PMID: 35147704 PMCID: PMC9044124 DOI: 10.2337/db21-0923] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2021] [Accepted: 02/07/2022] [Indexed: 11/13/2022]
Abstract
Pancreatic α-cells are important in maintaining metabolic homeostasis, but their role in regulating maternal metabolic adaptations to pregnancy has not been studied. The objective of this study was to determine whether pancreatic α-cells respond to pregnancy and their contribution to maternal metabolic adaptation. With use of C57BL/6 mice, the findings of our study showed that pregnancy induced a significant increase of α-cell mass by promoting α-cell proliferation that was associated with a transitory increase of maternal serum glucagon concentration in early pregnancy. Maternal pancreatic GLP-1 content also was significantly increased during pregnancy. Using the inducible Cre/loxp technique, we ablated the α-cells (α-null) before and during pregnancy while maintaining enteroendocrine L-cells and serum GLP-1 in the normal range. In contrast to an improved glucose tolerance test (GTT) before pregnancy, significantly impaired GTT and remarkably higher serum glucose concentrations in the fed state were observed in α-null dams. Glucagon receptor antagonism treatment, however, did not affect measures of maternal glucose metabolism, indicating a dispensable role of glucagon receptor signaling in maternal glucose homeostasis. However, the GLP-1 receptor agonist improved insulin production and glucose metabolism of α-null dams. Furthermore, GLP-1 receptor antagonist Exendin (9-39) attenuated pregnancy-enhanced insulin secretion and GLP-1 restored glucose-induced insulin secretion of cultured islets from α-null dams. Together, these results demonstrate that α-cells play an essential role in controlling maternal metabolic adaptation to pregnancy by enhancing insulin secretion.
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Affiliation(s)
- Liping Qiao
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
| | - Sarah Saget
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
| | - Cindy Lu
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
| | - Tianyi Zang
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
| | - Brianna Dzyuba
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
| | | | - Jianhua Shao
- Department of Pediatrics, University of California, San Diego, La Jolla, CA
- Corresponding author: Jianhua Shao,
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10
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Holter MM, Saikia M, Cummings BP. Alpha-cell paracrine signaling in the regulation of beta-cell insulin secretion. Front Endocrinol (Lausanne) 2022; 13:934775. [PMID: 35957816 PMCID: PMC9360487 DOI: 10.3389/fendo.2022.934775] [Citation(s) in RCA: 17] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/03/2022] [Accepted: 06/28/2022] [Indexed: 01/14/2023] Open
Abstract
As an incretin hormone, glucagon-like peptide 1 (GLP-1) lowers blood glucose levels by enhancing glucose-stimulated insulin secretion from pancreatic beta-cells. Therapies targeting the GLP-1 receptor (GLP-1R) use the classical incretin model as a physiological framework in which GLP-1 secreted from enteroendocrine L-cells acts on the beta-cell GLP-1R. However, this model has come into question, as evidence demonstrating local, intra-islet GLP-1 production has advanced the competing hypothesis that the incretin activity of GLP-1 may reflect paracrine signaling of GLP-1 from alpha-cells on GLP-1Rs on beta-cells. Additionally, recent studies suggest that alpha-cell-derived glucagon can serve as an additional, albeit less potent, ligand for the beta-cell GLP-1R, thereby expanding the role of alpha-cells beyond that of a counterregulatory cell type. Efforts to understand the role of the alpha-cell in the regulation of islet function have revealed both transcriptional and functional heterogeneity within the alpha-cell population. Further analysis of this heterogeneity suggests that functionally distinct alpha-cell subpopulations display alterations in islet hormone profile. Thus, the role of the alpha-cell in glucose homeostasis has evolved in recent years, such that alpha-cell to beta-cell communication now presents a critical axis regulating the functional capacity of beta-cells. Herein, we describe and integrate recent advances in our understanding of the impact of alpha-cell paracrine signaling on insulin secretory dynamics and how this intra-islet crosstalk more broadly contributes to whole-body glucose regulation in health and under metabolic stress. Moreover, we explore how these conceptual changes in our understanding of intra-islet GLP-1 biology may impact our understanding of the mechanisms of incretin-based therapeutics.
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Affiliation(s)
- Marlena M. Holter
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
- *Correspondence: Marlena M. Holter,
| | - Mridusmita Saikia
- Department of Biomedical Sciences, College of Veterinary Medicine, Cornell University, Ithaca, NY, United States
- Nancy E. and Peter C. Meinig School of Biomedical Engineering, Cornell University, Ithaca, NY, United States
| | - Bethany P. Cummings
- School of Medicine, Department of Surgery, Center for Alimentary and Metabolic Sciences, University of California, Davis, Sacramento, CA, United States
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11
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Glucagon blockade restores functional β-cell mass in type 1 diabetic mice and enhances function of human islets. Proc Natl Acad Sci U S A 2021; 118:2022142118. [PMID: 33619103 PMCID: PMC7936318 DOI: 10.1073/pnas.2022142118] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/08/2023] Open
Abstract
Both type 1 and type 2 diabetes are associated with reduced β-cell mass or function, resulting from decreased proliferation and increased apoptosis. Understanding the signals governing β-cell survival and regeneration is critical for developing strategies to maintain healthy populations of these cells in individuals. Both forms of diabetes are associated with hyperglucagonemia and an increased plasma glucagon:insulin ratio. Glucagon excess contributes to metabolic dysregulation of the diabetic state and glucagon receptor antagonism is a potential target area for the treatment and prevention of diabetes. Our studies presented here suggest that blockade of glucagon signaling lowers glycemia in mouse models of type 1 diabetes while enhancing formation of functional β-cell mass and production of insulin-positive cells from α-cell precursors. We evaluated the potential for a monoclonal antibody antagonist of the glucagon receptor (Ab-4) to maintain glucose homeostasis in type 1 diabetic rodents. We noted durable and sustained improvements in glycemia which persist long after treatment withdrawal. Ab-4 promoted β-cell survival and enhanced the recovery of insulin+ islet mass with concomitant increases in circulating insulin and C peptide. In PANIC-ATTAC mice, an inducible model of β-cell apoptosis which allows for robust assessment of β-cell regeneration following caspase-8–induced diabetes, Ab-4 drove a 6.7-fold increase in β-cell mass. Lineage tracing suggests that this restoration of functional insulin-producing cells was at least partially driven by α-cell-to-β-cell conversion. Following hyperglycemic onset in nonobese diabetic (NOD) mice, Ab-4 treatment promoted improvements in C-peptide levels and insulin+ islet mass was dramatically increased. Lastly, diabetic mice receiving human islet xenografts showed stable improvements in glycemic control and increased human insulin secretion.
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12
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Zeigerer A, Sekar R, Kleinert M, Nason S, Habegger KM, Müller TD. Glucagon's Metabolic Action in Health and Disease. Compr Physiol 2021; 11:1759-1783. [PMID: 33792899 PMCID: PMC8513137 DOI: 10.1002/cphy.c200013] [Citation(s) in RCA: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022]
Abstract
Discovered almost simultaneously with insulin, glucagon is a pleiotropic hormone with metabolic action that goes far beyond its classical role to increase blood glucose. Albeit best known for its ability to directly act on the liver to increase de novo glucose production and to inhibit glycogen breakdown, glucagon lowers body weight by decreasing food intake and by increasing metabolic rate. Glucagon further promotes lipolysis and lipid oxidation and has positive chronotropic and inotropic effects in the heart. Interestingly, recent decades have witnessed a remarkable renaissance of glucagon's biology with the acknowledgment that glucagon has pharmacological value beyond its classical use as rescue medication to treat severe hypoglycemia. In this article, we summarize the multifaceted nature of glucagon with a special focus on its hepatic action and discuss the pharmacological potential of either agonizing or antagonizing the glucagon receptor for health and disease. © 2021 American Physiological Society. Compr Physiol 11:1759-1783, 2021.
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Affiliation(s)
- Anja Zeigerer
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Revathi Sekar
- Institute for Diabetes and Cancer, Helmholtz Center Munich, Neuherberg, Germany
- German Center for Diabetes Research (DZD), Neuherberg, Germany
| | - Maximilian Kleinert
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Institute for Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany
- Section of Molecular Physiology, Department of Nutrition, Exercise and Sports, Faculty of Science, University of Copenhagen, Copenhagen, Denmark
| | - Shelly Nason
- Comprehensive Diabetes Center, Department of Medicine - Endocrinology, Diabetes & Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Kirk M. Habegger
- Comprehensive Diabetes Center, Department of Medicine - Endocrinology, Diabetes & Metabolism, University of Alabama at Birmingham, Birmingham, Alabama, USA
| | - Timo D. Müller
- German Center for Diabetes Research (DZD), Neuherberg, Germany
- Institute for Diabetes and Obesity, Helmholtz Center Munich, Neuherberg, Germany
- Department of Pharmacology, Experimental Therapy and Toxicology, Institute of Experimental and Clinical Pharmacology and Pharmacogenomics, Eberhard Karls University Hospitals and Clinics, Tübingen, Germany
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13
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Wang J, Osada T, Morse MA, Calzone F, Yan H, Thai D, Lyerly HK. Targeting the glucagon receptor signaling pathway as a novel strategy to counteract PI3K inhibitor induced hyperglycemia while sustaining tumor PI3K inhibition. Leuk Lymphoma 2021; 62:1761-1764. [PMID: 33576297 DOI: 10.1080/10428194.2021.1881504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Affiliation(s)
- Jie Wang
- Department of Medicine, Duke Cancer Institute, Durham, NC, USA
| | - Takuya Osada
- Department of Surgery, Duke Cancer Institute, Durham, NC, USA
| | - Michael A Morse
- Department of Medicine, Duke Cancer Institute, Durham, NC, USA
| | | | - Hai Yan
- REMD Biotherapeutics, Camarillo, CA, USA
| | - Dung Thai
- REMD Biotherapeutics, Camarillo, CA, USA
| | - H Kim Lyerly
- Department of Surgery, Duke Cancer Institute, Durham, NC, USA
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14
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Hunt JE, Yassin M, Olsen J, Hartmann B, Holst JJ, Kissow H. Intestinal Growth in Glucagon Receptor Knockout Mice Is Not Associated With the Formation of AOM/DSS-Induced Tumors. Front Endocrinol (Lausanne) 2021; 12:695145. [PMID: 34108943 PMCID: PMC8181411 DOI: 10.3389/fendo.2021.695145] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/14/2021] [Accepted: 05/03/2021] [Indexed: 12/22/2022] Open
Abstract
Treatment with exogenous GLP-2 has been shown to accelerate the growth of intestinal adenomas and adenocarcinomas in experimental models of colonic neoplasia, however, the role of endogenous GLP-2 in tumor promotion is less well known. Mice with a global deletion of the glucagon receptor (Gcgr-/-) display an increase in circulating GLP-1 and GLP-2. Due to the intestinotrophic nature of GLP-2, we hypothesized that Gcgr-/- mice would be more susceptible to colonic dysplasia in a model of inflammation-induced colonic carcinogenesis. Female Gcgr-/- mice were first characterized for GLP-2 secretion and in a subsequent study they were given a single injection with the carcinogen azoxymethane (7.5 mg/kg) and treated with dextran sodium sulfate (DSS) (3%) for six days (n=19 and 9). A cohort of animals (n=4) received a colonoscopy 12 days following DSS treatment and all animals were sacrificed after six weeks. Disruption of glucagon receptor signaling led to increased GLP-2 secretion (p<0.0001) and an increased concentration of GLP-2 in the pancreas of Gcgr-/- mice, coinciding with an increase in small intestinal (p<0.0001) and colonic (p<0.05) weight. Increased villus height was recorded in the duodenum (p<0.001) and crypt depth was increased in the duodenum and jejunum (p<0.05 and p<0.05). Disruption of glucagon receptor signaling did not affect body weight during AOM/DSS treatment, neither did it affect the inflammatory score assessed during colonoscopy or the number of large and small adenomas present at the end of the study period. In conclusion, despite the increased endogenous GLP-2 secretion Gcgr-/- mice were not more susceptible to AOM/DSS-induced tumors.
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Affiliation(s)
- Jenna Elizabeth Hunt
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Mohammad Yassin
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jørgen Olsen
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Bolette Hartmann
- Department of Biomedical Sciences and Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Jens Juul Holst
- Department of Biomedical Sciences and Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Hannelouise Kissow
- Department of Biomedical Sciences and Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- *Correspondence: Hannelouise Kissow,
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15
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Lang S, Wei R, Wei T, Gu L, Feng J, Yan H, Yang J, Hong T. Glucagon receptor antagonism promotes the production of gut proglucagon-derived peptides in diabetic mice. Peptides 2020; 131:170349. [PMID: 32561493 DOI: 10.1016/j.peptides.2020.170349] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2020] [Revised: 06/14/2020] [Accepted: 06/15/2020] [Indexed: 12/23/2022]
Abstract
Glucagon is an essential regulator of glucose homeostasis, particularly in type 2 diabetes (T2D). Blocking the glucagon receptor (GCGR) in diabetic animals and humans has been shown to alleviate hyperglycemia and increase circulating glucagon-like peptide-1 (GLP-1) levels. However, the origin of the upregulated GLP-1 remains to be clarified. Here, we administered high-fat diet + streptozotocin-induced T2D mice and diabetic db/db mice with REMD 2.59, a fully competitive antagonistic human GCGR monoclonal antibody (mAb) for 12 weeks. GCGR mAb treatment decreased fasting blood glucose levels and increased plasma GLP-1 levels in the T2D mice. In addition, GCGR mAb upregulated preproglucagon gene expression and the contents of gut proglucagon-derived peptides, particularly GLP-1, in the small intestine and colon. Notably, T2D mice treated with GCGR mAb displayed a higher L-cell density in the small intestine and colon, which was associated with increased numbers of LK-cells coexpressing GLP-1 and glucose-dependent insulinotropic polypeptide and reduced L-cell apoptosis. Furthermore, GCGR mAb treatment upregulated GLP-1 production in the pancreas, which was detected at lower levels than in the intestine. Collectively, these results suggest that GCGR mAb can increase intestinal GLP-1 production and L-cell number by enhancing LK-cell expansion and inhibiting L-cell apoptosis in T2D.
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MESH Headings
- Animals
- Antibodies, Monoclonal/pharmacology
- Antibodies, Neutralizing/pharmacology
- Apoptosis/genetics
- Blood Glucose/metabolism
- Colon/drug effects
- Colon/metabolism
- Diabetes Mellitus, Experimental/drug therapy
- Diabetes Mellitus, Experimental/etiology
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Diet, High-Fat/adverse effects
- Fasting/metabolism
- Gastric Inhibitory Polypeptide/genetics
- Gastric Inhibitory Polypeptide/metabolism
- Gene Expression Regulation
- Glucagon-Like Peptide 1/genetics
- Glucagon-Like Peptide 1/metabolism
- Humans
- Intestine, Small/drug effects
- Intestine, Small/metabolism
- Male
- Mice
- Mice, Inbred C57BL
- Pancreas/drug effects
- Pancreas/metabolism
- Proglucagon/genetics
- Proglucagon/metabolism
- Receptors, Glucagon/antagonists & inhibitors
- Receptors, Glucagon/genetics
- Receptors, Glucagon/metabolism
- Signal Transduction
- Streptozocin/administration & dosage
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Affiliation(s)
- Shan Lang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China; Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing 100191, China
| | - Rui Wei
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China; Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing 100191, China
| | - Tianjiao Wei
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China; Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing 100191, China
| | - Liangbiao Gu
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
| | - Jin Feng
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China
| | - Hai Yan
- REMD Biotherapeutics, Camarillo, CA 93012, USA; Beijing Cosci-REMD, Beijing 102206, China
| | - Jin Yang
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China.
| | - Tianpei Hong
- Department of Endocrinology and Metabolism, Peking University Third Hospital, Beijing 100191, China; Clinical Stem Cell Research Center, Peking University Third Hospital, Beijing 100191, China.
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16
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Viloria K, Nasteska D, Briant LJB, Heising S, Larner DP, Fine NHF, Ashford FB, da Silva Xavier G, Ramos MJ, Hasib A, Cuozzo F, Manning Fox JE, MacDonald PE, Akerman I, Lavery GG, Flaxman C, Morgan NG, Richardson SJ, Hewison M, Hodson DJ. Vitamin-D-Binding Protein Contributes to the Maintenance of α Cell Function and Glucagon Secretion. Cell Rep 2020; 31:107761. [PMID: 32553153 PMCID: PMC7302426 DOI: 10.1016/j.celrep.2020.107761] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 04/22/2020] [Accepted: 05/21/2020] [Indexed: 02/06/2023] Open
Abstract
Vitamin-D-binding protein (DBP) or group-specific component of serum (GC-globulin) carries vitamin D metabolites from the circulation to target tissues. DBP is highly localized to the liver and pancreatic α cells. Although DBP serum levels, gene polymorphisms, and autoantigens have all been associated with diabetes risk, the underlying mechanisms remain unknown. Here, we show that DBP regulates α cell morphology, α cell function, and glucagon secretion. Deletion of DBP leads to smaller and hyperplastic α cells, altered Na+ channel conductance, impaired α cell activation by low glucose, and reduced rates of glucagon secretion both in vivo and in vitro. Mechanistically, this involves reversible changes in islet microfilament abundance and density, as well as changes in glucagon granule distribution. Defects are also seen in β cell and δ cell function. Immunostaining of human pancreata reveals generalized loss of DBP expression as a feature of late-onset and long-standing, but not early-onset, type 1 diabetes. Thus, DBP regulates α cell phenotype, with implications for diabetes pathogenesis.
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Affiliation(s)
- Katrina Viloria
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Daniela Nasteska
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Linford J B Briant
- Oxford Centre for Diabetes, Endocrinology and Metabolism, Radcliffe Department of Medicine, University of Oxford, Oxford OX3 7LE, UK
| | - Silke Heising
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK
| | - Dean P Larner
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK
| | - Nicholas H F Fine
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Fiona B Ashford
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Gabriela da Silva Xavier
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK
| | - Maria Jiménez Ramos
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK
| | - Annie Hasib
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Federica Cuozzo
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK
| | - Jocelyn E Manning Fox
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - Patrick E MacDonald
- Department of Pharmacology and Alberta Diabetes Institute, University of Alberta, Edmonton, AB T6G 2E1, Canada
| | - Ildem Akerman
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK
| | - Gareth G Lavery
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK
| | - Christine Flaxman
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Noel G Morgan
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Sarah J Richardson
- Institute of Biomedical and Clinical Science, University of Exeter Medical School, Exeter EX2 5DW, UK
| | - Martin Hewison
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK.
| | - David J Hodson
- Institute of Metabolism and Systems Research (IMSR), University of Birmingham, Birmingham B15 2TT, UK; Centre for Endocrinology, Diabetes and Metabolism, Birmingham Health Partners, Birmingham B15 2TT, UK; Centre of Membrane Proteins and Receptors (COMPARE), University of Birmingham and University of Nottingham, Midlands, UK.
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17
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Abstract
Glucagon and its partner insulin are dually linked in both their secretion from islet cells and their action in the liver. Glucagon signaling increases hepatic glucose output, and hyperglucagonemia is partly responsible for the hyperglycemia in diabetes, making glucagon an attractive target for therapeutic intervention. Interrupting glucagon signaling lowers blood glucose but also results in hyperglucagonemia and α-cell hyperplasia. Investigation of the mechanism for α-cell proliferation led to the description of a conserved liver-α-cell axis where glucagon is a critical regulator of amino acid homeostasis. In return, amino acids regulate α-cell function and proliferation. New evidence suggests that dysfunction of the axis in humans may result in the hyperglucagonemia observed in diabetes. This discussion outlines important but often overlooked roles for glucagon that extend beyond glycemia and supports a new role for α-cells as amino acid sensors.
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Affiliation(s)
- E Danielle Dean
- Division of Diabetes, Endocrinology, and Metabolism, Department of Medicine, Vanderbilt University Medical Center, and Department of Molecular Physiology and Biophysics, Vanderbilt University School of Medicine, Nashville, TN
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18
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Finan B, Capozzi ME, Campbell JE. Repositioning Glucagon Action in the Physiology and Pharmacology of Diabetes. Diabetes 2020; 69:532-541. [PMID: 31178432 PMCID: PMC7085250 DOI: 10.2337/dbi19-0004] [Citation(s) in RCA: 64] [Impact Index Per Article: 16.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/18/2019] [Accepted: 05/30/2019] [Indexed: 01/03/2023]
Abstract
Glucagon is historically described as the counterregulatory hormone to insulin, induced by fasting/hypoglycemia to raise blood glucose through action mediated in the liver. However, it is becoming clear that the biology of glucagon is much more complex and extends beyond hepatic actions to exert control on glucose metabolism. We discuss the inconsistencies with the canonical view that glucagon is primarily a hyperglycemic agent driven by fasting/hypoglycemia and highlight the recent advances that have reshaped the metabolic role of glucagon. These concepts are placed within the context of both normal physiology and the pathophysiology of disease and then extended to discuss emerging strategies that incorporate glucagon agonism in the pharmacology of treating diabetes.
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Affiliation(s)
- Brian Finan
- Novo Nordisk Research Center, Indianapolis, IN
| | - Megan E Capozzi
- Duke Molecular Physiology Institute, Duke University, Durham, NC
| | - Jonathan E Campbell
- Duke Molecular Physiology Institute, Duke University, Durham, NC
- Division of Endocrinology, Department of Medicine, Duke University, Durham, NC
- Department of Pharmacology and Cancer Biology, Duke University, Durham, NC
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19
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Pettus JH, D'Alessio D, Frias JP, Vajda EG, Pipkin JD, Rosenstock J, Williamson G, Zangmeister MA, Zhi L, Marschke KB. Efficacy and Safety of the Glucagon Receptor Antagonist RVT-1502 in Type 2 Diabetes Uncontrolled on Metformin Monotherapy: A 12-Week Dose-Ranging Study. Diabetes Care 2020; 43:161-168. [PMID: 31694861 DOI: 10.2337/dc19-1328] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/05/2019] [Accepted: 10/15/2019] [Indexed: 02/03/2023]
Abstract
OBJECTIVE Evaluate the safety and efficacy of RVT-1502, a novel oral glucagon receptor antagonist, in subjects with type 2 diabetes inadequately controlled on metformin. RESEARCH DESIGN AND METHODS In a phase 2, double-blind, randomized, placebo-controlled study, subjects with type 2 diabetes (n = 166) on a stable dose of metformin were randomized (1:1:1:1) to placebo or RVT-1502 5, 10, or 15 mg once daily for 12 weeks. The primary end point was change from baseline in HbA1c for each dose of RVT-1502 compared with placebo. Secondary end points included change from baseline in fasting plasma glucose (FPG) and safety assessments. RESULTS Over 12 weeks, RVT-1502 significantly reduced HbA1c relative to placebo by 0.74%, 0.76%, and 1.05% in the 5-, 10-, and 15-mg groups (P < 0.001), respectively, and FPG decreased by 2.1, 2.2, and 2.6 mmol/L (P < 0.001). The proportions of subjects achieving an HbA1c <7.0% were 19.5%, 39.5%, 39.5%, and 45.0% with placebo and RVT-1502 5, 10, and 15 mg (P ≤ 0.02 vs. placebo). The frequency of hypoglycemia was low, and no episodes were severe. Mild increases in mean aminotransferase levels remaining below the upper limit of normal were observed with RVT-1502 but were reversible and did not appear to be dose related, with no other liver parameter changes. Weight and lipid changes were similar between RVT-1502 and placebo. RVT-1502-associated mild increases in blood pressure were not dose related or consistent across time. CONCLUSIONS Glucagon receptor antagonism with RVT-1502 significantly lowers HbA1c and FPG, with a safety profile that supports further clinical development with longer-duration studies (NCT02851849).
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Affiliation(s)
| | | | | | - Eric G Vajda
- Ligand Pharmaceuticals Incorporated, San Diego, CA
| | | | | | | | | | - Lin Zhi
- Ligand Pharmaceuticals Incorporated, San Diego, CA
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20
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Himuro M, Miyatsuka T, Suzuki L, Miura M, Katahira T, Goto H, Nishida Y, Sasaki S, Koike M, Shiota C, Gittes GK, Fujitani Y, Watada H. Cellular Autophagy in α Cells Plays a Role in the Maintenance of Islet Architecture. J Endocr Soc 2019; 3:1979-1992. [PMID: 31620668 PMCID: PMC6786006 DOI: 10.1210/js.2019-00075] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/22/2019] [Accepted: 07/22/2019] [Indexed: 01/31/2023] Open
Abstract
Autophagy is known to play a pivotal role in intracellular quality control through the degradation of subcellular damaged organelles and components. Whereas autophagy is essential for maintaining β-cell function in pancreatic islets, it remains unclear as to how the cellular autophagy affects the homeostasis and function of glucagon-secreting α cells. To investigate the role of autophagy in α cells, we generated a mutant mouse model lacking Atg7, a key molecule for autophagosome formation, specifically in α cells. Histological analysis demonstrated more glucagon-positive cells, with a multilayered structure, in the islets under Atg7 deficiency, although metabolic profiles, such as body weight, blood glucose, and plasma glucagon levels were comparable between Atg7-deficient mice and control littermates. Consistent with our previous findings that Atg7 deficiency suppressed β-cell proliferation, cellular proliferation was suppressed in Atg7-deficient α cells. These findings suggest that α-cell autophagy plays a role in maintaining α-cell area and normal islet architecture but appears to be dispensable for metabolic homeostasis.
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Affiliation(s)
- Miwa Himuro
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Takeshi Miyatsuka
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Center for Identification of Diabetic Therapeutic Targets, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Luka Suzuki
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Center for Identification of Diabetic Therapeutic Targets, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Masaki Miura
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Takehiro Katahira
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Hiromasa Goto
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Yuya Nishida
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Shugo Sasaki
- Department of Surgery, The University of British Columbia, Vancouver BC, Canada
| | - Masato Koike
- Departments of Cell Biology and Neurosciences, Juntendo University Graduate School of Medicine, Tokyo, Japan
| | - Chiyo Shiota
- Division of Pediatric Surgery, Department of Surgery, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - George K Gittes
- Division of Pediatric Surgery, Department of Surgery, Children's Hospital of Pittsburgh of UPMC, University of Pittsburgh School of Medicine, Pittsburgh, Pennsylvania
| | - Yoshio Fujitani
- Laboratory of Developmental Biology & Metabolism, Institute for Molecular & Cellular Regulation, Gunma University, Maebashi, Japan
| | - Hirotaka Watada
- Department of Metabolism and Endocrinology, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Center for Identification of Diabetic Therapeutic Targets, Juntendo University Graduate School of Medicine, Tokyo, Japan.,Center for Therapeutic Innovations in Diabetes, Juntendo University Graduate School of Medicine, Tokyo, Japan
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21
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Sharma AX, Quittner-Strom EB, Lee Y, Johnson JA, Martin SA, Yu X, Li J, Lu J, Cai Z, Chen S, Wang MY, Zhang Y, Pearson MJ, Dorn AC, McDonald JG, Gordillo R, Yan H, Thai D, Wang ZV, Unger RH, Holland WL. Glucagon Receptor Antagonism Improves Glucose Metabolism and Cardiac Function by Promoting AMP-Mediated Protein Kinase in Diabetic Mice. Cell Rep 2019; 22:1760-1773. [PMID: 29444429 PMCID: PMC5978750 DOI: 10.1016/j.celrep.2018.01.065] [Citation(s) in RCA: 45] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2017] [Revised: 11/30/2017] [Accepted: 01/22/2018] [Indexed: 12/13/2022] Open
Abstract
The antidiabetic potential of glucagon receptor antagonism presents an opportunity for use in an insulin-centric clinical environment. To investigate the metabolic effects of glucagon receptor antagonism in type 2 diabetes, we treated Leprdb/db and Lepob/ob mice with REMD 2.59, a human monoclonal antibody and competitive antagonist of the glucagon receptor. As expected, REMD 2.59 suppresses hepatic glucose production and improves glycemia. Surprisingly, it also enhances insulin action in both liver and skeletal muscle, coinciding with an increase in AMP-activated protein kinase (AMPK)-mediated lipid oxidation. Furthermore, weekly REMD 2.59 treatment over a period of months protects against diabetic cardiomyopathy. These functional improvements are not derived simply from correcting the systemic milieu; nondiabetic mice with cardiac-specific overexpression of lipoprotein lipase also show improvements in contractile function after REMD 2.59 treatment. These observations suggest that hyperglucagonemia enables lipotoxic conditions, allowing the development of insulin resistance and cardiac dysfunction during disease progression.
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Affiliation(s)
- Ankit X Sharma
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Ezekiel B Quittner-Strom
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Young Lee
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA; Medical Service, Veteran's Administration North Texas Health Care System, Dallas, TX 75216, USA
| | - Joshua A Johnson
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Sarah A Martin
- Department of Molecular Genetics, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Xinxin Yu
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA; Medical Service, Veteran's Administration North Texas Health Care System, Dallas, TX 75216, USA
| | - Jianping Li
- Division of Cardiology, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - John Lu
- REMD Biotherapeutics Inc., Camarillo, CA 93012, USA
| | | | - Shiuhwei Chen
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - May-Yun Wang
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA; Medical Service, Veteran's Administration North Texas Health Care System, Dallas, TX 75216, USA
| | - Yiyi Zhang
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Mackenzie J Pearson
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Andie C Dorn
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Jeffrey G McDonald
- Department of Molecular Genetics, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA; Center for Human Nutrition, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Ruth Gordillo
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Hai Yan
- REMD Biotherapeutics Inc., Camarillo, CA 93012, USA
| | - Dung Thai
- REMD Biotherapeutics Inc., Camarillo, CA 93012, USA
| | - Zhao V Wang
- Division of Cardiology, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA
| | - Roger H Unger
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA; Medical Service, Veteran's Administration North Texas Health Care System, Dallas, TX 75216, USA
| | - William L Holland
- Touchstone Diabetes Center, Department of Internal Medicine, The University of Texas Southwestern Medical Center, Dallas, TX 75390-8549, USA.
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22
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Galsgaard KD, Winther-Sørensen M, Pedersen J, Kjeldsen SAS, Rosenkilde MM, Wewer Albrechtsen NJ, Holst JJ. Glucose and amino acid metabolism in mice depend mutually on glucagon and insulin receptor signaling. Am J Physiol Endocrinol Metab 2019; 316:E660-E673. [PMID: 30807215 DOI: 10.1152/ajpendo.00410.2018] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Glucagon and insulin are important regulators of blood glucose. The importance of insulin receptor signaling for alpha-cell secretion and of glucagon receptor signaling for beta-cell secretion is widely discussed and of clinical interest. Amino acids are powerful secretagogues for both hormones, and glucagon controls amino acid metabolism through ureagenesis. The role of insulin in amino acid metabolism is less clear. Female C57BL/6JRj mice received an insulin receptor antagonist (IRA) (S961; 30 nmol/kg), a glucagon receptor antagonist (GRA) (25-2648; 100 mg/kg), or both GRA and IRA (GRA + IRA) 3 h before intravenous administration of similar volumes of saline, glucose (0.5 g/kg), or amino acids (1 µmol/g) while anesthetized with isoflurane. IRA caused basal hyperglycemia, hyperinsulinemia, and hyperglucagonemia. Unexpectedly, IRA lowered basal plasma concentrations of amino acids, whereas GRA increased amino acids, lowered glycemia, and increased glucagon but did not influence insulin concentrations. After administration of GRA + IRA, insulin secretion was significantly reduced compared with IRA administration alone. Blood glucose responses to a glucose and amino acid challenge were similar after vehicle and GRA + IRA administration but greater after IRA and lower after GRA. Anesthesia may have influenced the results, which otherwise strongly suggest that both hormones are essential for the maintenance of glucose homeostasis and that the secretion of both is regulated by powerful negative feedback mechanisms. In addition, insulin limits glucagon secretion, while endogenous glucagon stimulates insulin secretion, revealed during lack of insulin autocrine feedback. Finally, glucagon receptor signaling seems to be of greater importance for amino acid metabolism than insulin receptor signaling.
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Affiliation(s)
- Katrine D Galsgaard
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Marie Winther-Sørensen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Jens Pedersen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
- Department of Cardiology, Nephrology and Endocrinology, Nordsjaellands Hospital Hilleroed, University of Copenhagen, Hilleroed, Denmark
| | - Sasha A S Kjeldsen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Mette M Rosenkilde
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Nicolai J Wewer Albrechtsen
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
- Department of Clinical Biochemistry, Rigshospitalet, Copenhagen , Denmark
- Novo Nordisk Foundation Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
| | - Jens J Holst
- Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen , Copenhagen , Denmark
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23
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Gao C, Ren SV, Yu J, Baal U, Thai D, Lu J, Zeng C, Yan H, Wang Y. Glucagon Receptor Antagonism Ameliorates Progression of Heart Failure. JACC Basic Transl Sci 2019; 4:161-172. [PMID: 31061918 PMCID: PMC6488764 DOI: 10.1016/j.jacbts.2018.11.001] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/02/2018] [Revised: 11/01/2018] [Accepted: 11/02/2018] [Indexed: 02/08/2023]
Abstract
Mice were treated with a fully human monoclonal glucagon receptor antagonistic antibody REMD2.59 following myocardial infarction or pressure overload. REMD2.59 treatment blunted cardiac hypertrophy and fibrotic remodeling, and attenuated contractile dysfunction at 4 weeks after myocardial infarction. In addition, REMD2.59 treatment at the onset of pressure overload significantly suppressed cardiac hypertrophy and chamber dilation with marked preservation of cardiac systolic and diastolic function. Initiation of REMD2.59 treatment 2 weeks after pressure overload significantly blunted the progression of cardiac pathology. These results provide the first in vivo proof-of-concept evidence that glucagon receptor antagonism is a potentially efficacious therapy to ameliorate both onset and progression of heart failure.
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Affiliation(s)
- Chen Gao
- Department of Anesthesiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
- Address for correspondence: Dr. Yibin Wang or Dr. Chen Gao, Department of Anesthesiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, 650 Charles E. Young Drive, Room CHS 37-200J, Los Angeles, California 90095.
| | - Shuxun Vincent Ren
- Department of Anesthesiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Junyi Yu
- Department of Anesthesiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Ulysis Baal
- Department of Anesthesiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
| | - Dung Thai
- REMD Biotherapeutics, Camarillo, California
- Beijing Cosci-REMD Biotherapeutics, Beijing, China
| | - John Lu
- REMD Biotherapeutics, Camarillo, California
- Beijing Cosci-REMD Biotherapeutics, Beijing, China
| | - Chunyu Zeng
- Department of Cardiology, Daping Hospital, The Third Military Medical University, Chongqing, China
| | - Hai Yan
- REMD Biotherapeutics, Camarillo, California
- Beijing Cosci-REMD Biotherapeutics, Beijing, China
| | - Yibin Wang
- Department of Anesthesiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, Los Angeles, California
- Address for correspondence: Dr. Yibin Wang or Dr. Chen Gao, Department of Anesthesiology, Cardiovascular Research Laboratories, David Geffen School of Medicine, University of California, Los Angeles, 650 Charles E. Young Drive, Room CHS 37-200J, Los Angeles, California 90095.
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24
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De Groof TWM, Bobkov V, Heukers R, Smit MJ. Nanobodies: New avenues for imaging, stabilizing and modulating GPCRs. Mol Cell Endocrinol 2019; 484:15-24. [PMID: 30690070 DOI: 10.1016/j.mce.2019.01.021] [Citation(s) in RCA: 39] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/22/2019] [Accepted: 01/22/2019] [Indexed: 12/30/2022]
Abstract
The family of G protein-coupled receptors (GPCRs) is the largest class of membrane proteins and an important drug target due to their role in many (patho)physiological processes. Besides small molecules, GPCRs can be targeted by biologicals including antibodies and antibody fragments. This review describes the use of antibodies and in particular antibody fragments from camelid-derived heavy chain-only antibodies (nanobodies/VHHs/sdAbs) for detecting, stabilizing, modulating and therapeutically targeting GPCRs. Altogether, it becomes increasingly clear that the small size, structure and protruding antigen-binding loops of nanobodies are favorable features for the development of selective and potent GPCRs-binding molecules. This makes them attractive tools to modulate GPCR activity but also as targeting modalities for GPCR-directed therapeutics. In addition, these antibody-fragments are important tools in the stabilization of particular conformations of these receptors. Lastly, nanobodies, in contrast to conventional antibodies, can also easily be expressed intracellularly which render nanobodies important tools for studying GPCR function. Hence, GPCR-targeting nanobodies are ideal modalities to image, stabilize and modulate GPCR function.
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Affiliation(s)
- Timo W M De Groof
- Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands
| | - Vladimir Bobkov
- Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands; Argenx BVBA, Industriepark Zwijnaarde 7, 9052, Zwijnaarde, Belgium
| | - Raimond Heukers
- Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands; QVQ Holding B.V., Yalelaan 1, 3484 CL, Utrecht, the Netherlands
| | - Martine J Smit
- Amsterdam Institute for Molecules, Medicines and Systems (AIMMS), Division of Medicinal Chemistry, Faculty of Sciences, Vrije Universiteit, De Boelelaan 1108, 1081 HZ, Amsterdam, the Netherlands.
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25
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Abstract
Globally, 13% of the world's adult population is obese, and more than 400 million people suffer from diabetes. These conditions are both associated with significant morbidity, mortality and financial cost. Therefore, finding new pharmacological treatments is an imperative. Relative hyperglucagonaemia is seen in all types of diabetes, and has been implicated in its pathogenesis. Consequently, clinical trials are underway using drugs which block glucagon activity to treat type 2 diabetes. Conversely, exogenous glucagon can increase energy expenditure. Therefore, researchers are designing peptides that combine activation of the glucagon receptor with further incretin properties, which will treat obesity while mitigating the hyperglycaemic effects of glucagon. This review will discuss these conflicting physiological properties of glucagon, and the attempts to harness these effects pharmacologically.
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Affiliation(s)
- R V Scott
- Imperial College London, 6th Floor, Commonwealth Building, Hammersmith Hospital, London, W12 0NN, United Kingdom.
| | - S R Bloom
- Imperial College London, 6th Floor, Commonwealth Building, Hammersmith Hospital, London, W12 0NN, United Kingdom.
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26
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Thiessen SE, Derde S, Derese I, Dufour T, Vega CA, Langouche L, Goossens C, Peersman N, Vermeersch P, Vander Perre S, Holst JJ, Wouters PJ, Vanhorebeek I, Van den Berghe G. Role of Glucagon in Catabolism and Muscle Wasting of Critical Illness and Modulation by Nutrition. Am J Respir Crit Care Med 2017; 196:1131-1143. [PMID: 28475354 DOI: 10.1164/rccm.201702-0354oc] [Citation(s) in RCA: 37] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023] Open
Abstract
RATIONALE Critical illness is hallmarked by muscle wasting and disturbances in glucose, lipid, and amino acid homeostasis. Circulating concentrations of glucagon, a catabolic hormone that affects these metabolic pathways, are elevated during critical illness. Insight in the nutritional regulation of glucagon and its metabolic role during critical illness is lacking. OBJECTIVES To evaluate whether macronutrient infusion can suppress plasma glucagon during critical illness and study the role of illness-induced glucagon abundance in the disturbed glucose, lipid, and amino acid homeostasis and in muscle wasting during critical illness. METHODS In human and mouse studies, we infused macronutrients and manipulated glucagon availability up and down to investigate its acute and chronic metabolic role during critical illness. MEASUREMENTS AND MAIN RESULTS In critically ill patients, infusing glucose with insulin did not lower glucagon, whereas parenteral nutrition containing amino acids increased glucagon. In critically ill mice, infusion of amino acids increased glucagon and up-regulated markers of hepatic amino acid catabolism without affecting muscle wasting. Immunoneutralizing glucagon in critically ill mice only transiently affected glucose and lipid metabolism, did not affect muscle wasting, but drastically suppressed markers of hepatic amino acid catabolism and reversed the illness-induced hypoaminoacidemia. CONCLUSIONS These data suggest that elevated glucagon availability during critical illness increases hepatic amino acid catabolism, explaining the illness-induced hypoaminoacidemia, without affecting muscle wasting and without a sustained impact on blood glucose. Furthermore, amino acid infusion likely results in a further breakdown of amino acids in the liver, mediated by increased glucagon, without preventing muscle wasting. Clinical trial registered with www.clinicaltrials.gov (NCT 00512122).
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Affiliation(s)
- Steven E Thiessen
- 1 Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, and
| | - Sarah Derde
- 1 Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, and
| | - Inge Derese
- 1 Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, and
| | - Thomas Dufour
- 1 Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, and
| | - Chloé Albert Vega
- 1 Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, and
| | - Lies Langouche
- 1 Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, and
| | - Chloë Goossens
- 1 Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, and
| | - Nele Peersman
- 2 Department of Laboratory Medicine, KU Leuven, Leuven, Belgium; and
| | - Pieter Vermeersch
- 2 Department of Laboratory Medicine, KU Leuven, Leuven, Belgium; and
| | - Sarah Vander Perre
- 1 Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, and
| | - Jens J Holst
- 3 Novo Nordisk Foundation Center for Basic Metabolic Research and.,4 Department of Biomedical Sciences, Panum Institute, University of Copenhagen, Copenhagen, Denmark
| | - Pieter J Wouters
- 1 Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, and
| | - Ilse Vanhorebeek
- 1 Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, and
| | - Greet Van den Berghe
- 1 Clinical Division and Laboratory of Intensive Care Medicine, Department of Cellular and Molecular Medicine, and
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27
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Scheen AJ, Paquot N, Lefèbvre PJ. Investigational glucagon receptor antagonists in Phase I and II clinical trials for diabetes. Expert Opin Investig Drugs 2017; 26:1373-1389. [PMID: 29052441 DOI: 10.1080/13543784.2017.1395020] [Citation(s) in RCA: 58] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
INTRODUCTION Despite type 2 diabetes (T2D) being recognized as a bihormonal pancreatic disease, current therapies are mainly focusing on insulin, while targeting glucagon has been long dismissed. However, glucagon receptor (GCGr) antagonists are currently investigated in clinical trials. Area covered: Following a brief description of the rationale for antagonizing GCGr in T2D, lessons from GCGr knock-out mice and pharmacological means to antagonize GCGr, a detailed description of the main results obtained with GCGr antagonists in Phase I-II clinical trials is provided. The development of several small molecules has been discontinued, while new ones are currently considered as well as innovative approaches such as monoclonal antibodies or antisense oligonucleotides inhibiting GCGr gene expression. Their potential benefits but also limitations are discussed. Expert opinion: The proof-of-concept that antagonizing GCGr improves glucose control in T2D has been confirmed in humans. Nevertheless, some adverse events led to stopping the development of some of these GCGr antagonists. New approaches seem to have a better benefit/risk balance, although none has progressed to Phase III clinical trials so far. Pharmacotherapy of T2D is becoming a highly competitive field so that GCGr antagonists should provide clear advantages over numerous existing glucose-lowering medications before eventually reaching clinical practice.
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Affiliation(s)
- André J Scheen
- a Division of Clinical Pharmacology , Center for Interdisciplinary Research on Medicines (CIRM), University of Liège , Belgium.,b Division of Diabetes, Nutrition and Metabolic Disorders, Department of Medicine , CHU , Liège , Belgium
| | - Nicolas Paquot
- b Division of Diabetes, Nutrition and Metabolic Disorders, Department of Medicine , CHU , Liège , Belgium
| | - Pierre J Lefèbvre
- b Division of Diabetes, Nutrition and Metabolic Disorders, Department of Medicine , CHU , Liège , Belgium
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28
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Selection and characterization of DNA aptamer against glucagon receptor by cell-SELEX. Sci Rep 2017; 7:7179. [PMID: 28775305 PMCID: PMC5543139 DOI: 10.1038/s41598-017-05840-w] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2017] [Accepted: 06/05/2017] [Indexed: 12/20/2022] Open
Abstract
Excessive secretion of glucagon, a functional insulin antagonist, significantly contributes to hyperglycemia. Glucagon exerts its physiological functions through activation of the glucagon receptor (GCGR). Inhibition of GCGR activity represents a potential therapeutic approach for reducing excess glucose production in diabetes mellitus. Aptamers are short DNA or RNA oligonucleotides evolved from systematic evolution of ligands by exponential enrichment (SELEX). Here, we have successfully selected a DNA aptamer against GCGR by cell-SELEX, which can specifically bind membrane protein of CHO-GCGR cells with a Kd of 52.7 ± 5.1 nM. Aptamer-mediated pull-down and gcgr knockdown assay verified that GCGR was the target of aptamer GR-3. Binding analysis revealed that GR-3 could recognize other cells with different affinity according to the level of GCGR protein expressed in these cells. Hepatic tissue imaging suggested that GR-3 could bind the cell membrane of hepatic tissues. With the advantages of small size, high binding affinity, good stability, lack of immunogenicity, and easy synthesis, aptamer GR-3 against GCGR can be a promising tool with the potential to attenuate hyperglycemia in diabetes mellitus.
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29
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Mani BK, Uchida A, Lee Y, Osborne-Lawrence S, Charron MJ, Unger RH, Berglund ED, Zigman JM. Hypoglycemic Effect of Combined Ghrelin and Glucagon Receptor Blockade. Diabetes 2017; 66:1847-1857. [PMID: 28487437 PMCID: PMC5482080 DOI: 10.2337/db16-1303] [Citation(s) in RCA: 24] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2016] [Accepted: 04/19/2017] [Indexed: 12/18/2022]
Abstract
Glucagon receptor (GcgR) blockade has been proposed as an alternative to insulin monotherapy for treating type 1 diabetes since deletion or inhibition of GcgRs corrects hyperglycemia in models of diabetes. The factors regulating glycemia in a setting devoid of insulin and glucagon function remain unclear but may include the hormone ghrelin. Not only is ghrelin release controlled by glucose but also ghrelin has many actions that can raise or reduce falls in blood glucose level. Here, we tested the hypothesis that ghrelin rises to prevent hypoglycemia in the absence of glucagon function. Both GcgR knockout (Gcgr-/-) mice and db/db mice that were administered GcgR monoclonal antibody displayed lower blood glucose levels accompanied by elevated plasma ghrelin levels. Although treatment with the pancreatic β-cell toxin streptozotocin induced hyperglycemia and raised plasma ghrelin levels in wild-type mice, hyperglycemia was averted in similarly treated Gcgr-/- mice and the plasma ghrelin level was further increased. Notably, administration of a ghrelin receptor antagonist further reduced blood glucose levels into the markedly hypoglycemic range in overnight-fasted, streptozotocin-treated Gcgr-/- mice. A lowered blood glucose level also was observed in overnight-fasted, streptozotocin-treated ghrelin receptor-null mice that were administered GcgR monoclonal antibody. These data suggest that when glucagon activity is blocked in the setting of type 1 diabetes, the plasma ghrelin level rises, preventing hypoglycemia.
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MESH Headings
- Animals
- Antibodies, Monoclonal/pharmacology
- Atenolol/pharmacology
- Blood Glucose/drug effects
- Blood Glucose/metabolism
- Cells, Cultured
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Type 1/genetics
- Diabetes Mellitus, Type 1/metabolism
- Gastric Mucosa/metabolism
- Ghrelin/metabolism
- Immunohistochemistry
- Insulin/metabolism
- Mice
- Mice, Knockout
- Oligopeptides/pharmacology
- Real-Time Polymerase Chain Reaction
- Receptors, Ghrelin/antagonists & inhibitors
- Receptors, Glucagon/antagonists & inhibitors
- Receptors, Glucagon/genetics
- Receptors, Leptin/genetics
- Sympatholytics/pharmacology
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Affiliation(s)
- Bharath K Mani
- Divisions of Hypothalamic Research and Endocrinology, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX
| | - Aki Uchida
- Advanced Imaging Center and Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Young Lee
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
| | - Sherri Osborne-Lawrence
- Divisions of Hypothalamic Research and Endocrinology, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX
| | - Maureen J Charron
- Departments of Biochemistry, Obstetrics and Gynecology and Woman's Health, and Medicine, Albert Einstein College of Medicine, Bronx, NY
| | - Roger H Unger
- Touchstone Diabetes Center, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX
| | - Eric D Berglund
- Advanced Imaging Center and Department of Pharmacology, University of Texas Southwestern Medical Center, Dallas, TX
| | - Jeffrey M Zigman
- Divisions of Hypothalamic Research and Endocrinology, Department of Internal Medicine and Department of Psychiatry, University of Texas Southwestern Medical Center, Dallas, TX
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30
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Kim J, Okamoto H, Huang Z, Anguiano G, Chen S, Liu Q, Cavino K, Xin Y, Na E, Hamid R, Lee J, Zambrowicz B, Unger R, Murphy AJ, Xu Y, Yancopoulos GD, Li WH, Gromada J. Amino Acid Transporter Slc38a5 Controls Glucagon Receptor Inhibition-Induced Pancreatic α Cell Hyperplasia in Mice. Cell Metab 2017; 25:1348-1361.e8. [PMID: 28591637 PMCID: PMC8206958 DOI: 10.1016/j.cmet.2017.05.006] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/21/2016] [Revised: 03/09/2017] [Accepted: 05/21/2017] [Indexed: 12/22/2022]
Abstract
Glucagon supports glucose homeostasis by stimulating hepatic gluconeogenesis, in part by promoting the uptake and conversion of amino acids into gluconeogenic precursors. Genetic disruption or pharmacologic inhibition of glucagon signaling results in elevated plasma amino acids and compensatory glucagon hypersecretion involving expansion of pancreatic α cell mass. Recent findings indicate that hyperaminoacidemia triggers pancreatic α cell proliferation via an mTOR-dependent pathway. We confirm and extend these findings by demonstrating that glucagon pathway blockade selectively increases expression of the sodium-coupled neutral amino acid transporter Slc38a5 in a subset of highly proliferative α cells and that Slc38a5 controls the pancreatic response to glucagon pathway blockade; most notably, mice deficient in Slc38a5 exhibit markedly decreased α cell hyperplasia to glucagon pathway blockade-induced hyperaminoacidemia. These results show that Slc38a5 is a key component of the feedback circuit between glucagon receptor signaling in the liver and amino-acid-dependent regulation of pancreatic α cell mass in mice.
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Affiliation(s)
- Jinrang Kim
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY 10591, USA
| | - Haruka Okamoto
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY 10591, USA
| | - ZhiJiang Huang
- Departments of Cell Biology and of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Guillermo Anguiano
- Departments of Cell Biology and of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Shiuhwei Chen
- Departments of Cell Biology and of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Qing Liu
- Departments of Cell Biology and of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | - Katie Cavino
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY 10591, USA
| | - Yurong Xin
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY 10591, USA
| | - Erqian Na
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY 10591, USA
| | - Rachid Hamid
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY 10591, USA
| | - Joseph Lee
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY 10591, USA
| | | | - Roger Unger
- Touchstone Center for Diabetes Research, Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | | | - Yan Xu
- Departments of Cell Biology and of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA
| | | | - Wen-Hong Li
- Departments of Cell Biology and of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX 75235, USA.
| | - Jesper Gromada
- Regeneron Pharmaceuticals, Inc., Tarrytown, NY 10591, USA.
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31
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Dean ED, Li M, Prasad N, Wisniewski SN, Von Deylen A, Spaeth J, Maddison L, Botros A, Sedgeman LR, Bozadjieva N, Ilkayeva O, Coldren A, Poffenberger G, Shostak A, Semich MC, Aamodt KI, Phillips N, Yan H, Bernal-Mizrachi E, Corbin JD, Vickers KC, Levy SE, Dai C, Newgard C, Gu W, Stein R, Chen W, Powers AC. Interrupted Glucagon Signaling Reveals Hepatic α Cell Axis and Role for L-Glutamine in α Cell Proliferation. Cell Metab 2017; 25:1362-1373.e5. [PMID: 28591638 PMCID: PMC5572896 DOI: 10.1016/j.cmet.2017.05.011] [Citation(s) in RCA: 147] [Impact Index Per Article: 21.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/20/2016] [Revised: 03/15/2017] [Accepted: 05/23/2017] [Indexed: 02/06/2023]
Abstract
Decreasing glucagon action lowers the blood glucose and may be useful therapeutically for diabetes. However, interrupted glucagon signaling leads to α cell proliferation. To identify postulated hepatic-derived circulating factor(s) responsible for α cell proliferation, we used transcriptomics/proteomics/metabolomics in three models of interrupted glucagon signaling and found that proliferation of mouse, zebrafish, and human α cells was mTOR and FoxP transcription factor dependent. Changes in hepatic amino acid (AA) catabolism gene expression predicted the observed increase in circulating AAs. Mimicking these AA levels stimulated α cell proliferation in a newly developed in vitro assay with L-glutamine being a critical AA. α cell expression of the AA transporter Slc38a5 was markedly increased in mice with interrupted glucagon signaling and played a role in α cell proliferation. These results indicate a hepatic α islet cell axis where glucagon regulates serum AA availability and AAs, especially L-glutamine, regulate α cell proliferation and mass via mTOR-dependent nutrient sensing.
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Affiliation(s)
- E Danielle Dean
- Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Mingyu Li
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA; School of Pharmaceutical Sciences, Xiamen University, Xiamen 361005, China
| | - Nripesh Prasad
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Scott N Wisniewski
- Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Alison Von Deylen
- Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Jason Spaeth
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Lisette Maddison
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Anthony Botros
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Leslie R Sedgeman
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Nadejda Bozadjieva
- Division of Metabolism, Endocrinology, and Diabetes, University of Michigan Health System, Ann Arbor, MI 48103, USA
| | - Olga Ilkayeva
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University, Durham, NC 27701, USA
| | - Anastasia Coldren
- Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Greg Poffenberger
- Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Alena Shostak
- Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Michael C Semich
- Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Kristie I Aamodt
- Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Neil Phillips
- Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Hai Yan
- REMD Biotherapeutics, Camarillo, CA 93012, USA
| | - Ernesto Bernal-Mizrachi
- Division of Endocrinology, Diabetes, and Metabolism, Department of Medicine, University of Miami, Miami, FL 33146, USA
| | - Jackie D Corbin
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Kasey C Vickers
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Division of Cardiovascular Medicine, Department of Medicine, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Shawn E Levy
- HudsonAlpha Institute for Biotechnology, Huntsville, AL 35806, USA
| | - Chunhua Dai
- Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Christopher Newgard
- Sarah W. Stedman Nutrition and Metabolism Center, Duke University, Durham, NC 27701, USA
| | - Wei Gu
- Amgen, Thousand Oaks, CA 91320, USA
| | - Roland Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Wenbiao Chen
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA
| | - Alvin C Powers
- Division of Diabetes, Endocrinology, and Metabolism, Vanderbilt University Medical Center, Nashville, TN 37232, USA; Department of Molecular Physiology and Biophysics, Vanderbilt University Medical Center, Nashville, TN 37232, USA; VA Tennessee Valley Healthcare, Nashville, TN 37212, USA.
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32
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Wu T, Horowitz M, Rayner CK. New insights into the anti-diabetic actions of metformin: from the liver to the gut. Expert Rev Gastroenterol Hepatol 2017; 11:157-166. [PMID: 27983877 DOI: 10.1080/17474124.2017.1273769] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Metformin is established as the first-line therapy for type 2 diabetes (T2DM), but its mode of action remains elusive. Elucidation of the mechanisms underlying the anti-diabetic action of metformin may have the potential to optimise its glucose-lowering efficacy and lead to the development of agents acting on novel targets for the management of type 2 diabetes. Areas covered: This review highlights key pharmacokinetic features of metformin, summarises recent insights into its hepatic and gastrointestinal actions relevant to blood glucose homeostasis, and discusses the common gastrointestinal side effects of metformin. Literature concerning these areas was reviewed on PubMed. Expert commentary: The mechanisms by which metformin improves glycaemic control in type 2 diabetes are complex. Although novel hepatic pathways continue to be reported in preclinical studies, there is a lack of human evidence for most of these. Considering the fundamental role of the gastrointestinal tract in the regulation of blood glucose homeostasis and pleiotropic actions of metformin on several gastrointestinal targets relevant to glycaemic control, the gut is likely to represent at least as important a site of metformin action as the liver in the management of type 2 diabetes.
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Affiliation(s)
- Tongzhi Wu
- a Discipline of Medicine and Centre of Research Excellence in Translating Nutritional Science to Good Health , The University of Adelaide , Adelaide , Australia
| | - Michael Horowitz
- a Discipline of Medicine and Centre of Research Excellence in Translating Nutritional Science to Good Health , The University of Adelaide , Adelaide , Australia
| | - Christopher K Rayner
- a Discipline of Medicine and Centre of Research Excellence in Translating Nutritional Science to Good Health , The University of Adelaide , Adelaide , Australia
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33
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Angptl4 does not control hyperglucagonemia or α-cell hyperplasia following glucagon receptor inhibition. Proc Natl Acad Sci U S A 2017; 114:2747-2752. [PMID: 28143927 DOI: 10.1073/pnas.1620989114] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/03/2023] Open
Abstract
Genetic disruption or pharmacologic inhibition of glucagon signaling effectively lowers blood glucose but results in compensatory glucagon hypersecretion involving expansion of pancreatic α-cell mass. Ben-Zvi et al. recently reported that angiopoietin-like protein 4 (Angptl4) links glucagon receptor inhibition to hyperglucagonemia and α-cell proliferation [Ben-Zvi et al. (2015) Proc Natl Acad Sci USA 112:15498-15503]. Angptl4 is a secreted protein and inhibitor of lipoprotein lipase-mediated plasma triglyceride clearance. We report that Angptl4-/- mice treated with an anti-glucagon receptor monoclonal antibody undergo elevation of plasma glucagon levels and α-cell expansion similar to wild-type mice. Overexpression of Angptl4 in liver of mice caused a 8.6-fold elevation in plasma triglyceride levels, but did not alter plasma glucagon levels or α-cell mass. Furthermore, administration of glucagon receptor-blocking antibody to healthy individuals increased plasma glucagon and amino acid levels, but did not change circulating Angptl4 concentration. These data show that Angptl4 does not link glucagon receptor inhibition to compensatory hyperglucagonemia or expansion of α-cell mass, and that it cannot be given to induce such secretion and growth. The reduction of plasma triglyceride levels in Angptl4-/- mice and increase following Angptl4 overexpression suggest that changes in plasma triglyceride metabolism do not regulate α-cells in the pancreas. Our findings corroborate recent data showing that increased plasma amino acids and their transport into α-cells link glucagon receptor blockage to α-cell hyperplasia.
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34
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Glucagon receptor inhibition normalizes blood glucose in severe insulin-resistant mice. Proc Natl Acad Sci U S A 2017; 114:2753-2758. [PMID: 28115707 DOI: 10.1073/pnas.1621069114] [Citation(s) in RCA: 52] [Impact Index Per Article: 7.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Inactivating mutations in the insulin receptor results in extreme insulin resistance. The resulting hyperglycemia is very difficult to treat, and patients are at risk for early morbidity and mortality from complications of diabetes. We used the insulin receptor antagonist S961 to induce severe insulin resistance, hyperglycemia, and ketonemia in mice. Using this model, we show that glucagon receptor (GCGR) inhibition with a monoclonal antibody normalized blood glucose and β-hydroxybutyrate levels. Insulin receptor antagonism increased pancreatic β-cell mass threefold. Normalization of blood glucose levels with GCGR-blocking antibody unexpectedly doubled β-cell mass relative to that observed with S961 alone and 5.8-fold over control. GCGR antibody blockage expanded α-cell mass 5.7-fold, and S961 had no additional effects. Collectively, these data show that GCGR antibody inhibition represents a potential therapeutic option for treatment of patients with extreme insulin-resistance syndromes.
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35
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Vajda EG, Logan D, Lasseter K, Armas D, Plotkin DJ, Pipkin JD, Li YX, Zhou R, Klein D, Wei X, Dilzer S, Zhi L, Marschke KB. Pharmacokinetics and pharmacodynamics of single and multiple doses of the glucagon receptor antagonist LGD-6972 in healthy subjects and subjects with type 2 diabetes mellitus. Diabetes Obes Metab 2017; 19:24-32. [PMID: 27501510 PMCID: PMC5215471 DOI: 10.1111/dom.12752] [Citation(s) in RCA: 36] [Impact Index Per Article: 5.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 07/26/2016] [Accepted: 07/27/2016] [Indexed: 01/21/2023]
Abstract
AIM To evaluate the safety, tolerability, pharmacokinetics and pharmacodynamics of single and multiple doses of a novel, oral glucagon receptor antagonist, LGD-6972, in healthy subjects and subjects with type 2 diabetes (T2DM). METHODS In the single ascending dose study, LGD-6972 (2-480 mg) was administered to healthy subjects (n = 48) and T2DM subjects (n = 8). In the multiple ascending dose study, healthy subjects (n = 12) received a dose of 15 mg LGD-6972 and T2DM subjects (n = 36) received doses of 5, 10 or 15 mg of LGD-6972 daily for 14 days. RESULTS LGD-6972 had linear plasma pharmacokinetics consistent with once-daily dosing that was comparable in healthy and T2DM subjects. Dose-dependent decreases in fasting plasma glucose were observed in all groups with a maximum of 3.15 mmol/L (56.8 mg/dL) on day 14 in T2DM subjects. LGD-6972 also reduced plasma glucose in the postprandial state. Dose-dependent increases in fasting plasma glucagon were observed, but glucagon levels decreased and insulin levels increased after an oral glucose load in T2DM subjects. LGD-6972 was well tolerated at the doses tested without dose-related or clinically meaningful changes in clinical laboratory parameters. No subject experienced hypoglycaemia. CONCLUSION Inhibition of glucagon action by LGD-6972 was associated with decreases in glucose in both healthy and T2DM subjects, the magnitude of which was sufficient to predict improvement in glycaemic control with longer treatment duration in T2DM patients. The safety and pharmacological profile of LGD-6972 after 14 days of dosing supports continued clinical development.
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Affiliation(s)
- Eric G. Vajda
- Ligand Pharmaceuticals IncorporatedSan DiegoCaliforniaUSA
| | - Douglas Logan
- Cincinnati VA Medical Center Ringgold Standard InstitutionCincinnatiOhioUSA
| | | | | | | | - JD Pipkin
- Ligand Pharmaceuticals IncorporatedSan DiegoCaliforniaUSA
| | | | | | | | | | - Stacy Dilzer
- Clinical Pharmacology of Miami, Inc.MiamiFloridaUSA
| | - Lin Zhi
- Ligand Pharmaceuticals IncorporatedSan DiegoCaliforniaUSA
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36
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Damond N, Thorel F, Moyers JS, Charron MJ, Vuguin PM, Powers AC, Herrera PL. Blockade of glucagon signaling prevents or reverses diabetes onset only if residual β-cells persist. eLife 2016; 5. [PMID: 27092792 PMCID: PMC4871705 DOI: 10.7554/elife.13828] [Citation(s) in RCA: 47] [Impact Index Per Article: 5.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2015] [Accepted: 04/07/2016] [Indexed: 12/15/2022] Open
Abstract
Glucagon secretion dysregulation in diabetes fosters hyperglycemia. Recent studies report that mice lacking glucagon receptor (Gcgr-/-) do not develop diabetes following streptozotocin (STZ)-mediated ablation of insulin-producing β-cells. Here, we show that diabetes prevention in STZ-treated Gcgr-/- animals requires remnant insulin action originating from spared residual β-cells: these mice indeed became hyperglycemic after insulin receptor blockade. Accordingly, Gcgr-/- mice developed hyperglycemia after induction of a more complete, diphtheria toxin (DT)-induced β-cell loss, a situation of near-absolute insulin deficiency similar to type 1 diabetes. In addition, glucagon deficiency did not impair the natural capacity of α-cells to reprogram into insulin production after extreme β-cell loss. α-to-β-cell conversion was improved in Gcgr-/- mice as a consequence of α-cell hyperplasia. Collectively, these results indicate that glucagon antagonism could i) be a useful adjuvant therapy in diabetes only when residual insulin action persists, and ii) help devising future β-cell regeneration therapies relying upon α-cell reprogramming. DOI:http://dx.doi.org/10.7554/eLife.13828.001 After meals, digested food causes sugar to accumulate in the blood. This triggers the release of the hormone insulin from beta cells in the pancreas, which allows liver cells, muscle cells and fat cells to use and store the sugar for energy. Other cells in the pancreas, called alpha cells, release a hormone called glucagon that counteracts the effects of insulin by telling the liver to release sugar into the bloodstream. The balance between the activity of insulin and glucagon keeps blood sugar levels steady. Diabetes results from the body being unable to produce enough insulin or respond to the insulin that is produced, which results in sugar accumulating in the blood. Diabetes also increases the production of glucagon, which further increases blood sugar levels. Recently, some researchers have reported that mice that lack the receptor proteins through which glucagon works do not develop diabetes, even when they are treated with a drug called streptozotocin that wipes out most of their beta cells. This suggests that the high blood sugar levels seen in diabetes result from an excess of glucagon, and not a lack of insulin. Drugs that block the action of glucagon have been found to reduce the symptoms of mild diabetes in mice and are now being tested in humans. However, it is less clear whether this treatment has any benefits in animals with more severe diabetes. Streptozotocin destroys most of a mouse’s beta cells but a significant fraction of them persist, while a different system relying on diphtheria toxin destroys more than 99% of these cells. Damond et al. have now found that treating mice that lack glucagon receptors with diphtheria toxin causes the mice to develop severe diabetes. Mice that lacked glucagon receptors that had been treated with streptozotocin also developed diabetes after they had been treated with an insulin-blocking drug. Further experiments showed that blocking glucagon receptors in typical mice with diabetes reduces blood sugar, but only if there is some insulin left in their bodies. Damond et al. also found that the glucagon receptor-lacking mice have more alpha cells, which have the ability to convert into insulin-producing cells after the widespread destruction of beta cells. Together, the experiments suggest that blocking glucagon could be a useful treatment for diabetes, but only in individuals who still have some insulin-producing cells. Such treatment would help reduce the release of sugar from the liver and increase the production of insulin in converted alpha cells in the pancreas. Damond et al. are now investigating how alpha cells convert into beta cells, with the aim of learning how to make beta cells regenerate more efficiently. DOI:http://dx.doi.org/10.7554/eLife.13828.002
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Affiliation(s)
- Nicolas Damond
- Department of Genetic Medicine and Development of the Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Institute of Genetics and Genomics in Geneva, University of Geneva, Geneva, Switzerland.,Centre facultaire du diabète, University of Geneva, Geneva, Switzerland
| | - Fabrizio Thorel
- Department of Genetic Medicine and Development of the Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Institute of Genetics and Genomics in Geneva, University of Geneva, Geneva, Switzerland.,Centre facultaire du diabète, University of Geneva, Geneva, Switzerland
| | - Julie S Moyers
- Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, United States
| | - Maureen J Charron
- Departments of Biochemistry, Medicine, and Obstetrics & Gynecology and Women's Health, Albert Einstein College of Medicine, Bronx, United States
| | - Patricia M Vuguin
- Pediatric Endocrinology, Women's and Childrens Health, College of Physicians & Surgeons, Columbia University, New York, United States
| | - Alvin C Powers
- Division of Diabetes, Endocrinology & Metabolism, Department of Medicine, Department of Molecular Physiology, Vanderbilt University, Nashville, United States.,VA Tennessee Valley Healthcare System, Nashville, United States
| | - Pedro L Herrera
- Department of Genetic Medicine and Development of the Faculty of Medicine, University of Geneva, Geneva, Switzerland.,Institute of Genetics and Genomics in Geneva, University of Geneva, Geneva, Switzerland.,Centre facultaire du diabète, University of Geneva, Geneva, Switzerland
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37
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Evans MR, Wei S, Posner BA, Unger RH, Roth MG. An AlphaScreen Assay for the Discovery of Synthetic Chemical Inhibitors of Glucagon Production. JOURNAL OF BIOMOLECULAR SCREENING 2016; 21:325-32. [PMID: 26676097 PMCID: PMC5226228 DOI: 10.1177/1087057115622201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/24/2015] [Accepted: 11/23/2015] [Indexed: 11/15/2022]
Abstract
Glucose homeostasis is primarily controlled by two opposing hormones, insulin and glucagon, and diabetes results when insulin fails to inhibit glucagon action. Recent efforts to control glucagon in diabetes have focused on antagonizing the glucagon receptor, which is effective in lowering blood glucose levels but leads to hyperglucogonemia in rodents. An alternative strategy would be to control glucagon production with small molecules. In pursuit of this goal, we developed a homogeneous AlphaScreen assay for measuring glucagon in cell culture media and used this in a high-throughput screen to discover synthetic compounds that inhibited glucagon secretion from an alpha cell-like cell line. Some of these compounds inhibited transcription of the glucagon gene.
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Affiliation(s)
- Matthew R Evans
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Shuguang Wei
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Bruce A Posner
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Roger H Unger
- Department of Internal Medicine, University of Texas Southwestern Medical Center, Dallas, TX, USA Department of Medical Service, Veteran's Administration North Texas Health Care System, Dallas, TX, USA
| | - Michael G Roth
- Department of Biochemistry, University of Texas Southwestern Medical Center, Dallas, TX, USA Touchstone Diabetes Center, University of Texas Southwestern Medical Center, Dallas, TX, USA
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38
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Abstract
OBJECTIVE There is general recognition that insulin and glucagon are the main hormones involved in the pathophysiology of diabetes, but the role of glucagon in diabetes is complex and in some circumstances controversial. The increasing appreciation of the role of glucagon in currently used hypoglycemic agents and the ongoing development of glucagon-targeted therapies underscores glucagon's important contribution in optimizing diabetes management. The current review provides a background on glucagon physiology and pathophysiology and an update for investigators, endocrinologists, and other healthcare providers on glucagon-modulating therapies. METHODS A literature review was conducted utilizing published literature in PubMed and AccessMedicine including the years 1922-2015 using the following key words: glucagon, bihormonal, diabetes mellitus, glucagon antagonists, glucagon-targeted therapies. RESULTS Glucagon is a counterregulatory hormone that promotes hepatic glucose production, thus preventing hypoglycemia in normal physiology. In patients with diabetes mellitus, glucagon secretion may be unregulated, which contributes to problems with glucose homeostasis. Several of the most effective therapies for diabetes have been found to suppress glucagon secretion or action, which may contribute to their success. Additionally, glucagon-specific targeted therapies, such as glucagon receptor antagonists, are being studied at a basic and clinical level. CONCLUSION Glucagon plays an important role in contributing to hyperglycemia in patients with diabetes. Utilizing hypoglycemic agents that decrease glucagon secretion or inhibit glucagon action can help improve glycemic control, making these agents a valuable resource in diabetes therapy.
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39
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Abstract
The alpha cells that co-occupy the islets in association with beta cells have been long recognized as the source of glucagon, a hyperglycemia-producing and diabetogenic hormone. Although the mechanisms that control the functions of alpha cells, glucagon secretion, and the role of glucagon in diabetes have remained somewhat enigmatic over the fifty years since their discovery, seminal findings during the past few years have moved alpha cells into the spotlight of scientific discovery. These findings obtained largely from studies in mice are: Alpha cells have the capacity to trans-differentiate into insulin-producing beta cells. Alpha cells contain a GLP-1 generating system that produces GLP-1 locally for paracrine actions within the islets that likely promotes beta cell growth and survival and maintains beta cell mass. Impairment of glucagon signaling both prevents the occurrence of diabetes in conditions of the near absence of insulin and expands alpha cell mass. Alpha cells appear to serve as helper cells or guardians of beta cells to ensure their health and well-being. Of potential relevance to the possibility of promoting the transformation of alpha to beta cells is the observation that impairment of glucagon signaling leads to a marked increase in alpha cell mass in the islets. Such alpha cell hyperplasia provides an increased supply of alpha cells for their transdifferentiation into new beta cells. In this review we discuss these recent discoveries from the perspective of their potential relevance to the treatment of diabetes.
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Affiliation(s)
- Violeta Stanojevic
- Laboratory of Molecular Endocrinology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA
| | - Joel F Habener
- Laboratory of Molecular Endocrinology, Department of Medicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.
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40
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Guan HP, Yang X, Lu K, Wang SP, Castro-Perez JM, Previs S, Wright M, Shah V, Herath K, Xie D, Szeto D, Forrest G, Xiao JC, Palyha O, Sun LP, Andryuk PJ, Engel SS, Xiong Y, Lin S, Kelley DE, Erion MD, Davis HR, Wang L. Glucagon receptor antagonism induces increased cholesterol absorption. J Lipid Res 2015; 56:2183-95. [PMID: 26373568 DOI: 10.1194/jlr.m060897] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2015] [Indexed: 12/26/2022] Open
Abstract
Glucagon and insulin have opposing action in governing glucose homeostasis. In type 2 diabetes mellitus (T2DM), plasma glucagon is characteristically elevated, contributing to increased gluconeogenesis and hyperglycemia. Therefore, glucagon receptor (GCGR) antagonism has been proposed as a pharmacologic approach to treat T2DM. In support of this concept, a potent small-molecule GCGR antagonist (GRA), MK-0893, demonstrated dose-dependent efficacy to reduce hyperglycemia, with an HbA1c reduction of 1.5% at the 80 mg dose for 12 weeks in T2DM. However, GRA treatment was associated with dose-dependent elevation of plasma LDL-cholesterol (LDL-c). The current studies investigated the cause for increased LDL-c. We report findings that link MK-0893 with increased glucagon-like peptide 2 and cholesterol absorption. There was not, however, a GRA-related modulation of cholesterol synthesis. These findings were replicated using structurally diverse GRAs. To examine potential pharmacologic mitigation, coadministration of ezetimibe (a potent inhibitor of cholesterol absorption) in mice abrogated the GRA-associated increase of LDL-c. Although the molecular mechanism is unknown, our results provide a novel finding by which glucagon and, hence, GCGR antagonism govern cholesterol metabolism.
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Affiliation(s)
- Hong-Ping Guan
- Departments of Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Xiaodong Yang
- Departments of Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Ku Lu
- Departments of Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Sheng-Ping Wang
- Departments of Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Jose M Castro-Perez
- Departments of Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Stephen Previs
- Departments of Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Michael Wright
- Late Stage In Vitro Pharmacology, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Vinit Shah
- Departments of Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Kithsiri Herath
- Departments of Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Dan Xie
- Departments of Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Daphne Szeto
- Late Stage In Vivo Pharmacology, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Gail Forrest
- Late Stage In Vivo Pharmacology, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Jing Chen Xiao
- Departments of Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Oksana Palyha
- Departments of Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Li-Ping Sun
- Departments of Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Paula J Andryuk
- Clinical Research Department, Merck Research Laboratories, Rahway, NJ 07065
| | - Samuel S Engel
- Clinical Research Department, Merck Research Laboratories, Rahway, NJ 07065
| | - Yusheng Xiong
- Discovery Chemistry, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Songnian Lin
- Discovery Chemistry, Merck Research Laboratories, Kenilworth, NJ 07033
| | - David E Kelley
- Departments of Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Mark D Erion
- Departments of Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Harry R Davis
- Departments of Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, NJ 07033
| | - Liangsu Wang
- Departments of Cardiometabolic Disease, Merck Research Laboratories, Kenilworth, NJ 07033
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Spaeth JM, Hunter CS, Bonatakis L, Guo M, French CA, Slack I, Hara M, Fisher SE, Ferrer J, Morrisey EE, Stanger BZ, Stein R. The FOXP1, FOXP2 and FOXP4 transcription factors are required for islet alpha cell proliferation and function in mice. Diabetologia 2015; 58:1836-44. [PMID: 26021489 PMCID: PMC4785827 DOI: 10.1007/s00125-015-3635-3] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/04/2015] [Accepted: 04/28/2015] [Indexed: 12/11/2022]
Abstract
AIMS/HYPOTHESIS Several forkhead box (FOX) transcription factor family members have important roles in controlling pancreatic cell fates and maintaining beta cell mass and function, including FOXA1, FOXA2 and FOXM1. In this study we have examined the importance of FOXP1, FOXP2 and FOXP4 of the FOXP subfamily in islet cell development and function. METHODS Mice harbouring floxed alleles for Foxp1, Foxp2 and Foxp4 were crossed with pan-endocrine Pax6-Cre transgenic mice to generate single and compound Foxp mutant mice. Mice were monitored for changes in glucose tolerance by IPGTT, serum insulin and glucagon levels by radioimmunoassay, and endocrine cell development and proliferation by immunohistochemistry. Gene expression and glucose-stimulated hormone secretion experiments were performed with isolated islets. RESULTS Only the triple-compound Foxp1/2/4 conditional knockout (cKO) mutant had an overt islet phenotype, manifested physiologically by hypoglycaemia and hypoglucagonaemia. This resulted from the reduction in glucagon-secreting alpha cell mass and function. The proliferation of alpha cells was profoundly reduced in Foxp1/2/4 cKO islets through the effects on mediators of replication (i.e. decreased Ccna2, Ccnb1 and Ccnd2 activators, and increased Cdkn1a inhibitor). Adult islet Foxp1/2/4 cKO beta cells secrete insulin normally while the remaining alpha cells have impaired glucagon secretion. CONCLUSIONS/INTERPRETATION Collectively, these findings reveal an important role for the FOXP1, 2, and 4 proteins in governing postnatal alpha cell expansion and function.
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Affiliation(s)
- Jason M. Spaeth
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical School, 723 Light Hall, 2215 Garland Avenue, Nashville, TN 37232, USA
| | - Chad S. Hunter
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical School, 723 Light Hall, 2215 Garland Avenue, Nashville, TN 37232, USA
- Department of Medicine, Division of Endocrinology Diabetes & Metabolism, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Lauren Bonatakis
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical School, 723 Light Hall, 2215 Garland Avenue, Nashville, TN 37232, USA
| | - Min Guo
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical School, 723 Light Hall, 2215 Garland Avenue, Nashville, TN 37232, USA
| | - Catherine A. French
- Champalimaud Neuroscience Programme, Champalimaud Centre for the Unknown, Lisbon, Portugal
| | - Ian Slack
- Department of Medicine and Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Manami Hara
- Department of Medicine, University of Chicago, Chicago, IL, USA
| | - Simon E. Fisher
- Language and Genetics Department, Max Planck Institute for Psycholinguistics, Nijmegen, The Netherlands
- Donders Institute for Brain, Cognition and Behaviour, Radboud University, Nijmegen, The Netherlands
| | - Jorge Ferrer
- Department of Medicine, Imperial Centre for Translational and Experimental Medicine, Imperial College London, London, UK
| | - Edward E. Morrisey
- Department of Medicine and Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Ben Z. Stanger
- Department of Medicine and Cell and Developmental Biology, University of Pennsylvania, Philadelphia, PA, USA
| | - Roland Stein
- Department of Molecular Physiology and Biophysics, Vanderbilt University Medical School, 723 Light Hall, 2215 Garland Avenue, Nashville, TN 37232, USA
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42
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Solloway M, Madjidi A, Gu C, Eastham-Anderson J, Clarke H, Kljavin N, Zavala-Solorio J, Kates L, Friedman B, Brauer M, Wang J, Fiehn O, Kolumam G, Stern H, Lowe J, Peterson A, Allan B. Glucagon Couples Hepatic Amino Acid Catabolism to mTOR-Dependent Regulation of α-Cell Mass. Cell Rep 2015; 12:495-510. [DOI: 10.1016/j.celrep.2015.06.034] [Citation(s) in RCA: 95] [Impact Index Per Article: 10.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/06/2014] [Revised: 03/27/2015] [Accepted: 06/09/2015] [Indexed: 02/08/2023] Open
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Kelly RP, Garhyan P, Raddad E, Fu H, Lim CN, Prince MJ, Pinaire JA, Loh MT, Deeg MA. Short-term administration of the glucagon receptor antagonist LY2409021 lowers blood glucose in healthy people and in those with type 2 diabetes. Diabetes Obes Metab 2015; 17:414-22. [PMID: 25656305 DOI: 10.1111/dom.12446] [Citation(s) in RCA: 86] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/06/2014] [Revised: 01/29/2015] [Accepted: 01/31/2015] [Indexed: 11/30/2022]
Abstract
AIM To describe the clinical effects of single and multiple doses of a potent, selective, orally administered, small-molecule antagonist of the human glucagon receptor, LY2409021, in healthy subjects and in patients with type 2 diabetes. METHODS LY2409021 was administered in dose-escalation studies to healthy subjects (n = 23) and patients with type 2 diabetes (n = 9) as single doses (Study 1) and daily to patients with type 2 diabetes (n = 47) for 28 days (Study 2). Safety, tolerability, pharmacokinetic (PK) and pharmacodynamic (PD) assessments were made after single doses and in patients receiving once-daily doses of LY2409021 (5, 30, 60 or 90 mg) for 28 days. RESULTS LY2409021 was well tolerated at all dose levels in both studies. Fasting and postprandial glucose were reduced and glucagon levels increased after single and multiple dosing, with reductions in fasting serum glucose of up to ∼1.25 mmol/l on day 28. Serum aminotransferases increased in a dose-dependent manner with multiple dosing and reversed after cessation of dosing. Significant glucose-lowering was observed with LY2409021 at dose levels associated with only minor aminotransferase increases. CONCLUSION Blockade of glucagon signalling in patients with type 2 diabetes is well tolerated and results in substantial reduction of fasting and postprandial glucose with minimal hypoglycaemia, but with reversible increases in aminotransferases. Inhibition of glucagon signalling by LY2409021 is a promising potential treatment for patients with type 2 diabetes and should be evaluated in longer clinical trials to better evaluate benefits and risks.
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Affiliation(s)
- R P Kelly
- Lilly-NUS, Clinical Research Centre, National University of Singapore, 10 Medical Drive, 117597, Singapore
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44
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Jun LS, Millican RL, Hawkins ED, Konkol DL, Showalter AD, Christe ME, Michael MD, Sloop KW. Absence of glucagon and insulin action reveals a role for the GLP-1 receptor in endogenous glucose production. Diabetes 2015; 64:819-27. [PMID: 25288673 DOI: 10.2337/db14-1052] [Citation(s) in RCA: 45] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
The absence of insulin results in oscillating hyperglycemia and ketoacidosis in type 1 diabetes. Remarkably, mice genetically deficient in the glucagon receptor (Gcgr) are refractory to the pathophysiological symptoms of insulin deficiency, and therefore, studies interrogating this unique model may uncover metabolic regulatory mechanisms that are independent of insulin. A significant feature of Gcgr-null mice is the high circulating concentrations of GLP-1. Hence, the objective of this report was to investigate potential noninsulinotropic roles of GLP-1 in mice where GCGR signaling is inactivated. For these studies, pancreatic β-cells were chemically destroyed by streptozotocin (STZ) in Gcgr(-/-):Glp-1r(-/-) mice and in Glp-1r(-/-) animals that were subsequently treated with a high-affinity GCGR antagonist antibody that recapitulates the physiological state of Gcgr ablation. Loss of GLP-1 action substantially worsened nonfasting glucose concentrations and glucose tolerance in mice deficient in, and undergoing pharmacological inhibition of, the GCGR. Further, lack of the Glp-1r in STZ-treated Gcgr(-/-) mice elevated rates of endogenous glucose production, likely accounting for the differences in glucose homeostasis. These results support the emerging hypothesis that non-β-cell actions of GLP-1 analogs may improve metabolic control in patients with insulinopenic diabetes.
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Affiliation(s)
- Lucy S Jun
- Endocrine Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Rohn L Millican
- BioTechnology Discovery Research, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Eric D Hawkins
- Endocrine Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Debra L Konkol
- Endocrine Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Aaron D Showalter
- Endocrine Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Michael E Christe
- Endocrine Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - M Dodson Michael
- Endocrine Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
| | - Kyle W Sloop
- Endocrine Discovery, Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, IN
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45
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Abstract
Glucagon action is transduced by a G protein-coupled receptor located in liver, kidney, intestinal smooth muscle, brain, adipose tissue, heart, pancreatic β-cells, and placenta. Genetically modified animal models have provided important clues about the role of glucagon and its receptor (Gcgr) beyond glucose control. The PubMed database was searched for articles published between 1995 and 2014 using the key terms glucagon, glucagon receptor, signaling, and animal models. Lack of Gcgr signaling has been associated with: i) hypoglycemic pregnancies, altered placentation, poor fetal growth, and increased fetal-neonatal death; ii) pancreatic glucagon cell hyperplasia and hyperglucagonemia; iii) altered body composition, energy state, and protection from diet-induced obesity; iv) impaired hepatocyte survival; v) altered glucose, lipid, and hormonal milieu; vi) altered metabolic response to prolonged fasting and exercise; vii) reduced gastric emptying and increased intestinal length; viii) altered retinal function; and ix) prevention of the development of diabetes in insulin-deficient mice. Similar phenotypic findings were observed in the hepatocyte-specific deletion of Gcgr. Glucagon action has been involved in the modulation of sweet taste responsiveness, inotropic and chronotropic effects in the heart, satiety, glomerular filtration rate, secretion of insulin, cortisol, ghrelin, GH, glucagon, and somatostatin, and hypothalamic signaling to suppress hepatic glucose production. Glucagon (α) cells under certain conditions can transdifferentiate into insulin (β) cells. These findings suggest that glucagon signaling plays an important role in multiple organs. Thus, treatment options designed to block Gcgr activation in diabetics may have implications beyond glucose homeostasis.
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Affiliation(s)
- Maureen J Charron
- Departments of BiochemistryObstetrics and Gynecology and Women's HealthMedicineAlbert Einstein College of Medicine, 1300 Morris Park Avenue, F312, Bronx, New York 10461, USADepartment of PediatricsHofstra School of Medicine, Cohen Children's Medical Center, 1991 Marcus Avenue, Lake Success, New York 11402, USA Departments of BiochemistryObstetrics and Gynecology and Women's HealthMedicineAlbert Einstein College of Medicine, 1300 Morris Park Avenue, F312, Bronx, New York 10461, USADepartment of PediatricsHofstra School of Medicine, Cohen Children's Medical Center, 1991 Marcus Avenue, Lake Success, New York 11402, USA Departments of BiochemistryObstetrics and Gynecology and Women's HealthMedicineAlbert Einstein College of Medicine, 1300 Morris Park Avenue, F312, Bronx, New York 10461, USADepartment of PediatricsHofstra School of Medicine, Cohen Children's Medical Center, 1991 Marcus Avenue, Lake Success, New York 11402, USA
| | - Patricia M Vuguin
- Departments of BiochemistryObstetrics and Gynecology and Women's HealthMedicineAlbert Einstein College of Medicine, 1300 Morris Park Avenue, F312, Bronx, New York 10461, USADepartment of PediatricsHofstra School of Medicine, Cohen Children's Medical Center, 1991 Marcus Avenue, Lake Success, New York 11402, USA
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Glucagon receptor antibody completely suppresses type 1 diabetes phenotype without insulin by disrupting a novel diabetogenic pathway. Proc Natl Acad Sci U S A 2015; 112:2503-8. [PMID: 25675519 DOI: 10.1073/pnas.1424934112] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/18/2022] Open
Abstract
Insulin monotherapy can neither maintain normoglycemia in type 1 diabetes (T1D) nor prevent the long-term damage indicated by elevated glycation products in blood, such as glycated hemoglobin (HbA1c). Here we find that hyperglycemia, when unaccompanied by an acute increase in insulin, enhances itself by paradoxically stimulating hyperglucagonemia. Raising glucose from 5 to 25 mM without insulin enhanced glucagon secretion ∼two- to fivefold in InR1-G9 α cells and ∼18-fold in perfused pancreata from insulin-deficient rats with T1D. Mice with T1D receiving insulin treatment paradoxically exhibited threefold higher plasma glucagon during hyperglycemic surges than during normoglycemic intervals. Blockade of glucagon action with mAb Ac, a glucagon receptor (GCGR) antagonizing antibody, maintained glucose below 100 mg/dL and HbA1c levels below 4% in insulin-deficient mice with T1D. In rodents with T1D, hyperglycemia stimulates glucagon secretion, up-regulating phosphoenolpyruvate carboxykinase and enhancing hyperglycemia. GCGR antagonism in mice with T1D normalizes glucose and HbA1c, even without insulin.
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47
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O'Harte FPM, Franklin ZJ, Irwin N. Two novel glucagon receptor antagonists prove effective therapeutic agents in high-fat-fed and obese diabetic mice. Diabetes Obes Metab 2014; 16:1214-22. [PMID: 25060150 DOI: 10.1111/dom.12360] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2014] [Revised: 07/03/2014] [Accepted: 07/19/2014] [Indexed: 11/30/2022]
Abstract
AIMS To examine the effect of two novel, enzymatically stable, glucagon receptor peptide antagonists, on metabolic control in two mouse models of obesity/diabetes. METHOD The effects of twice daily i.p. administration of desHis(1)Pro(4)Glu(9)-glucagon or desHis(1)Pro(4)Glu(9)Lys(12)FA-glucagon for 10 days on metabolic control in high-fat-fed (HFF; 45% fat) and obese diabetic (ob/ob) mice were compared with saline-treated controls. RESULTS Neither analogue altered body weight or food intake in either model over 10 days; however, treatment with each peptide restored non-fasting blood glucose towards normal control values in HFF mice. Basal glucose was also reduced (p < 0.01) in desHis(1)Pro(4)Glu(9)Lys(12)FA-glucagon treated ob/ob mice by day 10, coinciding with increases (p < 0.001) in circulating insulin. At the end of the treatment period, both analogues significantly (p < 0.05-0.01) improved oral and i.p. glucose tolerance (p < 0.05) and peripheral insulin sensitivity, increased pancreatic insulin and glucagon content (p < 0.05-0.01) and decreased (p < 0.05) cholesterol levels in HFF mice. Similarly beneficial metabolic effects on oral glucose tolerance (p < 0.01) and pancreatic insulin content (p < 0.05) were observed in ob/ob mice, especially after desHis(1)Pro(4)Glu(9)Lys(12)FA-glucagon treatment. No significant differences in circulating triglycerides or aspects of indirect calorimetry were noted between peptide treatment groups and respective control HFF and ob/ob mice. Finally, glucagon-mediated elevations of glucose and insulin were significantly (p < 0.05-0.01) annulled after 10 days of desHis(1)Pro(4)Glu(9)-glucagon or desHis(1)Pro(4)Glu(9)Lys(12)FA-glucagon treatment in both animal models. CONCLUSION These data indicate that peptide-based glucagon receptor antagonists can reverse aspects of genetically and dietary-induced obesity-related diabetes.
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Affiliation(s)
- F P M O'Harte
- The Saad Centre for Pharmacy & Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, UK
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48
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McShane LM, Franklin ZJ, O'Harte FPM, Irwin N. Ablation of glucagon receptor signaling by peptide-based glucagon antagonists improves glucose tolerance in high fat fed mice. Peptides 2014; 60:95-101. [PMID: 25148830 DOI: 10.1016/j.peptides.2014.08.002] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2014] [Revised: 08/06/2014] [Accepted: 08/06/2014] [Indexed: 01/21/2023]
Abstract
Modification to the structure of glucagon has provided a number of glucagon receptor antagonists with possible therapeutic application for diabetes. These novel peptide analogs include desHis(1)Pro(4)Glu(9)-glucagon and desHis(1)Pro(4)Glu(9)(Lys(30)PAL)-glucagon. This study has evaluated the metabolic benefits of once daily administration of desHis(1)Pro(4)Glu(9)-glucagon and desHis(1)Pro(4)Glu(9)(Lys(30)PAL)-glucagon in high fat (45%) fed mice for 15 days. Administration of desHis(1)Pro(4)Glu(9)-glucagon and desHis(1)Pro(4)Glu(9)(Lys(30)PAL)-glucagon had no significant effect on body weight, food intake or circulating glucose concentrations during the treatment period. However, both peptides significantly (P<0.05 to P<0.01) reduced circulating plasma insulin concentrations from day 6 onwards. Oral glucose tolerance and insulin sensitivity, as assessed by exogenous insulin administration, were significantly (P<0.01 to P<0.001) improved by both desHis(1)Pro(4)Glu(9)-glucagon and desHis(1)Pro(4)Glu(9)(Lys(30)PAL)-glucagon. These metabolic benefits were accompanied by significantly (P<0.01) increased pancreatic insulin stores. No significant differences in blood triacylglycerol or cholesterol levels were noted with desHis(1)Pro(4)Glu(9)-glucagon, however desHis(1)Pro(4)Glu(9)(Lys(30)PAL)-glucagon treatment significantly (P<0.01) increased HDL-cholesterol levels. Glucagon-mediated elevations of glucose and insulin were effectively (P<0.01 to P<0.001) annulled in both treatment groups on day 15. Interestingly, glucose levels during an intraperitoneal glucose tolerance test were not altered by either desHis(1)Pro(4)Glu(9)-glucagon or desHis(1)Pro(4)Glu(9)(Lys(30)PAL)-glucagon treatment. These data provide further evidence that glucagon antagonism could provide an effective means of treating T2DM.
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Affiliation(s)
- Laura M McShane
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK
| | - Zara J Franklin
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK
| | - Finbarr P M O'Harte
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK.
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49
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Wu T, Ma J, Bound MJ, Checklin H, Deacon CF, Jones KL, Horowitz M, Rayner CK. Effects of sitagliptin on glycemia, incretin hormones, and antropyloroduodenal motility in response to intraduodenal glucose infusion in healthy lean and obese humans and patients with type 2 diabetes treated with or without metformin. Diabetes 2014; 63:2776-87. [PMID: 24647737 DOI: 10.2337/db13-1627] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
The impact of variations in gastric emptying, which influence the magnitude of glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) secretion, on glucose lowering by dipeptidyl peptidase-4 (DPP-4) inhibitors is unclear. We evaluated responses to intraduodenal glucose infusion (60 g over 120 min [i.e., 2 kcal/min], a rate that predominantly stimulates GIP but not GLP-1) after sitagliptin versus control in 12 healthy lean, 12 obese, and 12 type 2 diabetic subjects taking metformin 850 mg b.i.d. versus placebo. As expected, sitagliptin augmented plasma-intact GIP substantially and intact GLP-1 modestly. Sitagliptin attenuated glycemic excursions in healthy lean and obese but not type 2 diabetic subjects, without affecting glucagon or energy intake. In contrast, metformin reduced fasting and glucose-stimulated glycemia, suppressed energy intake, and augmented total and intact GLP-1, total GIP, and glucagon in type 2 diabetic subjects, with no additional glucose lowering when combined with sitagliptin. These observations indicate that in type 2 diabetes, 1) the capacity of endogenous GIP to lower blood glucose is impaired; 2) the effect of DPP-4 inhibition on glycemia is likely to depend on adequate endogenous GLP-1 release, requiring gastric emptying >2 kcal/min; and 3) the action of metformin to lower blood glucose is not predominantly by way of the incretin axis.
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Affiliation(s)
- Tongzhi Wu
- Discipline of Medicine, University of Adelaide, Adelaide, SA, AustraliaCentre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, SA, Australia
| | - Jing Ma
- Discipline of Medicine, University of Adelaide, Adelaide, SA, AustraliaCentre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, SA, Australia
| | - Michelle J Bound
- Discipline of Medicine, University of Adelaide, Adelaide, SA, AustraliaCentre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, SA, Australia
| | - Helen Checklin
- Discipline of Medicine, University of Adelaide, Adelaide, SA, AustraliaCentre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, SA, Australia
| | - Carolyn F Deacon
- Department of Biomedical Science, University of Copenhagen, Copenhagen, Denmark
| | - Karen L Jones
- Discipline of Medicine, University of Adelaide, Adelaide, SA, AustraliaCentre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, SA, Australia
| | - Michael Horowitz
- Discipline of Medicine, University of Adelaide, Adelaide, SA, AustraliaCentre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, SA, Australia
| | - Christopher K Rayner
- Discipline of Medicine, University of Adelaide, Adelaide, SA, AustraliaCentre of Research Excellence in Translating Nutritional Science to Good Health, University of Adelaide, Adelaide, SA, Australia
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50
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Franklin ZJ, O’Harte FP, Irwin N. Effects of short-term chemical ablation of glucagon signalling by peptide-based glucagon receptor antagonists on insulin secretion and glucose homeostasis in mice. Biol Chem 2014; 395:433-42. [DOI: 10.1515/hsz-2013-0224] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2013] [Accepted: 11/04/2013] [Indexed: 11/15/2022]
Abstract
Abstract
Glucagon is a hormone with important effects on blood glucose regulation. This study has utilized the stable glucagon receptor antagonists, desHis1Pro4Glu9-glucagon and desHis1Pro4Glu9(Lys12PAL)-glucagon, to evaluate the effects of sustained inhibition of glucagon receptor signalling in normal mice. Twice-daily injection of either analogue for 10 days had no effect on food intake, body weight and non-fasting plasma glucose concentrations. However, insulin levels were significantly raised (p<0.05 to p<0.01) from day 3 onwards in desHis1Pro4Glu9-glucagon mice. After 10 days, glucose tolerance was improved (p<0.05) in desHis1Pro4Glu9-glucagon treated mice. Glucose-mediated insulin secretion and circulating cholesterol levels were significantly (p<0.05 to p<0.01) decreased in both treatment groups. Importantly, the effects of glucagon to increase blood glucose and insulin concentrations were still annulled on day 10. Insulin sensitivity was almost identical in all groups of mice at the end of the study. In addition, no changes in pancreatic insulin and glucagon content or islet morphology were observed in either treatment group. Finally, acute injection of desHis1Pro4Glu9-glucagon followed by a 24-h fast in treatment naïve mice was not associated with any hypoglycaemic episodes. These data indicate that peptide-based glucagon receptor antagonists represent safe and effective treatment options for type 2 diabetes.
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