1
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Das S, Ravi H, Babu A, Banerjee M, Kanagavalli R, Dhanasekaran S, Devi Rajeswari V, Venkatraman G, Ramanathan G. Therapeutic potentials of glucose-dependent insulinotropic polypeptide (GIP) in T2DM: Past, present, and future. ADVANCES IN PROTEIN CHEMISTRY AND STRUCTURAL BIOLOGY 2024; 142:293-328. [PMID: 39059989 DOI: 10.1016/bs.apcsb.2023.12.017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/28/2024]
Abstract
Type 2 diabetes mellitus (T2DM) is a worldwide health problem that has raised major concerns to the public health community. This chronic condition typically results from the cell's inability to respond to normal insulin levels. Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are the primary incretin hormones secreted from the intestinal tract. While clinical research has extensively explored the therapeutic potential of GLP-1R in addressing various T2DM-related abnormalities, the possibility of GIPR playing an important role in T2DM treatment is still under investigation. Evidence suggests that GIP is involved in the pathophysiology of T2DM. This chapter focuses on examining the role of GIP as a therapeutic molecule in combating T2DM, comparing the past, present, and future scenarios. Our goal is to delve into how GIP may impact pancreatic β-cell function, adipose tissue uptake, and lipid metabolism. Furthermore, we will elucidate the mechanistic functions of GIP and its receptors in relation to other clinical conditions like cardiovascular diseases, non-alcoholic fatty liver diseases, neurodegenerative diseases, and renal disorders. Additionally, this chapter will shed light on the latest advancements in pharmacological management for T2DM, highlighting potential structural modifications of GIP and the repurposing of drugs, while also addressing the challenges involved in bringing GIP-based treatments into clinical practice.
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Affiliation(s)
- Soumik Das
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Harini Ravi
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Achsha Babu
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Manosi Banerjee
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - R Kanagavalli
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Sivaraman Dhanasekaran
- School of Energy Technology, Pandit Deendayal Energy University, Knowledge Corridor, Gandhinagar, Gujarat, India
| | - V Devi Rajeswari
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Ganesh Venkatraman
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India
| | - Gnanasambandan Ramanathan
- Department of Bio-Medical Sciences, School of Bio Sciences and Technology, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu, India.
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2
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A simple self-assembling system of melittin for hepatoma treatment. Cancer Nanotechnol 2023. [DOI: 10.1186/s12645-022-00154-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023] Open
Abstract
Abstract
Background
Hepatoma is a serious public health concern. New attempts are urgently needed to solve this problem. Melittin, a host defense peptide derived from the venom of honeybees, has noteworthy hemolysis and non-specific cytotoxicity in clinical applications. Here, the self-assembly of melittin and vitamin E-succinic acid-(glutamate)12 (VG) was fabricated via noncovalent π-stacking and hydrogen bonding interactions using an environment-friendly method without “toxic” solvents.
Results
As expected, the designed self-assembly (denoted as M/VG nanoparticles) exhibits a uniform morphology with a particle size of approximately 60 nm and a zeta potential of approximately − 26.8 mV. Furthermore, added VG significantly decreased hemolytic activity, increased tumor-targeted effects, and accelerated apoptosis.
Conclusion
Our research provides a promising strategy for the development of natural self-assembled biological peptides for clinical application, particularly for transforming toxic peptides into safe therapeutic systems.
Graphical Abstract
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3
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Ding X, Wang Y, Zhang S, Zhang R, Chen D, Chen L, Zhang Y, Luo SZ, Xu J, Pei C. Self-Assembly Nanostructure of Myristoylated ω-Conotoxin MVIIA Increases the Duration of Efficacy and Reduces Side Effects. Mar Drugs 2023; 21:md21040229. [PMID: 37103368 PMCID: PMC10144222 DOI: 10.3390/md21040229] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2023] [Revised: 03/28/2023] [Accepted: 03/30/2023] [Indexed: 04/05/2023] Open
Abstract
Chronic pain is one of the most prevalent health problems worldwide. An alternative to suppress or alleviate chronic pain is the use of peptide drugs that block N-type Ca2+ channels (Cav2.2), such as ω-conotoxin MVIIA. Nevertheless, the narrow therapeutic window, severe neurological side effects and low stability associated with peptide MVIIA have restricted its widespread use. Fortunately, self-assembly endows the peptide with high stability and multiple functions, which can effectively control its release to prolong its duration of action. Inspired by this, MVIIA was modified with appropriate fatty acid chains to render it amphiphilic and easier to self-assemble. In this paper, an N-terminal myristoylated MVIIA (Myr-MVIIA, medium carbon chain length) was designed and prepared to undergo self-assembly. The present results indicated that Myr-MVIIA can self-assemble into micelles. Self-assembled micelles formed by Myr-MVIIA at higher concentrations than MVIIA can prolong the duration of the analgesic effect and significantly reduce or even eliminate the side effects of tremor and coordinated motor dysfunction in mice.
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Affiliation(s)
- Xiufang Ding
- State key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Yue Wang
- State key Laboratory of NBC Protection for Civilian, Beijing 102205, China
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Sida Zhang
- State key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Ruihua Zhang
- State key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Dong Chen
- State key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Long Chen
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Yu Zhang
- State key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Shi-Zhong Luo
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology, Beijing University of Chemical Technology, Beijing 100029, China
| | - Jianfu Xu
- State key Laboratory of NBC Protection for Civilian, Beijing 102205, China
| | - Chengxin Pei
- State key Laboratory of NBC Protection for Civilian, Beijing 102205, China
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4
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van der Velden WJC, Smit FX, Christiansen CB, Møller TC, Hjortø GM, Larsen O, Schiellerup SP, Bräuner-Osborne H, Holst JJ, Hartmann B, Frimurer TM, Rosenkilde MM. GLP-1 Val8: A Biased GLP-1R Agonist with Altered Binding Kinetics and Impaired Release of Pancreatic Hormones in Rats. ACS Pharmacol Transl Sci 2021; 4:296-313. [PMID: 33615180 DOI: 10.1021/acsptsci.0c00193] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/12/2020] [Indexed: 02/08/2023]
Abstract
Biased ligands that selectively confer activity in one pathway over another are pharmacologically important because biased signaling may reduce on-target side effects and improve drug efficacy. Here, we describe an N-terminal modification in the incretin hormone glucagon-like peptide (GLP-1) that alters the signaling capabilities of the GLP-1 receptor (GLP-1R) by making it G protein biased over internalization but was originally designed to confer DPP-4 resistance and thereby prolong the half-life of GLP-1. Despite similar binding affinity, cAMP production, and calcium mobilization, substitution of a single amino acid (Ala8 to Val8) in the N-terminus of GLP-1(7-36)NH2 (GLP-1 Val8) severely impaired its ability to internalize GLP-1R compared to endogenous GLP-1. In-depth binding kinetics analyses revealed shorter residence time for GLP-1 Val8 as well as a slower observed association rate. Molecular dynamics (MD) displayed weaker and less interactions of GLP-1 Val8 with GLP-1R, as well as distinct conformational changes in the receptor compared to GLP-1. In vitro validation of the MD, by receptor alanine substitutions, confirmed stronger impairments of GLP-1 Val8-mediated signaling compared to GLP-1. In a perfused rat pancreas, acute stimulation with GLP-1 Val8 resulted in a lower insulin and somatostatin secretion compared to GLP-1. Our study illustrates that profound differences in molecular pharmacological properties, which are essential for the therapeutic targeting of the GLP-1 system, can be induced by subtle changes in the N-terminus of GLP-1. This information could facilitate the development of optimized GLP-1R agonists.
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Affiliation(s)
- Wijnand J C van der Velden
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Florent X Smit
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Charlotte B Christiansen
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences University of Copenhagen, Copenhagen 2200, Denmark
| | - Thor C Møller
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Gertrud M Hjortø
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Olav Larsen
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Sine P Schiellerup
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Hans Bräuner-Osborne
- Department of Drug Design and Pharmacology, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2100, Denmark
| | - Jens J Holst
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences University of Copenhagen, Copenhagen 2200, Denmark
| | - Bolette Hartmann
- Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark.,Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences University of Copenhagen, Copenhagen 2200, Denmark
| | - Thomas M Frimurer
- Section for Metabolic Receptology, Novo Nordisk Foundation Center for Basic Metabolic Research, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Mette M Rosenkilde
- Laboratory for Molecular Pharmacology, Department of Biomedical Sciences, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
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5
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Bird GH, Fu A, Escudero S, Godes M, Opoku-Nsiah K, Wales TE, Cameron MD, Engen JR, Danial NN, Walensky LD. Hydrocarbon-Stitched Peptide Agonists of Glucagon-Like Peptide-1 Receptor. ACS Chem Biol 2020; 15:1340-1348. [PMID: 32348108 DOI: 10.1021/acschembio.0c00308] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022]
Abstract
Glucagon-like peptide 1 (GLP-1) is a natural peptide agonist of the GLP-1 receptor (GLP-1R) found on pancreatic β-cells. Engagement of the receptor stimulates insulin release in a glucose-dependent fashion and increases β-cell mass, two ideal features for pharmacologic management of type 2 diabetes. Thus, intensive efforts have focused on developing GLP-1-based peptide agonists of GLP-1R for therapeutic application. A primary challenge has been the naturally short half-life of GLP-1 due to its rapid proteolytic degradation in vivo. Whereas mutagenesis and lipidation strategies have yielded clinical agents, we developed an alternative approach to preserving the structure and function of GLP-1 by all-hydrocarbon i, i + 7 stitching. This particular "stitch" is especially well-suited for reinforcing and protecting the structural fidelity of GLP-1. Lead constructs demonstrate striking proteolytic stability and potent biological activity in vivo. Thus, we report a facile approach to generating alternative GLP-1R agonists for glycemic control.
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Affiliation(s)
- Gregory H. Bird
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, Massachusetts 02215, United States
- Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, Massachusetts 02215, United States
| | - Accalia Fu
- Department of Cancer Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston Massachusetts 02215, United States
- Department of Cell Biology, Harvard Medical School, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, United States
| | - Silvia Escudero
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, Massachusetts 02215, United States
- Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, Massachusetts 02215, United States
| | - Marina Godes
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, Massachusetts 02215, United States
- Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, Massachusetts 02215, United States
| | - Kwadwo Opoku-Nsiah
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, Massachusetts 02215, United States
- Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, Massachusetts 02215, United States
| | - Thomas E. Wales
- Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Michael D. Cameron
- DMPK Core, Department of Molecular Medicine, The Scripps Research Institute, 130 Scripps Way, Jupiter, Florida 33458, United States
| | - John R. Engen
- Department of Chemistry and Chemical Biology, Northeastern University, 360 Huntington Avenue, Boston, Massachusetts 02115, United States
| | - Nika N. Danial
- Department of Cancer Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston Massachusetts 02215, United States
- Department of Medical Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, Massachusetts 02215, United States
- Department of Medicine, Harvard Medical School, 240 Longwood Avenue, Boston, Massachusetts 02115, United States
| | - Loren D. Walensky
- Department of Pediatric Oncology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, Massachusetts 02215, United States
- Linde Program in Cancer Chemical Biology, Dana-Farber Cancer Institute, 450 Brookline Avenue, Boston, Massachusetts 02215, United States
- Department of Pediatrics, Harvard Medical School, Boston, Massachusetts 02115, United States
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6
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O'Harte FPM, Parthsarathy V, Flatt PR. Chronic apelin analogue administration is more effective than established incretin therapies for alleviating metabolic dysfunction in diabetic db/db mice. Mol Cell Endocrinol 2020; 504:110695. [PMID: 31904406 DOI: 10.1016/j.mce.2019.110695] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2019] [Revised: 11/26/2019] [Accepted: 12/27/2019] [Indexed: 01/24/2023]
Abstract
Stable apelin-13 peptide analogues have shown promising acute antidiabetic effects in mice with diet-induced obesity diabetes. Here the efficacy of (pGlu)apelin-13 amide (apelin amide) and the acylated analogue (pGlu)(Lys8GluPAL)apelin-13 amide (apelin FA), were examined following chronic administration in db/db mice, a genetic model of degenerative diabetes. Groups of 9-week old male db/db mice (n = 8) received twice daily injections (09:00 and 17:00 h; i.p.) or saline vehicle, apelin amide, apelin FA, or the established incretin therapies, exendin-4(1-39) or liraglutide, all at 25 nmol/kg body weight for 21 days. Control C57BL/6J mice were given saline twice daily. No changes in body weight or food intake were observed with either apelin or liraglutide treatments, but exendin-4 showed a reduction in cumulative food intake (p < 0.01) compared with saline-treated db/db mice. Apelin analogues and incretin mimetics induced sustained improvements of glycaemia (p < 0.05 to p < 0.001, from day 9-21), lowered HbA1c at 21 days (p < 0.05) and raised plasma insulin concentrations. The treatments also improved OGTT and ipGTT with enhanced insulin responses compared with saline-treated control db/db mice (p < 0.05 to p < 0.001). Apelin amide was superior to incretin mimetics in lowering plasma triglycerides by 34% (p < 0.05). Apelin analogues unlike both incretin mimetics reduced pancreatic α-cell area (p < 0.05 to p < 0.01) and all peptide treatments enhanced pancreatic insulin content (p < 0.05 to p < 0.01). In conclusion, longer-term administration of apelin-13 analogues, induced similar and in some respects more effective metabolic improvements than incretin mimetics in db/db mice, providing a viable alternative approach for counteracting metabolic dysfunction for mild and more degenerative forms of the disease.
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Affiliation(s)
- Finbarr P M O'Harte
- The SAAD Centre for Pharmacy & Diabetes, University of Ulster, Coleraine, Northern Ireland, BT52 1SA, UK.
| | - Vadivel Parthsarathy
- The SAAD Centre for Pharmacy & Diabetes, University of Ulster, Coleraine, Northern Ireland, BT52 1SA, UK.
| | - Peter R Flatt
- The SAAD Centre for Pharmacy & Diabetes, University of Ulster, Coleraine, Northern Ireland, BT52 1SA, UK
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7
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Wang M, Yao P, Gao M, Jin J, Yu Y. Novel fatty chain-modified GLP-1R G-protein biased agonist exerts prolonged anti-diabetic effects through targeting receptor binding sites. RSC Adv 2020; 10:8044-8053. [PMID: 35497855 PMCID: PMC9049875 DOI: 10.1039/c9ra10593j] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2019] [Accepted: 12/30/2019] [Indexed: 02/05/2023] Open
Abstract
Here, we design and evaluate novel long-lasting GLP-1R G-protein-biased agonists with promising pharmacological virtues. Firstly, six GLP-1R G-protein-biased peptides (named PX01-PX06), screened by using a previous reported high-throughput autocrine-based method, were fused to the N-terminus of GLP-1(9-37) to generate six fusion peptides (PX07-PX012). In vitro surface plasmon resonance (SPR) measurements showed that PX09 exerts the highest binding affinity for both human and mouse GLP-1R extracellular domains (ECD). We further used the PX09 as a starting point to conduct site-specific modifications yielding twelve lysine-modified conjugates, termed PX13-PX24. Of these conjugates, PX17 retained relatively better in vitro GLP-1R activation potency and plasma stability compared with other ones. Preclinical studies in db/db mice demonstrated that acute treatment of PX17 exerts enhanced hypoglycemic and insulinotropic activities in a dosage dependent model within the range of 0.1-0.9 mg kg-1. Similarly, prolonged glucose-lowering abilities were exhibited in modified multiple oral glucose tolerance tests (OGTTs) and a hypoglycemic duration test. Apparently prolonged in vivo half-lives of ∼96 and ∼141 h were observed after a single subcutaneous administration of PX17 at 0.1 and 0.3 mg kg-1, respectively, in healthy cynomolgus monkeys. In addition, twice-weekly treatment of PX17 in db/db mice for 8 weeks obviously improved the hemoglobin A1C (HbA1C), and was more effective at improving the insulin resistance, glucose tolerance as well as function of pancreatic beta cells compared with Semaglutide. Furthermore, subcutaneously dosed PX17 in diet induced obese (DIO) mice achieved long-term beneficial effects on food intake and body weight control, HbA1C and inflammation-related factor level lowering. The above results indicate that PX17, as a novel GLP-1R G-protein-biased agonist, may be a promising candidate for antidiabetic therapies.
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Affiliation(s)
- Maorong Wang
- Department of Endocrinology, West China Hospital, Sichuan University Chengdu Sichuan China 610041
- Department of Endocrinology, Affiliated Hospital of Hubei University for Nationalities Enshi 445000 Hubei China
| | - Ping Yao
- Department of Endocrinology, Affiliated Hospital of Hubei University for Nationalities Enshi 445000 Hubei China
| | - Minpeng Gao
- China Pharmaceutical University Nanjing Jiangsu 210009 P. R. China
| | - Jian Jin
- Jiangnan University Wuxi Jiangsu 214062 P. R. China
| | - Yerong Yu
- Department of Endocrinology, West China Hospital, Sichuan University Chengdu Sichuan China 610041
- Jiangnan University Wuxi Jiangsu 214062 P. R. China
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8
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Lafferty RA, Gault VA, Flatt PR, Irwin N. Effects of 2 Novel PYY(1-36) Analogues, (P 3L 31P 34)PYY(1-36) and PYY(1-36)(Lys 12PAL), on Pancreatic Beta-Cell Function, Growth, and Survival. CLINICAL MEDICINE INSIGHTS-ENDOCRINOLOGY AND DIABETES 2019; 12:1179551419855626. [PMID: 31244528 PMCID: PMC6580715 DOI: 10.1177/1179551419855626] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/10/2019] [Accepted: 05/15/2019] [Indexed: 12/14/2022]
Abstract
Recent studies have identified a beneficial role for peptide tyrosine tyrosine
(PYY) on pancreatic beta-cell function and survival. These effects are linked to
the activation of neuropeptide Y1 receptors (NPYR1s) by PYY(1-36). However,
PYY(1-36) is subject to rapid degradation by dipeptidyl peptidase-4 (DPP-4),
resulting is the loss of NPYR1 activity. Therefore, the aim of this study was to
develop 2 enzymatically stable PYY(1-36) analogues, namely,
(P3L31P34)PYY(1-36) and
PYY(1-36)(Lys12PAL), with further structural modifications to
enhance NPYR1 specificity. As expected,
(P3L31P34)PYY(1-36) was fully resistant to
DPP-4-mediated degradation in vitro, whereas PYY(1-36) and
PYY(1-36)(Lys12PAL) were both liable to DPP-4 breakdown.
PYY(1-36) and (P3L31P34)PYY(1-36) induced
significant reductions in glucose-stimulated insulin secretion (GSIS) from BRIN
BD11 cells, but only PYY(1-36) diminished alanine-stimulated insulin secretion.
In contrast, PYY(1-36)(Lys12PAL) had no impact on GSIS or
alanine-induced insulin release. All 3 PYY peptides significantly enhanced
proliferation in BRIN BD11 and 1.1B4 beta-cell lines, albeit only at the highest
concentration examined, 10-6 M, for
(P3L31P34)PYY(1-36) and
PYY(1-36)(Lys12PAL) in BRIN BD11 cells. Regarding the protection
of beta-cells against cytokine-induced apoptosis, PYY(1-36) induced clear
protective effects. Both (P3L31P34)PYY(1-36)
and PYY(1-36)(Lys12PAL) offered some protection against apoptosis in
BRIN BD11 cells, but were significantly less efficacious than PYY(1-36).
Similarly, in 1.1B4 cells, both PYY analogues (10-6 M) protected
against cytokine-induced apoptosis, but
(P3L31P34)PYY(1-36) was significantly less
effective than PYY(1-36). All 3 PYY peptides had no impact on refeeding in
overnight fasted mice. These data underline the beta-cell benefits of PYY(1-36)
and highlight the challenges of synthesising stable, bioactive, NPYR1-specific,
PYY(1-36) analogues.
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Affiliation(s)
- Ryan A Lafferty
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK.,Diabetes Research Group, University of Ulster, Coleraine, UK
| | - Victor A Gault
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK
| | - Peter R Flatt
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK
| | - Nigel Irwin
- SAAD Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK
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9
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Alavi SE, Cabot PJ, Moyle PM. Glucagon-Like Peptide-1 Receptor Agonists and Strategies To Improve Their Efficiency. Mol Pharm 2019; 16:2278-2295. [PMID: 31050435 DOI: 10.1021/acs.molpharmaceut.9b00308] [Citation(s) in RCA: 42] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
Abstract
Type 2 diabetes mellitus (T2DM) is increasing in global prevalence and is associated with serious health problems (e.g., cardiovascular disease). Various treatment options are available for T2DM, including the incretin hormone glucagon-like peptide-1 (GLP-1). GLP-1 is a therapeutic peptide secreted from the intestines following food intake, which stimulates the secretion of insulin from the pancreas. The native GLP-1 has a very short plasma half-life, owning to renal clearance and degradation by the enzyme dipeptidyl peptidase-4. To overcome this issue, various GLP-1 agonists with increased resistance to proteolytic degradation and reduced renal clearance have been developed, with several currently marketed. Strategies, such as controlled release delivery systems, methods to reduce renal clearance (e.g., PEGylation and conjugation to antibodies), and methods to improve proteolytic stability (e.g., stapling, cyclization, and glycosylation) provide means to further improve the ability of GLP-1 analogs. These will be discussed in this literature review.
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Affiliation(s)
- Seyed Ebrahim Alavi
- School of Pharmacy , The University of Queensland , Woolloongabba , 4102 , Australia
| | - Peter J Cabot
- School of Pharmacy , The University of Queensland , Woolloongabba , 4102 , Australia
| | - Peter M Moyle
- School of Pharmacy , The University of Queensland , Woolloongabba , 4102 , Australia
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10
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Ding L, Lu S, Wang Y, Chen H, Long W, Ma C, He E, Yan D, Tan F. BPI-3016, a novel long-acting hGLP-1 analogue for the treatment of Type 2 diabetes mellitus. Pharmacol Res 2017; 122:130-139. [PMID: 28619366 DOI: 10.1016/j.phrs.2017.05.007] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/23/2017] [Revised: 05/10/2017] [Accepted: 05/11/2017] [Indexed: 11/29/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) analogues have been commonly used as add-on medications for patients with Type 2 diabetes mellitus (T2DM). Currently, the development of long-acting GLP-1 analogues which allow the freedom and flexibility of once-weekly injections while maintaining their potency for a relatively long period has become the mainstream. Here, we successfully developed a long-acting human GLP-1(7-37) analogue (BPI-3016) with significantly extended half-life and increased resistance to dipeptidyl peptidase IV (DPP-IV) cleavage by structural modifications of human GLP-1. In vitro activity of BPI-3016 including GLP-1 receptor affinity and stimulation of cyclic adenosine monophosphate (cAMP) production was measured. In vivo activity of BPI-3016 such as its effects on glycemic control, β-cell mass and body weight was evaluated in ob/ob mice, db/db mice, and spontaneous diabetic cynomolgus monkeys. The results indicated that BPI-3016 preserved receptor affinity to GLP receptors, and was capable of stimulating cAMP production. In in vivo pharmacokinetic study, the half-life of BPI-3016 was more than 95h after single dosing in diabetic cynomolgus monkeys. Also, BPI-3016 reduced fasting and post-prandial plasma glucose levels for up to a week after a single dose; It reduced body mass index (BMI), body fat, improved glucose tolerance and showed insulinotropic effects after once-weekly injection for 7 weeks. In conclusion, BPI-3016 retains the effects of GLP-1 with significantly prolonged half-life, making it a promising therapy for type 2 diabetes with once-weekly treatment in the clinic.
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Affiliation(s)
- Lieming Ding
- Department of Preclinical Research, Betta Pharmaceuticals Co., Ltd, Beijing, China
| | - Sisi Lu
- Department of Preclinical Research, Betta Pharmaceuticals Co., Ltd, Beijing, China
| | - Yanping Wang
- Department of Preclinical Research, Beijing Jacobio Pharma Co., Ltd, Beijing, China
| | - Haibo Chen
- Department of Preclinical Research, Betta Pharmaceuticals Co., Ltd, Beijing, China
| | - Wei Long
- Department of Immunology, Peking University School of Basic Medical Science, Beijing, China
| | - Cunbo Ma
- Department of Preclinical Research, Beijing Jacobio Pharma Co., Ltd, Beijing, China
| | - Erlong He
- Department of Preclinical Research, Betta Pharmaceuticals Co., Ltd, Beijing, China
| | - Dan Yan
- Department of Preclinical Research, Betta Pharmaceuticals Co., Ltd, Beijing, China
| | - Fenlai Tan
- Department of Preclinical Research, Betta Pharmaceuticals Co., Ltd, Beijing, China.
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11
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O'Harte FPM, Ng MT, Lynch AM, Conlon JM, Flatt PR. Dogfish glucagon analogues counter hyperglycaemia and enhance both insulin secretion and action in diet-induced obese diabetic mice. Diabetes Obes Metab 2016; 18:1013-24. [PMID: 27357054 DOI: 10.1111/dom.12713] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2016] [Revised: 06/16/2016] [Accepted: 06/23/2016] [Indexed: 12/11/2022]
Abstract
AIMS To investigate the antidiabetic actions of three dogfish glucagon peptide analogues [known glucagon-like peptide-1 and glucagon receptor co-agonists] after chronic administration in diet-induced high-fat-diet-fed diabetic mice. MATERIALS AND METHODS National Institutes of Health Swiss mice were pre-conditioned to a high-fat diet (45% fat) for 100 days, and control mice were fed a normal diet (10% fat). Normal diet control and high-fat-fed control mice received twice-daily intraperitoneal (i.p.) saline injections, while the high-fat-fed treatment groups (n = 8) received twice-daily injections of exendin-4(1-39), [S2a]dogfish glucagon, [S2a]dogfish glucagon exendin-4(31-39) or [S2a]dogfish glucagon-Lys(30) -γ-glutamyl-PAL (25 nmol/kg body weight) for 51 days. RESULTS After dogfish glucagon analogue treatment, there was a rapid and sustained decrease in non-fasting blood glucose and an associated insulinotropic effect (analysis of variance, p < .05 to <.001) compared with saline-treated high-fat-fed controls. All peptide treatments significantly improved i.p. and oral glucose tolerance with concomitant increased insulin secretion compared with saline-treated high-fat-fed controls (p <.05 to <.001). After chronic treatment, no receptor desensitization was observed but insulin sensitivity was enhanced for all peptide-treated groups (p < .01 to <.001) except [S2a]dogfish glucagon. Both exendin-4 and [S2a]dogfish glucagon exendin-4(31-39) significantly reduced plasma triglyceride concentrations compared with those found in lean controls (p = .0105 and p = .0048, respectively). Pancreatic insulin content was not affected by peptide treatments but [S2a]dogfish glucagon and [S2a]dogfish glucagon exendin-4(31-39) decreased pancreatic glucagon by 28%-34% (p = .0221 and p = .0075, respectively). The percentage of β-cell area within islets was increased by exendin-4 and peptide analogue treatment groups compared with high-fat-fed controls and the β-cell area decreased (p < .05 to <.01). CONCLUSIONS Overall, dogfish glucagon co-agonist analogues had several beneficial metabolic effects, showing therapeutic potential for type 2 diabetes.
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Affiliation(s)
- F P M O'Harte
- School of Biomedical Sciences, Saad Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK.
| | - M T Ng
- School of Biomedical Sciences, Saad Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK
| | - A M Lynch
- School of Biomedical Sciences, Saad Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK
| | - J M Conlon
- School of Biomedical Sciences, Saad Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK
| | - P R Flatt
- School of Biomedical Sciences, Saad Centre for Pharmacy and Diabetes, University of Ulster, Coleraine, UK
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12
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O'Harte FPM, Ng MT, Lynch AM, Conlon JM, Flatt PR. Novel dual agonist peptide analogues derived from dogfish glucagon show promising in vitro insulin releasing actions and antihyperglycaemic activity in mice. Mol Cell Endocrinol 2016; 431:133-44. [PMID: 27179756 DOI: 10.1016/j.mce.2016.05.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/17/2016] [Revised: 05/10/2016] [Accepted: 05/10/2016] [Indexed: 02/07/2023]
Abstract
The antidiabetic potential of thirteen novel dogfish glucagon derived analogues were assessed in vitro and in acute in vivo studies. Stable peptide analogues enhanced insulin secretion from BRIN-BD11 β-cells (p < 0.001) and reduced acute glycaemic responses following intraperitoneal glucose (25 nmol/kg) in healthy NIH Swiss mice (p < 0.05-p<0.001). The in vitro insulinotropic actions of [S2a]dogfish glucagon, [S2a]dogfish glucagon-exendin-4(31-39) and [S2a]dogfish glucagon-Lys(30)-γ-glutamyl-PAL, were blocked (p < 0.05-p<0.001) by the specific GLP-1 and glucagon receptor antagonists, exendin-4(9-39) and (desHis(1)Pro(4)Glu(9))glucagon amide but not by (Pro(3))GIP, indicating lack of GIP receptor involvement. These analogues dose-dependently stimulated cAMP production in GLP-1 and glucagon (p < 0.05-p<0.001) but not GIP-receptor transfected cells. They improved acute glycaemic and insulinotropic responses in high-fat fed diabetic mice and in wild-type C57BL/6J and GIPR-KO mice (p < 0.05-p<0.001), but not GLP-1R-KO mice, confirming action on GLP-1 but not GIP receptors. Overall, dogfish glucagon analogues have potential for diabetes therapy, exerting beneficial metabolic effects via GLP-1 and glucagon receptors.
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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, Co. Derry, BT52 1SA, Northern Ireland, UK.
| | - M T Ng
- The Saad Centre for Pharmacy & Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Co. Derry, BT52 1SA, Northern Ireland, UK
| | - A M Lynch
- The Saad Centre for Pharmacy & Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Co. Derry, BT52 1SA, Northern Ireland, UK
| | - J M Conlon
- The Saad Centre for Pharmacy & Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Co. Derry, BT52 1SA, Northern Ireland, UK
| | - P R Flatt
- The Saad Centre for Pharmacy & Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine, Co. Derry, BT52 1SA, Northern Ireland, UK
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13
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Zhou XR, Zhang Q, Tian XB, Cao YM, Liu ZQ, Fan R, Ding XF, Zhu Z, Chen L, Luo SZ. From a pro-apoptotic peptide to a lytic peptide: One single residue mutation. BIOCHIMICA ET BIOPHYSICA ACTA-BIOMEMBRANES 2016; 1858:1914-25. [DOI: 10.1016/j.bbamem.2016.05.012] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/16/2015] [Revised: 05/12/2016] [Accepted: 05/16/2016] [Indexed: 12/14/2022]
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14
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A new GLP-1 analogue with prolonged glucose-lowering activity in vivo via backbone-based modification at the N-terminus. Bioorg Med Chem 2016; 24:1163-70. [PMID: 26895657 DOI: 10.1016/j.bmc.2016.01.036] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2015] [Accepted: 01/18/2016] [Indexed: 12/25/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) is an endogenous insulinotropic hormone with wonderful glucose-lowering activity. However, its clinical use in type II diabetes is limited due to its rapid degradation at the N-terminus by dipeptidyl peptidase IV (DPP-IV). Among the N-terminal modifications of GLP-1, backbone-based modification was rarely reported. Herein, we employed two backbone-based strategies to modify the N-terminus of tGLP-1. Firstly, the amide N-methylated analogues 2-6 were designed and synthesized to make a full screening of the N-terminal amide bonds, and the loss of GLP-1 receptor (GLP-1R) activation indicated the importance of amide H-bonds. Secondly, with retaining the N-terminal amide H-bonds, the β-peptide replacement strategy was used and analogues 7-13 were synthesized. By two rounds of screening, analogue 10 was identified. Analogue 10 greatly improved the DPP-IV resistance with maintaining good GLP-1R activation in vitro, and showed approximately a 4-fold prolonged blood glucose-lowering activity in vivo in comparison with tGLP-1. This modification strategy will benefit the development of GLP-1-based anti-diabetic drugs.
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15
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Tian X, Sun F, Zhou XR, Luo SZ, Chen L. Role of peptide self-assembly in antimicrobial peptides. J Pept Sci 2015; 21:530-9. [DOI: 10.1002/psc.2788] [Citation(s) in RCA: 74] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Revised: 05/05/2015] [Accepted: 05/05/2015] [Indexed: 12/31/2022]
Affiliation(s)
- Xibo Tian
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology; Beijing University of Chemical Technology; Beijing 100029 China
| | - Fude Sun
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology; Beijing University of Chemical Technology; Beijing 100029 China
| | - Xi-Rui Zhou
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology; Beijing University of Chemical Technology; Beijing 100029 China
| | - Shi-Zhong Luo
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology; Beijing University of Chemical Technology; Beijing 100029 China
| | - Long Chen
- Beijing Key Laboratory of Bioprocess, College of Life Science and Technology; Beijing University of Chemical Technology; Beijing 100029 China
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16
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Manandhar B, Ahn JM. Glucagon-like peptide-1 (GLP-1) analogs: recent advances, new possibilities, and therapeutic implications. J Med Chem 2014; 58:1020-37. [PMID: 25349901 PMCID: PMC4329993 DOI: 10.1021/jm500810s] [Citation(s) in RCA: 108] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
![]()
Glucagon-like peptide-1 (GLP-1) is
an incretin that plays important
physiological roles in glucose homeostasis. Produced from intestine
upon food intake, it stimulates insulin secretion and keeps pancreatic
β-cells healthy and proliferating. Because of these beneficial
effects, it has attracted a great deal of attention in the past decade,
and an entirely new line of diabetic therapeutics has emerged based
on the peptide. In addition to the therapeutic applications, GLP-1
analogs have demonstrated a potential in molecular imaging of pancreatic β-cells;
this may be useful in early detection of the disease and evaluation
of therapeutic interventions, including islet transplantation. In
this Perspective, we focus on GLP-1 analogs for their studies on improvement
of biological activities, enhancement of metabolic stability, investigation
of receptor interaction, and visualization of the pancreatic islets.
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Affiliation(s)
- Bikash Manandhar
- Department of Chemistry, University of Texas at Dallas , Richardson, Texas 75080, United States
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17
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Abstract
Peptides have some unique and superior features compared to proteins. However, the use of peptides as therapeutics is hampered by their low stability and cell selectivity. In this study, a new lytic peptide (CL-1, FLGALFRALSRLL) was constructed. Under the physiological condition, peptide CL-1 self-assembled into dynamically stable aggregates with fibrils-like structures. Aggregated CL-1 demonstrated dramatically altered activity and stability in comparison with single molecule CL-1 and other lytic peptides: when incubated with cocultured bacteria and tissue cells, CL-1 aggregates killed bacteria selectively but spared cocultured human cells; CL-1 aggregates were kept intact in human serum for more than five hours. Peptide-cell interaction studies performed on lipid monolayers and live human tissue cells revealed that in comparison with monomeric CL-1, aggregated CL-1 had decreased cell affinity and membrane insertion capability on tissue cells. A dynamic process involving aggregate dissociation and rearrangement seemed to be an essential step for membrane bound CL-1 aggregates to realize its cytotoxicity to tissue cells. Our study suggests that peptide aggregation could be as important as the charge and secondary structure of a peptide in affecting peptide-cell interactions. Controlling peptide self-assembly represents a new way to increase the stability and cell selectivity of bioactive peptides for wide biomedical applications.
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Affiliation(s)
- Long Chen
- Department of Chemistry, Chemical Biology, and Biomedical Engineering, Charles V. Schaefer School of Engineering and Sciences, Stevens Institute of Technology, Hoboken, NJ 07030, USA
| | - Jun F. Liang
- Department of Chemistry, Chemical Biology, and Biomedical Engineering, Charles V. Schaefer School of Engineering and Sciences, Stevens Institute of Technology, Hoboken, NJ 07030, USA
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18
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Lennox R, Porter DW, Flatt PR, Gault VA. (Val8)GLP-1-Glu-PAL: a GLP-1 Agonist That Improves Hippocampal Neurogenesis, Glucose Homeostasis, and β-Cell Function in High-Fat-Fed Mice. ChemMedChem 2012; 8:595-602. [DOI: 10.1002/cmdc.201200409] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2012] [Revised: 10/17/2012] [Indexed: 11/10/2022]
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19
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Chen L, Tu Z, Voloshchuk N, Liang JF. Lytic peptides with improved stability and selectivity designed for cancer treatment. J Pharm Sci 2012; 101:1508-17. [PMID: 22227945 DOI: 10.1002/jps.23043] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2011] [Revised: 11/22/2011] [Accepted: 12/14/2011] [Indexed: 11/10/2022]
Abstract
Lytic peptides are a group of membrane-acting peptides, which have excellent activity to drug-resistant cells. In this study, the stability and tumor selectivity of newly designed pH-activated lytic peptides were studied. We found that despite varied secondary structures, pH-induced structure changes could not be directly linked to the activity and pH sensitivity of peptides. On the contrary, formation of aggregates had great impacts on peptide binding and insertion into the lipid bilayer of cell membrane. It was found that the pH controlled peptide aggregation and dissolution was responsible for the pH-dependent membrane lysis activity of peptides. One peptide (PTP-7c) formed stable amyloid fibrils, which did not completely dissolve under acidic conditions. As a result, PTP-7c had the lowest membrane lysis and cell killing activities among tested lytic peptides. As solid tumors have consistently low extracellular pHs, peptides with acid-activation features showed improved selectivity to cancer cells. In addition, self-assembled lytic peptides were found to become more stable and showed dramatically increased half lives (up to 11 h) in human plasma. These new lytic peptides with good stability and acid-activated cell lysis activity will have wide biomedical applications especially for the treatment of cancers in which drug resistance has developed.
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Affiliation(s)
- Long Chen
- Department of Chemistry, Chemical Biology, and Biomedical Engineering, Stevens Institute of Technology, Hoboken, New Jersey 07030, USA
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20
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Agnew A, Calderwood D, Chevallier OP, Greer B, Grieve DJ, Green BD. Chronic treatment with a stable obestatin analog significantly alters plasma triglyceride levels but fails to influence food intake; fluid intake; body weight; or body composition in rats. Peptides 2011; 32:755-62. [PMID: 21167891 DOI: 10.1016/j.peptides.2010.12.005] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/27/2010] [Revised: 12/02/2010] [Accepted: 12/02/2010] [Indexed: 01/21/2023]
Abstract
Obestatin (OB(1-23) is a 23 amino acid peptide encoded on the preproghrelin gene, originally reported to have metabolic actions related to food intake, gastric emptying and body weight. The biological instability of OB(1-23) has recently been highlighted by studies demonstrating its rapid enzymatic cleavage in a number of biological matrices. We assessed the stability of both OB(1-23) and an N-terminally PEGylated analog (PEG-OB(1-23)) before conducting chronic in vivo studies. Peptides were incubated in rat liver homogenate and degradation monitored by LC-MS. PEG-OB(1-23) was approximately 3-times more stable than OB(1-23). Following a 14 day infusion of Sprague-Dawley rats with 50 nmol/kg/day of OB(1-23) or a N-terminally PEGylated analog (PEG-OB(1-23)), we found no changes in food/fluid intake, body weight and plasma glucose or cholesterol between groups. Furthermore, morphometric liver, muscle and white adipose tissue (WAT) weights and tissue triglyceride concentrations remained unaltered between groups. However, with stabilized PEG-OB(1-23) we observed a 40% reduction in plasma triglycerides. These findings indicate that PEG-OB(1-23) is an OB(1-23) analog with significantly enhanced stability and suggest that obestatin could play a role in modulating physiological lipid metabolism, although it does not appear to be involved in regulation of food/fluid intake, body weight or fat deposition.
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Affiliation(s)
- A Agnew
- School of Biological Sciences, Queens University Belfast, David Keir Building, Stranmillis Road, Belfast BT9 5AG, UK
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21
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Kerr BD, Flatt PR, Gault VA. (d-Ser2)Oxm[mPEG-PAL]: A novel chemically modified analogue of oxyntomodulin with antihyperglycaemic, insulinotropic and anorexigenic actions. Biochem Pharmacol 2010; 80:1727-35. [DOI: 10.1016/j.bcp.2010.08.010] [Citation(s) in RCA: 44] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2010] [Revised: 08/09/2010] [Accepted: 08/12/2010] [Indexed: 01/12/2023]
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22
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Druce MR, Minnion JS, Field BCT, Patel SR, Shillito JC, Tilby M, Beale KEL, Murphy KG, Ghatei MA, Bloom SR. Investigation of structure-activity relationships of Oxyntomodulin (Oxm) using Oxm analogs. Endocrinology 2009; 150:1712-22. [PMID: 19074579 DOI: 10.1210/en.2008-0828] [Citation(s) in RCA: 74] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Oxyntomodulin (Oxm) is an intestinal peptide that inhibits food intake and body weight in rodents and humans. These studies used peptide analogs to study aspects of structure and function of Oxm, and the sensitivity of parts of the Oxm sequence to degradation. Analogs of Oxm were synthesized and studied using receptor binding and degradation studies in vitro. Their effects on food intake and conditioned taste avoidance were measured in vivo in rodents. Oxm breakdown by the enzyme dipeptidyl peptidase IV (DPPIV) was demonstrated in vitro and in vivo. In vitro degradation was reduced and in vivo bioactivity increased by inhibitors of DPPIV. Modifications to the N terminus of Oxm modulated binding to the glucagon-like peptide (GLP)-1 receptor and degradation by DPPIV. Modifications to the midsection of Oxm modulated binding to the GLP-1 receptor and degradation by neutral endopeptidase. These modifications also altered bioactivity in vivo. The C-terminal octapeptide of Oxm was shown to contribute to the properties of Oxm in vitro and in vivo but was not alone sufficient for the effects of the peptide. Elongation and acylation of the C terminus of Oxm altered GLP-1 receptor binding and duration of action in vivo, which may be due to changes in peptide clearance. An Oxm analog was developed with enhanced pharmaceutical characteristics, with greater potency and longevity with respect to effects on food intake. These studies suggest that Oxm is a potential target for antiobesity drug design.
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Affiliation(s)
- Maralyn R Druce
- Department of Investigative Medicine, Imperial College London, London, United Kingdom.
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23
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Tu Z, Hao J, Kharidia R, Meng XG, Liang JF. Improved stability and selectivity of lytic peptides through self-assembly. Biochem Biophys Res Commun 2007; 361:712-7. [PMID: 17678628 DOI: 10.1016/j.bbrc.2007.06.178] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/20/2007] [Accepted: 06/21/2007] [Indexed: 12/12/2022]
Abstract
Widespread clinical applications of peptide drugs have been hindered by their low stability and selectivity. Peptides can be easily digested by various enzymes in the blood and thus show a short life-span. Meanwhile, peptide drugs can cause severe normal tissue damage due to their low selectivity. Therefore, for effective therapy, a high dosage of peptide is required which is usually in excess of the clinically and economically acceptable level. In this study, we have tried to design new lytic peptides which can self-assemble into peptide fibrils with defined nanostructures as observed under atomic force microscopy. Lytic peptides in self-assembled peptide fibrils will lose their cell lysis activity but become resistant to enzyme degradation. Such lytic peptide self-assembly has proven to be a reversible process which is controlled by surrounded environments. A concentration controlled sustained release of free and active lytic peptide from self-assembled peptide fibrils has been achieved. Self-assembled lytic peptides with enzyme resistance, sustained release, and prodrug feature may have great clinical application potentials.
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Affiliation(s)
- Zhigang Tu
- Department of Chemistry and Chemical Biology, Stevens Institute of Technology, Castle Point on Hudson, Hoboken, NJ 07030, USA
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24
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Gault VA, Hunter K, Irwin N, Greer B, Green BD, Harriott P, O'Harte FPM, Flatt PR. Characterisation and glucoregulatory actions of a novel acylated form of the (Pro3)GIP receptor antagonist in type 2 diabetes. Biol Chem 2007; 388:173-9. [PMID: 17261080 DOI: 10.1515/bc.2007.019] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
In this study, we tested the biological activity of a novel acylated form of (Pro3)glucose-dependent insulinotropic polypetide [(Pro3)GIP] prepared by conjugating palmitic acid to Lys16 to enhance its efficacy in vivo by promoting binding to albumin and extending its biological actions. Like the parent molecule (Pro3)GIP, (Pro3)GIPLys16PAL was completely stable to the actions of DPP-IV and significantly (p<0.01 to p<0.001) inhibited GIP-stimulated cAMP production and cellular insulin secretion. Furthermore, acute administration of (Pro3)GIPLys16PAL also significantly (p<0.05 to p<0.001) countered the glucose-lowering and insulin-releasing actions of GIP in ob/ob mice. Daily injection of (Pro3)GIPLys16PAL (25 nmol/kg bw) in 14-18-week-old ob/ob mice over 14 days had no effect on body weight, food intake or non-fasting plasma glucose and insulin concentrations. (Pro3)GIPLys16PAL treatment also failed to significantly alter the glycaemic response to an i.p. glucose load or test meal, but insulin concentrations were significantly reduced (1.5-fold; p<0.05) after the glucose load. Insulin sensitivity was enhanced (1.3-fold; p<0.05) and pancreatic insulin was significantly reduced (p<0.05) in the (Pro3)GIPLys16PAL-treated mice. These data demonstrate that acylation of Lys16 with palmitic acid in (Pro3)GIP does not improve its biological effectiveness as a GIP receptor antagonist.
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Affiliation(s)
- Victor A Gault
- School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, Northern Ireland, UK.
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25
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Flatt PR, Green BD. Nutrient regulation of pancreatic β-cell function in diabetes: problems and potential solutions. Biochem Soc Trans 2006; 34:774-8. [PMID: 17052195 DOI: 10.1042/bst0340774] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Increasing prevalence of obesity combined with longevity will produce an epidemic of Type 2 (non-insulin-dependent) diabetes in the next 20 years. This disease is associated with defects in insulin secretion, specifically abnormalities of insulin secretory kinetics and pancreatic β-cell glucose responsiveness. Mechanisms underlying β-cell dysfunction include glucose toxicity, lipotoxicity and β-cell hyperactivity. Defects at various sites in β-cell signal transduction pathways contribute, but no single lesion can account for the common form of Type 2 diabetes. Recent studies highlight diverse β-cell actions of GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic polypeptide). These intestinal hormones target the β-cell to stimulate glucose-dependent insulin secretion through activation of protein kinase A and associated pathways. Both increase gene expression and proinsulin biosynthesis, protect against apoptosis and stimulate replication/neogenesis of β-cells. Incretin hormones therefore represent an exciting future multi-action solution to correct β-cell defect in Type 2 diabetes.
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Affiliation(s)
- P R Flatt
- School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, UK.
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26
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Irwin N, Clarke GC, Green BD, Greer B, Harriott P, Gault VA, O'Harte FPM, Flatt PR. Evaluation of the antidiabetic activity of DPP IV resistant N-terminally modified versus mid-chain acylated analogues of glucose-dependent insulinotropic polypeptide. Biochem Pharmacol 2006; 72:719-28. [PMID: 16859646 DOI: 10.1016/j.bcp.2006.06.013] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2006] [Revised: 06/12/2006] [Accepted: 06/12/2006] [Indexed: 10/24/2022]
Abstract
Glucose dependent insulinotropic polypeptide (GIP) is a gastrointestinal hormone with therapeutic potential for type 2 diabetes due to its insulin-releasing and antihyperglycaemic actions. However, development of GIP-based therapies is limited by N-terminal degradation by DPP IV resulting in a very short circulating half-life. Numerous GIP analogues have now been generated exhibiting DPP IV resistance and extended bioactivity profiles. In this study, we report a direct comparison of the long-term antidiabetic actions of three such GIP molecules, N-AcGIP, GIP(Lys(37)PAL) and N-AcGIP(Lys(37)PAL) in obese diabetic (ob/ob) mice. An extended duration of action of each GIP analogue was demonstrated prior to examining the effects of once daily injections (25nmolkg(-1) body weight) over a 14-day period. Administration of either N-AcGIP, GIP(Lys(37)PAL) or N-AcGIP(Lys(37)PAL) significantly decreased non-fasting plasma glucose and improved glucose tolerance compared to saline treated controls. All three analogues significantly enhanced glucose and nutrient-induced insulin release, and improved insulin sensitivity. The metabolic and insulin secretory responses to native GIP were also enhanced in 14-day analogue treated mice, revealing no evidence of GIP-receptor desensitization. These effects were accompanied by significantly enhanced pancreatic insulin following N-AcGIP(Lys(37)PAL) and increased islet number and islet size in all three groups. Body weight, food intake and circulating glucagon were unchanged. These data demonstrate the therapeutic potential of once daily injection of enzyme resistant GIP analogues and indicate that N-AcGIP is equally as effective as related palmitate derivatised analogues of GIP.
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Affiliation(s)
- Nigel Irwin
- School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK.
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27
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Green BD, Lavery KS, Irwin N, O'harte FPM, Harriott P, Greer B, Bailey CJ, Flatt PR. Novel glucagon-like peptide-1 (GLP-1) analog (Val8)GLP-1 results in significant improvements of glucose tolerance and pancreatic beta-cell function after 3-week daily administration in obese diabetic (ob/ob) mice. J Pharmacol Exp Ther 2006; 318:914-21. [PMID: 16648370 DOI: 10.1124/jpet.105.097824] [Citation(s) in RCA: 41] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/19/2022] Open
Abstract
This study evaluates the antidiabetic potential of an enzyme-resistant analog, (Val8)GLP-1. The effects of daily administration of a novel dipeptidyl peptidase IV-resistant glucagon-like peptide-1 (GLP-1) analog, (Val8)GLP-1, on glucose tolerance and pancreatic beta-cell function were examined in obese-diabetic (ob/ob) mice. Acute intraperitoneal administration of (Val8)GLP-1 (6.25-25 nmol/kg) with glucose increased the insulin response and reduced the glycemic excursion in a dose-dependent manner. The effects of (Val8)GLP-1 were greater and longer lasting than native GLP-1. Once-daily subcutaneous administration of (Val8)GLP-1 (25 nmol/kg) for 21 days reduced plasma glucose concentrations, increased plasma insulin, and reduced body weight more than native GLP-1 without a significant change in daily food intake. Furthermore, (Val8)GLP-1 improved glucose tolerance, reduced the glycemic excursion after feeding, increased the plasma insulin response to glucose and feeding, and improved insulin sensitivity. These effects were consistently greater with (Val8)GLP-1 than with native GLP-1, and both peptides retained or increased their acute efficacy compared with initial administration. (Val8)GLP-1 treatment increased average islet area 1.2-fold without changing the number of islets, resulting in an increased number of larger islets. These data demonstrate that (Val8)GLP-1 is more effective and longer acting than native GLP-1 in obese-diabetic ob/ob mice.
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Affiliation(s)
- Brian D Green
- School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, Northern Ireland, UK.
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Brandt I, Lambeir AM, Maes MB, Scharpé S, De Meester I. Peptide substrates of dipeptidyl peptidases. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2006; 575:3-18. [PMID: 16700503 DOI: 10.1007/0-387-32824-6_1] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
Affiliation(s)
- Inger Brandt
- Laboratory of Medical Biochemistry, Department of Pharmaceutical Sciences, University of Antwerp, Universiteitsplein 1, B-2610 Antwerp, Belgium
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29
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Irwin N, Gault VA, Green BD, Greer B, Harriott P, Bailey CJ, Flatt PR, O'Harte FPM. Antidiabetic potential of two novel fatty acid derivatised, N-terminally modified analogues of glucose-dependent insulinotropic polypeptide (GIP): N-AcGIP(LysPAL16) and N-AcGIP(LysPAL37). Biol Chem 2005; 386:679-87. [PMID: 16207089 DOI: 10.1515/bc.2005.079] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023]
Abstract
Fatty acid derivatisation was used to develop two novel, long-acting, N-terminally modified, glucose-dependent insulinotropic polypeptide (GIP) analogues, N-AcGIP(LysPAL16) and N-AcGIP(LysPAL37). In contrast to GIP, which was rapidly degraded by in vitro incubation with dipeptidylpeptidase IV (DPP IV) (52% intact after 2 h), the analogues remained fully intact for up to 24 h. Both fatty acid-derivatised analogues stimulated cAMP production in GIP receptor Chinese hamster lung (CHL) fibroblasts (EC50 12.1-13.0 nM) and significantly improved in vitro insulin secretion from BRIN-BD11 cells (1.1- to 2.4-fold; p < 0.05 to p < 0.001) compared to control (5.6 mM glucose). Administration of N-AcGIP(LysPAL16) and N-AcGIP(LysPAL37) together with glucose in obese diabetic (ob/ob) mice significantly reduced the glycaemic excursion (1.4- and 1.5-fold, respectively; p < 0.05 to p < 0.01) and improved the insulinotropic response (1.5- and 2.3-fold, respectively; p < 0.01 to p < 0.001) compared to native peptide. Dose-response studies with N-AcGIP(LysPAL37) revealed that even the lowest concentration (6.25 nmol/kg) induced a highly significant decrease (1.4-fold; p < 0.001) in the overall glycaemic excursion, coupled with a significant increase (2.0-fold; p < 0.01) in circulating insulin. Furthermore, basal glucose values remained significantly reduced (p < 0.05) and insulin values increased 24 h following a single injection of N-AcGIP(LysPAL37). The glucose-lowering action of the fatty acid-derivatised peptide was greater than that of N-AcGIP. These data demonstrate that novel fatty acid-derivatised analogues of N-terminally modified AcGIP function as long-acting GIP-receptor agonists, with significant antidiabetic potential.
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Affiliation(s)
- Nigel Irwin
- School of Biomedical Sciences, University of Ulster, Coleraine, BT52 1SA, N. Ireland, UK.
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30
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Green BD, Liu HK, McCluskey JT, Duffy NA, O'Harte FPM, McClenaghan NH, Flatt PR. Function of a long-term, GLP-1-treated, insulin-secreting cell line is improved by preventing DPP IV-mediated degradation of GLP-1. Diabetes Obes Metab 2005; 7:563-9. [PMID: 16050949 DOI: 10.1111/j.1463-1326.2004.00430.x] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Glucagon-like peptide-1 (GLP-1) is an important insulinotropic hormone with potential in the treatment of type 2 diabetes. However, the short biological half-life of the peptide after cleavage by dipeptidylpeptidase IV (DPP IV) is a major limitation. Inhibition of DPP IV activity and the development of resistant GLP-1 analogues is the subject of ongoing research. In this study, we determined cell growth, insulin content, insulin accumulation and insulin secretory function of a insulin-secreting cell line cultured for 3 days with either GLP-1, GLP-1 plus the DPP IV inhibitor diprotin A (DPA) or stable N-acetyl-GLP-1. Native GLP-1 was rapidly degraded by DPP IV during culture with accumulation of the inactive metabolite GLP-1(9-36)amide. Inclusion of DPA or use of the DPP IV-resistant analogue, N-acetyl-GLP-1, improved cellular function compared to exposure to GLP-1 alone. Most notably, basal and accumulated insulin secretion was enhanced, and glucose responsiveness was improved. However, prolonged GLP-1 treatment resulted in GLP-1 receptor desensitization regardless of DPP IV status. The results indicate that prevention of DPP IV action is necessary for beneficial effects of GLP-1 on pancreatic beta cells and that prolonged exposure to GLP-1(9-36)amide may be detrimental to insulin secretory function. These observations also support the ongoing development of DPP-IV-resistant forms of GLP-1, such as N-acetyl-GLP-1.
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Affiliation(s)
- B D Green
- School of Biomedical Sciences, University of Ulster, Coleraine, N. Ireland, UK.
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31
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Green BD, Gault VA, O'Harte FPM, Flatt PR. A comparison of the cellular and biological properties of DPP-IV-resistant N-glucitol analogues of glucagon-like peptide-1 and glucose-dependent insulinotropic polypeptide. Diabetes Obes Metab 2005; 7:595-604. [PMID: 16050953 DOI: 10.1111/j.1463-1326.2004.00455.x] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
AIM The two major incretin hormones--glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP)--are being actively researched by the pharmaceutical industry because of their glucose-lowering and potential anti-diabetic properties. Unfortunately, the inactivation of GLP-1 and GIP in the circulation brought about by dipeptidyl-peptidase-IV (DPP-IV) degradation makes their biological actions short-lived. This study directly compares the cellular and biological properties of GLP-1, GIP and their N-terminally modified counterparts, with glucitol extension at positions His7 and Tyr1 respectively, to confer DPP-IV resistance. METHODS Using both the glucose-responsive pancreatic beta-cell line, BRIN BD11, and the obese diabetic (ob/ob) mouse, we assessed adenosine 3',5'-cyclic monophosphate (cAMP) production and insulinotropic action in vitro as well as in vivo glucose-lowering and insulin-releasing actions. RESULTS The results reveal that glycation of the N-terminus of GLP-1 or GIP stabilized both peptides against DPP-IV degradation. However, N-glucitol-GLP-1 displayed reduced cAMP production, insulinotropic activity and glucose-lowering potency, compared to native GLP-1. By contrast, N-glucitol-GIP exhibited substantially improved biological activities, compared to native GIP, and possessed similar or enhanced in vivo potency to GLP-1. N-terminal extension by means of glucitol addition is more beneficial to bioactivity of GIP than it is to GLP-1. CONCLUSIONS N-terminal glycation generates a super GIP agonist, which possesses acute in vivo glucose-lowering and insulinotropic actions superior to native GLP-1. Therefore, N-glucitol-GIP is a particularly attractive potential candidate molecule for drug therapy of type 2 diabetes.
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Affiliation(s)
- B D Green
- School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK.
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Hui H, Zhao X, Perfetti R. Structure and function studies of glucagon-like peptide-1 (GLP-1): the designing of a novel pharmacological agent for the treatment of diabetes. Diabetes Metab Res Rev 2005; 21:313-31. [PMID: 15852457 DOI: 10.1002/dmrr.553] [Citation(s) in RCA: 56] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/15/2023]
Abstract
Glucagon-like peptide-1 (GLP-1) is a proglucagon-derived peptide secreted from gut endocrine cells in response to nutrient ingestion. The multifaceted actions of GLP-1 include the following: (1) the stimulation of insulin secretion and of its gene expression, (2) the inhibition of glucagon secretion, (3) the inhibition of food intake, (4) the proliferation and differentiation of beta cells, and (5) the protection of beta-cells from apoptosis. The therapeutic utility of the native GLP-1 molecule is limited by its rapid enzymatic degradation by a serine protease termed dipeptidyl peptidase-IV (DPP-IV). The present article reviews the research studies aimed at elucidating the biosynthesis, metabolism, and molecular characteristics of GLP-1 since it is from these studies that the development of a GLP-1-like pharmacological agent may be derived.
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Affiliation(s)
- Hongxiang Hui
- Division of Endocrinology and Metabolism, Cedars-Sinai Medical Center, Los Angeles, California 90048, USA
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Irwin N, Green BD, Mooney MH, Greer B, Harriott P, Bailey CJ, Gault VA, O'Harte FPM, Flatt PR. A Novel, Long-Acting Agonist of Glucose-Dependent Insulinotropic Polypeptide Suitable for Once-Daily Administration in Type 2 Diabetes. J Pharmacol Exp Ther 2005; 314:1187-94. [PMID: 15923344 DOI: 10.1124/jpet.105.086082] [Citation(s) in RCA: 42] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/16/2023] Open
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is a gastrointestinal hormone with a potentially therapeutic role in type 2 diabetes. Rapid degradation by dipeptidylpeptidase IV has prompted the development of enzyme-resistant N-terminally modified analogs, but renal clearance still limits in vivo bioactivity. In this study, we report long-term antidiabetic effects of a novel, N-terminally protected, fatty acid-derivatized analog of GIP, N-AcGIP(LysPAL(37)), in obese diabetic (ob/ob) mice. Once-daily injections of N-AcGIP(LysPAL(37)) over a 14-day period significantly decreased plasma glucose, glycated hemoglobin, and improved glucose tolerance compared with ob/ob mice treated with saline or native GIP. Plasma insulin and pancreatic insulin content were significantly increased by N-AcGIP(LysPAL(37)). This was accompanied by a significant enhancement in the insulin response to glucose together with a notable improvement of insulin sensitivity. No evidence was found for GIP receptor desensitization and the metabolic effects of N-AcGIP(LysPAL(37)) were independent of any change in feeding or body weight. Similar daily injections of native GIP did not affect any of the parameters measured. These data demonstrate the ability of once-daily injections of N-terminally modified, fatty acid-derivatized analogs of GIP, such as N-AcGIP(LysPAL(37)), to improve diabetes control and to offer a new class of agents for the treatment of type 2 diabetes.
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Affiliation(s)
- Nigel Irwin
- School of Biomedical Sciences, University of Ulster, Coleraine, Northern Ireland, UK
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34
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Irwin N, Green BD, Gault VA, Greer B, Harriott P, Bailey CJ, Flatt PR, O'Harte FPM. Degradation, insulin secretion, and antihyperglycemic actions of two palmitate-derivitized N-terminal pyroglutamyl analogues of glucose-dependent insulinotropic polypeptide. J Med Chem 2005; 48:1244-50. [PMID: 15715491 DOI: 10.1021/jm049262s] [Citation(s) in RCA: 32] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Abstract
Exploitation of glucose-dependent insulinotropic polypeptide (GIP) is hindered by its short biological half-life and rapid renal clearance. To circumvent these problems, two novel acylated N-terminally modified GIP analogues, N-pGluGIP(LysPAL(16)) and N-pGluGIP(LysPAL(37)), were evaluated. In contrast to native GIP, both analogues were completely resistant to dipeptidyl peptidase IV degradation. In GIP-receptor transfected fibroblasts, N-pGluGIP(LysPAL(16)) and N-pGluGIP(LysPAL(37)) exhibited enhanced stimulation of cAMP production. Insulinotropic responses in clonal beta-cells were similar to native GIP. When administered together with glucose to ob/ob mice, the glycemic excursions were significantly less for both analogues and insulin responses were greater than native GIP. Extended insulinotropic and antihyperglycemic actions were also evident. These data indicate that palmitate-derivitized analogues of N-terminal pyroglutamyl GIP represent a novel class of stable, long-acting, and effective GIP analogues for potential type 2 diabetes therapy.
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Affiliation(s)
- Nigel Irwin
- School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, UK
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35
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Furman B, Pyne N, Flatt P, O'Harte F. Targeting beta-cell cyclic 3'5' adenosine monophosphate for the development of novel drugs for treating type 2 diabetes mellitus. A review. J Pharm Pharmacol 2005; 56:1477-92. [PMID: 15563754 DOI: 10.1211/0022357044805] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/31/2022]
Abstract
Cyclic 3'5'AMP is an important physiological amplifier of glucose-induced insulin secretion by the pancreatic islet beta-cell, where it is formed by the activity of adenylyl cyclase, especially in response to the incretin hormones GLP-1 (glucagon-like peptide-1) and GIP (glucose-dependent insulinotropic peptide). These hormones are secreted from the small intestine during and following a meal, and are important in producing a full insulin secretory response to nutrient stimuli. Cyclic AMP influences many steps involved in glucose-induced insulin secretion and may be important in regulating pancreatic islet beta-cell differentiation, growth and survival. Cyclic AMP (cAMP) itself is rapidly degraded in the pancreatic islet beta-cell by cyclic nucleotide phosphodiesterase (PDE) enzymes. This review discusses the possibility of targeting cAMP mechanisms in the treatment of type 2 diabetes mellitus, in which insulin release in response to glucose is impaired. This could be achieved by the use of GLP-1 or GIP to elevate cAMP in the pancreatic islet beta-cell. However, these peptides are normally rapidly degraded by dipeptidyl peptidase IV (DPP IV). Thus longer-acting analogues of GLP-1 and GIP, resistant to enzymic degradation, and orally active inhibitors of DPP IV have also been developed, and these agents were found to improve metabolic control in experimentally diabetic animals and in patients with type 2 diabetes. The use of selective inhibitors of type 3 phosphodiesterase (PDE3B), which is probably the important pancreatic islet beta-cell PDE isoform, would require their targeting to the islet beta-cell, because inhibition of PDE3B in adipocytes and hepatocytes would induce insulin resistance.
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Affiliation(s)
- Brian Furman
- Department of Physiology and Pharmacology, University of Strathclyde, Strathclyde Institute for Biomedical Sciences, Taylor Street, Glasgow G4 ONR, UK.
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36
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Green BD, Gault VA, Flatt PR, Harriott P, Greer B, O'Harte FPM. Comparative effects of GLP-1 and GIP on cAMP production, insulin secretion, and in vivo antidiabetic actions following substitution of Ala8/Ala2 with 2-aminobutyric acid. Arch Biochem Biophys 2004; 428:136-43. [PMID: 15246869 DOI: 10.1016/j.abb.2004.05.005] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2004] [Revised: 05/06/2004] [Indexed: 01/06/2023]
Abstract
The two major incretin hormones, glucagon-like peptide-1 (GLP-1), and glucose-dependent insulinotropic polypeptide (GIP), are currently being considered as prospective drug candidates for treatment of type 2 diabetes. Interest in these gut hormones was initially spurred by their potent insulinotropic activities, but a number of other antihyperglycaemic actions are now established. One of the foremost barriers in progressing GLP-1 and GIP to the clinic concerns their rapid degradation and inactivation by the ubiquitous enzyme, dipeptidyl peptidase IV (DPP IV). Here, we compare the DPP IV resistance and biological properties of Abu8/Abu2 (2-aminobutyric acid) substituted analogues of GLP-1 and GIP engineered to impart DPP IV resistance. Whereas (Abu8)GLP-1 was completely stable to human plasma (half-life >12 h), GLP-1, GIP, and (Abu2)GIP were rapidly degraded (half-lives: 6.2, 6.0, and 7.1 h, respectively). Native GIP, GLP-1, and particularly (Abu8)GLP-1 elicited significant adenylate cyclase and insulinotropic activity, while (Abu2)GIP was less effective. Similarly, in obese diabetic (ob/ob) mice, GIP, GLP-1, and (Abu8)GLP-1 displayed substantial glucose-lowering and insulin-releasing activities, whereas (Abu2)GIP was only weakly active. These studies illustrate divergent effects of penultimate amino acid Ala8/Ala2 substitution with Abu on the biological properties of GLP-1 and GIP, suggesting that (Abu8)GLP-1 represents a potential candidate for future therapeutic development.
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Affiliation(s)
- B D Green
- School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, Northern Ireland, UK.
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