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Zhu W, Tanday N, Lafferty RA, Flatt PR, Irwin N. Novel enzyme-resistant pancreatic polypeptide analogs evoke pancreatic beta-cell rest, enhance islet cell turnover, and inhibit food intake in mice. Biofactors 2024. [PMID: 38635341 DOI: 10.1002/biof.2059] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/14/2023] [Accepted: 04/02/2024] [Indexed: 04/20/2024]
Abstract
Pancreatic polypeptide (PP) is a postprandial hormone secreted from pancreatic islets that activates neuropeptide Y4 receptors (NPY4Rs). PP is known to induce satiety but effects at the level of the endocrine pancreas are less well characterized. In addition, rapid metabolism of PP by dipeptidyl peptidase-4 (DPP-4) limits the investigation of the effects of the native peptide. Therefore, in the present study, five novel amino acid substituted and/or fatty acid derivatized PP analogs were synthesized, namely [P3]PP, [K13Pal]PP, [P3,K13Pal]PP, [N-Pal]PP, and [N-Pal,P3]PP, and their impact on pancreatic beta-cell function, as well as appetite regulation and glucose homeostasis investigated. All PP analogs displayed increased resistance to DPP-4 degradation. In addition, all peptides inhibited alanine-induced insulin secretion from BRIN-BD11 beta cells. Native PP and related analogs (10-8 and 10-6 M), and especially [P3]PP and [K13Pal]PP, significantly protected against cytokine-induced beta-cell apoptosis and promoted cellular proliferation, with effects dependent on the NPY4R for all peptides barring [N-Pal,P3]PP. In mice, all peptides, except [N-Pal]PP and [N-Pal,P3]PP, evoked a dose-dependent (25, 75, and 200 nmol/kg) suppression of appetite, with native PP and [P3]PP further augmenting glucagon-like peptide-1 (GLP-1) and cholecystokinin (CCK) induced reductions of food intake. The PP peptides had no obvious detrimental effect on glucose tolerance and they did not noticeably impair the glucose-regulatory actions of GLP-1 or CCK. In conclusion, Pro3 amino acid substitution of PP, either alone or together with mid-chain acylation, creates PP analogs with benefits on beta-cell rest, islet cell turnover, and energy regulation that may be applicable to the treatment of diabetes and obesity.
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Affiliation(s)
- Wuyun Zhu
- Diabetes Research Centre, Schools of Biomedical Sciences and Pharmacy & Pharmaceutical Sciences, Ulster University, Coleraine, UK
| | - Neil Tanday
- Diabetes Research Centre, Schools of Biomedical Sciences and Pharmacy & Pharmaceutical Sciences, Ulster University, Coleraine, UK
| | - Ryan A Lafferty
- Diabetes Research Centre, Schools of Biomedical Sciences and Pharmacy & Pharmaceutical Sciences, Ulster University, Coleraine, UK
| | - Peter R Flatt
- Diabetes Research Centre, Schools of Biomedical Sciences and Pharmacy & Pharmaceutical Sciences, Ulster University, Coleraine, UK
| | - Nigel Irwin
- Diabetes Research Centre, Schools of Biomedical Sciences and Pharmacy & Pharmaceutical Sciences, Ulster University, Coleraine, UK
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2
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Pandey S, Mangmool S, Parichatikanond W. Multifaceted Roles of GLP-1 and Its Analogs: A Review on Molecular Mechanisms with a Cardiotherapeutic Perspective. Pharmaceuticals (Basel) 2023; 16:836. [PMID: 37375783 DOI: 10.3390/ph16060836] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/10/2023] [Revised: 06/01/2023] [Accepted: 06/01/2023] [Indexed: 06/29/2023] Open
Abstract
Diabetes is one of the chronic metabolic disorders which poses a multitude of life-debilitating challenges, including cardiac muscle impairment, which eventually results in heart failure. The incretin hormone glucagon-like peptide-1 (GLP-1) has gained distinct recognition in reinstating glucose homeostasis in diabetes, while it is now largely accepted that it has an array of biological effects in the body. Several lines of evidence have revealed that GLP-1 and its analogs possess cardioprotective effects by various mechanisms related to cardiac contractility, myocardial glucose uptake, cardiac oxidative stress and ischemia/reperfusion injury, and mitochondrial homeostasis. Upon binding to GLP-1 receptor (GLP-1R), GLP-1 and its analogs exert their effects via adenylyl cyclase-mediated cAMP elevation and subsequent activation of cAMP-dependent protein kinase(s) which stimulates the insulin release in conjunction with enhanced Ca2+ and ATP levels. Recent findings have suggested additional downstream molecular pathways stirred by long-term exposure of GLP-1 analogs, which pave the way for the development of potential therapeutic molecules with longer lasting beneficial effects against diabetic cardiomyopathies. This review provides a comprehensive overview of the recent advances in the understanding of the GLP-1R-dependent and -independent actions of GLP-1 and its analogs in the protection against cardiomyopathies.
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Affiliation(s)
- Sudhir Pandey
- Department of Pharmacology, Faculty of Pharmacy, Mahidol University, Bangkok 10400, Thailand
| | - Supachoke Mangmool
- Department of Pharmacology, Faculty of Science, Mahidol University, Bangkok 10400, Thailand
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Džidić-Krivić A, Kusturica J, Sher EK, Selak N, Osmančević N, Karahmet Farhat E, Sher F. Effects of intestinal flora on pharmacokinetics and pharmacodynamics of drugs. Drug Metab Rev 2023; 55:126-139. [PMID: 36916327 DOI: 10.1080/03602532.2023.2186313] [Citation(s) in RCA: 11] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/16/2023]
Abstract
Gut microbiota is known as unique collection of microorganisms (including bacteria, archaea, eukaryotes and viruses) that exist in a complex environment of the gut. Recently, this has become one of the most popular areas of research in medicine because this plays not only an important role in disease development, but gut microbiota also influences drug pharmacokinetics. These alterations in drug pharmacokinetic pathways and drug concentration in plasma and blood often lead to an increase in the incidence of toxicological events in patients. This review aims to present current knowledge of the most commonly used drugs in clinical practice and their dynamic interplay with the host's gut microbiota as well as the mechanisms underlying these metabolic processes and the consequent effect on their therapeutic efficacy and safety. These new findings set a foundation for the development of personalized treatments specific to each metabolism, maximizing drugs' therapeutic effects and minimizing the side effects because they are one of the major limiting factors in treating patients.
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Affiliation(s)
- Amina Džidić-Krivić
- Zenica Cantonal Hospital, Zenica, Bosnia and Herzegovina.,International Society of Engineering Science and Technology, Nottingham, UK
| | - Jasna Kusturica
- Faculty of Medicine, University of Sarajevo, Sarajevo, Bosnia and Herzegovina
| | - Emina Karahmet Sher
- Department of Biosciences, School of Science and Technology, Nottingham Trent University, Nottingham, UK
| | - Nejra Selak
- Dom zdravlja Zenica, Zenica, Bosnia and Herzegovina
| | | | - Esma Karahmet Farhat
- International Society of Engineering Science and Technology, Nottingham, UK.,Department of Food and Nutrition Research, Faculty of Food Technology, Juraj Strossmayer University of Osijek, Osijek, Croatia
| | - Farooq Sher
- Department of Engineering, School of Science and Technology, Nottingham Trent University, Nottingham, UK
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Kowluru RA. Retinopathy in a Diet-Induced Type 2 Diabetic Rat Model and Role of Epigenetic Modifications. Diabetes 2020; 69:689-698. [PMID: 31949005 PMCID: PMC7085254 DOI: 10.2337/db19-1009] [Citation(s) in RCA: 44] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/07/2019] [Accepted: 01/08/2020] [Indexed: 12/12/2022]
Abstract
Type 2 diabetes accounts for 90% of the population with diabetes, and these patients are generally obese and hyperlipidemic. In addition to hyperglycemia, hyperlipidemia is also closely related with diabetic retinopathy. The aim was to investigate retinopathy in a model closely mimicking the normal progression and metabolic features of the population with type 2 diabetes and elucidate the molecular mechanism. Retinopathy was evaluated in rats fed a 45% kcal as fat diet for 8 weeks before administering streptozotocin, 30 mg/kg body weight (T2D), and compared with age- and duration-matched type 1 diabetic rats (T1D) (60 mg/kg streptozotocin). The role of epigenetic modifications in mitochondrial damage was evaluated in retinal microvasculature. T2D rats were obese and severely hyperlipidemic, with impaired glucose and insulin tolerance compared with age-matched T1D rats. While at 4 months of diabetes, T1D rats had no detectable retinopathy, T2D rats had significant retinopathy, their mitochondrial copy numbers were lower, and mtDNA and Rac1 promoter DNA methylation was exacerbated. At 6 months, retinopathy was comparable in T2D and T1D rats, suggesting that obesity exaggerates hyperglycemia-induced epigenetic modifications, accelerating mitochondrial damage and diabetic retinopathy. Thus, maintenance of good lifestyle and BMI could be beneficial in regulating epigenetic modifications and preventing/retarding retinopathy in patients with diabetes.
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MESH Headings
- Animals
- DNA Methylation
- Diabetes Mellitus, Experimental/genetics
- Diabetes Mellitus, Experimental/metabolism
- Diabetes Mellitus, Type 2/etiology
- Diabetes Mellitus, Type 2/genetics
- Diabetes Mellitus, Type 2/metabolism
- Diabetic Retinopathy/genetics
- Diabetic Retinopathy/metabolism
- Diet, High-Fat/adverse effects
- Disease Models, Animal
- Epigenesis, Genetic
- Insulin Resistance/physiology
- Male
- Promoter Regions, Genetic
- Rats
- Rats, Sprague-Dawley
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Affiliation(s)
- Renu A Kowluru
- Kresge Eye Institute, Wayne State University, Detroit, MI
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Hu XK, Yin XH, Zhang HQ, Guo CF, Tang MX. Liraglutide attenuates the osteoblastic differentiation of MC3T3‑E1 cells by modulating AMPK/mTOR signaling. Mol Med Rep 2016; 14:3662-8. [PMID: 27600753 PMCID: PMC5042760 DOI: 10.3892/mmr.2016.5729] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2015] [Accepted: 07/29/2016] [Indexed: 01/13/2023] Open
Abstract
Liraglutide, a synthetic analogue of glucagon-like peptide-1, is utilized in the treatment of type 2 diabetes and obesity. Liraglutide has been previously demonstrated to prevent osteoblastic differentiation of human vascular smooth muscle cells, resulting in the slowing of arterial calcification, however, its effect on bone formation remains unclear. The present study investigated the effect of liraglutide on osteoblastic differentiation using Alizarin Red S staining, and examined the molecular mechanisms underlying the regulatory effect by western blot analysis. The present study demonstrated that protein expression levels of phosphorylated adenosine monophosphate-activated protein kinase (p-AMPK) were downregulated in MC3T3-E1 cells during osteoblastic differentiation in commercial osteogenic differentiation medium, whereas protein expression levels of transforming growth factor-β (TGF-β) and phosphorylated mammalian target of rapamycin (p-mTOR) increased. Liraglutide was subsequently demonstrated to dose-dependently attenuate the osteoblastic differentiation of MC3T3-E1 cells, to upregulate p-AMPK, and downregulate p-mTOR and TGF-β protein expression levels. Treatment with an AMPK-specific inhibitor, Compound C, eradicated the effect of liraglutide on osteoblastic differentiation, and p-mTOR and TGF-β downregulation. An mTOR activator, MHY1485, also abolished the inhibitory effect of liraglutide on osteoblastic differentiation, and resulted in p-mTOR and TGF-β downregulation, but did not attenuate the liraglutide-induced increase in p-AMPK protein expression levels. The results of the present study demonstrate that liraglutide attenuates osteoblastic differentiation of MC3T3-E1 cells via modulation of AMPK/mTOR signaling. The present study revealed a novel function of liraglutide, which contributes to the understanding of its pharmacological and physiological effects in clinical settings.
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Affiliation(s)
- Xiong-Ke Hu
- Department of Spine Surgery, Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Xin-Hua Yin
- Department of Spine Surgery, Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Hong-Qi Zhang
- Department of Spine Surgery, Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Chao-Feng Guo
- Department of Spine Surgery, Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
| | - Ming-Xing Tang
- Department of Spine Surgery, Xiangya Hospital of Central South University, Changsha, Hunan 410013, P.R. China
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Fransson L, dos Santos C, Wolbert P, Sjöholm Å, Rafacho A, Ortsäter H. Liraglutide counteracts obesity and glucose intolerance in a mouse model of glucocorticoid-induced metabolic syndrome. Diabetol Metab Syndr 2014; 6:3. [PMID: 24423471 PMCID: PMC3905931 DOI: 10.1186/1758-5996-6-3] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2013] [Accepted: 01/09/2014] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Glucocorticoid excess is commonly associated with diabetogenic effects, including insulin resistance and glucose intolerance. The effects of the long-term glucagon-like peptide 1 receptor agonist treatment on the metabolic syndrome-like conditions are not yet fully elucidated. Thus, we aimed to test whether long-term liraglutide treatment could be effective as a therapy to counteract the metabolic dysfunctions induced by chronic glucocorticoid exposure. METHODS Mice were given corticosterone or vehicle via their drinking water for five consecutive weeks. In addition, mice were treated with once-daily injections of either PBS or liraglutide. RESULTS Liraglutide treatment slowed progression towards obesity and ectopic fat deposition in liver that otherwise occurred in corticosterone-treated mice. The drug reduced the increment in serum insulin caused by corticosterone, but did not affect the reduction of insulin sensitivity. Furthermore, liraglutide improved glucose control in mice exposed to corticosterone as evident by a delay in the progression towards post-prandial hyperglycemia and enhanced glucose clearance during a glucose tolerance test. Glucose-stimulated C-peptide levels were higher in those mice that had received liraglutide and corticosterone compared to mice that had been treated with corticosterone alone, indicating a positive role of liraglutide for beta-cell function. Morphometric analysis revealed increased beta- and alpha-cell masses that were associated with more Ki67-positive islet cells in corticosterone-treated mice irrespective of whether they were co-treated with liraglutide or not. Liraglutide had no discernible effect on alpha-cell mass. CONCLUSION Liraglutide can be beneficial for subjects at risk of developing metabolic complications as a result of glucocorticoid excess.
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Affiliation(s)
- Liselotte Fransson
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Research Center Floor 3, 118 83, Stockholm, Sweden
| | - Cristiane dos Santos
- Department of Physiological Sciences, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Petra Wolbert
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Research Center Floor 3, 118 83, Stockholm, Sweden
| | - Åke Sjöholm
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Research Center Floor 3, 118 83, Stockholm, Sweden
- Department of Internal Medicine, Södertälje Hospital, SE-152 86, Södertälje, Sweden
- Department of Biochemistry and Molecular Biology, College of Medicine, University of South Alabama, Mobile, AL, USA
| | - Alex Rafacho
- Department of Physiological Sciences, Center of Biological Sciences, Federal University of Santa Catarina, Florianópolis, Brazil
| | - Henrik Ortsäter
- Department of Clinical Science and Education, Södersjukhuset, Karolinska Institutet, Research Center Floor 3, 118 83, Stockholm, Sweden
- Research Unit, Södertälje Hospital, SE-152 86, Södertälje, Sweden
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Abstract
During the last years, various novel anti-diabetic drugs have considerably enriched the therapeutic armamentarium for subjects with Type 2 diabetes. In the meantime, much interest has recently been focused on the potential cardiovascular and oncological adverse effects of these new therapies. As to glucagon-like peptide 1 (GLP-1) analogs, medullary thyroid tumors were reported to be more common in rodent toxicology studies with liraglutide, although the relevance of this finding in humans has been questioned. Analyses of sequential changes in calcitonin levels in several thousands of subjects did not reveal a relationship between liraglutide therapy and plasma calcitonin. Furthermore, no medullary thyroid cancer has been detected in humans taking liraglutide. Nevertheless, the long-term consequences of sustained GLP-1 receptor activation in the human thyroid remain unknown and deserve further investigation.
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Affiliation(s)
- M Gallo
- Oncological Endocrinology, AO Citta' della Salute e della Scienza-Molinette, Via Genova, 3, I-10137 Turin, Italy.
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