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Hu H, Xu W, Li Y, Wang Z, Wang S, Liu Y, Bai M, Lou Y, Yang Q. SIRT1 regulates endoplasmic reticulum stress-related organ damage. Acta Histochem 2024; 126:152134. [PMID: 38237370 DOI: 10.1016/j.acthis.2024.152134] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2023] [Revised: 01/05/2024] [Accepted: 01/12/2024] [Indexed: 02/07/2024]
Abstract
Endoplasmic reticulum (ER) stress plays a key role in the pathogenesis of several organ damages. Studies show that excessive ER stress (ERS) can destroy cellular homeostasis, causing cell damage and physiological dysfunction in various organs. In recent years, Sirtuin1 (SIRT1) has become a research hotspot on ERS. Increasing evidence suggests that SIRT1 plays a positive role in various ERS-induced organ damage via multiple mechanisms, including inhibiting cellular apoptosis and promoting autophagy. SIRT1 can also alleviate liver, heart, lung, kidney, and intestinal damage by inhibiting ERS. We discuss the possible mechanism of SIRT1, explore potential therapeutic targets of diseases, and provide a theoretical basis for treating ERS-related diseases.
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Affiliation(s)
- He Hu
- Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Weichao Xu
- Department of Gastroenterology, Hebei Provincial Hospital of Traditional Chinese Medicine, Shijiazhuang, China
| | - Yan Li
- Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Zhicheng Wang
- Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Siyue Wang
- Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Yansheng Liu
- Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Minan Bai
- Hebei University of Chinese Medicine, Shijiazhuang, China
| | - Yingying Lou
- Department of Gastroenterology, Hebei Provincial Hospital of Traditional Chinese Medicine, Shijiazhuang, China.
| | - Qian Yang
- Department of Gastroenterology, Hebei Provincial Hospital of Traditional Chinese Medicine, Shijiazhuang, China
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Bai J, Zhang H, Yang Z, Li P, Liu B, Li D, Liang S, Wang Q, Li Z, Zhang J, Chen S, Hou G, Li Y. On demand regulation of blood glucose level by biocompatible oxidized starch-Con A nanogels for glucose-responsive release of exenatide. J Control Release 2022; 352:673-684. [PMID: 36374646 DOI: 10.1016/j.jconrel.2022.10.039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2022] [Revised: 10/18/2022] [Accepted: 10/22/2022] [Indexed: 11/09/2022]
Abstract
Diabetes mellitus is a long-term chronic disease characterized by abnormal high level blood glucose (BG). An artificial closed-loop system that mimics pancreatic β-cells and releases insulin on demand has potential to improve the therapeutic efficiency of diabetes. Herein, a lectin Concanavalin A modified oxidized starch nanogel was designed to regulate glucose dynamically according to different glucose concentrations. The nanogels were formed by double cross-linking the Concanavalin A and glucose units on oxidized starch via specific binding and amide bonds to achieve the high drug loading and glucose responsiveness. The results showed that oxidized starch nanogels prolonged the half-life of antidiabetic peptide drug exenatide and released it in response to high BG concentrations. It could absorb BG at a high level and maintain glucose homeostasis. Besides, the oxidized starch nanogels performed well in recovering regular BG level from hyperglycemia state and maintaining in euglycemia state that fitted in a biological rhythm. In addition, the nanogels showed high biocompatibility in vivo and could improve plasma half-life and therapeutic efficacy of exenatide. Overall, the nanogels protected peptide drugs from degradation in plasma as a glucose-responsive platform showing a high potential for peptide drugs delivery and antidiabetic therapy.
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Affiliation(s)
- Jie Bai
- Research Center of Food Colloids and Delivery of Functionality, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China
| | - Huijuan Zhang
- Research Center of Food Colloids and Delivery of Functionality, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China
| | - Zhi Yang
- School of Food and Advanced Technology, Massey University, Auckland 0632, New Zealand
| | - Pinglan Li
- Research Center of Food Colloids and Delivery of Functionality, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China
| | - Bin Liu
- Department of Nutrition and Health, China Agricultural University, Beijing 100193, PR China
| | - Dan Li
- Research Center of Food Colloids and Delivery of Functionality, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China
| | - Shuang Liang
- Department of Nutrition and Health, China Agricultural University, Beijing 100193, PR China
| | - Qimeng Wang
- Research Center of Food Colloids and Delivery of Functionality, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China
| | - Zekun Li
- Research Center of Food Colloids and Delivery of Functionality, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China
| | - Jipeng Zhang
- Research Center of Food Colloids and Delivery of Functionality, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China
| | - Shanan Chen
- Research Center of Food Colloids and Delivery of Functionality, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China
| | - Guohua Hou
- Research Center of Food Colloids and Delivery of Functionality, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China
| | - Yuan Li
- Research Center of Food Colloids and Delivery of Functionality, College of Food Science and Nutritional Engineering, China Agricultural University, Beijing 100083, PR China.
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Ferrari F, Moretti A, Villa RF. Incretin-based drugs as potential therapy for neurodegenerative diseases: current status and perspectives. Pharmacol Ther 2022; 239:108277. [DOI: 10.1016/j.pharmthera.2022.108277] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2022] [Revised: 08/26/2022] [Accepted: 08/29/2022] [Indexed: 10/14/2022]
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Han Y, Liu W, Chen L, Xin X, Wang Q, Zhang X, Jin M, Gao Z, Huang W. Effective oral delivery of Exenatide-Zn 2+ complex through distal ileum-targeted double layers nanocarriers modified with deoxycholic acid and glycocholic acid in diabetes therapy. Biomaterials 2021; 275:120944. [PMID: 34153783 DOI: 10.1016/j.biomaterials.2021.120944] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2021] [Revised: 05/28/2021] [Accepted: 05/28/2021] [Indexed: 12/29/2022]
Abstract
The oral administration route is popular with T2DM patients because they need convenience in lifelong medication. At present, oral Exenatide is not available on the market and therefore the relevant studies are valuable. Herein, we constructed a novel dual cholic acid-functionalized nanoparticle for oral delivery of Exenatide, which was based on the functionalized materials of deoxycholic acid-low molecular weight protamine and glycocholic acid-poly (ethylene glycol)-b-polysialic acid. The hydrophobic deoxycholic acid strengthened the nanoparticles and the hydrophilic glycolic acid targeted to specific transporter. We first condensed Exenatide-Zn2+ complex with deoxycholic acid-low molecular weight protamine to prepare nanocomplexes with ζ-potentials of +8 mV and sizes of 95 nm. Then, we used glycocholic acid-poly (ethylene glycol)-b-polysialic acid copolymers masking the positive charge of nanocomplexes to prepare nanoparticles with negative charges of -22 mV and homogeneous sizes of 140 nm. As a result, this dual cholic acid-functionalized nanoparticle demonstrated enhanced uptake and transport of Exenatide, and a special targeting to apical sodium-dependent cholic acid transporter in vitro. Moreover, in vivo studies showed that the nanoparticle effectively accumulated in distal ileum, raised the plasma concentration of Exenatide, prolonged hypoglycemic effect, reduced blood lipid levels, and lightened organ lesions.
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Affiliation(s)
- Ying Han
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Department of Pharmaceutics, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Wei Liu
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Department of Pharmaceutics, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Liqing Chen
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Department of Pharmaceutics, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Xin Xin
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Department of Pharmaceutics, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Qiming Wang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Department of Pharmaceutics, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Xintong Zhang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Department of Pharmaceutics, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Mingji Jin
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Department of Pharmaceutics, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China
| | - Zhonggao Gao
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Department of Pharmaceutics, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China.
| | - Wei Huang
- State Key Laboratory of Bioactive Substance and Function of Natural Medicines, Department of Pharmaceutics, Institute of Materia Medica, Chinese Academy of Medical Sciences and Peking Union Medical College, Beijing, 100050, China.
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Ferrari F, Moretti A, Villa RF. The treament of hyperglycemia in acute ischemic stroke with incretin-based drugs. Pharmacol Res 2020; 160:105018. [PMID: 32574826 DOI: 10.1016/j.phrs.2020.105018] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/31/2020] [Revised: 05/21/2020] [Accepted: 06/10/2020] [Indexed: 12/14/2022]
Abstract
Stroke is a major cause of mortality and morbidity worldwide. Considerable experimental and clinical evidence suggests that both diabetes mellitus (DM) and post-stroke hyperglycemia are associated with increased mortality rate and worsened clinical conditions in acute ischemic stroke (AIS) patients. Insulin treatment does not seem to provide convincing benefits for these patients, therefore prompting a change of strategy. The selective agonists of Glucagon-Like Peptide-1 Receptors (GLP-1Ras) and the Inhibitors of Dipeptidyl Peptidase-IV (DPP-IVIs, gliptins) are two newer classes of glucose-lowering drugs used for the treatment of DM. This review examines in detail the rationale for their development and the physicochemical, pharmacokinetic and pharmacodynamic properties and clinical activities. Emphasis will be placed on their neuroprotective effects at cellular and molecular levels in experimental models of acute cerebral ischemia. In perspective, an adequate basis does exist for a novel therapeutic approach to hyperglycemia in AIS patients through the additive treatment with GLP-1Ras plus DPP-IVIs.
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Affiliation(s)
- Federica Ferrari
- Department of Advanced Diagnostic and Therapeutic Technologies, Section of Neuroradiology, ASST Grande Ospedale Metropolitano Niguarda, Piazza Ospedale Maggiore 3, 20162 Milano, Italy; Departments of Biology-Biotechnology and Chemistry, Laboratory of Pharmacology and Molecular Medicine of Central Nervous System, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | - Antonio Moretti
- Departments of Biology-Biotechnology and Chemistry, Laboratory of Pharmacology and Molecular Medicine of Central Nervous System, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy
| | - Roberto Federico Villa
- Departments of Biology-Biotechnology and Chemistry, Laboratory of Pharmacology and Molecular Medicine of Central Nervous System, University of Pavia, Via Ferrata 9, 27100 Pavia, Italy.
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Zhang X, Jiang H, Ma X, Wu H. Increased serum level and impaired response to glucose fluctuation of asprosin is associated with type 2 diabetes mellitus. J Diabetes Investig 2020; 11:349-355. [PMID: 31529619 PMCID: PMC7078095 DOI: 10.1111/jdi.13148] [Citation(s) in RCA: 38] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/23/2019] [Revised: 08/04/2019] [Accepted: 09/13/2019] [Indexed: 11/30/2022] Open
Abstract
AIMS/INTRODUCTION Asprosin is a novel secreted adipokine that is induced by fasting and promotes hepatic glucose release. In healthy humans, circulating asprosin shows circadian oscillation with an acute drop coinciding with the onset of eating. The present study investigated whether this circadian oscillation still exists in patients with type 2 diabetes mellitus. MATERIALS AND METHODS We recruited 60 patients with type 2 diabetes mellitus and 60 individuals with normal glucose tolerance (NGT). All participants completed a 75-g oral glucose tolerance test. Fasting and 2-h postprandial serum asprosin concentrations were measured by the enzyme-linked immunosorbent assay method. Partial correlation coefficients were calculated to analyze the relationships between serum asprosin level and parameters of glucose metabolism. Multiple logistic regression analysis was used to determine the association of serum asprosin level with diabetes. RESULTS Both fasting and postprandial asprosin levels were significantly higher in patients with type 2 diabetes mellitus. The postprandial asprosin level was apparently lower than fasting asprosin level in individuals with NGT. The fasting asprosin level closely correlated with type 2 diabetes mellitus after multiple adjustment (odds ratio 2.329, P = 0.023). Asprosin correlated negatively with change in blood glucose (r = -0.502, P < 0.001) and change in C-peptide (r = -0.467, P < 0.001) in individuals with NGT, but not in type 2 diabetes mellitus patients. CONCLUSIONS Serum asprosin level decreased coinciding with the onset of the oral glucose tolerance test in individuals with NGT, whereas this circadian oscillation was disturbed in type 2 diabetes mellitus patients. The impaired response of asprosin to glucose fluctuation in type 2 diabetes mellitus patients might be one of the reasons for the onset of type 2 diabetes mellitus.
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Affiliation(s)
- Xinyue Zhang
- Health Management CenterShandong Provincial Qianfoshan HospitalThe First Affiliated‐Hospital of Shandong First Medical UniversityJinanChina
| | - Hui Jiang
- Health Management CenterShandong Provincial Qianfoshan HospitalThe First Affiliated‐Hospital of Shandong First Medical UniversityJinanChina
| | - Xiaojing Ma
- Health Management CenterShandong Provincial Qianfoshan HospitalThe First Affiliated‐Hospital of Shandong First Medical UniversityJinanChina
| | - Hongyan Wu
- Health Management CenterShandong Provincial Qianfoshan HospitalThe First Affiliated‐Hospital of Shandong First Medical UniversityJinanChina
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Sarmiento BE, Santos Menezes LF, Schwartz EF. Insulin Release Mechanism Modulated by Toxins Isolated from Animal Venoms: From Basic Research to Drug Development Prospects. Molecules 2019; 24:E1846. [PMID: 31091684 PMCID: PMC6571724 DOI: 10.3390/molecules24101846] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2019] [Revised: 04/23/2019] [Accepted: 05/09/2019] [Indexed: 12/12/2022] Open
Abstract
Venom from mammals, amphibians, snakes, arachnids, sea anemones and insects provides diverse sources of peptides with different potential medical applications. Several of these peptides have already been converted into drugs and some are still in the clinical phase. Diabetes type 2 is one of the diseases with the highest mortality rate worldwide, requiring specific attention. Diverse drugs are available (e.g., Sulfonylureas) for effective treatment, but with several adverse secondary effects, most of them related to the low specificity of these compounds to the target. In this context, the search for specific and high-affinity compounds for the management of this metabolic disease is growing. Toxins isolated from animal venom have high specificity and affinity for different molecular targets, of which the most important are ion channels. This review will present an overview about the electrical activity of the ion channels present in pancreatic β cells that are involved in the insulin secretion process, in addition to the diversity of peptides that can interact and modulate the electrical activity of pancreatic β cells. The importance of prospecting bioactive peptides for therapeutic use is also reinforced.
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Affiliation(s)
- Beatriz Elena Sarmiento
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF 70910-900, Brazil.
| | - Luis Felipe Santos Menezes
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF 70910-900, Brazil.
| | - Elisabeth F Schwartz
- Departamento de Ciências Fisiológicas, Instituto de Ciências Biológicas, Universidade de Brasília, Brasília, DF 70910-900, Brazil.
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Bader M, Li Y, Lecca D, Rubovitch V, Tweedie D, Glotfelty E, Rachmany L, Kim HK, Choi HI, Hoffer BJ, Pick CG, Greig NH, Kim DS. Pharmacokinetics and efficacy of PT302, a sustained-release Exenatide formulation, in a murine model of mild traumatic brain injury. Neurobiol Dis 2019; 124:439-453. [PMID: 30471415 PMCID: PMC6710831 DOI: 10.1016/j.nbd.2018.11.023] [Citation(s) in RCA: 25] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2018] [Revised: 10/29/2018] [Accepted: 11/20/2018] [Indexed: 12/15/2022] Open
Abstract
Traumatic brain injury (TBI) is a neurodegenerative disorder for which no effective pharmacological treatment is available. Glucagon-like peptide 1 (GLP-1) analogues such as Exenatide have previously demonstrated neurotrophic and neuroprotective effects in cellular and animal models of TBI. However, chronic or repeated administration was needed for efficacy. In this study, the pharmacokinetics and efficacy of PT302, a clinically available sustained-release Exenatide formulation (SR-Exenatide) were evaluated in a concussive mild (m)TBI mouse model. A single subcutaneous (s.c.) injection of PT302 (0.6, 0.12, and 0.024 mg/kg) was administered and plasma Exenatide concentrations were time-dependently measured over 3 weeks. An initial rapid regulated release of Exenatide in plasma was followed by a secondary phase of sustained-release in a dose-dependent manner. Short- and longer-term (7 and 30 day) cognitive impairments (visual and spatial deficits) induced by weight drop mTBI were mitigated by a single post-injury treatment with Exenatide delivered by s.c. injection of PT302 in clinically translatable doses. Immunohistochemical evaluation of neuronal cell death and inflammatory markers, likewise, cross-validated the neurotrophic and neuroprotective effects of SR-Exenatide in this mouse mTBI model. Exenatide central nervous system concentrations were 1.5% to 2.0% of concomitant plasma levels under steady-state conditions. These data demonstrate a positive beneficial action of PT302 in mTBI. This convenient single, sustained-release dosing regimen also has application for other neurological disorders, such as Alzheimer's disease, Parkinson's disease, multiple system atrophy and multiple sclerosis where prior preclinical studies, likewise, have demonstrated positive Exenatide actions.
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Affiliation(s)
- Miaad Bader
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Yazhou Li
- Drug Design and Development Section, Translational Gerontology Branch, Intramural Research Program, National Institutes of Health, National Institute on Aging, Baltimore, MD, USA
| | - Daniela Lecca
- Drug Design and Development Section, Translational Gerontology Branch, Intramural Research Program, National Institutes of Health, National Institute on Aging, Baltimore, MD, USA
| | - Vardit Rubovitch
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - David Tweedie
- Drug Design and Development Section, Translational Gerontology Branch, Intramural Research Program, National Institutes of Health, National Institute on Aging, Baltimore, MD, USA
| | - Elliot Glotfelty
- Drug Design and Development Section, Translational Gerontology Branch, Intramural Research Program, National Institutes of Health, National Institute on Aging, Baltimore, MD, USA; Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
| | - Lital Rachmany
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Hee Kyung Kim
- Peptron Inc., Yuseong-gu, Daejeon, Republic of Korea
| | - Ho-Il Choi
- Peptron Inc., Yuseong-gu, Daejeon, Republic of Korea
| | - Barry J Hoffer
- Department of Neurosurgery, Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Chaim G Pick
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv 69978, Israel; Sagol School of Neuroscience, Tel-Aviv University, Tel-Aviv 69978, Israel; Center for the Biology of Addictive Diseases, Tel-Aviv University, Tel-Aviv 69978, Israel
| | - Nigel H Greig
- Drug Design and Development Section, Translational Gerontology Branch, Intramural Research Program, National Institutes of Health, National Institute on Aging, Baltimore, MD, USA.
| | - Dong Seok Kim
- Drug Design and Development Section, Translational Gerontology Branch, Intramural Research Program, National Institutes of Health, National Institute on Aging, Baltimore, MD, USA; Department of Neuroscience, Karolinska Institute, Stockholm, Sweden
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Post-treatment with PT302, a long-acting Exendin-4 sustained release formulation, reduces dopaminergic neurodegeneration in a 6-Hydroxydopamine rat model of Parkinson's disease. Sci Rep 2018; 8:10722. [PMID: 30013201 PMCID: PMC6048117 DOI: 10.1038/s41598-018-28449-z] [Citation(s) in RCA: 30] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2018] [Accepted: 06/13/2018] [Indexed: 02/07/2023] Open
Abstract
We previously demonstrated that pretreatment with Exendin-4, a glucagon-like peptide-1 (GLP-1) receptor agonist, reduces 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) -mediated dopaminergic neurodegeneration. The use of GLP-1 or Exendin-4 for Parkinson's disease (PD) patients is limited by their short half-lives. The purpose of this study was to evaluate a new extended release Exendin-4 formulation, PT302, in a rat model of PD. Subcutaneous administration of PT302 resulted in sustained elevations of Exendin-4 in plasma for >20 days in adult rats. To define an efficacious dose within this range, rats were administered PT302 once every 2 weeks either before or following the unilaterally 6-hydroxydopamine lesioning. Pre- and post-treatment with PT302 significantly reduced methamphetamine-induced rotation after lesioning. For animals given PT302 post lesion, blood and brain samples were collected on day 47 for measurements of plasma Exendin-4 levels and brain tyrosine hydroxylase immunoreactivity (TH-IR). PT302 significantly increased TH-IR in the lesioned substantia nigra and striatum. There was a significant correlation between plasma Exendin-4 levels and TH-IR in the substantia nigra and striatum on the lesioned side. Our data suggest that post-treatment with PT302 provides long-lasting Exendin-4 release and reduces neurodegeneration of nigrostriatal dopaminergic neurons in a 6-hydroxydopamine rat model of PD at a clinically relevant dose.
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