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Hölscher C. Glucagon-like peptide 1 and glucose-dependent insulinotropic peptide hormones and novel receptor agonists protect synapses in Alzheimer’s and Parkinson’s diseases. Front Synaptic Neurosci 2022; 14:955258. [PMID: 35965783 PMCID: PMC9363704 DOI: 10.3389/fnsyn.2022.955258] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Accepted: 07/06/2022] [Indexed: 12/25/2022] Open
Abstract
Glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic peptide (GIP) are peptide hormones and growth factors. A major pathological feature of both Alzheimer’s dis-ease (AD) and Parkinson’s disease (PD) is the loss of synaptic transmission in the cortex in AD and the loss of dopaminergic synapses in the nigra-striatal dopaminergic projection. Several studies demonstrate that GLP-1 and GIP receptor agonists protect synapses and synaptic transmission from the toxic events that underlie AD and PD. In a range of AD animal models, treatment with GLP-1, GIP, or dual-GLP-1/GIP receptor agonists effectively protected cognition, synaptic trans-mission, long-term potentiation (LTP), and prevented the loss of synapses and neurons. In PD models, dopaminergic production resumed and synapses became functional again. Importantly, the GLP-1 receptor agonists exendin-4 and liraglutide have shown good protective effects in clinical trials in AD and PD patients. Studies show that growth factors and peptide drugs that can cross the blood–brain barrier (BBB) better are more potent than those that do not cross the BBB. We therefore developed dual-GLP-1/GIP receptor agonists that can cross the BBB at an enhanced rate and showed superior protective properties on synapses in animal models of AD and PD.
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Affiliation(s)
- Christian Hölscher
- Academy of Chinese Medical Sciences, Henan University of Chinese Medicine, Zhengzhou, China
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2
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Tsermpini EE, Goričar K, Kores Plesničar B, Plemenitaš Ilješ A, Dolžan V. Genetic Variability of Incretin Receptors and Alcohol Dependence: A Pilot Study. Front Mol Neurosci 2022; 15:908948. [PMID: 35754710 PMCID: PMC9218814 DOI: 10.3389/fnmol.2022.908948] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/09/2022] [Indexed: 11/13/2022] Open
Abstract
Alcohol dependence is a chronic mental disorder that leads to decreased quality of life for patients and their relatives and presents a considerable burden to society. Incretin hormones, such as glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide 1 (GLP-1) are endogenous gut-brain peptides, which can travel across the blood-brain barrier and access the nervous system. Their respective receptors, GIPR and GLP-1R, are expressed in the reward-related brain areas and are involved in memory formation and neurogenesis, which results in behavioral changes in rodent models. The current study investigated the potential association of genetic variability of incretin receptors with alcohol dependence and alcohol-related psychosymptomatology. Alcohol dependence and comorbid psychosymptomatology were assessed in a cohort of Slovenian male participants, comprised of 89 hospitalized alcohol-dependent patients, 98 abstinent alcohol-dependent patients, and 93 healthy blood donors. All participants were genotyped for GIPR rs1800437 and GLP1R rs10305420 and rs6923761 polymorphisms. For the statistical analysis Kruskal-Wall and Mann-Whitney tests were used in additive and dominant genetic models. Our findings indicated that GIPR rs1800437 genotypes were associated with an increased risk of alcohol dependence. Statistically significant association between GIPR rs1800437 GG genotype and Brief Social Phobia Scale scores were observed in the abstinent alcohol-dependent patients, while GLP1R rs6923761 GG genotype was associated with Zung anxiety scores in healthy controls. Our pilot study indicates that GIPR rs1800437 may play some role in susceptibility to alcohol dependence, as well as in alcohol-related psychosymptomatology symptoms. To our knowledge, this is the first study that indicates the involvement of GIPR in alcohol dependence. However, studies with larger cohorts are needed to confirm these preliminary findings.
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Affiliation(s)
- Evangelia Eirini Tsermpini
- Pharmacogenetics Laboratory, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Katja Goričar
- Pharmacogenetics Laboratory, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | - Blanka Kores Plesničar
- University Psychiatric Clinic, Ljubljana, Slovenia
- Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
| | | | - Vita Dolžan
- Pharmacogenetics Laboratory, Institute of Biochemistry and Molecular Genetics, Faculty of Medicine, University of Ljubljana, Ljubljana, Slovenia
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3
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Ko J, Jang S, Kwon W, Kim SY, Jang S, Kim E, Ji YR, Park S, Kim MO, Choi SK, Cho DH, Lee HS, Lim SG, Ryoo ZY. Protective Effect of GIP against Monosodium Glutamate-Induced Ferroptosis in Mouse Hippocampal HT-22 Cells through the MAPK Signaling Pathway. Antioxidants (Basel) 2022; 11:antiox11020189. [PMID: 35204073 PMCID: PMC8868324 DOI: 10.3390/antiox11020189] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2021] [Revised: 01/10/2022] [Accepted: 01/17/2022] [Indexed: 02/08/2023] Open
Abstract
The effect of glucose-dependent insulinotropic polypeptide (GIP) on cells under oxidative stress induced by glutamate, a neurotransmitter, and the underlying molecular mechanisms were assessed in the present study. We found that in the pre-treatment of HT-22 cells with glutamate in a dose-dependent manner, intracellular ROS were excessively generated, and additional cell damage occurred in the form of lipid peroxidation. The neurotoxicity caused by excessive glutamate was found to be ferroptosis and not apoptosis. Other factors (GPx-4, Nrf2, Nox1 and Hspb1) involved in ferroptosis were also identified. In other words, it was confirmed that GIP increased the activity of sub-signalling molecules in the process of suppressing ferroptosis as an antioxidant and maintained a stable cell cycle even under glutamate-induced neurotoxicity. At the same time, in HT-22 cells exposed to ferroptosis as a result of excessive glutamate accumulation, GIP sustained cell viability by activating the mitogen-activated protein kinase (MAPK) signalling pathway. These results suggest that the overexpression of the GIP gene increases cell viability by regulating mechanisms related to cytotoxicity and reactive oxygen species production in hippocampal neuronal cell lines.
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Affiliation(s)
- Jiwon Ko
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu 41566, Korea; (J.K.); (S.J.); (S.-Y.K.); (S.J.); (Y.-R.J.); (D.-H.C.); (H.-S.L.)
| | - Soyoung Jang
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu 41566, Korea; (J.K.); (S.J.); (S.-Y.K.); (S.J.); (Y.-R.J.); (D.-H.C.); (H.-S.L.)
| | - Wookbong Kwon
- Core Protein Resources Center, DGIST, Daegu 42988, Korea; (W.K.); (S.-K.C.)
- Division of Biotechnology, DGIST, Daegu 42988, Korea
| | - Si-Yong Kim
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu 41566, Korea; (J.K.); (S.J.); (S.-Y.K.); (S.J.); (Y.-R.J.); (D.-H.C.); (H.-S.L.)
| | - Soyeon Jang
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu 41566, Korea; (J.K.); (S.J.); (S.-Y.K.); (S.J.); (Y.-R.J.); (D.-H.C.); (H.-S.L.)
| | - Eungyung Kim
- Department of Animal Science and Biotechnology, Kyungpook National University, Sangju-si 37224, Korea; (E.K.); (M.-O.K.)
| | - Young-Rae Ji
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu 41566, Korea; (J.K.); (S.J.); (S.-Y.K.); (S.J.); (Y.-R.J.); (D.-H.C.); (H.-S.L.)
- Section on Sensory Cell Regeneration and Development, Laboratory of Molecular Biology, National Institutes of Health, Bethesda, MD 20892, USA
| | - Sijun Park
- School of Life Science, Kyungpook National University, Daegu 42988, Korea;
| | - Myoung-Ok Kim
- Department of Animal Science and Biotechnology, Kyungpook National University, Sangju-si 37224, Korea; (E.K.); (M.-O.K.)
| | - Seong-Kyoon Choi
- Core Protein Resources Center, DGIST, Daegu 42988, Korea; (W.K.); (S.-K.C.)
- Division of Biotechnology, DGIST, Daegu 42988, Korea
| | - Dong-Hyung Cho
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu 41566, Korea; (J.K.); (S.J.); (S.-Y.K.); (S.J.); (Y.-R.J.); (D.-H.C.); (H.-S.L.)
- Brain Science and Engineering Institute, Kyungpook National University, Daegu 42988, Korea
| | - Hyun-Shik Lee
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu 41566, Korea; (J.K.); (S.J.); (S.-Y.K.); (S.J.); (Y.-R.J.); (D.-H.C.); (H.-S.L.)
| | - Su-Geun Lim
- School of Life Science, Kyungpook National University, Daegu 42988, Korea;
- Correspondence: (S.-G.L.); (Z.-Y.R.)
| | - Zae-Young Ryoo
- BK21 FOUR KNU Creative BioResearch Group, School of Life Sciences, Kyungpook National University, Daegu 41566, Korea; (J.K.); (S.J.); (S.-Y.K.); (S.J.); (Y.-R.J.); (D.-H.C.); (H.-S.L.)
- Correspondence: (S.-G.L.); (Z.-Y.R.)
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Wang XS, Jiang YL, Lu L, Feng B, Ma X, Zhang K, Guan SY, Yang L, Fan QY, Zhu XC, Yang F, Qi JY, Yang LK, Li XB, Zhao MG, Jiang W, Tian Z, Liu SB. Activation of GIPR Exerts Analgesic and Anxiolytic-Like Effects in the Anterior Cingulate Cortex of Mice. Front Endocrinol (Lausanne) 2022; 13:887238. [PMID: 35712239 PMCID: PMC9196593 DOI: 10.3389/fendo.2022.887238] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/01/2022] [Accepted: 04/29/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Chronic pain is defined as pain that persists typically for a period of over six months. Chronic pain is often accompanied by an anxiety disorder, and these two tend to exacerbate each other. This can make the treatment of these conditions more difficult. Glucose-dependent insulinotropic polypeptide (GIP) is a member of the incretin hormone family and plays a critical role in glucose metabolism. Previous research has demonstrated the multiple roles of GIP in both physiological and pathological processes. In the central nervous system (CNS), studies of GIP are mainly focused on neurodegenerative diseases; hence, little is known about the functions of GIP in chronic pain and pain-related anxiety disorders. METHODS The chronic inflammatory pain model was established by hind paw injection with complete Freund's adjuvant (CFA) in C57BL/6 mice. GIP receptor (GIPR) agonist (D-Ala2-GIP) and antagonist (Pro3-GIP) were given by intraperitoneal injection or anterior cingulate cortex (ACC) local microinjection. Von Frey filaments and radiant heat were employed to assess the mechanical and thermal hypersensitivity. Anxiety-like behaviors were detected by open field and elevated plus maze tests. The underlying mechanisms in the peripheral nervous system and CNS were explored by GIPR shRNA knockdown in the ACC, enzyme-linked immunosorbent assay, western blot analysis, whole-cell patch-clamp recording, immunofluorescence staining and quantitative real-time PCR. RESULTS In the present study, we found that hind paw injection with CFA induced pain sensitization and anxiety-like behaviors in mice. The expression of GIPR in the ACC was significantly higher in CFA-injected mice. D-Ala2-GIP administration by intraperitoneal or ACC local microinjection produced analgesic and anxiolytic effects; these were blocked by Pro3-GIP and GIPR shRNA knockdown in the ACC. Activation of GIPR inhibited neuroinflammation and activation of microglia, reversed the upregulation of NMDA and AMPA receptors, and suppressed the enhancement of excitatory neurotransmission in the ACC of model mice. CONCLUSIONS GIPR activation was found to produce analgesic and anxiolytic effects, which were partially due to attenuation of neuroinflammation and inhibition of excitatory transmission in the ACC. GIPR may be a suitable target for treatment of chronic inflammatory pain and pain-related anxiety.
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Affiliation(s)
- Xin-shang Wang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, China
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi’an, China
| | - Yong-li Jiang
- Precision Pharmacy and Drug Development Center, Department of Pharmacy, Tangdu Hospital, Fourth Military Medical University, Xi’an, China
| | - Liang Lu
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, China
| | - Ban Feng
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, China
| | - Xue Ma
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, China
| | - Kun Zhang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, China
| | - Shao-yu Guan
- Precision Pharmacy and Drug Development Center, Department of Pharmacy, Tangdu Hospital, Fourth Military Medical University, Xi’an, China
| | - Le Yang
- Precision Pharmacy and Drug Development Center, Department of Pharmacy, Tangdu Hospital, Fourth Military Medical University, Xi’an, China
| | - Qing-yu Fan
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, China
| | - Xiao-chen Zhu
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, China
| | - Fan Yang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, China
| | - Jing-yu Qi
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, China
| | - Liu-kun Yang
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, China
| | - Xu-bo Li
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, China
| | - Ming-gao Zhao
- Precision Pharmacy and Drug Development Center, Department of Pharmacy, Tangdu Hospital, Fourth Military Medical University, Xi’an, China
| | - Wen Jiang
- Department of Neurology, Xijing Hospital, Fourth Military Medical University, Xi’an, China
- *Correspondence: Shui-bing Liu, ; Zhen Tian, ; Wen Jiang,
| | - Zhen Tian
- Precision Pharmacy and Drug Development Center, Department of Pharmacy, Tangdu Hospital, Fourth Military Medical University, Xi’an, China
- Department of Pharmacology, College of Pharmaceutical Sciences, Southwest University, Chongqing, China
- *Correspondence: Shui-bing Liu, ; Zhen Tian, ; Wen Jiang,
| | - Shui-bing Liu
- Department of Pharmacology, School of Pharmacy, Fourth Military Medical University, Xi’an, China
- *Correspondence: Shui-bing Liu, ; Zhen Tian, ; Wen Jiang,
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Yuan L, Zhang J, Guo JH, Holscher C, Yang JT, Wu MN, Wang ZJ, Cai HY, Han LN, Shi H, Han YF, Qi JS. DAla2-GIP-GLU-PAL Protects Against Cognitive Deficits and Pathology in APP/PS1 Mice by Inhibiting Neuroinflammation and Upregulating cAMP/PKA/CREB Signaling Pathways. J Alzheimers Dis 2021; 80:695-713. [PMID: 33579843 DOI: 10.3233/jad-201262] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Abstract
BACKGROUND Alzheimer's disease (AD) is a neurodegenerative disease characterized by progressive decline in cognitive function. Type 2 diabetes mellitus (T2DM) is an important risk factor for AD. Glucose-dependent insulinotropic polypeptide (GIP) has been identified to be effective in T2DM treatment and neuroprotection. OBJECTIVE The present study investigated the neuroprotective effects and possible mechanisms of DAla2GIP-Glu-PAL, a novel long-lasting GIP analogue, in APP/PS1 AD mice. METHODS Multiple behavioral tests were performed to examine the cognitive function of mice. In vivo hippocampus late-phase long-term potentiation (L-LTP) was recorded to reflect synaptic plasticity. Immunohistochemistry and immunofluorescence were used to examine the Aβ plaques and neuroinflammation in the brain. IL-1β, TNF-α, and cAMP/PKA/CREB signal molecules were also detected by ELISA or western blotting. RESULTS DAla2GIP-Glu-PAL increased recognition index (RI) of APP/PS1 mice in novel object recognition test, elevated spontaneous alternation percentage of APP/PS1 mice in Y maze test, and increased target quadrant swimming time of APP/PS1 mice in Morris water maze test. DAla2GIP-Glu-PAL treatment enhanced in vivo L-LTP of APP/PS1 mice. DAla2GIP-Glu-PAL significantly reduced Aβ deposition, inhibited astrocyte and microglia proliferation, and weakened IL-1β and TNF-α secretion. DAla2GIP-Glu-PAL also upregulated cAMP/PKA/CREB signal transduction and inhibited NF-κB activation in the hippocampus of APP/PS1 mice. CONCLUSION DAla2GIP-Glu-PAL can improve cognitive behavior, synaptic plasticity, and central pathological damage in APP/PS1 mice, which might be associated with the inhibition of neuroinflammation, as well as upregulation of cAMP-/PKA/CREB signaling pathway. This study suggests a potential benefit of DAla2GIP-Glu-PAL in the treatment of AD.
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Affiliation(s)
- Li Yuan
- Department of Physiology, Changzhi Medical College, Changzhi, Shanxi, PR China.,Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi, PR China
| | - Jun Zhang
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi, PR China
| | - Jun-Hong Guo
- Department of Neurology, First Hospital, Shanxi Medical University, Taiyuan, Shanxi, PR China
| | - Christian Holscher
- Research and Experimental Center, Henan University of Chinese Medicine, Zhengzhou, Henan, PR China
| | - Jun-Ting Yang
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi, PR China
| | - Mei-Na Wu
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi, PR China
| | - Zhao-Jun Wang
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi, PR China
| | - Hong-Yan Cai
- Department of Immunology and Microbiology, Shanxi Medical University, Taiyuan, Shanxi, PR China
| | - Ling-Na Han
- Department of Physiology, Changzhi Medical College, Changzhi, Shanxi, PR China
| | - Hui Shi
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi, PR China
| | - Yu-Fei Han
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi, PR China
| | - Jin-Shun Qi
- Department of Physiology, Key Laboratory of Cellular Physiology, Ministry of Education, Shanxi Medical University, Taiyuan, Shanxi, PR China
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Rojas M, Chávez-Castillo M, Bautista J, Ortega Á, Nava M, Salazar J, Díaz-Camargo E, Medina O, Rojas-Quintero J, Bermúdez V. Alzheimer’s disease and type 2 diabetes mellitus: Pathophysiologic and pharmacotherapeutics links. World J Diabetes 2021; 12:745-766. [PMID: 34168725 PMCID: PMC8192246 DOI: 10.4239/wjd.v12.i6.745] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 03/20/2021] [Accepted: 05/21/2021] [Indexed: 02/06/2023] Open
Abstract
At present, Alzheimer’s disease (AD) and type 2 diabetes mellitus (T2DM) are two highly prevalent disorders worldwide, especially among elderly individuals. T2DM appears to be associated with cognitive dysfunction, with a higher risk of developing neurocognitive disorders, including AD. These diseases have been observed to share various pathophysiological mechanisms, including alterations in insulin signaling, defects in glucose transporters (GLUTs), and mitochondrial dysfunctions in the brain. Therefore, the aim of this review is to summarize the current knowledge regarding the molecular mechanisms implicated in the association of these pathologies as well as recent therapeutic alternatives. In this context, the hyperphosphorylation of tau and the formation of neurofibrillary tangles have been associated with the dysfunction of the phosphatidylinositol 3-kinase and mitogen-activated protein kinase pathways in the nervous tissues as well as the decrease in the expression of GLUT-1 and GLUT-3 in the different areas of the brain, increase in reactive oxygen species, and production of mitochondrial alterations that occur in T2DM. These findings have contributed to the implementation of overlapping pharmacological interventions based on the use of insulin and antidiabetic drugs, or, more recently, azeliragon, amylin, among others, which have shown possible beneficial effects in diabetic patients diagnosed with AD.
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Affiliation(s)
- Milagros Rojas
- Endocrine and Metabolic Diseases Research Center, School of Medicine, University of Zulia, Maracaibo 4004, Venezuela
| | - Mervin Chávez-Castillo
- Endocrine and Metabolic Diseases Research Center, School of Medicine, University of Zulia, Maracaibo 4004, Venezuela
| | - Jordan Bautista
- Endocrine and Metabolic Diseases Research Center, School of Medicine, University of Zulia, Maracaibo 4004, Venezuela
| | - Ángel Ortega
- Endocrine and Metabolic Diseases Research Center, School of Medicine, University of Zulia, Maracaibo 4004, Venezuela
| | - Manuel Nava
- Endocrine and Metabolic Diseases Research Center, School of Medicine, University of Zulia, Maracaibo 4004, Venezuela
| | - Juan Salazar
- Endocrine and Metabolic Diseases Research Center, School of Medicine, University of Zulia, Maracaibo 4004, Venezuela
| | - Edgar Díaz-Camargo
- Universidad Simón Bolívar, Facultad de Ciencias Jurídicas y Sociales, Cúcuta 540006, Colombia
| | - Oscar Medina
- Universidad Simón Bolívar, Facultad de Ciencias Jurídicas y Sociales, Cúcuta 540006, Colombia
| | - Joselyn Rojas-Quintero
- Pulmonary and Critical Care Medicine Department, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02155, United States
| | - Valmore Bermúdez
- Universidad Simón Bolívar, Facultad de Ciencias de la Salud, Barranquilla 080001, Colombia
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Targeting impaired nutrient sensing with repurposed therapeutics to prevent or treat age-related cognitive decline and dementia: A systematic review. Ageing Res Rev 2021; 67:101302. [PMID: 33609776 DOI: 10.1016/j.arr.2021.101302] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2020] [Revised: 02/13/2021] [Accepted: 02/15/2021] [Indexed: 12/13/2022]
Abstract
BACKGROUND Dementia is a debilitating syndrome that significantly impacts individuals over the age of 65 years. There are currently no disease-modifying treatments for dementia. Impairment of nutrient sensing pathways has been implicated in the pathogenesis of dementia, and may offer a novel treatment approach for dementia. AIMS This systematic review collates all available evidence for Food and Drug Administration (FDA)-approved therapeutics that modify nutrient sensing in the context of preventing cognitive decline or improving cognition in ageing, mild cognitive impairment (MCI), and dementia populations. METHODS PubMed, Embase and Web of Science databases were searched using key search terms focusing on available therapeutics such as 'metformin', 'GLP1', 'insulin' and the dementias including 'Alzheimer's disease' and 'Parkinson's disease'. Articles were screened using Covidence systematic review software (Veritas Health Innovation, Melbourne, Australia). The risk of bias was assessed using the Cochrane Risk of Bias tool v 2.0 for human studies and SYRCLE's risk of bias tool for animal studies. RESULTS Out of 2619 articles, 114 were included describing 31 different 'modulation of nutrient sensing pathway' therapeutics, 13 of which specifically were utilized in human interventional trials for normal ageing or dementia. Growth hormone secretagogues improved cognitive outcomes in human mild cognitive impairment, and potentially normal ageing populations. In animals, all investigated therapeutic classes exhibited some cognitive benefits in dementia models. While the risk of bias was relatively low in human studies, this risk in animal studies was largely unclear. CONCLUSIONS Modulation of nutrient sensing pathway therapeutics, particularly growth hormone secretagogues, have the potential to improve cognitive outcomes. Overall, there is a clear lack of translation from animal models to human populations.
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Bonfili L, Cecarini V, Gogoi O, Gong C, Cuccioloni M, Angeletti M, Rossi G, Eleuteri AM. Microbiota modulation as preventative and therapeutic approach in Alzheimer's disease. FEBS J 2020; 288:2836-2855. [PMID: 32969566 DOI: 10.1111/febs.15571] [Citation(s) in RCA: 53] [Impact Index Per Article: 13.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 08/27/2020] [Accepted: 09/17/2020] [Indexed: 12/23/2022]
Abstract
The gut microbiota coevolves with its host, and numerous factors like diet, lifestyle, drug intake and geographical location continuously modify its composition, deeply influencing host health. Recent studies demonstrated that gut dysbiosis can alter normal brain function through the so-called gut-brain axis, a bidirectional communication network between the central nervous system and the gastrointestinal tract, thus playing a key role in the pathogenesis of neurodegenerative disorders, such as Alzheimer's disease (AD). In this perspective, in the constant search for novel treatments in AD, the rational modulation of gut microbiota composition could represent a promising approach to prevent or delay AD onset or to counteract its progression. Preclinical and human studies on microbiota modulation through oral bacteriotherapy and faecal transplantation showed anti-inflammatory and antioxidant effects, upregulation of plasma concentration of neuroprotective hormones, restoration of impaired proteolytic pathways, amelioration of energy homeostasis with consequent decrease of AD molecular hallmarks and improvement of behavioural and cognitive performances. In this review, we dissect the role of gut microbiota in AD and highlight recent advances in the development of new multitarget strategies for microbiota modulation to be used as possible preventative and therapeutic approaches in AD.
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Affiliation(s)
- Laura Bonfili
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Valentina Cecarini
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Olee Gogoi
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Chunmei Gong
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | | | - Mauro Angeletti
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Giacomo Rossi
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
| | - Anna Maria Eleuteri
- School of Biosciences and Veterinary Medicine, University of Camerino, Camerino, Italy
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Salameh TS, Rhea EM, Talbot K, Banks WA. Brain uptake pharmacokinetics of incretin receptor agonists showing promise as Alzheimer's and Parkinson's disease therapeutics. Biochem Pharmacol 2020; 180:114187. [PMID: 32755557 PMCID: PMC7606641 DOI: 10.1016/j.bcp.2020.114187] [Citation(s) in RCA: 65] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2020] [Revised: 07/29/2020] [Accepted: 07/30/2020] [Indexed: 12/15/2022]
Abstract
Among the more promising treatments proposed for Alzheimer's disease (AD) and Parkinson's disease (PD) are those reducing brain insulin resistance. The antidiabetics in the class of incretin receptor agonists (IRAs) reduce symptoms and brain pathology in animal models of AD and PD, as well as glucose utilization in AD cases and clinical symptoms in PD cases after their systemic administration. At least 9 different IRAs are showing promise as AD and PD therapeutics, but we still lack quantitative data on their relative ability to cross the blood-brain barrier (BBB) reaching the brain parenchyma. We consequently compared brain uptake pharmacokinetics of intravenous 125I-labeled IRAs in adult CD-1 mice over the course of 60 min. We tested single IRAs (exendin-4, liraglutide, lixisenatide, and semaglutide), which bind receptors for one incretin (glucagon-like peptide-1 [GLP-1]), and dual IRAs, which bind receptors for two incretins (GLP-1 and glucose-dependent insulinotropic polypeptide [GIP]), including unbranched, acylated, PEGylated, or C-terminally modified forms (Finan/Ma Peptides 17, 18, and 20 and Hölscher peptides DA3-CH and DA-JC4). The non-acylated and non-PEGylated IRAs (exendin-4, lixisenatide, Peptide 17, DA3-CH and DA-JC4) had significant rates of blood-to-brain influx (Ki), but the acylated IRAs (liraglutide, semaglutide, and Peptide 18) did not measurably cross the BBB. The brain influx of the non-acylated, non-PEGylated IRAs were not saturable up to 1 μg of these drugs and was most likely mediated by adsorptive transcytosis across brain endothelial cells, as observed for exendin-4. Of the non-acylated, non-PEGylated IRAs tested, exendin-4 and DA-JC4 were best able to cross the BBB based on their rate of brain influx, percentage reaching the brain that accumulated in brain parenchyma, and percentage of the systemic dose taken up per gram of brain tissue. Exendin-4 and DA-JC4 thus merit special attention as IRAs well-suited to enter the central nervous system (CNS), thus reaching areas pathologic in AD and PD.
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Affiliation(s)
- Therese S Salameh
- Veterans Affairs Puget Sound Health Care System, Geriatrics Research Education and Clinical Center, Seattle, WA 98108, USA; University of Washington School of Medicine, Division of Gerontology and Geriatric Medicine, Department of Medicine, Seattle, WA 98498, USA
| | - Elizabeth M Rhea
- Veterans Affairs Puget Sound Health Care System, Geriatrics Research Education and Clinical Center, Seattle, WA 98108, USA; University of Washington School of Medicine, Division of Gerontology and Geriatric Medicine, Department of Medicine, Seattle, WA 98498, USA
| | - Konrad Talbot
- Loma Linda University School of Medicine, Departments of Neurosurgery, Basic Sciences, and Pathology and Human Anatomy, Loma Linda, CA 92354, USA
| | - William A Banks
- Veterans Affairs Puget Sound Health Care System, Geriatrics Research Education and Clinical Center, Seattle, WA 98108, USA; University of Washington School of Medicine, Division of Gerontology and Geriatric Medicine, Department of Medicine, Seattle, WA 98498, USA.
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10
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Madhusudhanan J, Suresh G, Devanathan V. Neurodegeneration in type 2 diabetes: Alzheimer's as a case study. Brain Behav 2020; 10:e01577. [PMID: 32170854 PMCID: PMC7218246 DOI: 10.1002/brb3.1577] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/17/2019] [Accepted: 01/04/2020] [Indexed: 12/12/2022] Open
Abstract
INTRODUCTION Rigorous research in the last few years has shown that in addition to the classical mechanism of neurodegeneration, certain unconventional mechanisms may also lead to neurodegenerative disease. One of them is a widely studied metabolic disorder: type 2 diabetes mellitus (T2DM). We now have a clear understanding of glucose-mediated neurodegeneration, mostly from studies in Alzheimer's disease (AD) models. AD is recognized to be significantly associated with hyperglycemia, even earning the term "type 3 diabetes." Here, we review first the pathophysiology of AD, both from the perspective of classical protein accumulation, as well as the newer T2DM-dependent mechanisms supported by findings from patients with T2DM. Secondly, we review the different pathways through which neurodegeneration is aggravated in hyperglycemic conditions taking AD as a case study. Finally, some of the current advances in AD management as a result of recent research developments in metabolic disorders-driven neurodegeneration are also discussed. METHODS Relevant literatures found from PubMed search were reviewed. RESULTS Apart from the known causes of AD, type 2 diabetes opens a new window to the AD pathology in several ways. It is a bidirectional interaction, of which, the molecular and signaling mechanisms are recently studied. This is our attempt to connect all of them to draw a complete mechanistic explanation for the neurodegeneration in T2DM. Refer to Figure 3. CONCLUSION The perspective of AD as a classical neurodegenerative disease is changing, and it is now being looked at from a zoomed-out perspective. The correlation between T2DM and AD is something observed and studied extensively. It is promising to know that there are certain advances in AD management following these studies.
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Affiliation(s)
- Jalaja Madhusudhanan
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, India
| | - Gowthaman Suresh
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, India
| | - Vasudharani Devanathan
- Department of Biology, Indian Institute of Science Education and Research (IISER) Tirupati, Tirupati, India
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11
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Zhang ZQ, Hölscher C. GIP has neuroprotective effects in Alzheimer and Parkinson's disease models. Peptides 2020; 125:170184. [PMID: 31705913 DOI: 10.1016/j.peptides.2019.170184] [Citation(s) in RCA: 47] [Impact Index Per Article: 11.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/14/2019] [Revised: 10/28/2019] [Accepted: 10/29/2019] [Indexed: 12/17/2022]
Abstract
Glucose-dependent Insulinotropic polypeptide (GIP) is a peptide hormone of the incretin family. It has growth factor properties and can re-activate energy utilization. In progressive neurodegenerative disorders such as Alzheimer's and Parkinson's disease, energy utilization is much reduced, and GIP has the potential to reverse this. Furthermore, GIP can reduce the inflammation response in the brain and reduce levels of pro-inflammatory cytokines. Tests in animal models of Alzheimer's and Parkinson's disease show good neuroprotective effects. In Parkinson's disease models, motor activity is normalized, dopaminergic neurons are protected, synapse numbers and dopamine levels are maintained. Levels of growth factors that are essential for neuronal and synaptic function are increased and alpha-synuclein levels are reduced. The chronic inflammation response and mitochondrial damage is reduced. In Alzheimer's disease models, memory is rescued, synapse numbers and synaptic plasticity in the hippocampus is normalized, amyloid plaque load and the chronic inflammation is reduced. Similar protective effects have been previously reported with analogues of glucagon-like peptide 1 (GLP-1), the sister incretin hormone. First clinical trials show good protective effects in both diseases. Recently, novel dual GLP-1/GIP receptor agonists have been developed. The ability to cross the blood-brain barrier (BBB) is key to their neuroprotective effects. We have developed two dual GLP-1/GIP receptor agonist that have cell penetrating sequences added for better BBB penetration. In direct comparisons, these dual agonists show improved neuroprotection in a mouse model of Parkinson's disease. Therefore, such novel multiple receptor agonists hold great promise as potential treatments for Alzheimer's and Parkinson's disease.
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Affiliation(s)
- Zhen Qiang Zhang
- Research and Experimental Center, Henan University of Chinese Medicine, Zhengzhou, Henan Province, China
| | - Christian Hölscher
- Research and Experimental Center, Henan University of Chinese Medicine, Zhengzhou, Henan Province, China.
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12
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Adriaenssens AE, Gribble FM, Reimann F. The glucose-dependent insulinotropic polypeptide signaling axis in the central nervous system. Peptides 2020; 125:170194. [PMID: 31697967 DOI: 10.1016/j.peptides.2019.170194] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/31/2019] [Revised: 10/31/2019] [Accepted: 10/31/2019] [Indexed: 12/25/2022]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) is an incretin hormone released from the epithelium of the upper small intestine. While GIP shares common actions on the pancreatic beta cell with glucagon-like peptide-1 (GLP-1), unlike GLP-1, GIP presents a complex target for the development of diabetes and obesity therapies due to its extra-pancreatic effects on fat mass. Recent pharmacological developments, however, have provided insight into a previously unrecognized role for GIP receptor (GIPR) signaling in regulating appetite. Additionally, GIP-based therapeutics have demonstrated promising neuroprotective properties. Together these observations identify an important central component of the GIP/GIPR signaling axis, and have triggered a resurgence of research interest into the central actions of GIP. In this review, we discuss what is currently known about where GIP may act in the central nervous system (CNS), the characteristics of its target cell populations, and the physiological effects of manipulating the activity Gipr-expressing cells in the brain.
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Affiliation(s)
- A E Adriaenssens
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK
| | - F M Gribble
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK.
| | - F Reimann
- Metabolic Research Laboratories, Wellcome Trust MRC Institute of Metabolic Science, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0QQ, UK.
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13
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Zhang CY, Boylan MO, Arakawa H, Wolfe MM. Effects of gastric inhibitory polypeptide (GIP) immunoneutralization on mouse motor coordination and memory. Peptides 2020; 125:170227. [PMID: 31805296 DOI: 10.1016/j.peptides.2019.170227] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/28/2019] [Revised: 11/27/2019] [Accepted: 11/29/2019] [Indexed: 11/20/2022]
Abstract
Gastric inhibitory polypeptide (GIP) is a regulatory peptide expressed in the mammalian upper small intestine, and both GIP and its receptor (GIPR) are expressed in the cortex and hippocampus regions of the brain as well. While learning and memory deficits have been observed in GIPR-/- mice, the effects of peripheral GIP immunoneutralization on motor-coordination, learning, and memory have not been examined. In the present study, adult GIPR-/- mice (KO) and age-matched wild-type C57BL/6 J mice (WT) received weekly vehicle PBS injections for 12 weeks, while a third group of wild-type mice were injected weekly for 12 weeks with 30 mg/kg body weight humanized GIP-mAb (AB) to assess the possibility of long-term effects of peripheral GIP antagonism on rodent memory and behavior. All mice groups then underwent a battery of tests that evaluated motor behavior, body coordination, and memory. Performance deficits in several memory studies after 12 weeks of treatment were demonstrated in KO, but not in AB or WT mice. Body coordination performance showed no significant differences among the 3 groups. A similar short-term study (3 injections over 9 days) was also conducted and the results were similar to those from the long-term study. Thus, short-term and long-term peripheral GIP antagonism by GIP-mAb did not appear to affect learning and memory in mice, consistent with the notion that the GIP-mAb does not cross the blood brain barrier. Furthermore, our studies indicate that GIP signaling in the brain appears to involve local neurocrine pathways.
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Affiliation(s)
- Claire Y Zhang
- Division of Gastroenterology, MetroHealth Medical Center, Case Western Reserve University, Cleveland, OH, United States
| | - Michael O Boylan
- Division of Gastroenterology, MetroHealth Medical Center, Case Western Reserve University, Cleveland, OH, United States
| | - Hiroyuki Arakawa
- Department of Neuroscience, Case Western Reserve University, Cleveland, OH, United States
| | - M Michael Wolfe
- Division of Gastroenterology, MetroHealth Medical Center, Case Western Reserve University, Cleveland, OH, United States; Department of Physiology and Biophysics, Case Western Reserve University, Cleveland, OH, United States.
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14
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GIP as a Potential Therapeutic Target for Atherosclerotic Cardiovascular Disease-A Systematic Review. Int J Mol Sci 2020; 21:ijms21041509. [PMID: 32098413 PMCID: PMC7073149 DOI: 10.3390/ijms21041509] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 02/20/2020] [Accepted: 02/21/2020] [Indexed: 02/06/2023] Open
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are gut hormones that are secreted from enteroendocrine L cells and K cells in response to digested nutrients, respectively. They are also referred to incretin for their ability to stimulate insulin secretion from pancreatic beta cells in a glucose-dependent manner. Furthermore, GLP-1 exerts anorexic effects via its actions in the central nervous system. Since native incretin is rapidly inactivated by dipeptidyl peptidase-4 (DPP-4), DPP-resistant GLP-1 receptor agonists (GLP-1RAs), and DPP-4 inhibitors are currently used for the treatment of type 2 diabetes as incretin-based therapy. These new-class agents have superiority to classical oral hypoglycemic agents such as sulfonylureas because of their low risks for hypoglycemia and body weight gain. In addition, a number of preclinical studies have shown the cardioprotective properties of incretin-based therapy, whose findings are further supported by several randomized clinical trials. Indeed, GLP-1RA has been significantly shown to reduce the risk of cardiovascular and renal events in patients with type 2 diabetes. However, the role of GIP in cardiovascular disease remains to be elucidated. Recently, pharmacological doses of GIP receptor agonists (GIPRAs) have been found to exert anti-obesity effects in animal models. These observations suggest that combination therapy of GLP-1R and GIPR may induce superior metabolic and anti-diabetic effects compared with each agonist individually. Clinical trials with GLP-1R/GIPR dual agonists are ongoing in diabetic patients. Therefore, in this review, we summarize the cardiovascular effects of GIP and GIPRAs in cell culture systems, animal models, and humans.
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15
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Guo R, Sun Y, Li H, Ma D, Wang Y. Upregulation of spinal glucose-dependent insulinotropic polypeptide receptor induces membrane translocation of PKCγ and synaptic target of AMPA receptor GluR1 subunits in dorsal horns in a rat model of incisional pain. Neurochem Int 2019; 134:104651. [PMID: 31870892 DOI: 10.1016/j.neuint.2019.104651] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2019] [Revised: 12/16/2019] [Accepted: 12/19/2019] [Indexed: 01/28/2023]
Abstract
It is unclear whether glucose-dependent insulinotropic polypeptide receptor (GIPR) signaling plays an important role in spinal nociception. We hypothesized that the spinal GIPR is implicated in central sensitization of postoperative pain. Our data showed that the cumulative pain scores peaked at 3 h, kept at a high level at 1 d after incision, gradually decreased afterwards and returned to the baseline values at 5 d after incision. Correspondingly, the expression of GIPR in spinal cord dorsal horn peaked at 1 d after incision, and returned to the baseline value at 5 d after incision. The double-labeling immunofluorescence demonstrated that spinal GIPR was expressed in dorsal horn neurons, but not in astrocyte or microglial cells. At 1 d after incision, the effects of intrathecal saline, GIPR antagonist (Pro3)GIP on pain behaviors were investigated. Our data showed that at 30 min and 60 min following intrathecal treatments of 300 ng (Pro3)GIP, the cumulative pain scores were decreased and paw withdrawal thresholds to mechanical stimuli were increased when compared to those immediately before intrathecal treatments. Accordingly, at 30 min after intrathecal injections, the membrane translocation levels of PKCγ and the GluR1 expression in postsynaptic membrane in ipsilateral dorsal horns to the incision were significantly upregulated in rats with intrathecal saline injections, as compared to normal control group. At 30 min after intrathecal treatment, (Pro3)GIP inhibited the membrane translocation levels of PKCγ and the GluR1 expression in postsynaptic membrane in ipsilateral dorsal horns. Our study indicates that upregulation of spinal GIPR may contribute to pain hypersensitivity through inducing membrane translocation level of PKCγ and synaptic target of AMPA receptor GluR1 subunits in ipsilateral dorsal horns of rats with plantar incision.
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Affiliation(s)
- Ruijuan Guo
- Department of Anesthesiology, Beijing Friendship Hospital, Capital Medical University, Beijing, 100050, China
| | - Yuqing Sun
- Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020, China
| | - Huili Li
- Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020, China
| | - Danxu Ma
- Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020, China
| | - Yun Wang
- Department of Anesthesiology, Beijing Chaoyang Hospital, Capital Medical University, Beijing, 100020, China.
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16
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Farr OM, Pilitsi E, Mantzoros CS. Of mice and men: incretin actions in the central nervous system. Metabolism 2019; 98:121-135. [PMID: 31173757 DOI: 10.1016/j.metabol.2019.05.013] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/18/2019] [Revised: 05/30/2019] [Accepted: 05/31/2019] [Indexed: 02/06/2023]
Abstract
Incretins have risen to the forefront of therapies for obesity and related metabolic complications, primarily because of their efficacy and relatively few side effects. Importantly, their efficacy in altering energy balance and decreasing body weight is apparently through actions in the central nervous system (CNS); the latter may have implications beyond obesity per se, i.e. in other disease states associated with obesity including CNS-related disorders. Here, we first describe the role of the CNS in energy homeostasis and then the current state of knowledge in terms of incretin physiology, pathophysiology and efficacy in preclinical and clinical studies. In the future, more clinical studies are needed to fully map mechanistic pathways underlying incretin actions and outcomes in the human CNS. Additionally, future research will likely lead to the discovery of additional novel incretins and/or more efficacious medications with less side effects through the improvement of current compounds with properties that would allow them to have more favorable pharmacokinetic and pharmacodynamic profiles and/or by combining known and novel incretins into safe and more efficacious combination therapies leading ultimately to more tangible benefits for our patients.
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Affiliation(s)
- Olivia M Farr
- Division of Endocrinology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA 02215, United States of America.
| | - Eleni Pilitsi
- Division of Endocrinology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA 02215, United States of America
| | - Christos S Mantzoros
- Division of Endocrinology, Beth Israel Deaconess Medical Center/Harvard Medical School, Boston, MA 02215, United States of America; Section of Endocrinology, VA Boston Healthcare System, Boston, MA 02130, United States of America
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17
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Khalilnezhad A, Taskiran D. The investigation of protective effects of glucagon-like peptide-1 (GLP-1) analogue exenatide against glucose and fructose-induced neurotoxicity. Int J Neurosci 2019; 129:481-491. [PMID: 30422728 DOI: 10.1080/00207454.2018.1543671] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
Diabetes mellitus (DM) is one of the most common metabolic disorders characterized by hyperglycemia due to insufficiency of insulin and/or insulin resistance. Clinical studies have revealed a higher risk of neurodegenerative disorders such as Alzheimer's disease or Parkinson's disease in diabetic patients. Recently, glucagon-like peptide-1 (GLP-1) is an attractive potential treatment modality for various neurodegenerative diseases. In our study, we aimed to investigate whether exenatide, a GLP-1 analogue, has neuroprotective effects against glucose and fructose-induced toxicity in human SH-SY5Y neuroblastoma cell line. Neurotoxicity was induced by incubating SH-SY5Y cells with different doses (25-100 mM) of glucose and fructose for 24, 48 and 72 hours. Following determination of the significant toxic doses of glucose and fructose, the cells were treated with various doses of exenatide (10-250 nM) in the presence or absence of glucose and fructose. Neurotoxicity was evaluated by MTT assay and Hoechst 33258 staining. Caspase-3 activity and the levels of advanced glycation end products (AGEs) were determined in the cytosolic fractions of treated cells. Our results demonstrated that both glucose and fructose treatments decreased cell viability in neuronal cells dose and time-dependently. Glucose and fructose-treated groups showed increased numbers of apoptotic cells, caspase-3 activity and AGEs levels. Treatment of the cells with exenatide significantly prevented cell death. The most prominent effect was observed at 100 nM exenatide-treated cultures. Our results suggest that high doses of glucose and fructose may lead to neurotoxicity, and exenatide may have protective effects against neuronal damage through its anti-apoptotic feature.
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Affiliation(s)
- Asghar Khalilnezhad
- a Department of Physiology, Ege University School of Medicine , Izmir , Turkey
| | - Dilek Taskiran
- a Department of Physiology, Ege University School of Medicine , Izmir , Turkey
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18
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Hölscher C. Insulin Signaling Impairment in the Brain as a Risk Factor in Alzheimer's Disease. Front Aging Neurosci 2019; 11:88. [PMID: 31068799 PMCID: PMC6491455 DOI: 10.3389/fnagi.2019.00088] [Citation(s) in RCA: 64] [Impact Index Per Article: 12.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/02/2019] [Accepted: 04/03/2019] [Indexed: 12/14/2022] Open
Abstract
Type 2 diabetes is a risk factor for developing Alzheimer’s disease (AD). The underlying mechanism that links up the two conditions seems to be the de-sensitization of insulin signaling. In patients with AD, insulin signaling was found to be de-sensitized in the brain, even if they did not have diabetes. Insulin is an important growth factor that regulates cell growth, energy utilization, mitochondrial function and replacement, autophagy, oxidative stress management, synaptic plasticity, and cognitive function. Insulin desensitization, therefore, can enhance the risk of developing neurological disorders in later life. Other risk factors, such as high blood pressure or brain injury, also enhance the likelihood of developing AD. All these risk factors have one thing in common – they induce a chronic inflammation response in the brain. Pro-inflammatory cytokines block growth factor signaling and enhance oxidative stress. The underlying molecular processes for this are described in the review. Treatments to re-sensitize insulin signaling in the brain are also described, such as nasal insulin tests in AD patients, or treatments with re-sensitizing hormones, such as leptin, ghrelin, glucagon-like peptide 1 (GLP-1),and glucose-dependent insulinotropic polypeptide (GIP). The first clinical trials show promising results and are a proof of concept that utilizing such treatments is valid.
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Affiliation(s)
- Christian Hölscher
- Research and Experimental Center, Henan University of Chinese Medicine, Zhengzhou, China
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Verma MK, Goel R, Krishnadas N, Nemmani KVS. Targeting glucose-dependent insulinotropic polypeptide receptor for neurodegenerative disorders. Expert Opin Ther Targets 2018; 22:615-628. [PMID: 29911915 DOI: 10.1080/14728222.2018.1487952] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
INTRODUCTION Incretin hormones, glucose-dependent insulinotropic polypeptide (GIP), and glucagon-like peptide-1 (GLP-1) exert pleiotropic effects on endocrine pancreas and nervous system. Expression of GIP and GIP receptor (GIPR) in neurons, their roles in neurogenesis, synaptic plasticity, neurotransmission, and neuromodulation uniquely position GIPR for therapeutic applications in neurodegenerative disorders. GIP analogs acting as GIPR agonists attenuate neurobehavioral and neuropathological sequelae of neurodegenerative disorders in preclinical models, e.g. Alzheimer's disease (AD), Parkinson's disease (PD), and cerebrovascular disorders. Modulation of GIPR signaling offers an unprecedented approach for disease modification by arresting neuronal viability decline, enabling neuronal regeneration, and reducing neuroinflammation. Growth-promoting effects of GIP signaling and broad-based neuroprotection highlight the therapeutic potential of GIPR agonists. Areas covered: This review focuses on the role of GIPR-mediated signaling in the central nervous system in neurophysiological and neuropathological conditions. In context of neurodegeneration, the article summarizes potential of targeting GIPR signaling for neurodegenerative conditions such as AD, PD, traumatic brain injury, and cerebrovascular disorders. Expert opinion: GIPR represents a validated therapeutic target for neurodegenerative disorders. GIPR agonists impart symptomatic improvements, slowed neurodegeneration, and enhanced neuronal regenerative capacity in preclinical models. Modulation of GIPR signaling is potentially a viable therapeutic approach for disease modification in neurodegenerative disorders.
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Affiliation(s)
- Mahip K Verma
- a Department of Pharmacology, Novel Drug Discovery and Development , Lupin Limited , Pune , India
| | - Rajan Goel
- a Department of Pharmacology, Novel Drug Discovery and Development , Lupin Limited , Pune , India
| | - Nandakumar Krishnadas
- b Department of Pharmacology , Manipal College of Pharmaceutical Sciences, Manipal Academy of Higher Education (MAHE) , Manipal , India
| | - Kumar V S Nemmani
- a Department of Pharmacology, Novel Drug Discovery and Development , Lupin Limited , Pune , India
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Glucose-Dependent Insulinotropic Polypeptide Mitigates 6-OHDA-Induced Behavioral Impairments in Parkinsonian Rats. Int J Mol Sci 2018; 19:ijms19041153. [PMID: 29641447 PMCID: PMC5979480 DOI: 10.3390/ijms19041153] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/12/2018] [Revised: 04/04/2018] [Accepted: 04/06/2018] [Indexed: 12/22/2022] Open
Abstract
In the present study, the effectiveness of glucose-dependent insulinotropic polypeptide (GIP) was evaluated by behavioral tests in 6-hydroxydopamine (6-OHDA) hemi-parkinsonian (PD) rats. Pharmacokinetic measurements of GIP were carried out at the same dose studied behaviorally, as well as at a lower dose used previously. GIP was delivered by subcutaneous administration (s.c.) using implanted ALZET micro-osmotic pumps. After two days of pre-treatment, male Sprague Dawley rats received a single unilateral injection of 6-OHDA into the medial forebrain bundle (MFB). The neuroprotective effects of GIP were evaluated by apomorphine-induced contralateral rotations, as well as by locomotor and anxiety-like behaviors in open-field tests. Concentrations of human active and total GIP were measured in plasma during a five-day treatment period by ELISA and were found to be within a clinically translatable range. GIP pretreatment reduced behavioral abnormalities induced by the unilateral nigrostriatal dopamine (DA) lesion produced by 6-OHDA, and thus may be a novel target for PD therapeutic development.
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21
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Brandt SJ, Götz A, Tschöp MH, Müller TD. Gut hormone polyagonists for the treatment of type 2 diabetes. Peptides 2018; 100:190-201. [PMID: 29412819 PMCID: PMC5805859 DOI: 10.1016/j.peptides.2017.12.021] [Citation(s) in RCA: 62] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/30/2017] [Revised: 12/21/2017] [Accepted: 12/21/2017] [Indexed: 12/20/2022]
Abstract
Chemical derivatives of the gut-derived peptide hormone glucagon-like peptide 1 (GLP-1) are among the best-in-class pharmacotherapies to treat obesity and type 2 diabetes. However, GLP-1 analogs have modest weight lowering capacity, in the range of 5-10%, and the therapeutic window is hampered by dose-dependent side effects. Over the last few years, a new concept has emerged: combining the beneficial effects of several key metabolic hormones into a single molecular entity. Several unimolecular GLP-1-based polyagonists have shown superior metabolic action compared to GLP-1 monotherapies. In this review article, we highlight the history of polyagonists targeting the receptors for GLP-1, GIP and glucagon, and discuss recent progress in expanding of this concept to now allow targeted delivery of nuclear hormones via GLP-1 and other gut hormones, as a novel approach towards more personalized pharmacotherapies.
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Affiliation(s)
- Sara J Brandt
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Business Campus Garching, Parkring 13, 85748 Garching, Germany
| | - Anna Götz
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Business Campus Garching, Parkring 13, 85748 Garching, Germany; Department of Internal Medicine I, University Hospital RWTH Aachen, Aachen, Germany; Institute for Diabetes und Regeneration, Helmholtz Diabetes Center, Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Business Campus Garching, Parkring 13, 85748, Garching, Germany
| | - Matthias H Tschöp
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Business Campus Garching, Parkring 13, 85748 Garching, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany; Division of Metabolic Diseases, Department of Medicine, Technische Universität München, Munich, Germany
| | - Timo D Müller
- Institute for Diabetes and Obesity, Helmholtz Diabetes Center at Helmholtz Zentrum München, German Research Center for Environmental Health (GmbH), Business Campus Garching, Parkring 13, 85748 Garching, Germany; German Center for Diabetes Research (DZD), Neuherberg, Germany.
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Novel dual GLP-1/GIP receptor agonists show neuroprotective effects in Alzheimer's and Parkinson's disease models. Neuropharmacology 2018; 136:251-259. [PMID: 29402504 DOI: 10.1016/j.neuropharm.2018.01.040] [Citation(s) in RCA: 113] [Impact Index Per Article: 18.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2017] [Revised: 01/10/2018] [Accepted: 01/27/2018] [Indexed: 02/06/2023]
Abstract
Type 2 diabetes is a risk factor for several chronic neurodegenerative disorders such as Alzheimer's or Parkinson's disease. The link appears to be insulin de-sensitisation in the brain. Insulin is an important neuroprotective growth factor. GLP-1 and GIP are growth factors that re-sensitise insulin and GLP-1 mimetics are used in the clinic to treat diabetes. GLP-1 and GIP mimetics initially designed to treat diabetes show good protective effects in animal models of Alzheimer's and Parkinson's disease. Based on these results, several clinical trials have shown first encouraging effects in patients with Alzheimer's or Parkinson' disease. Novel dual GLP-1/GIP receptor agonists have been developed to treat diabetes, and they also show good neuroprotective effects that are superior to single GLP-1 analogues. Several newer dual analogues have been tested that have been engineered to cross the blood -brain barrier. They show clear neuroprotective effects by reducing inflammation and oxidative stress and apoptotic signalling and protecting memory formation, synaptic numbers and synaptic activity, motor activity, dopaminergic neurons, cortical activity and energy utilisation in the brain. These results demonstrate the potential of developing disease-modifying treatments for Alzheimer's and Parkinson's disease that are superior to current single GLP-1 mimetics. This article is part of the Special Issue entitled 'Metabolic Impairment as Risk Factors for Neurodegenerative Disorders.'
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23
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Li Y, Li L, Hölscher C. Incretin-based therapy for type 2 diabetes mellitus is promising for treating neurodegenerative diseases. Rev Neurosci 2018; 27:689-711. [PMID: 27276528 DOI: 10.1515/revneuro-2016-0018] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/11/2016] [Accepted: 05/02/2016] [Indexed: 12/13/2022]
Abstract
Incretin hormones include glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). Due to their promising action on insulinotropic secretion and improving insulin resistance (IR), incretin-based therapies have become a new class of antidiabetic agents for the treatment of type 2 diabetes mellitus (T2DM). Recently, the links between neurodegenerative diseases and T2DM have been identified in a number of studies, which suggested that shared mechanisms, such as insulin dysregulation or IR, may underlie these conditions. Therefore, the effects of incretins in neurodegenerative diseases have been extensively investigated. Protease-resistant long-lasting GLP-1 mimetics such as lixisenatide, liraglutide, and exenatide not only have demonstrated promising effects for treating neurodegenerative diseases in preclinical studies but also have shown first positive results in Alzheimer's disease (AD) and Parkinson's disease (PD) patients in clinical trials. Furthermore, the effects of other related incretin-based therapies such as GIP agonists, dipeptidyl peptidase-IV (DPP-IV) inhibitors, oxyntomodulin (OXM), dual GLP-1/GIP, and triple GLP-1/GIP/glucagon receptor agonists on neurodegenerative diseases have been tested in preclinical studies. Incretin-based therapies are a promising approach for treating neurodegenerative diseases.
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24
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Neuroprotective effects of a triple GLP-1/GIP/glucagon receptor agonist in the APP/PS1 transgenic mouse model of Alzheimer's disease. Brain Res 2018; 1678:64-74. [DOI: 10.1016/j.brainres.2017.10.012] [Citation(s) in RCA: 85] [Impact Index Per Article: 14.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2017] [Revised: 10/07/2017] [Accepted: 10/11/2017] [Indexed: 12/13/2022]
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25
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Pitt J, Wilcox KC, Tortelli V, Diniz LP, Oliveira MS, Dobbins C, Yu XW, Nandamuri S, Gomes FCA, DiNunno N, Viola KL, De Felice FG, Ferreira ST, Klein WL. Neuroprotective astrocyte-derived insulin/insulin-like growth factor 1 stimulates endocytic processing and extracellular release of neuron-bound Aβ oligomers. Mol Biol Cell 2017; 28:2623-2636. [PMID: 28963439 PMCID: PMC5620371 DOI: 10.1091/mbc.e17-06-0416] [Citation(s) in RCA: 64] [Impact Index Per Article: 9.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/21/2017] [Accepted: 07/31/2017] [Indexed: 12/19/2022] Open
Abstract
Synaptopathy underlying memory deficits in Alzheimer's disease (AD) is increasingly thought to be instigated by toxic oligomers of the amyloid beta peptide (AβOs). Given the long latency and incomplete penetrance of AD dementia with respect to Aβ pathology, we hypothesized that factors present in the CNS may physiologically protect neurons from the deleterious impact of AβOs. Here we employed physically separated neuron-astrocyte cocultures to investigate potential non-cell autonomous neuroprotective factors influencing AβO toxicity. Neurons cultivated in the absence of an astrocyte feeder layer showed abundant AβO binding to dendritic processes and associated synapse deterioration. In contrast, neurons in the presence of astrocytes showed markedly reduced AβO binding and synaptopathy. Results identified the protective factors released by astrocytes as insulin and insulin-like growth factor-1 (IGF1). The protective mechanism involved release of newly bound AβOs into the extracellular medium dependent upon trafficking that was sensitive to exosome pathway inhibitors. Delaying insulin treatment led to AβO binding that was no longer releasable. The neuroprotective potential of astrocytes was itself sensitive to chronic AβO exposure, which reduced insulin/IGF1 expression. Our findings support the idea that physiological protection against synaptotoxic AβOs can be mediated by astrocyte-derived insulin/IGF1, but that this protection itself is vulnerable to AβO buildup.
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Affiliation(s)
- Jason Pitt
- Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL 60208.,Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Kyle C Wilcox
- Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL 60208
| | - Vanessa Tortelli
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro RJ 21944-590, Brazil
| | - Luan Pereira Diniz
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro RJ 21944-590, Brazil
| | - Maira S Oliveira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro RJ 21944-590, Brazil
| | - Cassandra Dobbins
- Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL 60208
| | - Xiao-Wen Yu
- Department of Physiology, Feinberg School of Medicine, Northwestern University, Chicago, IL 60611
| | - Sathwik Nandamuri
- Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL 60208
| | - Flávia C A Gomes
- Institute of Biomedical Sciences, Federal University of Rio de Janeiro, Rio de Janeiro RJ 21944-590, Brazil
| | - Nadia DiNunno
- Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL 60208
| | - Kirsten L Viola
- Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL 60208
| | - Fernanda G De Felice
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro RJ 21944-590, Brazil.,Centre for Neuroscience Studies, Department of Biomedical and Molecular Sciences, Queen's University, Kingston, ON K7L 3N6, Canada
| | - Sergio T Ferreira
- Institute of Medical Biochemistry Leopoldo de Meis, Federal University of Rio de Janeiro, Rio de Janeiro RJ 21944-590, Brazil.,Institute of Biophysics Carlos Chagas Filho, Federal University of Rio de Janeiro, Rio de Janeiro RJ 21944-590, Brazil
| | - William L Klein
- Department of Neurobiology, Weinberg College of Arts and Sciences, Northwestern University, Evanston, IL 60208
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26
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Verma MK, Goel R, Nandakumar K, Nemmani KV. Effect of D-Ala 2 GIP, a stable GIP receptor agonist on MPTP-induced neuronal impairments in mice. Eur J Pharmacol 2017; 804:38-45. [DOI: 10.1016/j.ejphar.2017.03.059] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2016] [Revised: 03/21/2017] [Accepted: 03/29/2017] [Indexed: 01/30/2023]
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27
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Bonfili L, Cecarini V, Berardi S, Scarpona S, Suchodolski JS, Nasuti C, Fiorini D, Boarelli MC, Rossi G, Eleuteri AM. Microbiota modulation counteracts Alzheimer's disease progression influencing neuronal proteolysis and gut hormones plasma levels. Sci Rep 2017; 7:2426. [PMID: 28546539 PMCID: PMC5445077 DOI: 10.1038/s41598-017-02587-2] [Citation(s) in RCA: 283] [Impact Index Per Article: 40.4] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/13/2016] [Accepted: 04/12/2017] [Indexed: 02/07/2023] Open
Abstract
Gut microbiota has a proven role in regulating multiple neuro-chemical pathways through the highly interconnected gut-brain axis. Oral bacteriotherapy thus has potential in the treatment of central nervous system-related pathologies, such as Alzheimer’s disease (AD). Current AD treatments aim to prevent onset, delay progression and ameliorate symptoms. In this work, 3xTg-AD mice in the early stage of AD were treated with SLAB51 probiotic formulation, thereby affecting the composition of gut microbiota and its metabolites. This influenced plasma concentration of inflammatory cytokines and key metabolic hormones considered therapeutic targets in neurodegeneration. Treated mice showed partial restoration of two impaired neuronal proteolytic pathways (the ubiquitin proteasome system and autophagy). Their cognitive decline was decreased compared with controls, due to a reduction in brain damage and reduced accumulation of amyloid beta aggregates. Collectively, our results clearly prove that modulation of the microbiota induces positive effects on neuronal pathways that are able to slow down the progression of Alzheimer’s disease.
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Affiliation(s)
- Laura Bonfili
- School of Biosciences and Veterinary Medicine, University of Camerino, via Gentile III da Varano, 62032, Camerino, (MC), Italy.
| | - Valentina Cecarini
- School of Biosciences and Veterinary Medicine, University of Camerino, via Gentile III da Varano, 62032, Camerino, (MC), Italy
| | - Sara Berardi
- School of Biosciences and Veterinary Medicine, University of Camerino, via Gentile III da Varano, 62032, Camerino, (MC), Italy
| | - Silvia Scarpona
- School of Biosciences and Veterinary Medicine, University of Camerino, via Gentile III da Varano, 62032, Camerino, (MC), Italy
| | - Jan S Suchodolski
- Gastrointestinal Laboratory, Department of Small Animal Clinical Sciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, USA
| | - Cinzia Nasuti
- School of Pharmacy, Pharmacology Unit, University of Camerino, via Madonna delle Carceri, 62032, Camerino, (MC), Italy
| | - Dennis Fiorini
- Division of Chemistry, School of Science and Technology, University of Camerino, I-62032, Camerino, MC, Italy
| | - Maria Chiara Boarelli
- Division of Chemistry, School of Science and Technology, University of Camerino, I-62032, Camerino, MC, Italy
| | - Giacomo Rossi
- School of Biosciences and Veterinary Medicine, University of Camerino, via Gentile III da Varano, 62032, Camerino, (MC), Italy
| | - Anna Maria Eleuteri
- School of Biosciences and Veterinary Medicine, University of Camerino, via Gentile III da Varano, 62032, Camerino, (MC), Italy
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28
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Keshava HB, Mowla A, Heinberg LJ, Schauer PR, Brethauer SA, Aminian A. Bariatric surgery may reduce the risk of Alzheimer's diseases through GLP-1 mediated neuroprotective effects. Med Hypotheses 2017; 104:4-9. [PMID: 28673587 DOI: 10.1016/j.mehy.2017.05.002] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2016] [Revised: 04/26/2017] [Accepted: 05/01/2017] [Indexed: 12/25/2022]
Abstract
Obesity and diabetes are associated with deficits in multiple neurocognitive domains and increased risk for dementia. Over the last two decades, there has been a significant increase in bariatric and metabolic surgery worldwide, driven by rising intertwined pandemics of obesity and diabetes, along with improvement in surgical techniques. Patients undergoing bariatric surgery achieve a significant decrease in their excess weight and a multitude of sequela associated with obesity, diabetes, and metabolic syndrome. Glucagon-like peptide 1 (GLP-1) is an intestinal peptide that has been implicated as one of the weight loss-independent mechanisms in how bariatric surgery affects type 2 diabetes. GLP-1 improves insulin secretion, inhibits apoptosis and induce pancreatic islet neogenesis, promotes satiety, and can regulate heart rate and blood pressure. Moreover, numerous studies have demonstrated potential neuroprotective and neurotrophic effects of GLP-1. Increased GLP-1 activity has been shown to increase cortical activity, promote neuronal growth, and inhibit neuronal degeneration. Specifically, in experimental studies on Alzheimer's disease, GLP-1 decreases amyloid deposition and neurofibrillary tangles. Furthermore, recent studies have also suggested that GLP-1 based therapies, new class of antidiabetic drugs, have favorable effects on neurodegenerative disorders such as Alzheimer's disease. We present a hypothesis that bariatric surgery can help delay or even prevent the onset of Alzheimer's disease in long-term by increasing the levels of GLP-1. This hypothesis has a potential for many studies from basic science projects to large population studies to fully understand the neurological and cognitive consequences of bariatric surgery and associated rise in GLP-1.
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Affiliation(s)
- Hari B Keshava
- Bariatric and Metabolic Institute, Department of General Surgery, Cleveland Clinic, Cleveland, OH, United States
| | - Ashkan Mowla
- Department of Neurology, Gates Vascular Institute, State University of New York (SUNY) at Buffalo, Buffalo, NY, United States
| | - Leslie J Heinberg
- Bariatric and Metabolic Institute, Department of General Surgery, Cleveland Clinic, Cleveland, OH, United States
| | - Philip R Schauer
- Bariatric and Metabolic Institute, Department of General Surgery, Cleveland Clinic, Cleveland, OH, United States
| | - Stacy A Brethauer
- Bariatric and Metabolic Institute, Department of General Surgery, Cleveland Clinic, Cleveland, OH, United States
| | - Ali Aminian
- Bariatric and Metabolic Institute, Department of General Surgery, Cleveland Clinic, Cleveland, OH, United States.
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29
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Zhang SX, Cai HY, Ma XW, Yuan L, Zhang J, Wang ZJ, Li YF, Qi JS. GLP-1 analogue CJC-1131 prevents amyloid β protein-induced impirments of spatial memory and synaptic plasticity in rats. Behav Brain Res 2017; 326:237-243. [DOI: 10.1016/j.bbr.2017.03.018] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 03/04/2017] [Accepted: 03/08/2017] [Indexed: 11/27/2022]
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30
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Li Y, Liu W, Li L, Hölscher C. D-Ala2-GIP-glu-PAL is neuroprotective in a chronic Parkinson's disease mouse model and increases BNDF expression while reducing neuroinflammation and lipid peroxidation. Eur J Pharmacol 2017; 797:162-172. [DOI: 10.1016/j.ejphar.2016.11.050] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2016] [Revised: 11/18/2016] [Accepted: 11/28/2016] [Indexed: 12/21/2022]
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31
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Higgins PB, Shade RE, Rodríguez-Sánchez IP, Garcia-Forey M, Tejero ME, Voruganti VS, Cole SA, Comuzzie AG, Folli F. Central GIP signaling stimulates peripheral GIP release and promotes insulin and pancreatic polypeptide secretion in nonhuman primates. Am J Physiol Endocrinol Metab 2016; 311:E661-E670. [PMID: 27530231 PMCID: PMC5241561 DOI: 10.1152/ajpendo.00166.2016] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/27/2016] [Accepted: 08/10/2016] [Indexed: 01/07/2023]
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) has important actions on whole body metabolic function. GIP and its receptor are also present in the central nervous system and have been linked to neurotrophic actions. Metabolic effects of central nervous system GIP signaling have not been reported. We investigated whether centrally administered GIP could increase peripheral plasma GIP concentrations and influence the metabolic response to a mixed macronutrient meal in nonhuman primates. An infusion and sampling system was developed to enable continuous intracerebroventricular (ICV) infusions with serial venous sampling in conscious nonhuman primates. Male baboons (Papio sp.) that were healthy and had normal body weights (28.9 ± 2.1 kg) were studied (n = 3). Animals were randomized to receive continuous ICV infusions of GIP (20 pmol·kg-1·h-1) or vehicle before and over the course of a 300-min mixed meal test (15 kcal/kg, 1.5g glucose/kg) on two occasions. A significant increase in plasma GIP concentration was observed under ICV GIP infusion (66.5 ± 8.0 vs. 680.6 ± 412.8 pg/ml, P = 0.04) before administration of the mixed meal. Increases in postprandial, but not fasted, insulin (P = 0.01) and pancreatic polypeptide (P = 0.04) were also observed under ICV GIP. Effects of ICV GIP on fasted or postprandial glucagon, glucose, triglyceride, and free fatty acids were not observed. Our data demonstrate that central GIP signaling can promote increased plasma GIP concentrations independent of nutrient stimulation and increase insulin and pancreatic polypeptide responses to a mixed meal.
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Affiliation(s)
- Paul B Higgins
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, Texas; Southwest National Primate Research Center, San Antonio, Texas;
| | - Robert E Shade
- Southwest National Primate Research Center, San Antonio, Texas
| | - Irám P Rodríguez-Sánchez
- Department of Genetics, School of Medicine, Autonomous University of Nuevo León (Universidad Autonoma de Nuevo León), Monterrey, Nuevo León, Mexico
| | | | - M Elizabeth Tejero
- Laboratory of Nutrigenetics and Nutrigenomics, National Institute of Genomic Medicine (Instituto Nacional de Medicina Genómica), Mexico City, Mexico
| | - V Saroja Voruganti
- Department of Nutrition and UNC Nutrition Research Institute, University of North Carolina at Chapel Hill, Kannapolis, North Carolina
| | - Shelley A Cole
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, Texas
| | - Anthony G Comuzzie
- Department of Genetics, Texas Biomedical Research Institute, San Antonio, Texas; Southwest National Primate Research Center, San Antonio, Texas
| | - Franco Folli
- Southwest National Primate Research Center, San Antonio, Texas; Diabetes Division, Department of Medicine, University of Texas Health Sciences Center at San Antonio, San Antonio, Texas; Department of Medicine, Obesity and Comorbidities Research Center, University of Campinas, Campinas, São Paulo, Brazil; and Dipartimento di Scienze della Salute, Università degli Studi di Milano, Milan, Italy
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32
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Sekar R, Singh K, Arokiaraj AWR, Chow BKC. Pharmacological Actions of Glucagon-Like Peptide-1, Gastric Inhibitory Polypeptide, and Glucagon. INTERNATIONAL REVIEW OF CELL AND MOLECULAR BIOLOGY 2016; 326:279-341. [PMID: 27572131 DOI: 10.1016/bs.ircmb.2016.05.002] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Glucagon family of peptide hormones is a group of structurally related brain-gut peptides that exert their pleiotropic actions through interactions with unique members of class B1 G protein-coupled receptors (GPCRs). They are key regulators of hormonal homeostasis and are important drug targets for metabolic disorders such as type-2 diabetes mellitus (T2DM), obesity, and dysregulations of the nervous systems such as migraine, anxiety, depression, neurodegeneration, psychiatric disorders, and cardiovascular diseases. The current review aims to provide a detailed overview of the current understanding of the pharmacological actions and therapeutic advances of three members within this family including glucagon-like peptide-1 (GLP-1), gastric inhibitory polypeptide (GIP), and glucagon.
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Affiliation(s)
- R Sekar
- School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - K Singh
- School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - A W R Arokiaraj
- School of Biological Sciences, University of Hong Kong, Hong Kong, China
| | - B K C Chow
- School of Biological Sciences, University of Hong Kong, Hong Kong, China.
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33
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Yu YW, Hsieh TH, Chen KY, Wu JCC, Hoffer BJ, Greig NH, Li Y, Lai JH, Chang CF, Lin JW, Chen YH, Yang LY, Chiang YH. Glucose-Dependent Insulinotropic Polypeptide Ameliorates Mild Traumatic Brain Injury-Induced Cognitive and Sensorimotor Deficits and Neuroinflammation in Rats. J Neurotrauma 2016; 33:2044-2054. [PMID: 26972789 PMCID: PMC5116684 DOI: 10.1089/neu.2015.4229] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
Mild traumatic brain injury (mTBI) is a major public health issue, representing 75-90% of all cases of TBI. In clinical settings, mTBI, which is defined as a Glascow Coma Scale (GCS) score of 13-15, can lead to various physical, cognitive, emotional, and psychological-related symptoms. To date, there are no pharmaceutical-based therapies to manage the development of the pathological deficits associated with mTBI. In this study, the neurotrophic and neuroprotective properties of glucose-dependent insulinotropic polypeptide (GIP), an incretin similar to glucagon-like peptide-1 (GLP-1), was investigated after its steady-state subcutaneous administration, focusing on behavior after mTBI in an in vivo animal model. The mTBI rat model was generated by a mild controlled cortical impact (mCCI) and used to evaluate the therapeutic potential of GIP. We used the Morris water maze and novel object recognition tests, which are tasks for spatial and recognition memory, respectively, to identify the putative therapeutic effects of GIP on cognitive function. Further, beam walking and the adhesive removal tests were used to evaluate locomotor activity and somatosensory functions in rats with and without GIP administration after mCCI lesion. Lastly, we used immunohistochemical (IHC) staining and Western blot analyses to evaluate the inflammatory markers, glial fibrillary acidic protein (GFAP), amyloid-β precursor protein (APP), and bone marrow tyrosine kinase gene in chromosome X (BMX) in animals with mTBI. GIP was well tolerated and ameliorated mTBI-induced memory impairments, poor balance, and sensorimotor deficits after initiation in the post-injury period. In addition, GIP mitigated mTBI-induced neuroinflammatory changes on GFAP, APP, and BMX protein levels. These findings suggest GIP has significant benefits in managing mTBI-related symptoms and represents a novel strategy for mTBI treatment.
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Affiliation(s)
- Yu-Wen Yu
- 1 PhD Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes , Taipei, Taiwan
| | - Tsung-Hsun Hsieh
- 1 PhD Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes , Taipei, Taiwan .,2 Center for Neurotrauma and Neuroregeneration, Taipei Medical University , Taipei, Taiwan .,3 Department of Physical Therapy and Graduate Institute of Rehabilitation Science, College of Medicine, Chang Gung University , Taoyuan, Taiwan
| | - Kai-Yun Chen
- 1 PhD Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes , Taipei, Taiwan .,2 Center for Neurotrauma and Neuroregeneration, Taipei Medical University , Taipei, Taiwan
| | - John Chung-Che Wu
- 4 Department of Surgery, College of Medicine, Taipei Medical University , Taipei, Taiwan
| | - Barry J Hoffer
- 1 PhD Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes , Taipei, Taiwan .,5 Department of Neurosurgery, Case Western Reserve University , School of Medicine, Cleveland, Ohio
| | - Nigel H Greig
- 6 Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health , Baltimore, Maryland
| | - Yazhou Li
- 6 Drug Design & Development Section, Translational Gerontology Branch, Intramural Research Program, National Institute on Aging, National Institutes of Health , Baltimore, Maryland
| | - Jing-Huei Lai
- 2 Center for Neurotrauma and Neuroregeneration, Taipei Medical University , Taipei, Taiwan .,4 Department of Surgery, College of Medicine, Taipei Medical University , Taipei, Taiwan
| | - Cheng-Fu Chang
- 4 Department of Surgery, College of Medicine, Taipei Medical University , Taipei, Taiwan
| | - Jia-Wei Lin
- 4 Department of Surgery, College of Medicine, Taipei Medical University , Taipei, Taiwan
| | - Yu-Hsin Chen
- 7 Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University , Taipei, Taiwan .,8 Graduate Institute of Medical Sciences, College of Medicine, Taipei Medical University , Taipei, Taiwan
| | - Liang-Yo Yang
- 7 Department of Physiology, School of Medicine, College of Medicine, Taipei Medical University , Taipei, Taiwan .,9 Research Center for Biomedical Devices and Prototyping Production, Taipei Medical University , Taipei, Taiwan .,11 School of Medicine, College of Medicine, China Medical University, Taichung, Taiwan
| | - Yung-Hsiao Chiang
- 1 PhD Program for Neural Regenerative Medicine, College of Medical Science and Technology, Taipei Medical University and National Health Research Institutes , Taipei, Taiwan .,2 Center for Neurotrauma and Neuroregeneration, Taipei Medical University , Taipei, Taiwan .,4 Department of Surgery, College of Medicine, Taipei Medical University , Taipei, Taiwan .,10 Translational Laboratory, Department of Medical Research, Taipei Medical University Hospital, Taipei, Taiwan
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34
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Li Y, Liu W, Li L, Hölscher C. Neuroprotective effects of a GIP analogue in the MPTP Parkinson's disease mouse model. Neuropharmacology 2016; 101:255-63. [DOI: 10.1016/j.neuropharm.2015.10.002] [Citation(s) in RCA: 53] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2015] [Revised: 09/06/2015] [Accepted: 10/02/2015] [Indexed: 12/25/2022]
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35
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Groeneveld ON, Kappelle LJ, Biessels GJ. Potentials of incretin-based therapies in dementia and stroke in type 2 diabetes mellitus. J Diabetes Investig 2016; 7:5-16. [PMID: 26816596 PMCID: PMC4718099 DOI: 10.1111/jdi.12420] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/04/2015] [Revised: 08/12/2015] [Accepted: 08/17/2015] [Indexed: 12/18/2022] Open
Abstract
Patients with type 2 diabetes mellitus are at risk for accelerated cognitive decline and dementia. Furthermore, their risk of stroke is increased and their outcome after stroke is worse than in those without diabetes. Incretin-based therapies are a class of antidiabetic agents that are of interest in relation to these cerebral complications of diabetes. Two classes of incretin-based therapies are currently available: the glucagon-like-peptide-1 agonists and the dipeptidyl peptidase-4 -inhibitors. Independent of their glucose-lowering effects, incretin-based therapies might also have direct or indirect beneficial effects on the brain. In the present review, we discuss the potential of incretin-based therapies in relation to dementia, in particular Alzheimer's disease, and stroke in patients with type 2 diabetes. Experimental studies on Alzheimer's disease have found beneficial effects of incretin-based therapies on cognition, synaptic plasticity and metabolism of amyloid-β and microtubule-associated protein tau. Preclinical studies on incretin-based therapies in stroke have shown an improved functional outcome, a reduction of infarct volume as well as neuroprotective and neurotrophic properties. Both with regard to the treatment of Alzheimer's disease, and with regard to prevention and treatment of stroke, randomized controlled trials in patients with or without diabetes are underway. In conclusion, experimental studies show promising results of incretin-based therapies at improving the outcome of Alzheimer's disease and stroke through glucose-independent pleiotropic effects on the brain. If these findings would indeed be confirmed in large clinical randomized controlled trials, this would have substantial impact.
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Affiliation(s)
- Onno N Groeneveld
- University Medical Center UtrechtBrain Center Rudolf MagnusDepartment of NeurologyUtrechtthe Netherlands
| | - L Jaap Kappelle
- University Medical Center UtrechtBrain Center Rudolf MagnusDepartment of NeurologyUtrechtthe Netherlands
| | - Geert Jan Biessels
- University Medical Center UtrechtBrain Center Rudolf MagnusDepartment of NeurologyUtrechtthe Netherlands
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Marcos ABW, Forner S, Martini AC, Patrício ES, Clarke JR, Costa R, Felix-Alves J, Vieira VJ, de Andrade EL, Mazzuco TL, Calixto JB, Figueiredo CP. Temporal and Regional Expression of Glucose-Dependent Insulinotropic Peptide and Its Receptor in Spinal Cord Injured Rats. J Neurotrauma 2015; 33:261-8. [PMID: 26421658 DOI: 10.1089/neu.2015.3877] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/19/2023] Open
Abstract
Spinal cord injury (SCI) results in loss of movement, sensibility, and autonomic control at the level of the lesion and at lower parts of the body. Several experimental strategies have been used in attempts to increase endogenous mechanisms of neuroprotection, neuroplasticity, and repair, but with limited success. It is known that glucose-dependent insulinotropic peptide (GIP) and its receptor (GIPR) can enhance synaptic plasticity, neurogenesis, and axonal outgrowth. However, their role in the injury has never been studied. The aim of this study was to evaluate the changes in expression levels of both GIP and GIPR in acute and chronic phases of SCI in rats. Following SCI (2 to 24 h after damage), the rat spinal cord showed a lesion in which the epicenter had a cavity with hemorrhage and necrosis. Furthermore, the lesion cavity also showed ballooned cells 14 and 28 days after injury. We found that SCI induced increases in GIPR expression in areas neighboring the site of injury at 6 h and 28 days after the injury. Moreover, higher GIP expression was observed in these regions on day 28. Neuronal projections from the injury epicenter showed an increase in GIP immunoreactivity 24 h and 14 and 28 days after SCI. Interestingly, GIP was also found in progenitor cells at the spinal cord canal 24 h after injury, whereas both GIP and GIPR were present in progenitor cells at the injury epicenter 14 days after in SCI animals. These results suggest that GIP and its receptor might be implicated with neurogenesis and the repair process after SCI.
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Affiliation(s)
- Ana Beatriz W Marcos
- 1 Programa de Pós-Graduação em Ciências Médicas, Centro de Ciências da Saúde, Universidade Federal de Santa Catarina (UFSC) , Florianópolis, SC, Brazil
| | - Stefania Forner
- 2 Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina (UFSC) , Florianópolis, SC, Brazil
| | - Alessandra C Martini
- 2 Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina (UFSC) , Florianópolis, SC, Brazil
| | - Eliziane S Patrício
- 2 Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina (UFSC) , Florianópolis, SC, Brazil
| | - Julia R Clarke
- 3 Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ) , Rio de Janeiro, RJ, Brazil
| | - Robson Costa
- 3 Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ) , Rio de Janeiro, RJ, Brazil
| | - João Felix-Alves
- 2 Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina (UFSC) , Florianópolis, SC, Brazil
| | - Vilberto José Vieira
- 1 Programa de Pós-Graduação em Ciências Médicas, Centro de Ciências da Saúde, Universidade Federal de Santa Catarina (UFSC) , Florianópolis, SC, Brazil
| | - Edinéia Lemos de Andrade
- 2 Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina (UFSC) , Florianópolis, SC, Brazil
| | - Tânia Longo Mazzuco
- 4 Departamento de Clínica Médica, Centro de Ciências da Saúde, Universidade Estadual de Londrina , PR, Brazil
| | - João Batista Calixto
- 2 Departamento de Farmacologia, Centro de Ciências Biológicas, Universidade Federal de Santa Catarina (UFSC) , Florianópolis, SC, Brazil
| | - Claudia Pinto Figueiredo
- 3 Faculdade de Farmácia, Centro de Ciências da Saúde, Universidade Federal do Rio de Janeiro (UFRJ) , Rio de Janeiro, RJ, Brazil
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Irwin N, Flatt PR. New perspectives on exploitation of incretin peptides for the treatment of diabetes and related disorders. World J Diabetes 2015; 6:1285-1295. [PMID: 26557956 PMCID: PMC4635139 DOI: 10.4239/wjd.v6.i15.1285] [Citation(s) in RCA: 42] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/20/2015] [Revised: 09/25/2015] [Accepted: 10/27/2015] [Indexed: 02/05/2023] Open
Abstract
The applicability of stable gut hormones for the treatment of obesity-related diabetes is now undisputable. This is based predominantly on prominent and sustained glucose-lowering actions, plus evidence that these peptides can augment insulin secretion and pancreatic islet function over time. This review highlights the therapeutic potential of glucagon-like peptide-1 (GLP-1), glucose-dependent insulinotropic polypeptide (GIP), oxyntomodulin (OXM) and cholecystokinin (CCK) for obesity-related diabetes. Stable GLP-1 mimetics have already been successfully adopted into the diabetic clinic, whereas GIP, CCK and OXM molecules offer promise as potential new classes of antidiabetic drugs. Moreover, recent studies have shown improved therapeutic effects following simultaneous modulation of multiple receptor signalling pathways by combination therapy or use of dual/triple agonist peptides. However, timing and composition of injections may be important to permit interludes of beta-cell rest. The review also addresses the possible perils of incretin based drugs for treatment of prediabetes. Finally, the unanticipated utility of stable gut peptides as effective treatments for complications of diabetes, bone disorders, cognitive impairment and cardiovascular dysfunction is considered.
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Welcome MO, Mastorakis NE, Pereverzev VA. Sweet taste receptor signaling network: possible implication for cognitive functioning. Neurol Res Int 2015; 2015:606479. [PMID: 25653876 PMCID: PMC4306214 DOI: 10.1155/2015/606479] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/03/2014] [Accepted: 12/20/2014] [Indexed: 01/01/2023] Open
Abstract
Sweet taste receptors are transmembrane protein network specialized in the transmission of information from special "sweet" molecules into the intracellular domain. These receptors can sense the taste of a range of molecules and transmit the information downstream to several acceptors, modulate cell specific functions and metabolism, and mediate cell-to-cell coupling through paracrine mechanism. Recent reports indicate that sweet taste receptors are widely distributed in the body and serves specific function relative to their localization. Due to their pleiotropic signaling properties and multisubstrate ligand affinity, sweet taste receptors are able to cooperatively bind multiple substances and mediate signaling by other receptors. Based on increasing evidence about the role of these receptors in the initiation and control of absorption and metabolism, and the pivotal role of metabolic (glucose) regulation in the central nervous system functioning, we propose a possible implication of sweet taste receptor signaling in modulating cognitive functioning.
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Affiliation(s)
- Menizibeya O. Welcome
- World Scientific and Engineering Academy and Society, Ag. Ioannou Theologou 17-23, Zografou, 15773 Athens, Greece
| | - Nikos E. Mastorakis
- World Scientific and Engineering Academy and Society, Ag. Ioannou Theologou 17-23, Zografou, 15773 Athens, Greece
- Department of Industrial Engineering, Technical University of Sofia, 8 Kl. Ohridski Boulevard, 1000 Sofia, Bulgaria
| | - Vladimir A. Pereverzev
- Department of Normal Physiology, Belarusian State Medical University, Dzerzhinsky Avenue 83, 220116 Minsk, Belarus
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Abstract
Gastric inhibitory polypeptide (GIP) and glucagon‐like peptide‐1 (GLP‐1) are the two primary incretin hormones secreted from the intestine on ingestion of glucose or nutrients to stimulate insulin secretion from pancreatic β cells. GIP and GLP‐1 exert their effects by binding to their specific receptors, the GIP receptor (GIPR) and the GLP‐1 receptor (GLP‐1R), which belong to the G‐protein coupled receptor family. Receptor binding activates and increases the level of intracellular cyclic adenosine monophosphate in pancreatic β cells, thereby stimulating insulin secretion glucose‐dependently. In addition to their insulinotropic effects, GIP and GLP‐1 play critical roles in various biological processes in different tissues and organs that express GIPR and GLP‐1R, including the pancreas, fat, bone and the brain. Within the pancreas, GIP and GLP‐1 together promote β cell proliferation and inhibit apoptosis, thereby expanding pancreatic β cell mass, while GIP enhances postprandial glucagon response and GLP‐1 suppresses it. In adipose tissues, GIP but not GLP‐1 facilitates fat deposition. In bone, GIP promotes bone formation while GLP‐1 inhibits bone absorption. In the brain, both GIP and GLP‐1 are thought to be involved in memory formation as well as the control of appetite. In addition to these differences, secretion of GIP and GLP‐1 and their insulinotropic effects on β cells have been shown to differ in patients with type 2 diabetes compared to healthy subjects. We summarize here the similarities and differences of these two incretin hormones in secretion and metabolism, their insulinotropic action on pancreatic β cells, and their non‐insulinotropic effects, and discuss their potential in treatment of type 2 diabetes. (J Diabetes Invest, doi: 10.1111/j.2040‐1124.2010.00022.x, 2010)
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Affiliation(s)
- Yutaka Seino
- The Division of Diabetes, Clinical Nutrition and Endocrinology, Kansai Electric Power Hospital, Osaka
| | - Mitsuo Fukushima
- The Division of Diabetes, Clinical Nutrition and Endocrinology, Kansai Electric Power Hospital, Osaka ; The Department of Nutritional Science, Okayama Prefectural University, Okayama, Japan
| | - Daisuke Yabe
- The Division of Diabetes, Clinical Nutrition and Endocrinology, Kansai Electric Power Hospital, Osaka
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Seino Y, Yabe D. Glucose-dependent insulinotropic polypeptide and glucagon-like peptide-1: Incretin actions beyond the pancreas. J Diabetes Investig 2014; 4:108-30. [PMID: 24843641 PMCID: PMC4019264 DOI: 10.1111/jdi.12065] [Citation(s) in RCA: 183] [Impact Index Per Article: 18.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/16/2013] [Accepted: 01/24/2013] [Indexed: 12/14/2022] Open
Abstract
Glucose-dependent insulinotropic polypeptide (GIP) and glucagon-like peptide-1 (GLP-1) are the two primary incretin hormones secreted from the intestine on ingestion of various nutrients to stimulate insulin secretion from pancreatic β-cells glucose-dependently. GIP and GLP-1 undergo degradation by dipeptidyl peptidase-4 (DPP-4), and rapidly lose their biological activities. The actions of GIP and GLP-1 are mediated by their specific receptors, the GIP receptor (GIPR) and the GLP-1 receptor (GLP-1R), which are expressed in pancreatic β-cells, as well as in various tissues and organs. A series of investigations using mice lacking GIPR and/or GLP-1R, as well as mice lacking DPP-4, showed involvement of GIP and GLP-1 in divergent biological activities, some of which could have implications for preventing diabetes-related microvascular complications (e.g., retinopathy, nephropathy and neuropathy) and macrovascular complications (e.g., coronary artery disease, peripheral artery disease and cerebrovascular disease), as well as diabetes-related comorbidity (e.g., obesity, non-alcoholic fatty liver disease, bone fracture and cognitive dysfunction). Furthermore, recent studies using incretin-based drugs, such as GLP-1 receptor agonists, which stably activate GLP-1R signaling, and DPP-4 inhibitors, which enhance both GLP-1R and GIPR signaling, showed that GLP-1 and GIP exert effects possibly linked to prevention or treatment of diabetes-related complications and comorbidities independently of hyperglycemia. We review recent findings on the extrapancreatic effects of GIP and GLP-1 on the heart, brain, kidney, eye and nerves, as well as in the liver, fat and several organs from the perspective of diabetes-related complications and comorbidities.
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Affiliation(s)
| | - Daisuke Yabe
- Division of Diabetes Clinical Nutrition and Endocrinology Kansai Electric Power Hospital Osaka Japan
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Transcriptional analysis of apoptotic cerebellar granule neurons following rescue by gastric inhibitory polypeptide. Int J Mol Sci 2014; 15:5596-622. [PMID: 24694544 PMCID: PMC4013584 DOI: 10.3390/ijms15045596] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/27/2014] [Revised: 03/04/2014] [Accepted: 03/17/2014] [Indexed: 12/31/2022] Open
Abstract
Apoptosis triggered by exogenous or endogenous stimuli is a crucial phenomenon to determine the fate of neurons, both in physiological and in pathological conditions. Our previous study established that gastric inhibitory polypeptide (Gip) is a neurotrophic factor capable of preventing apoptosis of cerebellar granule neurons (CGNs), during its pre-commitment phase. In the present study, we conducted whole-genome expression profiling to obtain a comprehensive view of the transcriptional program underlying the rescue effect of Gip in CGNs. By using DNA microarray technology, we identified 65 genes, we named survival related genes, whose expression is significantly de-regulated following Gip treatment. The expression levels of six transcripts were confirmed by real-time quantitative polymerase chain reaction. The proteins encoded by the survival related genes are functionally grouped in the following categories: signal transduction, transcription, cell cycle, chromatin remodeling, cell death, antioxidant activity, ubiquitination, metabolism and cytoskeletal organization. Our data outline that Gip supports CGNs rescue via a molecular framework, orchestrated by a wide spectrum of gene actors, which propagate survival signals and support neuronal viability.
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Hölscher C. The incretin hormones glucagonlike peptide 1 and glucose-dependent insulinotropic polypeptide are neuroprotective in mouse models of Alzheimer's disease. Alzheimers Dement 2014; 10:S47-54. [DOI: 10.1016/j.jalz.2013.12.009] [Citation(s) in RCA: 90] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2013] [Accepted: 12/05/2013] [Indexed: 12/25/2022]
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Yabe D, Seino Y. Incretin actions beyond the pancreas: lessons from knockout mice. Curr Opin Pharmacol 2013; 13:946-53. [DOI: 10.1016/j.coph.2013.09.013] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/04/2013] [Revised: 09/13/2013] [Accepted: 09/13/2013] [Indexed: 02/06/2023]
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Okawa T, Kamiya H, Himeno T, Seino Y, Tsunekawa S, Hayashi Y, Harada N, Yamada Y, Inagaki N, Seino Y, Oiso Y, Nakamura J. Sensory and motor physiological functions are impaired in gastric inhibitory polypeptide receptor-deficient mice. J Diabetes Investig 2013; 5:31-7. [PMID: 24843734 PMCID: PMC4025241 DOI: 10.1111/jdi.12129] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/31/2013] [Revised: 05/24/2013] [Accepted: 06/18/2013] [Indexed: 12/21/2022] Open
Abstract
AIMS/INTRODUCTION Gastric inhibitory polypeptide (GIP) is an incretin secreted from the gastrointestinal tract after an ingestion of nutrients, and stimulates an insulin secretion from the pancreatic islets. Additionally, GIP has important roles in extrapancreatic tissues: fat accumulation in adipose tissue, neuroprotective effects in the central nervous system and an inhibition of bone resorption. In the current study, we investigated the effects of GIP signaling on the peripheral nervous system (PNS). MATERIALS AND METHODS First, the presence of the GIP receptor (GIPR) in mouse dorsal root ganglion (DRG) was evaluated utilizing immunohistochemical analysis, western blotting and reverse transcription polymerase chain reaction. DRG neurons of male wild-type mice (WT) were cultured with or without GIP, and their neurite lengths were quantified. Functions of the PNS were evaluated in GIPR-deficient mice (gipr-/-) and WT by using current perception thresholds (CPTs), Thermal Plantar Test (TPT), and motor (MNCV) and sensory nerve conduction velocity (SNCV, respectively). Sciatic nerve blood flow (SNBF) and plantar skin blood flow (PSBF) were also evaluated. RESULTS We confirmed the expression of GIPR in DRG neurons. The neurite outgrowths of DRG neurons were promoted by the GIP administrations. The gipr-/- showed impaired perception functions in the examination of CPTs and TPT. Both MNCV and SNCV were delayed in gipr-/- compared with these in WT. There was no difference in SNBF and PSBF between WT and gipr-/-. CONCLUSIONS Our findings show that the GIP signal could exert direct physiological roles in the PNS, which might be directly exerted on the PNS.
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Affiliation(s)
- Tetsuji Okawa
- Department of Endocrinology and Diabetes Nagoya University Graduate School of Medicine Nagoya Japan
| | - Hideki Kamiya
- Department of Chronic Kidney Disease Initiatives Nagoya University Graduate School of Medicine Nagoya Japan
| | - Tatsuhito Himeno
- Department of Endocrinology and Diabetes Nagoya University Graduate School of Medicine Nagoya Japan
| | - Yusuke Seino
- Department of Metabolic Medicine Nagoya University School of Medicine Nagoya Japan
| | - Shin Tsunekawa
- Department of Endocrinology and Diabetes Nagoya University Graduate School of Medicine Nagoya Japan
| | - Yoshitaka Hayashi
- Department of Genetics Research Institute of Environmental Medicine Nagoya University Nagoya Japan
| | - Norio Harada
- Department of Diabetes and Clinical Nutrition Kyoto University Graduate School of Medicine Kyoto Japan
| | - Yuichiro Yamada
- Department of Endocrinology Diabetes and Geriatric Medicine Akita University Graduate School of Medicine Akita Japan
| | - Nobuya Inagaki
- Department of Diabetes and Clinical Nutrition Kyoto University Graduate School of Medicine Kyoto Japan
| | | | - Yutaka Oiso
- Department of Endocrinology and Diabetes Nagoya University Graduate School of Medicine Nagoya Japan
| | - Jiro Nakamura
- Department of Endocrinology and Diabetes Nagoya University Graduate School of Medicine Nagoya Japan
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Beck B, Pourié G. Ghrelin, neuropeptide Y, and other feeding-regulatory peptides active in the hippocampus: role in learning and memory. Nutr Rev 2013; 71:541-61. [PMID: 23865799 DOI: 10.1111/nure.12045] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The hippocampus is a brain region of primary importance for neurogenesis, which occurs during early developmental states as well as during adulthood. Increases in neuronal proliferation and in neuronal death with age have been associated with drastic changes in memory and learning. Numerous neurotransmitters are involved in these processes, and some neuropeptides that mediate neurogenesis also modulate feeding behavior. Concomitantly, feeding peptides, which act primarily in the hypothalamus, are also present in the hippocampus. This review aims to ascertain the role of several important feeding peptides in cognitive functions, either through their local synthesis in the hippocampus or through their actions via specific receptors in the hippocampus. A link between neurogenesis and the orexigenic or anorexigenic properties of feeding peptides is discussed.
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Affiliation(s)
- Bernard Beck
- INSERM U954, Nutrition, Génétique et Expositions aux Risques Environnementaux, Faculté de Médecine, Vandœuvre, France.
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Abstract
Incretin peptides, principally GLP-1 and GIP, regulate islet hormone secretion, glucose concentrations, lipid metabolism, gut motility, appetite and body weight, and immune function, providing a scientific basis for utilizing incretin-based therapies in the treatment of type 2 diabetes. Activation of GLP-1 and GIP receptors also leads to nonglycemic effects in multiple tissues, through direct actions on tissues expressing incretin receptors and indirect mechanisms mediated through neuronal and endocrine pathways. Here we contrast the pharmacology and physiology of incretin hormones and review recent advances in mechanisms coupling incretin receptor signaling to pleiotropic metabolic actions in preclinical studies. We discuss whether mechanisms identified in preclinical studies have potential translational relevance for the treatment of human disease and highlight controversies and uncertainties in incretin biology that require resolution in future studies.
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Affiliation(s)
- Jonathan E Campbell
- Department of Medicine, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, ON M5G 1X5, Canada
| | - Daniel J Drucker
- Department of Medicine, Samuel Lunenfeld Research Institute, Mount Sinai Hospital, University of Toronto, Toronto, ON M5G 1X5, Canada.
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Hung WL, Hwang C, Gao S, Liao EH, Chitturi J, Wang Y, Li H, Stigloher C, Bessereau JL, Zhen M. Attenuation of insulin signalling contributes to FSN-1-mediated regulation of synapse development. EMBO J 2013; 32:1745-60. [PMID: 23665919 DOI: 10.1038/emboj.2013.91] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2012] [Accepted: 03/27/2013] [Indexed: 01/07/2023] Open
Abstract
A neuronal F-box protein FSN-1 regulates Caenorhabditis elegans neuromuscular junction development by negatively regulating DLK-mediated MAPK signalling. In the present study, we show that attenuation of insulin/IGF signalling also contributes to FSN-1-dependent synaptic development and function. The aberrant synapse morphology and synaptic transmission in fsn-1 mutants are partially and specifically rescued by reducing insulin/IGF-signalling activity in postsynaptic muscles, as well as by reducing the activity of EGL-3, a prohormone convertase that processes agonistic insulin/IGF ligands INS-4 and INS-6, in neurons. FSN-1 interacts with, and potentiates the ubiquitination of EGL-3 in vitro, and reduces the EGL-3 level in vivo. We propose that FSN-1 may negatively regulate insulin/IGF signalling, in part, through EGL-3-dependent insulin-like ligand processing.
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Affiliation(s)
- Wesley L Hung
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, Ontario, Canada
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Faivre E, Hölscher C. Neuroprotective effects of D-Ala(2)GIP on Alzheimer's disease biomarkers in an APP/PS1 mouse model. ALZHEIMERS RESEARCH & THERAPY 2013; 5:20. [PMID: 23601582 PMCID: PMC3706793 DOI: 10.1186/alzrt174] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 12/28/2012] [Revised: 03/09/2013] [Accepted: 04/08/2013] [Indexed: 12/16/2022]
Abstract
Introduction Type 2 diabetes mellitus has been identified as a risk factor for Alzheimer's disease (AD). An impairment of insulin signaling as well as a desensitization of its receptor has been found in AD brains. Glucose-dependent insulinotropic polypeptide (GIP) normalises insulin signaling by facilitating insulin release. GIP directly modulates neurotransmitter release, LTP formation, and protects synapses from the detrimental effects of beta-amyloid fragments on LTP formation, and cell proliferation of progenitor cells in the dentate gyrus. Here we investigate the potential therapeutic property of the new long lasting incretin hormone analogue D-Ala2GIP on key symptoms found in a mouse model of Alzheimer' disease (APPswe/PS1detaE9). Methods D-Ala2GIP was injected for 21 days at 25 nmol/kg ip once daily in APP/PS1 male mice and wild type (WT) littermates aged 6 or 12 months of age. Amyloid plaque load, inflammation biomarkers, synaptic plasticity in the brain (LTP), and memory were measured. Results D-Ala2GIP improved memory in WT mice and rescued the cognitive decline of 12 months old APP/PS1 mice in two different memory tasks. Furthermore, deterioration of synaptic function in the dentate gyrus and cortex was prevented in 12 months old APP/PS1 mice. D-Ala2GIP facilitated synaptic plasticity in APP/PS1 and WT mice and reduced the number of amyloid plaques in the cortex of D-Ala2GIP injected APP/PS1 mice. The inflammatory response in microglia was also reduced. Conclusion The results demonstrate that D-Ala2GIP has neuroprotective properties on key hallmarks found in AD. This finding shows that novel GIP analogues have the potential as a novel therapeutic for AD.
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Affiliation(s)
- Emilie Faivre
- School of Biomedical Sciences, Ulster University, Cromore road, Coleraine, BT52 1SA, UK
| | - Christian Hölscher
- School of Biomedical Sciences, Ulster University, Cromore road, Coleraine, BT52 1SA, UK
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Duffy AM, Hölscher C. The incretin analogue D-Ala2GIP reduces plaque load, astrogliosis and oxidative stress in an APP/PS1 mouse model of Alzheimer's disease. Neuroscience 2012; 228:294-300. [PMID: 23103794 DOI: 10.1016/j.neuroscience.2012.10.045] [Citation(s) in RCA: 76] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2012] [Accepted: 10/19/2012] [Indexed: 12/24/2022]
Abstract
Type 2 diabetes mellitus has been identified as a risk factor for Alzheimer's disease (AD). Insulin is a neuroprotective growth factor, and an impairment of insulin signalling has been found in AD brains. Glucose-dependent insulinotropic polypeptide (GIP), an incretin hormone, normalises insulin signalling and also acts as a neuroprotective growth factor. GIP plays an important role in memory formation, synaptic plasticity and cell proliferation. We have shown previously that the long-lasting incretin hormone analogue D-Ala(2)GIP protects memory formation and synaptic plasticity, reduces plaques, normalises the proliferation of stem cells, reduces the activation of microglia, and prevents the loss of synapses in the cortex of the APPswe/PS1deltaE9 mouse model of Alzheimer's disease. D-Ala(2)GIP was injected for 35 days at 25 nmol/kg i.p. once daily in APP/PS1 male mice and wild-type (WT) littermates aged 6, 12 and 19 months. In a follow-up study, we analysed plaque load, the activation of astrocytes as a means of chronic inflammation in the brain, and oxidative stress in the brains of these mice (8-oxoguanine levels). D-Ala(2)GIP reduced the amyloid plaque load in 12- and 19-month-old mice, and the inflammation response as shown in the reduction of activated astrocytes in 12- and 19-month old APP/PS1 mice. Chronic oxidative stress in the brain was reduced in 12- and 19-month-old mice as shown in the reduction of 8-oxoguanine levels in the cortex of D-Ala(2)GIP-injected APP/PS1 mice. The results demonstrate that D-Ala(2)GIP has neuroprotective properties on key markers found in Alzheimer's disease. This finding shows that novel GIP analogues have the potential to be developed as novel therapeutics for Alzheimer's disease.
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Affiliation(s)
- A M Duffy
- School of Biomedical Sciences, Ulster University, Coleraine, United Kingdom
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Porter D, Faivre E, Flatt PR, Hölscher C, Gault VA. Actions of incretin metabolites on locomotor activity, cognitive function and in vivo hippocampal synaptic plasticity in high fat fed mice. Peptides 2012; 35:1-8. [PMID: 22465882 DOI: 10.1016/j.peptides.2012.03.014] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 03/16/2012] [Accepted: 03/16/2012] [Indexed: 02/05/2023]
Abstract
The incretin hormones glucagon-like peptide-1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP) improve markers of cognitive function in obesity-diabetes, however, both are rapidly degraded to their major metabolites, GLP-1(9-36)amide and GIP(3-42), respectively. Therefore, the present study investigated effects of GLP-1(9-36)amide and GIP(3-42) on locomotor activity, cognitive function and hippocampal synaptic plasticity in mice with diet-induced obesity and insulin resistance. High-fat fed Swiss TO mice treated with GLP-1(9-36)amide, GIP(3-42) or exendin(9-39)amide (twice-daily for 60 days) did not exhibit any changes in bodyweight, non-fasting plasma glucose and plasma insulin concentrations or glucose tolerance compared with high-fat saline controls. Similarly, locomotor and feeding activity, O(2) consumption, CO(2) production, respiratory exchange ratio and energy expenditure were not altered by chronic treatment with incretin metabolites. Administration of the truncated metabolites did not alter general behavior in an open field test or learning and memory ability as recorded during an object recognition test. High-fat mice exhibited a significant impairment in hippocampal long-term potentiation (LTP) which was not affected by treatment with incretin metabolites. These data indicate that incretin metabolites do not influence locomotor activity, cognitive function and hippocampal synaptic plasticity when administered at pharmacological doses to mice fed a high-fat diet.
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Affiliation(s)
- David Porter
- The SAAD Centre for Pharmacy and Diabetes, School of Biomedical Sciences, University of Ulster, Coleraine BT52 1SA, Northern Ireland, United Kingdom
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