1
|
Hussain G, Akram R, Anwar H, Sajid F, Iman T, Han HS, Raza C, De Aguilar JLG. Adult neurogenesis: a real hope or a delusion? Neural Regen Res 2024; 19:6-15. [PMID: 37488837 PMCID: PMC10479850 DOI: 10.4103/1673-5374.375317] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2023] [Revised: 02/27/2023] [Accepted: 04/10/2023] [Indexed: 07/26/2023] Open
Abstract
Adult neurogenesis, the process of creating new neurons, involves the coordinated division, migration, and differentiation of neural stem cells. This process is restricted to neurogenic niches located in two distinct areas of the brain: the subgranular zone of the dentate gyrus of the hippocampus and the subventricular zone of the lateral ventricle, where new neurons are generated and then migrate to the olfactory bulb. Neurogenesis has been thought to occur only during the embryonic and early postnatal stages and to decline with age due to a continuous depletion of neural stem cells. Interestingly, recent years have seen tremendous progress in our understanding of adult brain neurogenesis, bridging the knowledge gap between embryonic and adult neurogenesis. Here, we discuss the current status of adult brain neurogenesis in light of what we know about neural stem cells. In this notion, we talk about the importance of intracellular signaling molecules in mobilizing endogenous neural stem cell proliferation. Based on the current understanding, we can declare that these molecules play a role in targeting neurogenesis in the mature brain. However, to achieve this goal, we need to avoid the undesired proliferation of neural stem cells by controlling the necessary checkpoints, which can lead to tumorigenesis and prove to be a curse instead of a blessing or hope.
Collapse
Affiliation(s)
- Ghulam Hussain
- Neurochemicalbiology and Genetics Laboratory (NGL), Department of Physiology, Faculty of Life Sciences, Government College University, Faisalabad, Punjab, Pakistan
| | - Rabia Akram
- Neurochemicalbiology and Genetics Laboratory (NGL), Department of Physiology, Faculty of Life Sciences, Government College University, Faisalabad, Punjab, Pakistan
| | - Haseeb Anwar
- Neurochemicalbiology and Genetics Laboratory (NGL), Department of Physiology, Faculty of Life Sciences, Government College University, Faisalabad, Punjab, Pakistan
| | - Faiqa Sajid
- Neurochemicalbiology and Genetics Laboratory (NGL), Department of Physiology, Faculty of Life Sciences, Government College University, Faisalabad, Punjab, Pakistan
| | - Tehreem Iman
- Neurochemicalbiology and Genetics Laboratory (NGL), Department of Physiology, Faculty of Life Sciences, Government College University, Faisalabad, Punjab, Pakistan
| | - Hyung Soo Han
- Department of Physiology, School of Medicine, Clinical Omics Institute, Kyungpook National University, Daegu, Korea
| | - Chand Raza
- Department of Zoology, Faculty of Chemistry and Life Sciences, Government College University, Lahore, Pakistan
| | - Jose-Luis Gonzalez De Aguilar
- INSERM, U1118, Mécanismes Centraux et Péripheriques de la Neurodégénérescence, Strasbourg, France, Université de Strasbourg, Strasbourg, France
| |
Collapse
|
2
|
Roberts LD, Hornsby AK, Thomas A, Sassi M, Kinzett A, Hsiao N, David BR, Good M, Wells T, Davies JS. The 5:2 diet does not increase adult hippocampal neurogenesis or enhance spatial memory in mice. EMBO Rep 2023; 24:e57269. [PMID: 37987211 DOI: 10.15252/embr.202357269] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2023] [Revised: 10/23/2023] [Accepted: 10/30/2023] [Indexed: 11/22/2023] Open
Abstract
New neurones are generated throughout life in the mammalian brain in a process known as adult hippocampal neurogenesis (AHN). Since this phenomenon grants a high degree of neuroplasticity influencing learning and memory, identifying factors that regulate AHN may be important for ameliorating age-related cognitive decline. Calorie restriction (CR) has been shown to enhance AHN and improve memory, mediated by the stomach hormone, ghrelin. Intermittent fasting (IF), a dietary strategy offering more flexibility than conventional CR, has also been shown to promote aspects of AHN. The 5:2 diet is a popular form of IF; however, its effects on AHN are not well characterised. To address this, we quantified AHN in adolescent and adult wild-type and ghrelin-receptor-deficient mice following 6 weeks on a 5:2 diet. We report an age-related decline in neurogenic processes. However, the 5:2 diet does not increase AHN nor enhance memory performance, suggesting that this specific form of IF is ineffective in promoting brain plasticity to support learning.
Collapse
Affiliation(s)
- Luke D Roberts
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | | | - Alanna Thomas
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Martina Sassi
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Aimee Kinzett
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Nathan Hsiao
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Bethan R David
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Mark Good
- School of Psychology, Cardiff University, Cardiff, UK
| | - Timothy Wells
- School of Biosciences, Cardiff University, Cardiff, UK
| | - Jeffrey S Davies
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| |
Collapse
|
3
|
Yun S, Soler I, Tran FH, Haas HA, Shi R, Bancroft GL, Suarez M, de Santis CR, Reynolds RP, Eisch AJ. Behavioral pattern separation and cognitive flexibility are enhanced in a mouse model of increased lateral entorhinal cortex-dentate gyrus circuit activity. Front Behav Neurosci 2023; 17:1151877. [PMID: 37324519 PMCID: PMC10267474 DOI: 10.3389/fnbeh.2023.1151877] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2023] [Accepted: 04/26/2023] [Indexed: 06/17/2023] Open
Abstract
Behavioral pattern separation and cognitive flexibility are essential cognitive abilities that are disrupted in many brain disorders. A better understanding of the neural circuitry involved in these abilities will open paths to treatment. In humans and mice, discrimination and adaptation rely on the integrity of the hippocampal dentate gyrus (DG) which receives glutamatergic input from the entorhinal cortex (EC), including the lateral EC (LEC). An inducible increase of EC-DG circuit activity improves simple hippocampal-dependent associative learning and increases DG neurogenesis. Here, we asked if the activity of LEC fan cells that directly project to the DG (LEC → DG neurons) regulates the relatively more complex hippocampal-dependent abilities of behavioral pattern separation or cognitive flexibility. C57BL/6J male mice received bilateral LEC infusions of a virus expressing shRNA TRIP8b, an auxiliary protein of an HCN channel or a control virus (SCR shRNA). Prior work shows that 4 weeks post-surgery, TRIP8b mice have more DG neurogenesis and greater activity of LEC → DG neurons compared to SCR shRNA mice. Here, 4 weeks post-surgery, the mice underwent testing for behavioral pattern separation and reversal learning (touchscreen-based location discrimination reversal [LDR]) and innate fear of open spaces (elevated plus maze [EPM]) followed by quantification of new DG neurons (doublecortin-immunoreactive cells [DCX+] cells). There was no effect of treatment (SCR shRNA vs. TRIP8b) on performance during general touchscreen training, LDR training, or the 1st days of LDR testing. However, in the last days of LDR testing, the TRIP8b shRNA mice had improved pattern separation (reached the first reversal more quickly and had more accurate discrimination) compared to the SCR shRNA mice, specifically when the load on pattern separation was high (lit squares close together or "small separation"). The TRIP8b shRNA mice were also more cognitively flexible (achieved more reversals) compared to the SCR shRNA mice in the last days of LDR testing. Supporting a specific influence on cognitive behavior, the SCR shRNA and TRIP8b shRNA mice did not differ in total distance traveled or in time spent in the closed arms of the EPM. Supporting an inducible increase in LEC-DG activity, DG neurogenesis was increased. These data indicate that the TRIP8b shRNA mice had better pattern separation and reversal learning and more neurogenesis compared to the SCR shRNA mice. This study advances fundamental and translational neuroscience knowledge relevant to two cognitive functions critical for adaptation and survival-behavioral pattern separation and cognitive flexibility-and suggests that the activity of LEC → DG neurons merits exploration as a therapeutic target to normalize dysfunctional DG behavioral output.
Collapse
Affiliation(s)
- Sanghee Yun
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| | - Ivan Soler
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States
- University of Pennsylvania, Philadelphia, PA, United States
| | - Fionya H. Tran
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Harley A. Haas
- University of Pennsylvania, Philadelphia, PA, United States
| | - Raymon Shi
- University of Pennsylvania, Philadelphia, PA, United States
| | | | - Maiko Suarez
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Christopher R. de Santis
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Ryan P. Reynolds
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States
| | - Amelia J. Eisch
- Department of Anesthesiology and Critical Care Medicine, Children's Hospital of Philadelphia, Philadelphia, PA, United States
- Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
- Department of Neuroscience and Mahoney Institute for Neurosciences, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, United States
| |
Collapse
|
4
|
Yun S, Soler I, Tran F, Haas HA, Shi R, Bancroft GL, Suarez M, de Santis CR, Reynolds RP, Eisch AJ. Behavioral pattern separation and cognitive flexibility are enhanced in a mouse model of increased lateral entorhinal cortex-dentate gyrus circuit activity. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.01.26.525756. [PMID: 36747871 PMCID: PMC9900985 DOI: 10.1101/2023.01.26.525756] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Behavioral pattern separation and cognitive flexibility are essential cognitive abilities which are disrupted in many brain disorders. Better understanding of the neural circuitry involved in these abilities will open paths to treatment. In humans and mice, discrimination and adaptation rely on integrity of the hippocampal dentate gyrus (DG) which both receive glutamatergic input from the entorhinal cortex (EC), including the lateral EC (LEC). Inducible increase of EC-DG circuit activity improves simple hippocampal-dependent associative learning and increases DG neurogenesis. Here we asked if the activity of LEC fan cells that directly project to the DG (LEC➔DG neurons) regulates behavioral pattern separation or cognitive flexibility. C57BL6/J male mice received bilateral LEC infusions of a virus expressing shRNA TRIP8b, an auxiliary protein of an HCN channel or a control virus (SCR shRNA); this approach increases the activity of LEC➔DG neurons. Four weeks later, mice underwent testing for behavioral pattern separation and reversal learning (touchscreen-based Location Discrimination Reversal [LDR] task) and innate fear of open spaces (elevated plus maze [EPM]) followed by counting of new DG neurons (doublecortin-immunoreactive cells [DCX+] cells). TRIP8b and SCR shRNA mice performed similarly in general touchscreen training and LDR training. However, in late LDR testing, TRIP8b shRNA mice reached the first reversal more quickly and had more accurate discrimination vs. SCR shRNA mice, specifically when pattern separation was challenging (lit squares close together or "small separation"). Also, TRIP8b shRNA mice achieved more reversals in late LDR testing vs. SCR shRNA mice. Supporting a specific influence on cognitive behavior, SCR shRNA and TRIP8b shRNA mice did not differ in total distance traveled or in time spent in the closed arms of the EPM. Supporting an inducible increase in LEC-DG activity, DG neurogenesis was increased. These data indicate TRIP8b shRNA mice had better pattern separation and reversal learning and more neurogenesis vs. SCR shRNA mice. This work advances fundamental and translational neuroscience knowledge relevant to two cognitive functions critical for adaptation and survival - behavioral pattern separation and cognitive flexibility - and suggests the activity of LEC➔DG neurons merits exploration as a therapeutic target to normalize dysfunctional DG behavioral output.
Collapse
|
5
|
Reich N, Hölscher C. Beyond Appetite: Acylated Ghrelin As A Learning, Memory and Fear Behavior-modulating Hormone. Neurosci Biobehav Rev 2022; 143:104952. [DOI: 10.1016/j.neubiorev.2022.104952] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2021] [Revised: 04/27/2022] [Accepted: 11/05/2022] [Indexed: 11/10/2022]
|
6
|
Ghosh-Swaby OR, Reichelt AC, Sheppard PAS, Davies J, Bussey TJ, Saksida LM. Metabolic hormones mediate cognition. Front Neuroendocrinol 2022; 66:101009. [PMID: 35679900 DOI: 10.1016/j.yfrne.2022.101009] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/23/2021] [Revised: 05/18/2022] [Accepted: 06/02/2022] [Indexed: 11/16/2022]
Abstract
Recent biochemical and behavioural evidence indicates that metabolic hormones not only regulate energy intake and nutrient content, but also modulate plasticity and cognition in the central nervous system. Disruptions in metabolic hormone signalling may provide a link between metabolic syndromes like obesity and diabetes, and cognitive impairment. For example, altered metabolic homeostasis in obesity is a strong determinant of the severity of age-related cognitive decline and neurodegenerative disease. Here we review the evidence that eating behaviours and metabolic hormones-particularly ghrelin, leptin, and insulin-are key players in the delicate regulation of neural plasticity and cognition. Caloric restriction and antidiabetic therapies, both of which affect metabolic hormone levels can restore metabolic homeostasis and enhance cognitive function. Thus, metabolic hormone pathways provide a promising target for the treatment of cognitive decline.
Collapse
Affiliation(s)
- Olivia R Ghosh-Swaby
- Schulich School of Medicine and Dentistry, Neuroscience Program, Western University, London, ON, Canada
| | - Amy C Reichelt
- Faculty of Health and Medical Sciences, Adelaide Medical School, Adelaide, Australia
| | - Paul A S Sheppard
- Schulich School of Medicine and Dentistry, Department of Physiology and Pharmacology, Western University, London, ON, Canada
| | - Jeffrey Davies
- Swansea University Medical School, Swansea University, Swansea, UK
| | - Timothy J Bussey
- Schulich School of Medicine and Dentistry, Neuroscience Program, Western University, London, ON, Canada; Schulich School of Medicine and Dentistry, Department of Physiology and Pharmacology, Western University, London, ON, Canada
| | - Lisa M Saksida
- Schulich School of Medicine and Dentistry, Neuroscience Program, Western University, London, ON, Canada; Schulich School of Medicine and Dentistry, Department of Physiology and Pharmacology, Western University, London, ON, Canada.
| |
Collapse
|
7
|
Thomas AS, Sassi M, Angelini R, Morgan AH, Davies JS. Acylation, a Conductor of Ghrelin Function in Brain Health and Disease. Front Physiol 2022; 13:831641. [PMID: 35845996 PMCID: PMC9280358 DOI: 10.3389/fphys.2022.831641] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 03/31/2022] [Indexed: 11/22/2022] Open
Abstract
Acyl-ghrelin (AG) is an orexigenic hormone that has a unique octanoyl modification on its third serine residue. It is often referred to as the “hunger hormone” due to its involvement in stimulating food intake and regulating energy homeostasis. The discovery of the enzyme ghrelin-O-acyltransferase (GOAT), which catalyses ghrelin acylation, provided further insights into the relevance of this lipidation process for the activation of the growth hormone secretagogue receptor (GHS-R) by acyl-ghrelin. Although acyl-ghrelin is predominantly linked with octanoic acid, a range of saturated fatty acids can also bind to ghrelin possibly leading to specific functions. Sources of ghrelin acylation include beta-oxidation of longer chain fatty acids, with contributions from fatty acid synthesis, the diet, and the microbiome. In addition, both acyl-ghrelin and unacyl-ghrelin (UAG) have feedback effects on lipid metabolism which in turn modulate their levels. Recently we showed that whilst acyl-ghrelin promotes adult hippocampal neurogenesis and enhances memory function, UAG inhibits these processes. As a result, we postulated that the circulating acyl-ghrelin:unacyl-ghrelin (AG:UAG) ratio might be an important regulator of neurogenesis and cognition. In this review, we discuss emerging evidence behind the relevance of ghrelin acylation in the context of brain physiology and pathology, as well as the current challenges of identifying the provenance of the acyl moiety.
Collapse
|
8
|
Sassi M, Morgan AH, Davies JS. Ghrelin Acylation-A Post-Translational Tuning Mechanism Regulating Adult Hippocampal Neurogenesis. Cells 2022; 11:cells11050765. [PMID: 35269387 PMCID: PMC8909677 DOI: 10.3390/cells11050765] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2021] [Revised: 02/11/2022] [Accepted: 02/13/2022] [Indexed: 02/05/2023] Open
Abstract
Adult hippocampal neurogenesis—the generation of new functional neurones in the adult brain—is impaired in aging and many neurodegenerative disorders. We recently showed that the acylated version of the gut hormone ghrelin (acyl-ghrelin) stimulates adult hippocampal neurogenesis while the unacylated form of ghrelin inhibits it, thus demonstrating a previously unknown function of unacyl-ghrelin in modulating hippocampal plasticity. Analysis of plasma samples from Parkinson’s disease patients with dementia demonstrated a reduced acyl-ghrelin:unacyl-ghrelin ratio compared to both healthy controls and cognitively intact Parkinson’s disease patients. These data, from mouse and human studies, suggest that restoring acyl-ghrelin signalling may promote the activation of pathways to support memory function. In this short review, we discuss the evidence for ghrelin’s role in regulating adult hippocampal neurogenesis and the enzymes involved in ghrelin acylation and de-acylation as targets to treat mood-related disorders and dementia.
Collapse
|
9
|
Giorgioni G, Del Bello F, Quaglia W, Botticelli L, Cifani C, Micioni Di Bonaventura E, Micioni Di Bonaventura MV, Piergentili A. Advances in the Development of Nonpeptide Small Molecules Targeting Ghrelin Receptor. J Med Chem 2022; 65:3098-3118. [PMID: 35157454 PMCID: PMC8883476 DOI: 10.1021/acs.jmedchem.1c02191] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022]
Abstract
Ghrelin is an octanoylated peptide acting by the activation of the growth hormone secretagogue receptor, namely, GHS-R1a. The involvement of ghrelin in several physiological processes, including stimulation of food intake, gastric emptying, body energy balance, glucose homeostasis, reduction of insulin secretion, and lipogenesis validates the considerable interest in GHS-R1a as a promising target for the treatment of numerous disorders. Over the years, several GHS-R1a ligands have been identified and some of them have been extensively studied in clinical trials. The recently resolved structures of GHS-R1a bound to ghrelin or potent ligands have provided useful information for the design of new GHS-R1a drugs. This perspective is focused on the development of recent nonpeptide small molecules acting as GHS-R1a agonists, antagonists, and inverse agonists, bearing classical or new molecular scaffolds, as well as on radiolabeled GHS-R1a ligands developed for imaging. Moreover, the pharmacological effects of the most studied ligands have been discussed.
Collapse
Affiliation(s)
- Gianfabio Giorgioni
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, Via Madonna delle Carceri, 62032 Camerino, Italy
| | - Fabio Del Bello
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, Via Madonna delle Carceri, 62032 Camerino, Italy
| | - Wilma Quaglia
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, Via Madonna delle Carceri, 62032 Camerino, Italy
| | - Luca Botticelli
- School of Pharmacy, Pharmacology Unit, University of Camerino, Via Madonna delle Carceri 9, 62032 Camerino, Italy
| | - Carlo Cifani
- School of Pharmacy, Pharmacology Unit, University of Camerino, Via Madonna delle Carceri 9, 62032 Camerino, Italy
| | - E Micioni Di Bonaventura
- School of Pharmacy, Pharmacology Unit, University of Camerino, Via Madonna delle Carceri 9, 62032 Camerino, Italy
| | - M V Micioni Di Bonaventura
- School of Pharmacy, Pharmacology Unit, University of Camerino, Via Madonna delle Carceri 9, 62032 Camerino, Italy
| | - Alessandro Piergentili
- School of Pharmacy, Medicinal Chemistry Unit, University of Camerino, Via Madonna delle Carceri, 62032 Camerino, Italy
| |
Collapse
|
10
|
Abstract
The stomach hormone, ghrelin, which is released during food restriction, provides a link between circulating energy state and adaptive brain function. The maintenance of such homeostatic systems is essential for an organism to survive and thrive, and accumulating evidence points to ghrelin being a key regulator of adult hippocampal neurogenesis and memory function. Aberrant neurogenesis is linked to cognitive decline in aging and neurodegeneration. Therefore, identifying endogenous metabolic factors that regulate new adult-born neuron formation is an important objective in understanding the link between nutritional status and CNS function. Here, we review current developments in our understanding of ghrelin's role in regulating neurogenesis and memory function.
Collapse
Affiliation(s)
- Jeffrey S Davies
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, United Kingdom.
| |
Collapse
|
11
|
Farzin M, Babaei P, Rostampour M. Intrahippocampal Injections of Ghrelin and Aerobic Physical Exercise: Effects on Learning and Passive Avoidance Memory in Rats. NEUROPHYSIOLOGY+ 2021. [DOI: 10.1007/s11062-021-09912-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/19/2022]
|
12
|
The spontaneous location recognition task for assessing spatial pattern separation and memory across a delay in rats and mice. Nat Protoc 2021; 16:5616-5633. [PMID: 34741153 DOI: 10.1038/s41596-021-00627-w] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2020] [Accepted: 09/02/2021] [Indexed: 11/08/2022]
Abstract
Keeping similar memories distinct from one another is a critical cognitive process without which we would have difficulty functioning in everyday life. Memories are thought to be kept distinct through the computational mechanism of pattern separation, which reduces overlap between similar input patterns to amplify differences among stored representations. At the behavioral level, impaired pattern separation has been shown to contribute to memory deficits seen in neuropsychiatric and neurodegenerative diseases, including Alzheimer's disease, and in normal aging. This protocol describes the use of the spontaneous location recognition (SLR) task in mice and rats to behaviorally assess spatial pattern separation ability. This two-phase spontaneous memory task assesses the extent to which animals can discriminate and remember object locations presented during the encoding phase. Using three configurations of the task, the similarity of the to-be-remembered locations can be parametrically manipulated by altering the spatial positions of objects-dissimilar, similar or extra similar-to vary the load on pattern separation. Unlike other pattern separation tasks, SLR varies the load on pattern separation during encoding, when pattern separation is thought to occur. Furthermore, SLR can be used in standard rodent behavioral facilities with basic expertise in rodent handling. The entire protocol takes ~20 d from habituation to testing of the animals on all three task configurations. By incorporating breaks between testing, and varying the objects used as landmarks, animals can be tested repeatedly, increasing experimental power by allowing for within-subjects manipulations.
Collapse
|
13
|
Ronchi G, Tos P, Angelino E, Muratori L, Reano S, Filigheddu N, Graziani A, Geuna S, Raimondo S. Effect of unacylated ghrelin on peripheral nerve regeneration. Eur J Histochem 2021; 65. [PMID: 34734521 PMCID: PMC8586818 DOI: 10.4081/ejh.2021.3287] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2021] [Accepted: 08/13/2021] [Indexed: 11/28/2022] Open
Abstract
Ghrelin is a circulating peptide hormone released by enteroendocrine cells of the gastrointestinal tract as two forms, acylated and unacylated. Acylated ghrelin (AG) binds to the growth hormone secretagogue receptor 1a (GHSR1a), thus stimulating food intake, growth hormone release, and gastrointestinal motility. Conversely, unacylated GHR (UnAG), through binding to a yet unidentified receptor, protects the skeletal muscle from atrophy, stimulates muscle regeneration, and protects cardiomyocytes from ischemic damage. Recently, interest about ghrelin has raised also among neuroscientists because of its effect on the nervous system, especially the stimulation of neurogenesis in spinal cord, brain stem, and hippocampus. However, few information is still available about its effectiveness on peripheral nerve regeneration. To partially fill this gap, the aim of this study was to assess the effect of UnAG on peripheral nerve regeneration after median nerve crush injury and after nerve transection immediately repaired by means of an end-to-end suture. To this end, we exploited FVB1 Myh6/Ghrl transgenic mice in which overexpression of the ghrelin gene (Ghrl) results in selective up-regulation of circulating UnAG levels, but not of AG. Regeneration was assessed by both functional evaluation (grasping test) and morphometrical analysis of regenerated myelinated axons. Results obtained lead to conclude that UnAG could have a role in development of peripheral nerves and during more severe lesions.
Collapse
Affiliation(s)
- Giulia Ronchi
- Department of Clinical and Biological Sciences and Neuroscience Institute of the "Cavalieri Ottolenghi" Foundation (NICO), University of Turin, Orbassano (TO).
| | - Pierluigi Tos
- Hand Surgery and Reconstructive Microsurgery Unit, ASST G. Pini-CTO, Milan.
| | - Elia Angelino
- Department of Biotechnologies and Health Sciences, Molecular Biotechnology Center, University of Turin.
| | - Luisa Muratori
- Department of Clinical and Biological Sciences and Neuroscience Institute of the "Cavalieri Ottolenghi" Foundation (NICO), University of Turin, Orbassano (TO).
| | - Simone Reano
- Department of Translational Medicine, University of Piemonte Orientale, Novara.
| | | | - Andrea Graziani
- Department of Biotechnologies and Health Sciences, Molecular Biotechnology Center, University of Turin.
| | - Stefano Geuna
- Department of Clinical and Biological Sciences and Neuroscience Institute of the "Cavalieri Ottolenghi" Foundation (NICO), University of Turin, Orbassano (TO).
| | - Stefania Raimondo
- Department of Clinical and Biological Sciences and Neuroscience Institute of the "Cavalieri Ottolenghi" Foundation (NICO), University of Turin, Orbassano (TO).
| |
Collapse
|
14
|
Berdugo-Vega G, Lee CC, Garthe A, Kempermann G, Calegari F. Adult-born neurons promote cognitive flexibility by improving memory precision and indexing. Hippocampus 2021; 31:1068-1079. [PMID: 34174010 DOI: 10.1002/hipo.23373] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 05/26/2021] [Accepted: 06/06/2021] [Indexed: 11/12/2022]
Abstract
Adult neurogenesis in the hippocampal dentate gyrus (DG) is an extraordinary form of plasticity fundamental for cognitive flexibility. Recent evidence showed that newborn neurons differentially modulate input to the infra- and supra-pyramidal blades of the DG during the processing of spatial and contextual information, respectively. However, how this differential regulation by neurogenesis is translated into different aspects contributing cognitive flexibility is unclear. Here, we increased adult-born neurons by a genetic expansion of neural stem cells and studied their influence during navigational learning. We found that increased neurogenesis improved both memory precision and flexibility. Interestingly, each of these gains was associated with distinct subregional patterns of activity and better separation of memory representations in the DG-CA3 network. Our results highlight the role of adult-born neurons in promoting memory precision and indexing and suggests their anatomical allocation within specific DG-CA3 compartments, together contributing to cognitive flexibility.
Collapse
Affiliation(s)
- Gabriel Berdugo-Vega
- CRTD-Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
| | - Chi-Chieh Lee
- CRTD-Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
| | - Alexander Garthe
- CRTD-Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany.,DZNE-German Center for Neurodegenerative Diseases, Dresden, Germany
| | - Gerd Kempermann
- CRTD-Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany.,DZNE-German Center for Neurodegenerative Diseases, Dresden, Germany
| | - Federico Calegari
- CRTD-Center for Regenerative Therapies Dresden, Technische Universität Dresden, Dresden, Germany
| |
Collapse
|
15
|
Stoyanova I, Lutz D. Ghrelin-Mediated Regeneration and Plasticity After Nervous System Injury. Front Cell Dev Biol 2021; 9:595914. [PMID: 33869167 PMCID: PMC8046019 DOI: 10.3389/fcell.2021.595914] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 02/24/2021] [Indexed: 12/17/2022] Open
Abstract
The nervous system is highly vulnerable to different factors which may cause injury followed by an acute or chronic neurodegeneration. Injury involves a loss of extracellular matrix integrity, neuronal circuitry disintegration, and impairment of synaptic activity and plasticity. Application of pleiotropic molecules initiating extracellular matrix reorganization and stimulating neuronal plasticity could prevent propagation of the degeneration into the tissue surrounding the injury. To find an omnipotent therapeutic molecule, however, seems to be a fairly ambitious task, given the complex demands of the regenerating nervous system that need to be fulfilled. Among the vast number of candidates examined so far, the neuropeptide and hormone ghrelin holds within a very promising therapeutic potential with its ability to cross the blood-brain barrier, to balance metabolic processes, and to stimulate neurorepair and neuroactivity. Compared with its well-established systemic effects in treatment of metabolism-related disorders, the therapeutic potential of ghrelin on neuroregeneration upon injury has received lesser appreciation though. Here, we discuss emerging concepts of ghrelin as an omnipotent player unleashing developmentally related molecular cues and morphogenic cascades, which could attenuate and/or counteract acute and chronic neurodegeneration.
Collapse
Affiliation(s)
- Irina Stoyanova
- Department of Anatomy and Cell Biology, Medical University Varna, Varna, Bulgaria
| | - David Lutz
- Department of Neuroanatomy and Molecular Brain Research, Ruhr University Bochum, Bochum, Germany
| |
Collapse
|
16
|
Ghrelin peptide improves glial conditioned medium effects on neuronal differentiation of human adipose mesenchymal stem cells. Histochem Cell Biol 2021; 156:35-46. [PMID: 33728539 PMCID: PMC8277640 DOI: 10.1007/s00418-021-01980-3] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/01/2021] [Indexed: 12/20/2022]
Abstract
The influences of ghrelin on neural differentiation of adipose-derived mesenchymal stem cells (ASCs) were investigated in this study. The expression of typical neuronal markers, such as protein gene product 9.5 (PGP9.5) and Microtubule Associated Protein 2 (MAP2), as well as glial Fibrillary Acid Protein (GFAP) as a glial marker was evaluated in ASCs in different conditions. In particular, 2 µM ghrelin was added to control ASCs and to ASCs undergoing neural differentiation. For this purpose, ASCs were cultured in Conditioned Media obtained from Olfactory Ensheathing cells (OEC-CM) or from Schwann cells (SC-CM). Data on marker expression were gathered after 1 and 7 days of culture by fluorescence immunocytochemistry and flow cytometry. Results show that only weak effects were induced by the addition of only ghrelin. Instead, dynamic ghrelin-induced modifications were detected on the increased marker expression elicited by glial conditioned media. In fact, the combination of ghrelin and conditioned media consistently induced a further increase of PGP9.5 and MAP2 expression, especially after 7 days of treatment. The combination of ghrelin with SC-CM produced the most evident effects. Weak or no modifications were found on conditioned medium-induced GFAP increases. Observations on the ghrelin receptor indicate that its expression in control ASCs, virtually unchanged by the addition of only ghrelin, was considerably increased by CM treatment. These increases were enhanced by combining ghrelin and CM treatment, especially at 7 days. Overall, it can be assumed that ghrelin favors a neuronal rather than a glial ASC differentiation.
Collapse
|
17
|
Gilchrist CP, Cumberland AL, Kondos-Devcic D, Hill RA, Khore M, Quezada S, Reichelt AC, Tolcos M. Hippocampal neurogenesis and memory in adolescence following intrauterine growth restriction. Hippocampus 2020; 31:321-334. [PMID: 33320965 DOI: 10.1002/hipo.23291] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Revised: 10/18/2020] [Accepted: 11/15/2020] [Indexed: 12/11/2022]
Abstract
Intrauterine growth restriction (IUGR) is associated with hippocampal alterations that can increase the risk of short-term memory impairments later in life. Despite the role of hippocampal neurogenesis in learning and memory, research into the long-lasting impact of IUGR on these processes is limited. We aimed to determine the effects of IUGR on neuronal proliferation, differentiation and morphology, and on memory function at adolescent equivalent age. At embryonic day (E) 18 (term ∼E22), placental insufficiency was induced in pregnant Wistar rats via bilateral uterine vessel ligation to generate IUGR offspring (n = 10); control offspring (n = 11) were generated via sham surgery. From postnatal day (P) 36-44, spontaneous location recognition (SLR), novel object location and recognition (NOL, NOR), and open field tests were performed. Brains were collected at P45 to assess neurogenesis (immunohistochemistry), dendritic morphology (Golgi staining), and brain-derived neurotrophic factor expression (BDNF; Western blot analysis). In IUGR versus control rats there was no difference in object preference in the NOL or NOR, the similar and dissimilar condition of the SLR task, or in locomotion and anxiety-like behavior in the open field. There was a significant increase in the linear density of immature neurons (DCX+) in the subgranular zone (SGZ) of the dentate gyrus (DG), but no difference in the linear density of proliferating cells (Ki67+) in the SGZ, nor in areal density of mature neurons (NeuN+) or microglia (Iba-1+) in the DG in IUGR rats compared to controls. Dendritic morphology of dentate granule cells did not differ between groups. Protein expression of the BDNF precursor (pro-BDNF), but not mature BDNF, was increased in the hippocampus of IUGR compared with control rats. These findings highlight that while the long-lasting prenatal hypoxic environment may impact brain development, it may not impact hippocampal-dependent learning and memory in adolescence.
Collapse
Affiliation(s)
- Courtney P Gilchrist
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Angela L Cumberland
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Delphi Kondos-Devcic
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Rachel A Hill
- Department of Psychiatry, Monash University, Clayton, Victoria, Australia
| | - Madhavi Khore
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Sebastian Quezada
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| | - Amy C Reichelt
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia.,Florey Institute of Neuroscience and Mental Health, Parkville, Victoria, Australia.,Schulich School of Medicine and Dentistry, Western University, London, Ontario, Canada
| | - Mary Tolcos
- School of Health and Biomedical Sciences, RMIT University, Bundoora, Victoria, Australia
| |
Collapse
|
18
|
Reich N, Hölscher C. Acylated Ghrelin as a Multi-Targeted Therapy for Alzheimer's and Parkinson's Disease. Front Neurosci 2020; 14:614828. [PMID: 33381011 PMCID: PMC7767977 DOI: 10.3389/fnins.2020.614828] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2020] [Accepted: 11/27/2020] [Indexed: 12/13/2022] Open
Abstract
Much thought has been given to the impact of Amyloid Beta, Tau and Alpha-Synuclein in the development of Alzheimer's disease (AD) and Parkinson's disease (PD), yet the clinical failures of the recent decades indicate that there are further pathological mechanisms at work. Indeed, besides amyloids, AD and PD are characterized by the culminative interplay of oxidative stress, mitochondrial dysfunction and hyperfission, defective autophagy and mitophagy, systemic inflammation, BBB and vascular damage, demyelination, cerebral insulin resistance, the loss of dopamine production in PD, impaired neurogenesis and, of course, widespread axonal, synaptic and neuronal degeneration that leads to cognitive and motor impediments. Interestingly, the acylated form of the hormone ghrelin has shown the potential to ameliorate the latter pathologic changes, although some studies indicate a few complications that need to be considered in the long-term administration of the hormone. As such, this review will illustrate the wide-ranging neuroprotective properties of acylated ghrelin and critically evaluate the hormone's therapeutic benefits for the treatment of AD and PD.
Collapse
Affiliation(s)
- Niklas Reich
- Biomedical & Life Sciences Division, Lancaster University, Lancaster, United Kingdom
| | - Christian Hölscher
- Neurology Department, A Second Hospital, Shanxi Medical University, Taiyuan, China.,Research and Experimental Center, Henan University of Chinese Medicine, Zhengzhou, China
| |
Collapse
|
19
|
Hornsby AK, Buntwal L, Carisi MC, Santos VV, Johnston F, Roberts LD, Sassi M, Mequinion M, Stark R, Reichenbach A, Lockie SH, Siervo M, Howell O, Morgan AH, Wells T, Andrews ZB, Burn DJ, Davies JS. Unacylated-Ghrelin Impairs Hippocampal Neurogenesis and Memory in Mice and Is Altered in Parkinson's Dementia in Humans. CELL REPORTS MEDICINE 2020; 1:100120. [PMID: 33103129 PMCID: PMC7575905 DOI: 10.1016/j.xcrm.2020.100120] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Revised: 05/20/2020] [Accepted: 09/16/2020] [Indexed: 12/20/2022]
Abstract
Blood-borne factors regulate adult hippocampal neurogenesis and cognition in mammals. We report that elevating circulating unacylated-ghrelin (UAG), using both pharmacological and genetic methods, reduced hippocampal neurogenesis and plasticity in mice. Spatial memory impairments observed in ghrelin-O-acyl transferase-null (GOAT−/−) mice that lack acyl-ghrelin (AG) but have high levels of UAG were rescued by acyl-ghrelin. Acyl-ghrelin-mediated neurogenesis in vitro was dependent on non-cell-autonomous BDNF signaling that was inhibited by UAG. These findings suggest that post-translational acylation of ghrelin is important to neurogenesis and memory in mice. To determine relevance in humans, we analyzed circulating AG:UAG in Parkinson disease (PD) patients diagnosed with dementia (PDD), cognitively intact PD patients, and controls. Notably, plasma AG:UAG was only reduced in PDD. Hippocampal ghrelin-receptor expression remained unchanged; however, GOAT+ cell number was reduced in PDD. We identify UAG as a regulator of hippocampal-dependent plasticity and spatial memory and AG:UAG as a putative circulating diagnostic biomarker of dementia. Circulating unacylated-ghrelin (UAG) reduces hippocampal neurogenesis Circulating acyl-ghrelin (AG) rescues spatial memory deficit in GOAT−/− mice UAG blocks the AG induced survival of newborn hippocampal cells Plasma AG:UAG and hippocampal GOAT+ cells are reduced in Parkinson’s dementia
Collapse
Affiliation(s)
- Amanda K.E. Hornsby
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Luke Buntwal
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Maria Carla Carisi
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Vanessa V. Santos
- Biomedical Discovery Institute, Department of Physiology, Monash University, Clayton, VIC, Australia
| | - Fionnuala Johnston
- Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Luke D. Roberts
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Martina Sassi
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Mathieu Mequinion
- Biomedical Discovery Institute, Department of Physiology, Monash University, Clayton, VIC, Australia
| | - Romana Stark
- Biomedical Discovery Institute, Department of Physiology, Monash University, Clayton, VIC, Australia
| | - Alex Reichenbach
- Biomedical Discovery Institute, Department of Physiology, Monash University, Clayton, VIC, Australia
| | - Sarah H. Lockie
- Biomedical Discovery Institute, Department of Physiology, Monash University, Clayton, VIC, Australia
| | - Mario Siervo
- Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
- School of Life Sciences, Queen's Medical Centre, The University of Nottingham Medical School, Nottingham NG7 2UH, UK
| | - Owain Howell
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Alwena H. Morgan
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Timothy Wells
- School of Biosciences, Cardiff University, Cardiff, UK
| | - Zane B. Andrews
- Biomedical Discovery Institute, Department of Physiology, Monash University, Clayton, VIC, Australia
| | - David J. Burn
- Faculty of Medical Sciences, Newcastle University, Newcastle upon Tyne, UK
| | - Jeffrey S. Davies
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
- Corresponding author
| |
Collapse
|
20
|
Russo C, Patanè M, Russo A, Stanzani S, Pellitteri R. Effects of Ghrelin on Olfactory Ensheathing Cell Viability and Neural Marker Expression. J Mol Neurosci 2020; 71:963-971. [PMID: 32978692 DOI: 10.1007/s12031-020-01716-3] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Accepted: 09/21/2020] [Indexed: 01/19/2023]
Abstract
Ghrelin (Ghre), a gut-brain peptide hormone, plays an important role in the entire olfactory system and in food behavior regulation. In the last years, it has aroused particular interest for its antioxidant, anti-inflammatory, and anti-apoptotic properties. Our previous research showed that Ghre and its receptor are expressed by peculiar glial cells of the olfactory system: Olfactory Ensheathing Cells (OECs). These cells are able to secrete different neurotrophic factors, promote axonal growth, and show stem cell characteristics. The aim of this work was to study, in an in vitro model, the effect of Ghre on both cell viability and the expression of some neural markers, such as Nestin (Ne), Glial Fibrillary Acid Protein (GFAP), Neuregulin (Neu), and β-III-tubulin (Tuj1), in primary mouse OEC cultures. The MTT test and immunocytochemical procedures were used to highlight cell viability and marker expression, respectively. Our results demonstrate that Ghre, after 7 days of treatment, exerted a positive effect, stimulating OEC viability compared with cells without Ghre treatment. In addition, Ghre was able to modify the expression of some biomarkers, increasing Neu and Tuj1 expression, while GFAP was constant; on the contrary, the presence of positive Ne cells was drastically reduced after 7 days, and this showed a loss of stem cell characteristic and therefore the possible orientation towards an adult neural phenotype.
Collapse
Affiliation(s)
- Cristina Russo
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, 95123, Catania, Italy
| | - Martina Patanè
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, 95123, Catania, Italy
| | - Antonella Russo
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, 95123, Catania, Italy
| | - Stefania Stanzani
- Department of Biomedical and Biotechnological Sciences, Section of Physiology, University of Catania, 95123, Catania, Italy
| | - Rosalia Pellitteri
- Institute for Biomedical Research and Innovation, National Research Council, 95126, Catania, Italy.
| |
Collapse
|
21
|
Zhang F, Xu F, Mi X, Dong L, Xiao Y, Jiang S, Li GD, Zhou Y. Ghrelin/GHS-R1a signaling plays different roles in anxiety-related behaviors after acute and chronic caloric restriction. Biochem Biophys Res Commun 2020; 529:1131-1136. [PMID: 32819576 DOI: 10.1016/j.bbrc.2020.05.227] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/19/2020] [Accepted: 05/31/2020] [Indexed: 12/31/2022]
Abstract
The brain-gut hormone ghrelin and its receptor GHS-R1a, the growth hormone secretagogue receptor 1a, regulates diverse functions of central nervous system including stress response and mood. Both acute and chronic caloric restrictions (CR) were reported to increase endogenous ghrelin level meanwhile regulate anxiety-related behaviors; however, the causal relationship between CR-induced ghrelin elevation and anxiety are not fully established. Here, we introduced an acute (24 h) and a chronic (10wks) CR procedure to both GHS-R1a KO (Ghsr-/-) mice and WT (Ghsr+/+) littermates, and compared their anxiety-related behaviors. We found that acute CR induced anxiolytic and anti-despairing behaviors in Ghsr+/+ mice but not in Ghsr-/- mice. Ad-libitum refeeding abolished the effect of acute CR on anxiety-related behaviors. In contrast, chronic CR for 10wks facilitated despair-like behavior meanwhile inhibited anxiety-like behavior in Ghsr+/+ mice. GHS-R1a deficiency rescued despair-like behavior while did not affect anxiolytic response induced by chronic CR. In addition, we found elevated interleukin-6 (IL-6) in serum of Ghsr+/+ mice after chronic CR, but not in Ghsr-/- mice. Altogether, our findings indicated that acute CR and chronic CR have different impacts on anxiety-related behaviors, and the former is dependent on ghrelin/GHS-R1a signaling while the latter may not always be. In addition, our findings suggested that GHS-R1a-dependent elevation in serum IL-6 might contribute to increased despair-like behavior in chronic CR state.
Collapse
Affiliation(s)
- Fengyi Zhang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao, Shandong, 266071, China
| | - Fenghua Xu
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao, Shandong, 266071, China
| | - Xue Mi
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao, Shandong, 266071, China
| | - Linfei Dong
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao, Shandong, 266071, China
| | - Yuhao Xiao
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao, Shandong, 266071, China
| | - Shibang Jiang
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao, Shandong, 266071, China
| | - Guo-Dong Li
- GUODONG LI MD Practice, Beverly Hills, California, 90211, USA
| | - Yu Zhou
- Department of Physiology and Pathophysiology, School of Basic Medical Sciences, Qingdao University, Qingdao, Shandong, 266071, China; Institute of Brain Sciences and Related Disorders, Qingdao University, Qingdao, Shandong, 266071, China.
| |
Collapse
|
22
|
Autio J, Stenbäck V, Gagnon DD, Leppäluoto J, Herzig KH. (Neuro) Peptides, Physical Activity, and Cognition. J Clin Med 2020; 9:jcm9082592. [PMID: 32785144 PMCID: PMC7464334 DOI: 10.3390/jcm9082592] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/03/2020] [Revised: 07/31/2020] [Accepted: 08/06/2020] [Indexed: 02/06/2023] Open
Abstract
Regular physical activity (PA) improves cognitive functions, prevents brain atrophy, and delays the onset of cognitive decline, dementia, and Alzheimer’s disease. Presently, there are no specific recommendations for PA producing positive effects on brain health and little is known on its mediators. PA affects production and release of several peptides secreted from peripheral and central tissues, targeting receptors located in the central nervous system (CNS). This review will provide a summary of the current knowledge on the association between PA and cognition with a focus on the role of (neuro)peptides. For the review we define peptides as molecules with less than 100 amino acids and exclude myokines. Tachykinins, somatostatin, and opioid peptides were excluded from this review since they were not affected by PA. There is evidence suggesting that PA increases peripheral insulin growth factor 1 (IGF-1) levels and elevated serum IGF-1 levels are associated with improved cognitive performance. It is therefore likely that IGF-1 plays a role in PA induced improvement of cognition. Other neuropeptides such as neuropeptide Y (NPY), ghrelin, galanin, and vasoactive intestinal peptide (VIP) could mediate the beneficial effects of PA on cognition, but the current literature regarding these (neuro)peptides is limited.
Collapse
Affiliation(s)
- Juho Autio
- Institute of Biomedicine, Medical Research Center, Faculty of Medicine, University of Oulu, Oulu University Hospital, 90220 Oulu, Finland; (J.A.); (V.S.); (D.D.G.); (J.L.)
| | - Ville Stenbäck
- Institute of Biomedicine, Medical Research Center, Faculty of Medicine, University of Oulu, Oulu University Hospital, 90220 Oulu, Finland; (J.A.); (V.S.); (D.D.G.); (J.L.)
- Biocenter Oulu, 90220 Oulu, Finland
| | - Dominique D. Gagnon
- Institute of Biomedicine, Medical Research Center, Faculty of Medicine, University of Oulu, Oulu University Hospital, 90220 Oulu, Finland; (J.A.); (V.S.); (D.D.G.); (J.L.)
- Laboratory of Environmental Exercise Physiology, School of Human Kinetics, Laurentian University, Sudbury, ON P3E 2C6, Canada
- Center of Research in Occupational Safety and Health, Laurentian University, Sudbury, ON P3E 2C6, Canada
| | - Juhani Leppäluoto
- Institute of Biomedicine, Medical Research Center, Faculty of Medicine, University of Oulu, Oulu University Hospital, 90220 Oulu, Finland; (J.A.); (V.S.); (D.D.G.); (J.L.)
| | - Karl-Heinz Herzig
- Institute of Biomedicine, Medical Research Center, Faculty of Medicine, University of Oulu, Oulu University Hospital, 90220 Oulu, Finland; (J.A.); (V.S.); (D.D.G.); (J.L.)
- Department of Gastroenterology and Metabolism, Poznan University of Medical Sciences, 60-572 Poznan, Poland
- Correspondence:
| |
Collapse
|
23
|
Buntwal L, Sassi M, Morgan AH, Andrews ZB, Davies JS. Ghrelin-Mediated Hippocampal Neurogenesis: Implications for Health and Disease. Trends Endocrinol Metab 2019; 30:844-859. [PMID: 31445747 DOI: 10.1016/j.tem.2019.07.001] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2019] [Revised: 06/21/2019] [Accepted: 07/08/2019] [Indexed: 12/13/2022]
Abstract
There is a close relationship between cognition and nutritional status, however, the mechanisms underlying this relationship require elucidation. The stomach hormone, ghrelin, which is released during food restriction, provides a link between circulating energy state and adaptive brain function. The maintenance of such homeostatic systems is essential for an organism to thrive and survive, and accumulating evidence points to ghrelin being key in promoting adult hippocampal neurogenesis and memory. Aberrant neurogenesis is linked to cognitive decline in ageing and neurodegeneration. Therefore, identifying endogenous metabolic factors that regulate new adult-born neurone formation is an important objective in understanding the link between nutritional status and central nervous system (CNS) function. Here, we review current developments in our understanding of ghrelin's role in regulating neurogenesis and memory function.
Collapse
Affiliation(s)
- Luke Buntwal
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, SA2 8PP, UK
| | - Martina Sassi
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, SA2 8PP, UK
| | - Alwena H Morgan
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, SA2 8PP, UK
| | - Zane B Andrews
- Department of Physiology, Biomedical Discovery Unit, Monash University, Melbourne, Australia
| | - Jeffrey S Davies
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, SA2 8PP, UK.
| |
Collapse
|
24
|
Acute But Not Chronic Calorie Restriction Defends against Stress-Related Anxiety and Despair in a GHS-R1a-Dependent Manner. Neuroscience 2019; 412:94-104. [DOI: 10.1016/j.neuroscience.2019.05.067] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/17/2019] [Revised: 05/30/2019] [Accepted: 05/31/2019] [Indexed: 12/27/2022]
|
25
|
Dong D, Xie J, Wang J. Neuroprotective Effects of Brain-Gut Peptides: A Potential Therapy for Parkinson's Disease. Neurosci Bull 2019; 35:1085-1096. [PMID: 31286411 DOI: 10.1007/s12264-019-00407-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/06/2019] [Accepted: 04/29/2019] [Indexed: 12/16/2022] Open
Abstract
Parkinson's disease (PD) is the second most common neurodegenerative disease and is typically associated with progressive motor and non-motor dysfunctions. Currently, dopamine replacement therapy is mainly used to relieve the motor symptoms, while its long-term application can lead to various complications and does not cure the disease. Numerous studies have demonstrated that many brain-gut peptides have neuroprotective effects in vivo and in vitro, and may be a promising treatment for PD. In recent years, some progress has been made in studies on the neuroprotective effects of some newly-discovered brain-gut peptides, such as glucagon-like peptide 1, pituitary adenylate cyclase activating polypeptide, nesfatin-1, and ghrelin. However, there is still no systematic review on the neuroprotective effects common to these peptides. Thus, here we review the neuroprotective effects and the associated mechanisms of these four peptides, as well as other brain-gut peptides related to PD, in the hope of providing new ideas for the treatment of PD and related clinical research.
Collapse
Affiliation(s)
- Dong Dong
- Department of Physiology and Pathophysiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, 266071, China
| | - Junxia Xie
- Department of Physiology and Pathophysiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, 266071, China.
| | - Jun Wang
- Department of Physiology and Pathophysiology, Shandong Provincial Key Laboratory of Pathogenesis and Prevention of Neurological Disorders, Shandong Provincial Collaborative Innovation Center for Neurodegenerative Disorders and State Key Disciplines: Physiology, Medical College of Qingdao University, Qingdao, 266071, China.
| |
Collapse
|
26
|
Lockie SH, Stark R, Spanswick DC, Andrews ZB. Glucose availability regulates ghrelin-induced food intake in the ventral tegmental area. J Neuroendocrinol 2019; 31:e12696. [PMID: 30742723 DOI: 10.1111/jne.12696] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/19/2018] [Revised: 12/13/2018] [Accepted: 02/08/2019] [Indexed: 12/23/2022]
Abstract
Information about metabolic status arrives in the brain in the form of a complex milieu of circulating signalling factors, including glucose and fatty acids, ghrelin, leptin and insulin. The specific interactions between humoural factors, brain sites of action and how they influence behaviour are largely unknown. We have previously observed interactions between glucose availability and the actions of ghrelin mediated via the agouti-related peptide neurones of the hypothalamus. In the present study, we examine whether these effects generalise to another ghrelin-sensitive brain nucleus, the ventral tegmental area (VTA). We altered glucose availability by injecting mice with glucose or 2-deoxyglucose i.p. to induce hyperglycaemia and glucopenia, respectively. Thirty minutes later, we injected ghrelin in the VTA. Glucose administration suppressed intra-VTA ghrelin-induced feeding. Leptin, a longer-term signal of positive energy balance, did not affect intra-VTA ghrelin-induced feeding. 2-Deoxyglucose and ghrelin both increased food intake in their own right and, together, they additively increased feeding. These results add support to the idea that calculation of metabolic need depends on multiple signals across multiple brain regions and identifies that VTA circuits are sensitive to the integration of signals reflecting internal homeostatic state and influencing food intake.
Collapse
Affiliation(s)
- Sarah H Lockie
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Romana Stark
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - David C Spanswick
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| |
Collapse
|
27
|
Ratcliff M, Rees D, McGrady S, Buntwal L, Hornsby AKE, Bayliss J, Kent BA, Bussey T, Saksida L, Beynon AL, Howell OW, Morgan AH, Sun Y, Andrews ZB, Wells T, Davies JS. Calorie restriction activates new adult born olfactory-bulb neurones in a ghrelin-dependent manner but acyl-ghrelin does not enhance subventricular zone neurogenesis. J Neuroendocrinol 2019; 31:e12755. [PMID: 31179562 DOI: 10.1111/jne.12755] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/07/2018] [Revised: 06/06/2019] [Accepted: 06/06/2019] [Indexed: 12/25/2022]
Abstract
The ageing and degenerating brain show deficits in neural stem/progenitor cell (NSPC) plasticity that are accompanied by impairments in olfactory discrimination. Emerging evidence suggests that the gut hormone ghrelin plays an important role in protecting neurones, promoting synaptic plasticity and increasing hippocampal neurogenesis in the adult brain. In the present study, we investigated the role of ghrelin with respect to modulating adult subventricular zone (SVZ) NSPCs that give rise to new olfactory bulb (OB) neurones. We characterised the expression of the ghrelin receptor, growth hormone secretagogue receptor (GHSR), using an immunohistochemical approach in GHSR-eGFP reporter mice to show that GHSR is expressed in several regions, including the OB but not in the SVZ of the lateral ventricle. These data suggest that acyl-ghrelin does not mediate a direct effect on NSPC in the SVZ. Consistent with these findings, treatment with acyl-ghrelin or genetic silencing of GHSR did not alter NSPC proliferation within the SVZ. Similarly, using a bromodeoxyuridine pulse-chase approach, we show that peripheral treatment of adult rats with acyl-ghrelin did not increase the number of new adult-born neurones in the granule cell layer of the OB. These data demonstrate that acyl-ghrelin does not increase adult OB neurogenesis. Finally, we investigated whether elevating ghrelin indirectly, via calorie restriction (CR), regulated the activity of new adult-born cells in the OB. Overnight CR induced c-Fos expression in new adult-born OB cells but not in developmentally born cells, whereas neuronal activity was absent following re-feeding. These effects were not present in ghrelin-/- mice, suggesting that adult-born cells are uniquely sensitive to changes in ghrelin mediated by fasting and re-feeding. In summary, ghrelin does not promote neurogenesis in the SVZ and OB; however, new adult-born OB cells are activated by CR in a ghrelin-dependent manner.
Collapse
Affiliation(s)
- Michael Ratcliff
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Daniel Rees
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Scott McGrady
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Luke Buntwal
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Amanda K E Hornsby
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Jaqueline Bayliss
- Biomedical Discovery Unit, Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - Brianne A Kent
- Department of Medicine, University of British Columbia, Vancouver, British Columbia, Canada
| | | | | | - Amy L Beynon
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Owain W Howell
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Alwena H Morgan
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| | - Yuxiang Sun
- Department of Nutrition and Food Science, Texas A&M University, College Station, Texas, USA
| | - Zane B Andrews
- Biomedical Discovery Unit, Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - Timothy Wells
- School of Biosciences, Cardiff University, Cardiff, UK
| | - Jeffrey S Davies
- Molecular Neurobiology, Institute of Life Sciences, School of Medicine, Swansea University, Swansea, UK
| |
Collapse
|
28
|
Abizaid A. Stress and obesity: The ghrelin connection. J Neuroendocrinol 2019; 31:e12693. [PMID: 30714236 DOI: 10.1111/jne.12693] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/15/2018] [Revised: 01/01/2019] [Accepted: 01/29/2019] [Indexed: 12/20/2022]
Abstract
Ghrelin is a hormone associated with feeding and energy balance. Not surprisingly, this hormone is secreted in response to acute stressors and it is chronically elevated after exposure to chronic stress in tandem with a number of metabolic changes aimed at attaining homeostatic balance. In the present review, we propose that ghrelin plays a key role in these stress-induced homeostatic processes. Ghrelin targets the hypothalamus and brain stem nuclei that are part of the sympathetic nervous system to increase appetite and energy expenditure and promote the use of carbohydrates as a source of fuel at the same time as sparing fat. Ghrelin also targets mesolimbic brain regions such as the ventral segmental area and the hippocampus to modulate reward processes, to protect against damage associated with chronic stress, as well as to potentially increase resilience to stress. In all, these data support the notion that ghrelin, similar to corticosterone, is a critical metabolic hormone that is essential for the stress response.
Collapse
Affiliation(s)
- Alfonso Abizaid
- Department of Neuroscience, Carleton University, Ottawa, Ontario, Canada
| |
Collapse
|
29
|
Huang HJ, Chen XR, Han QQ, Wang J, Pilot A, Yu R, Liu Q, Li B, Wu GC, Wang YQ, Yu J. The protective effects of Ghrelin/GHSR on hippocampal neurogenesis in CUMS mice. Neuropharmacology 2019; 155:31-43. [PMID: 31103617 DOI: 10.1016/j.neuropharm.2019.05.013] [Citation(s) in RCA: 50] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/29/2018] [Revised: 04/27/2019] [Accepted: 05/12/2019] [Indexed: 12/18/2022]
Abstract
Ghrelin is an orexigenic hormone that also plays an important role in mood disorders. Our previous studies demonstrated that ghrelin administration could protect against depression-like behaviors of chronic unpredictable mild stress (CUMS) in rodents. However, the mechanism related to the effect of ghrelin on CUMS mice has yet to be revealed. This article shows that ghrelin (5 nmol/kg/day for 2 weeks, i.p.) decreased depression-like behaviors induced by CUMS and increased hippocampal integrity (neurogenesis and spine density) measured via Ki67, 5-bromo-2-deoxyuridine (BrdU), doublecortin (DCX) labeling and Golgi-cox staining, which were decreased under CUMS. The behavioral phenotypes of Growth hormone secretagogue receptor (Ghsr)-null and wild type (WT) mice were evaluated under no stress condition and after CUMS exposure to determine the effect of Ghsr knockout on the behavioral phenotypes and stress susceptibility of mice. Ghsr-null mice exhibited depression-like behaviors under no stress condition. CUMS induced similar depression- and anxiety-like behavioral manifestations in both Ghsr-null and WT mice. A similar pattern of behavioral changes was observed after hippocampal GHSR knockdown. Additionally, both Ghsr knockout as well as CUMS exhibited deleterious effects on neurogenesis and spine density in the dentate gyrus (DG). Besides, CCK8 assay and 5-Ethynyl-2'-deoxyuridine (EdU) incorporation assay showed that ghrelin has a proliferative effect on primary cultured hippocampal neural stem cells (NSCs) and this proliferation was blocked by D-Lys3-GHRP-6 (DLS, the antagonist of GHSR, 100 μM) pretreatment. Ghrelin-induced proliferation is associated with the inhibition of G1 arrest, and this inhibition was blocked by LY294002 (specific inhibitor of PI3K, 20 μM). Furthermore, the in vivo data displayed that LY294002 (50 nmol, i.c.v.) can significantly block the antidepressant-like action of exogenous ghrelin treatment. All these results suggest that ghrelin/GHSR signaling maintains the integrity of hippocampus and has an inherent neuroprotective effect whether facing stress or not.
Collapse
Affiliation(s)
- Hui-Jie Huang
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Xiao-Rong Chen
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Qiu-Qin Han
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China; Shanghai University of Medicine and Health Sciences, Shanghai, 201318, China
| | - Jing Wang
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Adam Pilot
- Sino-Danish College, University of Chinese Academy of Sciences, Beijing, 100049, China
| | - Rui Yu
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Qiong Liu
- Department of Anatomy, Histology and Embryology, School of Basic Medical Sciences, Shanghai Medical College, Fudan University, Shanghai, 200032, China; Key Laboratory of Medical Imaging Computing and Computer Assisted Intervention of Shanghai, Shanghai, 200032, China
| | - Bing Li
- Center Laboratories, Jinshan Hospital of Fudan University, Shanghai, 201508, China
| | - Gen-Cheng Wu
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Yan-Qing Wang
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China
| | - Jin Yu
- Department of Integrative Medicine and Neurobiology, State Key Laboratory of Medical Neurobiology, School of Basic Medical Sciences, Institutes of Brain Science, Brain Science Collaborative Innovation Center, Shanghai Medical College, Fudan University, Shanghai, 200032, China.
| |
Collapse
|
30
|
Ghrelin Promotes Cortical Neurites Growth in Late Stage After Oxygen-Glucose Deprivation/Reperfusion Injury. J Mol Neurosci 2019; 68:29-37. [PMID: 30806968 DOI: 10.1007/s12031-019-01279-y] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/11/2018] [Accepted: 02/11/2019] [Indexed: 01/19/2023]
Abstract
Acyl ghrelin, a novel brain-gut peptide, is an endogenous ligand for the growth hormone secretagogue receptor. Accumulated research data have shown that acyl ghrelin exercises a significant neuroprotective effect against cerebral ischemia/reperfusion (I/R) injury in animal models and in cultured neurons during the acute phase, usually, 1 day after cerebral ischemia. The chronic effects of acyl ghrelin 1 week after brain ischemia remain largely unknown. In this study, we explored the effects of acyl ghrelin on cultured organotypic brain slices and cortical neurons which were injured by oxygen-glucose deprivation/reperfusion(OGD/R) for 7 days. The underlying molecular mechanisms were deciphered based on label-free proteomic analysis. Acyl ghrelin treatment promoted neurite (axons and dendrites) growth and alleviated the neuronal damage in both cultured brain slices and neurons. Proteomic analysis showed that cell division control protein 42 (Cdc42) mediates the effects of acyl ghrelin on neurite growth. Acyl ghrelin stimulated the expression of Cdc42 and neurite growth in cultured neurons comparing with OGD/R group. Inhibition of Cdc42 attenuated the effects of acyl ghrelin. These results suggest that acyl ghrelin promotes neurite growth during the later stage after OGD/R injury via Cdc42. Our study suggests that acyl ghrelin may be promising to restore the neuronal structure in the late phase after stroke.
Collapse
|
31
|
Cao X, Zhu M, He Y, Chu W, Du Y, Du H. Increased Serum Acylated Ghrelin Levels in Patients with Mild Cognitive Impairment. J Alzheimers Dis 2019; 61:545-552. [PMID: 29226871 DOI: 10.3233/jad-170721] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/28/2022]
Abstract
Ghrelin is a stomach-derived circulating hormone. In addition to its function as an orexigenic stimulant, the role of ghrelin in the consolidation of learning and memory has been implicated in recent years. However, the status of circulating acylated ghrelin (AG, that is, the functional form of ghrelin) in the symptomatic predementia stage of Alzheimer's disease (AD) has rarely been investigated. In the current study, we examined the serum levels of acylated and total ghrelin in 22 patients with mild cognitive impairment (MCI) and 30 cognitively normal controls. We have found that patients with MCI had significantly increased serum AG levels, which were inversely associated with defected short- and long-term memory as well as language skills. Of note, the levels of total circulating ghrelin were similar between the two groups. Intriguingly, serum AG but not total ghrelin was associated with AD risk factors including the age, hypertension, and hyperlipidemia. Therefore, circulating AG may serve as a potential early systemic biomarker for AD-related cognitive impairments. Nevertheless, the simplest interpretation of the results is that the levels of circulating AG are associated with cognitive impairments in patients with MCI, thereby forming the groundwork for our future studies on the systemic mechanisms of AD pertaining to the ghrelin system.
Collapse
Affiliation(s)
- Xi Cao
- Department of Neurology, Alzheimer's Disease Center, Qianfoshan Hospital affiliated to Shandong University, Jinan, Shandong, PRC
| | - Min Zhu
- Department of Neurology, Alzheimer's Disease Center, Qianfoshan Hospital affiliated to Shandong University, Jinan, Shandong, PRC
| | - Yan He
- Department of Neurology, Alzheimer's Disease Center, Qianfoshan Hospital affiliated to Shandong University, Jinan, Shandong, PRC
| | - Wenzheng Chu
- Department of Neurology, Alzheimer's Disease Center, Qianfoshan Hospital affiliated to Shandong University, Jinan, Shandong, PRC
| | - Yifeng Du
- Department of Neurology, Shandong Provincial Hospital, Jinan, Shandong, PRC
| | - Heng Du
- Department of Neurology, Alzheimer's Disease Center, Qianfoshan Hospital affiliated to Shandong University, Jinan, Shandong, PRC.,Department of Biological Sciences, the University of Texas, Dallas, Richardson, TX, USA
| |
Collapse
|
32
|
Elabi OF, Duskova K, Davies JS, Lane EL. The Impact of Ghrelin on the Survival and Efficacy of Dopaminergic Fetal Grafts in the 6-OHDA-Lesioned Rat. Neuroscience 2018; 395:13-21. [PMID: 30414880 DOI: 10.1016/j.neuroscience.2018.10.045] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2018] [Revised: 10/31/2018] [Accepted: 10/31/2018] [Indexed: 12/21/2022]
Abstract
Ghrelin is a peptide produced in the gut with a wide range of physiological functions. Recent studies have suggested it may have potential as a neuroprotective agent in models of Parkinson's disease, reducing the impact of toxic challenges on the survival of nigral dopaminergic neurons. The presence of the ghrelin receptor (GHSR1a) on the dopaminergic neurons of the substantia nigra raises the possibility that a potential application for this property of ghrelin may be as an adjunctive neuroprotective agent to enhance and support the survival and integration of dopaminergic cells transplanted into the striatum. Thus far, inconsistent outcomes in clinical trials for fetal cell transplantation have been linked to low rates of cell survival which we hypothesize could be ameliorated by the presence of ghrelin. To explore this, we confirmed the expression of the GHSR1a and related enzymes on e14 ventral mesencephalon. To determine a functional effect, five groups of female Sprague-Dawley rats received a unilateral 6-OHDA lesion to the medial forebrain bundle and four received an intrastriatal graft of e14 ventral mesencephalic cells. Grafted rats received saline; acyl-ghrelin (10 µg/kg); acyl-ghrelin (50 µg/kg) or the ghrelin agonist JMV-2894 (160 µg/kg) i.p. for 8 weeks. An effect of ghrelin at low dose on hippocampal neurogenesis indicated blood-brain barrier penetrance and attainment of biologically relevant levels but neither acyl-ghrelin nor JMV-2894 improved graft survival or efficacy.
Collapse
Affiliation(s)
- O F Elabi
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, CF10 3NB, UK.
| | - K Duskova
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, CF10 3NB, UK
| | - J S Davies
- Insitute of Life Sciences, School of Medicine, Swansea University, SA2 8PP, UK
| | - E L Lane
- School of Pharmacy and Pharmaceutical Sciences, Cardiff University, CF10 3NB, UK.
| |
Collapse
|
33
|
Hueston CM, O'Leary JD, Hoban AE, Kozareva DA, Pawley LC, O'Leary OF, Cryan JF, Nolan YM. Chronic interleukin-1β in the dorsal hippocampus impairs behavioural pattern separation. Brain Behav Immun 2018; 74:252-264. [PMID: 30217534 DOI: 10.1016/j.bbi.2018.09.015] [Citation(s) in RCA: 32] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/21/2018] [Revised: 08/31/2018] [Accepted: 09/10/2018] [Indexed: 02/04/2023] Open
Abstract
Understanding the long-term consequences of chronic inflammation in the hippocampus may help to develop therapeutic targets for the treatment of cognitive disorders related to stress, ageing and neurodegeneration. The hippocampus is particularly vulnerable to increases in the pro-inflammatory cytokine interleukin-1β (IL-1β), a mediator of neuroinflammation, with elevated levels implicated in the aetiology of neurodegenerative diseases such as Alzheimer's and Parkinson's, and in stress-related disorders such as depression. Acute increases in hippocampal IL-1β have been shown to impair cognition and reduce adult hippocampal neurogenesis, the birth of new neurons. However, the impact of prolonged increases in IL-1β, as evident in clinical conditions, on cognition has not been fully explored. Therefore, the present study utilized a lentiviral approach to induce long-term overexpression of IL-1β in the dorsal hippocampus of adult male Sprague Dawley rats and examine its impact on cognition. Following three weeks of viral integration, pattern separation, a process involving hippocampal neurogenesis, was impaired in IL-1β-treated rats in both object-location and touchscreen operant paradigms. This was coupled with a decrease in the number and neurite complexity of immature neurons in the hippocampus. Conversely, tasks involving the hippocampus, but not sensitive to disruption of hippocampal neurogenesis, including spontaneous alternation, novel object and location recognition were unaffected. Touchscreen operant visual discrimination, a cognitive task involving the prefrontal cortex, was largely unaffected by IL-1β overexpression. In conclusion, these findings suggest that chronically elevated IL-1β in the hippocampus selectively impairs pattern separation. Inflammatory-mediated disruption of adult hippocampal neurogenesis may contribute to the cognitive decline associated with neurodegenerative and stress-related disorders.
Collapse
Affiliation(s)
- Cara M Hueston
- Department of Anatomy and Neuroscience, University College Cork, Ireland; APC Microbiome Ireland, University College Cork, Ireland
| | - James D O'Leary
- Department of Anatomy and Neuroscience, University College Cork, Ireland
| | - Alan E Hoban
- Department of Anatomy and Neuroscience, University College Cork, Ireland
| | - Danka A Kozareva
- Department of Anatomy and Neuroscience, University College Cork, Ireland
| | - Lauren C Pawley
- Department of Anatomy and Neuroscience, University College Cork, Ireland
| | - Olivia F O'Leary
- Department of Anatomy and Neuroscience, University College Cork, Ireland; APC Microbiome Ireland, University College Cork, Ireland
| | - John F Cryan
- Department of Anatomy and Neuroscience, University College Cork, Ireland; APC Microbiome Ireland, University College Cork, Ireland
| | - Yvonne M Nolan
- Department of Anatomy and Neuroscience, University College Cork, Ireland; APC Microbiome Ireland, University College Cork, Ireland.
| |
Collapse
|
34
|
Lockie SH, Stark R, Mequinion M, Ch’ng S, Kong D, Spanswick DC, Lawrence AJ, Andrews ZB. Glucose Availability Predicts the Feeding Response to Ghrelin in Male Mice, an Effect Dependent on AMPK in AgRP Neurons. Endocrinology 2018; 159:3605-3614. [PMID: 30204871 PMCID: PMC6169619 DOI: 10.1210/en.2018-00536] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/04/2018] [Accepted: 09/05/2018] [Indexed: 01/31/2023]
Abstract
Metabolic feedback from the periphery to the brain results from a dynamic physiologic fluctuation of nutrients and hormones, including glucose and fatty acids, ghrelin, leptin, and insulin. The specific interactions between humoral factors and how they influence feeding is largely unknown. We hypothesized that acute glucose availability may alter how the brain responds to ghrelin, a hormonal signal of energy availability. Acute glucose administration suppressed a range of ghrelin-induced behaviors as well as gene expression changes in hypothalamic neuropeptide Y (NPY) and agouti-related peptide (AgRP) neurons after ghrelin administration. Knockdown of the energy-sensing molecule AMP-activated protein kinase (AMPK) in AgRP neurons resulted in loss of the glucose effect, and mice responded as though pretreated with saline. Conversely, 2-deoxyglucose (2-DG), which decreases glucose availability, potentiated ghrelin-induced feeding and increased hypothalamic NPY mRNA levels. AMPK knockdown did not alter the additive effect of 2-DG and ghrelin on feeding. Our findings support the idea that computation of energy status is dynamic, is informed by multiple signals, and responds to acute fluctuations in metabolic state. These observations are broadly relevant to the investigation of neuroendocrine control of feeding and highlight the underappreciated complexity of control within these systems.
Collapse
Affiliation(s)
- Sarah H Lockie
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Romana Stark
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Mathieu Mequinion
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Sarah Ch’ng
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Dong Kong
- Department of Neuroscience, Tufts University School of Medicine, Boston, Massachusetts
- Program in Neuroscience, Sackler School of Graduate Biomedical Sciences, Boston, Massachusetts
| | - David C Spanswick
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| | - Andrew J Lawrence
- The Florey Institute of Neuroscience and Mental Health, The University of Melbourne, Parkville, Victoria, Australia
| | - Zane B Andrews
- Monash Biomedicine Discovery Institute, Monash University, Clayton, Victoria, Australia
- Department of Physiology, Monash University, Clayton, Victoria, Australia
| |
Collapse
|
35
|
Martínez Damonte V, Rodríguez SS, Raingo J. Growth hormone secretagogue receptor constitutive activity impairs voltage-gated calcium channel-dependent inhibitory neurotransmission in hippocampal neurons. J Physiol 2018; 596:5415-5428. [PMID: 30199095 DOI: 10.1113/jp276256] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2018] [Accepted: 09/06/2018] [Indexed: 12/14/2022] Open
Abstract
KEY POINTS Presynaptic CaV 2 voltage-gated calcium channels link action potentials arriving at the presynaptic terminal to neurotransmitter release. Hence, their regulation is essential to fine tune brain circuitry. CaV 2 channels are highly sensitive to G protein-coupled receptor (GPCR) modulation. Our previous data indicated that growth hormone secretagogue receptor (GHSR) constitutive activity impairs CaV 2 channels by decreasing their surface density. We present compelling support for the impact of CaV 2.2 channel inhibition by agonist-independent GHSR activity exclusively on GABA release in hippocampal cultures. We found that this selectivity arises from a high reliance of GABA release on CaV 2.2 rather than on CaV 2.1 channels. Our data provide new information on the effects of the ghrelin-GHSR system on synaptic transmission, suggesting a putative physiological role of the constitutive signalling of a GPCR that is expressed at high levels in brain areas with restricted access to its natural agonist. ABSTRACT Growth hormone secretagogue receptor (GHSR) displays high constitutive activity, independent of its endogenous ligand, ghrelin. Unlike ghrelin-induced GHSR activity, the physiological role of GHSR constitutive activity and the mechanisms that underlie GHSR neuronal modulation remain elusive. We previously demonstrated that GHSR constitutive activity modulates presynaptic CaV 2 voltage-gated calcium channels. Here we postulate that GHSR constitutive activity-mediated modulation of CaV 2 channels could be relevant in the hippocampus since this brain area has high GHSR expression but restricted access to ghrelin. We performed whole-cell patch-clamp in hippocampal primary cultures from E16- to E18-day-old C57BL6 wild-type and GHSR-deficient mice after manipulating GHSR expression with lentiviral transduction. We found that GHSR constitutive activity impairs CaV 2.1 and CaV 2.2 native calcium currents and that CaV 2.2 basal impairment leads to a decrease in GABA but not glutamate release. We postulated that this selective effect is related to a higher CaV 2.2 over CaV 2.1 contribution to GABA release (∼40% for CaV 2.2 in wild-type vs. ∼20% in wild-type GHSR-overexpressing cultures). This effect of GHSR constitutive activity is conserved in hippocampal brain slices, where GHSR constitutive activity reduces local GABAergic transmission of the granule cell layer (intra-granule cell inhibitory postsynaptic current (IPSC) size ∼-67 pA in wild-type vs. ∼-100 pA in GHSR-deficient mice), whereas the glutamatergic output from the dentate gyrus to CA3 remains unchanged. In summary, we found that GHSR constitutive activity impairs IPSCs both in hippocampal primary cultures and in brain slices through a CaV 2-dependent mechanism without affecting glutamatergic transmission.
Collapse
Affiliation(s)
- Valentina Martínez Damonte
- Multidisciplinary Institute of Cell Biology (IMBICE), National Council of Science and Technology (CONICET), Buenos Aires Comision of Science (CIC) and La Plata University (UNLP), La Plata, Argentina
| | - Silvia Susana Rodríguez
- Multidisciplinary Institute of Cell Biology (IMBICE), National Council of Science and Technology (CONICET), Buenos Aires Comision of Science (CIC) and La Plata University (UNLP), La Plata, Argentina
| | - Jesica Raingo
- Multidisciplinary Institute of Cell Biology (IMBICE), National Council of Science and Technology (CONICET), Buenos Aires Comision of Science (CIC) and La Plata University (UNLP), La Plata, Argentina
| |
Collapse
|
36
|
Seminara RS, Jeet C, Biswas S, Kanwal B, Iftikhar W, Sakibuzzaman M, Rutkofsky IH. The Neurocognitive Effects of Ghrelin-induced Signaling on the Hippocampus: A Promising Approach to Alzheimer's Disease. Cureus 2018; 10:e3285. [PMID: 30443455 PMCID: PMC6235652 DOI: 10.7759/cureus.3285] [Citation(s) in RCA: 13] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2018] [Accepted: 09/11/2018] [Indexed: 12/17/2022] Open
Abstract
The communication between the gastrointestinal tract and the central nervous system (CNS) allows for certain peptide hormones to influence neurocognitive function. Ghrelin, also known as the 'hunger hormone,' has the unique ability to enter the CNS and interact with the growth hormone secretagogue receptor (GHS-R) within the hippocampus. Upon interaction with ghrelin, a conformational change in the receptor causes an increase in transcription factors to foster a wide array of physiologic changes in response to caloric deprivation. With the GHS-R in a relatively high concentration within the hippocampus, ghrelin can promote memory, spatial, learning, and behavioral effects. In fact, ghrelin appears to also have a neuroprotective and neuromodulatory response once active within the hippocampal dentate gyrus. Through the GHS-R, higher levels of ghrelin may alter cognitive circuitry and offer a possible link to the treatment of some pathologies implicated in neurological dysfunction. Alzheimer's disease (AD) is already becoming a significant target for ghrelin neuroreceptor therapy. In such experimental models, ghrelin has been shown to combat this degenerative process by eliciting an ameliorative and regenerative response. Although trials and research are still ongoing, further studies are indicated as early research into this adjuvant therapy is promising. The research team explored the effects of ghrelin by reviewing the downstream signaling modifications of ghrelin's interaction with a specific CNS receptor, the GHS-R. Although the GHS-R is found in multiple locations within the CNS, the team investigated the role of the GHS-R within the hippocampus to focus solely on the neurocognitive implications of ghrelin. The team noted which signaling pathways in particular that ghrelin initiated and used this approach to determine whether ghrelin may have any therapeutic benefits. The team explored the possible therapeutic indications of ghrelin by looking at studies conducted with a specific neurodegenerative disease known to target the hippocampus.
Collapse
Affiliation(s)
- Robert S Seminara
- Neuroscience, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Charan Jeet
- Research, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Sharmi Biswas
- Pediatrics, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Bushra Kanwal
- Department of Research, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Waleed Iftikhar
- Internal Medicine, CMH Lahore Medical College and Institute of Dentistry, Lahore, PAK
| | - Md Sakibuzzaman
- Neuroscience, California Institute of Behavioral Neurosciences & Psychology, Fairfield, USA
| | - Ian H Rutkofsky
- Medicine, International American University College of Medicine, Washington, D.C., USA
| |
Collapse
|
37
|
Dietary influences on cognition. Physiol Behav 2018; 192:118-126. [PMID: 29501837 DOI: 10.1016/j.physbeh.2018.02.052] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2017] [Revised: 02/27/2018] [Accepted: 02/28/2018] [Indexed: 01/01/2023]
Abstract
Obesity is a world-wide crisis with profound healthcare and socio-economic implications and it is now clear that the central nervous system (CNS) is a target for the complications of metabolic disorders like obesity. In addition to decreases in physical activity and sedentary lifestyles, diet is proposed to be an important contributor to the etiology and progression of obesity. Unfortunately, there are gaps in our knowledge base related to how dietary choices impact the structural and functional integrity of the CNS. For example, while chronic consumption of hypercaloric diets (increased sugars and fat) contribute to increases in body weight and adiposity characteristic of metabolic disorders, the mechanistic basis for neurocognitive deficits in obesity remains to be determined. In addition, studies indicate that acute consumption of hypercaloric diets impairs performance in a wide variety of cognitive domains, even in normal non-obese control subjects. These results from the clinical and basic science literature indicate that diet can have rapid, as well as long lasting effects on cognitive function. This review summarizes our symposium at the 2017 Society for the Study of Ingestive Behavior (SSIB) meeting that discussed these effects of diet on cognition. Collectively, this review highlights the need for integrated and comprehensive approaches to more fully determine how diet impacts behavior and cognition under physiological conditions and in metabolic disorders like type 2 diabetes mellitus (T2DM) and obesity.
Collapse
|
38
|
Morgan AH, Rees DJ, Andrews ZB, Davies JS. Ghrelin mediated neuroprotection - A possible therapy for Parkinson's disease? Neuropharmacology 2017; 136:317-326. [PMID: 29277488 DOI: 10.1016/j.neuropharm.2017.12.027] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2017] [Revised: 12/15/2017] [Accepted: 12/17/2017] [Indexed: 12/31/2022]
Abstract
Parkinson's disease is a common age-related neurodegenerative disorder affecting 10 million people worldwide, but the mechanisms underlying its pathogenesis are still unclear. The disease is characterised by dopamine nerve cell loss in the mid-brain and intra-cellular accumulation of α-synuclein that results in motor and non-motor dysfunction. In this review, we discuss the neuroprotective effects of the stomach hormone, ghrelin, in models of Parkinson's disease. Recent findings suggest that it may modulate mitochondrial function and autophagic clearance of impaired organelle in response to changes in cellular energy balance. We consider the putative cellular mechanisms underlying ghrelin-action and the possible role of ghrelin mimetics in slowing or preventing Parkinson's disease progression. This article is part of the Special Issue entitled 'Metabolic Impairment as Risk Factors for Neurodegenerative Disorders.'
Collapse
Affiliation(s)
- Alwena H Morgan
- Molecular Neurobiology, Institute of Life Science, Medical School, Swansea University, UK
| | - Daniel J Rees
- Molecular Neurobiology, Institute of Life Science, Medical School, Swansea University, UK
| | - Zane B Andrews
- Biomedicine Discovery Institute & Department of Physiology, Monash University, Melbourne, Victoria, Australia
| | - Jeffrey S Davies
- Molecular Neurobiology, Institute of Life Science, Medical School, Swansea University, UK.
| |
Collapse
|
39
|
Poulose SM, Miller MG, Scott T, Shukitt-Hale B. Nutritional Factors Affecting Adult Neurogenesis and Cognitive Function. Adv Nutr 2017; 8:804-811. [PMID: 29141966 PMCID: PMC5683005 DOI: 10.3945/an.117.016261] [Citation(s) in RCA: 134] [Impact Index Per Article: 19.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022] Open
Abstract
Adult neurogenesis, a complex process by which stem cells in the hippocampal brain region differentiate and proliferate into new neurons and other resident brain cells, is known to be affected by many intrinsic and extrinsic factors, including diet. Neurogenesis plays a critical role in neural plasticity, brain homeostasis, and maintenance in the central nervous system and is a crucial factor in preserving the cognitive function and repair of damaged brain cells affected by aging and brain disorders. Intrinsic factors such as aging, neuroinflammation, oxidative stress, and brain injury, as well as lifestyle factors such as high-fat and high-sugar diets and alcohol and opioid addiction, negatively affect adult neurogenesis. Conversely, many dietary components such as curcumin, resveratrol, blueberry polyphenols, sulforaphane, salvionic acid, polyunsaturated fatty acids (PUFAs), and diets enriched with polyphenols and PUFAs, as well as caloric restriction, physical exercise, and learning, have been shown to induce neurogenesis in adult brains. Although many of the underlying mechanisms by which nutrients and dietary factors affect adult neurogenesis have yet to be determined, nutritional approaches provide promising prospects to stimulate adult neurogenesis and combat neurodegenerative diseases and cognitive decline. In this review, we summarize the evidence supporting the role of nutritional factors in modifying adult neurogenesis and their potential to preserve cognitive function during aging.
Collapse
Affiliation(s)
- Shibu M Poulose
- USDA-ARS Human Nutrition Research Center on Aging at Tufts University, Neuroscience and Aging Laboratory, Boston, MA
| | - Marshall G Miller
- USDA-ARS Human Nutrition Research Center on Aging at Tufts University, Neuroscience and Aging Laboratory, Boston, MA
| | - Tammy Scott
- USDA-ARS Human Nutrition Research Center on Aging at Tufts University, Neuroscience and Aging Laboratory, Boston, MA
| | - Barbara Shukitt-Hale
- USDA-ARS Human Nutrition Research Center on Aging at Tufts University, Neuroscience and Aging Laboratory, Boston, MA
| |
Collapse
|
40
|
Morgan AH, Andrews ZB, Davies JS. Less is more: Caloric regulation of neurogenesis and adult brain function. J Neuroendocrinol 2017; 29. [PMID: 28771924 DOI: 10.1111/jne.12512] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/14/2017] [Revised: 07/20/2017] [Accepted: 07/26/2017] [Indexed: 12/11/2022]
Abstract
Calorie intake is essential for regulating normal physiological processes and is fundamental to maintaining life. Indeed, both extremes of calorie intake result in increased morbidity and mortality. In this review, we discuss the effect of calorie intake on adult brain function, with an emphasis on the beneficial effects of mild calorie restriction. Recent findings relating to the regenerative and protective effects of the gastrointestinal hormone, ghrelin, suggest that it may underlie the beneficial effects of calorie restriction. We discuss the putative cellular mechanisms underlying the action of ghrelin and their possible role in supporting healthy brain ageing.
Collapse
Affiliation(s)
- A H Morgan
- Molecular Neurobiology, Institute of Life Science, School of Medicine, Swansea University, Swansea, UK
| | - Z B Andrews
- Department of Physiology, Biomedicine Discovery Institute, Monash University, Melbourne, VIC, Australia
| | - J S Davies
- Molecular Neurobiology, Institute of Life Science, School of Medicine, Swansea University, Swansea, UK
| |
Collapse
|
41
|
Ge T, Yang W, Fan J, Li B. Preclinical evidence of ghrelin as a therapeutic target in epilepsy. Oncotarget 2017; 8:59929-59939. [PMID: 28938694 PMCID: PMC5601790 DOI: 10.18632/oncotarget.18349] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2017] [Accepted: 05/22/2017] [Indexed: 12/17/2022] Open
Abstract
Ghrelin, an orexigenic peptide synthesized by endocrine cells of the gastric mucosa, plays a major role in inhibiting seizures. However, the underlying mechanism of ghrelin's anticonvulsant action is still unclear. Nowadays, there are considerable evidences showing that ghrelin is implicated in various neurophysiological processes, including learning and memory, neuroprotection, neurogenesis, and inflammatory effects. In this review, we will summarize the effects of ghrelin on epilepsy. It may provide a comprehensive picture of the role of ghrelin in epilepsy.
Collapse
Affiliation(s)
- Tongtong Ge
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetics, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - Wei Yang
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetics, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - Jie Fan
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetics, The Second Hospital of Jilin University, Changchun 130041, PR China
| | - Bingjin Li
- Jilin Provincial Key Laboratory on Molecular and Chemical Genetics, The Second Hospital of Jilin University, Changchun 130041, PR China
| |
Collapse
|
42
|
Anacker C, Hen R. Adult hippocampal neurogenesis and cognitive flexibility - linking memory and mood. Nat Rev Neurosci 2017; 18:335-346. [PMID: 28469276 DOI: 10.1038/nrn.2017.45] [Citation(s) in RCA: 615] [Impact Index Per Article: 87.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
Abstract
Adult hippocampal neurogenesis has been implicated in cognitive processes, such as pattern separation, and in the behavioural effects of stress and antidepressants. Young adult-born neurons have been shown to inhibit the overall activity of the dentate gyrus by recruiting local interneurons, which may result in sparse contextual representations and improved pattern separation. We propose that neurogenesis-mediated inhibition also reduces memory interference and enables reversal learning both in neutral situations and in emotionally charged ones. Such improved cognitive flexibility may in turn help to decrease anxiety-like and depressive-like behaviour.
Collapse
Affiliation(s)
- Christoph Anacker
- Department of Psychiatry, Columbia University and Research Foundation for Mental Hygiene, New York State Psychiatric Institute, 1051 Riverside Drive, New York 10032, New York, USA
| | - René Hen
- Department of Psychiatry, Columbia University and Research Foundation for Mental Hygiene, New York State Psychiatric Institute, 1051 Riverside Drive, New York 10032, New York, USA.,Department of Neuroscience, Columbia University, Kolb Annex, 40 Haven Ave, New York 10032, New York, USA.,Department of Pharmacology, Columbia University, 630 West 168th Street, New York 10032, New York, USA
| |
Collapse
|
43
|
Santos VV, Stark R, Rial D, Silva HB, Bayliss JA, Lemus MB, Davies JS, Cunha RA, Prediger RD, Andrews ZB. Acyl ghrelin improves cognition, synaptic plasticity deficits and neuroinflammation following amyloid β (Aβ1-40) administration in mice. J Neuroendocrinol 2017; 29. [PMID: 28380673 DOI: 10.1111/jne.12476] [Citation(s) in RCA: 44] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/27/2016] [Revised: 03/16/2017] [Accepted: 04/03/2017] [Indexed: 12/24/2022]
Abstract
Ghrelin is a metabolic hormone that has neuroprotective actions in a number of neurological conditions, including Parkinson's disease (PD), stroke and traumatic brain injury. Acyl ghrelin treatment in vivo and in vitro also shows protective capacity in Alzheimer's disease (AD). In the present study, we used ghrelin knockout (KO) and their wild-type littermates to test whether or not endogenous ghrelin is protective in a mouse model of AD, in which human amyloid β peptide 1-40 (Aβ1-40 ) was injected into the lateral ventricles i.c.v. Recognition memory, using the novel object recognition task, was significantly impaired in ghrelin KO mice and after i.c.v. Aβ1-40 treatment. These deficits could be prevented by acyl ghrelin injections for 7 days. Spatial orientation, as assessed by the Y-maze task, was also significantly impaired in ghrelin KO mice and after i.c.v. Aβ1-40 treatment. These deficits could be prevented by acyl ghrelin injections for 7 days. Ghrelin KO mice had deficits in olfactory discrimination; however, neither i.c.v. Aβ1-40 treatment, nor acyl ghrelin injections affected olfactory discrimination. We used stereology to show that ghrelin KO and Aβ1-40 increased the total number of glial fibrillary acidic protein expressing astrocytes and ionised calcium-binding adapter expressing microglial in the rostral hippocampus. Finally, Aβ1-40 blocked long-term potentiation induced by high-frequency stimulation and this effect could be acutely blocked with co-administration of acyl ghrelin. Collectively, our studies demonstrate that ghrelin deletion affects memory performance and also that acyl ghrelin treatment may delay the onset of early events of AD. This supports the idea that acyl ghrelin treatment may be therapeutically beneficial with respect to restricting disease progression in AD.
Collapse
Affiliation(s)
- V V Santos
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, VIC, Australia
| | - R Stark
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, VIC, Australia
| | - D Rial
- Department of Pharmacology, Center of Biological Sciences, Universidade Federal de Santa Catarina UFSC, Florianópolis, SC, Brazil
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - H B Silva
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
| | - J A Bayliss
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, VIC, Australia
| | - M B Lemus
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, VIC, Australia
| | - J S Davies
- Molecular Neurobiology, Institute of Life Science, Swansea University, Swansea, UK
| | - R A Cunha
- CNC - Center for Neuroscience and Cell Biology, University of Coimbra, Coimbra, Portugal
- Faculty of Medicine, University of Coimbra, Coimbra, Portugal
| | - R D Prediger
- Department of Pharmacology, Center of Biological Sciences, Universidade Federal de Santa Catarina UFSC, Florianópolis, SC, Brazil
| | - Z B Andrews
- Monash Biomedicine Discovery Institute and Department of Physiology, Monash University, Clayton, VIC, Australia
| |
Collapse
|
44
|
Colldén G, Tschöp MH, Müller TD. Therapeutic Potential of Targeting the Ghrelin Pathway. Int J Mol Sci 2017; 18:ijms18040798. [PMID: 28398233 PMCID: PMC5412382 DOI: 10.3390/ijms18040798] [Citation(s) in RCA: 101] [Impact Index Per Article: 14.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2017] [Revised: 04/03/2017] [Accepted: 04/06/2017] [Indexed: 02/07/2023] Open
Abstract
Ghrelin was discovered in 1999 as the endogenous ligand of the growth-hormone secretagogue receptor 1a (GHSR1a). Since then, ghrelin has been found to exert a plethora of physiological effects that go far beyond its initial characterization as a growth hormone (GH) secretagogue. Among the numerous well-established effects of ghrelin are the stimulation of appetite and lipid accumulation, the modulation of immunity and inflammation, the stimulation of gastric motility, the improvement of cardiac performance, the modulation of stress, anxiety, taste sensation and reward-seeking behavior, as well as the regulation of glucose metabolism and thermogenesis. Due to a variety of beneficial effects on systems’ metabolism, pharmacological targeting of the endogenous ghrelin system is widely considered a valuable approach to treat metabolic complications, such as chronic inflammation, gastroparesis or cancer-associated anorexia and cachexia. The aim of this review is to discuss and highlight the broad pharmacological potential of ghrelin pathway modulation for the treatment of anorexia, cachexia, sarcopenia, cardiopathy, neurodegenerative disorders, renal and pulmonary disease, gastrointestinal (GI) disorders, inflammatory disorders and metabolic syndrome.
Collapse
Affiliation(s)
- Gustav Colldén
- Institute for Diabetes and Obesity & Helmholtz Diabetes Center, Helmholtz Zentrum München German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany.
| | - Matthias H Tschöp
- Institute for Diabetes and Obesity & Helmholtz Diabetes Center, Helmholtz Zentrum München German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany.
- Division of Metabolic Diseases, Department of Medicine, Technische Universität München, 80333 Munich, Germany.
| | - Timo D Müller
- Institute for Diabetes and Obesity & Helmholtz Diabetes Center, Helmholtz Zentrum München German Research Center for Environmental Health (GmbH), 85764 Neuherberg, Germany.
- Institute for Diabetes and Obesity (IDO), Business Campus Garching-Hochbrück, Parkring 13, 85748 Garching, Germany.
| |
Collapse
|
45
|
Kent BA, Mistlberger RE. Sleep and hippocampal neurogenesis: Implications for Alzheimer's disease. Front Neuroendocrinol 2017; 45:35-52. [PMID: 28249715 DOI: 10.1016/j.yfrne.2017.02.004] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2016] [Revised: 01/23/2017] [Accepted: 02/24/2017] [Indexed: 01/29/2023]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia and currently there are no effective disease-modifying treatments available. Hallmark symptoms of AD include impaired hippocampus-dependent episodic memory and disrupted sleep and circadian rhythms. The pathways connecting these symptoms are of particular interest because it is well established that sleep and circadian disruption can impair hippocampus-dependent learning and memory. In rodents, these procedures also markedly suppress adult hippocampal neurogenesis, a form of brain plasticity that is believed to play an important role in pattern separation, and thus episodic memory. A causal role for sleep disruptions in AD pathophysiology is suggested by evidence for sleep-dependent glymphatic clearance of metabolic waste products from the brain. This review explores a complementary hypothesis that sleep and circadian disruptions in AD contribute to cognitive decline by activating neuroendocrine and neuroinflammatory signaling pathways that suppress hippocampal neurogenesis. Evidence for this hypothesis underscores the promise of sleep, circadian rhythms, and neurogenesis as therapeutic targets for remediation of memory impairment in AD.
Collapse
Affiliation(s)
- Brianne A Kent
- Division of Neurology and Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, Canada
| | | |
Collapse
|
46
|
Kim C, Kim S, Park S. Neurogenic Effects of Ghrelin on the Hippocampus. Int J Mol Sci 2017; 18:ijms18030588. [PMID: 28282857 PMCID: PMC5372604 DOI: 10.3390/ijms18030588] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2017] [Revised: 02/24/2017] [Accepted: 03/03/2017] [Indexed: 01/25/2023] Open
Abstract
Mammalian neurogenesis continues throughout adulthood in the subventricular zone of the lateral ventricle and in the subgranular zone of the dentate gyrus in the hippocampus. It is well known that hippocampal neurogenesis is essential in mediating hippocampus-dependent learning and memory. Ghrelin, a peptide hormone mainly synthesized in the stomach, has been shown to play a major role in the regulation of energy metabolism. A plethora of evidence indicates that ghrelin can also exert important effects on neurogenesis in the hippocampus of the adult brain. The aim of this review is to discuss the current role of ghrelin on the in vivo and in vitro regulation of neurogenesis in the adult hippocampus. We will also discuss the possible role of ghrelin in dietary restriction-induced hippocampal neurogenesis and the link between ghrelin-induced hippocampal neurogenesis and cognitive functions.
Collapse
Affiliation(s)
- Chanyang Kim
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Korea.
| | - Sehee Kim
- Department of Biomedical Science, Graduate School, Kyung Hee University, Seoul 02447, Korea.
| | - Seungjoon Park
- Department of Pharmacology and Medical Research Center for Bioreaction to Reactive Oxygen Species and Biomedical Science Institute, School of Medicine, Kyung Hee University, Seoul 02447, Korea.
| |
Collapse
|
47
|
Churm R, Davies JS, Stephens JW, Prior SL. Ghrelin function in human obesity and type 2 diabetes: a concise review. Obes Rev 2017; 18:140-148. [PMID: 27899023 DOI: 10.1111/obr.12474] [Citation(s) in RCA: 30] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/28/2016] [Revised: 09/06/2016] [Accepted: 09/06/2016] [Indexed: 12/12/2022]
Abstract
The 28 amino acid hormone, ghrelin, has been found to have various effects on metabolism. This review will focus on the pathways integrated into ghrelin's effect within the hypothalamus, pancreas and adipocytes. The identification of molecules and pathways that regulate ghrelin-mediated lipid retention could establish new mechanisms underlying cellular energy homeostasis. The impact of acyl-ghrelin on glucose metabolism and lipid homeostasis may allow for novel preventative or early intervention therapeutic strategies to treat obesity related type 2 diabetes and associated metabolic dysfunction.
Collapse
Affiliation(s)
- R Churm
- Diabetes Research Group, Institute of Life Science 1, Swansea University, Swansea, UK
| | - J S Davies
- Molecular Neurobiology Research Group, Institute of Life Science 1, Swansea University, Swansea, UK
| | - J W Stephens
- Diabetes Research Group, Institute of Life Science 1, Swansea University, Swansea, UK
| | - S L Prior
- Diabetes Research Group, Institute of Life Science 1, Swansea University, Swansea, UK
| |
Collapse
|
48
|
Kunath N, Müller NCJ, Tonon M, Konrad BN, Pawlowski M, Kopczak A, Elbau I, Uhr M, Kühn S, Repantis D, Ohla K, Müller TD, Fernández G, Tschöp M, Czisch M, Steiger A, Dresler M. Ghrelin modulates encoding-related brain function without enhancing memory formation in humans. Neuroimage 2016; 142:465-473. [PMID: 27402596 DOI: 10.1016/j.neuroimage.2016.07.016] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2016] [Revised: 06/07/2016] [Accepted: 07/06/2016] [Indexed: 01/24/2023] Open
Abstract
Ghrelin regulates energy homeostasis in various species and enhances memory in rodent models. In humans, the role of ghrelin in cognitive processes has yet to be characterized. Here we show in a double-blind randomized crossover design that acute administration of ghrelin alters encoding-related brain activity, however does not enhance memory formation in humans. Twenty-one healthy young male participants had to memorize food- and non-food-related words presented on a background of a virtual navigational route while undergoing fMRI recordings. After acute ghrelin administration, we observed decreased post-encoding resting state fMRI connectivity between the caudate nucleus and the insula, amygdala, and orbitofrontal cortex. In addition, brain activity related to subsequent memory performance was modulated by ghrelin. On the next day, however, no differences were found in free word recall or cued location-word association recall between conditions; and ghrelin's effects on brain activity or functional connectivity were unrelated to memory performance. Further, ghrelin had no effect on a cognitive test battery comprising tests for working memory, fluid reasoning, creativity, mental speed, and attention. In conclusion, in contrast to studies with animal models, we did not find any evidence for the potential of ghrelin acting as a short-term cognitive enhancer in humans.
Collapse
Affiliation(s)
- N Kunath
- Max Planck Institute of Psychiatry, Munich, Germany
| | - N C J Müller
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - M Tonon
- Max Planck Institute of Psychiatry, Munich, Germany
| | - B N Konrad
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - M Pawlowski
- Max Planck Institute of Psychiatry, Munich, Germany
| | - A Kopczak
- Max Planck Institute of Psychiatry, Munich, Germany
| | - I Elbau
- Max Planck Institute of Psychiatry, Munich, Germany
| | - M Uhr
- Max Planck Institute of Psychiatry, Munich, Germany
| | - S Kühn
- Max Planck Institute for Human Development, Berlin, Germany
| | - D Repantis
- Charité - Universitätsmedizin Berlin, Department of Psychiatry and Psychotherapy, CBF, Berlin, Germany
| | - K Ohla
- German Institute for Human Nutrition, Potsdam-Rehbrücke, Germany
| | - T D Müller
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, Munich, Germany; Department of Medicine, Technische Universität München, Munich, Germany
| | - G Fernández
- Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands
| | - M Tschöp
- Institute for Diabetes and Obesity, Helmholtz Zentrum München, Munich, Germany; Department of Medicine, Technische Universität München, Munich, Germany
| | - M Czisch
- Max Planck Institute of Psychiatry, Munich, Germany
| | - A Steiger
- Max Planck Institute of Psychiatry, Munich, Germany
| | - M Dresler
- Max Planck Institute of Psychiatry, Munich, Germany; Donders Institute for Brain, Cognition and Behaviour, Radboud University Medical Centre, Nijmegen, The Netherlands.
| |
Collapse
|
49
|
Liberini CG, Borner T, Boyle CN, Lutz TA. The satiating hormone amylin enhances neurogenesis in the area postrema of adult rats. Mol Metab 2016; 5:834-843. [PMID: 27688997 PMCID: PMC5034493 DOI: 10.1016/j.molmet.2016.06.015] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/09/2016] [Revised: 06/22/2016] [Accepted: 06/27/2016] [Indexed: 01/03/2023] Open
Abstract
OBJECTIVE Adult neurogenesis in the subgranular zone and subventricular zone is generally accepted, but its existence in other brain areas is still controversial. Circumventricular organs, such as the area postrema (AP) have recently been described as potential neurogenic niches in the adult brain. The AP is the major site of action of the satiating hormone amylin. Amylin has been shown to promote the formation of neuronal projections originating from the AP in neonatal rodents but the role of amylin in adult neurogenesis remains unknown. METHODS To test this, we first performed an RNA-sequencing of the AP of adult rats acutely injected with either amylin (20 μg/kg), amylin plus the amylin receptor antagonist AC187 (500 μg/kg) or vehicle. Second, animals were subcutaneously equipped with minipumps releasing either amylin (50 μg/kg/day) or vehicle for 3 weeks to assess cell proliferation and differentiation with the 5'-bromo-2-deoxyuridine (BrdU) technique. RESULTS Acute amylin injections affected genes involved in pathways and processes that control adult neurogenesis. Amylin consistently upregulated NeuroD1 transcript and protein in the adult AP, and this effect was blocked by the co-administration of AC187. Further, chronic amylin treatment increased the number of newly proliferated AP-cells and significantly promoted their differentiation into neurons rather than astrocytes. CONCLUSION Our findings revealed a novel role of the satiating hormone amylin in promoting neurogenesis in the AP of adult rats.
Collapse
Key Words
- AP, area postrema
- Adult neurogenesis
- Amylin
- Area postrema
- BrdU
- BrdU, 5′-bromo-2-deoxyuridine
- CR, calretinin
- CTR, calcitonin receptor
- CVO, circumventricular organs
- Circumventricular organs
- ERK1/2, extracellular signal-regulated kinase 1 and 2
- EphRs, ephrin receptors
- FDR, false discovery rate
- GO, gene ontology
- ME, median eminence
- NGS, next generation sequencing
- NSC, neural stem cells
- NeuroD, neuronal differentiation
- NeuroD1, neuronal differentiation-1
- RAMP, receptor activity-modifying protein
- Wnt, Wingless-Type MMTV Integration Site Family
- bHLH, basic helix-loop-helix
Collapse
Affiliation(s)
- Claudia G Liberini
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich (UZH), 8057 Zurich, Switzerland; Zurich Centre for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland; Zurich Centre for Clinical Studies, Vetsuisse Faculty University of Zurich, 8057 Zurich, Switzerland
| | - Tito Borner
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich (UZH), 8057 Zurich, Switzerland; Zurich Centre for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
| | - Christina N Boyle
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich (UZH), 8057 Zurich, Switzerland.
| | - Thomas A Lutz
- Institute of Veterinary Physiology, Vetsuisse Faculty University of Zurich (UZH), 8057 Zurich, Switzerland; Zurich Centre for Integrative Human Physiology (ZIHP), University of Zurich, 8057 Zurich, Switzerland
| |
Collapse
|
50
|
Adult neurogenesis and pattern separation in rodents: A critical evaluation of data, tasks and interpretation. ACTA ACUST UNITED AC 2016. [DOI: 10.1007/s11515-016-1406-2] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
|