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Loh JS, Mak WQ, Tan LKS, Ng CX, Chan HH, Yeow SH, Foo JB, Ong YS, How CW, Khaw KY. Microbiota-gut-brain axis and its therapeutic applications in neurodegenerative diseases. Signal Transduct Target Ther 2024; 9:37. [PMID: 38360862 PMCID: PMC10869798 DOI: 10.1038/s41392-024-01743-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 01/02/2024] [Accepted: 01/14/2024] [Indexed: 02/17/2024] Open
Abstract
The human gastrointestinal tract is populated with a diverse microbial community. The vast genetic and metabolic potential of the gut microbiome underpins its ubiquity in nearly every aspect of human biology, including health maintenance, development, aging, and disease. The advent of new sequencing technologies and culture-independent methods has allowed researchers to move beyond correlative studies toward mechanistic explorations to shed light on microbiome-host interactions. Evidence has unveiled the bidirectional communication between the gut microbiome and the central nervous system, referred to as the "microbiota-gut-brain axis". The microbiota-gut-brain axis represents an important regulator of glial functions, making it an actionable target to ameliorate the development and progression of neurodegenerative diseases. In this review, we discuss the mechanisms of the microbiota-gut-brain axis in neurodegenerative diseases. As the gut microbiome provides essential cues to microglia, astrocytes, and oligodendrocytes, we examine the communications between gut microbiota and these glial cells during healthy states and neurodegenerative diseases. Subsequently, we discuss the mechanisms of the microbiota-gut-brain axis in neurodegenerative diseases using a metabolite-centric approach, while also examining the role of gut microbiota-related neurotransmitters and gut hormones. Next, we examine the potential of targeting the intestinal barrier, blood-brain barrier, meninges, and peripheral immune system to counteract glial dysfunction in neurodegeneration. Finally, we conclude by assessing the pre-clinical and clinical evidence of probiotics, prebiotics, and fecal microbiota transplantation in neurodegenerative diseases. A thorough comprehension of the microbiota-gut-brain axis will foster the development of effective therapeutic interventions for the management of neurodegenerative diseases.
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Affiliation(s)
- Jian Sheng Loh
- School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor, Malaysia
| | - Wen Qi Mak
- School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor, Malaysia
| | - Li Kar Stella Tan
- School of Pharmacy, Faculty of Health & Medical Sciences, Taylor's University, 1, Jalan Taylors, Subang Jaya, 47500, Selangor, Malaysia
- Digital Health & Medical Advancements, Taylor's University, 1, Jalan Taylors, Subang Jaya, 47500, Selangor, Malaysia
| | - Chu Xin Ng
- School of Biosciences, Faculty of Health & Medical Sciences, Taylor's University, 1, Jalan Taylors, Subang Jaya, 47500, Selangor, Malaysia
| | - Hong Hao Chan
- School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor, Malaysia
| | - Shiau Hueh Yeow
- UCL School of Pharmacy, University College London, 29-39 Brunswick Square, London, WC1N 1AX, UK
| | - Jhi Biau Foo
- School of Pharmacy, Faculty of Health & Medical Sciences, Taylor's University, 1, Jalan Taylors, Subang Jaya, 47500, Selangor, Malaysia
- Digital Health & Medical Advancements, Taylor's University, 1, Jalan Taylors, Subang Jaya, 47500, Selangor, Malaysia
| | - Yong Sze Ong
- School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor, Malaysia
| | - Chee Wun How
- School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor, Malaysia.
| | - Kooi Yeong Khaw
- School of Pharmacy, Monash University Malaysia, Jalan Lagoon Selatan, 47500, Bandar Sunway, Selangor, Malaysia.
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De Sousa RAL, Cassilhas RC. Microglia role as the regulator of cognitive function. REVISTA DA ASSOCIACAO MEDICA BRASILEIRA (1992) 2023; 69:e20230412. [PMID: 37466612 PMCID: PMC10352012 DOI: 10.1590/1806-9282.20230412] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2023] [Accepted: 04/23/2023] [Indexed: 07/20/2023]
Affiliation(s)
- Ricardo Augusto Leoni De Sousa
- Universidade Federal dos Vales do Jequitinhonha e Mucuri, Physical Education Department - Diamantina (MG), Brazil
- Universidade Federal dos Vales do Jequitinhonha e Mucuri, Neuroscience and Exercise Study Group - Diamantina (MG), Brazil
| | - Ricardo Cardoso Cassilhas
- Universidade Federal dos Vales do Jequitinhonha e Mucuri, Physical Education Department - Diamantina (MG), Brazil
- Universidade Federal dos Vales do Jequitinhonha e Mucuri, Neuroscience and Exercise Study Group - Diamantina (MG), Brazil
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Kaiser KA, Kadish I, van Groen T, Smith DL, Dickinson S, Henschel B, Parker ES, Brown AW, Allison DB. The effect of a pharmaceutical ghrelin agonist on lifespan in C57BL/6J male mice: A controlled experiment. Aging Cell 2023; 22:e13787. [PMID: 36734122 PMCID: PMC10086516 DOI: 10.1111/acel.13787] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 12/14/2022] [Accepted: 01/05/2023] [Indexed: 02/04/2023] Open
Abstract
Interventions for animal lifespan extension like caloric restriction (CR) have identified physiologic and biochemical pathways related to hunger and energy-sensing status as possible contributors, but mechanisms have not been fully elucidated. Prior studies using ghrelin agonists show greater food intake but no effect on lifespan in rodent models. This experiment in male C57BL/6J mice tested the influence of ghrelin agonism for perceived hunger, in the absence of CR, on longevity. Mice aged 4 weeks were allowed to acclimate for 2 weeks prior to being assigned (N = 60/group). Prior to lights off daily (12:12 cycle), animals were fed a ghrelin agonist pill (LY444711; Eli Lilly) or a placebo control (Ctrl) until death. Treatment (GhrAg) animals were pair-fed daily based on the group mean food intake consumed by Ctrl (ad libitum feeding) the prior week. Results indicate an increased lifespan effect (log-rank p = 0.0032) for GhrAg versus placebo Ctrl, which weighed significantly more than GhrAg (adjusted for baseline weight). Further studies are needed to determine the full scope of effects of this ghrelin agonist, either directly via increased ghrelin receptor signaling or indirectly via other hypothalamic, systemic, or tissue-specific mechanisms.
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Affiliation(s)
- Kathryn A. Kaiser
- Department of Health Behavior, School of Public HealthUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Inga Kadish
- Department of Cell, Developmental and Integrative Biology, School of MedicineUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Thomas van Groen
- Department of Cell, Developmental and Integrative Biology, School of MedicineUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Daniel L. Smith
- Department of Nutrition Sciences, School of Health ProfessionsUniversity of Alabama at BirminghamBirminghamAlabamaUSA
| | - Stephanie Dickinson
- Department of Epidemiology and Biostatistics, School of Public HealthIndiana University‐BloomingtonBloomingtonIndianaUSA
| | - Beate Henschel
- Department of Epidemiology and Biostatistics, School of Public HealthIndiana University‐BloomingtonBloomingtonIndianaUSA
| | - Erik S. Parker
- Department of Epidemiology and Biostatistics, School of Public HealthIndiana University‐BloomingtonBloomingtonIndianaUSA
| | - Andrew W. Brown
- Department of BiostatisticsUniversity of Arkansas for Medical SciencesLittle RockArkansasUSA
| | - David B. Allison
- Department of Epidemiology and Biostatistics, School of Public HealthIndiana University‐BloomingtonBloomingtonIndianaUSA
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Cognitive Dysfunction, an Increasingly Valued Long-Term Impairment in Acromegaly. J Clin Med 2023; 12:jcm12062283. [PMID: 36983284 PMCID: PMC10058029 DOI: 10.3390/jcm12062283] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2023] [Revised: 02/26/2023] [Accepted: 03/08/2023] [Indexed: 03/17/2023] Open
Abstract
Acromegaly is a chronic disease caused by the overproduction of growth hormone (GH) and accompanying insulin-like growth factor-1 (IGF-1), which is often caused by GH-secreting pituitary adenomas. In addition to its somatic burden, a growing number of studies have found that patients suffering from acromegaly exhibit psychosocial and personality changes. Over the past 70 years, there has been increasing interest in the cognitive impairment and neuropsychological issues of patients with acromegaly, and a variety of neuropsychological and neurophysiological tests have been used to measure cognitive changes in patients. The impact of disease progression status, treatment modalities, and various comorbidities on cognitive function and the mechanisms of cognitive impairment in patients with acromegaly are therefore outlined in this review. Multidisciplinary assessment has important implications for the management of acromegaly, particularly in relation to cognitive function. Here, we summarize the relevant literature concerning cognitive-behavioral research on acromegaly to demonstrate the impact of long-term impairment caused by GH and IGF-1 on the cognitive behavior of patients.
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Ghrelin/GHS-R1A antagonism in memory test and its effects on central molecular signaling involved in addiction in rats. Pharmacol Biochem Behav 2023; 224:173528. [PMID: 36870422 DOI: 10.1016/j.pbb.2023.173528] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/23/2022] [Revised: 12/23/2022] [Accepted: 02/12/2023] [Indexed: 03/06/2023]
Abstract
Central ghrelin signaling seems to play important role in addiction as well as memory processing. Antagonism of the growth hormone secretagogue receptor (GHS-R1A) has been recently proposed as a promising tool for the unsatisfactory drug addiction therapy. However, molecular aspects of GHS-R1A involvement in specific brain regions remain unclear. The present study demonstrated for the first time that acute as well as subchronic (4 days) administration of the experimental GHS-R1A antagonist JMV2959 in usual intraperitoneal doses including 3 mg/kg, had no influence on memory functions tested in the Morris Water Maze in rats as well as no significant effects on the molecular markers linked with memory processing in selected brain areas in rats, specifically on the β-actin, c-Fos, two forms of the calcium/calmodulin-dependent protein kinase II (CaMKII, p-CaMKII) and the cAMP-response element binding protein (CREB, p-CREB), within the medial prefrontal cortex (mPFC), nucleus accumbens (NAc), dorsal striatum, and hippocampus (HIPP). Furthermore, following the methamphetamine intravenous self-administration in rats, the 3 mg/kg JMV2959 pretreatment significantly reduced or prevented the methamphetamine-induced significant decrease of hippocampal β-actin and c-Fos as well as it prevented the significant decrease of CREB in the NAC and mPFC. These results imply, that the GHS-R1A antagonist/JMV2959 might reduce/prevent some of the memory-linked molecular changes elicited by methamphetamine addiction within brain structures associated with memory (HIPP), reward (NAc), and motivation (mPFC), which may contribute to the previously observed significant JMV2959-induced reduction of the methamphetamine self-administration and drug-seeking behavior in the same animals. Further research is necessary to corroborate these results.
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Ghrelin system in Alzheimer's disease. Curr Opin Neurobiol 2023; 78:102655. [PMID: 36527939 PMCID: PMC10395051 DOI: 10.1016/j.conb.2022.102655] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/17/2022] [Accepted: 11/16/2022] [Indexed: 12/23/2022]
Abstract
Alzheimer's disease (AD) is the most common type of dementia in seniors. Current efforts to understand the etiopathogenesis of this neurodegenerative disorder have brought forth questions about systemic factors in the development of AD. Ghrelin is a brain-gut peptide that is activated by ghrelin O-acyltransferase (GOAT) and signals via its receptor, growth hormone secretagogue receptor (GHSR). With increasing recognition of the neurotropic effects of ghrelin, the role of ghrelin system deregulation in the development of AD has been accentuated in recent years. In this review, we summarized recent research progress regarding the mechanisms of ghrelin signaling dysregulation and its contribution to AD brain pathology. In addition, we also discussed the therapeutic potential of strategies targeting ghrelin signaling for the treatment of this neurological disease.
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Tian J, Du E, Jia K, Wang T, Guo L, Zigman JM, Du H. Elevated Ghrelin Promotes Hippocampal Ghrelin Receptor Defects in Humanized Amyloid-β Knockin Mice During Aging. J Alzheimers Dis 2023; 96:1579-1592. [PMID: 38007666 PMCID: PMC10841720 DOI: 10.3233/jad-231002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2023]
Abstract
BACKGROUND Emerging evidence has revealed that dysregulation of the hormone ghrelin and its receptor, growth hormone secretagogue receptor (GHSR), contributes to the pathogenesis of Alzheimer's disease (AD). Specifically, defective GHSR function and resultant hippocampal ghrelin resistance are linked to hippocampal synaptic injury in AD paradigms. Also, AD patients exhibit elevated ghrelin activation. However, the detailed molecular mechanisms of hippocampal GHSR dysfunction and the relevance of ghrelin elevation to hippocampal ghrelin resistance in AD-relevant pathological settings are not fully understood. OBJECTIVE In the current study, we employed a recently established mouse line of AD risk [humanized amyloid beta knockin (hAβ KI mice), also referred to as a mouse model of late-onset AD in previous literature] to further define the role of ghrelin system dysregulation in the development of AD. METHODS We employed multidisciplinary techniques to determine the change of plasma ghrelin and the functional status of GHSR in hAβ KI mice as well as primary neuron cultures. RESULTS We observed concurrent plasma ghrelin elevation and hippocampal GHSR desensitization with disease progression. Further examination excluded the possibility that ghrelin elevation is a compensatory change in response to GHSR dysfunction. In contrast, further in vitro and in vivo results show that agonist-mediated overstimulation potentiates GHSR desensitization through enhanced GHSR internalization. CONCLUSIONS These findings suggest that circulating ghrelin elevation is a pathological event underlying hippocampal GHSR dysfunction, culminating in hippocampal ghrelin resistance and resultant synaptic injury in late-onset AD-related settings.
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Affiliation(s)
- Jing Tian
- Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, KS, USA
| | - Eric Du
- Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, KS, USA
- Blue Valley West High School, Overland Park, KS, USA
| | - Kun Jia
- Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, KS, USA
| | - Tienju Wang
- Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, KS, USA
| | - Lan Guo
- Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, KS, USA
| | - Jeffrey M. Zigman
- Department of Internal Medicine, Center for Hypothalamic Research, The University of Texas Southwestern Medical Center, Dallas, TX, USA
| | - Heng Du
- Department of Pharmacology and Toxicology, The University of Kansas, Lawrence, KS, USA
- Alzheimer’s disease Research Center (ADRC), Department of Neurology, The University of Kansas Medical Center, Kansas City, KS, USA
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Abstract
This review deals with an unwelcome reality about several forms of dementia, including Alzheimer's disease- that these dementias are caused, in part or whole, by the aging of the vasculature. Since the vasculature ages in us all, dementia is our fate, sealed by the realit!ies of the circulation; it is not a disease with a cure pending. Empirically, cognitive impairment before our 7th decade is uncommon and considered early, while a diagnosis in our 11th decade is late but common in that cohort (>40%). Projections from earlier ages suggest that the prevalence of dementia in people surviving into their 12th decade exceeds 80%. We address the question why so few of many interventions known to delay dementia are recognized as therapy; and we try to resolve this few-and-many paradox, identifying opportunities for better treatment, especially pre-diagnosis. The idea of dementia as a fate is resisted, we argue, because it negates the hope of a cure. But the price of that hope is lost opportunity. An approach more in line with the evidence, and more likely to limit suffering, is to understand the damage that accumulates with age in the cerebral vasculature and therefore in the brain, and which eventually gives rise to cognitive symptoms in late life, too often leading to dementia. We argue that hope should be redirected to delaying that damage and with it the onset of cognitive loss; and, for each individual, it should be redirected to a life-long defense of their brain.
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Affiliation(s)
- Marcus J Andersson
- Faculty of Medicine and Health, University of Sydney, Camperdown, NSW, Australia
| | - Jonathan Stone
- School of Medical Sciences and Faculty of Medicine and Health, University of Sydney, Camperdown, NSW, Australia
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Russo C, Valle MS, Russo A, Malaguarnera L. The Interplay between Ghrelin and Microglia in Neuroinflammation: Implications for Obesity and Neurodegenerative Diseases. Int J Mol Sci 2022; 23:ijms232113432. [PMID: 36362220 PMCID: PMC9654207 DOI: 10.3390/ijms232113432] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2022] [Revised: 10/29/2022] [Accepted: 11/01/2022] [Indexed: 11/06/2022] Open
Abstract
Numerous studies have shown that microglia are capable of producing a wide range of chemokines to promote inflammatory processes within the central nervous system (CNS). These cells share many phenotypical and functional characteristics with macrophages, suggesting that microglia participate in innate immune responses in the brain. Neuroinflammation induces neurometabolic alterations and increases in energy consumption. Microglia may constitute an important therapeutic target in neuroinflammation. Recent research has attempted to clarify the role of Ghre signaling in microglia on the regulation of energy balance, obesity, neuroinflammation and the occurrence of neurodegenerative diseases. These studies strongly suggest that Ghre modulates microglia activity and thus affects the pathophysiology of neurodegenerative diseases. This review aims to summarize what is known from the current literature on the way in which Ghre modulates microglial activity during neuroinflammation and their impact on neurometabolic alterations in neurodegenerative diseases. Understanding the role of Ghre in microglial activation/inhibition regulation could provide promising strategies for downregulating neuroinflammation and consequently for diminishing negative neurological outcomes.
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Affiliation(s)
- Cristina Russo
- Section of Pathology, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, 95123 Catania, Italy
| | - Maria Stella Valle
- Laboratory of Neuro-Biomechanics, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, 95123 Catania, Italy
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
| | - Antonella Russo
- Section of Physiology, Department of Biomedical and Biotechnological Sciences, University of Catania, 95123 Catania, Italy
| | - Lucia Malaguarnera
- Section of Pathology, Department of Biomedical and Biotechnological Sciences, School of Medicine, University of Catania, 95123 Catania, Italy
- Correspondence:
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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]
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Ouellette AR, Hadad N, Deighan A, Robinson L, O'Connell K, Freund A, Churchill GA, Kaczorowski CC. Life-long dietary restrictions have negligible or damaging effects on late-life cognitive performance: A key role for genetics in outcomes. Neurobiol Aging 2022; 118:108-116. [PMID: 35914473 PMCID: PMC9583241 DOI: 10.1016/j.neurobiolaging.2022.07.004] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2022] [Revised: 06/22/2022] [Accepted: 07/07/2022] [Indexed: 11/21/2022]
Abstract
Several studies report that caloric restriction (CR) or intermittent fasting (IF) can improve cognition, while others report limited or no cognitive benefits. Here, we compare the effects of 20% CR, 40% CR, 1-day IF, and 2-day IF feeding paradigms to ad libitum controls on Y-maze working memory (WM) and contextual fear memory (CFM) in a large population of Diversity Outbred mice that model the genetic diversity of humans. While CR and IF interventions improve lifespan, we observed no enhancement of working memory or CFM in mice on these feeding paradigms, and report 40% CR to be damaging to recall of CFM. Using Quantitative Trait Loci mapping, we identified the gene Slc16a7 to be associated with CFM outcomes in aged mice on lifespan promoting feeding paradigms. Limited utility of dieting and fasting on memory in mice that recapitulate genetic diversity in the human population highlights the need for anti-aging therapeutics that promote cognitive function, with the neuronal monocarboxylate transporter MCT2 encoded by Slc16a7 highlighted as novel target.
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Affiliation(s)
- Andrew R Ouellette
- The University of Maine, Graduate School of Biomedical Science and Engineering, Orono ME, USA; The Jackson Laboratory, Bar Harbor ME, USA
| | | | | | | | | | - Adam Freund
- Calico Life Sciences LLC, San Francisco CA, USA
| | | | - Catherine C Kaczorowski
- The University of Maine, Graduate School of Biomedical Science and Engineering, Orono ME, USA; The Jackson Laboratory, Bar Harbor ME, USA.
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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.
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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.
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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
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Shepherd A, Zhang T, Hoffmann LB, Zeleznikow-Johnston AM, Churilov L, Hannan AJ, Burrows EL. A Preclinical Model of Computerized Cognitive Training: Touchscreen Cognitive Testing Enhances Cognition and Hippocampal Cellular Plasticity in Wildtype and Alzheimer's Disease Mice. Front Behav Neurosci 2021; 15:766745. [PMID: 34938165 PMCID: PMC8685297 DOI: 10.3389/fnbeh.2021.766745] [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: 08/30/2021] [Accepted: 11/12/2021] [Indexed: 11/29/2022] Open
Abstract
With the growing popularity of touchscreen cognitive testing in rodents, it is imperative to understand the fundamental effects exposure to this paradigm can have on the animals involved. In this study, we set out to assess hippocampal-dependant learning in the APP/PS1 mouse model of Alzheimer’s disease (AD) on two highly translatable touchscreen tasks – the Paired Associate Learning (PAL) task and the Trial Unique Non-Matching to Location (TUNL) task. Both of these tests are based on human tasks from the Cambridge Neuropsychological Test Automated Battery (CANTAB) and are sensitive to deficits in both mild cognitive impairment (MCI) and AD. Mice were assessed for deficits in PAL at 9–12 months of age, then on TUNL at 8–11 and 13–16 months. No cognitive deficits were evident in APP/PS1 mice at any age, contrary to previous reports using maze-based learning and memory tasks. We hypothesized that daily and long-term touchscreen training may have inadvertently acted as a cognitive enhancer. When touchscreen-tested mice were assessed on the Morris water maze, they showed improved task acquisition compared to naïve APP/PS1 mice and wild-type (WT) littermate controls. In addition, we show that touchscreen-trained WT and APP/PS1 mice show increased cell proliferation and immature neuron numbers in the dentate gyrus compared to behaviorally naïve WT and APP/PS1 mice. This result indicates that the touchscreen testing paradigm could improve cognitive performance, and/or mask an impairment, in experimental mouse models. This touchscreen-induced cognitive enhancement may involve increased neurogenesis, and possibly other forms of cellular plasticity. This is the first study to show increased numbers of proliferating cells and immature neurons in the hippocampus following touchscreen testing, and that touchscreen training can improve cognitive performance in maze-based spatial navigation tasks. This potential for touchscreen testing to induce cognitive enhancement, or other phenotypic shifts, in preclinical models should be considered in study design. Furthermore, touchscreen-mediated cognitive enhancement could have therapeutic implications for cognitive disorders.
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Affiliation(s)
- Amy Shepherd
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC, Australia
| | - Tracy Zhang
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC, Australia
| | - Lucas B Hoffmann
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC, Australia
| | - Ariel M Zeleznikow-Johnston
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC, Australia
| | - Leonid Churilov
- Melbourne Medical School, The University of Melbourne, Parkville, VIC, Australia
| | - Anthony J Hannan
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC, Australia.,Department of Anatomy and Neuroscience, The University of Melbourne, Parkville, VIC, Australia
| | - Emma L Burrows
- Florey Institute of Neuroscience and Mental Health, Melbourne Brain Centre, University of Melbourne, Parkville, VIC, Australia
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15
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Nagaoka U, Shimizu T, Uchihara T, Komori T, Hosoda H, Takahashi K. Decreased plasma ghrelin in male ALS patients is associated with poor prognosis. Neurosci Res 2021; 177:111-117. [PMID: 34823917 DOI: 10.1016/j.neures.2021.11.003] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2021] [Revised: 11/12/2021] [Accepted: 11/15/2021] [Indexed: 11/19/2022]
Abstract
Physiological changes including altered nutritional status influence disease progression and survival in patients with amyotrophic lateral sclerosis (ALS). Ghrelin affects the nutritional status by regulating appetite and energy expenditure, and also has neuroprotective effects. To investigate the association between ghrelin and ALS prognosis, we analyzed plasma acylated-ghrelin levels in 33 patients with ALS. Compared among ALS patients, male had lower plasma ghrelin levels than female, although disease specificity is unknown. ALS patients, especially male ALS patients, with low plasma ghrelin levels (<15 fmol/mL) had significantly shorter post-examination survival times than those with high plasma ghrelin levels (≥15 fmol/mL). Univariate and multivariate analyses revealed a significant effect of ghrelin levels on post-examination survival. Immunohistochemical study of autopsied stomach samples from 8 of 33 patients revealed that the population of ghrelin-positive cells tended to be reduced in the low-plasma ghrelin group than in the high-plasma ghrelin group. Our findings suggest that ghrelin levels are an independent predictor of survival in ALS, especially male ALS patients, and the ghrelin-positive cells may decrease in ALS with low plasma ghrelin. Thus, reduced ghrelin secretion may be associated with poor prognosis among patients with ALS.
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Affiliation(s)
- Utako Nagaoka
- Department of Neurology, Tokyo Metropolitan Neurological Hospital, Tokyo, 183-0042, Japan.
| | - Toshio Shimizu
- Department of Neurology, Tokyo Metropolitan Neurological Hospital, Tokyo, 183-0042, Japan
| | - Toshiki Uchihara
- Laboratory of Structural Neuropathology, Tokyo Metropolitan Institute of Medical Science, Tokyo, 156-8506, Japan; Department of Neurology, Nitobe Memorial Nakano General Hospital, Tokyo, 164-8607, Japan
| | - Takashi Komori
- Laboratory Medicine and Pathology, Tokyo Metropolitan Neurological Hospital, Tokyo, 183-0042, Japan
| | - Hiroshi Hosoda
- Department of Regenerative Medicine and Tissue Engineering, National Cerebral and Cardiovascular Center Research Institute, Osaka, 564-8565, Japan
| | - Kazushi Takahashi
- Department of Neurology, Tokyo Metropolitan Neurological Hospital, Tokyo, 183-0042, Japan
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16
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Ntsapi CM, Loos B. Neurons die with heightened but functional macro- and chaperone mediated autophagy upon increased amyloid-ß induced toxicity with region-specific protection in prolonged intermittent fasting. Exp Cell Res 2021; 408:112840. [PMID: 34624324 DOI: 10.1016/j.yexcr.2021.112840] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2021] [Revised: 08/30/2021] [Accepted: 09/22/2021] [Indexed: 01/07/2023]
Abstract
Alzheimer's disease (AD) is a devastating neurodegenerative condition with significant socio-economic impact that is exacerbated by the rapid increase in population aging, particularly impacting already burdened health care systems of poorly resourced countries. Accumulation of the amyloid-β (Aβ) peptide, generated through amyloid precursor protein (APP) processing, manifesting in senile plaques, is a well-established neuropathological feature. Aβ plays a key role in driving synaptic dysfunction, neuronal cell loss, glial cell activation and oxidative stress associated with the pathogenesis of AD. Thus, the enhanced clearance of Aβ peptide though modulation of the mechanisms that regulate intracellular Aβ metabolism and clearance during AD progression have received major attention. Autophagy, a lysosome-based major proteolytic pathway, plays a crucial role in intracellular protein quality control and has been shown to contribute to the clearance of Aβ peptide. However, to what extent autophagy activity remains upregulated and functional in the process of increasing Aβ neurotoxicity is largely unclear. Here, we investigated the extent of neuronal toxicity in vitro by characterising autophagic flux, the expression profile of key amyloidogenic proteins, and proteins associated with prominent subtypes of the autophagy pathway to dissect the interplay between the engagement of proteolytic pathways and cell death onset in the context of APP overexpression. Moreover, we assessed the neuroprotective effects of a caloric restriction regime in vivo on the modulation of autophagy in specific brain regions. Our results reveal that autophagy is upregulated in the presence of high levels of APP and Aβ and remains heightened and functional despite concomitant apoptosis induction, suggestive of a mismatch between autophagy cargo generation and clearance capacity. These findings were confirmed when implementing a prolonged intermittent fasting (IF) intervention in a model of paraquat-induced neuronal toxicity, where markers of autophagic activity were increased, while apoptosis onset and lipid peroxidation were robustly decreased in brain regions associated with neurodegeneration. This work highlights that especially caloric restriction mimetics and controlled prolonged IF may indeed be a highly promising therapeutic strategy at all stages of AD-associated pathology progression, for a cell-inherent and cell specific augmentation of Aβ clearance through the powerful engagement of autophagy and thereby robustly contributing to neuronal protection.
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Affiliation(s)
| | - Ben Loos
- Department of Physiological Sciences, Stellenbosch University, South Africa.
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17
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Rojas M, Chávez-Castillo M, Bautista J, Ortega Á, Nava M, Salazar J, Díaz-Camargo E, Medina O, Rojas-Quintero J, Bermúdez V. Alzheimer’s disease and type 2 diabetes mellitus: Pathophysiologic and pharmacotherapeutics links. World J Diabetes 2021; 12:745-766. [PMID: 34168725 PMCID: PMC8192246 DOI: 10.4239/wjd.v12.i6.745] [Citation(s) in RCA: 32] [Impact Index Per Article: 10.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/13/2021] [Revised: 03/20/2021] [Accepted: 05/21/2021] [Indexed: 02/06/2023] Open
Abstract
At present, Alzheimer’s disease (AD) and type 2 diabetes mellitus (T2DM) are two highly prevalent disorders worldwide, especially among elderly individuals. T2DM appears to be associated with cognitive dysfunction, with a higher risk of developing neurocognitive disorders, including AD. These diseases have been observed to share various pathophysiological mechanisms, including alterations in insulin signaling, defects in glucose transporters (GLUTs), and mitochondrial dysfunctions in the brain. Therefore, the aim of this review is to summarize the current knowledge regarding the molecular mechanisms implicated in the association of these pathologies as well as recent therapeutic alternatives. In this context, the hyperphosphorylation of tau and the formation of neurofibrillary tangles have been associated with the dysfunction of the phosphatidylinositol 3-kinase and mitogen-activated protein kinase pathways in the nervous tissues as well as the decrease in the expression of GLUT-1 and GLUT-3 in the different areas of the brain, increase in reactive oxygen species, and production of mitochondrial alterations that occur in T2DM. These findings have contributed to the implementation of overlapping pharmacological interventions based on the use of insulin and antidiabetic drugs, or, more recently, azeliragon, amylin, among others, which have shown possible beneficial effects in diabetic patients diagnosed with AD.
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Affiliation(s)
- Milagros Rojas
- Endocrine and Metabolic Diseases Research Center, School of Medicine, University of Zulia, Maracaibo 4004, Venezuela
| | - Mervin Chávez-Castillo
- Endocrine and Metabolic Diseases Research Center, School of Medicine, University of Zulia, Maracaibo 4004, Venezuela
| | - Jordan Bautista
- Endocrine and Metabolic Diseases Research Center, School of Medicine, University of Zulia, Maracaibo 4004, Venezuela
| | - Ángel Ortega
- Endocrine and Metabolic Diseases Research Center, School of Medicine, University of Zulia, Maracaibo 4004, Venezuela
| | - Manuel Nava
- Endocrine and Metabolic Diseases Research Center, School of Medicine, University of Zulia, Maracaibo 4004, Venezuela
| | - Juan Salazar
- Endocrine and Metabolic Diseases Research Center, School of Medicine, University of Zulia, Maracaibo 4004, Venezuela
| | - Edgar Díaz-Camargo
- Universidad Simón Bolívar, Facultad de Ciencias Jurídicas y Sociales, Cúcuta 540006, Colombia
| | - Oscar Medina
- Universidad Simón Bolívar, Facultad de Ciencias Jurídicas y Sociales, Cúcuta 540006, Colombia
| | - Joselyn Rojas-Quintero
- Pulmonary and Critical Care Medicine Department, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02155, United States
| | - Valmore Bermúdez
- Universidad Simón Bolívar, Facultad de Ciencias de la Salud, Barranquilla 080001, Colombia
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18
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Childhood Circumstances and Mental Health in Old Age: A Life Course Survey in China. INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2021; 18:ijerph18126420. [PMID: 34198481 PMCID: PMC8296235 DOI: 10.3390/ijerph18126420] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/23/2021] [Revised: 06/09/2021] [Accepted: 06/10/2021] [Indexed: 11/16/2022]
Abstract
Current evidence and research of the life course approach on the association between life experiences and health in old age are fragmentary. This paper empirically examines the “long arm” effect of the childhood circumstances on mental health in later life using a large longitudinal dataset (CHARLS) conducted in 2014 and 2015. We operationalize the childhood circumstances as family economic conditions, community environment, and peer network to include the meaningful content and understand their interaction. The SEM results indicate that effects of those factors contributing to older people’s mental health are unequal and vary among age groups and genders. Of those, peer network in childhood determines to a large extent the mental health through the whole life course, while economic conditions and community environment are weakly associated with mental health. Furthermore, we find a distinct interaction mechanism linking those variables. The peer network completely mediates the effect of the community environment on the mental health of older adults and has a partial mediating effect on the economic conditions. Those findings suggest that social policies aimed at promoting older people’s mental health in the context of the active ageing and health ageing strategy should go beyond the old age stage and target social conditions early in childhood.
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19
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Saré RM, Lemons A, Smith CB. Behavior Testing in Rodents: Highlighting Potential Confounds Affecting Variability and Reproducibility. Brain Sci 2021; 11:brainsci11040522. [PMID: 33924037 PMCID: PMC8073298 DOI: 10.3390/brainsci11040522] [Citation(s) in RCA: 46] [Impact Index Per Article: 15.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2021] [Revised: 04/05/2021] [Accepted: 04/08/2021] [Indexed: 12/17/2022] Open
Abstract
Rodent models of brain disorders including neurodevelopmental, neuropsychiatric, and neurodegenerative diseases are essential for increasing our understanding of underlying pathology and for preclinical testing of potential treatments. Some of the most important outcome measures in such studies are behavioral. Unfortunately, reports from different labs are often conflicting, and preclinical studies in rodent models are not often corroborated in human trials. There are many well-established tests for assessing various behavioral readouts, but subtle aspects can influence measurements. Features such as housing conditions, conditions of testing, and the sex and strain of the animals can all have effects on tests of behavior. In the conduct of behavior testing, it is important to keep these features in mind to ensure the reliability and reproducibility of results. In this review, we highlight factors that we and others have encountered that can influence behavioral measures. Our goal is to increase awareness of factors that can affect behavior in rodents and to emphasize the need for detailed reporting of methods.
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20
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Mathur N, Mehdi SF, Anipindi M, Aziz M, Khan SA, Kondakindi H, Lowell B, Wang P, Roth J. Ghrelin as an Anti-Sepsis Peptide: Review. Front Immunol 2021; 11:610363. [PMID: 33584688 PMCID: PMC7876230 DOI: 10.3389/fimmu.2020.610363] [Citation(s) in RCA: 19] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/25/2020] [Accepted: 12/09/2020] [Indexed: 12/15/2022] Open
Abstract
Sepsis continues to produce widespread inflammation, illness, and death, prompting intensive research aimed at uncovering causes and therapies. In this article, we focus on ghrelin, an endogenous peptide with promise as a potent anti-inflammatory agent. Ghrelin was discovered, tracked, and isolated from stomach cells based on its ability to stimulate release of growth hormone. It also stimulates appetite and is shown to be anti-inflammatory in a wide range of tissues. The anti-inflammatory effects mediated by ghrelin are a result of both the stimulation of anti-inflammatory processes and an inhibition of pro-inflammatory forces. Anti-inflammatory processes are promoted in a broad range of tissues including the hypothalamus and vagus nerve as well as in a broad range of immune cells. Aged rodents have reduced levels of growth hormone (GH) and diminished immune responses; ghrelin administration boosts GH levels and immune response. The anti-inflammatory functions of ghrelin, well displayed in preclinical animal models of sepsis, are just being charted in patients, with expectations that ghrelin and growth hormone might improve outcomes in patients with sepsis.
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Affiliation(s)
- Nimisha Mathur
- Laboratory of Diabetes, Obesity, and Other Metabolic Disorders, The Feinstein Institutes for Medical Research, Manhasset, NY, United States
| | - Syed F. Mehdi
- Laboratory of Diabetes, Obesity, and Other Metabolic Disorders, The Feinstein Institutes for Medical Research, Manhasset, NY, United States
| | - Manasa Anipindi
- Laboratory of Diabetes, Obesity, and Other Metabolic Disorders, The Feinstein Institutes for Medical Research, Manhasset, NY, United States
| | - Monowar Aziz
- Laboratory of Diabetes, Obesity, and Other Metabolic Disorders, The Feinstein Institutes for Medical Research, Manhasset, NY, United States
- Center for Immunology and Inflammation, The Feinstein Institutes for Medical Research, Manhasset, NY, United States
| | - Sawleha A. Khan
- Laboratory of Diabetes, Obesity, and Other Metabolic Disorders, The Feinstein Institutes for Medical Research, Manhasset, NY, United States
| | - Hema Kondakindi
- Laboratory of Diabetes, Obesity, and Other Metabolic Disorders, The Feinstein Institutes for Medical Research, Manhasset, NY, United States
| | - Barbara Lowell
- Laboratory of Diabetes, Obesity, and Other Metabolic Disorders, The Feinstein Institutes for Medical Research, Manhasset, NY, United States
| | - Ping Wang
- Laboratory of Diabetes, Obesity, and Other Metabolic Disorders, The Feinstein Institutes for Medical Research, Manhasset, NY, United States
- Center for Immunology and Inflammation, The Feinstein Institutes for Medical Research, Manhasset, NY, United States
| | - Jesse Roth
- Laboratory of Diabetes, Obesity, and Other Metabolic Disorders, The Feinstein Institutes for Medical Research, Manhasset, NY, United States
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21
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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: 28] [Impact Index Per Article: 7.0] [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.
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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
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22
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Bittencourt A, Brum PO, Ribeiro CT, Gasparotto J, Bortolin RC, de Vargas AR, Heimfarth L, de Almeida RF, Moreira JCF, de Oliveira J, Gelain DP. High fat diet-induced obesity causes a reduction in brain tyrosine hydroxylase levels and non-motor features in rats through metabolic dysfunction, neuroinflammation and oxidative stress. Nutr Neurosci 2020; 25:1026-1040. [PMID: 33078695 DOI: 10.1080/1028415x.2020.1831261] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/12/2023]
Abstract
Obesity is a health problem that has been associated with neuroinflammation, decreased cognitive functions and development of neurodegenerative diseases. Parkinson's disease (PD) is a chronic neurodegenerative condition characterized by motor and non-motor abnormalities, increased brain inflammation, α-synuclein protein aggregation and dopaminergic neuron loss that is associated with decreased levels of tyrosine hydroxylase (TH) in the brain. Diet-induced obesity is a global epidemic and its role as a risk factor for PD is not clear. Herein, we showed that 25 weeks on a high-fat diet (HFD) promotes significant alterations in the nigrostriatal axis of Wistar rats. Obesity induced by HFD exposure caused a reduction in TH levels and increased TH phosphorylation at serine 40 in the ventral tegmental area. These effects were associated with insulin resistance, increased tumor necrosis factor-α levels, oxidative stress, astrogliosis and microglia activation. No difference was detected in the levels of α-synuclein. Obesity also induced impairment of locomotor activity, total mobility and anxiety-related behaviors that were identified in the open-field and light/dark tasks. There were no changes in motor coordination or memory. Together, these data suggest that the reduction of TH levels in the nigrostriatal axis occurs through an α-synuclein-independent pathway and can be attributed to brain inflammation, oxidative/nitrosative stress and metabolic disorders induced by obesity.
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Affiliation(s)
- Aline Bittencourt
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Pedro Ozorio Brum
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Camila Tiefensee Ribeiro
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Juciano Gasparotto
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Rafael Calixto Bortolin
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.,Departamento de Ingeniería Civil y Ambiental, Universidad de la Costa, Barranquilla, Atlántico, Colombia
| | - Amanda Rodrigues de Vargas
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Luana Heimfarth
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Roberto Farina de Almeida
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - José Claudio Fonseca Moreira
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Jade de Oliveira
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
| | - Daniel Pens Gelain
- Departamento de Bioquímica, Instituto de Ciências Básicas da Saúde, universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil
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23
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Kim S, Nam Y, Shin SJ, Park YH, Jeon SG, Kim JI, Kim MJ, Moon M. The Potential Roles of Ghrelin in Metabolic Syndrome and Secondary Symptoms of Alzheimer's Disease. Front Neurosci 2020; 14:583097. [PMID: 33071750 PMCID: PMC7543232 DOI: 10.3389/fnins.2020.583097] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/15/2020] [Accepted: 08/26/2020] [Indexed: 12/12/2022] Open
Abstract
Although the major causative factors of Alzheimer's disease (AD) are the accumulation of amyloid β and hyperphosphorylated tau, AD can also be caused by metabolic dysfunction. The major clinical symptom of AD is cognitive dysfunction. However, AD is also accompanied by various secondary symptoms such as depression, sleep-wake disturbances, and abnormal eating behaviors. Interestingly, the orexigenic hormone ghrelin has been suggested to have beneficial effects on AD-related metabolic syndrome and secondary symptoms. Ghrelin improves lipid distribution and alters insulin sensitivity, effects that are hypothesized to delay the progression of AD. Furthermore, ghrelin can relieve depression by enhancing the secretion of hormones such as serotonin, noradrenaline, and orexin. Moreover, ghrelin can upregulate the expression of neurotrophic factors such as brain-derived neurotrophic factor and modulate the release of proinflammatory cytokines such as tumor necrosis factor α and interleukin 1β. Ghrelin alleviates sleep-wake disturbances by increasing the levels of melatonin, melanin-concentrating hormone. Ghrelin reduces the risk of abnormal eating behaviors by increasing neuropeptide Y and γ-aminobutyric acid. In addition, ghrelin increases food intake by inhibiting fatty acid biosynthesis. However, despite the numerous studies on the role of ghrelin in the AD-related pathology and metabolic disorders, there are only a few studies that investigate the effects of ghrelin on secondary symptoms associated with AD. In this mini review, our purpose is to provide the insights of future study by organizing the previous studies for the role of ghrelin in AD-related pathology and metabolic disorders.
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Affiliation(s)
- Sujin Kim
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Yunkwon Nam
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Soo Jung Shin
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Yong Ho Park
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Seong Gak Jeon
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea.,Department of Neural Development and Disease, Korea Brain Research Institute (KBRI), Daegu, South Korea
| | - Jin-Il Kim
- Department of Nursing, College of Nursing, Jeju National University, Jeju-si, South Korea
| | - Min-Jeong Kim
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
| | - Minho Moon
- Department of Biochemistry, College of Medicine, Konyang University, Daejeon, South Korea
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24
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Tian J, Guo L, Sui S, Driskill C, Phensy A, Wang Q, Gauba E, Zigman JM, Swerdlow RH, Kroener S, Du H. Disrupted hippocampal growth hormone secretagogue receptor 1α interaction with dopamine receptor D1 plays a role in Alzheimer's disease. Sci Transl Med 2020; 11:11/505/eaav6278. [PMID: 31413143 PMCID: PMC6776822 DOI: 10.1126/scitranslmed.aav6278] [Citation(s) in RCA: 39] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2018] [Accepted: 06/24/2019] [Indexed: 12/12/2022]
Abstract
Hippocampal lesions are a defining pathology of Alzheimer's disease (AD). However, the molecular mechanisms that underlie hippocampal synaptic injury in AD have not been fully elucidated. Current therapeutic efforts for AD treatment are not effective in correcting hippocampal synaptic deficits. Growth hormone secretagogue receptor 1α (GHSR1α) is critical for hippocampal synaptic physiology. Here, we report that GHSR1α interaction with β-amyloid (Aβ) suppresses GHSR1α activation, leading to compromised GHSR1α regulation of dopamine receptor D1 (DRD1) in the hippocampus from patients with AD. The simultaneous application of the selective GHSR1α agonist MK0677 with the selective DRD1 agonist SKF81297 rescued Ghsr1α function from Aβ inhibition, mitigating hippocampal synaptic injury and improving spatial memory in an AD mouse model. Our data reveal a mechanism of hippocampal vulnerability in AD and suggest that a combined activation of GHSR1α and DRD1 may be a promising approach for treating AD.
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Affiliation(s)
- Jing Tian
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Lan Guo
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Shaomei Sui
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA.,Department of Neurology, Qianfoshan Hospital, Shandong First Medical University, Jinan, Shandong 250014, China
| | - Christopher Driskill
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Aarron Phensy
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Qi Wang
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA.,Department of Neurology, Qianfoshan Hospital, Shandong First Medical University, Jinan, Shandong 250014, China
| | - Esha Gauba
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Jeffrey M Zigman
- Department of Internal Medicine, Division of Hypothalamic Research, University of Texas Southwestern Medical Center, Dallas, TX 75390, USA
| | - Russell H Swerdlow
- Department of Neurology, University of Kansas Medical Center, Kansas City, KS 66160, USA
| | - Sven Kroener
- School of Behavioral and Brain Sciences, University of Texas at Dallas, Richardson, TX 75080, USA
| | - Heng Du
- Department of Biological Sciences, University of Texas at Dallas, Richardson, TX 75080, USA.
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25
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Yu Q, Zou L, Kong Z, Yang L. Cognitive Impact of Calorie Restriction: A Narrative Review. J Am Med Dir Assoc 2020; 21:1394-1401. [PMID: 32693996 DOI: 10.1016/j.jamda.2020.05.047] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2020] [Revised: 05/18/2020] [Accepted: 05/19/2020] [Indexed: 02/06/2023]
Abstract
The impairment of cognitive function can cause substantial emotional and financial burdens. A recent global increasing trend in cognitive impairment and associated disorders has been observed, which will continue to grow as the population ages rapidly. As a nonpharmaceutical approach, calorie restriction (CR) has received extensive research interests due to its health benefits, including maintaining cognitive function. In this narrative review, we first briefly introduce the role of cognitive function in activities of daily living and CR as a part of healthy lifestyle behaviors to protect against cognitive decline. Second, we present results from human studies demonstrating that CR might be beneficial for improving age-related cognitive decline and cognitive impairment in the clinical population such as obesity and type 2 diabetes. Third, the potential mechanisms regarding the protective effects of CR on cognition are discussed. Fourth, specific suggestions are highlighted to be considered in future human studies. Overall, although there are few data available from human studies, CR appears to be beneficial for cognitive protection for both healthy and clinical populations. Further scientific investigations are needed before a firm conclusion can be made.
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Affiliation(s)
- Qian Yu
- Exercise and Mental Health Laboratory, Shenzhen University, Shenzhen, China
| | - Liye Zou
- Exercise and Mental Health Laboratory, Shenzhen University, Shenzhen, China.
| | - Zhaowei Kong
- Faculty of Education, University of Macau, Macao, China
| | - Lin Yang
- Department of Cancer Epidemiology and Prevention Research, Alberta Health Services, Calgary, Canada; Departments of Oncology and Community Health Sciences, Cumming School of Medicine, University of Calgary, Calgary, Canada
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26
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Dias IR, Santos CDS, Magalhães CODE, de Oliveira LRS, Peixoto MFD, De Sousa RAL, Cassilhas RC. Does calorie restriction improve cognition? IBRO Rep 2020; 9:37-45. [PMID: 33336102 PMCID: PMC7733132 DOI: 10.1016/j.ibror.2020.05.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/26/2020] [Accepted: 05/29/2020] [Indexed: 01/14/2023] Open
Abstract
Calorie restriction (CR) has been considered the most effective non-pharmacological intervention to counteract aging-related diseases and improve longevity. This intervention has shown beneficial effects in the prevention and treatment of several chronic diseases and functional declines related to aging, such as Parkinson's, Alzheimer's, and neuroendocrine disorders. However, the effects of CR on cognition show controversial results since its effects vary according to intensity, duration, and the period of CR. This review focuses on the main studies published in the last ten years regarding the consequences of CR on cognition in different neurological diseases and conditions of experimental animals. Also, possible CR mimetics are discussed. These findings highlight the potential beneficial effects of CR of up to 40 % on cognition when started early in life in non human animals.
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Affiliation(s)
- Isabella Rocha Dias
- Neuroplasticity and Exercise Study Group (Grupo de Estudos em Neuroplasticidade e Exercício - GENE), UFVJM, Diamantina, MG, Brazil.,Multicenter Post Graduation Program in Physiological Sciences (PMPGCF), UFVJM, Brazilian Society of Physiology, Diamantina, MG, Brazil
| | - Carina de Sousa Santos
- Multicenter Post Graduation Program in Physiological Sciences (PMPGCF), UFVJM, Brazilian Society of Physiology, Diamantina, MG, Brazil
| | - Caíque Olegário Diniz E Magalhães
- Neuroplasticity and Exercise Study Group (Grupo de Estudos em Neuroplasticidade e Exercício - GENE), UFVJM, Diamantina, MG, Brazil.,Multicenter Post Graduation Program in Physiological Sciences (PMPGCF), UFVJM, Brazilian Society of Physiology, Diamantina, MG, Brazil
| | - Lucas Renan Sena de Oliveira
- Neuroplasticity and Exercise Study Group (Grupo de Estudos em Neuroplasticidade e Exercício - GENE), UFVJM, Diamantina, MG, Brazil.,Multicenter Post Graduation Program in Physiological Sciences (PMPGCF), UFVJM, Brazilian Society of Physiology, Diamantina, MG, Brazil
| | - Marco Fabrício Dias Peixoto
- Department of Physical Education, Federal University of the Valleys of Jequitinhonha and Mucuri (UFVJM), Diamantina, MG, Brazil.,Neuroplasticity and Exercise Study Group (Grupo de Estudos em Neuroplasticidade e Exercício - GENE), UFVJM, Diamantina, MG, Brazil.,Multicenter Post Graduation Program in Physiological Sciences (PMPGCF), UFVJM, Brazilian Society of Physiology, Diamantina, MG, Brazil.,Post Graduation Program in Health Science (PPGCS), UFVJM, Diamantina, MG, Brazil
| | - Ricardo Augusto Leoni De Sousa
- Neuroplasticity and Exercise Study Group (Grupo de Estudos em Neuroplasticidade e Exercício - GENE), UFVJM, Diamantina, MG, Brazil.,Multicenter Post Graduation Program in Physiological Sciences (PMPGCF), UFVJM, Brazilian Society of Physiology, Diamantina, MG, Brazil
| | - Ricardo Cardoso Cassilhas
- Department of Physical Education, Federal University of the Valleys of Jequitinhonha and Mucuri (UFVJM), Diamantina, MG, Brazil.,Neuroplasticity and Exercise Study Group (Grupo de Estudos em Neuroplasticidade e Exercício - GENE), UFVJM, Diamantina, MG, Brazil.,Multicenter Post Graduation Program in Physiological Sciences (PMPGCF), UFVJM, Brazilian Society of Physiology, Diamantina, MG, Brazil.,Post Graduation Program in Health Science (PPGCS), UFVJM, Diamantina, MG, Brazil
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Jeon SG, Hong SB, Nam Y, Tae J, Yoo A, Song EJ, Kim KI, Lee D, Park J, Lee SM, Kim JI, Moon M. Ghrelin in Alzheimer's disease: Pathologic roles and therapeutic implications. Ageing Res Rev 2019; 55:100945. [PMID: 31434007 DOI: 10.1016/j.arr.2019.100945] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2019] [Revised: 07/25/2019] [Accepted: 08/16/2019] [Indexed: 12/11/2022]
Abstract
Ghrelin, which has many important physiological roles, such as stimulating food intake, regulating energy homeostasis, and releasing insulin, has recently been studied for its roles in a diverse range of neurological disorders. Despite the several functions of ghrelin in the central nervous system, whether it works as a therapeutic agent for neurological dysfunction has been unclear. Altered levels and various roles of ghrelin have been reported in Alzheimer's disease (AD), which is characterized by the accumulation of misfolded proteins resulting in synaptic loss and cognitive decline. Interestingly, treatment with ghrelin or with the agonist of ghrelin receptor showed attenuation in several cases of AD-related pathology. These findings suggest the potential therapeutic implications of ghrelin in the pathogenesis of AD. In the present review, we summarized the roles of ghrelin in AD pathogenesis, amyloid beta (Aβ) homeostasis, tau hyperphosphorylation, neuroinflammation, mitochondrial deficit, synaptic dysfunction and cognitive impairment. The findings from this review suggest that ghrelin has a novel therapeutic potential for AD treatment. Thus, rigorously designed studies are needed to establish an effective AD-modifying strategy.
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28
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Gregosa A, Vinuesa Á, Todero MF, Pomilio C, Rossi SP, Bentivegna M, Presa J, Wenker S, Saravia F, Beauquis J. Periodic dietary restriction ameliorates amyloid pathology and cognitive impairment in PDAPP-J20 mice: Potential implication of glial autophagy. Neurobiol Dis 2019; 132:104542. [PMID: 31351172 DOI: 10.1016/j.nbd.2019.104542] [Citation(s) in RCA: 21] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2019] [Revised: 06/30/2019] [Accepted: 07/22/2019] [Indexed: 12/29/2022] Open
Abstract
Dietary restriction promotes cell regeneration and stress resistance in multiple models of human diseases. One of the conditions that could potentially benefit from this strategy is Alzheimer's disease, a chronic, progressive and prevalent neurodegenerative disease. Although there are no effective pharmacological treatments for this pathology, lifestyle interventions could play therapeutic roles. Our objectives were 1) to evaluate the effects of dietary restriction on cognition, hippocampal amyloid deposition, adult neurogenesis and glial reactivity and autophagy in a mouse model of familial Alzheimer's disease, and 2) to analyze the role of glial cells mediating the effects of nutrient restriction in an in vitro model. Therefore, we established a periodic dietary restriction protocol in adult female PDAPP-J20 transgenic mice for 6 weeks. We found that dietary restriction, not involving overall caloric restriction, attenuated cognitive deficits, amyloid pathology and microglial reactivity in transgenic mice when compared with ad libitum-fed transgenic animals. Also, transgenic mice showed an increase in the astroglial positive signal for LC3, an autophagy-associated protein. In parallel, hippocampal adult neurogenesis was decreased in transgenic mice whereas dietary-restricted transgenic mice showed a neurogenic status similar to controls. In vitro experiments showed that nutrient restriction decreased astroglial and, indirectly, microglial NFκB activation in response to amyloid β peptides. Furthermore, nutrient restriction was able to preserve astroglial autophagic flux and to decrease intracellular amyloid after exposure to amyloid β peptides. Our results suggest neuroprotective effects of nutrient restriction in Alzheimer's disease, with modulation of glial activation and autophagy being potentially involved pathways.
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Affiliation(s)
- Amal Gregosa
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina; Cátedra de Anatomía e Histología, Facultad de Farmacia y Bioquímica, Universidad de Buenos Aires, Argentina
| | - Ángeles Vinuesa
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - María Florencia Todero
- Laboratorio de Fisiología de los Procesos Inflamatorios, Instituto de Medicina Experimental (IMEX), CONICET, Academia Nacional de Medicina, Buenos Aires, Argentina
| | - Carlos Pomilio
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - Soledad P Rossi
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina; Cátedra de Bioquímica Humana, Facultad de Medicina, Universidad de Buenos Aires, Argentina
| | - Melisa Bentivegna
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - Jessica Presa
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - Shirley Wenker
- Fundación Instituto Leloir-IIBA, CONICET, Buenos Aires, Argentina
| | - Flavia Saravia
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina
| | - Juan Beauquis
- Instituto de Biología y Medicina Experimental, CONICET, Buenos Aires, Argentina; Departamento de Química Biológica, Facultad de Ciencias Exactas y Naturales, Universidad de Buenos Aires, Argentina.
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29
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Abstract
SIGNIFICANCE NAD+ and NADP+ are important cosubstrates in redox reactions and participate in regulatory networks operating in adjustment of metabolic pathways. Moreover, NAD+ is a cosubstrate in post-translational modification of proteins and is involved in DNA repair. NADPH is indispensable for reductive syntheses and the redox chemistry involved in attaining and maintaining correct protein conformation. Recent Advances: Within a couple of decades, a wealth of information has been gathered on NAD(H)+/NADP(H) redox imaging, regulatory role of redox potential in assembly of spatial protein structures, and the role of ADP-ribosylation of regulatory proteins affecting both gene expression and metabolism. All these have a bearing also on disease, healthy aging, and longevity. CRITICAL ISSUES Knowledge of the signal propagation pathways of NAD+-dependent post-translational modifications is still fragmentary for explaining the mechanism of cellular stress effects and nutritional state on these actions. Evaluation of the cosubstrate and regulator roles of NAD(H) and NADP(H) still suffers from some controversies in experimental data. FUTURE DIRECTIONS Activating or inhibiting interventions in NAD+-dependent protein modifications for medical purposes has shown promise, but restraining tumor growth by inhibiting DNA repair in tumors by means of interference in sirtuins is still in the early stage. The same is true for the use of this technology in improving health and healthy aging. New genetically encoded specific NAD and NADP probes are expected to modernize the research on redox biology.
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Affiliation(s)
- Ilmo E Hassinen
- Faculty of Biochemistry and Molecular Medicine, University of Oulu, Oulu, Finland
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30
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Rubovitch V, Pharayra A, Har-Even M, Dvir O, Mattson MP, Pick CG. Dietary Energy Restriction Ameliorates Cognitive Impairment in a Mouse Model of Traumatic Brain Injury. J Mol Neurosci 2019; 67:613-621. [PMID: 30734244 DOI: 10.1007/s12031-019-01271-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2018] [Accepted: 01/24/2019] [Indexed: 12/12/2022]
Abstract
Traumatic brain injury (TBI) is one of the most common causes of neurological damage in young people. It was previously reported that dietary restriction, by either intermittent fasting (IF) or daily caloric restriction (CR), could protect neurons against dysfunction and degeneration in animal models of stroke and Parkinson's disease. Recently, several studies have shown that the protein Sirtuin 1 (SIRT1) plays a significant role in the induced neuroprotection following dietary restriction. In the present study, we found a significant reduction of SIRT1 levels in the cortex and hippocampus in a mouse model of mild weight-drop closed head TBI. This reduction was prevented in mice maintained on IF (alternate day fasting) and CR initiated after the head trauma. Hippocampus-dependent learning and memory (measured using a novel object recognition test) was impaired 30 days post-injury in mice fed ad libitum, but not in mice in the IF and CR groups. These results suggest a clinical potential for IF and/or CR as an intervention to reduce brain damage and improve functional outcome in TBI patients.
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Affiliation(s)
- V Rubovitch
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.
| | - A Pharayra
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - M Har-Even
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - O Dvir
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel
| | - M P Mattson
- Laboratory of Neurosciences, National Institute on Aging Intramural Research Program, Baltimore, MD, USA
| | - C G Pick
- Department of Anatomy and Anthropology, Sackler School of Medicine, Tel-Aviv University, Tel-Aviv, Israel.,Sagol School of Neuroscience, Tel-Aviv University, 69978, Tel-Aviv, Israel.,The Dr. Miriam and Sheldon G. Adelson Chair and Center for the Biology of Addictive Diseases, Tel-Aviv University, 69978, Tel-Aviv, Israel
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31
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Dietary Restriction and Neuroinflammation: A Potential Mechanistic Link. Int J Mol Sci 2019; 20:ijms20030464. [PMID: 30678217 PMCID: PMC6386998 DOI: 10.3390/ijms20030464] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2019] [Accepted: 01/19/2019] [Indexed: 12/12/2022] Open
Abstract
Chronic neuroinflammation is a common feature of the aged brain, and its association with the major neurodegenerative changes involved in cognitive impairment and motor dysfunction is well established. One of the most potent antiaging interventions tested so far is dietary restriction (DR), which extends the lifespan in various organisms. Microglia and astrocytes are two major types of glial cells involved in the regulation of neuroinflammation. Accumulating evidence suggests that the age-related proinflammatory activation of astrocytes and microglia is attenuated under DR. However, the molecular mechanisms underlying DR-mediated regulation of neuroinflammation are not well understood. Here, we review the current understanding of the effects of DR on neuroinflammation and suggest an underlying mechanistic link between DR and neuroinflammation that may provide novel insights into the role of DR in aging and age-associated brain disorders.
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32
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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.
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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
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33
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Chen XY, Du YF, Chen L. Neuropeptides Exert Neuroprotective Effects in Alzheimer's Disease. Front Mol Neurosci 2019; 11:493. [PMID: 30687008 PMCID: PMC6336706 DOI: 10.3389/fnmol.2018.00493] [Citation(s) in RCA: 54] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2018] [Accepted: 12/21/2018] [Indexed: 01/03/2023] Open
Abstract
Alzheimer's disease (AD) is an age-related neurodegenerative disorder characterized by cognitive deficits and neuronal loss. Deposition of beta-amyloid peptide (Aβ) causes neurotoxicity through the formation of plaques in brains of Alzheimer's disease. Numerous studies have indicated that the neuropeptides including ghrelin, neurotensin, pituitary adenylate cyclase-activating polypeptide (PACAP), neuropeptide Y, substance P and orexin are closely related to the pathophysiology of Alzheimer's disease. The levels of neuropeptides and their receptors change in Alzheimer's disease. These neuropeptides exert neuroprotective roles mainly through preventing Aβ accumulation, increasing neuronal glucose transport, increasing the production of neurotrophins, inhibiting endoplasmic reticulum stress and autophagy, modulating potassium channel activity and hippocampal long-term potentiation. Therefore, the neuropeptides may function as potential drug targets in the prevention and cure of Alzheimer's disease.
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Affiliation(s)
- Xin-Yi Chen
- Department of Physiology and Pathophysiology, Qingdao University, Qingdao, China.,Department of Neurology, Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Yi-Feng Du
- Department of Neurology, Provincial Hospital Affiliated to Shandong University, Jinan, China
| | - Lei Chen
- Department of Physiology and Pathophysiology, Qingdao University, Qingdao, China
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34
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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.
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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
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MK-0677, a Ghrelin Agonist, Alleviates Amyloid Beta-Related Pathology in 5XFAD Mice, an Animal Model of Alzheimer's Disease. Int J Mol Sci 2018; 19:ijms19061800. [PMID: 29912176 PMCID: PMC6032329 DOI: 10.3390/ijms19061800] [Citation(s) in RCA: 24] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Revised: 05/31/2018] [Accepted: 06/06/2018] [Indexed: 12/11/2022] Open
Abstract
Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by cognitive deficits, neuroinflammation, and neuronal death. The primary pathogenic cause is believed to be the accumulation of pathogenic amyloid beta (Aβ) assemblies in the brain. Ghrelin, which is a peptide hormone predominantly secreted from the stomach, is an endogenous ligand for the growth hormone secretagogue-receptor type 1a (GHS-R1a). MK-0677 is a ghrelin agonist that potently stimulates the GHS-R1a ghrelin receptor. Interestingly, previous studies have shown that ghrelin improves cognitive impairments and attenuates neuronal death and neuroinflammation in several neurological disorders. However, it is unknown whether MK-0677 can affect Aβ accumulation or Aβ-mediated pathology in the brains of patients with AD. Therefore, we examined the effects of MK-0677 administration on AD-related pathology in 5XFAD mice, an Aβ-overexpressing transgenic mouse model of AD. MK-0677 was intraperitoneally administered to three-month-old 5XFAD mice. To visualize Aβ accumulation, neuroinflammation, and neurodegeneration, thioflavin-S staining and immunostaining with antibodies against Aβ (4G8), ionized calcium-binding adaptor molecule 1 (Iba-1), glial fibrillary acidic protein (GFAP), neuronal nuclear antigen (NeuN), and synaptophysin were conducted in the neocortex of 5XFAD and wild-type mice, and to evaluate changes of phosphorylated cyclic adenosine monophosphate (cAMP) response element binding protein (pCREB) levels, immunostaining with antibody against pCREB was performed in dentate gyrus of the hippocampus of 5XFAD and wild-type mice. The histological analyses indicated that MK-0677-treated 5XFAD mice showed reduced Aβ deposition, gliosis, and neuronal and synaptic loss in the deep cortical layers, and inhibited the decrement of pCREB levels in dentate gyrus of the hippocampus compared to vehicle-treated 5XFAD mice. Our results showed that activation of the ghrelin receptor with MK-0677 inhibited the Aβ burden, neuroinflammation, and neurodegeneration, which suggested that MK-0677 might have potential as a treatment of the early phase of AD.
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36
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Sang YM, Wang LJ, Mao HX, Lou XY, Zhu YJ. The association of short-term memory and cognitive impairment with ghrelin, leptin, and cortisol levels in non-diabetic and diabetic elderly individuals. Acta Diabetol 2018; 55:531-539. [PMID: 29492658 DOI: 10.1007/s00592-018-1111-5] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/18/2017] [Accepted: 01/29/2018] [Indexed: 01/02/2023]
Abstract
AIMS This study assessed short-term memory and biochemical indicators with the levels of ghrelin, leptin, and cortisol between cognitive impairment and normal older adults with or without diabetes. METHODS We enrolled 286 older adults (aged 65-85 years) with or without diabetes from the local community. Short-term memory was assessed using pictures of common objects; cognitive functioning was assessed using the Mini-Mental State Examination (MMSE) and the Montreal Cognitive Assessment (MoCA). The physiological indexes assessed were plasma levels of fasting ghrelin and leptin, ghrelin level at 2_h after breakfast, 24-h urinary cortisol value, body mass index, and plasma cortisol levels at 8:00 a.m., 4:00 p.m., and 12:00 p.m. RESULTS In both non-diabetic and diabetic subjects, short-term memory was significantly lower in the impaired cognition group (5.99 ± 2.90 in non-diabetic subjects and 4.71 ± 2.14 in diabetic subjects) than in the normal cognition group (8.14 ± 2.23 in non-diabetic subjects and 7.82 ± 3.37 in diabetic subjects). Baseline ghrelin level was significantly lower in the impaired cognition group (9.07 ± 1.13 ng/mL in non-diabetic subjects and 7.76 ± 1.34 ng/mL in diabetic subjects) than in the normal cognition group (10.94 ± 1.53 ng/mL in non-diabetic subjects and 9.93 ± 1.76 ng/mL in diabetic subjects); plasma cortisol levels at 8:00 a.m., 4:00 p.m., and 12:00 p.m. were significantly higher in the impaired cognition group than in the normal cognition group, while no significant difference was observed in plasma levels of fasting leptin between different groups. CONCLUSIONS Fasting plasma ghrelin and cortisol levels may be markers of cognitive decline and memory loss. It is possible that adjusting their levels may have a therapeutic effect, and this should be investigated in future studies.
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Affiliation(s)
- Yu Ming Sang
- Department of Endocrinology, Jinhua Central Hospital, Jinhua, Zhejiang province, China.
| | - Li Jun Wang
- Department of Psychology, Zhejiang Normal University, Jinhua, China
| | - Hong Xian Mao
- Department of Endocrinology, Jinhua Central Hospital, Jinhua, Zhejiang province, China
| | - Xue Yong Lou
- Department of Endocrinology, Jinhua Central Hospital, Jinhua, Zhejiang province, China
| | - Yi Jun Zhu
- The Central Laboratory, Jinhua Central Hospital, Jinhua, Zhejiang province, China
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37
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Dhurandhar EJ, Pavela G, Kaiser KA, Dutton GR, Fontaine KR, Kim D, Shikany JM, Allison DB, Lewis CE. Body Mass Index and Subjective Social Status: The Coronary Artery Risk Development in Young Adults Study. Obesity (Silver Spring) 2018; 26:426-431. [PMID: 29280341 PMCID: PMC5783753 DOI: 10.1002/oby.22047] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/11/2017] [Revised: 08/17/2017] [Accepted: 09/22/2017] [Indexed: 02/02/2023]
Abstract
OBJECTIVE Subjective social status (SSS), or perceived social status, may explain, in part, the relationship between socioeconomic status (SES) and obesity. The objective of this study was to test whether SSS mediates the relationship between two indicators of SES (income and education) and body mass index (BMI). METHODS A cross-sectional, structural equation path analysis was applied to the Coronary Artery Risk Development in Young Adults (CARDIA) study (n = 2,624). The analysis tested whether SSS (MacArthur scale), education, and income were associated with BMI at the year 20 examination (adjusting for sex, age, and race), and it was hypothesized that the associations of education and income with BMI would be at least partly mediated by SSS. RESULTS SSS had a significant direct effect on BMI (-0.21, P = 0.018). Education had a significant direct relationship with SSS (0.11, P < 0.001) and a small but significant indirect relationship with BMI through SSS (-0.02, P = 0.022). Although income did not have a significant direct relationship with BMI, it did have a significant indirect relationship through SSS (b = -0.05, P = 0.019). CONCLUSIONS Results are consistent with the hypothesized model in which SSS partially mediates the relationship between SES indicators and BMI.
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Affiliation(s)
- Emily J. Dhurandhar
- Department of Kinesiology and Sport Management, Texas Tech University, Lubbock, TX
| | - Gregory Pavela
- Department of Health Behavior, University of Alabama at Birmingham, Birmingham, AL
- Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham AL
| | - Kathryn A. Kaiser
- Department of Health Behavior, University of Alabama at Birmingham, Birmingham, AL
- Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham AL
| | - Gareth R. Dutton
- Division of Preventive Medicine, University of Alabama at Birmingham, Birmingham AL
| | - Kevin R. Fontaine
- Department of Health Behavior, University of Alabama at Birmingham, Birmingham, AL
- Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham AL
| | - Daniel Kim
- Department of Health Sciences, Bouve College of Health Sciences, Northeastern University, Boston, MA
| | - James M. Shikany
- Nutrition Obesity Research Center, University of Alabama at Birmingham, Birmingham AL
- Division of Preventive Medicine, University of Alabama at Birmingham, Birmingham AL
| | | | - Cora E. Lewis
- Division of Preventive Medicine, University of Alabama at Birmingham, Birmingham AL
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38
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Calorie restriction in rodents: Caveats to consider. Ageing Res Rev 2017; 39:15-28. [PMID: 28610949 DOI: 10.1016/j.arr.2017.05.008] [Citation(s) in RCA: 90] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2017] [Revised: 05/30/2017] [Accepted: 05/31/2017] [Indexed: 02/08/2023]
Abstract
The calorie restriction paradigm has provided one of the most widely used and most useful tools for investigating mechanisms of aging and longevity. By far, rodent models have been employed most often in these endeavors. Over decades of investigation, claims have been made that the paradigm produces the most robust demonstration that aging is malleable. In the current review of the rodent literature, we present arguments that question the robustness of the paradigm to increase lifespan and healthspan. Specifically, there are several questions to consider as follows: (1) At what age does CR no longer produce benefits? (2) Does CR attenuate cognitive decline? (3) Are there negative effects of CR, including effects on bone health, wound healing, and response to infection? (4) How important is schedule of feeding? (5) How long does CR need to be imposed to be effective? (6) How do genotype and gender influence CR? (7) What role does dietary composition play? Consideration of these questions produce many caveats that should guide future investigations to move the field forward.
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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.
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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
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40
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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.
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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.
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Ma L, Wang R, Dong W, Li Y, Xu B, Zhang J, Zhao Z. Long-term caloric restriction in mice may prevent age-related learning impairment via suppression of apoptosis. Behav Brain Res 2016; 315:45-50. [DOI: 10.1016/j.bbr.2016.07.036] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2016] [Revised: 07/15/2016] [Accepted: 07/20/2016] [Indexed: 11/29/2022]
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Mendiola-Precoma J, Berumen LC, Padilla K, Garcia-Alcocer G. Therapies for Prevention and Treatment of Alzheimer's Disease. BIOMED RESEARCH INTERNATIONAL 2016; 2016:2589276. [PMID: 27547756 PMCID: PMC4980501 DOI: 10.1155/2016/2589276] [Citation(s) in RCA: 137] [Impact Index Per Article: 17.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/23/2016] [Revised: 05/31/2016] [Accepted: 06/05/2016] [Indexed: 01/11/2023]
Abstract
Alzheimer's disease (AD) is the most common cause of dementia associated with a progressive neurodegenerative disorder, with a prevalence of 44 million people throughout the world in 2015, and this figure is estimated to double by 2050. This disease is characterized by blood-brain barrier disruption, oxidative stress, mitochondrial impairment, neuroinflammation, and hypometabolism; it is related to amyloid-β peptide accumulation and tau hyperphosphorylation as well as a decrease in acetylcholine levels and a reduction of cerebral blood flow. Obesity is a major risk factor for AD, because it induces adipokine dysregulation, which consists of the release of the proinflammatory adipokines and decreased anti-inflammatory adipokines, among other processes. The pharmacological treatments for AD can be divided into two categories: symptomatic treatments such as acetylcholinesterase inhibitors and N-methyl-D-aspartate (NMDA) receptor antagonists and etiology-based treatments such as secretase inhibitors, amyloid binders, and tau therapies. Strategies for prevention of AD through nonpharmacological treatments are associated with lifestyle interventions such as exercise, mental challenges, and socialization as well as caloric restriction and a healthy diet. AD is an important health issue on which all people should be informed so that prevention strategies that minimize the risk of its development may be implemented.
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Affiliation(s)
- J. Mendiola-Precoma
- Laboratorio de Investigación Genética, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas S/N, Centro Universitario, 76010 Santiago de Querétaro, QRO, Mexico
| | - L. C. Berumen
- Laboratorio de Investigación Genética, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas S/N, Centro Universitario, 76010 Santiago de Querétaro, QRO, Mexico
| | - K. Padilla
- Laboratorio de Investigación Genética, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas S/N, Centro Universitario, 76010 Santiago de Querétaro, QRO, Mexico
| | - G. Garcia-Alcocer
- Laboratorio de Investigación Genética, Facultad de Química, Universidad Autónoma de Querétaro, Cerro de las Campanas S/N, Centro Universitario, 76010 Santiago de Querétaro, QRO, Mexico
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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.
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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.
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44
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Dietary composition affects the development of cognitive deficits in WT and Tg AD model mice. Exp Gerontol 2016; 86:39-49. [PMID: 27167583 DOI: 10.1016/j.exger.2016.05.003] [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: 12/01/2015] [Revised: 04/22/2016] [Accepted: 05/06/2016] [Indexed: 01/17/2023]
Abstract
Clinical and epidemiological evidence suggests that lifestyle factors, including nutrition, may influence the chances of developing of Alzheimer's disease (AD), and also likely affect the aging process. Whereas it is clear that high-fat diets are increasing both body weight and the risk of developing Alzheimer's disease, to date, there have been very few studies comparing diets high with different sources of calories (i.e., high fat versus high protein versus high carbohydrates) to determine whether dietary composition has importance beyond the known effect of high caloric intake to increase body weight, AD pathology and cognitive deficits. In the current study we examined the effects that different diets high in carbohydrate, protein or fat content, but similar in caloric value, have on the development of cognitive impairment and brain pathology in wild-type and Tg AD model mice. The results demonstrate that long term feeding with balanced diets similar in caloric content but with significant changes in the source of calories, all negatively influence cognition compared to the control diet, and that this effect is more pronounced in Tg animals with AD pathology.
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45
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Bayliss JA, Lemus M, Santos VV, Deo M, Elsworth JD, Andrews ZB. Acylated but not des-acyl ghrelin is neuroprotective in an MPTP mouse model of Parkinson's disease. J Neurochem 2016; 137:460-71. [PMID: 26872221 PMCID: PMC4836972 DOI: 10.1111/jnc.13576] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2015] [Revised: 01/20/2016] [Accepted: 02/01/2016] [Indexed: 12/11/2022]
Abstract
The gut hormone ghrelin is widely beneficial in many disease states. However, ghrelin exists in two distinctive isoforms, each with its own metabolic profile. In Parkinson's Disease (PD) acylated ghrelin administration is neuroprotective, however, the role of des-acylated ghrelin remains unknown. In this study, we wanted to identify the relative contribution each isoform plays using the MPTP model of PD. Chronic administration of acylated ghrelin in mice lacking both isoforms of ghrelin (Ghrelin KO) attenuated the MPTP-induced loss on tyrosine hydroxylase (TH) neuronal number and volume and TH protein expression in the nigrostriatal pathway. Moreover, acylated ghrelin reduced the increase in glial fibrillary acidic protein and Ionized calcium binding adaptor molecule 1 microglia in the substantia nigra. However, injection of acylated ghrelin also elevated plasma des-acylated ghrelin, indicating in vivo deacetylation. Next, we chronically administered des-acylated ghrelin to Ghrelin KO mice and observed no neuroprotective effects in terms of TH cell number, TH protein expression, glial fibrillary acidic protein and ionized calcium binding adaptor molecule 1 cell number. The lack of a protective effect was mirrored in ghrelin-O-acyltransferase KO mice, which lack the ability to acylate ghrelin and consequently these mice have chronically increased plasma des-acyl ghrelin. Plasma corticosterone was elevated in ghrelin-O-acyltransferase KO mice and with des-acylated ghrelin administration. Overall, our studies suggest that acylated ghrelin is the isoform responsible for in vivo neuroprotection and that pharmacological approaches preventing plasma conversion from acyl ghrelin to des-acyl ghrelin may have clinical efficacy to help slow or prevent the debilitating effects of PD. Ghrelin exists in the plasma as acyl and des-acyl ghrelin. We determined the form responsible for in vivo neuroprotection in a mouse model of Parkinson's disease. Although exogenous acyl ghrelin is deacylated in situ to des-acyl, only acyl ghrelin was neuroprotective by attenuating dopamine cell loss and glial activation. Acyl ghrelin is a therapeutic option to reduce Parkinson's Disease progression. Cover Image for this issue: doi: 10.1111/jnc.13316.
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Affiliation(s)
- Jacqueline A Bayliss
- Department of Physiology, School of Biomedical and Psychological Sciences, Monash University, Melbourne, Vic., Australia
| | - Moyra Lemus
- Department of Physiology, School of Biomedical and Psychological Sciences, Monash University, Melbourne, Vic., Australia
| | - Vanessa V Santos
- Department of Physiology, School of Biomedical and Psychological Sciences, Monash University, Melbourne, Vic., Australia
| | - Minh Deo
- Department of Physiology, School of Biomedical and Psychological Sciences, Monash University, Melbourne, Vic., Australia
| | - John D Elsworth
- Department of Psychiatry, Yale University School of Medicine, New Haven, Connecticut, USA
| | - Zane B Andrews
- Department of Physiology, School of Biomedical and Psychological Sciences, Monash University, Melbourne, Vic., Australia
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46
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Ghrelin and Neurodegenerative Disorders-a Review. Mol Neurobiol 2016; 54:1144-1155. [PMID: 26809582 DOI: 10.1007/s12035-016-9729-1] [Citation(s) in RCA: 50] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/03/2015] [Accepted: 01/14/2016] [Indexed: 12/13/2022]
Abstract
Ghrelin, the endogenous ligand of the growth hormone secretagogue receptor 1a (GHS-R1a), is a gut-derived, orexigenic peptide hormone that primarily regulates growth hormone secretion, food intake, and energy homeostasis. With the wide expression of GHS-R1a in extra-hypothalamic regions, the physiological role of ghrelin is more extensive than solely its involvement in metabolic function. Ghrelin has been shown to be involved in numerous higher brain functions, such as memory, reward, mood, and sleep. Some of these functions are disrupted in neurodegenerative disorders, including Parkinson's disease (PD), Alzheimer's disease (AD), and Huntington's disease (HD). This link between ghrelin and these neurodegenerative diseases is supported by numerous studies. This review aims to provide a comprehensive overview of the most recent evidence of the novel neuromodulatory role of ghrelin in PD, AD, and HD. Moreover, the changes in circulating and/or central ghrelin levels that are associated with disease progression are also postulated to be a biomarker for clinical diagnosis and therapy.
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47
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Vasconcelos AR, Cabral-Costa JV, Mazucanti CH, Scavone C, Kawamoto EM. The Role of Steroid Hormones in the Modulation of Neuroinflammation by Dietary Interventions. Front Endocrinol (Lausanne) 2016; 7:9. [PMID: 26869995 PMCID: PMC4740355 DOI: 10.3389/fendo.2016.00009] [Citation(s) in RCA: 23] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/30/2015] [Accepted: 01/21/2016] [Indexed: 12/20/2022] Open
Abstract
Steroid hormones, such as sex hormones and glucocorticoids, have been demonstrated to play a role in different cellular processes in the central nervous system, ranging from neurodevelopment to neurodegeneration. Environmental factors, such as calorie intake or fasting frequency, may also impact on such processes, indicating the importance of external factors in the development and preservation of a healthy brain. The hypothalamic-pituitary-adrenal axis and glucocorticoid activity play a role in neurodegenerative processes, including in disorders such as in Alzheimer's and Parkinson's diseases. Sex hormones have also been shown to modulate cognitive functioning. Inflammation is a common feature in neurodegenerative disorders, and sex hormones/glucocorticoids can act to regulate inflammatory processes. Intermittent fasting can protect the brain against cognitive decline that is induced by an inflammatory stimulus. On the other hand, obesity increases susceptibility to inflammation, while metabolic syndromes, such as diabetes, are associated with neurodegeneration. Consequently, given that gonadal and/or adrenal steroids may significantly impact the pathophysiology of neurodegeneration, via their effect on inflammatory processes, this review focuses on how environmental factors, such as calorie intake and intermittent fasting, acting through their modulation of steroid hormones, impact on inflammation that contributes to cognitive and neurodegenerative processes.
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Affiliation(s)
- Andrea Rodrigues Vasconcelos
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - João Victor Cabral-Costa
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Caio Henrique Mazucanti
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Cristoforo Scavone
- Laboratory of Molecular Neuropharmacology, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
| | - Elisa Mitiko Kawamoto
- Laboratory of Molecular and Functional Neurobiology, Department of Pharmacology, Institute of Biomedical Science, University of São Paulo, São Paulo, Brazil
- *Correspondence: Elisa Mitiko Kawamoto,
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48
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Ben-Soussan TD, Glicksohn J, Berkovich-Ohana A. From Cerebellar Activation and Connectivity to Cognition: A Review of the Quadrato Motor Training. BIOMED RESEARCH INTERNATIONAL 2015; 2015:954901. [PMID: 26539545 PMCID: PMC4619922 DOI: 10.1155/2015/954901] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/13/2015] [Accepted: 05/06/2015] [Indexed: 11/18/2022]
Abstract
The importance of the cerebellum is increasingly recognized, not only in motor control but also in cognitive learning and function. Nevertheless, the relationship between training-induced cerebellar activation and electrophysiological and structural changes in humans has yet to be established. In the current paper, we suggest a general model tying cerebellar function to cognitive improvement, via neuronal synchronization, as well as biochemical and anatomical changes. We then suggest that sensorimotor training provides an optimal paradigm to test the proposed model and review supporting evidence of Quadrato Motor Training (QMT), a sensorimotor training aimed at increasing attention and coordination. Subsequently, we discuss the possible mechanisms through which QMT may exert its beneficial effects on cognition (e.g., increased creativity, reflectivity, and reading), focusing on cerebellar alpha activity as a possible mediating mechanism allowing cognitive improvement, molecular and anatomical changes. Using the example of QMT research, this paper emphasizes the importance of investigating whole-body sensorimotor training paradigms utilizing a multidisciplinary approach and its implications to healthy brain development.
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Affiliation(s)
- Tal Dotan Ben-Soussan
- The Leslie and Susan Gonda (Goldschmied) Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
- Research Institute for Neuroscience, Education and Didactics, Patrizio Paoletti Foundation, Rome, Italy
| | - Joseph Glicksohn
- The Leslie and Susan Gonda (Goldschmied) Multidisciplinary Brain Research Center, Bar-Ilan University, Ramat Gan, Israel
- Department of Criminology, Bar-Ilan University, Ramat Gan, Israel
| | - Aviva Berkovich-Ohana
- Department of Neurobiology, Weizmann Institute of Science, Rehovot, Israel
- Department of Physiology and Pharmacology, University of Rome “La Sapienza”, Rome, Italy
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49
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Kunath N, van Groen T, Allison DB, Kumar A, Dozier-Sharpe M, Kadish I. Ghrelin agonist does not foster insulin resistance but improves cognition in an Alzheimer's disease mouse model. Sci Rep 2015; 5:11452. [PMID: 26090621 PMCID: PMC4473679 DOI: 10.1038/srep11452] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2015] [Accepted: 05/15/2015] [Indexed: 12/24/2022] Open
Abstract
The orexigenic hormone ghrelin, a potential antagonist of the insulin system, ensures sufficient serum glucose in times of fasting. In the race for new therapeutics for diabetes, one focus of study has been antagonizing the ghrelin system in order to improve glucose tolerance. We provide evidence for a differential role of a ghrelin agonist on glucose homeostasis in an Alzheimer’s disease mouse model fed a high–glycemic index diet as a constant challenge for glucose homeostasis. The ghrelin agonist impaired glucose tolerance immediately after administration but not in the long term. At the same time, the ghrelin agonist improved spatial learning in the mice, raised their activity levels, and reduced their body weight and fat mass. Immunoassay results showed a beneficial impact of long-term treatment on insulin signaling pathways in hippocampal tissue. The present results suggest that ghrelin might improve cognition in Alzheimer’s disease via a central nervous system mechanism involving insulin signaling.
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Affiliation(s)
- Nicolas Kunath
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham AL, USA.,Department of Clinical Research, Max-Planck-Institute of Psychiatry, Munich, Germany
| | - Thomas van Groen
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham AL, USA
| | - David B Allison
- Office of Energetics; Nutrition Obesity Research Center; Department of Nutrition Sciences, University of Alabama at Birmingham, Birmingham, AL, USA
| | - Ashish Kumar
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham AL, USA
| | - Monique Dozier-Sharpe
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham AL, USA
| | - Inga Kadish
- Department of Cell, Developmental and Integrative Biology, University of Alabama at Birmingham, Birmingham AL, USA
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50
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Wittekind DA, Kluge M. Ghrelin in psychiatric disorders - A review. Psychoneuroendocrinology 2015; 52:176-94. [PMID: 25459900 DOI: 10.1016/j.psyneuen.2014.11.013] [Citation(s) in RCA: 69] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/29/2014] [Revised: 11/13/2014] [Accepted: 11/13/2014] [Indexed: 12/21/2022]
Abstract
Ghrelin is a 28-amino-acid peptide hormone, first described in 1999 and broadly expressed in the organism. As the only known orexigenic hormone secreted in the periphery, it increases hunger and appetite, promoting food intake. Ghrelin has also been shown to be involved in various physiological processes being regulated in the central nervous system such as sleep, mood, memory and reward. Accordingly, it has been implicated in a series of psychiatric disorders, making it subject of increasing investigation, with knowledge rapidly accumulating. This review aims at providing a concise yet comprehensive overview of the role of ghrelin in psychiatric disorders. Ghrelin was consistently shown to exert neuroprotective and memory-enhancing effects and alleviated psychopathology in animal models of dementia. Few human studies show a disruption of the ghrelin system in dementia. It was also shown to play a crucial role in the pathophysiology of addictive disorders, promoting drug reward, enhancing drug seeking behavior and increasing craving in both animals and humans. Ghrelin's exact role in depression and anxiety is still being debated, as it was shown to both promote and alleviate depressive and anxiety-behavior in animal studies, with an overweight of evidence suggesting antidepressant effects. Not surprisingly, the ghrelin system is also implicated in eating disorders, however its exact role remains to be elucidated. Its widespread involvement has made the ghrelin system a promising target for future therapies, with encouraging findings in recent literature.
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Affiliation(s)
| | - Michael Kluge
- Department of Psychiatry and Psychotherapy, University of Leipzig, Leipzig, Germany
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