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Gendron WH, Fertan E, Roddick KM, Wong AA, Maliougina M, Hiani YE, Anini Y, Brown RE. Intranasal insulin treatment ameliorates spatial memory, muscular strength, and frailty deficits in 5xFAD mice. Physiol Behav 2024; 281:114583. [PMID: 38750806 DOI: 10.1016/j.physbeh.2024.114583] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/29/2023] [Revised: 05/11/2024] [Accepted: 05/13/2024] [Indexed: 05/19/2024]
Abstract
The 5xFAD mouse model shows age-related weight loss as well as cognitive and motor deficits. Metabolic dysregulation, especially impaired insulin signaling, is also present in AD. This study examined whether intranasal delivery of insulin (INI) at low (0.875 U) or high (1.750 U) doses would ameliorate these deficits compared to saline in 10-month-old female 5xFAD and B6SJL wildtype (WT) mice. INI increased forelimb grip strength in the wire hang test in 5xFAD mice in a dose-dependent manner but did not improve the performance of 5xFAD mice on the balance beam. High INI doses reduced frailty scores in 5xFAD mice and improved spatial memory in both acquisition and reversal probe trials in the Morris water maze. INI increased swim speed in 5xFAD mice but had no effect on object recognition memory or working memory in the spontaneous alternation task, nor did it improve memory in the contextual or cued fear memory tasks. High doses of insulin increased the liver, spleen, and kidney weights and reduced brown adipose tissue weights. P-Akt signaling in the hippocampus was increased by insulin in a dose-dependent manner. Altogether, INI increased strength, reduced frailty scores, and improved visual spatial memory. Hypoglycemia was not present after INI, however alterations in tissue and organ weights were present. These results are novel and important as they indicate that intra-nasal insulin can reverse cognitive, motor and frailty deficits found in this mouse model of AD.
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Affiliation(s)
- William H Gendron
- Departments of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Emre Fertan
- Departments of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Kyle M Roddick
- Departments of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Aimée A Wong
- Departments of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Maria Maliougina
- Departments of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Yassine El Hiani
- Departments of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Younes Anini
- Departments of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Departments of Obstetrics and Gynecology, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada
| | - Richard E Brown
- Departments of Psychology and Neuroscience, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada; Departments of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia B3H 4R2, Canada.
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Martinez-Feduchi P, Jin P, Yao B. Epigenetic modifications of DNA and RNA in Alzheimer's disease. Front Mol Neurosci 2024; 17:1398026. [PMID: 38726308 PMCID: PMC11079283 DOI: 10.3389/fnmol.2024.1398026] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2024] [Accepted: 04/15/2024] [Indexed: 05/12/2024] Open
Abstract
Alzheimer's disease (AD) is a complex neurodegenerative disorder and the most common form of dementia. There are two main types of AD: familial and sporadic. Familial AD is linked to mutations in amyloid precursor protein (APP), presenilin-1 (PSEN1), and presenilin-2 (PSEN2). On the other hand, sporadic AD is the more common form of the disease and has genetic, epigenetic, and environmental components that influence disease onset and progression. Investigating the epigenetic mechanisms associated with AD is essential for increasing understanding of pathology and identifying biomarkers for diagnosis and treatment. Chemical covalent modifications on DNA and RNA can epigenetically regulate gene expression at transcriptional and post-transcriptional levels and play protective or pathological roles in AD and other neurodegenerative diseases.
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Affiliation(s)
| | | | - Bing Yao
- Department of Human Genetics, Emory University School of Medicine, Atlanta, GA, United States
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Xing X, Sun Q, Wang R, Wang Y, Wang R. Impacts of glutamate, an exercise-responsive metabolite on insulin signaling. Life Sci 2024; 341:122471. [PMID: 38301875 DOI: 10.1016/j.lfs.2024.122471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/28/2023] [Revised: 01/24/2024] [Accepted: 01/25/2024] [Indexed: 02/03/2024]
Abstract
AIMS Disruption of the insulin signaling pathway leads to insulin resistance (IR). IR is characterized by impaired glucose and lipid metabolism. Elevated levels of circulating glutamate are correlated with metabolic indicators and may potentially predict the onset of metabolic diseases. Glutamate receptor antagonists have significantly enhanced insulin sensitivity, and improved glucose and lipid metabolism. Exercise is a well-known strategy to combat IR. The aims of our narrative review are to summarize preclinical and clinical findings to show the correlations between circulating glutamate levels, IR and metabolic diseases, discuss the causal role of excessive glutamate in IR and metabolic disturbance, and present an overview of the exercise-induced alteration in circulating glutamate levels. MATERIALS AND METHODS A literature search was conducted to identify studies on glutamate, insulin signaling, and exercise in the PubMed database. The search covered articles published from December 1955 to January 2024, using the search terms of "glutamate", "glutamic acid", "insulin signaling", "insulin resistance", "insulin sensitivity", "exercise", and "physical activity". KEY FINDINGS Elevated levels of circulating glutamate are correlated with IR. Excessive glutamate can potentially hinder the insulin signaling pathway through various mechanisms, including the activation of ectopic lipid accumulation, inflammation, and endoplasmic reticulum stress. Glutamate can also modify mitochondrial function through Ca2+ and induce purine degradation mediated by AMP deaminase 2. Exercise has the potential to decrease circulating levels of glutamate, which can be attributed to accelerated glutamate catabolism and enhanced glutamate uptake. SIGNIFICANCE Glutamate may act as a mediator in the exercise-induced improvement of insulin sensitivity.
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Affiliation(s)
- Xiaorui Xing
- School of Exercise and Health, Shanghai University of Sport, Shanghai 200438, China
| | - Qin Sun
- School of Exercise and Health, Shanghai University of Sport, Shanghai 200438, China
| | - Ruwen Wang
- School of Exercise and Health, Shanghai University of Sport, Shanghai 200438, China
| | - Yibing Wang
- School of Exercise and Health, Shanghai University of Sport, Shanghai 200438, China.
| | - Ru Wang
- School of Exercise and Health, Shanghai University of Sport, Shanghai 200438, China.
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Baranovicova E, Kalenska D, Kaplan P, Kovalska M, Tatarkova Z, Lehotsky J. Blood and Brain Metabolites after Cerebral Ischemia. Int J Mol Sci 2023; 24:17302. [PMID: 38139131 PMCID: PMC10743907 DOI: 10.3390/ijms242417302] [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] [Received: 10/27/2023] [Revised: 12/01/2023] [Accepted: 12/06/2023] [Indexed: 12/24/2023] Open
Abstract
The study of an organism's response to cerebral ischemia at different levels is essential to understanding the mechanism of the injury and protection. A great interest is devoted to finding the links between quantitative metabolic changes and post-ischemic damage. This work aims to summarize the outcomes of the most studied metabolites in brain tissue-lactate, glutamine, GABA (4-aminobutyric acid), glutamate, and NAA (N-acetyl aspartate)-regarding their biological function in physiological conditions and their role after cerebral ischemia/reperfusion. We focused on ischemic damage and post-ischemic recovery in both experimental-including our results-as well as clinical studies. We discuss the role of blood glucose in view of the diverse impact of hyperglycemia, whether experimentally induced, caused by insulin resistance, or developed as a stress response to the cerebral ischemic event. Additionally, based on our and other studies, we analyze and critically discuss post-ischemic alterations in energy metabolites and the elevation of blood ketone bodies observed in the studies on rodents. To complete the schema, we discuss alterations in blood plasma circulating amino acids after cerebral ischemia. So far, no fundamental brain or blood metabolite(s) has been recognized as a relevant biological marker with the feasibility to determine the post-ischemic outcome or extent of ischemic damage. However, studies from our group on rats subjected to protective ischemic preconditioning showed that these animals did not develop post-ischemic hyperglycemia and manifested a decreased metabolic infringement and faster metabolomic recovery. The metabolomic approach is an additional tool for understanding damaging and/or restorative processes within the affected brain region reflected in the blood to uncover the response of the whole organism via interorgan metabolic communications to the stressful cerebral ischemic challenge.
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Affiliation(s)
- Eva Baranovicova
- Biomedical Center BioMed, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia;
| | - Dagmar Kalenska
- Department of Anatomy, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia
| | - Peter Kaplan
- Department of Medical Biochemistry, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia (Z.T.)
| | - Maria Kovalska
- Department of Histology and Embryology, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia
| | - Zuzana Tatarkova
- Department of Medical Biochemistry, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia (Z.T.)
| | - Jan Lehotsky
- Department of Medical Biochemistry, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia (Z.T.)
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de Baat A, Meier DT, Rachid L, Fontana A, Böni-Schnetzler M, Donath MY. Cystine/glutamate antiporter System x c- deficiency impairs insulin secretion in mice. Diabetologia 2023; 66:2062-2074. [PMID: 37650924 PMCID: PMC10541846 DOI: 10.1007/s00125-023-05993-6] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/09/2023] [Accepted: 06/16/2023] [Indexed: 09/01/2023]
Abstract
AIMS/HYPOTHESIS Glutamate-induced cytotoxicity (excitotoxicity) has been detected in pancreatic beta cells. The cystine/glutamate antiporter System xc- exports glutamate to the extracellular space and is therefore implicated as driving excitotoxicity. As of yet, it has not been investigated whether System xc- contributes to pancreatic islet function. METHODS This study describes the implications of deficiency of System xc- on glucose metabolism in both constitutive and myeloid cell-specific knockout mice using metabolic tests and diet-induced obesity. Pancreatic islets were isolated and analysed for beta cell function, glutathione levels and ER stress. RESULTS Constitutive System xc- deficiency led to an approximately threefold decrease in glutathione levels in the pancreatic islets as well as cystine shortage characterised by upregulation of Chac1. This shortage further manifested as downregulation of beta cell identity genes and a tonic increase in endoplasmic reticulum stress markers, which resulted in diminished insulin secretion both in vitro and in vivo. Myeloid-specific deletion did not have a significant impact on metabolism or islet function. CONCLUSIONS/INTERPRETATION These findings suggest that System xc- is required for glutathione maintenance and insulin production in beta cells and that the system is dispensable for islet macrophage function.
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Affiliation(s)
- Axel de Baat
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland.
- Department of Biomedicine, University of Basel, Basel, Switzerland.
| | - Daniel T Meier
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Leila Rachid
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Adriano Fontana
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Marianne Böni-Schnetzler
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland
- Department of Biomedicine, University of Basel, Basel, Switzerland
| | - Marc Y Donath
- Clinic of Endocrinology, Diabetes and Metabolism, University Hospital Basel, Basel, Switzerland
- Department of Biomedicine, University of Basel, Basel, Switzerland
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Soleymani T, Chen TY, Gonzalez-Kozlova E, Dogra N. The human neurosecretome: extracellular vesicles and particles (EVPs) of the brain for intercellular communication, therapy, and liquid-biopsy applications. Front Mol Biosci 2023; 10:1156821. [PMID: 37266331 PMCID: PMC10229797 DOI: 10.3389/fmolb.2023.1156821] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2023] [Accepted: 04/25/2023] [Indexed: 06/03/2023] Open
Abstract
Emerging evidence suggests that brain derived extracellular vesicles (EVs) and particles (EPs) can cross blood-brain barrier and mediate communication among neurons, astrocytes, microglial, and other cells of the central nervous system (CNS). Yet, a complete understanding of the molecular landscape and function of circulating EVs & EPs (EVPs) remain a major gap in knowledge. This is mainly due to the lack of technologies to isolate and separate all EVPs of heterogeneous dimensions and low buoyant density. In this review, we aim to provide a comprehensive understanding of the neurosecretome, including the extracellular vesicles that carry the molecular signature of the brain in both its microenvironment and the systemic circulation. We discuss the biogenesis of EVPs, their function, cell-to-cell communication, past and emerging isolation technologies, therapeutics, and liquid-biopsy applications. It is important to highlight that the landscape of EVPs is in a constant state of evolution; hence, we not only discuss the past literature and current landscape of the EVPs, but we also speculate as to how novel EVPs may contribute to the etiology of addiction, depression, psychiatric, neurodegenerative diseases, and aid in the real time monitoring of the "living brain". Overall, the neurosecretome is a concept we introduce here to embody the compendium of circulating particles of the brain for their function and disease pathogenesis. Finally, for the purpose of inclusion of all extracellular particles, we have used the term EVPs as defined by the International Society of Extracellular Vesicles (ISEV).
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Affiliation(s)
- Taliah Soleymani
- Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Tzu-Yi Chen
- Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Edgar Gonzalez-Kozlova
- Oncological Sciences, Icahn School of Medicine at Mount Sinai, New York, NY, United States
| | - Navneet Dogra
- Pathology, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Genetics and Genomics, Icahn School of Medicine at Mount Sinai, New York, NY, United States
- Icahn Genomics Institute, Icahn School of Medicine at Mount Sinai, New York, NY, United States
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An Early and Sustained Inflammatory State Induces Muscle Changes and Establishes Obesogenic Characteristics in Wistar Rats Exposed to the MSG-Induced Obesity Model. Int J Mol Sci 2023; 24:ijms24054730. [PMID: 36902158 PMCID: PMC10003260 DOI: 10.3390/ijms24054730] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2022] [Revised: 12/23/2022] [Accepted: 12/26/2022] [Indexed: 03/05/2023] Open
Abstract
The model of obesity induced by monosodium glutamate cytotoxicity on the hypothalamic nuclei is widely used in the literature. However, MSG promotes persistent muscle changes and there is a significant lack of studies that seek to elucidate the mechanisms by which damage refractory to reversal is established. This study aimed to investigate the early and chronic effects of MSG induction of obesity upon systemic and muscular parameters of Wistar rats. The animals were exposed to MSG subcutaneously (4 mg·g-1 b.w.) or saline (1.25 mg·g-1 b.w.) daily from PND01 to PND05 (n = 24). Afterwards, in PND15, 12 animals were euthanized to determine the plasma and inflammatory profile and to assess muscle damage. In PND142, the remaining animals were euthanized, and samples for histological and biochemical analyses were obtained. Our results suggest that early exposure to MSG reduced growth, increased adiposity, and inducted hyperinsulinemia and a pro-inflammatory scenario. In adulthood, the following were observed: peripheral insulin resistance, increased fibrosis, oxidative distress, and a reduction in muscle mass, oxidative capacity, and neuromuscular junctions, increased fibrosis, and oxidative distress. Thus, we can conclude that the condition found in adult life and the difficulty restoring in the muscle profile is related to the metabolic damage established early on.
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Kubis-Kubiak A, Wiatrak B, Piwowar A. Hyper-glycemia and insulinemia induce morphological changes and modulate secretion of S100B, S100A8, amyloid β 1–40 and amyloid β 1–42, in a model of human dopaminergic neurons. Biomed Pharmacother 2022; 156:113869. [DOI: 10.1016/j.biopha.2022.113869] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/16/2022] [Revised: 10/10/2022] [Accepted: 10/13/2022] [Indexed: 11/02/2022] Open
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Prognostic Significance of Plasma Insulin Level for Deep Venous Thrombosis in Patients with Severe Traumatic Brain Injury in Critical Care. Neurocrit Care 2022; 38:263-278. [PMID: 36114315 DOI: 10.1007/s12028-022-01588-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/25/2022] [Accepted: 08/10/2022] [Indexed: 10/14/2022]
Abstract
BACKGROUND Whether insulin resistance underlies deep venous thrombosis (DVT) development in patients with severe traumatic brain injury (TBI) is unclear. In this study, the association between plasma insulin levels and DVT was analyzed in patients with severe TBI. METHODS A prospective observational study of 73 patients measured insulin, glucose, glucagon-like peptide 1 (GLP-1), inflammatory factors, and hematological profiles within four preset times during the first 14 days after TBI. Ultrasonic surveillance of DVT was tracked. Two-way analysis of variance was used to determine the factors that discriminated between patients with and without DVT or with and without insulin therapy. Partial correlations of insulin level with all the variables were conducted separately in patients with DVT or patients without DVT. Factors associated with DVT were analyzed by multivariable logistic regression. Neurological outcomes 6 months after TBI were assessed. RESULTS Among patients with a mean (± standard deviation) age of 53 (± 16 years), DVT developed in 20 patients (27%) on median 10.4 days (range 4-22), with higher Acute Physiology and Chronic Health Evaluation II scores but similar Sequential Organ Failure Assessment scores and TBI severity. Patients with DVT were more likely to receive insulin therapy than patients without DVT (60% vs. 28%; P = 0.012); hence, they had higher 14-day insulin levels. However, insulin levels were comparable between patients with DVT and patients without DVT in the subgroups of patients with insulin therapy (n = 27) and patients without insulin therapy (n = 46). The platelet profile significantly discriminated between patients with and without DVT. Surprisingly, none of the coagulation profiles, blood cell counts, or inflammatory mediators differed between the two groups. Patients with insulin therapy had significantly higher insulin (P = 0.006), glucose (P < 0.001), and GLP-1 (P = 0.01) levels and were more likely to develop DVT (60% vs. 15%; P < 0.001) along with concomitant platelet depletion. Insulin levels correlated with glucose, GLP-1 levels, and platelet count exclusively in patients without DVT. Conversely, in patients with DVT, insulin correlated negatively with GLP-1 levels (P = 0.016). Age (P = 0.01) and elevated insulin levels at days 4-7 (P = 0.04) were independently associated with DVT. Patients with insulin therapy also showed worse Glasgow Outcome Scale scores (P = 0.001). CONCLUSIONS Elevated insulin levels in the first 14 days after TBI may indicate insulin resistance, which is associated with platelet hyperactivity, and thus increasing the risk of DVT.
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Baranovicova E, Kalenska D, Kovalska M, Lehotsky J. Hippocampal metabolic recovery as a manifestation of the protective effect of ischemic preconditioning in rats. Neurochem Int 2022; 160:105419. [PMID: 36113578 DOI: 10.1016/j.neuint.2022.105419] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2022] [Revised: 08/25/2022] [Accepted: 09/04/2022] [Indexed: 10/31/2022]
Abstract
The ever-present risk of brain ischemic events in humans and its full prevention make the detailed studies of an organism's response to ischemia at different levels essential to understanding the mechanism of the injury as well as protection. We used the four-vessel occlusion as an animal model of forebrain ischemia to investigate its impact on the metabolic alterations in both the hippocampus and the blood plasma to see changes on the systemic level. By inducing sublethal ischemic stimuli, we focused on the endogenous phenomena known as ischemic tolerance. NMR spectroscopy was used to analyze relative metabolite levels in tissue extracts from rats' hippocampus and blood plasma in three various ischemic/reperfusion times: 3 h, 24 h, and 72 h. Hippocampal tissues were characterized by postischemically decreased glutamate and GABA (4-aminobutyrate) tissue content balanced with increased glutamine level, with most pronounced changes at 3 h reperfusion time. Glutamate (as well as glutamine) levels recovered towards the control levels on the third day, as if the glutamate re-synthesis would be firstly preferred before GABA. These results are indicating the higher feasibility of re-establishing of glutamatergic transmission three days after an ischemic event, in contrast to GABA-ergic. Tissue levels of N-acetylaspartate (NAA), as well as choline, were decreased without the tendency to recover three days after the ischemic event. Metabolomic analysis of blood plasma revealed that ischemically preconditioned rats, contrary to the non-preconditioned animals, did not show hyperglycemic conditions. Ischemically induced semi-ketotic state, manifested in increased plasma ketone bodies 3-hydroxybutyrate and acetoacetate, seems to be programmed to support the brain tissue revitalization after the ischemic event. These and other metabolites changes found in blood plasma as well as in the hippocampus were observed to a lower extent or recovered faster in preconditioned animals. Some metabolomic changes in hippocampal tissue extract were so strong that even single metabolites were able to differentiate between ischemic, ischemically preconditioned, and control brain tissues.
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Affiliation(s)
- Eva Baranovicova
- Biomedical Center BioMed, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01, Martin, Slovakia
| | - Dagmar Kalenska
- Department of Anatomy, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01, Martin, Slovakia
| | - Maria Kovalska
- Department of Histology and Embryology, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01, Martin, Slovakia
| | - Jan Lehotsky
- Department of Medical Biochemistry, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01, Martin, Slovakia.
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Cao C, Wang H, Gao H, Wu W. Insulin resistance is associated with an unfavorable outcome among non-diabetic patients with isolated moderate-to-severe traumatic brain injury – A propensity score-matched study. Front Neurol 2022; 13:949091. [PMID: 35968315 PMCID: PMC9366396 DOI: 10.3389/fneur.2022.949091] [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] [Received: 05/20/2022] [Accepted: 07/04/2022] [Indexed: 12/27/2022] Open
Abstract
BackgroundHyperglycemia is an independent risk factor for the poor prognosis in patients with traumatic brain injury (TBI), and stress-induced impaired insulin function is the major factor of hyperglycemia in non-diabetic patients with TBI. Several types of research suggested that insulin resistance (IR) is related to the poor prognosis of neurocritical ill patients; here we focused on the role of IR in non-diabetic patients after TBI.MethodsWe performed a prospective observational study with the approval of the Ethics Committee of our institute. IR was accessed via the update Homeostasis Model Assessment (HOMA2) of IR, a computer-calculated index by glucose and insulin level. HOMA2 ≥ 1.4 was considered as the threshold of IR according to the previous studies. The glycemic variability (GV) indices were calculated by fingertip blood glucose concentration at an interval of 2 h within 24 h to explore the relationship between IR and GV. The outcome was the 6-month neurological outcome evaluated with the Glasgow outcome scale.ResultsA total of 85 patients with isolated moderate-to-severe TBI (admission GCS ≤ 12) were finally included in our study, 34 (40%) were diagnosed with IR with HOMA2 ≥ 1.4. After propensity score matching (PSM), 22 patients in IR group were matched to 34 patients in non-IR group. Patients with IR suffered increased systemic glycemic variation after isolated moderate-to-severe TBI. IR was a significant factor for the poor prognosis after TBI (OR = 3.25, 95% CI 1.03–10.31, p = 0.041).ConclusionsThe IR estimated by HOMA2 was associated with greater GV and an unfavorable outcome after isolated moderate-to-severe TBI. Ameliorating impaired insulin sensitivity may be a potential therapeutic strategy for the management of TBI patients.
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Shen Z, Xiang M, Chen C, Ding F, Wang Y, Shang C, Xin L, Zhang Y, Cui X. Glutamate excitotoxicity: Potential therapeutic target for ischemic stroke. Biomed Pharmacother 2022; 151:113125. [PMID: 35609367 DOI: 10.1016/j.biopha.2022.113125] [Citation(s) in RCA: 50] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2022] [Revised: 05/01/2022] [Accepted: 05/13/2022] [Indexed: 11/29/2022] Open
Abstract
Glutamate-mediated excitotoxicity is an important mechanism leading to post ischemic stroke damage. After acute stroke, the sudden reduction in cerebral blood flow is most initially followed by ion transport protein dysfunction and disruption of ion homeostasis, which in turn leads to impaired glutamate release, reuptake, and excessive N-methyl-D-aspartate receptor (NMDAR) activation, promoting neuronal death. Despite extensive evidence from preclinical studies suggesting that excessive NMDAR stimulation during ischemic stroke is a central step in post-stroke damage, NMDAR blockers have failed to translate into clinical stroke treatment. Current treatment options for stroke are very limited, and there is therefore a great need to develop new targets for neuroprotective therapeutic agents in ischemic stroke to extend the therapeutic time window. In this review, we highlight recent findings on glutamate release, reuptake mechanisms, NMDAR and its downstream cellular signaling pathways in post-ischemic stroke damage, and review the pathological changes in each link to help develop viable new therapeutic targets. We then also summarize potential neuroprotective drugs and therapeutic approaches for these new targets in the treatment of ischemic stroke.
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Affiliation(s)
- Zihuan Shen
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China; Clinical Medical School, Beijing University of Traditional Chinese Medicine, Beijing 100029, China
| | - Mi Xiang
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Chen Chen
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Fan Ding
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China; Clinical Medical School, Beijing University of Traditional Chinese Medicine, Beijing 100029, China
| | - Yuling Wang
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China; Clinical Medical School, Beijing University of Traditional Chinese Medicine, Beijing 100029, China
| | - Chang Shang
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China; Clinical Medical School, Beijing University of Traditional Chinese Medicine, Beijing 100029, China
| | - Laiyun Xin
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China
| | - Yang Zhang
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China.
| | - Xiangning Cui
- Department of Cardiovascular, Guang'anmen Hospital, China Academy of Chinese Medical Sciences, Beijing 100053, China.
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Baranovicova E, Hnilicova P, Kalenska D, Kaplan P, Kovalska M, Tatarkova Z, Tomascova A, Lehotsky J. Metabolic Changes Induced by Cerebral Ischemia, the Effect of Ischemic Preconditioning, and Hyperhomocysteinemia. Biomolecules 2022; 12:biom12040554. [PMID: 35454143 PMCID: PMC9032340 DOI: 10.3390/biom12040554] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Revised: 04/01/2022] [Accepted: 04/07/2022] [Indexed: 12/12/2022] Open
Abstract
1H Nuclear Magnetic Resonance (NMR) metabolomics is one of the fundamental tools in the fast-developing metabolomics field. It identifies and quantifies the most abundant metabolites, alterations of which can describe energy metabolism, activated immune response, protein synthesis and catabolism, neurotransmission, and many other factors. This paper summarizes our results of the 1H NMR metabolomics approach to characterize the distribution of relevant metabolites and their alterations induced by cerebral ischemic injury or its combination with hyperhomocysteinemia in the affected tissue and blood plasma in rodents. A decrease in the neurotransmitter pool in the brain tissue likely follows the disordered feasibility of post-ischemic neurotransmission. This decline is balanced by the increased tissue glutamine level with the detected impact on neuronal health. The ischemic injury was also manifested in the metabolomic alterations in blood plasma with the decreased levels of glycolytic intermediates, as well as a post-ischemically induced ketosis-like state with increased plasma ketone bodies. As the 3-hydroxybutyrate can act as a likely neuroprotectant, its post-ischemic increase can suggest its supporting role in balancing ischemic metabolic dysregulation. Furthermore, the 1H NMR approach revealed post-ischemically increased 3-hydroxybutyrate in the remote organs, such as the liver and heart, as well as decreased myocardial glutamate. Ischemic preconditioning, as a proposed protective strategy, was manifested in a lower extent of metabolomic changes and/or their faster recovery in a longitudinal study. The paper also summarizes the pre- and post-ischemic metabolomic changes in the rat hyperhomocysteinemic models. Animals are challenged with hyperglycemia and ketosis-like state. A decrease in several amino acids in plasma follows the onset and progression of hippocampal neuropathology when combined with ischemic injury. The 1H NMR metabolomics approach also offers a high potential for metabolites in discriminatory analysis in the search for potential biomarkers of ischemic injury. Based on our results and the literature data, this paper presents valuable findings applicable in clinical studies and suggests the precaution of a high protein diet, especially foods which are high in Met content and low in B vitamins, in the possible risk of human cerebrovascular neuropathology.
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Affiliation(s)
- Eva Baranovicova
- Biomedical Center BioMed, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia; (E.B.); (P.H.); (A.T.)
| | - Petra Hnilicova
- Biomedical Center BioMed, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia; (E.B.); (P.H.); (A.T.)
| | - Dagmar Kalenska
- Department of Anatomy, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia;
| | - Peter Kaplan
- Department of Medical Biochemistry, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia; (P.K.); (Z.T.)
| | - Maria Kovalska
- Department of Histology and Embryology, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia;
| | - Zuzana Tatarkova
- Department of Medical Biochemistry, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia; (P.K.); (Z.T.)
| | - Anna Tomascova
- Biomedical Center BioMed, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia; (E.B.); (P.H.); (A.T.)
| | - Jan Lehotsky
- Department of Medical Biochemistry, Jessenius Faculty of Medicine, Comenius University in Bratislava, Mala Hora 4, 036 01 Martin, Slovakia; (P.K.); (Z.T.)
- Correspondence:
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14
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Yang L, Yu P, Chen M, Lei B. Mammalian Target of Rapamycin Inhibitor Rapamycin Alleviates 7-Ketocholesterol Induced Inflammatory Responses and Vascular Endothelial Growth Factor Elevation by Regulating MAPK Pathway in Human Retinal Pigment Epithelium Cells. J Ocul Pharmacol Ther 2021; 38:189-200. [PMID: 34936813 DOI: 10.1089/jop.2021.0082] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
Purpose: To validate the protective effect of a mammalian target of rapamycin (mTOR) inhibitor on human retinal pigment epithelium (RPE) cells challenged with 7-ketocholesterol (7-KC) and explored the underlying mechanisms. Methods: Human primary RPE (hRPE) cells and ARPE-19 cells were cultured with or without 10 nM of rapamycin for 6 h before being exposed to 10 μM of 7-KC for 24 h. The transcriptome of 7-KC challenged ARPE-19 cells was investigated by RNA sequencing (RNA-seq). The effects of 7-KC and rapamycin on the viability of ARPE-19 cells were measured with CCK-8. Gene expression was verified by real-time PCR, and protein levels were determined by ELISA or Western blotting. Results: The expression of IL-6, IL-8, and vascular endothelial growth factor (VEGF) in RPE cells was markedly increased after stimulation with 7-KC for 12/24 h compared with the controls. RNA-seq showed that a total of 10,243 genes were differentially expressed, with 5,518 genes upregulated and 4,725 genes downregulated between the 7-KC treated and the control group. Gene ontology and Kyoto Encyclopedia of Genes and Genomes enrichment analysis showed that 7-KC stimulation activated mTOR signaling and other pathways, including adherent junction, MAPK, and Wnt signalings. mTOR inhibitor rapamycin significantly suppressed the elevation of IL-6, IL-8, and VEGF stimulated by 7-KC. Rapamycin not only decreased the level of phosphorylated mTOR, P70S6K, 4EBP1 but also inhibited the activation of MAPK pathway. Conclusions: Inhibition of mTOR signaling pathway suppressed the elevation of inflammatory cytokines IL-6, IL-8, and the angiogenic agent VEGF induced by 7-KC. The protective effect of rapamycin was associated with its downregulation on MAPK pathway.
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Affiliation(s)
- Lin Yang
- Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Henan Eye Institute, Henan Eye Hospital, Zhengzhou, China.,Academy of Medical Sciences, Zhengzhou University, Zhengzhou, China
| | - Peng Yu
- Department of Ophthalmology, People's Hospital of Changshou District, Chongqing, China
| | - Mei Chen
- Centre for Experimental Medicine, Queen's University, Belfast, United Kingdom
| | - Bo Lei
- Zhengzhou University People's Hospital, Henan Provincial People's Hospital, Henan Eye Institute, Henan Eye Hospital, Zhengzhou, China.,Academy of Medical Sciences, Zhengzhou University, Zhengzhou, China
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15
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Zhao W, Chen L, Zhou H, Deng C, Han Q, Chen Y, Wu Q, Li S. Protective effect of carvacrol on liver injury in type 2 diabetic db/db mice. Mol Med Rep 2021; 24:741. [PMID: 34435648 PMCID: PMC8430346 DOI: 10.3892/mmr.2021.12381] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2020] [Accepted: 02/24/2021] [Indexed: 12/11/2022] Open
Abstract
The present study aimed to investigate the protective effect of carvacrol on liver injury in mice with type 2 diabetes mellitus (T2DM) and to assess its potential molecular mechanism. Mice were divided into three groups (n=15/group): Non-diabetic db/m+ mice group, db/db mice group and db/db mice + carvacrol group. In the db/db mice + carvacrol group, db/db mice were administered 10 mg/kg carvacrol daily by gavage for 6 weeks. Fasting blood glucose and insulin levels were separately examined. Pathological changes were observed using hematoxylin and eosin, Masson's trichrome, periodic acid Schiff and reticular fiber staining. In addition, immunohistochemistry, immunofluorescence and western blotting were used to examine the expression levels of Toll-like receptor 4 (TLR4), NF-κB, NALP3, AKT1, phosphorylated (p)-AKT1, insulin receptor (INSR), p-INSR, mTOR, p-mTOR, insulin receptor substrate 1 (IRS1) and p-IRS1 in the liver tissues. The results revealed that carvacrol improved blood glucose and insulin resistance of T2DM db/db mice. After treatment with carvacrol for 6 weeks, the serum levels of TC, TG and LDL-C were markedly reduced, whereas HDL-C levels were significantly increased in db/db mice. Furthermore, carvacrol administration significantly decreased serum ALT and AST levels in db/db mice. Serum BUN, Cre and UA levels were markedly higher in db/db mice compared with those in the control group; however, carvacrol treatment markedly reduced their serum levels in db/db mice. Furthermore, histological examinations confirmed that carvacrol could protect the liver of db/db mice. Carvacrol could ameliorate liver injury induced by T2DM via mediating insulin, TLR4/NF-κB and AKT1/mTOR signaling pathways. The present findings suggested that carvacrol exerted protective effects on the liver in T2DM db/db mice, which could be related to insulin, TLR4/NF-κB and AKT1/mTOR signaling pathways.
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Affiliation(s)
- Wei Zhao
- Department of Endocrinology, The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou 550003, P.R. China
| | - Li Chen
- Department of Prevention and Health Care, The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou 550003, P.R. China
| | - Heng Zhou
- Department of Endocrinology, The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou 550003, P.R. China
| | - Chunyan Deng
- Department of Endocrinology, The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou 550003, P.R. China
| | - Qizhen Han
- Department of Endocrinology, The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou 550003, P.R. China
| | - Yonghua Chen
- Department of Endocrinology, The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou 550003, P.R. China
| | - Qing Wu
- Department of Endocrinology, The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou 550003, P.R. China
| | - Shanshan Li
- Department of Endocrinology, The Second Affiliated Hospital of Guizhou University of Traditional Chinese Medicine, Guiyang, Guizhou 550003, P.R. China
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16
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Bejleri J, Jirström E, Donovan P, Williams DJ, Pfeiffer S. Diagnostic and Prognostic Circulating MicroRNA in Acute Stroke: A Systematic and Bioinformatic Analysis of Current Evidence. J Stroke 2021; 23:162-182. [PMID: 34102753 PMCID: PMC8189849 DOI: 10.5853/jos.2020.05085] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2020] [Accepted: 03/19/2021] [Indexed: 12/11/2022] Open
Abstract
BACKGROUND AND PURPOSE Stroke is the second leading cause of death and disability worldwide and its diagnosis, and assessment of prognosis, remains challenging. There is a need for improved diagnostic and prognostic biomarkers. MicroRNAs (miRNAs) play important roles in the post-transcriptional regulation of gene expression and their secretion and remarkable stability in biofluids highlights their potential as sensitive biomarkers in the diagnosis and prognosis of acute stroke. METHODS We carried out a systematic review to assess current evidence supporting the potential of miRNAs to act as unique diagnostic and prognostic biomarkers in blood samples collected from patients suffering acute stroke within 24 hours of symptoms onset. RESULTS We identified 22 studies eligible for inclusion with 33 dysregulated miRNAs having diagnostic potential in the acute phase of the disease. We identified miR-16, miR-126, and miR-335 as having the highest sensitivity as diagnostic and prognostic biomarkers in acute ischaemic stroke and present original bioinformatic and pathway enrichment analysis of putative miRNA-target interactions. CONCLUSIONS miRNAs represent unique biomarkers which have a promising future in stroke diagnosis and prognosis. However, there is a need for more standardized and consistent methodology for the accurate interpretation and translation of miRNAs as novel specific and sensitive biomarkers into clinical practice.
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Affiliation(s)
- Jorin Bejleri
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland.,Department of Geriatric & Stroke Medicine, Beaumont Hospital, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Elisabeth Jirström
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland.,Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Paul Donovan
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland.,Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - David J Williams
- Department of Geriatric & Stroke Medicine, Beaumont Hospital, Royal College of Surgeons in Ireland, Dublin, Ireland
| | - Shona Pfeiffer
- Department of Physiology and Medical Physics, Royal College of Surgeons in Ireland, Dublin, Ireland.,Centre for Systems Medicine, Royal College of Surgeons in Ireland, Dublin, Ireland
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17
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Brain Insulin Resistance: Focus on Insulin Receptor-Mitochondria Interactions. Life (Basel) 2021; 11:life11030262. [PMID: 33810179 PMCID: PMC8005009 DOI: 10.3390/life11030262] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Revised: 03/12/2021] [Accepted: 03/16/2021] [Indexed: 02/07/2023] Open
Abstract
Current hypotheses implicate insulin resistance of the brain as a pathogenic factor in the development of Alzheimer’s disease and other dementias, Parkinson’s disease, type 2 diabetes, obesity, major depression, and traumatic brain injury. A variety of genetic, developmental, and metabolic abnormalities that lead to disturbances in the insulin receptor signal transduction may underlie insulin resistance. Insulin receptor substrate proteins are generally considered to be the node in the insulin signaling system that is critically involved in the development of insulin insensitivity during metabolic stress, hyperinsulinemia, and inflammation. Emerging evidence suggests that lower activation of the insulin receptor (IR) is another common, while less discussed, mechanism of insulin resistance in the brain. This review aims to discuss causes behind the diminished activation of IR in neurons, with a focus on the functional relationship between mitochondria and IR during early insulin signaling and the related roles of oxidative stress, mitochondrial hypometabolism, and glutamate excitotoxicity in the development of IR insensitivity to insulin.
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18
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Pomytkin I, Pinelis V. Insulin Receptors and Intracellular Ca 2+ Form a Double-Negative Regulatory Feedback Loop Controlling Insulin Sensitivity. F1000Res 2021; 9:598. [PMID: 33552476 PMCID: PMC7845146 DOI: 10.12688/f1000research.24558.2] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/11/2021] [Indexed: 11/20/2022] Open
Abstract
Since the discovery of insulin and insulin receptors (IR) in the brain in 1978, numerous studies have revealed a fundamental role of IR in the central nervous system and its implication in regulating synaptic plasticity, long-term potentiation and depression, neuroprotection, learning and memory, and energy balance. Central insulin resistance has been found in diverse brain disorders including Alzheimer’s disease (AD). Impaired insulin signaling in AD is evident in the activation states of IR and downstream signaling molecules. This is mediated by Aβ oligomer-evoked Ca
2+ influx by activating N-methyl-D-aspartate receptors (NMDARs) with Aβ oligomers directly, or indirectly through Aβ-induced release of glutamate, an endogenous NMDAR ligand. In the present opinion article, we highlight evidence that IR activity and free intracellular Ca
2+ concentration [Ca
2+]
i form a double-negative regulatory feedback loop controlling insulin sensitivity, in which mitochondria play a key role, being involved in adenosine triphosphate (ATP) synthesis and IR activation. We found recently that the glutamate-evoked rise in [Ca
2+]
i inhibits activation of IR and, vice versa, insulin-induced activation of IR inhibits the glutamate-evoked rise in [Ca
2+]
i. In theory, such a double-negative regulatory feedback loop predicts that any condition leading to an increase of [Ca
2+]
i may trigger central insulin resistance and explains why central insulin resistance is implicated in the pathogenesis of AD, with which glutamate excitotoxicity is a comorbid condition. This model also predicts that any intervention aiming to maintain low [Ca
2+]
i may be useful for treating central insulin resistance.
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Affiliation(s)
- Igor Pomytkin
- Department of Advanced Cell Technologies, Sechenov First Moscow State Medical University (Sechenov University), Moscow, Moscow, 119991, Russian Federation
| | - Vsevolod Pinelis
- National Medical Research Center for Children's Health, Russian Ministry of Health, Moscow, 119991, Russian Federation
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19
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Yamakawa G, Brady R, Sun M, McDonald S, Shultz S, Mychasiuk R. The interaction of the circadian and immune system: Desynchrony as a pathological outcome to traumatic brain injury. Neurobiol Sleep Circadian Rhythms 2020; 9:100058. [PMID: 33364525 PMCID: PMC7752723 DOI: 10.1016/j.nbscr.2020.100058] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Revised: 09/11/2020] [Accepted: 10/07/2020] [Indexed: 12/16/2022] Open
Abstract
Traumatic brain injury (TBI) is a complex and costly worldwide phenomenon that can lead to many negative health outcomes including disrupted circadian function. There is a bidirectional relationship between the immune system and the circadian system, with mammalian coordination of physiological activities being controlled by the primary circadian pacemaker in the suprachiasmatic nucleus (SCN) of the hypothalamus. The SCN receives light information from the external environment and in turn synchronizes rhythms throughout the brain and body. The SCN is capable of endogenous self-sustained oscillatory activity through an intricate clock gene negative feedback loop. Following TBI, the response of the immune system can become prolonged and pathophysiological. This detrimental response not only occurs in the brain, but also within the periphery, where a leaky blood brain barrier can permit further infiltration of immune and inflammatory factors. The prolonged and pathological immune response that follows TBI can have deleterious effects on clock gene cycling and circadian function not only in the SCN, but also in other rhythmic areas throughout the body. This could bring about a state of circadian desynchrony where different rhythmic structures are no longer working together to promote optimal physiological function. There are many parallels between the negative symptomology associated with circadian desynchrony and TBI. This review discusses the significant contributions of an immune-disrupted circadian system on the negative symptomology following TBI. The implications of TBI symptomology as a disorder of circadian desynchrony are discussed.
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Affiliation(s)
- G.R. Yamakawa
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
| | - R.D. Brady
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
- Department of Medicine, University of Melbourne, Parkville, Australia
| | - M. Sun
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
| | - S.J. McDonald
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
- Department of Physiology, Anatomy and Microbiology, La Trobe University, Melbourne, Australia
| | - S.R. Shultz
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
- Department of Medicine, University of Melbourne, Parkville, Australia
| | - R. Mychasiuk
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Australia
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20
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Shaughness M, Acs D, Brabazon F, Hockenbury N, Byrnes KR. Role of Insulin in Neurotrauma and Neurodegeneration: A Review. Front Neurosci 2020; 14:547175. [PMID: 33100956 PMCID: PMC7546823 DOI: 10.3389/fnins.2020.547175] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2020] [Accepted: 08/13/2020] [Indexed: 12/15/2022] Open
Abstract
Insulin is a hormone typically associated with pancreatic release and blood sugar regulation. The brain was long thought to be “insulin-independent,” but research has shown that insulin receptors (IR) are expressed on neurons, microglia and astrocytes, among other cells. The effects of insulin on cells within the central nervous system are varied, and can include both metabolic and non-metabolic functions. Emerging data suggests that insulin can improve neuronal survival or recovery after trauma or during neurodegenerative diseases. Further, data suggests a strong anti-inflammatory component of insulin, which may also play a role in both neurotrauma and neurodegeneration. As a result, administration of exogenous insulin, either via systemic or intranasal routes, is an increasing area of focus in research in neurotrauma and neurodegenerative disorders. This review will explore the literature to date on the role of insulin in neurotrauma and neurodegeneration, with a focus on traumatic brain injury (TBI), spinal cord injury (SCI), Alzheimer’s disease (AD) and Parkinson’s disease (PD).
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Affiliation(s)
- Michael Shaughness
- Neuroscience Program, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Deanna Acs
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Fiona Brabazon
- Neuroscience Program, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Nicole Hockenbury
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
| | - Kimberly R Byrnes
- Department of Anatomy, Physiology and Genetics, Uniformed Services University of the Health Sciences, Bethesda, MD, United States
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21
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Clinical Evidence of Antidepressant Effects of Insulin and Anti-Hyperglycemic Agents and Implications for the Pathophysiology of Depression-A Literature Review. Int J Mol Sci 2020; 21:ijms21186969. [PMID: 32971941 PMCID: PMC7554794 DOI: 10.3390/ijms21186969] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/02/2020] [Revised: 08/21/2020] [Accepted: 09/15/2020] [Indexed: 02/07/2023] Open
Abstract
Close connections between depression and type 2 diabetes (T2DM) have been suggested by many epidemiological and experimental studies. Disturbances in insulin sensitivity due to the disruption of various molecular pathways cause insulin resistance, which underpins many metabolic disorders, including diabetes, as well as depression. Several anti-hyperglycemic agents have demonstrated antidepressant properties in clinical trials, probably due to their action on brain targets based on the shared pathophysiology of depression and T2DM. In this article, we review reports of clinical trials examining the antidepressant effect of these medications, including insulin, metformin, glucagon like peptide-1 receptor agonists (GLP-1RA), and peroxisome proliferator-activated receptor (PPAR)-γ agonists, and briefly consider possible molecular mechanisms underlying the associations between amelioration of insulin resistance and improvement of depressive symptoms. In doing so, we intend to suggest an integrative perspective for understanding the pathophysiology of depression.
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22
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Inhibition of Mg 2+ Extrusion Attenuates Glutamate Excitotoxicity in Cultured Rat Hippocampal Neurons. Nutrients 2020; 12:nu12092768. [PMID: 32927908 PMCID: PMC7551965 DOI: 10.3390/nu12092768] [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: 01/01/1970] [Revised: 09/04/2020] [Accepted: 09/08/2020] [Indexed: 02/05/2023] Open
Abstract
Magnesium plays important roles in the nervous system. An increase in the Mg2+ concentration in cerebrospinal fluid enhances neural functions, while Mg2+ deficiency is implicated in neuronal diseases in the central nervous system. We have previously demonstrated that high concentrations of glutamate induce excitotoxicity and elicit a transient increase in the intracellular concentration of Mg2+ due to the release of Mg2+ from mitochondria, followed by a decrease to below steady-state levels. Since Mg2+ deficiency is involved in neuronal diseases, this decrease presumably affects neuronal survival under excitotoxic conditions. However, the mechanism of the Mg2+ decrease and its effect on the excitotoxicity process have not been elucidated. In this study, we demonstrated that inhibitors of Mg2+ extrusion, quinidine and amiloride, attenuated glutamate excitotoxicity in cultured rat hippocampal neurons. A toxic concentration of glutamate induced both Mg2+ release from mitochondria and Mg2+ extrusion from cytosol, and both quinidine and amiloride suppressed only the extrusion. This resulted in the maintenance of a higher Mg2+ concentration in the cytosol than under steady-state conditions during the ten-minute exposure to glutamate. These inhibitors also attenuated the glutamate-induced depression of cellular energy metabolism. Our data indicate the importance of Mg2+ regulation in neuronal survival under excitotoxicity.
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23
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Pomytkin I, Pinelis V. Insulin Receptors and Intracellular Ca 2+ Form a Double-Negative Regulatory Feedback Loop Controlling Insulin Sensitivity. F1000Res 2020; 9:598. [PMID: 33552476 PMCID: PMC7845146 DOI: 10.12688/f1000research.24558.1] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 01/11/2021] [Indexed: 09/07/2023] Open
Abstract
Since the discovery of insulin and insulin receptors (IR) in the brain in 1978, numerous studies have revealed a fundamental role of IR in the central nervous system and its implication in regulating synaptic plasticity, long-term potentiation and depression, neuroprotection, learning and memory, and energy balance. Central insulin resistance has been found in diverse brain disorders including Alzheimer's disease (AD). Impaired insulin signaling in AD is evident in the activation states of IR and downstream signaling molecules. This is mediated by Aβ oligomer-evoked Ca 2+ influx by activating N-methyl-D-aspartate receptors (NMDARs) with Aβ oligomers directly, or indirectly through Aβ-induced release of glutamate, an endogenous NMDAR ligand. In the present opinion article, we highlight evidence that IR activity and free intracellular Ca 2+ concentration [Ca 2+] i form a double-negative regulatory feedback loop controlling insulin sensitivity, in which mitochondria play a key role, being involved in adenosine triphosphate (ATP) synthesis and IR activation. We found recently that the glutamate-evoked rise in [Ca 2+] i inhibits activation of IR and, vice versa, insulin-induced activation of IR inhibits the glutamate-evoked rise in [Ca 2+] i . In theory, such a double-negative regulatory feedback loop predicts that any condition leading to an increase of [Ca 2+] i may trigger central insulin resistance and explains why central insulin resistance is implicated in the pathogenesis of AD, with which glutamate excitotoxicity is a comorbid condition. This model also predicts that any intervention aiming to maintain low [Ca 2+] i may be useful for treating central insulin resistance.
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Affiliation(s)
- Igor Pomytkin
- Department of Advanced Cell Technologies, Sechenov First Moscow State Medical University (Sechenov University), Moscow, Moscow, 119991, Russian Federation
| | - Vsevolod Pinelis
- National Medical Research Center for Children’s Health, Russian Ministry of Health, Moscow, 119991, Russian Federation
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