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1.
Cell Metab ; 2024 Jun 19.
Artigo em Inglês | MEDLINE | ID: mdl-38901423

RESUMO

Diet may promote brain health in metabolically impaired older individuals. In an 8-week randomized clinical trial involving 40 cognitively intact older adults with insulin resistance, we examined the effects of 5:2 intermittent fasting and the healthy living diet on brain health. Although intermittent fasting induced greater weight loss, the two diets had comparable effects in improving insulin signaling biomarkers in neuron-derived extracellular vesicles, decreasing the brain-age-gap estimate (reflecting the pace of biological aging of the brain) on magnetic resonance imaging, reducing brain glucose on magnetic resonance spectroscopy, and improving blood biomarkers of carbohydrate and lipid metabolism, with minimal changes in cerebrospinal fluid biomarkers for Alzheimer's disease. Intermittent fasting and healthy living improved executive function and memory, with intermittent fasting benefiting more certain cognitive measures. In exploratory analyses, sex, body mass index, and apolipoprotein E and SLC16A7 genotypes modulated diet effects. The study provides a blueprint for assessing brain effects of dietary interventions and motivates further research on intermittent fasting and continuous diets for brain health optimization. For further information, please see ClinicalTrials.gov registration: NCT02460783.

2.
Trends Endocrinol Metab ; 35(2): 125-141, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38577754

RESUMO

Intermittent short-term fasting (ISTF) and ketogenic diets (KDs) exert overlapping but not identical effects on cell metabolism, function, and resilience. Whereas health benefits of KD are largely mediated by the ketone bodies (KBs), ISTF engages additional adaptive physiological responses. KDs act mainly through inhibition of histone deacetylases (HDACs), reduction of oxidative stress, improvement of mitochondria efficiency, and control of inflammation. Mechanisms of action of ISTF include stimulation of autophagy, increased insulin and leptin sensitivity, activation of AMP-activated protein kinase (AMPK), inhibition of the mechanistic target of rapamycin (mTOR) pathway, bolstering mitochondrial resilience, and suppression of oxidative stress and inflammation. Frequent switching between ketogenic and nonketogenic states may optimize health by increasing stress resistance, while also enhancing cell plasticity and functionality.


Assuntos
Dieta Cetogênica , Humanos , Corpos Cetônicos/metabolismo , Jejum , Estresse Oxidativo/fisiologia , Inflamação
3.
JAMA Psychiatry ; 81(6): 618-623, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38568615

RESUMO

Importance: Psychiatric disorders may come and go with symptoms changing over a lifetime. This suggests the need for a paradigm shift in diagnosis and treatment. Here we present a fresh look inspired by dynamical systems theory. This theory is used widely to explain tipping points, cycles, and chaos in complex systems ranging from the climate to ecosystems. Observations: In the dynamical systems view, we propose the healthy state has a basin of attraction representing its resilience, while disorders are alternative attractors in which the system can become trapped. Rather than an immutable trait, resilience in this approach is a dynamical property. Recent work has demonstrated the universality of generic dynamical indicators of resilience that are now employed globally to monitor the risks of collapse of complex systems, such as tropical rainforests and tipping elements of the climate system. Other dynamical systems tools are used in ecology and climate science to infer causality from time series. Moreover, experiences in ecological restoration confirm the theoretical prediction that under some conditions, short interventions may invoke long-term success when they flip the system into an alternative basin of attraction. All this implies practical applications for psychiatry, as are discussed in part 2 of this article. Conclusions and Relevance: Work in the field of dynamical systems points to novel ways of inferring causality and quantifying resilience from time series. Those approaches have now been tried and tested in a range of complex systems. The same tools may help monitoring and managing resilience of the healthy state as well as psychiatric disorders.


Assuntos
Transtornos Mentais , Humanos , Transtornos Mentais/psicologia , Resiliência Psicológica , Teoria de Sistemas
4.
JAMA Psychiatry ; 81(6): 624-630, 2024 Jun 01.
Artigo em Inglês | MEDLINE | ID: mdl-38568618

RESUMO

Importance: Dynamical systems theory is widely used to explain tipping points, cycles, and chaos in complex systems ranging from the climate to ecosystems. It has been suggested that the same theory may be used to explain the nature and dynamics of psychiatric disorders, which may come and go with symptoms changing over a lifetime. Here we review evidence for the practical applicability of this theory and its quantitative tools in psychiatry. Observations: Emerging results suggest that time series of mood and behavior may be used to monitor the resilience of patients using the same generic dynamical indicators that are now employed globally to monitor the risks of collapse of complex systems, such as tropical rainforest and tipping elements of the climate system. Other dynamical systems tools used in ecology and climate science open ways to infer personalized webs of causality for patients that may be used to identify targets for intervention. Meanwhile, experiences in ecological restoration help make sense of the occasional long-term success of short interventions. Conclusions and Relevance: Those observations, while promising, evoke follow-up questions on how best to collect dynamic data, infer informative timescales, construct mechanistic models, and measure the effect of interventions on resilience. Done well, monitoring resilience to inform well-timed interventions may be integrated into approaches that give patients an active role in the lifelong challenge of managing their resilience and knowing when to seek professional help.


Assuntos
Transtornos Mentais , Humanos , Transtornos Mentais/psicologia , Transtornos Mentais/terapia , Resiliência Psicológica , Teoria de Sistemas
5.
Prog Neurobiol ; 233: 102568, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38216113

RESUMO

The Topoisomerase 3B (Top3b) - Tudor domain containing 3 (Tdrd3) protein complex is the only dual-activity topoisomerase complex that can alter both DNA and RNA topology in animals. TOP3B mutations in humans are associated with schizophrenia, autism and cognitive disorders; and Top3b-null mice exhibit several phenotypes observed in animal models of psychiatric and cognitive disorders, including impaired cognitive and emotional behaviors, aberrant neurogenesis and synaptic plasticity, and transcriptional defects. Similarly, human TDRD3 genomic variants have been associated with schizophrenia, verbal short-term memory and educational attainment. However, the importance of Tdrd3 in normal brain function has not been examined in animal models. Here we generated a Tdrd3-null mouse strain and demonstrate that these mice display both shared and unique defects when compared to Top3b-null mice. Shared defects were observed in cognitive behaviors, synaptic plasticity, adult neurogenesis, newborn neuron morphology, and neuronal activity-dependent transcription; whereas defects unique to Tdrd3-deficient mice include hyperactivity, changes in anxiety-like behaviors, olfaction, increased new neuron complexity, and reduced myelination. Interestingly, multiple genes critical for neurodevelopment and cognitive function exhibit reduced levels in mature but not nascent transcripts. We infer that the entire Top3b-Tdrd3 complex is essential for normal brain function, and that defective post-transcriptional regulation could contribute to cognitive and psychiatric disorders.


Assuntos
Disfunção Cognitiva , Regulação da Expressão Gênica , Animais , Humanos , Camundongos , Sequência de Aminoácidos , Neurogênese/genética , Plasticidade Neuronal/genética , Proteínas/genética , Proteínas/metabolismo
6.
Cell Metab ; 36(2): 315-337, 2024 02 06.
Artigo em Inglês | MEDLINE | ID: mdl-38211591

RESUMO

Animals live in habitats fraught with a range of environmental challenges to their bodies and brains. Accordingly, cells and organ systems have evolved stress-responsive signaling pathways that enable them to not only withstand environmental challenges but also to prepare for future challenges and function more efficiently. These phylogenetically conserved processes are the foundation of the hormesis principle, in which single or repeated exposures to low levels of environmental challenges improve cellular and organismal fitness and raise the probability of survival. Hormetic principles have been most intensively studied in physical exercise but apply to numerous other challenges known to improve human health (e.g., intermittent fasting, cognitive stimulation, and dietary phytochemicals). Here we review the physiological mechanisms underlying hormesis-based neuroplasticity and neuroprotection. Approaching natural resilience from the lens of hormesis may reveal novel methods for optimizing brain function and lowering the burden of neurological disorders.


Assuntos
Hormese , Neuroproteção , Animais , Humanos , Hormese/fisiologia , Plasticidade Neuronal
7.
Front Hum Neurosci ; 17: 1215291, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-38021223

RESUMO

Introduction: Transcranial Magnetic Stimulation (TMS) is a noninvasive technique that uses pulsed magnetic fields to affect the physiology of the brain and central nervous system. Repetitive TMS (rTMS) has been used to study and treat several neurological conditions, but its complex molecular basis is largely unexplored. Methods: Utilizing three experimental rat models (in vitro, ex vivo, and in vivo) and employing genome-wide microarray analysis, our study reveals the extensive impact of rTMS treatment on gene expression patterns. Results: These effects are observed across various stimulation protocols, in diverse tissues, and are influenced by time and age. Notably, rTMS-induced alterations in gene expression span a wide range of biological pathways, such as glutamatergic, GABAergic, and anti-inflammatory pathways, ion channels, myelination, mitochondrial energetics, multiple neuron-and synapse-specific genes. Discussion: This comprehensive transcriptional analysis induced by rTMS stimulation serves as a foundational characterization for subsequent experimental investigations and the exploration of potential clinical applications.

8.
Elife ; 122023 09 28.
Artigo em Inglês | MEDLINE | ID: mdl-37769126

RESUMO

Intermittent fasting (IF) has been shown to reduce cardiovascular risk factors in both animals and humans, and can protect the heart against ischemic injury in models of myocardial infarction. However, the underlying molecular mechanisms behind these effects remain unclear. To shed light on the molecular and cellular adaptations of the heart to IF, we conducted comprehensive system-wide analyses of the proteome, phosphoproteome, and transcriptome, followed by functional analysis. Using advanced mass spectrometry, we profiled the proteome and phosphoproteome of heart tissues obtained from mice that were maintained on daily 12- or 16 hr fasting, every-other-day fasting, or ad libitum control feeding regimens for 6 months. We also performed RNA sequencing to evaluate whether the observed molecular responses to IF occur at the transcriptional or post-transcriptional levels. Our analyses revealed that IF significantly affected pathways that regulate cyclic GMP signaling, lipid and amino acid metabolism, cell adhesion, cell death, and inflammation. Furthermore, we found that the impact of IF on different metabolic processes varied depending on the length of the fasting regimen. Short IF regimens showed a higher correlation of pathway alteration, while longer IF regimens had an inverse correlation of metabolic processes such as fatty acid oxidation and immune processes. Additionally, functional echocardiographic analyses demonstrated that IF enhances stress-induced cardiac performance. Our systematic multi-omics study provides a molecular framework for understanding how IF impacts the heart's function and its vulnerability to injury and disease.


Assuntos
Jejum Intermitente , Multiômica , Humanos , Camundongos , Animais , Proteoma , Jejum/fisiologia , Metabolismo Energético
9.
Rev Fish Sci Aquac ; 31(3): 342-371, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-37621745

RESUMO

The Hudson River (HR) Estuary has a long history of pollution with a variety of contaminants including PCBs, and dioxins. In fact, 200 miles of the mainstem HR is designated a U.S. federal Superfund site, the largest in the nation, because of PCB contamination. The tidal HR hosts the southernmost spawning population of Atlantic tomcod, and studies revealed a correlation between exposure of juveniles to warm water temperature during summer to abundance of spawning adults of the same cohort in the following winter. Further, a battery of mechanistically linked biomarkers, ranging from the molecular to the population levels, were significantly impacted from contaminant exposures of the HR tomcod population. In response to xenobiotic insult, the HR tomcod population developed resistance to PCB sand TCDD toxicity resulting from a deletion in the aryl hydrocarbon receptor2 (AHR2) gene. Furthermore, RNA-Seq analysis of global gene expression demonstrated that effects of the AHR2 polymorphism were far more pervasive than anticipated. The most highly PCB-contaminated sediments in the upper HR were dredged between 2009 and 2015 with the objective of lowering PCB concentrations in fishes in the lower HR. Success of the remediation project has been controversial. These observations suggest that tomcod provides an informative model to evaluate the efficacy of HR PCB remediation efforts on downriver fish populations and possible interactive effects between contaminant exposure and a warming environment.

10.
Res Sq ; 2023 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-36909584

RESUMO

The Topoisomerase 3B (Top3b) - Tudor domain containing 3 (Tdrd3) protein complex is the only dual-activity topoisomerase complex in animals that can alter the topology of both DNA and RNA. TOP3B mutations in humans are associated with schizophrenia, autism and cognitive disorders; and Top3b-null mice exhibit several phenotypes observed in animal models of psychiatric and cognitive disorders, including impairments in cognitive and emotional behaviors, aberrant neurogenesis and synaptic plasticity, and transcriptional defects. Similarly, human TDRD3 genomic variants have been associated with schizophrenia, verbal shorten-memory and learning, and educational attainment. However, the importance of Tdrd3 in normal brain function has not been examined in animal models. Here we built a Tdrd3-null mouse strain and demonstrate that these mice display both shared and unique defects when compared to Top3b-null mice. Shared defects were observed in cognitive behaviors, synaptic plasticity, adult neurogenesis, newborn neuron morphology, and neuronal activity-dependent transcription; whereas defects unique to Tdrd3-deficient mice include hyperactivity, changes in anxiety-like behaviors, increased new neuron complexity, and reduced myelination. Interestingly, multiple genes critical for neurodevelopment and cognitive function exhibit reduced levels in mature but not nascent transcripts. We infer that the entire Top3b-Tdrd3 complex is essential for normal brain function, and that defective post-transcriptional regulation could contribute to cognitive impairment and psychiatric disorders.

11.
Trends Neurosci ; 46(5): 365-376, 2023 05.
Artigo em Inglês | MEDLINE | ID: mdl-36907678

RESUMO

Huntington's disease (HD) is a dominantly inherited neurodegenerative disorder caused by a trinucleotide repeat expansion in the huntingtin gene resulting in long stretches of polyglutamine repeats in the huntingtin protein. The disease involves progressive degeneration of neurons in the striatum and cerebral cortex resulting in loss of control of motor function, psychiatric problems, and cognitive deficits. There are as yet no treatments that can slow disease progression in HD. Recent advances in gene editing using clustered regularly interspaced short palindromic repeats (CRISPR)-CRISPR-associated protein 9 (Cas9) systems and demonstrations of their ability to correct gene mutations in animal models of a range of diseases suggest that gene editing may prove effective in preventing or ameliorating HD. Here we describe (i) potential CRISPR-Cas designs and cellular delivery methods for the correction of mutant genes that cause inherited diseases, and (ii) recent preclinical findings demonstrating the efficacy of such gene-editing approaches in animal models, with a focus on HD.


Assuntos
Doença de Huntington , Doenças Neurodegenerativas , Animais , Edição de Genes/métodos , Doença de Huntington/genética , Doença de Huntington/terapia , Sistemas CRISPR-Cas/genética , Doenças Neurodegenerativas/genética , Mutação , Modelos Animais de Doenças
13.
Neuromolecular Med ; 25(1): 27-39, 2023 03.
Artigo em Inglês | MEDLINE | ID: mdl-35749057

RESUMO

Aging is the major risk factor for Alzheimer's disease (AD). Mitochondrial dysfunction and neuronal network hyperexcitability are two age-related alterations implicated in AD pathogenesis. We found that levels of the mitochondrial protein deacetylase sirtuin-3 (SIRT3) are significantly reduced, and consequently mitochondria protein acetylation is increased in brain cells during aging. SIRT3-deficient mice exhibit robust mitochondrial protein hyperacetylation and reduced mitochondrial mass during aging. Moreover, SIRT3-deficient mice exhibit epileptiform and burst-firing electroencephalogram activity indicating neuronal network hyperexcitability. Both aging and SIRT3 deficiency result in increased sensitivity to kainic acid-induced seizures. Exposure of cultured cerebral cortical neurons to amyloid ß-peptide (Aß) results in a reduction in SIRT3 levels and SIRT3-deficient neurons exhibit heightened sensitivity to Aß toxicity. Finally, SIRT3 haploinsufficiency in middle-aged App/Ps1 double mutant transgenic mice results in a significant increase in Aß load compared with App/Ps1 double mutant mice with normal SIRT3 levels. Collectively, our findings suggest that SIRT3 plays an important role in protecting neurons against Aß pathology and excitotoxicity.


Assuntos
Doença de Alzheimer , Sirtuína 3 , Camundongos , Animais , Peptídeos beta-Amiloides/toxicidade , Peptídeos beta-Amiloides/metabolismo , Sirtuína 3/genética , Sirtuína 3/metabolismo , Precursor de Proteína beta-Amiloide/metabolismo , Doença de Alzheimer/metabolismo , Neurônios/metabolismo , Camundongos Transgênicos , Mitocôndrias/metabolismo , Proteínas Mitocondriais , Modelos Animais de Doenças
14.
Cells ; 11(15)2022 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-35954260

RESUMO

Dysfunctional mitochondrial quality control (MQC) is implicated in the pathogenesis of Parkinson's disease (PD). The improper selection of mitochondria for mitophagy increases reactive oxygen species (ROS) levels and lowers ATP levels. The downstream effects include oxidative damage, failure to maintain proteostasis and ion gradients, and decreased NAD+ and NADPH levels, resulting in insufficient energy metabolism and neurotransmitter synthesis. A ketosis-based metabolic therapy that increases the levels of (R)-3-hydroxybutyrate (BHB) may reverse the dysfunctional MQC by partially replacing glucose as an energy source, by stimulating mitophagy, and by decreasing inflammation. Fasting can potentially raise cytoplasmic NADPH levels by increasing the mitochondrial export and cytoplasmic metabolism of ketone body-derived citrate that increases flux through isocitrate dehydrogenase 1 (IDH1). NADPH is an essential cofactor for nitric oxide synthase, and the nitric oxide synthesized can diffuse into the mitochondrial matrix and react with electron transport chain-synthesized superoxide to form peroxynitrite. Excessive superoxide and peroxynitrite production can cause the opening of the mitochondrial permeability transition pore (mPTP) to depolarize the mitochondria and activate PINK1-dependent mitophagy. Both fasting and exercise increase ketogenesis and increase the cellular NAD+/NADH ratio, both of which are beneficial for neuronal metabolism. In addition, both fasting and exercise engage the adaptive cellular stress response signaling pathways that protect neurons against the oxidative and proteotoxic stress implicated in PD. Here, we discuss how intermittent fasting from the evening meal through to the next-day lunch together with morning exercise, when circadian NAD+/NADH is most oxidized, circadian NADP+/NADPH is most reduced, and circadian mitophagy gene expression is high, may slow the progression of PD.


Assuntos
Doença de Parkinson , Terapia por Exercício , Jejum , Humanos , Mitocôndrias/metabolismo , NAD/metabolismo , NADP/metabolismo , Doença de Parkinson/metabolismo , Ácido Peroxinitroso/metabolismo , Superóxidos/metabolismo
15.
Geroscience ; 44(4): 2171-2194, 2022 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-35357643

RESUMO

Intermittent fasting (IF) remains the most effective intervention to achieve robust anti-aging effects and attenuation of age-related diseases in various species. Epigenetic modifications mediate the biological effects of several environmental factors on gene expression; however, no information is available on the effects of IF on the epigenome. Here, we first found that IF for 3 months caused modulation of H3K9 trimethylation (H3K9me3) in the cerebellum, which in turn orchestrated a plethora of transcriptomic changes involved in robust metabolic switching processes commonly observed during IF. Second, a portion of both the epigenomic and transcriptomic modulations induced by IF was remarkably preserved for at least 3 months post-IF refeeding, indicating that memory of IF-induced epigenetic changes was maintained. Notably, though, we found that termination of IF resulted in a loss of H3K9me3 regulation of the transcriptome. Collectively, our study characterizes the novel effects of IF on the epigenetic-transcriptomic axis, which controls myriad metabolic processes. The comprehensive analyses undertaken in this study reveal a molecular framework for understanding how IF impacts the metabolo-epigenetic axis of the brain and will serve as a valuable resource for future research.


Assuntos
Epigenômica , Transcriptoma , Jejum , Perfilação da Expressão Gênica , Encéfalo
16.
Br J Cancer ; 126(8): 1157-1167, 2022 05.
Artigo em Inglês | MEDLINE | ID: mdl-34912072

RESUMO

BACKGROUND: Excess adiposity at diagnosis and weight gain during chemotherapy is associated with tumour recurrence and chemotherapy toxicity. We assessed the efficacy of intermittent energy restriction (IER) vs continuous energy restriction (CER) for weight control and toxicity reduction during chemotherapy. METHODS: One hundred and seventy-two women were randomised to follow IER or CER throughout adjuvant/neoadjuvant chemotherapy. Primary endpoints were weight and body fat change. Secondary endpoints included chemotherapy toxicity, cardiovascular risk markers, and correlative markers of metabolism, inflammation and oxidative stress. RESULTS: Primary analyses showed non-significant reductions in weight (-1.1 (-2.4 to +0.2) kg, p = 0.11) and body fat (-1.0 (-2.1 to +0.1) kg, p = 0.086) in IER compared with CER. Predefined secondary analyses adjusted for body water showed significantly greater reductions in weight (-1.4 (-2.5 to -0.2) kg, p = 0.024) and body fat (-1.1 (-2.1 to -0.2) kg, p = 0.046) in IER compared with CER. Incidence of grade 3/4 toxicities were comparable overall (IER 31.0 vs CER 36.5%, p = 0.45) with a trend to fewer grade 3/4 toxicities with IER (18%) vs CER (31%) during cycles 4-6 of primarily taxane therapy (p = 0.063). CONCLUSIONS: IER is feasible during chemotherapy. The potential efficacy for weight control and reducing toxicity needs to be tested in future larger trials. CLINICAL TRIAL REGISTRATION: ISRCTN04156504.


Assuntos
Neoplasias da Mama , Dieta Redutora , Neoplasias da Mama/tratamento farmacológico , Restrição Calórica , Feminino , Humanos , Recidiva Local de Neoplasia , Obesidade
17.
Nat Neurosci ; 25(1): 26-38, 2022 01.
Artigo em Inglês | MEDLINE | ID: mdl-34916658

RESUMO

Triggering receptor expressed on myeloid cell 2 (TREM2) is linked to risk of neurodegenerative disease. However, the function of TREM2 in neurodegeneration is still not fully understood. Here, we investigated the role of microglial TREM2 in TAR DNA-binding protein 43 (TDP-43)-related neurodegeneration using virus-mediated and transgenic mouse models. We found that TREM2 deficiency impaired phagocytic clearance of pathological TDP-43 by microglia and enhanced neuronal damage and motor impairments. Mass cytometry analysis revealed that human TDP-43 (hTDP-43) induced a TREM2-dependent subpopulation of microglia with high CD11c expression and phagocytic ability. Using mass spectrometry (MS) and surface plasmon resonance (SPR) analysis, we further demonstrated an interaction between TDP-43 and TREM2 in vitro and in vivo as well as in human tissues from individuals with amyotrophic lateral sclerosis (ALS). We computationally identified regions within hTDP-43 that interact with TREM2. Our data highlight that TDP-43 is a possible ligand for microglial TREM2 and that this interaction mediates neuroprotection of microglia in TDP-43-related neurodegeneration.


Assuntos
Proteínas de Ligação a DNA , Glicoproteínas de Membrana , Microglia , Doenças Neurodegenerativas , Receptores Imunológicos , Animais , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Camundongos , Camundongos Transgênicos , Microglia/metabolismo , Doenças Neurodegenerativas/metabolismo , Neuroproteção , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo
18.
Proc Natl Acad Sci U S A ; 118(37)2021 09 14.
Artigo em Inglês | MEDLINE | ID: mdl-34497121

RESUMO

Alzheimer's disease (AD) is a progressive and fatal neurodegenerative disorder. Impaired neuronal bioenergetics and neuroinflammation are thought to play key roles in the progression of AD, but their interplay is not clear. Nicotinamide adenine dinucleotide (NAD+) is an important metabolite in all human cells in which it is pivotal for multiple processes including DNA repair and mitophagy, both of which are impaired in AD neurons. Here, we report that levels of NAD+ are reduced and markers of inflammation increased in the brains of APP/PS1 mutant transgenic mice with beta-amyloid pathology. Treatment of APP/PS1 mutant mice with the NAD+ precursor nicotinamide riboside (NR) for 5 mo increased brain NAD+ levels, reduced expression of proinflammatory cytokines, and decreased activation of microglia and astrocytes. NR treatment also reduced NLRP3 inflammasome expression, DNA damage, apoptosis, and cellular senescence in the AD mouse brains. Activation of cyclic GMP-AMP synthase (cGAS) and stimulator of interferon genes (STING) are associated with DNA damage and senescence. cGAS-STING elevation was observed in the AD mice and normalized by NR treatment. Cell culture experiments using microglia suggested that the beneficial effects of NR are, in part, through a cGAS-STING-dependent pathway. Levels of ectopic (cytoplasmic) DNA were increased in APP/PS1 mutant mice and human AD fibroblasts and down-regulated by NR. NR treatment induced mitophagy and improved cognitive and synaptic functions in APP/PS1 mutant mice. Our findings suggest a role for NAD+ depletion-mediated activation of cGAS-STING in neuroinflammation and cellular senescence in AD.


Assuntos
Doença de Alzheimer/complicações , Senescência Celular , Suplementos Nutricionais , Proteínas de Membrana/metabolismo , NAD/administração & dosagem , Doenças Neuroinflamatórias/tratamento farmacológico , Nucleotidiltransferases/metabolismo , Animais , Humanos , Proteínas de Membrana/genética , Camundongos , Camundongos Transgênicos , Doenças Neuroinflamatórias/etiologia , Doenças Neuroinflamatórias/patologia , Niacinamida/administração & dosagem , Niacinamida/análogos & derivados , Nucleotidiltransferases/genética , Compostos de Piridínio/administração & dosagem
19.
Theranostics ; 11(18): 8855-8873, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34522215

RESUMO

Mitochondrial dysfunction and oxidative stress are frequently observed in the early stages of Alzheimer's disease (AD). Studies have shown that presenilin-1 (PS1), the catalytic subunit of γ-secretase whose mutation is linked to familial AD (FAD), localizes to the mitochondrial membrane and regulates its homeostasis. Thus, we investigated how five PS1 mutations (A431E, E280A, H163R, M146V, and Δexon9) observed in FAD affect mitochondrial functions. Methods: We used H4 glioblastoma cell lines genetically engineered to inducibly express either the wild-type PS1 or one of the five PS1 mutants in order to examine mitochondrial morphology, dynamics, membrane potential, ATP production, mitochondria-associated endoplasmic reticulum (ER) membranes (MAMs), oxidative stress, and bioenergetics. Furthermore, we used brains of PS1M146V knock-in mice, 3xTg-AD mice, and human AD patients in order to investigate the role of PS1 in regulating MAMs formation. Results: Each PS1 mutant exhibited slightly different mitochondrial dysfunction. Δexon9 mutant induced mitochondrial fragmentation while A431E, E280A, H163R, and M146V mutants increased MAMs formation. A431E, E280A, M146V, and Δexon9 mutants also induced mitochondrial ROS production. A431E mutant impaired both complex I and peroxidase activity while M146V mutant only impaired peroxidase activity. All PS1 mutants compromised mitochondrial membrane potential and cellular ATP levels were reduced by A431E, M146V, and Δexon9 mutants. Through comparative profiling of hippocampal gene expression in PS1M146V knock-in mice, we found that PS1M146V upregulates Atlastin 2 (ATL2) expression level, which increases ER-mitochondria contacts. Down-regulation of ATL2 after PS1 mutant induction rescued abnormally elevated ER-mitochondria interactions back to the normal level. Moreover, ATL2 expression levels were significantly elevated in the brains of 3xTg-AD mice and AD patients. Conclusions: Overall, our findings suggest that each of the five FAD-linked PS1 mutations has a deleterious effect on mitochondrial functions in a variety of ways. The adverse effects of PS1 mutations on mitochondria may contribute to MAMs formation and oxidative stress resulting in an accelerated age of disease onset in people harboring mutant PS1.


Assuntos
Doença de Alzheimer/fisiopatologia , Mitocôndrias/fisiologia , Presenilina-1/genética , Trifosfato de Adenosina/metabolismo , Doença de Alzheimer/genética , Animais , Linhagem Celular Tumoral , Retículo Endoplasmático/metabolismo , Técnicas de Introdução de Genes/métodos , Humanos , Potencial da Membrana Mitocondrial/fisiologia , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Mutação , Estresse Oxidativo/fisiologia , Presenilina-1/metabolismo
20.
Prog Neurobiol ; 204: 102089, 2021 09.
Artigo em Inglês | MEDLINE | ID: mdl-34118354

RESUMO

Brain glucose metabolism, including glycolysis, the pentose phosphate pathway, and glycogen turnover, produces ATP for energetic support and provides the precursors for the synthesis of biological macromolecules. Although glucose metabolism in neurons and astrocytes has been extensively studied, the glucose metabolism of microglia and oligodendrocytes, and their interactions with neurons and astrocytes, remain critical to understand brain function. Brain regions with heterogeneous cell composition and cell-type-specific profiles of glucose metabolism suggest that metabolic networks within the brain are complex. Signal transduction proteins including those in the Wnt, GSK-3ß, PI3K-AKT, and AMPK pathways are involved in regulating these networks. Additionally, glycolytic enzymes and metabolites, such as hexokinase 2, acetyl-CoA, and enolase 2, are implicated in the modulation of cellular function, microglial activation, glycation, and acetylation of biomolecules. Given these extensive networks, glucose metabolism dysfunction in the whole brain or specific cell types is strongly associated with neurologic pathology including ischemic brain injury and neurodegenerative disorders. This review characterizes the glucose metabolism networks of the brain based on molecular signaling and cellular and regional interactions, and elucidates glucose metabolism-based mechanisms of neurological diseases and therapeutic approaches that may ameliorate metabolic abnormalities in those diseases.


Assuntos
Encéfalo , Metabolismo dos Carboidratos , Glucose , Glicogênio Sintase Quinase 3 beta , Glicólise , Fosfatidilinositol 3-Quinases
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