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1.
Biochim Biophys Acta Mol Basis Dis ; : 166304, 2021 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-34826585

RESUMO

OBJECTIVE: SNAP-25 is one of the key proteins involved in formation of soluble N-ethylmaleimide-sensitive factor attachment protein receptor (SNARE) complexes that are at the core of hormonal secretion and synaptic transmission. Altered expression or function of SNAP-25 can contribute to the development of neuropsychiatric and metabolic disease. A dominant negative (DN) I67T missense mutation in the b-isoform of SNAP-25 (DN-SNAP25mut) mice leads to abnormal interactions within the SNARE complex and impaired exocytotic vesicle recycling, yet the significance of this mutation to any association between the central nervous system and metabolic homeostasis is unknown. METHODS: Here we explored aspects of metabolism, steroid hormone production and neurobehavior of DN-SNAP25mut mice. RESULTS: DN-SNAP25mut mice displayed enhanced insulin function through increased Akt phosphorylation, alongside increased adrenal and gonadal hormone production. In addition, increased anxiety behavior and beigeing of white adipose tissue with increased energy expenditure were observed in mutants. CONCLUSIONS: Our results show that SNAP25 plays an important role in bridging central neurological systems with peripheral metabolic homeostasis, and provide potential insights between metabolic disease and neuropsychiatric disorders in humans.

2.
Transl Psychiatry ; 11(1): 588, 2021 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-34782594

RESUMO

Dysfunction of the glutamate α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor GluA1 subunit and deficits in synaptic plasticity are implicated in schizophrenia and sleep and circadian rhythm disruption. To investigate the role of GluA1 in circadian and sleep behaviour, we used wheel-running, passive-infrared, and video-based home-cage activity monitoring to assess daily rest-activity profiles of GluA1-knockout mice (Gria1-/-). We showed that these mice displayed various circadian abnormalities, including misaligned, fragmented, and more variable rest-activity patterns. In addition, they showed heightened, but transient, behavioural arousal to light→dark and dark→light transitions, as well as attenuated nocturnal-light-induced activity suppression (negative masking). In the hypothalamic suprachiasmatic nuclei (SCN), nocturnal-light-induced cFos signals (a molecular marker of neuronal activity in the preceding ~1-2 h) were attenuated, indicating reduced light sensitivity in the SCN. However, there was no change in the neuroanatomical distribution of expression levels of two neuropeptides-vasoactive intestinal peptide (VIP) and arginine vasopressin (AVP)-differentially expressed in the core (ventromedial) vs. shell (dorsolateral) SCN subregions and both are known to be important for neuronal synchronisation within the SCN and circadian rhythmicity. In the motor cortex (area M1/M2), there was increased inter-individual variability in cFos levels during the evening period, mirroring the increased inter-individual variability in locomotor activity under nocturnal light. Finally, in the spontaneous odour recognition task GluA1 knockouts' short-term memory was impaired due to enhanced attention to the recently encountered familiar odour. These abnormalities due to altered AMPA-receptor-mediated signalling resemble and may contribute to sleep and circadian rhythm disruption and attentional deficits in different modalities in schizophrenia.

3.
iScience ; 24(10): 103142, 2021 Oct 22.
Artigo em Inglês | MEDLINE | ID: mdl-34632336

RESUMO

Circadian rhythms persist in almost all organisms and are crucial for maintaining appropriate timing in physiology and behaviour. Here, we describe a mouse mutant where the central mammalian pacemaker, the suprachiasmatic nucleus (SCN), has been genetically ablated by conditional deletion of the transcription factor Zfhx3 in the developing hypothalamus. Mutants were arrhythmic over the light-dark cycle and in constant darkness. Moreover, rhythms of metabolic parameters were ablated in vivo although molecular oscillations in the liver maintained some rhythmicity. Despite disruptions to SCN cell identity and circuitry, mutants could still anticipate food availability, yet other zeitgebers - including social cues from cage-mates - were ineffective in restoring rhythmicity although activity levels in mutants were altered. This work highlights a critical role for Zfhx3 in the development of a functional SCN, while its genetic ablation further defines the contribution of SCN circuitry in orchestrating physiological and behavioral responses to environmental signals.

4.
Mol Biol Evol ; 38(6): 2468-2474, 2021 05 19.
Artigo em Inglês | MEDLINE | ID: mdl-33560369

RESUMO

The genomes of inbred mice harbor around 50 endogenous murine leukemia virus (MLV) loci, although the specific complement varies greatly between strains. The Gv1 locus is known to control the transcription of endogenous MLVs and to be the dominant determinant of cell-surface presentation of MLV envelope, the GIX antigen. Here, we identify a single Krüppel-associated box zinc finger protein (ZFP) gene, Zfp998, as Gv1 and show it to be necessary and sufficient to determine the GIX+ phenotype. By long-read sequencing of bacterial artificial chromosome clones from 129 mice, the prototypic GIX+ strain, we reveal the source of sufficiency and deficiency as splice-acceptor variations and highlight the varying origins of the chromosomal region encompassing Gv1. Zfp998 becomes the second identified ZFP gene responsible for epigenetic suppression of endogenous MLVs in mice and further highlights the prominent role of this gene family in control of endogenous retroviruses.


Assuntos
Retrovirus Endógenos/fisiologia , Interações Hospedeiro-Patógeno/genética , Vírus da Leucemia Murina/fisiologia , Animais , Interações Hospedeiro-Patógeno/imunologia , Camundongos
5.
Cells ; 10(2)2021 02 10.
Artigo em Inglês | MEDLINE | ID: mdl-33578760

RESUMO

Adenosine diphosphate ribosylation (ADP-ribosylation; ADPr), the addition of ADP-ribose moieties onto proteins and nucleic acids, is a highly conserved modification involved in a wide range of cellular functions, from viral defence, DNA damage response (DDR), metabolism, carcinogenesis and neurobiology. Here we study MACROD1 and MACROD2 (mono-ADP-ribosylhydrolases 1 and 2), two of the least well-understood ADPr-mono-hydrolases. MACROD1 has been reported to be largely localized to the mitochondria, while the MACROD2 genomic locus has been associated with various neurological conditions such as autism, attention deficit hyperactivity disorder (ADHD) and schizophrenia; yet the potential significance of disrupting these proteins in the context of mammalian behaviour is unknown. Therefore, here we analysed both Macrod1 and Macrod2 gene knockout (KO) mouse models in a battery of well-defined, spontaneous behavioural testing paradigms. Loss of Macrod1 resulted in a female-specific motor-coordination defect, whereas Macrod2 disruption was associated with hyperactivity that became more pronounced with age, in combination with a bradykinesia-like gait. These data reveal new insights into the importance of ADPr-mono-hydrolases in aspects of behaviour associated with both mitochondrial and neuropsychiatric disorders.


Assuntos
Comportamento Animal , Hidrolases de Éster Carboxílico/deficiência , Enzimas Reparadoras do DNA/deficiência , Hidrolases/deficiência , Animais , Peso Corporal , Hidrolases de Éster Carboxílico/metabolismo , Enzimas Reparadoras do DNA/metabolismo , Feminino , Marcha , Técnicas de Inativação de Genes , Genótipo , Hidrolases/metabolismo , Masculino , Camundongos Knockout , Atividade Motora , Reprodutibilidade dos Testes
6.
Cell Mol Life Sci ; 78(7): 3503-3524, 2021 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-33340069

RESUMO

Members of the Tre2/Bub2/Cdc16 (TBC), lysin motif (LysM), domain catalytic (TLDc) protein family are associated with multiple neurodevelopmental disorders, although their exact roles in disease remain unclear. For example, nuclear receptor coactivator 7 (NCOA7) has been associated with autism, although almost nothing is known regarding the mode-of-action of this TLDc protein in the nervous system. Here we investigated the molecular function of NCOA7 in neurons and generated a novel mouse model to determine the consequences of deleting this locus in vivo. We show that NCOA7 interacts with the cytoplasmic domain of the vacuolar (V)-ATPase in the brain and demonstrate that this protein is required for normal assembly and activity of this critical proton pump. Neurons lacking Ncoa7 exhibit altered development alongside defective lysosomal formation and function; accordingly, Ncoa7 deletion animals exhibited abnormal neuronal patterning defects and a reduced expression of lysosomal markers. Furthermore, behavioural assessment revealed anxiety and social defects in mice lacking Ncoa7. In summary, we demonstrate that NCOA7 is an important V-ATPase regulatory protein in the brain, modulating lysosomal function, neuronal connectivity and behaviour; thus our study reveals a molecular mechanism controlling endolysosomal homeostasis that is essential for neurodevelopment.


Assuntos
Comportamento Animal , Modelos Animais de Doenças , Transtornos do Neurodesenvolvimento/patologia , Neurônios/patologia , Coativadores de Receptor Nuclear/fisiologia , Estresse Oxidativo , ATPases Vacuolares Próton-Translocadoras/metabolismo , Animais , Endossomos/metabolismo , Feminino , Lisossomos/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Transtornos do Neurodesenvolvimento/etiologia , Transtornos do Neurodesenvolvimento/metabolismo , Neurônios/metabolismo , ATPases Vacuolares Próton-Translocadoras/genética
7.
Antioxidants (Basel) ; 9(8)2020 Aug 13.
Artigo em Inglês | MEDLINE | ID: mdl-32823544

RESUMO

Neurodegenerative disorders, such as Alzheimer's disease, are a global public health burden with poorly understood aetiology. Neuroinflammation and oxidative stress (OS) are undoubtedly hallmarks of neurodegeneration, contributing to disease progression. Protein aggregation and neuronal damage result in the activation of disease-associated microglia (DAM) via damage-associated molecular patterns (DAMPs). DAM facilitate persistent inflammation and reactive oxygen species (ROS) generation. However, the molecular mechanisms linking DAM activation and OS have not been well-defined; thus targeting these cells for clinical benefit has not been possible. In microglia, ROS are generated primarily by NADPH oxidase 2 (NOX2) and activation of NOX2 in DAM is associated with DAMP signalling, inflammation and amyloid plaque deposition, especially in the cerebrovasculature. Additionally, ROS originating from both NOX and the mitochondria may act as second messengers to propagate immune activation; thus intracellular ROS signalling may underlie excessive inflammation and OS. Targeting key kinases in the inflammatory response could cease inflammation and promote tissue repair. Expression of antioxidant proteins in microglia, such as NADPH dehydrogenase 1 (NQO1), is promoted by transcription factor Nrf2, which functions to control inflammation and limit OS. Lipid droplet accumulating microglia (LDAM) may also represent a double-edged sword in neurodegenerative disease by sequestering peroxidised lipids in non-pathological ageing but becoming dysregulated and pro-inflammatory in disease. We suggest that future studies should focus on targeted manipulation of NOX in the microglia to understand the molecular mechanisms driving inflammatory-related NOX activation. Finally, we discuss recent evidence that therapeutic target identification should be unbiased and founded on relevant pathophysiological assays to facilitate the discovery of translatable antioxidant and anti-inflammatory therapeutics.

8.
Hum Mol Genet ; 28(21): 3584-3599, 2019 11 01.
Artigo em Inglês | MEDLINE | ID: mdl-31642482

RESUMO

A common pathological hallmark of amyotrophic lateral sclerosis (ALS) and the related neurodegenerative disorder frontotemporal dementia, is the cellular mislocalization of transactive response DNA-binding protein 43 kDa (TDP-43). Additionally, multiple mutations in the TARDBP gene (encoding TDP-43) are associated with familial forms of ALS. While the exact role for TDP-43 in the onset and progression of ALS remains unclear, the identification of factors that can prevent aberrant TDP-43 localization and function could be clinically beneficial. Previously, we discovered that the oxidation resistance 1 (Oxr1) protein could alleviate cellular mislocalization phenotypes associated with TDP-43 mutations, and that over-expression of Oxr1 was able to delay neuromuscular abnormalities in the hSOD1G93A ALS mouse model. Here, to determine whether Oxr1 can protect against TDP-43-associated phenotypes in vitro and in vivo, we used the same genetic approach in a newly described transgenic mouse expressing the human TDP-43 locus harbouring an ALS disease mutation (TDP-43M337V). We show in primary motor neurons from TDP-43M337V mice that genetically-driven Oxr1 over-expression significantly alleviates cytoplasmic mislocalization of mutant TDP-43. We also further quantified newly-identified, late-onset neuromuscular phenotypes of this mutant line, and demonstrate that neuronal Oxr1 over-expression causes a significant reduction in muscle denervation and neuromuscular junction degeneration in homozygous mutants in parallel with improved motor function and a reduction in neuroinflammation. Together these data support the application of Oxr1 as a viable and safe modifier of TDP-43-associated ALS phenotypes.


Assuntos
Esclerose Amiotrófica Lateral/metabolismo , Proteínas de Ligação a DNA/metabolismo , Proteínas Mitocondriais/metabolismo , Neurônios Motores/metabolismo , Esclerose Amiotrófica Lateral/genética , Esclerose Amiotrófica Lateral/patologia , Esclerose Amiotrófica Lateral/prevenção & controle , Animais , Citoplasma/metabolismo , Proteínas de Ligação a DNA/genética , Feminino , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Proteínas Mitocondriais/genética , Denervação Muscular , Músculos/inervação , Mutação de Sentido Incorreto , Junção Neuromuscular/metabolismo , Transporte Proteico
9.
Cell Rep ; 29(4): 920-931.e7, 2019 10 22.
Artigo em Inglês | MEDLINE | ID: mdl-31644913

RESUMO

Parkinson's disease (PD) is characterized by the death of dopamine neurons in the substantia nigra pars compacta (SNc) and accumulation of α-synuclein. Impaired autophagy has been implicated and activation of autophagy proposed as a treatment strategy. We generate a human α-synuclein-expressing mouse model of PD with macroautophagic failure in dopamine neurons to understand the interaction between impaired macroautophagy and α-synuclein. We find that impaired macroautophagy generates p62-positive inclusions and progressive neuron loss in the SNc. Despite this parkinsonian pathology, motor phenotypes accompanying human α-synuclein overexpression actually improve with impaired macroautophagy. Real-time fast-scan cyclic voltammetry reveals that macroautophagy impairment in dopamine neurons increases evoked extracellular concentrations of dopamine, reduces dopamine uptake, and relieves paired-stimulus depression. Our findings show that impaired macroautophagy paradoxically enhances dopamine neurotransmission, improving movement while worsening pathology, suggesting that changes to dopamine synapse function compensate for and conceal the underlying PD pathogenesis, with implications for therapies that target autophagy.


Assuntos
Autofagia , Neurônios Dopaminérgicos/metabolismo , Doença de Parkinson/metabolismo , Animais , Proteína 7 Relacionada à Autofagia/genética , Proteína 7 Relacionada à Autofagia/metabolismo , Dopamina/metabolismo , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Doença de Parkinson/patologia , Doença de Parkinson/fisiopatologia , Substância Negra/metabolismo , Substância Negra/patologia , Substância Negra/fisiopatologia , Transmissão Sináptica , alfa-Sinucleína/genética , alfa-Sinucleína/metabolismo
10.
Redox Biol ; 24: 101194, 2019 06.
Artigo em Inglês | MEDLINE | ID: mdl-31022673

RESUMO

The Nrf2 signal transduction pathway plays a major role in adaptive responses to oxidative stress and in maintaining adaptive homeostasis, yet Nrf2 signaling undergoes a significant age-dependent decline that is still poorly understood. We used mouse embryonic fibroblasts (MEFs) cultured under hyperoxic conditions of 40% O2, as a model of accelerated ageing. Hyperoxia increased baseline levels of Nrf2 and multiple transcriptional targets (20S Proteasome, Immunoproteasome, Lon protease, NQO1, and HO-1), but resulted in loss of cellular ability to adapt to signaling levels (1.0 µM) of H2O2. In contrast, MEFs cultured at physiologically relevant conditions of 5% O2 exhibited a transient induction of Nrf2 Phase II target genes and stress-protective enzymes (the Lon protease and OXR1) following H2O2 treatment. Importantly, all of these effects have been seen in older cells and organisms. Levels of Two major Nrf2 inhibitors, Bach1 and c-Myc, were strongly elevated by hyperoxia and appeared to exert a ceiling on Nrf2 signaling. Bach1 and c-Myc also increase during ageing and may thus be the mechanism by which adaptive homeostasis is compromised with age.


Assuntos
Adaptação Fisiológica , Envelhecimento/metabolismo , Homeostase , Hiperóxia/metabolismo , Animais , Biologia Computacional/métodos , Fibroblastos/metabolismo , Peróxido de Hidrogênio/metabolismo , Hiperóxia/genética , Camundongos , Estresse Oxidativo , Oxigênio/metabolismo , Complexo de Endopeptidases do Proteassoma/metabolismo , Transdução de Sinais
11.
Dis Model Mech ; 12(2)2019 02 22.
Artigo em Inglês | MEDLINE | ID: mdl-30692144

RESUMO

Loss-of-function mutations in a human AMPA receptor-associated protein, ferric chelate reductase 1-like (FRRS1L), are associated with a devastating neurological condition incorporating choreoathetosis, cognitive deficits and epileptic encephalopathies. Furthermore, evidence from overexpression and ex vivo studies has implicated FRRS1L in AMPA receptor biogenesis, suggesting that changes in glutamatergic signalling might underlie the disorder. Here, we investigated the neurological and neurobehavioural correlates of the disorder using a mouse Frrs1l null mutant. The study revealed several neurological defects that mirrored those seen in human patients. We established that mice lacking Frrs1l suffered from a broad spectrum of early-onset motor deficits with no progressive, age-related deterioration. Moreover, Frrs1l-/- mice were hyperactive, irrespective of test environment, exhibited working memory deficits and displayed significant sleep fragmentation. Longitudinal electroencephalographic (EEG) recordings also revealed abnormal EEG results in Frrs1l-/- mice. Parallel investigations into disease aetiology identified a specific deficiency in AMPA receptor levels in the brain of Frrs1l-/- mice, while the general levels of several other synaptic components remained unchanged, with no obvious alterations in the number of synapses. Furthermore, we established that Frrsl1 deletion results in an increased proportion of immature AMPA receptors, indicated by incomplete glycosylation of GLUA2 (also known as GRIA2) and GLUA4 (also known as GRIA4) AMPA receptor proteins. This incomplete maturation leads to cytoplasmic retention and a reduction of those specific AMPA receptor levels in the postsynaptic membrane. Overall, this study determines, for the first time in vivo, how loss of FRRS1L function can affect glutamatergic signalling, and provides mechanistic insight into the development and progression of a human hyperkinetic disorder.This article has an associated First Person interview with the first author of the paper.


Assuntos
Cognição , Fenômenos Eletrofisiológicos , Proteínas de Membrana/metabolismo , Atividade Motora , Proteínas do Tecido Nervoso/metabolismo , Sistema Nervoso/crescimento & desenvolvimento , Sistema Nervoso/patologia , Receptores de AMPA/metabolismo , Sinapses/metabolismo , Animais , Animais Recém-Nascidos , Tamanho Corporal , Encéfalo/metabolismo , Encéfalo/patologia , Transtornos Cognitivos/patologia , Citoplasma/metabolismo , Glicosilação , Proteínas de Membrana/genética , Camundongos Endogâmicos C57BL , Proteínas do Tecido Nervoso/genética , Sistema Nervoso/fisiopatologia , Sono , Análise de Sobrevida
12.
Neurobiol Dis ; 121: 148-162, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30290270

RESUMO

Mutations in the gene encoding the RNA-binding protein TDP-43 cause amyotrophic lateral sclerosis (ALS), clinically and pathologically indistinguishable from the majority of 'sporadic' cases of ALS, establishing altered TDP-43 function and distribution as a primary mechanism of neurodegeneration. Transgenic mouse models in which TDP-43 is overexpressed only partially recapitulate the key cellular pathology of human ALS, but may also lead to non-specific toxicity. To avoid the potentially confounding effects of overexpression, and to maintain regulated spatio-temporal and cell-specific expression, we generated mice in which an 80 kb genomic fragment containing the intact human TDP-43 locus (either TDP-43WT or TDP-43M337V) and its regulatory regions was integrated into the Rosa26 (Gt(ROSA26)Sor) locus in a single copy. At 3 months of age, TDP-43M337V mice are phenotypically normal but by around 6 months develop progressive motor function deficits associated with loss of neuromuscular junction integrity, leading to a reduced lifespan. RNA sequencing shows that widespread mis-splicing is absent prior to the development of a motor phenotype, though differential expression analysis reveals a distinct transcriptional profile in pre-symptomatic TDP-43M337V spinal cords. Despite the presence of clear motor abnormalities, there was no evidence of TDP-43 cytoplasmic aggregation in vivo at any timepoint. In primary embryonic spinal motor neurons and in embryonic stem cell (ESC)-derived motor neurons, mutant TDP-43 undergoes cytoplasmic mislocalisation, and is associated with altered stress granule assembly and dynamics. Overall, this mouse model provides evidence that ALS may arise through acquired TDP-43 toxicity associated with defective stress granule function. The normal phenotype until 6 months of age can facilitate the study of early pathways underlying ALS.


Assuntos
Esclerose Amiotrófica Lateral/genética , Esclerose Amiotrófica Lateral/metabolismo , Proteínas de Ligação a DNA/genética , Neurônios Motores/metabolismo , Animais , Modelos Animais de Doenças , Feminino , Expressão Gênica , Força da Mão , Humanos , Masculino , Camundongos Endogâmicos C57BL , Camundongos Transgênicos , Neurônios Motores/patologia , Mutação , Junção Neuromuscular/patologia , Proteínas de Ligação a RNA/metabolismo , Teste de Desempenho do Rota-Rod
13.
Mol Neurobiol ; 56(3): 1558-1577, 2019 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29905912

RESUMO

Glucose metabolism is essential for the brain: it not only provides the required energy for cellular function and communication but also participates in balancing the levels of oxidative stress in neurons. Defects in glucose metabolism have been described in neurodegenerative disease; however, it remains unclear how this fundamental process contributes to neuronal cell death in these disorders. Here, we investigated the molecular mechanisms driving the selective neurodegeneration in an ataxic mouse model lacking oxidation resistance 1 (Oxr1) and discovered an unexpected function for this protein as a regulator of the glycolytic enzyme, glucose-6-phosphate isomerase (GPI/Gpi1). Initially, we present a dysregulation of metabolites of glucose metabolism at the pre-symptomatic stage in the Oxr1 knockout cerebellum. We then demonstrate that Oxr1 and Gpi1 physically and functionally interact and that the level of Gpi1 oligomerisation is disrupted when Oxr1 is deleted in vivo. Furthermore, we show that Oxr1 modulates the additional and less well-understood roles of Gpi1 as a cytokine and neuroprotective factor. Overall, our data identify a new molecular function for Oxr1, establishing this protein as important player in neuronal survival, regulating both oxidative stress and glucose metabolism in the brain.


Assuntos
Cerebelo/metabolismo , Glucose-6-Fosfato Isomerase/metabolismo , Glicólise/fisiologia , Proteínas Mitocondriais/metabolismo , Neurônios/metabolismo , Proteínas Nucleares/metabolismo , Animais , Movimento Celular/fisiologia , Glucose/metabolismo , Glucose-6-Fosfato Isomerase/genética , Células HeLa , Humanos , Camundongos , Camundongos Knockout , Proteínas Mitocondriais/genética , Proteínas Nucleares/genética , Estresse Oxidativo/fisiologia
14.
Hum Mol Genet ; 28(4): 584-597, 2019 02 15.
Artigo em Inglês | MEDLINE | ID: mdl-30335140

RESUMO

Mutations in the Tre2/Bub2/Cdc16 (TBC)1 domain family member 24 (TBC1D24) gene are associated with a range of inherited neurological disorders, from drug-refractory lethal epileptic encephalopathy and DOORS syndrome (deafness, onychodystrophy, osteodystrophy, mental retardation, seizures) to non-syndromic hearing loss. TBC1D24 has been implicated in neuronal transmission and maturation, although the molecular function of the gene and the cause of the apparently complex disease spectrum remain unclear. Importantly, heterozygous TBC1D24 mutation carriers have also been reported with seizures, suggesting that haploinsufficiency for TBC1D24 is significant clinically. Here we have systematically investigated an allelic series of disease-associated mutations in neurons alongside a new mouse model to investigate the consequences of TBC1D24 haploinsufficiency to mammalian neurodevelopment and synaptic physiology. The cellular studies reveal that disease-causing mutations that disrupt either of the conserved protein domains in TBC1D24 are implicated in neuronal development and survival and are likely acting as loss-of-function alleles. We then further investigated TBC1D24 haploinsufficiency in vivo and demonstrate that TBC1D24 is also crucial for normal presynaptic function: genetic disruption of Tbc1d24 expression in the mouse leads to an impairment of endocytosis and an enlarged endosomal compartment in neurons with a decrease in spontaneous neurotransmission. These data reveal the essential role for TBC1D24 at the mammalian synapse and help to define common synaptic mechanisms that could underlie the varied effects of TBC1D24 mutations in neurological disease.


Assuntos
Proteínas de Transporte/genética , Anormalidades Craniofaciais/genética , Epilepsia/genética , Deformidades Congênitas da Mão/genética , Perda Auditiva Neurossensorial/genética , Deficiência Intelectual/genética , Unhas Malformadas/genética , Convulsões/genética , Sequência de Aminoácidos/genética , Animais , Anormalidades Craniofaciais/fisiopatologia , Modelos Animais de Doenças , Endocitose/genética , Epilepsia/fisiopatologia , Exoma/genética , Proteínas Ativadoras de GTPase , Regulação da Expressão Gênica , Deformidades Congênitas da Mão/fisiopatologia , Haploinsuficiência , Perda Auditiva Neurossensorial/fisiopatologia , Humanos , Deficiência Intelectual/fisiopatologia , Proteínas de Membrana , Camundongos , Mutação , Unhas Malformadas/fisiopatologia , Proteínas do Tecido Nervoso , Plasticidade Neuronal/genética , Neurônios/metabolismo , Neurônios/patologia , Linhagem , Convulsões/fisiopatologia
15.
Free Radic Biol Med ; 130: 151-162, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30389497

RESUMO

Protein aggregation, oxidative and nitrosative stress are etiological factors common to all major neurodegenerative disorders. Therefore, identifying proteins that function at the crossroads of these essential pathways may provide novel targets for therapy. Oxidation resistance 1 (Oxr1) is a protein proven to be neuroprotective against oxidative stress, although the molecular mechanisms involved remain unclear. Here, we demonstrate that Oxr1 interacts with the multifunctional protein, peroxiredoxin 2 (Prdx2), a potent antioxidant enzyme highly expressed in the brain that can also act as a molecular chaperone. Using a combination of in vitro assays and two animal models, we discovered that expression levels of Oxr1 regulate the degree of oligomerization of Prdx2 and also its post-translational modifications (PTMs), specifically suggesting that Oxr1 acts as a functional switch between the antioxidant and chaperone functions of Prdx2. Furthermore, we showed in the Oxr1 knockout mouse that Prdx2 is aberrantly modified by overoxidation and S-nitrosylation in the cerebellum at the presymptomatic stage; this in-turn affected the oligomerization of Prdx2, potentially impeding its normal functions and contributing to the specific cerebellar neurodegeneration in this mouse model.


Assuntos
Cerebelo/metabolismo , Proteínas Mitocondriais/metabolismo , Doenças Neurodegenerativas/metabolismo , Peroxirredoxinas/metabolismo , Agregação Patológica de Proteínas/metabolismo , Animais , Células Cultivadas , Cerebelo/patologia , Modelos Animais de Doenças , Humanos , Peróxido de Hidrogênio/metabolismo , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Knockout , Proteínas Mitocondriais/genética , Oxirredução , Estresse Oxidativo , Processamento de Proteína Pós-Traducional
16.
Transl Psychiatry ; 8(1): 154, 2018 08 14.
Artigo em Inglês | MEDLINE | ID: mdl-30108203

RESUMO

Sleep EEG spindles have been implicated in attention, sensory processing, synaptic plasticity and memory consolidation. In humans, deficits in sleep spindles have been reported in a wide range of neurological and psychiatric disorders, including schizophrenia. Genome-wide association studies have suggested a link between schizophrenia and genes associated with synaptic plasticity, including the Gria1 gene which codes for the GluA1 subunit of α-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor. Gria1-/- mice exhibit a phenotype relevant for neuropsychiatric disorders, including reduced synaptic plasticity and, at the behavioural level, attentional deficits leading to aberrant salience. In this study we report a striking reduction of EEG power density including the spindle-frequency range (10-15 Hz) during sleep in Gria1-/- mice. The reduction of spindle-activity in Gria1-/- mice was accompanied by longer REM sleep episodes, increased EEG slow-wave activity in the occipital derivation during baseline sleep, and a reduced rate of decline of EEG slow wave activity (0.5-4 Hz) during NREM sleep after sleep deprivation. These data provide a novel link between glutamatergic dysfunction and sleep abnormalities in a schizophrenia-relevant mouse model.


Assuntos
Plasticidade Neuronal/fisiologia , Esquizofrenia/fisiopatologia , Privação do Sono/fisiopatologia , Fases do Sono/fisiologia , Sono/fisiologia , Animais , Modelos Animais de Doenças , Eletroencefalografia , Estudo de Associação Genômica Ampla , Humanos , Masculino , Consolidação da Memória , Camundongos , Camundongos Knockout , Fenótipo , Agitação Psicomotora , Receptores de AMPA/genética , Esquizofrenia/genética
17.
Am J Physiol Renal Physiol ; 315(1): F173-F185, 2018 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-29384414

RESUMO

We recently reported that nuclear receptor coactivator 7 (Ncoa7) is a vacuolar proton pumping ATPase (V-ATPase) interacting protein whose function has not been defined. Ncoa7 is highly expressed in the kidney and partially colocalizes with the V-ATPase in collecting duct intercalated cells (ICs). Here, we hypothesized that targeted deletion of the Ncoa7 gene could affect V-ATPase activity in ICs in vivo. We tested this by analyzing the acid-base status, major electrolytes, and kidney morphology of Ncoa7 knockout (KO) mice. We found that Ncoa7 KO mice, similar to Atp6v1b1 KOs, did not develop severe distal renal tubular acidosis (dRTA), but they exhibited a persistently high urine pH and developed hypobicarbonatemia after acid loading with ammonium chloride. Conversely, they did not develop significant hyperbicarbonatemia and alkalemia after alkali loading with sodium bicarbonate. We also found that ICs were larger and with more developed apical microvilli in Ncoa7 KO compared with wild-type mice, a phenotype previously associated with metabolic acidosis. At the molecular level, the abundance of several V-ATPase subunits, carbonic anhydrase 2, and the anion exchanger 1 was significantly reduced in medullary ICs of Ncoa7 KO mice, suggesting that Ncoa7 is important for maintaining high levels of these proteins in the kidney. We conclude that Ncoa7 is involved in IC function and urine acidification in mice in vivo, likely through modulating the abundance of V-ATPase and other key acid-base regulators in the renal medulla. Consequently, mutations in the NCOA7 gene may also be involved in dRTA pathogenesis in humans.


Assuntos
Equilíbrio Ácido-Base , Acidose Tubular Renal/genética , Deleção de Genes , Túbulos Renais/metabolismo , Coativadores de Receptor Nuclear/genética , Acidose Tubular Renal/patologia , Acidose Tubular Renal/fisiopatologia , Acidose Tubular Renal/urina , Animais , Proteína 1 de Troca de Ânion do Eritrócito/genética , Proteína 1 de Troca de Ânion do Eritrócito/metabolismo , Anidrase Carbônica II/genética , Anidrase Carbônica II/metabolismo , Predisposição Genética para Doença , Concentração de Íons de Hidrogênio , Túbulos Renais/patologia , Túbulos Renais/fisiopatologia , Camundongos Endogâmicos C57BL , Camundongos Knockout , Coativadores de Receptor Nuclear/deficiência , Fenótipo , Urina/química , ATPases Vacuolares Próton-Translocadoras/genética , ATPases Vacuolares Próton-Translocadoras/metabolismo
18.
Mamm Genome ; 28(9-10): 395-406, 2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-28707022

RESUMO

Oxidative stress (OS) arises from an imbalance in the cellular redox state, which can lead to intracellular damage and ultimately cell death. OS occurs as a result of normal ageing, but it is also implicated as a common etiological factor in neurological disease; thus identifying novel proteins that modulate the OS response may facilitate the design of new therapeutic approaches applicable to many disorders. In this review, we describe the recent progress that has been made using a range of genetic approaches to understand a family of proteins that share the highly conserved TLDc domain. We highlight their shared ability to prevent OS-related cell death and their unique functional characteristics, as well as discussing their potential application as new neuroprotective factors. Furthermore, with an increasing number of pathogenic mutations leading to epilepsy and hearing loss being discovered in the TLDc protein TBC1D24, understanding the function of this family has important implications for a range of inherited neurological diseases.


Assuntos
Doenças Neurodegenerativas/genética , Estresse Oxidativo/genética , Animais , Proteínas de Transporte/genética , Proteínas de Transporte/metabolismo , Descoberta de Drogas , Proteínas Ativadoras de GTPase , Humanos , Proteínas de Membrana , Proteínas Mitocondriais , Proteínas do Tecido Nervoso , Doenças Neurodegenerativas/fisiopatologia , Coativadores de Receptor Nuclear/genética , Coativadores de Receptor Nuclear/metabolismo , Domínios Proteicos , Proteínas/genética , Proteínas/metabolismo , Espécies Reativas de Oxigênio/metabolismo
19.
Front Neurosci ; 11: 201, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28484365

RESUMO

Microtubule associated protein tau (MAPT) is involved in the pathogenesis of Alzheimer's disease and many forms of frontotemporal dementia (FTD). We recently reported that Aß-mediated inhibition of hippocampal long-term potentiation (LTP) in mice requires tau. Here, we asked whether expression of human MAPT can restore Aß-mediated inhibition on a mouse Tau-/- background and whether human tau with an FTD-causing mutation (N296H) can interfere with Aß-mediated inhibition of LTP. We used transgenic mouse lines each expressing the full human MAPT locus using bacterial artificial chromosome technology. These lines expressed all six human tau protein isoforms on a Tau-/- background. We found that the human wild-type MAPT H1 locus was able to restore Aß42-mediated impairment of LTP. In contrast, Aß42 did not reduce LTP in slices in two independently generated transgenic lines expressing tau protein with the mutation N296H associated with frontotemporal dementia (FTD). Basal phosphorylation of tau measured as the ratio of AT8/Tau5 immunoreactivity was significantly reduced in N296H mutant hippocampal slices. Our data show that human MAPT is able to restore Aß42-mediated inhibition of LTP in Tau-/- mice. These results provide further evidence that tau protein is central to Aß-induced LTP impairment and provide a valuable tool for further analysis of the links between Aß, human tau and impairment of synaptic function.

20.
Sci Rep ; 7: 43198, 2017 02 24.
Artigo em Inglês | MEDLINE | ID: mdl-28233851

RESUMO

The microtubule-associated protein tau is implicated in various neurodegenerative diseases including Alzheimer's disease, progressive supranuclear palsy and corticobasal degeneration, which are characterized by intracellular accumulation of hyperphosphorylated tau. Mutations in the tau gene MAPT cause frontotemporal dementia with parkinsonism linked to chromosome 17 (FTDP-17). In the human central nervous system, six tau isoforms are expressed, and imbalances in tau isoform ratios are associated with pathology. To date, few animal models of tauopathy allow for the potential influence of these protein isoforms, relying instead on cDNA-based transgene expression. Using the P1-derived artificial chromosome (PAC) technology, we created mouse lines expressing all six tau isoforms from the human MAPT locus, harbouring either the wild-type sequence or the disease-associated N296H mutation on an endogenous Mapt-/- background. Animals expressing N296H mutant tau recapitulated early key features of tauopathic disease, including a tau isoform imbalance and tau hyperphosphorylation in the absence of somatodendritic tau inclusions. Furthermore, N296H animals displayed behavioural anomalies such as hyperactivity, increased time in the open arms of the elevated plus maze and increased immobility during the tail suspension test. The mouse models described provide an excellent model to study the function of wild-type or mutant tau in a highly physiological setting.


Assuntos
Tauopatias/patologia , Proteínas tau/análise , Proteínas tau/genética , Animais , Animais Geneticamente Modificados , Comportamento Animal , Modelos Animais de Doenças , Expressão Gênica , Camundongos , Proteínas Mutantes/análise , Proteínas Mutantes/genética , Isoformas de Proteínas/análise , Isoformas de Proteínas/genética
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