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1.
Brain Behav Immun ; 2020 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-32450195

RESUMO

The transcription factor nuclear factor kappa B (NF-κB) regulates the expression of many inflammatory genes that are overexpressed in a subset of people with schizophrenia. Transcriptional reduction in one NF-κB inhibitor, Human Immunodeficiency Virus Enhancer Binding Protein 2 (HIVEP2), is found in the brain of patients, aligning with evidence of NF-κB over-activity. Cellular co-expression of HIVEP2 and cytokine transcripts is a prerequisite for a direct effect of HIVEP2 on pro-inflammatory transcription, and we do not know if changes in HIVEP2 and markers of neuroinflammation are occurring in the same brain cell type. We performed in situ hybridisation on postmortem dorsolateral prefrontal cortex tissue to map and compare the expression of HIVEP2 and Serpin Family A Member 3 (SERPINA3), one of the most consistently increased inflammatory genes in schizophrenia, between schizophrenia patients and controls. We find that HIVEP2 expression is neuronal and is decreased in almost all grey matter cortical layers in schizophrenia patients with neuroinflammation, and that SERPINA3 is increased in the dorsolateral prefrontal cortex grey matter and white matter in the same group of patients. We are the first to map the upregulation of SERPINA3 to astrocytes and to some neurons, and find evidence to suggest that blood vessel-associated astrocytes are the main cellular source of SERPINA3 in the schizophrenia cortex. We show that a lack of HIVEP2 in mice does not cause astrocytic upregulation of Serpina3n but does induce its transcription in neurons. We speculate that HIVEP2 downregulation is not a direct cause of astrocytic pro-inflammatory cytokine synthesis in schizophrenia but may contribute to neuronally-mediated neuroinflammation.

2.
J Mol Neurosci ; 2020 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-32445072

RESUMO

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by the degeneration of motor neurons. Between 12 and 20% of inherited cases and approximately 1-2% of all cases are caused by mutations in the gene encoding dismutase 1 (SOD1). Mutant SOD1 A4V (alanine to valine) induces endoplasmic reticulum (ER) stress, which is increasingly implicated as a pathway to motor neuron degeneration and death in ALS. However, it remains unclear how ER stress is induced by mutant SOD1 A4V. Previous studies have established that it is induced early in pathophysiology and it precedes the formation of mutant SOD1 inclusions. SOD1 contains four cysteine residues, two of which form an intra-subunit disulphide bond involving Cys-57 and Cys-146. The remaining two cysteines, Cys-6 and Cys-111, remain unpaired and have been implicated in mutant SOD1 aggregation. In this study, we examined the relationship between the SOD1 A4V cysteine residues and aggregation, ER stress induction and toxicity. We report here that mutation of Cys-6 and Cys-111 in mutant SOD1 A4V, but not Cys-57 or Cys-146, ameliorates ER stress, inclusion formation and apoptosis in neuronal cell lines. These results imply that protein misfolding, induced by Cys-6 and Cys-111, is required for these pathological events in neuronal cells.

3.
J Proteome Res ; 2020 May 22.
Artigo em Inglês | MEDLINE | ID: mdl-32407095

RESUMO

We describe a useful workflow for characterizing proteomics experiments incorporating many conditions and abundance data using the popular weighted gene correlation network analysis (WGCNA) approach and functional annotation with the PloGO2 R package, the latter of which we have extended and made available to Bioconductor. The approach can use quantitative data from labeled or label-free experiments and was developed to handle multiple files stemming from data partition or multiple pairwise comparisons. The WGCNA approach can similarly produce a potentially large number of clusters of interest, which can also be functionally characterized using PloGO2. Enrichment analysis will identify clusters or subsets of proteins of interest, and the WGCNA network topology scores will produce a ranking of proteins within these clusters or subsets. This can naturally lead to prioritized proteins to be considered for further analysis or as candidates of interest for validation in the context of complex experiments. We demonstrate the use of the package on two published data sets using two different biological systems (plant and human plasma) and proteomics platforms (sequential window acquisition of all theoretical fragment-ion spectra (SWATH) and tandem mass tag (TMT)): an analysis of the effect of drought on rice over time generated using TMT and a pediatric plasma sample data set generated using SWATH. In both, the automated workflow recapitulates key insights or observations of the published papers and provides additional suggestions for further investigation. These findings indicate that the data set analysis using WGCNA combined with the updated PloGO2 package is a powerful method to gain biological insights from complex multifaceted proteomics experiments.

4.
J Neurol Neurosurg Psychiatry ; 91(2): 162-171, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31690696

RESUMO

OBJECTIVE: Since the first report of CHCHD10 gene mutations in amyotrophiclateral sclerosis (ALS)/frontotemporaldementia (FTD) patients, genetic variation in CHCHD10 has been inconsistently linked to disease. A pathological assessment of the CHCHD10 protein in patient neuronal tissue also remains to be reported. We sought to characterise the genetic and pathological contribution of CHCHD10 to ALS/FTD in Australia. METHODS: Whole-exome and whole-genome sequencing data from 81 familial and 635 sporadic ALS, and 108 sporadic FTD cases, were assessed for genetic variation in CHCHD10. CHCHD10 protein expression was characterised by immunohistochemistry, immunofluorescence and western blotting in control, ALS and/or FTD postmortem tissues and further in a transgenic mouse model of TAR DNA-binding protein 43 (TDP-43) pathology. RESULTS: No causal, novel or disease-associated variants in CHCHD10 were identified in Australian ALS and/or FTD patients. In human brain and spinal cord tissues, CHCHD10 was specifically expressed in neurons. A significant decrease in CHCHD10 protein level was observed in ALS patient spinal cord and FTD patient frontal cortex. In a TDP-43 mouse model with a regulatable nuclear localisation signal (rNLS TDP-43 mouse), CHCHD10 protein levels were unaltered at disease onset and early in disease, but were significantly decreased in cortex in mid-stage disease. CONCLUSIONS: Genetic variation in CHCHD10 is not a common cause of ALS/FTD in Australia. However, we showed that in humans, CHCHD10 may play a neuron-specific role and a loss of CHCHD10 function may be linked to ALS and/or FTD. Our data from the rNLS TDP-43 transgenic mice suggest that a decrease in CHCHD10 levels is a late event in aberrant TDP-43-induced ALS/FTD pathogenesis.

5.
Front Neurosci ; 13: 548, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31244593

RESUMO

Neurodegenerative disorders such as amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are increasing in prevalence but lack targeted therapeutics. Although the pathological mechanisms behind these diseases remain unclear, both ALS and FTD are characterized pathologically by aberrant protein aggregation and inclusion formation within neurons, which correlates with neurodegeneration. Notably, aggregation of several key proteins, including TAR DNA binding protein of 43 kDa (TDP-43), superoxide dismutase 1 (SOD1), and tau, have been implicated in these diseases. Proteomics methods are being increasingly applied to better understand disease-related mechanisms and to identify biomarkers of disease, using model systems as well as human samples. Proteomics-based approaches offer unbiased, high-throughput, and quantitative results with numerous applications for investigating proteins of interest. Here, we review recent advances in the understanding of ALS and FTD pathophysiology obtained using proteomics approaches, and we assess technical and experimental limitations. We compare findings from various mass spectrometry (MS) approaches including quantitative proteomics methods such as stable isotope labeling by amino acids in cell culture (SILAC) and tandem mass tagging (TMT) to approaches such as label-free quantitation (LFQ) and sequential windowed acquisition of all theoretical fragment ion mass spectra (SWATH-MS) in studies of ALS and FTD. Similarly, we describe disease-related protein-protein interaction (PPI) studies using approaches including immunoprecipitation mass spectrometry (IP-MS) and proximity-dependent biotin identification (BioID) and discuss future application of new techniques including proximity-dependent ascorbic acid peroxidase labeling (APEX), and biotinylation by antibody recognition (BAR). Furthermore, we explore the use of MS to detect post-translational modifications (PTMs), such as ubiquitination and phosphorylation, of disease-relevant proteins in ALS and FTD. We also discuss upstream technologies that enable enrichment of proteins of interest, highlighting the contributions of new techniques to isolate disease-relevant protein inclusions including flow cytometric analysis of inclusions and trafficking (FloIT). These recently developed approaches, as well as related advances yet to be applied to studies of these neurodegenerative diseases, offer numerous opportunities for discovery of potential therapeutic targets and biomarkers for ALS and FTD.

6.
Front Neurosci ; 13: 335, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31031584

RESUMO

During neurodegenerative disease, the multifunctional RNA-binding protein TDP-43 undergoes a vast array of post-translational modifications, including phosphorylation, acetylation, and cleavage. Many of these alterations may directly contribute to the pathogenesis of TDP-43 proteinopathies, which include most forms of amyotrophic lateral sclerosis (ALS) and approximately half of all frontotemporal dementia, pathologically identified as frontotemporal lobar degeneration (FTLD) with TDP-43 pathology. However, the relative contributions of the various TDP-43 post-translational modifications to disease remain unclear, and indeed some may be secondary epiphenomena rather than disease-causative. It is therefore critical to determine the involvement of each modification in disease processes to allow the design of targeted treatments. In particular, TDP-43 C-terminal fragments (CTFs) accumulate in the brains of people with ALS and FTLD and are therefore described as a neuropathological signature of these diseases. Remarkably, these TDP-43 CTFs are rarely observed in the spinal cord, even in ALS which involves dramatic degeneration of spinal motor neurons. Therefore, TDP-43 CTFs are not produced non-specifically in the course of all forms of TDP-43-related neurodegeneration, but rather variably arise due to additional factors influenced by regional heterogeneity in the central nervous system. In this review, we summarize how TDP-43 CTFs are generated and degraded by cells, and critique evidence from studies of TDP-43 CTF pathology in human disease tissues, as well as cell and animal models, to analyze the pathophysiological relevance of TDP-43 CTFs to ALS and FTLD. Numerous studies now indicate that, although TDP-43 CTFs are prevalent in ALS and FTLD brains, disease-related pathology is only variably reproduced in TDP-43 CTF cell culture models. Furthermore, TDP-43 CTF expression in both transgenic and viral-mediated in vivo models largely fails to induce motor or behavioral dysfunction reminiscent of human disease. We therefore conclude that although TDP-43 CTFs are a hallmark of TDP-43-related neurodegeneration in the brain, they are not a primary cause of ALS or FTLD.

7.
Psychoneuroendocrinology ; 99: 191-195, 2019 01.
Artigo em Inglês | MEDLINE | ID: mdl-30253326

RESUMO

Signaling through ß-adrenergic receptors drives cancer progression and ß-blockers are being evaluated as a novel therapeutic strategy to prevent metastasis. Orthotopic mouse models of breast cancer show that ß-adrenergic signaling induced by chronic stress accelerates metastasis, and that ß2-adrenergic receptors on tumor cells are critical for this. Endogenous catecholamines are released during chronic stress: norepinephrine from the adrenal medulla and sympathetic nerves, and epinephrine from the adrenal medulla. ß2-adrenergic receptors are much more sensitive to epinephrine than to norepinephrine. To determine if epinephrine is necessary in the effects of stress on cancer progression, we used a denervation strategy to eliminate circulating epinephrine, and quantified the effect on metastasis. Using both human xenograft and immune-intact murine models of breast cancer, we show that circulating epinephrine is dispensable for the effects of chronic stress on cancer progression. Measured levels of circulating norepinephrine were sufficiently low that they were unlikely to influence ß2-adrenergic signaling, suggesting a possible role for norepinephrine release from sympathetic nerve terminals.


Assuntos
Epinefrina/fisiologia , Metástase Neoplásica/fisiopatologia , Estresse Psicológico/metabolismo , Medula Suprarrenal/fisiopatologia , Antagonistas Adrenérgicos beta/farmacologia , Animais , Neoplasias da Mama/fisiopatologia , Modelos Animais de Doenças , Epinefrina/sangue , Epinefrina/farmacologia , Feminino , Camundongos , Camundongos Endogâmicos BALB C , Neoplasias/metabolismo , Neoplasias/fisiopatologia , Norepinefrina/fisiologia , Receptores Adrenérgicos beta , Transdução de Sinais/efeitos dos fármacos , Circulação Esplâncnica , Nervos Esplâncnicos/metabolismo , Sistema Nervoso Simpático
9.
Mol Psychiatry ; 24(10): 1523-1532, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-29988087

RESUMO

Inflammation activates indoleamine 2,3-dioxygenase (IDO) which metabolizes tryptophan into kynurenine. Circulating kynurenine is transported into the brain by the large amino transporter LAT1 at the level of the blood-brain barrier. We hypothesized that administration of leucine that has a high affinity for LAT1 should prevent the entry of kynurenine into the brain and attenuate the formation of neurotoxic kynurenine metabolites. To test whether leucine could prevent inflammation-induced depression-like behavior, mice were treated with lipopolysaccharide (LPS, 0.83 mg/kg IP) or saline and treated with L-leucine (50 mg/kg, IP) or vehicle administered before and 6 h after LPS. Depression-like behavior was measured by increased duration of immobility in the forced swim test and decreased sucrose preference. Leucine decreased brain kynurenine levels, blocked LPS-induced depression-like behavior and had antidepressant-like effects in control mice. Leucine had no effect of its own on sickness behavior and neuroinflammation. To confirm that leucine acts by interfering with the transport of kynurenine into the brain, mice were injected with L-leucine (300 mg/kg, IP) immediately before kynurenine (33 mg/kg IP) and brain kynurenine and depression-like behavior were measured 3 h later. Leucine did prevent the entry of exogenous kynurenine into the brain and abrogated depression-like behavior measured by increased duration of immobility in the forced swim test. Additional experiments using an in vitro model of the blood-brain barrier confirmed that kynurenine competes with leucine at the level of the amino acid transporter LAT1 for brain uptake. These experiments also revealed that efflux was the dominant direction of kynurenine transport and was largely independent of LAT1 and leucine, which explains why leucine could block brain uptake of kynurenine without affecting brain clearance. These findings demonstrate that leucine has antidepressant properties vis-à-vis inflammation-induced depression and one mechanism for this is by blocking the ability of kynurenine to enter the brain.

10.
PLoS One ; 13(12): e0208593, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30532184

RESUMO

Cancer patients with non-central nervous system tumors often suffer from cognitive impairment. While chemotherapy has long been attributed as the cause of these memory, learning and concentration difficulties, we recently observed cognitive impairment in cancer patients prior to treatment. This suggests the cancer alone may be sufficient to induce cognitive impairment, however the mechanisms are unknown. Here, we show that we can experimentally replicate the clinical phenomenon of cancer-associated cognitive impairment and we identify inflammation as a causal mechanism. We demonstrate that a peripheral tumor is sufficient to induce memory loss. Using an othotopic mouse model of breast cancer, we found that mice with 4T1.2 or EO771 mammary tumors had significantly poorer memory than mice without tumors. Memory impairment was independent of cancer-induced sickness behavior, which was only observed during the later stage of cancer progression in mice with high metastatic burden. Tumor-secreted factors were sufficient to induce memory impairment and pro-inflammatory cytokines were elevated in the plasma of tumor-bearing mice. Oral treatment with low-dose aspirin completely blocked tumor-induced memory impairment without affecting tumor-induced sickness or tumor growth, demonstrating a causal role for inflammation in cognitive impairment. These findings suggest that anti-inflammatories may be a safe and readily translatable strategy that could be used to prevent cancer-associated cognitive impairment in patients.


Assuntos
Anti-Inflamatórios não Esteroides/uso terapêutico , Aspirina/uso terapêutico , Disfunção Cognitiva/prevenção & controle , Neoplasias Mamárias Animais/patologia , Animais , Aspirina/farmacologia , Comportamento Animal/efeitos dos fármacos , Citocinas/sangue , Relação Dose-Resposta a Droga , Feminino , Neoplasias Mamárias Animais/complicações , Memória/efeitos dos fármacos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Endogâmicos C57BL
11.
ACS Chem Neurosci ; 9(7): 1616-1624, 2018 07 18.
Artigo em Inglês | MEDLINE | ID: mdl-29708326

RESUMO

Ethanol is a principle ingredient of alcoholic beverages with potential neurotoxicity and genotoxicity, and the ethanol-associated oxidative DNA damage in the central nervous system is well documented. Natural source compounds may offer new options to protect the brain against ethanol-induced genotoxicity. Veratrum maackii Regel is a toxic rangeland plant linked to teratogenicity which is also used in traditional Chinese medicine as "Lilu" and is reported to contain a family of compounds called stilbenes that can have positive biological activity. In this study, nine stilbenes were isolated from the aerial parts of V. maackii Regel, and their structures were identified as cis-mulberroside A (1), resveratrol-4,3'- O-ß-d-diglucopyranoside (2), mulberroside A (3), gentifolin K (4), resveratrol-3,5- O-ß-d-diglucopyranoside (5), oxyresveratrol- 4'- O-ß-d-glucopyranoside (6), oxyresveratrol-3- O-ß-d-glucopyranoside (7), oxyresveratrol (8), and resveratrol (9) using ESI-MS and NMR techniques. The total concentration of extracted compounds 2-9 was 2.04 mg/g, suggesting that V. maackii Regel is a novel viable source of these compounds. In an in vivo comet assay, compounds 1-9 were observed to decrease DNA damage in mouse cerebellum and cerebral cortex caused by acute ethanol administration. Histological observation also revealed decreased brain injury in mice administered with compounds 1-9 after acute ethanol administration. The protective effects of compound 6 were associated with increasing T-SOD and GSH-PX activities and a decrease in NO and MDA concentrations. These findings suggest that these compounds are potent inhibitors of ethanol-induced brain injury possibly via the inhibition of oxidative stress and may be valuable leads for future therapeutic development.


Assuntos
Depressores do Sistema Nervoso Central/efeitos adversos , Dano ao DNA/efeitos dos fármacos , Etanol/efeitos adversos , Substâncias Protetoras/farmacologia , Estilbenos/farmacologia , Veratrum , Transtornos Relacionados ao Uso de Álcool/tratamento farmacológico , Transtornos Relacionados ao Uso de Álcool/metabolismo , Transtornos Relacionados ao Uso de Álcool/patologia , Animais , Cerebelo/efeitos dos fármacos , Cerebelo/metabolismo , Cerebelo/patologia , Córtex Cerebral/efeitos dos fármacos , Córtex Cerebral/metabolismo , Córtex Cerebral/patologia , Masculino , Camundongos , Estrutura Molecular , Neurônios/efeitos dos fármacos , Neurônios/metabolismo , Neurônios/patologia , Fototerapia , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Extratos Vegetais/farmacologia , Substâncias Protetoras/química , Substâncias Protetoras/isolamento & purificação , Distribuição Aleatória , Estilbenos/química , Estilbenos/isolamento & purificação
12.
Hum Mol Genet ; 27(8): 1311-1331, 2018 04 15.
Artigo em Inglês | MEDLINE | ID: mdl-29409023

RESUMO

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder and mutations in superoxide dismutase 1 (SOD1) account for 20% of familial ALS cases. The aetiology of ALS remains unclear, but protein misfolding, endoplasmic reticulum (ER) stress and neuronal apoptosis are implicated. We previously established that protein disulphide isomerase (PDIA1) is protective against ER stress and apoptosis in neuronal cells expressing mutant SOD1, and recently mutations in PDIA1 and related PDI family member endoplasmic reticulum protein 57 (ERp57/PDIA3), were associated with ALS. Here, we examined whether ERp57 is also protective against mutant SOD1 or whether distinct specificity exists amongst individual PDI family members. Neuronal cells co-expressing SOD1 and ERp57 were examined for inclusion formation, ER stress, ubiquitin proteasome system (UPS) dysfunction and apoptosis. Over-expression of ERp57 inhibited inclusion formation, ER stress, UPS dysfunction and apoptosis, whereas silencing of ERp57 expression enhanced mutant SOD1 inclusion formation, ER stress and toxicity, indicating a protective role for ERp57 against SOD1 misfolding. ERp57 also inhibited the formation of mutant SOD1 inclusions and apoptosis in primary cortical neurons, thus confirming results obtained from cell lines. ERp57 partially co-localized with TAR DNA-binding protein-43 (TDP-43)-positive inclusions in spinal cords from sporadic ALS patients, thus linking ERp57 to protein misfolding in human sporadic disease. Our results therefore imply that ERp57 has a protective role against pathological events induced by mutant SOD1 and they link ERp57 to the misfolding of TDP-43. This study therefore has implications for the design of novel therapeutics based on the activities of the PDI family of proteins.


Assuntos
Esclerose Amiotrófica Lateral/genética , Proteínas de Ligação a DNA/genética , Estresse do Retículo Endoplasmático/genética , Neurônios/metabolismo , Isomerases de Dissulfetos de Proteínas/genética , Superóxido Dismutase-1/genética , Idoso , Esclerose Amiotrófica Lateral/metabolismo , Esclerose Amiotrófica Lateral/patologia , Animais , Apoptose , Linhagem Celular , Proteínas de Ligação a DNA/química , Proteínas de Ligação a DNA/metabolismo , Embrião de Mamíferos , Feminino , Regulação da Expressão Gênica , Humanos , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Pessoa de Meia-Idade , Mutação , Neurônios/patologia , Cultura Primária de Células , Isomerases de Dissulfetos de Proteínas/antagonistas & inibidores , Isomerases de Dissulfetos de Proteínas/metabolismo , RNA Interferente Pequeno/genética , RNA Interferente Pequeno/metabolismo , Transdução de Sinais , Medula Espinal/metabolismo , Medula Espinal/patologia , Superóxido Dismutase-1/metabolismo
13.
Oncology (Williston Park) ; 32(12): 591-8, 2018 12 17.
Artigo em Inglês | MEDLINE | ID: mdl-30632128

RESUMO

Up to 70% of survivors of adult-onset, non-central nervous system (CNS) solid tumors report cognitive symptoms, and approximately 30% have impairment on formal neuropsychological testing. The etiology of the impairment is unknown. There is a lack of robust evidence on how to prevent or treat cancer-related cognitive impairment (CRCI). Here, we review the evidence for the putative mechanisms of CRCI by examining clinical and preclinical models, primarily those associated with chemotherapy. Pharmacologic and nonpharmacologic options for treating CRCI are discussed based on the best evidence available. Practical clinical advice for health professionals managing patients with CRCI is also provided.


Assuntos
Antineoplásicos/efeitos adversos , Disfunção Cognitiva/etiologia , Disfunção Cognitiva/terapia , Neoplasias/complicações , Humanos , Neoplasias/psicologia , Sobreviventes
14.
Cell Mol Life Sci ; 75(2): 335-354, 2018 01.
Artigo em Inglês | MEDLINE | ID: mdl-28852778

RESUMO

Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are fatal neurodegenerative disorders that have common molecular and pathogenic characteristics, such as aberrant accumulation and ubiquitylation of TDP-43; however, the mechanisms that drive this process remain poorly understood. We have recently identified CCNF mutations in familial and sporadic ALS and FTD patients. CCNF encodes cyclin F, a component of an E3 ubiquitin-protein ligase (SCFcyclin F) complex that is responsible for ubiquitylating proteins for degradation by the ubiquitin-proteasome system. In this study, we examined the ALS/FTD-causing p.Ser621Gly (p.S621G) mutation in cyclin F and its effect upon downstream Lys48-specific ubiquitylation in transfected Neuro-2A and SH-SY5Y cells. Expression of mutant cyclin FS621G caused increased Lys48-specific ubiquitylation of proteins in neuronal cells compared to cyclin FWT. Proteomic analysis of immunoprecipitated Lys48-ubiquitylated proteins from mutant cyclin FS621G-expressing cells identified proteins that clustered within the autophagy pathway, including sequestosome-1 (p62/SQSTM1), heat shock proteins, and chaperonin complex components. Examination of autophagy markers p62, LC3, and lysosome-associated membrane protein 2 (Lamp2) in cells expressing mutant cyclin FS621G revealed defects in the autophagy pathway specifically resulting in impairment in autophagosomal-lysosome fusion. This finding highlights a potential mechanism by which cyclin F interacts with p62, the receptor responsible for transporting ubiquitylated substrates for autophagic degradation. These findings demonstrate that ALS/FTD-causing mutant cyclin FS621G disrupts Lys48-specific ubiquitylation, leading to accumulation of substrates and defects in the autophagic machinery. This study also demonstrates that a single missense mutation in cyclin F causes hyper-ubiquitylation of proteins that can indirectly impair the autophagy degradation pathway, which is implicated in ALS pathogenesis.


Assuntos
Esclerose Amiotrófica Lateral/genética , Autofagia/genética , Ciclinas/genética , Demência Frontotemporal/genética , Ubiquitinação/genética , Esclerose Amiotrófica Lateral/complicações , Células Cultivadas , Demência Frontotemporal/complicações , Células HEK293 , Humanos , Lisina/metabolismo , Mutação de Sentido Incorreto/fisiologia
15.
Open Biol ; 7(10)2017 10.
Artigo em Inglês | MEDLINE | ID: mdl-29021214

RESUMO

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disorder that is characterized by progressive weakness, paralysis and muscle loss often resulting in patient death within 3-5 years of diagnosis. Recently, we identified disease-linked mutations in the CCNF gene, which encodes the cyclin F protein, in cohorts of patients with familial and sporadic ALS and frontotemporal dementia (FTD) (Williams KL et al 2016 Nat. Commun.7, 11253. (doi:10.1038/ncomms11253)). Cyclin F is a part of a Skp1-Cul-F-box (SCF) E3 ubiquitin-protein ligase complex and is responsible for ubiquitylating proteins for degradation by the proteasome. In this study, we investigated the phosphorylation status of cyclin F and the effect of the serine to glycine substitution at site 621 (S621G) on E3 ligase activity. This specific mutation (S621G) was found in a multi-generational Australian family with ALS/FTD. We identified seven phosphorylation sites on cyclin F, of which five are newly reported including Ser621. These phosphorylation sites were mostly identified within the PEST (proline, glutamic acid, serine and threonine) sequence located at the C-terminus of cyclin F. Additionally, we determined that casein kinase II (CK2) can phosphorylate Ser621 and thereby regulate the E3 ligase activity of the SCF(cyclin F) complex. Furthermore, the S621G mutation in cyclin F prevents phosphorylation by CK2 and confers elevated Lys48-ubiquitylation activity, a hallmark of ALS/FTD pathology. These findings highlight the importance of phosphorylation in regulating the activity of the SCF(cyclin F) E3 ligase complex that can affect downstream processes and may lead to defective motor neuron development, neuron degeneration and ultimately ALS and FTD.


Assuntos
Caseína Quinase II/metabolismo , Ciclinas/metabolismo , Complexos Multiproteicos/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , Linhagem Celular Tumoral , Cromatografia Líquida , Ativação Enzimática , Células HEK293 , Humanos , Lisina , Espectrometria de Massas , Modelos Moleculares , Fosfatidilserinas , Fosforilação , Ligação Proteica , Ubiquitinação
17.
Front Mol Neurosci ; 10: 119, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-28539871

RESUMO

Protein homeostasis, or proteostasis, has an important regulatory role in cellular function. Protein quality control mechanisms, including protein folding and protein degradation processes, have a crucial function in post-mitotic neurons. Cellular protein quality control relies on multiple strategies, including molecular chaperones, autophagy, the ubiquitin proteasome system, endoplasmic reticulum (ER)-associated degradation (ERAD) and the formation of stress granules (SGs), to regulate proteostasis. Neurodegenerative diseases are characterized by the presence of misfolded protein aggregates, implying that protein quality control mechanisms are dysfunctional in these conditions. Amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD) are neurodegenerative diseases that are now recognized to overlap clinically and pathologically, forming a continuous disease spectrum. In this review article, we detail the evidence for dysregulation of protein quality control mechanisms across the whole ALS-FTD continuum, by discussing the major proteins implicated in ALS and/or FTD. We also discuss possible ways in which protein quality mechanisms could be targeted therapeutically in these disorders and highlight promising protein quality control-based therapeutics for clinical trials.

18.
Metabolites ; 6(4)2016 Sep 22.
Artigo em Inglês | MEDLINE | ID: mdl-27669323

RESUMO

Cancer cells often have dysregulated metabolism, which is largely characterized by the Warburg effect-an increase in glycolytic activity at the expense of oxidative phosphorylation-and increased glutamine utilization. Modern metabolomics tools offer an efficient means to investigate metabolism in cancer cells. Currently, a number of protocols have been described for harvesting adherent cells for metabolomics analysis, but the techniques vary greatly and they lack specificity to particular cancer cell lines with diverse metabolic and structural features. Here we present an optimized method for untargeted metabolomics characterization of MDA-MB-231 triple negative breast cancer cells, which are commonly used to study metastatic breast cancer. We found that an approach that extracted all metabolites in a single step within the culture dish optimally detected both polar and non-polar metabolite classes with higher relative abundance than methods that involved removal of cells from the dish. We show that this method is highly suited to diverse applications, including the characterization of central metabolic flux by stable isotope labelling and differential analysis of cells subjected to specific pharmacological interventions.

19.
Brain Behav Immun ; 57: 106-115, 2016 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-27321906

RESUMO

Chronic stress accelerates metastasis - the main cause of death in cancer patients - through the activation of ß-adrenoceptors (ßARs). We have previously shown that ß2AR signaling in MDA-MB-231(HM) breast cancer cells, facilitates invadopodia formation and invasion in vitro. However, in the tumor microenvironment where many stromal cells also express ßAR, the role of ß2AR signaling in tumor cells in metastasis is unclear. Therefore, to investigate the contribution of ß2AR signaling in tumor cells to metastasis in vivo, we used RNA interference to generate MDA-MB-231(HM) breast cancer cells that are deficient in ß2AR. ß2AR knockdown in tumor cells reduced the proportion of cells with a mesenchymal-like morphology and, as expected, reduced tumor cell invasion in vitro. Conversely, overexpression of ß2AR in low metastatic MCF-7 breast cancer cells induced an invasive phenotype. Importantly, we found that knockdown of ß2AR in tumor cells significantly reduced the impact of stress on metastasis in vivo. These findings highlight a crucial role for ß2AR tumor cell signaling in the adverse effects of stress on metastasis, and indicate that it may be necessary to block ß2AR on tumor cells to fully control metastatic progression.


Assuntos
Neoplasias da Mama/metabolismo , Linhagem Celular Tumoral/metabolismo , Metástase Neoplásica , Receptores Adrenérgicos beta 2/metabolismo , Estresse Psicológico/metabolismo , Animais , Modelos Animais de Doenças , Feminino , Expressão Gênica , Humanos , Camundongos , Camundongos Endogâmicos BALB C , Camundongos Transgênicos
20.
Behav Brain Res ; 297: 241-50, 2016 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-26475509

RESUMO

The present study was undertaken to explore the possible mechanisms of the behavioral alterations that develop in response to cancer and to cancer therapy. For this purpose we used a syngeneic heterotopic mouse model of human papilloma virus (HPV)-related head and neck cancer in which cancer therapy is curative. Mice implanted or not with HPV+ tumor cells were exposed to sham treatment or a regimen of cisplatin and radiotherapy (chemoradiation). Sickness was measured by body weight loss and reduced food intake. Motivation was measured by burrowing, a highly prevalent species specific behavior. Tumor-bearing mice showed a gradual decrease in burrowing over time and increased brain and liver inflammatory cytokine mRNA expression by 28 days post tumor implantation. Chemoradiation administered to healthy mice resulted in a mild decrease in burrowing, body weight, and food intake. Chemoradiation in tumor-bearing mice decreased tumor growth and abrogated liver and brain inflammation, but failed to attenuate burrowing deficits. PCR array analysis of selected hypoxia and mitochondrial genes revealed that both the tumor and chemoradiation altered the expression of genes involved in mitochondrial energy metabolism within the liver and brain and increased expression of genes related to HIF-1α signaling within the brain. The most prominent changes in brain mitochondrial genes were noted in tumor-bearing mice treated with chemoradiation. These findings indicate that targeting mitochondrial dysfunction following cancer and cancer therapy may be a strategy for prevention of cancer-related symptoms.


Assuntos
Antineoplásicos/farmacologia , Cisplatino/farmacologia , Genes Mitocondriais , Neoplasias de Cabeça e Pescoço/terapia , Comportamento de Doença/efeitos dos fármacos , Comportamento de Doença/efeitos da radiação , Animais , Encéfalo/efeitos dos fármacos , Encéfalo/imunologia , Encéfalo/patologia , Encéfalo/efeitos da radiação , Quimiorradioterapia , Citocinas/metabolismo , Expressão Gênica/efeitos dos fármacos , Expressão Gênica/efeitos da radiação , Genes Mitocondriais/efeitos dos fármacos , Genes Mitocondriais/efeitos da radiação , Neoplasias de Cabeça e Pescoço/genética , Neoplasias de Cabeça e Pescoço/patologia , Neoplasias de Cabeça e Pescoço/fisiopatologia , Comportamento de Doença/fisiologia , Fígado/efeitos dos fármacos , Fígado/imunologia , Fígado/patologia , Fígado/efeitos da radiação , Masculino , Camundongos Endogâmicos C57BL , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , Mitocôndrias/efeitos da radiação , Motivação/efeitos dos fármacos , Motivação/fisiologia , Motivação/efeitos da radiação , Atividade Motora/efeitos dos fármacos , Atividade Motora/fisiologia , Atividade Motora/efeitos da radiação , Transplante de Neoplasias , Neoplasias Orofaríngeas/genética , Neoplasias Orofaríngeas/patologia , Neoplasias Orofaríngeas/fisiopatologia , Neoplasias Orofaríngeas/terapia , Papillomaviridae , Radiossensibilizantes/farmacologia
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