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1.
Neurobiol Dis ; 170: 105753, 2022 08.
Artigo em Inglês | MEDLINE | ID: mdl-35569719

RESUMO

Under physiological conditions in vivo astrocytes internalize and degrade neuronal mitochondria in a process called transmitophagy. Mitophagy is widely reported to be impaired in neurodegeneration but it is unknown whether and how transmitophagy is altered in Alzheimer's disease (AD). Here we report that the internalization of neuronal mitochondria is significantly increased in astrocytes isolated from AD mouse brains. We also demonstrate that the degradation of neuronal mitochondria by astrocytes is increased in AD mice at the age of 6 months onwards. Furthermore, we demonstrate for the first time a similar phenomenon between human neurons and AD astrocytes, and in murine hippocampi in vivo. The results suggest the involvement of S100a4 in impaired mitochondrial transfer between neurons and AD astrocytes together with significant increases in the mitophagy regulator and reactive oxygen species in aged AD astrocytes. These findings demonstrate altered neuron-supporting functions of AD astrocytes and provide a starting point for studying the molecular mechanisms of transmitophagy in AD.


Assuntos
Doença de Alzheimer , Doença de Alzheimer/metabolismo , Peptídeos beta-Amiloides/metabolismo , Animais , Astrócitos/metabolismo , Camundongos , Mitofagia , Neurônios/metabolismo
2.
Bioorg Med Chem Lett ; 64: 128677, 2022 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-35301136

RESUMO

Preventing the aggregation of certain amyloid proteins has the potential to slow down the progression of diseases like Alzheimer's, Parkinson's, and type 2 diabetes mellitus. During a high-throughput screen of 300 Australian marine invertebrate extracts, the extract of the marine sponge Thorectandra sp. 4408 displayed binding activity to the Parkinson's disease-associated protein, α-synuclein. Isolation of the active component led to its identification as the known plant growth promoter asterubine (1). This molecule shares distinct structural similarities with potent amyloid beta aggregation inhibitors tramiprosate (homotaurine) and ALZ-801. Herein we report the isolation, NMR data acquired in DMSO and α-synuclein binding activity of asterubine (1).


Assuntos
Diabetes Mellitus Tipo 2 , Doença de Parkinson , Amiloide/metabolismo , Peptídeos beta-Amiloides/metabolismo , Austrália , Humanos , Doença de Parkinson/metabolismo , alfa-Sinucleína
3.
J Nat Prod ; 85(2): 441-452, 2022 02 25.
Artigo em Inglês | MEDLINE | ID: mdl-35050597

RESUMO

Seven new polyaromatic bis-spiroketal-containing butenolides, the prunolides D-I (4-9) and cis-prunolide C (10), a new dibrominated ß-carboline sulfamate named pityriacitrin C (11), alongside the known prunolides A-C (1-3) were isolated from the Australian colonial ascidian Synoicum prunum. The prunolides D-G (4-7) represent the first asymmetrically brominated prunolides, while cis-prunolide C (10) is the first reported with a cis-configuration about the prunolide's bis-spiroketal core. The prunolides displayed binding activities with the Parkinson's disease-implicated amyloid protein α-synuclein in a mass spectrometry binding assay, while the prunolides (1-5 and 10) were found to significantly inhibit the aggregation (>89.0%) of α-synuclein in a ThT amyloid dye assay. The prunolides A-C (1-3) were also tested for inhibition of pSyn aggregate formation in a primary embryonic mouse midbrain dopamine neuron model with prunolide B (2) displaying statistically significant inhibitory activity at 0.5 µM. The antiplasmodial and antibacterial activities of the isolates were also examined with prunolide C (3) displaying only weak activity against the 3D7 parasite strain of Plasmodium falciparum. Our findings reported herein suggest that the prunolides could provide a novel scaffold for the exploration of future therapeutics aimed at inhibiting amyloid protein aggregation and the treatment of numerous neurodegenerative diseases.


Assuntos
Urocordados , alfa-Sinucleína , Animais , Austrália , Carbolinas , Camundongos , Ácidos Sulfônicos , Urocordados/química
4.
Mol Ther ; 29(9): 2821-2840, 2021 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-33940158

RESUMO

A molecular hallmark in Parkinson's disease (PD) pathogenesis are α-synuclein aggregates. Cerebral dopamine neurotrophic factor (CDNF) is an atypical growth factor that is mostly resident in the endoplasmic reticulum but exerts its effects both intracellularly and extracellularly. One of the beneficial effects of CDNF can be protecting neurons from the toxic effects of α-synuclein. Here, we investigated the effects of CDNF on α-synuclein aggregation in vitro and in vivo. We found that CDNF directly interacts with α-synuclein with a KD = 23 ± 6 nM and reduces its auto-association. Using nuclear magnetic resonance (NMR) spectroscopy, we identified interaction sites on the CDNF protein. Remarkably, CDNF reduces the neuronal internalization of α-synuclein fibrils and induces the formation of insoluble phosphorylated α-synuclein inclusions. Intra-striatal CDNF administration alleviates motor deficits in rodents challenged with α-synuclein fibrils, though it did not reduce the number of phosphorylated α-synuclein inclusions in the substantia nigra. CDNF's beneficial effects on rodent behavior appear not to be related to the number of inclusions formed in the current context, and further study of its effects on the aggregation mechanism in vivo are needed. Nonetheless, the interaction of CDNF with α-synuclein, modifying its aggregation, spreading, and associated behavioral alterations, provides novel insights into the potential of CDNF as a therapeutic strategy in PD and other synucleinopathies.


Assuntos
Fatores de Crescimento Neural/química , Fatores de Crescimento Neural/metabolismo , Doença de Parkinson/fisiopatologia , Substância Negra/metabolismo , alfa-Sinucleína/química , alfa-Sinucleína/metabolismo , Animais , Sítios de Ligação , Linhagem Celular , Modelos Animais de Doenças , Dopamina/metabolismo , Humanos , Espectroscopia de Ressonância Magnética , Masculino , Camundongos , Modelos Moleculares , Doença de Parkinson/metabolismo , Fosforilação , Cultura Primária de Células , Agregados Proteicos , Ligação Proteica , Conformação Proteica , Ratos
5.
Int J Mol Sci ; 22(18)2021 Sep 07.
Artigo em Inglês | MEDLINE | ID: mdl-34575854

RESUMO

Mesencephalic astrocyte derived neurotrophic factor (MANF) and cerebral dopamine neurotrophic factor (CDNF) are novel evolutionary conserved trophic factors, which exhibit cytoprotective activity via negative regulation of unfolded protein response (UPR) and inflammation. Despite multiple reports demonstrating detrimental effect of MANF/CDNF downregulation, little is known about the control of their expression. miRNAs-small non-coding RNAs-are important regulators of gene expression. Their dysregulation was demonstrated in multiple pathological processes and their ability to modulate levels of other neurotrophic factors, glial cell line-derived neurotrophic factor (GDNF) and brain-derived neurotrophic factor (BDNF), was previously reported. Here, for the first time we demonstrated direct regulation of MANF and CDNF by miRNAs. Using bioinformatic tools, reporter assay and analysis of endogenous MANF and CDNF, we identified that miR-144 controls MANF expression, and miR-134 and miR-141 downregulate CDNF levels. We also demonstrated that this effect is human-specific and is executed via predicted binding sites of corresponding miRNAs. Finally, we found that miR-382 suppressed hCDNF expression indirectly. In conclusion, we demonstrate for the first time direct regulation of MANF and CDNF expression by specific miRNAs, despite the fact their binding sites are not strongly evolutionary conserved. Furthermore, we demonstrate a functional effect of miR-144 mediated regulation of MANF on ER stress response markers. These findings emphasize that (1) prediction of miRNA targets based on evolutionary conservation may miss biologically meaningful regulatory pairs; and (2) interpretation of miRNA regulatory effects in animal models should be cautiously validated.


Assuntos
Regulação da Expressão Gênica , MicroRNAs/genética , Fatores de Crescimento Neural/genética , Interferência de RNA , Regiões 3' não Traduzidas , Linhagem Celular , Estresse do Retículo Endoplasmático , Humanos , RNA Mensageiro/genética
6.
Mov Disord ; 35(12): 2279-2289, 2020 12.
Artigo em Inglês | MEDLINE | ID: mdl-32964492

RESUMO

BACKGROUND: Parkinson's disease (PD) is associated with proteostasis disturbances and accumulation of misfolded α-synuclein (α-syn), a cytosolic protein present in high concentrations at pre-synaptic neuronal terminals. It is a primary constituent of intracellular protein aggregates known as Lewy neurites or Lewy bodies. Progression of Lewy pathology caused by the prion-like self-templating properties of misfolded α-syn is a characteristic feature in the brains of PD patients. Glial cell line-derived neurotrophic factor (GDNF) promotes survival of mature dopamine (DA) neurons in vitro and in vivo. However, the data on its effect on Lewy pathology is controversial. OBJECTIVES: We studied the effects of GDNF on misfolded α-syn accumulation in DA neurons. METHODS: Lewy pathology progression was modeled by the application of α-syn preformed fibrils in cultured DA neurons and in the adult mice. RESULTS: We discovered that GDNF prevented accumulation of misfolded α-syn in DA neurons in culture and in vivo. These effects were abolished by deletion of receptor tyrosine kinase rearranged during transfection (RET) or by inhibitors of corresponding signaling pathway. Expression of constitutively active RET protected DA neurons from fibril-induced α-syn accumulation. CONCLUSIONS: For the first time, we have shown the neurotrophic factor-mediated protection against the misfolded α-syn propagation in DA neurons, uncovered underlying receptors, and investigated the involved signaling pathways. These results demonstrate that activation of GDNF/RET signaling can be an effective therapeutic approach to prevent Lewy pathology spread at early stages of PD. © 2020 International Parkinson and Movement Disorder Society.


Assuntos
Neurônios Dopaminérgicos , Corpos de Lewy , Animais , Neurônios Dopaminérgicos/metabolismo , Fator Neurotrófico Derivado de Linhagem de Célula Glial , Humanos , Corpos de Lewy/metabolismo , Mesencéfalo/metabolismo , Camundongos , Proteínas Proto-Oncogênicas c-ret , Transdução de Sinais , alfa-Sinucleína/metabolismo
7.
Mov Disord ; 35(2): 245-255, 2020 02.
Artigo em Inglês | MEDLINE | ID: mdl-31840869

RESUMO

BACKGROUND: Motor symptoms of Parkinson's disease (PD) are caused by degeneration and progressive loss of nigrostriatal dopamine neurons. Currently, no cure for this disease is available. Existing drugs alleviate PD symptoms but fail to halt neurodegeneration. Glial cell line-derived neurotrophic factor (GDNF) is able to protect and repair dopamine neurons in vitro and in animal models of PD, but the clinical use of GDNF is complicated by its pharmacokinetic properties. The present study aimed to evaluate the neuronal effects of a blood-brain-barrier penetrating small molecule GDNF receptor Rearranged in Transfection agonist, BT13, in the dopamine system. METHODS: We characterized the ability of BT13 to activate RET in immortalized cells, to support the survival of cultured dopamine neurons, to protect cultured dopamine neurons against neurotoxin-induced cell death, to activate intracellular signaling pathways both in vitro and in vivo, and to regulate dopamine release in the mouse striatum as well as BT13's distribution in the brain. RESULTS: BT13 potently activates RET and downstream signaling cascades such as Extracellular Signal Regulated Kinase and AKT in immortalized cells. It supports the survival of cultured dopamine neurons from wild-type but not from RET-knockout mice. BT13 protects cultured dopamine neurons from 6-Hydroxydopamine (6-OHDA) and 1-methyl-4-phenylpyridinium (MPP+ )-induced cell death only if they express RET. In addition, BT13 is absorbed in the brain, activates intracellular signaling cascades in dopamine neurons both in vitro and in vivo, and also stimulates the release of dopamine in the mouse striatum. CONCLUSION: The GDNF receptor RET agonist BT13 demonstrates the potential for further development of novel disease-modifying treatments against PD. © 2019 International Parkinson and Movement Disorder Society.


Assuntos
Neurônios Dopaminérgicos/metabolismo , Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Doença de Parkinson/metabolismo , Substância Negra/metabolismo , Animais , Corpo Estriado/efeitos dos fármacos , Corpo Estriado/metabolismo , Dopamina/metabolismo , Dopamina/farmacologia , Neurônios Dopaminérgicos/efeitos dos fármacos , Receptores de Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Camundongos , Oxidopamina/farmacologia , Doença de Parkinson Secundária/induzido quimicamente , Substância Negra/efeitos dos fármacos
8.
J Neurosci Res ; 97(3): 346-361, 2019 03.
Artigo em Inglês | MEDLINE | ID: mdl-30548446

RESUMO

Adeno-associated virus (AAV) vector-mediated delivery of human α-synuclein (α-syn) gene in rat substantia nigra (SN) results in increased expression of α-syn protein in the SN and striatum which can progressively degenerate dopaminergic neurons. Therefore, this model is thought to recapitulate the neurodegeneration in Parkinson's disease. Here, using AAV to deliver α-syn above the SN in male and female rats resulted in clear expression of human α-syn in the SN and striatum. The protein was associated with moderate behavioral deficits and some loss of tyrosine hydroxylase (TH) in the nigrostriatal areas. However, the immunohistochemistry results were highly variable and showed little to no correlation with behavior and the amount of α-syn present. Expression of green fluorescent protein (GFP) was used as a control to monitor gene delivery and expression efficacy. AAV-GFP resulted in a similar or greater TH loss compared to AAV-α-syn and therefore an additional vector that does not express a protein was tested. Vectors with double-floxed inverse open reading frame (DIO ORF) encoding fluorescent proteins that generate RNA that is not translated also resulted in TH downregulation in the SN but showed no significant behavioral deficits. These results demonstrate that although expression of wild-type human α-syn can cause neurodegeneration, the variability and lack of correlation with outcome measures are drawbacks with the model. Furthermore, design and control selection should be considered carefully because of conflicting conclusions due to AAV downregulation of TH, and we recommend caution with having highly regulated TH as the only marker for the dopamine system.


Assuntos
Substância Negra/metabolismo , Tirosina 3-Mono-Oxigenase/metabolismo , alfa-Sinucleína/metabolismo , Animais , Dependovirus , Dopamina/metabolismo , Regulação para Baixo , Feminino , Humanos , Masculino , Modelos Animais , Doença de Parkinson/metabolismo , Ratos , Ratos Sprague-Dawley , Ratos Wistar
9.
Mol Ther ; 26(1): 238-255, 2018 01 03.
Artigo em Inglês | MEDLINE | ID: mdl-29050872

RESUMO

Cerebral ischemia activates endogenous reparative processes, such as increased proliferation of neural stem cells (NSCs) in the subventricular zone (SVZ) and migration of neural progenitor cells (NPCs) toward the ischemic area. However, this reparative process is limited because most of the NPCs die shortly after injury or are unable to arrive at the infarct boundary. In this study, we demonstrate for the first time that endogenous mesencephalic astrocyte-derived neurotrophic factor (MANF) protects NSCs against oxygen-glucose-deprivation-induced injury and has a crucial role in regulating NPC migration. In NSC cultures, MANF protein administration did not affect growth of cells but triggered neuronal and glial differentiation, followed by activation of STAT3. In SVZ explants, MANF overexpression facilitated cell migration and activated the STAT3 and ERK1/2 pathway. Using a rat model of cortical stroke, intracerebroventricular injections of MANF did not affect cell proliferation in the SVZ, but promoted migration of doublecortin (DCX)+ cells toward the corpus callosum and infarct boundary on day 14 post-stroke. Long-term infusion of MANF into the peri-infarct zone increased the recruitment of DCX+ cells in the infarct area. In conclusion, our data demonstrate a neuroregenerative activity of MANF that facilitates differentiation and migration of NPCs, thereby increasing recruitment of neuroblasts in stroke cortex.


Assuntos
Diferenciação Celular/genética , Fatores de Crescimento Neural/genética , Regeneração Nervosa/genética , Células-Tronco Neurais/citologia , Células-Tronco Neurais/metabolismo , Acidente Vascular Cerebral/genética , Animais , Astrócitos/citologia , Astrócitos/metabolismo , Encéfalo/metabolismo , Encéfalo/patologia , Morte Celular , Autorrenovação Celular/genética , Células Cultivadas , Modelos Animais de Doenças , Proteína Duplacortina , Imunofluorescência , Expressão Gênica , Imuno-Histoquímica , Camundongos , Camundongos Knockout , Neuroglia/citologia , Neuroglia/metabolismo , Neurônios/citologia , Neurônios/metabolismo , Fator de Transcrição STAT3/metabolismo , Estresse Fisiológico , Acidente Vascular Cerebral/metabolismo , Acidente Vascular Cerebral/patologia
10.
Int J Mol Sci ; 20(23)2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31801298

RESUMO

MicroRNAs are post-transcriptional regulators of gene expression, crucial for neuronal differentiation, survival, and activity. Age-related dysregulation of microRNA biogenesis increases neuronal vulnerability to cellular stress and may contribute to the development and progression of neurodegenerative diseases. All major neurodegenerative disorders are also associated with oxidative stress, which is widely recognized as a potential target for protective therapies. Albeit often considered separately, microRNA networks and oxidative stress are inextricably entwined in neurodegenerative processes. Oxidative stress affects expression levels of multiple microRNAs and, conversely, microRNAs regulate many genes involved in an oxidative stress response. Both oxidative stress and microRNA regulatory networks also influence other processes linked to neurodegeneration, such as mitochondrial dysfunction, deregulation of proteostasis, and increased neuroinflammation, which ultimately lead to neuronal death. Modulating the levels of a relatively small number of microRNAs may therefore alleviate pathological oxidative damage and have neuroprotective activity. Here, we review the role of individual microRNAs in oxidative stress and related pathways in four neurodegenerative conditions: Alzheimer's (AD), Parkinson's (PD), Huntington's (HD) disease, and amyotrophic lateral sclerosis (ALS). We also discuss the problems associated with the use of oversimplified cellular models and highlight perspectives of studying microRNA regulation and oxidative stress in human stem cell-derived neurons.


Assuntos
Doença de Alzheimer/metabolismo , Esclerose Lateral Amiotrófica/metabolismo , Doença de Huntington/metabolismo , MicroRNAs/genética , Estresse Oxidativo/genética , Doença de Parkinson/metabolismo , Doença de Alzheimer/genética , Doença de Alzheimer/patologia , Peptídeos beta-Amiloides/química , Peptídeos beta-Amiloides/genética , Peptídeos beta-Amiloides/metabolismo , Esclerose Lateral Amiotrófica/genética , Esclerose Lateral Amiotrófica/patologia , Animais , Regulação da Expressão Gênica , Humanos , Doença de Huntington/genética , Doença de Huntington/patologia , MicroRNAs/classificação , MicroRNAs/metabolismo , Mitocôndrias/metabolismo , Proteínas do Tecido Nervoso/classificação , Proteínas do Tecido Nervoso/genética , Proteínas do Tecido Nervoso/metabolismo , Neurônios/metabolismo , Neurônios/patologia , Oxirredução , Doença de Parkinson/genética , Doença de Parkinson/patologia , Transdução de Sinais
11.
J Biol Chem ; 292(36): 14977-14988, 2017 09 08.
Artigo em Inglês | MEDLINE | ID: mdl-28698383

RESUMO

Cytokine-induced endoplasmic reticulum (ER) stress is one of the molecular mechanisms underlying pancreatic ß-cell demise in type 1 diabetes. Thrombospondin 1 (THBS1) was recently shown to promote ß-cell survival during lipotoxic stress. Here we show that ER-localized THBS1 is cytoprotective to rat, mouse, and human ß-cells exposed to cytokines or thapsigargin-induced ER stress. THBS1 confers cytoprotection by maintaining expression of mesencephalic astrocyte-derived neutrotrophic factor (MANF) in ß-cells and thereby prevents the BH3-only protein BIM (BCL2-interacting mediator of cell death)-dependent triggering of the mitochondrial pathway of apoptosis. Prolonged exposure of ß-cells to cytokines or thapsigargin leads to THBS1 and MANF degradation and loss of this prosurvival mechanism. Approaches that sustain intracellular THBS1 and MANF expression in ß-cells should be explored as a cytoprotective strategy in type 1 diabetes.


Assuntos
Inflamação/metabolismo , Células Secretoras de Insulina/metabolismo , Fatores de Crescimento Neural/metabolismo , Trombospondina 1/metabolismo , Animais , Células Cultivadas , Citocinas/metabolismo , Retículo Endoplasmático/metabolismo , Humanos , Células Secretoras de Insulina/efeitos dos fármacos , Camundongos , Fatores de Crescimento Neural/antagonistas & inibidores , Estresse Oxidativo , Tapsigargina/farmacologia
12.
Neurobiol Dis ; 97(Pt B): 189-200, 2017 01.
Artigo em Inglês | MEDLINE | ID: mdl-27189755

RESUMO

Drug addiction is a chronic brain disease and drugs of abuse cause long lasting neuroadaptations. Addiction is characterized by the loss of control over drug use despite harmful consequences, and high rates of relapse even after long periods of abstinence. Neurotrophic factors (NTFs) are well known for their actions on neuronal survival in the peripheral nervous system. Moreover, NTFs have been shown to be involved in synaptic plasticity in the brain. Brain-derived neurotrophic factor (BDNF) and glial cell line-derived neurotrophic factor (GDNF) are two of the most studied NTFs and both of them have been reported to increase craving when administered into the mesocorticolimbic dopaminergic system after drug self-administration. Here we review recent data on BDNF and GDNF functions in addiction-related behavior and discuss them in relation to previous findings. Finally, we give an insight into how new technologies could aid in further elucidating the role of these factors in drug addiction.


Assuntos
Fatores de Crescimento Neural/metabolismo , Transtornos Relacionados ao Uso de Substâncias/metabolismo , Animais , Humanos
13.
J Neurosci ; 31(2): 453-60, 2011 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-21228155

RESUMO

The nucleolus represents an essential stress sensor for the cell. However, the molecular consequences of nucleolar damage and their possible link with neurodegenerative diseases remain to be elucidated. Here, we show that nucleolar damage is present in both genders in Parkinson's disease (PD) and in the pharmacological PD model induced by the neurotoxin 1,2,3,6-tetrahydro-1-methyl-4-phenylpyridine hydrochloride (MPTP). Mouse mutants with nucleolar disruption restricted to dopaminergic (DA) neurons show phenotypic alterations that resemble PD, such as progressive and differential loss of DA neurons and locomotor abnormalities. At the molecular level, nucleolar disruption results in increased p53 levels and downregulation of mammalian target of rapamycin (mTOR) activity, leading to mitochondrial dysfunction and increased oxidative stress, similar to PD. In turn, increased oxidative stress induced by MPTP causes mTOR and ribosomal RNA synthesis inhibition. Collectively, these observations suggest that the interplay between nucleolar dysfunction and increased oxidative stress, involving p53 and mTOR signaling, may constitute a destructive axis in experimental and sporadic PD.


Assuntos
Nucléolo Celular/patologia , Dopamina/metabolismo , Neurônios/patologia , Estresse Oxidativo , Transtornos Parkinsonianos/metabolismo , Transtornos Parkinsonianos/patologia , Serina-Treonina Quinases TOR/fisiologia , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina , Animais , Encéfalo/metabolismo , Encéfalo/patologia , Nucléolo Celular/metabolismo , Deleção de Genes , Humanos , Camundongos , Camundongos Endogâmicos C57BL , Camundongos Mutantes , Camundongos Transgênicos , Mitocôndrias/fisiologia , Destreza Motora , Neurônios/metabolismo , Doença de Parkinson/patologia , Transtornos Parkinsonianos/fisiopatologia , Proteínas Pol1 do Complexo de Iniciação de Transcrição/genética , Transdução de Sinais , Proteína Supressora de Tumor p53/fisiologia
14.
FASEB J ; 25(9): 2898-910, 2011 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-21593433

RESUMO

Parkinson's disease (PD) is a progressive age-related movement disorder that results primarily from the selective loss of midbrain dopaminergic (DA) neurons. Symptoms of PD can be induced by genetic mutations or by DA neuron-specific toxins. A specific ablation of an essential factor controlling ribosomal RNA transcription, TifIa, in adult mouse DA neurons represses mTOR signaling and leads to progressive neurodegeneration and PD-like phenotype. Using an inducible Cre system in adult mice, we show here that the specific ablation of Pten in adult mouse DA neurons leads to activation of mTOR pathway and is neuroprotective in genetic (TifIa deletion) and neurotoxin-induced (MPTP or 6OHDA) mouse models of PD. Adult mice with DA neuron-specific Pten deletion exhibit elevated expression of tyrosine hydroxylase, a rate-limiting enzyme in the dopamine biosynthesis pathway, associated with increased striatal dopamine content, and increased mRNA levels of Foxa2, Pitx3, En1, Nurr1, and Lmx1b-the essential factors for maintaining physiological functions of adult DA neurons. Pten deletion attenuates the loss of tyrosine hydroxylase-positive cells after 6OHDA treatment, restores striatal dopamine in TifIa-knockout and MPTP-treated mice, and rescues locomotor impairments caused by TifIa loss. Inhibition of Pten-dependent functions in adult DA neurons may represent a promising PD therapy.


Assuntos
Regulação da Expressão Gênica/fisiologia , Neurônios/metabolismo , PTEN Fosfo-Hidrolase/metabolismo , Doença de Parkinson/prevenção & controle , 1-Metil-4-Fenil-1,2,3,6-Tetra-Hidropiridina/efeitos adversos , Animais , Corpo Estriado/metabolismo , Di-Hidroxifenilalanina/análogos & derivados , Di-Hidroxifenilalanina/toxicidade , Modelos Animais de Doenças , Dopamina/metabolismo , Dopaminérgicos/toxicidade , Deleção de Genes , Camundongos , Camundongos Knockout , PTEN Fosfo-Hidrolase/genética , Doença de Parkinson/etiologia , Doença de Parkinson/genética , Proteínas Pol1 do Complexo de Iniciação de Transcrição/genética , Proteínas Pol1 do Complexo de Iniciação de Transcrição/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Serina-Treonina Quinases TOR/metabolismo , Tirosina 3-Mono-Oxigenase/metabolismo
15.
Antioxidants (Basel) ; 11(3)2022 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-35326154

RESUMO

Oxidative stress is typically reported in neurodegenerative diseases [...].

16.
Acta Biomater ; 146: 235-247, 2022 07 01.
Artigo em Inglês | MEDLINE | ID: mdl-35487425

RESUMO

Vertically aligned carbon nanofibers (VACNFs) are promising material candidates for neural biosensors due to their ability to detect neurotransmitters in physiological concentrations. However, the expected high rigidity of CNFs could induce mechanical mismatch with the brain tissue, eliciting formation of a glial scar around the electrode and thus loss of functionality. We have evaluated mechanical biocompatibility of VACNFs by growing nickel-catalyzed carbon nanofibers of different lengths and inter-fiber distances. Long nanofibers with large inter-fiber distance prevented maturation of focal adhesions, thus constraining cells from obtaining a highly spread morphology that is observed when astrocytes are being contacted with stiff materials commonly used in neural implants. A silicon nanopillar array with 500 nm inter-pillar distance was used to reveal that this inhibition of focal adhesion maturation occurs due to the surface nanoscale geometry, more precisely the inter-fiber distance. Live cell atomic force microscopy was used to confirm astrocytes being significantly softer on the long Ni-CNFs compared to other surfaces, including a soft gelatin hydrogel. We also observed hippocampal neurons to mature and form synaptic contacts when being cultured on both long and short carbon nanofibers, without having to use any adhesive proteins or a glial monoculture, indicating high cytocompatibility of the material also with neuronal population. In contrast, neurons cultured on a planar tetrahedral amorphous carbon sample showed immature neurites and indications of early-stage apoptosis. Our results demonstrate that mechanical biocompatibility of biomaterials is greatly affected by their nanoscale surface geometry, which provides means for controlling how the materials and their mechanical properties are perceived by the cells. STATEMENT OF SIGNIFICANCE: Our research article shows, how nanoscale surface geometry determines mechanical biocompatibility of apparently stiff materials. Specifically, astrocytes were prevented from obtaining highly spread morphology when their adhesion site maturation was inhibited, showing similar morphology on nominally stiff vertically aligned carbon fiber (VACNF) substrates as when being cultured on ultrasoft surfaces. Furthermore, hippocampal neurons matured well and formed synapses on these carbon nanofibers, indicating high biocompatibility of the materials. Interestingly, the same VACNF materials that were used in this study have earlier also been proven to be capable for electrophysiological recordings and sensing neurotransmitters at physiological concentrations with ultra-high sensitivity and selectivity, thus providing a platform for future neural probes or smart culturing surfaces with superior sensing performance and biocompatibility.


Assuntos
Nanofibras , Materiais Biocompatíveis/química , Materiais Biocompatíveis/farmacologia , Carbono/química , Eletrodos , Nanofibras/química , Neuritos
17.
Biomolecules ; 12(4)2022 04 09.
Artigo em Inglês | MEDLINE | ID: mdl-35454152

RESUMO

There are several links between insulin resistance and neurodegenerative disorders such as Parkinson's disease. However, the direct influence of insulin signaling on abnormal α-synuclein accumulation-a hallmark of Parkinson's disease-remains poorly explored. To our best knowledge, this work is the first attempt to investigate the direct effects of insulin signaling on pathological α-synuclein accumulation induced by the addition of α-synuclein preformed fibrils in primary dopaminergic neurons. We found that modifying insulin signaling through (1) insulin receptor inhibitor GSK1904529A, (2) SHIP2 inhibitor AS1949490 or (3) PTEN inhibitor VO-OHpic failed to significantly affect α-synuclein aggregation in dopaminergic neurons, in contrast to the aggregation-reducing effects observed after the addition of glial cell line-derived neurotrophic factor. Subsequently, we tested different media formulations, with and without insulin. Again, removal of insulin from cell culturing media showed no effect on α-synuclein accumulation. We observed, however, a reduced α-synuclein aggregation in neurons cultured in neurobasal medium with a B27 supplement, regardless of the presence of insulin, in contrast to DMEM/F12 medium with an N2 supplement. The effects of culture conditions were present only in dopaminergic but not in primary cortical or hippocampal cells, indicating the unique sensitivity of the former. Altogether, our data contravene the direct involvement of insulin signaling in the modulation of α-synuclein aggregation in dopamine neurons. Moreover, we show that the choice of culturing media can significantly affect preformed fibril-induced α-synuclein phosphorylation in a primary dopaminergic cell culture.


Assuntos
Doença de Parkinson , alfa-Sinucleína , Técnicas de Cultura de Células , Dopamina , Neurônios Dopaminérgicos , Humanos , Insulina/farmacologia , Doença de Parkinson/patologia
18.
Front Physiol ; 13: 877565, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-35574464

RESUMO

Ptch receptors 1 and 2 mediate Hedgehog signaling pivotal for organ development and homeostasis. In contrast to embryonic lethal Ptch1 -/- phenotype, Ptch2 -/- mice display no effect on gross phenotype. In this brief report, we provide evidence of changes in the putative incisor mesenchymal stem cell (MSC) niches that contribute to accelerated incisor growth, as well as intriguing changes in the bones and skin which suggest a role for Ptch2 in the regulation of MSCs and their regenerative potential. We employed histological, immunostaining, and computed tomography (µCT) analyses to analyze morphological differences between Ptch2 -/- and wild-type incisors, long bones, and skins. In vitro CFU and differentiation assays were used to demonstrate the MSC content and differentiation potential of Ptch2 -/- bone marrow stromal cells. Wound healing assay was performed in vivo and in vitro on 8-week-old mice to assess the effect of Ptch2 on the wound closure. Loss of Ptch2 causes increases in the number of putative MSCs in the continuously growing incisor, associated with increased vascularization observed in the tooth mesenchyme and the neurovascular bundle. Increased length and volume of Ptch2 -/- bones is linked with the increased number and augmented in vitro differentiation potential of MSCs in the bone marrow. Dynamic changes in the Ptch2 -/- skin thickness relate to changes in the mesenchymal compartment and impact the wound closure potential. The effects of Ptch2 abrogation on the postnatal MSCs suggest a crucial role for Ptch2 in Hedgehog signaling regulation of the organ regenerative potential.

19.
ACS Chem Neurosci ; 12(13): 2273-2279, 2021 07 07.
Artigo em Inglês | MEDLINE | ID: mdl-34110772

RESUMO

Neurodegenerative diseases are associated with failed proteostasis and accumulation of insoluble protein aggregates that compromise neuronal function and survival. In Parkinson's disease, a major pathological finding is Lewy bodies and neurites that are mainly composed of phosphorylated and aggregated α-synuclein and fragments of organelle membranes. Here, we analyzed a series of selective inhibitors acting on multidomain proteins CBP and p300 that contain both lysine acetyltransferase and bromodomains and are responsible for the recognition and enzymatic modification of lysine residues. By using high-affinity inhibitors, A-485, GNE-049, and SGC-CBP30, we explored the role of two closely related proteins, CBP and p300, as promising targets for selective attenuation of α-synuclein aggregation. Our data show that selective CBP/p300 inhibitors may alter the course of pathological α-synuclein accumulation in primary mouse embryonic dopaminergic neurons. Hence, drug-like CBP/p300 inhibitors provide an effective approach for the development of high-affinity drug candidates preventing α-synuclein aggregation via systemic administration.


Assuntos
Doença de Parkinson , alfa-Sinucleína , Animais , Neurônios Dopaminérgicos , Corpos de Lewy , Camundongos , Domínios Proteicos
20.
Methods Protoc ; 3(4)2020 Sep 24.
Artigo em Inglês | MEDLINE | ID: mdl-32987935

RESUMO

Oxidative stress is prominent in many neurodegenerative diseases. Along with mitochondrial dysfunction and pathological protein aggregation, increased levels of reactive oxygen and nitrogen species, together with impaired antioxidant defense mechanisms, are frequently observed in Alzheimer's, Parkinson's, Huntington's disease and amyotrophic lateral sclerosis. The presence of oxidative stress markers in patients' plasma and cerebrospinal fluid may aid early disease diagnoses, as well as provide clues regarding the efficacy of experimental disease-modifying therapies in clinical trials. In preclinical animal models, the detection and localization of oxidatively damaged lipids, proteins and nucleic acids helps to identify most vulnerable neuronal populations and brain areas, and elucidate the molecular pathways and the timeline of pathology progression. Here, we describe the protocol for the detection of oxidative stress markers using immunohistochemistry on formaldehyde-fixed, paraffin-embedded tissue sections, applicable to the analysis of postmortem samples and tissues from animal models. In addition, we provide a simple method for the detection of malondialdehyde in tissue lysates and body fluids, which is useful for screening and the identification of tissues and structures in the nervous system which are most affected by oxidative stress.

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