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Glioblastoma multiforme (GBM) is the most common type of cancer that affects the central nervous system (CNS). It currently accounts for about 2% of diagnosed malignant tumors worldwide, with 296,000 new cases reported per year. The first-choice treatment consists of surgical resection, radiotherapy, and adjuvant chemotherapy, which increases patients' survival by 15 months. New clinical and pre-clinical research aims to improve this prognosis by proposing the search for new drugs that effectively eliminate cancer cells, circumventing problems such as resistance to treatment. One of the promising therapeutic strategies in the treatment of GBM is the inhibition of the phosphatidylinositol 3-kinase (PI3K) pathway, which is closely related to the process of tumor carcinogenesis. This review sought to address the main scientific studies of synthetic or natural drug prototypes that target specific therapy co-directed via the PI3K pathway, against human glioblastoma.
Assuntos
Neoplasias Encefálicas , Glioblastoma , Humanos , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Glioblastoma/metabolismo , Fosfatidilinositol 3-Quinases/genética , Fosfatidilinositol 3-Quinases/metabolismo , Transdução de Sinais , Neoplasias Encefálicas/tratamento farmacológico , Neoplasias Encefálicas/genética , Neoplasias Encefálicas/patologiaRESUMO
Different cancers have multiple genetic mutations, which vary depending on the affected tumour tissue. Small biopsies may not always represent all the genetic landscape of the tumour. To improve the chances of identifying mutations at different disease stages (early, during the disease course, and refractory stage), liquid biopsies offer an advantage to traditional tissue biopsy. In addition, it is possible to detect mutations related to metastatic events depending on the cancer types analysed as will be discussed in this case report, which describes a patient with brain metastasis and lung cancer that harboured K-RAS mutations both in the brain tumour and in the ctDNA present in the bloodstream.
Assuntos
Neoplasias Encefálicas , Neoplasias Pulmonares , Humanos , Biópsia Líquida , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/diagnóstico , Mutação , Biópsia , Neoplasias Encefálicas/genética , Biomarcadores TumoraisRESUMO
PURPOSE: RAS genes are among the most frequently mutated genes in cancer, where their mutation frequency varies according to the distinct RAS isoforms and tumour types. Despite occurring more prevalent in malignant tumours, RAS mutations were also observed in few benign tumours. Pituitary adenomas are examples of benign tumours which vary in size and aggressiveness. The present study was performed to investigate, via liquid biopsy and tissue analysis, the presence of K-RAS mutations in a pituitary macroadenoma. METHODS: Molecular analysis was performed to investigate K-RAS mutations using the droplet digital PCR (ddPCR) method by evaluating both plasma (liquid biopsy) and the solid tumour of a patient diagnosed with a giant clinically non-functioning pituitary tumour. RESULTS: The patient underwent surgical resection due to visual loss, and the histopathological analysis showed a gonadotrophic pituitary macroadenoma. The molecular analysis revealed the presence of mutant K-RAS both in the plasma and in the tumour tissue which, to our knowledge, has not been previously reported in the literature. CONCLUSION: Our findings highlight the exceptional capacity of the digital PCR in detecting low frequency mutations (below 1%), since we detected, for the first time, K-RAS mutations in pituitary macroadenoma. The potential impact of K-RAS mutations in these tumours should be further investigated.
Assuntos
Adenoma , Neoplasias Hipofisárias , Proteínas Proto-Oncogênicas p21(ras) , Adenoma/genética , Genes ras , Humanos , Mutação/genética , Neoplasias Hipofisárias/genética , Reação em Cadeia da Polimerase , Proteínas Proto-Oncogênicas p21(ras)/genéticaRESUMO
The ATP-binding cassette transporters (ABC transporters) have been intensely studied over the past 50 years for their involvement in the multidrug resistance (MDR) phenotype, especially in cancer. They are frequently overexpressed in both naive and post-treatment tumors, and hinder effective chemotherapy by reducing drug accumulation in cancer cells. In the last decade however, several studies have established that ABC transporters have additional, fundamental roles in tumor biology; there is strong evidence that these proteins are involved in transporting tumor-enhancing molecules and/or in protein-protein interactions that impact cancer aggressiveness, progression, and patient prognosis. This review highlights these studies in relation to some well-described cancer hallmarks, in an effort to re-emphasize the need for further investigation into the physiological functions of ABC transporters that are critical for tumor development. Unraveling these new roles offers an opportunity to define new strategies and targets for therapy, which would include endogenous substrates or signaling pathways that regulate these proteins.
Assuntos
Transportadores de Cassetes de Ligação de ATP/metabolismo , Resistência a Múltiplos Medicamentos/fisiologia , Resistencia a Medicamentos Antineoplásicos/fisiologia , Neoplasias/fisiopatologia , Humanos , Células-Tronco Neoplásicas , Distribuição TecidualRESUMO
Synovial fluid holds a population of mesenchymal stem cells (MSC) that could be used for clinical treatment. Our goal was to characterize the inflammatory and metabolomic profile of the synovial fluid from osteoarthritic patients and to identify its modulatory effect on synovial fluid cells. Synovial fluid was collected from non-OA and OA patients, which was centrifuged to isolate cells. Cells were cultured for 21 days, characterized with specific markers for MSC, and exposed to a specific cocktail to induce chondrogenic, osteogenic, and adipogenic differentiation. Then, we performed a MTT assay exposing SF cells from non-OA and OA patients to a medium containing non-OA and OA synovial fluid. Synovial fluid from non-OA and OA patients was submitted to ELISA to evaluate BMP-2, BMP-4, IL-6, IL-10, TNF-α, and TGF-ß1 concentrations and to a metabolomic evaluation using 1H-NMR. Synovial fluid cells presented spindle-shaped morphology in vitro. Samples from OA patients formed a higher number of colonies than the ones from non-OA patients. After 21 days, the colony-forming cells from OA patients differentiated into the three mesenchymal cell lineages, under the appropriated induction protocols. Synovial fluid cells increased its metabolic activity after being exposed to the OA synovial fluid. ELISA assay showed that OA synovial fluid samples presented higher concentration of IL-10 and TGF-ß1 than the non-OA, while the NMR showed that OA synovial fluid presents higher concentrations of glucose and glycerol. In conclusion, SFC activity is modulated by OA synovial fluid, which presents higher concentration of IL-10, TGF-ß, glycerol, and glucose.
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Zika virus (ZIKV) has become a major challenge for scientists and health agencies. ZIKV's involvement with human fetal microcephaly and Guillain-Barré syndrome and its transmission through Aedes africanus and Aedes aegypti mosquitos highlighted the epidemiological and neurological risks associated to ZIKV infection. In 2013, ZIKV arrives in Brazil but the first outbreak in the country was reported in 2015. Here, we used the Web of Science as a search tool for comparing the evolution of world and Brazilian scientific research on dengue virus (DENV)-also present in mosquito-, ZIKV and microcephaly. The association between ZIKV and microcephaly was only evidenced in 2015. Interestingly, Brazil and the USA are the responsible for most of these reports. Furthermore, the level of double-counted articles indicates a high degree of international collaborative effort in studying ZIKV and microcephaly. The ZIKV research clearly requires multidisciplinary expertise including epidemiologic, clinical, virological, and neurochemical backgrounds. This letter intends to emphasize the need of multidisciplinary studies and put forward some as yet unanswered questions in attempting to contribute to the understanding of this multifaceted health problem. In line with this, we recently constituted a collaborative and multidisciplinary taskforce encompassing eight Brazilian scientific institutions of excellence, The ZIKV translational research taskforce. This taskforce comprises a vast international network of collaborators and welcomes additional collaborators. We intend to advance fast in terms of mechanisms, which can potentially contribute to treat or halt ZIKV spreading around the world.
Assuntos
Infecção por Zika virus , Zika virus , Animais , Brasil , Surtos de Doenças , Humanos , Neurociências , Pesquisa Translacional BiomédicaRESUMO
Flavonoids are polyphenolic compounds found throughout the plant kingdom. They occur in every organ but are usually concentrated in leaves and flowers. During the last two decades, in vitro and in vivo studies demonstrated that flavonoids have inhibitory effects on human diseases through targeting of multiple cellular signaling components. Wnt/ß-catenin signaling regulates proliferation, differentiation and fate specification in developmental stages and controls tissue homeostasis in adult life. For these reasons, this pathway has received great attention in the last years as potential pathway involved in distinct Human pathologies. In this review we discuss the emerging potential mechanisms for flavonoids on Wnt/ß-catenin signaling in cancer and possible investigation strategies to understand flavonoids mode of action on this signaling pathway.
Assuntos
Flavonoides/farmacologia , Neoplasias/fisiopatologia , Transdução de Sinais/efeitos dos fármacos , Proteínas Wnt/efeitos dos fármacos , beta Catenina/fisiologia , Animais , Humanos , Plantas/químicaRESUMO
Glioblastomas (GBMs) are considered to be one of the deadliest human cancers, characterized by a high proliferative rate, aggressive invasiveness and insensitivity to radio- and chemotherapy, as well as a short patient survival period. Moreover, GBMs are among the most vascularized and invasive cancers in humans. Angiogenesis in GBMs is correlated with the grade of malignancy and is inversely correlated with patient survival. One of the first steps in tumor invasions is migration. GBM cells have the ability to infiltrate and disrupt physical barriers such as basement membranes, extracellular matrix and cell junctions. The invasion process includes the overexpression of several members of a super-family of zinc-based proteinases, the Metzincin, in particular a sub-group, metalloproteinases. Another interesting aspect is that, inside the GBM tissue, there are up to 30% of microglia or macrophages. However, little is known about the immune performance and interactions of the microglia with GBMs. These singular properties of GBMs will be described here. A sub-population of cells with stem-like properties may be the source of tumors since, apparently, GBM stem cells (GSCs) are highly resistant to current cancer treatments. These cancer therapies, while killing the majority of tumor cells, ultimately fail in GBM treatment because they do not eliminate GSCs, which survive to regenerate new tumors. Finally, GBM patient prognostic has shown little improvement in decades. In this context, we will discuss how the membrane-acting toxins called cytolysins can be a potential new tool for GBM treatment.
Assuntos
Glioblastoma/patologia , Neoplasias do Sistema Nervoso/patologia , Animais , Glioblastoma/irrigação sanguínea , Humanos , Metaloproteases/fisiologia , Invasividade Neoplásica/patologia , Células-Tronco Neoplásicas/fisiologia , Neovascularização Patológica/patologia , Neoplasias do Sistema Nervoso/irrigação sanguínea , Proteínas Citotóxicas Formadoras de Poros/metabolismoRESUMO
Glial cells are currently viewed as active partners of neurons in synapse formation. The close proximity of astrocytes to the synaptic cleft implicates that they strongly influence synapse function as well as suggests that these cells might be potential targets for neuronal-released molecules. In this review, we discuss the signaling pathways of astrocyte generation and the role of astrocyte-derived molecules in synapse formation in the central nervous system. Further, we discuss the role of the excitatory neurotransmitter, glutamate and transforming growth factor beta 1 (TGF-ß1) pathway in astrocyte generation and differentiation. We provide evidence that astrocytes surrounding synapses are target of neuronal activity and shed light into the role of astroglial cells into neurological disorders associated with glutamate neurotoxicity.
Assuntos
Astrócitos/fisiologia , Diferenciação Celular/fisiologia , Neuroglia/fisiologia , Neurônios/fisiologia , Sinapses/fisiologia , Animais , Ácido Glutâmico/fisiologia , Humanos , Peptídeos e Proteínas de Sinalização Intercelular/fisiologia , Doenças Neurodegenerativas/patologia , Neurotransmissores/fisiologia , Transdução de Sinais/fisiologia , Fator de Crescimento Transformador beta1/fisiologiaRESUMO
The objectives of this study were to investigate the presence of the three neurofilament subunits, ubiquitin, proteasome and 3-nitrotyrosine, in CSF samples of ALS patients. CSF samples were obtained by lumbar puncture from 10 ALS patients and six controls. All samples were analysed by Western blotting. Results revealed that neurofilament heavy subunit was identified in 70% of ALS cases and we conclude that this subunit may be a promising biomarker for clinical diagnosis of ALS.
Assuntos
Esclerose Lateral Amiotrófica/líquido cefalorraquidiano , Esclerose Lateral Amiotrófica/diagnóstico , Biomarcadores/líquido cefalorraquidiano , Proteínas de Neurofilamentos/líquido cefalorraquidiano , Subunidades Proteicas/líquido cefalorraquidiano , Adulto , Idoso , Esclerose Lateral Amiotrófica/patologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Neurônios/citologia , Neurônios/metabolismo , Medula Espinal/citologia , Medula Espinal/metabolismo , Medula Espinal/patologia , Tirosina/análogos & derivados , Tirosina/metabolismoRESUMO
Isoquercitrin isolated from the aerial parts of Hyptis fasciculata was evaluated according to its capacity to interfere with glioblastoma (Gbm) cell growth. Gbm cells were incubated with isoquercitrin, quercetin, or rutin at concentrations of 25, 50, and 100 mumol/l for 24, 48, and 72 h. Quercetin and rutin affected Gbm cell proliferation after treatment times of longer than 24 h. However, increasing concentrations of isoquercitrin inhibited 50% of Gbm cell proliferation at 24 h and further reached nearly 90% inhibition at 72 h. This effect did not affect cell morphology, cell viability, or cleaved capase-3 levels, indicating that isoquercitrin did not induce Gbm cell death. A marked reduction in cyclin D1 levels and an increase in p27 levels were observed when 100 micromol/l of isoquercitrin was added to Gbm cells. Interestingly, nuclear beta-catenin staining observed in a subpopulation of untreated Gbm cells was found in the cytoplasm after 100-micromol/l isoquercitrin treatment. Collectively, these data show that isoquercitrin reduces Gbm cell growth without inducing apoptosis, possibly by modulating the control of the cell cycle. Our data also suggest that beta-catenin-mediated signaling may be involved on the antiproliferative activity of isoquercitrin.
Assuntos
Antineoplásicos Fitogênicos/farmacologia , Glioblastoma/tratamento farmacológico , Hyptis/química , Quercetina/análogos & derivados , Antineoplásicos Fitogênicos/administração & dosagem , Antineoplásicos Fitogênicos/isolamento & purificação , Ciclo Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Proliferação de Células/efeitos dos fármacos , Ciclina D1/efeitos dos fármacos , Ciclina D1/metabolismo , Inibidor de Quinase Dependente de Ciclina p27/efeitos dos fármacos , Inibidor de Quinase Dependente de Ciclina p27/metabolismo , Relação Dose-Resposta a Droga , Glioblastoma/fisiopatologia , Humanos , Quercetina/administração & dosagem , Quercetina/isolamento & purificação , Quercetina/farmacologia , Rutina/administração & dosagem , Rutina/farmacologia , Fatores de Tempo , beta Catenina/metabolismoRESUMO
Multidrug resistance in gliomas is the major challenges in the clinical setting. We investigated the expression of P-glycoprotein (Pgp) and multidrug resistance-related protein 1 (MRP1) in 50 gliomas using immunohistochemistry. Compared to Pgp, MRP1 positivity was observed in highest percentage of gliomas grade IV samples (p = 0.008). Unlike MRP1 expression observed in high-grade, gliomas grade II exhibited a greater number of Pgp positive samples as compared to grades III and IV (p = 0.026). Our results suggest that the difference between the histological grade gliomas regarding MRP1 and Pgp expression must have implications in the choice of chemotherapeutic protocols.
Assuntos
Membro 1 da Subfamília B de Cassetes de Ligação de ATP/biossíntese , Glioma/patologia , Proteínas Associadas à Resistência a Múltiplos Medicamentos/biossíntese , Adolescente , Adulto , Idoso , Criança , Pré-Escolar , Feminino , Glioma/tratamento farmacológico , Glioma/metabolismo , Humanos , Imuno-Histoquímica , Masculino , Pessoa de Meia-Idade , Estadiamento de Neoplasias , Adulto JovemRESUMO
Glial cells are currently viewed as active partners of neurons in synapse formation. The close proximity of astrocytes to the synaptic cleft suggests that these cells might be potential targets for neuronal-released molecules although this issue has been less addressed. Here, we evaluated the role of the excitatory neurotransmitter, glutamate, in astrocyte differentiation. We recently demonstrated that cortical neurons activate the gene promoter of the astrocyte maturation marker, GFAP (glial fibrillary acidic protein) of cerebral cortex astrocytes by inducing TGF-beta1 (transforming growth factor beta 1) secretion in vitro. To access the effect of glutamate on GFAP gene, we used transgenic mice bearing the beta-Galactosidase (beta-Gal) reporter gene under the regulation of the GFAP gene promoter. We report that 100 muM glutamate activates the GFAP gene promoter of astrocytes from cerebral cortex revealed by a significant increase in the number of beta-Gal positive astrocytes. Neutralizing antibodies against TGF-beta completely prevented glutamate and neuronal-induction of GFAP gene, thus indicating that this event is mediated by TGF-beta1. Further, induction of GFAP gene in response to glutamate was followed by nuclear translocation of the Smad transcription factor, a hallmark of TGF-beta1 pathway activation. The antagonist of the metabotropic glutamate receptor, MCPG, inhibited neuronal effect suggesting that neuronal activation of GFAP gene promoter involves glutamate metabotropic receptors. MAPK (PD98059) and PI3K (LY294002) inhibitors fully prevented activation of GFAP gene promoter by all treatments. Surprisingly, these inhibitors also abrogated TGF-beta1 direct action on GFAP gene although they did not inhibit Smad-2 phosphorylation, suggesting that TGF-beta1-induced GFAP gene activation might involve cooperation between the canonical and non-canonical TGF-beta pathways. Together, our results suggest that glial metabotropic glutamate 2/3 receptor activation by neurons induces TGF-beta1 secretion, leading to GFAP gene activation and astrocyte differentiation and involves Smad and MAPK/PI3K pathways. Our work provides evidence that astrocytes surrounding synapses are target of neuronal activity and might shed light into the role of glial cells into neurological disorders associated with glutamate neurotoxicity.
Assuntos
Astrócitos/efeitos dos fármacos , Proteína Glial Fibrilar Ácida/genética , Ácido Glutâmico/farmacologia , Regiões Promotoras Genéticas/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Fator de Crescimento Transformador beta/metabolismo , Animais , Astrócitos/ultraestrutura , Encéfalo/citologia , Células Cultivadas , Meios de Cultivo Condicionados/farmacologia , Relação Dose-Resposta a Droga , Embrião de Mamíferos , Inibidores Enzimáticos/farmacologia , Antagonistas de Aminoácidos Excitatórios/farmacologia , Regulação da Expressão Gênica/efeitos dos fármacos , Proteína Glial Fibrilar Ácida/metabolismo , Camundongos , Camundongos Transgênicos , Neurônios/química , Regiões Promotoras Genéticas/fisiologia , Sinaptossomos/efeitos dos fármacos , Sinaptossomos/metabolismo , Ativação Transcricional , Fator de Crescimento Transformador beta/farmacologia , beta-Galactosidase/metabolismoRESUMO
We investigate properties of a reported new mechanism for cell-cell interactions, tunneling nanotubes (TNT's). TNT's mediate actin-based transfer of vesicles and organelles and they allow signal transmission between cells. The effects of lateral pulling with polystyrene beads trapped by optical tweezers on TNT's linking separate U-87 MG human glioblastoma cells in culture are described. This cell line was chosen for handling ease and possible pathology implications of TNT persistence in communication between cancerous cells. Observed nanotubes are shown to have the characteristic features of TNT's. We find that pulling induces two different types of TNT bifurcations. In one of them, termed V-Y bifurcation, the TNT is first distorted into a V-shaped form, following which a new branch emerges from the apex. In the other one, termed I-D bifurcation, the pulled TNT is bent into a curved arc of increasingly broader span. Curves showing the variation of pulling force with displacement are obtained. Results yield information on TNT structure and elastic properties.
Assuntos
Comunicação Celular , Actinas/metabolismo , Linhagem Celular Tumoral , Elasticidade , Glioblastoma/patologia , Humanos , Microscopia Eletrônica de Varredura , Microesferas , Pinças Ópticas , Estresse MecânicoRESUMO
Multidrug resistance (MDR) is an obstacle in cancer treatment. An understanding of how tumoral cells react to oxidants can help us elucidate the cellular mechanism involved in resistance. Microcystins are cyanobacteria hepatotoxins known to generate oxidative stress. The aim of this study was to compare the sensitivity to microcystins of human tumoral cell lines with (Lucena) and without (K562) MDR phenotype. Endpoints analyzed were effective microcystins concentration to 50% of exposed cells (EC50), antioxidant enzyme activity, lipid peroxidation, DNA damage, reactive oxygen species (ROS) concentration, and tubulin content. Lucena were more resistant and showed lower DNA damage than K562 cells (P<0.05). Although microcystins did not alter catalase activity, a higher mean value was observed in Lucena than in K562 cells. Lucena cells also showed lower ROS concentration and higher tubulin content. The higher metabolism associated with the MDR phenotype should increase ROS concentration and make for an improved antioxidant defense against the toxic effects of microcystins.
Assuntos
Resistência a Múltiplos Medicamentos , Resistencia a Medicamentos Antineoplásicos , Microcistinas/farmacologia , Oxidantes/farmacologia , Espécies Reativas de Oxigênio/metabolismo , Linhagem Celular Tumoral , Humanos , Células K562 , Redes e Vias Metabólicas , Tubulina (Proteína)/metabolismoRESUMO
Pb(II) is a neurotoxic pollutant that produces permanent cognitive deficits in children. Pb(II) can modulate cell signaling pathways and cell viability in a variety of cell types. However, these actions are not well demonstrated on glial cells, which represent an important target for metals into the central nervous system. The present work was undertaken to determine the ability of Pb(II) in modulating the activity of mitogen activated protein kinases (MAPKs) in cultures of C6 rat glioma cells, a useful functional model for the study of astrocytes. Additionally, cell viability was analyzed by measurement of MTT reduction. Cells were exposed to lead acetate 0.1, 1, 10 microM for 24 and 48 h. MAPKs activation - in particular ERK1/2, p38(MAPK) and JNK1/2 - were analyzed by western blotting. Results showed that 10 microM Pb(II) treatment for 24 h caused a discrete stimulation of p38(MAPK) phosphorylation. However, 1 and 10 microM Pb(II) treatment for 48 h provoked a significant stimulation in the phosphorylation state of p38(MAPK) and JNK1/2. The phosphorylation state of ERK1/2 was not modified by any Pb(II) treatment. Moreover, data indicate that at 48 h treatment even 1 microM Pb(II) can be cytotoxic, causing impairment on cell viability. Therefore, depending on a long incubation period, a significant concomitant activation of p38(MAPK) and JNK1/2 by Pb(II) took place in parallel with the impairment of C6 glioma cells viability.
Assuntos
Neoplasias Encefálicas/enzimologia , Poluentes Ambientais/toxicidade , Glioma/enzimologia , Sistema de Sinalização das MAP Quinases/efeitos dos fármacos , Proteína Quinase 8 Ativada por Mitógeno/metabolismo , Proteína Quinase 9 Ativada por Mitógeno/metabolismo , Compostos Organometálicos/toxicidade , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismo , Animais , Neoplasias Encefálicas/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Relação Dose-Resposta a Droga , Glioma/patologia , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Fosforilação , Ratos , Fatores de TempoRESUMO
Parkinson's disease (PD) is characterized by the presence of cytoplasmic inclusions composed of alpha-synuclein (alpha-syn) in dopaminergic neurons. This suggests a pivotal role of dopamine (DA) on PD development. Here, we show that DA modulates differently the stability of protofibrils (PF) and fibrils (F) composed of wild type or variants of alpha-syn (A30P and A53T) as probed by high hydrostatic pressure (HHP). While in the absence of DA, all alpha-syn PF exhibited identical stability, in its presence, the variant-composed PF acquired a greater stability (DAPFwt < DAPFA30P = DAPFA53T), implying that they would last longer, which could shed light onto why these mutations are so aggressive. When alpha-syn was incubated for long times (18 days) in the presence of DA, we observed the formation of F by electronic microscopy, suggesting that the PF trapped in the presence of DA in short times can evolve into F. The stability of F was also altered by DA. DAFwt was more labile than Fwt, indicating that the former would be more susceptible to breakage. PFA30P and DAPFA30P, when added to mesencephalic and cortical neurons in culture, decreased the number and length of neurites and increased the number of apoptotic cells. Surprisingly, these toxic effects of PFA30P and DAPFA30P were practically abolished with HHP treatment, which was able to break the PF into smaller aggregates, as seen by atomic force microscopy. These results suggest that strategies aimed at breaking and/or clearing these aggregates is promising in alleviating the symptoms of PD.
Assuntos
Dopamina/farmacologia , alfa-Sinucleína/química , alfa-Sinucleína/metabolismo , Substituição de Aminoácidos , Dopamina/metabolismo , Estabilidade de Medicamentos , Variação Genética , Humanos , Pressão Hidrostática , Técnicas In Vitro , Microscopia de Força Atômica , Microscopia Eletrônica , Complexos Multiproteicos , Neurônios/metabolismo , Doença de Parkinson/etiologia , Doença de Parkinson/metabolismo , Proteínas Recombinantes/química , Proteínas Recombinantes/efeitos dos fármacos , Proteínas Recombinantes/genética , Proteínas Recombinantes/metabolismo , Água/química , alfa-Sinucleína/efeitos dos fármacos , alfa-Sinucleína/genéticaRESUMO
Thyroid hormone deficiency during the critical period of neural differentiation produces permanent and severe alterations in the morphology and function of the nervous system leading to cretinism. Perinatal hypothyroidism results in permanent alterations of hippocampal synaptic functions in adult rats consequently causing learning and memory impairment. Mitogen-activated protein kinases (MAPKs) are a family of protein kinases that regulate essential cellular activities ranging from gene expression, mitosis, programmed cell death to plasticity and memory formation, but their involvement in perinatal hypothyroidism is not determined. The present work was designed to investigate MAPKs phosphorylation in hippocampus of congenital neonatal hypothyroid rats. Congenital hypothyroidism promotes an increase in extracellular signal-regulated kinases 1/2 (ERK 1/2) phosphorylation (+50%) and a decrease in p38(MAPK) phosphorylation (-50%) without changing in Jun N-terminal kinases (JNK) phosphorylation. Therefore, the congenital hypothyroidism model disturbs ERK 1/2 and p38(MAPK) phosphorylation pathways causing an important molecular alteration in the hippocampus. This event might be related, at least partially, to the deficits in hippocampal development and cognitive functions due neonatal congenital hypothyroidism.
Assuntos
Predisposição Genética para Doença/genética , Hipocampo/enzimologia , Hipotireoidismo/complicações , Sistema de Sinalização das MAP Quinases/fisiologia , Transtornos da Memória/enzimologia , Animais , Animais Recém-Nascidos , Diferenciação Celular/genética , Hipotireoidismo Congênito/enzimologia , Hipotireoidismo Congênito/genética , Hipotireoidismo Congênito/fisiopatologia , Modelos Animais de Doenças , Regulação para Baixo/genética , Feminino , Hipocampo/crescimento & desenvolvimento , Hipocampo/fisiopatologia , Hipotireoidismo/fisiopatologia , Proteínas Quinases JNK Ativadas por Mitógeno/metabolismo , Masculino , Transtornos da Memória/genética , Transtornos da Memória/fisiopatologia , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Fosforilação , Ratos , Ratos Wistar , Regulação para Cima/genética , Proteínas Quinases p38 Ativadas por Mitógeno/metabolismoRESUMO
In the developing nervous system migrating neurons and growing axons are guided by diffusible and/or substrate-bound cues, such as extracellular matrix-associated laminin. In a previous work we demonstrated that laminin molecules could self-assemble in two different manners, giving rise to matrices that could favor either neuritogenesis or proliferation of cortical precursor cells. We investigated whether the ability of astrocytes to promote neuritogenesis of co-cultivated neurons was modulated by the assembling mode of the laminin matrix secreted by them. We compared the morphologies and neuritogenic potentials of laminin deposited by in vitro-differentiated astrocytes obtained from embryonic or neonatal rat brain cortices. We showed that, while permissive astrocytes derived from embryonic brain produced a flat laminin matrix that remained associated to the cell surface, astrocytes derived from newborn brain secreted a laminin matrix resembling a fibrillar web that protruded from the cell plane. The average neurite lengths obtained for E16 neurons cultured on each astrocyte layer were 198+/-22 and 123+/-13 microm, respectively. Analyses of surface-associated electrostatic potentials revealed that embryonic astrocytes presented a pI of -2.8, while in newborn cells this value was -3.8. Removal of the sialic acid groups on the embryonic monolayer by neuraminidase treatment led to the immediate release of matrix-associated laminin. Interestingly, laminin reassembled 1 hour after neuraminidase removal converted to the features of the newborn matrix. Alternatively, treatment of astrocytes with the cholesterol-solubilizing detergent methyl-beta-cyclodextrin also resulted in release of the extracellular laminin. To test the hypothesis that sialic-acid-containing lipids localized at cholesterol-rich membrane domains could affect the process of laminin assembly, we devised a cell-free assay where laminin polymerization was carried out over artificial lipid films. Films of either a mixture of gangliosides or pure ganglioside GT1b induced formation of matrices of morpho-functional features similar to the matrices deposited by embryonic astrocytes. Conversely, films of phosphatidylcholine or ganglioside GM1 led to the formation of bulky laminin aggregates that lacked a defined structure. We propose that the expression of negative lipids on astrocytes can control the extracellular polymerization of laminin and, consequently, the permissivity to neuritogenesis of astrocytes during development.