Assessment of melatonin-alpha adrenergic receptor complexes by molecular docking analysis / Avaliação dos complexos melatonina-receptores alfa-adrenérgicos por análises de docagem molecular

The pineal melatonin (N-acetyl-5-methoxytryptamine) is a molecule associated in a way or another with probably all physiological systems, aiming to fulfil its functional integrative roles in central nervous system activity, sleep and wakefulness cycles, energy metabolism and thermoregulation, immune, reproductive, endocrine, cardiovascular, respiratory and excretory systems. Within this context, the present study aimed to assess in silico the formation of complexes between ligand melatonin and other potential receptor proteins by molecular docking analyses. The main steps established in this experimental procedure were: a) search and selection of the 3D structure of the melatonin from DrugBank; b) search and selection of 3D structures of other target receptor proteins using STRING, protein BLAST and database PDB; and c) formation of the complexes between melatonin and receptors selected using AutoDock4.0 server by molecular docking analyses. High reliability score and significant similarity were only identified between type 1B melatonin and alpha-2A adrenergic receptor. Thus, molecular docking assays were carried out using ligand melatonin and crystallographic structures of the alpha-2A adrenergic receptor coupled to an antagonist (ID PDB 6kux) and a partial agonist (ID PDB 6kuy) available in the database PDB. Binding energy values of -6.79 and -6.98 kcal/mol and structural stability by non-covalent intermolecular interactions were predicted during the formation of complexes between melatonin and alpha-2A adrenergic receptor 6kux and 6kuy, respectively. In this way, the findings described in current study may indicate strong interactions between melatonin and adrenoceptors, suggesting its possible partial agonist effect on the activation of the alfa-2A adrenergic receptor.(AU)

A melatonina pineal (N-acetil-5-metoxitriptamina) é uma molécula associada de um modo ou outro com provavelmente todos os sistemas fisiológicos, visando cumprir seus papéis funcionais integradores na atividade do sistema nervoso central, ciclos de sono e vigília, metabolismo energético e termorregulação, sistemas imunológico, reprodutivo, endócrino, cardiovascular, respiratório e excretor. Assim, o presente estudo objetivou avaliar in silico a formação de complexos entre o ligante melatonina e outras proteínas potenciais receptoras por meio de análises de docagem molecular. As principais etapas estabelecidas neste procedimento experimental foram: a) busca e seleção da estrutura 3D da melatonina a partir do banco de dados DrugBank; b) busca e seleção de estruturas 3D de outras proteínas receptoras-alvo utilizando STRING, proteína BLAST e o banco de dados PDB; e c) avaliação da formação dos complexos entre melatonina e receptores selecionados a partir do servidor AutoDock4.0 para análises de docagem molecular. Alto escore de confiabilidade e similaridade significativa foram identificados apenas entre a melatonina do tipo 1B e o receptor alfa-2A adrenérgico. Valores de energia de ligação de -6,79 e -6,98 kcal/mol e estabilidade estrutural pela presença de interações intermoleculares não covalentes foram preditos durante a formação de complexos entre o ligante melatonina e os receptores adrenérgico alfa-2A 6kux e 6kuy, respectivamente. Dessa forma, os achados descritos no presente estudo podem indicar fortes interações entre melatonina e adrenoceptores, sugerindo seu possível efeito agonista parcial na ativação do receptor alfa-2A adrenérgico.(AU)

Culture, characterization and differentiation of neural precursors from the central nervous system of guinea pigs (Cavia porcellus Linnaeus, 1758) / Cultura, caracterização e diferenciação de precursores neurais do sistema nervoso central de porquinho-da-índia (Cavia porcellus Linnaeus, 1758)

Potentially neurogenic areas were initially identified by incorporation of bromodeoxyuridine (BrdU) in cells underlying the subventricular zone (SVZ) of the lateral ventricles wall, hippocampus and olfactory bulbs of newborn guinea pigs. Neural precursors from the SVZ were cultured in suspension, generating neurospheres (NSFs), which, upon dissociation were able to generate new NSFs. Upon culture in the absence of growth factors, cells dissociated from NSFs displayed evidence for neural differentiation, giving rise to cells from neural lineage. Flow cytometry analysis for of NSFs-derived cells after differentiation revealed approximately 13.3% nestin positive, 5.5% Beta-III-tubulin positive, 9% GFAP positive and 7.8% mGalC positive. Functional assays by measurement of calcium influx upon gamma butiric amino acid (GABA) and glutamate stimuli, revealed stimulation in differentiated cells, an indicator of neuronal differentiation. The ability of guinea pig SVZ cells to originate functional neurons in vitro is promising for research and towards a future use of neural stem cells in the therapy of neurological disorders.(AU)

Áreas potencialmente neurogênicas foram identificadas por incorporação de bromodeoxiuridina (BrdU) na zona subventricular (SVZ) dos ventrículos laterais, hipocampo e bulbos olfatórios de cobaias neonatos. Precursores neurais provenientes da SVZ foram cultivados em suspensão, resultando na geração de neuroesferas (NSFs), que quando dissociadas foram capazes de proliferar e gerar novas NSFs. Quando cultivadas na ausência de fatores de crescimento, as células provenientes de NSFs dissociadas apresentaram evidências de diferenciação neuronal, dando origem a células da linhagem neural. Citometria de fluxo em células das NSFs após a diferenciação revelou aproximadamente 13,3% positivas para nestina, 5,5% positivas para Beta-III-tubulina, 9% positivas para GFAP e 7,8% positivas para mGalC. Testes de funcionalidade pela mensuração de influxo de cálcio após estímulo com ácido gama amino butírico (GABA) e glutamato revelaram a estimulação de células diferenciadas, um indicador de função neuronal. A capacidade de células da SVZ de fetos de cobaias originarem células neurais funcionais in vitro é promissora para a pesquisa e eventual uso terapêutico de células tronco em disordens do sistema nervoso.(AU)

Culture, characterization and differentiation of neural precursors from the central nervous system of guinea pigs (Cavia porcellus Linnaeus, 1758) / Cultura, caracterização e diferenciação de precursores neurais do sistema nervoso central de porquinho-da-índia (Cavia porcellus Linnaeus, 1758)

Potentially neurogenic areas were initially identified by incorporation of bromodeoxyuridine (BrdU) in cells underlying the subventricular zone (SVZ) of the lateral ventricles wall, hippocampus and olfactory bulbs of newborn guinea pigs. Neural precursors from the SVZ were cultured in suspension, generating neurospheres (NSFs), which, upon dissociation were able to generate new NSFs. Upon culture in the absence of growth factors, cells dissociated from NSFs displayed evidence for neural differentiation, giving rise to cells from neural lineage. Flow cytometry analysis for of NSFs-derived cells after differentiation revealed approximately 13.3% nestin positive, 5.5% Beta-III-tubulin positive, 9% GFAP positive and 7.8% mGalC positive. Functional assays by measurement of calcium influx upon gamma butiric amino acid (GABA) and glutamate stimuli, revealed stimulation in differentiated cells, an indicator of neuronal differentiation. The ability of guinea pig SVZ cells to originate functional neurons in vitro is promising for research and towards a future use of neural stem cells in the therapy of neurological disorders.(AU)

Áreas potencialmente neurogênicas foram identificadas por incorporação de bromodeoxiuridina (BrdU) na zona subventricular (SVZ) dos ventrículos laterais, hipocampo e bulbos olfatórios de cobaias neonatos. Precursores neurais provenientes da SVZ foram cultivados em suspensão, resultando na geração de neuroesferas (NSFs), que quando dissociadas foram capazes de proliferar e gerar novas NSFs. Quando cultivadas na ausência de fatores de crescimento, as células provenientes de NSFs dissociadas apresentaram evidências de diferenciação neuronal, dando origem a células da linhagem neural. Citometria de fluxo em células das NSFs após a diferenciação revelou aproximadamente 13,3% positivas para nestina, 5,5% positivas para Beta-III-tubulina, 9% positivas para GFAP e 7,8% positivas para mGalC. Testes de funcionalidade pela mensuração de influxo de cálcio após estímulo com ácido gama amino butírico (GABA) e glutamato revelaram a estimulação de células diferenciadas, um indicador de função neuronal. A capacidade de células da SVZ de fetos de cobaias originarem células neurais funcionais in vitro é promissora para a pesquisa e eventual uso terapêutico de células tronco em disordens do sistema nervoso.(AU)

Primary brain T-cell lymphoma in a cat

A 10-year-old, female, mixed-breed cat was presented for necropsy with history of incoordination, circling and nystagmus or fixed gaze. Grossly, slight asymmetry was observed in the right telencephalic hemisphere, mainly in the pyriform lobe. Histologically, sheets of small round neoplastic cells were observed in the pons, midbrain, thalamus and in the subcortical white matter of the parietal, occipital and pyriform lobes. Neoplastic cells were strongly labeled with anti-CD3 antibody by means of immunohistochemistry. Anti-BLA36, CD79a and MAC387 failed to label the neoplastic cells. Based on the histopathological findings and on the immunohistochemical results, a diagnosis of primary brain T-cell lymphoma was made.

Primary brain T-cell lymphoma in a cat

A 10-year-old, female, mixed-breed cat was presented for necropsy with history of incoordination, circling and nystagmus or fixed gaze. Grossly, slight asymmetry was observed in the right telencephalic hemisphere, mainly in the pyriform lobe. Histologically, sheets of small round neoplastic cells were observed in the pons, midbrain, thalamus and in the subcortical white matter of the parietal, occipital and pyriform lobes. Neoplastic cells were strongly labeled with anti-CD3 antibody by means of immunohistochemistry. Anti-BLA36, CD79a and MAC387 failed to label the neoplastic cells. Based on the histopathological findings and on the immunohistochemical results, a diagnosis of primary brain T-cell lymphoma was made.(AU)