RESUMO
BACKGROUND: Amyotrophic lateral sclerosis (ALS) is a multifactorial fatal motoneuron disease without a cure. Ten percent of ALS cases can be pointed to a clear genetic cause, while the remaining 90% is classified as sporadic. Our study was aimed to uncover new connections within the ALS network through a bioinformatic approach, by which we identified C13orf18, recently named Pacer, as a new component of the autophagic machinery and potentially involved in ALS pathogenesis. METHODS: Initially, we identified Pacer using a network-based bioinformatic analysis. Expression of Pacer was then investigated in vivo using spinal cord tissue from two ALS mouse models (SOD1G93A and TDP43A315T) and sporadic ALS patients. Mechanistic studies were performed in cell culture using the mouse motoneuron cell line NSC34. Loss of function of Pacer was achieved by knockdown using short-hairpin constructs. The effect of Pacer repression was investigated in the context of autophagy, SOD1 aggregation, and neuronal death. RESULTS: Using an unbiased network-based approach, we integrated all available ALS data to identify new functional interactions involved in ALS pathogenesis. We found that Pacer associates to an ALS-specific subnetwork composed of components of the autophagy pathway, one of the main cellular processes affected in the disease. Interestingly, we found that Pacer levels are significantly reduced in spinal cord tissue from sporadic ALS patients and in tissues from two ALS mouse models. In vitro, Pacer deficiency lead to impaired autophagy and accumulation of ALS-associated protein aggregates, which correlated with the induction of cell death. CONCLUSIONS: This study, therefore, identifies Pacer as a new regulator of proteostasis associated with ALS pathology.
Assuntos
Esclerose Lateral Amiotrófica/metabolismo , Esclerose Lateral Amiotrófica/patologia , Autofagia/efeitos dos fármacos , Proteínas de Ligação a DNA/metabolismo , Neurônios Motores/metabolismo , Esclerose Lateral Amiotrófica/genética , Animais , Modelos Animais de Doenças , Humanos , Camundongos Transgênicos , Medula Espinal/metabolismo , Medula Espinal/patologia , Superóxido Dismutase/genética , Superóxido Dismutase/metabolismoRESUMO
Circadian timing is structured in such a way as to receive information from the external and internal environments, and its function is the timing organization of the physiological and behavioral processes in a circadian pattern. In mammals, the circadian timing system consists of a group of structures, which includes the suprachiasmatic nucleus (SCN), the intergeniculate leaflet and the pineal gland. Neuron groups working as a biological pacemaker are found in the SCN, forming a biological master clock. We present here a simple model for the circadian timing system of mammals, which is able to reproduce two fundamental characteristics of biological rhythms: the endogenous generation of pulses and synchronization with the light-dark cycle. In this model, the biological pacemaker of the SCN was modeled as a set of 1000 homogeneously distributed coupled oscillators with long-range coupling forming a spherical lattice. The characteristics of the oscillator set were defined taking into account the Kuramoto's oscillator dynamics, but we used a new method for estimating the equilibrium order parameter. Simultaneous activities of the excitatory and inhibitory synapses on the elements of the circadian timing circuit at each instant were modeled by specific equations for synaptic events. All simulation programs were written in Fortran 77, compiled and run on PC DOS computers. Our model exhibited responses in agreement with physiological patterns. The values of output frequency of the oscillator system (maximal value of 3.9 Hz) were of the order of magnitude of the firing frequencies recorded in suprachiasmatic neurons of rodents in vivo and in vitro (from 1.8 to 5.4 Hz).
Assuntos
Ritmo Circadiano/fisiologia , Mamíferos/fisiologia , Modelos Neurológicos , Animais , Corpos Geniculados/fisiologia , Oscilometria/métodos , Glândula Pineal/fisiologia , Ratos , Software , Núcleo Supraquiasmático/fisiologiaRESUMO
Circadian timing is structured in such a way as to receive information from the external and internal environments, and its function is the timing organization of the physiological and behavioral processes in a circadian pattern. In mammals, the circadian timing system consists of a group of structures, which includes the suprachiasmatic nucleus (SCN), the intergeniculate leaflet and the pineal gland. Neuron groups working as a biological pacemaker are found in the SCN, forming a biological master clock. We present here a simple model for the circadian timing system of mammals, which is able to reproduce two fundamental characteristics of biological rhythms: the endogenous generation of pulses and synchronization with the light-dark cycle. In this model, the biological pacemaker of the SCN was modeled as a set of 1000 homogeneously distributed coupled oscillators with long-range coupling forming a spherical lattice. The characteristics of the oscillator set were defined taking into account the Kuramoto's oscillator dynamics, but we used a new method for estimating the equilibrium order parameter. Simultaneous activities of the excitatory and inhibitory synapses on the elements of the circadian timing circuit at each instant were modeled by specific equations for synaptic events. All simulation programs were written in Fortran 77, compiled and run on PC DOS computers. Our model exhibited responses in agreement with physiological patterns. The values of output frequency of the oscillator system (maximal value of 3.9 Hz) were of the order of magnitude of the firing frequencies recorded in suprachiasmatic neurons of rodents in vivo and in vitro (from 1.8 to 5.4 Hz).
Assuntos
Animais , Ratos , Ritmo Circadiano/fisiologia , Modelos Neurológicos , Mamíferos/fisiologia , Corpos Geniculados/fisiologia , Oscilometria/métodos , Glândula Pineal/fisiologia , Software , Núcleo Supraquiasmático/fisiologiaRESUMO
The work relates the experience of the teaching-learning process based on the competence approach. The detail of that teaching process reveals the authors concern with the few occurrence of studies about the practical development of the competences theme in the Educational Practice and, point out to the need of more studies production in that dimension.
Assuntos
Educação Baseada em Competências/métodos , Educação em Enfermagem/métodos , Ensino/métodos , Processos Grupais , Aprendizagem , Aprendizagem Baseada em Problemas/métodosRESUMO
O trabalho relata a experiência de um processo de ensino-aprendizagem baseado na abordagem por competências. O detalhamento desse processo de ensino revela a preocupação dos autores com a pouca ocorrência de estudos sobre o desenvolvimento prático do tema competências no âmbito das práticas educativas e, apontam para a necessidade de produção de mais estudos nessa dimensão.
Assuntos
Humanos , Ensino , Educação Baseada em Competências , Educação em Enfermagem , Competência Clínica , Infecções Sexualmente Transmissíveis/prevenção & controleRESUMO
The binding of chlorpromazine (CPZ) and hemin to bovine serum albumin was studied by the fluorescence quenching technique. CPZ is a widely used anti-psychotic drug that interacts with blood components, influences bioavailability, and affects function of several biomolecules. Hemin is an important ferric residue of hemoglobin that binds within the hydrophobic region of albumin with high specificity. Quenching of the intrinsic fluorescence of bovine serum albumin (BSA) was observed by selectively exciting tryptophan residues at 290 nm. Emission spectra were recorded in the range from 300 to 450 nm for each quencher addition. Stern-Volmer graphs were plotted, and the quenching constant estimated for BSA solution titrated with hemin at 25 masculine C was 1.44 (+/- 0.05) x 10(5) M(-1). Results showed that bovine albumin tryptophans are not equally accessible to CPZ, in agreement with the idea that polar or charged quenchers have more affinity for amino acid residues on the outer wall of the protein. Hemin added to albumin solution at a molar ratio of 1:1 quenched about 25% of their fluorescence. The quenching effect of CPZ on albumin-hemin solution was stronger than on pure BSA. This increase can be the result of combined conformational changes in the structure of albumin caused firstly by hemin and then by CPZ. Our results suggest that the primary binding site for hemin on bovine albumin may be located asymmetrically between the two tryptophans along the sequence formed by subdomains IB and IIA, closer to tryptophan residue 212.
Assuntos
Antipsicóticos/farmacologia , Clorpromazina/farmacologia , Hemina/farmacologia , Soroalbumina Bovina/química , Animais , Bovinos , Interações Medicamentosas , Ligação Proteica , Soroalbumina Bovina/efeitos dos fármacos , Espectrometria de Fluorescência , Triptofano/análiseRESUMO
The binding of chlorpromazine (CPZ) and hemin to bovine serum albumin was studied by the fluorescence quenching technique. CPZ is a widely used anti-psychotic drug that interacts with blood components, influences bioavailability, and affects function of several biomolecules. Hemin is an important ferric residue of hemoglobin that binds within the hydrophobic region of albumin with high specificity. Quenching of the intrinsic fluorescence of bovine serum albumin (BSA) was observed by selectively exciting tryptophan residues at 290 nm. Emission spectra were recorded in the range from 300 to 450 nm for each quencher addition. Stern-Volmer graphs were plotted, and the quenching constant estimated for BSA solution titrated with hemin at 25ºC was 1.44 (± 0.05) x 10(5) M-1. Results showed that bovine albumin tryptophans are not equally accessible to CPZ, in agreement with the idea that polar or charged quenchers have more affinity for amino acid residues on the outer wall of the protein. Hemin added to albumin solution at a molar ratio of 1:1 quenched about 25 percent of their fluorescence. The quenching effect of CPZ on albumin-hemin solution was stronger than on pure BSA. This increase can be the result of combined conformational changes in the structure of albumin caused firstly by hemin and then by CPZ. Our results suggest that the primary binding site for hemin on bovine albumin may be located asymmetrically between the two tryptophans along the sequence formed by subdomains IB and IIA, closer to tryptophan residue 212.
Assuntos
Animais , Bovinos , Antipsicóticos , Clorpromazina , Hemina , Soroalbumina Bovina , Espectrometria de Fluorescência , Interações Medicamentosas , Ligação Proteica , TriptofanoRESUMO
The present work investigates the corticoid action on the growth of the superior cervical ganglion of the rat and describes the cortisol effect during early stages of development. The study was based on morphometric and stereological analysis of the perikarya. Eight rats were treated intraperitoneally with cortisol (1mg/Kg/day) during 36 days. Treatment was initiated in the 8th day after birth and was withdrawn one day before the sacrifice. There was a significant difference (úP0,05) for the neural mean diameter between the control group (16.78 ± 1.11mm) and treated animals (15.84 ± 0.99mm). The decrease of perikarya neuronal diameter was also demonstrated by stereological methods. Morphometrical findings may suggest alterations in superior cervical ganglion neuronal activity in rats treated for long term with cortisol.
Assuntos
Ratos , Anti-Inflamatórios/farmacologia , Gânglio Cervical Superior/anatomia & histologia , Gânglio Cervical Superior , Hidrocortisona/farmacologia , Imageamento Tridimensional , Ratos WistarRESUMO
Although radiological diagnosis is easily and readily performed by orthopanthomography, with lateral oblique and anteroposterior projections, the image of dentigerous cysts may, on some occasions, be confusing. We submit the case history of a patient whose computerized tomography data may be useful in differential diagnosis.