RESUMO
How T cells integrate environmental cues into signals that limit the magnitude and length of immune responses is poorly understood. Here, we provide data that demonstrate that B55ß, a regulatory subunit of protein phosphatase 2A, represents a molecular link between cytokine concentration and apoptosis in activated CD8+ T cells. Through the modulation of AKT, B55ß induced the expression of the proapoptotic molecule Hrk in response to cytokine withdrawal. Accordingly, B55ß and Hrk were both required for in vivo and in vitro contraction of activated CD8+ lymphocytes. We show that this process plays a role during clonal contraction, establishment of immune memory, and preservation of peripheral tolerance. This regulatory pathway may represent an unexplored opportunity to end unwanted immune responses or to promote immune memory.
Assuntos
Linfócitos T CD8-Positivos/imunologia , Memória Imunológica , Proteína Fosfatase 2/imunologia , Animais , Proteínas Reguladoras de Apoptose/genética , Proteínas Reguladoras de Apoptose/imunologia , Camundongos , Camundongos Transgênicos , Neuropeptídeos/genética , Neuropeptídeos/imunologia , Proteína Fosfatase 2/genética , Proteínas Proto-Oncogênicas c-akt/genética , Proteínas Proto-Oncogênicas c-akt/imunologiaRESUMO
Delirium, or acute confusional state, is a common manifestation in diseases that originate outside the central nervous system, affecting 30-40% of elderly hospitalized patients and up to 80% of the critically ill, even though it remains unclear if severe systemic inflammation is able or not to induce cellular disturbances and immune activation in the brain. Neuropeptides are pleotropic molecules heterogeneously distributed throughout the brain and possess a wide spectrum of functions, including regulation of the inflammatory response, so we hypothesized that they would be the major alarm system in the brain before overt microglia activation. In order to investigate this hypothesis, we induced acute pancreatitis in 8-10week old rats and collected brain tissue, 12 and 24h following pancreatic injury, to measure neuropeptide and cytokine tissue levels. We found significantly higher levels of ß-endorphin, orexin and oxytocin in the brain of rats submitted to pancreatic injury, when compared to healthy controls. Interestingly, these differences were not associated with increased local cytokine levels, putting in evidence that neuropeptide release occurred independently of microglia activation and may be a pivotal alarm system to initiate neurologic reactions to distant inflammatory non-infectious aggression.
Assuntos
Encéfalo/metabolismo , Neuropeptídeos/metabolismo , Pancreatite/metabolismo , Animais , Encéfalo/imunologia , Encéfalo/patologia , Masculino , Neuropeptídeos/imunologia , Pancreatite/imunologia , Pancreatite/patologia , Ratos , Ratos WistarRESUMO
INTRODUCTION: Status epilepticus increases the production of new neurons (hippocampal neurogenesis) and promotes aberrant migration. However chronic experimental models of epilepsy and studies performed in human epilepsy showed controversial results suggesting a reduction in hippocampal neurogenesis in late stages of the disease. Doublecortin (DCX) has been validated to determine alterations in the production of new neurons in the human hippocampus. OBJECTIVES: Determine DCX expression in human hippocampal sclerosis (HS) from patients who underwent epilepsy surgery for refractory temporal lobe epilepsy (TLE). METHODS: Hippocampal sections of 9 patients with HS and TLE who underwent surgery, were processed using immunoperoxidase for DCX. Archival material from 5 normal post-mortem hippocampus were simultaneously processed. RESULTS: Significantly lower staining intensity was observed in DCX-positive neurons localized in dentate gyrus (DG) and in CA1 of epileptic hippocampus; lower DCX reactive area was observed in pyramidal layers of CA1; and a reduced in the mean number of DCX-positive neurons were determined in DG compared to normal hippocampus (p<0.05). CONCLUSIONS: This study found a decrease in DCX expression in hippocampus of patients with HS and chronic and refractory TLE suggesting alterations in NG and hippocampal synaptogenesis with potential cognitive and emotional repercussion.
Assuntos
Epilepsia do Lobo Temporal/patologia , Hipocampo/patologia , Proteínas Associadas aos Microtúbulos/imunologia , Neuropeptídeos/imunologia , Adulto , Giro Denteado/patologia , Proteínas do Domínio Duplacortina , Proteína Duplacortina , Epilepsia do Lobo Temporal/tratamento farmacológico , Epilepsia do Lobo Temporal/imunologia , Epilepsia do Lobo Temporal/cirurgia , Feminino , Hipocampo/imunologia , Hipocampo/fisiopatologia , Humanos , Técnicas Imunoenzimáticas , Masculino , Proteínas Associadas aos Microtúbulos/fisiologia , Neuropeptídeos/fisiologia , EscleroseRESUMO
Lipid peroxidation (LP) is one of the most harmful mechanisms developed after spinal cord (SC) injury. Several strategies have been explored in order to control this phenomenon. Protective autoimmunity is a physiological process based on the modulation of inflammatory cells that can be boosted by immunizing with neural-derived peptides, such as A91. Since inflammatory cells are among the main contributors to lipid peroxidation, we hypothesized that protective autoimmunity could reduce LP after SC injury. In order to test this hypothesis, we designed two experiments in SC contused rats. First, animals were immunized with a neural-derived peptide seven days before injury. With the aim of inducing the functional elimination of CNS-specific T cells, for the second experiment, animals were tolerized against SC-protein extract and thereafter subjected to a SC injury. The lipid-soluble fluorescent products were used as an index of lipid peroxidation and were assessed after injury. Immunization with neural-derived peptides reduced lipid peroxidation after SC injury. Functional elimination of CNS-specific T cells avoided the beneficial effect induced by protective autoimmunity. The present study demonstrates the beneficial effect of immunizing with neural-derived peptides on lipid peroxidation inhibition; besides this, it also provides evidence on the neuroprotective mechanisms exerted by protective autoimmunity.
Assuntos
Peroxidação de Lipídeos , Proteína Básica da Mielina/uso terapêutico , Neuropeptídeos/uso terapêutico , Ovalbumina/uso terapêutico , Traumatismos da Medula Espinal/prevenção & controle , Animais , Autoimunidade , Imunização , Proteína Básica da Mielina/imunologia , Neuropeptídeos/imunologia , Ovalbumina/imunologia , Ratos , Ratos Sprague-Dawley , Traumatismos da Medula Espinal/imunologia , Traumatismos da Medula Espinal/metabolismo , Linfócitos T/imunologiaRESUMO
Os neuropeptídeos são neurotransmissores relevantes na fisiologia nasal e o conhecimento crescente acerca de seu papel na fisiopatologia de doencas nasais abre novas perspectivas. A sua investigacão na mucosa nasal humana baseia-se em grande parte em marcacão imunológica, método complexo e sujeito a inúmeros fatores de erro. Com o intuito de viabilizar este tipo de pesquisa em nosso meio, um método de imunofluorescência para peptídeo intestinal vasoativo (VIP) na mucosa nasal humana é proposto e avaliado. FORMA DE ESTUDO: Coorte transversal. MATERIAL E MÉTODO: Oito pacientes submetidos a cirurgia funcional do nariz têm um fragmento de mucosa coletado da concha inferior. O tecido foi fixado em solucão de Zamboni (paraformaldeído 4 por cento tamponado e ácido pícrico 0,4 por cento), congelado em nitrogênio líquido e armazenado. Cortes de 14 æm foram realizados e submetidos à reacão de imunofluorescência para VIP (Península Laboratories). As imagens microscópicas foram documentadas em fotografia convencional. A especificidade, sensibilidade e reprodutibilidade de execucão foram avaliadas. A reprodutibilidade de interpretacão de resultados foi avaliada através da comparacão de graus de marcacão (0 a 4) atribuídos às fotos por seis observadores. RESULTADOS: Os resultados mostraram ser o método suficientemente específico, sensível, além de reprodutível em sua execucão. A interpretacão de resultados mostrou depender do perfeito esclarecimento do observador no julgamento das imagens de imunofluorescência, mas mostrou uniformidade. CONCLUSAO: O método proposto foi considerado útil na pesquisa de neuropeptídeos na mucosa nasal humana.
Assuntos
Humanos , Imunofluorescência/métodos , Mucosa Nasal/imunologia , Neuropeptídeos/imunologia , Peptídeo Intestinal Vasoativo/imunologia , Estudos Transversais , Sensibilidade e EspecificidadeRESUMO
UNLABELLED: Neuropeptides are important neurotransmitters in nasal physiology and the increasing knowledge of their role in nasal diseases brings new therapeutic perspectives. The investigation of human nasal mucosa neuropeptides is based mostly on immunocytochemistry, a complex approach whose resulting factors may be variable. Aiming to make this kind of research available, an immunofluorescence approach for vasoactive intestinal peptide (VIP) in human nasal mucosa is proposed and evaluated. STUDY DESIGN: Transversal cohort. MATERIAL AND METHOD: Human inferior turbinate samples were obtained at time of nasal surgery from eight patients. The samples were fixed in Zamboni solution (4% phosphate-buffered paraformaldehyde and 0.4% picric acid), snap-frozen and stored at -70 degrees C. 14 microm sections were then obtained. Immunofluorescence staining for VIP (Peninsula Laboratories) was performed and its images documented by conventional photography. The method's specificity, sensitivity and reproducibility of execution were evaluated. Additionally, the reproducibility of interpretation of results was evaluated through the comparison of staining scores (0 to 4) attributed to the images by six observers. RESULTS: The results showed the approach to be very specific and sensible, besides being reproducible in its execution. The interpretation of results may depend on the observer's accuracy in judging immunofluorescence images, but it showed uniformity. CONCLUSION: The proposed method was highly useful for research purposes in neuropeptides in human nasal mucosa.
Assuntos
Imunofluorescência/métodos , Mucosa Nasal/química , Peptídeo Intestinal Vasoativo/análise , Estudos Transversais , Humanos , Neuropeptídeos/análise , Neuropeptídeos/imunologia , Sensibilidade e Especificidade , Conchas Nasais/químicaRESUMO
We studied the innervation of the cat testis using a panel of antisera against the following neuronal markers: protein gene product 9.5 (PGP), neuropeptide Y, C-terminal peptide of neuropeptide Y, galanin, vasoactive intestinal peptide (VIP), calcitonin gene-related peptide, and substance P. Immunoreactivity against PGP, a general neuronal label, demonstrated the arrangement of fibers from the superior spermatic nerve (SSN) in the testicular pedicle and the cephalic testicular pole, and those of the inferior spermatic nerve (ISN) along the vas deferens and the inferior testicular ligament. The testicular parenchyma exhibited a very rich innervation, mainly distributed to blood vessels and Leydig cell nests, but also in close association with seminiferous tubules. Numerous peptidergic fibers were present in the SSN and ISN, albeit in different proportions. Thus, VIP-immunoreactive fibers were almost absent in the SSN, but were the most abundant subpopulation of the ISN. The testicular interstitium contained numerous peptidergic fibers, associated with blood vessels, interstitial Leydig cells, and seminiferous tubules. Similar fibers were related to the rete testis. Parenchymatous VIP-immunoreactive nerves disappeared after bilateral vasectomy. Stimulation of the ISN under experimental conditions was associated with an increase of blood flow, and induced a large release of VIP into the spermatic vein. The extensive and selective distribution of nerve fibers within the cat testicular parenchyma supports the importance of spermatic nerves for testicular function. Furthermore, the differences in the fiber composition of the SSN and ISN can be correlated with their opposing effects on testosterone secretion and testicular blood flow.