RESUMEN
Rostral agranular insular cortex (RAIC) projects to periaqueductal gray (PAG) and inhibits spinal nociceptive transmission by activating PAG-rostral ventromedial medulla (RVM) descending antinociceptive circuitry. Despite being generated from the same precursor prepronociceptin, nocistatin (NST) and nociceptin/orphanin FQ (N/OFQ) produce supraspinal analgesic and hyperalgesic effects, respectively. Prepronociceptin is highly expressed in the RAIC. In the present study, we hypothesized that NST and N/OFQ modulate spinal pain transmission by regulating the activity of RAIC neurons projecting to ventrolateral PAG (RAIC-PAG). This hypothesis was tested by investigating electrophysiological effects of N/OFQ and NST on RAIC-PAG projection neurons in brain slice. Retrogradely labeled RAIC-PAG projection neurons are layer V pyramidal cells and express mRNA of vesicular glutamate transporter subtype 1, a marker for glutamatergic neurons. N/OFQ hyperpolarized 25% of RAIC-PAG pyramidal neurons by enhancing inwardly rectifying potassium conductance via pertussis toxin-sensitive G(alphai/o). In contrast, NST depolarized 33% of RAIC-PAG glutamatergic neurons by causing the opening of canonical transient receptor potential (TRPC) cation channels through G(alphaq/11)-phospholipase C-protein kinase C pathway. There were two separate populations of RAIC-PAG pyramidal neurons, one responding to NST and the other one to N/OFQ. Our results suggest that G(alphaq/11)-coupled NST receptor mediates NST excitation of RAIC-PAG glutamatergic neurons, which is expected to cause the supraspinal analgesia by enhancing the activity of RAIC-PAG-RVM antinociceptive pathway. Opposite effects of NST and N/OFQ on supraspinal pain regulation are likely to result from their opposing effects on RAIC-PAG pyramidal neurons.
Asunto(s)
Corteza Cerebral/fisiología , Subunidades alfa de la Proteína de Unión al GTP Gq-G11/fisiología , Péptidos Opioides/fisiología , Sustancia Gris Periacueductal/fisiología , Proteína Quinasa C/fisiología , Células Piramidales/fisiología , Canales Catiónicos TRPC/fisiología , Fosfolipasas de Tipo C/fisiología , Animales , Corteza Cerebral/citología , Técnicas In Vitro , Bulbo Raquídeo/fisiología , Sustancia Gris Periacueductal/citología , Canales de Potasio de Rectificación Interna/fisiología , Ratas , Ratas Sprague-Dawley , Receptores Opioides/biosíntesis , Transducción de Señal , NociceptinaRESUMEN
TNF-related apoptosis-inducing ligand (TRAIL, also called Apo2L), a novel member of TNF superfamily, induces apoptosis in transformed cell lines of diverse origin. TRAIL is expressed in most of the cells, and the expression is up-regulated in activated T cells. Four receptors for TRAIL have been identified, and there is complex interplay between TRAIL and TRAIL receptors in vivo. The actual biological function of TRAIL/TRAIL receptor is still not clear. Growing evidence has demonstrated that members of TNF superfamily transduce signals after engagement with their receptors. Cross-linking of TRAIL by plate-bound rTRAIL receptor, death receptor 4-Fc fusion protein enhanced T cell proliferation and increased IFN-gamma production in conjunction with immobilized suboptimal anti-CD3 stimulation in mouse splenocytes. The increase of T cell proliferation by death receptor 4-Fc was dose dependent, and this effect could be blocked by soluble rTRAIL proteins, indicating the occurrence of reverse signaling through TRAIL on T cell. The enhanced secretion of IFN-gamma mediated via TRAIL could be blocked by SB203580, a p38 mitogen-activated protein kinase-specific inhibitor. Thus, in addition to its role in inducing apoptosis by binding to the death receptors, TRAIL itself can enhance T cell proliferation after TCR engagement and signal the augmentation of IFN-gamma secretion via a p38-dependent pathway. This provides another example of reverse signaling by a member of TNF superfamily. In conclusion, our data suggest that TRAIL can itself transduce a reverse signal, and this may shed light on the biological function of TRAIL.
Asunto(s)
Apoptosis/inmunología , Interferón gamma/biosíntesis , Activación de Linfocitos , Glicoproteínas de Membrana/fisiología , Transducción de Señal/inmunología , Linfocitos T/inmunología , Linfocitos T/metabolismo , Factor de Necrosis Tumoral alfa/fisiología , Animales , Anticuerpos Monoclonales/farmacología , Apoptosis/genética , Proteínas Reguladoras de la Apoptosis , Complejo CD3/inmunología , Células Cultivadas , Inhibidores Enzimáticos/farmacología , Humanos , Imidazoles/farmacología , Fragmentos Fc de Inmunoglobulinas/genética , Fragmentos Fc de Inmunoglobulinas/metabolismo , Interferón gamma/antagonistas & inhibidores , Interferón gamma/metabolismo , Ligandos , Activación de Linfocitos/genética , Glicoproteínas de Membrana/biosíntesis , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Ratones , Proteínas Quinasas Activadas por Mitógenos/antagonistas & inhibidores , Piridinas/farmacología , Receptores del Ligando Inductor de Apoptosis Relacionado con TNF , Receptores del Factor de Necrosis Tumoral/genética , Receptores del Factor de Necrosis Tumoral/metabolismo , Proteínas Recombinantes de Fusión/inmunología , Proteínas Recombinantes de Fusión/metabolismo , Transducción de Señal/genética , Linfocitos T/enzimología , Ligando Inductor de Apoptosis Relacionado con TNF , Factor de Necrosis Tumoral alfa/biosíntesis , Factor de Necrosis Tumoral alfa/genética , Factor de Necrosis Tumoral alfa/metabolismo , Regulación hacia Arriba/efectos de los fármacos , Regulación hacia Arriba/inmunología , Proteínas Quinasas p38 Activadas por MitógenosRESUMEN
The vertebrate Wnt-1 proto-oncogene is expressed transiently in embryonic brain and functions in the development of the central nervous system and neural crest. The role of Wnt-1 in neural crest development appears to be to increase the number of certain progenitor cells by preventing their premature differentiation. To study the mechanism by which this transient Wnt-1 expression inhibits differentiation we have constructed PC12 pheochromocytoma cells in which Wnt-1 expression levels were controlled by use of a tetracycline-responsive transactivator. Induction of Wnt-1 expression by tetracycline withdrawal was followed by activation of the Wnt-1 signalling pathway as shown by activation of the Lef-1/Tcf transcription factor. Wnt-1 expression by these cells resulted in reversible inhibition of NGF-induced neurite outgrowth, but it did not adversely affect the maintenance of previously formed NGF-induced neurites. Wnt-1 expression also partially blocked the ability of NGF to decrease the rate of cell multiplication. Wnt-1 decreased the NGF-induced expression of the late-response gene SCG10 but not of the immediate early genes, fos, Nur77 and UPAR (urokinase-type plasminogen activator receptor) nor of the late-response genes GAP-43 and collagenase. The Wnt-1 expressing PC12 cells multiplied at a greater rate when they expressed Wnt-1 than they did in the absence of Wnt-1 expression, a result that is consistent with the proposal that Wnt-1 may also act as a mitogen.
Asunto(s)
Regulación de la Expresión Génica , Factor de Crecimiento Nervioso/antagonistas & inhibidores , Neuritas/metabolismo , Proteínas Proto-Oncogénicas/fisiología , Proteínas de Pez Cebra , Transportadoras de Casetes de Unión a ATP/metabolismo , Sistema de Transporte de Aminoácidos X-AG , Animales , Proteínas de Unión al Calcio , Proteínas Portadoras , Diferenciación Celular/efectos de los fármacos , División Celular/efectos de los fármacos , Tamaño de la Célula/efectos de los fármacos , Proteínas de Unión al ADN/metabolismo , Receptores Frizzled , Proteína GAP-43/genética , Regulación de la Expresión Génica/efectos de los fármacos , Genes Inmediatos-Precoces/genética , Ácido Glutámico/metabolismo , Péptidos y Proteínas de Señalización Intracelular , Factor de Unión 1 al Potenciador Linfoide , Proteínas de la Membrana , Ratones , Proteínas de Microtúbulos , Factor de Crecimiento Nervioso/farmacología , Factores de Crecimiento Nervioso/genética , Neuritas/efectos de los fármacos , Células PC12 , Proteínas/genética , Proteínas Proto-Oncogénicas/genética , ARN Mensajero/genética , ARN Mensajero/metabolismo , Ratas , Receptores de Superficie Celular/genética , Receptores del Activador de Plasminógeno Tipo Uroquinasa , Transducción de Señal/efectos de los fármacos , Estatmina , Tetraciclina/farmacología , Factores de Transcripción/metabolismo , Transcripción Genética/efectos de los fármacos , Transcripción Genética/genética , Tirosina 3-Monooxigenasa/genética , Proteínas Wnt , Proteína Wnt1RESUMEN
BACKGROUND: IgE-mediated hypersensitivity is a suggested mechanism to explain adverse reactions from carmine-containing products. OBJECTIVE: To describe a patient who experienced anaphylaxis after ingestion of a popsicle colored with carmine and to provide additional evidence that the adverse reaction was IgE-mediated. METHODS: The patient and her husband underwent skin prick tests to the popsicle and carmine. The patient also received skin prick tests and/or open oral challenge to each of the other components of the incriminated food. Topical application of cosmetics with and without carmine to the patient's forearm was also performed. To confirm carmine-specific IgE, a Prausnitz-Kustner (P-K) test was performed using the patient's husband as recipient. Twenty control subjects also were tested to carmine by skin prick test. RESULTS: The patient showed 4+ skin prick test responses to the popsicle and carmine. Skin prick tests and/or open oral challenge to each of the other components of the popsicle were negative. The patient's husband's and 20 control subjects' skin prick tests to carmine were negative as was the patient's husband's skin prick test to the popsicle. Skin prick test reactivity to the popsicle and carmine were successfully transferred to the patient's husband in P-K format. Cosmetics applied to the patient's forearm elicited no immediate response. CONCLUSION: The positive skin prick tests to the popsicle and carmine and the successful (P-K) transfer of skin prick test reactivity support a carmine-specific, IgE-mediated mechanism in explaining our patient's popsicle-induced anaphylaxis.