RESUMEN
Substance use disorder (SUD) is a chronic relapsing disorder characterized by transitioning from acute drug reward to compulsive drug use. Despite the heavy personal and societal burden of SUDs, current treatments are limited and unsatisfactory. For this reason, a deeper understanding of the mechanisms underlying addiction is required. Altered redox status, primarily due to drug-induced increases in dopamine metabolism, is a unifying feature of abused substances. In recent years, knowledge of the effects of oxidative stress in the nervous system has evolved from strictly neurotoxic to include a more nuanced role in redox-sensitive signaling. More specifically, S-glutathionylation, a redox-sensitive post-translational modification, has been suggested to influence the response to drugs of abuse. In this review we will examine the evidence for redox-mediating drugs as therapeutic tools focusing on N-acetylcysteine as a treatment for cocaine addiction. We will conclude by suggesting future research directions that may further advance this field.
Asunto(s)
Acetilcisteína/administración & dosificación , Acetilcisteína/metabolismo , Sistemas de Liberación de Medicamentos/métodos , Estrés Oxidativo/efectos de los fármacos , Trastornos Relacionados con Sustancias/tratamiento farmacológico , Trastornos Relacionados con Sustancias/metabolismo , Animales , Trastornos Relacionados con Cocaína/metabolismo , Sistemas de Liberación de Medicamentos/tendencias , Glutatión/análogos & derivados , Glutatión/antagonistas & inhibidores , Glutatión/metabolismo , Humanos , Oxidación-Reducción/efectos de los fármacos , Estrés Oxidativo/fisiología , Especies Reactivas de Oxígeno/antagonistas & inhibidores , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Cognitive impairments, uncontrolled drinking, and neuropathological cortical changes characterize alcohol use disorder. Dysfunction of the orbitofrontal cortex (OFC), a critical cortical subregion that controls learning, decision-making, and prediction of reward outcomes, contributes to executive cognitive function deficits in alcoholic individuals. Electrophysiological and quantitative synaptomics techniques were used to test the hypothesis that heavy drinking produces neuroadaptations in the macaque OFC. Integrative bioinformatics and reverse genetic approaches were used to identify and validate synaptic proteins with novel links to heavy drinking in BXD mice. In drinking monkeys, evoked firing of OFC pyramidal neurons was reduced, whereas the amplitude and frequency of postsynaptic currents were enhanced compared with controls. Bath application of alcohol reduced evoked firing in neurons from control monkeys, but not drinking monkeys. Profiling of the OFC synaptome identified alcohol-sensitive proteins that control glutamate release (e.g., SV2A, synaptogyrin-1) and postsynaptic signaling (e.g., GluA1, PRRT2) with no changes in synaptic GABAergic proteins. Western blot analysis confirmed the increase in GluA1 expression in drinking monkeys. An exploratory analysis of the OFC synaptome found cross-species genetic links to alcohol intake in discrete proteins (e.g., C2CD2L, DIRAS2) that discriminated between low- and heavy-drinking monkeys. Validation studies revealed that BXD mouse strains with the D allele at the C2cd2l interval drank less alcohol than B allele strains. Thus, by profiling of the OFC synaptome, we identified changes in proteins controlling glutamate release and postsynaptic signaling and discovered several proteins related to heavy drinking that have potential as novel targets for treating alcohol use disorder.SIGNIFICANCE STATEMENT Clinical research identified cognitive deficits in alcoholic individuals as a risk factor for relapse, and alcoholic individuals display deficits on cognitive tasks that are dependent upon the orbitofrontal cortex (OFC). To identify neurobiological mechanisms that underpin OFC dysfunction, this study used electrophysiology and integrative synaptomics in a translational nonhuman primate model of heavy alcohol consumption. We found adaptations in synaptic proteins that control glutamatergic signaling in chronically drinking monkeys. Our functional genomic exploratory analyses identified proteins with genetic links to alcohol and cocaine intake across mice, monkeys, and humans. Future work is necessary to determine whether targeting these novel targets reduces excessive and harmful levels of alcohol drinking.
Asunto(s)
Adaptación Fisiológica , Alcoholismo/metabolismo , Proteínas del Tejido Nervioso/metabolismo , Plasticidad Neuronal , Corteza Prefrontal/metabolismo , Sinapsis/metabolismo , Alcoholismo/patología , Animales , Biomarcadores/metabolismo , Macaca fascicularis , Masculino , Corteza Prefrontal/patología , Sinapsis/patologíaRESUMEN
Sphingosine-1-phosphate (S1P) is a biologically active sphingolipid metabolite which has been implicated in many diseases including cancer and inflammatory diseases. Recently, sphingosine kinase 1 (SK1), one of the isozymes which generates S1P, has been implicated in the development and progression of inflammatory bowel disease (IBD). Based on our previous work, we set out to determine the efficacy of a novel SK1 selective inhibitor, LCL351, in a murine model of IBD. LCL351 selectively inhibits SK1 both in vitro and in cells. LCL351, which accumulates in relevant tissues such as colon, did not have any adverse side effects in vivo. In mice challenged with dextran sodium sulfate (DSS), a murine model for IBD, LCL351 treatment protected from blood loss and splenomegaly. Additionally, LCL351 treatment reduced the expression of pro-inflammatory markers, and reduced neutrophil infiltration in colon tissue. Our results suggest inflammation associated with IBD can be targeted pharmacologically through the inhibition and degradation of SK1. Furthermore, our data also identifies desirable properties of SK1 inhibitors.
Asunto(s)
Colitis/tratamiento farmacológico , Colitis/inmunología , Sulfato de Dextran/efectos adversos , Guanidinas/farmacología , Fosfotransferasas (Aceptor de Grupo Alcohol)/antagonistas & inhibidores , Esfingosina/farmacología , Células A549 , Quimiocina CXCL1/genética , Quimiocina CXCL2/genética , Colitis/inducido químicamente , Colitis/genética , Regulación de la Expresión Génica/efectos de los fármacos , Regulación de la Expresión Génica/inmunología , Guanidinas/uso terapéutico , Humanos , Esfingosina/uso terapéutico , Factor de Necrosis Tumoral alfa/genéticaRESUMEN
Alcohol use disorder is a chronic relapsing brain disease characterized by the loss of ability to control alcohol (ethanol) intake despite knowledge of detrimental health or personal consequences. Clinical and pre-clinical models provide strong evidence for chronic ethanol-associated alterations in glutamatergic signaling and impaired synaptic plasticity in the nucleus accumbens (NAc). However, the neural mechanisms that contribute to aberrant glutamatergic signaling in ethanol-dependent individuals in this critical brain structure remain unknown. Using an unbiased proteomic approach, we investigated the effects of chronic intermittent ethanol (CIE) exposure on neuroadaptations in postsynaptic density (PSD)-enriched proteins in the NAc of ethanol-dependent mice. Compared with controls, CIE exposure significantly changed expression levels of 50 proteins in the PSD-enriched fraction. Systems biology and functional annotation analyses demonstrated that the dysregulated proteins are expressed at tetrapartite synapses and critically regulate cellular morphology. To confirm this latter finding, the density and morphology of dendritic spines were examined in the NAc core of ethanol-dependent mice. We found that CIE exposure and withdrawal differentially altered dendrite diameter and dendritic spine density and morphology. Through the use of quantitative proteomics and functional annotation, these series of experiments demonstrate that ethanol dependence produces neuroadaptations in proteins that modify dendritic spine morphology. In addition, these studies identified novel PSD-related proteins that contribute to the neurobiological mechanisms of ethanol dependence that drive maladaptive structural plasticity of NAc neurons.
Asunto(s)
Alcoholismo/metabolismo , Depresores del Sistema Nervioso Central/farmacología , Espinas Dendríticas/efectos de los fármacos , Etanol/farmacología , Núcleo Accumbens/efectos de los fármacos , Densidad Postsináptica/efectos de los fármacos , Proteoma/efectos de los fármacos , Animales , Western Blotting , Depresores del Sistema Nervioso Central/administración & dosificación , Cromatografía Liquida , Espinas Dendríticas/metabolismo , Modelos Animales de Enfermedad , Etanol/administración & dosificación , Masculino , Ratones , Núcleo Accumbens/metabolismo , Densidad Postsináptica/metabolismo , Proteoma/metabolismo , Síndrome de Abstinencia a Sustancias/etiología , Síndrome de Abstinencia a Sustancias/metabolismo , Espectrometría de Masas en TándemRESUMEN
To identify candidate proteins in the nucleus accumbens (NAc) as potential pharmacotherapeutic targets for treating cocaine addition, an 8-plex iTRAQ (isobaric tag for relative and absolute quantitation) proteomic screen was performed using NAc tissue obtained from rats trained to self-administer cocaine followed by extinction training. Compared with yoked-saline controls, 42 proteins in a postsynaptic density (PSD)-enriched subfraction of the NAc from cocaine-trained animals were identified as significantly changed. Among proteins of interest whose levels were identified as increased was AKAP79/150, the rat ortholog of human AKAP5, a PSD scaffolding protein that localizes signaling molecules to the synapse. Functional downregulation of AKAP79/150 by microinjecting a cell-permeable synthetic AKAP (A-kinase anchor protein) peptide into the NAc to disrupt AKAP-dependent signaling revealed that inhibition of AKAP signaling impaired the reinstatement of cocaine seeking. Reinstatement of cocaine seeking is thought to require upregulated surface expression of AMPA glutamate receptors, and the inhibitory AKAP peptide reduced the PSD content of protein kinase A (PKA) as well as surface expression of GluR1 in NAc. However, reduced surface expression was not associated with changes in PKA phosphorylation of GluR1. This series of experiments demonstrates that proteomic analysis provides a useful tool for identifying proteins that can regulate cocaine relapse and that AKAP proteins may contribute to relapse vulnerability by promoting increased surface expression of AMPA receptors in the NAc.
Asunto(s)
Proteínas de Anclaje a la Quinasa A/fisiología , Trastornos Relacionados con Cocaína/psicología , Proteómica/métodos , Transducción de Señal/efectos de los fármacos , Secuencia de Aminoácidos , Animales , Conducta Animal/efectos de los fármacos , Conducta Animal/fisiología , Western Blotting , Cromatografía Líquida de Alta Presión , Cromatografía por Intercambio Iónico , Proteínas Quinasas Dependientes de AMP Cíclico/fisiología , Masculino , Datos de Secuencia Molecular , Proteínas del Tejido Nervioso/biosíntesis , Proteínas del Tejido Nervioso/genética , Redes Neurales de la Computación , Núcleo Accumbens/fisiología , Ratas , Ratas Sprague-Dawley , Receptores AMPA/biosíntesis , Receptores AMPA/genética , Autoadministración , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Fracciones Subcelulares/efectos de los fármacos , Fracciones Subcelulares/metabolismo , Sinapsis/fisiologíaRESUMEN
Neuronal defense against oxidative damage is mediated primarily by the glutathione redox system. Traditionally considered a mechanism to protect proteins from irreversible oxidation, mounting evidence supports a role for protein S-glutathionylation in cell signaling in response to changes in intracellular redox status. Here we determined the specific sites on the actin binding protein cofilin that undergo S-glutathionylation. In addition, we show that S-glutathionylation of cofilin reduces its capacity to depolymerize F-actin. We further describe an assay to determine the S-glutathionylation of target proteins in brain tissue from behaving rodents. Using this technique, we show that cofilin in the rat nucleus accumbens undergoes S-glutathionylation during 15-minutes of cued cocaine seeking in the absence of cocaine. Our findings demonstrate that cofilin S-glutathionylation is increased in response to cocaine-associated cues and that increased cofilin S-glutathionylation reduces cofilin-dependent depolymerization of F-actin. Thus, S-glutathionylation of cofilin may serve to regulate actin cycling in response to drug-conditioned cues.
Asunto(s)
Factores Despolimerizantes de la Actina/metabolismo , Actinas/metabolismo , Comportamiento de Búsqueda de Drogas/fisiología , Glutatión/metabolismo , Núcleo Accumbens/fisiología , Animales , Conducta Animal/fisiología , Cocaína/administración & dosificación , Condicionamiento Operante/efectos de los fármacos , Condicionamiento Operante/fisiología , Señales (Psicología) , Masculino , Modelos Animales , Núcleo Accumbens/efectos de los fármacos , Oxidación-Reducción/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Estrés Oxidativo/fisiología , Procesamiento Proteico-Postraduccional/efectos de los fármacos , Procesamiento Proteico-Postraduccional/fisiología , Ratas , Autoadministración/psicologíaRESUMEN
Early life traumatic experiences are associated with psychopathology in adulthood. This may be due in part to the effects of trauma on hippocampal development and protein expression. The purpose of the study was to investigate the effects of early life trauma and adult re-stress on ventral hippocampal protein expression. Adolescent rats (n = 19) were subjected to a triple stressor on post-natal day 28 followed 7 days later by the first re-stress session and 25 days later (post-natal day 60 = adulthood) by the second re-stress session. Ventral hippocampi were collected on post-natal day 68 for protein expression determinations using protein arrays and 2D-gel electrophoresis with liquid chromatography tandem mass spectrometry. Compared to controls, traumatized animals showed an increase in Ca(2+) homeostatic proteins, dysregulated signaling pathways and energy metabolism enzymes, cytoskeletal protein changes, a decrease in neuroplasticity regulators, energy metabolism enzymes and an increase in apoptotic initiator proteins. These results indicate the extensive impact of trauma on adult brain development and behavior.
Asunto(s)
Hipocampo , Trastornos Mentales , Proteoma/análisis , Estrés Psicológico , Adulto , Animales , Encéfalo/fisiología , Hipocampo/metabolismo , Hipocampo/patología , Humanos , Masculino , Trastornos Mentales/etiología , Trastornos Mentales/fisiopatología , Datos de Secuencia Molecular , Análisis por Matrices de Proteínas , Ratas , Ratas Sprague-Dawley , Estrés Psicológico/complicaciones , Estrés Psicológico/psicologíaRESUMEN
Methamphetamine (METH) is a drug with a high addictive potential that is widely abused across the world. Although it is known that METH dysregulates both dopamine transmission and dopamine reuptake, the specific mechanism of action remains obscure. One promising target of METH is the sigma receptor, a chaperone protein located on the membrane of the endoplasmic reticulum. Using fast-scan cyclic voltammetry, we show that METH-enhancement of evoked dopamine release and basal efflux is dependent on sigma receptor activation. METH-induced activation of sigma receptors results in oxidation of a cysteine residue on VMAT2, which decreases transporter function. Unilateral injections of the sigma receptor antagonist BD-1063 prior to METH administration increased dopamine-related ipsilateral circling behavior, indicating the involvement of sigma receptors. These findings suggest that interactions between METH and the sigma receptor lead to oxidative species (most likely superoxide) that in turn oxidize VMAT2. Altogether, these findings show that the sigma receptor has a key role in METH dysregulation of dopamine release and dopamine-related behaviors.
Asunto(s)
Estimulantes del Sistema Nervioso Central/farmacología , Dopamina/metabolismo , Metanfetamina/farmacología , Núcleo Accumbens/efectos de los fármacos , Núcleo Accumbens/metabolismo , Receptores sigma/metabolismo , Trastornos Relacionados con Anfetaminas/metabolismo , Animales , Antioxidantes/farmacología , Dopaminérgicos/farmacología , Masculino , Ratones Endogámicos C57BL , Actividad Motora/efectos de los fármacos , Ratas Wistar , Especies Reactivas de Oxígeno/metabolismo , Receptores sigma/antagonistas & inhibidores , Técnicas de Cultivo de Tejidos , Proteínas de Transporte Vesicular de Monoaminas/metabolismoRESUMEN
Effects of early-life trauma on adult behavioral responses, corticosterone (CORT) concentration, and levels of nerve growth factor (NGF), brain-derived neutrophic factor (BDNF), and neurotrophin-3 (NT-3) in hippocampus and frontal cortex were investigated. Traumatized animals showed an increase in rearing in both the elevated plus maze and open field after adult restress, higher basal levels of CORT, lower levels of BDNF in dorsal hippocampus, and lower levels of NT-3 in dorsal and ventral hippocampus. Trauma-related behavioral hyperarousal and altered hypothalamic-pituitary-adrenal (HPA) axis activity may be mediated by decreases in hippocampal neurotrophin expression.
Asunto(s)
Animales Recién Nacidos/fisiología , Nivel de Alerta/fisiología , Conducta Animal/fisiología , Hipocampo/metabolismo , Sistema Hipotálamo-Hipofisario/fisiopatología , Factores de Crecimiento Nervioso/biosíntesis , Heridas y Lesiones/fisiopatología , Heridas y Lesiones/psicología , Animales , Factor Neurotrófico Derivado del Encéfalo/biosíntesis , Masculino , Neurotrofina 3/biosíntesis , Ratas , Ratas Sprague-Dawley , Heridas y Lesiones/metabolismoRESUMEN
Drug addiction is a chronic relapsing disorder that comes at a high cost to individuals and society. Therefore understanding the mechanisms by which drugs exert their effects is of prime importance. Drugs of abuse increase the production of reactive oxygen and nitrogen species resulting in oxidative stress. This change in redox homeostasis increases the conjugation of glutathione to protein cysteine residues; a process called S-glutathionylation. Although traditionally regarded as a protective mechanism against irreversible protein oxidation, accumulated evidence suggests a more nuanced role for S-glutathionylation, namely as a mediator in redox-sensitive protein signaling. The reversible modification of protein thiols leading to alteration in function under different physiologic/pathologic conditions provides a mechanism whereby change in redox status can be translated into a functional response. As such, S-glutathionylation represents an understudied means of post-translational protein modification that may be important in the mechanisms underlying drug addiction. This review will discuss the evidence for S-glutathionylation as a redox-sensing mechanism and how this may be involved in the response to drug-induced oxidative stress. The function of S-glutathionylated proteins involved in neurotransmission, dendritic spine structure, and drug-induced behavioral outputs will be reviewed with specific reference to alcohol, cocaine, and heroin.
Asunto(s)
Glutatión/metabolismo , Transducción de Señal , Trastornos Relacionados con Sustancias/metabolismo , Humanos , Oxidación-ReducciónRESUMEN
Epidemiological studies show that the use of club drugs is on the rise. Furthermore, the last few decades have seen a rise in patterns of polydrug use. One of the combinations frequently used is ecstasy (MDMA) with gammahydroxybutyrate (GHB). For effective prevention it is important to be aware of this phenomenon and of the pharmacology of these drugs. The effects of the combination extend to different neurotransmitter systems, including serotonin, dopamine and noradrenaline. Studies investigating the effects of combinations of psychoactive substances are limited. In this review we describe the subjective effects of the MDMA/GHB combination. Furthermore, we review the individual actions of MDMA on serotonin, dopamine and noradrenaline systems. In addition, actions of GHB on these systems are discussed as a possible pharmacological basis for the interaction of both drugs. It is postulated that GHB attenuates the unpleasant or dysphoric effects of MDMA by its effect on the central dopaminergic system.
Asunto(s)
Dopamina/metabolismo , Alucinógenos/efectos adversos , Hidroxibutiratos/farmacología , N-Metil-3,4-metilenodioxianfetamina/efectos adversos , Norepinefrina/metabolismo , Serotonina/metabolismo , Trastornos Relacionados con Sustancias , Ansiedad/inducido químicamente , Temperatura Corporal/efectos de los fármacos , Depresión/inducido químicamente , Humanos , Trastornos Psicomotores/inducido químicamenteRESUMEN
Throughout the last couple decades, the cause and consequences of substance abuse has expanded to identify the underlying neurobiological signaling mechanisms associated with addictive behavior. Chronic use of drugs, such as cocaine, methamphetamine and alcohol leads to the formation of oxidative or nitrosative stress (ROS/RNS) and changes in glutathione and redox homeostasis. Of importance, redox-sensitive post-translational modifications on cysteine residues, such as S-glutathionylation and S-nitrosylation could impact on the structure and function of addiction related signaling proteins. In this commentary, we evaluate the role of glutathione and redox signaling in cocaine-, methamphetamine- and alcohol addiction and conclude by discussing the possibility of targeting redox pathways for the therapeutic intervention of these substance abuse disorders.
Asunto(s)
Glutatión/metabolismo , Estrés Oxidativo/fisiología , Transducción de Señal/fisiología , Trastornos Relacionados con Sustancias/metabolismo , Animales , Glutatión/antagonistas & inhibidores , Humanos , Oxidación-Reducción/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , Especies Reactivas de Oxígeno/metabolismo , Transducción de Señal/efectos de los fármacos , Trastornos Relacionados con Sustancias/tratamiento farmacológicoRESUMEN
First-line therapy for pancreatic cancer is gemcitabine. Although tumors may initially respond to the gemcitabine treatment, soon tumor resistance develops leading to treatment failure. Previously, we demonstrated in human MIA PaCa-2 pancreatic cancer cells that N-acetyl-l-cysteine (NAC), a glutathione (GSH) precursor, prevents NFκB activation via S-glutathionylation of p65-NFκB, thereby blunting expression of survival genes. In this study, we documented the molecular sites of S-glutathionylation of p65, and we investigated whether NAC can suppress NFκB signaling and augment a therapeutic response to gemcitabine in vivo. Mass spectrometric analysis of S-glutathionylated p65-NFκB protein in vitro showed post-translational modifications of cysteines 38, 105, 120, 160 and 216 following oxidative and nitrosative stress. Circular dichroism revealed that S-glutathionylation of p65-NFκB did not change secondary structure of the protein, but increased tryptophan fluorescence revealed altered tertiary structure. Gemcitabine and NAC individually were not effective in decreasing MIA PaCa-2 tumor growth in vivo. However, combination treatment with NAC and gemcitabine decreased tumor growth by approximately 50%. NAC treatment also markedly enhanced tumor apoptosis in gemcitabine-treated mice. Compared to untreated tumors, gemcitabine treatment alone increased p65-NFκB nuclear translocation (3.7-fold) and DNA binding (2.5-fold), and these effects were blunted by NAC. In addition, NAC plus gemcitabine treatment decreased anti-apoptotic XIAP protein expression compared to gemcitabine alone. None of the treatments, however, affected extent of tumor hypoxia, as assessed by EF5 staining. Together, these results indicate that adjunct therapy with NAC prevents NFκB activation and improves gemcitabine chemotherapeutic efficacy.
Asunto(s)
Acetilcisteína/metabolismo , Desoxicitidina/análogos & derivados , FN-kappa B/metabolismo , Neoplasias Pancreáticas/tratamiento farmacológico , Transducción de Señal/efectos de los fármacos , Animales , Apoptosis/efectos de los fármacos , Línea Celular Tumoral , Cisteína/metabolismo , Desoxicitidina/farmacología , Glutatión/metabolismo , Humanos , Masculino , Ratones , Ratones Desnudos , Estrés Oxidativo/efectos de los fármacos , Neoplasias Pancreáticas/metabolismo , Proteína Inhibidora de la Apoptosis Ligada a X/metabolismo , GemcitabinaRESUMEN
Many cancer drugs impact cancer cell redox regulatory mechanisms and disrupt redox homeostasis. Pharmacodynamic biomarkers that measure therapeutic efficacy or toxicity could improve patient management. Using immunoblot analyses and mass spectrometry, we identified that serpins A1 and A3 were S-glutathionylated in a dose- and time-dependent manner following treatment of mice with drugs that alter reactive oxygen or nitrogen species. Tandem mass spectrometry analyses identified Cys(256) of serpin A1 and Cys(263) of serpin A3 as the S-glutathionylated residues. In human plasma from cancer patients, there were higher levels of unmodified serpin A1 and A3, but following treatments with redox active drugs, relative S-glutathionylation of these serpins was higher in plasma from normal individuals. There is potential for S-glutathionylated serpins A1 and A3 to act as pharmacodynamic biomarkers for evaluation of patient response to drugs that target redox pathways.
Asunto(s)
Biomarcadores de Tumor/sangre , Glutatión/análogos & derivados , Neoplasias/sangre , Neoplasias/tratamiento farmacológico , alfa 1-Antiquimotripsina/sangre , alfa 1-Antitripsina/sangre , Animales , Cisplatino/farmacología , Relación Dosis-Respuesta a Droga , Combinación de Medicamentos , Glutatión/sangre , Disulfuro de Glutatión/farmacología , Humanos , Inmunoprecipitación , Ratones , Oxidación-Reducción/efectos de los fármacos , Serpinas/sangre , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción , Espectrometría de Masas en TándemRESUMEN
The ATP-binding cassette transporter 2 (ABCA2) is an endolysosomal protein expressed in oligodendrocytes and Schwann cells, prostate, ovary and macrophages. In cell cultures, ABCA2 over-expression has been linked with resistance to the anticancer agent, estramustine phosphate (EMP; a nor-nitrogen mustard conjugate of estradiol). The present study shows that Abca2 knockout (KO) mice have greater sensitivity to a variety of side effects induced by EMP treatment. Chronic EMP (12×100 mg/kg body weight) produced mortality in 36% of KO mice, but only 7% of age-matched wild type (WT). Side effects of the drug were also more prevalent in the KO mouse. For example, during the first week of EMP treatments, 67% of KO males (compared to 6% of WT males) responded with episodic erectile events. In WT mice, ABCA2 protein localized within pene corpuscles, (which rely on modified Schwann cells for amplification of tactile signals) suggesting that the transporter may function in the erectile process. Endothelial nitric oxide synthase (eNOS; a source of nitric oxide during erectile response) levels were similar in WT and KO male penile tissue. Treatment with 100 mg/kg EMP (once daily for four days) elevated serum estradiol and estrone in both WT and KO. However, the circulating levels of these estrogens were higher in KO mice implying a reduced plasma clearance of estrogens as a consequence of ABCA2 ablation. Consistent with the pro-convulsant effects of estrogens, KO mice also displayed an increased incidence of seizures following EMP (14% vs. 0%). Taken together, these data indicate that ABCA2 deficiency renders mice more sensitive to EMP treatment-induced effects implying that the transporter has a role in regulating EMP transport and/or metabolism.
Asunto(s)
Transportadoras de Casetes de Unión a ATP/metabolismo , Estramustina/efectos adversos , Estrógenos/efectos adversos , Mucositis/inducido químicamente , Pene/efectos de los fármacos , Convulsiones/inducido químicamente , Disfunciones Sexuales Fisiológicas/inducido químicamente , Transportadoras de Casetes de Unión a ATP/genética , Animales , Biotransformación , Susceptibilidad a Enfermedades , Estradiol/sangre , Estramustina/sangre , Estramustina/farmacocinética , Estramustina/uso terapéutico , Estrógenos/sangre , Estrógenos/farmacocinética , Estrógenos/uso terapéutico , Estrona/sangre , Femenino , Mucosa Gástrica/efectos de los fármacos , Mucosa Gástrica/patología , Mucosa Intestinal/efectos de los fármacos , Mucosa Intestinal/patología , Masculino , Tasa de Depuración Metabólica , Ratones , Ratones Noqueados , Mucositis/patología , Óxido Nítrico Sintasa de Tipo III/metabolismo , Erección Peniana/efectos de los fármacos , Pene/metabolismo , Pene/patología , Distribución TisularRESUMEN
Neuroadaptations among glutamatergic projections within the mesocorticolimbic circuits engaged by drugs of abuse have been described since the 1990s. There is now substantial evidence that drugs of abuse lead to long-term changes in glutamatergic signaling and encompass multiple levels of analysis. For example, cocaine induces changes in extracellular glutamate concentrations and in synaptic glutamatergic transmission. In addition, glutamate receptors are required for the expression of cocaine-related behaviors, and long-term changes have been reported in the expression of proteins at glutamatergic synapses, in glutamate-related redox regulation of neurons, and in glutamatergic synaptic and structural plasticity following chronic exposure to cocaine. In this chapter, we will describe the neurocircuitry involved, and will summarize evidence for adaptations in glutamatergic neuroplasticity as a mechanism for cocaine addiction. Finally, we will discuss progress in the development of glutamate-mediated pharmacotherapies for the treatment of cocaine dependence.
Asunto(s)
Trastornos Relacionados con Cocaína/fisiopatología , Ácido Glutámico/metabolismo , Plasticidad Neuronal , Animales , Trastornos Relacionados con Cocaína/tratamiento farmacológico , Trastornos Relacionados con Cocaína/metabolismo , Homeostasis , Humanos , Red Nerviosa/fisiopatología , Oxidación-ReducciónRESUMEN
Oxidative and nitrosative stress result in the accumulation of reactive oxygen and nitrogen species (ROS/RNS) which trigger redox-mediated signaling cascades through posttranslational modifications on cysteine residues, including S-nitrosylation (P-SNO) and S-glutathionylation (P-SSG). Protein disulfide isomerase (PDI) is the most abundant chaperone in the endoplasmic reticulum and facilitates protein folding via oxidoreductase activity. Prolonged or acute nitrosative stress blunts the activity of PDI through the formation of PDI-SNO and PDI-SSG. The functional implication is that reduced activity for the period of time leads to an accumulation of misfolded or unfolded proteins and activation of the unfolded protein response. Redox regulation of PDI and downstream signaling events provides an integration point for the functional determination of cell survival pathways. Herein, we describe the methodologies to globally identify S-glutathionylated targets of ROS/RNS; validate and identify the specific cysteine targets and characterize the structural and functional consequences.
Asunto(s)
Glutatión/metabolismo , Proteína Disulfuro Isomerasas/metabolismo , Especies de Nitrógeno Reactivo/metabolismo , Estrés Fisiológico , Células Cultivadas , Cisteína/metabolismo , Electroforesis en Gel Bidimensional/métodos , Humanos , Oxidación-Reducción , Estrés Oxidativo , Proteína Disulfuro Isomerasas/química , Proteínas/química , Proteínas/metabolismo , Transducción de Señal/fisiología , Espectrometría de Masa por Láser de Matriz Asistida de Ionización Desorción/métodosRESUMEN
Redox homeostasis governs a number of critical cellular processes. In turn, imbalances in pathways that control oxidative and reductive conditions have been linked to a number of human disease pathologies, particularly those associated with aging. Reduced glutathione is the most prevalent biological thiol and plays a crucial role in maintaining a reduced intracellular environment. Exposure to reactive oxygen or nitrogen species is causatively linked to the disease pathologies associated with redox imbalance. In particular, reactive oxygen species can differentially oxidize certain cysteine residues in target proteins and the reversible process of S-glutathionylation may mitigate or mediate the damage. This post-translational modification adds a tripeptide and a net negative charge that can lead to distinct structural and functional changes in the target protein. Because it is reversible, S-glutathionylation has the potential to act as a biological switch and to be integral in a number of critical oxidative signaling events. The present review provides a comprehensive account of how the S-glutathionylation cycle influences protein structure/function and cellular regulatory events, and how these may impact on human diseases. By understanding the components of this cycle, there should be opportunities to intervene in stress- and aging-related pathologies, perhaps through prevention and diagnostic and therapeutic platforms.
Asunto(s)
Glutatión/metabolismo , Animales , Humanos , Enfermedades del Sistema Nervioso/metabolismo , Procesamiento Proteico-Postraduccional , Especies Reactivas de Oxígeno/metabolismo , Transducción de SeñalRESUMEN
Impaired glutamate homeostasis in the nucleus accumbens has been linked to cocaine relapse in animal models, and results in part from cocaine-induced downregulation of the cystine-glutamate exchanger. In addition to regulating extracellular glutamate, the uptake of cystine by the exchanger is a rate-limiting step in the synthesis of glutathione (GSH). GSH is critical for balancing cellular redox in response to oxidative stress. Cocaine administration induces oxidative stress, and we first determined if downregulated cystine-glutamate exchange alters redox homeostasis in rats withdrawn from daily cocaine injections and then challenged with acute cocaine. Among the daily cocaine-induced changes in redox homeostasis were an increase in protein S-glutathionylation and a decrease in expression of GSH-S-transferase pi (GSTpi). To mimic reduced GSTpi, a genetic mouse model of GSTpi deletion or pharmacological inhibition of GSTpi by administering ketoprofen during daily cocaine administration was used. The capacity of cocaine to induce conditioned place preference or locomotor sensitization was augmented, indicating that reducing GSTpi may contribute to cocaine-induced behavioral neuroplasticity. Conversely, an acute cocaine challenge after withdrawal from daily cocaine elicited a marked increase in accumbens GSTpi, and the expression of behavioral sensitization to a cocaine challenge injection was inhibited by ketoprofen pretreatment; supporting a protective effect by the acute cocaine-induced rise in GSTpi. Together, these data indicate that cocaine-induced oxidative stress induces changes in GSTpi that contribute to cocaine-induced behavioral plasticity.
Asunto(s)
Cocaína/administración & dosificación , Actividad Motora/fisiología , Plasticidad Neuronal/fisiología , Estrés Oxidativo/fisiología , Adaptación Fisiológica/efectos de los fármacos , Adaptación Fisiológica/fisiología , Animales , Gutatión-S-Transferasa pi/metabolismo , Masculino , Ratones , Ratones Noqueados , Actividad Motora/efectos de los fármacos , Plasticidad Neuronal/efectos de los fármacos , Oxidación-Reducción/efectos de los fármacos , Estrés Oxidativo/efectos de los fármacos , RatasRESUMEN
Proteins in the nucleus accumbens mediate many cocaine-induced behaviors. In an effort to measure changes in nucleus accumbens protein expression as potential biomarkers for addiction, coronal tissue sections were obtained from rats that developed behavioral sensitization after daily administration of cocaine, or from daily saline-treated controls. The tissue sections were subjected to matrix-assisted laser desorption/ionization (MALDI) mass spectrometry (MS) profiling and tissue imaging. For profiling experiments, brain sections were manually spotted with matrix over the nucleus accumbens, a brain region known to regulate cocaine sensitization. Summed mass spectra (10,000 laser shots, grid) were acquired and spectra were aligned to reference peaks. Using bioinformatics tools, eight spectral features were found to be altered by cocaine treatment. Based on additional sequencing experiments with MALDI tandem MS and database searches of measured masses, secretoneurin (m/z 3653) was identified as having an increased expression. In addition, the distribution of m/z 3653 in the nucleus accumbens was determined by MALDI tissue imaging, and the increased expression of its precursor protein, secretogranin II, was verified by immunoblotting.