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The role of chemokines as chemotactic cytokines and their functions in the immune system and related pathologies are well defined. Recently, strong evidence supporting the hypothesis that chemokines can act as modulators of neuronal activity and influence neurotransmission has been reported. The chemokine CXCL12 is constitutively expressed in adult brain and expression of CXCL12 and its cognate receptor CXCR4 have been reported in regions of rat brain that construct dopamine (DA) and glutamate (GLU) pathways such as ventral tegmental area (VTA), substantia nigra (SN), and nucleus accumbens (NAc). In the central nervous system (CNS), activation of CXCR4 on dopaminergic neurons and astrocytes initiate cascade of events that leads to DA and GLU release and influence synaptic transmission. In vivo, intracerebroventricular (ICV) CXCL12 has been shown to potentiate cocaine-induced locomotor activity. Based on these evidences, the studies, as outlined in this dissertation, aimed to expand understanding of how CXCL12/CXCR4 interaction can affect cocaine-induced behavior and reinforcement, with special focus on mechanisms involving GLU. We first evaluated involvement of CXCR4 activation by CXCL12 on cocaine-induced locomotor activity using a selective CXCR4 antagonist AMD3100. Results demonstrated that AMD3100 (5, 10 mg/kg, IP) pretreatment dose-dependently attenuated cocaine-induced locomotor activity without affecting the baseline activity. Thereafter, effects of AMD3100 on cocaine’s reinforcing efficacy were tested using a biased conditioned place preference (CPP) paradigm. In all CPP experiments, saline pretreated controls established a significant preference for the cocaine-paired context following four pairings with cocaine (10 mg/kg, IP). Rats pretreated with 2.5 and 5 mg/kg AMD3100 prior to each pairing session showed significantly lower preference for the cocaine-paired side, whereas rats pretreated with 1 mg/kg AMD3100 showed similar preference for the cocaine-paired side as the saline controls when tested in the absence of the drug. Rats pretreated with AMD3100 (5 mg/kg, IP) just once prior to testing showed significantly lower preference for the cocaine-paired side. These results demonstrate that CXCR4 antagonism reduces development and expression of cocaine-induced CPP. Intravenous cocaine self-administration (SA) was performed to examine the effects of AMD3100 on the acquisition of cocaine-taking behavior and reinstatement to cocaine-seeking. Acquisition of cocaine SA was studied using three doses of cocaine (0.375, 0.5, 0.75 mg/kg/infusion) on a fixed-ratio 1 (FR-1) schedule of reinforcement. Two doses of AMD3100 (5, 10 mg/kg, IP) were tested. In all SA experiments, saline pretreated controls readily acquired cocaine self-administration. The lower and higher AMD3100 decreased the number of reinforcers earned during the two hour sessions compared to saline controls when tested against acquisition of 0.375 and 0.5 mg/kg/infusion cocaine. However, when tested against the 0.75 mg/kg/infusion cocaine, only 10 mg/kg of AMD3100 resulted in reduction in responding, but not the lower dose. When a dose response curve was plotted using all doses of cocaine and AMD3100 tested, the effects of AMD3100 were represented by a significant downward shift of the dose response curve. Effects of AMD3100 on cocaine-seeking were evaluated using the reinstatement model, in which rats that were extinguished from self-administration of 0.5 mg/kg/infusion cocaine underwent reinstatement testing with cue or cue + drug presentation. A compound cue (light and tone stimulus), that was used during the acquisition training, and submaximal dose of cocaine (5mg/kg, IP) were used. In both reinstatement conditions, rats pretreated with saline reinstated following the presentation of cue or cue + drug prime. Rats pretreated with AMD3100, 30 minutes prior to reinstatement session, showed significantly lower number of lever presses indicating drug-seeking was not as robust compared to the saline pretreated controls. Following the observations that cocaine-induced behaviors may be partially mediated by CXCL12/CXCR4 interaction, neurochemical changes were examined to elucidate the underlying mechanisms. CXCR4 immunoreactivity in prefrontal cortex (PFC) following withdrawal from 7 days of repeated cocaine (15 mg/kg, IP) was evaluated. Although positive CXCR4 immunoreactivity was observed in PFC, there were no significant differences in the intensity of CXCR4 expression compared to the saline treated controls at acute (2 hours, 2 and 10 days) or protracted (30 days) withdrawal time points. In contrast, CXCL12 protein levels in PFC and NAc were negatively influenced after protracted withdrawal from 7 days of repeated cocaine (15 mg/kg, IP) administration. Following assessment of regional expression of CXCR4, cellular expression was evaluated using triple labeling immunohistochemistry which revealed the positive CXCR4-immunoreactivity on cells staining positively for vesicular glutamate transporter 1 (vGlut1) and glial fibrillary acidic protein (GFAP) showing that the glutamatergic neurons and astrocytes in the PFC express CXCR4. To assess the effects of CXCL12 on GLU transmission, microdialysis of NAc was performed. Following unilateral injection of 50 ng CXCL12 into the lateral ventricle, increase in extracellular GLU was observed. In a follow up study, AMD3100 pretreatment (10 mg/kg, IP) attenuated cocaine-induced increase in extracellular GLU in the NAc. Since the glutamate transporter subtype-1 (GLT-1) is a major regulator of extracellular GLU and upregulation of GLT-1 expression and function has been shown to attenuate reinstatement to cocaine-seeking, its expression was evaluated using immunoblot analysis of the NAc and PFC of rats that self-administered cocaine. The results revealed that AMD3100 (10 mg/k, IP; daily injection 30 min prior to SA session) pretreatment upregulated GLT-1 levels in the NAc but not PFC. In summary, results of the present study show that CXCL12/CXCR4 interaction may modulate cocaine-induced behavioral effects including reinforcement and reinstatement to cocaine-seeking. Neurochemical assessments revealed the presence of CXCR4-expressing glutamatergic neurons in the PFC and AMD3100-induced up-regulation of GLT-1. Most importantly, we provided direct evidence of CXCL12/CXCR4 mediated GLU transmission in NAc. Together, these results expand our understanding of chemokine’s role as neuromodulators and identify CXCR4 as a novel target for development of new pharmacotherapies for the treatment of cocaine addiction. / Pharmacology

ABSTRACT: UTILIZING NOVEL DOSE EQUIVALENCE METHODOLOGIES TO EXAMINE COCAINE'S EFFECTS ON THE VASCULATURE Neil S. Lamarre Doctor of Philosophy Temple University School of Medicine, 2013 Doctoral Advisory Committee Chair: Ronald J. Tallarida, Ph.D. Cocaine abuse and addiction is a serious health problem, resulting in thousands of emergency room visits and deaths each year in the United States. It is particularly toxic to the cardiovascular system, including deleterious effects on the peripheral vasculature. These effects are not well understood, but evidence suggests chronic cocaine use may lead to endothelial dysfunction, thereby increasing relative risk of a number of other cardiovascular diseases including stroke, aneurysm, myocardial infarction, hypertension, etc. Data from our lab, and others, suggest that the presence of a functional endothelium has a dramatic effect on the contractility of the rat aorta that is agonist-specific. Attenuation of this endothelium-dependent vasodilatory component of agonist action is a primary feature of endothelial dysfunction. We have utilized dose equivalence theory to calculate the dose response relationship for the endothelium-dependent vasodilatory component of an agonist causing overt vasoconstriction. This component cannot be measured directly, but our novel methodology allows us to quantitate agonist-specific impairment of vasodilation, and describe it using the familiar parameters of the dose response curve. Another strength of this method, relative to currently used in vitro methods, is that it also avoids the confounding variable of a second agonist used to produce the initial vasoconstriction. To validate the methodology, a pilot study was performed examining the endothelial dysfunction in STZ-induced diabetic rats, as a positive control for endothelial dysfunction. Interestingly, this treatment showed impairment in the endothelium-dependent vasodilatory component of action of norepinephrine, but not of angiotensin-II. Thus, our initial hypothesis was confirmed - that disruption of the vasodilatory components of various agonists are independent, and that agonist-specific information may prove useful. Next, we employed our new methodology utilizing the rat aorta as our vascular model to test the hypothesis that chronic cocaine administration causes endothelial dysfunction. We first examined the endothelium-dependent vasodilation component of a number of physiologically important vasoconstrictors, and attempted to determine which vasodilatory mediators contributed to the effect. We found the endothelium to have a profound effect on the dose response curve to three important endogenous agonists. These data suggest that under conditions of endothelial dysfunction exaggerated vasoconstriction could occur, even within normal plasma concentration ranges of these vasoconstrictors, resulting in elevated blood pressure and further damage to the endothelium over time. No endothelial dysfunction was observed with this treatment paradigm, using our methodology or the standard approach. This may be a result of insufficient duration of cocaine treatment, or a result of our selection of the rat aorta as a model. We wanted to further investigate which vasodilatory mechanisms were involved in this vasodilatory component of action. We inhibiting various endothelium-derived mediators of this vasodilatory component of action (such as nitric oxide or prostacyclin), which revealed differential activation of these mediators by the agonists examined. For example, inhibition of nitric oxide synthesis abolished the endothelium-dependent vasodilatory component of endothelin-1, but only partially attenuated that of angiotensin-II. Thus, the agonist-specific pattern of impairment may also prove useful in examining the underlying mechanisms of impaired vasodilation. Endothelial dysfunction is one reported consequence of long term cocaine abuse; however, there are conflicting reports on the acute vascular effects of cocaine, with some reports concluding that cocaine is a vasoconstrictor, and some reporting its action as a vasodilator. There are in vitro reports of cocaine causing release of vasoconstrictors from the endothelium, which supports the longstanding notion of cocaine as a vasoconstrictor. However, one recent report demonstrates a dose-dependent vasodilatory effect of cocaine in rat aorta that is independent of the endothelium. This complexity is perhaps due, in part, to cocaine's affinity for a number of molecular targets, acting in combination. In examining the acute action of cocaine in our preparation, we observed an "inverted-U" shaped dose response, also referred to as a hormetic dose response curve. We then applied dose equivalence methodology in order to derive the "unknown" second component contributing the vasodilatory action of cocaine at higher doses. This methodology lets us calculate this unknown component, and describe it with the familiar parameters of a dose response curve, which could potentially aid in the identification of the unknown component. The preliminary studies with acute cocaine utilized a sub-maximal dose of phenylephrine in order to observe tension changes in either direction. This prompted us to further characterize the interaction of cocaine with other alpha adrenoceptor agonists. Importantly, because cocaine alone had no effect at doses up to 100 µM, but potentiated the vasoconstriction of alpha agonists, the interaction is therefore synergistic. This constitutes evidence of a previously undescribed mechanism contributing to cocaine's vasoconstricting effect. In vivo, reuptake inhibition is a major mechanism for cocaine-induced vasoconstriction, but is excluded in this experiment by virtue of low levels of sympathetic innervation in the rat aorta, and the use of methoxamine, an alpha agonist not subject to the reuptake mechanisms. This interaction may contribute to cocaine-induced vasoconstriction in the coronary arteries, especially in circumstances of endothelial dysfunction. In summary, the work presented in this dissertation applies new methodologies utilizing dose equivalence theory to the study of cocaine's effects on peripheral vasculature, and presents novel findings of synergy with respect to cocaine's enhancement on the action of alpha adrenoceptor-mediated vasoconstriction. / Pharmacology

Cocaine use has contributed to 5 million individuals falling into the cycle of addiction. Prior research in cocaine dependence mainly focused on rewards. Losses also play a critical role in cocaine dependence as dependent individuals fail to avoid social, health, and economic losses even when they acknowledge them. However, dependent individuals are extremely adept at escaping negative states like withdrawal. To further understand whether cocaine use may contribute to dysfunctions in aversive learning, this paper uses fMRI and an aversive learning task to examine cocaine dependent individuals abstinent from cocaine use (C-) and using as usual (C+). Specifically of interest is the neural signal representing actual loss compared to the expected loss, better known as prediction error (δ), which individuals use to update future expectations. When abstinent (C-), dependent individuals exhibited higher positive prediction error (δ+) signal in their striatum than when they were using as usual. Furthermore, their striatal δ+ signal enhancements from drug abstinence were predicted by higher positive learning rate (α+) enhancements. However, no relationships were found between drug abstinence enhancements to negative learning rates (α±-) and negative prediction error (δ-) striatal signals. Abstinent (C-) individuals' striatal δ+ signal was predicted by longer drug use history, signifying possible relief learning adaptations with time. Lastly, craving measures, especially the desire to use cocaine and positive effects of cocaine, also positively correlated with C- individuals' striatal δ+ signal. This suggests possible relief learning adaptations in response to higher craving and withdrawal symptoms. Taken together, enhanced striatal δ+ signal when abstinent and adaptations in relief learning provide evidence in supporting dependent individuals' lack of aversive learning ability while using as usual and enhanced relief learning ability for the purpose of avoiding negative situations such as withdrawal, suggesting a neurocomputational mechanism that pushes the dependent individual to maintains dependence. / Master of Science

La dopamine (DA) contrôle l'apprentissage lié à la récompense en régulant l'activité et la plasticité de la transmission corticostrialale. Les effets à long terme de la DA impliquent des changements dans la transcription des gènes. Le but de ce travail de thèse est d'étudier les changements transcriptionnels produit dans le striatum ventral, dorsal et cortex préfrontal, par un protocole d'apprentissage opérant ou après une activation du système de la récompense par des injections de cocaïne. Les neurones épineux moyens du striatum peuvent être séparé en deux populations fonctionnelles sur la base de l'expression du récepteur de type 1 de la DA (D1R) ou de type 2 (D2R). Des souris transgéniques expriment une protéine ribosomale étiqueté avec la GFP sous le contrôle du promoteur de D1R ou D2R ont été utilisés afin d'isoler les ARN messagers (ARNm) des neurones D1 ou D2. La première partie de ce travail est centré sur la comparaison de l'expression des gènes dans les différentes populations neuronales exprimant le D1R ou D2R appartenant aux différentes régions d'intérêt, ce qui apporte une caractérisation précise nouvelle des neurones cibles de la DA. Dans un deuxième temps, nous avons caractérisé les modifications produites dans chaque population neuronale par une stimulation passive du système de récompense (traitement chronique à la cocaïne) ou un recrutement actif (apprentissage opérant pour la nourriture). / Dopamine (DA) controls movement execution, action selection, and incentive learning by regulating the activity and plasticity of corticostriatal transmission. Long-term modifications require changes in gene transcription. The aim of this work is to study the changes in transcriptions following an operant learning protocol or mimicking stimulation of the reward system with cocaine in the dorsal striatum and the nucleus accumbens in the striatum, and in the prefrontal cortex. The medium-size spiny striatal projection neurons (SPNs) can be divided into 2 different populations based on the expression of the D1 or D2 DA receptor that participate in distinct pathways, which have opposite functional effects on their target regions. We used transgenic mice that express a tagged ribosomal protein (L10a-EGFP) under control of the D1 or D2 receptor promoter to isolate currently translated mRNA and nuclei from each population of SPNs, as well as from D1 neurons of the prefrontal cortex following passive stimulation of the reward system (chronic treatment with cocaine) and active recruitment of the reward system (operant learning for food). Firstly we compared the basal gene expression in the different neuronal populations characterized by the expression of D1 or D2 receptors and their regional localization. We identified hundreds of differentially expressed mRNA providing a precise characterization of the cellular and regional differences. In the second part, we characterized the changes induced in each neuronal population by a 1-week exposure to cocaine or after operant training for food.

Cocaine is a widely abused and addictive drug, resulting in serious medical and social problems in modern society. Currently, there is no FDA-approved medication specific for cocaine abuse treatment. The disastrous medical and social consequences of cocaine abuse have made the development of an anti-cocaine medication a high priority. However, despite decades of efforts, traditional pharmacodynamic approach has failed to yield a truly useful small-molecule drug due to the difficulties inherent in blocking a blocker like cocaine without affecting the normal functions of the transporters or receptors. An alternative approach, i.e. pharmacokinetic approach, is to interfere with the delivery of cocaine to its receptors/transporters and/or accelerate its metabolism in the body. It would be an ideal anti-cocaine medication to accelerate cocaine metabolism producing biologically inactive metabolites. Two natural enzymes may catalyze hydrolysis of cocaine: human butyrylcholinesterase (BChE) and bacterial cocaine esterase (CocE). However, the wild-type enzymes are not suitable as anti-cocaine therapeutics, due to the low catalytic activity, thermoinstability, or short biological half-life. In this investigation, we performed integrated computational-experimental studies to rationally design and discover mutants of these enzymes in order to improve the catalytic activity, thermostability, and/or biological half-life. To rationally design desirable mutants of the enzymes, we have successfully developed computational models, including those for BChE gating, glycosylated BChE structure, BChE-substrate complex structures, BChE dimer/tetramer structures, CocE monomer/dimer structures, and CocE-substrate complex structures. Development of the computational models enabled us to rationally design new amino-acid mutations that may improve the catalytic activity, thermostability, and/or prolonged biological half-life. The computational design was followed by wet experimental tests, including both in vitro and in vivo experiments, leading to discovery of new enzyme forms with not only a high catalytic efficiency against cocaine, but also an improved thermostability and/or prolonged biological half-life. The identified new mutants of BChE and CocE are expected to be valuable candidates for development of a more efficient enzyme therapy for cocaine abuse. The encouraging outcomes of the present study also suggest that the structure-and-mechanism-based design and integrated computational-experimental approach is promising for rational drug design and discovery.

abstract: Cocaine abuse affects millions of people with disastrous medical and societal consequences. Despite this, there is still no FDA-approved treatment to decrease the likelihood of relapse in rehabilitated addicts, and acute cocaine toxicity (overdose) is only symptomatically treated. Studies have demonstrated a promising potential treatment option with the help of the human serum enzyme butyrylcholinesterase (BChE), an enzyme capable of breaking down cocaine into biologically inactive side products. This activity of wild-type BChE, however, is relatively low. This prompted the design of variants of BChE which exhibit significantly improved catalytic activity against cocaine. Plants were used as a sustainable, scalable, affordable platform system to produce large amounts of human biologics such as these cocaine hydrolase variants of BChE. Using a tobacco relative, Nicotiana benthamiana, recombinant enzymes can be produced at quantities relevant to clinical use with desired kinetic properties. Next, the ability of the most promising plant-produced cocaine super hydrolase, pCocSH, to counter the lethal effects of cocaine overdose in vivo was tested. These studies revealed that this plant-produced enzyme can protect mice from an otherwise lethal dose of cocaine. Most excitingly, it was found that pCocSH can rescue mice from overdose when given immediately after the onset of cocaine-induced seizures. These studies provide in vitro and in vivo proof-of-principle for a promising plant-derived biologic to be used as a pharmacokinetic-based treatment for cocaine addiction-related diseases such as overdose. / Dissertation/Thesis / Doctoral Dissertation Molecular and Cellular Biology 2015

Orientador: Renata Cruz Soares de Azevedo / Tese (doutorado) - Universidade Estadual de Campinas, Faculdade de Ciências Médicas / Made available in DSpace on 2018-08-27T12:58:53Z (GMT). No. of bitstreams: 1 Oliveira_KarinaDiniz_D.pdf: 1545858 bytes, checksum: fc5c6d38466b6c63873474240fcefa4d (MD5) Previous issue date: 2015 / Resumo: Objetivos: descrever o perfil sociodemográfico e o padrão de uso de substâncias psicoativas (SPA) em pacientes admitidos em unidade de emergência (UE) por traumas. Além disso, relacionar a detecção laboratorial de SPA com a gravidade e o mecanismo de trauma. Métodos: Estudo quantitativo, de corte transversal e longitudinal realizado com sujeitos maiores de 18 anos, admitidos em UE em decorrência de traumas. Os instrumentos utilizados foram: questionário com dados sociodemográficos e de padrão de consumo de SPA, e as seções J e K do "Mini International Neuropsychiatric Interview", para avaliação de abuso e dependência. Os pacientes que apresentaram uso nocivo ou dependência de SPA foram submetidos à intervenção breve. Foram coletadas amostras de sangue e urina para pesquisa laboratorial de álcool, cocaína, crack, cocaetileno e canabinóides. Dos prontuários médicos, foram levantados os dados de mecanismo e gravidade do trauma (avaliado pelos escores RTS ¿ Revised Trauma Score ¿ e ISS ¿ Injury Severity Score). O seguimento foi realizado através de contato telefônico um ano após o evento trauma para avaliação do padrão de uso de SPA. Resultados: Foram incluídos no estudo 453 indivíduos, em sua maioria homens, com média de idade 36,1 anos, 8 anos de escolaridade, com filhos e laboralmente ativos. 348 pacientes responderam ao questionário. Padrão de poliuso e dependência foram detectados em 147 e 37 sujeitos respectivamente, principalmente em homens jovens. Houve predomínio de acidentes de trânsito e maior proporção de homens nos mecanismos ferimentos com arma branca, acidentes de moto e ferimentos por projétil de arma de fogo. Das 435 amostras de sangue e urina coletadas, 169 foram positivas para a presença de SPA: álcool (21,2%), cocaína (19,8%), canabinóides (13%), crack (11%), cocaetileno (15,9%). Houve diferença significativa na comparação da análise laboratorial de SPA com o mecanismo de trauma, com correlação negativa para cocaína/crack no acidente de trânsito e correlação positiva para todas as SPA no trauma de violência. Os pacientes com análises positivas para álcool, cocaína, crack e cocaetileno apresentaram traumas mais graves (RTS<7,84). Quando considerado o ISS, os traumas mais graves foram apresentados por sujeitos cujas amostras foram positivas para cocaetileno e crack (ISS>16). A maior letalidade foi causada por atropelamentos, responsável por 13/41 (31,7%) dos óbitos. Intervenção breve não interferiu na mudança de padrão de uso de SPA relatado no seguimento de um ano. Conclusões: Homens, jovens, com 4 a 8 anos de escolaridade, sem companheira fixa, com filhos e laboralmente ativos foram a maioria dos sujeitos do estudo. O padrão de consumo de SPA nas vítimas de trauma mostrou início de uso antes dos 18 anos de idade e grande proporção de abuso e dependência. A presença de álcool e drogas ilícitas na análise laboratorial em vítimas de trauma foi elevada, com destaque para cocaína e crack. O mecanismo de trauma mais comum foi acidente de trânsito, com maior letalidade no atropelamento. A presença de álcool, crack e cocaetileno esteve associada a maior gravidade do trauma. Em relação a outros mecanismos, trauma de violência esteve associado a maior detecção positiva de SPA / Abstract: Objectives: describing sociodemographic profile and pattern of psychoactives substances (PSA) use in patients treated for injuries in an Emergency Unit. Furthermore, unite the PSA laboratorial detection with the severity and injury mechanism. Methods: quantitative study, transversal and longitudinal, with subjects older than 18, admitted in ER for trauma. The instruments applied were a sociodemographic questionnaire and the J and K sections of Mini International Neuropsychiatric Interview (M.I.N.I.) to evaluate PSA abuse and dependence. Blood and urine samples were collected to detect alcohol, cocaine, crack, cocaethylene and THC. Data from injury mechanism and lesions severity (evaluated through RTS ¿ Revised Trauma Score ¿ and ISS ¿ Injury Severity Score) were found in medical records. The following were made by phone contact to evaluate pattern of PSA use one year after trauma. Results: 453 subjects, male, average age 36,3 years, 8 years of scholarity, with kids and working. 348 answered the questionnaire. Polyuse and poly-dependance pattern were detected in 147 and 37 patients respectively, mainly young men. The predominant trauma mechanism was traffic-related injuries. In young men the main mechanisms were motocycle accidents, cold steal and firearm perforation. From 435 urine and blood samples collected, 169 (38,8%) detected some PSA: alcohol (21,2%), cocaine (19,8%), THC (13%), crack (11%), cocaethylene (15,9%). There was a significant correlation between the sample analysis and the trauma mechanism. Negative correlation for crack and cocaine in traffic related injuries and positive correlation for all PSA in violence-related injuries. Subjects whose samples were positive to alcohol, cocaine, crack and cocaethylene showed more severe traumas according to RTS. When ISS is considered, more severity in the patients whose samples were positive to crack and cocaethylene (ISS>16). Major lethality caused by tramplings (31,7% of the 41 deaths). Brief intervention didn't change the pattern of PSA use one year after trauma. Conclusions: Most subjects were men, young, 4 to 8 years of scholarity, without partner, with kids and working. Trauma patients began the use of PSA during the youth and showed great percentages of abuse and dependence. Positive samples percentages were high, specially crack and cocaine. Predominant trauma mechanism was traffic accident, and trampling was the most lethal mechanism. Positive samples for alcohol, crack and cocaethylene were associated to major severity of trauma. Violence-related traumas were associated to positive samples more than other mechanisms / Doutorado / Saude Mental / Doutora em Ciências Médicas

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