2006 — 2010 |
Choi, Doo-Sup |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Creb, Alcohol Reward and Consumption in Ent1 Null Mice
[unreadable] DESCRIPTION (provided by applicant): Ethanol inhibits the type 1 equilibrative nucleoside transporter (ENT1) in cultured cells. Preliminary studies with ENT1 null mice indicate that ENT1 is also a target for ethanol in vivo since ENT1 null mice are less responsive to acute effects of ethanol. ENT1 null mice also consume more ethanol than wild type littermates. Preliminary studies demonstrate that glutamate-driven CREB activation was increased in the striatum of ENT1 null mice. This appears to result from diminished activation of striatal presynaptic adenosine A1 receptors due to reduced adenosine tone as measured by electrophysiological studies. Since striatal CREB activation is associated with reduced drug reward, excessive ethanol drinking in ENT1 null mice may be causally related to tolerance to ethanol reward. Consistent with this hypothesis, a conditioned place preference study demonstrated that ENT1 null mice prefer the ethanol-paired side (2.0 g/kg) significantly less than wild type mice. This proposal will expand upon preliminary studies and examine the role of CREB signaling in regulating behavioral responses to alcohol in ENT1 null mice. First, initial sensitivity, acute and chronic tolerance, operant self-administration, and place conditioning assays will be used to examine ethanol tolerance, and rewarding and reinforcing effects of ethanol. Second, increases in CREB activity will be identified in specific cells using CRE-lacZ reporter mice and by examining expression of two CRE-driven genes, enkephalin and dynorphin, in the striatum of ENT1 null mice. Third, pCREB immunoreactivity will be used to measure CREB activity in striatal brain slices to identify signaling pathways that contribute to increased basal CREB activity in ENT1 null mice. Finally, we will determine whether alterations in signaling pathways that account for increased striatal pCREB contribute to tolerance to rewarding effects of ethanol and increased ethanol consumption in ENT1 null mice. The goal of this project is to understand signaling pathways underlying enhanced alcohol drinking behavior in ENT1 null mice and to identify novel therapeutic targets for alcoholism. [unreadable] [unreadable]
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1 |
2009 — 2019 |
Choi, Doo-Sup |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Alcohol and Adenosine-Mediated Glutamate Signaling in Neuro-Glial Interaction
DESCRIPTION (provided by applicant): Studies with ENT1 null mice indicate that ENT1 regulates ethanol intoxication and preference, as well as motivational effects of ethanol. These behaviors appear to be attributed to the increased glutamate signaling in the striatum where cortical glutamatergic axons mainly send their signaling to control motor functions, habits and motivations. We found that EAAT2 expression was reduced in ENT1 null mice by proteomics, and confirmed it by Western blot analysis, indicating that the increased glutamate levels in ENT1 null mice may be partly due to the reduced synaptic glutamate uptake by EAAT2 in astrocytes. Despite evidence demonstrating that a genetic variant of EAAT2 (G603A) is implicated in alcoholism, regulation of astrocytic EATT2 expression and function in response to ethanol is poorly understood in molecular, cellular and behavioral levels. Considering that ENT1 and EAAT2 are predominantly expressed in the astrocytes, our main hypothesis is that inhibition of ENT1 causally reduces EAAT2 expression through intracellular mechanisms in the astrocytes. This hypothesis will be tested using cultured astrocytes, ENT1 null mice, and a novel bi-transgenic mouse line that expresses green fluorescent protein in astrocytes in ENT1 null background. First, we will determine if ethanol alters ENT1 and EAAT2 expression and function in the astrocytes. We will also investigate astrocyte-specific signaling pathways involved in ENT1 and EAAT2 expression and function using a proteomic technique. Using tandem mass spectrometry and a newly developed electrophysiological method, we will determine if ethanol alters adenosine and glutamate releases from the astrocytes. Secondly, to investigate the physiological role of ENT1 and EAAT2 in the astrocytes, we will examine astrocytes function in ENT1 null mice using bi-transgenic mice, GFAP-EGFP/ENT1 null mice, or GFAP-EGFP/ENT1 wild-type mice. We will isolate the astrocytes using FACS (fluorescent-assisted cell sorting), and then will examine protein profiles using a mass-tag labeling proteomic technique, iTRAQ, to compare between genotypes with saline or different ethanol doses. Following this, we will validate the altered protein expressions using a functional proteomics such as Western blot and immunofluorescence experiments. Finally, we will determine whether pharmacological or genetic regulations of EAAT2 alter alcohol preference and reward in mice. The overall goal of this project is to identify a novel ENT1 and EAAT2 signaling pathway that regulates ethanol responses in the astrocytes and neuro-glial interactions which may contain targets for the development of new therapeutics to treat alcohol use disorders in humans. PUBLIC HEALTH RELEVANCE: We will investigate the role of ethanol-sensitive adenosine transporter, ENT1 and a glutamate transporter, EAAT2, in the striatal astrocytes. We will use cultured astrocytes, ENT1 null mice, and astrocyte-specific marker expressing mice to carry out cellular, molecular, biochemical, pharmacological, and behavioral studies. The results of our studies are expected to define a novel ENT1 and EAAT2 signaling pathway that regulates ethanol response in the astrocytes and neuro-glial interactions, which may lead us to develop new therapeutics to treat alcohol use disorders.
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0.954 |
2010 |
Choi, Doo-Sup |
P20Activity Code Description: To support planning for new programs, expansion or modification of existing resources, and feasibility studies to explore various approaches to the development of interdisciplinary programs that offer potential solutions to problems of special significance to the mission of the NIH. These exploratory studies may lead to specialized or comprehensive centers. |
The Mayo Clinic Center For Individualized Treatment of Alcohol Dependence
DESCRIPTION (provided by applicant): The Mayo Clinic Center for the Individual Treatment of Alcohol Dependence (CITA) is a P20 exploratory/ developmental alcohol research center proposal with the over-arching theme of using translational research strategies to create a new research center with the capacity to originate and conduct pharmacogenomic probe studies to differentiate treatment responses in patients with severe alcohol dependence. This new center would build upon an already existing team of researchers conducting synergistic clinical and preclinical translational research in a major academic medical center with resources already devoted to translation research and training in the provision of individualized clinical care. The importance of the goal of being able to provide individualized medical treatment for alcohol dependence has become increasingly apparent. This is specifically true related to the identification of variable responses to antidipsotropic medications. Whereas some individuals have excellent responses, there are clearly many who do not. The ability to be able to reliably differentiate those who will respond to an effective treatment has multiple benefits. The efficient identification of treatment responders would result in enormous saving of both cost and personal suffering. Another potential benefit would be the development of new medications with very targeted indications that would be uniquely helpful for selected individuals who could be identified by low cost genotyping. The feasibility of establishing this innovative approach to the study of alcohol treatment is dependent on close collaboration between the investigators of the P20 Center and the scientists who are currently working as part of the Pharmacogenomic Research Network team (PGRN) and the Advanced Genomic Technology Center (AGTC). Additionally, the broad resources of the Center for Translational Science Activities (CTSA) at the Mayo Clinic will provide a strong foundation from which to build translational research studies utilizing state-of-the-art genotyping technology. Four exploratory projects are described that foster translation from preclinical to clinical investigations. Two projects explore the relationship between genetic variation and response to acamprosate administration. The first uses a mouse model while the second is a pharmacogenomic probe study using a prospectively defined sample of subjects with alcohol dependence. The remaining two projects use magnetic resonance spectroscopy to explore the relationship between glutamate concentrations in the central nervous system and acamprosate treatment in mice and in patients treated for alcohol dependence.
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0.954 |
2021 |
Choi, Doo-Sup |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Astrocyte-Neuron Interaction in the Dorsal Striatum and Ethanol-Seeking Behaviors
Project Summary The main goal of our proposal is to investigate the role of astrocytes in the dorsal striatum (DS), which regulates goal-directed and habitual reward-seeking behaviors in mice. The DS has a critical role in shaping goal-directed and habitual actions, which are the main determinants for the reward-dependent decision-making process. Astrocytic processes in close proximity to the synaptic milieu clear glutamate, which protects neurons from excitotoxicity. Our recent studies revealed that chemogenetic activation of dorsomedial striatum (DMS) astrocyte enhances the activities of indirect medium spiny neurons (iMSNs), but not dMSNs in the DMS. The DMS is known to regulate goal-directed actions as lesions or inactivation of DMS render actions habitual instead of goal-directed. Conversely, the dorsolateral striatum (DLS) is necessary for habitual actions as lesions or temporary inactivation of DLS bias behavior towards goal- directed actions. Since GABAergic iMSNs project to external globus pallidus (GPe), we also examined the role of astrocyte in the GPe. Interestingly, both chemogenetic astrocyte activation of DMS and GPe promotes transition from habitual to goal-directed ethanol-seeking behaviors. However, the precise role of astrocytes in the DMS-GPe or DLS-GPe circuits in regulating habitual ethanol seeking behavior has not been explored. Based on our findings, we hypothesize that astrocyte activities differentially regulate MSNs activities in the DMS and DLS, thereby determine goal-directed and habitual ethanol-seeking behaviors. To investigate this hypothesis, we propose three aims. First, we will determine how activation of astrocyte activities differentially regulates the alcohol-induced changes in glutamatergic and GABAergic signaling of the DMS and DLS. Second, we plan to examine the role of DMS and DLS astrocyte activation in goal- directed or habitual ethanol-seeking behaviors. Finally, we will investigate the effect of ablation of DMS- GPe and DLS-GPe circuits in goal-directed or habitual ethanol-seeking behaviors. Our study will elucidate the neural mechanisms encoding goal-directed and habitual ethanol-containing reward-seeking behaviors. We will provide a rational path for the development of new therapeutic methods for the treatment of AUD.
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0.954 |
2021 |
Choi, Doo-Sup Trushina, Eugenia |
R01Activity Code Description: To support a discrete, specified, circumscribed project to be performed by the named investigator(s) in an area representing his or her specific interest and competencies. |
Chronic Alcohol Exposure and Pathophysiology of Alzheimer's Disease.
Project Summary Repeated and excessive alcohol consumption is known to lead to brain damage, and may increase the risk of developing Alzheimer?s Disease (AD). A recent study demonstrated that light-to-moderate alcohol consumption, as low as eight drinks a week, may be associated with cognitive decline and AD. Not surprisingly, alcohol consumption appears to be more harmful to the elderly. Since alcohol metabolism rates decline with age, it could have a greater effect and may exacerbate underlying cognitive problems. However, the limitation of these epidemiological studies includes their observational nature without a mechanistic investigation of the ?cause and effect? on how alcohol may impact the AD development. Importantly, it is widely known that women are approximately twice as likely to develop AD. However, genetic and biological basis of the sex specific differences in AD is understudied. Therefore, it is essential to understand to what extent alcohol could exacerbate the development of AD depending on the starting age of alcohol consumption, sex, and genetic risk factors. Based on the in-depth expertise in alcohol use disorder (AUD) (Dr. Choi) and AD (Dr. Trushina), two PIs propose to conduct a collaborative research applying comprehensive approach to address these fundamental questions. Using two mouse models representing familial AD (APP/PS1) and late-onset sporadic AD (ApoE4KI), we will examine whether alcohol exposure has sex and/or age-dependent effect exacerbating the onset and development of AD in at-risk individuals. To investigate this hypothesis, we propose two specific aims. In the first aim, we will determine whether chronic alcohol exposure exacerbates AD-like behavioral and metabolic phenotype in APP/PS1 and ApoE4KI mouse models. In the second aim, we will determine the impact of chronic alcohol exposure on the pathophysiology and biomarkers of AD. The outcomes will be significant providing comprehensive data and critical biological evidence to establish the preclinical criteria and provide translatable information regarding the impact of alcohol on AD.
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0.954 |
2021 |
Choi, Doo-Sup |
R21Activity Code Description: To encourage the development of new research activities in categorical program areas. (Support generally is restricted in level of support and in time.) |
Neural Basis of Ethanol Withdrawal-Induced Sleep Disturbance
Project Summary In humans and rodents, abnormal sleep patterns are risk factors for excessive alcohol consumption. Alcohol-dependent subjects, both during a drinking period and during withdrawal, suffer from a multitude of sleep disruptions. During alcohol withdrawal, recovering alcohol-dependent patients commonly experience severe and protracted sleep disruptions manifested by profound insomnia along with excessive daytime sleepiness. Sleep disturbances during alcohol recovery can increase the risk of relapse to alcohol use. However, the neural mechanisms responsible for mediating the effects of ethanol on sleep remain largely unknown. Based on recent findings, we hypothesize that repeated ethanol exposure disrupts sleep patterns through the striato-basal forebrain (NAc-BF) circuit in sex-dependent manner. To test our hypothesis, we will 1) examine the effects of repeated ethanol-withdrawal on sleep disturbance patterns, 2) determine the activities of the NAc-BF circuit in ethanol withdrawal-induced sleep disturbance, and 3) Investigate the effects of the NAc-BF circuit manipulations in ethanol withdrawal-induced sleep disturbance. Our study will reveal neural basis of how NAc-BF circuits contribute to chronic ethanol- induced sleep disturbance. We expect to elucidate the sex-dependent sleep disturbance during the course of ethanol exposures. The outcomes of our study will be a critical research foundation for future R01 research to discover and comprehensively characterize neural circuits and molecular mechanisms underlying ethanol-induced sleep disturbance, which may translate into clinical studies and identify novel therapeutic targets.
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0.954 |