Kelly Cosgrove - US grants

DESCRIPTION This proposal was designed to allow for the investigation of treatments for alcoholism and the conditions under which these treatments may prove most effective. The experiments consist of examining the effectiveness of two pharmacological treatments, naltrexone, an opioid antagonist and bremazocine, a kappa opioid agonist, in reducing self- administration of oral ethanol by rhesus monkeys. Furthermore, it is possible that certain variables may influence may influence the effectiveness of treatment drugs. Therefore, the influence of an open versus closed economy on the effects of bremazocine will be investigated. An open economy allows for supplemented amounts of ethanol in addition to that which is earned, and in a closed economy the subject earns the entire amount. This paradigm allows for the investigation of the selectivity of treatment drugs. In addition, it is important to understand how ethanol-maintained behavior may differ as a function of sex. Thus, the effects of bremazocine and naltrexone on ethanol self-administration as a function of sex will be investigated.

[unreadable] DESCRIPTION (provided by applicant): This is a request for a Mentored Research Scientist Development Award (K01) for advanced training in research on the neurochemical underpinnings of tobacco smoking and the influence of sex and sex hormones using neuroreceptor-imaging technologies. Sex differences exist in a variety of behaviors related to tobacco smoking such as craving, sensitivity to cues, and treatment effects; however, the mechanisms underlying these differences are unclear. Understanding the neurochemistry mediating sex differences in tobacco smoking will lead to the development of much needed sex-specific treatments for smoking cessation. The primary focus of the proposed studies is training in neuroreceptor imaging using single photon emission computed tomography (SPECT) and positron emission tomography (PET) modalities to determine the influence of sex, sex hormones and tobacco smoking on nicotinic acetylcholine receptor (nAChR) expression. We propose to determine whether there are sex differences in agonist binding to the |32-nAChR by imaging healthy men and women nonsmokers, and healthy men and women smokers with women in different phases of the menstrual cycle using the p2-nAChR agonist radiotracer [123I]5-IA-85380 and SPECT. The training component includes supervised research, formal coursework in SPECT and PET theory and methodology, and advanced training in statistical parametric mapping. The multidisciplinary nature of this project, conducted under the mentorship of Drs. Julie Staley, Stephanie O'Malley, and Rich Carson, in collaboration with faculty specializing in SPECT and PET image analysis, pharmacokinetic modeling, radiochemistry, tobacco smoking, and clinical psychopharmacology will provide a valuable opportunity for the candidate to address issues regarding the effects of sex and hormones on nAChR expression in living humans. The project will enable the candidate to develop into an independent investigator in the application of imaging modalities to the investigation of the neurochemical mechanisms underlying substance disorders. The ultimate goal of these studies is to investigate differences in the brains of men and women tobacco smokers, which will provide information on why women often have a harder time quitting smoking than men. This will aid in the development of medications that are specifically designed to help both women and men quit smoking. [unreadable] [unreadable] [unreadable]

[unreadable] DESCRIPTION (provided by applicant): Tobacco Smoking, Genes & Nicotinic Receptors Habitual tobacco smoking is a complex trait with strong genetic influences. Genetic factors are estimated to account for 50-72% of the risk for developing nicotine dependence. The nicotinic acetylcholine receptor (nAChR) is the initial site of action of nicotine, the addictive chemical constituent of tobacco smoke and thus, is a primary candidate to carry genetic effects for tobacco smoking between generations. nAChR containing the 22-subunit (22-nAChR) in combination with 14 subunits are the most prevalent nAChR in brain, and are linked to the addictive properties of tobacco smoking. In our previous proposal, for aim 1, we demonstrated using [123I]5-IA 85380 SPECT imaging that these receptors are higher (26-36%) in the striatum, and throughout the cerebral cortex and cerebellum in tobacco smokers versus nonsmokers. For aim 2 we evaluated the normalization of the receptor over the first month of abstinence, and in addition, evaluated in smokers that were able to abstain from smoking for longer periods of time up to 12 weeks of abstinence. The findings from this aim were very heterogenous, with some subjects showing decreases ranging from 4% to 43% in nAChR availability over the first month of abstinence and others showing no change. We have hypothesized that the variability in the regulatory effects of habitual tobacco smoking on nicotinic receptor availability is genetically determined. In the present proposal, we seek to validate this hypothesis through the following specific aims: 1) to determine if 22-nAChR availability is genetically determined in European-American never smokers. 2) to determine if the adaptive increase in 22-nAChR availability in European-American smokers is genetically determined and 3) to determine if the change in 22-nAChR availability over the first month of abstinence in smokers is genetically determined. The findings from these studies may provide definitive genetic and neurochemical phenotypic evidence that will allow in future studies for smokers to be stratified and tested for responses to various smoking cessation treatments. PUBLIC HEALTH RELEVANCE: Smoking is the leading known cause of preventable death and disease. Despite the debilitating medical, economic and social costs of cigarette smoking, people continue to smoke. The persistence of this destructive behavior is a consequence of insufficient smoking cessation treatments to assist smokers in their efforts to quit smoking. The nicotinic acetylcholine receptor (nAChR) is a likely neurochemical substrate of the addiction to cigarette smoking. These studies will define the genes and brain chemicals that may help to design treatment studies that will ultimately help tailor smoking cessation treatments, they will decrease the incidence of smoking-related deaths and disease that plague the world today. [unreadable] [unreadable] [unreadable]

DESCRIPTION (provided by applicant): Tobacco smoking continues to be a major health problem, and existing pharmacotherapies have only modest effects over placebo. The initial reinforcing effects and continued use of tobacco smoke are likely driven in part by nicotine-induced dopamine release. However, there remains inconsistency in the literature regarding the ability to accurately measure nicotine-induced dopamine release with PET brain imaging. The development of the dopamine D2/3 radiotracer [11C]PHNO has advantages over other dopamine D2 receptor ligands because it is an agonist and measures the high affinity, functionally active D2 receptors and not the low affinity D2 receptors. This has been recently shown to produce an increased sensitivity over other PET ligands to measure changes in synaptic dopamine levels and thus provides a novel paradigm to investigate nicotine-induced dopamine release. Additionally, rimonabant, a cannabinoid receptor antagonist, has shown promise both preclinically and clinically as a smoking cessation medication. Research investigating the relationship between the dopaminergic and endocannabinoid systems will be critical to expand our understanding of tobacco dependence, and to develop novel pharmacotherapies that utilize the knowledge of this relationship. To begin to address this relationship, we propose the following Aims. In Aim 1, we propose to examine nicotine-induced dopamine release with the agonist radiotracer [11C]PHNO and PET brain imaging. Specifically, 6 nonhuman primates will participate in [11C]PHNO PET scans in which they will be given an injection of nicotine (0.06 mg/kg, IV) and dopamine release will be measured. We hypothesize that nicotine will result in significant dopamine release, e.g., equal to or greater than a 10% change in ligand binding. In Aim 2, we propose to use the CB1 receptor antagonist, rimonabant, to block the effect of nicotine on dopamine release. The same 6 nonhuman primates from Aim 1 will participate in [11C]PHNO PET scans in which they will first be given rimonabant (1 mg/kg, IV), and then given an injection of nicotine (0.06 mg/kg, IV). We hypothesize that rimonabant will fully block (e.g., by approximately 80%) the nicotine-induced dopamine release. The findings from this study will advance the understanding of the neurochemical mechanisms that underlie tobacco smoking. The proposed experiments will directly impact public health by delineating a brain mechanism underlying a medication that may be useful in smoking cessation. PUBLIC HEALTH RELEVANCE: The proposed experiments will directly impact public health by developing a novel paradigm to investigate nicotine-induced dopamine release in vivo. These studies will examine the effects of nicotine and the treatment drug rimonabant in the brain to determine the interaction of these drugs on brain chemistry. These studies will ultimately provide information on how to more successfully treat tobacco smoking.

DESCRIPTION (provided by applicant): Alcohol dependence and tobacco smoking are highly associated, yet studies examining the underlying neurochemistry are scarce. In humans, tobacco smoking appears to regulate the availability of the GABAA- BZR during the recovery from alcohol dependence. Clinical data suggest increased GABAA-BZR availability in alcohol dependent nonsmokers during acute withdrawal that is suppressed in alcohol dependent smokers. Additionally, there appears to be decreased GABAA-BZR availability during prolonged alcohol withdrawal; yet this has not been systematically studied. The purpose of this project is to determine the effects of withdrawal from chronic orally-delivered ethanol versus chronic co-administration of ethanol and nicotine on the GABAA- BZR in brain over time using [123I]iomazenil and single photon emission computed tomography (SPECT). We will also examine changes in GABAA-BZR availability during withdrawal from both ethanol and nicotine simultaneously, versus withdrawal from ethanol in the presence of continued nicotine exposure to model changes in GABAA-BZR in humans that quit drinking and smoking simultaneously vs. quitting drinking while continuing to smoke. We will obtain scans in 50 adolescent animals (n=10 per group). All animals will receive 2 scans at baseline, e.g., test-retest. Group 1 will self-administer chronic ethanol for 24 weeks and will be imaged at 1 day, 8 days and 12 weeks withdrawal. Group 2 will self-administer chronic nicotine for 24 weeks and will be imaged at 1 day, 8 days and 12 weeks withdrawal. Group 3A will self-administer ethanol plus nicotine for 24 weeks and will be scanned at 1 day, 8 days and 12 weeks withdrawal from both ethanol and nicotine. Group 3B will self-administer ethanol plus nicotine for 24 weeks and will be imaged at 1 day, 8 days and 12 weeks withdrawal from ethanol, but will continue to self-administer nicotine during this withdrawal period. Group 4, a control condition, will self-administer saccharin for 24 weeks and will be imaged at 1 day, 8 days and 12 weeks after termination of saccharin. MRI scans will be obtained to track changes in brain gray and white matter and cerebrospinal fluid (CSF). We hypothesize that there will be 1) increased GABAA-BZR availability compared to baseline and controls during acute ethanol withdrawal and decreased GABAA-BZR availability compared to baseline and controls at 12 weeks ethanol withdrawal; 2) no change in GABAA-BZR availability compared to baseline or controls during nicotine withdrawal; and, 3) the combination of ethanol and nicotine will result in decreased GABAA-BZR availability compared to ethanol alone, i.e., nicotine will suppress the ethanol-induced increase, and withdrawal from ethanol into the presence of nicotine will result in a greater suppression of increased GABAA-BZR availability compared to withdrawal from ethanol and nicotine simultaneously. The findings from this study will advance the understanding of the neurochemical mechanisms that underlie the high comorbidity of alcohol and nicotine dependence and will have direct clinical implications for the treatment of alcohol dependence in both smokers and nonsmokers. PUBLIC HEALTH RELEVANCE: The proposed experiments will directly impact public health by delineating a brain mechanism, the GABAA- benzodiazepine receptor, which is involved in the recovery from alcohol dependence and in the interaction of alcohol dependence and tobacco smoking. These studies will examine the withdrawal from both alcohol and nicotine to determine the interaction of these drugs on brain chemistry. These studies will ultimately provide information on how to more successfully treat these costly addictions.

DESCRIPTION (provided by applicant): Nicotinic Acetylcholine Receptors in Schizophrenia Schizophrenic patients have among the highest rates of tobacco smoking and nicotine is thought to alleviate some of the symptoms associated with schizophrenia. Chronic nicotine exposure up regulates nicotinic agonist binding to brain nicotinic acetyl choline receptors (nAChR). In postmortem studies, there are region-specific increases in high affinity nAChR binding in healthy human tobacco smokers but not in schizophrenic smokers. While these data suggest high affinity nAChR dysregulation in schizophrenic smokers, there are no in vivo data showing nAChR dysregulation in schizophrenia or how it might relate to smoking or the symptoms (cognitive deficits) associated with schizophrenia. Using [123I]5-IA-85380 (5-IA) and SPECT imaging we have recently shown that consistent with post mortem data, healthy smokers have 30% higher 22-nAChR availability vs. never smokers. Consistent with post-mortem studies in our pilot data schizophrenic smokers (SS) (n=7;6 medicated and 1 unmedicated) show region specific reductions in brain [123I]5-IA uptake relative to healthy smokers (HS) regardless of medication status. These findings may reflect a failure to upregulate 22-nAChR in schizophrenic smokers. Further, SS show higher [123I]5-IA uptake compared to healthy never smokers (HNS) while schizophrenic nonsmokers (SNS) (n=4) show lower [123I]5-IA uptake in the thalamus, but also in the parietal, frontal, and occipital cortices compared to HNS. Memory and attention were disrupted by smoking abstinence and restored by the resumption of smoking. Aims: Using SPECT and 5-IA, this proposal aims to determine if 1A) SS show reduced region specific 22- nAChR availability relative to HS;1B) unmedicated SS show reduced region specific 22-nAChR availability relative to HNS;1C) there are differences in 22-nAChR availability between medicated and unmedicated SS;2) SNS show lower 22-nAChR availability compared to HNS. In addition we plan to explore 1) differences in regional 22 nAChR availability between medicated SS vs. medicated SNS;2) the relationship between cognitive test performance and regional 22-nAChR availability;and 3) the effects of smoking abstinence and smoking resumption on cognitive test performance. Methods: HS and SS (medicated and unmedicated) will achieve 5 days of confirmed abstinence with a combined strategy of counseling and contingency management, and hospitalization for only the schizophrenic smokers. Matched HNS and SNS will also be studied. All subjects will be studied using SPECT and 5-IA followed by an MRI for coregistration. Cognitive testing (verbal memory, attention, working memory and selective attention) will be assessed while smoking as usual, 24 hours after quitting, 5 days abstinence and if subjects resume smoking. Cognitive data will be correlated with regional brain [123I]5-IA uptake (VT and VT'). PUBLIC HEALTH RELEVANCE There are high rates of smoking in individuals with schizophrenia and smoking (nicotine) may alleviate certain symptoms of schizophrenia. This has led to the suggestion that alterations in the nicotine receptor system may contribute to the high rates of smoking (addiction) in schizophrenia and some of its symptoms. This grant application proposes to use brain imaging to study the nicotine receptor system in schizophrenia.

DESCRIPTION (provided by applicant): This K02 application proposes support essential for my career development as a newly independent researcher in brain imaging of addiction and tobacco smoking. Through a K01 funded by NIDA, I attained considerable expertise in brain imaging of tobacco smokers, with a focus on sex differences. I have demonstrated considerable research productivity as evidenced by my increasing number of peer reviewed publications and current grant funding including being principal investigator on two R01s. This K02 award is vital for providing focused research time and for facilitating my maturation into a fully-independent investigator. My current career goal is to use SPECT and PET imaging to examine brain receptor changes during acute and prolonged abstinence from tobacco smoking and to determine biomarkers that may modulate these receptor changes and thus impact tobacco smoking cessation efforts. Included in the proposal is a rigorous 5-year career development training plan that fills important gaps and complements my current expertise in SPECT/PET neuroreceptor imaging. Specifically, I plan to broaden my knowledge in the three areas of genetics, cognition and fMRI, so that I can integrate them in my research on tobacco smoking and addiction in order to have a greater impact on future treatment. Intensive training is provided by an integrated curriculum of intramural coursework, extramural short courses, three individualized preceptorships, interactive symposia, and research-related organizational meetings. A primary NIDA funded research study (R01) is included that examines genetic influences on nicotinic acetylcholine receptor availability in habitual tobacco smokers and nonsmokers. We have previously demonstrated using [123I]5-IA-85380 and SPECT brain imaging that beta2-subunit containing nicotinic acetylcholine receptors (beta2-nAChRs) are higher (26-36%) in the striatum, and throughout the cerebral cortex and cerebellum in tobacco smokers versus nonsmokers and that it takes up to 6-12 of abstinence for these receptors to return to control levels. The findings from the latter study were heterogeneous, with some subjects showing decreases of up to 17% over abstinence and others showing minimal change, e.g., 4%. The goal of the current study is to determine whether this individual variability in beta-nAChR availability during acute and prolonged abstinence is genetically mediated. In the present proposal, we aim to validate this hypothesis through the following specific aims: 1) to determine if beta2-nAChR availability is genetically determined in European-American (EA) never smokers, 2) to determine if the adaptive increase in beta2-nAChR availability in EA smokers is genetically determined and 3) to determine if the change in beta2-nAChR availability over the first 6-8 weeks of abstinence in EA smokers from Aim 2 is genetically determined. The focus is on 2 genes that have been associated with nicotine dependence, the CHRNA4 and ANKK1. The findings from these studies may provide definitive genetic and neurochemical evidence that will allow in future studies for smokers to be stratified and tested for responses to various smoking cessation treatments.

DESCRIPTION (provided by applicant): Tobacco Smoking, Genes & Nicotinic Receptors Habitual tobacco smoking is a complex trait with strong genetic influences. Genetic factors are estimated to account for 50-72% of the risk for developing nicotine dependence. The nicotinic acetylcholine receptor (nAChR) is the initial site of action of nicotine, the addictive chemical constituent of tobacco smoke and thus, is a primary candidate to carry genetic effects for tobacco smoking between generations. nAChR containing the 22-subunit (22-nAChR) in combination with 14 subunits are the most prevalent nAChR in brain, and are linked to the addictive properties of tobacco smoking. In our previous proposal, for aim 1, we demonstrated using [123I]5-IA 85380 SPECT imaging that these receptors are higher (26-36%) in the striatum, and throughout the cerebral cortex and cerebellum in tobacco smokers versus nonsmokers. For aim 2 we evaluated the normalization of the receptor over the first month of abstinence, and in addition, evaluated in smokers that were able to abstain from smoking for longer periods of time up to 12 weeks of abstinence. The findings from this aim were very heterogenous, with some subjects showing decreases ranging from 4% to 43% in nAChR availability over the first month of abstinence and others showing no change. We have hypothesized that the variability in the regulatory effects of habitual tobacco smoking on nicotinic receptor availability is genetically determined. In the present proposal, we seek to validate this hypothesis through the following specific aims: 1) to determine if 22-nAChR availability is genetically determined in European-American never smokers. 2) to determine if the adaptive increase in 22-nAChR availability in European-American smokers is genetically determined and 3) to determine if the change in 22-nAChR availability over the first month of abstinence in smokers is genetically determined. The findings from these studies may provide definitive genetic and neurochemical phenotypic evidence that will allow in future studies for smokers to be stratified and tested for responses to various smoking cessation treatments. PUBLIC HEALTH RELEVANCE: Smoking is the leading known cause of preventable death and disease. Despite the debilitating medical, economic and social costs of cigarette smoking, people continue to smoke. The persistence of this destructive behavior is a consequence of insufficient smoking cessation treatments to assist smokers in their efforts to quit smoking. The nicotinic acetylcholine receptor (nAChR) is a likely neurochemical substrate of the addiction to cigarette smoking. These studies will define the genes and brain chemicals that may help to design treatment studies that will ultimately help tailor smoking cessation treatments, they will decrease the incidence of smoking-related deaths and disease that plague the world today.

DESCRIPTION (provided by applicant): Alcohol dependence affects 18 million Americans. Treatments for alcohol dependence show only modest efficacy, and better treatments are needed. Systemic inflammation, neuroinflammation, and microglial activation may play a role in the pathogenesis of alcoholism. Our work and that of others has shown that systemic inflammation has important effects on the brain, including effects on motivation and emotion, and activation of microglia. In rodents, chronic alcohol exposure leads to activation of microglia, which release substances that cause neuronal dysfunction and death, e.g. inflammatory cytokines. Activation of microglia by pro-inflammatory signals, which are increased systemically in alcoholism, may be a mechanism through which alcohol interferes with neuronal function, thus contributing to craving and continued drinking. Rodent and postmortem human studies suggest this activation is a consequence of chronic alcohol drinking and that it is persistent. Positron emission tomography (PET) imaging of the Translocator Protein (TSPO) is used to measure the presence of activated microglia in the human brain in vivo. We found robust, higher binding of the TSPO radiotracer [ 11C]PBR28 in an alcohol-dependent vs. control subject, suggesting that PET imaging can be used to detect microglial activation in individuals with alcoholism in vivo. We propose to extend this exciting finding and assess microglial activation in alcohol-dependent individuals using [11C]PBR28, which has the highest specificity for TSPO of currently-available TSPO tracers, and the High Resolution Research Tomograph, the highest resolution human PET camera available. Alcohol-dependent (AD) subjects (n=15) will be matched with healthy control (HC) subjects (n=15) for age, sex, race and education level. A PET scan will be performed within 24 hours of their last drink. HC subjects will be assessed and scanned as outpatients. A subset of AD subjects (n=8) will be admitted to the inpatient research unit and will have a second PET scan 7 days later to assess short-term persistence of microglial activation. Behavioral ratings (craving, cognitive function, depression and anxiety) and blood cytokine levels will be obtained. [11C]PBR28 will be injected as a bolus, and a two-hour emission scan will be acquired on the HRRT. Volume of distribution (VT) will be estimated from the model fits for each region of interest and will be correlated with behavioral measures and cytokine levels (TNFalpha, IL-6). We hypothesize that as a consequence of chronic alcohol drinking, AD subjects will have significantly higher (>15%) levels of PBR28 binding vs. controls within 24 hours of the last drink and that this higher microglial activation will persist and remai higher 7 days later. If AD subjects have higher microglial activation, and this contributes to the core behaviors of alcoholism, pharmacological interventions that reduce microglial activation and neuroinflammation may be tested for the treatment of alcoholism.

? DESCRIPTION (provided by applicant): One of the biggest issues in treating tobacco smoking dependence is the high rate of relapse during early abstinence, which is primarily due to the powerful withdrawal syndrome including cognitive impairment, intense craving, and a poor mood. The neurotransmitters acetylcholine (ACh) and dopamine (DA) are known to mediate the reinforcing effects of smoking and they also drive the primary behavioral withdrawal symptoms; however, the very basic cholinergic and dopaminergic brain mechanisms that underlie withdrawal and relapse in tobacco smokers are unknown. Nicotine, the primary addictive chemical in tobacco smoke, binds to neuronal beta2 subunit-containing nicotinic acetylcholine receptors (?2*-nAChRs) leading to widespread changes in neurotransmitter levels including DA, and an increase in the number of ?2*-nAChRs throughout the brain. We have previously shown that there are dynamic changes in numbers of ?2*-nAChRs over abstinence; but we do not know the functional significance, i.e., if ACh neurotransmission is altered over the course of abstinence, and if altered ACh levels are associated with cognitive dysfunction and relapse vulnerability. A substantial preclinical literature demonstrates that nAChRs and the cholinergic system dynamically control the mesolimbic DA system by enhancing, inhibiting and filtering striatal DA release. A primary issue in tobacco smoking withdrawal is the intense craving in response to cues and we know that DA regulates the salience of stimuli and underlies cue-reactivity. Few studies have systematically examined cue-induced reactivity over prolonged abstinence periods and none have examined the association between DA signaling and cue-induced reactivity and the relationship to relapse in human smokers. The overall goal of this proposal is to uncover the molecular mechanisms underlying tobacco smoking withdrawal, and the relationship to withdrawal-related behaviors (i.e., cognitive function, mood, cue-reactivity) and relapse. We now have the tools to probe both ACh and DA neurotransmission in the human brain with positron emission computed tomography (PET). We will measure physostigmine-induced elevations in synaptic ACh with [18F]Flubatine and amphetamine-induced DA release with [11C]PHNO, within-subject, in nonsmokers and in tobacco smokers during early and prolonged withdrawal. Further, we will investigate whether alterations in ACh and DA levels differentially affect cognitive function (attention, concentration, cue reactivity) and mood in smokers vs. nonsmokers and whether changes in synaptic ACh or DA are predictive of success in maintaining abstinence for up to 6-8 weeks. If there are predictive relationships between ACh and DA function, cognitive domains and relapse, the cognitive measures may ultimately serve as biomarkers of the imaging measures to direct individualized treatment strategies toward restoration of the cholinergic or dopaminergic systems based on the identified impairments. An elucidation of the mechanisms underlying tobacco smoking withdrawal may ultimately lead to novel and more targeted treatment, and thus have a major impact on public health.

Project Summary Nearly 9 in 10 Americans will be exposed to trauma in their lifetime and 1 in 10 will develop post-traumatic stress disorder (PTSD), which is characterized by elevated threat (e.g., intrusions, anxious arousal), loss (e.g., anhedonia, negative affect) and neurocognitive (e.g., verbal learning, attention) symptoms. Individuals with PTSD have elevated rates of physical health conditions, as well as functional impairment, with loss symptoms in particular contributing to decreased quality of life. The immune system is responsible for maintaining health, which includes mounting a response to physical (e.g., virus, injury) and psychological (e.g., stress) insults, as well as modulating the progression of neurodegenerative disorders such as Alzheimer?s disease. All of these - physical health conditions, psychological distress, and neurodegenerative disorders - are more prevalent in individuals with than without PTSD. There are peripheral immune system abnormalities in PTSD; however, no known study has evaluated the role of the neuroimmune system in PTSD. In the healthy immune system, the response of the central nervous system to an insult or damage is mediated by the activation of microglia, which carry out repair functions. However, excessive activation can lead to neuronal dysfunction and damage through the release of inflammatory cytokines and stress hormones, and may contribute to neurodegeneration, such as that found in individuals with PTSD. When microglia are activated, there is a robust increase in the expression of translocator protein (TSPO). Positron emission tomography (PET) radiotracers such as [11C]PBR28, which bind to TSPO, can therefore be used to measure levels of activated microglia in vivo. In addition to measuring levels of activated microglia in individuals with PTSD (vs. controls), we can also challenge the immune system by administering E. Coli lipopolysaccharide (LPS), a potent immune activator and measure increases in activated microglia within subject. We have recently demonstrated robust LPS- induced increases in activated microglia, and concomitant increases in peripheral inflammatory cytokines, and associated mood, anxiety, and neurocognitive symptoms in humans. In the proposed study, we will systematically evaluate the relationship between ?neuroinflammation?, as assessed with [11C]PBR28 and PET, and the expression of threat, loss, and neurocognitive symptoms in 80 trauma-exposed individuals presenting with the full dimensional spectrum of PTSD symptoms. Specifically, we will (1) determine whether individuals with PTSD have higher levels of activated microglia compared to trauma-exposed controls; (2) use a novel neuroimmune ?stress test? to determine whether individuals with PTSD have a dysfunctional neuroimmune response to systemic administration of LPS; and (3) determine the role of activated microglia in mediating the relationship between peripheral inflammatory markers (e.g., TNF-?), and trauma-related symptoms to discover potential biomarkers of PTSD. Results of this study will yield insight into novel, mechanism-based, and treatable neuroimmune mechanisms implicated in PTSD and related syndromes.

Project Summary / Abstract The United States is in the midst of an opioid epidemic. Approved treatments for opioid use disorder (OUD) show only moderate efficacy, and most patients relapse early in treatment. There has been increased interest in the role of the immune system in OUD in terms of both pathophysiology and treatment. Opioids are known to activate microglia ? the brains' innate immune cells ? which leads to an immediate immune response; however, with chronic opioid use, the peripheral immune system becomes suppressed. Persistent, chronic immune activation becomes pathological, and can lead to long-standing, widespread alterations in reward and neurocognitive processes, which negatively impact treatment outcome. Further, while studies have consistently shown that chronic opioid abuse leads to suppressed peripheral immune function, it is not known whether chronic opioid abuse impacts the neuroimmune system. We have developed and validated the tools to measure a marker of microglia in living humans, specifically positron emission tomography (PET) imaging with the radiotracer [11C]PBR28. The overall goal of the proposed project is to use these tools to measure microglia levels in living individuals with OUD compared to healthy controls (Aim 1), and to determine relationships between microglia levels and objective measures of reward processing and neurocognitive function (Aim 2). Findings from this high-risk exploratory R21 proposal will improve our understanding of the neuroimmune mechanisms underlying OUD and its associated clinical correlates. These results have the potential to uncover a novel and treatable neuroimmune mechanism of OUD, and may guide the use of immunomodulatory agents in the clinical treatment of OUD.

ABSTRACT: It is increasingly clear that women are more vulnerable than men to some of the negative effects of chronic alcohol consumption, including immune system dysfunction and neurodegeneration. Project 2 will focus on identifying sex differences in biomarkers of alcohol-induced neurodegeneration that lead to neural adaptations that drive the addiction cycle. In the current study, we will collect pilot data to examine whether chronic alcohol consumption is associated with reductions in microglia (Aim 1) and synaptic density (Aim 2) and if the impairment varies by sex.

It is increasingly clear that women are more vulnerable than men to some of the negative effects of chronic alcohol consumption, including immune system dysfunction and neurodegeneration. This is important since the rates of problem drinking in women are rapidly increasing, and the currently available treatments are only moderately effective. There is mounting evidence that men and women drink for different reasons. Women tend to drink to regulate stress and negative affect, whereas men report drinking for alcohol-related positive reinforcement. This provides an important opportunity to explore sex-appropriate treatments. In particular, we need to understand the neurochemical mechanisms that underlie and contribute to these behavioral sex differences in order to provide new treatment targets for medication development. In this proposed Yale- SCORE, Project 2 will focus on identifying sex differences in biomarkers of alcohol-induced neurodegeneration that lead to neural adaptations that drive the addiction cycle. Using state-of-the-art positron emission tomography (PET) technology, we will examine sex differences in levels of microglia and synaptic density in living individuals with alcohol use disorder (AUD). Microglia, the brains? resident immune cells, are involved in a variety of physiologic and pathologic processes, most notably surveying the brains? environment for danger and carrying out necessary repair functions. Alcohol initially activates microglia but chronic consumption has been shown to suppress both peripheral and neuroimmune systems. We have preliminary data suggesting more severe neuroimmune suppression in women vs. men with AUD, which may underlie the findings that women with AUD exhibit worse mood and neurocognitive dysfunction than men. Microglia are also critical for supporting synaptic structure and function and conversely, microglial dysfunction leads to deficits in synapse number and contributes to mood and cognitive impairment. However, the relationships between microglia, synaptic density, stress, mood, and neurocognitive function in living humans with AUD are not known. In the current study, we will examine whether chronic alcohol consumption is associated with reductions in microglia (Aim 1) and synaptic density (Aim 2) and if the impairment varies by sex. We hypothesize that women with AUD evidence greater deficits in microglia and synaptic density, which underlie sex differences in stress reactivity, negative affect, and neurocognitive dysfunction in AUD (Aim 3). Thus, the proposed project has the potential to measure, for the first time, sex differences in neurochemical markers of neurodegeneration in the living brain of patients with AUD and their relationship to critical clinical outcomes. These findings will advance the alcohol field by uncovering novel, sex-appropriate treatment targets.

PROJECT SUMMARY Few effective interventions exist for neurodevelopmental disorders (NDDs), which are associated with significant impairment, high rates of disability, and substantial public health costs. The prevalence of NDDs has increased considerably over the past two decades, and children with NDDs make up the largest proportion of youth that seek mental health treatment. Thus, novel approaches for understanding NDDs and identifying potential treatment targets for these disorders are needed. NDDs often have comorbid presentations and shared symptomatology (e.g., impaired social functioning), which suggests that using a transdiagnostic approach to study NDDs may be informative. This approach could reveal modifiable factors and underlying neurobiological mechanisms that could be targeted through intervention to reduce neurodevelopmental symptomatology. Social connectedness (i.e., extracurricular involvement, family dynamics, and relationships with peers and parents) may be a salient protective factor for youth with neurodevelopmental symptomatology. An important neural correlate for social functioning appears to be functional connectivity within the salience network (SN), which is involved in detection of relevant stimuli (e.g., changes in other's emotional expressions).Thus, social connectedness and related connectivity within the SN may be predictive of neurodevelopmental outcomes. The potential protective role of these factors may be particularly salient during adolescence, which is a vulnerable period for many of the negative outcomes associated with NDDs. The proposed longitudinal project will capitalize on the multi-level framework of the Adolescent Brain Cognitive Development (ABCD) study by using psychosocial, functional neuroimaging, and cognitive data from two timepoints (i.e., baseline and one-year follow-up) to assess neurodevelopmental functioning in a sample of >11,500 youth in early adolescence. The project will be conducted at the Laureate Institute for Brain Research, which is an ABCD study site. The aims of the proposed project are threefold: to determine whether 1) social connectedness is associated with SN functional connectivity cross-sectionally; 2) social connectedness predicts future neurodevelopmental function; and 3) SN functional connectivity predicts future neurodevelopmental function. These aims will be assessed using linear mixed effects models with relevant covariates included (e.g., baseline neurodevelopmental function, youth ethnicity, youth gender, and family income). The proposed study has an exploratory aim of utilizing a data-driven, machine learning approach to identify additional modifiable factors (e.g., sleep, physical activity, screen time) that predict future neurodevelopmental function. The project is novel in that it takes a transdiagnostic approach to studying NDDs, it is longitudinal, and it has the potential for replication and extension as future data are released. Results from the project could have meaningful clinical relevance with the potential for identifying treatment targets for future interventions aiming to improve neurodevelopmental symptomatology in early adolescence.

The goal of the Translational Alcohol Research Program (TARP) is to facilitate the ability of emerging post-doctoral researchers to bridge the gap in the application of knowledge gained from basic to clinical and social behavioral science research in alcohol use disorders (AUD) and alcohol- related liver disease (ALD). Both AUD and ALD are major public health problems and they should be considered together in the diagnosis and management of alcohol abuse and alcoholism. There is a gap in the application of knowledge f rom basic science studies to clinical models. This is particularly concerning given the establishment of a new generation of approaches (e.g., genomic, whole-body imaging) that allow the application of a `systems' approach to the study of AUD and ALD. It is of critical importance that future investigators are able to exploit these new research tools and approaches to accelerate the discovery and development of new treatments for ALD and AUD. The TARP is designed to improve clinical treatment of AUD and ALD by increasing the availability of appropriately-trained young scientists who are conversant in basic and clinical sciences and able to comfortably traverse the translational gap between these sciences. It is a two-year program offered by the Yale Schools of Medicine and Public Health and provides six post-doctoral trainees the opportunity to devote full-time effort during the initial phase of their careers to developing the skills and experience needed to become independent researchers in the field of translational research in AUD and ALD. The TARP has four main ?content areas? viz. Reward Mechanisms; Stress and Negative Affect; Comorbidity (psychiatric and medical); and Alcoholic Liver Disease. The affiliation of TARP faculty with the NIAAA-funded Center for the Translational Neuroscience of Alcoholism and/or the Yale Liver Center enables the TARP trainees to conduct research that readily gravitates between preclinical projects (?bench?) and clinical and population health studies (?bedside? and ?community?). Applicants will be MD or PhD post-doctoral candidates, trained in specialties including psychiatry, internal medicine, clinical psychology, public health, epidemiology, pharmacology, toxicology, or neuroscience. The TARP includes: 1) individualized, team- mentored research training, which includes successful completion of a translational-research project, 2) a core curriculum, including seminars on preclinical and clinical research and treatment, the medical consequences of excessive alcohol consumption, hepatology, metabolomics, biostatistics, responsible conduct of scientific research, and grant writing, 3) an individualized training and development plan (including participation in seminars of interest in associated departments and centers), 4) clinical and/or basic science training, and 5) training in effective communication and teaching. Upon completion, TARP graduates will be equipped to establish independent careers in translational research in AUD and ALD.