Shane A. Perrine - US grants

DESCRIPTION (provided by applicant): This K0I proposal is intended to provide support and protected time for the PI to execute a research plan designed as both an original scientific investigation as well as a training vehicle. The research plan aims to investigate potential associations between stimulant-induced behaviors and the attendant neurochemical profile determined with proton magnetic resonance spectroscopy ('HMRS). It is anticipated that the PI will acquire the skills to become an independent neuroscientist and ultimately achieve the long-term goal of a tenure-track academic appointment studying addiction neurobiology. Training and research activities are under the mentorship of Matthew P. Galloway, Ph.D. The career development plan includes seminar series, didactics, scientific meetings, manuscript reviewing/writing, responsible research conduct, and enhanced research skills. The research plan will study the behavioral and neurochemical dose-effects of MDMA (3,4 methylene-dioxymethamphetamine; ecstasy) as well as clinically-relevant factors that may influence MDMA-dependent outcomes. A specialized version of 'HMRS at 11.7 T will be used to measure regional GAB A, N-acetylaspartate, glutamate, as well as a host of other MR-visible neurochemical levels. HPLC will be used to measure monoamines and ELISA for blood corticosterone. Neurochemical effects will be measured in rats previously tested for locomotor, anxiety, and depression-like behaviors following MDMA. To assess predisposing factors, the effects of MDMA following repeated unpredictable stress or cannabis pretreatment will be studied. Also, the longitudinal effects of MDMA on in vivo 'HMRS will be explored in collaboration with co-mentor Gregory J. Moore, M.D. Ph.D. Since MDMA is neurotoxic to serotonin neurons, polydrug use and comorbid psychiatric conditions complicate clinical investigations and repeated MDMA use is associated with cognitive deficits in humans, the proposed research is highly relevant to public health. Moreover, relating MDMA's effects on behavior and monoamines to 1HMRS profiles has direct translational potential.

Project Summary / Abstract Cocaine addiction is a debilitating mental health disorder that interferes with an individual?s well-being, disrupts relationships, and burdens society. Cocaine, like other drugs of abuse, hijacks the brain?s reward center, producing enduring changes in brain regions, such as the nucleus accumbens (NAc), that perpetuate the cycle of addiction. Preclinical studies show that cocaine and other psychostimulants act as general enhancers of gene expression and that histone deacetylases (HDACs) in the NAc play a key role in the development of cocaine addiction. However, neurobiological understanding of the role of specific HDACs in these processes is limited and there are few in vivo studies on these targets. In response to the need for such studies, this proposal integrates state-of-the-art small animal positron emission tomography (PET) techniques with a model of cocaine self-administration (coc-SA) to study the role of NAc HDAC Class IIa (HDAC5) enzymatic activity during cocaine taking and seeking behaviors. The combination of in vivo neuroimaging and behavioral neuroscience methods in a longitudinal (repeated-measures) design presents an opportunity to advance understanding of the role of epigenetic activity in the NAc during the 4 phases of coc-SA, including acquisition, maintenance, extinction, and reinstatement. Our overall hypothesis is that cocaine will decrease the enzymatic activity of HDAC Class IIa proteins in the NAc, which will statistically explain increases in cocaine taking and seeking behaviors. Three aims will test this hypothesis. (1) Determine HDAC Class IIa enzymatic activity in the NAc using PET imaging and a novel substrate-based PET ligand at baseline and during the phases of coc-SA. (2) Determine the changes in HDAC Class IIa enzymes and protein targets in the NAc at the different phases of coc-SA using immunohistochemistry. (3) Determine the effect of nuclear HDAC5 in the NAc on class IIa HDAC enzymatic activity during cocaine seeking behavior. The combination of non-invasive PET assays with behavioral neuroscience methods to study the role of HDAC Class IIa enzyme activity in the NAc during cocaine taking and seeking behaviors provides a unique strategy to study the neurobiological mechanisms that underlie the stages of addiction. The proposed studies of this application will deliver translational knowledge that addresses theoretical and neurobiological gaps in our understanding of the role of epigenetics in cocaine addiction. This knowledge will aid in the development of novel neurotherapeutics that target epigenetic regulators and treat this devastating mental health disorder.

Project Summary ? Abstract Current neuroimaging methods to assess brain function are limited by poor spatial and temporal resolution as well as confounding vascular effects. This is particularly concerning for vasoactive drugs of abuse including fentanyl (FTY) that causes vasodilation. Also, current tools only indirectly measure neuronal activity likely missing patterns of neurons (i.e. neuronal ensembles) that are responsible for specific behaviors. FTY use significantly contributes to opioid overdoses in the United States and it is being abused by a large number of Americans. Yet, researchers know relatively little about this synthetic opioid agonist and assume it acts the same as other opioids and drugs of abuse on brain function. Research in animals and humans has shown that dysfunction of the prefrontal cortex (PFC) is a hallmark of drugs of abuse including opioids, and this dysfunction in the PFC is thought to contribute to compulsive drug taking behaviors. The technical limitations of current neuroimaging techniques and misassumption that FTY acts similar to other opioids and drugs of abuse on brain function present major research gaps that this grant proposal aims to address. Using photoacoustic imaging (PAI), a novel optical neuroimaging technique, combined with a Fos-LacZ transgenic rodent model, we propose a highly innovative project to study Fos-based neuroactivity, hemodynamics, and vascularization in female and male rats engaging in FTY self-administration (FTY-sa; i.e. FTY taking behavior). Our overall hypothesis is that PAI with multi-wavelength analysis in female and male Fos-LacZ transgenic rats provides a model system to study neuronal activity, vascularization and hemodynamics concurrently and in vivo to disentangle the neuronal and vascular components of FTY taking behavior. The studies proposed herein will use PAI to quantify neuronal ensembles and Fos-based neuroactivity, while simultaneously measuring hemodynamics and vascularization. Using transgenic Fos-LacZ rats we will study changes in PFC based on its known role in drug taking behavior and we will study females and males because of their unique patterns of drug taking. The proposed studies of this project address significant gaps, are highly innovative, and are forward looking. In short, the results of these studies will advance understanding of FTY and better integrate PAI in studies on the neurobiology of addiction.