Proteomic biosignatures of withdrawal from cocaine in rhesus monkeys

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DESCRIPTION (provided by applicant): Cocaine abuse and dependence in the United States continues to be a major public health concern yet significant obstacles remain for the appropriate diagnosis and treatment of individuals suffering from addictive disorders. Research efforts have focused primarily on the development and refinement of toxicological assays for detecting cocaine as a measure of recent cocaine use and on the identification of genetic markers indicative of a predisposition to cocaine abuse. While both approaches are useful in their own right, a continuing unmet medical need is the identification of peripheral biological markers that can assist with the objective diagnosis, identification of subsets of patients, and monitor progression and response to treatment. Moreover, biomarkers could also be used as indicators of neurobiological changes associated with chronic cocaine use. To this end, we will use our well developed track record in proteomics research relevant to cocaine abuse to identify and correlate plasma biomarkers with biochemical changes occurring in reward relevant brain regions during withdrawal from chronic cocaine self-administration in rhesus monkeys. These studies will leverage the scientific expertise of Drs. Porrino and Nader and the resources of their ongoing NIDA funded study (R01DA009085). In Aim 1, plasma samples will be collected longitudinally during a 100 day period of cocaine self- administration through a thirty day period of withdrawal. Samples will be analyzed using unbiased complimentary proteomic methods (2D-DIGE and iTRAQ/MDLC with MALDI ToF/ToF analysis) and appropriate validation methods. Multivariate statistical analysis approaches will be used to delineate a finite set of proteins with the greatest degree of discriminability between intake and withdrawal and between acute and chronic withdrawal. Studies in the Aim 2 will explore the cocaine induced dysregulation of NMDA and AMPA receptors and associated proteins in the ventral striatum at one and thirty days of withdrawal from cocaine. In addition, we will use a targeted proteomic approach to evaluate the effects of cocaine withdrawal on the NR1 subunit and associated complex in membrane fractions from the ventral striatum using iTRAQ /MDLC with MALDI ToF/ToF analysis. The expression of peripheral biomarkers identified in Aim 1 will be correlated with neurobiological changes identified in Aim 2. We anticipate these strategies will provide a preliminary biosignature of cocaine use/withdrawal and correlated neuronal dysregulation that ultimately can be used as a diagnostic and prognostic tool in the treatment of cocaine addiction. PUBLIC HEALTH RELEVANCE: A continuing need in addiction medicine is the identification of peripheral biological markers that are indicative of prior chronic drug use and are correlated with changes in the brain that mediate reward, craving and relapse. Using a rhesus monkey model of cocaine self-administration withdrawal, we propose to define a proteomic biosignature in plasma that is correlated with neurobiological changes occurring in response to cocaine withdrawal. The proposed studies are intended to delineate a preliminary set of peripheral biomarkers that can be further evaluated in the rhesus monkey model and in human behavioral laboratory studies before implementing as potential diagnostic and prognostic tool at the clinic.