Examination of epigenetic spatial architecture in the CNS as a method to understand cocaine relapse in ecoHIV infected mice

Drexel University, Philadelphia PA

Investigators

Abstract

This proposal seeks to develop a new imaging pipeline that will examine tissue level and nuclear level spatial architecture of histone dopaminylation in the CNS of ecoHIV infected mice allowed to self administer cocaine. To achieve this goal we will develop a new imaging pipeline that that collects large numbers of images (>15,000 per animal and brain region) and analyzes them using a novel AI-powered, machine learning approach. Substance use disorders (SUD) are a chronic disease of the CNS that are characterized by compulsive craving that persists even after substance use ceases. The development of SUD is associated with a transition in brain physiology that maintains drug seeking and taking. Epigenetics, the change in gene expression without change to DNA sequence, and the underlying mechanisms of histone modification, transcription factor recruitment and DNA packaging, is involved in an array of neurodegenerative diseases, including control of HIV transcription. Furthermore, there is evidence that substance use drives changes in chromatin structure and therefore may alter gene expression, and that these changes may play a role in relapse to drug use. Recent studies have shown that dopamine can modify histones of cells in the CNS and that dopaminylation drives cocaine seeking behavior in rodents. Techniques that can connect the available powerful single cell molecular approaches and gross examination of the CNS by both traditional histology and modern non-invasive imaging for the study of HIV and substance use have not been used extensively. We propose to address this technical shortcoming by combining our strengths in epigenetics, high resolution imaging of the CNS, computational biology and animal behavior. We will query sub-nuclear and tissue region architecture of epigenetic modifications, including the newly discovered dopaminylation of histone H3 (H3Q5dop), analyze the resulting data using a machine learning based pipeline, and then correlate this architecture to behavioral outcomes as they relate to drug seeking behavior. In addition to the creation and testing of new technologies, we will address the hypothesis that altered dopaminylation of histones in astrocytes is the mechanism by which HIV infection enhances sensitivity to cocaine’s neurobehavioral properties. We develop our technology in the R61 exploratory phase (Aim 1: Imaging of H3Q5dop and other epigenetic marks in nuclei isolated from mice self-administering cocaine, Aim 2: Assess applicability of tissue clearing protocols to whole-tissue imaging of histone modification, Aim 3: Determine applicability of NUCLEO-M and tissue clearing microscopy to existing tissue bank samples) and fully test our behavioral hypothesis in the R33 application phase (Aim 4: Assess the independent and interactive effects of cocaine exposure on nuclear architecture in a model of HIV infection, Aim 5: Determine the contribution of dopaminylation to the regulation of cocaine seeking in a mouse model of HIV infection)