Identification and interrogation of glial gene signatures in volitional opioid seeking

The National Institute on Drug Abuse awarded The Medical College of Wisconsin, Inc. $468,000 on September 15, 2026, under the Drug Use and Addiction Research Programs (CFDA 93.279) to identify and interrogate glial gene signatures in volitional opioid seeking.

The project addresses molecular adaptations underlying opioid addiction by characterizing transcriptional and epigenetic changes in glial populations—astrocytes, microglia, and oligodendrocytes—within mesolimbic reward regions. Prior research has relied on bulk tissue homogenates or neuron-centric sequencing that obscures glial-specific signatures; this award funds single-nuclei profiling and selective gene modulation approaches to isolate glial molecular signatures induced by persistent opioid use and interrogate their role in cellular and behavioral function. The work will develop tools for targeted CRISPR gene and epigenetic editing in glial populations to overcome limitations of existing cell-agnostic or neuron-focused approaches.

Performance occurs in Wauwatosa, Wisconsin, with a period of performance through July 31, 2031. The award is classified as a Project Grant, the standard assistance type for NIDA research funding supporting basic, clinical, translational, and implementation research in substance use prevention, diagnosis, and treatment.

Abstract

Drug addiction remains a pervasive public health crisis, affecting millions of individuals worldwide. Despite the enormous societal cost and continued increase in opioid-related overdoses, treatment options are limited. This is due in part to our incomplete understanding of which molecular adaptations initiated by opioid use are necessary for the transition to the addicted state. An inherent challenge in identifying and isolating the key transcriptional changes driving this process is the diverse cellular composition in mesolimbic reward regions, including glial populations like astrocytes, microglia, and oligodendrocytes. More recently, converging lines of research demonstrate that these glial populations play a central role in the transition to addiction. However, our ability to harness the therapeutic potential of glial-specific transcriptional and epigenetic manipulations in the context of addiction has been limited by a lack of detailed insight into which specific gene signatures are initiated during persistent drug taking, and the inability to selectively target these alterations in real time to interrogate their role in cellular and behavioral function. The majority of transcriptomic and chromatin profiling in the context of opioid misuse has relied on either bulk tissue homogenates or neuron-centric sequencing experiments. While informative, such approaches do not allow for in-depth examination of glial-specific molecular signatures induced by drugs of abuse. Another challenge in understanding the complex nature of drug-induced alternations in glia is the lack of available tools for selective modulation of gene targets in these populations. Traditional crispr gene and epigenetic editing approaches have focused primarily on cell-agnostic or neuronal modulation of individual gene targets. To overcome these hurdles, this proposal will utilize single-nuclei RNA-sequencing (snrna-SEQ) and the assay for transposase-accessible chromatin (snatac-SEQ) to define glial-specific gene signatures of contingent drug use in the mesolimbic reward circuitry of male and female rats. In addition to revealing novel and potentially SEX-specific therapeutic candidates, this information will be utilized to engineer new crispr/DCAS9-based epigenetic editing tools, which will allow for manipulation of drug-responsive genes in discrete glial populations. This approach will enable selective modification of individual or multiple gene targets simultaneously, effectively allowing US to test the requirement of complex glial gene programs in a volitional model of drug use. Collectively, the proposed experiments will be the first to define the exact nature and scope of glial-specific gene signatures following sustained drug experience, and to mechanistically link the requirement of these gene programs in reward neurocircuitry during drug self-administration.