Smith Laboratory

High-Throughput Addiction NeuroDiscovery Lab

Dr. Alexander Smith (Alex) received his PhD in Neuroscience in 2015 at MUSC, where he was mentored by Dr. Peter Kalivas. Alex then went to Mount Sinai in NYC and completed postdoctoral training in the lab of Dr. Paul Kenny. He then came back to MUSC to join the faculty in December of 2021.

Alex’s graduate work in the Kalivas Lab primarily used rat models of cued reinstatement, and protein biochemistry to examine the contributions of two extracellular matrix remodeling enzymes, MMP2 and MMP9, to synaptic plasticity underlying cocaine relapse.

During his postdoctoral training, Alex primarily used mouse models, and shifted to a much more systems-oriented approach, using opto- and chemo-genetics to examine the role of specific neural circuits to addictive-like behaviors. While in the Kenny Lab, Alex also became an expert in brain clearing and using light-sheet microscopy to examine protein expression (e.g. c-Fos), or projection mapping/quantification, in the intact brain. Alex’s postdoctoral work also shifted from protein-level biochemistry to RNA analysis, using qPCR, RNAscope, and single-nuclei sequencing.

Alex’s independent lab will use a combination of these techniques, using high-throughput methods like brain clearing and single-nuclei sequencing to identify novel neuroadaptations that accompany relapse, and using protein-level biochemistry and small-molecule pharmacology to examine the precise mechanisms of these adaptations. The ultimate goal for the lab is to identify novel targets that can be targeted to reduce relapse in clinical populations.

Research:
Identification of Novel Circuits & Molecules Underlying Cue-Induced Reinstatement of Oxycodone Seeking
Alex is currently funded by an R00 from NIDA, having completed the K99 phase of the award at Mount Sinai. During the K99 phase of this project, Alex trained mice to self-administer sucrose, oxycodone, or saline, and used whole-brain c-Fos mapping to identify novel regions that are activated by cue-induced reinstatement of oxycodone, but not sucrose seeking. This revealed several highly novel regions that show c-Fos expression that is tightly correlated with reinstatement behavior. In the R00 phase of this award, Alex’s lab will use single-nuclei sequencing of these regions to identify individual transcripts that are regulated by opioid-conditioned cues, and then will test the efficacy of pharmacologically manipulating target genes in reducing reinstatement behavior.

Project Summary
The US is in the midst of an opioid abuse and overdose epidemic. Oxycodone is one of the most prescribed analgesics, is the first opioid many people experience, and has physiochemical properties that allow it to accumulate in the brain at rates higher than other opioids, perhaps explaining its considerable abuse potential. Here, I seek to perform high-throughput experiments to generate brain-wide data on the cellular and molecular mechanisms of cue-induced reinstatement to oxycodone seeking. Specifically, I propose to use FosCreER mice to fluorescently `tag' neuronal ensembles activated by cue-induced reinstatement. I will then use cutting-edge transcriptomics to identify relapse-related genes in these cellular ensembles that drive reinstatement. I will then prioritize, and test, whether these genes may serve substrates for the development of novel medications to prevent relapse using a ”circuit therapeutic” approach. In aim 1, iDISCO+, a lipid clearing method, will produce brain-wide data on regions activated by relapse. I will then use ClearMap, a published Python package, to conduct high-throughput detection of activated neurons and registration of coordinates onto the Allen Brain Atlas. I will then rigorously examine this large data set, and test whether reinstatement-responsive cell ensembles in prioritized structures contribute to relapse behavior. In aim 2, I will focus on cellular populations in brain regions shown to be required for relapse-related behavior and will again tag neurons activated by reinstatement in these sites. Tissue will be dissected, and fluorescence activated cell sorting will be used to isolate these activated neurons for trancriptomic profiling via RNA-Seq. Together, these two aims will yield large data sets directly related to the neurocircuitry and molecular biology of reinstatement of oxycodone seeking. I will once again rigorously analyze these data sets, with strict adherence to pre-established criteria, to prioritize reinstatement-responsive genes most likely to represent efficacious targets for development of novel pharmacotherapeutics. Following completion of the training phase, in aim 3 I will extend these findings to both rat and mouse models of self-administration and will validate that these transcriptomic adaptations occur across species, and that they are detected as changes in functional proteins. Once again, I will rigorously prioritize these targets for translational potential. In aim 4 I will use pharmacological agents that modulate prioritized protein targets to determine whether they can block cue-induced reinstatement of oxycodone seeking, focusing on compounds that may be able to quickly move into clinical settings. The training added in this proposal will allow me to emerge as an exceptionally well-rounded independent investigator. During my independent career I will perform translational research to develop novel circuit-based therapeutics for prevention of relapse.

Evaluating potential therapeutic effect of psychedelics in substance use disorders
A second project in the lab is examining whether psychedelics show promise for treatment of substance use disorders. Psychedelics (e.g. psilocybin) have shown great promise for treatment of neuropsychiatric disorders like anxiety and depression. While anecdotal evidence suggests that psychedelics may be helpful in human subjects attempting to abstain from drug use, there is a need for both clinical and preclinical research on the efficacy and mechanisms for this effect. We are employing a novel ‘stress-cue-induced reinstatement’ paradigm in which mice are subjected to stressful experiences in the presence of a conditioned stimulus, and then are allowed to self-administer heroin. Following daily heroin intake and abstinence, the stimulus previously associated with a stressful experience robustly induces relapse in our animal model. Experiments are underway to determine whether psilocybin or other psychedelics are able to reduce behavioral responses to these stress-associated stimuli.

Team:
Alex Smith, Ph.D.
Assistant Professor

Scott Mitchell, Ph.D.
Postdoctoral fellow

Megan Francis, B.S.
Graduate Student

Anna Tsyrulnikov, B.S.
Graduate Student

James Welsh, M.S.
Research Assistant

Peter Kayastha, B.S.
Research Assistant


Smith Laboratory Recent Publications (2020-current):
Smith ACW, Ghoshal S, Centanni SW, Khan S, Heyer MP, Corona A, Wills L, Andraka E, Lei Y, O’Connor RM, Caligiuri SPB, Khan S, Beaumont K, Sebra RP, Kieffer BL, Winder DG, Ishikawa M, Kenny PJ. (In Press) A master regulator of opioid reward in ventral prefrontal cortex. Science. doi: 10.1126/science.adn0886.

Centanni SW, Smith ACW (2023) PiRATeMC: A highly flexible, scalable, and affordable system for obtaining high quality video recordings for behavioral neuroscience. Addiction Neuroscience. 8(1):100108 doi: 10.1016/j.addicn.2023.100108. PMID: 37691741 PMCID: PMC10487299.

Caligiuri SPB, Howe WM, Wills L, Smith ACW, Lei Y, Bali P, Heyer MP, Moen JK, Ables JL, Elayouby KS, Williams M, Fillinger C, Oketokoun Z, Lehmann VE, DiFeliceantonio AG, Johnson PM, Beaumont K, Sebra R, Ibanez-Tallon I, Kenny PJ (2022) Hedgehog-interacting protein acts in the habenula to regulate nicotine intake. Proc Nat Acad Sciences. 119(46):e2209870119. PMID: 36346845.

Smith ACW, Jonkman S, Difeliceantonio AG, O'Connor RM, Ghoshal S, Romano MF, Everitt BJ, Kenny PJ. Opposing roles for striatonigral and striatopallidal neurons in dorsolateral striatum in consolidating new instrumental actions. Nat Commun. 2021 Aug 25;12(1):5121. doi: 10.1038/s41467-021-25460-3. PubMed PMID: 34433818; PubMed Central PMCID: PMC8387469.

Roberts-Wolfe DJ, Heinsbroek JA, Spencer SM, Bobadilla AC, Smith ACW, Gipson CD, Kalivas PW. Transient synaptic potentiation in nucleus accumbens shell during refraining from cocaine seeking. Addict Biol. 2020 May;25(3):e12759. doi: 10.1111/adb.12759. Epub 2019 May 6. PubMed PMID: 31062493; PubMed Central PMCID: PMC7371007.

Lepack AE, Werner CT, Stewart AF, Fulton SL, Zhong P, Farrelly LA, Smith ACW, Ramakrishnan A, Lyu Y, Bastle RM, Martin JA, Mitra S, O'Connor RM, Wang ZJ, Molina H, Turecki G, Shen L, Yan Z, Calipari ES, Dietz DM, Kenny PJ, Maze I. Dopaminylation of histone H3 in ventral tegmental area regulates cocaine seeking. Science. 2020 Apr 10;368(6487):197-201. doi: 10.1126/science.aaw8806. PubMed PMID: 32273471; PubMed Central PMCID: PMC7228137.

Buchta WC, Moutal A, Hines B, Garcia-Keller C, Smith ACW, Kalivas P, Khanna R, Riegel AC. Dynamic CRMP2 Regulation of CaV2.2 in the Prefrontal Cortex Contributes to the Reinstatement of Cocaine Seeking. Mol Neurobiol. 2020 Jan;57(1):346-357. doi: 10.1007/s12035-019-01711-9. Epub 2019 Jul 29. PubMed PMID: 31359322; PubMed Central PMCID: PMC6980501.

For more information on the work we do in our lab, please visit  https://www.smithlabmusc.com/