Biology subjects

Crist, R. C.

Publications and source records attributed to Crist, R. C..

11 recordsLinked to original sources

bioRxiv2026

Volitional cocaine taking engages distinct medium spiny neuron and astrocyte transcriptional programs in the rat nucleus accumbens

Cocaine use disorder (CUD) remains a major public health concern with no FDA-approved pharmacotherapy, underscoring the need to define the cellular and molecular adaptations produced by voluntary cocaine taking. The nucleus accumbens (NAc) is a key substrate for cocaine reinforcement and drug-seeking behavior, but interpretation of the functional role of its cellular heterogeneity in these behaviors is limited by past bulk transcriptomic studies. Here, we used single-nucleus RNA sequencing to profile the NAc of male and female rats that self-administered intravenous cocaine for 10 consecutive days versus yoked saline controls. After quality control, we analyzed 36,766 nuclei spanning major neuronal, glial, and vascular cell populations. Pseudobulk differential-expression analyses identified 478 cocaine-associated cell type-specific transcriptional changes that were concentrated in discrete medium spiny neuron (MSN) subclasses and astrocytes. D1 Ebf1+ MSNs showed the largest transcriptomic response, accounting for [~]40% of all differential-expression events, followed by D2 Stk32a+ MSNs, astrocytes, and D1 Ppm1e+ MSNs. These responses were largely cell type-specific, indicating that cocaine self-administration engages multiple molecular programs rather than a uniform accumbens-wide transcriptional signature. Immediate-early gene module-score analyses further revealed cocaine-associated activation states in select neuronal and non-neuronal cell populations, including D1 Ebf1+ MSNs, Drd3+ neurons, Sst+ interneurons, astrocytes, and oligodendrocytes. Gene-set, pathway, and upstream-regulator analyses nominated synaptic organization, axon guidance, RAS/MAPK signaling, NMDA receptor-associated signaling, and CREB-related transcriptional regulation as candidate mechanisms of cocaine-evoked plasticity. Together, these data provide a cell type-resolved resource for understanding how voluntary cocaine taking alters the rat NAc transcriptome and identifies discrete neuronal and glial cell populations for future mechanistic studies using preclinical CUD models.

neuroscience↗

bioRxiv2026

Early resource scarcity drives persistent transcriptional changes and vascular remodeling in the female prefrontal cortex

Early childhood poverty is an environmental risk factor for psychiatric and neurodegenerative disorders, yet the cellular mechanisms by which resource scarcity produces persistent brain vulnerability remain poorly understood. The medial prefrontal cortex (mPFC), which regulates executive function and motivated behavior, is sensitive to early environmental conditions. To identify mechanisms linking early resource scarcity to lasting mPFC dysfunction, we used the rat limited bedding and nesting (LBN) model, which recapitulates key features of poverty. Prior work shows LBN disrupts mPFC-mediated behaviors in adulthood, often in a sex-specific manner. Here, we used single-nucleus RNA sequencing (snRNAseq) to identify sex- and cell-type-specific transcriptional alterations in the adult mPFC following brief postnatal LBN exposure or control housing. LBN induced more differentially expressed genes (DEGs) across multiple pyramidal neuron clusters in females than in males. Unexpectedly, the largest transcriptional changes due to LBN occurred in vascular cells in females, whereas male vascular cells exhibited no DEGs. These female-specific vascular genes were enriched for alterations of transcriptional programs regulating angiogenesis and endothelial structure. This molecular profile was orthogonally validated with 3D vascular reconstruction, revealing LBN reduced vascular coverage in the adult female mPFC, driven by decreased vessel volume and shortened vessel length, while males were unaffected. Reduced vascular coverage may constrain metabolic support to this region. The postnatal period is a critical window for vascular maturation, and, taken together, these findings identify persistent, female-specific vascular alterations as a novel and previously unrecognized mechanism through which early resource scarcity may persistently affect brain function and vulnerability.

neuroscience↗

bioRxiv2025

Convergent state-control of endogenous opioid analgesia

Pain is a dynamic and nonlinear experience shaped by injury and contextual factors, including expectations of future pain or relief1. While {micro} opioid receptors are central to the analgesic effects of opioid drugs, the endogenous opioid neurocircuitry underlying pain and placebo analgesia remains poorly understood. The ventrolateral column of the posterior periaqueductal gray is a critical hub for nociception and endogenous analgesia mediated by opioid signaling2. However, significant gaps remain in understanding the cell-type identities, the sub-second neural dynamics involved in pain modulation, the role of endogenous peptide neuromodulators, and the contextual factors influencing these processes. Using spatial mapping with single-nuclei RNA sequencing of pain-active neurons projecting to distinct long-range brain targets, alongside cell type-specific and activity-dependent genetic tools for in vivo optical recordings and modulation of neural activity and opioid peptide release, we identified a functional dichotomy in the ventrolateral periaqueductal gray. Neurons expressing {micro} opioid receptors encode active nociceptive states, whereas enkephalin-releasing neurons drive pain relief during recovery from injury, in response to learned fear predictions, and during placebo analgesia. Finally, by leveraging the functional effects of placebo analgesia, we used direct optogenetic activation of vlPAG enkephalin neurons to drive opioid peptide release, resulting in a robust reduction in pain. These findings show that diverse need states converge on a shared midbrain circuit that releases endogenous opioids with high spatiotemporal precision to suppress nociceptive activity and promote analgesia.

neuroscience↗

bioRxiv2024

An endogenous GLP-1 circuit engages VTA GABA neurons to regulate mesolimbic dopamine neurons and attenuate cocaine seeking

Recent studies show that systemic administration of a glucagon-like peptide-1 receptor (GLP-1R) agonist is sufficient to attenuate the reinstatement of cocaine-seeking behavior, an animal model of relapse. However, the neural mechanisms mediating these effects and the role of endogenous central GLP-1 signaling in cocaine seeking remain unknown. Here, we show that voluntary cocaine taking decreased plasma GLP-1 levels in rats and that chemogenetic activation of GLP-1-producing neurons in the nucleus tractus solitarius (NTS) that project to the ventral tegmental area (VTA) decreased cocaine reinstatement. Single nuclei transcriptomics and FISH studies revealed GLP-1Rs are expressed primarily on GABA neurons in the VTA. Using in vivo fiber photometry, we found that the efficacy of a systemic GLP-1R agonist to attenuate cocaine seeking was associated with increased activity of VTA GABA neurons and decreased activity of VTA dopamine neurons. Together, these findings suggest that targeting central GLP-1 circuits may be an effective strategy toward reducing cocaine relapse and highlight a novel functional role of GABAergic GLP-1R-expressing midbrain neurons in drug seeking.

neuroscience↗

bioRxiv2024

A single-nucleus transcriptomic atlas of medium spiny neurons in the rat nucleus accumbens

Neural processing of rewarding stimuli involves several distinct regions, including the nucleus accumbens (NAc). The majority of NAc neurons are GABAergic projection neurons known as medium spiny neurons (MSNs). MSNs are broadly defined by dopamine receptor expression, but evidence suggests that a wider array of subtypes exist. To study MSN heterogeneity, we analyzed single-nucleus RNA sequencing data from the largest available rat NAc dataset. Analysis of 48,040 NAc MSN nuclei identified major populations belonging to the striosome and matrix compartments. Integration with mouse and human data indicated consistency across species and disease-relevance scoring using genome-wide association study results revealed potentially differential roles for MSN populations in substance use disorders. Additional high-resolution clustering identified 34 transcriptomically distinct subtypes of MSNs definable by a limited number of marker genes. Together, these data demonstrate the diversity of MSNs in the NAc and provide a basis for more targeted genetic manipulation of specific populations.

genetics↗

bioRxiv2024

Mimicking opioid analgesia in cortical pain circuits

The anterior cingulate cortex is a key brain region involved in the affective and motivational dimensions of pain, yet how opioid analgesics modulate this cortical circuit remains unclear. Uncovering how opioids alter nociceptive neural dynamics to produce pain relief is essential for developing safer and more targeted treatments for chronic pain. Here we show that a population of cingulate neurons encodes spontaneous pain-related behaviors and is selectively modulated by morphine. Using deep-learning behavioral analyses combined with longitudinal neural recordings in mice, we identified a persistent shift in cortical activity patterns following nerve injury that reflects the emergence of an unpleasant, affective chronic pain state. Morphine reversed these neuropathic neural dynamics and reduced affective-motivational behaviors without altering sensory detection or reflexive responses, mirroring how opioids alleviate pain unpleasantness in humans. Leveraging these findings, we built a biologically inspired gene therapy that targets opioid-sensitive neurons in the cingulate using a synthetic mu-opioid receptor promoter to drive chemogenetic inhibition. This opioid-mimetic gene therapy recapitulated the analgesic effects of morphine during chronic neuropathic pain, thereby offering a new strategy for precision pain management targeting a key nociceptive cortical opioid circuit with safe, on-demand analgesia. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=40 SRC="FIGDIR/small/591113v2_ufig1.gif" ALT="Figure 1"> View larger version (28K): org.highwire.dtl.DTLVardef@d294c0org.highwire.dtl.DTLVardef@123d4f4org.highwire.dtl.DTLVardef@1720deborg.highwire.dtl.DTLVardef@efc632_HPS_FORMAT_FIGEXP M_FIG C_FIG

neuroscience↗

bioRxiv2024

A nociceptive amygdala-striatal pathway for chronic pain aversion

The basolateral amygdala (BLA) is essential for assigning positive or negative valence to sensory stimuli. Noxious stimuli that cause pain are encoded by an ensemble of nociceptive BLA projection neurons (BLAnoci ensemble). However, the role of the BLAnoci ensemble in mediating behavior changes and the molecular signatures and downstream targets distinguishing this ensemble remain poorly understood. Here, we show that the same BLAnoci ensemble neurons are required for both acute and chronic neuropathic pain behavior. Using single nucleus RNA-sequencing, we characterized the effect of acute and chronic pain on the BLA and identified enrichment for genes with known functions in axonal and synaptic organization and pain perception. We thus examined the brain-wide targets of the BLAnoci ensemble and uncovered a previously undescribed nociceptive hotspot of the nucleus accumbens shell (NAcSh) that mirrors the stability and specificity of the BLAnoci ensemble and is recruited in chronic pain. Notably, BLAnoci ensemble axons transmit acute and neuropathic nociceptive information to the NAcSh, highlighting this nociceptive amygdala-striatal circuit as a unique pathway for affective-motivational responses across pain states.

neuroscience↗

bioRxiv2023

Ventral hippocampus neurons encode meal-related memory

The ability to encode and retrieve meal-related information is critical to efficiently guide energy acquisition and consumption, yet the underlying neural processes remain elusive. Here we reveal that ventral hippocampus (HPCv) neuronal activity dynamically elevates during meal consumption and this response is highly predictive of subsequent performance in a foraging-related spatial memory task. Targeted recombination-mediated ablation of HPCv meal-responsive neurons impairs foraging-related spatial memory without influencing food motivation, anxiety-like behavior, or escape-mediated spatial memory. These HPCv meal-responsive neurons project to the lateral hypothalamic area (LHA) and single-nucleus RNA sequencing and in situ hybridization analyses indicate they are enriched in serotonin 2a receptors (5HT2aR). Either chemogenetic silencing of HPCv-to-LHA projections or intra-HPCv 5HT2aR antagonist yielded foraging-related spatial memory deficits, as well as alterations in caloric intake and the temporal sequence of spontaneous meal consumption. Collective results identify a population of HPCv neurons that dynamically respond to eating to encode meal-related memories.

neuroscience↗

bioRxiv2020

Single-nuclei transcriptomics of schizophrenia prefrontal cortex primarily implicates neuronal subtypes

Transcriptomic studies of bulk neural tissue homogenates from persons with schizophrenia and controls have identified differentially expressed genes in multiple brain regions. However, the brains heterogeneous nature prevents identification of relevant cell types. This study analyzed single-nuclei transcriptomics of ~275,000 nuclei from frozen human postmortem dorsolateral prefrontal cortex samples from males with schizophrenia (n = 12) and controls (n = 14). 4,766 differential expression events were identified in 2,994 unique genes in 16 of 20 transcriptomically-distinct cell populations. ~96% of differentially expressed genes occurred in five neuronal cell types, and differentially expressed genes were enriched for genes associated with schizophrenia and bipolar GWAS loci. Downstream analyses identified cluster-specific enriched gene ontologies, KEGG pathways, and canonical pathways. Additionally, microRNAs and transcription factors with overrepresented neuronal cell type-specific targets were identified. These results expand our knowledge of disrupted gene expression in specific cell types and permit new insight into the pathophysiology of schizophrenia.

neuroscience↗

bioRxiv2019

Restriction Enzyme Based Enriched L1Hs sequencing (REBELseq)

Long interspersed element-1 retrotransposons (LINE-1 or L1) are ~6 kb mobile DNA elements implicated in the origins of many Mendelian and complex diseases. The actively retrotransposing L1s are mostly limited to the L1 human specific Ta subfamily. In this manuscript, we present REBELseq as a method for the construction of differentially amplified next-generation sequencing libraries and bioinformatic identification of Ta subfamily long interspersed element-1 human specific elements. REBELseq was performed on DNA isolated from NeuN+ neuronal nuclei from postmortem brain samples of 177 individuals and empirically-driven bioinformatic and experimental cutoffs were established. REBELseq reliably identified both known and novel Ta subfamily L1 insertions distributed throughout the genome. Differences in the proportion of individuals possessing a given reference or non-reference retrotransposon insertion were identified. We conclude that REBELseq is an unbiased, whole genome approach to the amplification and detection of Ta subfamily L1 retrotransposons.

genetics↗

bioRxiv2018

Genome-wide association study meta-analysis of the Alcohol Use Disorder Identification Test (AUDIT) in two population-based cohorts (N=141,958)

Alcohol use disorders (AUD) are common conditions that have enormous social and economic consequences. We obtained quantitative measures using the Alcohol Use Disorder Identification Test (AUDIT) from two population-based cohorts of European ancestry: UK Biobank (UKB; N=121,604) and 23andMe (N=20,328) and performed a genome-wide association study (GWAS) meta-analysis. We also performed GWAS for AUDIT items 1-3, which focus on consumption (AUDIT-C), and for items 4-10, which focus on the problematic consequences of drinking (AUDIT-P). The GWAS meta-analysis of AUDIT total score identified 10 associated risk loci. Novel associations localized to genes including JCAD and SLC39A13; we also replicated previously identified signals in the genes ADH1B, ADH1C, KLB, and GCKR. The dimensions of AUDIT showed positive genetic correlations with alcohol consumption (rg=0.76-0.92) and Diagnostic and Statistical Manual of Mental Disorders (DSM-IV) alcohol dependence (rg=0.33-0.63). AUDIT-P and AUDIT-C showed significantly different patterns of association across a number of traits, including psychiatric disorders. AUDIT-P was positively genetically correlated with schizophrenia (rg=0.22, p=3.0x10-10), major depressive disorder (rg=0.26, p=5.6x10-3), and attention-deficit/hyperactivity disorder (ADHD; rg=0.23, p=1.1x10-5), whereas AUDIT-C was negatively genetically correlated with major depressive disorder (rg=-0.24, p=3.7x10-3) and ADHD (rg=-0.10, p=1.8x10-2). We also used the AUDIT data in the UKB to identify thresholds for dichotomizing AUDIT total score that optimize genetic correlations with DSM-IV alcohol dependence. Coding individuals with AUDIT total score of [≤]4 as controls and [≥]12 as cases produced a high genetic correlation with DSM-IV alcohol dependence (rg=0.82, p=3.2x10-6) while retaining most subjects. We conclude that AUDIT scores ascertained in population-based cohorts can be used to explore the genetic basis of both alcohol consumption and AUD.

genetics↗