Biology subjects

Choi, E. Y.

Publications and source records attributed to Choi, E. Y..

11 recordsLinked to original sources

bioRxiv2025

Aberrant recursive splicing in a human disease locus

Recursive splice sites are rare motifs postulated to facilitate splicing across massive introns and shape isoform diversity, especially for long, brain-expressed genes. The necessity of this unique mechanism remains unsubstantiated, as does the role of recursive splicing (RS) in human disease. From analyses of rare copy number variants (CNVs) from almost one million individuals, we previously identified large, heterozygous deletions eliminating an RS site (RS1) in the first intron of CADM2 that conferred substantial risk for attention deficit hyperactivity disorder (ADHD) and other neurobehavioral traits. CADM2 encodes a neuronally expressed cell adhesion molecule that has repeatedly been associated with ADHD and numerous similar traits. To explore the molecular impact of RS ablation in CADM2, we used CRISPR to model patient deletions and to target a smaller region ([~]500 base pairs) containing RS1 in both human induced neurons (iNs) and rats. Transcriptome analyses in unedited iNs provided a catalog of CADM2 transcripts, including novel transcripts that retained RS exons. Intriguingly, ablating RS1 altered the gradient of RNA abundance across the first intron of CADM2, decreased the level of CADM2 expression, and impacted transcript usage. Decreased CADM2 expression was reflected in reduced exon usage downstream of the RS1 site and global alteration to genes involved in neuronal processes including synapse and axon development. Given the scale of our analyses and the widespread association of CADM2 with neurobehavioral traits, we sought to validate these findings using in vivo models and found that rodent models harboring Cadm2 RS1 deletions exhibited significant changes in relevant behaviors and functional brain connectivity. In summary, our analyses demonstrate a functional role for RS as a noncoding regulatory mechanism in a gene associated with a spectrum of neuropsychiatric and behavioral traits. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=140 SRC="FIGDIR/small/666599v1_ufig1.gif" ALT="Figure 1"> View larger version (44K): org.highwire.dtl.DTLVardef@171156borg.highwire.dtl.DTLVardef@13553baorg.highwire.dtl.DTLVardef@bee7forg.highwire.dtl.DTLVardef@156f19e_HPS_FORMAT_FIGEXP M_FIG Graphical Abstract C_FIG

genomics↗

bioRxiv2025

Dopamine receptor 1 specific CRISPRa mice exhibit disrupted behaviors and striatal baseline cellular activity

The two main cell types in the striatum, dopamine receptor 1 and adenosine receptor 2a spiny projection neurons (D1-SPNs and A2A-SPNs), have distinct roles in regulating motor- and reward-related behaviors. Cre-selective CRISPR-dCas9 systems allow for cell-type specific, epigenomic-based manipulation of gene expression with gene-specific single guide RNAs (sgRNAs) and have potential to elucidate molecular mechanisms underlying striatal subtype mediated behaviors. Conditional transgenic Rosa26:LSL-dCas9-p300 mice were recently generated to allow for robust expression of dCas9-p300 expression with Cre-driven cell-type specificity. This system utilizes p300, a histone acetyltransferase which regulates gene expression by unwinding chromatin and making that region of the genome more accessible for transcription. Rosa26-LSL-dCas9-p300 mice were paired with Drd1-Cre and Ador2a-Cre mice to generate Drd1-Cre:dCas9-p300 and Ador2a-Cre:dCas9-p300 mouse lines and underwent behavioral phenotyping when sgRNAs were not present. Both Drd1-Cre:dCas9-p300 and Ador2a-Cre:dCas9-p300 have cell-type specific expression of spCas9 mRNA. Baseline behavioral assessments revealed that, under a sgRNA absent nontargeted state, Drd1-Cre:dCas9-p300 mice display repetitive spinning behavior, hyperlocomotion and enhanced acquisition of reward learning in comparison to all genotypic littermates. In contrast, Ador2a-Cre:dCas9-p300 do not exhibit any changes in behavior in comparison to their littermates. Electrophysiological recordings of dorsal striatum D1-SPNs revealed that Drd1-Cre:dCas9-p300 mice have increased input resistance and increased spontaneous excitatory postsynaptic current amplitude, together suggesting greater excitatory drive of D1-SPNs. Overall, these data demonstrate the necessity to validate CRISPR-dCas9 lines for research investigations. Additionally, the Drd1-Cre:dCas9-p300 line has the potential to be used to study underlying mechanisms of stereotypy and reward-learning. Significance StatementUsing CRISPR-based tools to identify cell-type specific epigenomic and transcriptional mechanisms in disease and behavior has high utility for the neuroscience field. Previous limitations related to implementation of CRISPR-editing systems in mice were thought to be overcome by the generation of transgenic mouse lines, including a novel Cre-dependent dCas9-p300 mouse line. Our data shows however that Drd1-Cre:dCas9-p300 mice, generated from breeding Drd1-Cre mice with the dCas9-p300 mice, have cellular and behavioral disruptions under a nontargeted sgRNA absent state. Overall, these data suggest caution in employing CRISPR-dCas9 systems, particularly transgenic mouse lines, for research investigations.

neuroscience↗

bioRxiv2024

A mosaic of whole-body representations in human motor cortex

Understanding how the body is represented in motor cortex is key to understanding how the brain controls movement. The precentral gyrus (PCG) has long been thought to contain largely distinct regions for the arm, leg and face (represented by the "motor homunculus"). However, mounting evidence has begun to reveal a more intermixed, interrelated and broadly tuned motor map. Here, we revisit the motor homunculus using microelectrode array recordings from 20 arrays that broadly sample PCG across 8 individuals, creating a comprehensive map of human motor cortex at single neuron resolution. We found whole-body representations throughout all sampled points of PCG, contradicting traditional leg/arm/face boundaries. We also found two speech-preferential areas with a broadly tuned, orofacial-dominant area in between them, previously unaccounted for by the homunculus. Throughout PCG, movement representations of the four limbs were interlinked, with homologous movements of different limbs (e.g., toe curl and hand close) having correlated representations. Our findings indicate that, while the classic homunculus aligns with each areas preferred body region at a coarse level, at a finer scale, PCG may be better described as a mosaic of functional zones, each with its own whole-body representation.

neuroscience↗

bioRxiv2024

Circulating extracellular microRNAs in the blood promote sociability in mice

Extracellular vesicles (EVs) are cell-derived small membrane vesicles and circulate throughout the body, but the impact of circulating EVs on brain function and behavior remains elusive. Here, we report that wild-type (WT) mouse blood, particularly EVs, increases sociability in socially impaired immunodeficient Rag1-/- mice, mimicking the effects of WT T cell transfer. These EVs localized to neurons and regulated PKC{varepsilon} expression, GABAA receptor synaptic localization, and inhibitory postsynaptic signaling in prefrontal cortex (PFC) pyramidal neurons. Injection of Rag1-/- EVs supplemented with miR-23a-3p and miR-103-3p enhanced synaptic function and sociability in Rag1-/- mice. T cells secreted miR-23a-3p via EVs, and Mir23a-/- T cells failed to increase sociability. Similar beneficial effects of WT blood EVs were observed in additional mouse models with sociability deficits, Cntnap2-/- and Shank3-/- mice. These findings uncover a previously unrecognized role of EV miRNAs in mediating immune modulation of synaptic function and social behavior, revealing a novel molecular pathway for immune-neuron communication.

neuroscience↗

bioRxiv2023

A high-performance speech neuroprosthesis

Speech brain-computer interfaces (BCIs) have the potential to restore rapid communication to people with paralysis by decoding neural activity evoked by attempted speaking movements into text1,2 or sound3,4. Early demonstrations, while promising, have not yet achieved accuracies high enough for communication of unconstrainted sentences from a large vocabulary1-7. Here, we demonstrate the first speech-to-text BCI that records spiking activity from intracortical microelectrode arrays. Enabled by these high-resolution recordings, our study participant, who can no longer speak intelligibly due amyotrophic lateral sclerosis (ALS), achieved a 9.1% word error rate on a 50 word vocabulary (2.7 times fewer errors than the prior state of the art speech BCI2) and a 23.8% word error rate on a 125,000 word vocabulary (the first successful demonstration of large-vocabulary decoding). Our BCI decoded speech at 62 words per minute, which is 3.4 times faster than the prior record for any kind of BCI8 and begins to approach the speed of natural conversation (160 words per minute9). Finally, we highlight two aspects of the neural code for speech that are encouraging for speech BCIs: spatially intermixed tuning to speech articulators that makes accurate decoding possible from only a small region of cortex, and a detailed articulatory representation of phonemes that persists years after paralysis. These results show a feasible path forward for using intracortical speech BCIs to restore rapid communication to people with paralysis who can no longer speak.

neuroscience↗

bioRxiv2022

Inducible CRISPR epigenome systems mimic cocaine induced bidirectional regulation of Nab2 and Egr3

Substance use disorder is a debilitating chronic disease and a leading cause of disability around the world. The nucleus accumbens (NAc) is a major brain hub that mediates reward behavior. Studies demonstrate exposure to cocaine is associated with molecular and functional imbalance in two NAc medium spiny neuron subtypes (MSNs), dopamine receptor 1 and 2 enriched D1-MSNs and D2-MSNs. Our previous reports showed that repeated cocaine exposure induced transcription factor early growth response 3 (Egr3) mRNA in NAc D1-MSNs, while reducing it in D2-MSNs. Here, we report our findings of repeated cocaine exposure inducing cell subtype specific bidirectional expression of the Egr3 corepressor NGFI-A-binding protein 2 (Nab2). Using CRISPR activation and interference (CRISPRa and CRISPRi) tools combined with Nab2 or Egr3 targeted sgRNAs, we mimicked these bidirectional changes in Neuro2a cells. Furthermore, we investigated D1-MSN and D2-MSN subtype specific expressional changes of histone lysine demethylases Kdm1a, Kdm6a and Kdm5c in NAc after repeated cocaine exposure. Since Kdm1a showed bidirectional expression patterns in D1-MSNs and D2-MSNs, like Egr3, we developed a light inducible Opto-CRISPR-KDM1a system. We were able to downregulate Egr3 and Nab2 transcripts and cause bidirectional expression changes in D1-MSNs and D2-MSNs similar to cocaine exposure in Neuro2A cells. In contrast, our Opto-CRISPR-p300 activation system induced the Egr3 and Nab2 transcripts and caused bidirectional transcription regulations in D1-MSNs and D2-MSNs. Our study sheds light on the expression patterns of Nab2 and Egr3 in specific NAc MSN subtypes in cocaine action and uses CRISPR tools to further mimic these expression patterns.

neuroscience↗

bioRxiv2021

Transcriptome profiling of the ventral pallidum reveals a role for pallido-thalamic neurons in cocaine reward

Psychostimulant exposure alters the activity of ventral pallidum (VP) projection-neurons. However, the molecular underpinnings of these circuit dysfunctions are unclear. We used RNA- sequencing to reveal alterations in the transcriptional landscape of the VP that are induced by cocaine self-administration in mice. We then probed gene expression in select VP neuronal subpopulations to isolate a circuit associated with cocaine intake. Finally, we used both overexpression and CRISPR-mediated knockdown to test the role of a gene target on cocaine- mediated behaviors as well as dendritic spine density. Our results showed that a large proportion (55%) of genes associated with structural plasticity were changed 24 hours following cocaine intake. Among them, the transcription factor Nr4a1 (Nuclear receptor subfamily 4, group A, member 1, or Nur77) showed high expression levels. We found that the VP to mediodorsal thalamus (VP[->]MDT) projection neurons specifically were recapitulating this increase in Nr4a1 expression. Overexpressing Nr4a1 in VP[->]MDT neurons enhanced drug-seeking and drug- induced reinstatement, while Nr4a1 knock down prevented self-administration acquisition and subsequent cocaine-mediated behaviors. Moreover, we showed that Nr4a1 negatively regulated spine dynamics in this specific cell subpopulation. Together, our study identifies for the first time the transcriptional mechanisms occurring in VP in drug exposure. Our study provides further understanding on the role of Nr4a1 in cocaine-related behaviors and identifies the crucial role of the VP[->]MDT circuit in drug intake and relapse-like behaviors.

neuroscience↗

bioRxiv2020

Corticostriatal Projections of Macaque Area 44

Ventrolateral frontal area 44 is implicated in inhibitory motor functions and facilitating prefrontal control over vocalization. Yet, the corticostriatal circuitry that may contribute to area 44 functions is not clear, as prior investigation of area 44 corticostriatal projections is limited. Here, we used anterograde and retrograde tracing in macaques to map the innervation zone of area 44 corticostriatal projections, quantify their strengths, and evaluate their convergence with corticostriatal projections from non-motor and motor-related frontal regions. First, terminal fields from a rostral area 44 injection site were found primarily in the central caudate nucleus, whereas those from a caudal area 44 injection site were found primarily in the ventrolateral putamen. Second, amongst sampled striatal retrograde injection sites, area 44 input as a percentage of total frontal cortical input was highest in the ventral putamen at the level of the anterior commissure. Third, area 44 projections converged with both orofacial premotor area 6VR and other motor related projections (in the putamen), and with non-motor prefrontal projections (in the caudate nucleus). These findings support the role of area 44 as an interface between motor and non-motor functional domains, possibly facilitated by rostral and caudal area 44 subregions with distinct corticostriatal connectivity profiles.

neuroscience↗

bioRxiv2018

JHU-2545 Selectively Shields Salivary Glands and Kidneys during PSMA-Targeted Radiotherapy

PURPOSEProstate-specific membrane antigen (PSMA) radiotherapy is a promising treatment for metastatic castration-resistant prostate cancer (mCRPC) with several beta or alpha particle-emitting radionuclide-conjugated small molecules showing efficacy in late stage patients. However, PSMA is also expressed in kidneys and salivary glands where specific uptake causes dose-limiting xerostomia and potential for nephrotoxicity. The PSMA inhibitor 2- (phosphonomethyl)pentanedioic acid (2-PMPA) can prevent kidney uptake in mice, but also blocks tumor uptake, precluding its clinical utility. Selective delivery of 2-PMPA to non-malignant tissues could improve the therapeutic window of PSMA radiotherapy. EXPERIMENTAL DESIGNA tri-alkoxycarbonyloxy alkyl (TrisPOC) prodrug of 2-PMPA, JHU-2545, was synthesized to enhance 2-PMPA delivery to non-malignant tissues. Preclinical pharmacokinetic and imaging experiments were conducted prior to assessment in 3 mCRPC patients receiving PSMA PET and radiotherapy. RESULTSJHU-2545 resulted in 3- and 53-fold greater exposure of 2-PMPA in rodent salivary glands (18.0 {+/-} 0.97 h*nmol/g) and kidneys (359 {+/-} 4.16 h*nmol/g) versus prostate tumor xenograft (6.79 {+/-} 0.19 h*nmol/g). JHU-2545 also blocked rodent kidneys and salivary glands uptake of the PSMA PET tracers 68Ga-PSMA-11 and 18F-DCFPyL by up to 85% without effect on tumor. In a mCRPC patient, JHU-2545 treatment prior to 68Ga-PSMA-617 administration reduced kidney SUVmax by 76% without effect on metastatic lesions. When administered prior to injection of the beta emitter 177Lu-PSMA-617, JHU-2545 shielded both the salivary glands (72% Gy reduction) and kidneys (45% Gy reduction) without effect on metastases dose. CONCLUSIONSJHU-2545 pre-treatment raises the cumulative dose limit and improves the safety and efficacy profile of PSMA radiotherapy. STATEMENT OF TRANSLATIONAL RELEVANCEProstate Specific Membrane Antigen (PSMA) molecular radiotherapy has emerged as a promising treatment for metastatic castration-resistant prostate cancer (mCRPC), but endogenous expression of PSMA in kidneys and salivary glands causes uptake into these organs resulting in dose-limiting toxicities. We describe the discovery of JHU-2545, a PSMA inhibitor prodrug that selectively blocks kidney and salivary gland uptake of PSMA theranostics without altering tumor uptake in both preclinical models and in mCRPC patients. Pretreatment of JHU-2545 thereby improves the safety and efficacy profile of the multiple PSMA radiotherapies in development.

pharmacology and toxicology↗

bioRxiv2018

The Novel Mnk1/2 Degrader VNLG-152 Potently Inhibits TNBC Tumor Growth and Metastasis

Currently, there are no effective therapies for patients with triple-negative breast cancer (TNBC), an aggressive and highly metastatic disease. Activation of eukaryotic initiation factor 4E (eIF4E) by mitogen-activated protein kinase (MAPK)-interacting kinases 1 and 2 (Mnk1/2) play a critical role in the development, progression and metastasis of TNBC. Herein, we undertook a comprehensive study to evaluate the activity of a first-in-class Mnk1/2 protein degraders, in clinically relevant models of TNBC. These studies enabled us to identify racemic VNLG-152R as the most efficacious Mnk1/2 degrader. By targeting Mnk1/2 protein degradation (activity), VNLG-152R potently inhibited both Mnk-eIF4E and mTORC1 signaling pathways and strongly regulated downstream factors involved in cell cycle regulation, apoptosis, pro-inflammatory cytokines/chemokines secretion, epithelial-mesenchymal transition (EMT) and metastasis. Most importantly, orally bioavailable VNLG-152R exhibited remarkable antitumor and antimetastatic activities against cell line and patient-derived TNBC xenograft models, with no apparent host toxicity. Collectively, these studies demonstrate that targeting Mnk-eIF4E/mTORC1 signaling with a potent Mnk1/2 degrader, VNLG-152R, is a novel therapeutic strategy that can be developed as monotherapy for effective treatment of patients with primary/metastatic TNBC.

cancer biology↗

bioRxiv2017

Glutathione S-transferases: unexpected roles in astrocyte activation and astrocyte-microglia communication during brain inflammation

Astrocytes and microglia play critical roles in brain inflammation, but their mutual regulation is not fully understood. Here we report unexpected roles for glutathione S-transferases (GSTs), particularly GSTM1, in astrocyte activation and astrocyte-mediated enhancement of microglia activation during brain inflammation. We found that astrocyte-specific silencing of GSTM1 expression in the prefrontal cortex (PFC) attenuated microglia activation in brain inflammation induced by systemic injection of lipopolysaccharides (LPS). Gstm1 silencing in astrocytes also attenuated LPS-induced TNF- production by microglia in co-culture. In astrocytes, GSTM1 was required for the activation of nuclear factor-{kappa}B (NF-{kappa}B) and c-Jun N-terminal kinases (JNK) and the production of pro-inflammatory mediators previously implicated in microglia activation, such as granulocyte-macrophage colony-stimulating factor (GM-CSF/CSF2) and chemokine (C-C motif) ligand 2 (CCL2). Similar results were also obtained with GSTT2 both in vitro and in vivo. Thus, our study identified a critical role for GSTs in priming astrocytes and enhancing microglia activation during brain inflammation.\n\nSignificant StatementAstrocytes and microglia play critical roles in brain inflammation, but it is not fully understood how astrocytes regulate microglia activation. Here we report a novel mechanism by which glutathione S-transferases (GSTs), the enzymes for phase II detoxification of xenobiotic metabolism, in astrocytes control microglia activation during brain inflammation. We found that GSTs, particularly GSTM1, regulate the induction of pro-inflammatory mediators via the activation of NF-{kappa}B and JNK in astrocytes. Our studies provide evidence that GST enzymes are active players in brain inflammation and can be targeted to regulate microglia activation.

immunology↗