Biology subjects

Jeong, S.

Publications and source records attributed to Jeong, S..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

Temporal gene regulation enables controlled expression of gas vesicles and preserves bacterial viability

Gas vesicles (GVs) are genetically encodable, air-filled protein nanostructures that have rapidly emerged as a versatile platform for biomedical imaging, cell tracking, and therapeutic delivery. However, their heterologous expression in non-native hosts such as Escherichia coli can be challenging due to the complex assembly process, which often involves around ten different proteins and can lead to proteotoxic stress and impair cell growth. Here, we report the observation of a drop in cell density occurring 8 to 16 hours after GV induction in E. coli. To address these, we developed a dual-inducer transcriptional regulation system that enables orthogonal control of GV assembly factor proteins and the shell protein over a range of stoichiometries. Sequential induction in time, in which assembly factor expression is initiated before shell protein expression, restored normal bacterial growth and prevented lysis without compromising GV production. Further analysis revealed that varying the interval between the two induction steps affected both GV yields and cellular stress. By preserving cell integrity with GV expression, our approach enhances the utility of GV-expressing bacteria in applications that demand population-wide cellular stability and facilitates their broader application in biomedical engineering and synthetic biology.

synthetic biology↗

bioRxiv2025

Microbes regulate glomerular filtration rate in health and chronic kidney disease in mice

Microbes are implicated in a variety of host physiological and pathophysiological processes. In this study, we tested the hypothesis that microbes modulate glomerular filtration rate (GFR). Microbiota were depleted in mice using oral antibiotics (ABX; a mixture of ampicillin, neomycin, and vancomycin). GFR was significantly increased in ABX-treated mice. To confirm that the increase in GFR was due to decreased microbes, we also measured GFR in germ-free (GF) mice. GFR was increased in GF mice as compared to both conventional and conventionalized GF (CGF) mice. We next used the murine adenine diet model to ask if suppressing gut microbes with ABX also increases GFR in a setting of chronic kidney disease (CKD), where GFR is impaired. In females on an adenine diet, ABX increased GFR versus adenine alone on weeks 4 and 6. In males, ABX elevated GFR on week 2. Adenine diet significantly increased plasma creatinine and kidney fibrosis; this was suppressed by ABX in both sexes. To explore the mechanism of this increase, we tested the hypothesis that altered tubuloglomerular feedback (TGF) contributes to elevated GFR using the sodium-glucose cotransporter 2 (SGLT2) inhibitor empagliflozin (EMPA); EMPA impairs Na+ reabsorption in the proximal tubule, altering TGF. We found that EMPA impaired ABX-induced GFR increases on week 3 but not week 5, suggesting that altered TGF contributes to the initial increase in GFR. In conclusion, the microbiome plays a key role in setting baseline GFR by a mechanism which partially involves TGF, and, suppressing gut microbes can elevate GFR even in CKD. Translational StatementThis study reports that GFR is elevated when gut microbes are absent or suppressed in mice, indicating a role for commensal microbes to help establish baseline GFR in health. Likewise, suppressing gut microbes also elevates GFR in a chronic kidney disease model. These data suggest a future possibility of modulating the commensal microbes to elevate GFR in a clinical setting.

physiology↗

bioRxiv2025

TCR signaling via NFATc1 constrains IL-15-induced NK-like activation of human memory CD8+ T cells

Here we investigated the regulatory mechanisms of TCR-independent bystander activation and NK-like cytotoxicity of human memory CD8+ T cells. We found that TCR signals suppressed characteristic features of IL-15-induced CD8+ T-cell activation, including increased NKG2D expression and upregulation of genes related to NK cytotoxicity and IFN response. Moreover, ionomycin suppressed IL-15-induced bystander activation and NK-like cytotoxicity, indicating that Ca2+-calcineurin signaling is responsible for TCR-mediated suppression of IL-15-induced bystander activation. In detail, NFATc1 suppressed IL-15-induced bystander activation via binding to AP-1 that is necessary for the IL-15-induced upregulation of NK cytotoxicity-related genes. Consistent with these results, calcineurin inhibitors enhanced IL-15-induced NKG2D expression in the presence of TCR signals. Additionally, we defined genes upregulated by IL-15 and downregulated by concurrent TCR signals as an IL-15-induced bystander activation gene set, and found that this gene signature was upregulated in bystander CD8+ T cells from patients with hepatitis A virus infection. This study paves the way for further investigation of bystander CD8+ T-cell activation in various pathological conditions, and its regulation. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=191 HEIGHT=200 SRC="FIGDIR/small/632884v2_ufig1.gif" ALT="Figure 1"> View larger version (60K): org.highwire.dtl.DTLVardef@1e6c320org.highwire.dtl.DTLVardef@114a23eorg.highwire.dtl.DTLVardef@1a7b9edorg.highwire.dtl.DTLVardef@9faccc_HPS_FORMAT_FIGEXP M_FIG C_FIG HighlightsO_LITCR signaling downregulates IL-15-induced transcriptomic features related to NK-like bystander activation of human memory CD8+ T cells via the Ca2+-calcineurin pathway. C_LIO_LINFATc1 suppresses IL-15-induced bystander activation via binding to AP-1, which is responsible for IL-15-induced NK-like cytotoxic activity. C_LIO_LICalcineurin inhibitors cannot suppress IL-15-induced bystander CD8+ T-cell activation, and paradoxically increase IL-15-induced NKG2D expression in the presence of TCR signals. C_LIO_LIGenes upregulated by IL-15 and downregulated by concurrent TCR signals define the gene set of bystander CD8+ T-cell activation, which was validated in disease contexts. C_LI

immunology↗

bioRxiv2024

Cervicovaginal microbial features predicts Chlamydia trachomatis spread to the upper genital tract of infected women

IntroductionChlamydia trachomatis (CT) infection can lead to pelvic inflammatory disease, infertility and other reproductive sequelae when it ascends to the upper genital tract. Factors including chlamydial burden, co-infection with other sexually-transmitted bacterial pathogens and oral contraceptive use influence risk for upper genital tract spread. Cervicovaginal microbiome composition influences CT susceptibility and we investigated if it contributes to spread by analyzing amplicon sequence variants (ASVs) derived from the V4 region of 16S rRNA genes in vaginal samples collected from women at high risk for CT infection and for whom endometrial infection had been determined. ResultsParticipants were classified as CT negative (CT-, n=77), CT positive at the cervix (Endo-, n=77), or CT positive at both cervix and endometrium (Endo+, n=66). Although we were unable to identify many significant differences between CT infected and uninfected women, differences in abundance of ASVs representing Lactobacillus iners and L. crispatus subspecies but not dominant lactobacilli were detected. Twelve informative ASVs predicted endometrial chlamydial infection (AUC=0.74), with CT ASV abundance emerging as a key predictor. We also observed a positive correlation between levels of cervically secreted cytokines previously associated with CT ascension and abundance of the informative ASVs. ConclusionOur findings suggest that vaginal microbial community members may influence chlamydial spread directly by nutrient limitation and/or disrupting endocervical epithelial integrity and indirectly by modulating pro-inflammatory signaling and/or homeostasis of adaptive immunity. Further investigation of these predictive microbial factors may lead to cervicovaginal microbiome biomarkers useful for identifying women at increased risk for disease.

microbiology↗

bioRxiv2024

PAM-flexible adenine base editing rescues hearing loss in a humanized MPZL2 mouse model harboring an East Asian founder mutation

Hearing loss is one of the most prevalent sensory disorders, but no commercial biological treatments are currently available. Here, we identified an East Asia-specific founder mutation, the homozygous c.220C>T mutation in MPZL2, that contributes to a significant proportion of hereditary deafness cases in our cohort study. We found that the disease-causing mutation could be targetable by adenine base editors (ABEs) that enable A{middle dot}T-to-G{middle dot}C base corrections without DNA double-strand breaks. To demonstrate this, we developed a humanized mouse model (hMPZL2Q74X/Q74X) that recapitulates human MPZL2 deafness and leads to progressive hearing loss. A PAM-flexible ABE variant with reduced bystander and off-target effects (ABE8eWQ-SpRY:sgRNA3) was packaged in dual adeno-associated viruses (AAVs) and injected into the inner ear of hMPZL2Q74X/Q74X mice and effectively corrected the mutation. This treatment significantly restored hearing function, improved inner ear structural integrity, and reversed altered gene expression. Base editing may hold therapeutic potential for hereditary deafness, including most cases of MPZL2 deafness.

genetics↗

bioRxiv2024

In vitro genotoxic and mutagenic potentials of combustion particles from marine fuels with different sulfur contents

Ship emissions cause serious environmental impacts and adverse effects toward human health. Therefore, the International Maritime Organization (IMO) restricted the fuel sulfur content (FSC) of marine fuels: FSC must be <0.5% m/m or <0.1% m/m in sulfur emission control areas, covering a range of fuels from distillate diesel-like fuels to low-sulfur heavy fuel oils (HFOs). As a result, ship emissions, e.g., sulfur oxides and particulate matter (PM) have been reduced. However, how FSC correlates with the toxicological potential of ship emissions is still uncertain. The objective of this study was to understand how the physical and chemical properties of particulate emissions from a marine engine operating on five marine fuels with different FSCs influence their toxicological outcome. For this scope, cytotoxic, genotoxic, mutagenic, and pro-inflammatory potentials of collected particles were evaluated in lung cell model systems. The involvement of intracellular reactive oxygen species and xenobiotic metabolism was also explored. While PM from different fuels combustion resulted in up to approximately 20% of reduction of cytotoxicity at the highest concentration, other toxicological outcomes, including clonogenic and genotoxic potentials, showed a stronger trend with the polycyclic aromatic hydrocarbon contents in PM compared with FSC. This trend was supported by evidence of a significant increase in gene mutation frequency and alterations in cellular mechanisms induced by an aromatic-rich HFO with an intermediate FSC. In conclusion, apart from reducing FSC in marine fuels, additional particle abatement systems should be considered to reduce the adverse effects of particulate emissions from shipping operations on human health.

pharmacology and toxicology↗

bioRxiv2024

AIVE: accurate predictions of SARS-CoV-2 infectivity from comprehensive analysis

An unprecedented amount of SARS-CoV-2 data has been accumulated compared with previous infectious diseases, enabling insights into its evolutionary process and more thorough analyses. This study investigates SARS-CoV-2 features as it evolved to evaluate its infectivity. We examined viral sequences and identified the polarity of amino acids in the Receptor Binding Motif (RBM) region. We detected an increased frequency of amino acid substitutions to lysine (K) and arginine (R) in Variants of Concern (VOCs). As the virus evolved to Omicron, commonly occurring mutations became fixed components of the new viral sequence. Furthermore, at specific positions of VOCs, only one type of amino acid substitution and a notable absence of mutations at D467 was detected. We found that the binding affinity of SARS-CoV-2 lineages to the ACE2 receptor was impacted by amino acid substitutions. Based on our discoveries, we developed APESS, an evaluation model evaluating infectivity from biochemical and mutational properties. In silico evaluation using real-world sequences and in vitro viral entry assays validated the accuracy of APESS and our discoveries. Using Machine Learning, we predicted mutations that had the potential to become more prominent. We created AIVE, a web-based system, accessible at https://ai-ve.org to provide infectivity measurements of mutations entered by users. Ultimately, we established a clear link between specific viral properties and increased infectivity, enhancing our understanding of SARS-CoV-2 and enabling more accurate predictions of the virus.

genomics↗

bioRxiv2024

Pre-challenge gut microbial signature predicts RhCMV/SIV vaccine efficacy in rhesus macaques

BackgroundRhCMV/SIV vaccines protect [~]59% of vaccinated rhesus macaques against repeated limiting-dose intra-rectal exposure with highly pathogenic SIVmac239M, but the exact mechanism responsible for the vaccine efficacy is not known. It is becoming evident that complex interactions exist between gut microbiota and the host immune system. Here we aimed to investigate if the rhesus gut microbiome impacts RhCMV/SIV vaccine-induced protection. MethodsThree groups of 15 rhesus macaques naturally pre-exposed to RhCMV were vaccinated with RhCMV/SIV vaccines. Rectal swabs were collected longitudinally both before SIV challenge (after vaccination) and post challenge and were profiled using 16S rRNA based microbiome analysis. ResultsWe identified [~]2,400 16S rRNA amplicon sequence variants (ASVs), representing potential bacterial species/strains. Global gut microbial profiles were strongly associated with each of the three vaccination groups, and all animals tended to maintain consistent profiles throughout the pre-challenge phase. Despite vaccination group differences, using newly developed compositional data analysis techniques we identified a common gut microbial signature predictive of vaccine protection outcome across the three vaccination groups. Part of this microbial signature persisted even after SIV challenge. We also observed a strong correlation between this microbial signature and an early signature derived from whole blood transcriptomes in the same animals. ConclusionsOur findings indicate that changes in gut microbiomes are associated with RhCMV/SIV vaccine-induced protection and early host response to vaccination in rhesus macaques.

microbiology↗

bioRxiv2024

Predicting Serotonin Detection with DNA-Carbon Nanotube Sensors Across Multiple Spectral Wavelengths

Owing to the value of DNA-wrapped single-walled carbon nanotube (SWNT) based sensors for chemically-specific imaging in biology, we explore machine learning (ML) predictions DNA-SWNT serotonin sensor responsivity as a function of DNA sequence based on the whole SWNT fluorescence spectra. Our analysis reveals the crucial role of DNA sequence in the binding modes of DNA-SWNTs to serotonin, with a smaller influence of SWNT chirality. Regression ML models trained on existing datasets predict the change in the fluorescence emission in response to serotonin, {Delta}F/F, at over a hundred wavelengths for new DNA-SWNT conjugates, successfully identifying some high- and low-response DNA sequences. Despite successful predictions, we also show that the finite size of the training dataset leads to limitations on prediction accuracy. Nevertheless, incorporating entire spectra into ML models enhances prediction robustness and facilitates the discovery of novel DNA-SWNT sensors. Our approaches show promise for identifying new chemical systems with specific sensing response characteristics, marking a valuable advancement in DNA-based system discovery.

bioengineering↗

bioRxiv2023

Regulation of adipocyte dedifferentiation at the skin wound edge

Adipocytes have diverse roles in energy storage and metabolism, inflammation, and tissue repair. Mature adipocytes have been assumed to be terminally differentiated cells. However, recent evidence suggests that adipocytes retain substantial phenotypic plasticity, with potential to dedifferentiate into fibroblast-like cells under physiological and pathological conditions. Here, we develop a two-step lineage tracing approach based on the observation that fibroblasts express platelet-derived growth factor receptor alpha (Pdgfra) while adipocytes express Adiponectin (Adipoq) but not Pdgfra. Our approach specifically traces Pdgfra+ cells that originate from Adipoq+ adipocytes. We find many traced adipocytes and fibroblast-like cells surrounding skin wounds, but only a few traced cells localize to the wound center. In agreement with adipocyte plasticity, traced adipocytes incorporate EdU, downregulate Plin1 and PPAR{gamma}, and upregulate SMA. We also investigate the role of potential dedifferentiation signals using constitutively active PDGFR mutation, Pdgfra knockout, or Tgfbr2 knockout models. We find that PDGF and TGF{beta} signaling both promote dedifferentiation, and PDGFR does so independently of TGF{beta}R2. These results demonstrate an intersectional genetic approach to trace the hybrid cell phenotype of Pdgfra+ adipocytes, which may be important for wound repair, regeneration and fibrosis.

developmental biology↗

bioRxiv2023

SOX7: Novel Autistic Gene Identified by Analysis of Multi-Omics Data

Genome-wide association studies and next generation sequencing data analyses based on DNA information have identified thousands of mutations associated with autism spectrum disorder (ASD). However, more than 99% of identified mutations are non-coding. Thus, it is unclear which of these mutations might be functional and thus potentially causal variants. Transcriptomic profiling using total RNA-sequencing has been one of the most utilized approaches to link protein levels to genetic information at the molecular level. The transcriptome captures molecular genomic complexity that the DNA sequence solely does not. Some mutations alter a genes DNA sequence but do not necessarily change expression and/or protein function. To date, few common variants reliably associated with the diagnosis status of ASD despite consistently high estimates of heritability. In addition, reliable biomarkers used to diagnose ASD or molecular mechanisms to define the severity of ASD do not exist. Therefore, it is necessary to integrate DNA and RNA testing together to identify true causal genes and propose useful biomarkers for ASD. We performed gene-based association studies with adaptive test using genome-wide association studies (GWAS) summary statistics with two large GWAS datasets (ASD 2019 data: 18,382 ASD cases and 27,969 controls [discovery data]; ASD 2017 data: 6,197 ASD cases and 7,377 controls [replication data]) which were obtained from the Psychiatric Genomics Consortium (PGC). In addition, we investigated differential expression between ASD cases and controls for genes identified in gene-based GWAS with two RNA-seq datasets (GSE211154: 20 cases and 19 controls; GSE30573: 3 cases and 3 controls). We identified 5 genes significantly associated with ASD in ASD 2019 data (KIZ-AS1, p=8.67x10-10; KIZ, p=1.16x10-9; XRN2, p=7.73x10-9; SOX7, p=2.22x10-7; LOC101929229 also known as PINX1-DT, p=2.14x10-6). Among these 5 genes, gene SOX7 (p=0.00087) and LOC101929229 (p=0.009) were replicated in ASD 2017 data. KIZ-AS1 (p=0.059) and KIZ (p=0.06) were close to the boundary of replication in ASD 2017 data. Genes SOX7 (p=0.036 in all samples; p=0.044 in white samples) indicated significant expression differences between cases and controls in the GSE211154 RNA-seq data. Furthermore, gene SOX7 was upregulated in cases than in controls in the GSE30573 RNA-seq data (p=0.0017; Benjamini-Hochberg adjusted p=0.0085). SOX7 encodes a member of the SOX (SRY-related HMG-box) family of transcription factors pivotally contributing to determining of the cell fate and identity in many lineages. The encoded protein may act as a transcriptional regulator after forming a protein complex with other proteins leading to autism. Gene SOX7 in the transcription factor family could be associated with ASD. This finding may provide new diagnostic and therapeutic strategies for ASD.

bioinformatics↗

bioRxiv2023

Serine synthesis pathway upregulated by E-cadherin is essential for the proliferation and metastasis of breast cancers

The loss of E-cadherin (E-cad), an epithelial cell adhesion molecule, has been implicated in the epithelial-mesenchymal transition (EMT), promoting invasion and migration of cancer cells and, consequently, metastasis. However, recent studies have demonstrated that E-cad supports the survival and proliferation of metastatic cancer cells, suggesting that our understanding of E-cad in metastasis is far from comprehensive. Here, we report that E-cad upregulates the de novo serine synthesis pathway (SSP) in breast cancer cells. The SSP provides metabolic precursors for biosynthesis and resistance to oxidative stress, critically beneficial for E-cad-positive breast cancer cells to achieve faster tumor growth and more metastases. Inhibition of PHGDH, a rate-limiting enzyme in the SSP, significantly and specifically hampered the proliferation of E-cad-positive breast cancer cells and rendered them vulnerable to oxidative stress, inhibiting their metastatic potential. Our findings reveal that E-cad adhesion molecule significantly reprograms cellular metabolism, promoting tumor growth and metastasis of breast cancers.

cancer biology↗

bioRxiv2023

Representing Multiple Visual Objects in the Human Brain and Convolutional Neural Networks

Objects in the real world often appear with other objects. To recover the identity of an object whether or not other objects are encoded concurrently, in primate object-processing regions, neural responses to an object pair have been shown to be well approximated by the average responses to each constituent object shown alone, indicating the whole is equal to the average of its parts. This is present at the single unit level in the slope of response amplitudes of macaque IT neurons to paired and single objects, and at the population level in response patterns of fMRI voxels in human ventral object processing regions (e.g., LO). Here we show that averaging exists in both single fMRI voxels and voxel population responses in human LO, with better averaging in single voxels leading to better averaging in fMRI response patterns, demonstrating a close correspondence of averaging at the fMRI unit and population levels. To understand if a similar averaging mechanism exists in convolutional neural networks (CNNs) pretrained for object classification, we examined five CNNs with varying architecture, depth and the presence/absence of recurrent processing. We observed averaging at the CNN unit level but rarely at the population level, with CNN unit response distribution in most cases did not resemble human LO or macaque IT responses. The whole is thus not equal to the average of its parts in CNNs, potentially rendering the individual objects in a pair less accessible in CNNs during visual processing than they are in the human brain.

neuroscience↗

bioRxiv2023

Distinct prefrontal projections conversely orchestrate social competition and hierarchy

Social animals compete for limited resources, resulting in a social hierarchy. Although different neuronal subpopulations in the medial prefrontal cortex (mPFC), a hub brain region of social hierarchy, encode distinct social competition behaviors, their identities and associated molecular underpinnings have not yet been identified. In this study, we found that mPFC neurons projecting to the nucleus accumbens (mPFC-NAc) encode social winning behavior, whereas mPFC neurons projecting to the ventral tegmental area (mPFC-VTA) encode social losing behavior by monitoring and manipulating neural circuit activity. High-throughput single-cell transcriptomic analysis and projection-specific genetic manipulation revealed that the expression level of POU domain, class 3, transcription factor 1 (Pou3f1) in mPFC-VTA neurons controls social hierarchy. Optogenetic activation of mPFC-VTA neurons increases Pou3f1 expression and lowers social rank. Together, these data demonstrate that discrete activity and gene expression in separate mPFC projections oppositely orchestrate social competition and hierarchy.

neuroscience↗

bioRxiv2022

Near Infrared Nanosensors Enable Optical Imaging of Oxytocin with Selectivity over Vasopressin in Acute Mouse Brain Slices

Oxytocin plays a critical role in regulating social behaviors, yet our understanding of its role in both neurological health and disease remains incomplete. Real-time oxytocin imaging probes with the spatiotemporal resolution relevant to its endogenous signaling are required to fully elucidate oxytocin function in the brain. Herein we describe a near-infrared oxytocin nanosensor (nIROx), a synthetic probe capable of imaging oxytocin in the brain without interference from its structural analogue, vasopressin. nIROx leverages the inherent tissue-transparent fluorescence of single-walled carbon nanotubes (SWCNT) and the molecular recognition capacity of an oxytocin receptor peptide fragment (OXTp) to selectively and reversibly image oxytocin. We employ these nanosensors to monitor electrically stimulated oxytocin release in brain tissue, revealing oxytocin release sites with a median size of 3 m which putatively represents the spatial diffusion of oxytocin from its point of release. These data demonstrate that covalent SWCNT constructs such as nIROx are powerful optical tools that can be leveraged to measure neuropeptide release in brain tissue.

bioengineering↗

bioRxiv2021

Machine learning enables discovery of DNA-carbon nanotube sensors for serotonin

DNA-wrapped single walled carbon nanotube (SWNT) conjugates have remarkable optical properties leading to their use in biosensing and imaging applications. A critical limitation in the development of DNA-SWNT sensors is the current inability to predict unique DNA sequences that confer a strong analyte-specific optical response to these sensors. Here, near-infrared (nIR) fluorescence response datasets for ~100 DNA-SWNT conjugates, narrowed down by a selective evolution protocol starting from a pool of ~1010 unique DNA-SWNT candidates, are used to train machine learning (ML) models to predict new unique DNA sequences with strong optical response to neurotransmitter serotonin. First, classifier models based on convolutional neural networks (CNN) are trained on sequence features to classify DNA ligands as either high response or low response to serotonin. Second, support vector machine (SVM) regression models are trained to predict relative optical response values for DNA sequences. Finally, we demonstrate with validation experiments that integrating the predictions of ensembles of the highest quality CNN classifiers and SVM regression models leads to the best predictions of both high and low response sequences. With our ML approaches, we discovered five new DNA-SWNT sensors with higher fluorescence intensity response to serotonin than obtained previously. Overall, the explored ML approaches introduce an important new tool to predict useful DNA sequences, which can be used for discovery of new DNA-based sensors and nanobiotechnologies. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=100 SRC="FIGDIR/small/457145v1_ufig1.gif" ALT="Figure 1"> View larger version (37K): org.highwire.dtl.DTLVardef@9e1a2corg.highwire.dtl.DTLVardef@1c84e68org.highwire.dtl.DTLVardef@1939d1eorg.highwire.dtl.DTLVardef@30424e_HPS_FORMAT_FIGEXP M_FIG C_FIG

bioengineering↗

bioRxiv2021

Differential receptor crosstalk in DRD1-DRD2 heterodimer upon phasic and tonic dopamine signals

In response to phasic and tonic release, dopamine neurotransmission is regulated by its receptor subtypes, mainly dopamine receptor type 1 and 2 (DRD1 and DRD2). These dopamine receptors are known to form a heterodimer, however the receptor crosstalk between DRD1 and DRD2 was only suspected by measuring their downstream signaling products, due to the lack of methodology for selectively detecting individual activity of different dopamine receptors. Here, we develop red DRD1 sensor (R-DRD1) and green DRD2 sensor (G-DRD2) which can specifically monitor the real-time activity of DRD1 and DRD2, and apply these multicolor sensors to directly measure the receptor crosstalk in the DRD1-DRD2 heterodimer. Surprisingly, we discover that DRD1 activation in the heterodimer is inhibited only at micromolar phasic concentration of dopamine, while DRD2 activation is selectively inhibited at nanomolar tonic dopamine level. Differential receptor crosstalk in the DRD1-DRD2 heterodimer further modulates their downstream cAMP level. These data imply a novel function of the DRD1-DRD2 heterodimer at physiological dopamine levels of phasic and tonic release. Our approach utilizing multicolor receptor sensors will be useful to discover novel function of GPCR heterodimers.

neuroscience↗

bioRxiv2021

JAG1 intracellular domain acts as a transcriptional cofactor that forms an oncogenic transcriptional complex with DDX17/SMAD3/TGIF2

Jagged1 (JAG1) is a Notch ligand that contact-dependently activates Notch receptors and regulates cancer progression. The JAG1 intracellular domain (JICD1) is generated from JAG1, such as the formation of NOTCH1 intracellular domain (NICD1), however, the role of JICD1 in tumorigenicity has not been comprehensively elucidated. Herein, we revealed that JICD1 induced astrocytes to acquire several cancer stem cell properties, including tumor formation, invasiveness, stemness, and resistance to chemotherapy and radiotherapy. The transcriptome, ChIP-sequencing, and proteomic analyses revealed that JICD1 increased SOX2 expression by forming a transcriptional complex with DDX17, SMAD3, and TGIF2. Furthermore, JICD1-driven tumorigenicity was directly regulated by SOX2. Therefore, our results demonstrated that, like NICD1, JICD1 acts as a transcriptional cofactor in the formation of the DDX17/SMAD3/TGIF2 transcriptional complex, leading to oncogenic transformation.

molecular biology↗