Biology subjects

Choi, S. H.

Publications and source records attributed to Choi, S. H..

At least 19 recordsLinked to original sources

bioRxiv2026

Proton-Activated Chloride Channel 1 (PACC1) is essential for innate host defense against bacterial sepsis

Bacterial sepsis remains a devastating clinical problem. Here, we describe a protective role for the recently discovered acid-sensitive, proton-activated chloride channel, PACC1 (PAC/ASOR/TMEM206), during sepsis. Initially, we found PACC1 was enriched in healthy human and mouse mononuclear phagocytes, particularly macrophages, and differentially regulated by inflammatory stimuli, suggesting PACC1 involvement in innate immunity. To further investigate, we generated de novo Pacc1 knockout (-/-) mice, which presented without major immunologic abnormalities at baseline. Compared to wildtype (WT), Pacc1-/- myeloid cells showed normal phagocytic uptake of acid-insensitive Escherichia coli BioParticles, but impaired development of the acidifying phagolysosome using acid-sensitive E. coli BioParticles. Transcriptomic profiling of Pacc1-/- macrophages revealed dysregulated phagolysosomal and cytokine networks (e.g., interferons). Because phagolysosomal bacterial clearance is essential to resolve infection, we challenged Pacc1-/- mice with intraperitoneal gram-negative E. coli sepsis. Pacc1-/- mice displayed increased bacterial burden, immune cell infiltration, inflammation, and lethality. In contrast, phagocytosis-independent E. coli lipopolysaccharide (LPS)-induced endotoxemia yielded comparable WT and Pacc1-/- survival, as well as similar inflammatory responses. Finally, we engineered Pacc1-floxed (fl/fl) mice crossed with a myeloid lineage Cre-deleter strain to interrogate myeloid cell-intrinsic PACC1 in vivo. Consistent with a predominate role for PACC1 during phagocytosis and bacterial clearance in these cells, LysM-Cre/Pacc1fl/fl mice exhibited impaired E. coli sepsis survival but indifferent endotoxemia phenotypes. In conclusion, PACC1 links sterilizing phagolysosomal activity with immune networks in sepsis pathobiology. Significance StatementBacterial sepsis remains a major global health burden. Here, we report an essential role for the recently discovered acid-sensitive chloride channel, PACC1 (PAC/ASOR/TMEM206), in protective host defense during bacterial infection and sepsis. PACC1 is highly expressed in human and mouse phagocytic myeloid cells, particularly macrophages, where it regulates phagocytic bacterial clearance and inflammatory responses. Using de novo generated mice, we show that global or myeloid cell-targeted deletion of PACC1 impairs development of phagolysosomal acidification, confers susceptibility to bacterial infection and excessive inflammation, and undermines host defense. These findings warrant further investigation of PACC1 in sepsis pathobiology.

immunology↗

bioRxiv2025

Synthesis of mRNA lipid nanoparticles for engineering GD2 CAR T and CAR NK cells against neuroblastoma

AbstractEngineering T and natural killer (NK) cells with chimeric antigen receptors (CAR) creates effective adoptive cell transfer therapies for cancer treatment. However, using viral transduction as a primary genetic modification method adds regulatory burdens and is expensive to produce at scale. Delivering mRNA encoding CAR via lipid nanoparticles (LNPs) has been explored as a potent non-viral method to generate CAR immune cells. Still, it has not been optimized for CAR treatment of neuroblastoma to date. An LNP formulation to deliver mRNA encoding a GD2 CAR into human T and NK cells was designed and characterized by dynamic light scattering for size distribution, z-average diameter, polydispersity index, and {zeta} potential. Fluorescent reporter detection persisted for more than 1 week after mRNA LNP transfection, without affecting T or NK cell viability. The potency of GD2 CAR T cells with 79.9% reporter positivity and GD2 CAR NK cells with 26.6% reporter positivity was assessed in vitro against the GD2+ neuroblastoma cell line CHLA20. GD2 CAR T or CAR NK cells could effectively target and kill neuroblastoma cells in a dose-dependent fashion, and GD2 CAR T cells showed increased IFN{gamma} production. This study shows mRNA LNPs are a promising non-viral approach for generating GD2 CAR T and CAR NK cells, potentially offering a safer and more cost-effective alternative to current viral vector-based methods.

cancer biology↗

bioRxiv2025

O-mannosylation and protein maturation check-points represent therapeutic opportunities in BRAF fusion protein oncogenesis

Fusions between protein-coding genes are common oncogenic drivers across cancers, typically pairing a proto-oncogene with partner that does not independently drive cancer. In all therapeutically actionable fusions, the proto-oncogene is the drug target, the contributions to oncogenicity of the fusion partner have largely been ignored. We studied the role of BRAF fusion partners and found that they are necessary for transformation. In the setting of KIAA1549::BRAF, the most common fusion protein across brain tumors, we found that KIAA1549 is necessary for the oncogenicity of KIAA1549::BRAF and engenders a striking and specific dependency on the protein O-mannosyltransferase complex (POMT1/2). Specifically, we show that genetic silencing or pharmacologic inhibition of the protein O-mannosyltransferase complex (POMT1/2) reverses fusion-induced transformation, thereby representing a novel and MAPK independent therapeutic target. Furthermore, POMT1/2 is required to glycosylate and enable maturation of the K::B fusion protein. These findings represent a proof-of-concept for targeting the partners in oncogenic fusions as a potential cancer therapeutic strategy.

cancer biology↗

bioRxiv2025

Multiple-testing corrections in case-control studies using identity-by-descent segments

Identity-by-descent (IBD) mapping provides complementary signals to genome-wide association studies (GWAS) when multiple causal haplotypes or variants are present, but not directly tested. However, failing to correct for multiple testing in case-control studies using IBD segments can lead to false discoveries. We propose the difference between case-case and control-control IBD rates as an IBD mapping statistic. For our hypothesis test, we use a computationally efficient approach from the stochastic processes literature to derive genome-wide significance levels that control the family-wise error rate (FWER). Whole genome simulations indicate that our method conservatively controls the FWER. Because positive selection can lead to false discoveries, we pair our IBD mapping approach with a selection scan so that one can contrast results for evidence of confounding due to recent sweeps or other mechanisms, like population structure, that increase IBD sharing. We developed automated and reproducible workflows to phase haplotypes, call local ancestry probabilities, and perform the IBD mapping scan, the former two tasks being important preprocessing steps for haplotype analyses. We applied our methods to search for Alzheimers disease (AD) risk loci in the Alzheimers Disease Sequencing Project (ADSP) genome data. We identified six genome-wide significant signals of AD risk among samples genetically similar to African and European reference populations and self-identified Amish samples. Variants in the six potential risk loci we detected have previously been associated with AD, dementia, and memory decline. Three genes at two potential risk loci have already been nominated as therapeutic targets. Overall, our scalable approach makes further use of large consortia resources, which are expensive to collect but provide insights into disease mechanisms. HighlightsO_LIWe propose a computationally efficient method to address multiple testing when scanning along the genome for differences in identity-by-descent rates of case-case and control-control pairs. C_LIO_LIWhole genome simulations indicate that our method conservatively controls the desired family-wise error rate. C_LIO_LIWe performed three case-control scans from ancestry cohorts in the Alzheimers Disease Sequencing Project, detecting six genome-wide significant signals around potential risk loci. C_LIO_LIWe show that positive selection can confound IBD mapping tests in samples genetically similar to Europeans. C_LI

genetics↗

bioRxiv2025

Exploration of Novel Biomarkers through a Precision Medicine Approach Using Multi-omics and Brain Organoids in Patients with Atypical Depression and Psychotic Symptoms

Major depressive disorder (MDD) with atypical features accompanied by psychotic symptoms represents a severe and under-researched subtype of depression and severe mental illness, characterized by significant personal and social impact. This study aims to explore novel biomarkers through a precision medicine approach by integrating clinical data, white blood cell (WBC) single-cell RNA sequencing (scRNA-seq), plasma proteomics, and brain organoid models to uncover immunological and neurological alterations in patients with this condition. Patients exhibited elevated stress, anxiety, and depression levels, with increased WBC counts. Plasma proteomic profiling identified an upregulation of proteins implicated in synaptic formation, including Doublecortin-Like Kinase 3 (DCLK3) and Calcyon (CALY), as well as immune-related proteins such as Complement Component 5 (C5). WBC scRNA-seq revealed significant neutrophil and monocyte transcriptomic alterations, suggesting increased inflammation and immune dysregulation. Patient-derived brain organoids display reduced growth and distinct gene expression patterns compared to controls, particularly under dexamethasone-induced stress conditions. Integrating multi-omics data and brain organoid models offers a novel framework for understanding the pathophysiology of psychiatric disorder, which is one of the most complex disorders.

neuroscience↗

bioRxiv2024

Prelimbic corticopontine neurons gate extinction learning

The prelimbic cortex is essential for association of temporally separated events, and impedes extinction of learned association. The network mechanism underlying reversal learning, however, remains elusive. Here, we found that mitochondria-dependent post-tetanic potentiation at synapses onto prelimbic corticopontine neurons impedes extinction learning without affecting initial associative learning. Rats underwent trace fear conditioning followed by extinction sessions. Pharmacological inhibition of post-tetanic potentiation using tetaraphenylphosphnium (TPP), a mitochondrial Ca2+ release blocker, accelerated extinction of trace fear memory, leaving trace fear memory formation intact. Optogenetic inhibition of corticopontine, but not commissural, neurons phenocopied these effects. Electrophysiological recordings and Ca2+ imaging revealed that TPP treatment reduced the persistent activity of corticopontine neurons encoding tone presentation. Mechanistically, associative learning triggers the bursting activity of prelimbic pyramidal neurons that induces post-tetanic potentiation of corticopontine neurons, an effect blocked by TPP treatment. Thus, we identified a prelimbic cell type- and local circuit-specific mechanism that selectively gates extinction learning.

neuroscience↗

bioRxiv2023

Noninvasive focal transgene delivery with viral neuronal tracers in the marmoset monkey

Although preclinical neuroscientific modeling species permit invasive intracranial delivery of targeted neurotropic agents, direct intracranial injections are not readily translatable to clinical therapeutics. Transcranial focused ultrasound (tFUS) has been identified as a technique to circumvent surgical injections altogether by transiently opening the blood-brain barrier (BBB) with selective focus. We have recently characterized the ability to focally deliver substances across the BBB in the marmoset, a non-human primate model with similar husbandry requirements to rodents but with cortical topologies more similar to humans. Here, we establish a reliable method for selectively delivering adeno-associated viral vectors (AAVs) across the BBB in marmoset frontal cortex with tFUS and demonstrate long-range anterograde neuronal tracing. Using a single-element 1.46 MHz transducer, we focally perturbed the BBB ([~]1 x 2 mm) in area 8aD of frontal cortex in four adult marmoset monkeys using low-intensity focused ultrasound aided by microbubbles. We confirmed BBB opening via a gadolinium-enhanced MRI at 9.4 T prior to AAV delivery. Within an hour of opening the BBB, either AAV2 or AAV9 was delivered systemically via tail-vein injection. Four to six weeks later, animals were sacrificed, and microscopy was performed to confirm the presence of neurons transduced as indicated by EGFP or mCherry fluorescence. In all four marmosets, neurons were observed at the site of BBB perturbation, with AAV2 showing an exiguous distribution of transduced neurons when compared to AAV9. The results are compared to direct intracortical injections of anterograde tracers into area 8aD and similar (albeit sparser) long-range connectivity was observed. With evidence of transduced neurons specific to the region of BBB opening as well as long-distance tracing, we establish a framework for focal noninvasive transgene delivery to the marmoset brain. This technique will be of utility for the burgeoning marmoset model, with applications for noninvasive delivery of therapeutics, genetic delivery of precursors for techniques like two-photon imaging, or neuronal tracing across the lifespan.

neuroscience↗

bioRxiv2022

CRISPR/Cas-based precision gene replacement in plants via homologous recombination-independent approaches

Precise gene or allele replacement is a desirable technology, but implementing it in plants remains challenging. CRISPR-Cas-based approaches, such as gene targeting (GT) and prime editing (PE), have opened up new possibilities for precise gene replacement in plants. However, their editing size and efficiency still need improvement. Recently, strategies using canonical nonhomologous end-joining (cNHEJ) and microhomology-mediated end joining (MMEJ) have been considered promising alternatives for precise gene replacement in yeast and mammals. However, these approaches have not been extensively explored and applied to plants. Here, we proposed and tested a CRISPR-Cas-based tool, termed PREMJ (precision gene replacement via microhomology-mediated end joining), for precision gene replacement in plants. The PREMJ strategy employing 20-bp microhomology MMEJ donors ([~]100 bp lengths) and a canonical nonhomologous end-joining (cNHEJ) inhibitor, NU7441, produced high targeted gene replacement efficiencies, up to 1.60 {+/-} 0.14, 4.47 {+/-} 1.98, and 8.98 {+/-} 4.73 % in protoplasts of tomato, lettuce, and cabbage, respectively. Our data also revealed the critical impacts of the microhomology length and NU7441 concentration on PREMJ-based precision gene editing in plants. Although obtaining edited plants remains challenging due to inefficient protoplast regenerations and Agrobacterium-mediated delivery, PREMJ may significantly contribute to precision gene editing in plants competent to PREMJ complex delivery and plant regeneration. Key MessageWe designed and tested a method, termed PREMJ, for precise gene replacement using the CRISPR-Cas-mediated double-stranded break (DSB) formation and repairing the DSBs via microhomology-mediated end joining (MMEJ) with MMEJ donor template carrying desired base changes and microhomologies flanking the DSB ends. PREMJ showed feasibility in precise gene replacement in protoplasts of tomatoes, lettuce, and cabbage, albeit its efficacy in Agrobacterium-mediated plant transformation requires further optimization.

synthetic biology↗

bioRxiv2021

Adjusting for Common Variant Polygenic Scores Improves Yield in Rare Variant Association Analyses

With the emergence of large-scale sequencing data, methods for improving power in rare variant analyses (RVAT) are needed. Here, we show that adjusting for common variant polygenic scores improves the yield in gene-based RVAT across 65 quantitative traits in the UK Biobank (up to 20% increase at =2.6x10-6), without a marked increase in false-positive rates or genomic inflation. Our results illustrate how adjusting for common variant effects can aid in rare variant association discovery.

genomics↗

bioRxiv2021

Rapid Biomarker Screening of Alzheimer's Disease by Machine Learning and Graphene-Assisted Raman Spectroscopy

As the most common cause of dementia, the study of Alzheimers disease (AD) faces challenges in terms of understanding the cause, monitoring the pathogenesis, and developing early diagnosis and effective treatment. Rapid and accurate identification of AD biomarkers in the brain is critical to provide key insights into AD and facilitate the development of early diagnosis methods. In this work, we developed a platform that enables a rapid screening of AD biomarkers by employing graphene-assisted Raman spectroscopy and machine learning interpretation in AD transgenic animal brains. Specifically, we collected Raman spectra on slices of mouse brains with and without AD and used machine learning to classify AD and non-AD spectra. By contacting monolayer graphene with the brain slices, the accuracy was significantly increased from 77% to 98% in machine learning classification. Further, using linear supporting vector machine (SVM), we identified a spectral feature importance map that reveals the importance of each Raman wavenumber in classifying AD and non-AD spectra. Based on this spectral feature importance map, we identified AD biomarkers including A{beta} and tau proteins, and other potential biomarkers, such as triolein, phosphatidylcholine, and actin, which have been confirmed by other biochemical studies. Our Raman-machine learning integrated method with interpretability is promising to greatly accelerate the study of AD and can be extended to other tissues, biofluids, and for various other diseases.

neuroscience↗

bioRxiv2021

Tracking of Anopheles stephensi in Ethiopia using mitochondrial DNA reveals pattern of spread

The recent detection of the South Asian malaria vector Anopheles stephensi in the Horn of Africa (HOA) raises concerns about the impact of this mosquito on malaria transmission in the region. The mode and history of introduction is important for predicting the likelihood of continued introduction and future spread. Analysis of An. stephensi genetic diversity and population structure can provide insight into the history of the mosquito in the HOA. We investigated genetic diversity of An. stephensi in eastern Ethiopia where detection suggests a range expansion to this region to understand the history of this invasive population. We sequenced the cytochrome oxidase subunit I (COI) and cytochrome B gene (CytB) in 187 An. stephensi collected from 10 sites in Ethiopia in 2018. Phylogenetic analyses using a maximum-likelihood approach and minimum spanning network were conducted for Ethiopian sequences. Molecular identification of bloodmeal sources was also performed using universal vertebrate CytB sequencing. Six COI-CytB haplotypes were observed based on five segregating sites, with the highest number of haplotypes in the northeastern sites (Semera, Bati, and Gewana towns) relative to the southeastern sites (Kebridehar, Godey, and Degehabur) in eastern Ethiopia. In the phylogenetic and network analysis, we observed population differentiation based on the distribution of the haplotypes across the northeastern and central sites (Erer Gota, Dire Dawa, and Awash Sebat Kilo) compared to the southeastern sites and evidence of a South Asian origin of the HOA An. stephensi lineages. The presence of the putative South Asian haplotype of origin at sites closest to Ethiopias northeastern borders support route of introductions into Ethiopia from the northeast. Finally, molecular bloodmeal analysis revealed evidence of feeding on bovines, goats, dogs, and humans, as well as evidence of multiple (mixed) blood meals. In conclusion, we find support for the hypothesis for the recent expansion of An. stephensi into southeastern Ethiopia with multiple introductions. We also find evidence that supports the hypothesis that HOA An. stephensi populations originate from South Asia rather than the Arabian Peninsula. The evidence of both zoophagic and anthropophagic feeding support the potential for livestock movement to play a role in vector spread in this region.

ecology↗

bioRxiv2021

Mutational impact and signature of ionizing radiation

Whole-genome sequencing (WGS) of human tumors and normal cells exposed to various carcinogens has revealed distinct mutational patterns that provide deep insights into the DNA damage and repair processes. Although ionizing radiation (IR) is conventionally known as a strong carcinogen, its genome-wide mutational impacts have not been comprehensively investigated at the single-nucleotide level. Here, we explored the mutational landscape of normal single-cells after exposure to the various levels of IR. On average, 1 Gy of IR exposure generated [~]16 mutational events with a spectrum consisting of predominantly small nucleotide deletions and a few characteristic structural variations. In [~]30% of the post-irradiated cells, complex genomic rearrangements, such as chromoplexy, chromothripsis, and breakage-fusion-bridge cycles, were resulted, indicating the stochastic and chaotic nature of DNA repair in the presence of the massive number of concurrent DNA double-strand breaks. These mutational signatures were confirmed in the genomes of 22 IR-induced secondary malignancies. With high-resolution genomic snapshots of irradiated cells, our findings provide deep insights into how IR-induced DNA damage and subsequent repair processes operate in mammalian cells.

genomics↗

bioRxiv2020

Rare Genetic Variation Underlying Human Diseases and Traits: Results from 200,000 Individuals in the UK Biobank

BackgroundMany human diseases are known to have a genetic contribution. While genome-wide studies have identified many disease-associated loci, it remains challenging to elucidate causal genes. In contrast, exome sequencing provides an opportunity to identify new disease genes and large-effect variants of clinical relevance. We therefore sought to determine the contribution of rare genetic variation in a curated set of human diseases and traits using a unique resource of 200,000 individuals with exome sequencing data from the UK Biobank. Methods and ResultsWe included 199,832 participants with a mean age of 68 at follow-up. Exome-wide gene-based tests were performed for 64 diseases and 23 quantitative traits using a mixed-effects model, testing rare loss-of-function and damaging missense variants. We identified 51 known and 23 novel associations with 26 diseases and traits at a false-discovery-rate of 1%. There was a striking risk associated with many Mendelian disease genes including: MYPBC3 with over a 100-fold increased odds of hypertrophic cardiomyopathy, PKD1 with a greater than 25-fold increased odds of chronic kidney disease, and BRCA2, BRCA1, ATM and PALB2 with 3 to 10-fold increased odds of breast cancer. Notable novel findings included an association between GIGYF1 and type 2 diabetes (OR 5.6, P=5.35x10-8), elevated blood glucose, and lower insulin-like-growth-factor-1 levels. Rare variants in CCAR2 were also associated with diabetes risk (OR 13, P=8.5x10-8), while COL9A3 was associated with cataract (OR 3.4, P=6.7x10-8). Notable associations for blood lipids and hypercholesterolemia included NR1H3, RRBP1, GIGYF1, SCGN, APH1A, PDE3B and ANGPTL8. A number of novel genes were associated with height, including DTL, PIEZO1, SCUBE3, PAPPA and ADAMTS6, while BSN was associated with body-mass-index. We further assessed putatively pathogenic variants in known Mendelian cardiovascular disease genes and found that between 1.3 and 2.3% of the population carried likely pathogenic variants in known cardiomyopathy, arrhythmia or hypercholesterolemia genes. ConclusionsLarge-scale population sequencing identifies known and novel genes harboring high-impact variation for human traits and diseases. A number of novel findings, including GIGYF1,represent interesting potential therapeutic targets. Exome sequencing at scale can identify a meaningful proportion of the population that carries a pathogenic variant underlying cardiovascular disease.

genetics↗

bioRxiv2020

Phenome-wide association study of a comprehensive health check-up database in a Korea population: Clinical application & trans-ethnic comparison

AbstractsO_ST_ABSBackgroundC_ST_ABSThe expanding use of the phenome-wide association study (PheWAS) faces challenges in the context of using International Classification of Diseases billing codes for phenotype definition, imbalanced study population ethnicity, and constrained application of the results to clinical practice or research. MethodsWe performed a PheWAS utilizing deep phenotypes corroborated by comprehensive health check-ups in a Korean population, along with trans-ethnic comparisons through the UK Biobank and Biobank Japan Project. Network analysis, visualization of cross-phenotype mapping, and causal inference mapping with Mendelian randomization were conducted in order to make robust, clinically applicable interpretations. ResultsOf the 136 phenotypes extracted from the health check-up database, the PheWAS associated 65 phenotypes with 14,101 significant variants (P < 4.92x10-10). In the association study for body mass index, our population showed 583 exclusive loci relative to the Japanese population and 669 exclusive loci relative to the European population. In the meta-analysis with Korean and Japanese populations, 72.5% of phenotypes had uniquely significant variants. Tumor markers and hematologic phenotypes had a high degree of phenotype-phenotype pairs. By Mendelian randomization, one skeletal muscle mass phenotype was causal and two were outcomes. Among phenotype pairs from the genotype-driven cross-phenotype associations, 71.65% also demonstrated penetrance in correlation analysis using a clinical database. ConclusionsThis comprehensive analysis of PheWAS results based on a health check-up database will provide researchers and clinicians with a panoramic overview of the networks among multiple phenotypes and genetic variants, laying groundwork for the practical application of precision medicine.

genetics↗

bioRxiv2020

Deep learning enables genetic analysis of the human thoracic aorta

The aorta is the largest blood vessel in the body, and enlargement or aneurysm of the aorta can predispose to dissection, an important cause of sudden death. While rare syndromes have been identified that predispose to aortic aneurysm, the common genetic basis for the size of the aorta remains largely unknown. By leveraging a deep learning architecture that was originally developed to recognize natural images, we trained a model to evaluate the dimensions of the ascending and descending thoracic aorta in cardiac magnetic resonance imaging. After manual annotation of just 116 samples, we applied this model to 3,840,140 images from the UK Biobank. We then conducted a genome-wide association study in 33,420 individuals, revealing 68 loci associated with ascending and 35 with descending thoracic aortic diameter, of which 10 loci overlapped. Integration of common variation with transcriptome-wide analyses, rare-variant burden tests, and single nucleus RNA sequencing prioritized SVIL, a gene highly expressed in vascular smooth muscle, that was significantly associated with the diameter of the ascending and descending aorta. A polygenic score for ascending aortic diameter was associated with a diagnosis of thoracic aortic aneurysm in the remaining 391,251 UK Biobank participants who did not undergo imaging (HR = 1.44 per standard deviation; P = 3.7{middle dot}10-12). Defining the genetic basis of the diameter of the aorta may enable the identification of asymptomatic individuals at risk for aneurysm or dissection and facilitate the prioritization of potential therapeutic targets for the prevention or treatment of aortic aneurysm. Finally, our results illustrate the potential for rapidly defining novel quantitative traits derived from a deep learning model, an approach that can be more broadly applied to biomedical imaging data.

genomics↗

bioRxiv2020

Genomic evaluation of circulating proteins for drug target characterisation and precision medicine

Circulating proteins are vital in human health and disease and are frequently used as biomarkers for clinical decision-making or as targets for pharmacological intervention. By mapping and replicating protein quantitative trait loci (pQTL) for 90 cardiovascular proteins in over 30,000 individuals, we identified 467 pQTLs for 85 proteins. The pQTLs were used in combination with other sources of information to evaluate known drug targets, and suggest new target candidates or repositioning opportunities, underpinned by a) causality assessment using Mendelian randomization, b) pathway mapping using trans-pQTL gene assignments, and c) protein-centric polygenic risk scores enabling matching of plausible target mechanisms to sub-groups of individuals enabling precision medicine.

genetics↗

bioRxiv2020

Transcriptional and Cellular Diversity of the Human Heart

IntroductionThe human heart requires a complex ensemble of specialized cell types to perform its essential function. A greater knowledge of the intricate cellular milieu of the heart is critical to increase our understanding of cardiac homeostasis and pathology. As recent advances in low input RNA-sequencing have allowed definitions of cellular transcriptomes at single cell resolution at scale, here we have applied these approaches to assess the cellular and transcriptional diversity of the non-failing human heart. MethodsMicrofluidic encapsulation and barcoding was used to perform single nuclear RNA sequencing with samples from seven human donors, selected for their absence of overt cardiac disease. Individual nuclear transcriptomes were then clustered based upon transcriptional profiles of highly variable genes. These clusters were used as the basis for between-chamber and between-sex differential gene expression analyses and intersection with genetic and pharmacologic data ResultsWe sequenced the transcriptomes of 287,269 single cardiac nuclei, revealing a total of 9 major cell types and 20 subclusters of cell types within the human heart. Cellular subclasses include two distinct groups of resident macrophages, four endothelial subtypes, and two fibroblasts subsets. Comparisons of cellular transcriptomes by cardiac chamber or sex reveal diversity not only in cardiomyocyte transcriptional programs, but also in subtypes involved in extracellular matrix remodeling and vascularization. Using genetic association data, we identified strong enrichment for the role of cell subtypes in cardiac traits and diseases. Finally, intersection of our dataset with genes on cardiac clinical testing panels and the druggable genome reveals striking patterns of cellular specificity. ConclusionsUsing large-scale single nuclei RNA sequencing, we have defined the transcriptional and cellular diversity in the normal human heart. Our identification of discrete cell subtypes and differentially expressed genes within the heart will ultimately facilitate the development of new therapeutics for cardiovascular diseases.

genomics↗

bioRxiv2019

A screening platform based on epitope editing for drug discovery

The interaction between an antibody and its epitope has been daily utilized in various biological studies; however it has been rarely explored whether small molecules can alter the interaction. We discovered that small molecules could alter/edit surface properties of amyloid beta (A{beta}) epitopes, and consequently inhibit or enhance corresponding antibody recognition. Remarkably, this editing effect could generate functional changes including protein aggregation behaviors, cell cytokine secreting and in vivo microglia activation. According to this discovery, we proposed a screen platform based on epitope editing for drug discovery (SPEED). With a small library of compounds, we validated that SPEED could be used to seek new leads for A{beta} species. We also demonstrated that this platform could potentially be extended to other targets including tau protein and PD-L1 protein. The SPEED is a simple, fast and label-free screening method. We believe that the SPEED strategy could be universally applicable for seeking and validating drug candidates and imaging ligands.

biochemistry↗