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Kang, J.

Publications and source records attributed to Kang, J..

At least 73 records · Page 4Linked to original sources

Deep Gaussian Process with Uncertainty Estimation for Microsatellite Instability and Immunotherapy Response Prediction Based on Histology

Determining tumor microsatellite status has significant clinical value because tumors that are microsatellite instability-high (MSI-H) or mismatch repair deficient (dMMR) respond well to immune check-point inhibitors (ICIs) and oftentimes not to chemotherapeutics. We propose MSI-SEER, a deep Gaussian process-based Bayesian model that analyzes H&E whole-slide images in weakly-supervised-learning to predict microsatellite status in gastric and colorectal cancers. We performed extensive validation using multiple large datasets comprised of patients from diverse racial backgrounds. MSI-SEER achieved state-of-the-art performance with MSI prediction, which was by integrating uncertainty prediction. We achieved high accuracy for predicting ICI responsiveness by combining tumor MSI status with stroma-to-tumor ratio. Finally, MSI-SEERs tile-level predictions revealed novel insights into the role of spatial distribution of MSI-H regions in the tumor microenvironment and ICI response.

bioinformatics↗

Astrocyte regional specialization is shaped by postnatal development

Astrocytes are an abundant class of glial cells with critical roles in neural circuit assembly and function. Though many studies have uncovered significant molecular distinctions between astrocytes from different brain regions, how this regionalization unfolds over development is not fully understood. We used single-nucleus RNA sequencing to characterize the molecular diversity of brain cells across six developmental stages and four brain regions in the mouse and marmoset brain. Our analysis of over 170,000 single astrocyte nuclei revealed striking regional heterogeneity among astrocytes, particularly between telencephalic and diencephalic regions, at all developmental time points surveyed in both species. At the stages sampled, most of the region patterning was private to astrocytes and not shared with neurons or other glial types. Though astrocytes were already regionally patterned in late embryonic stages, this region-specific astrocyte gene expression signature changed dramatically over postnatal development, and its composition suggests that regional astrocytes further specialize postnatally to support their local neuronal circuits. Across mouse and marmoset, we found hundreds of species differentially expressed genes, as well as divergence in the expression of astrocytic region- and age-differentially expressed genes and the timing of astrocyte maturation relative to birth between the species. Finally, we used expansion microscopy to show that astrocyte morphology is also regionally specialized across cortex, striatum, and thalamus in the mouse.

neuroscience↗

Tunable, self-contained gene dosage control via proteolytic cleavage of CRISPR-Cas systems

The ability to modulate gene expression through modular and universal genetic tools like CRISPR-Cas has greatly advanced gene therapy for therapeutics and basic science. Yet, the inherent stochasticity of delivery methods cause variation in target gene expression at the single-cell level, limiting their applicability in systems that require more precise expression. Thus, we implement a modular incoherent feedforward loop based on proteolytic cleavage of Cas to reduce gene expression variability against the variability of vector delivery. We target a genome-integrated marker and demonstrate dosage control of gene activation and repression, post-delivery tuning, and RNA-based compatibility of the system. To illustrate therapeutic relevance, we target the gene RAI1, the haploinsufficiency and triplosensitivity of which cause two autism-related syndromes. We demonstrate dosage-controlled gene activation for both human and mouse Rai1 via viral delivery to patient-derived cell lines and mouse cortical neurons. Overall, we established a robust dosage control circuit for uniform gene expression, beneficial for basic and translational research.

synthetic biology↗

Analytical and computational solution for the estimation of SNP-heritability in biobank-scale and distributed datasets

Estimation of heritability has been a routine in statistical genetics, in particular with the increasing sample size such as biobank-scale data and distributed datasets, the latter of which has increasing concerns of privacy. Recently a randomized Haseman-Elston regression (RHE-reg) has been proposed to estimate SNP-heritability, and given sufficient iteration (B) RHE-reg can tackle biobank-scale data, such as UK Biobank (UKB), very efficiently. In this study, we present an analytical solution that balances iteration B and RHE-reg estimation, which resolves the convergence of the proposed RHE-reg in high precision. We applied the method for 81 UKB quantitative traits and estimated their SNP-heritability and test statistics precisely. Furthermore, we extended RHE-reg into distributed datasets and demonstrated their utility in real data application and simulated data. The software for estimating SNP-heritability for biobank-scale data is released: https://github.com/gc5k/gear2.

genetics↗

Patterned wireless transcranial optogenetics generates artificial perception

Synthesizing perceivable artificial neural inputs independent of typical sensory channels remains a fundamental challenge in the development of next-generation brain-machine interfaces. Establishing a minimally invasive, wirelessly effective, and miniaturized platform with long-term stability is crucial for creating a clinically meaningful interface capable of mediating artificial perceptual feedback. In this study, we demonstrate a miniaturized fully implantable wireless transcranial optogenetic encoder designed to generate artificial perceptions through digitized optogenetic manipulation of large cortical ensembles. This platform enables the spatiotemporal orchestration of large-scale cortical activity for remote perception genesis via real-time wireless communication and control, with optimized device performance achieved by simulation-guided methods addressing light and heat propagation during operation. Cue discrimination during operant learning demonstrates the wireless genesis of artificial percepts sensed by mice, where spatial distance across large cortical networks and sequential order-based analyses of discrimination performance reveal principles that adhere to general perceptual rules. These conceptual and technical advancements expand our understanding of artificial neural syntax and its perception by the brain, guiding the evolution of next-generation brain-machine communication.

neuroscience↗

G-CSF and IL-6 drive myeloid dysregulation during severe viral infection

Dysregulated myeloid states are associated with disease severity in both sepsis and COVID-19. However, their relevance in non-COVID-19 viral infection, the factors driving their induction, and their role in tissue injury remain poorly understood. We performed a meta-analysis of 1,622,180 myeloid cells from 890 COVID-19 or sepsis patients and controls across 19 published blood scRNA-seq datasets, which revealed severity-associated gene programs in both neutrophils and monocytes pointing to emergency myelopoiesis (EM). Using published bulk transcriptional data from 562 individuals with non-COVID-19 viral disease, we show that these signatures are similarly upregulated during severe influenza and RSV infection. Analysis of transcriptional and proteomic responses in tocilizumab-treated COVID-19 patients show that IL-6 signaling blockade results in a partial reduction of EM signatures and a compensatory increase in the growth factor G-CSF. Using a cellular model of human myelopoiesis, we show that both IL-6 and G-CSF stimulate the production of myeloid cells that express EM signatures in vitro. Using a mouse model of severe influenza infection, we demonstrate the effect of IL-6 and G-CSF signaling blockade on EM-associated myeloid cells, and highlight the opposing effects of EM-induced neutrophils and monocytes on tissue injury. Our study demonstrates the link between systemic cytokines and myeloid dysregulation during severe infection in humans, and highlights the cooperative role of IL-6 and G-CSF signaling in driving infection-induced myelopoiesis.

immunology↗

Experimental and Computational Insights into the Structural Dynamics of the Fc Fragment of IgG1 Subtype from Biosimilar VEGF-Trap

The constant fragment (Fc) of the Immunoglobulin G1 (IgG1) subtype is increasingly recognized as a crucial scaffold in the development of advanced therapeutics due to its enhanced specificity, efficacy, and extended half-life. A prime example is VEGF-Trap (Aflibercept), a recombinant fusion protein that merges the Fc region of the IgG1 subtype with the binding domains of vascular endothelial growth factor receptors (VEGFR)-1 and VEGFR-2. The Fc regions role in N-glycosylation is particularly important, as it significantly influences protein stability. In this study, we present the first near-physiological temperature structures of the N-glycan-bound Fc fragment of IgG1 subtype from a biosimilar VEGF-Trap, determined using the SPring-8 Angstrom Compact free electron LAser (SACLA) and the Turkish Light Source (Turkish DeLight). Comparative analysis with cryogenic structures, including our own data, reveals alternate conformations within the glycan-binding pocket. Furthermore, molecular dynamics (MD) simulations highlight an unexpected degree of structural plasticity. These findings offer new insights into the molecular basis of Fc-mediated functions and provide valuable information for the design of next-generation therapeutics.

molecular biology↗

Aberrant N-glycosylation is a therapeutic target in carriers of a common and highly pleiotropic mutation in the manganese transporter ZIP8

The treatment of defective glycosylation in clinical practice has been limited to patients with rare and severe phenotypes associated with congenital disorders of glycosylation (CDG). Carried by approximately 5% of the human population, the discovery of the highly pleiotropic, missense mutation in a manganese transporter ZIP8 has exposed under-appreciated roles for Mn homeostasis and aberrant Mn-dependent glycosyltransferases activity leading to defective N-glycosylation in complex human diseases. Here, we test the hypothesis that aberrant N-glycosylation contributes to disease pathogenesis of ZIP8 A391T-associated Crohns disease. Analysis of N-glycan branching in intestinal biopsies demonstrates perturbation in active Crohns disease and a genotype-dependent effect characterized by increased truncated N-glycans. A mouse model of ZIP8 391-Thr recapitulates the intestinal glycophenotype of patients carrying mutations in ZIP8. Borrowing from therapeutic strategies employed in the treatment of patients with CDGs, oral monosaccharide therapy with N-acetylglucosamine ameliorates the epithelial N-glycan defect, bile acid dyshomeostasis, intestinal permeability, and susceptibility to chemical-induced colitis in a mouse model of ZIP8 391-Thr. Together, these data support ZIP8 391-Thr alters N-glycosylation to contribute to disease pathogenesis, challenging the clinical paradigm that CDGs are limited to patients with rare diseases. Critically, the defect in glycosylation can be targeted with monosaccharide supplementation, providing an opportunity for genotype-driven, personalized medicine.

genomics↗

MAGMa: Your Comprehensive Tool for Differential Expression Analysis in Mass-Spectrometry Proteomic Data.

Proteomics, the study of proteins and their functions, plays a vital role in understanding biological processes. In this study, we sought to address the challenges in analyzing complex proteomic datasets, where subtle changes in protein abundance are difficult to detect. Utilizing a newly developed tool, Maximal Aggregation of Good protein signal from Mass spectrometric data (MAGMa), we demonstrated its superior performance in accurately identifying true signals while effectively filtering out noise. Here we show that MAGMa strikes a balance between sensitivity and specificity on benchmarking datasets, offering a robust solution for analyzing various quantitative proteomic datasets. These findings advance the field by providing researchers with a powerful tool to uncover subtle changes in protein abundance, contributing to our understanding of complex biological systems and potentially facilitating the discovery of new therapeutic targets.

bioinformatics↗

Normative evidence weighting and accumulation in correlated environments

The brain forms certain deliberative decisions following normative principles related to how sensory observations are weighed and accumulated over time. Previously we showed that these principles can account for how people adapt their decisions to the temporal dynamics of the observations (Glaze et al., 2015). Here we show that this adaptability extends to accounting for correlations in the observations, which can have a dramatic impact on the weight of evidence provided by those observations. We tested online human participants on a novel visual-discrimination task with pairwise-correlated observations. With minimal training, the participants adapted to uncued, trial-by-trial changes in the correlations and produced decisions based on an approximately normative weighing and accumulation of evidence. The results highlight the robustness of our brains ability to process sensory observations with respect to not just their physical features but also the weight of evidence they provide for a given decision.

neuroscience↗

An integrated microfluidic and fluorescence platform for probing in vivo neuropharmacology

Neurotechnologies and genetic tools for dissecting neural circuit functions have advanced rapidly over the past decade, although the development of complementary pharmacological method-ologies has comparatively lagged. Understanding the precise pharmacological mechanisms of neuroactive compounds is critical for advancing basic neurobiology and neuropharmacology, as well as for developing more effective treatments for neurological and neuropsychiatric disorders. However, integrating modern tools for assessing neural activity in large-scale neural networks with spatially localized drug delivery remains a major challenge. Here, we present a dual microfluidic-photometry platform that enables simultaneous intracranial drug delivery with neural dynamics monitoring in the rodent brain. The integrated platform combines a wireless, battery-free, miniaturized fluidic microsystem with optical probes, allowing for spatially and temporally specific drug delivery while recording activity-dependent fluorescence using genetically encoded calcium indicators (GECIs), neurotransmitter sensors GRABNE and GRABDA, and neuropeptide sensors. We demonstrate the performance this platform for investigating neuropharmacological mechanisms in vivo and characterize its efficacy in probing precise mechanistic actions of neuroactive compounds across several rapidly evolving neuroscience domains.

neuroscience↗

Limosilactobacillus fermentum ATG-V5 stimulates the immune response by enhancing gut microbiome and metabolite in a cyclophosphamide-induced immunosuppression mouse model

Limosilactobacillus fermentum is known to exert immunomodulatory effects. In this study, we elucidated the immunoenhancing effects and mechanisms of a novel strain of Limosilactobacillus fermentum ATG-V5. Our findings demonstrate that ATG-V5 regulates the activation and proliferation of natural killer (NK) and T cells. It induced activation effects such as increased nitric oxide (NO) production, phagocytic capacity, and cytokine generation in Raw264.7 cells, which were confirmed to occur through the ERK and pp65 pathways. Furthermore, using a cyclophosphamide (CPP) mouse model, we demonstrated the immunomodulatory efficacy of ATG-V5, including enhanced activation of NK cells, increased levels of antibodies and cytokine secretion, in mice with immunosuppression induced by CPP. Additionally, by analyzing the gut bacterial community in the mouse model, we confirmed the ability of ATG-V5 consumption to regulate the gut microbiota, thereby substantiating the potential of this strain as a promising immunoenhancing agent.

immunology↗

Ultra-secure storage and analysis of genetic data for the advancement of precision medicine

1Cloud computing provides the opportunity to store the ever-growing genotype-phenotype data sets needed to achieve the full potential of precision medicine. However, due to the sensitive nature of this data and the patchwork of data privacy laws across states and countries, additional security protections are proving necessary to ensure data privacy and security. Here we present SQUiD, a secure queryable database for storing and analyzing genotype-phenotype data. With SQUiD, genotype-phenotype data can be stored in a low-security, low-cost public cloud in the encrypted form, which researchers can securely query without the public cloud ever being able to decrypt the data. We demonstrate the usability of SQUiD by replicating various commonly used calculations such as polygenic risk scores, cohort creation for GWAS, MAF filtering, and patient similarity analysis both on synthetic and UK Biobank data. Our work represents a new and scalable platform enabling the realization of precision medicine without security and privacy concerns.

bioinformatics↗

Neuroprotective role of Hippo signaling by microtubule stability control in C. elegans

The evolutionarily conserved Hippo (Hpo) pathway has been shown to impact early development and tumorigenesis by governing cell proliferation and apoptosis. However, its post-developmental roles are relatively unexplored. Here, we demonstrate its roles in post-mitotic cells by showing that defective Hpo signaling accelerates age-associated structural and functional decline of neurons in C. elegans. Loss of wts-1/LATS, the core kinase of the Hpo pathway, resulted in premature deformation of touch neurons and impaired touch responses in a yap-1/YAP-dependent manner, the downstream transcriptional co-activator of LATS. Decreased movement as well as microtubule destabilization by treatment with colchicine or disruption of microtubule stabilizing genes alleviated the neuronal deformation of wts-1 mutants. Colchicine exerted neuroprotective effects even during normal aging. In addition, the deficiency of a microtubule-severing enzyme spas-1 also led to precocious structural deformation. These results consistently suggest that hyper-stabilized microtubules in both wts-1-deficient neurons and normally aged neurons are detrimental to the maintenance of neuronal structural integrity. In summary, Hpo pathway governs the structural and functional maintenance of differentiated neurons by modulating microtubule stability, raising the possibility that the microtubule stability of fully developed neurons could be a promising target to delay neuronal aging. Our study provides potential therapeutic approaches to combat age- or disease-related neurodegeneration.

developmental biology↗

Misspellings or miscellings- non-verifiable cell lines in cancer research publications

Reproducible laboratory research relies on correctly identified reagents. We have previously described human gene research papers with wrongly identified nucleotide sequence reagent(s), including papers studying miR-145. Manually verifying reagent identities in more recent miR-145 papers found 20/36 (56%) and 6/36 (17%) miR-145 papers with misidentified nucleotide sequence reagent(s) and human cell line(s), respectively. We also found 5 cell line identifiers in two miR-145 papers with wrongly identified nucleotide sequences and cell lines, and 18 identifiers published elsewhere that did not correspond to indexed cell lines. These cell line identifiers were described as non-verifiable, as their identities appeared uncertain. Studying 420 papers that mentioned 8 different non-verifiable cell line identifier(s) found 235 papers (56%) that appeared to refer to BGC-803, BSG-803, BSG-823, GSE-1, HGC-7901, HGC-803 and/or MGC-823 as independent cell lines. We could not find publications describing how these cell lines were established, and they were not indexed in claimed externally accessible cell line repositories. While some papers stated that STR profiles had been generated for BGC-803, GSE-1 and/or MGC-823 cells, no STR profiles were identified. In summary, non-verifiable human cell lines represent new challenges to research reproducibility and require further investigation to clarify their identities. Novelty and Impact StatementThrough verifying reagent identities in research publications, our team found 23 non-verifiable human cell line identifiers, most of which could represent misspellings of contaminated cancer cell lines. Of 8 identifiers studied in detail, 7 non-verifiable identifiers were unexpectedly referred to as independent cell lines across 235 publications. We therefore describe a process "miscelling", where published cell lines lack descriptions of how they were established, cannot be found in claimed external repositories and lack STR profiles.

cancer biology↗

Mapping protein-metabolite interactions in E. coli by integrating chromatographic techniques and co-fractionation mass spectrometry.

In our pursuit of understanding the protein-metabolite interactome, we introduced PROMIS, a co-fractionation mass spectrometry (CF-MS) technique focusing on biosynthetic and regulatory processes. However, the challenge lies in distinguishing true interactors from coincidental co-elution when a metabolite co-fractionates with numerous proteins. To address this, we integrated two chromatographic techniques-- size exclusion and ion exchange--to enhance the mapping of protein-metabolite interactions (PMIs) in Escherichia coli. This integration aims to refine the PMI network by considering size and charge characteristics, resulting in 994 interactions involving 51 metabolites and 465 proteins. The PMI network is enriched for known and predicted interactions validating our approachs efficacy. Furthermore, the analysis of protein targets for different metabolites revealed novel functional insights, such as the connection between proteinogenic dipeptides and fatty acid biosynthesis. Notably, we uncovered an inhibitory interaction between the riboflavin degradation product lumichrome and orotate phosphoribosyltransferase (PyrE), a key enzyme in de novo pyrimidine synthesis. Lumichrome supplementation mimicked the biofilm formation inhibition observed in a{Delta} pyrE mutant strain, suggesting lumichrome role in integrating pyrimidine and riboflavin metabolism with quorum sensing and biofilm formation. In summary, our integrated chromatographic approach significantly advances PMI mapping, offering novel insights into functional associations and potential regulatory mechanisms in E. coli.

biochemistry↗

Human Amniotic Epithelial Cells Promote Chx10-/Pax6+ Muller Glia Subpopulation Reprogramming into Photoreceptor-like Cells

Reprogramming Muller glia to regenerate neurons is a promising strategy for treating retinal degeneration, but whether Muller glia contain subpopulations with different regenerative fates remains unclear. Here, using single-cell RNA-seq analysis and Muller glia lineage-tracing mice with retinal degeneration, we reveal that Muller glia were heterogeneous and identify a specific Muller glial subpopulation (Chx10-/Pax6+) in healthy retinas that is activated and migrate to the outer nuclear layer (ONL) during photoreceptor degeneration. Transplantation of human amniotic epithelial cells (hAECs) facilitates the activation and extensive migration of the Chx10-/Pax6+ Muller glial subpopulation to the ONL, where they are reprogrammed into photoreceptor-like cells. Mechanistically, hAECs degrade the inhibitory extracellular matrix through regulating matrix metalloproteinases, which probably induces remodeling of the microenvironment of Muller glia and contributes to cell reprogramming. Consequently, hAEC transplantation improves visual function in rd10 mice. Our findings uncover a distinctive Muller glial subpopulation with the potential for reprogramming into photoreceptors.

cell biology↗

Harnessing the regenerative potential of interleukin11 to enhance heart repair

Balancing between regenerative processes and fibrosis is crucial for heart repair, yet strategies regulating this balance remain a barrier to developing therapies. While Interleukin11 (IL11) is known as a fibrotic factor, its contribution to heart regeneration is poorly understood. We uncovered that il11a, an Il11 homolog in zebrafish, can trigger robust regenerative programs in zebrafish hearts, including cardiomyocytes proliferation and coronary expansion, even in the absence of injury. However, prolonged il11a induction in uninjured hearts causes persistent fibroblast emergence, resulting in fibrosis. While deciphering the regenerative and fibrotic effects of il11a, we found that il11-dependent fibrosis, but not regeneration, is mediated through ERK activity, suggesting to potentially uncouple il11a dual effects on regeneration and fibrosis. To harness the il11as regenerative ability, we devised a combinatorial treatment through il11a induction with ERK inhibition. This approach enhances cardiomyocyte proliferation with mitigated fibrosis, achieving a balance between regenerative processes and fibrosis. Thus, we unveil the mechanistic insights into regenerative il11 roles, offering therapeutic avenues to foster cardiac repair without exacerbating fibrosis.

developmental biology↗