Biology subjects

Chi, T.

Publications and source records attributed to Chi, T..

11 recordsLinked to original sources

bioRxiv2026

High-channel-count neural recording and stimulation platform with 5,376 simultaneous recording channels

Advancing neural interfaces requires large-scale, high-density recording technologies capable of capturing full-spectrum neural activity across cortical and subcortical regions. Here, we present a scalable approach to integrate neural electrodes with advanced application-specific integrated circuits (ASICs). Specifically, we custom-designed an ASIC with 5,376 simultaneous channels, each sampling at 20 kS/s and enabling >1.3 Gb/s total data streaming throughput. The ASIC incorporates in-pixel amplification, time-division multiplexed ADCs, and on-chip stimulation capabilities, ensuring precise signal acquisition with minimal power consumption while maintaining a low noise level of 5.5 {micro}Vrms. We further developed an interconnect strategy using gold bump bonding, which allows for high-density integration of the flexible probe and rigid chip. We demonstrate the capacity of this platform through the integration with a flexible ECoG array. The resulting device allows for the high-resolution mapping of in vivo field potentials on the cortical surfaces of rat brains, supported by the precise localization of evoked sensory activities. These results prove an effective approach towards highly integrated neural interfaces with applications in brain-computer interfaces, neuroprosthetics, and large-scale functional brain mapping.

bioengineering↗

bioRxiv2025

Optimized CRISPR Perturbation Illuminates the Functions of RNA Modification Proteins

iMAP is a large-scale CRISPR perturbation platform based on a germline-transmitted transgene comprising individually floxed, tandemly linked guides that can be inducibly expressed via Cre-mediated recombination. A key limitation was strong recombination bias favoring the proximal guides. Here, we effectively mitigated this bias by inactivating a recombination hotspot, yielding guide representation nearly as uniform as traditional lentiviral libraries. Applying this optimized platform, we systematically profiled 70 (52%) RNA modification factors across 46 mouse tissues, uncovering pervasive tissue-specific essentiality. Notably, iMAP displayed much higher essential gene recovery than prior lentiviral CRISPR screens, attributable to its stronger guide depletion and lower technical noise. Finally, in a tumor model, iMAP identified Thg1l as a repressor of NK cell TNF production; its ortholog knockout enhanced human NK cell-mediated tumor killing, underscoring therapeutic potential. All data are available in an interactive iMAP database. This work advances the Perturbation Atlas, a foundational resource for functional genomics. TeaserA unique CRISPR perturbation tool has been upgraded and deployed to reveal functions of epigenetic regulators in mice.

genomics↗

bioRxiv2024

Environmental and Historical Determinants of African Horse Sickness: Insights from Predictive Modeling

This study marks a pioneering effort in analyzing the global epidemiological patterns of African Horse Sickness (AHS) across different regions. By employing predictive modeling with a comprehensive set of environmental variables, we uncovered overarching global patterns in AHS dynamics, a first in this field. Our analysis revealed significant regional differences influenced by specific climatic conditions, highlighting the diseases complexity. The study also identifies new high-risk areas for AHS, underscoring the necessity for regionally tailored disease management strategies. Despite some limitations, such as the exclusion of wild equine data, this research offers critical insights for global AHS intervention and prevention, setting a path for future research incorporating broader datasets and socio-economic factors. Author SummaryAHS presents a significant challenge to the global equine industry, impacting both health and economic aspects. Our study highlights the profound effect of climate change, particularly the frequency of extreme climatic events including temperature and humidity variations, on the transmission dynamics of diseases like AHS. In our research, we focused on overcoming the challenges associated with identifying key environmental factors and determining the appropriate geographic scale for a comprehensive global understanding of AHS. Our aim was to bridge existing knowledge gaps and elucidate the fundamental principles governing AHS transmission. This study establishes a solid foundation for understanding the intricate dynamics of AHS and offers practical pathways for conservation efforts. It emphasizes the urgent need for environmentally conscious strategies to protect horse populations and the industries dependent on them. By highlighting the relationship between environmental factors, vector presence, and AHS transmission, our research underscores the importance of a holistic approach to disease mitigation. In conclusion, the findings of our study not only contribute to the scientific understanding of AHS but also serve as a guide for policymakers and practitioners in developing effective strategies for disease management and prevention, tailored to the specific environmental conditions and challenges faced in different regions around the world.

ecology↗

bioRxiv2023

Expanding RNA editing toolkit using an IDR-based strategy

RNA base editors should ideally be free of immunogenicity, compact, efficient and specific, which has not been achieved for C>U editing. Here we first describe a compact C>U editor entirely of human origin, created by fusing the human C>U editing enzyme RESCUE-S to CIRTS, a tiny, human-originated programmable RNA binding domain. This editor, CIRTS-RESCUEv1 (V1), was inefficient. Remarkably, a short Histidine-Rich Domain (HRD), which is derived from the Internal Disordered Region (IDR) in the human CYCT1, a protein capable of liquid-liquid phase separation (LLPS), enhanced V1 editing at on-targets as well as off-targets, the latter effect being minor. The V1-HRD fusion protein formed puncta characteristic of LLPS, and various other IDRs (but not an LLPS-impaired mutant) could replace HRD to effectively induce puncta and potentiate V1, suggesting that the diverse domains acted via a common, LLPS-based mechanism. Importantly, the HRD fusion strategy was applicable to various other types of C>U RNA editors. Our study expands the RNA editing toolbox and showcases a general method for stimulating C>U RNA base editors.

molecular biology↗

bioRxiv2023

Single cell transcriptional profiling of benign prostatic hyperplasia reveals a progenitor-like luminal epithelial cell state within an inflammatory microenvironment

Benign prostatic hyperplasia (BPH) is characterized by excessive cell proliferation and inflammation and affects most aging men. The development of new therapies for BPH requires a deeper understanding of the underlying pathophysiology and cellular components of BPH. Here, we characterize at single cell resolution the cellular states of BPH and identify cell populations enriched in BPH that contribute to cell proliferation and inflammation. Single-cell RNA-sequencing was performed on prostate tissue from 15 patients undergoing holmium laser enucleation of the prostate for treatment of BPH. Clustering and differential expression analysis on aligned single cell RNA-seq data was performed to annotate all cell types. Pseudotime, gene set enrichment, gene ontology, and ligand-receptor analyses were performed. 16,234 cells were analyzed and specific stromal, epithelial, and immune subgroups were found to be strongly associated with inflammation. A rare luminal subgroup was identified and pseudotime analysis indicated this luminal subgroup was more closely related to club and basal cells. Using a gene set derived from epithelial stem cells, we found that this luminal subgroup had a significantly higher stem cell signature score than all other epithelial subgroups, suggesting this subgroup is a luminal precursor state. Ligand-receptor interactions between stromal, epithelial, and immune cells were explored with CellPhoneDB. Unique interactions highlighting MIF, a pro-inflammatory cytokine that promotes epithelial cell growth and inflammation in the prostate, were found between fibroblasts and the progenitor luminal subgroup. This luminal subgroup also interacted with neutrophils and macrophages through MIF. Our single-cell profiling of BPH provides a roadmap for inflammation-linked cell subgroups and highlights a novel luminal progenitor subgroup interacting with other cell groups via MIF that may contribute to the inflammation and cell proliferation phenotype associated with BPH.

genomics↗

bioRxiv2023

CZ CELLxGENE Discover: A single-cell data platform for scalable exploration, analysis and modeling of aggregated data

Hundreds of millions of single cells have been analyzed to date using high throughput transcriptomic methods, thanks to technological advances driving the increasingly rapid generation of single-cell data. This provides an exciting opportunity for unlocking new insights into health and disease, made possible by meta-analysis that span diverse datasets building on recent advances in large language models and other machine learning approaches. Despite the promise of these and emerging analytical tools for analyzing large amounts of data, a major challenge remains the sheer number of datasets and inconsistent format, data models and accessibility. Many datasets are available via unique portals platforms that often lack interoperability. Here, we present CZ CellxGene Discover (cellxgene.cziscience.com), a data platform that provides curated and interoperable data. This single-cell data resource, available via a free-to-use online data portal, hosts a growing corpus of community contributed data that spans more than 50 million unique cells. Curated, standardized, and associated with consistent cell-level metadata, this collection of interoperable single-cell transcriptomic data is the largest of its kind. A suite of tools and features enables accessibility and reusability of the data via both computational and visual interfaces to allow researchers to rapidly explore individual datasets and perform cross-corpus analysis. This functionality is enabling meta-analyses of tens of millions of cells across studies and tissues and providing global views of human cells at the resolution of single cells.

cell biology↗

bioRxiv2022

Benzo(a)pyrene regulates chaperone-mediated autophagy via heat shock protein 90

The Benzo(a)pyrene (Bap) exposure induced oxidative damage, DNA damage and autophagy. To explore the molecular mechanism of BaP-induced autophagy. In these studies, we first found that heat shock protein 90 (HSP90), heat shock cognate 70 (HSC70) and lysosomal-associated membrane protein type 2 receptor (Lamp-2a) expressions of C57BL mice lung tissue and A549 cells exposed to BaP were significant increase, as well as Bap induced DNA double-strand breaks (DSBs) and activated DNA damage responses, as evidenced by comet assay and {gamma}-H2AX foci analysis in A549 cells. Our results demonstrated BaP induced CMA and caused DNA damage. Next, we knocked down HSP90 expression by the HSP90 Inhibitor, NVP-AUY 922, exposed or HSP90 shRNA lentivirus transduction in A549 cells. HSC70 and Lamp-2a expressions of these cells exposed to BaP were not significant increase, which showed that BaP inducted CMA was mediated by HSP90. Further, HSP90 shRNA prevented BaP induced of Bap which suggested BaP regulated CMA and caused DNA damage by HSP90. Our results elucidated a new mechanism of BaP regulated CMA through HSP90.

biochemistry↗

bioRxiv2020

Sex-specific predictive values of biomarkers for immunotherapy efficacy in lung adenocarcinoma

It remains a challenge to accurately predict patient responses to tumor immunotherapy, although various biomarkers have been proposed to predict patient responses to anti-PD-1 therapy. Here by integrating genomic, transcriptomic, proteomic and clinical phenotype data from three immunotherapeutic cohorts and a multiple-dimensional dataset of The Cancer Genome Atlas (TCGA) project, we uncovered a profound effect of Sex on the predictive values of conventional biomarkers in lung adenocarcinoma (LUAD): only in females were nonsynonymous mutation burden (TMB), neoantigen burden, smoking signature, KRAS mutations (especially G12C and G12V) or tumor microenvironment robustly correlated with anti-PD-1 efficacy; the correlations in males were either absent or weaker. We propose that Sex be considered in conjunction with conventional biomarkers when predicting immunotherapy efficacy, and conversely, conventional biomarkers be carefully controlled for when attempting to dissect the impact of Sex on immunotherapy efficacy.

cancer biology↗

bioRxiv2020

Novel mosaic mice with diverse applications

Gene-deficient mouse models are indispensable for interrogating mammalian gene functions, but the conventional models allow the study of only one or few genes per mouse line, which has been a bottleneck in functional genomics. To confront the challenge, we have combined the CRISPR-Cas and Cre-Lox systems to develop a novel type of mosaic mice termed MARC (Mosaic Animal based on gRNA and Cre) for targeting many genes per mouse but only one gene per cell. This technology employs a transgene comprising a modified U6 promoter upstream of a series of floxed gRNA genes linked together in tandem, with one gRNA expressed per cell following Cre-mediated recombination. At least 61 gRNA genes can be stably maintained in the transgene, and importantly, enables robust proof-of-principle in vivo screens, demonstrating the potential for quickly evaluating the functions of many genes in diverse tissues in a single MARC line. In theory, MARC can also be analyzed by single-cell sequencing, and should enable cost-effective derivation of conventional single-gene-KO lines via simple breeding. Our study establishes MARC as an important addition to the mouse genetics toolbox.

genetics↗

bioRxiv2019

Sex-based mutational landscape confers sensitivity to checkpoint blockade immunotherapy in cutaneous melanoma

Anti-programmed cell death protein 1 (PD-1) therapy provided superior benefits in skin cutaneous melanoma (SKCM), but only a minority of patients responded. As SKCM had sex-based immunological differences, we sought to explore the potential interactions between sex and clinical responses to anti-PD-1 therapy in SKCM. We found that sex had significant effects on anti-PD-1 therapy. Tumor mutation burden (TMB) and neoantigen burden significantly correlated with the clinical responses to anti-PD-1 therapy only in males. Meanwhile, we recruited The Cancer Genome Atlas (TCGA) database to explore sex-based differences of the tumor microenvironment (TME) in SKCM. We observed that males with high TMB, especially in conjunction with interferon-gamma (IFN-{gamma}) signaling, significantly correlated with increased PD-L1 expression, major histocompatibility complex (MHC) class I gene expression, and the infiltration of cytotoxic T lymphocytes (CTLs). In addition, TMB and anti-PD-1 efficacy in SKCM each correlated with homologous recombination repair (HRR) gene BRCA2 mutations, but only in males. Taken together, these data revealed that in SKCM, high TMB correlated with prominent immunotherapeutic TME only in males, and that gender should be taken into account when predicting the efficacy of anti-PD-1 therapy for SKCM.

immunology↗

bioRxiv2018

A conserved role of the insulin-like signaling pathway in uric acid pathologies revealed in Drosophila melanogaster

Elevated uric acid (UA) is a key factor for disorders, including gout or kidney stones and result from abrogated expression of Urate Oxidase (Uro) and diet. To understand the genetic pathways influencing UA metabolism we established a Drosophila melanogaster model with elevated UA using Uro knockdown. Reduced Uro expression resulted in the accumulation of UA concretions and diet-dependent shortening of lifespan. Inhibition of insulin-like signaling (ILS) pathway genes reduced UA and concretion load. In humans, SNPs in the ILS genes AKT2 and FOXO3 were associated with UA levels or gout, supporting a conserved role for ILS in modulating UA metabolism. Downstream of the ILS pathway UA pathogenicity was mediated partly by NADPH Oxidase, whose inhibition attenuated the reduced lifespan and concretion accumulation. Thus, genes in the ILS pathway represent potential therapeutic targets for treating UA associated pathologies, including gout and kidney stones.\n\nHighlightsO_LIIn Drosophila high uric acid (UA) levels shorten lifespan and cause UA aggregation\nC_LIO_LIConserved in flies and humans, the ILS pathway associates with UA pathologies\nC_LIO_LIFoxO dampens concretion formation by reducing UA levels and ROS formation\nC_LIO_LIInhibition of NOX alleviates the lifespan attenuation and UA aggregation\nC_LI

pathology↗