Biology subjects

Lei, Y. L.

Publications and source records attributed to Lei, Y. L..

7 recordsLinked to original sources

bioRxiv2025

Impact of Absent in Melanoma 2 (AIM2) on Antigen-Specific CD4+ T cell Activation and Homeostasis.

The intrinsic role of Absent in Melanoma 2 (AIM2) in CD4+ T cells during antigen-specific activation and differentiation is not fully understood. To address this, we crossed AIM2-deficient mice with OT-II/RAG transgenic mice, which express an ovalbumin-specific T cell receptor in CD4+ T cells (OT-II). We found that AIM2 does not regulate thymic selection of CD4+ thymocytes, but may promote trafficking or survivability of CD4+ T cells in the spleen. In vitro coculture assays revealed that Aim2-/- OT-II CD4+ T cells produce significantly less IL-2 than wild type OT-II CD4+ T cells when cocultured with ovalbumin-incubated dendritic cells. However, we found no differences in CD4+ T cell proliferative capacity and differentiation among WT OT-II and Aim2-/- OT-II CD4+ T cells following OVA immunization in vivo. Finally, adoptively transferred WT and Aim2-/- OT-II cells controlled the growth of implanted OVA-expressing NOOC2 syngeneic tumors at an equal capacity. Taken together, these results indicate that AIM2 contributes to CD4+ T cell homeostasis in secondary lymphoid organs in vivo. AIM2 also intrinsically promotes IL-2 production in response to antigen-specific activation in vitro. However, this loss of IL-2 does not translate to measurable defects in proliferative, differentiation or effector function during OVA immunization or tumor challenge in vivo.

immunology↗

bioRxiv2025

Immune phenotype-guided identification of disease-associated pathobionts in Crohn's disease

Aberrant immune activation within the gut mucosa and gut dysbiosis have been implicated in the pathogenesis of Crohns disease (CD). However, the specific immune responses triggered by dysbiotic microbiota, as well as the bacteria responsible for this activation, remain incompletely understood. Here, using the human microbiota-associated (HMA) mouse system, we demonstrated that colonization with dysbiotic gut microbiota from CD patients specifically induces the accumulation of mononuclear phagocytes, which may drive an interleukin-1 (IL-1)-driven inflammatory signature. Moreover, we identified pathobiont strains with a potent IL-1{beta}-inducing capacity, termed IL-1{beta}-inducing pathobionts (IBIP). Isolated IBIP strains exhibit genetic and functional similarities to adherent-invasive Escherichia coli but harbor unique virulence-associated genes. Colonization with the IBIP E. coli strain exacerbated experimental colitis in an IL-1 signal-dependent manner. Notably, the colonization of IBIP E. coli can be detected by measuring the levels of specific immunoglobulin A (IgA) in their stool samples. Moreover, the level of IBIP-reactive IgA in stool may serve as a predictive biomarker for treatment response to anti-TNF therapies in treatment-naive pediatric CD patients. Altogether, IBIP colonization could help identify CD patients with inflammatory dysbiosis who are likely to be refractory to anti-TNF therapies.

immunology↗

bioRxiv2024

SOX2-induced IL-1alpha-mediated immune suppression drives epithelial dysplasia malignant transformation

Squamous cell carcinomas (SCC) are often preceded by potentially malignant precursor lesions, most of which remain benign. The terminal exhaustion phenotypes of effector T-cells and the accumulation of myeloid-derived suppressor cells (MDSC) have been thoroughly characterized in established SCC. However, it is unclear what precancerous lesions harbor a bona fide high risk for malignant transformation and how precancerous epithelial dysplasia drives the immune system to the point of no return. Here we show that expression of SRY-box transcription factor 2 (SOX2) in precancerous lesions imparts an irreversible risk that recruits suppressive myeloid cells by promoting the release of CCL2. We developed a unique genetically engineered mouse model (GEMM) to recapitulate the malignant transformation of epithelial dysplasia to SCC in the oral mucosa with high histologic and phenotypic fidelity. Using a combination of longitudinal human specimens and the Sox2-GEMM, we found that the myeloid cells in precancerous epithelial dysplasia exhibit a distinctive dichotomous profile featuring high levels of IL-1-SLC2A1 and low levels of type-I interferon (IFN-I) signatures, which occurs before SCC emerges histologically. Brief priming of myeloid cells with IL-1 desensitizes them to IFN-I agonists and makes myeloid-derived suppressor cells (MDSC) even more suppressive of T-cell activation. Mechanistically, IL-1 activation represses the expression of DHHC3/7 enzymes, which are responsible for the palmitoylation of stimulator of interferon genes (STING). Early blockade of IL1 signaling using pharmacologic and genetic approaches similarly reduces MDSC and SLC2A1high myeloid cells, suppresses epithelial dysplasia transformation, and extends survival. This work establishes a previously unrecognized SOX2-CCL2-IL1 pathway that leads to irreversible immune escape when precancerous epithelial lesions transform.

cancer biology↗

bioRxiv2023

MEM-GAN: A Pseudo Membrane Generator for Single-cell Imaging in Fluorescent Microscopy

Fluorescent microscopy imaging is vital to capturing single-cell spatial data, characterizing tissue organization and facilitating comprehensive analysis of cellular state. Advancements in fluorescent microscopy imaging technologies have enabled precise downstream cellular analysis, particularly in cell segmentation. Accurate segmentation of individual cells allows better profiling and understanding of cell properties and behaviors. The majority of existing segmentation methods predominantly concentrate on enhancing segmentation algorithms, and their effectiveness strongly relies on the input stained image quality. Factors such as high cellular density, indistinct cell boundaries, and staining artifacts can result in uneven and low-quality staining, particularly causing missing or unclear membrane staining. These artifacts adversely impact the efficacy of the subsequent cell segmentation methods. To tackle this insufficient membrane staining, we propose a novel approach, MO_SCPLOWEMC_SCPLOW-GAN, to generate high-quality membranes for cells with missing or weak membranes. Inspired by advanced style transfer techniques in computer vision, MO_SCPLOWEMC_SCPLOW-GAN styles the content of the cells with missing or weak membranes into cells with integrated membrane staining. Considering the differences in membrane morphology between epithelial/tumor cells and immune cells, MO_SCPLOWEMC_SCPLOW-GAN deals with tumor and immune cells separately, not only enhancing membrane staining for cells with partially weak membrane signals but also generating membranes for cells with only nuclear channels. The proposed MO_SCPLOWEMC_SCPLOW-GAN is evaluated using the publicly available CosMx dataset. Experimental results demonstrate significant improvements in image staining quality, more accurate representation of membrane morphology characteristics, and better performance in downstream segmentation tasks. MO_SCPLOWEMC_SCPLOW-GAN is flexibly adapted and applied to other spatially resolved transcriptomics datasets, such as MERFISH and FISHseq. Our work provides a new perspective on tackling the challenges in cell segmentation from fluorescent microscopy image restoration. The implementation of MO_SCPLOWEMC_SCPLOW-GAN is open-source and available at the github repository https://github.com/OmicsML/Mem-GAN. The interactive webserver-based demo of MO_SCPLOWEMC_SCPLOW-GAN can be accessed at http://omicsml.ai/memgan.

bioinformatics↗

bioRxiv2021

OXPHOS Promotes Apoptotic Resistance and Persistence in TH17 cells

Apoptotic cell death is a cell-intrinsic, immune tolerance mechanism that regulates the magnitude and resolution of T cell-mediated responses. Evasion of apoptosis is critical for the generation of memory T cells, as well as autoimmune T cells, and knowledge of the mechanisms that enable resistance to apoptosis will provide insight into ways to modulate their activity during protective and pathogenic responses. IL-17-producing CD4 T cells (TH17s) are long-lived, memory cells. These features enable their role in host defense, chronic inflammatory disorders, and anti-tumor immunity. A growing number of reports now indicate that TH17s in vivo require mitochondrial oxidative phosphorylation (OXPHOS), a metabolic phenotype that is poorly induced in vitro. To elucidate the role of OXPHOS in TH17 processes, we developed a system to polarize TH17s that metabolically resembled their in vivo counterparts. We discovered that directing TH17s to use OXPHOS promotes mitochondrial fitness, glutamine anaplerosis, and an anti-apoptotic phenotype marked by high BCL-XL and low BIM. Through competitive co-transfer experiments and tumor studies, we further revealed how OXPHOS protects TH17s from cell death while enhancing their persistence in the periphery and tumor microenvironment. Together, our work demonstrates a non-classical role of metabolism in regulating TH17 cell fate and highlights the potential for therapies that target OXPHOS in TH17-driven diseases.

immunology↗

bioRxiv2021

Supervised Capacity Preserving Mapping: A Clustering Guided Visualization Method for scRNAseq data

The rapid development of scRNA-seq technologies enables us to explore the transcriptome at the cell level in a large scale. Recently, various computational methods have been developed to analyze the scR-NAseq data such as clustering and visualization. However, current visualization methods including t-SNE and UMAP are challenged by the limited accuracy of rendering the geometic relationship of populations with distinct functional states. Most visualization methods are unsupervised, leaving out information from the clustering results or given labels. This leads to the inaccurate depiction of the distances between the bona fide functional states and the variance of clusters. We present supCPM, a robust supervised visualization method, which separates different clusters, preserves global structure, and tracks the cluster variance. Compared with six visualization methods using synthetic and real data sets, supCPM shows improved performance than other methods in preserving the global geometric structure and data variance. Overall, supCPM provides an enhanced visualization pipeline to assist the interpretation of functional transition and accurately depict population segregation.

bioinformatics↗

bioRxiv2018

Fast and Robust Deconvolution of Tumor Infiltrating Lymphocyte from Expression Profiles using Least Trimmed Squares

Gene-expression deconvolution is used to quantify different types of cells in a mixed population. It provides a highly promising solution to rapidly characterize the tumor-infiltrating immune landscape and identify cold cancers. However, a major challenge is that gene-expression data are frequently contaminated by many outliers that decrease the estimation accuracy. Thus, it is imperative to develop a robust deconvolution method that automatically decontaminates data by reliably detecting and removing outliers. We developed a new machine learning tool, Fast And Robust DEconvolution of Expression Profiles (FARDEEP), to enumerate immune cell subsets from whole tumor tissue samples. To reduce noise in the tumor gene expression datasets, FARDEEP utilizes an adaptive least trimmed square to automatically detect and remove outliers before estimating the cell compositions. We show that FARDEEP is less susceptible to outliers and returns a better estimation of coefficients than the existing methods with both numerical simulations and real datasets. FARDEEP provides the absolute quantitation of each immune cell subset in addition to relative percentages. Hence, FARDEEP represents a novel robust algorithm to complement the existing toolkit for the characterization of tissue-infiltrating immune cell landscape. The source code for FARDEEP as implemented in R is available for download at https://goo.gl/SqGKuo.

bioinformatics↗