Biology subjects

Shi, T.

Publications and source records attributed to Shi, T..

At least 37 records · Page 2Linked to original sources

bioRxiv2024

Cholestasis alters polarization and suppressor function of hepatic regulatory T cells.

Fibrosing cholangiopathies, including biliary atresia and primary sclerosing cholangitis, involve immune-mediated bile duct epithelial injury and hepatic bile acid (BA) retention (cholestasis). Regulatory T-cells (Tregs) can prevent auto-reactive lymphocyte activation, yet the effects of BA on this CD4 lymphocyte subset are unknown. Gene regulatory networks for hepatic CD4 lymphocytes in a murine cholestasis model revealed Tregs are polarized to Th17 during cholestasis. Following bile duct ligation, Stat3 deletion in CD4 lymphocytes preserved hepatic Treg responses. While pharmacological reduction of hepatic BA in MDR2-/- mice prompted Treg expansion and diminished liver injury, this improvement subsided with Treg depletion. A cluster of patients diagnosed with biliary atresia showed both increased hepatic Treg responses and improved 2-year native liver survival, supporting that Tregs might protect against neonatal bile duct obstruction. Together, these findings suggest liver BA determine Treg function and should be considered as a therapeutic target to restore protective hepatic immune responses.

immunology↗

bioRxiv2024

Gucy1α1 specifically marks kidney, heart, lung and liver fibroblasts

Fibrosis is a common outcome of numerous pathologies, including chronic kidney disease (CKD), a progressive renal function deterioration. Current approaches to target activated fibroblasts, key effector contributors to fibrotic tissue remodeling, lack specificity. Here, we report Gucy11 as a specific kidney fibroblast marker. Gucy11 levels significantly increased over the course of two clinically relevant murine CKD models and directly correlated with established fibrosis markers. Immunofluorescent (IF) imaging showed that Gucy11 comprehensively labelled cortical and medullary quiescent and activated fibroblasts in the control kidney and throughout injury progression, respectively. Unlike traditionally used markers platelet derived growth factor receptor beta (Pdgfr{beta}) and vimentin (Vim), Gucy11 did not overlap with off-target populations such as podocytes. Notably, Gucy11 labelled kidney fibroblasts in both male and female mice. Furthermore, we observed elevated GUCY11 expression in the human fibrotic kidney and lung. Studies in the murine models of cardiac and liver fibrosis revealed Gucy11 elevation in activated Pdgfr{beta}-, Vim- and alpha smooth muscle actin (Sma)-expressing fibroblasts paralleling injury progression and resolution. Overall, we demonstrate Gucy11 as an exclusive fibroblast marker in both sexes. Due to its multiorgan translational potential, GUCY11 might provide a novel promising strategy to specifically target and mechanistically examine fibroblasts.

molecular biology↗

bioRxiv2024

A Mem-dELISA platform for dual color and ultrasensitive digital detection of colocalized proteins on extracellular vesicles

Accurate, multiplex, and ultrasensitive measurement of different colocalized protein markers on individual tumor-derived extracellular vesicles (EVs) and dimerized proteins with multiple epitopes could provide insights into cancer heterogeneity, therapy management and early diagnostics that cannot be extracted from bulk methods. However, current digital protein assays lack certain features to enable robust colocalization, including multi-color detection capability, large dynamic range, and selectivity against background proteins. Here, we report a lithography-free, inexpensive (< $0.1) and ultrasensitive dual-color Membrane Digital ELISA (Mem-dELISA) platform by using track-etched polycarbonate (PCTE) membranes to overcome these shortcomings. Their through-pores remove air bubbles through wicking before they are sealed on one side by adhesion to form microwells. Immunomagnetic bead-analyte complexes and substrate solution are then loaded into the microwells from the opposite side, with >80% loading efficiency, before sealing with oil. This enables duplex digital protein colorimetric assay with beta galactosidase and alkaline phosphatase enzymes. The platform achieves 5 logs of dynamic range with a limit of detection of 10 aM for both Biotinylated {beta}-galactosidase (B-{beta}G) and Biotin Alkaline Phosphatase Conjugated (B-ALP) proteins. We demonstrate its potential by showing that a higher dosage of paclitaxel suppresses EpCAM-positive EVs but not GPC-1 positive EVs from breast cancer cells, a decline in chemo-resistance that cannot be detected with Western blot analysis of cell lysate. The Mem-dELISA is poised to empower researchers to conduct ultrasensitive, high throughput protein colocalization studies for disease diagnostics, treatment monitoring and biomarker discovery.

cancer biology↗

bioRxiv2024

Unveiling the Intricate Sinking behavior of Large Diatoms: Insights from Time-Frequency Analysis of Palmerina hardmaniana Sinking under Silicate-Depleted Conditions

Nutrient limits impact diatom sinking in time domain, but response in time-frequency domain is unclear. Studying the response of large diatoms to nutrients exclusively in the time domain fails to fully capture the complete impact of nutrient limitations on sinking behavior due to the absence of crucial information, including period and frequency. Wavelet analysis provides valuable insights into the period and frequency of signals and unveils their positions in the time. This study investigated the sinking behavior response of the large diatom Palmerina hardmaniana to silicate-depleted conditions in the time-frequency domain using wavelet analysis. The results showed that P. hardmaniana was capable of regulating its sinking speed, and this regulation occurred intermittently in time. The predominant frequency of intermittent regulation fell within the range of 0.13-0.50 Hz (equivalent to a period of 2-8 s) for both control and silicate-depleted conditions. The similarity in the frequency range of regulation between the two groups suggests the involvement of shared physiological mechanisms. P. hardmaniana responded to silicate depletion by intensifying the regulation of 0.13-0.50 Hz, which was reflected in the time domain as a change in the proportion of different instantaneous sinking speeds and consequently lead to a significant increase or decrease in the mean sinking speed (p<0.05). Additionally, the regulation of P. hardmaniana sinking behavior was also influenced by the physiological state of the cells. Short-term silicate stress (30 min) enhanced the oscillation power of sinking regulation, while prolonged silicate stress ([≥] 3 d) led to a decline in oscillation power.

plant biology↗

bioRxiv2024

A fast and sensitive size-exclusion chromatography method for plasma extracellular vesicle proteomic analysis

Extracellular vesicles (EVs) carry diverse biomolecules derived from their parental cells, making their components excellent biomarker candidates. However, purifying EVs is a major hurdle in biomarker discovery since current methods require large amounts of samples, are time-consuming and typically have poor reproducibility. Here we describe a simple, fast, and sensitive EV fractionation method using size exclusion chromatography (SEC) on a fast protein liquid chromatography (FPLC) system. Our method uses a Superose 6 Increase 5/150, which has a bed volume of 2.9 mL. The FPLC system and small column size enable reproducible separation of only 50 {micro}L of human plasma in 15 minutes. To demonstrate the utility of our method, we used longitudinal samples from a group of individuals that underwent intense exercise. A total of 838 proteins were identified, of which, 261 were previously characterized as EV proteins, including classical markers, such as cluster of differentiation (CD)9 and CD81. Quantitative analysis showed low technical variability with correlation coefficients greater than 0.9 between replicates. The analysis captured differences in relevant EV-proteins involved in response to physical activity. Our method enables fast and sensitive fractionation of plasma EVs with low variability, which will facilitate biomarker studies in large clinical cohorts.

biochemistry↗

bioRxiv2023

Camel milk affects serum metabolites by modulating the intestinal microflora

Gut microbes play a vital role in human health and are influenced by numerous factors including diet, genetics, and environment. (Fermented) Camel milk, which is abundant in nutrients and lacks allergenic proteins, has been consumed for its edible and medicinal properties for centuries. Research on camel milks impact on gut microbiota and host metabolism is still limited. The results found that sour camel milk contained various beneficial bacteria such as Lactobacillus helveticus, Acinetobacter lwoffii, Eubacterium coprostanoligenes group, Lachnospiraceae, which could be transported to the recipients intestines by diet. This study specified that the transportation of microbiome happened both intra- and inter-species and played a principal role in the formation of progeny gut microflora. An investigation on type 2 diabetic rats revealed that the composition of gut microflora and serum metabolites of those fed with high-dose camel whey was closer to that of the normal. Eubacterium limnetica, which can reduce the risk of diseases by producing MtcB protein, was found in the gut microflora of the ones taking camel milk. These results evidenced the high potential of camel milk as a functional food.

microbiology↗

bioRxiv2023

Sex specific regulation of the cortical transcriptome in response to sleep deprivation

Multiple studies have documented sex differences in sleep behaviour, however the molecular determinants of such differences remain unknown. Furthermore, most studies addressing molecular mechanisms have been performed only in males, leaving the current state of knowledge biased towards the male sex. To address this, we studied the differences in the transcriptome of the cerebral cortex of male and female C57Bl/6J mice after six hours of sleep deprivation. We found that several genes, including the neurotrophin growth factor Bdnf, immediate early genes Fosb and Fosl2, and the adenylate cyclase Adcy7 are differentially upregulated in males compared to females. We identified the androgen-receptor activating transcription factor EZH2 as the upstream regulatory element specifying sex differences in the sleep deprivation transcriptome. We propose that the pathways downstream of these transcripts, which impact on cellular re-organisation, synaptic signalling and learning may underpin the differential response to sleep deprivation in the two sexes.

molecular biology↗

bioRxiv2023

Sample-efficient Antibody Design through Protein Language Model for Risk-aware Batch Bayesian Optimization

Antibody design is a time-consuming and expensive process that often requires extensive experimentation to identify the best candidates. To address this challenge, we propose an efficient and risk-aware antibody design framework that leverages protein language models (PLMs) and batch Bayesian optimization (BO). Our framework utilizes the generative power of protein language models to predict candidate sequences with higher naturalness and a Bayesian optimization algorithm to iteratively explore the sequence space and identify the most promising candidates. To further improve the efficiency of the search process, we introduce a risk-aware approach that balances exploration and exploitation by incorporating uncertainty estimates into the acquisition function of the Bayesian optimization algorithm. We demonstrate the effectiveness of our approach through experiments on several benchmark datasets, showing that our framework outperforms state-of-the-art methods in terms of both efficiency and quality of the designed sequences. Our framework has the potential to accelerate the discovery of new antibodies and reduce the cost and time required for antibody design.

bioinformatics↗

bioRxiv2023

Robust collection and processing for label-free single voxel proteomics

With advanced mass spectrometry (MS)-based proteomics, genome-scale proteome coverage can be achieved from bulk tissues. However, such bulk measurement lacks spatial resolution and obscures important tissue heterogeneity, which make it impossible for proteome mapping of tissue microenvironment. Here we report an integrated wet collection of single tissue voxel and Surfactant-assisted One-Pot voxel processing method termed wcSOP for robust label-free single voxel proteomics. wcSOP capitalizes on buffer droplet-assisted wet collection of single tissue voxel dissected by LCM into the PCR tube cap and MS-compatible surfactant-assisted one-pot voxel processing in the collection cap. This convenient method allows reproducible label-free quantification of [~]900 and [~]4,600 proteins for single voxel from fresh frozen human spleen tissue at 20 m x 20 m x 10 m (close to single cells) and 200 m x 200 m x 10 m ([~]100 cells), respectively. 100s-1000s of protein signatures with differential expression levels were identified to be spatially resolved between spleen red and white pulp regions depending on the voxel size. Region-specific signaling pathways were enriched from single voxel proteomics data. Antibody-based CODEX imaging was used to validate label-free MS quantitation for single voxel analysis. The wcSOP-MS method paves the way for routine robust single voxel proteomics and spatial proteomics.

molecular biology↗

bioRxiv2023

Transmission bottleneck size estimation from de novo viral genetic variation

Sequencing of viral infections has become increasingly common over the last decade. Deep sequencing data in particular have proven useful in characterizing the roles that genetic drift and natural selection play in shaping within-host viral populations. They have also been used to estimate transmission bottleneck sizes from identified donor-recipient pairs. These bottleneck sizes quantify the number of viral particles that establish genetic lineages in the recipient host and are important to estimate due to their impact on viral evolution. Current approaches for estimating bottleneck sizes exclusively consider the subset of viral sites that are observed as polymorphic in the donor individual. However, allele frequencies can change dramatically over the course of an individuals infection, such that sites that are polymorphic in the donor at the time of transmission may not be polymorphic in the donor at the time of sampling and allele frequencies at donor-polymorphic sites may change dramatically over the course of a recipients infection. Because of this, transmission bottleneck sizes estimated using allele frequencies observed at a donors polymorphic sites may be considerable underestimates of true bottleneck sizes. Here, we present a new statistical approach for instead estimating bottleneck sizes using patterns of viral genetic variation that arose de novo within a recipient individual. Specifically, our approach makes use of the number of clonal viral variants observed in a transmission pair, defined as the number of viral sites that are monomorphic in both the donor and the recipient but carry different alleles. We first test our approach on a simulated dataset and then apply it to both influenza A virus sequence data and SARS-CoV-2 sequence data from identified transmission pairs. Our results confirm the existence of extremely tight transmission bottlenecks for these two respiratory viruses, using an approach that does not tend to underestimate transmission bottleneck sizes.

evolutionary biology↗

bioRxiv2023

Anti-PD-1-iRGD Peptide Conjugate Boosts Antitumor Efficacy via Engagement Augmentation and Penetration Enhancement of T cells

Despite the important breakthroughs of immune-checkpoint inhibitors (ICIs) in recent years, the overall objective response rate (ORR) remains limited in various cancers. Here, we synthesized programmed cell death protein-1 (PD-1) antibody iRGD conjugate (PD-1-(iRGD)2) through glycoengineering and bio-orthogonal reaction. PD-1-(iRGD)2 exhibited extra iRGD receptor dependent affinity to several cancer cell lines rather than normal cell lines. Via dual targeting, PD-1-(iRGD)2 engageed tumor cells and T cells thus mediating T cell activation and facilitating tumor elimination. Besides, the attachment of iRGD impressively improved the penetrability of both PD-1 antibody and PD-1+ T cells. In multiple syngeneic mouse models, PD-1-(iRGD)2 effectively reduced tumor growth with satisfactory biosafety. Moreover, results of flow cytometry and single-cell RNA-seq revealed that PD-1-(iRGD)2 remodeled the tumor microenvironment (TME) and expanded a unique population of "better effector" CD8+ tumor infiltrating T cells (TILs) expressing stem and memory associated genes including Tcf7, Il7r, Lef1 and Bach2. Conclusively, PD-1-(iRGD)2 could be a novel and promising therapeutic approach for cancer immunotherapy. Statement of significanceDesigned against the clinical dilemma of unsatisfied response rate after contemporary cancer immunotherapy, PD-1-(iRGD)2 engages T cells and tumor cells, promotes T cell infiltration and expands a unique population of "better effectors" with enhanced therapeutic potential for the treatment of cancer.

immunology↗

bioRxiv2023

The super-pangenome of Populus unveil genomic facets for adaptation and diversification in widespread forest trees

Understanding the underlying mechanisms between genome evolution and phenotypic and adaptive innovations is a key goal of evolutionary studies. Poplars are the worlds most widely distributed and cultivated trees, with extensive phenotypic diversity and environmental adaptability. Here we report a genus-level super-pangenome of 19 Populus genomes. After integrating pan-genomes with transcriptomes, methylomes and chromatin accessibility mapping, we reveal that the evolutionary fate of pan-genes and duplicated genes are largely associated with local genomic landscapes of regulatory and epigenetic architectures. Further comparative genomic analyses enabled to identify 142,202 structural variations (SVs) across species, which overlap with substantial genes and play key roles in both phenotypic and adaptive divergence. We experimentally validated a [~]180 bp presence/absence variant located in the promoter of the CUC2 gene, which contributed critically to leaf serration divergence between species. Together, this first super-pangenome resource in forest trees will not only accelerate molecular functional studies and genetic breeding of this globally important tree genus, but also lays a foundation for our understanding of tree biology.

evolutionary biology↗

bioRxiv2023

Chromosomal-level genome assembly of Populus lasiocarpa

Despite widespread biodiversity loss, our understanding of how species and populations will respond to accelerated climate change remains limited. In this study, we predict the evolutionary responses of Populus lasiocarpa, a key alpine forest tree species primarily found in the mountainous regions of a global biodiversity hotspot, to climate change. We accomplish this by generating and integrating a new reference genome for P. lasiocarpa, re-sequencing data for 200 samples, and gene expression profiles for leaf and root tissue following exposure to heat and waterlogging. Analyses of the re-sequencing data indicate that demographic dynamics, divergent selection, and long-term balancing selection have shaped and maintained genetic variation within and between populations over historical timescales. In examining genomic signatures of contemporary climate adaptation, we found that haplotype blocks, characterized by inversion polymorphisms that suppress recombination, play a crucial role in clustering environmentally adaptive variations. Comparison of evolved and plastic gene expression show that genes with expression plasticity generally align with evolved responses, highlighting the adaptive role of plasticity. Lastly, we incorporated local adaptation, migration, genetic load, and plasticity responses into our predictions of population-level climate change risks. Our findings reveal that western populations, primarily distributed in the Hengduan Mountains--a region known for its environmental heterogeneity and significant biodiversity--are the most vulnerable to climate change and should be prioritized for conservation and management. Overall, our study advances understanding of the relative roles of long-term natural selection, local environmental adaptation, and immediate plasticity responses in driving evolutionary adaptation to climate change in keystone species.

genomics↗

bioRxiv2023

Chromosomal-level genome assembly of Populus adenopoda

High-quality reference genomes for several species have promoted breeding and functional studies of poplar trees. By resequencing numerous accessions of these and closely related species, single nucleotide polymorphisms (SNPs) and small insertion/deletions (InDels) have been identified to assist in clarifying local adaptation and phenotypic diversification. A chromosome-level genome assembly for P. adenopoda was assembled based on Illumina and PacBio sequencing platforms, facilitated by Hi-C technology. The assembled genome size was about 383 Mb, with 99.70% of the contigs anchored to 19 pseudo-chromosomes, and a total of 33,505 protein-coding genes were annotated. This high-quality genome provided the genomic basis for the subsequent detection of various variants.

genomics↗

bioRxiv2023

Chromosomal-level genome assembly of Populus davidiana

Despite the population structure and genetic differentiation of P. davidiana has been reported, little is known about the P. davidiana genome characterization with the genomes assembled at the chromosome level. As one of the most widely distributed and ecologically important tree species in China, P. davidiana is an excellent resource to understand population adaption to climate and environment change. Here we present a high-quality assembly based on long-read sequences and Hi-C data. This assembly is assembled into 19 contiguous chromosomes which provides a powerful tool for future association studies.

genomics↗

bioRxiv2023

Computational ranking-assisted identification of Plexin-B2 in homotypic and heterotypic clustering of circulating tumor cells in breast cancer metastasis

Metastasis is the cause of over 90% of all deaths associated with breast cancer, yet the strategies to predict cancer spreading based on primary tumor profiles and therefore prevent metastasis are egregiously limited. As rare precursor cells to metastasis, circulating tumor cells (CTCs) in multicellular clusters in the blood are 20-50 times more likely to produce viable metastasis than single CTCs. However, the molecular mechanisms underlying various CTC clusters, such as homotypic tumor cell clusters and heterotypic tumor-immune cell clusters, are yet to be fully elucidated. Combining machine learning-assisted computational ranking with experimental demonstration to assess cell adhesion candidates, we identified a transmembrane protein Plexin- B2 (PB2) as a new therapeutic target that drives the formation of both homotypic and heterotypic CTC clusters. High PB2 expression in human primary tumors predicts an unfavorable distant metastasis-free survival and is enriched in CTC clusters compared to single CTCs in advanced breast cancers. Loss of PB2 reduces formation of homotypic tumor cell clusters as well as heterotypic tumor-myeloid cell clusters in triple-negative breast cancer. Interactions between PB2 and its ligand Sema4C on tumor cells promote homotypic cluster formation, and PB2 binding with Sema4A on myeloid cells (monocytes) drives heterotypic CTC cluster formation, suggesting that metastasizing tumor cells hijack the PB2/Sema family axis to promote lung metastasis in breast cancer. Additionally, using a global proteomic analysis, we identified novel downstream effectors of the PB2 pathway associated with cancer stemness, cell cycling, and tumor cell clustering in breast cancer. Thus, PB2 is a novel therapeutic target for preventing new metastasis.

cancer biology↗

bioRxiv2023

Phosphorylation barcodes direct biased chemokine signaling at CXCR3

G protein-coupled receptor (GPCR) biased agonism, the activation of some signaling pathways over others, is thought to largely be due to differential receptor phosphorylation, or "phosphorylation barcodes." At chemokine receptors, ligands act as "biased agonists" with complex signaling profiles, which contributes to the limited success in pharmacologically targeting these receptors. Here, mass spectrometry-based global phosphoproteomics revealed that CXCR3 chemokines generate different phosphorylation barcodes associated with differential transducer activation. Chemokine stimulation resulted in distinct changes throughout the kinome in global phosphoproteomic studies. Mutation of CXCR3 phosphosites altered {beta}-arrestin conformation in cellular assays and was confirmed by molecular dynamics simulations. T cells expressing phosphorylation-deficient CXCR3 mutants resulted in agonist- and receptor-specific chemotactic profiles. Our results demonstrate that CXCR3 chemokines are non-redundant and act as biased agonists through differential encoding of phosphorylation barcodes and lead to distinct physiological processes.

biochemistry↗

bioRxiv2023

Single cell transcriptomic analysis of renal allograft rejection reveals novel insights into intragraft TCR clonality

Bulk analysis of renal allograft biopsies (rBx) identified RNA transcripts associated with acute cellular rejection (ACR); however, these lacked cellular context critical to mechanistic understanding. We performed combined single cell RNA transcriptomic and TCR/{beta} sequencing on rBx from patients with ACR under differing immunosuppression (IS): tacrolimus, iscalimab, and belatacept. TCR analysis revealed a highly restricted CD8+ T cell clonal expansion (CD8EXP), independent of HLA mismatch or IS type. Subcloning of TCR/{beta} cDNAs from CD8EXP into Jurkat76 cells (TCR-/-) conferred alloreactivity by mixed lymphocyte reaction. scRNAseq analysis of CD8EXP revealed effector, memory, and exhausted phenotypes that were influenced by IS type. Successful anti-rejection treatment decreased, but did not eliminate, CD8EXP, while CD8EXP were maintained during treatment-refractory rejection. Finally, most rBx-derived CD8EXP were also observed in matching urine samples. Overall, our data define the clonal CD8+ T cell response to ACR, providing novel insights to improve detection, assessment, and treatment of rejection.

immunology↗