Biology subjects

Fu, S.

Publications and source records attributed to Fu, S..

At least 55 records · Page 3Linked to original sources

bioRxiv2024

Single-cell transcriptomics reveals immunosuppressive microenvironment and highlights stumor-promoting macrophage cells in Glioblastoma

Glioblastoma (GBM) is the most prevalent and aggressive primary brain malignancy in adults. Nevertheless, the cellular heterogeneity and complexity within the GBM microenvironment (TME) are still not fully understood, posing a significant obstacle in the advancement of more efficient immunotherapies for GBM. In this study, we conducted an integrated analysis of 48 tumor fragments from 24 GBM patients at the single-cell level, uncovering substantial molecular diversity within immune infiltrates. We characterized molecular signatures for five distinct tumor-associated macrophage (TAM) subtypes. Notably, the TAM_MRC1 subtype displayed a pronounced M2 polarization signature. Additionally, we identified a subtype of natural killer (NK) cells, designated CD56dim_DNAJB1. This subtype is characterized by an exhausted phenotype, evidenced by an elevated stress signature and enrichment in the PD-L1/PD-1 checkpoint pathway. Our findings also highlight significant cell-cell interactions among malignant glioma cells, TAM, and NK cells within the TME. Overall, this research sheds light on the functional heterogeneity of glioma and immune cells in the TME, providing potential targets for therapeutic intervention in this immunologically cold cancer.

cancer biology↗

bioRxiv2024

High Refractive Index Imaging Buffer for Dual Color 3D SMLM Imaging of Thick Samples

The current limitations of single-molecule localization microscopy (SMLM) in deep tissue imaging, primarily due to depth-dependent aberrations caused by refractive index (RI) mismatch, present a significant challenge in achieving high-resolution images at greater depths. To extend the imaging depth, we optimized the imaging buffer of SMLM with RI matched to the objective immersion medium, and systematically evaluated five different RI matched buffers, focusing on their impact on the blinking behavior of red-absorbing dyes and the quality of reconstructed super-resolution images. Particularly, we found clear unobstructed brain imaging cocktails (CUBIC) based imaging buffer could match the RI of oil and was able to clear the tissue samples. With the help of RI matched imaging buffer, we showed high quality dual color 3D SMLM images with imaging depth ranging from few microns to tens of microns in both cultured cells and sectioned tissue samples. This advancement offers a practical and accessible method for high-resolution imaging at greater depths without specialized optical equipment or expertise.

biophysics↗

bioRxiv2024

A PTER-dependent pathway of taurine metabolism linked to energy balance

Taurine is a conditionally essential micronutrient and one of the most abundant amino acids in humans1-3. In endogenous taurine metabolism, dedicated enzymes are involved in biosynthesis of taurine from cysteine as well as the downstream derivatization of taurine into secondary taurine metabolites4,5. One such taurine metabolite is N-acetyltaurine6. Levels of N-acetyltaurine are dynamically regulated by diverse physiologic perturbations that alter taurine and/or acetate flux, including endurance exercise7, nutritional taurine supplementation8, and alcohol consumption6,9. While taurine N-acetyltransferase activity has been previously detected in mammalian cells6,7, the molecular identity of this enzyme, and the physiologic relevance of N-acetyltaurine, have remained unknown. Here we show that the orphan body mass index-associated enzyme PTER (phosphotriesterase-related)10 is the principal mammalian taurine N-acetyltransferase/hydrolase. In vitro, recombinant PTER catalyzes bidirectional taurine N-acetylation with free acetate as well as the reverse N-acetyltaurine hydrolysis reaction. Genetic ablation of PTER in mice results in complete loss of tissue taurine N-acetyltransferase/hydrolysis activities and systemic elevation of N-acetyltaurine levels. Upon stimuli that increase taurine levels, PTER-KO mice exhibit lower body weight, reduced adiposity, and improved glucose homeostasis. These phenotypes are recapitulated by administration of N-acetyltaurine to wild-type mice. Lastly, the anorexigenic and anti-obesity effects of N-acetyltaurine require functional GFRAL receptors. Together, these data uncover enzymatic control of a previously enigmatic pathway of secondary taurine metabolism linked to energy balance.

biochemistry↗

bioRxiv2024

Spatial integration of sensory input and motor output in Pseudomonas aeruginosa chemotaxis through colocalized distribution

The opportunistic pathogen Pseudomonas aeruginosa serves as a model organism for studying multiple signal transduction pathways. The chemoreceptor cluster, a core component of the chemotaxis pathway, is assembled from hundreds of proteins. The unipolar distribution of receptor clusters has long been recognized, yet the precise mechanism governing their assembly remains elusive. Here, we directly observed the relative positions of the flagellar motor and chemoreceptor cluster using flagellar filament labeling and gene editing techniques. Surprisingly, we found that both are located at the same cell pole, with the distribution pattern controlled by the polar anchor protein FlhF. Additionally, the efficient assembly of the chemoreceptor cluster is partially dependent on the integrity of the motor structure. Furthermore, we discovered that overexpression of the chemotaxis regulatory protein CheY leads to high intracellular levels of the second messenger c-di-GMP, triggering cell aggregation. Therefore, the colocalization of the chemoreceptor cluster and flagellum in P. aeruginosa serves to avoid cross-pathway signaling interference, enabling cells to conduct various physiological activities in an orderly manner.

microbiology↗

bioRxiv2023

Fast and universal single molecule localization using multi-dimensional point spread functions

The recent development of single molecule imaging techniques has enabled not only high accuracy spatial resolution imaging but also information rich functional imaging. Abundant information of the single molecules can be encoded in its diffraction pattern and be extracted precisely (e.g. 3D position, wavelength, dipole orientation). However, sophisticated high dimensional point spread function (PSF) modeling and analyzing methods have greatly impeded the broad accessibility of these techniques. Here, we present a graphics processing unit (GPU)-based B-spline PSF modeling method which could flexibly model high dimensional PSFs with arbitrary shape without greatly increasing the model parameters. Our B-spline fitter achieves 100 times speed improvement and minimal uncertainty for each dimension, enabling efficient high dimensional single molecule analysis. We demonstrated, both in simulations and experiments, the universality and flexibility of our B-spline fitter to accurately extract the abundant information from different types of high dimensional single molecule data including multicolor PSF (3D + color), multi-channel four-dimensional 4Pi-PSF (3D + interference phase) and five-dimensional vortex PSF (3D + dipole orientation).

biophysics↗

bioRxiv2023

Optimal Sampling Rate for 3D Single Molecule Localization

Resolution of single molecule localization microscopy (SMLM) depends on the localization accuracy, which can be improved by utilizing engineered point spread functions (PSF) with delicate shapes. However, the intrinsic pixelation effect of the detector sensor will deteriorate PSFs under different sampling rates. The influence of the pixelation effect to the achieved 3D localization accuracy for different PSF shapes under different signal to background ratio (SBR) and pixel dependent readout noise has not been investigated in detail so far. In this work, we proposed a framework to characterize the 3D localization accuracy of pixelated PSF at different sampling rates. Four different PSFs (astigmatic PSF, double helix (DH) PSF, Tetrapod PSF and 4Pi PSF) were evaluated and the pixel size with optimal 3D localization performance were derived. This work provides a theoretical guide for the optimal design of sampling rate for 3D super resolution imaging.

bioengineering↗

bioRxiv2023

Neuronal lineage tracing from progenitors in human cortical organoids reveals novel mechanisms of human neuronal production, diversity, and disease

The contribution of progenitor subtypes to generate the billions of neurons during human cortical neurogenesis is not well understood. We developed the Cortical ORganoid Lineage Tracing (COR-LT) system for human cortical organoids. Differential fluorescent reporter activation in distinct progenitor cells leads to permanent reporter expression, enabling the progenitor cell lineage of neurons to be determined. Surprisingly, nearly all neurons produced in cortical organoids were generated indirectly from intermediate progenitor cells. Additionally, neurons of different progenitor lineages were transcriptionally distinct. Isogenic lines made from an autistic individual with and without a likely pathogenic variant in the CTNNB1 gene demonstrated that the variant substantially altered the proportion of neurons derived from specific progenitor cell lineages, as well as the lineage-specific transcriptional profiles of these neurons, suggesting a pathogenic mechanism for this mutation. These results suggest individual progenitor subtypes play unique roles in generating the diverse neurons of the human cerebral cortex. O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=194 SRC="FIGDIR/small/545314v1_ufig1.gif" ALT="Figure 1"> View larger version (26K): org.highwire.dtl.DTLVardef@da0038org.highwire.dtl.DTLVardef@44997dorg.highwire.dtl.DTLVardef@1b90ff2org.highwire.dtl.DTLVardef@c5dbcd_HPS_FORMAT_FIGEXP M_FIG O_FLOATNOGraphic AbstractC_FLOATNO C_FIG

neuroscience↗

bioRxiv2023

Traditionally fermented foods still a critical avenue impacting host gut antibiotic resistome

Disrupted gut microbiota as a critical risk factor for many noncommunicable diseases is largely driven by gut microbiota-impacting drugs, especially orally administrated as well as biliary excreted antibiotics. Fermented food consumption has been encouraged to replenish disrupted gut microbiota, but its overall impact on host gut health remains to be elucidated. This study examined retail traditionally fermented foods and gut microbiota of consumers of fermented foods for antibiotic resistome. Dietary intervention by fermented foods was found leading to a surge of the antibiotic resistome in gut microbiota of most human subjects. Antibiotic resistome was further illustrated in traditionally fermented food samples, and viable antibiotic resistant (AR) bacteria were recovered and highly prevalent in retail kimchi and artisan cheeses assessed in this pilot screening. Identified AR isolates included pathogens of importance in nosocomial infections such as Klebsiella pneumoniae, Enterococcus, etc., as well as commensals and lactic acid bacteria, some exhibited extremely high minimum inhibitory concentration (MIC) against antibiotics of clinical significance. Exposing fermented food microbiota to representative antibiotics further led to a boost of the corresponding antibiotic and multidrug-resistance gene pools and disturbed microbiota. These results revealed an underestimated public health risk associated with fermented foods intervention, particularly to susceptible population with gastrointestinal tract symptoms and compromised immune functions seeking gut microbiota rescue. The findings call for more comprehensive investigation and investment on the benefits and potential safety challenges associated with traditionally fermented foods, productive intervention of foodborne antibiotic resistance, and strategic movements to mitigate unnecessary damages to the host gut microbiota.

microbiology↗

bioRxiv2023

Human FAM111A inhibits vaccinia virus replication by degrading viral uncoating factor I3 and is antagonized by poxvirus host range factor SPI-1

Poxviruses are large double-stranded DNA viruses that infect a wide range of animals including humans. Since the eradication of smallpox, other members of the poxvirus family, such as monkeypox virus (MPXV) are still posing a great threat to public health. Vaccinia virus (VACV) is a prototypic poxvirus used as the vaccine strain for smallpox eradication. VACV encodes a serine protease inhibitor 1 (SPI-1) conserved in all orthopoxviruses, which has been recognized as a host range factor for modified vaccinia virus Ankara (MVA), an approved smallpox vaccine and a promising vaccine vector. FAM111A, a nuclear protein that regulates host DNA replication, was shown to restrict the replication of VACV-{Delta}SPI-1 in human cells. Nevertheless, the detailed antiviral mechanisms of FAM111A were unresolved. Here, we show that FAM111A is a potent restriction factor for VACV-{Delta}SPI-1 and MVA. Deletion of FAM111A rescued the replication of MVA and VACV-{Delta}SPI-1 and overexpression of FAM111A significantly reduced viral DNA replication and virus titers but did not affect viral early gene expression. The antiviral effect of FAM111A necessitated its trypsin-like protease domain and DNA binding domain but not the PCNA-interacting motif. We further discovered that FAM111A translocated into the cytoplasm upon VACV infection and this process was mediated by the cGAS-STING signaling pathway. Infection-triggered FAM111A degraded the nuclear pore complex via its protease activity, translocated to the cytoplasm, and interacted with and promoted the degradation of virus DNA binding protein I3 in a DNA-dependent manner. Interestingly, the protease activity of FAM111A was only needed for nuclear export but not I3 degradation as further analysis showed I3 was degraded through autophagy. Moreover, VACV SPI-1 was found primarily in the nucleus of infected cells and antagonized FAM111A by prohibiting its nuclear export. MPXV and lumpy skin disease virus SPI-1s also inhibited human FAM111A. Our findings reveal the detailed mechanism by which FAM111A functions to restrict a cytoplasmic DNA virus and provide explanations for the immune evasive function of VACV SPI-1.

microbiology↗

bioRxiv2022

A stable reference human transcriptome and proteome as a standard for reproducible omics experiments

In recent years, the development of high-throughput omics technology has greatly promoted the development of biomedicine. However, the poor reproducibility of omics techniques limits its application. It is necessary to use standard reference materials of complex RNAs or proteins to test and calibrate the accuracy and reproducibility of omics workflows. However, the transcriptome and proteome of most cell lines shift during culturing, which limits their applicability to serve as standard samples. In this study, we demonstrated that the human hepatocellular cell line MHCC97H has a very stable transcriptome (R2=0.966-0.995) and proteome (R2=0.934-0.976 for DDA, R2=0.942-0.986 for DIA) after 9 subculturing generations, which allows this stable standard sample to be stably produced on an industrial scale for several decades. Moreover, this stability was maintained across labs and platforms. In sum, our results justified a omics standard reference material and reference datasets for transcriptomic and proteomics research. This helps to further standardize the workflow and data quality of omics techniques and thus promotes the application of omics technology in precision medicine.

cell biology↗

bioRxiv2022

Autism-specific PTEN p.I135L mutation and an autism genetic background combine to dysregulate cortical neurogenesis

Alterations in cortical neurogenesis are implicated in neurodevelopmental disorders including autism spectrum disorders (ASDs). The contribution of genetic backgrounds, in additional to ASD risk genes, on cortical neurogenesis remain understudied. Here, using isogenic induced pluripotent stem cell (iPSC)-derived neural progenitor cells (NPCs) and cortical organoid models, we report that a heterozygous PTEN p.I135L mutation found in an ASD patient with macrocephaly activates PI3K/AKT and dysregulates cortical neurogenesis in an ASD genetic background-dependent fashion. Transcriptome analysis at both bulk and single cell level revealed PTEN p.I135L mutation and ASD genetic background affected genes involved in neurogenesis, neural development and synapse signaling. We also found that this PTEN p.I135L mutation led to overproduction of NPC subtypes as well as neuronal subtypes including both deep and upper layer neurons in its ASD background, but not when introduced into a control genetic background. These findings provide experimental evidence that both a PTEN p.I135L mutation and ASD genetic background contribute to cellular features consistent with ASD associated with macrocephaly.

genetics↗

bioRxiv2022

Highly Realistic Whole Transcriptome Synthesis through Generative Adversarial Networks

The transcriptome is the most extensive and standardized among all biological data, but its lack of inherent structure impedes the application of deep learning tools. This study resolves the neighborhood relationship of protein-coding genes through uniform manifold approximation and projection (UMAP) of high-quality gene expression data. The resultant transcriptome image is conducive to classification tasks and generative learning. Convolutional neural networks (CNNs) trained with full or partial transcriptome images differentiate normal versus lung squamous cell carcinoma (LUSC) and LUSC versus lung adenocarcinoma (LUAD) with over 96% accuracy, comparable to XGBoost. Meanwhile, the generative adversarial network (GAN) model trained with 93 TcgaTargetGtex transcriptome classes synthesizes highly realistic and diverse tissue/cancer-specific transcriptome images. Comparative analysis of GAN-synthesized LUSC and LUAD transcriptome images show selective retention and enhancement of epithelial identity gene expression in the LUSC transcriptome. Further analyses of synthetic LUSC transcriptomes identify a novel role for mitochondria electron transport complex I expression in LUSC stratification and prognosis. In summary, this study provides an intuitive transcriptome embedding compatible with generative deep learning and realistic transcriptome synthesis. Significance StatementDeep learning is most successful when the subject is structured. This study provides a novel way of converting unstructured gene expression lists to 2D-structured transcriptome portraits that are intuitive and compatible with a generative adversarial network (GAN)-based deep learning. The StyleGAN generator trained with transcriptome portrait libraries synthesizes tissue- and disease-specific transcriptomes with significant diversity. Detailed analyses of the synthetic transcriptomes reveal selective enhancement of clinically significant features not apparent in the original transcriptome. Therefore, transcriptome-image-based generative learning may become a significant source of de novo insight generation.

bioinformatics↗

bioRxiv2022

Field dependent deep learning enables high-throughput whole-cell 3D super-resolution imaging

Single-molecule localization microscopy (SMLM) in a typical wide-field setup has been widely used for investigating sub-cellular structures with super resolution. However, field-dependent aberrations restrict the field of view (FOV) to only few tens of micrometers. Here, we present a deep learning method for precise localization of spatially variant point emitters (FD-DeepLoc) over a large FOV covering the full chip of a modern sCMOS camera. Using a graphic processing unit (GPU) based vectorial PSF fitter, we can fast and accurately model the spatially variant point spread function (PSF) of a high numerical aperture (NA) objective in the entire FOV. Combined with deformable mirror based optimal PSF engineering, we demonstrate high-accuracy 3D SMLM over a volume of ~180 x 180 x 5 m3, allowing us to image mitochondria and nuclear pore complex in the entire cells in a single imaging cycle without hardware scanning - a 100-fold increase in throughput compared to the state-of-the-art.

biophysics↗

bioRxiv2022

Hybrid Synthesis of bioplastics polyhydroxybutyrate from carbon dioxide

The accelerating environmental crisis has intensified the demand for switching from traditional economy to a renewable one with a reduced carbon footprint. Here we reported a hybrid system, coupling chemical process of CO2 hydrogen reduction and biological process for polyhydroxybutyrate (PHB) synthesis, that utilized CO2 as a raw material to produce PHB in vitro. The synthetic pathway of PHB was optimized by screening more efficient methanol oxidases, high activity mutants of glycolaldehyde synthase and coordinating enzyme dosages in the pathway, which achieved the carbon yield of 93.6% for producing PHB from methanol. Finally, by combining with the chemical process from CO2 to methanol, a scaling-up bio-system was performed to convert CO2 into PHB, yielding 5.8 g/L with the productivity of 1.06 g-1L-1h-1. This approach represents a promising carbon-neutral way to produce biodegradable plastics.

synthetic biology↗

bioRxiv2022

Programming the lifestyles of engineered bacteria for cancer therapy

Bacteria can be genetically engineered to act as therapeutic delivery vehicles in the treatment of tumors, killing cancer cells or activating the immune system. This is known as Bacteria-Mediated Cancer Therapy (BMCT). Tumor invasion, colonization and tumor regression are major biological events, which are directly associated with antitumor effects and are uncontrollable due to the influence of tumor microenvironments during the BMCT process. Here, we developed a genetic circuit for dynamically programming bacterial lifestyles (planktonic, biofilm or lysis), to precisely manipulate the process of bacterial adhesion, colonization and drug release in BMCT process, via hierarchical modulation of the lighting power density (LPD) of near-infrared (NIR) light. The deep tissue penetration of NIR offers us a modality for spatiotemporal and noninvasive control of bacterial genetic circuits in vivo. By combining computational modeling with high throughput characterization device, we optimized the genetic circuits in engineered bacteria to program the process of bacterial lifestyle transitions by altering the illumination scheme of NIR. Our results showed that programming intratumoral bacterial lifestyle transitions allows precise control of multiple key steps throughout the BMCT process, and therapeutic efficacy can be greatly improved by controlling the localization and dosage of therapeutic agents via optimizing the illumination scheme.

synthetic biology↗

bioRxiv2022

Transcriptomic analysis reveals hub genes and pathways in response to acetic acid stress in Kluyveromyces marxianus during high-temperature ethanol fermentation

The thermotolerant yeast Kluyveromyces marxianus has great potential for high-temperature ethanol fermentation, but it produces excess acetic acid during high-temperature fermentation, which inhibits ethanol production. The mechanisms of K. marxianuss responses to acetic acid have not been fully understood. In this study, the transcriptomic changes of K. marxianus DMKU3-1042 resulted from acetic acid stress during high-temperature ethanol fermentation were investigated based on high-throughput RNA sequencing. We identified 611 differentially expressed genes (DEGs) under acetic acid stress (fold change > 2 or < 0.5, P-adjust <0.05), with 166 up-regulated and 445 down-regulated. GO terms and pathways enriched in these DEGs were identified. Protein-protein interaction (PPI) networks were constructed based on the interactions between proteins coded by the DEGs, and hub genes and key modules in the PPI networks were identified. The results in this study indicated that during high-temperature fermentation, acetic acid stress promoted protein catabolism but repressed protein synthesis, which affected the growth and metabolism of K. marxianus and led to the decrease of ethanol production. The findings in this study provide a better understanding of the response mechanism of K. marxianus to acetic acid stress, and provide a basis for subsequent increase of ethanol production by K. marxianus.

microbiology↗

bioRxiv2022

Privacy-preserving integration of multiple institutional data for single-cell type identification with scPrivacy

The rapid accumulation of large-scale single-cell RNA-seq datasets from multiple institutions presents remarkable opportunities for automatically cell annotations through integrative analyses. However, the privacy issue has existed but being ignored, since we are limited to access and utilize all the reference datasets distributed in different institutions globally due to the prohibited data transmission across institutions by data regulation laws. To this end, we present scPrivacy, which is the first and generalized automatically single-cell type identification prototype to facilitate single cell annotations in a data privacy-preserving collaboration manner. We evaluated scPrivacy on a comprehensive set of publicly available benchmark datasets for single-cell type identification to stimulate the scenario that the reference datasets are rapidly generated and distributed in multiple institutions, while they are prohibited to be integrated directly or exposed to each other due to the data privacy regulations, demonstrating its effectiveness, time efficiency and robustness for privacy-preserving integration of multiple institutional datasets in single cell annotations.

bioinformatics↗

bioRxiv2022

Deformable Mirror based Optimal PSF Engineering for 3D Super-resolution Imaging

Point spread function (PSF) engineering is an important technique to encode the properties (e.g., 3D positions, color, and orientation) of single molecule in the shape of the PSF, often with the help of a programmable phase modulator. Deformable mirror (DM) is currently the most widely used phase modulator for fluorescence detection as it shows negligible photon loss. However, it relies on careful calibration for precise wavefront control. Therefore, design of an optimal PSF not only relies on the theoretical calculation of maximum information content, but also the physical behavior of the phase modulator, which is often ignored during the optimization process. Here, we developed a framework of PSF engineering which could generate a device specific optimal PSF for 3D super-resolution imaging using DM. We used our method to generate two types of PSFs with depths of field comparable to the widely used astigmatism and Tetrapod PSFs, respectively. We demonstrated the superior performance of the DM specific optimal PSF over the conventional astigmatism and Tetrapod PSF both theoretically and experimentally.

biophysics↗