Biology subjects

Li, S.

Publications and source records attributed to Li, S..

At least 541 records · Page 30Linked to original sources

bioRxiv2024

The Identification Markers of activated myofibroblast subsets in the Human Lung Fibrosis Ecosystem via integrated omics Analysis

BackgroundThe aberrant remodeling of the extracellular matrix (ECM) is closely associated with lung fibrosis. However, the mechanisms underlying ECM remodeling in pulmonary fibrosis (PF) remain unclear. The advent of single-cell RNA sequencing (scRNA-seq) has provided valuable insights into the diverse phenotypic and functional characteristics of human PF. Nevertheless, the dynamic of ECM remodeling in terms of ECM synthesizing and the potential activating markers of myofibroblasts in the human PF microenvironment still needs to be investigated. MethodsWe performed integrative scRNA-seq analyses on high-fidelity PF data from a public platform by filtering out the low-quality counts and doublets using two doublet prediction methods. Next, we investigated the dynamic of the ECM signature in diverse cells in PF and screened the potential markers of myofibroblasts via fitting a successful polynomial regression model. Finally, the markers of activated myofibroblasts were identified using bulk RNA-seq of pulmonary tissue. ResultsFirst, we depicted the pathogenic landscape and demonstrated the heterogeneity of ECM in PF by integratively analyzing single-cell RNA-seq data, and we hypothesized that myofibroblasts played a significant role in ECM formation. Second, our results successfully displayed the biological dynamic changes of ECM and investigated the 73 positive correlated genes of myofibroblasts in PF via a polynomial regression model. Then, the bulk RNA-seq results further identified eight new activating markers of myofibroblasts, such as MFAP2, MXRA5, and LRRC17 via transcriptomic signature, correlation and ROC scores. Finally, the results of cell-cell interaction indicated that myeloid cells may be involved in regulating ECM remodeling through proliferation mediated by myofibroblasts that secrete POSTN, suggesting that ECM remodeling in PF is a complex and multi-participated process. ConclusionsIn summary, we provided insights into the contributions of ECM in human PF by integrative analysis and highlighted potential clinical utilities of myofibroblast subsets as therapeutic targets.

bioinformatics↗

bioRxiv2024

Aerobic methane production by methylotrophic Methylotenera in groundwater

Methylotenera are signature denitrifiers and methylotrophs commonly found together with methanotrophic bacteria in lakes and freshwater sediments. Here we show that three distinct Methylotenera ecotypes were abundant in methane-rich, Pleistocene-aged groundwaters. Just like in surface water biomes, groundwater Methylotenera often co-occurred with methane-oxidizing bacteria, even though they were generally unable to denitrify. One abundant Methylotenera ecotype expressed a pathway for aerobic methane production from methylphosphonate. This phosphate-acquisition strategy was recently found to contribute to methane production in the oligotrophic, oxic upper ocean. Gene organization, phylogeny and 3D protein structure of the key enzyme, C-P lyase subunit PhnJ were consistent with a role in phosphate uptake. We conclude that phosphate may be a limiting nutrient in productive, methane rich aquifers and that methylphosphonate degradation can contribute to groundwater methane production.

microbiology↗

bioRxiv2024

Reward history guides attentional selection in whisker somatosensory (S1) cortex

Prior reward is a potent cue for attentional capture, but the underlying neurobiology is largely unknown. In a novel whisker touch detection task, we show that mice flexibly shift attention between specific whiskers on a trial-by-trial timescale, guided by the recent history of stimulus-reward association. Two-photon calcium imaging and spike recordings revealed a robust neurobiological correlate of attention in the somatosensory cortex (S1), boosting sensory responses to the attended whisker in L2/3 and L5, but not L4. Attentional boosting in L2/3 pyramidal cells was topographically precise and whisker-specific, and shifted receptive fields toward the attended whisker. L2/3 VIP interneurons were broadly activated by whisker stimuli, motion, and arousal but did not carry a whisker-specific attentional signal, and thus did not mediate spatially focused tactile attention. Together, these findings establish a new model of focal attention in the mouse whisker tactile system, showing that the history of stimuli and rewards in the recent past can dynamically engage local modulation in cortical sensory maps to guide flexible shifts in ongoing behavior.

neuroscience↗

bioRxiv2024

The evolutionary cost of homophily: social stratification facilitates stable variant coexistence and increased rates of evolution in host-associated pathogens

Coexistence of multiple strains of a pathogen in a host population can present significant challenges to vaccine development or treatment efficacy. Here we discuss a novel mechanism that can increase rates of long-lived strain polymorphism, rooted in the presence of social structure in a host population. We show that social preference of interaction, in conjunction with differences in immunity between host subgroups, can exert varying selection pressure on pathogen strains, creating a balancing mechanism that supports stable viral coexistence, independent of other known mechanisms. We use population genetic models to study rates of pathogen heterozygosity as a function of population size, host population composition, mutant strain fitness differences and host social preferences of interaction. We also show that even small periodic epochs of host population stratification can lead to elevated strain coexistence. These results are robust to varying social preferences of interaction, overall differences in strain fitnesses, and spatial heterogeneity in host population composition. Our results highlight the role of host population social stratification in increasing rates of pathogen strain diversity, with effects that should be considered when designing policies or treatments with a long-term view of curbing pathogen evolution.

evolutionary biology↗

bioRxiv2024

Biophysical Modeling and Experimental Analysis of the Dynamics of C. elegans Body-Wall Muscle Cells

This study combines experimental techniques and mathematical modeling to investigate the dynamics of C. elegans body-wall muscle cells. Specifically, by conducting voltage clamp and mutant experiments, we identify key ion channels, particularly the L-type voltage-gated calcium channel (EGL-19) and potassium channels (SHK-1, SLO-2), which are crucial for generating action potentials. We develop Hodgkin-Huxley-based models for these channels and integrate them to capture the cells electrical activity. To ensure the model accurately reflects cellular responses under depolarizing currents, we develop a parallel simulation-based inference method for determining the models free parameters. This method performs rapid parallel sampling across high-dimensional parameter spaces, fitting the model to the responses of muscle cells to specific stimuli and yielding accurate parameter estimates. We validate our model by comparing its predictions against cellular responses to various current stimuli in experiments and show that our approach effectively determines suitable parameters for accurately modeling the dynamics in mutant cases. Additionally, we discover an optimal response frequency in body-wall muscle cells, which corresponds to a burst firing mode rather than regular firing mode. Our work provides the first experimentally constrained and biophysically detailed muscle cell model of C. elegans, and our analytical framework combined with robust and efficient parametric estimation method can be extended to model construction in other species. Author summaryDespite the availability of many biophysical neuron models of C. elegans, a biologically detailed model of its muscle cell remains lacking, which hampers an integrated understanding of the motion control process. We conduct voltage clamp and mutant experiments to identify ion channels that influence the dynamics of body-wall muscle cells. Using these data, we establish Hodgkin-Huxley-based models for these ion channels and integrate them to simulate the electrical activity of the muscle cells. To determine the free parameters of the model, we develop a simulation-based inference method with parallel sampling that aligns the model with the muscle cells responses to specific stimuli. Our method allows for swift parallel sampling of parameters in high dimensions, facilitating efficient and accurate parameter estimation. To validate the effectiveness of the determined parameters, we verify the cells responses under different current stimuli in wild type and mutant cases. Furthermore, we investigate the optimal response frequency of body-wall muscle cells and find that it exhibits a frequency consistent with burst firing mode rather than regular firing mode. Our research introduces the first experimentally validated and biophysically detailed model of muscle cells in C. elegans. Additionally, our modeling and simulation framework for efficient parametric estimation in high-dimensional dynamical systems can be extended to model constructions in other scenarios.

neuroscience↗

bioRxiv2024

Metabolic conservation by protein quality control in Campylobacter jejuni underlies the antibiotic tolerance

Bacterial persistence enables survival during lethal antibiotic exposure and is implicated in recurrent infections, yet the physiology underlying bacterial persistence in many pathogens remains poorly defined. Here we show that exposure of Campylobacter jejuni to ampicillin or ciprofloxacin generates an antibiotic-persistent subpopulation. Rather than undergoing global metabolic shutdown, persister cells adopted a metabolically constrained state characterized by selective maintenance of oxidative phosphorylation and bioenergetic metabolism through coordinated proteostasis control. The ATP-dependent protease ClpP was essential for entry into this persistent state. Loss of ClpP disrupted proteostasis of the electron transport chain, specifically impaired bd-like terminal oxidase integrity, and reduced survival in vivo and in macrophages. These findings identify ClpP-dependent maintenance of redox and bioenergetic homeostasis as critical determinants of C. jejuni persistence and highlight metabolic remodeling as a defining feature of antibiotic tolerance. These insights may inform future therapeutic strategies aimed at disrupting persistence and improving antibiotic efficacy.

microbiology↗

bioRxiv2024

Apoptotic caspases cleave DRP1 to promote mitochondrial fusion and anti-viral immune responses

Apoptosis has been recognized as a suicidal host-defense programmed cell death pathway against invading pathogens. However, recent evidences showed that viruses can employ caspases to cleave and inactivate immune signaling molecules to facilitate infection. Whether caspases can instead promote anti-viral immune responses is currently unknown. Here, we demonstrated that the NSs protein of RVFV triggers activation of apoptotic caspases, which cleave the mitochondrial fission factor DRP1 resulting in mitochondrial elongation. Elongated mitochondria promote MAVS aggregation leading to enhanced anti-viral immunity. Apoptotic caspases, including caspase-3, -6, -7 and -8, cleave DRP1 at the motifs of D500FAD503 and/or AEAD556, suggesting that this cleavage event may occur during infection of different viruses. Indeed, infection of H1N1, SeV and HSV-1 all triggered apoptotic caspases activation to cleave DRP1 promoting anti-viral immune responses. Compared with wild-type DRP1, introduction of caspase-resistant DRP1 strongly attenuated immune responses triggered by virus infection. These results revealed a mechanism through which apoptotic caspases promote anti-viral immunity by regulating mitochondrial morphodynamics.

microbiology↗

bioRxiv2024

Tumor Subtype Classification Tool for HPV-associated Head and Neck Cancers

ImportanceMolecular subtypes of HPV-associated Head and Neck Squamous Cell Carcinoma (HNSCC), named IMU (immune strong) and KRT (highly keratinized), are well-recognized and have been shown to have distinct mechanisms of carcinogenesis, clinical outcomes, and potentially differing optimal treatment strategies. Currently, no standardized method exists to subtype a new HPV+ HNSCC tumor. Our paper introduces a machine learning-based classifier and webtool to reliably subtype HPV+ HNSCC tumors using the IMU/KRT paradigm and highlights the importance of subtype in HPV+ HNSCC. ObjectiveTo develop a robust, accurate machine learning-based classification tool that standardizes the process of subtyping HPV+ HNSCC, and to investigate the clinical, demographic, and molecular features associated with subtype in a meta-analysis of four patient cohorts. Data SourcesWe conducted RNA-seq on 67 HNSCC FFPE blocks from University of Michigan hospital. Combining this with three publicly available datasets, we utilized a total of 229 HPV+ HNSCC RNA-seq samples. All participants were HPV+ according to RNA expression. An ensemble machine learning approach with five algorithms and three different input training gene sets were developed, with final subtype determined by majority vote. Several additional steps were taken to ensure rigor and reproducibility throughout. Study SelectionThe classifier was trained and tested using 84 subtype-labeled HPV+ RNA-seq samples from two cohorts: University of Michigan (UM; n=18) and TCGA-HNC (n=66). The classifier robustness was validated with two independent cohorts: 83 samples from the HPV Virome Consortium and 62 additional samples from UM. We revealed 24 of 39 tested clinicodemographic and molecular variables significantly associated with subtype. ResultsThe classifier achieved 100% accuracy in the test set. Validation on two additional cohorts demonstrated successful separation by known features of the subtypes. Investigating the relationship between subtype and 39 molecular and clinicodemographic variables revealed IMU is associated with epithelial-mesenchymal transition (p=2.25x10-04), various immune cell types, and lower radiation resistance (p=0.0050), while KRT is more highly keratinized (p=2.53x10-08), and more likely female than IMU (p=0.0082). Conclusions and RelevanceThis study provides a reliable classifier for subtyping HPV+ HNSCC tumors as either IMU or KRT based on bulk RNA-seq data, and additionally, improves our understanding of the HPV+ HNSCC subtypes.

bioinformatics↗

bioRxiv2024

Temporal-spatially metabolic reprogramming rewires the H3K27ac landscape to enable the initiation of liver regeneration

The liver possesses extensive regenerative capacity. Nevertheless, the most proximal events driving the transition from quiescent to proliferative hepatocytes remain largely elusive. Using the combination of spatiotemporal metabolomics and transcriptomics, our study mapped out the temporal-spatial landscape of metabolic reprogramming, epigenetic remodeling, and transcriptomic rewiring from 3 to 12 hours post-partial hepatectomy. Specifically, we identified a profound metabolic shift towards hyperactive fatty acid oxidation (FAO) and suppressed phospholipid biosynthesis during the preparation phase of liver regeneration, which were surprisingly reversed afterwards. FAO-dependent accumulation of Acetyl-CoA particularly remodeled H3K27ac landscape. These metabolic reprograming and epigenetic regulation were spatially specific, aligning with the zonation of hepatocyte proliferation. Blocking FAO in etomoxir-treated or hepatocyte-specific Cpt1a knockout mice, suppressing Acetyl-CoA biosynthesis, and inhibiting histone acetyltransferase all resulted in lethal liver regeneration deficiency. CUT&Tag analysis further revealed that the reshaping of H3K27ac profiles favored the transcription of genes associated with cell cycle transition and mitosis, and rewired the metabolic gene network. Collectively, we highlight a previously underappreciated role of FAO in epigenetic remodeling that is essential for the initiation of liver regeneration, offering exciting opportunity for the rescue of regeneration-deficient livers. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=181 HEIGHT=200 SRC="FIGDIR/small/602368v1_ufig1.gif" ALT="Figure 1"> View larger version (61K): org.highwire.dtl.DTLVardef@8dd836org.highwire.dtl.DTLVardef@6ddb27org.highwire.dtl.DTLVardef@4f1e49org.highwire.dtl.DTLVardef@4d7afe_HPS_FORMAT_FIGEXP M_FIG C_FIG

cell biology↗

bioRxiv2024

VirID: Beyond Virus Discovery - An Integrated Platform for Comprehensive RNA Virus Characterization

RNA viruses exhibit vast phylogenetic diversity and can significantly impact public health and agriculture. However, current bioinformatics tools for viral discovery from metagenomic data frequently generate false positive virus results, overestimate viral diversity, and misclassify virus sequences. Additionally, current tools often fail to determine virus-host associations, which hampers investigation of the potential threat posed by a newly detected virus. To address these issues we developed VirID, a software tool specifically designed for the discovery and characterization of RNA viruses from metagenomic data. The basis of VirID is a comprehensive RNA-dependent RNA polymerase (RdRP) database to enhance a workflow that includes RNA virus discovery, phylogenetic analysis, and phylogeny-based virus characterization. Benchmark tests on a simulated data set demonstrated that VirID had high accuracy in profiling viruses and estimating viral richness. In evaluations with real-world samples, VirID was able to identity RNA viruses of all type, but also provided accurate estimations of viral genetic diversity and virus classification, as well as comprehensive insights into virus associations with humans, animals, and plants. VirID therefore offers a robust tool for virus discovery and serves as a valuable resource in basic virological studies, pathogen surveillance, and early warning systems for infectious disease outbreaks.

bioinformatics↗

bioRxiv2024

Insights into non-crossover recombination from long-read sperm sequencing

Meiotic recombination is a fundamental process that generates genetic diversity by creating new combinations of existing alleles. Although human crossovers have been studied at the pedigree, population and single-cell level, the more frequent non-crossover events that lead to gene conversion are harder to study, particularly at the individual level. Here we show that single high-fidelity long sequencing reads from sperm can capture both crossovers and non-crossovers, allowing effectively arbitrary sample sizes for analysis from one male. Using fifteen sperm samples from thirteen donors we demonstrate variation between and within donors for the rates of different types of recombination. Intriguingly, we observe a tendency for non-crossover gene conversions to occur upstream of nearby PRDM9 binding sites, whereas crossover locations have a slight downstream bias. We further provide evidence for two distinct non-crossover processes. One gives rise to the vast majority of non-crossovers with mean conversion tract length under 50bp, which we suggest is an outcome of standard PRDM9-induced meiotic recombination. In contrast [~]2% of non-crossovers have much longer mean tract length, and potentially originate from the same process as complex events with more than two haplotype switches, which is not associated with PRDM9 binding sites and is also seen in somatic cells.

genetics↗

bioRxiv2024

A chromosome-level genome assembly of Dracaena cambodiana and comparative genomics analysis highlights the distinct biological features of two resource species of dragon's blood

This study reports a chromosome-level genome for Dracaena cambodiana, one of two typical dracaena species in China. This work will help to deepen the understanding of the dracaena species and the conservation and development of plant resources. The final assembly consisted of 54 scaffolds, spanning 1.08 Gb, with a scaffold N50 size of 52.29 Mb, encoded 36860 predicted protein-coding genes. A total of 1,064,810,157 bp of genome sequences were located on 20 chromosomes (2n = 40), accounting for 98.46%. We investigate the possible mechanisms of the longevity of dracaena, the longest-lived plant in the world, which involve DNA repair and post-translational modification. We also performed comparative genomic analysis of the previously assembled genome of Dracaena cochinchinesis with this genome, and found that the two involved interaction of plant-pathogen interaction and ubiquitin mediated proteolysis, which may reveal why Dracaena has environmental adaptability and longevity characteristics.

genomics↗

bioRxiv2024

A new yeast-based bioreporter for simple, sensitive, and cost-effective detection of dioxin-like compounds

Dioxin-like compounds (DLCs) are environmental xenobiotics that can activate the aryl hydrocarbon receptors (AhR), thereby imposing a significant threat to human health through biomagnifications processes. In this study, a dioxin-activated nano-luminescent Saccharomyces cerevisiae bioreporter, called DnaSc, was developed for simple and rapid detection of DLCs and AhR agonists. The bioreporter used nano-luciferase NLuc as a signal generator to emit bioluminescent signals in response to DLCs without cell lysis. Through optimizing ARNT expression and engineering the aryl hydrocarbon receptor (AhR), the yeast-based bioassay exhibited a detection limit of 10 fM for 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) within 6 h, making it the most sensitive whole-cell biosensor reported to date. Furthermore, the detection capacity of the DnaSc bioassay for DLCs and AhR agonists was characterized. In summary, the yeast-based bioreporter developed in this study provided a simple, sensitive, and cost-effective method for DLCs detection.

bioengineering↗

bioRxiv2024

Identification of mCMQ069, a novel antimalarial with potential for a single-dose cure and/or 28-day chemoprevention

In efforts towards eliminating malaria, a discovery program was initiated to identify a novel antimalarial using KAF156 as a starting point. Following the most recent TCP/TPP guidelines, we have identified mCMQ069 with a predicted single oral dose for treatment ([~]40-106 mg) and one-month chemoprevention ([~]96-216 mg). We have improved unbound MPC and predicted human clearance by 18-fold and 10-fold respectively when compared to KAF156.

microbiology↗

bioRxiv2024

Rbm24 maintains survival of cochlear outer hair cells by repressing Insm1

The inactivation of Rbm24, an RNA-binding protein, results in the degeneration of cochlear outer hair cells (OHCs) during the postnatal period. However, the specific molecular mechanisms underlying this OHC death remain elusive. To address this, we conducted a comprehensive analysis comparing the gene profiles of wild-type OHCs to those lacking Rbm24 (Rbm24-/-) at postnatal day 7 (P7). Our results revealed that the overall differentiation program of OHCs is delayed in the absence of Rbm24. Furthermore, the expression of Insm1, a crucial factor for OHC development that is normally switched off by P2, remains prolonged in Rbm24-/- OHCs. Interestingly, when Insm1 is overexpressed, it also leads to OHC death. Significantly, the OHC degeneration is much less severe when both Rbm24 and Insm1 are simultaneously inactivated. These findings shed light on the important role of Rbm24 in repressing Insm1 and its impact on OHC differentiation and survival. Our study provides valuable insights into the complex genetic signaling pathways involved in OHC development.

neuroscience↗

bioRxiv2024

Single-cell RNA Sequencing Reveals Methamphetamine Inhibits the Liver Immune Response with Involvement of the Dopamine D1 Receptor

Methamphetamine (METH) is a highly addictive psychostimulant that causes physical and psychological damage and immune system disorder, especially in the liver, which contains a significant number of immune cells. Dopamine, which is a key neurotransmitter in METH addiction and immune regulation, plays a crucial role in this process. In this study, we developed a chronic METH administration model and conducted single-cell RNA sequencing to investigate the effect of METH on liver immune cells and the involvement of the dopamine receptor D1 (DRD1) in this process. Our findings revealed that chronic exposure to METH induced an immune cell shift from Ifitm3+Mac and Ccl5+Mac to Cd14+Mac, and from Fyn+CD4+Teff, CD8+T, and NKT to Fos+CD4+T and Rora+ILC2, along with suppression of multiple immune functional pathways. DRD1 was implicated in the regulation of some of these pathways and the shifts of hepatic immune cells. This research provides valuable insights into the development of therapies aimed at mitigating METH-induced immune impairment.

immunology↗

bioRxiv2024

Synergistic amplifier reprograms biosensor behavior to facilitate detection of dioxin-like compounds

Biosensors are prominent detection tools for evaluating various analytical markers. However, these devices that meet practical application scenarios are still limited, and their potential remains to be developed. In these aspects, we attempted to design and construct a synergistic amplifier consisting of two components, namely, a transcriptional activation component mediated by the Gal3C regulator and a transcription recruitment component exploiting the function of dCas9-(SpyC)n, which work together to enhance yeast biosensor performance. This synergistic amplifier increased the signal output by 5.1-folds and the detection limit by 4.4-folds, respectively, while maintaining adjustable sensitivity and avoiding noise introduction during signal amplification. We demonstrated the use of synergistic amplifier in detecting dioxin analogues, aiming to unlock the potential of predictive modulation, and found that it achieved progress in dynamic output and detection limit. This work show that synergistic amplifier is a new paradigm for expanding signal processing pathways within synthetic genetic networks, enabling cell-based biosensors for environmental monitoring.

molecular biology↗

bioRxiv2024

Molecular Architecture of Monkeypox Mature Virus

Since the 2022 mpox outbreak, MPXV has caused [~]100,000 infected cases with [~]200 deaths across 117 countries. and was declared a public health emergency of international concern by the WHO. The causative pathogen, monkeypox virus (MPXV), is a zoonotic double-stranded DNA orthopoxvirus. To investigate the structures and replication mechanism of MPXV, the MPXV recombinant proteins and vaccinia virus (VACV) particles have been studied by cryo-EM, however, in situ structural insights into major structural proteins and assembly of the authentic MPXV particles are missing. In this work, we isolated two MPXV strains from the first imported mpox case and the first local mpox case in mainland China. From the two strains, we propagated and purified mature viruses, and applied cryo-electron tomography (cryo-ET) and sub-tomogram averaging (STA) to unveil the architecture of intact MPXV virus. Interestingly, we also discovered irregularly-shaped mature virions with distorted core walls. To our knowledge, these in situ structural insights in MPXV have not been reported before.

biophysics↗