Biology subjects

Sun, J.

Publications and source records attributed to Sun, J..

At least 199 records · Page 11Linked to original sources

bioRxiv2024

Long term rescue of Alzheimer deficits in vivo by one-time gene-editing of App C-terminus.

Gene-editing technologies promise to create a new class of therapeutics that can achieve permanent correction with a single intervention. Besides eliminating mutant alleles in familial disease, gene-editing can manipulate upstream pathophysiologic events and alter disease-course in wider patient populations. Here we use CRISPR-Cas9 to edit the last exon of amyloid precursor protein (App), relevant for Alzheimers disease (AD). Our strategy effectively eliminates an endocytic (YENPTY) motif at APP C-terminus in mouse and human neurons, while preserving N-terminus and compensatory APP-homologues. This manipulation favorably alters events along the amyloid-pathway; inhibiting toxic APP-beta-cleavage fragments (including Abeta) and upregulating neuroprotective APP-alpha-cleavage. AAV-editing ameliorates neuropathologic, electrophysiologic, and behavioral deficits in an AD knockin mouse model. Effects persist for many months with no detectable abnormalities in germline-edited WT mice, and pathologic alterations in glial-transcriptomes are also normalized. Our strategy takes advantage of innate transcriptional rules that render terminal exons insensitive to nonsense-decay, and this upstream manipulation is expected to be effective for all forms of AD.

neuroscience↗

bioRxiv2024

Adaptive loss of shortwave cone opsins during genomic evolution in cartilaginous fish

There is ample evidence of the loss of the shortwave visual protein gene in cartilaginous fish. However, the underlying logic and mechanisms by which organisms need to adapt to the environment behind the opsin loss are still unclear. Here, we report the assembly structure of the whole genome of Okamejei kenojei and Prionace glauca, identify TcMar difference between skates/rays and sharks/chimaeras, and analyze the distribution characteristics and intra group differentiation of opsin-related genes in cartilaginous fish. By establishing a zebrafish model with short wave opsin gene deletion, we find blue or violet light via short-wave sensitive opsins SWS1 or SWS2 can cause the photoreceptor layer thinning (the biomarker for age-related macular degeneration in human eye) through enactive the cell aging. The loss of sws is helpful for alleviating the short-wave light damage on the eye. Since the tapetum lucidum in the eye is found broad existence in various cartilaginous fish, a logical hypothesis was creatively proposed that the existence of tapetum lucidum on the retina of cartilaginous fish is interdependent with the loss of shortwave visual protein gene, providing a new perspective and explanatory path for further understanding of the evolution of visual genes in cartilaginous fish.

bioinformatics↗

bioRxiv2024

Imaging of porphyrin-specific fluorescence in pathogenic bacteria in vitro using a wearable, hands-free system

HighlightsO_LIFluorescence imaging detects porphyrins in bacteria via natural fluorescence. C_LIO_LIA lightweight, hands-free device enables rapid, non-invasive clinical assessments. C_LIO_LIThe study tested 15 bacterial and 2 fungal strains for porphyrin-based autofluorescence. C_LIO_LI14 bacteria fluoresced on Porphyrin Test Agar, 9 on blood agar plates. C_LIO_LIThe REVEAL system aids in diagnosing infections and guiding real-time treatments. C_LI Fluorescence imaging is an effective method for detecting porphyrin production in bacteria, leveraging the natural fluorescence properties of porphyrins. Here we use a simple, lightweight, hands-free device for rapid, non-invasive assessments in clinical settings, microbial research, and diagnostic applications. Specifically in this study, we examined 15 bacterial and 2 fungal strains commonly associated with skin, oral, and/or multi-site infections at wound sites for their ability to autofluoresce based on their porphyrin production. We utilized Remel Porphyrin Test Agar and blood agar plates to monitor red fluorescence over several days of growth under aerobic or anaerobic conditions using the wearable REVEAL FC imaging system with a 405 nm violet excitation headlight paired with eyewear carrying 430 nm emission lenses. Fourteen of the fifteen bacteria produced red fluorescence when grown on Porphyrin Test Agar and nine of the fifteen bacteria also displayed red fluorescence on blood agar plates, consistent with their ability to synthesize porphyrins. Taken together, our results elucidate the sensitivity, effectiveness, and convenience of using wearable technology to detect pathogens that produce porphyrin-specific fluorescence. Consequently, the REVEAL system has immense potential to help diagnose wound infections, direct clinical procedures, and guide treatment options in real-time using fluorescence imaging all while minimizing the risk of contamination.

microbiology↗

bioRxiv2024

SLAMseq reveals transfer of RNA from liver to kidney in the mouse

Extracellular RNA (exRNA) mediates intercellular communication in plants and lower animals; whether it serves a signalling function in mammals is controversial. Reductionist experiments, in which a single RNA is over-expressed or tagged, have shown RNA transfer between tissues but these may not be relevant to normal physiology. For example, the microRNA miR-122 is released from injured hepatocytes and is taken up by kidney cells. We sought to determine the scale of RNA transfer between liver and kidney through the metabolic labelling of RNA in mice. We used 4-thiouracil to specifically label RNA in hepatocytes then detected labelled (thiolated) RNA in the kidney using SLAMseq: SH-Linked Alkylation for the Metabolic sequencing of RNA. In the kidney, mRNA labelling was detected in 5% of all kidney transcripts under healthy conditions and was increased to 34% of kidney transcripts after acute hepatocellular injury. Labelling was evident in kidney transcripts mapping to known hepatocyte marker genes, to a greater extent than those mapping to markers of other cell types. Labelled small RNA was not detected in kidney tissue. Our results are consistent with the transfer of RNA from liver to kidney; this transfer is augmented in liver injury.

molecular biology↗

bioRxiv2024

The complete genome of lettuce reveals centromere landscape and empowers breeding

Lettuce (Lactuca sativa L.) is a globally grown vegetable crop as the most popular salad ingredient. Lettuce breeding is crucial to enhancing yield, nutrition and disease resistance, but impeded by lacking a high-quality genome resource. In addition, the released genomes remain fragmented (with hundreds of gaps) and incomplete with omitting pivotal centromeres and telomeres. Here, we report a 2.59 Gb complete telomere-to-telomere (T2T) genome assembly for lettuce. T2T genome analysis revealed the unique genetic and epigenetic architectures of centromere repeats dominated by retrotransposons and satellites. The complete genome and annotation facilitate the identification of candidate disease resistance (NLR) genes induced during grey mold infection. The genomic resources, and biological insights into genetic and epigenetic landscape of centromeres not only advance lettuce research and breeding, but also propel the biology and evolution of centromeres across plant kingdom.

genomics↗

bioRxiv2024

Silicification of Cyanobacteria

The ability to use dissolved silicon has been found in various oceanic phytoplankton, including eukaryotic diatoms and prokaryotic cyanobacteria. While the silicification process in diatoms has been extensively studied, it is poorly known in cyanobacteria. In this study, the Cyanobacteria (Synechococcus) silicification and its evolutionary relationships of silicon-related proteins with different phytoplankton and algae were compared. Results showed that, compared to others, cyanobacteria have similar silicification proteins as diatoms. In detail, cyanobacteria and diatoms displayed three silicification-related proteins (SIT, Silaffins, and Pleuralins), while several genera showed one or two of them, suggesting that cyanobacteria might have developed a Si related mechanism earlier than the diatoms and other species. Our findings show that, despite cyanobacterias earlier silicon mechanism compared to others, they might not use efficient Si accumulation, perhaps adapting unique intracellular elemental variation for their cellular processes for growth potential.

evolutionary biology↗

bioRxiv2024

Improvement in Outcomes and Prevention of Multiple Organ Dysfunction Syndrome After Cardiac Arrest and Successful Cardiopulmonary Resuscitation by Systemic Administration of Bumetanide in Male Mice

BACKGROUNDCardiac arrest (CA) and successful cardiopulmonary resuscitation (CPR) cause post-CA brain injury (PCABI) and extracerebral multiple organ dysfunction (EMOD), leading to low survival and disability in resuscitated patients. The pathogenesis of PCABI is still poorly understood, and no therapeutic-related factors have been identified to improve survival and neurological outcomes to date. Bumetanide is a promising pharmaceutical intervention for some neurological disorders that have some common pathophysiology with PCABI, and it also exhibit systemic protective effects on vital organs under pathological conditions. This study aims to investigate the protective effects of bumetanide on PCABI and EMOD after CA/CPR, and uncover the pathogenesis and biomarkers of PCABI at protein level. METHODSWe generated a hyperkalemia-induced asystole CA/CPR mouse model with bumetanide/vehicle treatment after resuscitation. Survival, neurological outcome, functional outcome, key pathophysiological process underlying PCABI, and injury level of EMOD were evaluated. Proteomics analysis of cerebral cortex was performed for investigating mechanisms of PCABI. RESULTSBumetanide significantly improved outcomes after CA/CPR and reduced the main pathophysiological processes of PCABI, including seizures, neurodegeneration, neuroinflammation, decreased cerebral blood flow, blood-brain barrier disruption, and oxidative stress. CA/CPR-induced injury in heart, lung, liver, kidney, spleen, adrenal gland, spinal cord, pennis, and urinary bladder were also alleviated by bumetanide. Proteomic study and experimental verification identified LCN2/NGAL is a potential biomarker for early neuroprognostication and has association with PCABI severity. CONCLUSIONSSystemic administration of bumetanide improved outcomes and prevented multiple organ dysfunction after CA/CPR. LCN2/NGAL is a novel biomarker for early neuroprognostication at 24 hours after CA/CPR. Clinical PerspectiveO_LIWhat Is New? O_LIPost-resuscitation bumetanide treatment could improve outcomes and prevent brain injury and extracerebral multiple organ dysfunction after hyperkalemia-induced asystole cardiac arrest in mice. C_LIO_LINeuronal subpopulations in cerebral cortex were selectively vulnerable, and all major organs had obvious tissue damage with inflammatory cell infiltration and tissue edema after resuscitation. C_LIO_LIThis the first study to identify the pathogenesis and biomarkers of post-cardiac arrest brain injury with proteomic studies, and LCN2/NGAL had a strong and graded association with pathogenesis of PCABI, which could be a marker for monitoring and neuroprognostication. C_LI C_LIO_LIWhat Are the Clinical Implications? O_LIBumetanide may be a novel pharmacological therapy to improve survival and neurological outcomes in post-resuscitation care, and cerebral-specific quantification of LCN2/NGAL could be used for early neuroprognostication at 24 hours after cardiac arrest. C_LIO_LIExtracerebral multiple organ injury is common and severe after resuscitation, which needs to be given more attention in clinical management. C_LI C_LI

physiology↗

bioRxiv2024

Characterization of the mesendoderm progenitors in the gastrulating mouse embryo

A population of putative mesendoderm progenitor cells that can contribute cellular descendants to both mesoderm and endoderm lineages is identified. These progenitor cells are localized to the anterior primitive streak and the adjacent epiblast of E7.0-E7.5 mid-to late-gastrula stage embryos. Lineage tracing in vivo revealed that putative mesendoderm progenitors that are marked by Mixl1 and Mesp1 activity contribute descendants to the endoderm layer. Analysis of the role of Mixl1 transcription factor in endoderm differentiation of the mouse epiblast stem cells revealed the choice for endoderm or mesoderm cell fate depends on the timing of activation of Mixl1 upon exit from pluripotency, suggesting Mixl1 function may underpin the divergence of the mesendoderm progenitor to mesoderm and endoderm lineages. The knowledge gained on the spatial, temporal, and lineage attribute of mesendoderm progenitors enriches our mechanistic understanding of germ layer allocation and endoderm differentiation of mesendoderm progenitor in embryonic development and lineage allocation of primed state pluripotent stem cells in vitro.

developmental biology↗

bioRxiv2024

Curved light sheet microscopy for centimeter-scale cleared tissues imaging

Imaging large cleared tissues requires scaling the throughput of imaging techniques. Here we introduce curved light sheet microscope to perform optical sectioning with curved light sheets. This concept addresses the long-standing field curvature problem and lowers the barriers in designing high-throughput objectives. Leveraging a customized objective, the curved light sheet microscope achieves diffraction-limited resolution (1.0 m laterally and 2.5 m axially) and uniform contrast over a field of view of more than 1 x 1 cm2 and is compatible with various tissue clearing techniques. Imaging an entire intact cleared mouse brain at 0.625 x 0.625 x 1.25 m3 voxel size takes less than 3 hours and image tiling is not required. We share full optics description of the objective and report imaging neuronal and vascular networks and tracing brain-wide long-distance axonal projections in intact mouse brains.

bioengineering↗

bioRxiv2024

RAG suppresses group 2 innate lymphoid cells

Antigen specificity is the central trait distinguishing adaptive from innate immune function. Assembly of antigen-specific T cell and B cell receptors occurs through V(D)J recombination mediated by the Recombinase Activating Gene endonucleases RAG1 and RAG2 (collectively called RAG). In the absence of RAG, mature T and B cells do not develop and thus RAG is critically associated with adaptive immune function. In addition to adaptive T helper 2 (Th2) cells, group 2 innate lymphoid cells (ILC2s) contribute to type 2 immune responses by producing cytokines like Interleukin-5 (IL-5) and IL-13. Although it has been reported that RAG expression modulates the function of innate natural killer (NK) cells, whether other innate immune cells such as ILC2s are affected by RAG remains unclear. We find that in RAG-deficient mice, ILC2 populations expand and produce increased IL-5 and IL-13 at steady state and contribute to increased inflammation in atopic dermatitis (AD)-like disease. Further, we show that RAG modulates ILC2 function in a cell-intrinsic manner independent of the absence or presence of adaptive T and B lymphocytes. Lastly, employing multiomic single cell analyses of RAG1 lineage-traced cells, we identify key transcriptional and epigenomic ILC2 functional programs that are suppressed by a history of RAG expression. Collectively, our data reveal a novel role for RAG in modulating innate type 2 immunity through suppression of ILC2s.

immunology↗

bioRxiv2024

Uncovering critical transitions and molecule mechanisms in disease progressions using Gaussian graphical optimal transport

Understanding disease progression is crucial for detecting critical transitions and finding trigger molecules, facilitating early diagnosis interventions. However, the high dimensionality of data and the lack of aligned samples across disease stages have posed challenges in addressing these tasks. We present a novel framework, Gaussian Graphical Optimal Transport (GGOT), for analyzing disease progressions. The proposed GGOT uses Gaussian graphical models, incorporating protein interaction networks, to characterize the data distributions at different disease stages. Then we use population-level optimal transport to calculate the Wasserstein distances and transport maps between stages, enabling us to detect critical transitions. By analyzing the per-molecule transport distance, we quantify the importance of each molecule and identify trigger molecules. Moreover, GGOT predicts the occurrence of critical transitions in unseen samples and visualizes the disease progression process. We apply GGOT to the simulation dataset and six disease datasets with varying disease progression rates, to show its effectiveness for detecting critical transitions and identifying trigger molecules.

bioinformatics↗

bioRxiv2024

Droplet Hi-C for Fast and Scalable Profiling of Chromatin Architecture in Single Cells

Comprehensive analysis of chromatin architecture is crucial for understanding the gene regulatory programs during development and in disease pathogenesis, yet current methods often inadequately address the unique challenges presented by analysis of heterogeneous tissue samples. Here, we introduce Droplet Hi-C, which employs a commercial microfluidic device for high-throughput, single-cell chromatin conformation profiling in droplets. Using Droplet Hi-C, we mapped the chromatin architecture at single-cell resolution from the mouse cortex and analyzed gene regulatory programs in major cortical cell types. Additionally, we used this technique to detect copy number variation (CNV), structural variations (SVs) and extrachromosomal DNA (ecDNA) in cancer cells, revealing clonal dynamics and other oncogenic events during treatment. We further refined this technique to allow for joint profiling of chromatin architecture and transcriptome in single cells, facilitating a more comprehensive exploration of the links between chromatin architecture and gene expression in both normal tissues and tumors. Thus, Droplet Hi-C not only addresses critical gaps in chromatin analysis of heterogeneous tissues but also emerges as a versatile tool enhancing our understanding of gene regulation in health and disease.

genomics↗

bioRxiv2024

The Glycolytic Metabolite Methylglyoxal Covalently Inactivates the NLRP3 Inflammasome.

The NLRP3 inflammasome promotes inflammation in disease, yet the full repertoire of mechanisms regulating its activity are not well delineated. Among established regulatory mechanisms, covalent modification of NLRP3 has emerged as a common route for pharmacological inactivation of this protein. Here, we show that inhibition of the glycolytic enzyme PGK1 results in the accumulation of methylglyoxal, a reactive metabolite whose increased levels decrease NLRP3 assembly and inflammatory signaling in cells. We find that methylglyoxal inactivates NLRP3 via a non-enzymatic, covalent crosslinking-based mechanism, promoting inter- and intra-protein MICA posttranslational linkages within NLRP3. This work establishes NLRP3 as capable of sensing a host of electrophilic chemicals, both exogenous small molecules and endogenous reactive metabolites, and suggests a mechanism by which glycolytic flux can moderate the activation status of a central inflammatory signaling pathway.

cell biology↗

bioRxiv2024

Unlocking TAS2R14 activation through intricate multi-ligand binding networks

Bitter taste receptors, particularly TAS2R14, play central roles in discerning a wide array of bitter substances, ranging from dietary components to pharmaceutical agents1-3. In addition, TAS2R14 has broad expression in non-gustatory tissues, suggesting its important roles in selective physiological processes and therapeutic potential4. Here, we present cryo-electron microcopy structures of TAS2R14 in complex with flufenamic acid and aristolochic acid, coupling with G protein subtypes gustducin and Gi. Distinct from most known GPCRs, agonists of TAS2R14 bind to multiple intracellular pockets. We highlight the cholesterol molecules occupying an upper transmembrane site, typically the orthosteric pocket in other GPCRs, also binding in the entrance to an intracellular agonist binding pocket, suggesting an endogenous modulatory function5. The structural and mutagenesis analysis illuminate the receptors broad-spectrum ligand recognition and activation via intricate multiple ligand-binding sites. Furthermore, we unveil the structural configuration of gustducin and its interaction with TAS2R14, as well as the coupling mode of Gi1. This investigation should be instrumental in advancing our knowledge of the mechanisms underlying bitter taste recognition and response, with broader relevance to sensory biology and pharmacology.

biophysics↗

bioRxiv2024

FLASH Irradiation Regulates IFN-β induction by mtDNA via Cytochrome c Leakage

Ultrahigh dose rate radiotherapy (FLASH-RT) is under intensive investigation for its biological benefits. The mechanisms underlying its ability to spare normal tissues while suppress tumor growth still remain controversial. Here we reveal that compared to the low dose rate electron irradiation (0.36 Gy/s), FLASH electron irradiation at 61 or 610 Gy/s enhances the cytochrome c leakage from mitochondria in human breast cells MCF-10A, which elicits substantial caspase activation, suppresses both the cytosolic mitochondrial DNA (mtDNA) accumulation and IFN-{beta} secretion. Besides, the deletion of mtDNA severely decreases the radiation-induced cGAS-STING activation. Conversely, the cytochrome c leakage in carcinoma cells MDA-MB-231 post electron irradiation is limited, especially for the case of FLASH irradiation, resulting in less cytosolic cytochrome c but stronger cGAS-STING activation than those in MCF-10A cells. The enhanced difference of cytochrome c leakage between cancer cells and normal cells post FLASH irradiation indicates a potential mechanism of FLASH effect by regulating the apoptotic and inflammatory pathway.

biophysics↗

bioRxiv2024

Anchor-Enhanced Bead Design for Reduced Oligonucleotide Synthesis Errors in Single-cell sequencing

Single-cell transcriptomics, reliant on the incorporation of barcodes and unique molecular identifiers (UMIs) into captured polyA+ mRNA, faces a significant challenge due to synthesis errors in oligonucleotide capture sequences. These inaccuracies, which are especially problematic in long-read sequencing, impair the precise identification of sequences and result in inaccuracies in UMI deduplication. To mitigate this issue, we have modified the oligonucleotide capture design, which integrates an interposed anchor between the barcode and UMI, and a V base anchor adjacent to the polyA capture region. This configuration is devised to ensure compatibility with both short and long-read sequencing technologies, facilitating improved UMI recovery and enhanced feature detection, thereby improving the efficacy of droplet-based sequencing methods.

molecular biology↗

bioRxiv2024

Spatiotemporal transcriptomic profiling reveals the dynamic immunological landscape of alveolar echinococcosis

Alveolar echinococcosis (AE) is caused by the invasive growth of the metacestodes of Echinococcus multilocularis (E. multilocularis). The early diagnosis, management, and treatment of AE remains challenging. Herein, we integrated bulk RNA-seq, scRNA-seq, and ST technologies to reveal the immune characteristics both spatially and chronologically in E. multilocularis infected mouse liver. An unprecedented high-resolution spatial atlas of the E. multilocularis infection foci was obtained, revealing the pivotal role of neutrophils, Spp1+ monocyte-derived macrophages (MoMFs), and fibroblasts in AE progression. We observed continuous recruitment of neutrophils and macrophages into the infected tissues, indicating prolonged immune stimulation by the growing metacestodes. However, their spatial distribution patterns and functions changed during the infection cause. At the early infection stage, Il1bhi neutrophils aggregated in the lesion displayed the highest pattern-recognition receptor activity and may kill the metacestodes through NETosis, but their death in the infection foci might also trigger immune suppression. Meanwhile, Spp1+ MoMFs attached to the protoscoleces to clear the infection. At the late infection stage, the neutrophils failed to infiltrate into the lesion although their continuous recruitment into the infected liver. Even though the Spp1+ MoMFs enclosing the microcysts of E. multilocularis may retain their pathogen-killing ability, they may also promote fibrosis and angiogenesis through interaction with fibroblasts. The pro- and anti-inflammatory phenotype balance of these immune cells may be associated with the transition of parasite control strategy from "active killing" to "negative segregation" by the host. Our findings identify key molecular traits involved in AE development, which may benefit the treatment of echinococcosis.

immunology↗

bioRxiv2024

Distinct Type 1 Immune Networks Underlie the Severity of Restrictive Lung Disease after COVID-19

The variable etiology of persistent breathlessness after COVID-19 have confounded efforts to decipher the immunopathology of lung sequelae. Here, we analyzed hundreds of cellular and molecular features in the context of discrete pulmonary phenotypes to define the systemic immune landscape of post-COVID lung disease. Cluster analysis of lung physiology measures highlighted two phenotypes of restrictive lung disease that differed by their impaired diffusion and severity of fibrosis. Machine learning revealed marked CCR5+CD95+ CD8+ T-cell perturbations in mild-to-moderate lung disease, but attenuated T-cell responses hallmarked by elevated CXCL13 in more severe disease. Distinct sets of cells, mediators, and autoantibodies distinguished each restrictive phenotype, and differed from those of patients without significant lung involvement. These differences were reflected in divergent T-cell-based type 1 networks according to severity of lung disease. Our findings, which provide an immunological basis for active lung injury versus advanced disease after COVID-19, might offer new targets for treatment.

immunology↗