Biology subjects

Han, A.

Publications and source records attributed to Han, A..

35 records · Page 2Linked to original sources

bioRxiv2024

An amphiregulin reporter mouse enables transcriptional and clonal expansion analysis of reparative lung Treg cells

Regulatory T (Treg) cells are known to play critical roles in tissue repair via provision of growth factors such as amphiregulin (Areg). Areg-producing Treg cells have previously been difficult to study because of an inability to isolate live Areg-producing cells. In this report, we created a novel reporter mouse to detect Areg expression in live cells (AregThy1.1). We employed influenza A and bleomycin models of lung damage to sort Areg-producing and -non-producing Treg cells for transcriptomic analyses. Single cell RNA-seq revealed distinct subpopulations of Treg cells and allowed transcriptomic comparisons of damage-induced populations. Single cell TCR sequencing showed that Treg cell clonal expansion is biased towards Areg-producing Treg cells, and largely occurs within damage-induced subgroups. Gene module analysis revealed functional divergence of Treg cells into immunosuppression-oriented and tissue repair-oriented groups, leading to identification of candidate receptors for induction of repair activity in Treg cells. We tested these using an ex vivo assay for Treg cell-mediated tissue repair, identifying 4-1BB agonism as a novel mechanism for reparative activity induction. Overall, we demonstrate that the AregThy1.1mouse is a promising tool for investigating tissue repair activity in leukocytes.

immunology↗

bioRxiv2024

A nociceptive amygdala-striatal pathway for chronic pain aversion

The basolateral amygdala (BLA) is essential for assigning positive or negative valence to sensory stimuli. Noxious stimuli that cause pain are encoded by an ensemble of nociceptive BLA projection neurons (BLAnoci ensemble). However, the role of the BLAnoci ensemble in mediating behavior changes and the molecular signatures and downstream targets distinguishing this ensemble remain poorly understood. Here, we show that the same BLAnoci ensemble neurons are required for both acute and chronic neuropathic pain behavior. Using single nucleus RNA-sequencing, we characterized the effect of acute and chronic pain on the BLA and identified enrichment for genes with known functions in axonal and synaptic organization and pain perception. We thus examined the brain-wide targets of the BLAnoci ensemble and uncovered a previously undescribed nociceptive hotspot of the nucleus accumbens shell (NAcSh) that mirrors the stability and specificity of the BLAnoci ensemble and is recruited in chronic pain. Notably, BLAnoci ensemble axons transmit acute and neuropathic nociceptive information to the NAcSh, highlighting this nociceptive amygdala-striatal circuit as a unique pathway for affective-motivational responses across pain states.

neuroscience↗

bioRxiv2023

A microfluidic model of colonocyte-microbiota interaction mimicking the colorectal cancer microenvironment

Changes in the abundance of certain bacterial species within the colorectal microbiota correlate with colorectal cancer development. While carcinogenic mechanisms of single pathogenic bacteria have been characterized in vitro, limited tools are available to investigate interactions between pathogenic bacteria and both commensal microbiota and colonocytes in a physiologically relevant tumor microenvironment. To address this, we developed a microfluidic device that can be used to co-culture colonocytes and colorectal microbiota. The device was used to explore the effect of Fusobacterium nucleatum, an opportunistic pathogen associated with colorectal cancer development in humans, on colonocyte gene expression and microbiota composition. F. nucleatum altered the transcription of genes involved in cytokine production, epithelial-to-mesenchymal transition, and proliferation in colonocytes in a contact-independent manner; however, most of these effects were diminished by the presence of fecal microbiota. Interestingly, F. nucleatum significantly altered the abundance of multiple bacterial clades associated with mucosal immune responses and cancer development in the colon. Our results highlight the importance of evaluating the potential carcinogenic activity of pathogens in the context of a commensal microbiota, and the potential to discover novel inter-species microbial interactions in the colorectal cancer microenvironment.

bioengineering↗

bioRxiv2023

YiNet: An Integrated Traditional Chinese and Western Medicine Platform for Viral Infectious Diseases

Viral infectious diseases (VIDs) impose a heavy burden on global public health. Traditional Chinese medicine (TCM) has previously and is currently contributing to the prevention and treatment of infectious diseases. Omics and information technology enable the precise identification of virus characteristics, virus-host interactions and TCM mechanisms. In this study, we constructed the YiNet platform to better integrate the novel techniques and historical experience of TCM in infectious diseases. YiNet comprises three modules: knowledge base, database and toolkit. The YiNet knowledge base involves 43 VIDs, thereby systematically integrating the knowledge regarding viruses, host symptoms and TCM and Western medicine (commonly used chemical drugs, 6,899 herbs and 2,481 formulas). The YiNet database module includes multiple databases, comprising 57,340 genome sequences of 45,791 viral strains and 5,726 multi-omics datasets such as RNA-seq, ChIP-seq and ATAC-seq from different tissues and cell models. It also integrates 1,105 real-world TCM clinical cases. We adopted visual analysis tool to investigate pathogen-host-herb relationships. To explore pharmacological mechanisms for the core herbs, we added formula data mining and network pharmacology analysis pipelines and visualisation tools. YiNet can facilitate the mechanistic study of TCM and drug development for VIDs. The YiNet platform is publicly available at http://yinet.gene.ac/.

bioinformatics↗

bioRxiv2023

Individuals lack the capacity to accurately detect emotional piloerection

Piloerection (e.g., goosebumps) is an essential thermoregulatory and social signalling mechanism in non-human animals. While humans also experience piloerection--often being perceived as an indicator of profound emotional experiences--its comparatively less effective role in thermoregulation and communication might influence our capacity to monitor its occurrence. We present three studies (total N = 617) demonstrating participants general inability to detect their own piloerection events and their lack of awareness that piloerection occurs with a similar frequency on multiple anatomical locations. Participants over-reported piloerection events with only 31.8% coinciding with observable piloerection, a bias unrelated to piloerection intensity, anatomical location, heart rate variability, or interoceptive awareness. We also discovered a self-report bias for the forearm, contradicting the observation that piloerection occurs with equal frequency on multiple anatomical locations. Finally, there was low correspondence between self-reports of being "emotionally moved" and observed piloerection. These counterintuitive findings not only highlight a disconnect between an obvious physiological response and our capacity for self-monitoring, but they underscore a fascinating divergence between human and non-human species. While piloerection is vital in non-human organisms, the connection between piloerection and psychological experience in humans may be less significant than previously assumed, possibly due to its diminished evolutionary relevance. Statement of ImpactThis research reveals a striking dissociation between an obvious physiological response-- piloerection--and human capacity for self-perception. While this highlights the limitations of relying on self-report measures, it also underscores an important divergence between humans and non-human species. We propose that the relation between piloerection and psychological experience in humans is less pronounced than in other species, potentially due to its diminished role in human evolution.

animal behavior and cognition↗

bioRxiv2022

Analysis of the Drosophila Ajuba LIM protein defines functions for distinct LIM domains

The Ajuba LIM protein Jub mediates regulation of Hippo signaling by cytoskeletal tension through interaction with the kinase Warts, and also participates in feedback regulation of junctional tension through regulation of the cytohesin Steppke. To investigate how Jub interacts with and regulates its distinct partners, we investigated the ability of Jub proteins missing different combinations of its three LIM domains to rescue jub phenotypes and to interact with -catenin, Warts and Steppke. Multiple regions of Jub contribute to its ability to bind -catenin and to localize to adherens junctions in Drosophila wing imaginal discs. Co-immunoprecipitation experiments in cultured cells identified a specific requirement for LIM2 for binding to Warts. However, in vivo, both LIM1 and LIM2, but not LIM3, were required for regulation of wing growth, Yorkie activity, and Warts localization. Conversely, LIM2 and LIM3, but not LIM1, were required for regulation of cell shape and Steppke localization in vivo, and for maximal Steppke binding in co-immunoprecipitation experiments. These observations identify distinct functions for the different LIM domains of Jub.

cell biology↗

bioRxiv2022

Deep Learning-based Microbubble Localization for Ultrasound Localization Microscopy

Ultrasound localization microscopy (ULM) is an emerging vascular imaging technique that overcomes the resolution-penetration compromise of ultrasound imaging. Accurate and robust microbubble (MB) localization is essential for successful ULM. In this study, we present a deep learning (DL)- based localization technique that uses both Field-II simulation and in vivo chicken embryo chorioallantoic membrane (CAM) data for training. Both radiofrequency (RF) and in-phase quadrature (IQ) data were tested in this study. The simulation experiment shows that the proposed DL-based localization was able to reduce both missing MB localization rate and MB localization error. In general, RF data showed better performance than IQ. For the in vivo CAM study with high MB concentration, DL-based localization was able to reduce the vessel MB saturation time by more than 50% as compared to conventional localization. Additionally, we propose a DL-based framework for real-time visualization of the high-resolution microvasculature. The findings of the paper support the use of DL for more robust and faster MB localization, especially under high MB concentrations. The results indicate that further improvement could be achieved by incorporating temporal information of the MB data.

bioengineering↗

bioRxiv2021

Shiitake mycelium fermentation improves digestibility, nutritional value, flavor and functionality of plant proteins

Plant proteins can serve as inexpensive and environmentally friendly meat-replacements. However, poor taste characteristics and relatively low nutritional value prevent their full acceptance as meat substitutes. Fermentation of food has been historically used to improve the quality of foods. In this work we describe the improvement in digestibility, nutritional value, physical properties, and organoleptic characteristics, of a pea and rice protein concentrate blend through fermentation with shiitake mushroom mycelium. Ileal digestibility pig studies show increases in the DIAAS for the shiitake fermented pea and rice protein blend turning the blend into an "excellent source" of protein for humans. The fermentation also increases the solubility of the protein blend and reduces the content of the antinutrient compounds phytates and protease inhibitor. Mass spectrometry and sensory analyses of fermented protein blend indicates that fermentation leads to a reduction in off-note compounds substantially improving its organoleptic performance.

bioengineering↗

bioRxiv2021

Viral replication in human macrophages enhances an inflammatory cascade and interferon driven chronic COVID-19 in humanized mice.

Severe COVID-19 is characterized by persistent lung inflammation, inflammatory cytokine production, viral RNA, and sustained interferon (IFN) response all of which are recapitulated and required for pathology in the SARS-CoV-2 infected MISTRG6-hACE2 humanized mouse model of COVID-19 with a human immune system1-20. Blocking either viral replication with Remdesivir21-23 or the downstream IFN stimulated cascade with anti-IFNAR2 in vivo in the chronic stages of disease attenuated the overactive immune-inflammatory response, especially inflammatory macrophages. Here, we show SARS-CoV-2 infection and replication in lung-resident human macrophages is a critical driver of disease. In response to infection mediated by CD16 and ACE2 receptors, human macrophages activate inflammasomes, release IL-1 and IL-18 and undergo pyroptosis thereby contributing to the hyperinflammatory state of the lungs. Inflammasome activation and its accompanying inflammatory response is necessary for lung inflammation, as inhibition of the NLRP3 inflammasome pathway reverses chronic lung pathology. Remarkably, this same blockade of inflammasome activation leads to the release of infectious virus by the infected macrophages. Thus, inflammasomes oppose host infection by SARS-CoV-2 by production of inflammatory cytokines and suicide by pyroptosis to prevent a productive viral cycle.

immunology↗

bioRxiv2020

Sex differences in learning from exploration

Sex-based modulation of cognitive processes could set the stage for individual differences in vulnerability to neuropsychiatric disorders. While value-based decision making processes in particular have been proposed to be influenced by sex differences, the overall correct performance in decision making tasks often show variable or minimal differences across sexes. Computational tools allow us to uncover latent variables that define different decision making approaches, even in animals with similar correct performance. Here, we quantify sex differences in mice in the latent variables underlying behavior in a classic value-based decision making task: a restless 2-armed bandit. While male and female mice had similar accuracy, they achieved this performance via different patterns of exploration. Male mice tended to make more exploratory choices overall, largely because they appeared to get "stuck" in exploration once they had started. Female mice tended to explore less, but learned more quickly during exploration. Together, these results suggest that sex exerts stronger influences on decision making during periods of learning and exploration than during stable choices. Exploration during decision making is altered in people diagnosed addictions, depression, and neurodevelopmental disabilities, pinpointing the neural mechanisms of exploration as a highly translational avenue for conferring sex-modulated vulnerability to neuropsychiatric diagnoses.

animal behavior and cognition↗

bioRxiv2020

Sub-second heat inactivation of coronavirus

Heat treatment denatures viral proteins that comprise the virion, making virus incapable of infecting a host. Coronavirus (CoV) virions contain single-stranded RNA genomes with a lipid envelope and 4 proteins, 3 of which are associated with the lipid envelope and thus are thought to be easily denatured by heat or surfactant-type chemicals. Prior studies have shown that a temperature of as low as 75 {degrees}C and treatment duration of 15 min can effectively inactivate CoV. The applicability of a CoV heat inactivation method greatly depends on the length of time of a heat treatment and the temperature needed to inactivate the virus. With the goal of finding conditions where sub-second heat exposure of CoV can sufficiently inactivate CoV, we designed and developed a simple system that can measure sub-second heat inactivation of CoV. The system is composed of capillary stainless-steel tubing immersed in a temperature-controlled oil bath followed by an ice bath, through which virus solution can be flowed at various speeds. Flowing virus solution at different speeds, along with a real-time temperature monitoring system, allows the virus to be accurately exposed to a desired temperature for various durations of time. Using mouse hepatitis virus (MHV), a beta-coronavirus, as a model system, we identified that 85.2 {degrees}C for 0.48 s exposure is sufficient to obtain > 5 Log10 reduction in viral titer (starting titer: 5 x 107 PFU/mL), and that when exposed to 83.4 {degrees}C for 0.95 s, the virus was completely inactivated (zero titer, > 6 Log10 reduction). IMPORTANCEThree coronaviruses (CoVs) have now caused global outbreaks within the past 20 years, with the COVID19 pandemic caused by SARS-CoV-2 still ongoing. Methods that can rapidly inactivate viruses, especially CoVs, can play critical roles in ensuring public safety and safeguarding personal health. Heat treatment of viruses to inactive them can be an efficient and inexpensive method, with the potential to be incorporated into various human-occupied spaces. In this work, a simple system that can heat-treat viruses for extremely short period was developed and utilized to show that sub-second exposure of CoV to heat is sufficient to inactivate CoV. This opens up the possibility of developing instruments and methods of disinfecting CoV in diverse settings, including rapid liquid disinfection and airborne virus disinfection. The developed method can also be broadly utilized to assess heat sensitivity of viruses other viral pathogens of interest and develop sub-second rapid heat inactivation approaches.

bioengineering↗

bioRxiv2020

The functional and phenotypic diversity of single T-cell infiltrates in human colorectal cancer as correlated with clinical outcome

Although degree of T-cell infiltration in CRC was shown to correlate with a positive prognosis, the contribution of phenotypically and functionally distinct T cell subtypes within tumors remains unclear. We analyzed 37,931 single T cells with respect to transcriptome, TCR sequence and 23 cell surface proteins, from tumors and adjacent normal colon of 16 patients. Our comprehensive analysis revealed two phenotypically distinct cytotoxic T cell populations within tumors, including positively prognostic effector memory cells and non-prognostic resident memory cells. These cytotoxic T cell infiltrates transitioned from effector memory to resident memory in a stage-dependent manner. We further defined several Treg subpopulations within tumors. While Tregs overall were associated with positive clinical outcomes, CD38+ peripherally-derived Tregs, phenotypically related to Th17 cells, correlated with poor outcomes independent of cancer stage. Thus, our data highlight the diversity of T cells in CRC and demonstrate the prognostic significance of distinct T cell subtypes, which could inform therapeutic strategies.

immunology↗

bioRxiv2020

Genotypic diversity and dynamic nomenclature of Parechovirus A

Human parechoviruses (PeV-A) can cause severe sepsis and neurological syndromes in neonates and children and are currently classified into 19 genotypes based on genetic divergence in the VP1 gene. However, the genotyping system has notable limitations including an arbitrary distance threshold and reliance on insufficiently robust phylogenetic reconstruction approaches leading to inconsistent genotype definitions. In order to improve the genotyping system, we investigated the molecular epidemiology of human parechoviruses, including the evolutionary history of the different PeV-A lineages as far as is possible. We found that PeV-A lineages suffer from severe substitution saturation in the VP1 gene which limit the inference of deep evolutionary timescales among the extant PeV-A and suggest that the degree of evolutionary divergence among current PeV-A lineages has been substantially underestimated, further confounding the current genotyping system. We propose an alternative nomenclature system based on robust, amino-acid level phylogenetic reconstruction and clustering with the PhyCLIP algorithm which delineates highly divergent currently designated genotypes more informatively. We also describe a dynamic nomenclature framework that combines PhyCLIPs progressive clustering with phylogenetic placement for genotype assignment.

evolutionary biology↗

bioRxiv2020

Conserved anti-inflammatory effects and sensing of butyrate in zebrafish

Short chain fatty acids (SCFAs) are produced by microbial fermentation of dietary fiber in the gut. Butyrate is a particularly important SCFA with anti-inflammatory properties and is generally present at lower levels in inflammatory diseases associated with gut microbiota dysbiosis in mammals. We aimed to determine if SCFAs are produced by the zebrafish microbiome and if SCFAs exert conserved effects on zebrafish immunity as an example of the non-mammalian vertebrate immune system. We demonstrate that bacterial communities from adult zebrafish intestines synthesize all three main SCFA in vitro, although SCFA were below our detectable limits in zebrafish intestines in vivo. Immersion in butyrate, but not acetate or propionate, reduced the recruitment of neutrophils and M1-type pro-inflammatory macrophages to wounds. We found conservation of butyrate sensing by neutrophils via orthologs of the hydroxycarboxylic acid receptor 1 (hcar1) gene. Neutrophils from Hcar1-depeleted embryos were no longer responsive to the anti-inflammatory effects of butyrate, while macrophage sensitivity to butyrate was independent of Hcar1. Our data demonstrate conservation of anti-inflammatory butyrate effects and identify the presence of a conserved molecular receptor in fish.

immunology↗

bioRxiv2020

The Druggable Genome as Seen from the Protein Data Bank

Almost twenty years after the human genome was sequenced, the wealth of data produced by the international human genome project has not translated into a significantly improved drug discovery enterprise. This is in part because small molecule modulators that could be used to explore the cellular function of their target proteins and to discover new therapeutic opportunities are only available for a limited portion of the human proteome. International efforts are underway to develop such chemical tools for a few, specific protein families, and a "Target 2035" call to enable, expand and federate these efforts towards a comprehensive chemical coverage of the druggable genome was recently announced. But what is the druggable genome? Here, we systematically review structures of human proteins bound to drug-like ligands available from the protein databank (PDB) and use ligand desolvation upon binding as a druggability metric to draw a landscape of the human druggable genome. We show that the vast majority of druggable protein families, including some highly populated and deeply associated with cancer according to genomic screens, are almost orphan of small molecule ligands, and propose a list of 46 druggable domains representing 3440 human proteins that could be the focus of large chemical probe discovery efforts.

bioinformatics↗

bioRxiv2018

Inferring putative transmission clusters with Phydelity

Current phylogenetic clustering approaches for identifying pathogen transmission clusters are limited by their dependency on arbitrarily-defined genetic distance thresholds for within-cluster divergence. Incomplete knowledge of a pathogens underlying dynamics often reduces the choice of distance threshold to an exploratory, ad-hoc exercise that is difficult to standardise across studies. Phydelity is a new tool for the identification of transmission clusters in pathogen phylogenies. It identifies groups of sequences that are more closely-related than the ensemble distribution of the phylogeny under a statistically-principled and phylogeny-informed framework, without the introduction of arbitrary distance thresholds. Relative to other distance threshold-based and model-based methods, Phydelity outputs clusters with higher purity and lower probability of misclassification in simulated phylogenies. Applying Phydelity to empirical datasets of hepatitis B and C virus infections showed that Phydelity identified clusters with better correspondence to individuals that are more likely to be linked by transmission events relative to other widely-used non-parametric phylogenetic clustering methods without the need for parameter calibration. Phydelity is generalisable to any pathogen and can be used to identify putative direct transmission events. Phydelity is freely available at https://github.com/alvinxhan/Phydelity.

bioinformatics↗

bioRxiv2018

Crowding tunes 3D collagen fibrils and reveals matrix regulation of cancer cell morphogenesis

It is well established that the collagenous extracellular matrix surrounding solid tumors significantly influences the dissemination of cancer cells. However, the underlying mechanisms remain poorly understood, in part because of a lack of methods to modulate collagen fibril topology in the presence of embedded cells. In this work, we develop a technique to tune the fibril architecture of cell-laden 3D collagen matrices using PEG as an inert molecular crowding agent. With this approach, we demonstrate that fibril length and pore size can be modulated independently of bulk collagen density and stiffness. Using live cell imaging and quantitative analysis, we show that matrices with long fibrils induce cell elongation and single cell migration, while shorter fibrils induce cell rounding, collective migration, and morphogenesis. We conclude that fibril architecture is an independent regulator of cancer cell phenotype and that cell shape and invasion strategy are functions of collagen fibril length.

bioengineering↗