Biology subjects

Zhao, A.

Publications and source records attributed to Zhao, A..

At least 55 records · Page 3Linked to original sources

bioRxiv2023

Mast-Cell Expressed Membrane Protein-1 (MCEMP1) is expressed in classical monocytes and alveolar macrophages in Idiopathic Pulmonary Fibrosis and regulates cell chemotaxis, adhesion, and migration in a TGFβ dependent manner.

BackgroundMast-Cell Expressed Membrane Protein-1 (MCEMP1) is higher in Idiopathic Pulmonary Fibrosis (IPF) patients with increased risk of death and poor outcomes. Here we seek to establish the mechanistic role of MCEMP1 in pulmonary fibrosis. MethodsMCEMP1 expression was analyzed by single-cell RNA sequencing, immunofluorescence in Peripheral Blood Mononuclear Cells (PBMC) as well as in lung tissues from IPF patients and controls. Chromatin Immunoprecipitation (ChiP) and Proximity Ligation Assay (PLA) were used to study the transcriptional regulation of MCEMP1. Transient RNA interference and lentivirus transduction were used to knockdown and knock-in MCEMP1 in THP-1 cells to study chemotaxis, adhesion, and migration. Bulk RNA sequencing was used to identify the mechanisms by which MCEMP1 participates in monocyte function. Active RHO pull-down assay was used to validate bulk RNA sequencing results. ResultsWe identified increased MCEMP1 expression in classical monocytes and alveolar macrophages in IPF compared to controls. MCEMP1 was upregulated by TGF{beta} at the mRNA and protein levels in THP-1. TGF{beta}-mediated MCEMP1 upregulation results from the cooperation of SMAD3 and SP1 via concomitant binding to SMAD3/SP1 cis-regulatory elements within the MCEMP1 promoter. In terms of its function, we found that MCEMP1 regulates TGF{beta}-mediated monocyte chemotaxis, adhesion, and migration. 400 differentially expressed genes were found to increase after TGF{beta} stimulation of THP-1, further increased in MCEMP1 knock-in cells treated with TGF{beta} and decreased in MCEMP1 knockdown cells treated with TGF{beta}. GO annotation analysis of these genes showed enrichment for positive regulation of RHO GTPase activity and signal transduction. While TGF{beta} enhanced RHO GTPase activity in THP-1 cells, this effect was attenuated following MCEMP1 knockdown. ConclusionMCEMP1 is highly expressed in circulating classical monocytes and alveolar macrophages in IPF. MCEMP1 is regulated by TGF{beta} and participates in the chemotaxis, adhesion, and migration of circulating monocytes by modulating the effect of TGF{beta} in RHO activity. Our results suggest that MCEMP1 may regulate the migration and transition of monocytes to monocyte-derived alveolar macrophages during pulmonary fibrosis development and progression.

immunology↗

bioRxiv2023

Comprehensive multi-platform tyrosine kinase profiling reveals novel actionable FGFR aberrations across pediatric and AYA sarcomas

No targeted agents are approved for pediatric sarcomas. Tyrosine kinase (TK) inhibitors represent attractive therapeutic candidates, however, beyond rare TK-activating fusions or mutations, predictive biomarkers are lacking. RNA overexpression of TKs is more commonly observed in pediatric sarcomas, however, an unresolved question is when upregulated TK expression is associated with kinase activation and signaling dependence. We explored the TK molecular landscape of 107 sarcoma patients from the ZERO Childhood Cancer precision medicine program using whole genomic and transcriptomic sequencing. Phosphoproteomic analyses of tyrosine phosphorylation (pY) and functional in vitro and in vivo assays were also performed in cell lines and patient-derived xenografts (PDXs). Our integrated analysis shows that although novel genomic driver lesions are rare, they are present and therapeutically actionable in selected patients as exemplified by a novel LSM1-FGFR1 fusion identified in an osteosarcoma patient. We further show that in certain contexts, TK expression data can be used to indicate TK pathway activity and predict TK-inhibitor sensitivity. We exemplify the utility of FGFR-inhibitors in PAX3-FOXO1 fusion-positive rhabdomyosarcomas (FP-RMS) mediated by high FGFR4 and FGF8 RNA expression levels, and overt activation of FGFR4 (FGFR4_pY). We demonstrate marked tumor growth inhibition in all FP-RMS PDXs treated with single agent FGF401 (FGFR4-specific inhibitor) and single agent lenvatinib (multi-kinase FGFR-inhibitor). Clinical benefit of lenvatinib in a relapsed metastatic FP-RMS patient further exemplifies that FGFR-inhibitors deserve additional investigation in FP-RMS patients. Statement of significanceOur multi-omic interrogation of sarcomas in the ZERO Childhood Cancer program illustrates how an RNA-expression biomarker signature (FGFR4+/FGF8+) in association with FGFR4 activation identifies that PAX3-FOXO1-positive rhabdomyosarcoma patients could benefit from FGFR-inhibitors.

cancer biology↗

bioRxiv2023

Identifying the core genome of the nucleus-forming bacteriophage family and characterization of Erwinia phage RAY

We recently discovered that some bacteriophages establish a nucleus-like replication compartment (phage nucleus), but the core genes that define nucleus-based phage replication and their phylogenetic distribution were unknown. By studying phages that encode the major phage nucleus protein chimallin, including previously sequenced yet uncharacterized phages, we discovered that chimallin-encoding phages share a set of 72 highly conserved genes encoded within seven distinct gene blocks. Of these, 21 core genes are unique to this group, and all but one of these unique genes encode proteins of unknown function. We propose that phages with this core genome comprise a novel viral family we term Chimalliviridae. Fluorescence microscopy and cryo-electron tomography studies of Erwinia phage vB_EamM_RAY confirm that many of the key steps of nucleus-based replication encoded in the core genome are conserved among diverse chimalliviruses, and reveal that non-core components can confer intriguing variations on this replication mechanism. For instance, unlike previously studied nucleus-forming phages, RAY doesnt degrade the host genome, and its PhuZ homolog appears to form a five-stranded filament with a lumen. This work expands our understanding of phage nucleus and PhuZ spindle diversity and function, providing a roadmap for identifying key mechanisms underlying nucleus-based phage replication.

microbiology↗

bioRxiv2022

Eye structure shapes neuron function in Drosophila motion vision

Many animals rely on vision to navigate through their environment. The pattern of changes in the visual scene induced by self-motion is the optic flow1, which is first estimated in local patches by directionally selective (DS) neurons2-4. But how should the arrays of DS neurons, each responsive to motion in a preferred direction at a specific retinal position, be organized to support robust decoding of optic flow by downstream circuits? Understanding this global organization is challenging because it requires mapping fine, local features of neurons across the animals field of view3. In Drosophila, the asymmetric dendrites of the T4 and T5 DS neurons establish their preferred direction, making it possible to predict DS responses from anatomy4,5. Here we report that the preferred directions of fly DS neurons vary at different retinal positions and show that this spatial variation is established by the anatomy of the compound eye. To estimate the preferred directions across the visual field, we reconstructed hundreds of T4 neurons in a full brain EM volume6 and discovered unexpectedly stereotypical dendritic arborizations that are independent of location. We then used whole-head CT scans to map the viewing directions of all compound eye facets and found a non-uniform sampling of visual space that explains the spatial variation in preferred directions. Our findings show that the organization of preferred directions in the fly is largely determined by the compound eye, exposing an intimate and unexpected connection between the peripheral structure of the eye, functional properties of neurons deep in the brain, and the control of body movements.

neuroscience↗

bioRxiv2022

Strain dropouts reveal interactions that govern the metabolic output of the gut microbiome

The gut microbiome is complex, raising questions about the role of individual strains in the community. Here, we address this question by focusing on a functional unit within the community, the metabolic niche that controls bile acid 7-dehydroxylation. By constructing variants of a complex defined community in which we drop out strains that occupy this niche, we explore how interactions within and between niches shape community-level metabolism. Omitting both members of the niche, Clostridium scindens (Cs) and Clostridium hylemonae (Ch), eliminates secondary bile acid production and reshapes the community in a highly specific manner: eight strains go up or down in relative abundance by >100-fold, while the remaining strains are largely unaffected. In single-strain dropout communities (i.e., a strain swap within the niche), Cs and Ch reach the same relative abundance and dehydroxylate bile acids to a similar extent. However, the effect on strains in other niches differs markedly: Clostridium sporogenes increases >1000-fold in the {Delta}Cs but not {Delta}Ch dropout, reshaping the pool of microbiome-derived phenylalanine metabolites. Thus, strains that are functionally redundant within a niche can have widely varying impacts outside the niche, and a strain swap can ripple through the community in an unpredictable manner, resulting in a large impact on an unrelated community-level phenotype. Mice colonized by the {Delta}Cs{Delta}Ch community show decreased liver steatosis relative to those colonized by the {Delta}Ch community, demonstrating that a single strain from the microbiome can have a substantive impact on host physiology. Our work opens the door to the mechanistic studies of the role of an individual strain on community ecology and host physiology.

microbiology↗

bioRxiv2022

Hepatic AMPK activation in response to dynamic REDOX balance is a biomarker of exercise to improve blood glucose control

Antioxidant intervention is considered to inhibit reactive oxygen species (ROS) and alleviates hyperglycemia. Paradoxically, moderate exercise can produce ROS to improve diabetes. The exact redox mechanism of these two different approaches remains largely unclear. Here, by comparing exercise and antioxidants intervention on type 2 diabetic rats, we found moderate exercise upregulated compensatory antioxidant capability and reached a higher level of redox balance in the liver. In contrast, antioxidant intervention achieved a low-level redox balance by inhibiting oxidative stress. Both of these two interventions could promote glycolysis and aerobic oxidation mediated by hepatic AMPK activation, ameliorating diabetes. During exercise, different levels of ROS generated by exercise have differential regulations on the activity and expression of hepatic AMPK. Moderate exercise-derived ROS promoted hepatic AMPK glutathionylation activation. However, excess exercise increased oxidative damage, and inhibited the activity and expression of AMPK. Overall, our results illustrate that both exercise and antioxidant intervention improve blood glucose in diabetes by promoting redox balance, despite the levels of redox balance are different. Moreover, the activation and expression of AMPK could act as a biomarker to reflect the effective treatment range for diabetes. This finding provides theoretical evidence for the precise regulation of diabetes by antioxidants and exercise.

biochemistry↗

bioRxiv2022

Mapping the T cell repertoire to a complex gut bacterial community

Certain bacterial strains from the microbiome induce a potent, antigen-specific T cell response1-5. However, the specificity of microbiome-induced T cells has not been explored at the strain level across the gut community. Here, we colonize germ-free mice with a complex defined community (97 or 112 bacterial strains) and profile T cell responses to each strain individually. Unexpectedly, the pattern of T cell responses suggests that many T cells in the gut repertoire recognize multiple bacterial strains from the community. We constructed T cell hybridomas from 92 T cell receptor (TCR) clonotypes; by screening every strain in the community against each hybridoma, we find that nearly all of the bacteria-specific TCRs exhibit a one-to-many TCR-to-strain relationship, including 13 abundant TCR clonotypes that are polyspecific for 18 Firmicutes in the community. By screening three pooled bacterial genomic libraries against 13 pooled hybridomas, we discover that they share a single target: a conserved substrate-binding protein (SBP) from an ABC transport system. Treg and Th17 cells specific for an epitope from this protein are abundant in community-colonized and specific-pathogen-free mice. Our work reveals that T cell recognition of Firmicutes is focused on a widely conserved cell-surface antigen, opening the door to new therapeutic strategies in which colonist-specific immune responses are rationally altered or redirected.

immunology↗

bioRxiv2022

Chromosome-level Genomes Reveal the Genetic Basis of Descending Dysploidy and Sex Determination in Morus Plants

Multiple plant lineages have independently evolved sex chromosomes and variable karyotypes to maintain their sessile lifestyles through constant biological innovation. Morus notabilis, a dioecious mulberry species, has the fewest chromosomes among Morus spp., but the genetic basis of sex determination and karyotype evolution in this species have not been identified. Three high-quality genome assemblies generated of Morus spp. (including those of dioecious M. notabilis and Morus yunnanensis) were within the range 301-329 Mb in size which were grouped into six pseudochromosomes. Using a combination of genomic approaches, we showed that the putative ancestral karyotype of Morus was close to 14 protochromosomes, and that several chromosome fusion events resulted in descending dysploidy (2n = 2x = 12). We also characterized a [~]6.2-Mb sex-determining region on chromosome 3. The four potential male-specific genes, including a partially duplicated DNA helicase gene orthologue (named MSDH) and three Ty3_Gypsy long terminal repeat retrotransposons (named MSTG), were solely identified in the Y-linked area and considered to be strong candidate genes for sex determination or differentiation. Population genomic analysis showed that Guangdong accessions in China were genetically similar to Japanese accessions of mulberry. In addition, genomic areas containing selective sweeps that distinguish domesticated mulberry trees from wild populations in terms of flowering and disease resistance were identified. Our findings provide an important genetic resource for sex identification and molecular breeding in mulberry.

genomics↗

bioRxiv2022

TIGER: A Web Portal of Tumor Immunotherapy Gene Expression Resource

Immunotherapy is a promising cancer treatment method, but only a few patients benefit from it. Developing new immunotherapy strategies and effective biomarkers of response and resistance is urgent. Recent high-throughput bulk and single-cell gene expression profiling technologies have generated valuable resources in these regards. However, these resources are not well organized and systematic analysis is difficult. Here, we present TIGER, a tumor immunotherapy gene expression resource, which contains bulk transcriptome data of 1508 tumor samples with immunotherapy clinical outcome and 11,057 tumor/normal samples without immunotherapy clinical outcome, as well as single-cell transcriptome data of 2,116,945 immune cells of 655 samples. TIGER provides many useful modules to analyze the collected data and user-provided data. Using the resource in TIGER, we identified a tumor enriched subset of CD4+ T cells. Melanoma patients with higher signature score of this subset have significantly better response and survival under immunotherapy. We believe that TIGER will be helpful for understanding anti-tumor immunity mechanisms and discovering effective biomarkers. TIGER is freely accessible at http://tiger.canceromics.org/.

bioinformatics↗

bioRxiv2021

Reconstitution of the S. aureus agr quorum sensing pathway reveals a direct role for the integral membrane protease MroQ in pheromone biosynthesis

In Staphylococcus aureus, virulence is under the control of a quorum sensing (QS) circuit encoded in the accessory gene regulator (agr) genomic locus. Key to this pathogenic behavior is the production and signaling activity of a secreted pheromone, the autoinducing peptide (AIP), generated following the ribosomal synthesis and post-translational modification of a precursor polypeptide, AgrD, through two discrete cleavage steps. The integral membrane protease AgrB is known to catalyze the first processing event, generating the AIP biosynthetic intermediate, AgrD (1-32) thiolactone. However, the identity of the second protease in this biosynthetic pathway, which removes an N-terminal leader sequence, has remained ambiguous. Here, we show that MroQ, an integral membrane protease recently implicated in the agr response, is directly involved in AIP production. Genetic complementation and biochemical experiments reveal that MroQ proteolytic activity is required for AIP biosynthesis in agr specifiy groups -I and -II, but not group-III. Notably, as part of this effort, the biosynthesis and AIP-sensing arms of the QS circuit were reconstituted together in vitro. Our experiments also reveal the molecular features guiding MroQ cleavage activity, a critical factor in defining agr specificity group identity. Collectively, our study adds to the molecular understanding of the agr response and Staphylococcus aureus virulence.

microbiology↗

bioRxiv2021

Repression of Hypoxia-Inducible Factor-1 Contributes to Increased Mitochondrial Reactive Oxygen Species Production in Diabetes

BackgroundExcessive production of mitochondrial reactive oxygen species (ROS) is a central mechanism for the development of diabetes complications. Recently, hypoxia has been identified to play an additional pathogenic role in diabetes. In this study, we hypothesized that ROS overproduction was secondary to the impaired responses to hypoxia due to the inhibition of hypoxia-inducible factor-1 (HIF-1) by hyperglycemia. MethodsThe dynamic of ROS levels was analysed in the blood of healthy subjects and individuals with type 1 diabetes after exposure to hypoxia (ClinicalTrials.gov registration no. NCT02629406). The relation between HIF-1, glucose levels, ROS production and its functional consequences were analyzed in renal mIMCD-3 cells and in kidneys of mouse models of diabetes. ResultsExposure to hypoxia increased circulating ROS in subjects with diabetes, but not in subjects without diabetes. High glucose concentrations repressed HIF-1 both in hypoxic cells and in kidneys of animals with diabetes, through a HIF prolyl-hydroxylase (PHD) - dependent mechanism. The impaired HIF-1 signaling contributed to excess production of mitochondrial ROS through increased mitochondrial respiration that was mediated by Pyruvate dehydrogenase kinase 1 (PDK1) and was followed by functional consequences. The restoration of HIF-1 function attenuated ROS overproduction despite persistent hyperglycemia, and conferred protection against apoptosis and renal injury in diabetes. ConclusionsWe conclude that the repression of HIF-1 plays a central role in mitochondrial ROS overproduction in diabetes and is a potential therapeutic target for diabetic complications. These findings are highly significant and timely since the first PHD inhibitor that can activate HIF-1 has been newly approved for clinical use.

cell biology↗

bioRxiv2021

In vivo augmentation of a complex gut bacterial community

Efforts to model the human gut microbiome in mice have led to important insights into the mechanisms of host-microbe interactions. However, the model communities studied to date have been defined or complex but not both, limiting their utility. In accompanying work, we constructed a complex synthetic community (104 strains, hCom1) containing the most common taxa in the human gut microbiome. Here, we used an iterative experimental process to improve hCom1 by filling open metabolic and/or anatomical niches. When we colonized germ-free mice with hCom1 and then challenged it with a human fecal sample, the consortium exhibited surprising stability; 89% of the cells and 58% of the taxa derive from the original community, and the pre- and post-challenge communities share a similar overall structure. We used these data to construct a second version of the community, adding 22 strains that engrafted following fecal challenge and omitting 7 that dropped out (119 strains, hCom2). In gnotobiotic mice, hCom2 exhibited increased stability to fecal challenge and robust colonization resistance against pathogenic Escherichia coli. Mice colonized by hCom2 versus human feces are similar in terms of microbiota-derived metabolites, immune cell profile, and bacterial density in the gut, suggesting that this consortium is a prototype of a model system for the human gut microbiome.

microbiology↗

bioRxiv2021

Synaptic targets of functionally specialized R7 and R8 photoreceptors in the central eye and dorsal rim area of Drosophila

Color and polarization provide complementary information about the world and are detected by specialized photoreceptors. However, the downstream neural circuits that process these distinct modalities are incompletely understood in any animal. Using electron microscopy, we have systematically reconstructed the synaptic targets of the photoreceptors specialized to detect color and skylight polarization in Drosophila, and we have used light microscopy to confirm many of our findings. We identified known and novel downstream targets that are selective for different wavelengths or polarized light, and followed their projections to other areas in the optic lobes and the central brain. Our results revealed many synapses along the photoreceptor axons between brain regions, new pathways in the optic lobes, and spatially segregated projections to central brain regions. Strikingly, photoreceptors in the polarization-sensitive dorsal rim area target fewer cell types, and lack strong connections to the lobula, a neuropil involved in color processing. Our reconstruction identifies shared wiring and modality-specific specializations for color and polarization vision, and provides a comprehensive view of the first steps of the pathways processing color and polarized light inputs.

neuroscience↗

bioRxiv2021

Identification of Human CD4+ Sub-population of Resident Cardiac Fibroblasts Linked to Inflammation-Mediated Cardiac Fibrosis

Infiltration with inflammatory T-cells and accumulation of cardiac myofibroblasts are hallmarks of cardiac fibrosis and maladaptive remodeling. The origin, identity, and functions of the resident cardiac cells involved in this process are, however, unclear. To determine the identity of cells contained in regions exhibiting fibrosis, mass cytometry profiling was performed using resident human ventricular cardiac fibroblasts and right ventricle autopsy tissues from individuals diagnosed with pulmonary hypertension and SUGEN/hypoxia rats. Results showed that a subpopulation of resident myocardial fibroblasts expresses increased levels of CD4+, a helper T-cell surface marker, in addition to mesenchymal markers in humans and rats. Characterization of the resident cardiac fibroblast subpopulation, both structurally and functionally, using transcriptome and secretome analysis of the secreted cytokines, chemokines, proteins, and metabolites, evidenced that IL-1{beta} induces a phenotypic switch of human cardiac fibroblasts from mesenchymal to CD4+ lymphoidal lineage in vitro. RNA sequencing (RNA-seq) analysis of FACS-sorted CD4-expressing cardiac fibroblasts further revealed that the transcriptome of such IL-1{beta}-induced CD4+ fibroblast population exhibited classical lymphoidal and stem cell-like signatures. Lastly, reversal of cell clustering, phosphorylation of MAPK p38 and NF-{kappa}B p65, and phenotypic switching was achieved with the administration of an IL-1R antagonist. In conclusion, we have identified a subpopulation of cardiac fibroblasts which exhibits structural and functional attributes of both mesenchymal and lymphoid cells which is induced by IL-1{beta}-IL-1R-NFkB pathway for differentiation of cardiac fibroblast cells. These data suggest that cardiac fibroblast transdifferentiation during inflammation may form the basis for maladaptive remodeling during myocardial fibrosis.

cell biology↗

bioRxiv2020

A bacterial effector uncovers a metabolic pathway involved in resistance to bacterial wilt disease

Bacterial wilt caused by the soil-borne pathogen Ralstonia solanacearum is a devastating disease worldwide. Upon plant colonization, R. solanacearum replicates massively, causing plant wilting and death; collapsed infected tissues then serve as a source of inoculum. In this work, we show that the metabolic pathway mediated by pyruvate decarboxylases (PDCs), activated in response to low oxygen and involved in drought stress tolerance, contributes to resistance against bacterial wilt disease. Arabidopsis and tomato plants with deficient PDC activity are more susceptible to bacterial wilt, and treatment with either pyruvic acid or acetic acid (substrate and product of the PDC pathway, respectively) enhances resistance. An effector protein secreted by R. solanacearum, RipAK, interacts with PDCs and inhibits their oligomerisation and enzymatic activity. This work reveals a metabolic pathway involved in resistance to biotic and abiotic stresses, and a bacterial virulence strategy to promote disease and the completion of the pathogenic life cycle.

plant biology↗

bioRxiv2020

Caloric Restriction Remodels Energy Metabolic Pathways of Gut Microbiota and Promotes Host Autophagy

Calorie restriction (CR) can improve the metabolic balance of adults and elevate the relative abundance of probiotic bacteria in the gut while promoting longevity. However, the interaction between remodeled intestinal flora and metabolic improvement, as well as the mechanism for probiotic bacterial increase, are still unclear. In this study, using a metabolomics platform, we demonstrate for the first time, that CR leads to increased levels of malate and its related metabolites in biological samples. Next, we investigated the effects of CR on the gut microbial genome and the expression of mRNA related to energy metabolism which revealed a partially elevated TCA cycle and a subsequently promoted glyoxylate cycle, from which large amounts of malate can be produced to further impact malate related pathways in the host liver. Through the identification of key "hungry" metabolites produced by the gut microbiota that function in the promotion of autophagy in the host, further insight has been gained about a functional metabolic network important for both host-microbial symbiosis and maintenance of host health.

systems biology↗

bioRxiv2020

Multi-modal single cell analysis reveals brain immune landscape plasticity during aging and gut microbiota dysbiosis

The brain contains a diverse array of immune cell types. The phenotypic and functional plasticity of brain immune cells collectively contribute to brain tissue homeostasis and disease progression. Immune cell plasticity is profoundly influenced by local tissue microenvironment cues and systemic factors. Yet, the transcriptional mechanism by which systemic stimuli, such as aging and gut microbiota dysbiosis, reshape brain immune cell plasticity and homeostasis has not been fully delineated. Using Cellular Indexing of Transcriptomes and Epitopes by sequencing (CITE-seq), we analyzed compositional and transcriptional changes of the brain immune landscape in response to aging and gut dysbiosis. We first examined the discordance between canonical surface marker-defined immune cell types (Cell-ID) and their transcriptome signatures, which suggested transcriptional plasticity among immune cells despite sharing the same cell surface markers. Specifically, inflammatory and patrolling Ly6C+ monocytes were shifted predominantly to a pro-inflammatory transcriptional program in the aged brain, while brain ILCs shifted toward an ILC2 transcriptional profile. Finally, aging led to an increase of ILC-like cells expressing a T memory stemness (Tscm) signature in the brain. Antibiotics (ABX)-induced gut dysbiosis reduced the frequency of ILCs exhibiting Tscm-like properties in the aged mice, but not in the young mice. Enabled by high-resolution single-cell molecular phenotyping, our study revealed that systemic changes due to aging and gut dysbiosis prime the brain environment for an increased propensity for neuroinflammation, which provided insights into gut dysbiosis in age-related neurological diseases. Manuscript SummaryGolomb et al. performed Cellular Indexing of Transcriptomes and Epitopes by sequencing (CITE-seq) on immune cells from the brains of young and aged mice with and without antibiotics-induced gut dysbiosis. High resolution, single cell immunophenotyping enabled the dissection of extensive transcriptional plasticity of canonically identified monocytes and innate lymphoid cells (ILCs) in the aged brain. Through differential gene expression and trajectory inference analyses, the authors revealed tissue microenvironment-dependent cellular responses influenced by aging and gut dysbiosis that may potentiate neuroinflammatory diseases. Graphical Abstract O_FIG_DISPLAY_L [Figure 1] M_FIG_DISPLAY C_FIG_DISPLAY

immunology↗

bioRxiv2020

Connectivity establishes spatial readout of visual looming in a glomerulus lacking retinotopy

Visual systems can exploit spatial correlations in the visual scene by using retinotopy, the organizing principle by which neighboring cells encode neighboring spatial locations. However, retinotopy is often lost, such as when visual pathways are integrated with other sensory modalities. How is spatial information processed in the absence of retinotopy? Here, we focused on visual looming responsive LC6 cells in Drosophila, a population whose dendrites collectively tile the visual field, but whose axons form a single glomerulus--a structure lacking retinotopic organization--in the central brain. We identified multiple glomerulus neurons and found that they respond to looming in different portions of the visual field, unexpectedly preserving spatial information. Through EM reconstruction of all LC6 synaptic inputs to the glomerulus, we found that LC6 and downstream cell types form circuits within the glomerulus that establish spatial readout of visual features and contralateral suppression--mechanisms that transform visual information for behavioral control.

neuroscience↗