Biology subjects

Sharon, E.

Publications and source records attributed to Sharon, E..

10 recordsLinked to original sources

bioRxiv2026

Uncoupling Drug and Microbiota Contributions to Chemotherapy-Induced Gut Toxicity

Cytotoxic chemotherapy remains a cornerstone of cancer treatment but is frequently limited by gastrointestinal toxicity associated with epithelial barrier disruption. Although chemotherapy profoundly perturbs the gut microbiota, it remains unclear whether these microbial alterations actively contribute to intestinal injury or merely reflect collateral tissue damage. Here, we dissect the respective contributions of direct drug toxicity and chemotherapy-induced dysbiosis to gut pathology using cytarabine (Ara-C), a chemotherapeutic agent associated with severe intestinal complications. We show that both Ara-C and post-Ara-C microbiota independently compromise intestinal barrier integrity. However, these effects arise through distinct host transcriptional programs: Whereas Ara-C directly induces interferon-associated inflammatory responses, post-Ara-C microbiota preferentially activate mucosal barrier defense pathways. Together, these findings identify chemotherapy-induced dysbiosis as an active driver of mucosal injury and provide a mechanistic rationale for microbiome-targeted strategies to mitigate treatment-associated toxicity.

microbiology↗

bioRxiv2025

Spatial Transcriptomics Identify T Cell-Driven Mechanisms of Kidney Damage in Immune Checkpoint Inhibitor-Associated Acute Interstitial Nephritis

IntroductionImmune checkpoint inhibitor-associated acute interstitial nephritis (ICI-AIN) is the most common finding on histopathology among patients with ICI-associated acute kidney injury (ICI-AKI). Patients with ICI-AIN often have T cell-dominant infiltration of the kidney and high tissue levels of CXCR3 ligands like CXCL9, 10, and 11; however, the mechanisms of inflammation in ICI-AIN are not well-understood. MethodsWe applied a sub-cellular spatial transcriptomics platform (Xenium Prime 5K) to compare the cellular composition of kidney biopsy tissue from patients with ICI-AIN with ICI-treated patients with acute tubular necrosis (ICI-ATN). ResultsAcross 8 kidney biopsy specimens (4 with ICI-AIN, 4 with ICI-ATN), we analyzed 332,000 cells, comprising kidney parenchymal cells and infiltrating immune cells. Using a spatially-aware cellular neighborhood-based classification, we identified cellular niches corresponding to each part of the nephron, in addition to unique fibrotic and inflammatory niches. Gene pathway analysis identified interferon-gamma (IFN-{gamma})/STAT1 signaling as strongly increased in ICI-AIN compared to ICI-ATN. While all inflammatory niches were overrepresented in ICI-AIN, CD8+ T cell infiltration and proinflammatory myeloid cells were the dominant immune niches. Spatial niche crosstalk analysis revealed that CD8+ T cell-derived IFN-{gamma} likely induced a proinflammatory program in myeloid cells, with increased production of CXCL9, 10, and 11. Furthermore, IFN-{gamma} signaling in ICI-AIN was associated with reduced oxidative phosphorylation in kidney tubular niches. ConclusionsSpatial transcriptomics reveal novel insights into key differences in the pathophysiology of ICI-AIN versus ICI-ATN. IFN-{gamma}-producing CD8+ T cells are likely key drivers of ICI-AIN and should be investigated as future therapeutic targets. Translational StatementSpatial transcriptomics may provide insight into differences in the cellular and spatial composition of immune checkpoint inhibitor-associated acute interstitial nephritis (ICI-AIN) and ICI-associated acute tubular necrosis (ICI-ATN). Using the novel Xenium 5K platform, we demonstrate that IFN-{gamma}-producing CD8+ T cells are central to the pathogenesis of ICI-AIN, and that CD8+ T cell-derived IFN-{gamma} likely induces a proinflammatory state in myeloid cells, with increased tissue production of CXCL9, 10, and 11. We then show that a reduction in oxidative phosphorylation and an IFN-{gamma}-driven influx of proinflammatory myeloid cells may further drive kidney damage in ICI-AIN. Many of these pathways represent potential druggable targets, and our findings may therefore inform future therapeutic approaches for ICI-AIN.

immunology↗

bioRxiv2025

CladeOScope-GSA: A Tool for Predicting Functional Gene Interactions via Phylogenetic Profiling

Understanding gene function and protein network dynamics is a key challenge in biology and human health. In the light of the exponential growth in genomic data, phylogenetic profiling methods became more powerful in analysing thousands of genomes to uncover evolutionary associations and predict functional interactions [1,2,4,13,14,16,18,23,24,26]. It is based on the well-supported hypothesis that genes that work together are subject to similar evolutionary pressures and therefore their conservation patterns across phylogeny are correlated. We introduce CladeOScope-GSA, a web-based tool designed for phylogeny-aware analysis of gene sets across extensive comparative genomics datasets. By integrating clade-focused normalized phylogenetic profiling (NPP) with interactive visualization, CladeOScope-GSA enables researchers to identify evolutionary patterns within user-defined gene sets. Building upon the infrastructure of the original CladeOScope visualization platform, the addition of statistical gene set analysis, expanded phylogenetic and genomic data, enhanced visualization, and improved statistical tools represent a significant advancement in the tools capabilities. We demonstrate its utility through case studies spanning 1905 species, showcasing how CladeOScope-GSA empowers researchers to extract biological insights from complex comparative datasets. The web tool is accessible at https://tabachlab.shinyapps.io/CladeOScope

evolutionary biology↗

bioRxiv2023

An experimental approach towards untangling the role of nature versus nurture in shaping the microbiome of social insects

The gut microbiota is intimately related to host wellbeing, in terms of physiology, immune function, and even social interactions. The strength of this relationship is dynamic, but the extent to which the microbiome is shaped by the identity of the host (nature) or its environment (nurture) remains largely unknown. Here we aimed to identify factors shaping the microbiomes of nursing workers and larvae of two Vespidae species, using a cross-species experimental design to control for effects of environment, host identity and their interactions. We found that the microbiome composition of adults depended principally on the environment. Conversely, larval microbiome composition differed more between host species, regardless of treatment. We also found distinct microbiota profiles between the two species, across life stages and independently. These findings further elucidate the complexity of the host-microbiome relationship shaped by the environment while retaining symbionts that benefit the host. These results suggest that holobiont evolution may have promoted the rise of social behavior in animals.

evolutionary biology↗

bioRxiv2023

A Pooled Cell Painting CRISPR Screening Platform Enables de novo Inference of Gene Function by Self-supervised Deep Learning

Pooled CRISPR screening has emerged as a powerful method of mapping gene functions thanks to its scalability, affordability, and robustness against well or plate-specific confounders present in array-based screening 1-6. Most pooled CRISPR screens assay for low dimensional phenotypes (e.g. fitness, fluorescent markers). Higher-dimensional assays such as perturb-seq are available but costly and only applicable to transcriptomics readouts 7-11. Recently, pooled optical screening, which combines pooled CRISPR screening and microscopy-based assays, has been demonstrated in the studies of the NFkB pathway, essential human genes, cytoskeletal organization and antiviral response 12-15. While the pooled optical screening methodology is scalable and information-rich, the applications thus far employ hypothesis-specific assays. Here, we enable hypothesis-free reverse genetic screening for generic morphological phenotypes by re-engineering the Cell Painting 16 technique to provide compatibility with pooled optical screening. We validated this technique using well-defined morphological genesets (124 genes), compared classical image analysis and self-supervised learning methods using a mechanism-of-action (MoA) library (300 genes), and performed discovery screening with a druggable genome library (1640 genes) 17. Across these three experiments we show that the combination of rich morphological data and deep learning allows gene networks to emerge without the need for target-specific biomarkers, leading to better discovery of gene functions.

genomics↗

bioRxiv2021

Diet-induced modifications to human microbiome reshape colonic homeostasis in irritable bowel syndrome

Changes in microbiome composition have been associated with a wide array of human diseases, turning the human microbiota into an attractive target for therapeutic intervention. Yet clinical translation of these findings requires the establishment of causative connections between specific microbial taxa and their functional impact on host tissues. Here, we colonized gut organ cultures with longitudinal microbiota samples collected from newly-diagnosed and therapy-naive irritable bowel syndrome (IBS) patients under low-FODMAP (fermentable Oligo-, Di-, Mono- saccharides and Polyols) diet. We show that post-diet microbiota regulates intestinal expression of inflammatory and neuro-muscular gene-sets. Specifically, we identify Bifidobacterium adolescentis as a diet-sensitive pathobiont that alters tight junction integrity and disrupts gut barrier functions. Collectively, we present a unique pathway discovery approach for mechanistic dissection and identification of functional diet-host-microbiota modules. Our data support the hypothesis that the gut microbiota mediates the beneficial effects of low-FODMAP diet, and reinforce the potential feasibility of microbiome based-therapies in IBS.

microbiology↗

bioRxiv2021

Cross-species identification of cancer-resistance associated genes uncovers their relevance to human cancer risk

Cancer is an evolutionarily conserved disease that occurs in a wide variety of species. We applied a comparative genomics approach to systematically characterize the genes whose conservation levels significantly correlates positively (PC) or negatively (NC) with a broad spectrum of cancer-resistance estimates, computed across almost 200 vertebrate species. PC genes are enriched in pathways relevant to tumor suppression including cell cycle, DNA repair, and immune response, while NC genes are enriched with a host of metabolic pathways. The conservation levels of the PC and NC genes in a species serve to build the first genomics-based predictor of its cancer resistance score. We find that PC genes are less tolerant to loss of function (LoF) mutations, are enriched in cancer driver genes and are associated with germline mutations that increase human cancer risk. Furthermore, their expression levels are associated with lifetime cancer risk across human tissues. Finally, their knockout in mice results in increased cancer incidence. In sum, we find that many genes associated with cancer resistance across species are implicated in human cancers, pointing to several additional candidate genes that may have a functional role in human cancer.

cancer biology↗

bioRxiv2020

Conservation motifs - a novel evolutionary-based classification of proteins

Cross-species protein conservation patterns, as directed by natural selection, are indicative of the interplay between protein function, protein-protein interaction and evolution. Since the beginning of the genomic era, proteins were characterized as either conserved or not conserved. This simple classification became archaic and cursory once data on protein orthologs became available for thousands of species. To enrich the language used to describe protein conservation patterns, and to understand their biological significance, we classified 20,294 human proteins against 1096 species. Analyses of the conservation patterns of human proteins in different eukaryotic clades yielded extremely variable and rich patterns that had never been characterized or studied before. Using mathematical classifications, we defined seven conservation motifs: Steps, Critical, Lately Developed, Plateau, Clade Loss, Trait Loss and Gain, which describe the evolution of human proteins. Overall, our work offers novel terms for conservation patterns and defines a new language intended to comprehensively describe protein evolution. This novel terminology enables the classification of proteins based on evolution, reveals aspects of protein evolution, and improves the understanding of protein functions.

evolutionary biology↗

bioRxiv2018

Narcolepsy risk loci are enriched in immune cells and suggest autoimmune modulation of the T cell receptor repertoire

Type 1 narcolepsy (T1N) is a neurological condition, in which the death of hypocretin-producing neurons in the lateral hypothalamus leads to excessive daytime sleepiness and symptoms of abnormal Rapid Eye Movement (REM) sleep. Known triggers for narcolepsy are influenza-A infection and associated immunization during the 2009 H1N1 influenza pandemic. Here, we genotyped all remaining consented narcolepsy cases worldwide and assembled this with the existing genotyped individuals. We used this multi-ethnic sample in genome wide association study (GWAS) to dissect disease mechanisms and interactions with environmental triggers (5,339 cases and 20,518 controls). Overall, we found significant associations with HLA (2 GWA significant subloci) and 11 other loci. Six of these other loci have been previously reported (TRA, TRB, CTSH, IFNAR1, ZNF365 and P2RY11) and five are new (PRF1, CD207, SIRPG, IL27 and ZFAND2A). Strikingly, in vaccination-related cases GWA significant effects were found in HLA, TRA, and in a novel variant near SIRPB1. Furthermore, IFNAR1 associated polymorphisms regulated dendritic cell response to influenza-A infection in vitro (p-value =1.92*10-25). A partitioned heritability analysis indicated specific enrichment of functional elements active in cytotoxic and helper T cells. Furthermore, functional analysis showed the genetic variants in TRA and TRB loci act as remarkable strong chain usage QTLs for TRAJ*24 (p-value = 0.0017), TRAJ*28 (p-value = 1.36*10-10) and TRBV*4-2 (p-value = 3.71*10-117). This was further validated in TCR sequencing of 60 narcolepsy cases and 60 DQB1*06:02 positive controls, where chain usage effects were further accentuated. Together these findings show that the autoimmune component in narcolepsy is defined by antigen presentation, mediated through specific T cell receptor chains, and modulated by influenza-A as a critical trigger.

genetics↗

bioRxiv2017

Deciphering Transcriptional Regulation of Human Core Promoters

Despite its pivotal role in regulating transcription, our understanding of core promoter function, architecture, and cis-regulatory elements is lacking. Here, we devised a highthroughput assay to quantify the activity of [~]15,000 fully designed core promoters that we integrated and expressed from a fixed location within the human genome. We find that core promoters drive transcription unidirectionally, and that sequences originating from promoters exhibit stronger activity than sequences originating from enhancers. Testing multiple combinations and distances of core promoter elements, we observe a positive effect of TATA and Initiator, a negative effect of BREu and BREd, and a 10bp periodicity in the optimal distance between the TATA and the Initiator. By comprehensively screening TF binding-sites, we show that site orientation has little effect, that the effect of binding site number on expression is factor-specific, and that there is a striking agreement between the effect of binding site multiplicity in our assay and the tendency of the TF to appear in homotypic clusters throughout the genome. Overall, our results systematically assay the elements that drive expression in core- and proximal-promoter regions and shed light on organization principles of regulatory regions in the human genome.

genomics↗