Biology subjects

Subramanian, S.

Publications and source records attributed to Subramanian, S..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

Characterize Oral-to-Blood Microbial DNA Translocation in Individuals with Cocaine Use Disorder

BackgroundCocaine disrupts gut barriers in animal models, potentially enabling microbial translocation and inflammation in the periphery and central nervous system (CNS), but its direct role in inducing inflammation remains controversial. This study aimed to determine if the oral cavity is a source of circulating microbial DNA translocation in individuals with current cocaine use disorder (CUD). ResultsA cross-sectional case-control study was conducted, comparing CUD and demographically matched non-drug controls. Ten CUD (via smoking or vaping) and 24 controls provided paired saliva and blood samples. Microbial 16S rRNA V4 region was sequenced in isolated microbial DNA from saliva and plasma. Single-cell RNA sequencing (scRNAseq) was analyzed in human peripheral blood mononuclear cells. Saliva from CUD, but not plasma, exhibited reduced alpha diversity and altered beta diversity, characterized by enriched Streptococcus and depleted Fusobacterium, Neisseria, and other taxa relative to controls. Controls exhibited low to undetectable microbial translocation in plasma. By contrast, plasma displayed CUD-specific oral enrichment of several Streptococcal species and evidence of translocation into the bloodstream. S. parasanguinis, but not cocaine alone, induced IL-1{beta} and TNF- production in human primary monocytes in vitro. scRNAseq further revealed innate immune activation, impaired T cell function, and heightened susceptibility to infection in CUD. ConclusionsThis pilot study demonstrating that CUD via smoking or snorting exhibited oral microbial dysbiosis and selective oral-to-blood microbial translocation in vivo. These findings suggest that a compromised oral-to-blood barrier, rather than cocaine itself, promotes immune perturbations in CUD.

microbiology↗

bioRxiv2025

CTG clade-specific proteins of the RSC chromatin remodeling complex regulate cell cycle progression of a critical priority fungal pathogen, Candida albicans

The RSC and the homologous chromatin remodeling complexes are known to regulate cell cycle progression in various organisms, including Saccharomyces cerevisiae, Drosophila, and Homo sapiens. In this work, we characterized the role of two novel CTG clade-specific proteins (Nri1 and Nri2) of the RSC complex in the regulation of cell cycle progression in a critical priority fungal pathogen, Candida albicans. We observed that Nri1, alone or along with Nri2, regulates cell cycle progression at multiple stages. The nri1{Delta}/{Delta} and nri1{Delta}/{Delta} nri2{Delta}/{Delta} mutants exhibited transient cell cycle arrest, defective spindle morphology, and cytokinesis. Transcriptomic analysis supported these mutant phenotypes and indicated a broad role of Nri proteins in the cell cycle. From our results, we conclude that Nri proteins are crucial for C. albicans proliferation and fitness. ImportanceThe composition of the essential RSC chromatin remodeling complex exhibits species-specific divergence, harboring unique subunits with distinct functions. In this study, we report that two fungal CTG clade-specific proteins of the C. albicans RSC complex, namely Nri1 and Nri2 can promote C. albicans fitness through regulating its cell cycle progression at multiple stages. Fitness defect along with stressor sensitivity and differential expression of the genes regulating pathogenesis in the nri mutants indicate potentiality of the Nri proteins as anti-Candida drug targets.

cell biology↗

bioRxiv2025

Structures of two LarA-like nickel-pincer nucleotide cofactor-utilizing enzymes with a single catalytic histidine residue

The nickel pincer nucleotide (NPN) cofactor catalyzes the racemization/epimerization of -hydroxy acids in enzymes of the LarA family. The established proton-coupled hydride transfer mechanism requires two catalytic histidine residues that alternately act as general acids and general bases. Notably, however, a fraction of LarA homologs (LarAHs) lack one of the active site histidine residues, replacing it with an asparaginyl side chain that cannot participate in acid/base catalysis. Here, we investigated two such LarAHs and solved their cryo-electron microscopic structures with and without loaded NPN cofactor, respectively. The structures revealed a consistent octameric assembly that is unprecedented in the LarA family and unveiled a new set of active site residues that likely recognize and process substrates differently from those of the well-studied LarAHs. Genomic context analysis suggested their potential involvement in carbohydrate metabolism. Together, these findings lay the groundwork for expanding the breadth of reactions and the range of mechanisms of LarA enzymes.

biochemistry↗

bioRxiv2025

Expanding the Global Map of Protein Post Translational Modifications with Immunoaffinity Enrichment and nDIA Analysis on the Orbitrap Astral Mass Spectrometer

Post-translational modifications (PTMs) contribute greatly to the diversity of the human proteome by affecting protein structure, function, interactions, stability, localization, and more. The study of PTMs is essential to understand various cellular functions, disease mechanisms, and aid in the development of biomarkers and design of therapeutic targets. Owing to their diversity, dynamic nature, and low stoichiometry compared to unmodified proteome counterparts, the analysis of PTMs remains challenging. In this study, immunoaffinity enrichment of PTM peptides was combined with analysis using Data Dependent Acquisition (DDA) and narrow window Data Independent Acquisition (nDIA) on the Orbitrap Astral mass spectrometer (MS) as well as comparative analysis using the Orbitrap Fusion Lumos MS for Ubiquitination, Phosphorylation, Acetylation, Succinylation, and Methylation. Human cell line and mouse tissue samples at various input peptide amounts were immuno-enriched and mass spectrometry data was acquired on both instruments to assess depth of coverage and number of novel sites identified. The study identified a total of 88,731 unique ubiquitin sites, 64,397 phosphorylation sites (43,721 phosphoserine, 8,414 phosphothreonine and 12,262 phosphotyrosine), 11,629 acetylation, 5,272 succinylation and 1,461 mono-methylation sites. In half the acquisition time, nDIA analysis of immuno-enriched samples on Orbitrap Astral MS provided much greater depth of coverage for all PTMs compared to DDA analysis on Orbitrap Fusion Lumos MS, with up to 33-fold more PTM peptides identified and quantified. Overall, the data presented in this study demonstrates the need for enrichment for PTM detection and the utility of combining antibody-based peptide capture and nDIA on the Orbitrap Astral MS as powerful tools for discovery and profiling of protein post-translational modifications in cells and tissues.

biochemistry↗

bioRxiv2025

Stimulation modulates cell assemblies linked with gene networks in the human temporal cortex ex vivo

Deep brain stimulation of the temporal cortex can enhance learning and memory in the face of cognitive impairment. Despite the potential of such therapies, the neural and genetic mechanisms underlying the effect of stimulation on human brain circuits are not understood. To explicate direct mechanisms of neural modulation elicited by brain stimulation, we developed an ex vivo approach utilizing microelectrode array stimulation and recording of resected temporal cortex from neurosurgical patients. We find that stimulation preferentially increases firing rates in pyramidal cells compared to interneurons and also strengthens cell assemblies. Using single cell multiomics, we link the observed physiological changes to cell type-specific gene expression patterns. We detail gene regulatory networks that indicate preferential involvement of specific excitatory neuron subtypes and the response of non-neurons. We conclude that the overall impact of stimulation on the human temporal cortex is activation of specific excitatory neurons and enhanced cell assembly activity, and that these changes are supported by gene networks involving immediate early, synaptic, and ion channel genes. Our findings establish a foundation to identify targetable cell type-specific genetic signatures that may be harnessed for therapeutic benefit in future neuromodulation strategies.

neuroscience↗

bioRxiv2025

Cetuximab increases LGR5 expression and augments LGR5-targeting antibody-drug conjugate efficacy in patient-derived colorectal cancer models

Colorectal cancer (CRC) remains the second-leading cause of cancer-associated deaths, indicating an urgent need for improved therapeutic options. We previously generated antibody-drug conjugates (ADCs) targeting the cancer stem-like cell marker leucine-rich repeat-containing G protein-coupled receptor 5 (LGR5). However, tumor relapse due to LGR5 downregulation and suboptimal payload selection warranted strategies to improve ADC efficacy. Here we report cetuximab, an EGFR-targeting monoclonal antibody indicated for RASWT metastatic CRC, augments LGR5 expression independent of RAS/PIK3CA mutation status and promotes EGFR-LGR5 interactions. Furthermore, we describe the development of LGR5 ADCs incorporating a camptothecin-derived payload that is well-tolerated and significantly inhibits tumor growth. Importantly, cetuximab in combination with LGR5 ADCs results in enhanced tumor inhibition or regression versus single-agent treatment and extends survival in RASMUT patient-derived xenografts. These findings support growing evidence that ADC combination therapies may be more effective than monotherapies and suggests a broader clinical use for cetuximab in treating RASMUT CRC.

cancer biology↗

bioRxiv2025

Direct interoceptive input to the insular cortex shapes learned feeding behavior

The insular cortex (insula) is an interoceptive hub, which senses internal states such as hunger, thirst, pain, and emotions. Previous studies suggest that the insula directly senses internal states, but the mechanisms remain elusive. We identified a population of leptin receptor-positive cells with a unique morphology in the insula (INSLepR). Based on leptins known role in signaling adiposity, we hypothesized that INSLepR neurons detect internal states to regulate food intake and body weight. Accordingly, we found that intra-insula leptin administration or optogenetic stimulation of INSLepR neurons impacts feeding behavior. Moreover, INSLepR neuron activity encodes feeding bouts in an internal-state dependent manner, and leptin alters insula neural dynamics in response to feeding, while also reshaping the transcriptome. Taken together, our data supports a model for direct interoceptive input to the insula, in which INSLepR cells integrate adiposity level signals to regulate feeding and body weight in a learned manner.

neuroscience↗

bioRxiv2025

Alpha-1 Antitrypsin Overexpressing Mesenchymal Stem/Stromal Cells Reverses Type 1 Diabetes via Promoting Treg Function and CD8+ T cell exhaustion

Mesenchymal stem/stromal cell (MSC) therapy holds great promise as both a therapeutic option and as a biofactory, as cells produce therapeutic proteins to augment their efficacy in disease treatment. This study investigates the therapeutic effects and the mechanistic insights of alpha-1 antitrypsin overexpressing MSCs (AAT-MSCs) in diabetes prevention and treatment. A single infusion of AAT-MSCs not only delayed diabetes onset but reversed new-onset type 1 diabetes (T1D) in the nonobese diabetic (NOD) mice. Using single-cell RNA sequencing, flow cytometry, and functional analyses, we characterized the impact of AAT-MSCs on immune cells, particularly CD4+ and CD8+ T cells, in pancreatic lymph nodes (PLNs) and islets of NOD mice. AAT-MSCs enhanced the immunosuppressive function and the communication of regulatory T cells (Tregs) with other immune cells while reducing the numbers of T helper 1 (Th1) cells and CD8+ cytotoxic T cells. In vitro experiments further confirmed the capacity of AAT-MSCs to promote the proliferation of Tregs, which consequently fostered an exhausted phenotype in CD8+ T cells, thereby facilitating {beta} cell survival and potentially aiding in diabetes remission. Thus, our findings underscore the significant protective effects of AAT-MSCs, delineate their novel mechanistic insight on recipient immune cells, and provide evidence for the clinical application of AAT-MSCs in treating T1D.

cell biology↗

bioRxiv2025

Measuring the selective packaging of RNA molecules by viral coat proteins in cells

Some RNA viruses package their genomes with extraordinary selectivity, assembling protein capsids around their own viral RNA while excluding nearly all host RNA. How the assembling proteins distinguish viral RNA from host RNA is not fully understood, but RNA structure is thought to play a key role. To test this idea, we perform in-cellulo packaging experiments using bacteriophage MS2 coat proteins and a variety of RNA molecules in E. coli. In each experiment, plasmid-derived RNA molecules with a specified sequence compete against the cellular transcriptome for packaging by plasmid-derived coat proteins. Following this competition, we quantify the total amount and relative composition of the packaged RNA using electron microscopy, interferometric scattering microscopy, and high-throughput sequencing. By systematically varying the input RNA sequence and measuring changes in packaging outcomes, we are able to directly test competing models of selective packaging. Our results rule out a longstanding model in which selective packaging requires the well-known TR stem-loop, and instead support more recent models in which selectivity emerges from the collective interactions of multiple coat proteins and multiple stem-loops distributed across the RNA molecule. These findings establish a framework for understanding selective packaging in a range of natural viruses and virus-like particles, and lay the groundwork for engineering synthetic systems that package specific RNA cargoes. Significance StatementBacteriophage MS2 packages its RNA genome into protective protein shells called capsids while excluding nearly all host-cell RNA. Engineering synthetic capsids with similar selectivity could enable a broad range of RNA-based technologies, including CRISPR gene editing systems, mRNA vaccines, and other emerging RNA-based therapeutics. Our study shows that selective packaging in MS2 is not dictated by a single, high-affinity RNA-protein interaction but instead emerges from the collective interactions of multiple coat proteins and an ensemble of stem-loops distributed across the RNA molecule. By establishing these collective interactions as the basis of selectivity, our findings provide a foundation for engineering synthetic capsids capable of selectively packaging target RNAs for next-generation RNA-based technologies.

biophysics↗

bioRxiv2025

MyoBack: A Musculoskeletal Model of the Human Back with Integrated Exoskeleton

Given the challenges of real-life experimentation, musculoskeletal simulation models could become essential in biomedical research. This is especially critical for the human back, a key structure involved in daily movements, where modeling and simulation could streamline design and support the development of treatments and robotic rehabilitation techniques, such as exoskeletons. However, musculoskeletal simulation engines are computationally demanding and lack contact dynamics, restricting current models use in studying prolonged behaviors or optimizing system design while maintaining physiological accuracy. To overcome this limitation, this work proposes MyoBack, a human back model part of the MyoSuite framework relying on the physics engine MuJoCo. This model is derived from a physiologically accurate model built in the state-of-the-art musculoskeletal simulation software OpenSim and replicates the latters kinematic properties accurately, with some discrepancies regarding muscle dynamics stemming from engine differences. The MyoBack model was also validated empirically by integrating a passive back exoskeleton in simulation and comparing forces exerted on the back with values from experimental trials. Over different tasks, the model reproduced measured force progressions well, resulting in RMSE = 11% for a stoop and RMSE = 16% for a squat motion pattern relative to peak forces. The MyoBack model can be accessed here: https://github.com/rohwalia/MyoBack

bioengineering↗

bioRxiv2024

SMAD4 Mutation Drives Gut Microbiome Shifts Toward Tumor Progression in Colorectal Cancer

Colorectal cancer (CRC) progression is driven by a series of sequential mutations in key driver genes, yet the factors underpinning tumor advancement and metastasis remain incompletely understood. Mutations in TP53 and SMAD4, in particular, are associated with poor treatment response and enhanced CRC pathogenesis. Although gut microbiome dysbiosis is implicated in CRC initiation and inflammation, the interactions between the microbiome and specific CRC driver mutations, especially those promoting metastasis, are poorly defined. In this study, we used triple mutant (Apc, Kras, Tp53; AKP) and quadruple mutant (Apc, Kras, Tp53, Smad4; AKPS) organoid-based orthotopic mouse models of CRC to examine the impact of SMAD4 mutation on tumor progression, metastasis, and microbiome composition. AKP and AKPS organoids were endoscopically implanted into the colons of individually housed C57BL/6 mice, and fecal samples were collected weekly over an 8-week period. Our results reveal significant differences in metastatic potential and microbial community dynamics between the two tumor models. AKPS tumors exhibited metastasis to the lymph nodes, liver, and lungs, whereas AKP tumors remained confined to the colon. Longitudinal microbiome analysis showed shifts in microbial composition within each tumor model. Both AKP and AKPS models demonstrated enrichment of Faecalibaculum and a decrease in Dubosiella over time; however, additional shifts were observed with distinct taxa associated with late-stage tumors in each group. Notably, the AKPS model exhibited higher relative abundances of pro-inflammatory taxa, including Turicibacter, Romboutsia, and Akkermansia, suggesting that SMAD4 mutation promotes a more immunosuppressive and pro-metastatic microbiome profile. These findings underscore the role of SMAD4 in modulating the microbiome in a manner that favors CRC metastasis and suggests potential microbial targets for therapeutic intervention to slow CRC progression. This work provides new insights into the microbiomes role in CRC mutagenesis and metastasis, highlighting the interplay between host genetics and gut microbiota in driving cancer aggressiveness.

cancer biology↗

bioRxiv2024

Rates of evolution differ between cell types identified by single-cell RNAseq in threespine stickleback

Rates of evolutionary change vary by gene. While some broad gene categories are highly conserved with little divergence over time, others undergo continuous selection pressure and are highly divergent. Here, we combine single-cell RNA sequencing (scRNAseq) with evolutionary genomics to understand whether certain cell types exhibit faster evolutionary divergence (using their characteristic genes), than other types of cells. Merging scRNAseq with population genomic data, we show that cell types differ in the rate at which their characteristic genes evolve, as measured by allele frequency divergence among many populations (FST) and between species (dN/dS ratios). Neutrophils, B cells, and fibroblasts exhibit elevated FST at characteristic genes, while eosinophils in the intestine and thrombocytes in the head kidney exhibit lower FST than the average for 1000 random genes. Gene network centrality also differed between immune- and non-immune-associated genes, and closeness centrality was positively related to gene FST. These results highlight the value of merging single cell RNA sequencing technology with evolutionary population genomic data, and reveal that genes which define immune cell types exhibit especially rapid evolution.

evolutionary biology↗

bioRxiv2024

IFNγ initiates TLR9-dependent autoimmune hepatitis in DNase II deficient mice

Patients with biallelic hypomorphic mutation in DNASE2 develop systemic autoinflammation and early-onset liver fibrosis. Prior studies showed that Dnase2-/- Ifnar-/- double knockout (DKO) mice develop Type I IFN-independent liver inflammation, but immune mechanisms were unclear. We now show that DKO mice recapitulate many features of human autoimmune hepatitis (AIH), including periportal and interstitial inflammation and fibrosis and elevated ALT. Infiltrating cells include CD8+ tissue resident memory T cells, type I innate lymphoid cells, and inflammatory monocyte/macrophage cells that replace the Kupffer cell pool. Importantly, TLR9 expression by bone marrow-derived cells is required for the the development of AIH. TLR9 is highly expressed by inflammatory myeloid cells but not long-lived Kupffer cells. Furthermore, the initial recruitment of TLR9 expressing monocytes and subsequent activation of lymphocytes requires IFN{gamma} signaling. These findings highlight a critical role of feed forward loop between TLR9 expressing monocyte-lineage cells and IFNg producing lymphocytes in autoimmune hepatitis.

immunology↗

bioRxiv2024

A Comprehensive Methodological Framework for Anthropometric Head Shape Modeling Using Small Dataset

Detailed anthropometric characterization of complex shapes of human heads can ensure optimal fit, comfort, and effectiveness of head-mounted devices. However, there is a lack of a reliable and systematic approach for head shape classification and modeling for laboratory-based, small, occupation-specific datasets. Therefore, in this study, we proposed a streamlined framework comprising six steps--pre-processing, feature extraction, feature selection, clustering, shape modeling, and validation--for head shape classification and modeling. We collected 36 firefighter 3D head scans and implemented the framework. Different clustering techniques, such as k-means and k-medoids, were evaluated using the squared Euclidean distance of individual head shapes from their cluster centroid. Furthermore, five variations of NURBS and cubic spline methods were assessed to design the representative head shape of each cluster, and their accuracy was evaluated using mean square error (MSE) values. The clustering results indicated that k-means provide better metrics than k-medoids. Among the shape modeling methods, cubic spline least squares displayed the lowest MSE (0.70 cm2)and computational time (0.14 s), whereas NURBS least squares displayed the highest MSE (7.19 cm2). Overall, the framework with k-means clustering and cubic spline least squares modeling techniques proved to be the most efficient for small datasets.

bioengineering↗

bioRxiv2024

Self-growth suppression in Bradyrhizobium diazoefficiens is caused by a diffusible antagonist

Microbes in soil navigate interactions by recognizing kin, forming social groups, exhibiting antagonistic behavior, and engaging in competitive kin rivalry. Here, we investigated a novel phenomenon of self-growth suppression (sibling rivalry) observed in Bradyrhizobium diazoefficiens USDA 110. Swimming colonies of USDA 110 developed a distinct demarcation line and inter-colony zone when inoculated adjacent to each other. In addition to self, USDA 110 suppressed growth of other Bradyrhizobium strains and several other soil bacteria. We demonstrated that the phenomenon of sibling rivalry is due to growth suppression but not cell death. The cells in the inter-colony zone were culturable but have reduced respiratory activity, ATP levels and motility. The observed growth suppression was due to the presence of a diffusible effector compound. This effector was labile, preventing extraction, and identification, but it is unlikely a protein or a strong acid or base. This counterintuitive phenomenon of self-growth suppression suggests a strategic adaptation for conserving energy and resources in competitive soil environments. Bradyrhizobiums utilization of antagonism including self-growth suppression likely provides a competitive advantage for long-term success in soil ecosystems.

microbiology↗

bioRxiv2024

Cholestasis alters polarization and suppressor function of hepatic regulatory T cells.

Fibrosing cholangiopathies, including biliary atresia and primary sclerosing cholangitis, involve immune-mediated bile duct epithelial injury and hepatic bile acid (BA) retention (cholestasis). Regulatory T-cells (Tregs) can prevent auto-reactive lymphocyte activation, yet the effects of BA on this CD4 lymphocyte subset are unknown. Gene regulatory networks for hepatic CD4 lymphocytes in a murine cholestasis model revealed Tregs are polarized to Th17 during cholestasis. Following bile duct ligation, Stat3 deletion in CD4 lymphocytes preserved hepatic Treg responses. While pharmacological reduction of hepatic BA in MDR2-/- mice prompted Treg expansion and diminished liver injury, this improvement subsided with Treg depletion. A cluster of patients diagnosed with biliary atresia showed both increased hepatic Treg responses and improved 2-year native liver survival, supporting that Tregs might protect against neonatal bile duct obstruction. Together, these findings suggest liver BA determine Treg function and should be considered as a therapeutic target to restore protective hepatic immune responses.

immunology↗

bioRxiv2024

Managed honey bee colony losses and causes during the active beekeeping season 2022/2023 in nine Sub-Saharan African countries

This study reports for the first-time managed honey bee colony loss rates and associated risk factors during the active beekeeping season 2022/2023 in nine Sub-Saharan African countries, namely Kenya, Ethiopia, Rwanda, Uganda, Benin, Liberia, Nigeria, Cameroon and Democratic Republic of the Congo. The sustainability of bee swarm catches as a main honey bee colony source tool for operation expansion by African beekeepers was also evaluated in Kenya and Ethiopia. In this survey, the 1,786 interviewed beekeepers across these countries collectively managing 41,761 colonies registered an overall loss rate of 21.3%, which varied significantly among countries (from 9.7 to 45.3%) and hive types (from 10.6% in hives with movable frames to 17.9% in frameless hives). The perceived causes of losses in order of significance were issues beyond the beekeepers control (mainly theft, drought, and bushfire), absconding and pests (mainly wax moth, small and large hive beetles, ants and Varroa destructor mite), but this pattern varied greatly across countries. Among the management practices and characteristics, migratory operations and professional beekeepers experienced lower losses than stationary operations and semi-professionals and hobby beekeepers. Insights into the number of bee swarms caught revealed significant decreases in swarm availability over the past three years in Kenya. The opposite situation was observed in some regions of Ethiopia. These trends require further investigation. Overall, this comprehensive survey sheds light on the complexities and challenges beekeepers faced in Sub-Saharan Africa, pointing to the need for targeted interventions and sustained research to support the resilience and growth of the apicultural sector.

zoology↗

bioRxiv2024

Metabolic immaturity of newborns and breast milk bile acids are the central determinants of heightened neonatal vulnerability to norovirus diarrhea

Noroviruses are the leading global cause of acute gastroenteritis, responsible for 685 million annual cases. While all age groups are susceptible to noroviruses, children are vulnerable to more severe infections than adults, underscored by 200 million pediatric cases and up to 200,000 deaths in children annually. Understanding the basis for the increased vulnerability of young hosts is critical to developing effective treatments. The pathogenic outcome of any enteric virus infection is governed by a complex interplay between the virus, intestinal microbiota, and host immune factors. A central mediator in these complex relationships are host- and microbiota-derived metabolites. Noroviruses bind a specific class of metabolites, bile acids, which are produced by the host and then modified by commensal bacterial enzymes. Paradoxically, bile acids can have both proviral and antiviral roles during norovirus infections. Considering these opposing effects, the microbiota-regulated balance of the bile acid pool may be a key determinant of the pathogenic outcome of a norovirus infection. The bile acid pool in newborns is unique due to immaturity of host metabolic pathways and developing gut microbiota, which could underlie the vulnerability of these hosts to severe norovirus infections. Supporting this concept, we demonstrate herein that microbiota and their bile acid metabolites protect from severe norovirus diarrhea whereas host-derived bile acids promote disease. Remarkably, we also report that maternal bile acid metabolism determines neonatal susceptibility to norovirus diarrhea during breastfeeding by delivering proviral bile acids to the newborn. Finally, directed targeting of maternal and neonatal bile acid metabolism can protect the neonatal host from norovirus disease. Altogether, these data support the conclusion that metabolic immaturity in newborns and ingestion of proviral maternal metabolites in breast milk are the central determinants of heightened neonatal vulnerability to norovirus disease.

microbiology↗