Biology subjects

Alvarez, J.

Publications and source records attributed to Alvarez, J..

At least 19 recordsLinked to original sources

bioRxiv2026

A mosaic RBD-nanoparticle pan-sarbecovirus vaccine elicits nanobodies that target highly conserved epitopes

SARS-CoV-2, the virus that causes COVID-19, continually mutates, producing new variants of concern (VOCs). Substitutions in the SARS-CoV-2 spike protein receptor-binding domain (RBD) have resulted in reduced efficacies of vaccines and therapeutic monoclonal antibodies. Indeed, since the emergence of Omicron and earlier VOCs, most previously approved anti-RBD therapeutic monoclonal antibodies are no longer authorized as therapeutics. To address VOC substitutions effects on therapeutic antibody efficacy, we sought to identify single-domain nanobodies (VHHs) targeting RBD regions (class 4, class 1/4, portions of class 3 and class 5 RBD epitopes) that are more conserved across VOCs, reasoning that the smaller size of camelid nanobodies compared with conventional two-domain antibody combining sites would facilitate access to occluded RBD epitopes. We used a Beacon optofluidic platform to isolate and characterize single memory B cells from a llama immunized with a mosaic RBD-nanoparticle immunogen that elicits broad antibody responses across sarbecoviruses. Using multiplex binding assays, we identified nanobodies that bind to spike RBDs from diverse sarbecovirus strains. Competition ELISAs and crystal structures of VHH-RBD complexes showed that isolated nanobodies recognize broadly conserved epitopes, including those on the RBD that are inaccessible to analogous conventional two-domain antibodies. Promising VHH-Fcs neutralized SARS-CoV-2 variants of concern and zoonotic sarbecoviruses, demonstrating potential therapeutic utility for current and future outbreaks.

immunology↗

bioRxiv2026

Mitochondrial perturbation adapts the proteome from early to advanced immune responses

Dysregulated immunity, a hallmark of many human diseases, co-occurs with mitochondrial dysfunction and is commonly associated with misprimed primary immune signaling. While transcriptionally well-characterized, the impact of mitochondria on the host response at the protein level is less clear. Using in vitro and in vivo approaches including proteotranscriptomics, our data suggest that OXPHOS promotes expression of early, cell autonomous immune proteins whereas mitochondrial perturbation favors mediators of cell extrinsic responses like inflammation. This response is independent of immune cues, time-dependent, conserved, and occurs across tissues in mouse models of mitochondrial dysfunction. These data illustrate unappreciated roles for mitochondrial state in adapting host responses at the protein level, which have implications for complex disease etiology and the ancestral origins for eukaryotic immune sensing.

immunology↗

bioRxiv2026

High-throughput screen identifies a potent MCU activator boosting cardiac contractile bioenergetics

Mitochondrial Ca2+ uptake through the mitochondrial calcium uniporter complex (MCUc) couples intracellular Ca2+ signaling to energy metabolism and cellular function. Despite its physiological importance, potent and selective pharmacological activators of the MCU complex remain scarce, and existing compounds show modest specificity. Here, we screened 1,280 bioactive compounds and identified CGP7930 as a potent activator of mitochondrial Ca2+ uptake. Mechanistically, the compound required MICU1, but not MICU2, to exert its effects. Molecular docking, non-covalent interaction analysis, and site-directed mutagenesis identified Gln304 and Val307 in MICU1 as critical determinants of compound activity. In addition to directly stimulating MCU activity, CGP7930 increased mitochondria-endoplasmic reticulum contact sites, suggesting an additional mechanism to facilitate inter-organellar Ca2+ transfer. CGP7930 promoted Ca2+-dependent activation of mitochondrial energy metabolism in cardiomyocytes and boosted the contractile performance of the mice hearts. This effect was MCU-dependent, as hearts from MCU KO mice failed to increase the ventricular contraction force upon CGP7930 perfusion. Molecular docking, non-covalent interaction analysis, and site-directed mutagenesis identified Gln304 and Val307 in MICU1 as critical determinants of compound activity.

biochemistry↗

bioRxiv2026

Development of a metabolomics-based index to monitor dietary effects on chronic inflammation: The Dietary Metabolomics Inflammation Index

BackgroundThe Dietary Inflammatory Index (DII) is widely used to assess the inflammatory potential of diet, but it relies on self-reported dietary assessment and does not directly capture individual differences in metabolism as an intermediate connection to inflammation. High-resolution metabolomics provides objective measurements that complement dietary assessment to support precision nutrition to control inflammation. ObjectiveWe developed, tested, and applied a Dietary Metabolite Inflammatory Index (DMII) to assess diet-related chronic inflammation using metabolites measured by liquid chromatography-high-resolution mass spectrometry. MethodsDII was calculated using dietaryindex R package with Block Food Frequency Questionnaire (FFQ) data. To develop the DMII, chronic inflammation-related dietary metabolites corresponding to the DII food parameters were found through a literature review. Dietary metabolites were identified and quantified by authentic standards by our established laboratory procedures. DMII uses the same inflammatory effect scores as the DII. Three DMII versions were developed: concentration-based, median-based, and quintile-based DMII. Mean and standard deviation of 29 dietary metabolites were calculated by using 3025 human plasma samples from 3 studies. DMII was tested in the Center for Health Discovery and Well-Being cohort (CHDWB) and the Atlanta African American Maternal and Child cohort (ATLAA) using chronic inflammation biomarkers, including high-sensitivity C-reactive protein (hs-CRP), CRP, and IL-6. The median-based DMII was further applied to four Alzheimers disease metabolomics datasets as a proof-of-concept application. ResultsIn the CHDWB study, concentration-based DMII had a weak positive correlation with Block FFQ-derived DII and strongly correlated with median-based and quintile-based DMII. In the same study, all three DMII versions had significant positive correlations with hs-CRP and IL-6. In the ATLAA study, only concentration-based DMII was positively associated with CRP and IL-6. Higher median-based DMII was associated with higher odds of Alzheimers disease. ConclusionsDMII provides a metabolomics-based framework for assessing diet-related chronic inflammation using metabolomics data. This metabolomics approach may complement self-reported dietary assessment to use diet and nutrition to help protect against chronic disease linked to inflammation.

biochemistry↗

bioRxiv2026

Immune repertoire profiling reveals extensive clonal expansion of T and B cells in CXCL9-rich niches in sinonasal cancer

Sinonasal cancer (SNC) is a rare and aggressive head and neck cancer with limited therapeutic options and an incompletely defined immune microenvironment. Although histopathology remains central to clinical tumor evaluation, immune profiling typically requires tissue dissociation and therefore loses the spatial relationships that shape antitumor immunity. Here, we combined single-cell RNA-sequencing approaches, spatial transcriptomics and Spatial V(D)J, a technique we recently pioneered, to analyse the cellular, spatial, and clonal architecture of SNC. We found that SNC tumors were marked by a robust T cell infiltration, including substantial proportions of classical tissue resident memory (TRM) and exhausted (TExh) CD8+ T cells. This inflamed phenotype was accompanied by an immense infiltration of suppressive regulatory T (Treg) cells, which differentiated towards a Tbet+CXCR3+ phenotype. Spatially, expanded Treg, CD8 T and B cell clones concentrated within specialized peritumoral immune niches enriched for cancer-associated fibroblasts, CXCL9 tumor-associated macrophages and LAMP3IDO1 dendritic cells. T cell clones occupying these niches were clonally related to those infiltrating epithelial tumor regions, linking lymphoid hubs to the broader tumor immune response. Together, these data identify SNC as an inflamed but highly immunoregulatory tumor type and reveal a spatially organized clonal architecture in which suppressive and cytotoxic lymphocyte states coexist within CXCL9 myeloid niches.

immunology↗

bioRxiv2026

Placental prostaglandin signaling disrupts barrier integrity and relays an acute inflammatory signal to the fetus.

Maternal inflammation during pregnancy is a major risk factor for adverse neurodevelopmental outcomes, yet the mechanisms linking maternal immune activation (MIA) to placenta-fetal brain axis dysfunction remain unclear. Using a poly-(I:C) mouse model, we show that MIA rapidly disrupts placental-blood barrier (PBB) integrity by disrupting pericyte-endothelium coupling within 48 hours, leading to increased placental permeability detected by in vivo MRI. We identify a prostaglandin E2 (PGE2)-dependent pathway involving cyclooxygenase-2 (COX2) and prostaglandin E-synthase (mPGES1) as a key mediator of this effect. Pharmacological inhibition of COX2 prevented MIA-induced structural and functional changes. In vitro explant studies confirmed that PGE2 acts via the EP3 receptor to disrupt pericyte-endothelium interactions, while ex vivo perfusion demonstrated that in addition to its local effects on PBB structure, placenta-derived PGE2 enters the fetal circulation. Finally, similar vascular alterations were observed in human placentas from pregnancies with severe maternal inflammation. These findings reveal a conserved inflammatory mechanism that compromises PBB integrity and may relay signals to the fetal brain, highlighting potential therapeutic targets for neuroprotection during prenatal inflammation. One Sentence SummaryMaternal immune activation during pregnancy disrupts placental vascular integrity through a COX2-dependent prostaglandin E2 pathway, which compromises the placenta-blood barrier and relays inflammatory signals to the fetus, identifying potential therapeutic targets for neuroprotection.

developmental biology↗

bioRxiv2026

Fitness effects of antimicrobial resistance genes in changing environments

The evolutionary success of antimicrobial resistance (AMR) genes is generally seen as a trade-off between their function in the presence and their cost in the absence of antibiotics. Mobile integrons are genetic elements that recruit and disseminate dozens of AMR genes among Gram-negative pathogens. Here, we have measured the fitness effects of 136 integron genes conferring resistance against several antibiotic families. We have found a significant proportion having neutral and positive effects in the absence of antibiotics. We confirmed this using a mouse model, where we also observed cases of changes in the sign of fitness effects. This led us to unveil that oxygen availability modulates the cost of AMR genes. Using a stochastic model, we show that fluctuating aerobic/anaerobic conditions can rescue AMR genes in the absence of selective pressure. Here we provide a comprehensive analysis of the cost of AMR at the gene level challenging the traditional fitness-resistance trade-off hypothesis.

microbiology↗

bioRxiv2025

Mitochondrial redox homeostasis links organellar stress surveillance to germline and somatic integrity in Caenorhabditis elegans

Mitochondrial redox homeostasis is essential for cellular metabolism and organismal development. To investigate the consequences of disrupting redox homeostasis in this organelle in a metazoan organism, we generated a double mutant lacking mitochondrial glutathione reductase (gsr-1a) and thioredoxin reductase (trxr-2) genes in Caenorhabditis elegans. While gsr-1a or trxr-2 single mutants are phenotypically normal, double gsr-1a trxr-2 mutants displayed small body size, gonadal migration defects, reduced brood size, and prolonged egg-laying period, without developmental delay or lethality. Transcriptomic analysis revealed strong induction of ATFS-1-dependent stress and detoxification genes. Consistent with this, gsr-1a trxr-2 worms exhibited constitutive ATFS-1 nuclear localization and robust Phsp-6::gfp expression. Triple gsr-1a trxr-2; atfs-1 mutants were nonviable, demonstrating that unfolded protein response (UPRmt) activation is essential under mitochondrial redox stress. Despite the induction of a stress response at the transcriptional level, gsr-1a trxr-2 double mutants were not more resistant to oxidative or pathogen stressors. Moreover, these mutants maintained normal respiration, ATP and ROS production while displaying altered mitochondrial morphology in a tissue-specific manner, independent of mitophagy genes but dependent on mitochondrial fission or fusion machinery. Functionally, gsr-1a trxr-2 mutants showed impaired motility, reduced calcium uptake upon carbachol stimulation, enhanced hypodermal wound repair, and decreased fertilization efficiency associated with lower muscle exopher production. Overall, our data show that simultaneous loss of mitochondrial GSR-1a and TRXR-2 compromises growth, fertility and muscle performance and triggers a constitutive ATFS-1-dependent UPRmt that sustains viability revealing mitochondrial redox control as a core determinant of organismal proteostasis. HighlightsO_LIgsr-1a or trxr-2 single mutants have no overt phenotypes. C_LIO_LIgsr-1a trxr-2 double mutants are viable but show small size, gonad migration defects and reduced progeny. C_LIO_LILoss of both reductases in mitochondria triggers a constitutive ATFS-1-dependent UPRmt. C_LIO_LIATFS-1 is essential for gsr-1a trxr-2 worms survival. C_LIO_LIgsr-1a trxr-2 animals remodel mitochondrial morphology in a tissue-specific manner. C_LIO_LIgsr-1a trxr-2 double mutants exhibit impaired muscle and sperm function but enhanced wound healing. C_LI Graphical abstract (to be incorporated)

genetics↗

bioRxiv2025

Disruption of a six-nucleotide miRNA motif improves PKD1 dosage and ameliorates polycystic kidney disease

Disrupting microRNA interactions to restore protein expression from haploinsufficient genes offers a promising precision-therapy strategy for monogenic disorders. PKD1 heterozygosity underlies autosomal dominant polycystic kidney disease (ADPKD), a disorder affecting nearly 12 million people worldwide, where reduced PKD1 dosage drives progressive cyst formation and kidney failure. We previously identified a 55-bp cis-repressive element in the PKD1 3'UTR. Here, we define a six-nucleotide miR-17 seed match within this element that is sufficient to reproduce PKD1 repression. In vivo base substitution of this motif stabilizes Pkd1 mRNA and increases polycystin-1 (PC1) protein levels, producing a robust reduction in cyst growth and preservation of kidney function in mouse models. To therapeutically recapitulate this effect, we developed a steric-blocking oligonucleotide that occludes the motif, stabilizes PKD1 transcript levels, increases PC1 expression, and mitigates cyst-pathogenic events in both murine and patient-derived ADPKD cells. Together, these findings establish a minimal, targetable cis-regulatory motif and provide proof-of-concept for oligonucleotide-mediated PKD1 derepression, while offering a potentially generalizable strategy to restore other haploinsufficient genes.

genetics↗

bioRxiv2025

Antiviral and Anti-inflammatory Effects of Cannabidiol in HIV/SIV Infection

Persistent reservoirs and chronic immune activation are hallmarks of HIV, despite the effectiveness of antiretroviral therapy (ART) in suppressing viral replication. Here, we use rhesus macaques and primary and induced pluripotent stem cell (iPSC)-derived human immune cells to evaluate the virologic and immunologic consequences of cannabidiol (CBD) exposure during HIV/SIV infection. We show that CBD, in the absence of ART, suppresses viral replication and establishment of the viral reservoir to levels comparable with first-line therapies during acute SIV infection of rhesus macaques. This antiviral effect of CBD extended to in vitro HIV infection of human macrophages, T cells, and microglia. Immunologically, we observe CBD slowed CD4+ T cell decline and polarization, decreased CD14+CD16+ monocyte expansion, and reduced interferon-inducible cytokine release in rhesus macaques. We identify comparable effects on cytokine production with in vitro CBD treatment of human macrophages, T cells, and microglia. Importantly, we find CBD inhibits cytokines only when an immune response is elicited by HIV, suggesting it is not broadly immunosuppressive. Finally, we determine CBD regulates endocannabinoid receptors, modulators, and transporters and inhibits NF-{kappa}b and STAT1 activation when mediating its antiviral and anti-inflammatory effects. These findings show beneficial effects of CBD in laboratory models of untreated HIV, thus placebo-controlled clinical trials to evaluate the safety and effectiveness of adjunctive CBD use with ART is warranted.

microbiology↗

bioRxiv2025

Impact of sex and glial tau expression on heat shock protein induction in a Drosophila model of tauopathy

Heat shock proteins (Hsps) are central components of the cellular stress response and serve as the first line of defense against protein misfolding and aggregation. Disruption of this proteostasis network is a hallmark of neurodegenerative diseases, including tauopathies - a class of neurodegenerative diseases characterized by intracellular tau accumulation in neuronal and glial cells. Although specific Hsps are enriched in glial cells, and some have been shown to directly bind tau and influence its aggregation, the broader interplay between Hsps and tau remains poorly understood. In particular, it is unclear whether tau expression affects the heat shock response, and whether this interaction is modulated in a sex-specific fashion. Here, we used a Drosophila model of tauopathy to examine both inducible and constitutive Hsp expression in response to heat stress in the context of glial tau expression. We found that Hsp expression displays sexually dimorphic expression patterns at basal levels and in response to heat stress. Moreover, tau expression in glia disrupts the normal induction of specific heat shock proteins following heat stress. This work provides new insight into how tau interacts with the cellular stress response, and highlights sex-specific differences in Hsp regulation. Understanding these molecular connections is crucial to understanding how the presence of tau in glial cells influences the stress response, and potentially contributes to tauopathy pathogenesis.

neuroscience↗

bioRxiv2025

Cross-reactive sarbecovirus antibodies induced by mosaic RBD-nanoparticles

Broad immune responses are needed to mitigate viral evolution and escape. To induce antibodies against conserved receptor-binding domain (RBD) regions of SARS-like betacoronavirus (sarbecovirus) spike proteins that recognize SARS-CoV-2 variants of concern and zoonotic sarbecoviruses, we developed mosaic-8b RBD-nanoparticles presenting eight sarbecovirus RBDs arranged randomly on a 60-mer nanoparticle. Mosaic-8b immunizations protected animals from challenges from viruses whose RBDs were matched or mismatched to those on nanoparticles. Here, we describe neutralizing mAbs isolated from mosaic-8b-immunized rabbits, some on par with Pemgarda, the only currently FDA-approved therapeutic mAb. Deep mutational scanning, in vitro selection of spike resistance mutations, and single-particle cryo-electron microscopy structures of spike-antibody complexes demonstrated targeting of conserved RBD epitopes. Rabbit mAbs included critical D-gene segment RBD-recognizing features in common with human anti-RBD mAbs, despite rabbit genomes lacking an equivalent human D-gene segment, thus demonstrating that the immune systems of humans and other mammals can utilize different antibody gene segments to arrive at similar modes of antigen recognition. These results suggest that animal models can be used to elicit anti-RBD mAbs with similar properties to those raised in humans, which can then be humanized for therapeutic use, and that mosaic RBD-nanoparticle immunization coupled with multiplexed screening represents an efficient way to generate and select broadly cross-reactive therapeutic pan-sarbecovirus and pan-SARS-CoV-2 variant mAbs. Significance StatementSARS-CoV-2 variants and potential zoonotic sarbecovirus infections continue to threaten human health. Anti-SARS-CoV-2 mAbs that recognize conserved epitopes could be used prophylactically or therapeutically. We present approaches to elicit and identify cross-reactive mAbs using immunizations in animals with mosaic RBD-nanoparticles. We show that human and other mammalian immune systems can utilize different antibody gene segments to arrive at similar modes of antigen recognition, underscoring the flexibility of mammalian antibody repertoires and suggesting that experimental animals can be used to generate therapeutically-useful cross-reactive anti-RBD mAbs. The combination of mosaic-8b RBD-nanoparticles to focus the immune response and a multiplexed assay to select cross-reactive mAbs can be applied at larger scale, or against other pathogens, to identify mAbs of therapeutic and scientific potential.

immunology↗

bioRxiv2024

Metabolic reprogramming tips vaccinia virus infection outcomes by stabilizing interferon-g induced IRF1

Interferon (IFN) induced activities are critical, early determinants of immune responses and infection outcomes. A key facet of IFN responses is the upregulation of hundreds of mRNAs termed interferon-stimulated genes (ISGs) that activate intrinsic and cell-mediated defenses. While primary interferon signaling is well-delineated, other layers of regulation are less explored but implied by aberrant ISG expression signatures in many diseases in the absence of infection. Consistently, our examination of tonic ISG levels across uninfected human tissues and individuals revealed three ISG subclasses. As tissue identity and many comorbidities with increased virus susceptibility are characterized by differences in metabolism, we characterized ISG responses in cells grown in media known to favor either aerobic glycolysis (glucose) or oxidative phosphorylation (galactose supplementation). While these conditions over time had a varying impact on the expression of ISG RNAs, the differences were typically greater between treatments than between glucose/galactose. Interestingly, extended interferon-priming led to divergent expression of two ISG proteins: upregulation of IRF1 in IFN-{gamma}/glucose and increased IFITM3 in galactose by IFN- and IFN-{gamma}. In agreement with a hardwired response, glucose/galactose regulation of interferon-{gamma} induced IRF1 is conserved in unrelated mouse and cat cell types. In galactose conditions, proteasome inhibition restored interferon-{gamma} induced IRF1 levels to that of glucose/interferon-{gamma}. Glucose/interferon-{gamma} decreased replication of the model poxvirus vaccinia at low MOI and high MOIs. Vaccinia replication was restored by IRF1 KO. In contrast, but consistent with differential regulation of IRF1 protein by glucose/galactose, WT and IRF1 KO cells in galactose media supported similar levels of vaccinia replication regardless of IFN-{gamma} priming. Also associated with glucose/galactose is a seemingly second block at a very late stage in viral replication which results in reductions in herpes- and poxvirus titers but not viral protein expression. Collectively, these data illustrate a novel layer of regulation for the key ISG protein, IRF1, mediated by glucose/galactose and imply unappreciated subprograms embedded in the interferon response. In principle, such cellular circuitry could rapidly adapt immune responses by sensing changing metabolite levels consumed during viral replication and cell proliferation.

microbiology↗

bioRxiv2024

Prenatal Dexamethasone Programs Autonomic Dysregulation in Female Rats

Autonomic dysfunction is associated with cardiovascular and neurological disease, including hypertension, heart failure, anxiety, and stress-related disorders. Prior studies demonstrated that late gestation exposure to dexamethasone (DEX) resulted in female-biased increases in stress-responsive mean arterial pressure (MAP) and heart rate (HR), suggesting a role for glucocorticoid-mediated programming of autonomic dysfunction. The present study investigated the influence of sympathetic (SYM) or parasympathetic (PS) blockade on cardiovascular function in male and female rat offspring of mothers injected with DEX in utero (gestation days [GD]18-21). At 11-12-weeks of age, MAP, HR, and heart rate variability (HRV) were evaluated at baseline and in response to SYM antagonists (1-adrenoceptor + {beta}1-adrenoceptor), a PS (muscarinic) antagonist, or saline (SAL). To assess stress-responsive function, rats were exposed to acute restraint. Tyrosine hydroxylase was measured in adrenals and left ventricle, and gene expression for the {beta}1 adrenergic receptor was measured in left ventricle. Maternal DEX injection reduced basal HRV in male and female offspring. SYM blockade attenuated increases in stress-responsive HR and MAP. PS blockade elevated stress-responsive HR and MAP to a greater extent in Vehicle females. SYM and PS blockade produced equivalent effects on HR and MAP responses in male offspring, regardless of maternal treatment. Based on these findings, we suggest that maternal DEX injection disrupted autonomic regulation of cardiovascular function in females, resulting in a shift toward greater SYM input and less input from PS. Future studies will investigate whether changes in autonomic function are mediated by changes in central autonomic circuitry. New and NoteworthyThese studies use pharmacological antagonists to characterize the nature of the autonomic dysregulation induced in female offspring exposed to the synthetic glucocorticoid, dexamethasone, in utero. The female offspring of dams injected with dexamethasone in late gestation show a reduction in vulnerability to parasympathetic blockade and an increase in responses to acute restraint stress even in the presence of sympathetic blockade. This suggests that late gestation dexamethasone disrupts the normal development of the autonomic function in females leading to a shift in the sympathovagal balance.

physiology↗

bioRxiv2022

Perinatal High Fat Diet Exposure Alters Oxytocin and Corticotropin Releasing Factor Inputs onto Vagal Neurocircuits Controlling Gastric Motility

Perinatal high fat diet (pHFD) exposure alters the development of vagal neurocircuits that control gastrointestinal (GI) motility and reduce stress resiliency in offspring. Descending oxytocin (OXT; prototypical anti-stress peptide) and corticotropin releasing factor (CRF; prototypical stress peptide) inputs from the paraventricular nucleus (PVN) of the hypothalamus to the dorsal motor nucleus of the vagus (DMV) modulate the GI stress response. How these descending inputs, and their associated changes to GI motility and stress responses, are altered following pHFD exposure are, however, unknown. The present study used retrograde neuronal tracing experiments, in vivo recordings of gastric tone, motility, and gastric emptying rates, and in vitro electrophysiological recordings from brainstem slice preparations to investigate the hypothesis that pHFD alters descending PVN-DMV inputs and dysregulates vagal brain-gut responses to stress. Compared to controls, rats exposed to pHFD had slower gastric emptying rates and did not respond to acute stress with the expected delay in gastric emptying. Neuronal tracing experiments demonstrated that pHFD reduced the number of PVNOXT neurons that project to the DMV, but increased PVNCRF neurons. Both in vitro electrophysiology recordings of DMV neurons and in vivo recordings of gastric motility and tone demonstrated that, following pHFD, PVNCRF-DMV projections were tonically active, and that pharmacological antagonism of brainstem CRF1 receptors restored the appropriate gastric response to brainstem OXT application. These results suggest that pHFD exposure disrupts descending PVN-DMV inputs, leading to a dysregulated vagal brain-gut response to stress. Summary Figure O_FIG O_LINKSMALLFIG WIDTH=166 HEIGHT=200 SRC="FIGDIR/small/517564v3_ufig1.gif" ALT="Figure 1"> View larger version (34K): org.highwire.dtl.DTLVardef@7ad6acorg.highwire.dtl.DTLVardef@a3cd04org.highwire.dtl.DTLVardef@1e8dc9borg.highwire.dtl.DTLVardef@eb7c7c_HPS_FORMAT_FIGEXP M_FIG C_FIG KeypointsO_LIMaternal high fat diet exposure is associated with gastric dysregulation and stress sensitivity in offspring C_LIO_LIThe present study demonstrates that perinatal high fat diet exposure downregulates hypothalamic-vagal oxytocin (OXT) inputs but upregulates hypothalamic-vagal corticotropin releasing factor (CRF) inputs C_LIO_LIBoth in vitro and in vivo studies demonstrated that, following perinatal high fat diet, CRF receptors were tonically active at NTS-DMV synapses, and that pharmacological antagonism of these receptors restored appropriate gastric response to OXT C_LIO_LIThe current study suggests that perinatal high fat diet exposure disrupts descending PVN-DMV inputs, leading to a dysregulated vagal brain-gut response to stress. C_LI

neuroscience↗

bioRxiv2022

Canonical Wnt signaling regulates soft palate development through mediating ciliary homeostasis

Craniofacial morphogenesis requires complex interactions among tissues, signaling pathways, secreted factors, and organelles. The details of these interactions remain elusive. In this study, we analyzed the molecular mechanisms and homeostatic cellular activities governing soft palate development to improve regenerative strategies for cleft palate patients. We have identified canonical Wnt signaling as a key signaling pathway primarily active in cranial neural crest (CNC)-derived mesenchymal cells surrounding soft palatal myogenic cells. Using Osr2-Cre;{beta}-cateninfl/fl mice, we further discovered that Wnt signaling is indispensable for mesenchymal cell proliferation and subsequently myogenesis through mediating ciliogenesis. Specifically, we identified that Wnt signaling directly regulates expression of the ciliary gene Ttll3 through {beta}-catenin/Tcf7l2 complex. Impaired ciliary disassembly leads to differentiation defects of mesenchymal cells and indirectly disrupts myogenesis through decreased expression of Dlk1, a mesenchymal cell-derived pro-myogenesis factor. Moreover, we found that restoring ciliary homeostasis rescues mesenchymal cell proliferation in Osr2-Cre;{beta}-cateninfl/fl samples. This study highlights the role of Wnt signaling in palatogenesis through controlling ciliary homeostasis, which establishes a new mechanism for Wnt-regulated craniofacial morphogenesis.

developmental biology↗

bioRxiv2022

PKD1 and PKD2 mRNA cis-inhibition drives polycystic kidney disease progression

Autosomal dominant polycystic kidney disease (ADPKD), among the most common human genetic conditions and a frequent etiology of kidney failure, is primarily caused by heterozygous PKD1 mutations. Kidney cyst formation ensues when the PKD1 dosage falls below a critical threshold. However, no framework exists to harness the remaining allele or reverse PKD1 decline. Here, we show that mRNAs produced by the noninactivated PKD1 allele are cis-repressed via their 3-UTR miR-17 binding element. Eliminating this motif (Pkd1{Delta}17) improves mRNA stability, raises Polycystin-1 levels, and alleviates cyst growth in cellular, ex vivo, and mouse PKD models. Remarkably, Pkd2 is also autoinhibited via its 3-UTR miR-17 motif, and Pkd2{Delta}17-induced Polycystin-2 derepression partly compensates and retards cyst growth in Pkd1-mutant models. Moreover, acutely blocking Pkd1/2 cis-inhibition, including after cyst onset, attenuates murine PKD. Finally, PKD1{Delta}17 or PKD2{Delta}17 alleles revert cyst-pathogenic sequala in patient-derived primary ADPKD cultures. Thus, evading 3-UTR cis-interference and enhancing PKD1/2 mRNA translation is a potentially mutation-agnostic ADPKD-arresting approach.

genetics↗

bioRxiv2022

Genome-wide association reveals host-specific genomic traits in Escherichia coli

Escherichia coli is an opportunistic pathogen that can colonize or infect various host species. There is a significant gap in our understanding to what extent genetic lineages of E. coli are adapted or restricted to specific hosts. In addition, genomic determinants underlying such host specificity are unknown.By analyzing a randomly sampled collection of 1198 whole-genome sequenced E. coli isolates from four countries (Germany, UK, Spain, and Vietnam), obtained from five host species (human, pig, cattle, chicken, and wild boar) over 16 years, from both healthy and diseased hosts, we demonstrate that certain lineages of E. coli are frequently detected in specific hosts. We report a novel nan gene cluster, designated nan-9, putatively encoding acetylesterases and determinants of uptake and metabolism of sialic acid, to be associated with the human host as identified through genome wide association studies. In silico characterization predicts nan-9 to be involved in sialic acid (Sia) metabolism. In vitro growth experiments with a representative {Delta}nan E. coli mutant strain, using sialic acids 5-N-acetyl neuraminic acid (Neu5Ac) and N-glycolyl neuraminic acid (Neu5Gc) as the sole carbon source, indicate an impaired growth behaviour compared to the wild-type. In addition, we identified several additional E. coli genes that are potentially associated with adaptation to human, cattle and chicken hosts, but not for the pig host. Collectively, this study provides an extensive overview of genetic determinants which may mediate host specificity in E. coli. Our findings should inform risk analysis and epidemiological monitoring of (antimicrobial resistant) E. coli.

genomics↗