Biology subjects

Lee, J. Y.

Publications and source records attributed to Lee, J. Y..

At least 19 recordsLinked to original sources

bioRxiv2026

A positively selected microRNA controls a reversible aging program in striated muscle

Aging is the primary risk factor for most chronic diseases and is characterized in striated muscle by progressive functional decline, mitochondrial dysfunction, and chronic inflammation. The miR-128-1 locus resides within a positively selected haplotype on chromosome 2q21.3 associated with variation in grip strength, pulmonary function, and cardiometabolic traits in humans. Here, we show that antisense oligonucleotide-mediated inhibition of miR-128-3p restores muscle mass and function in aged mice, improves cardiac function while limiting adverse remodeling following myocardial infarction, and ameliorates skeletal and cardiac muscle pathology in mouse and pig models of Duchenne muscular dystrophy. Across these contexts, miR-128-3p inhibition induces a conserved transcriptional response characterized by activation of mitochondrial programs and suppression of inflammatory and fibrotic signaling, resembling the effects of established longevity interventions. These findings identify miR-128-3p as a regulator of a conserved aging-associated program and establish its inhibition as a strategy to restore tissue function across aging-related muscle pathologies.

molecular biology↗

bioRxiv2026

Combinatorial Modulation of Wnt, STAT3, TGF-β, and Tie2 Pathways Drives Brain Endothelial Cell-Like Differentiation from hiPSCs

During development, endothelial cells (ECs) migrate into the brain and acquire blood-brain barrier (BBB) properties such as tight junctions, limited transcellular transport, and high electrical resistance. Although key signaling pathways that are active in vivo have been identified, factors critical in inducing brain EC differentiation in vitro remain unclear. Here, we describe conditions that promote brain EC-like gene expression in human pluripotent stem cell (hiPSC)-derived ECs. Activation of Wnt/{beta}-catenin signaling upregulates the brain EC marker GLUT1 (SLC2A1) while suppressing the peripheral EC marker PLVAP. Simultaneously, stimulation of STAT3 by CNTF together with TGF-{beta} inhibition increases CLDN5 expression. We further found that hiPSC-derived ECs secrete high levels of angiopoietin-2 (ANGPT2) and that razuprotafib (AKB-9778), a PTPRB (VE-PTP) inhibitor, inhibits ANGPT2 and improves monolayer integrity. These results suggest that combinatorial modulation of specific signaling pathways stimulates the differentiation of human brain ECs in vitro.

developmental biology↗

bioRxiv2026

An overlooked microbial pathway links organic nitrogen turnover in composts to nitrous oxide formation

Biological N2O production from organic nitrogen is generally assumed to require canonical nitrification, which generates oxidized nitrogen that subsequently fuel denitrification. Whether this paradigm universally applies to nitrogen-rich microbial communities remains unclear. Here, we investigated N2O production across an industrial poultry manure composting process and found that substantial N2O formation occurred despite the apparent absence of canonical ammonia oxidation. Neither allylthiourea inhibition nor metagenomic analyses provided evidence for ammonia-oxidizing microorganisms or their activity. Instead, metagenomic analyses identified abundant bacterial nitric oxide synthase (bNos) genes, many of which were phylogenetically affiliated with Bacilli, the dominant bacterial group throughout composting. Physiological experiments with Bacillus isolates demonstrated a nitrification-independent route in which L-arginine was oxidized to NO2-/NO3-, consistent with bNOS-mediated NO formation followed by abiotic oxidation. Recovery of 15N-labelled N2O following 15NO2- addition established NO2- as an immediate precursor of aerobically produced N2O, confirming that the oxidized nitrogen generated through this alternative route subsequently fueled denitrification. Metagenomic analyses further revealed extensive denitrification potential but comparatively low nosZ abundance. Together, these findings identify a previously overlooked route linking organic nitrogen turnover to denitrification independently of canonical nitrification, thereby expanding current models of microbial N2O production in composts and potentially other protein-rich thermophilic environments.

microbiology↗

bioRxiv2026

Pyridoxine supplementation confers protection against SGPL1R222Q variant sphingosine phosphate lyase insufficiency syndrome

Sphingosine-1-phosphate lyase insufficiency syndrome (SPLIS) is a rare condition causing nephrotic syndrome, neuropathy, and other manifestations. SPLIS is caused by mutations in SGPL1, which encodes sphingosine-1-phosphate lyase (SPL), a pyridoxal 5-phosphate (PLP)-dependent enzyme needed to degrade the bioactive sphingolipid sphingosine-1-phosphate (S1P). Supplementation with the PLP precursor pyridoxine benefits some individuals with PLP-dependent enzymopathies. We sought to establish whether pyridoxine has therapeutic activity in SPLIS. Neurological improvement, plasma S1P normalization, and increased SPL activity in patient-derived fibroblasts were observed after pyridoxine supplementation in a patient with R222Q-variant SPLIS. Additionally, PLP dose-dependently augmented recombinant R222Q-variant SPL activity. To further explore pyridoxines effects, gene editing was employed to create an R222Q-variant SPLIS mouse model. SPLR222Q mice fed pyridoxine-enriched chow lacked obvious phenotypes. However, SPL inactivation, S1P accumulation, wasting, anemia, proteinuria, and glomerulosclerosis developed in SPLR222Q but not WT mice fed chow with reduced pyridoxine. Ultrastructural analysis and super-resolution microscopy showed podocyte loss and foot process effacement. Transcriptional profiling revealed a pattern of cytokine upregulation and extracellular matrix remodeling. Inhibiting S1P production prevented nephrosis in SPLR222Q mice fed chow lacking pyridoxine. Our findings establish a novel SPLIS mouse model that recapitulates R222Q-variant SPLIS, demonstrates its responsiveness to pyridoxine, and implicates S1P in its pathophysiology.

molecular biology↗

bioRxiv2026

PPM1B utilizes a trinuclear metal architecture for phosphatase activity

The metal-dependent protein phosphatase (PPM/PP2C) family regulates innate immune and cell death pathways through reversible phosphorylation. Although these enzymes contain a conserved third Mg2+/Mn2+ ion (M3) that is essential for activity, its chemical role in phosphate hydrolysis has remained unclear. Here, we report studies that reveal PPM1B promotes cell death during Pseudomonas aeruginosa infection and utilizes a trinuclear metal center in which M3 directly coordinates the substrate phosphate, positioning it for in-line SN2 hydrolysis. In addition to substrate orientation, M3 positions a water molecule to protonate the departing alkoxide, stabilizing the leaving-group. Functionally, M3 substitutes for the arginine clamp in phosphoprotein phosphatases (PPP), revealing that these evolutionarily distinct phosphatase families have converged on the same chemical strategy through fundamentally different catalytic architectures. Together, these findings define a three-metal mechanism in PPM phosphatases and identify the M3 site as a rare and potentially druggable feature for immune and infectious diseases.

biochemistry↗

bioRxiv2026

B7-H3 Modulates Cell Adhesion and Immune Evasion to Promote Tumor Progression and Natural Killer Cell Resistance in Hepatocellular Carcinoma

B7-H3 (CD276) is an immune checkpoint molecule frequently overexpressed in hepatocellular carcinoma (HCC) and represents a promising therapeutic target. However, its roles in tumor cell adhesion, metastatic behavior and immune evasion--particularly in interactions with natural killer (NK) cells--remain incompletely understood. In the present study, B7-H3 was depleted using small interfering RNA and CRISPR/Cas9 in epithelial (Huh7 and HepG2) and mesenchymal (SNU449) HCC cell lines. Tumor cell survival, apoptosis, adhesion, migration and invasion were evaluated using functional assays. Expression of adhesion molecules and immune checkpoint proteins was assessed by flow cytometry and western blotting. Oncogenic signaling pathways were analyzed by examining phosphorylation of Akt, ERK, FAK and STAT3. NK cell-mediated cytotoxicity was assessed using primary human NK cells. B7-H3 depletion reduced clonogenic survival and increased apoptosis in mesenchymal HCC cells under anchorage-independent conditions. Loss of B7-H3 impaired cell adhesion, migration and invasion, accompanied by downregulation of PTGFRN, E-cadherin, integrin 3 and integrin V, and reduced cell-to-cell aggregation under anchorage-independent conditions. B7-H3 depletion also decreased surface expression of PD-L1, PD-L2 and CD47. Notably, B7-H3-deficient cells exhibited enhanced susceptibility to primary NK cell-mediated cytotoxicity. Mechanistically, B7-H3 promoted tumorigenic signaling through Akt/S6, MVP/ERK and FAK/Src pathways in epithelial cells, and through FAK/Src and JAK2/STAT3 pathways in mesenchymal cells. Together, these findings reveal previously unrecognized roles for B7-H3 in coordinating adhesion and NK immune evasion in HCC, and support its therapeutic targeting for next-generation immunotherapies.

cancer biology↗

bioRxiv2026

Neuroanatomy of the clitoris

The clitoris is one of the least studied organs of the human body. The detailed anatomy of the clitoris is challenging to address through a gross dissection, as most of its parts are embedded internally, surrounded by pubic bone and several pelvic organs. While clinical imaging methods such as magnetic resonance imaging can capture the gross 3D morphology, they lack the spatial resolution required to resolve the detailed structures. In this study, we generated micron-scale computed tomography images of the female pelvises, leveraging a synchrotron radiation X-ray source. This unique data revealed the complex trajectory of the dorsal nerve of the clitoris, the main sensory nerve of the clitoris. Notably, the nerve trunks within the clitoral glans were revealed, with the maximum diameter ranging from 0.2 to 0.7 mm. They showed a tree-like branching pattern projecting towards the surface of the glans. We also revealed that some branches of the dorsal nerve of the clitoris ramify to innervate the clitoral hood and mons pubis. Finally, the posterior labial nerve, a branch of the perineal nerves, was shown to innervate the surroundings of the clitoris and the labial structures. These findings have an immediate impact on operations performed around the vulva area, such as gender-affirmation surgery and reconstruction surgery after genital mutilation.

neuroscience↗

bioRxiv2026

Stage-dependent biotic interactions may not be important for stochastic competitive dynamics with little variation in stage structure

O_LIStage-dependent interactions, in which different life cycle stages (e.g., juveniles, adults) exert different per-capita competitive effects, are widespread across ecological communities. However, whether explicitly accounting for such ontogenetic variation improves forecasts of stochastic community dynamics remains unclear. We tested how the strength of stage dependence and species life-history strategy influence the predictive accuracy of community models that either include or ignore stage-specific interactions. C_LIO_LIWe constructed stochastic two-species competition models using stage-structured matrix population models spanning five virtual life histories along the fast-slow continuum. Density dependence was imposed separately on juvenile survival, adult survival, progression, retrogression, or fertility, and the strength of stage dependence varied from adult-driven to juvenile-driven competition. We then fitted deterministic projection models with and without stage-dependent interaction terms to simulated time series and quantified predictive performance over 100 time-step forecasts using mean absolute percentage error (MAPE). C_LIO_LIIncreasing stage dependence consistently reduced the predictive accuracy of models that ignored stage structure. However, absolute prediction errors remained small across all scenarios (MAPE < 0.7%), even under strong stage dependence. The influence of life-history strategy depended on which vital rate was density dependent: when juvenile survival was density dependent, faster life histories showed larger errors; when progression, retrogression, or fertility were density dependent, slower life histories exhibited greater errors; and when adult survival was density dependent, no consistent life-history effect emerged. Across simulations, temporal variation in population structure was low (coefficient of variation < 0.036), and prediction error was strongly associated with the magnitude of structural fluctuations rather than life-history pace per se. C_LIO_LISynthesis. Stage-dependent interactions can, in principle, alter stochastic competitive dynamics, but their practical importance for ecological forecasting depends on the extent to which population stage structure fluctuates through time. When environmental stochasticity dominates and stage structure remains near equilibrium, simpler models that ignore stage dependence provide robust approximations of community dynamics. Our results identify conditions under which demographic detail is necessary for forecasting and highlight the central role of structural variability in linking life-history strategy to community-level dynamics. C_LI

ecology↗

bioRxiv2026

Addition of chemotherapy to radiotherapy promotes progenitor-exhausted CD8⁺ T-cell clonal dominance in head and neck cancer

Concomitant chemoradiotherapy (CRT) is a standard-of-care for unresectable locally-advanced head and neck squamous cell carcinoma (LA-SCCHN), but its immune effects, particularly compared to radiotherapy (RT) alone, remain unclear. Using syngeneic murine models, we integrated Nr4a3-Tocky reporter analysis with single-cell transcriptomics and T-cell receptor clonotyping comprehensively to profile intratumoural CD8 T-cells following RT/CRT. We show that CRT uniquely drives robust antigen-specific clonal expansion and biases differentiation toward progenitor (or precursor) exhausted (TPEX) phenotypes, while RT favours terminal exhaustion (TEX). Single-cell analyses reveal CRT-induced clonal dominance within TPEX subsets, suggesting the potential for enhanced immune reinvigoration. In peripheral blood mononuclear cells (PBMCs) from patients treated with CRT, high levels of TEX cells were found early and at 3 months post-treatment, with delayed peripheral TPEX expansion at 3 months, indicating phased progenitor recovery. These findings demonstrate distinct immunological remodelling by CRT versus RT and underscore the critical importance of treatment timing for optimising combination immunotherapy strategies in LA-SCCHN.

cancer biology↗

bioRxiv2026

In vivo deuteration reveals pronounced variation in myelin lipid turnover rates and reduced myelin renewal with ageing

Myelin turnover is essential for its structural and functional integrity, yet how this particularly lipid-rich membrane is renewed and why it deteriorates with ageing remain unresolved. Combining deuterium oxide administration in mice with high resolution lipidomics, we establish that brain lipid turnover rates are highly heterogeneous, differ by brain region, and depend primarily on lipid class. Half-lives of common glycerophospholipids in purified myelin were under 2 months whereas many sphingolipids exhibited half-lives exceeding 8 months, dependent on acyl chain length and saturation. Myelin sphingolipid and cholesterol replacement rates in the corpus callosum decreased markedly between 3 and 12 months of age, while disrupting lipid trafficking through ApoE ablation preferentially impaired cholesterol turnover and incorporation into myelin. Our results establish that myelin renewal occurs through continual replacement of individual lipid constituents in a manner that depends on lipid class, hydrophobicity, and ApoE-dependent trafficking, and that this process slows significantly with ageing.

biochemistry↗

bioRxiv2025

APE1 Coordinates Its Disordered Region and Metal Cofactors to Drive Genome Surveillance

Efficient recognition of DNA lesions such as apurinic/apyrimidinic (AP) sites is essential for maintaining genome stability. Apurinic/apyrimidinic endonuclease 1 (APE1) is the primary eukaryotic AP endonuclease, yet how it identifies rare lesions among vast stretches of undamaged DNA remains incompletely understood. Using single-molecule imaging combined with molecular dynamics simulations, we reveal that APE1 employs a distinctive dual mechanism to search DNA. First, Mg{superscript 2} coordination at the active site neutralizes clustered negative charges, stabilizing electrostatic contacts during scanning. Second, its N-terminal intrinsically disordered region (IDR)--a feature conserved only in eukaryotic homologs but absent in prokaryotic ExoIII--not only forms DNA through transient IDR contacts but also engages continuous interactions via the unprecedented 177 arginine residue within the structured nuclease domain, thereby prolonging residence time and enabling long-range diffusion. Together, these two modules synergize to promote a sliding-based search strategy tailored to the complexity of eukaryotic genomes. Consistent with this model, IDR deletion restricts APE1 to 3D collisions, whereas IDR duplication enhances 1D scanning. Thus, APE1 exemplifies how structural disorder and metal-ion coordination integrate to enable long-range lesion recognition, highlighting an evolutionary innovation in eukaryotic DNA repair.

molecular biology↗

bioRxiv2025

Urolithin A Restores Mitochondrial Function and Reverses Cardiac Remodeling in Heart Failure with Preserved Ejection Fraction

BackgroundHeart failure with preserved ejection fraction (HFpEF) accounts for nearly half of all heart failure cases; however, mechanism-based therapies targeting cellular dysfunction remain absent. Emerging evidence suggests that mitochondrial dysfunction and impaired quality control, particularly defective mitophagy, are central to the pathogenesis of HFpEF. Urolithin A (UA), a gut microbiome-derived postbiotic metabolite, has shown promise as a mitophagy activator in preclinical models; however, its therapeutic efficacy in HFpEF remains unknown. MethodsWe used a clinically relevant two-hit HFpEF mouse model (high-fat diet (HFD) plus N{omega}-nitro-L-arginine methyl ester (L-NAME)) and co-administered UA during disease progression. The cardiac structure and function were assessed using echocardiography, histology, and transmission electron microscopy. Mitochondrial bioenergetics were evaluated using Seahorse-based respirometry. Mitophagy flux was monitored using mt-Keima assays in H9c2 cells and human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs). Mechanistic insights were obtained using immunoblotting, integrated shotgun metagenomic and lipidomic profiling, and single-nucleus RNA sequencing (snRNA-seq). ResultsUA treatment significantly attenuated cardiac remodeling and fibrosis in HFpEF mice while improving diastolic function parameters. Transmission electron microscopy revealed restoration of the mitochondrial ultrastructure, and mitochondrial stress tests demonstrated enhanced oxidative phosphorylation capacity and glycolytic reserves. Immunoblot assays revealed that UA treatment recovered PINK1/Parkin-mediated mitophagy markers (reduced LC3-II and p62/SQSTM1). Mt-Keima assays confirmed enhanced mitophagic flux in H9c2 cells under HFpEF-like stress conditions. Integrated metagenomics and lipidomics revealed significant reductions in cardiovascular risk-associated ceramides. snRNA-seq demonstrated that HFpEF-like stress downregulated contractile, calcium-handling, and mitochondrial mitophagy gene programs. UA treatment restored the mitochondrial quality control signatures and normalized profibrotic and conduction-type cell populations. ConclusionsUrolithin A restored mitochondrial quality control through the activation of mitophagy and reversed cardiac remodeling in HFpEF. These findings establish UA as a mitochondria-targeted therapeutic candidate for HFpEF. Novelty and SignificanceO_ST_ABSWhat is known?C_ST_ABS{checkmark} Heart failure with preserved ejection fraction (HFpEF) is a heterogeneous syndrome driven by metabolic stress and myocardial remodeling, for which effective disease-modifying therapies are lacking. {checkmark}Mitochondrial dysfunction and impaired mitophagy have been implicated in HFpEF, but their roles in cardiomyocyte state remodeling and fibrosis remain incompletely defined. {checkmark}Urolithin A, a gut microbiome-derived metabolite, enhances mitophagy in aging and metabolic tissues, but its relevance to HFpEF has not been established. What new information does this article contribute?{checkmark} Urolithin A restores mitochondrial quality control and mitophagic flux in cardiomyocytes, improving diastolic function and attenuating cardiac remodeling in a two-hit HFpEF model. {checkmark}Integrated metagenomic and lipidomic analyses identify suppression of gut microbiome-associated ceramide biosynthesis as a systemic mechanism linked to Urolithin A-mediated cardioprotection. {checkmark}Single-nucleus RNA sequencing reveals that Urolithin A reverses maladaptive cardiomyocyte transcriptional state transitions toward fibrogenic and conduction-like programs.

molecular biology↗

bioRxiv2025

Fibroblast orchestration of inflammaging via NF-kB activation

Aged tissue is characterized by chronic inflammation known as "inflammaging". While this aging immune phenotype supposedly drives some of the most common diseases affecting the elderly, little is known about the structural drivers of inflammaging. In this study, we demonstrate that age-dependent activation of NF-kB in tissue fibroblasts remodels the immune architecture, promoting the emergence of an exhausted T cell population (GZMK+/CD8+) recently identified in normal aging, as well as autoimmunity and cancer. Fibroblast-specific NF-kB activation triggered a fibroblast-macrophage-T cell circuit to form tertiary lymphoid structures in the lung and promoted the emergence of exhausted GZMK+ T cells. Fibroblastic activation of NF-kB increased host susceptibility to acute lung injury and mimics severe pneumonia commonly seen in elderly patients, which was alleviated by deletion of GZMK+ T cells. Our data provide a structural basis for inflammaging, where fibroblasts orchestrate the complex immune aging phenotype in non-immune tissues, increasing susceptibility to age-related diseases. Highlights- Bronchus-associated lymphoid tissue (BALT) enriched for GZMK+ T cells develop with age - Lung adventitial fibroblasts demonstrate increased NF-kB activation with age. - Fibroblast activation of NF-kB in young animals recapitulates multiple features of normal lung immune aging - Depletion of GZMK+ cells decreases lung inflammation in a mouse model of acute respiratory distress syndrome (ARDS)

immunology↗

bioRxiv2025

Novel mouse model of cerebral microbleeds created by Crispr/Cas9-mediated Col4a1 deletion in adult brain microvessels

Cerebral small vessel disease is a leading cause of cognitive decline and stroke in the elderly, with cerebral microbleeds (CMBs) as one of the key imaging biomarkers. Our understanding of its pathophysiology remains limited due to the lack of appropriate animal models. We report a novel mouse CMB model created by disrupting collagen IV, a core component of the vascular basement membrane (BM), specifically within brain microvessels. Targeted deletion of Col4a1 was achieved in adult mice using brain endothelial-specific AAV vectors with CRISPR/Cas9. MRI revealed numerous CMBs with distributions similar to those of human CMBs. CMB burden increased progressively over six months following Col4a1 deletion in a dose-dependent manner, accompanied by cognitive decline and motor incoordination. Histological examination revealed hemosiderin deposits corresponding to MRI-detected CMBs without evidence of macroscopic hemorrhage or white matter lesions, while ultrastructural analysis demonstrated significant BM thinning in Col4a1-depleted microvessels. Analysis of human MRI and genomic data identified significant associations between CMB susceptibility and genetic variants in TIMP2, an endogenous inhibitor of the matrix-degrading enzyme MMP2, underscoring the clinical relevance of our model. These findings establish a direct causal relationship between microvessel COL4A1 and CMB, suggesting that dysregulated collagen IV homeostasis in BM underlies CMB development.

neuroscience↗

bioRxiv2025

Mechanical environment afforded by engineered polymer hydrogel critically regulates survival of neural stem cells transplanted in the injured spinal cord via Piezo1-mediated mechanotransduction

Neural stem cell (NSC) transplantation is a promising therapeutic approach for spinal cord repair, but poor graft survival remains a critical challenge. Here, we demonstrate that the mechanical properties of the transplantation microenvironment play a crucial role in NSC survival in the injured spinal cord. While our previously engineered imidazole-poly(organophosphazene) (I-5) hydrogel effectively prevented cavity formation by promoting extracellular matrix remodeling, NSCs transplanted with 10% hydrogel exhibited poor survival. Remarkably, increasing the hydrogel concentration to 16%, which created a 5-fold stiffer matrix, significantly enhanced NSC graft survival and synaptic integration. Using in vitro models with controlled substrate stiffness, we found that NSCs on stiffer substrates displayed enhanced adhesion, complex morphology, and increased viability. Importantly, we identified the mechanosensitive ion channel Piezo1 as the key molecular mediator of these stiffness-dependent behaviors. CRISPR/Cas9-mediated Piezo1 gene editing in NSCs significantly reduced graft survival in vivo when transplanted with 16% hydrogel, confirming that Piezo1-mediated mechanotransduction is essential for NSC survival in the injured spinal cord. Our findings reveal a previously unrecognized mechanism governing graft survival in the injured spinal cord and suggest that optimizing the mechanical properties of biomaterial scaffolds or targeting Piezo1-dependent mechanotransduction could substantially improve outcomes of cell-based therapies for neurological disorders.

neuroscience↗

bioRxiv2025

CDDO-Imidazole regulates RBC alloimmunization to the KEL antigen by activating Nrf2

During red blood cell (RBC) transfusion, production of alloantibodies can promote significant hemolytic events. However, most transfusion recipients do not form anti-RBC alloantibodies. Identifying mechanisms that inhibit alloimmunization may lead to prophylactic interventions. One potential regulatory mechanism is activation of the transcription factor, nuclear factor erythroid-derived 2-like 2 (Nrf2), a master regulatory of antioxidant pathways. Pharmacologic Nrf2 activators improve sequelae of sickle cell disease in pre-clinical models. The Nrf2 activator, 1-[2-cyano-3-,12-dioxooleana-1,9(11)-dien-28-oyl]imidazole (CDDO-Im), suppresses production of inflammatory cytokines including type 1 interferons (IFN/{beta}), which have been implicated in promoting RBC alloimmunization in transfusion models. Thus, we tested the hypothesis that the Nrf2 activator, CDDO-Im, regulates RBC alloimmunization. Here, we report that CDDO-Im induced Nrf2 activated gene expression and suppressed poly(I:C)-induced IFN/{beta}-stimulated gene (ISG) expression in human macrophages and murine blood leukocytes. In addition, following transfusion of wildtype mice with RBCs expressing the KEL antigen, CDDO-Im treatment inhibited poly(I:C)-induced anti-KEL IgG production and promoted post-transfusion recovery of KEL+ RBCs, but failed to do so in Nrf2-/- mice. Results indicate that activation of the Nrf2 antioxidant pathway regulates RBC alloimmunization to the KEL antigen in a pre-clinical model. If findings translate to other models and human studies, Nrf2 activators may represent a potential prophylactic intervention to inhibit alloimmunization. Key PointsO_LIThe antioxidant pathway, Nrf2, inhibits anti-RBC alloantibody responses in a pre-clinical transfusion model. C_LIO_LINrf2 activation may represent a prophylactic strategy to inhibit RBC alloimmunization in transfusion recipients. C_LI

immunology↗

bioRxiv2025

Synaptic Ultrastructural Alterations in Human Focal Cortical Dysplasia: Insights from Volume Electron Microscopy

Focal cortical dysplasia (FCD) is a developmental disorder of the cerebral cortex and a leading cause of drug-resistant epilepsy in children and young adults. A disrupted excitation-inhibition (E-I) balance is a hallmark of neuronal hyperexcitability in FCD, yet the underlying synaptic ultrastructural alterations remain poorly understood. Using volume electron microscopy, we performed a detailed morphological assessment of synaptic density, size, and organelle distribution within synapses in the temporal cortical layer III of an FCD patient. Our quantitation revealed a reduced density of inhibitory (symmetric) synapses on pyramidal neuron cell bodies. Notably, the dysplastic region displayed a lower density of excitatory (asymmetric) synapses but contained extra-large excitatory synapses, which contained an increased number of synaptic vesicles. Additionally, inhibitory synapses were located further away from the nearest excitatory synapses along distal dendrites, possibly weakening the effectiveness of shunting inhibition in the dysplastic area. There was also a decrease in presynaptic boutons housing mitochondria and in postsynaptic protrusions containing a spine apparatus, pointing to potential deficits in intracellular calcium handling and synaptic plasticity in the epileptogenic area. Moreover, maladaptive myelination was a prominent feature in the dysplastic region. These findings collectively indicate that synaptic architectural modifications may contribute to the neuronal hyperexcitability associated with epilepsy in FCD.

pathology↗

bioRxiv2025

Partial Input Loss Differentially Modifies Neural Pathways

Following input loss from degeneration, injury, and/or aging, downstream circuits undergo modifications that can impact neural computations. How neural computations across different pathways are affected by common input loss remain understudied. To leverage known cell types, well-defined circuitry, and molecular tools, we use the mouse retina to show how multiple pathways adjust their functional properties differently to common input loss and further locate these changes within each pathway. Specifically, we asked if two OFF ganglion cell types, alpha OFF-sustained (AOFF-S) and OFF-transient (AOFF-T) cells, and their respective dominant presynaptic partners, type 2 and type 3a cone bipolar cells, respond differentially to partial cone loss. We find that AOFF-T ganglion cells exhibit more circuit changes than AOFF-S ganglion cells, resulting in altered spatiotemporal tuning following partial cone loss. We show that the underlying mechanisms include changes in glutamatergic, GABAergic, and glycinergic circuits in the pathway of AOFF-T ganglion cells. In response to common input loss, our study finds different locations of circuit modifications across OFF pathways. These findings provide insight into how sensory pathways can compensate differentially to common input loss.

neuroscience↗