Biology subjects

Guo, F.

Publications and source records attributed to Guo, F..

At least 19 recordsLinked to original sources

bioRxiv2026

Distinct spatial organization of human hippocampal perfusion and microvascular pulsatility across age

Arterial pulsation can modulate neuronal activity through mechanosensitive pathways in mice, but whether vascular pulsatility is similarly related to neural organization in humans remains unclear. Here, using 7T MRI in 35 young and older adults, we mapped cerebral perfusion and microvascular volumetric pulsatility index (mvPI) across the unfolded hippocampus and integrated these measures with histological, electrophysiological, and transcriptomic reference maps. Perfusion and mvPI exhibited distinct spatial organization and age-related differences. In young adults, perfusion preferentially corresponded to parvalbumin-interneuron density and beta/gamma distribution, whereas mvPI was associated with theta-band distribution. A number of associations detected in young adults were not detected in the older adults maps. Spectral simulations showed qualitative similarity to heartbeat-related phase resetting as one possible explanation for the mvPI-theta relationship, while spatial transcriptomics revealed perivascular enrichment of PIEZO2, a candidate mediator of vascular mechanotransduction. Together, these findings establish perfusion and tissue-level pulsatility as distinct dimensions of human hippocampal vascular organization and provide a framework for investigating their relationships with neural dynamics across aging.

neuroscience↗

bioRxiv2026

Programmable design of functional RNAs through multimodal generative learning

RNA engineering is bottlenecked by the tight coupling among sequence, structure, and function, leaving the field reliant on heuristics or screening. We introduce RNAverse, a multimodal generative model that learns a conditionable design grammar from RNA sequences, experimental structural probing profiles, and functional annotations. Beyond setting a new state of the art across 16 predictive modeling tasks, RNAverse inverts into generative design across four distinct RNA classes through three regimes, requiring experimental testing of no more than 20 candidates per-task. Zero-shot in-painting generates snoRNAs that promote premature termination codon (PTC) readthrough, and chimeric aptazymes for ligand-controlled gene regulation, exceeding rational design or large-scale screens. In both settings, RNAverse outperforms family-adapted sequence-only baselines. Fine-tuned in-painting extends to an unseen functional class, yielding IGFBP3-binding aptamers with picomolar affinity that outperform SELEX winners. Iterative optimization engineers 5' UTRs that outperform clinical benchmarks, enhancing protein production in cell-based assays for both the Zolgensma gene therapy and the BNT162b2 COVID-19 vaccine, and boosting antibody responses to BNT162b2 in mice. Together, these results establish multimodal generative learning as a route from predictive RNA modeling to programmable specification of functional RNAs.

bioinformatics↗

bioRxiv2026

Structural engineering of dual-targeting antisense oligonucleotides enhances exon 44 skipping for treating Duchenne muscular dystrophy

Antisense oligonucleotides (ASOs) inducing exon-skipping during pre-mRNA splicing offer promising treatment for diseases such as Duchenne muscular dystrophy. Recently, dual-targeting ASOs that simultaneously bind two splicing regulatory sequences have been shown to improve exon-skipping efficiency. Current ASOs are designed to interact with target RNAs solely based on Watson-Crick base pairing. Here we report the development of dual-targeting three-dimensional bridge (3D-bridge) ASOs in which tertiary interactions are engineered to increase target-binding affinity and the number of target residues occupied. We designed a 3D-bridge ASO for skipping exon 44 of dystrophin mRNA and biochemically validated its enhanced binding affinity for the target RNA over a similar ASO with the tertiary interactions disrupted. We subsequently optimized the 3D-bridge ASO by varying its ends and ribose chemical modifications using patient-derived induced directly reprogrammed myotubes and identified an LNA/DNA mixmer as the most potent. We further demonstrate enhanced exon-skipping efficacy and potency of the 3D-bridge ASO compared to previously reported ASOs in myotubes differentiated from patient-derived primary myoblasts and MyoD-reprogrammed fibroblasts harboring mutations amenable to reframing through exon 44 skipping. In conclusion, the 3D-bridge ASO technology improves the current dual-targeting design, demonstrating the utility and power of structure-based ASO design methods.

pharmacology and toxicology↗

bioRxiv2026

Loss of polr1c disrupts myelination in a zebrafish model of POLR1C-associated disease

Pathogenic variants in POLR1C, which encodes a shared subunit of RNA Polymerases (Pols) I and III, cause Treacher Collins syndrome (TCS) and POLR3-related leukodystrophy. While Pol I and Tp53-dependent mechanisms have been implicated in the pathogenesis of TCS, the basis of hypomyelination in POLR1C-associated POLR3-related leukodystrophy remains incompletely understood. Here, we show that polr1c mutant zebrafish exhibit reduced myelination in addition to previously described craniofacial anomalies. Oligodendrocyte precursor cells exhibit increased activation of the Tp53 pathway; however, these cells do not undergo apoptosis. Consistent with this finding, tp53 inhibition reduces cell death in polr1c mutants but fails to restore myelination, indicating that myelination deficits are not driven by Tp53-dependent progenitor loss in this model. polr1c mutants also exhibit reduced rRNA transcription by Pol I and reduced expression of some Pol III-transcribed tRNAs. Altogether, these data indicate distinct tissue-specific responses to polr1c deficiency and suggest persistent impairment of rRNA transcription contributes to deficient myelin development. These findings expand the developmental consequences of polr1c loss and advance our understanding of the molecular basis of POLR1C-associated diseases.

developmental biology↗

bioRxiv2026

Engineering human myelin microphysiological systems for testing patient treatment response in multiple sclerosis

Multiple sclerosis (MS) is an autoimmune disease of the central nervous system characterized by neuroinflammation, demyelination, and neurodegeneration, associated with a complex interplay between the innate and adaptive immune systems. Currently, no cure is available for MS, and personalized disease-modifying treatment remains largely limited, partially due to the lack of preclinical human models that can faithfully recapitulate disease pathology and evaluate treatment responses at the individual-patient level. Here, we report a human myelin microphysiological system (myelin MPS) platform that recaptures disease phenotype and treatment response for testing patient treatment response. By culturing neural organoids on 3D-printed devices containing directional microfibers, followed by coculture with oligodendrocyte progenitor cells, 96 myelin MPS models can be generated within a conventional well plate. Using this myelin MPS platform, autologous T cells and monocytes from MS patients induced substantially greater demyelination than those from healthy donors, accompanied by expansion of proinflammatory T-cell subsets and increased myelin uptake by monocytes/macrophages after coculture with these healthy myelinating neural tissues. Integration of imaging and flow-cytometric features distinguished healthy-donor, untreated-MS, responder, and nonresponder profiles following treatment with prednisone, glatiramer acetate, interferon {beta}-1a, or dimethyl fumarate. Thus, the myelin MPS platform provides a scalable, human pathophysiology-relevant platform for functional phenotyping and individualized treatment-response evaluation in MS.

bioengineering↗

bioRxiv2026

Brain organoid computing for robotic decision-making

Biomimicry has inspired the evolution of robotics toward greater autonomy, adaptability, and symbiosis with humans and dynamic environments. However, current robotic systems still face major challenges in recapitulating the high-efficiency decision-making capabilities of the human brain under complex and dynamic conditions. Here, we present Brainobot, a biohybrid robotic system that establishes a brain organoid controller as a high-level robotic decision-making layer for closed-loop embodiment. By leveraging brain organoid reservoir computing, Brainobot interacts with dynamic environments by receiving and processing sensory inputs and generating motor actions. As a proof-of-concept demonstration, Brainobot is implemented in a humanoid robotic system to perform real-world tasks, including object grasping and laser chasing. Interestingly, Brainobot exhibits unique features, including cross-task adaptivity, high computing efficiency, and low energy consumption. Thus, our approach may provide insights for advancing robotic embodiment and understanding biological decision-making.

bioengineering↗

bioRxiv2026

Transdermal diagnosis and therapy using an integrated acoustofluidic patch

Transdermal biosensing and drug delivery provide convenient, pain-free, and user-friendly solutions for personalized therapy. However, challenges remain in detecting and treating acute diseases, primarily due to current limitations in effective detection of transdermal biomarkers and administration of therapeutics to an individual within a short time window in a real-world environment. Here, we integrate a compact acoustofluidic patch for transdermal sampling, sensing, and delivery in a rapid and automated manner. By leveraging acoustic streaming and 3D-printed microfluidic designs, acoustofluidic sampler and injector modules are assembled for penetration of the skin stratum corneum, precise sampling of skin interstitial fluids, and controlled percutaneous release of therapeutics, respectively. By incorporating an electrochemical sensing module, the integrated patch can be further developed to achieve in situ and rapid detection of transdermal biomarkers and automated transdermal delivery of therapeutics via closed-loop control. As a proof-of-concept application, we demonstrate our approach can detect and reverse life-threatening acute allergic reactions in a mouse model of anaphylaxis by rapid sampling and sensing transdermal histamine followed by automated transdermal delivery of epinephrine. The innovative acoustofluidic patch may enable a new kind of transdermal devices for personalized therapy of various acute diseases.

bioengineering↗

bioRxiv2026

Information processing-like phenotype of human brain organoids

Human brain organoids recapitulate key physiological features and functions of the human brain and hold remarkable potential for studying neurological diseases. Despite clinical evidence suggesting that neurodegenerative diseases impair the information-processing ability of the human brain, the capacity of brain organoids for information processing and its relationship to neural network function remain largely unexplored. Here, we test and quantify information-processing-like properties of human cortical organoids using a task-based functional phenotyping framework (Brainopheno). We demonstrate the pattern-processing-like phenotype of cortical organoids through the representation and classification of evoked neural activities in response to distinct spatial input stimulation patterns via a microelectrode array (MEA) system. Moreover, this functional phenotype emerges with network maturation and is disrupted by pharmacological perturbations, linking classification performance to the functional integrity of organoid neural networks (ONNs). Importantly, this functional phenotype also reveals functional deficits in ONNs altered by a familial Alzheimer's disease (AD)-associated gene mutation (APP) and by monocytes from patients with sporadic AD. This work may establish a new quantifiable functional phenotype of neural organoids and provide a framework to bridge molecular and cellular profiles with neural circuit function for basic neurology, disease phenotyping, and therapeutic development.

bioengineering↗

bioRxiv2026

Promoter architecture and developmental-expression divergence in the Daphnia pulex complex

Changes in gene regulation are central to developmental evolution, yet how transcription-initiation architecture contributes to developmental expression divergence remains poorly understood. Here, we integrated chromosome-level genome assemblies, developmental RNA-seq, and STRIPE-seq-based transcription start site (TSS) profiling to examine regulatory divergence between two lineages of the Daphnia pulex complex, KAP4 and CON21, across embryonic, juvenile, and adult stages. The two lineages shared a broadly conserved developmental transcriptional program, but KAP4 consistently expressed more protein-coding genes and long non-coding RNAs than CON21. Genes with stage-specific expression were weakly expressed and showed elevated nucleotide diversity and sequence divergence relative to persistently expressed genes, consistent with relaxed purifying selection. Comparative transcriptomic analyses revealed strong stage-dependent expression divergence between the two lineages: the greatest similarity occurred during late embryonic to early juvenile development rather than mid-embryogenesis, providing limited support for a canonical developmental hourglass pattern. STRIPE-seq uncovered a conserved two-peak TSS organization upstream of annotated translation-start sites, but the relative use of distal and proximal initiation regions differed between lineages. Motif analyses further indicated that these initiation regions are associated with distinct cis-regulatory sequence environments. Promoter shape was closely linked to transcriptional output, with broad promoters showing the highest expression, peaked promoters the lowest, and intermediate promoters occupying an intermediate state. Together, these findings suggest that developmental regulatory divergence in the D. pulex complex is shaped by fine-scale remodeling of TSS usage and promoter architecture.

evolutionary biology↗

bioRxiv2026

Ablation and Seed-driven Restoration of an Alpha-Satellite Devoid Human Centromere Reveals Size Homeostasis Mechanisms

Human centromeres are epigenetically defined chromatin domains marked by nucleosomes containing the histone H3 variant CENP-A, which recruit the constitutive centromere-associated network (CCAN) to assemble functional kinetochores. Maintaining centromere function, including chromatin domain size and the ability to assemble the kinetochore, is essential for proper mitotic division across eukaryotes. In humans however, mechanistic studies of centromere establishment, maintenance, and size regulation have been hindered by the highly repetitive nature of canonical alphoid centromeres. Here, we develop a genetically tractable human neocentromere system which is devoid of repetitive DNA sequences. Using targeted genetic manipulation of a monoallelic naturally occurring neocentromere, we show that partial loss of centromeric chromatin triggers restoration of the residual CENP-A domain through seed-driven, sequence-independent expansion into adjacent naive chromatin. In contrast, creation of new domain boundaries without loss of centromeric chromatin mass results only in local boundary remodeling, without substantial domain expansion. These findings indicate that centromere formation proceeds through two mechanistically distinct steps, beginning with acquisition of a CENP-A seed and followed by regulated domain expansion to generate a mature centromere. More broadly, our results support a model in which centromeres transition between a maintenance state that preserves domain size and a restoration state that rebuilds centromeric chromatin following perturbation. Together, this study establishes a genetically tractable platform for dissecting the mechanisms governing human centromere formation, chromatin domain dynamics, and size homeostasis.

cell biology↗

bioRxiv2026

HiBASIL: Hierarchical Bayesian Source Inference and Localization for Spatial Epidemiology

O_LIIdentifying spatial origins of biological invasions, disease outbreaks, or environmental contaminants is critical for timely intervention. However, existing methods struggle to resolve overlapping signals from multiple sources or account for extreme zero/one inflation in bounded data. C_LIO_LIWe developed HiBASIL (Hierarchical BAyesian Source Inference and Localization), a Bayesian framework that jointly infers source coordinates and mechanistic dispersal kernels from zero-one-inflated spatial observations. We systematically tested HiBASIL across 2,500 simulations spanning localized to long-distance dispersal regimes, various foci weight mixtures (0.5/0.5 to 0.95/0.05), and varying sample sizes (N = 50 to 500) to evaluate geometric sensitivity, spatial robustness, parameter recovery capability, and multi-focal resolution. We applied HiBASIL in tracking cucurbit downy mildew dispersal in field experiments including non-inoculated control, single-focus, and two-foci treatments arranged in a randomized complete block design. To demonstrate broad applicability, we validated HiBASIL with historical London cholera epidemic data to determine whether it could accurately localize the epicenter. C_LIO_LIHiBASIL achieved 100% accuracy in kernel identification under correct model specification, 100% and 98% (2% predictive equivalence) in under- and over-parameterization scenarios, and maintained appropriate parsimony in null scenarios. Source localization was highly precise, with a median bias of 0.11 m, successfully resolving minority sources contributing only 5% of the observations. Importantly, the framework provides intrinsic self-diagnostics, signaling model complexity mismatch through posterior bimodality (under-parameterization) or parameter collapse (over-parameterization). HiBASIL is applicable in various epidemic scenarios, including diffused long-distance dispersal. Under an isotropic process, HiBASIL achieved sub-meter mean errors on two-source localization in cucurbit downy mildew field tests, effectively isolating transmission signals from landscape noise despite sparse sampling. Despite confounding influence of underlying network processes in the historical cholera data, the posterior localized the epicenter to within [~] 33m, demonstrating portability beyond plant disease epidemiology. C_LIO_LIIn summary, HiBASIL can accurately localize multiple sources across various epidemic scenarios, extremely unbalanced foci mixtures, and sparse sampling conditions. HiBASIL also demonstrates wide applicability across agricultural and human disease epidemic systems. By providing an open-source Python implementation, HiBASIL enables rigorous inverse spatial inference for ecology, epidemiology, and environmental monitoring, transforming how discrete transmission sources are identified in complex landscapes. C_LI

ecology↗

bioRxiv2026

Cellular origin and therapeutic potential of SERPINA3N in ischemic stroke

Murine serine protease inhibitor clade A member 3N (SERPINA3N) and its human homolog SERPINA3 are injury-associated molecules induced in virtually all neurological conditions including ischemic stroke. Clinically, SERPINA3 is elevated in stroke patients, correlating with severe brain pathology and worse neurological outcomes. Yet, the exact cellular sources and therapeutic value of SERPINA3N/SERPINA3 in the ischemic brain remain elusive. Here, we report that oligodendrocytes are the major sources of SERPINA3/SERPINA3N and that SERPINA3N exerts neurotoxic effects in experimental cerebral ischemia. Given SERPINA3Ns secretory nature, we used knock-in Serpina3n-tdTom reporter mice to define its temporospatial evolution. The tdTom signal was barely detectable by day1 but gradually increased from day 3 through day 7 following cerebral ischemia. The majority of tdTom+ cells were identified as oligodendrocytes and astrocytes with fewer found in neurons or microglia. This cellular identity was corroborated by meta-analysis of single-cell transcriptomics datasets and human ischemic stroke brain data. Antagonizing SERPINA3N attenuated blood-brain barrier disruption, neuroinflammation, and neuronal damage and improved neurological function in a mouse model of cerebral ischemia. These findings resolve a longstanding debate regarding the cellular origins of SERPINA3N, identifying oligodendrocytes as its major source. Our studies highlight SERPINA3N antagonism as a possible therapeutic intervention for ischemic stroke, providing new insights for precision therapies that target oligodendroglia- or astroglia-specific SERPINA3N.

neuroscience↗

bioRxiv2026

A Synthetic Microbial Therapy Rewires Antitumor Immunity Across Multiple Cancer Types

Microbial immunotherapies show promise against cancer, yet broad efficacy and mechanistic insight remain elusive. Here, we introduce SPIKE 1.0 (S1.0), a metabolically engineered bacterium that converts tryptophan into immunomodulatory hydroxyindoles via tryptophan monooxygenase to remodel the tumor microenvironment (TME). A single systemic dose of S1.0 elicited potent, durable antitumor responses across multiple murine models, including humanized mice, with minimal toxicity. S1.0 enhanced inflammatory signaling, activated innate and adaptive immunity, and promoted T cell persistence, memory, and resistance to exhaustion. It outperformed checkpoint inhibitors and synergized with chemotherapy. Multi-omics profiling revealed that S1.0 rewired amino acid metabolism in tumor-infiltrating immune cells and disrupted immunosuppressive networks. These results establish S1.0 as a scalable, cost-effective microbial immunotherapy with broad translational potential for solid tumors.

immunology↗

bioRxiv2026

Bidirectional communication between neurons in the mesentery and ileal myenteric neurons

The intestinal mesentery has been recently classified as a new organ and contains various cell types including adipocytes, preadipocytes, endothelial cells, and immune cells. In addition, neuronal cell bodies are found in the small intestinal mesentery and are situated either individually or clustered together with glial cells in small ganglion structures close to the gut wall. However, little is known about the origin or function of these extra-intestinal mesenteric neurons. The aim of this study was to better these characterize mesenteric neurons and to examine their connectivity with the ENS using calcium imaging in adult mouse ileum with the mesentery attached. Here we show that neurons in the mesentery express typical ENS neurochemical markers, respond to 5-HT, ATP and the nicotinic agonist DMPP, and receive nicotinic synaptic inputs. Furthermore, using labeling with the neuronal tracer DiI, some mesenteric neurons were found to project into the gut wall and can provide functional excitatory inputs to myenteric neurons. By contrast, we did not find evidence for mesenteric neurons providing inputs to other extrinsic neuronal targets, suggesting that they preferentially interact with the ENS. We also demonstrate that mesenteric neurons can be activated by intestinal distension and that the mesentery provides a source of inhibition to the myenteric plexus. Taken together, we show that the ENS not only interacts with vagal and spinal afferents, and sympathetic and parasympathetic nerves, but also neurons situated in the mesentery. Finally, our data suggest that these neurons may provide a form of negative feedback to the myenteric plexus such as in the event of intestinal distension. These findings have important implications for the regulation of intestinal motility in physiological and pathophysiological conditions.

neuroscience↗

bioRxiv2026

Selective vulnerability of excitatory cortical neurons to ZMYND11 loss reveals cell-type-specific mechanisms of neurodevelopmental disorder risk

Excitation/inhibition (E:I) imbalance is a convergent mechanism in neurodevelopmental disorders (NDDs), yet whether NDD risk genes disrupt excitatory and inhibitory neurons through shared or distinct molecular programs remains poorly understood. Using human pluripotent stem cell-derived cortical projection and medial ganglionic eminence-like inhibitory neurons, we show that loss-of-function mutations in the chromatin reader ZMYND11 produce cell-type-selective vulnerability in cortical excitatory neurons. ZMYND11-deficient excitatory neurons exhibit hyperexcitability accompanied by de-repression of BMP signaling, dysregulation of glutamate receptor expression, and a shift toward non-brain splicing isoforms, whereas these molecular signatures are largely absent in ZMYND11-deficient inhibitory neurons. This cell-type selectivity is associated with differential upregulation of RBFOX family splicing regulators. Structure-function analysis reveals that MYND domain is required for normal progenitor dynamics and neuronal excitability. Together, these findings indicate that E:I imbalance in ZMYND11-associated NDD arises primarily from cell-type-selective vulnerability of excitatory cortical projection neurons and identify MYND domain as a critical determinant of neuronal function. HighlightsO_LIZMYND11-deficient excitatory neurons (ExNs) show hyperexcitability. C_LIO_LIAltered BMP signaling & glutamate receptor levels are implicated in mutant ExNs. C_LIO_LIInhibitory neurons show attenuated response to ZMYND11 loss. C_LIO_LIThe MYND domain in ZMYND11 is a critical regulator of neuronal excitability. C_LI

neuroscience↗

bioRxiv2026

Cell-type-resolved RNP topologies reveal dynamic structural mechanisms of splicing and therapeutic targets

Resolving RNA conformations in native ribonucleoprotein (RNP) complexes remains a fundamental challenge. Here, we introduce spatial hydroxyl acylation reversible crosslinking with immunoprecipitation (SHARCLIP) to simultaneously capture RNA-RNA, RNA-protein and protein-protein contacts in cells. SHARCLIP profiling of HNRNPC-associated RNA conformations established a global phased map of ribonucleosomes, resolving a decades-old debate on heterogenous nuclear (hn)RNP assembly. We built a dynamic structural atlas across seven cell lineages for >10,000 RNAs, generating ~200 million contacts, and identifying millions of dynamic loops, steric blockers and conformational switches that control splicing outcome. Deciphering the structural logic of mutually exclusive exons (MXEs) enabled rational design of structure-breaking and stabilizing antisense oligonucleotides (ASOs). We demonstrate effective isoform swapping in 12 genes linked to genetic disorders. SHARCLIP provides a comprehensive roadmap for cellular RNA structural biology and structure-guided RNA therapeutics.

molecular biology↗

bioRxiv2026

Sphk1-S1P signaling drives blood-brain barrier breakdown after intracerebral hemorrhage via HIF-1α-dependent upregulation of Bsg-MMP-9

Blood-brain barrier (BBB) breakdown is a critical pathological event driving secondary brain injury and poor outcomes following intracerebral hemorrhage (ICH). However, the mechanisms governing acute BBB breakdown after ICH remain incompletely understood. Here we demonstrate that the Sphk1-S1P-S1PR3 signaling plays a pivotal role in this process. Sphk1 expression was significantly upregulated in the perihematomal endothelial cells of both ICH patients and mice, with levels positively correlating with BBB dysfunction severity and poor clinical outcomes. Using endothelial-specific genetic gain- and loss-of-function approaches, we found that Sphk1 knockdown attenuated BBB leakage, reduced hematoma volume and brain edema, preserved tight junction integrity, and improved neurological function at 1-day post-ICH, whereas Sphk1 overexpression exacerbated these pathological features. Mechanistically, transcriptomic profiling of perihematomal endothelial cells revealed that prior to its established role in Nlrp3-mediated pyroptosis, Sphk1 promotes early BBB breakdown by regulating the Bsg-MMP-9 axis. Endothelial-specific Bsg deletion completely abrogated the deleterious effects of Sphk1, confirming Bsg as an indispensable intermediary through which Sphk1 signals to MMP-9. ATAC-seq and dual-luciferase assays further demonstrated that Sphk1-generated S1P signals through S1PR3 to activate HIF-1, which directly binds the Bsg promoter to drive its transcription, ultimately promoting MMP-9-mediated tight junction degradation. These findings delineate a complete hierarchical signaling cascade from metabolic enzyme to transcriptional regulation and subsequent barrier injury, establishing the Sphk1-Bsg-MMP-9 axis as a promising therapeutic target for ICH. One sentence summaryThis work identifies an early and pivotal mechanism of blood-brain barrier breakdown after intracerebral hemorrhage, demonstrating that Sphk1-generated S1P signals through S1PR3 to activate HIF-1, which directly transactivates Bsg expression, leading to MMP-9-mediated tight junction degradation, thereby establishing a novel hierarchical axis with therapeutic potential.

cell biology↗

bioRxiv2026

Hippocampal Glucuronyl C5-epimerase promotes stress resilience by directly engaging PI3K through a non-enzymatic mechanism

Major depressive disorder (MDD) seriously affects human physical and mental health and causes global socioeconomic burdens. Stress-induced depressive etiology is linked to dendritic atrophy in the hippocampus, however, the underlying mechanism was poorly understood. Here, we identify that glucuronyl C5-epimerase (Glce), a heparan sulfae-modifying enzyme, as a critical regulator of hippocampal dendritic integrity and stress resilience. Genetic ablation of Glce in the hippocampal excitatory neurons is sufficient to induce dendritic atrophy and depressive-like behaviors, whereas its restoration rescues these deficits. Notably, Glce levels are reduced in the plasma of depressed individuals. We further find that Glce functions independently of its enzymatic activity, instead binding directly to and activating PI3K (p85/p110), thereby triggering an Akt/CREB/BDNF signaling cascade. Together, our findings uncover a non-canonical role for Glce and establish that Glce-PI3K-BDNF axis is essential for maintaining hippocampal structure and behavioral resilience, thereby highlighting a critical role of Glce in the pathophysiology of depression.

neuroscience↗