Biology subjects

Sato, M.

Publications and source records attributed to Sato, M..

At least 19 recordsLinked to original sources

bioRxiv2026

Enhancing the hyaline cartilage regenerative potential of induced pluripotent stem cell-derived chondrocyte cell sheets

Introduction Autologous and allogeneic chondrocyte cell sheet transplantation has shown safety and potential efficacy for cartilage defects associated with knee osteoarthritis. Although polydactyly-derived chondrocyte (PDC) cell sheets have been used clinically for allogeneic transplantation, a scalable and reliable alternative cell source is needed. This study aimed to establish a proof-of-concept protocol for generating chondrocyte cell sheets from clinical-grade human induced pluripotent stem cells (iPS cells). Methods Cartilaginous tissue was generated from human iPS cells, and isolated chondrocytes were used to fabricate iPS cell-derived chondrocyte sheets. In Phase 1, sheets were produced in high-serum medium under normoxic, hypoxic, or hypoxic/high-seeding-density conditions and compared with PDC sheets using a three-dimensional in vitro model and xenogeneic orthotopic transplantation in an immunodeficient rat model. In Phase 2, sheets were produced in low-serum medium under hypoxic/high-seeding-density conditions and evaluated for cartilage-related gene expression, secreted factors, cell surface marker expression, and in vivo cartilage repair. Results In Phase 1, hypoxic/high-seeding-density culture enhanced in vitro chondrogenic properties. However, after transplantation, iPS cell-derived chondrocyte sheets formed fibrotic repair tissue, whereas PDC sheets generated hyaline-like cartilage. In Phase 2, low-serum culture increased expression of cartilage-related genes, including collagen type II alpha 1 (COL2A1) and SRY-box transcription factor 9 (SOX9), enhanced secretion of transforming growth factor beta 1 and melanoma inhibitory activity, and upregulated CD9, CD26, CD56, CD201, CD227, and GD2. Low-serum iPS cell-derived chondrocyte sheets regenerated hyaline cartilage at 4 weeks, and the repair tissue was maintained at 12 weeks without bone formation. Conclusions A robust fabrication protocol enabled human iPS cell-derived chondrocyte sheets to regenerate hyaline-like cartilage in vivo. These findings support their potential as a scalable cell source for clinical cartilage repair.

bioengineering↗

bioRxiv2026

Crystal structure of a class II UDP-glucose-hexose-1-phosphate uridylyltransferase from Bifidobacterium longum involved in human milk oligosaccharide metabolism

Infant-associated bifidobacteria utilize lacto-N-biose I (LNB) and galacto-N-biose (GNB), major components of human milk oligosaccharides and intestinal mucin, respectively, through the GNB/LNB metabolic pathway. A UDP-glucose-hexose-1-phosphate uridylyltransferase (GalT) from Bifidobacterium longum JCM 1217 (BlGalT2) catalyzes a key step in this pathway. BlGalT2 belongs to class II GalTs within the histidine triad (HIT) superfamily, a rare protein group distinct from canonical class I GalTs. Here, we determined the crystal structure of BlGalT2 at 2.25 [A] resolution, providing the first three-dimensional structure of a class II GalTs. BlGalT2 is a monomeric enzyme with an architecture distinct from canonical class I GalT, comprising characteristic HIT1 and HIT2 catalytic core subdomains and an extended auxiliary domain that forms a self-contained active site. Kinetic analysis revealed a strong preference for GalNAc-1P over Gal-1P, with a 50-fold lower Km for GalNAc-1P, consistent with a hydrophobic pocket accommodating the N-acetyl group. Metal analysis and activity measurements indicated that Zn2+ is required for full activity, and structural prediction suggested its coordination by residues including the first histidine of the HIT motif. AlphaFold3 prediction and mutational analysis identified residues involved in nucleotide-sugar recognition and supported a Ping-Pong reaction mechanism involving a covalent enzyme-uridine monophosphate intermediate. These findings reveal how class II GalTs have evolved a unique structural framework and substrate specificity for N-acetylated sugars. Moreover, the structure of BlGalT2 fills the final missing gap in bifidobacterial HMO metabolism and provides molecular insight into the adaptation of bifidobacteria to host-derived glycans.

biochemistry↗

bioRxiv2026

LBD-type transcription factors suppress local and systemic nitrogen responses through distinct regulatory pathways

Nitrogen (N) is a major determinant of plant growth and productivity. Because soil N availability and internal N demand fluctuate, plants have evolved sophisticated mechanisms to coordinate N acquisition and utilization at the whole-plant level. However, how this coordination is achieved remains poorly understood. Here, we show that N-inducible LATERAL ORGAN BOUNDARIES DOMAIN transcription factors LBD37, LBD38, and LBD39 (LBDs) function as repressors of local N uptake and assimilation and systemic N-demand signaling in Arabidopsis. Triple mutants lacking these three LBDs displayed enhanced nitrate influx and increased accumulation of nitrate, amino acids, and total N. Transcriptome analysis identified an array of N-starvation- and nitrate-inducible genes derepressed in shoots and roots, including C-TERMINALLY ENCODED PEPTIDE (CEP) and CEP DOWNSTREAM (CEPD) genes, as well as genes involved in N uptake and assimilation. Grafting and genetic analyses revealed that LBDs gate the systemic N-demand signaling relay by repressing CEP and CEPD expression organ-autonomously. We also found that LBDs locally repress genes involved in N uptake and assimilation through a distinct regulatory mechanism. We propose that LBDs are key transcriptional repressors in a regulatory framework for optimizing N acquisition and utilization under fluctuating N conditions at the whole-plant level.

plant biology↗

bioRxiv2026

Independent evolution of flavour and parthenocarpy in fig, one of the earliest domesticated fruit trees

Domestication often modifies multiple traits in concert, but whether fruit quality and reproductive mode share a genetic basis in perennial crops has not been tested at multi-omics resolution. In fig (Ficus carica), one of the earliest domesticated fruit trees and a crop with archaeobotanical evidence of cultivation over 11,000 years ago, domestication yielded both distinctive flavour and parthenocarpy, fruit development without pollination. We integrated whole-genome resequencing, transcriptomics, volatile and metabolite profiling, and taste sensor data across a diverse accession panel, using Bayesian GWAS/TWAS and multi-omics factor analysis. Flavour emerges as an integrated sensory system led by aroma, which modulates taste through cross-modal interactions, with sugar-acid balance as a secondary axis; these quality traits map to numerous independent loci. Parthenocarpy instead traces to a single perfectly concordant chromosome 04 haplotype (Eden) centred on FcMYB101-like, carrying a selective-sweep signature and a derived allele fixed in cultivated figs but rare across the genus. Flavour and reproductive mode thus evolved along separate genomic trajectories, allowing each to be improved independently.

plant biology↗

bioRxiv2026

EC1 body controls sperm cell reception via gamete pit formation.

The remarkable efficiency of double fertilization in flowering plants depends on the precise delivery of immotile sperm cells to two female gametes1. Although sperm cells are rapidly released from the pollen tube, how they are accurately directed to their fertilization site has remained unknown. Here we identify a transient extracellular structure, termed the gamete pit, that forms at the egg cell-central cell (EC-CC) interface immediately after pollen tube discharge and serves as the landing site for sperm cells. Gamete pit formation is enabled by localized dissociation of the EC-CC interface, mediated by extracellular protein assemblies designated EC1 bodies. These structures contain extracellular deposits enriched in EGG CELL 1 (EC1) peptides2, including amyloid-like assemblies. Loss of EC1 bodies prevented gamete pit formation, causing sperm-cell backflow or catastrophic over-penetration of pollen tube contents into the central cell. Surprisingly, ectopic deposition of a heterologous amyloidogenic protein alleviated over-penetration and partially restored fertility. Our findings reveal a mechanism by which extracellular protein assemblies remodel the gamete interface for sperm-cell reception, uncover an unexpected structural role for the conserved gamete-activating peptide EC1, and establish protein-mediated cell-interface remodeling as a fundamental principle underlying double fertilization in flowering plants.

plant biology↗

bioRxiv2026

CaMKII-LUZP1 signaling couples cytoskeletal acetylation and autophagy to drive neuronal plasticity

Cytoskeletal acetylation and autophagy are fundamental drivers of neuronal plasticity, yet how these pathways are coordinated across subcellular compartments remains unknown. Here, we identify LUZP1 as a signaling organizer that couples cytoskeletal acetylation to autophagy in hippocampal neurons. LUZP1 deficiency impaired neurite outgrowth and dendritic spine maturation while promoting ciliary elongation; these phenotypes were partially mirrored in neuron-specific Luzp1 knockout mice, which also showed altered locomotor behavior. Mechanistically, LUZP1 promoted neurite extension by enhancing ATAT1-dependent -tubulin acetylation while driving spine maturation and limiting ciliary growth by restraining HDAC6-dependent cortactin (CTTN) deacetylation. An acetylation-mimetic CTTN mutant rescued both spine and ciliary defects caused by LUZP1 deficiency. In parallel, blocking autophagy-dependent OFD1 degradation attenuated ciliary elongation, linking CTTN deacetylation to increased autophagy under LUZP1-deficient conditions. Finally, activated CaMKII associated with LUZP1 and selectively enhanced its interaction with HDAC6 and CTTN, coupling neuronal activity to cytoskeletal remodeling. Together, these findings identify a CaMKII-LUZP1 pathway that integrates cytoskeletal acetylation with autophagy to coordinate neuronal morphogenesis and ciliary homeostasis. HighlightsO_LILUZP1 couples cytoskeletal acetylation to autophagy in hippocampal neurons C_LIO_LILUZP1 promotes neurite extension through ATAT1-dependent -tubulin acetylation C_LIO_LILUZP1 restrains HDAC6-CTTN signaling to drive spine maturation and limit ciliary growth C_LIO_LICaMKII selectively strengthens the LUZP1-HDAC6-CTTN pathway C_LI

neuroscience↗

bioRxiv2026

PCP-dependent polarity propagation across neuronal columns in the Drosophila medulla

Planar cell polarity (PCP) signaling establishes coordinated tissue polarity through asymmetric localization of core PCP factors and propagation of polarity information between neighboring cells. While PCP mechanisms are well characterized in continuous epithelial tissues, whether PCP-dependent polarity propagation can operate across discontinuous neuronal structures remains unclear. During pupal development of the Drosophila medulla, R8 photoreceptor axon terminals transiently form horseshoe-shaped structures whose orientation reflects neuronal column polarity. Here, we show that Frizzled (Fz) progressively becomes asymmetrically localized within developing horseshoe structures, whereas Van Gogh (Vang) transiently accumulates in adjacent glial cells during early developmental stages. Conditional disruption of Vang in glial cells impaired asymmetric Fz localization and disrupted horseshoe orientation polarity. Glial Vang localization preceded the emergence of robust Fz asymmetry, suggesting that glial Vang functions during an early polarity establishment phase. Furthermore, mosaic knockdown of fz in R8 neurons altered Fz localization in neighboring R8 terminals, suggesting local propagation of polarity information between adjacent neuronal columns. Together, our results suggest that PCP-dependent polarity propagation operates across discontinuous neuronal columns in the developing medulla and provide a framework for understanding coordinated polarity formation in neural tissues lacking continuous epithelial organization.

developmental biology↗

bioRxiv2026

TAB1 and ASP1 act antagonistically on cytokinin signaling to regulate axillary meristem formation in rice

Plants continuously develop shoot branches derived from axillary meristems. In rice (Oryza sativa), TILLERS ABSENT1 (TAB1), an ortholog of Arabidopsis WUSCHEL, plays an essential role in axillary meristem formation by promoting stem cell proliferation. Although several genes associated with TAB1 function have been identified, the molecular mechanisms underlying stem cell proliferation during axillary meristem formation remain poorly understood. Here we identify ABERRANT SPIKELET AND PANICLE1 (ASP1), a TOPLESS-like transcriptional corepressor, as a novel regulator of axillary meristem formation, and investigate downstream mechanisms regulated by TAB1 and ASP1. In asp1, the stem cell region was expanded, indicating that ASP1 negatively regulates stem cell proliferation. Notably, WOX4, a paralog of TAB1, was precociously expressed in asp1, possibly in association with expansion of the stem cell region. Genetic analysis further revealed that asp1 mutation rescued the loss of axillary meristems in tab1. Transcriptome analysis showed that several type-A RESPONSE REGULATOR (OsRR) genes, encoding negative regulators of cytokinin signaling, were upregulated in tab1 relative to wild type, asp1, and the tab1 asp1 double mutant. Consistently, fluorescence of the synthetic cytokinin reporter was absent during axillary meristem formation in tab1 but was detected in wild type and tab1 asp1. Moreover, overexpression of OsRR10 inhibited axillary meristem formation, phenocopying tab1. Collectively, these findings suggest that TAB1 activates cytokinin signaling by repressing type-A OsRR expression, whereas ASP1 negatively regulates cytokinin signaling by promoting the expression of these genes. Thus, rescue of the tab1 phenotype by asp1 mutation probably reflects restoration of cytokinin signaling.

plant biology↗

bioRxiv2026

A Novel Slow-Progressive Knee Osteoarthritis Murine Model Induced by Non-Invasive Posterior Cruciate Ligament Rupture in Mice

ObjectiveRecently, alternatives to animal testing, such as new approach methodologies, are being developed in the orthopedic research field; animal models still provide valuable insights into the pathogenesis of knee osteoarthritis (OA). However, commonly used models develop OA much more rapidly and severely than those observed in human patients. We aimed to develop a novel murine model that closely mimics the slow progression of human OA with posterior Cruciate ligament (PCL) rupture. Design12-week-old C57BL/6 mice were induced to PCL-rupture (PCL-R) by manually applying an external tibial posterior translation force. We analyzed joint kinematics, histological observations, and bone structure to confirm the absence of concurrent injury on day 0. Then, joint stability and the pathophysiological progression of knee OA were analyzed at 8, 16, and 34 weeks post-PCL-R. The destabilized medial meniscus (DMM) model was also analyzed to compare the OA progression. ResultsNon-invasive PCL-R intervention induced the complete rupture in the central region of PCL without concurrent injury. The PCL-R group showed larger posterior tibial deviation than the INTACT (P=0.008). Regarding the range of motion in the PCL-R group, there was no limitation in range of motion on day 0, but extension limitations occurred at weeks 16 and 34 weeks. Histologically, articular cartilage degeneration in PCL-R was milder than DMM. In the subchondral bone, micro-CT reconstruction images indicated that, compared with the INTACT group, the DMM group observed progressive subchondral bone formation from 16 weeks post-surgery. In contrast, the PCLR group maintained the subchondral bone structure even at 34 weeks. ConclusionsPCL-R model induced mild abnormal mechanical stress depending on posterior instability, and cartilage degeneration occurred more slowly in this model than in DMM models.

pathology↗

bioRxiv2026

Therapeutic knockdown of MLKL reduces diet-induced obesity and improves insulin signalling in mature adipocytes

Obesity affects one in three adults and is complicated by adipose inflammation, lipotoxicity and cell death. We previously identified RIPK1 as a genetic determinant of human obesity risk and adipose inflammation. Because RIPK1 is the apical kinase in the necroptosis pathway upstream of RIPK3 and the executioner protein MLKL, and emerging evidence links MLKL to lipid metabolism, MLKL has surfaced as a potential metabolic regulator. However, conflicting findings in Mlkl knockout mice fed a high fat diet have left its therapeutic relevance unresolved. MLKL has not been previously targeted through therapeutic knockdown in vivo in the context of diet-induced obesity. Here, we evaluated two independent MLKL antisense oligonucleotides (ASOs) in high fat diet (HFD)-fed C57BL/6J mice. In a 24-week progression model, MLKL ASO markedly reduced body weight, fat mass and hepatic steatosis compared with controls, while preserving lean mass. MLKL knockdown also lowered the respiratory exchange ratio, indicating a shift toward increased fat oxidation. In the intervention model, once obesity was established after 12 weeks of HFD feeding, both MLKL ASOs, and similarly, two independent RIPK1 ASOs, reversed weight gain and improved systemic glucose control. In vitro, MLKL-CRISPR/Cas9 knockout blocked 3T3-L1 adipogenesis, indicating a requirement for MLKL during adipocyte differentiation. However, in mature adipocytes, MLKL siRNA reduced palmitic acid-induced lipid accumulation, increased isoprenaline-stimulated lipolysis, and prevented TNF-mediated suppression of insulin-mediated AKT signalling and glucose uptake. Collectively, these findings demonstrate that partial MLKL suppression reprograms whole-body energy metabolism, enhances insulin sensitivity and limits diet-induced adiposity. MLKL, therefore, represents a promising and mechanistically novel therapeutic target for obesity and insulin resistance.

physiology↗

bioRxiv2026

Profiling cell proliferation after whole-genome duplication in human cells

Though whole-genome duplication (WGD) contributes to cancer progression, the mechanism of post-WGD cell proliferation remains unclear. Here, using 6-day live-imaging, we analyzed the proliferation dynamics of more than 150 post-WGD HCT116 cell lineages. A quantitative comparison of mitotic patterns and cell fates between proliferative and non-proliferative lineages revealed that multipolar chromosome segregation in early mitosis is a key factor limiting the proliferative capacity of post-WGD progenies. Multipolar chromosome segregation suppressed post-WGD cell viability, particularly when accompanied by drastic chromosome loss or when it repeatedly occurred. Tracing proliferative lineages elucidated that they proliferated mainly by imposing the risk of multipolar chromosome segregation on one of two sub-lineages that formed after the first bipolar division. Meanwhile, a considerable proportion of proliferative lineages consisted entirely of progeny of early multipolar chromosome segregation events. Our results highlight key cellular events that determine the proliferation dynamics and diversity of post-WGD progenies, providing a fundamental reference for understanding WGD-associated bioprocesses. Summary statementLive image tracing of >150 cell lineages reveals the cross-generation dynamics of multipolar chromosome segregation that determine the fates of post-whole-genome duplication progeny cells.

cell biology↗

bioRxiv2026

Chromid-like secondary replicons as key sites of biosynthetic gene clusters in Ktedonobacteria

Soils harbour immense biosynthetic gene cluster (BGC) diversity that can mediate microbial interactions, yet this potential is still mapped unevenly across the tree of life. Ktedonobacteria--a class of actinomycete-like bacteria within phylum Chloroflexota--are widespread in terrestrial environments and repeatedly dominate pioneer communities in extremely oligotrophic volcanic bare-ground soils; however, their secondary metabolism and genome architecture remain poorly characterised. Here, we integrate targeted cultivation using volcanic soils from Mount Zao with genome-resolved metagenomics and public genomes to analyse 183 ktedonobacterial genomes. Using antiSMASH and BiG-SLiCE, we identified 1,546 BGCs comprising 1,162 non-redundant gene-cluster families (GCFs). In our dataset, nearly one quarter of genomes encode [≥]10 distinct GCFs, and several family-level clades show mean GCF counts comparable to those in genus Streptomyces. Most ktedonobacterial BGCs are highly divergent from reference collections and exhibit unusually low intra-genomic redundancy, suggesting broad, underexplored chemotypes. Long-read assemblies from ten strains reveal recurrent 1.6-3.5 Mb chromid-like secondary replicons with chromosome-like composition but distinct maintenance signatures. These replicons are consistently enriched in BGCs and mobility-associated genes, with mobility loci concentrated near BGC boundaries. Collectively, our results expand the current knowledge of the phylogenetic landscape of soil biosynthetic diversity and highlight chromid-like secondary replicons as major genomic reservoirs for specialised metabolism in Ktedonobacteria.

microbiology↗

bioRxiv2025

Potential cost and combinatorial effects of commensal gut microbes on survival of individual honey bees

The western honey bee, Apis mellifera, is attracting attention as an experimental model to investigate general interactions between hosts and gut microbiota because of their noteworthy simple and stable bacterial community. Here, we systematically explore the effect of five core bacteria, Snodgrassella alvi, Bifidobacterium asteroides, Bombilactobacillus Firm-4, Lactobacillus Firm-5, and Gilliamella apicola, on the longevity of individual honey bees. Generating gnotobiotic bees harboring all 32 different combinations of the core bacteria, we found that bacterial colonization generally reduces the host lifespan. This indicates that despite commensal gut microbes coevolved with the host, their presence is in principle costly for survival of individual bees. Regression analysis including higher-order interactions reveals that bacterial interactions have significant impacts on the host lifespan and show a qualitative trend: 2- and 4-way interactions exhibit positive, while 3- and 5-way interactions are negative. Numerical simulations based on a general Lotka-Volterra model demonstrate that the observed trend is reproduced when competitive interactions dominate in the bacterial community. This study combining empirical and theoretical approaches suggests the general costs of harboring gut microbiota and the stabilization of the bacterial community by higher-order interactions, which will advance our understanding of how commensal gut microbes and their interactions specifically influence host physiology. ImportanceGut microbes are recognized for their profound effects on the host physiology. They provide numerous benefits to their hosts, whereas gut dysbiosis leads to various disease or mental impairment. Although understanding of such association with hosts is of pivotal importance, many animals have complex gut microbiome comprised of hundreds of bacterial species, most of which cannot be cultured in the laboratory. This is a big challenge to disentangle intimate interactions of commensal microbes with their hosts. Here, we exploit characteristics of honey bee gut microbiota, which consists of only five core bacteria, to generate gnotobiotic bees harboring defined bacterial communities with all 32 (i.e., 25) possible combinations. This large-scale analysis uncovers not only individual impacts of the core species but also combinatorial effects generated by their interaction on the host lifespan. Finally, using simple mathematical models, we explain that the combinatorial effects are largely derived from competitions between gut microbes.

ecology↗

bioRxiv2025

Systemic immune dysregulation in hypertensive disorders of pregnancy persists years after delivery

BackgroundHypertensive disorders of pregnancy (HDP), including preeclampsia and gestational hypertension, are associated with an increased risk of cardiovascular disease (CVD) later in life. Mechanisms that link HDP to CVD, however, remain unclear. MethodsWe used a high-dimensional single-cell mass cytometry approach to profile the distribution and functional responses of maternal immune cells in three separate groups of HDP cases and normotensive controls, sampled antepartum, postpartum, and several years postpartum (midlife). We used multivariable sparse modeling to distinguish HDP cases from controls. ResultsWe accurately distinguished HDP cases from controls at all three study timepoints, with area under the receiver operator characteristic (AUROC) curve values of 0.814 for the antepartum group, 0.757 for the postpartum group, and 0.692 for the midlife group. Distinct immune signatures for each model underscore the dynamic dysregulation of the immune system throughout life. In addition, we identified a persistent immune dysregulation signal among HDP cases at all three timepoints, characterized by increased B cell frequency and decreased pSTAT3 response upon cytokine stimulation in classical monocytes. ConclusionsPersistent immune dysregulation among women with a history of an HDP may contribute to elevated long-term risk of CVD development.

immunology↗

bioRxiv2025

High-Resolution Imaging of the Rhizosphere Using Resin-Embedded Cross-Sectional Polishing and Scanning Electron Microscopy for Biological Samples (bioCP-SEM)

Understanding microbial colonization in plant-associated environments requires high-resolution imaging of intact plant-microbe interfaces under natural soil conditions. However, conventional electron microscopy is limited by sample distortion and poor compatibility with heterogeneous substrates. Here, we present bioCP-SEM, a cross-sectional polishing scanning electron microscopy technique optimized for biological specimens inhabiting unsterilized soil. This method integrates resin embedding, diamond band saw sectioning, and mechanical polishing to enable high-quality imaging across large, complex samples. Using bioCP-SEM, we visualized bacterial clusters in a model plant root, and multilayered biofilm-like structures and fungal structures, including arbuscule-like forms, in a wild weed species. We further applied this method to intact moss collected from an urban environment, capturing spatially resolved interactions among biofilms, spores, protozoa, and annelids. Notably, microbial cells and subcellular structures, such as cilia, were preserved in situ. These results demonstrate the versatility of bioCP-SEM for mapping microbial architecture across diverse biological and environmental contexts.

microbiology↗

bioRxiv2025

Microglia-dependent LPS preconditioning prevents neuroinflammation-induced behavioral deficits in male mice

Neuroinflammation contributes to psychiatric disorders, but preventive strategies targeting brain immune cells remain unexplored. Here we demonstrate that low-dose lipopolysaccharide (LPS) preconditioning prevents systemic inflammation-induced behavioral abnormalities through microglia-dependent mechanisms in male mice. Mice received preconditioning with 0.2 mg/kg LPS or saline for two consecutive days, followed by high-dose LPS challenge (5 mg/kg) or saline seven days later. Behavioral assessment revealed that preconditioning specifically prevented social preference deficits induced by systemic inflammation (preference score: -0.49{+/-}0.19 vs 0.14{+/-}0.10, p<0.01), while showing limited effects on locomotor activity and depression-like behaviors. Additionally, LPS preconditioning prevented anxiety-like behavior in a chronic corticosterone model and attenuated hippocampal inflammatory gene expression. Immunohistochemical analysis demonstrated that preconditioning suppressed microglial activation in hippocampal CA1 region, particularly reducing PBR/IBA1 ratio (37.5{+/-}2.4% vs 27.6{+/-}2.8%, p<0.01), with less pronounced effects in CA3. Critically, pharmacological microglial depletion using PLX3397 during the preconditioning period completely abolished these protective effects, establishing the causal role of microglia. Flow cytometric analysis revealed preconditioning-induced shifts in brain macrophage subpopulations defined by TMEM119 and CD45 expression patterns. Transcriptomic profiling identified subpopulation-specific responses, with one subset showing LPS-response pathway enrichment despite minimal gene expression changes, while another displayed extensive but functionally non-specific transcriptional alterations. These findings establish microglial preconditioning as a novel preventive strategy for neuroinflammation-induced social behavioral deficits and suggest potential therapeutic applications for psychiatric disorders involving neuroinflammatory components.

neuroscience↗

bioRxiv2025

Single-cell-level digital twins for preterm birth prevention strategies

Digital twin models can accelerate therapeutic development by enabling low-risk testing of candidate interventions. In preterm labor (PTL), a major pregnancy complication where clinical trials face unique ethical and financial barriers, digital twins are especially valuable for evaluating new therapies targeting immune dysfunctions driving PTL. Yet, current models lack single-cell resolution, limiting detection of cell-type-specific mechanisms, off-target effects, and the design of personalized interventions. We present Simulated Immunome Modeling of Clinical Outcomes (SIMCO), a single-cell-level digital twin framework that models immunomodulatory treatment effects on the timing of labor using immunome-wide, single-cell simulations. SIMCOs digital twins are trained and validated on a newly generated mass cytometry atlas of the pregnant immunome exposed to nine candidate drugs preselected for PTL prevention. Applying SIMCO to an independent cohort of pregnant individuals, we simulate treatment effects on gestational length, screening for candidate drugs that delay labor timing and providing system-level mechanistic insight for each drug candidate. Tetrahydrofolate, maprotiline, and the combination of aspirin and lansoprazole emerged as top candidates for PTL prevention, delaying labor onset primarily through enhanced mTOR signaling in innate immune cells and attenuated JAK/STAT signaling in naive CD4 T cells. The codebase is available at https://github.com/ofondeur/SIMCO/.

immunology↗

bioRxiv2025

Camsap3-Mediated Microtubules Maintain Transzonal Projections Essential for Germline-Soma Communication during Ovarian Follicle Maturation in Mice

Oocytes are surrounded and nursed by layers of maternal somatic granulosa cells (GCs) in ovarian follicles. Within a follicle, GCs extend actin-containing transzonal projections (TZPs) to an oocyte across the zona pellucida to establish communication. In contrast, microtubules have rarely been observed in some TZPs, and their significance in TZP organisation and functions for follicular maturation remain largely unknown. Here, using super-resolution microscopy, we visualised the presence of microtubules alongside F-actin in most TZPs. Knockout (KO) mice of the microtubule minus-end binding protein Camsap3 (calmodulin-regulated spectrin-associated protein 3) exhibited infertility with fewer developing late-stage follicles. In earlier stages of Camsap3-KO follicles, the number of TZPs was reduced compared to that in wild-type follicles, and microtubules in TZPs were disorganised, which led to a decrease in physical contact between GCs and oocytes. We also found that TZP morphology in wild-type follicles transforms over time during follicle development, and Camsap3 modulates TZP morphology by assisting the organisation of microtubules as well as F-actin. Our findings thus suggest that Camsap3-mediated microtubules play a crucial role in governing the number and morphology of TZPs to ensure successful follicle development for the production of fertile oocytes.

cell biology↗