Biology subjects

Hayashi, T.

Publications and source records attributed to Hayashi, T..

At least 19 recordsLinked to original sources

bioRxiv2026

Continuous Large Maf Activity Maintains Fast Myofiber Identity and Multicellular Homeostasis in Adult Skeletal Muscle

Fast myofibers are preferentially affected during aging, exhibiting atrophy and shifts toward slower myofiber programs, yet the mechanisms preserving established fast-fiber identity remain unclear. Here, we show that the large Maf transcription factors Mafa, Mafb, and Maf are continuously required to maintain type IIb myofiber identity in adult skeletal muscle. Inducible deletion of large Mafs caused near-complete loss of type IIb fibers, a transition toward type IIx/IIa states, reduced strength, and increased fatigue resistance. RNA-seq and ATAC-seq revealed transcriptional and chromatin accessibility remodeling across the fast myosin locus, characterized by persistent loss of Myh4 expression and increased accessibility around Myh1. Single-nucleus RNA-seq identified transient myonuclei co-expressing multiple myosin isoforms before emergence of a Myh1-dominant state, accompanied by remodeling of non-myonuclear cell populations. These changes shared features with aging- and denervation-associated muscle remodeling. Thus, continuous large Maf activity maintains adult fast myofiber identity and coordinates skeletal muscle tissue homeostasis.

cell biology↗

bioRxiv2026

Striatal dopamine dynamics across temporal scales in brain-specific Atp2a2 heterozygous knockout mice during reward conditioning

Dysregulated dopamine signaling is implicated in schizophrenia and mood disorders, yet how disease-associated genes alter dopamine dynamics during behavior remains poorly understood. ATP2A2 encodes sarco/endoplasmic reticulum Ca2+-ATPase 2 (SERCA2), a regulator of intracellular Ca2+ homeostasis, and has been associated with psychiatric vulnerability. Brain-specific Atp2a2 heterozygous conditional knockout (het-cKO) mice exhibit behavioral abnormalities and elevated extracellular dopamine in the nucleus accumbens (NAc) with microdialysis, but it lacks the temporal resolution to resolve rapid, context-dependent dopamine dynamics. Here, we used dual-site fiber photometry with the genetically encoded dopamine sensor dLight1.2 to monitor dopamine signals simultaneously in the NAc and tail of the striatum (TS) during classical reward conditioning. Control and het-cKO mice acquired task-related licking comparably. Nevertheless, het-cKO mice showed enhanced NAc reward-evoked dopamine responses in the pooled analysis, with indications of more frequent and longer-lasting spontaneous transients. Responses to unexpected reward omission were larger in het-cKO mice in both regions during the early phase, but they were not detected after further training. Notably, late-phase suppression of reward-predictive NAc dopamine responses by a preceding aversive outcome persisted in het-cKO mice, although evidence for genotype dependence was inconclusive. Regional dopamine transporter (DAT) protein expression showed no clear genotype differences. These findings identify context-dependent alterations in dopamine signaling across multiple temporal scales and striatal regions in brain-specific Atp2a2 haploinsufficiency, highlighting intracellular Ca2+ regulation and dopamine release as priorities for direct investigation. These results may help clarify the biological links between ATP2A2 haploinsufficiency and neuropsychiatric dysfunction.

neuroscience↗

bioRxiv2026

Heart rate deceleration reflects expectation violation during reaching

Heart rate (HR) deceleration occurs following movement error and has been interpreted as an autonomic response to adverse behavioral outcomes. However, movement errors not only represent adverse movement outcomes but may also violate expectations. The present study employed a reaching movement paradigm using a robotic manipulandum in male and female human participants to dissociate the contributions of movement outcome and expectation violation to HR responses. We confirmed that HR deceleration occurred following visuomotor perturbations that induce movement errors, consistent with previous studies. However, when contextual cues predicted upcoming movement outcomes, HR deceleration emerged during movement preparation rather than following movement error, suggesting the involvement of expectation in HR responses. Moreover, across varying levels of expectation for different movement outcomes, HR deceleration was associated with unexpected movement outcomes rather than with the negative valence of movement outcomes. By altering target width to permit successful movements despite visuomotor rotations, we further found that HR deceleration was more strongly associated with task error than with sensory prediction error. Together, these findings indicate that HR responses during movement are more closely associated with violations of movement expectation than with movement error itself. These findings provide a new perspective on autonomic responses during sensorimotor processing and suggest that HR may serve as a physiological marker of expectation-related processing during movement.

neuroscience↗

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

Genomic, spatial, and evolutionary insights into a dominant Mycoplasmatota symbiont colonizing the body wall of deep-sea holothurians

Subcuticular bacteria (SCB) are widespread symbionts of echinoderms and often dominate the body-wall microbiome, suggesting important roles in host physiology. However, their diversity, metabolic properties, and host associations remain poorly characterized. Here, we report a novel dominant SCB lineage associated with deep-sea holothurians, Scotoplanes spp. collected from the Northwest Pacific. We recovered two high-quality genomes, including a 649-kb complete circular genome, and propose a new genus and species, "Candidatus Abyssoplasma scotoplanesicola", within Mycoplasmatota. The two genomes showed a highly reduced metabolic repertoire, lacking central pathways including glycolysis. In contrast, acidic cell-surface-associated proteins, including large proteins exceeding 5,000 amino acids, accounted for 27.6% of the complete genome and clustered near defense islands. Localized genome plasticity in these regions, revealed by comparison between the two closely related genomes, suggests a possible mechanism for diversification of cell-surface proteins at the host-symbiont interface. "Candidatus Abyssoplasma scotoplanesicola" occupied 76.4-98.9% of the body-wall microbiome of the Scotoplanes specimens. Fluorescence in situ hybridization analysis confirmed that these bacteria formed aggregates on the epidermal side of the body wall. Overall, this study provides genome-and spatially resolved views of dominant SCB in holothurians and offers evolutionary insights into host-interface diversification in the deep-sea holothurian body wall.

microbiology↗

bioRxiv2026

Iterative co-creation of harmonized human and non-human primate cellular and structural ontologies and 3D common coordinate frameworks for the basal ganglia

A major goal of the BRAIN Initiative Cell Atlas Network (BICAN) is to create a suite of foundational reference cell atlases and associated standards for human and non-human primate brains. Central to this goal is the creation of cross-species harmonized cellular taxonomies and structural parcellations with formal ontologies that can be mapped into 3D reference frameworks bridging neuroimaging and cellular and histological resolutions. We describe here an iterative approach, focused initially on the basal ganglia, to co-create structural and cellular ontologies in human, macaque and marmoset brains, including a Harmonized Ontology of Mammalian Brain Anatomy (HOMBA), and to map and refine structural parcellations into neuroimaging-based common coordinate frameworks. These references provide the framework for documenting and mapping all experimental sampling in BICAN, allowing analyses of cellular and molecular variation as a function of topographic position, and enabling comparisons of cellular, molecular and neuroimaging-based functional variation within and between primate species. HighlightsO_LIA hierarchical Harmonized Ontology of Mammalian Brain Anatomy (HOMBA) covering 2348 structures C_LIO_LIHOMBA-annotated 3D common coordinate frameworks (CCFs) of the basal ganglia across species C_LIO_LIHistologically informed 3D parcellation/atlas of 280 human subcortical structures indexed by HOMBA C_LIO_LIMapping and integration of structural, cellular and functional data with HOMBA and CCFs C_LI

neuroscience↗

bioRxiv2026

Topical Activatable Fluorescence Probes for Rapid Intraoperative Detection of Peritoneal Dissemination in High-Grade Serous Ovarian Carcinoma

BackgroundEpithelial ovarian cancer (EOC) is one of the most lethal gynecologic malignancies, largely because most patients are diagnosed at an advanced stage with peritoneal dissemination. High-grade serous carcinoma (HGSC), the most common and aggressive EOC subtype, requires complete cytoreductive surgery to improve the prognosis; however, minute disseminated lesions are often missed by conventional intraoperative inspection. Here, we aimed to develop fluorescence probes for rapid and sensitive intraoperative detection of HGSC peritoneal dissemination. MethodsWe screened a hydroxymethyl rhodamine green (HMRG)-based fluorescence probe library consisting of 381 protease- and aminopeptidase-reactive fluorescence probes using tumor and non-tumor specimens from patients with HGSC. The target enzyme of the hit probes was identified by means of enzyme assays, immunohistochemistry, and LC/MS analysis. Diagnostic utility was evaluated ex vivo using clinical specimens and in vivo using a peritoneal dissemination mouse model. ResultsThree probes--EK-HMRG, NA-HMRG and DA-HMRG--were selected as promising candidates for the detection of peritoneal dissemination in HGSC. Puromycin-sensitive aminopeptidase (PSA) was identified as a novel target enzyme of these probes. EK-HMRG, NA-HMRG and DA-HMRG rapidly detected peritoneal dissemination just a few millimeters in size with high sensitivity and specificity in clinical HGSC specimens and in a peritoneal dissemination mouse model after topical application. ConclusionsThe PSA-targeting topical fluorescence probes EK-HMRG, NA-HMRG and DA-HMRG are promising tools for real-time, highly sensitive intraoperative visualization of peritoneal dissemination in HGSC, and are promising candidates to improve complete resection rates.

cancer biology↗

bioRxiv2026

Postnatal Pax7-expressing limb cells are multipotent and generate non-myogenic lineages that persist into adulthood.

Organs are composed of a complex arrangement of diverse cell types that can originate from independent cell lineages or shared progenitors. Skeletal muscle is derived from mesodermal Pax7+ stem/progenitor cells that can differentiate into myoblasts to form muscle fibers. During embryogenesis, however, somitic Pax7+ cells can also give rise to non-muscle cell types, including dermis and adipocytes. Here, we asked whether Pax7+ cells retain such multipotency during early postnatal growth of limb muscles. Using lineage tracing, we uncovered unexpected plasticity at early postnatal days, leading to the generation of multiple non-myogenic lineages, including a previously unrecognized Pax7-derived subpopulation of fibro-adipogenic progenitors that we termed Pax7FAPs and further investigated. Using mouse models, we further show that Notch signaling primes neonatal Pax7+ cells toward a fibrogenic molecular identity at the expense of myogenic differentiation, thereby biasing their trajectory toward a fibrogenic fate. In the adult muscle, long-term tracing revealed that neonatally produced Pax7FAPs persist into adulthood. In addition, injury in adult muscle triggered de novo generation of Pax7FAPs, which displayed higher proliferative capacity than resident stromal cells. This newfound multipotency of postnatal Pax7+ cells adds a new dimension to our understanding of cellular contributions during postnatal muscle development and regeneration.

developmental biology↗

bioRxiv2025

EC-isHCR: a rapid method for in situ hybridization chain reaction in diverse animal samples

The in situ hybridization chain reaction (isHCR) visualizes RNA across multiple spatial scales, from organs to subcellular structures, in diverse samples. We previously proposed a rapid protocol, EC-isHCR, for Drosophila embryos and ovaries. Whether EC-isHCR retains the features of conventional isHCR, including wide-spatial-scale analyses in various samples, however, has remained unclear. Here, we show that EC-isHCR enables robust RNA detection in a broad range of samples, such as whole-mount fruit fly, parasitoid wasp, and aphid preparations; paraffin sections of trout; frozen mouse sections; and human cultured cells. Moreover, EC-isHCR enabled detection of subcellular RNA localization. EC-isHCR also visualized co-localization of RNA with phase-separated condensates in fruit fly embryos and detected the protrusion-enriched mRNA in HeLa cells. To broaden the applicability of EC-isHCR, we developed an automated probe design tool (https://github.com/ShuntaYorimoto/hcrkit). By combining this tool with EC-isHCR, we provide a fast and versatile framework to visualize mRNAs. This framework will help reduce the barrier to using fast isHCR and thereby facilitate research across diverse areas of the life sciences. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=77 SRC="FIGDIR/small/696653v1_ufig1.gif" ALT="Figure 1"> View larger version (25K): org.highwire.dtl.DTLVardef@1852584org.highwire.dtl.DTLVardef@621682org.highwire.dtl.DTLVardef@1b3bf5corg.highwire.dtl.DTLVardef@1d86841_HPS_FORMAT_FIGEXP M_FIG C_FIG Highlights- EC-isHCR enables rapid acquisition of high-contrast images. - EC-isHCR preserves features of conventional isHCR, including versatile sample compatibility and high-resolution imaging. - An automated probe design tool was developed for EC-isHCR. - EC-isHCR/probe tool framework will help reduce the barrier to using fast isHCR.

bioengineering↗

bioRxiv2025

Candidatus Rickettsia mendelii has the smallest and most ancestral-like genome in the genus Rickettsia

Rickettsia species, which constitute obligate intracellular bacteria adapted to a host-dependent lifestyle, have traditionally been classified into four phylogenetic groups. However, the available genomes are biased toward the Typhus and Spotted Fever groups, with early-diverging Ancestral group (AG) lineages being underrepresented. Here, we isolated six Candidatus Rickettsia mendelii strains from Ixodes turdus ticks in Japan. We obtained their whole-genome sequences, including one closed genome, and found that they form a distinct lineage in the AG and have the smallest genome among the known rickettsial species. Gene tree-aware reconstruction of evolutionary events using amalgamated likelihood estimation revealed that the last common ancestor of Rickettsia had a smaller gene family size than modern species do, and Ca. R. mendelii retains the most similar genomic content to this ancestral state. Various patterns of gene gain and loss among Rickettsia lineages were also suggested, highlighting their divergent evolutionary trajectories. These findings increase our understanding of Rickettsia genome evolution.

microbiology↗

bioRxiv2025

A cross-species spatial transcriptomic atlas of the human and non-human primate basal ganglia

The basal ganglia are interconnected subcortical nuclei with complex topographical organization that orchestrate goal-directed behaviors and are implicated in neurodegenerative movement disorders. We generated a cellular-resolution, spatial transcriptomic atlas of the basal ganglia in human, rhesus macaque, and common marmoset, sampling over one million cells in each species. By integrating spatial data with a cross-species, consensus snRNA-seq cell type taxonomy, this atlas reveals conserved principles of molecular organization within and across structures. The cellular architecture is complex but highly stereotyped, with gene expression gradients superimposed onto discrete compartments. Extensive spatial sampling illuminates 3D gradients of molecular organization in the striatum and reveals cell type-specific core and shell compartments in the primate internal globus pallidus, which is conserved with mouse. This unified, cross-species spatial transcriptomic atlas will be a foundational resource for characterizing the molecular and functional organization of the basal ganglia and their roles in health and disease.

neuroscience↗

bioRxiv2025

Muscle stem cells produce a protective Fibrillin-1 matrix to prevent precocious activation.

Multiple biological mechanisms have been uncovered to regulate muscle stem cell quiescence, including inhibition of differentiation, adhesion-dependent anchoring, and translational control, which can be broadly classified as intrinsic or extrinsic properties. Here, we identify the matrix glycoprotein Fibrillin-1 (FBN1) as a Notch-regulated, cell-autonomous effector, essential for maintaining quiescence in muscle stem cells. Known for its causal role in Marfan syndrome (MFS), a connective tissue disorder that also presents with skeletal muscle atrophy, our work positions FBN1 as a critical niche component that protects stem cells from aberrant growth factor signalling. We demonstrate that targeted deletion of Fbn1 in muscle stem cells leads to dose-dependent quiescence defects, characterized by loss of cellular projections, depletion of the stem cell pool, and progressive decline in muscle function. Consistently, human MFS muscle biopsies show abnormally activated satellite cells, implicating stem cell imbalance in the development of MFS-associated myopathy. Mechanistically, the loss of FBN1 upregulates TGF{beta} signalling, and pharmacological inhibition of this pathway using the Angiotensin Receptor blocker losartan restores the cellular and physiological defects of mutant muscles. These findings reveal a new quiescence-preserving mechanism through extracellular matrix-mediated shielding from mitogenic signals, and position stem cell dysfunction as a driver of MFS myopathy. Graphical abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=159 SRC="FIGDIR/small/666604v1_ufig1.gif" ALT="Figure 1"> View larger version (64K): org.highwire.dtl.DTLVardef@1895e71org.highwire.dtl.DTLVardef@1974e87org.highwire.dtl.DTLVardef@a49979org.highwire.dtl.DTLVardef@5813c9_HPS_FORMAT_FIGEXP M_FIG C_FIG Model of Fibrillin-1 protective barrier in quiescent satellite cells.Satellite cells produce Fibrillin-1 (FBN1) to establish a localized extracellular matrix barrier that limits exposure to mitogenic signals. Mechanistically, FBN1 expression is induced by Notch signalling and serves to sequester latent TGF{beta} complexes in an inactive form, thereby preventing their activation within the immediate niche. This barrier is spatially restricted beneath the basal lamina and remains functionally independent from the abundant interstitial FBN1 produced by fibro-adipogenic progenitors (FAPs). The model describes a self-contained, satellite cell-derived ECM system that maintains quiescence by insulating the cells from activating cues.

cell biology↗

bioRxiv2025

Establishment of a green fluorescent protein (GFP)-based reporter for picornaviral 3C proteases

Picornaviruses represent a diverse group of plus-stranded RNA viruses, many of which have been linked to severe diseases in both humans and animals. The viral 3C protease is essential for the maturation of viral proteins and the propagation of picornaviruses and, owing to its cleavage activity against multiple host proteins, is associated with the pathogenesis of picornaviruses. The picornaviral 3C protease is an ideal drug target for inhibiting viral propagation and mitigating pathogenesis; however, methodology to evaluate and compare the activity of phylogenetically diverse proteases remains lacking. To address this, herein, we propose a novel green fluorescent protein (GFP)-based reporter optimized to visualize the enzymatic activity of picornaviral 3C proteases in cells by using the conformational change of a GFP variant induced by the 3C protease, generating fluorescence emission linked to the enzymatic activity. Upon treatment of picornaviruses with a known 3C protease inhibitor, the fluorescence decreased in a dose-dependent manner, demonstrating that the signal depended on the activity of the 3C protease. The reporter system for the 3C protease can be applied to major pathogenic human picornaviruses, such as those in the genera Enterovirus, Rhinovirus, Cosavirus, Salivirus, and Kobuvirus. Furthermore, the fluorescent signal from the reporter was confirmed in various animal- derived picornaviruses, such as those from bats, rodents, and primates. Therefore, the reporter could be widely used to analyze the activity of several 3C proteases from currently prevalent picornaviruses and those that may emerge in the future. To demonstrate the flexibility of the reporter in comparing phylogenetically different proteases, the enzymatic activity of the 3C protease derived from clinical strains of enterovirus A71 (EV-A71) was tested and compared. The results showed that the amino acid residues of the 3C protease affect its activity by utilizing the reporter system. Additionally, clinical EV- A71 strains had different effects on the activity of 3C protease against host proteins. Our findings will aid in elucidating the molecular characteristics of 3C proteases among picornaviruses and developing therapeutics to mitigate the pathogenesis of these viruses.

cell biology↗

bioRxiv2025

Evaluation of anti-noroviral compounds on human norovirus replication using 2D monolayers of human intestinal organoids

We evaluated the anti-noroviral effects of compounds including molnupiravir, on human norovirus (HuNoV) replication using 2D monolayers of human intestinal organoids (HIOs), which have been widely used in HuNoV infection studies. We found that these compounds exhibited lower antiviral activity in 2D HIO monolayers compared with that in apical-out 3D HIOs, a recently developed culture system for HuNoV. This suggests that the anti-noroviral efficacy of these compounds may vary depending on the assay system used.

microbiology↗

bioRxiv2025

Unsupervised feature computation-based feature selection robustly extracted resting-state functional connectivity patterns related to mental disorders

Research on biomarkers for predicting psychiatric disorders from resting-state functional connectivity (FC) is advancing. While the focus has primarily been on the discriminative performance of biomarkers by machine learning, identification of abnormal FCs in psychiatric disorders has often been treated as a secondary goal. However, it is crucial to investigate the effect size and robustness of the selected FCs because they can be used as potential targets of neurofeedback training or transcranial magnetic stimulation therapy. Here, we incorporated approximately 5,000 runs of resting-state functional magnetic resonance imaging from six datasets, including individuals with three different psychiatric disorders (major depressive disorder [MDD], schizophrenia [SCZ], and autism spectrum disorder [ASD]). We demonstrated that an unsupervised feature-computation-based feature selection method can robustly extract FCs related to psychiatric disorders compared to other conventional supervised feature selection methods. We found that our proposed method robustly extracted FCs with larger effect sizes from the validation dataset compared to different types of feature selection methods based on supervised learning for MDD (Cohens d = 0.40 vs. 0.25), SCZ (0.37 vs. 0.28), and ASD (0.17 vs. 0.16). We found 78, 69, and 81 essential FCs for MDD, SCZ, and ASD, respectively, and these FCs were mainly thalamic and motor network FCs. The current study showed that the unsupervised feature-computation-based feature selection method robustly identified abnormal FCs in psychiatric disorders consistently across datasets. The discovery of such robust FCs will contribute to understanding neural mechanisms as abnormal brain signatures in psychiatric disorders. Furthermore, this finding can aid in developing precise therapeutic interventions, such as neurofeedback training or transcranial magnetic stimulation therapy.

neuroscience↗

bioRxiv2025

Development of a 24-Channel 3T Phased-Array Coil for fMRI in Awake Monkeys - Mitigating Spatiotemporal Artifacts in Ferumoxytol-Weighted Functional Connectivity Estimation

Functional magnetic resonance imaging (fMRI) of awake macaque monkeys holds promise for advancing our understanding of primate brain organization, including humans. However, estimating functional connectivity in awake animals is challenging due to the limited duration of imaging sessions and the relatively low sensitivity to neural activity. To overcome these challenges, we developed a 24-channel 3T receive radiofrequency (RF) coil optimized for parallel imaging of awake macaques. This enabled the acquisition of multiband and GRAPPA-accelerated ferumoxytol-weighted resting-state fMRI. The Human Connectome Project-style data processing pipelines were adapted to address the unique preprocessing demands of cerebral blood volume-weighted (CBVw) imaging, including motion correction, functional-to-structural image co-registration, and training a multi-run independent component analysis-based X-noiseifier (ICA-FIX) classifier for removal of structured artifacts. Our CBVw fMRI approach resulted in an elevated contrast-to-noise ratio compared to blood oxygenation level dependent (BOLD) imaging in anesthetized macaques. However, structured imaging artifacts still contributed more variance to the functional timeseries than neural activity. By applying the ICA-FIX classifier, we achieved highly reproducible parcellated functional connectivity at the single-subject level. At the group-level, we identified dense functional networks with spatial features homologous to those observed in humans. The developed RF receive coil, image acquisition protocols, and data analysis pipelines are publicly available, providing the broader scientific community with tools to leverage these advances for further research.

neuroscience↗

bioRxiv2025

Linking neuron-axon-synapse architecture to white matter vasculature using high-resolution multimodal MRI in primate brain

Blood vessels and axons align outside the brain due to shared growth factors. However, this neuron-axon-synapse and vessel relationship within the brain white matter remains unclear, primarily due to the technical challenges of charting the complex trajectories of fiber tracts and the dense network of arteries. Consequently, the organizational logic and neurometabolic factors shaping white matter vasculature remain poorly understood. Here, we address these questions using high-resolution multimodal MRI, in vitro neuron density, and receptor autoradiography in macaque monkeys. In superficial white matter, vascularity exhibited parallel alignment with the cortical surface. This vascularity showed negligible dependence on overlying gray matter neuron density (R2 = 0.01), minimal dependence on white matter myelination (R2 = 0.10), and moderate correlation with receptor density (R2 = 0.27). These suggest an association of vascularity with energy demands and axonal branching. In deep white matter, axon geometry, density, and proximity to the cortical surface predict vascular volume with high precision (R2 = 0.62). Overall, these findings establish a relation between neuron-axon-synapse architecture and white matter vasculature in the primate brain, offering advances in understanding the organization and pathophysiology of white matter.

neuroscience↗

bioRxiv2025

Dietary amino acid manipulations in the common marmoset Callithrix jacchus impacts serum metabolites and FGF21 levels

Restricting dietary protein intake has metabolic and physiological benefits for animals. Rodent studies have identified the involvement of a hormone fibroblast growth factor 21 (FGF21), which is upregulated by sensing amino acid scarcity. However, to what extent this mechanism is conserved in primates remains elusive. Using common marmosets Callithrix jacchus as a non-human primate model, we demonstrate a protocol for protein restriction and dietary amino acid manipulation. Low protein diet induces a decrease in blood urea nitrogen, altered plasma amino acid profiles, and an increase in plasma FGF21. Supplementation of purified amino acids to the diet suppresses plasma features of protein restriction. Our data provide a dietary intervention technique in marmosets and an insight into the evolutionarily conserved mechanism of FGF21 induction during protein restriction.

physiology↗