Biology subjects

Maruyama, K.

Publications and source records attributed to Maruyama, K..

9 recordsLinked to original sources

bioRxiv2026

Dysregulated flow responses drive pathogenesis in a cellular model of Sturge-Weber syndrome

Vascular diseases comprise a broad spectrum of conditions associated with organ dysfunction, yet how endothelial responses to mechanical forces drive their pathogenesis remains unclear. Sturge-Weber syndrome (SWS), a flow-associated vascular malformation caused by somatic GNAQ mutations, provides a model to investigate this question. Here, using isogenic induced pluripotent stem cell-derived endothelial cells (ECs), perfusable vascular models, and simplified systems under defined flow conditions, we show that SWS ECs exhibited maladaptive responses to laminar flow, including impaired flow alignment, reduced CLDN5 expression, and decreased transendothelial electrical resistance. Importantly, three-dimensional acoustic microscopy uncovered disturbed surface changes in SWS ECs, potentially contributing to changes in mechanosensing signaling. Transcriptomic and chromatin accessibility analyses revealed dysregulated flow-responsive gene programs, some of which were validated in human SWS samples. These findings provide insights into flow-dependent endothelial dysfunction and a framework for therapeutic modulation in SWS and other vascular disorders.

cell biology↗

bioRxiv2025

Efficacy of natural marine sponges as a passive environmental DNA sampler for freshwater fish diversity monitoring

Environmental DNA (eDNA) analysis is a cost-effective and noninvasive tool for species and biodiversity monitoring in aquatic environments. Passive eDNA sampling is a novel alternative to conventional sampling methods such as water filtration. In this study, we examined the efficacy of the sponge skeleton as a passive eDNA sampler for monitoring freshwater fish. The performance of the passive sampling method was compared with that of standard water filtration in a river environment. Five DNA extraction methods were used in three experiments, and a suitable method for DNA extraction from sponge skeleton was identified. Quantitative fish metabarcoding using MiFish primers revealed no significant differences in species richness between the aqueous and passive sampling methods. Although both the sampling methods showed comparable trends in fish community structure, different clusters were identified for water sampling and passive samplers based on the differences in the DNA concentration of each fish species. The fish diversity in the passive samples was comparable among four DNA extraction methods (except for the filtration method) using the direct capture method. Our results demonstrate the efficacy of passive eDNA sampling for monitoring freshwater fish diversity and the potential use of sponge skeletons as absorption materials for passive eDNA samplers.

ecology↗

bioRxiv2025

VEGF-C-mediated Cardiac Lymphangiogenesis Promotes Inflammation Resolution in Autoimmune Acute Myocarditis in Mice

BACKGROUNDAcute myocarditis is an immune-mediated inflammatory disease characterized by myocardial inflammation and edema. Cardiac lymphatic vessels are essential for fluid clearance and immune regulation; however, their role in modulating inflammation in autoimmune myocarditis remains largely unclear. METHODSWe investigated the impact of cardiac lymphangiogenesis using a murine model of experimental autoimmune myocarditis induced by cardiac myosin peptide immunization. Human autopsy samples were analyzed for lymphatic expansion. Mice were treated with VEGF-C C156S, a VEGFR3-specific agonist, beginning one week after immunization. Cardiac lymphangiogenesis, myocardial edema, inflammatory infiltration, fibrosis, and cardiac function were evaluated by immunohistochemistry, echocardiography, gene expression analysis, and water content measurements. RESULTSThe VEGF-C treatment accelerated cardiac lymphangiogenesis, enhanced lymphatic drainage, reduced myocardial edema, and attenuated inflammatory cell infiltration and fibrosis. Echocardiography showed the preservation of left ventricular function. VEGF-C selectively decreased the accumulation of iNOS inflammatory macrophages without broadly suppressing T cells or reparative macrophages. Bulk RNA sequencing confirmed the down-regulation of inflammatory gene signatures associated with macrophage activation. CONCLUSIONSThe early stimulation of cardiac lymphangiogenesis by VEGF-C promotes the resolution of inflammation, reduces myocardial injury, and preserves cardiac function in autoimmune myocarditis. Targeting the cardiac lymphatic system may represent a promising therapeutic strategy for acute myocarditis.

pathology↗

bioRxiv2025

Inhibiting SOX18 with propranolol restores vascular integrity in NR2F2-driven malformations

Translating genomic discoveries into therapies for rare genetic disorders remains a significant challenge, particularly for variants of unknown significance (VUS) where molecular mechanisms are unclear. This is particularly relevant in vascular malformations, where venous differentiation remains poorly understood, and the role of transcription factors in specifying venous identity is only beginning to be elucidated. Here, we combine live-cell single-molecule imaging with genomics-based approaches to uncover a biophysical mechanism of transcription factor antagonism that underpins venous identity. We show that SOX18 and NR2F2 antagonistically co-regulate venous differentiation through dynamic feedback between their nuclear populations. This interaction is disrupted in vascular malformation syndrome caused by a de novo heterozygous NR2F2 mutation, presenting with aberrant vascular integrity and bleeding. Treatment with an FDA-approved drug--known to inhibit SOX18--led to marked clinical improvement in the proband. To dissect the molecular mechanism underlying this mutation and the drug response, we used human embryonic stem cells (hESCs) engineered to carry the probands NR2F2 variant. These cells exhibited impaired hESC to venous differentiation with no effect on artery EC differentiation. In silico modelling and live-cell molecular imaging revealed that the NR2F2 variant is hyper-mobile, fails to form homodimers, and cannot recruit SOX18, thereby disrupting a critical transcriptional antagonism that underpins venous endothelial identity. We demonstrate that targeted pharmacological inhibition of SOX18 restores this regulatory balance in hESC-derived venous endothelial cells, rescuing both gene expression and NR2F2 binding dynamics at the single-molecule level. Together, this study uncovers a biophysical mechanism of transcription factor antagonism that governs venous differentiation and offers a framework for developing targeted therapies for rare vascular malformations.

developmental biology↗

bioRxiv2024

Embryological cellular origins and hypoxia-mediated mechanisms in PIK3CA-Driven refractory vascular malformations

Congenital vascular malformations, affecting 0.5% of the population, often occur in the head and neck, complicating treatment due to the critical functions in these regions. Our previous research identified distinct developmental origins for blood and lymphatic vessels in these areas, tracing them to the cardiopharyngeal mesoderm (CPM), which contributes to the development of the head, neck, and cardiovascular system in both mouse and human embryos. In this study, we investigated the pathogenesis of these malformations by expressing Pik3caH1047R in the CPM. Mice expressing Pik3caH1047R in the CPM developed vascular abnormalities restricted to the head and neck. Single-cell RNA sequencing revealed that Pik3caH1047R upregulates Vegf-a expression in endothelial cells through HIF-mediated hypoxia signaling. Human samples supported these findings, showing elevated HIF-1 and VEGF-A in malformed vessels. Notably, inhibition of HIF-1 and VEGF-A in the mouse model significantly reduced abnormal vasculature. These results highlight the role of embryonic origins and hypoxia-driven mechanisms in vascular malformations, providing a foundation for the development of therapies targeting these difficult-to-treat conditions.

molecular biology↗

bioRxiv2023

Lymphatic vessel development in human embryos

Lymphatic vessel development has been a subject of research for about 120 years. Studies employing mice and zebrafish models have elucidated that lymphatic endothelial cells (LECs) predominantly differentiate from venous endothelial cells via the expression of transcription factor Prospero homeobox protein 1 (Prox1), a master regulator of lymphatic vessel development. On the other hand, it has been found that LECs can also be generated from undifferentiated mesodermal or hemogenic endothelial cells, suggesting potential diversity in their origins depending on the organ or anatomical location. However, knowledge of human lymphatic vessel development remains limited. Here, we examined early lymphatic development in humans by analyzing 31 embryos and three 9-week old fetuses. We found that human embryos produce Prox1-expressing LECs in and around the cardinal veins, which converged to form initial lymph sacs. Furthermore, we also examined lymphatic vessel development in the heart, lungs, lower jaw, mesentery, intestines and kidneys. Lymphatic vessels appeared to develop at different rates in each organ and to display temporal differences in marker expression. These observation showed the possibility that there could exist different patterns of lymphatic vessel development across organs, which may reflect different cellular origins or developmental signaling in each organ. Our research clarifies the early development of human lymphatic vessels, contributing to a better understanding of the evolution and phylogenetic relationships of lymphatic systems, and enriching our knowledge of the role of lymphatics in various human diseases. Significance StatementLymphatic vessel development has been a focus of research for over a century. Recent studies across a variety of species have demonstrated that lymphatic endothelial cells originate from embryonic veins, and undifferentiated mesodermal cells. However, whether these findings are applicable to human has yet to be determined. In this study, we explored lymphatic vessel development in humans. Our analysis demonstrated that lymphatic endothelial cells in human embryos initially derived from embryonic veins. Notably, we found that lymphatic vessels in different organs displayed distinct developmental and marker expression patterns, suggesting a diversity in lymphatic vessel development across organs. Our research revealed the human lymphatic vessel development, contributing to the understanding of phylogenetics of lymphatic vessels and lymph-related diseases.

developmental biology↗

bioRxiv2022

The cardiopharyngeal mesoderm contributes to lymphatic vessel development

Lymphatic vessels are crucial for tissue homeostasis and immune responses in vertebrates. Recent studies have demonstrated that lymphatic endothelial cells (LECs) arise from both venous sprouting (lymphangiogenesis) and de novo production from non-venous origins (lymphvasculogenesis), which is similar to blood vessel formation through angiogenesis and vasculogenesis. However, the contribution of LECs from non-venous origins to lymphatic networks is considered to be relatively small. Here, we identify the Islet1 (Isl1)-expressing cardiopharyngeal mesoderm (CPM) as a non-venous origin of craniofacial and cardiac LECs. Genetic lineage tracing with Isl1-Cre and Isl1-MerCreMer mice suggested that a subset of CPM cells gives rise to LECs. These CPM-derived LECs are distinct from venous-derived LECs in terms of their developmental processes and anatomical locations. Later, they form the craniofacial and cardiac lymphatic vascular networks in collaboration with venous-derived LECs. Collectively, our results demonstrate that there are two major sources of LECs, the cardinal vein and the CPM. As the CPM is evolutionarily conserved, these findings may improve our understanding of the evolution of lymphatic vessel development across species. Most importantly, our findings may provide clues to the pathogenesis of lymphatic malformations, which most often develop in the craniofacial and mediastinal regions.

developmental biology↗

bioRxiv2022

Identification of a novel chalcone reductase gene for isoliquiritigenin biosynthesis in dahlia (Dahlia variabilis)

Butein is one of flavonoids conferring bright yellow flower color and is a precursor of aurone in some species. Butein is synthesized by two steps, 3-malonyl CoA and 4-coumaloyl CoA are converted to isoliquiritigenin in the first step, and then isoliquiritigenin is converted to butein in the second step. In the first step, chalcone synthase (CHS) and chalcone reductase (CHR) catalyze this reaction, however, CHR has been reported for the isoflavone biosynthesis pathway in legumes, and CHR for butein biosynthesis has not yet been isolated. In this study, we report CHR that is evolutionally different gene from legume species is involved in isoliquiritigenin biosynthesis in dahlia. To isolate CHR gene, we conducted comparative RNA-seq analysis between Shukuhai and its butein-loss lateral mutant Rinka. We found DvCHR showed significant difference in expression levels that encodes an aldo-keto reductase (AKR) 13 family protein, which was phylogenetically different from legume CHRs belonging to AKR4A family. Gene expression levels and genotype of DvCHR were correlated with butein accumulation among various dahlia cultivars. Though single over expression of DvCHR was not able to accumulate isoliquiritigenin in tobacco, co-overexpression of DvCHR with a chalcone glucosyltransferase Am4'CGT and a MYB transcription factor CaMYBA successfully induced isoliquiritigenin accumulation. In addition, DvCHR homologous gene expression was detected from butein or aurone accumulating Coreopsideae species but not from non-butein or non-aurone accumulating Asteraceae species. These results indicated DvCHR functions as chalcone reductase for butein biosynthesis in dahlia, and isoliquiritigenin biosynthesis in Coreopsideae species has been developed independently from legume species.

plant biology↗

bioRxiv2021

Electric shock causes fear-like persistent behavioral response in the nematode Caenorhabditis elegans

Behavioral persistency reflects internal brain states, which are the foundations of multiple brain functions. However, experimental paradigms that enable genetic analyses of behavioral persistency and its associated brain functions have been limited. Here we report novel persistent behavioral responses caused by electric stimuli in the nematode Caenorhabditis elegans. When the animals on bacterial food are stimulated by alternating current, their movement speed suddenly increases more than 2-fold, which persists for minutes even after the electric stimulation is terminated. Genetic analyses reveal that multiple types of voltage-gated channels are required for the response, possibly as the sensors, and neuropeptide signaling regulates the duration of the persistent response. Additional behavioral analyses indicate that the animals response to electric shock is scalable and has a negative valence. These properties, along with persistence, have been recently regarded as essential features of emotion, suggesting that the animals response to electric shock may express a form of emotion, such as fear.

neuroscience↗