Biology subjects

Takase, H.

Publications and source records attributed to Takase, H..

9 recordsLinked to original sources

bioRxiv2025

Global hypoperfusion leads to a mismatch in oxygen delivery and consumption in the cerebral watershed area

Despite the pivotal role of pial collaterals in maintaining cerebral blood flow during focal brain ischemia, it is largely unexplored how the microvascular blood flow and oxygenation in the watershed "pial-collateral territory" differ from those in the territory supplied by the major arteries during chronic global hypoperfusion. To answer this question, we applied 2-photon microscopy and Doppler optical coherence tomography to investigate the changes in cerebral microvascular blood flow and partial pressure of oxygen (PO2), induced by bilateral common carotid artery stenosis (BCAS). The measurements were performed in the somatosensory cortex that is supplied by the middle cerebral artery (MCA), and in the adjacent watershed area in the awake, head-restrained C57BL/6 mice, via the chronic cranial window. The results showed that the BCAS induced a larger decrease in capillary red blood cell (RBC) flux in the watershed area than in the MCA territory, especially in the subcortical white matter. Besides, PO2 in the pial collaterals was significantly lower than that in the upstream MCA segments under control conditions. However, the PO2 changes in the arteries and veins under global hypoperfusion displayed different trends in the two interrogated regions, resulting in a significant increase in oxygen extraction fraction in the watershed area. These findings suggest a mismatch between oxygen supply and demand in the watershed area due to global hypoperfusion and increased subcortical white matter vulnerability. We have also observed dilation of the pial collaterals after BCAS, which might suggest a compensatory mechanism to improve the blood flow in the watershed under hypoperfusion.

neuroscience↗

bioRxiv2024

Spatial ciliary signaling regulates the dorsal/ventral regionalization of human brain organoids

Regionalization of the brain is a fundamental question in human developmental biology. Primary cilia are known for a critical organelle for dorsal/ventral fate of brain formation in mice, but little is known about how signaling in the primary cilia regulate regionalization of the human brain. Here, we found that signaling in the primary cilia function in regionalization of the brain using brain organoids derived from human induced pluripotent stem (iPS) cells. Deletion of a ciliary GTPase, ARL13B, induced partially ventralized neural stem cells in the dorsal cortical organoids, despite using a guided dorsal cortical organoid differentiation protocol. Mechanistically, ARL13B knockout (KO) neural stem cells decreased ciliary localization of GPR161, a negative regulator of SHH signaling in primary cilia and increased SONIC HEDGEHOG (SHH) signaling. GPR161 deletion also induced ventralized neural stem cells in the dorsal cortical organoids, despite using the guided differentiation protocol. GPR161 deletion increased SHH signaling mediated by decreased GLI3 repressor formation. Pharmacological treatment to increase cAMP levels rescued GLI3 repressor formation and the differentiation of dorsal neural stem cells in GPR161 KO brain organoids. Importantly, elevating the amount of ciliary cAMP by optogenetics restored the generation of dorsal neural stem cells in GPR161 KO brain organoids. These data indicate that spatial ciliary signaling, the ARL13B-GPR161-cAMP axis in primary cilia, is a fundamental regulator of the dorsal/ventral regionalization of the human brain.

developmental biology↗

bioRxiv2024

MAP4K1 and MAP4K2 regulate ABA-induced and Ca2+-mediated stomatal closure in Arabidopsis

Abscisic acid (ABA)-induced stomatal closure limits water loss from plants under drought stress. To investigate signaling pathways involved in stomatal closure, we performed a phosphoproteomic analysis of ABA-treated Arabidopsis guard cell protoplasts (GCPs). From this analysis, we discovered that MITOGEN-ACTIVATED PROTEIN 4 KINASE 1 (MAP4K1) is phosphorylated in response to ABA. Subsequent biochemical assays showed that Ser-479 of MAP4K1 is directly phosphorylated by SRK2E (OST1/SnRK2.6), a protein kinase that plays a central role in ABA-induced responses. Mutational analyses of MAP4K1, as well as closely related MAP4K2, revealed that both kinases positively regulate ABA-induced stomatal closure, and that Ser-479 of MAP4K1 was required for this phenotype. In map4k1map4k2, stomatal closure was induced by exogenous Ca2+ but not H2O2. Furthermore, electrophysiology experiments showed that MAP4K1/2 are required for ABA-dependent activation of Ca2+-permeable channels in GCPs. Together, our results indicate that SnRK2 and MAP4K1/2 function as a signaling module to regulate Ca2+-mediated stomatal closure.

plant biology↗

bioRxiv2024

Transcriptomic analysis of the juvenile to adult transition in the mouse corpus callosum

The corpus callosum, a major white matter tract in the brain, undergoes age-related functional changes. To extend our investigation of age-related gene expression dynamics in the mouse corpus callosum, we compared RNA-seq data from 2-week-old and 12-week-old wild-type C57BL/6J mice and identified the differentially expressed genes (e.g., Serpinb1a, Ndrg1, Dnmt3a, etc.) between these ages. Interestingly, we found that genes highly expressed in myelinating oligodendrocytes were upregulated in 12-week-old mice compared to 2-week-old mice, while genes highly expressed in oligodendrocyte precursor cells (OPCs) and newly formed oligodendrocytes were downregulated. Furthermore, by comparing these genes with the datasets from 20-week-old and 96-week-old mice, we identified novel sets of genes with age-dependent variations in the corpus callosum. These gene expression changes potentially affect key biological pathways and may be closely linked to age-related neurological disorders, including dementia and stroke. Therefore, our results provide an additional dataset to explore age-dependent gene expression dynamics of oligodendrocyte lineage cells in the corpus callosum.

neuroscience↗

bioRxiv2023

Correlating stress reduction and eye movement patterns in a world famous Kyoto Japanese garden

Visual stimuli have been repeatedly shown to elicit significant non-visual responses. In a continuing effort to explore the unique effects of viewing a Japanese garden on the physiological and psychological metrics of stress, we gained access to the world famous Murin-an garden in Kyoto, Japan. This well-maintained observation garden was designed to be viewed while seated at a single vantage point to maximize the impact of the visual scene. As a control, we used a public garden on the campus of Kyoto University that was designed in a similar style. Sixteen college age students were asked to view both gardens while we monitored their pulse rates and tracked their eye movements. We used the POMS questionnaire to determine the effect of the garden viewing on the mood of the participants. We found that the Murin-an garden was more effective in decreasing pulse rate and improving mood than the University garden. The eye tracking data showed that during their Murin-an viewing the participants gaze ranged far more broadly across the visual field both the X-Y plane and in depth, and the speed with which the eyes moved from point-to-point was greater. Taken together, our data suggest that no one element in the garden was dominant in eliciting the changes in heart rate and mood. Rather, it was the breadth and rapidity of the shifts in gaze that drove the effects, a conclusion with implications for other interventions aimed stress reduction. SignificanceViews of nature and natural phenomena have a well-recognized calming effect on humans that has recognized therapeutic value in both medical and psychological settings. Our work explores the source of this effect by having participants view Murin-an, a world-famous Japanese style garden. Using both psychological and physiological measures, we confirm and extend earlier findings showing that a well constructed garden can effectively lower heart rate and improve mood within minutes. We also find, by analogy with eye movement desensitization and reprograming (EMDR), that it is participants rapidly shifting gaze rather than a single specific visual object is the most likely source of the calming effect.

neuroscience↗

bioRxiv2023

Hyperosmolarity-induced suppression of group B1 Raf-like protein kinases modulates drought-growth trade-off in Arabidopsis

When plants are exposed to drought stress, there is a trade-off between plant growth and stress responses. Here, we identified a signaling mechanism for the initial steps of the drought-growth trade-off. Phosphoproteomic profiling revealed that Raf13, a B1 subgroup Raf-like kinase, is dephosphorylated under drought conditions. Raf13 and the related B1-Raf Raf15 are required for growth rather than the acquisition of osmotolerance. We also found that Raf13 interacts with B55-family regulatory subunits of protein phosphatase 2A (PP2A), which mediates hyperosmolarity-induced dephosphorylation of Raf13. In addition, Raf13 interacts with an AGC kinase INCOMPLETE ROOT HAIR ELONGATION HOMOLOG 1 (IREH1), and Raf13 and IREH1 have similar functions in regulating cellular responses that promote plant growth. Overall, our results support a model in which Raf13-IREH1 activity promotes growth under nonstressed conditions, whereas PP2A activity suppresses Raf13-IREH1 during osmotic stress to modulate the physiological "trade-off" between plant growth and stress responses.

plant biology↗

bioRxiv2022

Apoplast-localized β-Glucosidase Elevates Isoflavone Accumulation in the Soybean Rhizosphere

Plant specialized metabolites (PSMs) are often stored as glycosides within cells and released from the roots with some chemical modifications. While isoflavones are known to function as symbiotic signals with rhizobia and to modulate the soybean rhizosphere microbiome, the underlying mechanisms of root-to-soil delivery are poorly understood. In addition to transporter-mediated secretion, the hydrolysis of isoflavone glycosides in the apoplast by an isoflavone conjugate-hydrolyzing {beta}-glucosidase (ICHG) has been proposed but not yet verified. To clarify the role of ICHG in isoflavone supply to the rhizosphere, we have isolated two independent mutants defective in ICHG activity from a soybean high-density mutant library. In the ichg mutants, the isoflavone contents and composition in the root apoplast and root exudate significantly changed. When grown in a field, the lack of ICHG activity considerably reduced isoflavone aglycone contents in roots and the rhizosphere soil, although the transcriptomes showed no distinct differences between the ichg mutants and WTs. Despite the change in isoflavone contents and composition of the root and rhizosphere of the mutants, root and rhizosphere bacterial communities were not distinctive from those of the WTs. Root bacterial communities and nodulation capacities of the ichg mutants did not differ from the WTs under nitrogen-deficient conditions, either. Taken together, these results indicate that ICHG elevates the accumulation of isoflavones in the soybean rhizosphere but is not essential in isoflavone-mediated plant-microbe interactions.

plant biology↗

bioRxiv2021

Plasma membrane damage limits replicative lifespan in yeast and human fibroblasts

Plasma membrane damage (PMD) occurs in all cell types due to environmental perturbation and cell-autonomous activities. However, cellular outcomes of PMD remain largely unknown except for recovery or death. Here, using budding yeast and normal human fibroblasts, we show that cellular senescence, irreversible cell cycle arrest contributing to organismal aging, is the long-term outcome of PMD. To identify the genes essential for PMD response, we developed a simple PMD-damaging assay using a detergent and performed a systematic yeast genome-wide screen. The screen identified 48 genes. The top hits in the screen are the endosomal sorting complexes required for transport (ESCRT) genes, encoding the well-described plasma membrane repair proteins in eukaryotes. Unexpectedly, the replicative lifespan regulator genes are enriched in our 48 hits. This finding suggests a close genetic association between the PMD response and the replicative lifespan regulations. Indeed, we show that PMD limits the replicative lifespan in budding yeast; the ESCRT activator AAA-ATPase VPS4-overexpression extends it. These results suggest that PMD limits replicative lifespan in budding yeast. Moreover, in normal human fibroblasts, we find that PMD induces premature senescence via the Ca2+-p53 axis but not the major senescence pathway, ATM/ATR pathway. Consistent with the results in yeast, transient overexpression of ESCRT-III, CHMP4B, suppressed the PMD-dependent senescence in normal human fibroblasts. Our study proposes that PMD limits cellular lifespan in two different eukaryotic cell types and highlights an underappreciated but ubiquitous senescent cell subtype, namely PMD-dependent senescent cells.

cell biology↗

bioRxiv2019

MGSE regulates crosstalk from the mucin pathway to the TFE3 pathway of the Golgi stress response

The Golgi apparatus is an organelle where membrane or secretory proteins receive post-translational modifications such as glycosylation and sulfation, after which the proteins are selectively transported to their final destinations through vesicular transport. When the synthesis of secretory or membrane proteins is increased and overwhelms the capacity of the Golgi (Golgi stress), eukaryotic cells activate a homeostatic mechanism called the Golgi stress response to augment the capacity of the Golgi. Four response pathways of the Golgi stress response have been identified, namely the TFE3, CREB3, HSP47, and proteoglycan pathways, which regulate the general function of the Golgi, apoptosis, cell survival, and proteoglycan glycosylation, respectively. Here, we identified a novel response pathway that augments the expression of glycosylation enzymes for mucins in response to insufficiency in mucin-type glycosylation in the Golgi (mucin-type Golgi stress), and we found that expression of glycosylation enzymes for mucins such as GALNT5, GALNT8, and GALNT18 was increased upon mucin-type-Golgi stress. We named this pathway the mucin pathway. Unexpectedly, mucin-type Golgi stress induced the expression and activation of TFE3, a key transcription factor regulating the TFE3 pathway, suggesting that the activated mucin pathway sends a crosstalk signal to the TFE3 pathway. We identified an enhancer element regulating transcriptional induction of TFE3 upon mucin-type Golgi stress, and named it the mucin-type Golgi stress response element, of which consensus was ACTTCC(N9)TCCCCA. These results suggested that crosstalk from the mucin pathway to the TFE3 pathway has an important role in the regulation of the mammalian Golgi stress response.

cell biology↗