Biology subjects

Abe, T.

Publications and source records attributed to Abe, T..

At least 37 records · Page 2Linked to original sources

bioRxiv2025

Identification of an early-heading mutant in Indonesian native rice cultivar: 'Gemdjah Beton'

Rice is one of the worlds most widely cultivated field crops and a short-day adapted plant. It possesses a complex genetic regulatory mechanism for heading date determination. Gemdjah Beton (GB) is an Indonesian rice cultivar that takes approximately 17 weeks to flower after being transplanted into a rice field in Japan. We isolated early-heading mutant line GB-10 (flowers around two to three weeks early in the field). Under long-day (LD) conditions, GB-10 flowered approximately two weeks earlier than GB. Under short-day conditions, the heading date between GB-10 and GB plants shows no apparent difference. In agreement with the heading date, Hd3a and RFT1 expressions show around a 10-time relative transcript quantity difference under LD conditions in GB-10 compared to GB. Interestingly, Ghd7 expression was significantly reduced in GB-10, which may trigger the Hd3a and RFT1 activation. A bulk segregation analysis indicated that a single nucleotide variant on chromosome 7 was genetically linked to the early heading phenotype of GB-10 lines. Taken together, we reported the successful isolation of GB-10 as an early-heading mutant.

plant biology↗

bioRxiv2025

Multimodal Analysis of Sepsis-induced Cardiomyopathy in a Baboon Model

Sepsis-induced cardiomyopathy (SIC) significantly contributes to sepsis-related morbidity and mortality, necessitating a deeper understanding of its mechanisms. This study used a post-hoc, multimodal approach--including single-nucleus RNA sequencing (snRNA-seq), echocardiography, mitochondrial function, and histopathology--to characterize SIC in a non-human primate model. Archived data and samples from six baboons challenged with 37.5 mg/kg of purified peptidoglycan were analyzed. Vital signs and echocardiography were monitored for 8 hours; the endpoint was survival at 168 hours or euthanasia for irreversible organ failure. Septic shock--defined by hypotension, tachycardia, and elevated lactate--was associated with poor outcomes. Echocardiography showed reduced intravascular volume, contraction, stroke volume, and cardiac index. SnRNA-seq revealed distinct transcriptomic profiles: non-survivors exhibited inflammation, mitochondrial dysfunction, and maladaptive remodeling; survivors showed activation of pathways supporting contraction, metabolism, and repair. Cell-type analysis highlighted metabolic dysfunction in cardiomyocytes, TNF/NF-{kappa}B-driven inflammation in endothelial cells, and stress responses in fibroblasts and pericytes. Mitochondrial analysis showed impaired electron transport and disrupted metabolism. Histopathology revealed inflammation and myofibrillar damage, more severe in non-survivors. This model recapitulates key SIC features and supports mechanistic and therapeutic discovery.

pathology↗

bioRxiv2025

Hepatitis C virus NS3/4A protease cleaves SPG20, a key regulator of lipid droplet turnover, to promote lipid droplet formation

ABSTRACTSHepatitis C virus (HCV) assembles in close proximity to lipid droplets (LDs), which play important roles in HCV RNA replication. HCV infection often causes the accumulation of large LDs in hepatocytes. However, the molecular mechanism underlying HCV-induced large LD formation is poorly understood. It has been reported that the SPG20/Spartin protein associates with the LD surface and plays a crucial role in LD turnover by recruiting the ubiquitin ligase Itch to promote the ubiquitin-dependent degradation of adipophilin (ADRP), which protects LDs from lipase-mediated degradation. To elucidate the mechanism underlying HCV-induced large LD formation, we investigated the SPG20 proteins role in LD formation in HCV J6/JFH1-infected Huh-7.5 cells. Immunoblot analysis revealed that HCV infection promoted SPG20 protein cleavage. Transfection of increasing amounts of NS3/4A, but not the inactive NS3/4A mutant, resulted in SPG20 cleavage, implicating the NS3/4A protease in this cleavage. Site-directed mutagenesis suggested that the NS3/4A protease cleaves SPG20 at Cys504 and Cys562. The SPG20 protein was co-immunoprecipitated with the LD-attached protein TIP47. Increasing amounts of NS3/4A protease, but not inactive NS3/4A, decreased the co-precipitation of SPG20 with TIP47. The siRNA-mediated knockdown of Itch in Huh-7.5 cells restored ADRP levels, suggesting that Itch mediates ubiquitylation-dependent ADRP degradation. Immunofluorescence staining of HCV-infected cells revealed that ADRP was localized mainly around LDs in HCV-infected cells, whereas cytosolic ADRP was decreased. We propose that the HCV NS3/4A protease specifically cleaves SPG20 and inhibits Itch-mediated ubiquitin-dependent degradation of LD-associated ADRP, thereby promoting the formation of large LDs. IMPORTANCEHCV infection often promotes the formation of large LDs in HCV-infected cells. However, the molecular mechanism underlying large LD formation is poorly understood. LD turnover is regulated by SPG20, Itch E3 ligase, and ADRP. To elucidate the mechanism underlying the formation of large LDs induced by HCV infection, we investigated the roles of SPG20, Itch, and ADRP in large LD formation. The HCV NS3/4A protease specifically cleaves SPG20 and disrupts Itch recruitment to LD-associated ADRP. Therefore, LD-associated ADRP can escape and protects LDs from lipase-mediated degradation, thereby promoting LD growth. We propose that HCV NS3/4A protease-mediated cleavage of SPG20 contributes to a previously uncharacterized mechanism underlying the formation of large LDs in HCV-infected cells. These findings may lead to a better understanding of how the virus forms large LDs in infected cells.

microbiology↗

bioRxiv2025

Non-DNA-damaging DNA-PK activation improving hearing and prolonging life due to NAD+ and SIRT upregulation

Emerging evidence strongly supports a close relationship between age-related hearing loss and frailty, highlighting the importance of early detection and intervention. Recently, we invented a mitochondria-homing drug named mitochonic acid 5 (MA-5), that increases the adenosine triphosphate (ATP) levels, rescue mitochondrial function, and protect tissue damages. Currently, the phase I clinical trial has been finished in Japan (jRCT2031210495) and the phase 2 clinical trial has already been approved by PMDA. Here we show that MA-5 improved various types of hearing loss in mouse models. Structural chemical bioanalysis revealed that MA-5 is a mixture of equal amount of S- and R- enantiomer and both S- and R- enantiomer increase ATP by binding mitochondrial protein, mitofilin. However, S-enantiomer significantly increased the NAD+ levels by binding to the NAD+-producing key enzyme nicotinamide phosphoribosyltransferase (NAMPT). Moreover, the S-enantiomer increased the sirtuin 1 protein by suppressing polyubiquitination induced by tripartite motif containing 28 (TRIM28) phosphorylation which was triggered by DNA-dependent protein kinase (DNA-PK) activation in the absence of DNA damage. Transcriptomic signatures showed that the signature of MA-5 shows an inverse correlation with aging and mortality and is oriented in the same direction as the OSKM-related iPSCs, suggesting the modification of aging pathways. Oral administration of MA-5 to mitochondrial disease model mouse showed increased survival. Our findings suggest that, in addition to enhancing ATP levels, the coordinated regulation of NAD+ metabolism, SIRT protein expression, and DNA-PK activity-constituting a novel therapeutic triad may contribute to the amelioration of hearing impairment and mitochondrial dysfunction, thereby improving life prognosis.

cell biology↗

bioRxiv2025

Metabolic cell death of labile iron deficiency as a vulnerability of head and neck squamous cancer cells evaded by BACH1

Head and neck squamous cell carcinoma (HNSCC) remains difficult to treat due to the lack of molecularly targeted drugs with high anti-tumor efficacy and safety. To investigate the involvement of the transcription factor BACH1, which is known to promote the metastasis of various cancers, in the malignant properties of HNSCC cells, we examined the effects of BACH1 depletion with short interfering RNAs in human HNSCC cell lines. We found that knockdown of BACH1 induced cell death due to depletion of intracellular labile iron which is not tightly bound to protein. Mitochodrial electron transfer chain activity was severely reduced but efficiently resuced with supplementation of iron in the medium. By combining chromatin immunoprecipitation-sequence and RNA-sequence analyses, we found that BACH1 represses ferritin genes in HNSCC cells. BACH1 knockdown was found to enhance the effect of tipifarnib, a selective inhibitor of farnesyltransferase required for HRAS activation, resulting in efficient inhibition of proliferation of HNSCC cell lines in vitro. These results indicate that BACH1 is essential for maintaining the amount of labile iron in HNSCC cells to evade metabolic cell death of iron deficiency and to proliferate. BACH1 can be a target for conferring Tipifarnib sensitivity to HNSCC cells.

cancer biology↗

bioRxiv2025

HCV infection induces ubiquitin-dependent degradation of LATS1, inactivating the Hippo pathway and upregulating transcription of the CYR61 and CTGF genes

Hepatitis C virus (HCV) is often associated with chronic liver diseases and significant alterations in host cellular signaling. However, the molecular mechanisms underlying HCV- related liver pathogenesis remain to be elucidated. The Hippo signaling pathway, a key regulator of cell proliferation and survival, plays a critical role in maintaining liver homeostasis. Here we investigated the role of the Hippo pathway in HCV-related pathogenesis. We demonstrated that HCV infection induces degradation of LATS1, a key regulator of the Hippo pathway. Degradation of LATS1 protein was restored by a proteasomal inhibitor, but not a lysosome inhibitor, indicating that HCV promotes proteasomal degradation of LATS1 protein. HCV-induced degradation of LATS1 protein was suppressed in si-Itch-transfected Huh-7.5 cells. These results suggest that Itch ubiquitin ligase is involved in ubiquitin-dependent degradation of LATS1 protein. Cell fractionation assays and immunofluorescence staining revealed that HCV infection promoted nuclear translocation of YAP1 protein, suggesting that HCV infection suppresses the Hippo pathway. Furthermore, the transcription of YAP1 target genes, CYR61 and CTGF, that are involved in tissue remodeling and proliferation, was upregulated in HCV-infected Huh-7.5 cells and in HCV-infected patients. Taken together, we propose that HCV promotes the ubiquitin-dependent proteasomal degradation of LATS1 protein, leading to suppression of the Hippo pathway, thereby upregulating transcription of CYR61 and CTGF genes. DATA SUMMARYAll data are presented in the main figures. Raw sequencing data, microscopy images, materials, and sequence information are available upon request. Correspondence and requests for materials should be addressed to Professor Ikuo Shoji. The data that support the findings of this study is available at bioRxiv (https://www.biorxiv.org/). IMPACT STATEMENTWe demonstrate evidence suggesting that HCV infection promotes the Itch-mediated ubiquitin-dependent degradation of LATS1 protein, a key factor for the Hippo pathway. HCV-induced ubiquitin-dependent degradation of LATS1 protein promotes inactivation of the Hippo pathway and nuclear translocation of YAP1 protein, thereby upregulating transcription of CYR61 and CTGF genes. We propose a novel molecular mechanism in which HCV infection promotes degradation of LATS1 protein, leading to inactivation of the Hippo pathway. Understanding HCV-induced inactivation of the Hippo pathway may lead to developing new strategies for preventing or treating HCV-related pathogenesis.

microbiology↗

bioRxiv2025

Longitudinal analysis of antibody titers after primary and booster mRNA COVID-19 vaccination can identify individuals at risk for breakthrough infection

A key issue in the post-COVID-19 era is the ongoing administration of COVID-19 vaccines. Repeated vaccination is essential for preparing against currently circulating and newly emerging SARS-CoV-2 variants while enabling people to continue with daily life. Optimizing vaccination strategies is crucial to efficiently manage medical resources and establish an effective vaccination framework. Therefore, it is important to quantitatively understand vaccine-induced immunity dynamics and to be able to identify poor responders with lower sustained antibody titers as potential priorities for revaccination. We investigated longitudinal antibody titer data in a cohort of 2,526 people in Fukushima, Japan, from April 2021 to November 2022 for whom basic demographic and health information was available. Using mathematical modeling and machine learning, we stratified the time-course patterns of antibody titers after 2 primary doses and 1 booster dose of mRNA COVID-19 vaccines. We identified 3 notable populations, which we refer to as the durable, the vulnerable, and the rapid-decliner populations, approximately half of which remained in the same population after the booster dose. Notably, the rapid-decliner population experienced earlier infections than the others. Furthermore, when comparing IgG(S) titers, IgA(S) titers, and T-spot counts between participants who experienced breakthrough infections after booster vaccination and those who did not, we found that IgA(S) titers were significantly lower in breakthrough infected participants during the early stage after booster vaccination. Our computational approach is adaptable to various types of vaccinations. This flexibility can inform policy decisions on vaccine distribution to enhance immunity both in future pandemics and in the post-COVID-19 era.

immunology↗

bioRxiv2025

Chronic social defeat causes dysregulation of systemic glucose metabolism via the cerebellar fastigial nucleus

Chronic psychological stress leads to hyperglycemia through the endocrine and sympathetic nervous systems, which contributes to the development of type II diabetes mellitus (T2DM). Higher plasma corticosteroids after stress is one well-established driver of insulin resistance in peripheral tissues. However, previous studies have indicated that only a fraction of patients with depression and post-traumatic disorder (PTSD) who develop T2DM exhibit hypocortisolism, so corticosteroids do not fully explain psychological stress-induced T2DM. Here, we find that chronic social defeat stress (CSDS) in mice enhances gluconeogenesis, which is accompanied by a decrease in plasma insulin, an increase in plasma catecholamines, and a drop in plasma corticosterone levels. We further reveal that these metabolic and endocrinological changes are mediated by the activation of neurons projecting from the cerebellar fastigial nucleus (FN) to the medullary parasolitary nucleus (PSol). These neurons are crucial in shifting the bodys primary energy source from glucose to lipids. Additionally, data from patients with depression reveal correlations between the presence of cerebellar abnormalities and both worsening depressive symptoms and elevated HbA1c levels. These findings highlight a previously unappreciated role of the cerebellum in metabolic regulation and its importance as a potential therapeutic target in depression, PTSD, and similar psychological disorders.

neuroscience↗

bioRxiv2025

Quantitative analysis of the frequency of chromosome loss following DSB induction

Numerical abnormalities in chromosomal states, referred to as aneuploidy, is commonly observed in many cancer cells. Although numerous internal and external factors induce aneuploidy, the primary cause of aneuploidy in humans remains unclear. DNA damage is identified as a potential cause of aneuploidy by inducing chromosome segregation errors. However, a direct relationship between DNA damage and aneuploidy remains poorly understood. A major reason for this is the extremely low frequency of aneuploidy in cultured cells, making quantitative analyses challenging. In this study, we investigated the relationship between DNA damage and aneuploidy in cell lines containing minichromosomes. These chromosomes are more prone to loss than normal chromosomes, with the rate of loss substantially increased following exposure to various DNA-damaging agents. To determine whether damaged chromosomes were subjected to direct loss or whether chromosome loss occurred as an indirect consequence of a prolonged G2 phase or other factors, we used the CRISPR-Cas9 system to introduce a single DNA double-strand break (DSB) on a minichromosome. The rate of minichromosome loss increased by approximately seven-fold compared with that of the control. Furthermore, the loss rate was significantly elevated in the absence of KU70, a key factor in non-homologous end joining, and upon inhibition of ataxia telangiectasia mutated (ATM), a DNA damage checkpoint protein. Finally, two closely spaced nicks, believed to generate a 5-overhang, were also shown to induce minichromosome loss. These findings indicated that a single DSB or two closely spaced nicks can cause aneuploidy if improperly repaired in vertebrates.

molecular biology↗

bioRxiv2024

Role Of Pcdh15 In The Development Of Intrinsic Polarity Of Inner Ear Hair Cells

In vertebrates, auditory information is transduced in the cochlea by mechanosensory hair cells (HC) through an eccentrically organised structure known as the hair bundle. This consists of a true cilium, known as the kinocilium, and modified microvilli, known as stereocilia. The hair bundle has a distinct structure with stereocilia organised in graded rows, with the longest abutting the kinocilia. The hair bundles of all HC are aligned to the tissue axis and are planar polarised. Important in the development and physiology of HC are protein bridges consisting of cadherin-23 and protocadherin-15. These link the tips of stereocilia, where they play a role in mechanotransduction, and between the kinocilia and the stereocilia, where they are involved in development. Both cadherin-23 and protocadherin-15 mutations result in defects in planar polarity; however, the mechanism through which this defect arises is unclear. Using a novel mutant for the Pcdh15-CD2 isoform, we show that while the initial deflection of the kinocilium occurs, its peripheral migration to register with Gi3 is perturbed. Pcdh15-CD2 genetically interacts with Gpsm2, perturbing vestibular function. We find that the earliest expression of Pcdh15-CD2 is at the base of the kinocilia, and the defects in morphogenesis occur before the formation of kinocilial links. By re-introducing functional Pcdh15-CD2, we show that polarity can be restored, suggesting that Pcdh15-CD2 couples kinocilial and stereocilial development through a mechanism independent of kinocilial links.

developmental biology↗

bioRxiv2024

Conserved interhemispheric morphogenesis in amniotes preceded the evolution of the corpus callosum

The corpus callosum (CC) is the large axon bundle connecting the telencephalic hemispheres. The CC is formed exclusively in placental mammals, and the lack of comparable structures in other amniotes obscures the evolutionary origin of the CC. We here demonstrate that interhemispheric remodeling, a prior developmental step for CC formation, is highly conserved in non-mammalian amniotes, such as reptiles and birds. In these animal groups, the spatiotemporal dynamics of interhemispheric remodeling are tightly connected with distinct commissural formations. We observed a high degree of similarity between the mammalian CC and reptilian rostral pallial commissure, (RPC) and significant modifications in the avian pallial projection. Furthermore, we determined that Satb2 plays crucial roles in interhemispheric remodeling, which is associated with proper formation of both the CC and RPC in mice and geckoes, via the use of CRISPR-mediated gene-targeting. Our findings suggest that developmental mechanisms for midline remodeling were already present in the common ancestor of amniotes, which contributed to the evolution of eutherian-specific CC formation.

developmental biology↗

bioRxiv2024

Effect of heterozygous deletions on phenotypic changes and dosage compensation in Arabidopsis thaliana

Heterozygous deletions, which include a large number of genes, are often caused by the induction of mutations. The induction of gene dosage compensation should be considered when assessing the effects of heterozygous deletions on phenotypic changes. This mechanism is known to balance the expression levels of genes with different copy numbers in sex chromosomes, but it is also known to operate in autosomes. In the present study, 12 Arabidopsis thaliana BC1 mutants with heterozygous deletions were produced by crossing wild-type Col-0 plants with mutants induced by heavy ion beams. The sizes of the deletions ranged from 50.9 kb to 2.03 Mb, and the number of deleted genes ranged from 8 to 92. Nine of the 12 BC1 mutants showed phenotypic changes in fresh weight 14 days after cultivation or during the flowering period. RNA-sequencing (RNA-seq) analyses of 14-day-old leaves, 40-day-old leaves, and flower buds showed that dosage compensation did not occur in any stage or tissue tested. These results indicate that heterozygous deletions cause phenotypic changes owing to the absence of dosage compensation. Article SummaryIn this study, we examined the impact of heterozygous deletions in Arabidopsis thaliana. By crossing wild-type Col-0 plants with mutants induced by heavy ion beams, we created 12 BC1 mutants, each having heterozygous deletions. The deletions ranged from 50.9 kb to 2.03 Mb, affecting 8 to 92 genes. Nine mutants showed changes in fresh weight or flowering time. RNA-seq analyses of leaves and flower buds revealed no gene dosage compensation. Our findings indicate that phenotypic changes result from the lack of dosage compensation in heterozygous deletions.

genetics↗

bioRxiv2024

A microendovascular system can record precise neural signals from cortical and deep vessels with minimal invasiveness

Minimally invasive intravascular electroencephalography (ivEEG) signals are a promising tool for developing clinically feasible brain-computer interfaces (BCIs) that restore communication and motor functions in paralyzed patients. However, current ivEEG techniques can only record signals from the superior sagittal sinus (SSS), making it challenging to record motor responses related to hand and mouth movements from brain regions distant from the SSS, despite their critical role in BCIs. Here, using micro intravascular electrodes, ivEEGs recorded from the cortical or deep veins of eight pigs could measure cortical activities with greater signal power and better spatial resolution than those recording in the SSS, thus allowing mapping of the sensorimotor and visual functional areas. Additionally, electrical stimulation in the cortical vein between the micro intravascular electrodes induced muscle contractions contralateral to the stimulated area in five anesthetized pigs. These results demonstrate that ivEEG using micro intravascular electrodes is a promising tool for developing BCIs.

neuroscience↗

bioRxiv2024

Transcriptomic Hallmarks of Mortality Reveal Universal and Specific Mechanisms of Aging, Chronic Disease, and Rejuvenation

Health is strongly affected by aging and lifespan-modulating interventions, but the molecular mechanisms of mortality regulation remain unclear. Here, we conducted an RNA-seq analysis of mice subjected to 20 compound treatments in the Interventions Testing Program (ITP). By integrating it with the data from over 4,000 rodent tissues representing aging and responses to genetic, pharmacological, and dietary interventions with established survival data, we developed robust multi-tissue transcriptomic biomarkers of mortality, capable of quantifying aging and change in lifespan in both short-lived and long-lived models. These tools were further extended to single-cell and human data, demonstrating common mechanisms of molecular aging across cell types and species. Via a network analysis, we identified and annotated 26 co-regulated modules of aging and longevity across tissues, and developed interpretable module-specific clocks that capture aging- and mortality-associated phenotypes of functional components, including, among others, inflammatory response, mitochondrial function, lipid metabolism, and extracellular matrix organization. These tools captured and characterized acceleration of biological age induced by progeria models and chronic diseases in rodents and humans. They also revealed rejuvenation induced by heterochronic parabiosis, early embryogenesis, and cellular reprogramming, highlighting universal signatures of mortality, shared across models of rejuvenation and age-related disease. They included Cdkn1a and Lgals3, whose human plasma levels further demonstrated a strong association with all-cause mortality, disease incidence and risk factors, such as obesity and hypertension. Overall, this study uncovers molecular hallmarks of mammalian mortality shared across organs, cell types, species and models of disease and rejuvenation, exposing fundamental mechanisms of aging and longevity.

systems biology↗

bioRxiv2024

Hypothalamic prostaglandins facilitate recovery from hypoglycemia but exacerbate recurrent hypoglycemia in mice

The hypothalamus monitors blood glucose levels and regulates glucose production in the liver. In response to hypoglycemia, glucose-inhibited (GI) neurons trigger counter-regulatory responses (CRRs), which stimulate the release of glucagon, epinephrine, and cortisol to elevate blood glucose. Recurrent hypoglycemia (RH), however, reduces the effectiveness of these CRRs. This study examined the role of hypothalamic prostaglandins in glucose recovery during acute hypoglycemia and RH. Using imaging mass spectrometry and liquid chromatography/mass spectrometry, phospholipid and prostaglandin levels in the hypothalamus of C57BL mice were increased following insulin or 2-deoxy-glucose administration. Ibuprofen, a nonsteroidal anti-inflammatory drug (NSAID), was infused into the ventromedial hypothalamus (VMH) to analyze its effect on glucose production during hypoglycemia, revealing that prostaglandin inhibition decreased glucagon secretion. Additionally, RH-treated mice decreased glucagon release and glucose production during hypoglycemia. Inhibiting prostaglandin production via short-hairpin RNA against cytosolic phospholipase A2 (cPLA2) in the hypothalamus restored CRRs diminished by RH via increasing glucagon sensitivity. These findings suggest that hypothalamic prostaglandins play a critical role in glucose recovery from acute hypoglycemia by activating VMH neurons and are also crucial for the attenuation of CRRs during RH. Graphical Abstract O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=110 SRC="FIGDIR/small/600540v2_ufig1.gif" ALT="Figure 1"> View larger version (23K): org.highwire.dtl.DTLVardef@9e2cf0org.highwire.dtl.DTLVardef@984c29org.highwire.dtl.DTLVardef@b04e6borg.highwire.dtl.DTLVardef@ec6dd3_HPS_FORMAT_FIGEXP M_FIG C_FIG Article HighlightsO_LIInsulin decreases arachidonic acid-containing phospholipids and increases prostaglandin production in the hypothalamus. C_LIO_LIProstaglandin in the hypothalamus increases glucagon secretion and glucose production during hypoglycemia. C_LIO_LIRecurrent hypoglycemia decreases glucagon secretion and glucose production during hypoglycemia. C_LIO_LIProstaglandin in the hypothalamus during recurrent hypoglycemia decreases glucagon sensitivity and glucose production. C_LI

neuroscience↗

bioRxiv2024

Visualization of intracellular ATP dynamics in the whole kidney under pathophysiological conditions using the kidney slice culture system

ATP depletion plays a central role in the pathogenesis of kidney diseases. Recently, we reported spatiotemporal intracellular ATP dynamics during ischemia reperfusion (IR) using GO-ATeam2 mice systemically expressing an ATP biosensor. However, observation from the kidney surface did not allow visualization of deeper nephrons or accurate evaluation of ATP synthesis pathways. Here we established a novel ATP imaging system using slice culture of GO-ATeam2 mouse kidneys, evaluated ATP synthesis pathway, and analyzed intracellular ATP dynamics using ex vivo IR and cisplatin nephropathy models. We demonstrated that proximal tubules (PTs) were strongly dependent on oxidative phosphorylation (OXPHOS), whereas podocytes relied on both OXPHOS and glycolysis using ATP synthesis inhibitors. We also confirmed that the ex vivo IR model could recapitulate ATP dynamics in vivo; ATP recovery in PTs after reperfusion varied depending on ischemia length, whereas ATP in distal tubules (DTs) recovered well even after long ischemia. After cisplatin administration, ATP levels in PTs decreased first, followed by a decrease in DTs. An organic cation transporter 2 inhibitor suppressed cisplatin uptake in kidney slices, leading to better ATP recovery in PTs, but not in DTs. Finally, we confirmed that a mitochondria protection reagent delayed cisplatin-induced ATP decrease in PTs. This novel system may provide new insights into the energy dynamics and pathogenesis of kidney disease.

molecular biology↗

bioRxiv2024

Parallel Labeled-Line Organization of Sympathetic Outflow for Selective Organ Regulation in Mice

The sympathetic nervous system is vital in maintaining homeostasis and responding to environmental changes1-3. This regulation is coordinated by the spinal sympathetic preganglionic neurons (SPNs), which influence various organs both through neuronal pathways via postganglionic neurons and through endocrine processes by innervating the adrenal gland. Despite decades of research supporting the concept of selective control within this system1,4-9, the neural circuit organization responsible for the specificity of sympathetic outflow remains poorly understood. Notably, classical anatomical studies in rats have not revealed a definitive molecular code governing SPNs, nor have they confirmed the existence of SPNs strictly corresponding to specific output targets1,6,10,11. To reconcile this discrepancy, we aim to integrate recent transcriptome data of SPNs12,13 in mice with viral-genetic toolkits14 to map axonal projections and manipulate the functions of SPNs governing the gastrointestinal tract and adrenal gland. Here, we have identified two subtypes of SPNs in the lower thoracic spinal cord, defined at the molecular level, exhibiting non-overlapping patterns of innervation. Chemogenetic manipulations on these distinct SPN subtypes revealed selective impacts on the digestive functions in the gastrointestinal tracts or glucose metabolism mediated by the adrenal gland, respectively. This molecularly delineated parallel labeled-line organization in sympathetic outflows presents a potential avenue for selectively manipulating organ functions.

neuroscience↗

bioRxiv2023

The cadmium-hypertolerant fern, Athyrium yokoscense, exhibits two cadmium stress mitigation strategies in the roots and the aerial parts

Athyrium yokoscense is hypertolerant to cadmium (Cd) and can grow normally under a high Cd concentration despite Cd being a highly toxic heavy metal. To mitigate Cd stress in general plant species, Cd is promptly chelated with a thiol compound and is isolated into vacuoles. Generated active oxygen species (ROS) in the cytoplasm are removed by reduced glutathione. However, we found many differences in the countermeasures in A. yokoscense. Thiol compounds accumulated in the stele of the roots, although a long-term Cd exposure induced Cd accumulation in the aerial parts. Synchrotron radiation-based X-ray fluorescence (SR-XRF) analysis indicated that a large amount of Cd was localized in the cell walls of the roots. Overexpression of AyNramp5a, encoding a representative Fe and Mn transporter of A. yokoscense, increased both Cd uptake and iron and manganese uptake in rice calli under the Cd exposure conditions. Organic acids were abundantly detected in A. yokoscense roots. Investigating the chemical forms of the Cd molecules by X-ray absorption fine structure (XAFS) analysis detected many compounds with Cd-oxygen (Cd-O) binding in A. yokoscense roots, whereas in the aerial parts, the ratio of the compounds with Cd-sulfur (Cd-S) binding was increased. Together, our results imply that the strong Cd tolerance of A. yokoscense is an attribute of the following two mechanisms: Cd-O compound formation in the cell wall is a barrier to reduce Cd uptake into aerial parts. Thiol compounds in the region of root stele are involved in detoxication of Cd by formation of Cd-S compounds. Statements and DeclarationsNo potential conflict of interest was reported by the authors.

plant biology↗