Biology subjects

Ueno, A.

Publications and source records attributed to Ueno, A..

7 recordsLinked to original sources

bioRxiv2024

Afadin-deficient retinas exhibit severe neuronal lamination defects but preserve visual functions

Neural lamination is a common feature of the central nervous system (CNS), with several subcellular structures, such as adherens junctions (AJs), playing a role in this process. The retina is also heavily laminated, but it remains unclear how laminar formation impacts retinal cell morphology, synapse integrity, and overall retinal function. In this study, we demonstrate that the loss of afadin, a key component of AJs, in mice leads to significant pathological changes. These include the disruption of outer retinal lamination and a notable decrease as well as mislocalization of photoreceptors, their outer segments, and photoreceptor synapses. Interestingly, despite these severe impairments, we recorded small local field potentials, including the a- and b-waves. We also classified retinal ganglion cells (RGCs) into ON, ON-OFF, and OFF types based on their firing patterns in response to light stimuli. Additionally, we successfully characterized the receptive fields of certain RGCs. Overall, these findings provide evidence that retinal circuit function can be partially preserved even when there are significant disruptions in both retinal lamination and photoreceptor synapses. Our results indicate that retinas with severely altered morphology still retain some capacity to process light stimuli.

neuroscience↗

bioRxiv2024

Anemia and tissue hypoxia are major determinants of malarial hypelactatemia

Hyperlactatemia, a key marker of severe malaria, is closely linked to increased mortality, though the exact mechanisms remain unclear. It may result from increased lactate production due to tissue hypoxia or reduced lactate clearance from organ dysfunction. This study used Plasmodium yoelii 17XL (Py17XL) murine model of severe malaria, which closely mimics hyperlactatemia seen in human cases, to investigate the contributions of severe anemia and infection-related organ dysfunction to hyperlactatemia. Non-infectious anemia models were also included for comparison. Anemia was found to elevate lactate in both malaria-infected and non-infectious models, but Py17XL infected mice showed higher lactate levels, indicating that anemia alone doesnt fully explain hyperlactatemia. Evidence of tissue hypoxia, particularly in the liver, kidney, and gut, was seen with hypoxyprobe staining and upregulated hypoxia-inducible factor 1-alpha (HIF-1), suggesting that hypoxia drives increased glycolysis and lactate production. Impaired lactate clearance may also play a role, as infected mice showed signs of liver and kidney dysfunction accompanied by reduced clearance of 13C3-labeled sodium-L-Lactate. Whole blood transfusion combined with artesunate significantly improved lactate clearance compared to artesunate alone, underscoring the importance of addressing anemia in treatment. A link between intestinal damage and hyperlactatemia was suggested by correlations between trefoil factor 3 (TFF3), a marker of gut injury, and lactate levels in human samples. Our findings highlight the multifactorial origin of hyperlactatemia in malaria, driven primarily by anemia and tissue hypoxia, pointing to the need for therapies targeting both aspects to reduce mortality in severe cases.

pathology↗

bioRxiv2024

Regulation of ROP GTPase cycling between active/inactive states is essential for vegetative organogenesis in Marchantia polymorpha

Rho/Rac of plant (ROP) GTPases are a plant-specific subfamily of Rho small GTP-binding proteins that function as molecular switches by being converted to the active state by guanine nucleotide exchange factors (GEFs) and to the inactive state by GTPase-activating proteins (GAPs). The bryophyte Marchantia polymorpha contains single-copy genes encoding ROP (MpROP), two types of GEFs (ROPGEF and SPIKE (SPK)), and two types of GAPs (ROPGAP and ROP enhancer (REN)). MpROP regulates the development of various organs, including the air chambers, rhizoids, and clonal propagule gemmae. While the sole PRONE-type ROPGEF, KARAPPO (MpKAR), plays an essential role in gemma initiation, little is known about the in-planta functions of other ROP regulatory factors in M. polymorpha. In this study, we focused on the functions of two types of GAPs: MpROPGAP and MpREN. Loss-of-function Mprenge single mutants showed pleiotropic defects in thallus growth, air chamber formation, rhizoid tip growth, and gemma development, whereas MpROPGAP mutants showed no detectable abnormalities. Despite the distinctive domain structures of MpROPGAP and MpREN, MpropgapgeMprenge double mutants showed more severe phenotypes than the Mprenge single mutants, suggesting redundant functions of MpROPGAP and MpREN in gametophyte organogenesis. Interestingly, overexpression of MpROPGAP, MpREN, and dominant-negative MpROP (MpROPDN) resulted in similar air chamber defects, as well as loss-of-function of MpREN and MpROPGAP and overexpression of constitutively active MpROP (MpROPCA), suggesting importance of activation/inactivation cycling (or balancing) of MpROP. Furthermore, we proved the contributions of the sole DOCK family GEF, MpSPK, to MpROP-regulated air chamber formation. In summary, our results demonstrate a significant role of the two GAPs in the development of various organs and that the two GEFs are responsible for organogenesis through the control of the MpROP active/inactive cycle in the vegetative growth of M. polymorpha.

plant biology↗

bioRxiv2022

Intranasal vaccination induced cross-protective secretory IgA antibodies against SARS-CoV-2 variants with reducing the potential risk of lung eosinophilic immunopathology

To control the coronavirus disease 2019 (COVID-19) pandemic, there is a need to develop vaccines to prevent infection with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants. One candidate is a nasal vaccine capable of inducing secretory IgA antibodies in the mucosa of the upper respiratory tract, the initial site of infection. However, regarding the development of COVID-19 vaccines, there is concern about the potential risk of inducing lung eosinophilic immunopathology as a vaccine-associated enhanced respiratory disease as a result of the T helper 2 (Th2)-dominant adaptive immune response. In this study, we investigated the protective effect against virus infection induced by intranasal vaccination of recombinant trimeric spike protein derived from SARS-CoV-2 adjuvanted with CpG oligonucleotides, ODN2006, in mouse model. The intranasal vaccine combined with ODN2006 successfully induced not only systemic spike-specific IgG antibodies, but also secretory IgA antibodies in the nasal mucosa. Secretory IgA antibodies showed high protective ability against SARS-CoV-2 variants (Alpha, Beta and Gamma variants) compared to IgG antibodies in the serum. The nasal vaccine of this formulation induced a high number of IFN-{gamma}-secreting cells in the draining cervical lymph nodes and a lower spike-specific IgG1/IgG2a ratio compared to that of subcutaneous vaccination with alum as a typical Th2 adjuvant. These features are consistent with the induction of the Th1 adaptive immune response. In addition, mice intranasally vaccinated with ODN2006 showed less lung eosinophilic immunopathology after viral challenge than mice subcutaneously vaccinated with alum adjuvant. Our findings indicate that intranasal vaccine adjuvanted with ODN2006 could be a candidate that can prevent the infection of antigenically different variant viruses, reducing the risk of vaccine-associated enhanced respiratory disease.

microbiology↗

bioRxiv2020

Evaluation of SARS-CoV-2 neutralizing antibodies using a vesicular stomatitis virus possessing SARS-CoV-2 spike protein

SARS-CoV-2 is a novel coronavirus that emerged in 2019 and is now classified in the genus Coronavirus with closely related SARS-CoV. SARS-CoV-2 is highly pathogenic in humans and is classified as a biosafety level (BSL)-3 pathogen, which makes manipulating it relatively difficult due to its infectious nature. To circumvent the need for BSL-3 laboratories, an alternative assay was developed that avoids live virus and instead uses a recombinant VSV expressing luciferase and possesses the full length or truncated spike proteins of SARS-CoV-2. Furthermore, to measure SARS-CoV-2 neutralizing antibodies under BSL2 conditions, a chemiluminescence reduction neutralization test (CRNT) for SARS-CoV-2 was developed. The neutralization values of the serum samples collected from hospitalized patients with COVID-19 or SARS-CoV-2 PCR-negative donors against the pseudotyped virus infection evaluated by the CRNT were compared with antibody titers determined from an immunofluorescence assay (IFA). The CRNT, which used whole blood collected from hospitalized patients with COVID-19, was also examined. As a result, the inhibition of pseudotyped virus infection was specifically observed in both serum and whole blood and was also correlated with the results of the IFA. In conclusion, the CRNT for COVID-19 is a convenient assay system that can be performed in a BSL-2 laboratory with high specificity and sensitivity for evaluating the occurrence of neutralizing antibodies against SARS-CoV-2.

microbiology↗

bioRxiv2020

Subtelomeric regions and a repeat-rich chromosome harbor multicopy effector gene clusters with variable conservation in multiple plant pathogenic Colletotrichum species

Members of the Colletotrichum gloeosporioides species complex are causal agents of anthracnose in a wide range of commercially important plants. To provide an in-depth overview of its diversity, we sequenced the genomes of fungi belonging to this group, including multiple strains of C. fructicola (Cf) and C. siamense (Cs), as well as representatives of three previously unsequenced species, C. aenigma (Ca), C. tropicale and C. viniferum. Comparisons between multiple Cf and Cs strains led to the identification of accessory regions that show variable conservation in both lineages. These accessory regions encode effector candidate genes, including homologs of previously characterized effectors, organized in clusters of conserved synteny with copy number variations in different strains of Cf, Cs and Ca. Analysis of highly contiguous assemblies of Cf, Cs and Ca strains revealed the association of such accessory effector gene clusters with subtelomeric regions and repeat-rich minichromosomes and provided evidence of gene transfer between these two genomic compartments. In addition, expression analysis indicated that paralogs associated with clusters of conserved synteny showed a tendency for correlated gene expression. These data highlight the importance of subtelomeric regions and repeat-rich chromosomes to the genome plasticity of Colletotrichum fungi.

genomics↗

bioRxiv2017

Trans-omic analysis reveals fed and fasting insulin signal across phosphoproteome, transcriptome, and metabolome

The concentration and temporal pattern of insulin selectively regulate multiple cellular functions. To understand how insulin dynamics are interpreted by cells, we constructed a trans-omic network of insulin action in FAO hepatoma cells from three networks--a phosphorylation-dependent cellular functions regulatory network using phosphoproteomic data, a transcriptional regulatory network using phosphoproteomic and transcriptomic data, and a metabolism regulatory network using phosphoproteomic and metabolomic data. With the trans-omic regulatory network, we identified selective regulatory networks that mediate differential responses to insulin. Akt and Erk, hub molecules of insulin signaling, encode information of a wide dynamic range of dose and time of insulin. Down-regulated genes and metabolites in glycolysis had high sensitivity to insulin (fasting insulin signal); up-regulated genes and dicarboxylic acids in the TCA cycle had low sensitivity (fed insulin signal). This integrated analysis enables molecular insight into how cells interpret physiologically fed and fasting insulin signals.\n\nHighlightsO_LIWe constructed a trans-omic network of insulin action using multi-omic data.\nC_LIO_LIThe trans-omic network integrates phosphorylation, transcription, and metabolism.\nC_LIO_LIWe classified signaling, transcriptome, and metabolome by sensitivity to insulin.\nC_LIO_LIWe identified fed and fasting insulin signal flow across the trans-omic network.\nC_LI

systems biology↗