Biology subjects

Goto, H.

Publications and source records attributed to Goto, H..

12 recordsLinked to original sources

bioRxiv2026

Identification and functional characterization of novel murine DIS3L2 isoforms

RNases are key factors for the posttranscriptional control of gene expression due to their involvement in processing, degradation and quality control of all classes of RNA in eukaryotes. DIS3L2 is an evolutionarily conserved exoribonuclease involved in cytoplasmic RNA degradation pathways that regulate gene expression. Macrophages undergo great change in gene expression of specific genes that allow these cells to perform multiple functions in addition to defense against infection. Here, we analyzed the change in expression of macrophages genes in response to Leishmania major infection, and show evidence that the levels of RNases such as the RNA exosome, XRN1, and DIS3L2, are modulated by the infection. We then identified three DIS3L2 variants that are differentially expressed in murine macrophages and other cell lines. DIS3L2 isoforms show similar RNA binding affinity, but differences in exonucleolytic activity in in vitro assays. Furthermore, we characterized the interactome of the DIS3L2 variants, which shows similarities with respect to ribosomal proteins, but differences that hint at specific functions for each isoform. This work uncovers previously uncharacterized DIS3L2 isoforms that are active, whose functions have yet to be identified.

molecular biology↗

bioRxiv2026

Human settlement drives population divergence of Leishmania guyanensis at the sylvatic-anthropogenic interface

The Amazon is the largest tropical rainforest in the world, and is an important interface between natural rainforest and anthropogenic environments. In the central Amazon region, Leishmania guyanensis is a common agent of cutaneous leishmaniasis (CL), a disfiguring vector-borne disease that circulates between wild mammalian reservoirs and sandfly vectors in sylvatic cycles. People become infected when they interact or disturb this cycle. At present, little is known about the adaptation of Leishmania parasites at the interface between sylvatic and anthropogenic environments. Here, to characterize CL in a transition zone, we conducted a population genomic analysis of 77 Leishmania isolates from human patients living in Manauss outskirts or in highways adjacent to the Brazilian Amazon rainforest. We discovered two L. guyanensis populations; an ancestral sylvatic population occurring in densely forested areas far from the city and a derived population, occurring in areas with lower forest cover closer to the city (the city-proximal population). The genomic divergence between these populations indicates that their separation occurred relatively recently, consistent with human-driven development of a new transmission cycle for CL in the Manaus region. The lack of recent gene flow between these populations indicates that the newer city-proximal population has established a transmission cycle that operates independently from ancestral sylvatic transmission. This provides a striking example of the adaptation of disease transmission to an environment that has been altered by human activity. Significance StatementEmerging infectious diseases often arise at the interface between natural and human-modified environments. One of these important interfaces is the Amazon, the largest rainforest in the world. We analyzed the population genomics of Leishmania guyanensis, the agent of cutaneous leishmaniasis in the Amazon, typically transmitted in sylvatic cycles. Our findings reveal a recent emergence of a L. guyanensis population associated with anthropogenic environment alterations, which is genetically distinct from the ancestral sylvatic lineage. This newly adapted population highlights how landscape change and urban expansion may drive the evolution and emergence of protozoan vector-borne pathogens at the rainforest-urban interface.

evolutionary biology↗

bioRxiv2025

Phosphorylation of Claspin by elF2α kinase protects cells from heat stress

Various biological stresses can induce replication stress, potentially leading to cancer development. Replication checkpoint protects cells against the threat of DNA damages by suspending cell cycle, allowing DNA repair. Chk1 kinase is activated by various stresses and is required for replication checkpoint. An adaptor protein, Claspin, mediates Chk1 activation, but specific mechanisms involved are still unknown. We demonstrate that heat stress induces hyperphosphorylation of Claspin, resulting in Chk1 activation. Claspin phosphorylation is impaired in cells lacking two eIF2 kinases, GCN2 and HRI, which are parts of the integrated stress response (ISR) pathway. Mass spectrometry identified five heat-inducible phosphorylation sites in the C-terminal region of Claspin, and Claspin lacking these sites failed to activate checkpoint. Our data support a model that the unphosphorylated C-terminal tail of Claspin masks its CKBD (Chk1 Binding Domain)-AP (Acidic Patch) domain, preventing it from interacting with Cdc7. Phosphorylation of the tail causes it to dissociate from CKBD-AP and facilitates Cdc7 interaction, leading to increased Chk1 activation. Our findings demonstrate crosstalk between replication checkpoint and ISR pathways, and suggest potential new strategies for cancer therapy.

molecular biology↗

bioRxiv2025

Altered laminin signaling destinates melanocyte reprogramming in vitiligo

Vitiligo is an acquired depigmenting skin disorder characterized by progressive melanocyte loss, but the cellular mechanisms driving this process remain unclear. Here, we identify melanocyte dedifferentiation as a central and reversible pathogenic mechanism in vitiligo. In healthy human skin, melanocytes reside within a basement membrane niche defined by dystroglycan-laminin-211 adhesion. In contrast, vitiligo lesions exhibit aberrant extracellular matrix remodeling, leading to an adhesion switch to integrin 3{beta}1-laminin-332 interactions. This shift promotes melanocyte dedifferentiation via Rho-F-actin-dependent activation of Hippo and MAPK pathways, resulting in c-Jun-mediated transcriptional changes. Dedifferentiated melanocytes lose their pigment-producing identity and acquire neural crest-like features with multilineage potential. Importantly, this process is reversible. Pharmacological inhibition of involved pathways restores melanocyte differentiation and induces repigmentation in both vitiligo mouse models and ex vivo patient skin. Notably, JAK inhibitors also promote redifferentiation independently of immune modulation. These findings uncover melanocyte dedifferentiation as a fundamental driver of vitiligo and a tractable therapeutic target, offering new opportunities for therapeutic intervention.

cell biology↗

bioRxiv2024

Cryo-electron tomography of the actin cytoskeleton and membrane organization during lamellipodia formation using optogenetics

Lamellipodia are sheet-like protrusions essential for migration and endocytosis, yet the ultrastructure of the actin cytoskeleton during lamellipodia formation remains underexplored. Here, we combined the optogenetic tool PA-Rac1 with cryo-ET to enable ultrastructural analysis of newly formed lamellipodia. We successfully visualized lamellipodia at various extension stages, representing phases of their formation. In minor extensions, several unbundled actin filaments formed "Minor protrusions" at the leading edge. For moderately extended lamellipodia, cross-linked actin filaments formed small filopodia-like structures, termed "mini filopodia." In fully extended lamellipodia, filopodia matured at multiple points, and cross-linked actin filaments running nearly parallel to the leading edge increased throughout the lamellipodia. These observations suggest that actin polymerization begins in specific plasma membrane regions, forming mini filopodia that either mature into full filopodia or detach from the leading edge to form parallel filaments. This actin turnover likely drives lamellipodial protrusion, providing new insights into actin dynamics and cell migration.

cell biology↗

bioRxiv2024

Expression of fibroblast activation protein-α in human deep venous thrombus

BackgroundFibroblast activation protein- (FAP), a type-II transmembrane serine protease, is expressed during wound healing, in cancer-associated fibroblasts, and in chronic fibrosing diseases. However, its expression in deep vein thrombus (DVT) remains unclear. Therefore, in this study, we investigated FAP expression and localization in DVT. MethodsFirst, we pathologically accessed aspirated thrombi of patients with DVT (n=14), classifying thrombotic areas as follows; fresh, cellular lysis, endothelialization, fibroblastic reaction. Endothelialization and fibroblastic reaction were defined as organizing reactions. We immunohistochemically examined FAP-expressed areas and expressed cells. Second, we analyzed FAP expression in cultured dermal fibroblasts. ResultsAll the aspirated thrombi showed a mixture of at least three of the four thrombotic areas. Specifically, 83 % of aspirated thrombi showed fresh and organizing reactions within each thrombus. Immunohistochemical expression of FAP was restricted in organizing area. Further, FAP expression in the thrombi was mainly found in vimentin-positive or -smooth muscle actin-positive fibroblasts in double immunofluorescence. Some CD163-positive macrophages also showed FAP expression. FAP mRNA and protein levels significantly increased in cultured fibroblasts with low- proliferative activity under 0.1% fetal bovine serum (FBS) than that in fibroblasts under 10% FBS. Fibroblasts cultured in 10% FBS showed a significant decrease in FAP mRNA levels following supplementation with hemin, but not with thrombin. ConclusionsThe heterogeneous composition of the venous thrombi suggests the existence of a multistep thrombus formation process in human DVT. Further, fibroblasts or myofibroblasts may express FAP in organizing process in DVT. FAP expression may increase in fibroblasts with low-proliferative activity.

pathology↗

bioRxiv2024

Phosphorylation inhibits intramolecular interactions, DNA-binding and protein interactions of Claspin through disordered/ structured conformation transition

Claspin, known to be highly disordered, plays important roles in replication fork progression, initiation and cellular responses to replication stress. However, regulation of its structure and molecular interactions is not completely understood. We show here, through Proximity-Ligation-Assays, the evidence for intramolecular interaction between the N- and C-terminal segments of Claspin, which depends on the Acidic-Patch [AP] segment near its C-terminus. Interaction of Claspin with DNA and replication factors is highly stimulated in {Delta}AP mutant and by prior dephosphorylation. The wild-type Claspin inhibits the helicase activity of MCM in an AP-dependent manner. {Delta}AP and dephosphorylated Claspin exhibit resistance to trypsin digestion compared to wild-type, suggesting the presence of structural domains in the formers. We propose that Claspin is converted from disordered (closed) to structured (open) conformation at initiation, which stimulates its DNA binding and interaction with replication factors and counteracts its helicase inhibitory activity to trigger initiation of DNA replication.

molecular biology↗

bioRxiv2020

Reduced expression of PD-L1 and IDO1 characterises early response to antimonial therapy in cutaneous leishmaniasis patients.

Cutaneous leishmaniasis (CL) is a chronic skin disease caused by Leishmania parasites and in Sri Lanka, CL is caused by L. donovani. Pentavalent antimonials (e.g. sodium stibogluconate; SSG) are first line drugs for CL, despite protracted and painful treatment regimens. Data from animal models indicate that the effectiveness of SSG requires drug-immune synergy, but mechanistic insight from patients is lacking. We studied whole blood and lesion transcriptomes from CL patients in Sri Lanka at presentation and during SSG treatment. In lesions, we identified differential expression of immune-related genes, including immune checkpoint molecules, after the onset of treatment whereas no differentially expressed genes were identified in whole blood. We confirmed reduced lesional PD-L1 and IDO1 protein expression on treatment in a second validation cohort, using digital spatial profiling and quantitative immunohistochemistry. Dual IHC-FISH revealed significantly higher expression of these immune checkpoint molecules on parasite-infected compared to non-infected lesional CD68+ monocytes / macrophages. Crucially, early reduction in PD-L1 but not IDO1 expression was predictive of rate of clinical cure and occurred in parallel with a reduction in parasite load. A multivariate cox proportional hazard model showed that patients with lower PD-L1 expression on treatment were more likely to cure earlier (HR= 4.88). Our data support a model whereby the initial anti-leishmanial activity of antimonial drugs alleviates checkpoint inhibition of T cell immunity, facilitating immune-drug synergism and clinical cure. Our findings demonstrate that PD-L1 expression can be used as an early predictor of clinical response to SSG treatment and support the use of PD-L1 inhibition as adjunct host directed therapy in Sri Lankan CL.

immunology↗

bioRxiv2019

Three-dimensional analysis of β-cell proliferation by a novel mouse model

Inducing {beta}-cell proliferation could inhibit diabetes progression. Many factors have been suggested as potential {beta}-cell mitogens, but their impact on {beta}-cell replication has not been confirmed due to the lack of a standardized {beta}-cell proliferation assay. In this study, we developed a novel method that specifically labels replicating {beta} cells and yields more reproducible results than current immunohistochemical assays. We established a mouse line expressing the fluorescent ubiquitination-based cell cycle indicator (Fucci2a) reporter only in {beta} cells through Cre-mediated recombination under the control of the rat insulin promoter (RIP-Cre;Fucci2aR). Three-dimensional imaging of optically cleared pancreas tissue from these mice enabled the quantification of replicating {beta} cells in islets and morphometric analysis of islets following mitogen treatment. Intravital imaging of RIP-Cre;Fucci2aR mice revealed cell cycle progression of {beta} cells. Thus, this novel mouse line is a powerful tool for spatiotemporal analysis of {beta}-cell proliferation in response to mitogen stimulation.

cell biology↗

bioRxiv2018

The hippocampus encodes delay and value information during delay-discounting decision making

The hippocampus, a region critical for memory and spatial navigation, has been implicated in delay discounting, the decline in subjective reward value when a delay is imposed. However, how delay discounting is encoded in the hippocampus is poorly understood. Here we recorded from the hippocampal CA1 region of mice performing a delay-discounting decision-making task, where delay lengths and reward amounts were changed across sessions, and identified subpopulations of neurons in CA1 which increased or decreased their firing rate during long delays. The activity of both delay-active and -suppressive cells reflected delay length, reward amount, and arm position, however manipulating reward amount differentially impacted the two populations, suggesting distinct roles in the valuation process. Further, genetic deletion of NMDA receptor in hippocampal pyramidal cells impaired delay-discount behavior and diminished delay-dependent activity in CA1. Our results suggest that distinct subclasses of hippocampal neurons concertedly support delay-discounting decision in a manner dependent on NMDA receptor function.

neuroscience↗

bioRxiv2017

BEHAVIORAL VARIABILITY AS A MEASURE OF SUBTLE PHENOTYPIC TRAIT EXPRESSION OF MOUSE EXECUTIVE FUNCTION DISTORTION

Task learning relies on brain executive function (EF), the construct of controlling and coordinating behavior under the everlasting flow of environmental changes. We have previously shown, that a complete knockout of a vertebrate brain-specific pair of gene paralogs (Ntng1/2) distorts the mouse EF, making behavior less predictable (more variable) via the affected working memory and attention (1). In the current study, conditionally targeting either serotonin transporter (5-HTT) or Emx1-expressing neurons, we show that the cell type-specific ablation of Ntng1 within the excitatory circuits of either cortex or thalamus does not have a profound impact on the EF but rather affects its certain modalities, i.e. impulsivity and/or selective attention, modulated by cognitive demand. Several mice of both conditional genotypes simultaneously occupy either top or bottom parameter-specific behavioral ranks, indicative of a subject-unique antagonistic either proficit or deficit of function within the same behavior. Employing genotype-attributable behavior variability as a phenotypic trait, we deduce, that Ntng1-parsed excitatory pathways contribute but do not fully reconstitute the attention-impulsivity phenotypes, associated with the mouse EF deficit. However, complete knockdown of Ntng1/2, and associated with it behavior variability, explains the deficit of executive function and task learning.

animal behavior and cognition↗

bioRxiv2017

Molecular Correlate Of Mouse Executive Function. Top-Down And Bottom-Up Information Flows Complementation By Ntng Gene Paralogs

Executive function (EF) is a regulatory construct of learning and general cognitive abilities. Genetic variations underlying the architecture of cognitive phenotypes are likely to affect EF and associated behaviors. Mice lacking one of Ntng gene paralogs, encoding the vertebrate brain-specific presynaptic Netrin-G proteins, exhibit prominent deficits in the EF control. Brain areas responsible for gating the bottom-up and top-down information flows differentially express Ntng1 and Ntng2, distinguishing neuronal circuits involved in perception and cognition. As a result, high and low cognitive demand tasks (HCD and LCD, respectively) modulate Ntng1 and Ntng2 associations either with attention and impulsivity (AI) or working memory (WM), in a complementary manner. During the LCD Ntng2supported neuronal gating of AI and WM dominates over the Ntng1-associated circuits. This is reversed during the HCD, when the EF requires a larger contribution of cognitive control, supported by Ntng1, over the Ntng2 pathways. Since human NTNG orthologs have been reported to affect human IQ (1), and an array of neurological disorders (2), we believe that mouse Ntng gene paralogs serve an analogous role but influencing brain executive functioning.

animal behavior and cognition↗