Publications by authors named "Honda Hiroaki"

Certain somatic mutations provide a fitness advantage to hematopoietic stem cells and lead to clonal expansion of mutant blood cells, known as clonal hematopoiesis (CH). Among the most common CH mutations, ASXL1 mutations pose the highest risk for cardiovascular diseases (CVDs), yet the mechanisms by which they contribute to CVDs are unclear. Here we show that hematopoietic cells harboring C-terminally truncated ASXL1 mutant (ASXL1-MT) accelerate the development of atherosclerosis in Ldlr mice.

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  • PRC2 is an important protein complex that modifies DNA to regulate gene expression by adding methyl groups to histone proteins, specifically H3K27.
  • Researchers studied the role of PRC2 in iNKT cell development by deleting a crucial component, Eed, in mouse T cells, which resulted in fewer iNKT cells, particularly NKT1 and NKT17 subtypes.
  • Eed-deficient mice not only showed impaired iNKT cell differentiation and increased cell death but also displayed heightened sensitivity to liver damage caused by acetaminophen, emphasizing the importance of PRC2 in immune response and liver health.
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Immune checkpoint inhibitors (ICIs) exert clinical efficacy against various types of cancers by reinvigorating exhausted CD8 T cells that can expand and directly attack cancer cells (cancer-specific T cells) among tumor-infiltrating lymphocytes (TILs). Although some reports have identified somatic mutations in TILs, their effect on antitumor immunity remains unclear. In this study, we successfully established 18 cancer-specific T cell clones, which have an exhaustion phenotype, from the TILs of four patients with melanoma.

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  • The genome faces constant DNA damage from both internal and external sources, requiring precise regulation of repair mechanisms to maintain integrity.
  • After exposure to ionizing radiation (IR), the modification of histone H3 (H3K4me3) shows a decrease shortly after and an increase later, indicating the dynamic response of chromatin to DNA damage in both human and mouse cells.
  • PTIP, a critical component of a histone methyltransferase complex, is necessary for the upregulation of H3K4me3 and helps induce cell cycle arrest by activating the PRDM1 cell cycle inhibitor, with its reduced expression linked to acute myeloid leukemia.
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  • Metabolic pathways adapt quickly to stress, impacting cell behavior, especially in rare hematopoietic stem cells (HSCs).
  • Researchers focused on how key enzymes affect glycolytic metabolism in HSCs under different conditions.
  • They identified that the enzyme phosphofructokinase (PFK) plays a crucial role in increasing glycolysis during stress, with its regulation influenced by specific modifications, ultimately affecting HSC proliferation and differentiation.
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Rev1 has two important functions in the translesion synthesis pathway, including dCMP transferase activity, and acts as a scaffolding protein for other polymerases involved in translesion synthesis. However, the role of Rev1 in mutagenesis and tumorigenesis in vivo remains unclear. We previously generated Rev1-overexpressing (Rev1-Tg) mice and reported that they exhibited a significantly increased incidence of intestinal adenoma and thymic lymphoma (TL) after N-methyl-N-nitrosourea (MNU) treatment.

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  • - The study investigates reserve cells in the gastrointestinal tract, focusing on their ability to regenerate after tissue damage and whether they exist as long-term resting cells.
  • - Researchers found a population of long-term slow-cycling cells in the gastric corpus, specifically a subpopulation of chief cells, that show unique markers associated with cellular stress and regeneration.
  • - Inducing damage to the gastric mucosa with indomethacin causes these quiescent cells to proliferate, suggesting they play a crucial role in stomach regeneration.
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  • - The study investigates the role of MBTD1, a protein important in hematopoietic stem cells (HSCs), showing it is vital for maintaining HSC quantity and functionality, particularly in fetal development.
  • - Researchers created conditional knockout mice to explore MBTD1's influence on adult HSCs, finding that its absence led to increased HSC numbers but caused defects in stress response and cell cycle regulation.
  • - The findings suggest that MBTD1 helps maintain the quiescence of HSCs by interacting with the FOXO3a protein; restoring FOXO3a in deficient HSCs corrected the observed abnormalities, establishing MBTD1 as key in regulating HSC pool size and health.
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UTX/KDM6A, a histone H3K27 demethylase and a key component of the COMPASS complex, is frequently lost or mutated in cancer; however, its tumor suppressor function remains largely uncharacterized in multiple myeloma (MM). Here, we show that the conditional deletion of the X-linked Utx in germinal center (GC) derived cells collaborates with the activating Braf mutation and promotes induction of lethal GC/post-GC B cell malignancies with MM-like plasma cell neoplasms being the most frequent. Mice that developed MM-like neoplasms showed expansion of clonal plasma cells in the bone marrow and extramedullary organs, serum M proteins, and anemia.

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BCR/ABL1 causes dysregulated cell proliferation and is responsible for chronic myelogenous leukemia (CML) and Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph1-ALL). In addition to the deregulatory effects of its kinase activity on cell proliferation, BCR/ABL1 induces genomic instability by downregulating BRCA1. PARP inhibitors (PARPi) effectively induce cell death in BRCA-defective cells.

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Dysfunctional anti-tumor immunity has been implicated in the pathogenesis of mature B cell neoplasms, such as multiple myeloma and B cell lymphoma; however, the impact of exhausted T cells on disease development remains unclear. Therefore, the present study investigated the features and pathogenetic significance of exhausted T cells using a mouse model of de novo mature B cell neoplasms, which is likely to show immune escape similar to human patients. The results revealed a significant increase in PD-1 Tim-3 and PD-1 Tim-3 T cells in sick mice.

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Salivary glands develop through epithelial-mesenchymal interactions and are formed through repeated branching. The Crk-associated substrate protein (p130Cas) serves as an adapter that forms a complex with various proteins via integrin and growth factor signaling, with important regulatory roles in several essential cellular processes. We found that p130Cas is expressed in ductal epithelial cells of the submandibular gland (SMG).

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Rheumatoid arthritis (RA) is one of the most common autoimmune diseases and affects almost 1% of the population. Differentiated embryo-chondrocyte expressed gene-1 (DEC1) has been associated with both osteogenesis and osteoclastogenesis. RA condition is marked by inflammatory hyperplasia, and DEC1 is known to support inflammatory reactions and implicated in antiapoptosis and cell invasion.

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Recent studies have demonstrated that epigenetic modifications are deeply involved in neurogenesis; however, the precise mechanisms remain largely unknown. To determine the role of UTX (also known as KDM6A), a demethylase of histone H3K27, in neural development, we generated Utx-deficient mice in neural stem/progenitor cells (NSPCs). Since Utx is an X chromosome-specific gene, the genotypes are sex-dependent; female mice lose both Utx alleles (Utx ), and male mice lose one Utx allele yet retain one Uty allele, the counterpart of Utx on the Y chromosome (Utx ).

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  • - Duchenne muscular dystrophy (DMD) is a genetic disorder that causes muscle damage, and the research explores in utero cell transplantation as a potential treatment option.
  • - The study involved transplanting GFP-positive myoblasts and adipose-derived stem cells into pregnant mice (murine DMD models) using different methods but failed to detect any successful cell integration in muscle tissues.
  • - Results indicated that both transplantation methods did not lead to cell engraftment, with adipose-derived stem cell transplants associated with a higher mortality rate in the fetuses.
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A20 (Tnfaip3), a ubiquitin-editing enzyme, inhibits NF-κB signaling pathways in response to pro-inflammatory cytokines. Previous studies have proved the anti-inflammatory roles of A20 in various cell types, including T cells, B cells, dendritic cells, and intestinal epithelial cells. Moreover, recent studies have shown that A20 expressed in lung epithelial cells is required for LPS-induced protection from asthma.

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The basic helix-loop-helix transcriptional factor, Bhlhe40 has been shown as a crucial regulator of immune response, tumorigenesis, and circadian rhythms. We identified Bhlhe40 as a possible regulator of osteoclast differentiation and function by shRNA library screening and found that Bhlhe40 was required for osteoclast activation. Bhlhe40 expression was induced in bone marrow macrophages (BMMs) by RANKL, whereas the expression of its homolog Bhlhe41 was decreased in osteoclastogenesis.

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  • Detailed analysis shows that genetic rearrangements of chromosome 3 drive certain myeloid leukemias by increasing EVI1 transcription through enhancer changes.
  • A novel EVI1 RNA variant, created by mutations in the splicing factor SF3B1, contributes to acute myeloid leukemia transformation and is frequently found in these patients.
  • Mutant SF3B1 promotes abnormal EVI1 splicing, enhancing stem cell self-renewal and accelerating leukemia development in mouse models, highlighting a crucial link between splicing mutations and myeloid leukemia pathogenesis.
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Colorectal cancer (CRC) is the second deadly and the third most common malignancy worldwide. It has been projected that annual new cases of CRC will increase by 63% in 2040, constituting an even greater health challenge for decades to come. This study has linked DEC1 (differentiated embryonic chondrocyte expressed gene 1) to the pathogenesis of CRC.

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Purpose: Anorectal malformations are associated with other organ malformations. Proximodistal elongation of the cloacal plate and anal opening at its distal end are essential for anal development. However, the anal developmental stage in which Wnt5a is directly involved remains unelucidated.

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Amelogenesis consists of secretory, transition, maturation, and post-maturation stages, and the morphological changes of ameloblasts at each stage are closely related to their function. p130 Crk-associated substrate (Cas) is a scaffold protein that modulates essential cellular processes, including cell adhesion, cytoskeletal changes, and polarization. The expression of p130Cas was observed from the secretory stage to the maturation stage in ameloblasts.

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The pathogenesis of allergic contact dermatitis (ACD) requires the activation of Ag-specific T cells, including effector and regulatory T cells. The differentiation and function of these T cells is epigenetically regulated through DNA methylation and histone modifications. However, the roles of altered histone H3K27 methylation in T cells in the development of ACD remain unknown.

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