👤 Noburo Takizawa

Carbon nanotubes (CNTs) are important industrial nanomaterials, yet their manufacture presents potential risks for respiratory exposure among workers. CNTs have a high aspect ratio, which raises concerns that they may cause toxicity similar to that of asbestos. Asbestos is known to activate the NLR family pyrin domain containing 3: NLRP3, a key component of inflammasome. We hypothesized that CNTs promote atherosclerosis by enhancing inflammatory response triggered by inflammasome activation. Treatment of human umbilical vein endothelial cells (HUVECs) with two types of double-walled CNTs (DWCNT; NC2150 and NC2100) resulted in a significant increase in the levels of cytoplasmic agglutination of adapter apoptosis-associated speck-like protein containing a C-terminal caspase recruitment domain (ASC) and the levels of phosphorylated ASC and interleukin (IL)-1β. In addition, DWCNT upregulated the expression of adhesion molecule ICAM-1. Consistent with these in vitro findings, apolipoprotein E-deficient (Apoe Show less

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized by selective motor neuron cell death. A GGGGCC hexanucleotide repeat expansion (HRE) within the chromosome 9 open reading frame 72 (C9orf72) gene is a major causative factor in ALS. This abnormal HRE triggers five types of dipeptide repeat protein (DPR), each composed of two alternating amino acid expressions. Among the DPRs, arginine-rich Poly-PR localizes predominantly to the nucleus, exerting particularly strong toxicity on motor and cortical neurons. Several mechanisms have been proposed for poly-PR-induced neurotoxicity. In this study, poly-PR-expressing NSC34 motor neuron-like cells showed an increase in oxidative stress. Fibroblast growth factor receptor 1 (FGFR1) is known to promote neurogenesis and inhibit apoptosis in neurons. However, its neuroprotective effects against DPR-induced toxicity have not been previously reported. Here, we demonstrated that FGFR1 activation reduced oxidative stress by upregulating nuclear factor erythroid 2-related factor 2 (NRF2) expression. Furthermore, we propose that the increase in NRF2 through FGFR1 activation may result from the alleviation of protein translation impairment. Overall, these findings suggest that FGFR1 activation provides neuroprotection against poly-PR toxicity and may represent a potential therapeutic strategy for ALS. Show less

A GGGGCC hexanucleotide repeat expansion (HRE) within the C9orf72 gene is a major causative factor in amyotrophic lateral sclerosis (ALS). This aberrant HRE results in the generation of five distinct dipeptide repeat proteins (DPRs). Among the DPRs, poly-PR accumulates in the nucleus and exhibits particularly strong toxicity to motor and cortical neurons. Fibroblast growth factor receptor 1 (FGFR1) is known to promote neurogenesis and inhibit apoptosis in neurons. Nevertheless, there has been no previous report of its neuroprotective effects against poly-PR toxicity. The objective of this study was to investigate the neuroprotective effects of FGFR1 activation in poly-PR-expressing NSC34 motor neuron-like cells. RT-qPCR analysis in NSC34 cells showed that Fgfr1 was the most highly expressed member of the Fgfr family in NSC34 cells. The activation of FGFR1 by FGF2, a common ligand for all FGFRs, exerted neuroprotective effects against the toxicity of poly-PR. Additionally, FGFR1 activation was observed to enhance cell viability through the PI3K-AKT pathway, while the contribution of the MEK-ERK pathway was found to be limited. Furthermore, FGFR1 activation suppressed the accumulation of p53 protein and promoted its degradation through increased murine double minute 2 (MDM2), an E3 ubiquitin ligase that targets p53. The neuroprotective effects were attenuated by PD173074, a selective FGFR1 inhibitor or Nutlin-3a, an inhibitor of the p53-MDM2 interaction. Overall, these findings suggest that FGFR1 activation provides neuroprotection against poly-PR toxicity. Consequently, this study suggests the potential utility of FGFR1 activation as a therapeutic strategy for ALS. Show less

Fibrosis is a condition characterized by the overproduction of extracellular matrix (ECM) components (e.g., collagen) in the myofibroblasts, causing tissue hardening and eventual organ dysfunction. Currently, the molecular mechanisms that regulate ECM production in the myofibroblasts are still obscure. In this study, we investigated the function of GPRC5B in the cardiac and lung myofibroblasts using real-time RT-PCR and siRNA-mediated knockdown. We discovered a significantly high expression of Gprc5b in the tissues of the fibrosis mice models and confirmed that Gprc5b was consistently expressed in the myofibroblasts of fibrotic hearts and lungs. We also found that Gprc5b expression was associated and may be dependent on the actin-MRTF-SRF signaling pathway. Notably, we observed that Gprc5b knockdown reduced the expression of collagen genes in the cardiac and lung myofibroblasts. Therefore, our findings reveal that GPRC5B enhances collagen production in the myofibroblasts, which directly promotes fibrosis in the tissues. Show less

Transient ischemic attack (TIA) is a predictor for cerebral infarction (CI), and early diagnosis of TIA is extremely important for the prevention of CI. We set out to identify novel antibody biomarkers for TIA and CI, and detected matrix metalloproteinase 1 (MMP1), chromobox homolog 1 (CBX1), and chromobox homolog 5 (CBX5) as candidate antigens using serological identification of antigens by recombinant cDNA expression cloning (SEREX) and Western blotting to confirm the presence of serum antibodies against the antigens. Amplified luminescent proximity homogeneous assay-linked immunosorbent assay (AlphaLISA) revealed that serum antibody levels were significantly higher in patients with TIA or acute-phase CI (aCI) compared with healthy donors ( Show less

Heterochromatin plays important roles in transcriptional silencing and genome maintenance by the formation of condensed chromatin structures, which determine the epigenetic status of eukaryotic cells. The trimethylation of histone H3 lysine 9 (H3K9me3), a target of heterochromatin protein 1 (HP1), is a hallmark of heterochromatin formation. However, the mechanism by which HP1 folds chromatin-containing H3K9me3 into a higher-order structure has not been elucidated. Here we report the three-dimensional structure of the H3K9me3-containing dinucleosomes complexed with human HP1α, HP1β, and HP1γ, determined by cryogenic electron microscopy with a Volta phase plate. In the structures, two H3K9me3 nucleosomes are bridged by a symmetric HP1 dimer. Surprisingly, the linker DNA between the nucleosomes does not directly interact with HP1, thus allowing nucleosome remodeling by the ATP-utilizing chromatin assembly and remodeling factor (ACF). The structure depicts the fundamental architecture of heterochromatin. Show less

A C↔T single nucleotide polymorphism (SNP) on exon 24 of the porcine class 3 phosphoinositide-3-kinase (PIK3C3) gene is considered a possible genetic marker for selecting backfat (BF) thickness and carcass fat, although only one study has published results on its effects by performing experiments on a single resource family. We analyzed the association of this PIK3C3 polymorphism with production traits in 739 Duroc pigs. The C allele frequency was 67.9% in our study population. PIK3C3 polymorphism showed significant effects on average daily weight gain (ADG), BF thickness, intermuscular fat content (IMF), and the size of the loin eye muscle area (EMA). The C alleles increased ADG, BF and IMF, and decreased EMA. The predicted differences in traits between the homozygous pigs of the C and T alleles were 40 g/day for DG, 1.2 mm for BF, 0.44% for IMF, and 1.6 cm(2) for EMA. Furthermore, the statistical models for estimating the breeding values of each trait had lower Akaike's information criterion values when adding PIK3C3 genotype information. We therefore confirmed that the polymorphism in PIK3C3 (C2604T) has the potential to be a genetic marker for production traits in Duroc pigs. Show less