受賞区分：国内学会・会議・シンポジウム等の賞 

担当区分：筆頭著者   記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1371/journal.pone.0316417

記述言語：英語   掲載種別：研究論文（学術雑誌）  

DOI： 10.1016/j.jpet.2024.100052

記述言語：英語   出版者・発行元：Nature Structural and Molecular Biology  

Eukaryotic translation initiation factor (eIF)4A—a DEAD-box RNA-binding protein—plays an essential role in translation initiation. Recent reports have suggested helicase-dependent and helicase-independent functions for eIF4A, but the multifaceted roles of eIF4A have not been fully explored. Here we show that eIF4A1 enhances translational repression during the inhibition of mechanistic target of rapamycin complex 1 (mTORC1), an essential kinase complex controlling cell proliferation. RNA pulldown followed by sequencing revealed that eIF4A1 preferentially binds to mRNAs containing terminal oligopyrimidine (TOP) motifs, whose translation is rapidly repressed upon mTORC1 inhibition. This selective interaction depends on a La-related RNA-binding protein, LARP1. Ribosome profiling revealed that deletion of EIF4A1 attenuated the translational repression of TOP mRNAs upon mTORC1 inactivation. Moreover, eIF4A1 increases the interaction between TOP mRNAs and LARP1 and, thus, ensures stronger translational repression upon mTORC1 inhibition. Our data show the multimodality of eIF4A1 in modulating protein synthesis through an inhibitory binding partner and provide a unique example of the repressive role of a universal translational activator.

DOI： 10.1038/s41594-024-01321-7

Web of Science

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PubMed

記述言語：英語   掲載種別：研究論文（学術雑誌）   出版者・発行元：Developmental and Comparative Immunology  

The initial defense against invading pathogenic microbes is the activation of innate immunity by binding of pattern recognition receptors (PRRs) to pathogen associated molecular patterns (PAMPs). To explain the action of PRRs from hagfish, one of the extant jawless vertebrates, we purified the GlcNAc recognition complex (GRC) from serum using GlcNAc-agarose. The GRC comprises four proteins of varying molecular masses: 19 kDa, 26 kDa, 27 kDa, and 31 kDa. Exposure of Escherichia coli to the GRC led to the phagocytic activation of macrophages, revealing the opsonic function of the GRC. The GRC in serum formed a large complex with a molecular mass of approximately 1200 kDa. The GRC bound to Escherichia coli but not to rabbit red blood cells, despite both having GlcNAc on their surface. These structural and binding properties are similar to those of mannose-binding lectin (MBL). The amino acid sequence of a portion of the 31 kDa protein in the GRC matched the amino acid sequence of variable lymphocyte receptor (VLR)-B in some place. According to the Western blot analysis, the 31 kDa protein was recognized by the anti-hagfish VLR-B antiserum. Based on the results, it appears that the GRC functions as a PRR like MBL and that its 31 kDa protein has a structure similar to that of VLR-B.

DOI： 10.1016/j.dci.2023.105065

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Scopus

PubMed

記述言語：英語   出版者・発行元：Journal of Inflammation Research  

Background: Acute lung injury (ALI) is caused by a variety of illnesses, including aspiration pneumonia and sepsis. The CCR4-NOT complex is a large multimeric protein complex that degrades mRNA through poly(A) tail shortening, whereas it also contributes to regulation of transcription and translation. Cnot3 is a scaffold component of the CCR4-NOT complex and is essential for the integrity of the complex; loss of Cnot3 leads to depletion of whole complex. While the significance of cytokine mRNA degradation in limiting inflammation has been established, the roles of CCR4-NOT complex-mediated in ALI remain elusive. Methods: The effects of Cnot3 haploinsufficiency in the pathology and cytokine expression were analyzed in the mouse lungs of acid aspiration-induced acute lung injury. The decay rate and transcription activity of cytokine mRNAs under Cnot3 heterozygous deletion were analyzed in lipopolysaccharide (LPS)-stimulated mouse embryonic fibroblasts (MEFs). Results: Tamoxifen-induced heterozygous deletion of Cnot3 in adult mice (Cnot3 Hetz) did not show body weight loss or any apparent abnormality. Under acid aspiration-induced acute lung injury, Cnot3 Hetz mice exhibited increased pulmonary edema, worse lung pathologies and more severe inflammation compared with wild type mice. mRNA expression of pro-inflammatory genes Il1b and Nos2 were significantly upregulated in the lungs of Cnot3 Hetz mice. Consistently, mRNA expression of Il1b and Nos2 was upregulated in LPS-stimulated Cnot3 Hetz MEFs. Mechanistically, while heterozygous depletion of Cnot3 stabilized both Il1b and Nos2 mRNAs, the nascent pre-mRNA level of Il1b was upregulated in Cnot3 Hetz MEFs, implicating Cnot3-mediated transcriptional repression of Il1b expression in addition to destabilization of Il1b and Nos2 mRNAs. PU.1 (Spi1) was identified as a causative transcription factor to promote Il1b expression under Cnot3 haploinsufficient conditions. Conclusion: CNOT3 plays a protective role in ALI by suppressing expression of pro-inflammatory genes Il1b and Nos2 through both post-transcriptional and transcriptional mechanisms, including mRNA stability control of Spi1.

DOI： 10.2147/JIR.S468612

Web of Science

Scopus

PubMed

開催年月日： 2023年12月

記述言語：日本語   会議種別：シンポジウム・ワークショップ パネル（公募）  

開催地：神戸市 神戸国際会議場   国名：日本国  

Angiotensin-converting enzyme 2 (ACE2) is the carboxypeptidase that degrades angiotensin II (Ang II) and improves the pathologies of cardiovascular disease and acute respiratory distress syndrome (ARDS)/acute lung injury. B38-CAP, a carboxypeptidase derived from Paenibacillus sp. B38, is an ACE2-like enzyme to decrease angiotensin II levels in mice and ameliorates hypertension and heart failure (Nat Commun. 2020). Here we show the therapeutic effects of B38-CAP on acute lung injury induced by abdominal sepsis, acid aspiration, or SARS_CoV2 infection. ACE2 expression was downregulated in the lungs of hamsters with SARS-CoV2 infection, or the lungs of mice with cecal ligation puncture (CLP)-induced sepsis or acid-induced lung injury thereby leading to upregulation of Ang II levels. Intraperitoneal injection of B38-CAP decreased Ang II levels and suppressed the pathologies of lung inflammation, improved lung dysfunction, and downregulated elevated cytokine mRNA levels in acute lung injury in these animal models. Thus, systemic treatment with an ACE2-like enzyme might be a potential therapeutic strategy for patients with severe sepsis or ARDS (Nat Commun. 2021; PLoS One. 2022).

開催年月日： 2025年3月

記述言語：英語   会議種別：口頭発表（一般）  

開催年月日： 2025年1月 - 2025年2月

記述言語：日本語   会議種別：口頭発表（一般）  

開催年月日： 2024年12月

記述言語：日本語   会議種別：口頭発表（一般）  

開催年月日： 2024年11月

会議種別：口頭発表（一般）  

種別：大会・シンポジウム等 

種別：大会・シンポジウム等