ILF2は骨髄腫細胞において変異原であるAPOBEC3BのDNAシトシン脱アミノ化酵素活性を促進する

京都大学新制・課程博士博士(医学)甲第24187号医博第4881号京都大学大学院医学研究科医学専攻(主査)教授 伊藤 貴浩, 教授 滝田 順子, 教授 小川 誠司学位規則第4条第1項該当Doctor of Medical ScienceKyoto UniversityDFA

Reaction Behavior of a Silicide Electrode with Lithium in an Ionic-Liquid Electrolyte

Silicides are attractive novel active materials for use in the negative-electrodes of next-generation lithium-ion batteries that use certain ionic-liquid electrolytes; however, the reaction mechanism of the above combination is yet to be clarified. Possible reactions at the silicide electrode are as follows: deposition and dissolution of Li metal on the electrode, lithiation and delithiation of Si, which would result from the phase separation of the silicide, and alloying and dealloying of the silicide with Li. Herein, we examined these possibilities using various analysis methods. The results revealed that the lithiation and delithiation of silicide occurred

APOBEC3B is preferentially expressed at the G2/M phase of cell cycle

APOBEC3B (A3B) is a cytosine deaminase that converts cytosine to uracil in single-stranded DNA. Cytosine-to-thymine and cytosine-to-guanine base substitution mutations in trinucleotide motifs (APOBEC mutational signatures) were found in various cancers including lymphoid hematological malignancies such as multiple myeloma and A3B has been shown to be an enzymatic source of mutations in those cancers. Although the importance of A3B is being increasingly recognized, it is unclear how A3B expression is regulated in cancer cells as well as normal cells. To answer these fundamental questions, we analyzed 1276 primary myeloma cells using single-cell RNA-sequencing (scRNA-seq) and found that A3B was preferentially expressed at the G2/M phase, in sharp contrast to the expression patterns of other APOBEC3 genes. Consistently, we demonstrated that A3B protein was preferentially expressed at the G2/M phase in myeloma cells by cell sorting. We also demonstrated that normal blood cells expressing A3B were also enriched in G2/M-phase cells by analyzing scRNA-seq data from 86, 493 normal bone marrow mononuclear cells. Furthermore, we revealed that A3B was expressed mainly in plasma cells, CD10+ B cells and erythroid cells, but not in granulocyte-macrophage progenitors. A3B expression profiling in normal blood cells may contribute to understanding the defense mechanism of A3B against viruses, and partially explain the bias of APOBEC mutational signatures in lymphoid but not myeloid malignancies. This study identified the cells and cellular phase in which A3B is highly expressed, which may help reveal the mechanisms behind carcinogenesis and cancer heterogeneity, as well as the biological functions of A3B in normal blood cells

CAGE-Seq Reveals that HIV-1 Latent Infection Does Not Trigger Unique Cellular Responses in a Jurkat T Cell Model

The cure for HIV-1 is currently stalled by our inability to specifically identify and target latently infected cells. HIV-1 viral RNA/DNA or viral proteins are recognized by cellular mechanisms and induce interferon responses in virus-producing cells, but changes in latently infected cells remain unknown. HIVGKO contains a green fluorescent protein (GFP) reporter under the HIV-1 promoter and a monomeric Kusabira orange 2 (mKO2) reporter under the internal elongation factor alpha (EF1α) promoter. This viral construct enables direct identification of both productively and latently HIV-1-infected cells. In this study, we aim to identify specific cellular transcriptional responses triggered by HIV-1 entry and integration using cap analysis of gene expression (CAGE). We deep sequenced CAGE tags in non-infected and latently and productively infected cells and compared their differentially expressed transcription start site (TSS) profiles. Virus-producing cells had differentially expressed TSSs related to T-cell activation and apoptosis compared to those of non-infected cells or latently infected cells. Surprisingly, latently infected cells had only 33 differentially expressed TSSs compared to those of non-infected cells. Among these, SPP1 and APOE were downregulated in latently infected cells. SPP1 or APOE knockdown in Jurkat T cells increased susceptibility to HIVGKO infection, suggesting that they have antiviral properties. Components of the phosphatidylinositol 3-kinase (PI3K)/mammalian target of rapamycin (mTOR) pathway, MLST8, 4EBP, and RPS6, were significant TSSs in productively infected cells, and S6 kinase (S6K) phosphorylation was increased compared to that in latently infected cells, suggesting that mTOR pathway activity plays a role in establishing the latent reservoir. These findings indicate that HIV-1 entry and integration do not trigger unique transcriptional responses when infection becomes latent

Intratracheal trimerized nanobody cocktail administration suppresses weight loss and prolongs survival of SARS-CoV-2 infected mice

新型コロナウイルスを中和するアルパカ抗体 --マウス実験で有効性を確認--. 京都大学プレスリリース. 2023-02-17.BACKGROUND: SARS-CoV-2 Omicron variants are highly resistant to vaccine-induced immunity and human monoclonal antibodies. METHODS: We previously reported that two nanobodies, P17 and P86, potently neutralize SARS-CoV-2 VOCs. In this study, we modified these nanobodies into trimers, called TP17 and TP86 and tested their neutralization activities against Omicron BA.1 and subvariant BA.2 using pseudovirus assays. Next, we used TP17 and TP86 nanobody cocktail to treat ACE2 transgenic mice infected with lethal dose of SARS-CoV-2 strains, original, Delta and Omicron BA.1. RESULTS: Here, we demonstrate that a novel nanobody TP86 potently neutralizes both BA.1 and BA.2 Omicron variants, and that the TP17 and TP86 nanobody cocktail broadly neutralizes in vitro all VOCs as well as original strain. Furthermore, intratracheal administration of this nanobody cocktail suppresses weight loss and prolongs survival of human ACE2 transgenic mice infected with SARS-CoV-2 strains, original, Delta and Omicron BA.1. CONCLUSIONS: Intratracheal trimerized nanobody cocktail administration suppresses weight loss and prolongs survival of SARS-CoV-2 infected mice

Promotion of allergic immune responses by intranasally-administrated nanosilica particles in mice

With the increase in use of nanomaterials, there is growing concern regarding their potential health risks. However, few studies have assessed the role of the different physical characteristics of nanomaterials in allergic responses. Here, we examined whether intranasally administered silica particles of various sizes have the capacity to promote allergic immune responses in mice. We used nanosilica particles with diameters of 30 or 70 nm (nSP30 or nSP70, respectively), and conventional micro-sized silica particles with diameters of 300 or 1000 nm (nSP300 or mSP1000, respectively). Mice were intranasally exposed to ovalbumin (OVA) plus each silica particle, and the levels of OVA-specific antibodies (Abs) in the plasma were determined. Intranasal exposure to OVA plus smaller nanosilica particles tended to induce a higher level of OVA-specific immunoglobulin (Ig) E, IgG and IgG1 Abs than did exposure to OVA plus larger silica particles. Splenocytes from mice exposed to OVA plus nSP30 secreted higher levels of Th2-type cytokines than mice exposed to OVA alone. Taken together, these results indicate that nanosilica particles can induce allergen-specific Th2-type allergic immune responses in vivo. This study provides the foundations for the establishment of safe and effective forms of nanosilica particles

Effect of amorphous silica nanoparticles on in vitro RANKL-induced osteoclast differentiation in murine macrophages

Amorphous silica nanoparticles (nSP) have been used as a polishing agent and/or as a remineralization promoter for teeth in the oral care field. The present study investigates the effects of nSP on osteoclast differentiation and the relationship between particle size and these effects. Our results revealed that nSP exerted higher cytotoxicity in macrophage cells compared with submicron-sized silica particles. However, tartrate-resistant acid phosphatase (TRAP) activity and the number of osteoclast cells (TRAP-positive multinucleated cells) were not changed by nSP treatment in the presence of receptor activator of nuclear factor κB ligand (RANKL) at doses that did not induce cytotoxicity by silica particles. These results indicated that nSP did not cause differentiation of osteoclasts. Collectively, the results suggested that nanosilica exerts no effect on RANKL-induced osteoclast differentiation of RAW264.7 cells, although a detailed mechanistic examination of the nSP70-mediated cytotoxic effect is needed

Association of antithrombin with development of trauma-induced disseminated intravascular coagulation and outcomes

IntroductionTrauma activates the innate immune system to modulate hemostasis and minimize the damage caused by physiological bodily responses, including the activation of coagulation. Sufficiently severe trauma overwhelms physiological responses and elicits the systemic inflammatory response syndrome, which leads to the onset of disseminated intravascular coagulation (DIC), characterized by dysregulated inflammatory coagulofibrinolytic responses. Impaired anticoagulant mechanisms, including antithrombin, constitutes the pathology of DIC, while the dynamics of antithrombin and relevance to outcomes in trauma-induced coagulopathy have not been fully elucidated. This study investigated the associations of antithrombin activity with DIC onset and outcomes in severely injured patients.MethodsThis retrospective sub-analysis of a multicenter, prospective study included patients with an injury severity score ≥16. We characterized trauma patients with low antithrombin activity (antithrombin <80% on hospital arrival, n = 75) in comparison with those who had normal antithrombin activity (antithrombin ≥80%, n = 200). Global markers of coagulation and fibrinolysis, molecular biomarkers for thrombin generation (soluble fibrin [SF]), and markers of anticoagulation (antithrombin) were evaluated to confirm the associations of antithrombin with DIC development and outcomes, including in-hospital mortality and the multiple organ dysfunction syndrome (MODS).ResultsPatients with low antithrombin activity had higher prevalence of shock, transfusion requirements, and in-hospital mortality. Higher DIC scores and more severe organ dysfunction were observed in the low AT group compared to that in the normal AT group. Antithrombin activity on arrival at the hospital was an independent predictor of the development of DIC in trauma patients, and levels of SF increased with lower antithrombin values (antithrombin activity > 85%). Antithrombin activity at 3 h showed good predictive performance for in-hospital mortality, and a multivariable Cox proportional-hazard regression model with a cross-product term between the antithrombin and DIC showed that the in-hospital mortality in patients with DIC increased with decreased antithrombin activity. A multivariable logistic regression model showed that the odds for the development of MODS in patients with DIC increased with lower antithrombin values.ConclusionDecreased antithrombin activity in trauma-induced coagulopathy is associated with poor outcomes through worsening of DIC