シロイヌナズナの継世代的DNAメチル化動態におけるゲノムワイドの負のフィードバック

学位の種別: 課程博士審査委員会委員 : （主査）東京大学教授 福田 裕穂, 東京大学教授 平野 博之, 東京大学教授 武田 洋幸, 東京大学教授 角谷 徹仁, 東京大学准教授 阿部 光知University of Tokyo(東京大学

LOW BMI IS THE RISK OF CARDIO-VASCULAR MORTALITY WITHOUT PROGRESSION OF CKD

The paradoxical risk of BMI on mortality is known in CKD as well in dialysis populations, but studies of CVD risk in CKD including underweight is limited. We hypothesized lean CKD increase the CVD risk, contributing different factors from obese. 2,676 CKD patients recruited from 11 outpatients’ hospitals. BMI and estimated GFR (eGFR) were calculated, and change of eGFR and CVD mortality during 2 years were collected. Patients were divided by BMI under cut off value of normal, thus 7% grouped in lean subjects (BMI <18.5). Systolic blood pressure (sBP), albumin, hemoglobin, age and prevalence of diabetes were lower in lean BMI group compared to other subjects. However CVD history, urinary protein, baseline eGFR and smoking didn't differ between the groups. The lean BMI increased significantly the risk of CVD mortality, in spite of low prevalence of comorbidities and young age in unadjusted model (HR 2.38, 95%CI 1.49-5.21, p<0.01). This significance remained after adjusted for CVD risk factors, such as primary disease of CKD, age, sex, smoking, albumin, cholesterol, sBP and eGFR. On the other hand, BMI was not associated with the decline rate of eGFR. We concluded that BMI less than 18.5 was an independent predictor of CVD, and that BMI did not effect on CKD progression rate in Japanese CKD

ROTUNDIFOLIA4 Regulates Cell Proliferation Along the Body Axis in Arabidopsis Shoot

Molecular genetics has been successful in identifying leaf- size regulators such as transcription factors, phytohormones, and signal molecules. Among them, a ROTUNDIFOLIA4-LIKE/DEVIL (RTFL/DVL) family of Arabidopsis, genes encoding peptides with no secretion-signal sequence, is unique in that their overexpressors have a reduced number of leaf cells specifically along the proximodistal axis. However, because the RTFL/DVL lack any obvious homology with functionally identified domains, and because of genetic redundancy among RTFL/DVL, their molecular and developmental roles are unclear. In this study we focused on one member in the family, ROTUNDIFOLIA4 (ROT4), and identified the core functional region within it and we found no proteolytic processing in planta. Developmental analysis of leaf primordia revealed that ROT4 overexpression reduces the meristematic zone size within the leaf blade. Moreover, induced local overexpression demonstrated that ROT4 acts as a regulator of the leaf shape via a change in positional cue along the longitudinal axis. Similarly, ROT4 overexpression results in a protrusion of the main inflorescence stem, again indicating a change in positional cue along the longitudinal axis. These results suggest that ROT4 affects the positional cue and cell proliferation along the body axis

Extracellular Release of HMGB1 as an Early Potential Biomarker for the Therapeutic Response in a Xenograft Model of Boron Neutron Capture Therapy

Boron neutron capture therapy (BNCT) is a non-invasive therapeutic technique for treating malignant tumors, however, methods to evaluate its therapeutic efficacy and adverse reactions are lacking. High mobility group box 1 (HMGB1) is an inflammatory molecule released during cell death. Therefore, we aimed to investigate HMGB1 as a biomarker for BNCT response, by examining the early responses of tumor cells to 10B-boronophenylalanine (BPA)-based BNCT in the Kyoto University Nuclear Reactor. Extracellular HMGB1 release was significantly increased in human squamous carcinoma SAS and melanoma A375 cells 24 h after neutron irradiation but not after γ-irradiation. At 3 days post-BPA-based BNCT irradiation in a SAS xenograft mouse model, plasma HMGB1 levels were higher than those in the non-irradiation control, and HMGB1 was detected in both nuclei and cytoplasm in tumor cells. Additionally, increased plasma HMGB1 levels post-BNCT irradiation were detected even when tumors decreased in size. Collectively, these results indicate that the extracellular HMGB1 release occurs at an early stage and is persistent when tumors are reduced in size; therefore, it is a potential biomarker for evaluating the therapeutic response during BNCT

B cell-derived GABA elicits IL-10⁺ macrophages to limit anti-tumour immunity

GABAを標的とする抗腫瘍免疫機構 --代謝産物を介した免疫細胞間制御の一端を解明--. 京都大学プレスリリース. 2021-11-10.Small, soluble metabolites not only are essential intermediates in intracellular biochemical processes, but can also influence neighbouring cells when released into the extracellular milieu1-3. Here we identify the metabolite and neurotransmitter GABA as a candidate signalling molecule synthesized and secreted by activated B cells and plasma cells. We show that B cell-derived GABA promotes monocyte differentiation into anti-inflammatory macrophages that secrete interleukin-10 and inhibit CD8⁺ T cell killer function. In mice, B cell deficiency or B cell-specific inactivation of the GABA-generating enzyme GAD67 enhances anti-tumour responses. Our study reveals that, in addition to cytokines and membrane proteins, small metabolites derived from B-lineage cells have immunoregulatory functions, which may be pharmaceutical targets allowing fine-tuning of immune responses