69 research outputs found
Insulin receptor cleavage induced by estrogen impairs insulin signaling
Introduction: Soluble insulin receptor (sIR), which is the ectodomain of insulin receptor (IR), is present in human plasma. Plasma sIR levels are positively correlated with blood glucose levels and negatively correlated with insulin sensitivity. An in vitro model of IR cleavage shows that extracellular calpain 2 directly cleaves IR, which generates sIR, and sequential cleavage of the IRβ subunit by γ-secretase impairs insulin signaling in a glucose concentration-dependent manner. Nevertheless, sIR levels vary among subjects with normal glucose levels.
Research design and methods: We examined sIR levels of pregnant women throughout gestation. Using an in vitro model, we also investigated the molecular mechanisms of IR cleavage induced by estradiol.
Results: In pregnant women, sIR levels were positively correlated with estrogen levels and significantly increased at late pregnancy independent of glucose levels. Using an in vitro model, estrogen elicited IR cleavage and impaired cellular insulin signaling. Estradiol-induced IR cleavage was inhibited by targeting of calpain 2 and γ-secretase. Estrogen exerted these biological effects via G protein-coupled estrogen receptor, and its selective ligand upregulated calpain 2 expression and promoted exosome secretion, which significantly increased extracellular calpain 2. Simultaneous stimulation of estrogen and high glucose levels had a synergic effect on IR cleavage. Metformin prevented calpain 2 release in exosomes and restored insulin signaling impaired by estrogen.
Conclusions: Estradiol-induced IR cleavage causes cellular insulin resistance, and its molecular mechanisms are shared with those by high glucose levels. sIR levels at late pregnancy are significantly elevated along with estrogen levels. Therefore, estradiol-induced IR cleavage is preserved in pregnant women and could be part of the etiology of insulin resistance in gestational diabetes mellitus and overt diabetes during pregnancy
Nurture vs. nature in diabetic vasculopathy: roles of advanced glycation endproducts and the receptor for them
金沢大学大学院医学部医学系研究科As is diabetes itself, diabetic vasculopathy is a multifactor disease. Studies conducted in this lab revealed advanced glycation endproducts (AGE) as the major environmental account for vascular cell derangement characteristic of diabetes, and the receptor for AGE (RAGE) as the major genetic factor that responds to them. AGE fractions that caused the vascular derangement were proven to be RAGE ligands. When made diabetic, RAGE-overexpressing transgenic mice exhibited the exacerbation of the indices of nephropathy, and this was prevented by the inhibition of AGE formation. We also created RAGE-deficient mice. They showed marked amelioration of diabetic nephropathy. Extracellular signals and nuclear factors that induce the transcription of human RAGE gene were also identified, which would be regarded as risk factors of diabetic complications. Through an analysis of vascular polysomal poly(A)+ RNA, we came across a novel splice variant coding for a soluble RAGE protein, and named it endogenous secretory RAGE (esRAGE). esRAGE was able to capture AGE ligands and neutralize the AGE action on endothelial cells, suggesting that this variant has a potential to protect blood vessels from diabetes-induced injury. The AGE–RAGE system should thus be regarded as a candidate molecular target for overcoming this life- and quality of life (QOL)-threatening disease
The whole blood transcriptional regulation landscape in 465 COVID-19 infected samples from Japan COVID-19 Task Force
「コロナ制圧タスクフォース」COVID-19患者由来の血液細胞における遺伝子発現の網羅的解析 --重症度に応じた遺伝子発現の変化には、ヒトゲノム配列の個人差が影響する--. 京都大学プレスリリース. 2022-08-23.Coronavirus disease 2019 (COVID-19) is a recently-emerged infectious disease that has caused millions of deaths, where comprehensive understanding of disease mechanisms is still unestablished. In particular, studies of gene expression dynamics and regulation landscape in COVID-19 infected individuals are limited. Here, we report on a thorough analysis of whole blood RNA-seq data from 465 genotyped samples from the Japan COVID-19 Task Force, including 359 severe and 106 non-severe COVID-19 cases. We discover 1169 putative causal expression quantitative trait loci (eQTLs) including 34 possible colocalizations with biobank fine-mapping results of hematopoietic traits in a Japanese population, 1549 putative causal splice QTLs (sQTLs; e.g. two independent sQTLs at TOR1AIP1), as well as biologically interpretable trans-eQTL examples (e.g., REST and STING1), all fine-mapped at single variant resolution. We perform differential gene expression analysis to elucidate 198 genes with increased expression in severe COVID-19 cases and enriched for innate immune-related functions. Finally, we evaluate the limited but non-zero effect of COVID-19 phenotype on eQTL discovery, and highlight the presence of COVID-19 severity-interaction eQTLs (ieQTLs; e.g., CLEC4C and MYBL2). Our study provides a comprehensive catalog of whole blood regulatory variants in Japanese, as well as a reference for transcriptional landscapes in response to COVID-19 infection
DOCK2 is involved in the host genetics and biology of severe COVID-19
「コロナ制圧タスクフォース」COVID-19疾患感受性遺伝子DOCK2の重症化機序を解明 --アジア最大のバイオレポジトリーでCOVID-19の治療標的を発見--. 京都大学プレスリリース. 2022-08-10.Identifying the host genetic factors underlying severe COVID-19 is an emerging challenge. Here we conducted a genome-wide association study (GWAS) involving 2, 393 cases of COVID-19 in a cohort of Japanese individuals collected during the initial waves of the pandemic, with 3, 289 unaffected controls. We identified a variant on chromosome 5 at 5q35 (rs60200309-A), close to the dedicator of cytokinesis 2 gene (DOCK2), which was associated with severe COVID-19 in patients less than 65 years of age. This risk allele was prevalent in East Asian individuals but rare in Europeans, highlighting the value of genome-wide association studies in non-European populations. RNA-sequencing analysis of 473 bulk peripheral blood samples identified decreased expression of DOCK2 associated with the risk allele in these younger patients. DOCK2 expression was suppressed in patients with severe cases of COVID-19. Single-cell RNA-sequencing analysis (n = 61 individuals) identified cell-type-specific downregulation of DOCK2 and a COVID-19-specific decreasing effect of the risk allele on DOCK2 expression in non-classical monocytes. Immunohistochemistry of lung specimens from patients with severe COVID-19 pneumonia showed suppressed DOCK2 expression. Moreover, inhibition of DOCK2 function with CPYPP increased the severity of pneumonia in a Syrian hamster model of SARS-CoV-2 infection, characterized by weight loss, lung oedema, enhanced viral loads, impaired macrophage recruitment and dysregulated type I interferon responses. We conclude that DOCK2 has an important role in the host immune response to SARS-CoV-2 infection and the development of severe COVID-19, and could be further explored as a potential biomarker and/or therapeutic target
自閉症におけるメチルコバラミン療法の予備的検討
我々は13例の自閉症患者でビタミンB_<12>(メチルコバラミン:Me-B_<12>)の治療効果をオープン試験で試みた.Me-B_<12>の治療開始時期は2歳3ヵ月から18歳で,Me-B_<12>を25~30μg/kg/day,6~25ヵ月間投与した.IQ/DQによる評価では,治療前は45±5.3(平均±標準誤差)であったが,治療後は52±6.0と有意な上昇が認められた(p=0.0199).CARS検査(小児自閉症評定尺度)では,治療前は35.9±1.6であったが,治療後は33.0±1.7(p=0.0008)と改善した.自然経過による改善とMe-B_<12>効果を鑑別するため,患者を年齢,知能でそれぞれ2群に分類し検討したところ,思春期群と低IQ群のCARSスコアーが,幼児・早期学童期群,高IQ群と同様に改善した.自閉症児において思春期は一般に症状改善に乏しく,症状の自然改善は高機能自閉症児に見られることから,この結果は, Me-B_<12>効果は自然経過とは異なると考えられた.検討はまだ予備的段階であるが,自閉症においてMe-B_<12>は治療薬として試みる価値があると考えられた.We conducted an open trial on the effect of methylcobalamin (Me-B_<12>) in 13 patients with autism. The patients' ages at the start of treatment ranged from 2 years and 3 months to 18 years. Me-B_<12> was administered at a dosage of 25-30 g/kg/day for 6-25 months. The intelligence and developmental quotient (IQ/DQ) after Me-B_<12>treatment was 52±6.0 (mean ± SE), which was significantly higher than before treatment (45±5.3) (p<0.05). The childhood autism rating scale (CARS) score improved significantly, from 35.9±1.6 before to 33.0±1.7 after treatment (p<0.001). To distinguish the effects of Me-B_<12> from natural developmental factors, the patients were divided into two subgroups, both according to age and according to intelligence. The CARS scores of the teenage and the low-IQ groups improved as much as those of the pre-early school age and the high-IQ groups. As adolescent autism patients usually show a decline in their condition, while some high function autism patients exhibit positive development, the improvement of CARS scores with Me-B_<12> treatment in the teenage and the low-IQ groups suggests that the Me-B_<12> effect is distinct from developmental factors. Although these data are very preliminary, Me-B_<12> is potentially beneficial in autism as an additional or alternative treatment
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