Glutaredoxin, Grx, is a small protein containing an active site cysteine pair and was discovered in 1976 by Arne Holmgren. The Grx system, comprised of Grx, glutathione, glutathione reductase, and ...NADPH, was first described as an electron donor for Ribonucleotide Reductase but, from the first discovery in E.coli, the Grx family has impressively grown, particularly in the last two decades. Several isoforms have been described in different organisms (from bacteria to humans) and with different functions.
The unique characteristic of Grxs is their ability to catalyse glutathione-dependent redox regulation via glutathionylation, the conjugation of glutathione to a substrate, and its reverse reaction, deglutathionylation. Grxs have also recently been enrolled in iron sulphur cluster formation. These functions have been implied in various physiological and pathological conditions, from immune defense to neurodegeneration and cancer development thus making Grx a possible drug target.
This review aims to give an overview on Grxs, starting by a phylogenetic analysis of vertebrate Grxs, followed by an analysis of the mechanisms of action, the specific characteristics of the different human isoforms and a discussion on aspects related to human physiology and diseases.
The combination of ascorbate and menadione (VC:VK3 = 100:1) is an investigational treatment for cancer under clinical trials. Dehydroascorbic acid (DHA), the oxidized form of ascorbate, can be taken ...up by cells via glucose transporters, over-expressed in many cancer cells. It has been known that the combination of VC/VK3 kills cancer cells by inducing hydrogen peroxide (H2O2) via a redox cycling reaction. However, the mechanism has not been fully understood yet. Intracellularly, DHA is reduced to ascorbate by NADPH via GSH and glutaredoxin as well as by thioredoxin (Trx) and the selenoenzyme thioredoxin reductase (TrxR). These two systems are also critical as electron donors for ribonucleotide reductase (RNR), which produces deoxyribonucleotides de novo for DNA replication and DNA repair and is highly expressed in tumor cells. We found that RNR was highly sensitive to VC/VK3 in vitro with similar effects as observed with H2O2. In cancer cells, VC/VK3 inhibited RNR mainly by targeting its R2 subunit. More importantly, both the Trx and GSH systems were oxidized by the combination, which resulted in the loss of GSH, increased protein glutathionylation, and highly oxidized Trx1. The mechanism of cell death induced by VC/VK3 was also elucidated. We found that VC/VK3 inhibited glutathione peroxidase activity and led to an elevated level of lipid peroxidation, which triggered apoptosis-inducing factor (AIF) mediated cell death pathway. Therefore, the combination not only induced replicative stress by inhibiting RNR, but also oxidative stress by targeting anti-oxidant systems and triggered AIF-mediated cancer cell death.
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•Cancer cells usually have higher level of ROS, thus are more sensitive to ROS challenge.•Ascorbate (VC) and menadione (VK3) in combination (VC/VK3) generated ROS via a redox cycling.•Oxidative stress was induced by impairing Trx system and GSH system.•Replicative stress was induced by disturbing DNA synthesis through RNR.•The AIF cell death pathway was initiated by VC/VK3.
A lattice Boltzmann method for two-phase immiscible fluids with large density differences is proposed. The difficulty in the treatment of large density difference is resolved by using the projection ...method. The method can be applied to simulate two-phase fluid flows with the density ratio up to 1000. To show the validity of the method, we apply the method to the simulations of capillary waves, binary droplet collisions, and bubble flows. In capillary waves, the angular frequencies of the oscillation of an ellipsoidal droplet are obtained in good agreement with theoretical ones. In the simulations of binary droplet collisions, coalescence collision and two different types of separating collisions, namely reflexive and stretching separations, can be simulated, and the boundaries of the three types of collisions are in good agreement with an available theoretical prediction. In the bubble flows, the effect of mobility on the coalescence of two rising bubbles is investigated. The behavior of many bubbles in a square duct is also simulated.
A majority of children with Type 1 diabetes in Japan are registered with the government-subsidized Specified Pediatric Chronic Disease Treatment Research Projects (SPCDTRP). In this study, the ...incidence and prevalence of childhood-onset (< 15 years) Type 1 diabetes in Japan were estimated by drawing on SPCDTRP data.
Data available for 2005-2012 from the SPCDTRP and Statistics Bureau, Ministry of Internal Affairs and Communications were used to estimate the incidence of Type 1 diabetes for 2005-2010, adjusted to cover those registered within 3 years of disease onset and stratified by sex, age at onset and period of onset.
The incidence of Type 1 diabetes for 2005-2010 was 2.25/100,000 persons 95% confidence intervals (95% CI), 2.14-2.36 (boys: 1.91, 95% CI, 1.83-1.98; girls: 2.52, 95% CI, 2.34-2.69), with that for the age brackets 0-4, 5-9 and 10-14 years being 1.48 (95% CI, 1.29-1.66), 2.27 (95% CI, 2.08-2.47) and 3.00 (95% CI, 2.74-3.25), respectively. The onset of disease was shown to peak at age 13 among boys (3.28, 95% CI, 3.02-3.55) and at age 10 among girls (3.28, 95% CI, 3.02-3.55). The peak periods of disease onset were April/May and December. The number of children aged < 15 years with Type 1 diabetes for 2005-2012 was estimated to be 2326 (95% CI, 2202-2450) with the prevalence estimated as 13.53/100,000 persons (95% CI, 12.63-14.43).
Study findings demonstrated no increase in the incidence of Type 1 diabetes, although suggesting, in agreement with earlier reports, that the onset of disease peaks in adolescence with a female predominance. In addition, the incidence of childhood-onset diabetes exhibited an annual bimodal pattern in this study.
The Thermodynamics of Advanced Fuels – International Database (TAF-ID) was developed using the Calphad method to provide a computational tool to perform thermodynamic calculations on nuclear fuel ...materials under normal and off-normal conditions. Different kinds of fuels are considered: oxide, metallic, carbide and nitride fuels. Many fission products are introduced as well as structural materials (e.g., zirconium, steel, concrete, SiC) and absorbers (e.g., B4C), in order to investigate the thermochemistry of irradiated fuels and to predict their chemical interaction with the surrounding materials. The approach to develop the database and the models implemented in the database are described. Examples of models for key chemical systems are presented. Finally, a few examples of application calculations on severe accidents with UO2 fuels, irradiated fuel chemistry of MOX and metallic fuels and metallic fuel/cladding interaction show how this tool can be used. To validate the database, the calculations are compared to the available experimental data. A good agreement is obtained which gives confidence in the maturity degree and quality of the TAF-ID database. The working version is only accessible to the participants of the TAF-ID project (Canada, France, Japan, the Netherlands, Republic of Korea, United Kingdom, USA). A public version is accessible by all the NEA countries. The current version contains models on the Am–Fe, Am–Np, Am-O-Pu, Am–U, Am–Zr, C–O–U-Pu, Cr–U, Np–U, Np–Zr, O–U–Zr, Re–U, Ru–U, Si–U, Ti–U, U-Pu-Zr, U–W systems. It is progressively extended with our published assessments. Information on how to join the project is available on the website: https://www.oecd-nea.org/science/taf-id/.
•The TAF-ID international thermodynamic database is a computational tool for nuclear fuel applications.•Key systems for nuclear fuels are modelled using the Calphad method.•Fission product chemistry of irradiated fuels is predicted.•Chemical interaction with structural materials can be predicted under normal and severe accident conditions.•Coupling with kinetics, phase-field, Fuel Performance Code is being performed.
Although complex chromosomal rearrangements were thought to reflect the accumulation of DNA damage over time, recent studies have shown that such rearrangements frequently arise from ‘all‐at‐once’ ...catastrophic cellular events. These events, designated chromothripsis, chromoanasynthesis, and chromoanagenesis, were first documented in the cancer genome and subsequently observed in the germline. These events likely result from micronucleus‐mediated chromosomal shattering and subsequent random reassembly of DNA fragments, although several other mechanisms have also been proposed. Typically, only one or a few chromosomes of paternal origin are affected per event. These events can produce intrachromosomal deletions, duplications, inversions, and translocations, as well as interchromosomal translocations. Germline complex rearrangements of autosomes often result in developmental delay and dysmorphic features, whereas X chromosomal rearrangements are usually associated with relatively mild clinical manifestations. The concept of these catastrophic events provides novel insights into the etiology of human genomic disorders. This review introduces the molecular characteristics and phenotypic outcomes of catastrophic cellular events in the germline.
Do monosomy rescue (MR) and trisomy rescue (TR) in preimplantation human embryos affect other developmental processes, such as X-chromosome inactivation (XCI)?
Aneuploid rescue precedes XCI and ...increases the incidence of XCI skewness by reducing the size of the embryonic progenitor cell pools.
More than half of preimplantation human embryos harbor aneuploid cells, some of which can be spontaneously corrected through MR or TR. XCI in females is an indispensable process, which is predicted to start at the early-blastocyst phase.
We examined the frequency of XCI skewness in young females who carried full uniparental disomy (UPD) resulting from MR or TR/gamete complementation (GC). The results were statistically analyzed using a theoretical model in which XCI involves various numbers of embryonic progenitor cells.
We studied 39 children and young adults ascertained by imprinting disorders. XCI ratios were determined by DNA methylation analysis of a polymorphic locus in the androgen receptor gene. We used Bayesian approach to assess the probability of the occurrence of extreme XCI skewness in the MR and TR/GC groups using a theoretical model of 1-12 cell pools.
A total of 12 of 39 individuals (31%) showed skewed XCI. Extreme skewness was observed in 3 of 15 MR cases (20%) and 1 of 24 TR/GC cases (4.2%). Statistical analysis indicated that XCI in the MR group was likely to have occurred when the blastocyst contained three or four euploid embryonic progenitor cells. The estimated size of the embryonic progenitor cell pools was approximately one-third or one-fourth of the predicted size of normal embryos. The TR/GC group likely had a larger pool size at the onset of XCI, although the results remained inconclusive.
This is an observational study and needs to be validated by experimental analyses.
This study provides evidence that the onset of XCI is determined by an intrinsic clock, irrespectively of the number of embryonic progenitor cells. Our findings can also be applied to individuals without UPD or imprinting disorders. This study provides a clue to understand chromosomal and cellular dynamics in the first few days of human development, their effects on XCI skewing and the possible implications for the expression of X-linked diseases in females.
This study was supported by the Grants-in-aid for Scientific Research on Innovative Areas (17H06428) and for Scientific Research (B) (17H03616) from Japan Society for the Promotion of Science (JSPS), and grants from Japan Agency for Medical Research and Development (AMED) (18ek0109266h0002 and 18ek0109278h0002), National Center for Child Health and Development and Takeda Science Foundation. The authors declare no conflict of interest.
Not applicable.
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