In silico and in vitro investigations on the protein–protein interactions of glutathione S-transferases with mitogen-activated protein kinase 8 and apoptosis signal-regulating kinase 1

Cytosolic glutathione S-transferase (GST) enzymes participate in several cellular processes in addition to facilitating glutathione conjugation reactions that eliminate endogenous and exogenous toxic compounds, especially electrophiles. GSTs are thought to interact with various kinases, resulting in the modulation of apoptotic processes and cellular proliferation. The present research used a combination of in silico and in vitro studies to investigate protein–protein interactions between the seven most abundant cytosolic GSTs—GST alpha-1 (GST-A1), GST alpha-2 (GST-A2), GST mu-1 (GST-M1), GST mu-2 (GST-M2), GST mu-5 (GST-M5), GST theta-1 (GST-T1) and GST pi-1 (GST-P1)—and Mitogen-activated protein kinase 8 (MAPK8) and Apoptosis signal-regulating kinase 1 (ASK1). MAPK8 and ASK1 were chosen as this study’s protein interaction partners because of their predominant role in electrophile or cytokine-induced stress-mediated apoptosis, inflammation and fibrosis. The highest degree of sequence homology or sequence similarity was observed in two GST subgroups: the GST-A1, GST-A2 and GST-P1 isoforms constituted subgroup1; the GST-M1, GST-M2 and GST-M5 isoforms constituted subgroup 2. The GST-T1 isoform diverged from these isoforms. In silico investigations revealed that GST-M1 showed a significantly higher binding affinity to MAPK8, and its complex was more structurally stable than the other isoforms, in the order GST-M1 > GST-M5 > GST-P1 > GST-A2 > GST-A1 > GST-M2 > GST-T1. Similarly, GST-A1, GST-P1 and GST-T1 actively interacted with ASK1, and their structural stability was also better, in the order GST-T1 > GST-A1 > GST-P1 > GST-A2 > GST-M5 > GST-M1 > GST-M2. To validate in silico results, we performed in vitro crosslinking and mass spectroscopy experiments. Results indicated that GST-M1 interacted with GST-T1 to form heterodimers and confirmed the predicted interaction between GST-M1 and MAPK8. Communicated by Ramaswamy H. Sarma.publishersversioninpres

Identification of putative substrates and inhibitors for Glutathione S-transferases using computational methods

Glutathione S-transferases (GSTs) comprise a family of enzymes that utilizes glutathione (GSH) in many enzymatic reactions that involved in transformation of several compounds including therapeutic drug molecules and carcinogens. In addition, GSTs influence cellular survival and proliferation, by repressing apoptosis signal-regulating kinase 1 (ASK1) thus affecting the activation of p38 mitogen-activated protein kinase (MAPK) and c-Jun N-terminal kinase (JNK) in response to various intra and extracellular stresses. Molecules inhibiting the function of GSTs received attention as an adjuvant therapy to the highly toxic electrophilic agents to avoid usage of high doses and toxicity for better outcomes. There is no detailed in silico analysis exists in literature to describe the binding patterns of known inhibitors to all GST isoforms. This study is aimed at providing details of binding patterns of known and putative substrates (Busulfan, Treosulfan, SS-EBDM, SS-DEB), inhibitors (Ethacrynic acid, Sulfolane and Curcumin) with predominately-expressed seven isoforms of GST (Alpha1, Alpha2, Pi1, Mu1, Mu2, Mu5 and Theta1). In silico methodology include six steps namely (a) Retrieval of three-dimensional structure of GSTs and Ligand molecules from RCSB-PDB and NCBI-PubChem databases, (b) Protein and Ligand preparation using Auto Dock Tools (ADT), (c) Receptor grid preparation based on known binding site (Direct docking protocol) of GSTs using AutoDock/Vina plugin in PyMOL, (d) Preparation of Auto Dock Vina configuration file, (e) Running of docking calculation using Auto Dock Vina and (f) Analysis of docking results using ADT, PyMOL and LigPlus programs. Molecular docking studies of substrates/inhibitors are performed with both Apo and GSH bounded forms of GSTs. Structural parameters such as estimated free energy of binding (ΔH), estimated inhibition constant (Ki), binding orientation, intermolecular interactions were noted for all the docking interaction models. Then the parameters were compared against each substrate or inhibitor for the affinity towards a selective GST isoform. Out of the three putative or known inhibitors screened, Curcumin showed a significant high binding affinity towards all the classes of GSTs, particularly GST Alpha1 (ΔH: -9.7 kcal/mol and Ki: 0.08 µM). Ethacrynic acid also showed better binding affinity towards GST Alpha1 (ΔH: -7.6 kcal/mol and Ki: 2.7 uM). Sulfolane did not exhibited a stronger affinity towards all the seven GST isoforms. Busulfan and Treosulfan exhibited a reasonable binding affinity towards GST Alpha1 (ΔH: -5.2 and -5.3 kcal/mol) and weakened affinity for the remaining six GST isoforms. Thus, treosulfan could be a possible substrate for GST Alpha1. Manual inspection of three-dimensional structures of the docking complexes revealed that binding-sites for inhibitor and substrate are different. In an on-going study, we are evaluating the inhibitory potential of Curcumin and Ethacrynic acid against GSTs in in vitro studies. The detailed description of the binding interactions may be useful to screen new putative GST substrates and inhibitors. Presence or absence of variants in these binding pockets also can define the amount of inhibitor required and the affinity and potency of an inhibitor and or substrate. This poster is presented at " ESPT 2017 in Catania, Italy from Oct 4th-7th 2017

Cohort-based association study of germline genetic variants with acute and chronic health complications of childhood cancer and its treatment: Genetic Risks for Childhood Cancer Complications Switzerland (GECCOS) study protocol

INTRODUCTION: Childhood cancer and its treatment may lead to various health complications. Related impairment in quality of life, excess in deaths and accumulated healthcare costs are relevant. Genetic variations are suggested to contribute to the wide inter-individual variability of complications but have been used only rarely to risk-stratify treatment and follow-up care. This study aims to identify germline genetic variants associated with acute and late complications of childhood cancer. METHODS AND ANALYSIS: The Genetic Risks for Childhood Cancer Complications Switzerland (GECCOS) study is a nationwide cohort study. Eligible are patients and survivors who were diagnosed with childhood cancers or Langerhans cell histiocytosis before age 21 years, were registered in the Swiss Childhood Cancer Registry (SCCR) since 1976 and have consented to the Paediatric Biobank for Research in Haematology and Oncology, Geneva, host of the national Germline DNA Biobank Switzerland for Childhood Cancer and Blood Disorders (BISKIDS).GECCOS uses demographic and clinical data from the SCCR and the associated Swiss Childhood Cancer Survivor Study. Clinical outcome data consists of organ function testing, health conditions diagnosed by physicians, second primary neoplasms and self-reported information from participants. Germline genetic samples and sequencing data are collected in BISKIDS. We will perform association analyses using primarily whole-exome or whole-genome sequencing to identify genetic variants associated with specified health conditions. We will use clustering and machine-learning techniques and assess multiple health conditions in different models. DISCUSSION: GECCOS will improve knowledge of germline genetic variants associated with childhood cancer-associated health conditions and help to further individualise cancer treatment and follow-up care, potentially resulting in improved efficacy and reduced side effects. ETHICS AND DISSEMINATION: The Geneva Cantonal Commission for Research Ethics has approved the GECCOS study.Research findings will be disseminated through national and international conferences, publications in peer-reviewed journals and in lay language online

Correction to: GSTM1 and GSTT1 double null genotypes determining cell fate and proliferation as potential risk factors of relapse in children with hematological malignancies after hematopoietic stem cell transplantation

Transplantation and immunomodulatio

Organization-wide adoption of computerized provider order entry systems: a study based on diffusion of innovations theory

Background: Computerized provider order entry (CPOE) systems have been introduced to reduce medication errors, increase safety, improve work-flow efficiency, and increase medical service quality at the moment of prescription. Making the impact of CPOE systems more observable may facilitate their adoption by users. We set out to examine factors associated with the adoption of a CPOE system for inter-organizational and intra-organizational care. Methods: The diffusion of innovation theory was used to understand physicians and nurses attitudes and thoughts about implementation and use of the CPOE system. Two online survey questionnaires were distributed to all physicians and nurses using a CPOE system in county-wide healthcare organizations. The number of complete questionnaires analyzed was 134 from 200 nurses (67.0%) and 176 from 741 physicians (23.8%). Data were analyzed using descriptive-analytical statistical methods. Results: More nurses (56.7%) than physicians (31.3%) stated that the CPOE system introduction had worked well in their clinical setting (P andlt; 0.001). Similarly, more physicians (73.9%) than nurses (50.7%) reported that they found the system not adapted to their specific professional practice (P = andlt; 0.001). Also more physicians (25.0%) than nurses (13.4%) stated that they did want to return to the previous system (P = 0.041). We found that in particular the received relative advantages of the CPOE system were estimated to be significantly (P andlt; 0.001) higher among nurses (39.6%) than physicians (16.5%). However, physicians agreements with the compatibility of the CPOE and with its complexity were significantly higher than the nurses (P andlt; 0.001). Conclusions: Qualifications for CPOE adoption as defined by three attributes of diffusion of innovation theory were not satisfied in the study setting. CPOE systems are introduced as a response to the present limitations in paper-based systems. In consequence, user expectations are often high on their relative advantages as well as on a low level of complexity. Building CPOE systems therefore requires designs that can provide rather important additional advantages, e. g. by preventing prescription errors and ultimately improving patient safety and safety of clinical work. The decision-making process leading to the implementation and use of CPOE systems in healthcare therefore has to be improved. As any change in health service settings usually faces resistance, we emphasize that CPOE system designers and healthcare decision-makers should continually collect users feedback about the systems, while not forgetting that it also is necessary to inform the users about the potential benefits involved.Original Publication:Bahlol Rahimi, Toomas Timpka, Vivian Vimarlund, Srinivas Uppugunduri and Mikael Svensson, Organization-wide adoption of computerized provider order entry systems: a study based on diffusion of innovations theory, 2009, BMC MEDICAL INFORMATICS AND DECISION MAKING, (9), 52, .http://dx.doi.org/10.1186/1472-6947-9-52Licensee: BioMed Centralhttp://www.biomedcentral.com/. On the day of the defence date the original title of this article was "Adoption of computerized provider order entry systems: An organization-wide study based on diffusion of innovations theory"

Association study of candidate DNA-repair gene variants and acute graft versus host disease in pediatric patients receiving allogeneic hematopoietic stem-cell transplantation

Acute Graft versus Host Disease (aGvHD) grades 2-4 occurs in 15-60% of pediatric patients undergoing allogeneic haematopoietic stem-cell transplantation (allo-HSCT). The collateral damage to normal tissue by conditioning regimens administered prior to allo-HSCT serve as an initial trigger for aGvHD. DNA-repair mechanisms may play an important role in mitigating this initial damage, and so the variants in corresponding DNA-repair protein-coding genes via affecting their quantity and/or function. We explored 51 variants within 17 DNA-repair genes for their association with aGvHD grades 2-4 in 60 pediatric patients. The cumulative incidence of aGvHD 2-4 was 12% (n = 7) in the exploratory cohort. MGMT rs10764881 (G>A) and EXO rs9350 (c.2270C>T) variants were associated with aGvHD 2-4 [Odds ratios = 14.8 (0 events out of 40 in rs10764881 GG group) and 11.5 (95% CI: 2.3-191.8), respectively, multiple testing corrected p A) remained significant (adjusted HR = 2.05 [95% CI: 1.06-3.94]; p = 0.03) in the presence of other clinical risk factors. Higher MGMT expression was seen in GG carriers for rs10764881 and was associated with higher IC50 of Busulfan in lymphoblastoid cells. MGMT rs10764881 carrier status could predict aGvHD occurrence in pediatric patients undergoing allo-HSCT.Transplantation and immunomodulatio

Diagnosis and severity criteria for sinusoidal obstruction syndrome/veno-occlusive disease in pediatric patients : a new classification from the European society for blood and marrow transplantation

The advances in hematopoietic cell transplantation (HCT) over the last decade have led to a transplant-related mortality below 15%. Hepatic sinusoidal obstruction syndrome/veno-occlusive disease (SOS/VOD) is a life-threatening complication of HCT that belongs to a group of diseases increasingly identified as transplant-related, systemic endothelial diseases. In most cases, SOS/VOD resolves within weeks; however, severe SOS/VOD results in multi-organ dysfunction/failure with a mortality rate > 80%. A timely diagnosis of SOS/VOD is of critical importance, given the availability of therapeutic options with favorable tolerability. Current diagnostic criteria are used for adults and children. However, over the last decade it has become clear that SOS/VOD is significantly different between the age groups in terms of incidence, genetic predisposition, clinical presentation, prevention, treatment and outcome. Improved understanding of SOS/VOD and the availability of effective treatment questions the use of the Baltimore and Seattle criteria for diagnosing SOS/VOD in children. The aim of this position paper is to propose new diagnostic and severity criteria for SOS/VOD in children on behalf of the European Society for Blood and Marrow Transplantation.Peer reviewe

Enzyme Kinetics

Enzyme Kinetics Course Presentatio

Quantification of sulfolane, a metabolite of busulfan in plasma by gas chromatography and tandem mass spectrometry: a new method for evaluating the role of sulfolane and metabolic fate of busulfan

We developed a novel method for determination of sulfolane along with busulfan in plasma of patients receiving busulfan Method was validated with acceptable levels of trueness and precision Sulfolane is detectable at 4 h after the end of 1st dose infusion, and higher levels were observed after the 9th dose infusion of busulfan Understanding kinetics of sulfolane and understanding the role of sulfolane in clinical outcomes and toxicity of busulfan treatment is possible with this metho