Proc Natl Acad Sci U S A
November 2024
Neutrophil extracellular traps (NETs), essential for controlling infections, can induce various pathologies when dysregulated. Known triggers for infection-independent NETs release exist, yet a comprehensive understanding of the conditions prompting such responses is lacking. In this study, we identify hyponatremia as an independent inducer of NETs release, a common clinical condition that disrupts sodium/calcium exchange within neutrophils.
View Article and Find Full Text PDFRAF kinases are key components of the RAS-MAPK signaling pathway, which drives cell growth and is frequently overactivated in cancer. Upstream signaling activates the small GTPase RAS, which recruits RAF to the cell membrane, driving a transition of the latter from an auto-inhibited monomeric conformation to an active dimer. Despite recent progress, mechanistic details underlying RAF activation remain unclear, particularly the role of RAS and the membrane in mediating this conformational rearrangement of RAF together with 14-3-3 to permit RAF kinase domain dimerization.
View Article and Find Full Text PDFThe remarkable performance of ChatGPT, launched in November 2022, has significantly impacted the field of natural language processing, inspiring the application of large language models as supportive tools in clinical practice and research worldwide. Although GPT-3.5 recently scored high on the United States Medical Licensing Examination, its performance on medical licensing examinations of other nations, especially non-English speaking nations, has not been sufficiently evaluated.
View Article and Find Full Text PDFBackground: The coronavirus disease 2019 (COVID-19) pandemic impacted various parts of society, including Japanese children with allergies.
Objective: This study investigated risk factors for pediatric allergic diseases associated with the state of emergency owing to the COVID-19 pandemic in Japan, including during school closures.
Methods: Parents of pediatric patients (0-15 years) with allergies were enrolled and queried regarding the impact of school closure on pediatric allergies compared to that before the COVID-19 pandemic.
DiRAS3, also called ARHI, is a RAS (sub)family small GTPase protein that shares 50-60% sequence identity with H-, K-, and N-RAS, with substitutions in key conserved G-box motifs and a unique 34 amino acid extension at its N-terminus. Unlike the RAS proto-oncogenes, DiRAS3 exhibits tumor suppressor properties. DiRAS3 function has been studied through genetics and cell biology, but there has been a lack of understanding of the biochemical and biophysical properties of the protein, likely due to its instability and poor solubility.
View Article and Find Full Text PDFTo increase the prediction accuracy of positive oral food challenge (OFC) outcomes during stepwise slow oral immunotherapy (SS-OIT) in children with a hen's egg (HE) allergy, we evaluated the predictive value of the combination of antigen-specific IgE (sIgE) with antigen binding avidity and sIgG4 values. Sixty-three children with HE allergy undergoing SS-OIT were subjected to repeated OFCs with HE. We measured the ovomucoid (OVM)-sIgE by ImmunoCAP or densely carboxylated protein (DCP) microarray, sIgG4 by DCP microarray, and the binding avidity of OVM-sIgE defined as the level of 1/IC (nM) measured by competitive binding inhibition assays.
View Article and Find Full Text PDFLarge amounts of radiocesium were released into marine environments following the Fukushima Daiichi Nuclear Power Plant accident in March 2011. Released radiocesium influenced not only marine environment but also marine biota in Fukushima. Since marine biota as fisheries products is important for Japanese market, it is important to assess the distribution of radiocesium in coastal environment off Fukushima for safety concerns of radioactive contamination.
View Article and Find Full Text PDFKRAS forms transient dimers and higher-order multimers (nanoclusters) on the plasma membrane, which drive MAPK signaling and cell proliferation. KRAS is a frequently mutated oncogene, and while it is well known that the most prevalent mutation, G12D, impairs GTP hydrolysis, thereby increasing KRAS activation, G12D has also been shown to enhance nanoclustering. Elucidating structures of dynamic KRAS assemblies on a membrane has been challenging, thus we have refined our NMR approach that uses nanodiscs to study KRAS associated with membranes.
View Article and Find Full Text PDFRare coding variants of the microglial triggering receptor expressed on myeloid cells 2 (TREM2) confer an increased risk for Alzheimer's disease (AD) characterized by the progressive accumulation of aggregated forms of amyloid β peptides (Aβ). Aβ peptides are generated by proteolytic processing of the amyloid precursor protein (APP). Heterogeneity in proteolytic cleavages and additional post-translational modifications result in the production of several distinct Aβ variants that could differ in their aggregation behavior and toxic properties.
View Article and Find Full Text PDFBackground: Oral care using chlorhexidine has been considered useful in reducing the incidence of ventilator-associated pneumonia (VAP) in adult patients. However, no study has proved the effect of oral care in reducing the incidence of VAP in preterm infants.
Objectives: To investigate the efficacy of oral care using a sponge brush moistened with sterile water in reducing the bacterial load in the oral cavity and the incidence of early-onset VAP in preterm infants METHODS: The bacterial number in the oral cavity was evaluated on-site with the dielectrophoretic impedance measurement system.
In addition to its function of innate immunity against invading pathogens, neutrophil extracellular traps (NETs) promote thrombosis, autoimmune disease, and cancer metastasis; therefore, unnecessary exposure to the triggers of infection-independent NET generation should be avoided. We herein show that inhibition of forward-mode Na/Ca exchange by amiloride analogs, 5-(N-ethyl-N-isopropyl)amiloride (EIPA) and 5-(N-Methyl-N-isobutyl)amiloride (MIA), triggers NETotic cell death independently of infectious stimuli. Isolated human neutrophils treated with EIPA and MIA undergo NETotic cell death by an increase of intracellular Ca following activation of NADPH oxidase and the resultant upregulation of intracellular ROS.
View Article and Find Full Text PDFTREM2 is a pattern recognition receptor, expressed on microglia and myeloid cells, detecting lipids and Aβ and inducing an innate immune response. Missense mutations (e.g.
View Article and Find Full Text PDFThe ongoing COVID-19 pandemic has highlighted the immediate need for the development of antiviral therapeutics targeting different stages of the SARS-CoV-2 life cycle. We developed a bioluminescence-based bioreporter to interrogate the interaction between the SARS-CoV-2 viral spike (S) protein and its host entry receptor, angiotensin-converting enzyme 2 (ACE2). The bioreporter assay is based on a nanoluciferase complementation reporter, composed of two subunits, large BiT and small BiT, fused to the S receptor-binding domain (RBD) of the SARS-CoV-2 S protein and ACE2 ectodomain, respectively.
View Article and Find Full Text PDFMutations in RAS oncogenes occur in ~ 30% of human cancers, with KRAS being the most frequently altered isoform. RAS proteins comprise a conserved GTPase domain and a C-terminal lipid-modified tail that is unique to each isoform. The GTPase domain is a 'switch' that regulates multiple signaling cascades that drive cell growth and proliferation when activated by binding GTP, and the signal is terminated by GTP hydrolysis.
View Article and Find Full Text PDFCalmodulin (CaM) is a Ca-sensor that regulates a wide variety of target proteins, many of which interact through short basic helical motifs bearing two hydrophobic 'anchor' residues. CaM comprises two globular lobes, each containing a pair of EF-hand Ca-binding motifs that form a Ca-induced hydrophobic pocket that binds an anchor residue. A central flexible linker allows CaM to accommodate diverse targets.
View Article and Find Full Text PDFKRAS4b is a small guanosine triphosphatase (GTPase) protein that regulates several signal transduction pathways that underlie cell proliferation, differentiation, and survival. KRAS4b function requires prenylation of its C terminus and recruitment to the plasma membrane, where KRAS4b activates effector proteins including the RAF family of kinases. The Ca-sensing protein calmodulin (CaM) has been suggested to regulate the localization of KRAS4b through direct, Ca-dependent interaction, but how CaM and KRAS4b functionally interact is controversial.
View Article and Find Full Text PDFKRAS homo-dimerization has been implicated in the activation of RAF kinases, however, the mechanism and structural basis remain elusive. We developed a system to study KRAS dimerization on nanodiscs using paramagnetic relaxation enhancement (PRE) NMR spectroscopy, and determined distinct structures of membrane-anchored KRAS dimers in the active GTP- and inactive GDP-loaded states. Both dimerize through an α4-α5 interface, but the relative orientation of the protomers and their contacts differ substantially.
View Article and Find Full Text PDFStore operated calcium (Ca) entry (SOCE) is the process whereby endoplasmic reticulum (ER) Ca store depletion causes Orai1-composed Ca channels on the plasma membrane (PM) to open, mediating a rise in cytosolic Ca levels. Stromal interaction molecules (STIMs) are the proteins that directly sense ER Ca content and gate Orai1 channels due to store depletion. The trigger for STIM activation is Ca unbinding from the ER lumen-oriented domains, which consist of a nonconserved amino (N) terminal region and EF-hand and sterile α motif (SAM) domains (EF-SAM), highly conserved from humans to Caenorhabditis elegans.
View Article and Find Full Text PDFPrevious studies have highlighted the importance of confirming the position of an umbilical venous catheter (UVC) tip by an ultrasound (US) examination. However, methods for preventing insertion into the portal circulation under US guidance have not yet been established. We report 15 cases in which a UVC was successfully passed through the ductus venosus by compressing the upper abdomen near the portal sinus of the liver to align the umbilical vein and ductus venosus under US guidance.
View Article and Find Full Text PDFNeutrophil extracellular traps (NETs) promote cancer metastasis in preclinical models following massive exogenous inflammatory stimuli. It remains unknown whether cancer hosts under physiologic conditions experience NETosis and consequent metastasis. Here we show that plasma redox imbalance caused by albumin oxidation promotes inflammation-independent NETosis.
View Article and Find Full Text PDFBackground: Blood gas analyses are usually required more frequently in preterm neonates than in term neonates. If total bilirubin (TB) levels in whole blood measured using a blood gas analyzer are reliable, blood sampling for total serum bilirubin (TSB) levels alone can be reduced in preterm neonates. We investigated the reliability of measuring TB levels in whole blood from preterm neonates using the latest generation blood gas analyzer.
View Article and Find Full Text PDFBackground: We tested whether direct transcutaneous bilirubin (TcB) measurement from an area unexposed to phototherapy is reliable for estimation of total serum bilirubin (TSB) in neonates during phototherapy and whether it contributes to reduction in TSB blood sampling in phototherapy decision making.
Methods: This was a retrospective observational study of term neonates who received phototherapy in the mother's room. TSB and TcB from the neonate's sternum were measured before and during phototherapy and compared using linear regression analysis and Bland-Altman plot, respectively.
All eukaryotic cells have adapted the use of the calcium ion (Ca) as a universal signaling element through the evolution of a toolkit of Ca sensor, buffer and effector proteins. Among these toolkit components, integral and peripheral proteins decorate biomembranes and coordinate the movement of Ca between compartments, sense these concentration changes and elicit physiological signals. These changes in compartmentalized Ca levels are not mutually exclusive as signals propagate between compartments.
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