Release of peptide leukotrienes from rat Kupffer cells

Kupffer cells isolated from the normal rat liver were incubated with calcium ionophore A23187, and the levels of peptide leukotrienes (LTC4, LTD4, and LTE4) contained in the culture supernatant were determined by the combined technique of reverse-phase high-performance liquid chromatography and radioimmunoassay. In response to A23187, Kupffer cells released LTC4, LTD4, and LTE4. After 10 min-preincubation of Kupffer cells with AA861, a 5-lipoxygenase inhibitor, the generation of LTC4, LTD4, and LTE4 from A23187-stimulated Kupffer cells was significantly suppressed. Platelet activating factor (PAF), a phospholipid mediator, significantly enhanced the release of LTC4, LTD4, and LTE4 from Kupffer cells stimulated with A23187. These results suggested that Kupffer cells may participate in inflammatory and immunologic events in the liver tissue by the release of peptide leukotrienes.     

High butyric acid amounts induce oxidative stress,alter calcium homeostasis,and cause neurite retraction in nerve growth factor-treated PC12 cells

Butyric acid (BA) is a common secondary metabolite by-product produced by oral pathogenic bacteria and is detected in high amounts in the gingival tissue of patients with periodontal disease. Previous works have demonstrated that BA can cause oxidative stress in various cell types; however, this was never explored using neuronal cells. Here, we exposed nerve growth factor (NGF)-treated PC12 cells to varying BA concentrations (0.5, 1.0, 5.0 mM). We measured total heme, H₂O₂, catalase, and calcium levels through biochemical assays and visualized the neurite outgrowth after BA treatment. Similarly, we determined the effects of other common periodontal short-chain fatty acids (SCFAs) on neurite outgrowth for comparison. We found that high (1.0 and 5.0 mM) BA concentrations induced oxidative stress and altered calcium homeostasis, whereas low (0.5 mM) BA concentration had no significant effect. Moreover, compared to other SCFAs, we established that only BA was able to induce neurite retraction.     

PER1 polymorphism associated with shift work disorder

Sleep and Biological Rhythms - Workers with shift work schedules often experience shift work disorder (SWD). However, all shift workers do not necessarily develop SWD. The aim of this...     

Lead optimization of novel p53-MDM2 interaction inhibitors possessing dihydroimidazothiazole scaffold

With the aim of discovering potent inhibitors of the p53-MDM2 interaction and thus obtaining a potent anticancer drug, we have pursued synthesis and optimization of dihydroimidazothiazole derivatives, which have been discovered via scaffold hopping by mimicing the mode of interaction between MDM2 and Nutlins. Upon the discovery we encountered a problem involving the chemical instability of the scaffold, that is, susceptibility to oxidation which led to imidazothiazole. In order to solve this problem and to obtain further potent compounds, we executed medicinal research and thus furnished the optimal compounds by incorporating the methyl group onto the C-6 position to avoid the oxidation, and by modifying the C-2 moiety of the additional proline motif, which furnished high potency. The incorporation of the pyrrolidine moiety at the C-2 position raised another hydrophobic interaction site with MDM2 protein, which was generated by the induced-fitting observed by co-crystal structure analysis. These optimal molecules showed significant improvement in potency when compared with the early lead (+)-1 or Nutlin-3a.     

Methyl‐isobutyl amiloride reduces brain Lac/NAA,cell death and microglial activation in a perinatal asphyxia model

Na⁺/H⁺ exchanger (NHE) blockade attenuates the detrimental consequences of ischaemia and reperfusion in myocardium and brain in adult and neonatal animal studies. Our aim was to use magnetic resonance spectroscopy (MRS) biomarkers and immunohistochemistry to investigate the cerebral effects of the NHE inhibitor, methyl isobutyl amiloride (MIA) given after severe perinatal asphyxia in the piglet. Eighteen male piglets (aged < 24 h) underwent transient global cerebral hypoxia‐ischaemia and were randomized to (i) saline placebo; or (ii) 3 mg/kg intravenous MIA administered 10 min post‐insult and 8 hourly thereafter. Serial phosphorus‐31 (³¹P) and proton (¹H) MRS data were acquired before, during and up to 48 h after hypoxia‐ischaemia and metabolite‐ratio time‐series Area under the Curve (AUC) calculated. At 48 h, histological and immunohistochemical assessments quantified regional tissue injury. MIA decreased thalamic lactate/N‐acetylaspartate and lactate/creatine AUCs (both p < 0.05) compared with placebo. Correlating with improved cerebral energy metabolism, transferase mediated biotinylated d‐UTP nick end‐labelling (TUNEL) positive cell density was reduced in the MIA group in cerebral cortex, thalamus and white matter (all p < 0.05) and caspase 3 immunoreactive cells were reduced in pyriform cortex and caudate nucleus (both p < 0.05). Microglial activation was reduced in pyriform and midtemporal cortex (both p < 0.05). Treatment with MIA starting 10 min after hypoxia‐ischaemia was neuroprotective in this perinatal asphyxia model.     

Correction to: Field-transcriptome analyses reveal developmental transitions during flowering in cassava (Manihot esculenta Crantz)

Plant Molecular Biology -     

Measles virus infection of SLAM (CD150) knockin mice reproduces tropism and immunosuppression in human infection

The human signaling lymphocyte activation molecule (SLAM, also called CD150), a regulator of antigen-driven T-cell responses and macrophage functions, acts as a cellular receptor for measles virus (MV), and its V domain is necessary and sufficient for receptor function. We report here the generation of SLAM knockin mice in which the V domain of mouse SLAM was replaced by that of human SLAM. The chimeric SLAM had an expected distribution and normal function in the knockin mice. Splenocytes from the SLAM knockin mice permitted the in vitro growth of a virulent MV strain but not that of the Edmonston vaccine strain. Unlike in vitro infection, MV could grow only in SLAM knockin mice that also lacked the type I interferon receptor (IFNAR). After intraperitoneal or intranasal inoculation, MV was detected in the spleen and lymph nodes throughout the body but not in the thymus. Notably, the virus appeared first in the mediastinal lymph node after intranasal inoculation. Splenocytes from MV-infected IFNAR(-/-) SLAM knockin mice showed suppression of proliferative responses to concanavalin A. Thus, MV infection of SLAM knockin mice reproduces lymphotropism and immunosuppression in human infection, serving as a useful small animal model for measles.     

DNA polymerase theta (POLQ) can extend from mismatches and from bases opposite a (6-4) photoproduct

DNA polymerase theta (pol theta) is a nuclear A-family DNA polymerase encoded by the POLQ gene in vertebrate cells. The biochemical properties of pol theta and of Polq-defective mice have suggested that pol theta participates in DNA damage tolerance. For example, pol theta was previously found to be proficient not only in incorporation of a nucleotide opposite a thymine glycol or an abasic site, but also extends a polynucleotide chain efficiently from the base opposite the lesion. We carried out experiments to determine whether this ability to extend from non-standard termini is a more general property of the enzyme. Pol theta extended relatively efficiently from matched termini as well as termini with A:G, A:T and A:C mismatches, with less descrimination than a well-studied A-family DNA polymerase, exonuclease-free pol I from E. coli. Although pol theta was unable to, by itself, bypass a cyclobutane pyrimidine dimer or a (6-4) photoproduct, it could perform some extension from primers with bases placed across from these lesions. When pol theta was combined with DNA polymerase iota, an enzyme that can insert a base opposite a UV-induced (6-4) photoproduct, complete bypass of a (6-4) photoproduct was possible. These data show that in addition to its ability to insert nucleotides opposite some DNA lesions, pol theta is proficient at extension of unpaired termini. These results show the potential of pol theta to act as an extender after incorporation of nucleotides by other DNA polymerases, and aid in understanding the role of pol theta in somatic mutagenesis and genome instability.