59 research outputs found
Gasdermin D Hypermethylation Inhibits Pyroptosis And LPS-Induced IL-1β Release From NK92 Cells
INTRODUCTION: Although natural killer (NK) are major cells used to treat cancer patients,
recent clinical trials showed that NK92 cells can be also used for the same purpose due to
their high anti-tumor activity. Here, we examined whether these cells might be inflammatory
due to the release of interleukin-1β (IL-1β), and whether the anti-inflammatory molecules
dimethyl fumarate (DMF), or monomethyl fumarate (MMF) impair this activity.
METHODS: NK92 cells were examined for the synthesis and release of IL-1β utilizing RT-PCR
and ELISA assay, respectively. The expression of hydroxy-carboxylic acid receptors (HCA)1,
HCA2 and HCA3 was detected by immunoblotting, flow cytometry, immunofluorescence and
RT-PCR assays. The activation of caspase-1 and Gasdermin D (GSDMD) was evaluated by
immunoblot assay. Pyroptosis was demonstrated by immunofluorescence imaging. Expression
of DNA methyltransferases (DNMTs) mRNA was determined by whole transcriptome and
immunoblot analyses.
RESULTS: LPS-induced the release of IL-1β from NK92 cells, whereas DMF or MMF inhibited
this induction. The effect of these drugs was due to inhibiting the conversion of procaspase-1
into active caspase-1. NK92 cells highly expressed GSDMD, a pyroptotic-mediated molecule.
However, LPS induced the distribution of GSDMD into the cell membranes, corroborated with
the presence of pyroptotic bodies, an activity that was inhibited by DMF or MMF. These
molecule also inhibited the generation of GSDMD through DNMT-mediated hypermethylation
of the promoter region of GSDMD gene. These results were supported by increased expression
of DNMTs mRNA as determined by whole transcriptome analysis.
DISCUSSION: Our results are the first to show that NK92 cells utilize GSDMD pathway to
release IL-1β. Further, DMF and MMF which were previously shown to enhance NK cell
cytotoxicity, also inhibit the inflammatory effects of these cells, making them most suitable
for treating cancer patients
Transient Receptor Potential (TRP) and Cch1-Yam8 Channels Play Key Roles in the Regulation of Cytoplasmic Ca2+ in Fission Yeast
The regulation of cytoplasmic Ca2+ is crucial for various cellular processes. Here, we examined the cytoplasmic Ca2+ levels in living fission yeast cells by a highly sensitive bioluminescence resonance energy transfer-based assay using GFP-aequorin fusion protein linked by 19 amino acid. We monitored the cytoplasmic Ca2+ level and its change caused by extracellular stimulants such as CaCl2 or NaCl plus FK506 (calcineurin inhibitor). We found that the extracellularly added Ca2+ caused a dose-dependent increase in the cytoplasmic Ca2+ level and resulted in a burst-like peak. The overexpression of two transient receptor potential (TRP) channel homologues, Trp1322 or Pkd2, markedly enhanced this response. Interestingly, the burst-like peak upon TRP overexpression was completely abolished by gene deletion of calcineurin and was dramatically decreased by gene deletion of Prz1, a downstream transcription factor activated by calcineurin. Furthermore, 1 hour treatment with FK506 failed to suppress the burst-like peak. These results suggest that the burst-like Ca2+ peak is dependent on the transcriptional activity of Prz1, but not on the direct TRP dephosphorylation. We also found that extracellularly added NaCl plus FK506 caused a synergistic cytosolic Ca2+ increase that is dependent on the inhibition of calcineurin activity, but not on the inhibition of Prz1. The synergistic Ca2+ increase is abolished by the addition of the Ca2+ chelator BAPTA into the media, and is also abolished by deletion of the gene encoding a subunit of the Cch1-Yam8 Ca2+ channel complex, indicating that the synergistic increase is caused by the Ca2+ influx from the extracellular medium via the Cch1-Yam8 complex. Furthermore, deletion of Pmk1 MAPK abolished the Ca2+ influx, and overexpression of the constitutively active Pek1 MAPKK enhanced the influx. These results suggest that Pmk1 MAPK and calcineurin positively and negatively regulate the Cch1-Yam8 complex, respectively, via modulating the balance between phosphorylation and dyphosphorylation state
Oxidation of benzoin catalyzed by oxovanadium (IV) schiff base complexes
BACKGROUND: The oxidative transformation of benzoin to benzil has been accomplished by the use of a wide
variety of reagents or catalysts and different reaction procedures. The conventional oxidizing agents yielded mainly
benzaldehyde or/and benzoic acid and only a trace amount of benzil. The limits of practical utilization of these
reagents involves the use of stoichiometric amounts of corrosive acids or toxic metallic reagents, which in turn
produce undesirable waste materials and required high reaction temperatures.
In recent years, vanadium complexes have attracted much attention for their potential utility as catalysts for various
types of reactions.
RESULTS: Active and selective catalytic systems of new unsymmetrical oxovanadium(IV) Schiff base complexes for
the oxidation of benzoin is reported. The Schiff base ligands are derived between 2-aminoethanol and 2-hydroxy-1-
naphthaldehyde (H2L1) or 3-ethoxy salicylaldehyde (H2L3); and 2-aminophenol and 3-ethoxysalicylaldehyde (H2L2) or
2-hydroxy-1-naphthaldehyde (H2L4). The unsymmetrical Schiff bases behave as tridentate dibasic ONO donor
ligands. Reaction of these Schiff base ligands with oxovanadyl sulphate afforded the mononuclear oxovanadium(IV)
complexes (VIVOLx.H2O), which are characterized by various physico-chemical techniques.
The catalytic oxidation activities of these complexes for benzoin were evaluated using H2O2 as an oxidant. The best
reaction conditions are obtained by considering the effect of solvent, reaction time and temperature. Under the
optimized reaction conditions, VOL4 catalyst showed high conversion (>99%) with excellent selectivity to benzil
(~100%) in a shorter reaction time compared to the other catalysts considered.
CONCLUSION: Four tridentate ONO type Schiff base ligands were synthesized. Complexation of these ligands with
vanadyl(IV) sulphate leads to the formation of new oxovanadium(IV) complexes of type VIVOL.H2O.
Elemental analyses and spectral data of the free ligands and their oxovanadium(IV) complexes were found to be in
good agreement with their structures, indicating high purity of all the compounds.
Oxovanadium complexes were screened for the oxidation of benzoin to benzil using H2O2 as oxidant. The effect of
time, solvent and temperature were optimized to obtain maximum yield. The catalytic activity results demonstrate
that these catalytic systems are both highly active and selective for the oxidation of benzoin under mild reaction
conditions.Web of Scienc
Stampidine prevents mortality in an experimental mouse model of viral hemorrhagic fever caused by lassa virus
BACKGROUND: The potential use of microorganisms as agents of biological warfare (BW) is a growing concern. Lassa virus, a member of the Arenavirus class of Hemorrhagic fever (HF) viruses has emerged as a worldwide concern among public health officials. The purpose of the present study was to further elucidate the antiviral activity spectrum of stampidine, a novel nucleoside analog with potent anti-viral activity against the immunodeficiency viruses HIV-1, HIV-2, and FIV, by examining its effects on survival of mice challenged with Lassa virus. METHODS: We examined the therapeutic effect of Stampidine in CBA mice inoculated with intracerebral injections of the Josiah strain of Lassa virus. Mice were treated either with vehicle or nontoxic doses of stampidine administered intraperitoneally 24 hours prior to, 1 hour prior to, and 24 hours, 48 hours, 72 hours, and 96 hours after virus inoculation. RESULTS: The probability of survival following the Lassa challenge was significantly improved for stampidine treated mice (Kaplan Meier, Chi-squared = 11.7, df = 2, Log-Rank p-value = 0.003). CONCLUSION: Therefore, stampidine shows clinical potential as a new agent for treatment of viral hemorrhagic fevers caused by Lassa virus
What is damaging the kidney in lupus nephritis?
Despite marked improvements in the survival of patients with severe lupus nephritis over the past 50 years, the rate of complete clinical remission after immune suppression therapy i
KINETICS OF MILLERITE DISSOLUTION IN CUPRIC CHLORIDE SOLUTIONS
Oxidation of millerite by cupric chloride in sodium chloride solutions has been studied as a function of: rate of agitation; leaching time; temperature; acid concentration; and total initial cupric concentration. The reaction has a 0.5 order of dependence on initial cupric concentration in the range 0.0-0.5 M. The activation energy for the temperature range 333-363 K was found to be 65.2 kJ/mol with chemical reaction at the mineral surface as the rate-controlling step. The rate expression, for initial cupric concentrations between 0.0 and 0.5 M, is: {1-(1-alpha)(1/3)} = {9.27 X 10(3) . [Cu(II)](0.5). r(0)(-1)exp(-7.847 X 10(3)/T)} . t according to the shrinking-core model
Synthesis, characterization and coordination chemistry of dibenzofuran derivatives of 1,4,7,10-tetraazacyclododecane
A 1,4-disubstituted dibenzofuran derivative of 1,4,7,10- tetraazacyclododecane (cyclen), L1, has been prepared by the direct reaction of cyclen and chloroacetyldibenzofuran and the mono-substituted derivative, L2, by reaction of chloroacetyldibenzofuran and 1,4,7-tris(t-butoxycarbonyl)-1,4,7,10- tetraazacyclododecane followed by deprotection with trifluoroacetic acid. The ligands were characterized by H and C NMR spectroscopy, IR spectroscopy and mass spectrometry. The reaction of the 1,4-disubstituted dibenzofuran cyclen, L1, with Cu(ClO)·6H O in methanol yielded crystals of [CuL1](ClO) ·MeOH·1/2HO that were suitable for single crystal structural analysis. The X-ray structure confirmed that the 1,4-disubstituted dibenzofuran cyclen had been formed. The copper(II) coordination sphere in the complex cation, [CuL1], is occupied by four nitrogen atoms from the macrocycle and an amide oxygen donor from one dibenzofuran pendant group. As is typical for copper(II)-cyclen complexes, the Cu(II) centre sits above the plane of the macrocycle nitrogen towards the oxygen donor, in this case by 0.5 . Fluorescence emission studies indicate that coordination of the macrocycle to either copper(II) or zinc(II) results in a decrease in emission with respect to the emission of the pure ligand
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