Complement Factor H-Related 3 (FHR-3) is a major regulator of the complement system, which is associated with different diseases, such as age-related macular degeneration (AMD). However, the non-canonical local, cellular functions of FHR-3 remained poorly understood. Here, we report that FHR-3 bound to oxidative stress epitopes and competed with FH for interaction.
View Article and Find Full Text PDFTumor-derived lactic acid inhibits T and natural killer (NK) cell function and, thereby, tumor immunosurveillance. Here, we report that melanoma patients with high expression of glycolysis-related genes show a worse progression free survival upon anti-PD1 treatment. The non-steroidal anti-inflammatory drug (NSAID) diclofenac lowers lactate secretion of tumor cells and improves anti-PD1-induced T cell killing in vitro.
View Article and Find Full Text PDFChemistry
September 2017
Vγ9Vδ2 T cells play an important role in the cross talk of the innate and adaptive immune system. For their activation by phosphoantigens (PAgs), both cell surface receptors, the eponymous Vγ9Vδ2 T cell antigen receptors (Vγ9Vδ2 TCRs) on Vγ9Vδ2 T cells and butyrophilin 3A1 (BTN3A1) on the phosphoantigen-"presenting" cell, are mandatory. To find yet undetected but further contributing proteins, a biotinylated, photo-crosslinkable benzophenone probe BioBP-HMBPP (2) was synthesized from a known allyl alcohol in nine steps and overall 16 % yield.
View Article and Find Full Text PDFPhosphoantigens (PAgs)-like HMBPP ((E)-4-hydroxy-3-methyl-but-2-enyl diphosphate) and butyrophilin 3 (BTN3A, CD277)-specific monoclonal antibody 20.1 induce TCR-mediated activation of Vγ9Vδ2 T cells. Here, we compared murine reporter cells transduced with Vγ9Vδ2 TCRs G115, D1C55, and MOP for the activation in culture with human RAJI cells and PAgs or mAb 20.
View Article and Find Full Text PDFThe JAK/STAT pathway is an essential mediator of cytokine signaling, often upregulated in human diseases and therefore recognized as a relevant therapeutic target. We previously identified the synthetic chalcone α-bromo-2',3,4,4'-tetramethoxychalcone (α-Br-TMC) as a novel JAK2/STAT5 inhibitor. We also found that treatment with α-Br-TMC resulted in a downward shift of STAT5 proteins in SDS-PAGE, suggesting a post-translational modification that might affect STAT5 function.
View Article and Find Full Text PDFInflammation plays a central role in the pathophysiology of many diseases. The inducible enzyme heme oxygenase-1 (HO-1) protects cells against inflammation and can be induced by electrophilic compounds like the chalcones (1,3-diphenylprop-2-enones) from the class of α,β-unsaturated carbonyl compounds. We hypothesized that the synthetic chalcone E-α-(p-methoxyphenyl)-2',3,4,4'-tetramethoxychalcone (E-α-p-OMe-C6H4-TMC) exerts anti-inflammatory effects in RAW264.
View Article and Find Full Text PDFCell protection against different noxious stimuli like oxidative stress or chemical toxins plays a central role in the treatment of many diseases. The inducible heme oxygenase isoform, heme oxygenase-1 (HO-1), is known to protect cells against a variety of harmful conditions including apoptosis. Because a number of medium strong electrophiles from a series of α-X-substituted 2',3,4,4'-tetramethoxychalcones (α-X-TMCs, X = H, F, Cl, Br, I, CN, Me, p-NO2-C6H4, Ph, p-OMe-C6H4, NO2, CF3, COOEt, COOH) had proven to activate Nrf2 resulting in HO-1 induction and inhibit NF-κB downstream target genes, their protective effect against staurosporine induced apoptosis and reactive oxygen species (ROS) production was investigated.
View Article and Find Full Text PDFInflammatory signaling pathways orchestrate the cellular response to infection and injury. These pathways are known to be modulated by compounds that alkylate cysteinyl thiols. One class of phytochemicals with strong thiol alkylating activity is the chalcones.
View Article and Find Full Text PDFThe upregulation of heme oxygenase-1 (HO-1) has proven to be a useful tool for fighting inflammation. In order to identify new HO-1 inducers, an efficient screening method was developed which can provide new lead structures for drug research. We designed a simple ELISA-based HO-1 enzyme activity assay, which allows for the screening of 12 compounds in parallel in the setting of a 96-well plate.
View Article and Find Full Text PDFA strategy for the synthesis of natural and non-natural 5-deoxy-6,7-dihydrocurcuminoids (diarylheptanoids) was developed for the preparation of 14 compounds with varying aromatic substituent patterns and a different functionality in the aliphatic seven-carbon chain. The in vitro protective activity against glutamate-induced neuronal cell death was examined in the murine hippocampal cell line HT-22 to find structural motifs responsible for neuroprotective effects in vitro. Among the tested compounds the ferulic acid-like unit, present in the structures of (E)-1,7-bis(4-hydroxy-3-methoxyphenyl)hept-1-en-3-one (5) and (E)-1-(4-hydroxy-3-methoxyphenyl)-7-(4-hydroxyphenyl)hept-1-en-3-one (7), appeared to be an important feature for protection against glutamate-induced neurotoxicity.
View Article and Find Full Text PDFPyrophosphorylated metabolites of isoprenoid-biosynthesis (phosphoantigens, PAgs) activate Vγ9Vδ2 T cells during infections and trigger antitumor activity. This activation depends on expression of butyrophilin 3 A1 (BTN3A1) by antigen-presenting cells. This report defines the minimal genetic requirements for activation of Vγ9Vδ2 T cells by PAgs and mAb 20.
View Article and Find Full Text PDFSignal transducer and activator of transcription STAT5 and its upstream activating kinase JAK2 are essential mediators of cytokine signaling. Their activity is normally tightly regulated and transient. However, constitutive activation of STAT5 is found in numerous cancers and a driving force for malignant transformation.
View Article and Find Full Text PDFThiol-mediated processes play a key role to induce or inhibit inflammation proteins. Tailoring the reactivity of electrophiles can enhance the selectivity to address only certain surface cysteines. Fourteen 2',3,4,4'-tetramethoxychalcones with different α-X substituents (X=H, F, Cl, Br, I, CN, Me, p-NO2-C6H4, Ph, p-OMe-C6H4, NO2, CF3, COOEt, COOH) were synthesized, containing the potentially electrophilic α,β-unsaturated carbonyl unit.
View Article and Find Full Text PDFThe first total synthesis of either enantiomer of Arteludovicinolide A and their biological evaluation is reported, featuring a new strategy for the asymmetric construction of γ-butyrolactones with stereogenic side chains in the 4-position. Starting from the renewable resource methyl 2-furoate, the sesquiterpene lactone was synthesized in 9 steps and 4.8% overall yield via an asymmetric cyclopropanation and two diastereoselective nucleophile additions making use of a donor-acceptor-cyclopropane-lactonization cascade.
View Article and Find Full Text PDFThe electrophilic nature of chalcones (1,3-diphenylprop-2-en-1-ones) and many other α,β-unsaturated carbonyl compounds is crucial for their biological activity, which is often based on thiol-mediated regulation processes. To better predict their biological activity a simple screening assay for the assessment of the second-order rate constants (k(2)) in thia-Michael additions was developed. Hence, a clear structure-activity relationship of 16 differentially decorated hydroxy-alkoxychalcones upon addition of cysteamine could be established.
View Article and Find Full Text PDFA series of η(4)-acyloxycyclohexadiene-Fe(CO)(3) complexes was prepared and fully characterized by spectroscopic methods including single crystal X-ray diffraction. For this purpose a new synthetic access to differently acylated 1,3- and 1,5-dienol-Fe(CO)(3) complexes was developed. The enzymatically triggered CO release from these compounds was monitored (detection of CO through GC and/or by means of a myoglobin assay) and the anti-inflammatory effect of the compounds was assessed by a cellular assay based on the inhibition of NO-production by inducible NO synthase (iNOS).
View Article and Find Full Text PDFalpha,beta-Unsaturated carbonyl compounds as potential drug candidates is a controversial topic since their potential Michael acceptor activity can lead to cell damage and cytotoxicity. Nevertheless, the alpha,beta-unsaturated carbonyl functionality can be employed as a tool to fine tune biological activity by directly manipulating this entity. Depending on their electronic properties, alpha,beta-unsaturated carbonyl functionalities display different reactivities, namely Michael addition, radical scavenging, oxidation or double bond isomerization.
View Article and Find Full Text PDF(E)-1-Hydroxy-2-methyl-but-2-enyl 4-diphosphate, a recently discovered intermediate in the deoxyxylulose phosphate pathway of isoprenoid biosynthesis, has been shown to act as a potent immunomodulator. In cultures of human peripheral blood mononuclear cells from eight non-related donors, the compound stimulated the proliferation of Vgamma9/Vdelta2 T lymphocytes with a median EC(50) of 70 pM when 10 U/ml of IL-2 was used as costimulant. Isopentenyl diphosphate (IPP), dimethylallyl diphosphate (DMAPP) and some structural analogs of (E)-1-hydroxy-2-methyl-but-2-enyl 4-diphosphate also stimulated Vgamma9/Vdelta2 T-cell proliferation, albeit at much higher concentrations.
View Article and Find Full Text PDFThe ispH gene of Escherichia coli specifies an enzyme catalyzing the conversion of 1-hydroxy-2-methyl-2-(E)-butenyl diphosphate into a mixture of isopentenyl diphosphate (IPP) and dimethylallyl diphosphate (DMAPP) in the nonmevalonate isoprenoid biosynthesis pathway. The implementation of a gene cassette directing the overexpression of the isc operon involved in the assembly of iron-sulfur clusters into an Escherichia coli strain engineered for ispH gene expression increased the catalytic activity of IspH protein anaerobically purified from this strain by a factor of at least 200. For maximum catalytic activity, flavodoxin and flavodoxin reductase were required in molar concentrations of 40 and 12 microM, respectively.
View Article and Find Full Text PDFAn open reading frame (Acc. no. P50740) on the Bacillus subtilis chromosome extending from bp 184,997-186,043 with similarity to the idi-2 gene of Streptomyces sp.
View Article and Find Full Text PDFOn the basis of the earlier examples of diazopyruvoyl (DAP) groups reported by Lawton for covalent binding and cross-linking of proteins and oligopeptides and our recent demonstration that a coumaryl diazopyruvamide was used to label Type-I collagen, we have extended our investigations to the synthesis and cross-linking capabilities of a bis-DAP polyethylene glycol to cross-link Type-I collagen. The new photoactivated cross-linking agent, N,N'-bis(3-diazopyruvoyl)-2,2'-(ethylenedioxy)bis(ethylamine) (DPD, 2), has been designed and synthesized specifically to "weld" collagenous tissues by cross-linking Type-I collagen. A working model for the photochemical welding studies of collagenous tissues was developed using gelatin strips (gel strips) composed of denatured Type-I collagen.
View Article and Find Full Text PDFEarlier in vivo studies have shown that the sequential action of the IspG and IspH proteins is essential for the reductive transformation of 2C-methyl-d-erythritol 2,4-cyclodiphosphate into dimethylallyl diphosphate and isopentenyl diphosphate via 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate. A recombinant fusion protein comprising maltose binding protein and IspG protein domains was purified from a recombinant Escherichia coli strain. The purified protein failed to transform 2C-methyl-d-erythritol 2,4-cyclodiphosphate into 1-hydroxy-2-methyl-2-(E)-butenyl 4-diphosphate, but catalytic activity could be restored by the addition of crude cell extract from an ispG-deficient E.
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