Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) main protease (Mpro) autocatalytically releases itself out of the viral polyprotein to form a fully active mature dimer in a manner that is not fully understood. Here, we introduce several tools to help elucidate differences between cis (intramolecular) and trans (intermolecular) proteolytic processing and to evaluate inhibition of precursor Mpro. We found that many mutations at the P1 position of the N-terminal autoprocessing site do not block cis autoprocessing but do inhibit trans processing. Notably, substituting the WT glutamine at the P1 position with isoleucine retains Mpro in an unprocessed precursor form that can be purified and further studied. We also developed a cell-based reporter assay suitable for compound library screening and evaluation in HEK293T cells. This assay can detect both overall Mpro inhibition and the fraction of uncleaved precursor form of Mpro through separable fluorescent signals. We observed that inhibitory compounds preferentially block mature Mpro. Bofutrelvir and a novel compound designed in-house showed the lowest selectivity between precursor and mature Mpro, indicating that inhibition of both forms may be possible. Additionally, we observed positive modulation of precursor activity at low concentrations of inhibitors. Our findings help expand understanding of the SARS-CoV-2 viral life cycle and may facilitate development of strategies to target precursor form of Mpro for inhibition or premature activation of Mpro.

• MeSH
• antivirové látky * farmakologie   chemie   MeSH
• farmakoterapie COVID-19 MeSH
• HEK293 buňky MeSH
• inhibitory proteas farmakologie   chemie   MeSH
• koronavirové proteasy 3C * metabolismus   antagonisté a inhibitory   chemie   genetika   MeSH
• lidé MeSH
• mutace MeSH
• objevování léků * metody   MeSH
• proteolýza MeSH
• SARS-CoV-2 * enzymologie   účinky léků   metabolismus   genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

BACKGROUND: Diffuse midline glioma, H3 K27-altered (DMG) is a fatal tumour that arises in the midline structures of the brain. When located in the pons, it is more commonly referred to as diffuse intrinsic pontine glioma (DIPG). DMG/DIPG is usually diagnosed when children are < 10 years, and it has a median overall survival of < 12 months after diagnosis. Radiological imaging is still the gold standard for DIPG diagnosis while the use of biopsy procedures led to our knowledge on its biology, such as with the identification of the canonical histone H3K27M mutation. However, the need to improve survival encourages the development of non-invasive, fast and inexpensive assays on biofluids for optimizing molecular diagnoses in DMG/DIPG. Here, we propose a rapid, new, imaging and epigenetics-based approach to diagnose DMG/DIPG in the plasma of paediatric patients. METHODS: A total of 20 healthy children (mean age: 10.5 years) and 24 children diagnosed with DMG/DIPG (mean age: 8.5 years) were recruited. Individual histones (H2A, H2B, H3, H4, macroH2A1.1 and macroH2A1.2), histone dimers and nucleosomes were assayed in biofluids by means of a new advanced flow cytometry ImageStream(X)-adapted method. RESULTS: We report a significant increase in circulating histone dimers and tetramers (macroH2A1.1/H2B versus control: p value < 0.0001; macroH2A1.2/H2B versus control: p value < 0.0001; H2A/H2B versus control: p value < 0.0001; H3/H4 versus control: p value = 0.008; H2A/H2B/H3/H4 versus control: p value < 0.0001) and a significant downregulation of individual histones (H2B versus control: p value < 0.0001; H3 versus control: p value < 0.0001; H4 versus control: p value < 0.0001). Moreover, histones were also detectable in the cerebrospinal fluid (CSF) of patients with DMG/DIPG and in the supernatant of SF8628, OPBG-DIPG002 and OPBG-DIPG004 DMG/DIPG cell lines, with patterns mostly similar to each other, but distinct compared to blood plasma. CONCLUSIONS: In summary, we identified circulating histone signatures able to detect the presence of DMG/DIPG in biofluids of children, using a rapid and non-invasive ImageStream(X)-based imaging technology, which may improve diagnosis and benefit the patients.

• MeSH
• difuzní intrinsický pontinní gliom genetika   diagnóza   krev   MeSH
• dítě MeSH
• epigeneze genetická MeSH
• gliom genetika   diagnóza   krev   patologie   diagnostické zobrazování   MeSH
• histony * genetika   metabolismus   krev   MeSH
• lidé MeSH
• mladiství MeSH
• mutace MeSH
• nádorové biomarkery krev   MeSH
• nádory mozkového kmene genetika   diagnóza   krev   diagnostické zobrazování   patologie   metabolismus   MeSH
• předškolní dítě MeSH
• Check Tag
• dítě MeSH
• lidé MeSH
• mladiství MeSH
• mužské pohlaví MeSH
• předškolní dítě MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

OBJECTIVES: To compare the drug survival of etanercept to monoclonal tumour necrosis factor-α inhibitors in rheumatoid arthritis, ankylosing spondylitis and psoriatic arthritis. METHODS: Patients initiating first line biological therapy with tumour necrosis factor-α were propensity score matched and compared for drug survival with a Kaplan-Meier analysis. RESULTS: We matched 657 to 657 patients in rheumatoid arthritis, the median survival time on etanercept was 44.6 months vs. 36.8 months on monoclonal antibody tumour necrosis factor-α inhibitors, with a hazard ratio of 0.94, p = 0.416 We matched 187 to 356 patients in ankylosing spondylitis, the median survival time on etanercept was 75.1 compared to 68.0 months, hazard ratio of 0.78, p = 0.087 We matched 81 to 160 psoriatic arthritis patients, the median survival time on etanercept was 35.8. compared to 65.7 months, hazard ratio 1.61, p = 0.011. Patients treated with etanercept had significantly worse psoriasis scoring during follow up. CONCLUSIONS: We found comparable survival in rheumatoid arthritis and ankylosing spondylitis. In psoriatic arthritis, we found significantly shorter survival on etanercept, possibly due to worse response of skin and nail manifestations.

• MeSH
• adalimumab terapeutické užití   MeSH
• ankylózující spondylitida * farmakoterapie   mortalita   MeSH
• antirevmatika * terapeutické užití   MeSH
• dospělí MeSH
• etanercept * terapeutické užití   MeSH
• infliximab terapeutické užití   MeSH
• Kaplanův-Meierův odhad MeSH
• lidé středního věku MeSH
• lidé MeSH
• monoklonální protilátky terapeutické užití   MeSH
• psoriatická artritida * farmakoterapie   mortalita   MeSH
• registrace * MeSH
• revmatoidní artritida * farmakoterapie   mortalita   MeSH
• senioři MeSH
• tendenční skóre * MeSH
• TNF-alfa * antagonisté a inhibitory   MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Geografické názvy
• Česká republika MeSH

The activity of the light-oxygen-voltage/helix-turn-helix (LOV-HTH) photoreceptor EL222 is regulated through protein-protein and protein-DNA interactions, both triggered by photo-excitation of its flavin mononucleotide (FMN) cofactor. To gain molecular-level insight into the photocycle of EL222, we applied complementary methods: macromolecular X-ray crystallography (MX), nuclear magnetic resonance (NMR) spectroscopy, optical spectroscopies (infrared and UV-visible), molecular dynamics/metadynamics (MD/metaD) simulations, and protein engineering using noncanonical amino acids. Kinetic experiments provided evidence for two distinct EL222 conformations (lit1 and lit2) that become sequentially populated under illumination. These two lit states were assigned to covalently bound N5 protonated, and noncovalently bound hydroquinone forms of FMN, respectively. Only subtle structural differences were observed between the monomeric forms of all three EL222 species (dark, lit1, and lit2). While the dark state is largely monomeric, both lit states undergo monomer-dimer exchange. Furthermore, molecular modeling revealed differential dynamics and interdomain separation times arising from the three FMN states (oxidized, adduct, and reduced). Unexpectedly, all three EL222 species can associate with DNA, but only upon blue-light irradiation, a high population of stable complexes is obtained. Overall, we propose a model of EL222 activation where photoinduced changes in the FMN moiety shift the population equilibrium toward an open conformation that favors self-association and DNA-binding.

• MeSH
• bakteriální proteiny chemie   metabolismus   MeSH
• DNA vazebné proteiny chemie   metabolismus   MeSH
• DNA * chemie   metabolismus   MeSH
• flavinmononukleotid * chemie   metabolismus   MeSH
• flaviny chemie   metabolismus   MeSH
• kinetika MeSH
• konformace proteinů MeSH
• krystalografie rentgenová MeSH
• oxidace-redukce * MeSH
• simulace molekulární dynamiky MeSH
• světlo * MeSH
• Thermosynechococcus metabolismus   MeSH
• transkripční faktory metabolismus   chemie   MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH

Monocyclic monoterpenoids carvones have been recently identified as atypical negative allosteric modulators of aryl hydrocarbon receptor (AhR). In the current work, we performed AhR antagonist activity screening of 100 natural and synthetic monoterpenoids, and their analogues. Using SAR approach, structural determinants of AhR antagonist activity were assigned, including CO presence/position, planarity, and C3/C5-alkylation. Applying pyramidal selection criteria, including absence of residual agonist activity, no cytotoxicity, strong antagonist potency, and pan-antagonism against diverse AhR agonists, we distilled four lead AhR antagonists (carvacrol, o-cresol, 3-methyl-S-carvone, EN-2). Whereas 3-methyl-S-carvone and EN-2 were non-competitive AhR pan-antagonists, carvacrol and o-cresol were ligand-selective AhR antagonists acting by unclear mechanism. We characterized in detail the effects of lead compounds at cellular functions of AhR, including AhR nuclear translocation, AhR dimerization with ARNT, and the expression of AhR-regulated genes. As a proof of concept, effects of monoterpenoids in the murine macrophages were investigated.

• MeSH
• lidé MeSH
• molekulární struktura MeSH
• monoterpeny * farmakologie   chemie   chemická syntéza   MeSH
• myši MeSH
• receptory aromatických uhlovodíků * metabolismus   antagonisté a inhibitory   MeSH
• vztah mezi dávkou a účinkem léčiva MeSH
• vztahy mezi strukturou a aktivitou MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

An activity-guided isolation study on the EtOH extract prepared from the bulbs of Prospero autumnale yielded four new phenolic compounds, including a new stilbenoid (1), a new homoisoflavonoid derivative (8), a new homoisoflavonoid dimer (9), and an unprecedented homoisoflavone-stilbene heterodimer (10), together with six known (2-7) analogs. Their chemical structures were elucidated by spectroscopic analysis and theoretical NMR and ECD calculations. Compounds 9 and 10 are unique in their scaffolds. The in vitro cytotoxic activity of purified compounds was evaluated against eight tumor cell lines (HCT116, LoVo, DU145, PC3, HEP3B, HEPG2, MCF7, and MDA-MB-231) and one nontumor cell line (L929) by the MTS assay. Compounds 1, 2, 4, and 10 exhibited inhibition with IC50 values ranging from 8.2 to 37.6 μM. Cytotoxic cell death mechanisms were further investigated, indicating variability in apoptosis, necrosis, or cell cycle arrest.

• MeSH
• apoptóza účinky léků   MeSH
• fytogenní protinádorové látky * farmakologie   chemie   MeSH
• isoflavony farmakologie   chemie   izolace a purifikace   MeSH
• kořeny rostlin chemie   MeSH
• lidé MeSH
• molekulární struktura MeSH
• nádorové buněčné linie MeSH
• screeningové testy protinádorových léčiv MeSH
• stilbeny * farmakologie   chemie   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

Protein synthesis (translation) consumes a substantial proportion of cellular resources, prompting specialized mechanisms to reduce translation under adverse conditions. Ribosome inactivation often involves ribosome-interacting proteins. In both bacteria and eukaryotes, various ribosome-interacting proteins facilitate ribosome dimerization or hibernation, and/or prevent ribosomal subunits from associating, enabling the organisms to adapt to stress. Despite extensive studies on bacteria and eukaryotes, understanding factor-mediated ribosome dimerization or anti-association in archaea remains elusive. Here, we present cryo-electron microscopy structures of an archaeal 30S dimer complexed with an archaeal ribosome dimerization factor (designated aRDF), from Pyrococcus furiosus, resolved at a resolution of 3.2 Å. The complex features two 30S subunits stabilized by aRDF homodimers in a unique head-to-body architecture, which differs from the disome architecture observed during hibernation in bacteria and eukaryotes. aRDF interacts directly with eS32 ribosomal protein, which is essential for subunit association. The binding mode of aRDF elucidates its anti-association properties, which prevent the assembly of archaeal 70S ribosomes.

• MeSH
• archeální proteiny * chemie   metabolismus   ultrastruktura   MeSH
• dimerizace MeSH
• elektronová kryomikroskopie * MeSH
• malé podjednotky ribozomu archebakteriální chemie   metabolismus   MeSH
• molekulární modely MeSH
• multimerizace proteinu MeSH
• Pyrococcus furiosus * metabolismus   MeSH
• ribozomální proteiny * chemie   metabolismus   MeSH
• ribozomy metabolismus   ultrastruktura   chemie   MeSH
• vazba proteinů MeSH
• Publikační typ
• časopisecké články MeSH

Activation of the Wnt/β-catenin pathway crucially depends on the polymerization of dishevelled 2 (DVL2) into biomolecular condensates. However, given the low affinity of known DVL2 self-interaction sites and its low cellular concentration, it is unclear how polymers can form. Here, we detect oligomeric DVL2 complexes at endogenous protein levels in human cell lines, using a biochemical ultracentrifugation assay. We identify a low-complexity region (LCR4) in the C-terminus whose deletion and fusion decreased and increased the complexes, respectively. Notably, LCR4-induced complexes correlated with the formation of microscopically visible multimeric condensates. Adjacent to LCR4, we mapped a conserved domain (CD2) promoting condensates only. Molecularly, LCR4 and CD2 mediated DVL2 self-interaction via aggregating residues and phenylalanine stickers, respectively. Point mutations inactivating these interaction sites impaired Wnt pathway activation by DVL2. Our study discovers DVL2 complexes with functional importance for Wnt/β-catenin signaling. Moreover, we provide evidence that DVL2 condensates form in two steps by pre-oligomerization via high-affinity interaction sites, such as LCR4, and subsequent condensation via low-affinity interaction sites, such as CD2.

• MeSH
• beta-katenin metabolismus   genetika   MeSH
• HEK293 buňky MeSH
• lidé MeSH
• multimerizace proteinu MeSH
• protein dishevelled * metabolismus   genetika   MeSH
• signální dráha Wnt * MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH

The cellular adhesion receptor αvβ6-integrin is highly expressed in many cancers, e.g., pancreatic, lung, head-and-neck, cervical, bladder, and esophageal carcinoma. Multimerization of αvβ6-integrin-specific RGD peptides increases the target affinity and retention but affects biodistribution and pharmacokinetics. Amide formation of the terminal carboxylic acid moieties of the square-symmetrical bifunctional chelator DOTPI with 3-azidopropylamine yields derivatives with 4, 3, and 2 terminal azides and zero, 1, and 2 remaining carboxylic acids, respectively, whereby formation of the 2-cis-isomer is preferred according to NMR investigation of the Eu(III)-complexes. Cu(II)-catalyzed alkyne-azide cycloaddition (CuAAC) of the alkyne-functionalized αvβ6-integrin binding peptide cyclo[YRGDLAYp(NMe)K(pent-4-ynoic amide)] (Tyr2) yields the respective di-, tri-, and tetrameric conjugates for Lu-177-labeling. In mice bearing αvβ6-integrin-expressing xenografts of H2009 (human lung adenocarcinoma) cells, the Lu-177-labeled trimer's tumor-to-blood ratio of 112 exceeds that of the tetramer (10.4) and the dimer (54). Co-infusion of gelofusine (succinylated gelatin) reduces the renal uptake of the trimer by 89%, resulting in a 10-fold better tumor-to-kidney ratio, while no improvement of that ratio is observed with arginine/lysine, para-aminohippuric acid (PAH), and hydroxyethyl starch (HES) coinfusions. Since the Lu-177-labeled Tyr2-trimer outperforms the dimer and the tetramer, such trimers are considered the best lead structures for the ongoing development of αvβ6-integrin targeted anticancer theranostics.

• MeSH
• antigeny nádorové * metabolismus   MeSH
• chelátory * chemie   MeSH
• click chemie MeSH
• integriny * metabolismus   MeSH
• lidé MeSH
• lutecium * chemie   MeSH
• myši nahé MeSH
• myši MeSH
• nádorové buněčné linie MeSH
• nádory farmakoterapie   MeSH
• oligopeptidy * chemie   farmakokinetika   MeSH
• radiofarmaka farmakokinetika   chemie   terapeutické užití   MeSH
• radionuklidy * chemie   MeSH
• teranostická nanomedicína metody   MeSH
• tkáňová distribuce MeSH
• zvířata MeSH
• Check Tag
• lidé MeSH
• myši MeSH
• zvířata MeSH
• Publikační typ
• časopisecké články MeSH

G-quadruplexes (G4s) formed within RNA are emerging as promising targets for therapeutic intervention in cancer, neurodegenerative disorders and infectious diseases. Sequences containing a succession of short GG blocks, or uneven G-tract lengths unable to form three-tetrad G4s (GG motifs), are overwhelmingly more frequent than canonical motifs involving multiple GGG blocks. We recently showed that DNA is not able to form stable two-tetrad intramolecular parallel G4s. Whether RNA GG motifs can form intramolecular G4s under physiological conditions and play regulatory roles remains a burning question. In this study, we performed a systematic analysis and experimental evaluation of a number of biologically important RNA regions involving RNA GG motifs. We show that most of these motifs do not form stable intramolecular G4s but need to dimerize to form stable G4 structures. The strong tendency of RNA GG motif G4s to associate may participate in RNA-based aggregation under conditions of cellular stress.

• MeSH
• dimerizace MeSH
• G-kvadruplexy * MeSH
• genetická transkripce MeSH
• lidé MeSH
• nukleotidové motivy * MeSH
• RNA * chemie   metabolismus   genetika   MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH