scholarly journals Conversion of Membrane-bound Fas(CD95) Ligand to Its Soluble Form Is Associated with Downregulation of Its Proapoptotic Activity and Loss of Liver Toxicity

1998 ◽  
Vol 187 (8) ◽  
pp. 1205-1213 ◽  
Author(s):  
Pascal Schneider ◽  
Nils Holler ◽  
Jean-Luc Bodmer ◽  
Michael Hahne ◽  
Karl Frei ◽  
...  
Keyword(s):  
Fas Ligand ◽  
Liver Toxicity ◽  
Proteolytic Processing ◽  
Soluble Form ◽  
Cross Linking ◽  
Trail Receptors ◽  
Membrane Bound ◽  
Apoptotic Activity

Human Fas ligand (L) (CD95L) and tumor necrosis factor (TNF)-α undergo metalloproteinase-mediated proteolytic processing in their extracellular domains resulting in the release of soluble trimeric ligands (soluble [s]FasL, sTNF-α) which, in the case of sFasL, is thought to be implicated in diseases such as hepatitis and AIDS. Here we show that the processing of sFasL occurs between Ser126 and Leu127. The apoptotic-inducing capacity of naturally processed sFasL was reduced by >1,000-fold compared with membrane-bound FasL, and injection of high doses of recombinant sFasL in mice did not induce liver failure. However, soluble FasL retained its capacity to interact with Fas, and restoration of its cytotoxic activity was achieved both in vitro and in vivo with the addition of cross-linking antibodies. Similarly, the marginal apoptotic activity of recombinant soluble TNF-related apoptosis-inducing ligand (sTRAIL), another member of the TNF ligand family, was greatly increased upon cross-linking. These results indicate that the mere trimerization of the Fas and TRAIL receptors may not be sufficient to trigger death signals. Thus, the observation that sFasL is less cytotoxic than membrane-bound FasL may explain why in certain types of cancer, systemic tissue damage is not detected, even though the levels of circulating sFasL are high.

scholarly journals CdtC-Induced Processing of Membrane-Bound CdtA Is a Crucial Step inAggregatibacter actinomycetemcomitansCytolethal Distending Toxin Holotoxin Formation

2017 ◽  
Vol 86 (3) ◽  
Author(s):  
Keiko Tsuruda ◽  
Oranart Matangkasombut ◽  
Masaru Ohara ◽  
Motoyuki Sugai
Keyword(s):  
Mammalian Cells ◽  
Proteolytic Processing ◽  
Content Type ◽  
Protein Toxin ◽  
Sequential Event ◽  
Membrane Bound ◽  
Processed Form ◽  
Rapid Processing

ABSTRACTAggregatibacter actinomycetemcomitansis an oral pathogen causing periodontal disease and bacterial endocarditis. It produces cytolethal distending toxin (CDT) that could damage mammalian cells and tissues. CDT is a tripartite protein toxin composed of CdtA, CdtB, and CdtC. We have previously indicated that CdtA is a lipoprotein and that the proteolytic processing of CdtA is important for biogenesis and secretion of CDT holotoxin. Here, we established anin vitroprocessing assay of CdtA and investigated the interactions of CdtA with other Cdt subunits. This assay demonstrated that incubation of membrane-bound CdtA (MCdtA), CdtB, and CdtC immediately generated a processed form of CdtA (CdtA′), which is recovered from the soluble fraction. In contrast, incubation of soluble membrane-unbound CdtA with CdtB and CdtC did not yield any CdtA′. Furthermore, incubation of CdtC with MCdtA was enough to induce rapid processing of MCdtA, whereas CdtB alone was unable to induce the processing. Coimmunoprecipitation demonstrated that CdtA′ and CdtC formed a complex. Furthermore, subsequent addition of CdtB to this reaction mixture resulted in complete CDT holotoxin complex. The cytolethal distending activity assay demonstrated that CDT complex containing CdtA′ showed far stronger cytotoxicity than that containing CdtA. Collectively, our data suggest that CDT holotoxin formationin vivois a sequential event: interaction of MCdtA and CdtC induces proteolytic processing of MCdtA, and the released CdtA′ forms a complex with CdtC. Subsequent binding of CdtB to the CdtA′/CdtC complex results in CDT holotoxin formation.

scholarly journals Inhibition of intracellular proteolytic processing of soluble proproteins by an engineered α2-macroglobulin containing a furin recognition sequence in the bait region

1997 ◽  
Vol 326 (2) ◽  
pp. 507-514 ◽  
Author(s):  
Luc VAN ROMPAEY ◽  
Torik AYOUBI ◽  
Wim VAN DE VEN ◽  
Peter MARYNEN
Keyword(s):  
Transforming Growth Factor ◽  
Transforming Growth Factor Β1 ◽  
Proteolytic Processing ◽  
Soluble Form ◽  
Recognition Sequence ◽  
Bait Region ◽  
Α2 Macroglobulin ◽  
Ester Formation ◽  
Membrane Bound

The bait region of the general protease inhibitor α2-macroglobulin (α2M) was mutated by introducing a recognition sequence of furin. This did not interfere with folding, S-ester formation or tetramerization of the mutant recombinant α2M (rα2M). Mutant rα2M inhibited furin in vitro, by a similar mechanism to that used by plasma α2M to inhibit high-molecular-mass proteases. The mutant α2M was intracellularly active in COS-1 cells in inhibiting the endogenous processing of the soluble substrates for furin (von Willebrand factor, transforming growth factor β1 and a soluble form of the envelope glycoprotein gp160 from HIV-1) but not the membrane-bound form of gp160. The intracellular activity of mutant α2M strongly indicated that α2M attains its native conformation, and thus that the unusual internal S-ester is formed, before α2M passes through the cleavage compartment(s). Our results show for the first time that modulation of the bait region of α2M allows the creation of an inhibitor against membrane-bound proteases. It can be expected that the use of α2M-bait mutants will become important as a technique for the study of various proteolytic processes and for the identification of the proteases involved.

Half-Life of Platelet Factor 4 (PF-4) in Plasma and Platelets from Macaca Mulatta

1977 ◽  
Vol 37 (01) ◽  
pp. 073-080 ◽  
Author(s):  
Knut Gjesdal ◽  
Duncan S. Pepper
Keyword(s):  
Macaca Mulatta ◽  
Half Life ◽  
Human Platelet ◽  
Gel Filtration ◽  
Platelet Factor 4 ◽  
Active Protein ◽  
Platelet Factor ◽  
Membrane Bound

SummaryHuman platelet factor 4 (PF-4) showed a reaction of complete identity with PF-4 from Macaca mulatta when tested against rabbit anti-human-PF-4. Such immunoglobulin was used for quantitative precipitation of in vivo labelled PF-4 in monkey serum. The results suggest that the active protein had an intra-platelet half-life of about 21 hours. In vitro 125I-labelled human PF-4 was injected intravenously into two monkeys and isolated by immuno-precipita-tion from platelet-poor plasma and from platelets disrupted after gel-filtration. Plasma PF-4 was found to have a half-life of 7 to 11 hours. Some of the labelled PF-4 was associated with platelets and this fraction had a rapid initial disappearance rate and a subsequent half-life close to that of plasma PF-4. The results are compatible with the hypothesis that granular PF-4 belongs to a separate compartment, whereas membrane-bound PF-4 and plasma PF-4 may interchange.

Phytosomal Curcumin Elicits Anti-tumor Properties Through Suppression of Angiogenesis, Cell Proliferation and Induction of Oxidative Stress in Colorectal Cancer

2019 ◽  
Vol 24 (39) ◽  
pp. 4626-4638 ◽  
Author(s):  
Reyhaneh Moradi-Marjaneh ◽  
Seyed M. Hassanian ◽  
Farzad Rahmani ◽  
Seyed H. Aghaee-Bakhtiari ◽  
Amir Avan ◽  
...  
Keyword(s):  
Oxidative Stress ◽  
Colorectal Cancer ◽  
Therapeutic Potential ◽  
Vegf Signaling ◽  
Anticancer Effects ◽  
Inhibition Of Angiogenesis ◽  
Underlying Mechanisms ◽  
Apoptotic Activity

Background: Colorectal cancer (CRC) is one of the most common causes of cancer-associated mortality in the world. Anti-tumor effect of curcumin has been shown in different cancers; however, the therapeutic potential of novel phytosomal curcumin, as well as the underlying molecular mechanism in CRC, has not yet been explored. Methods: The anti-proliferative, anti-migratory and apoptotic activity of phytosomal curcumin in CT26 cells was assessed by MTT assay, wound healing assay and Flow cytometry, respectively. Phytosomal curcumin was also tested for its in-vivo activity in a xenograft mouse model of CRC. In addition, oxidant/antioxidant activity was examined by DCFH-DA assay in vitro, measurement of malondialdehyde (MDA), Thiol and superoxidedismutase (SOD) and catalase (CAT) activity and also evaluation of expression levels of Nrf2 and GCLM by qRT-PCR in tumor tissues. In addition, the effect of phytosomal curcumin on angiogenesis was assessed by the measurement of VEGF-A and VEGFR-1 and VEGF signaling regulatory microRNAs (miRNAs) in tumor tissue. Results: Phytosomal curcumin exerts anti-proliferative, anti-migratory and apoptotic activity in-vitro. It also decreases tumor growth and augmented 5-fluorouracil (5-FU) anti-tumor effect in-vivo. In addition, our data showed that induction of oxidative stress and inhibition of angiogenesis through modulation of VEGF signaling regulatory miRNAs might be underlying mechanisms by which phytosomal curcumin exerted its antitumor effect. Conclusion: Our data confirmed this notion that phytosomal curcumin administrates anticancer effects and can be used as a complementary treatment in clinical settings.

scholarly journals 68Ga-Radiolabeling and Pharmacological Characterization of a Kit-Based Formulation of the Gastrin-Releasing Peptide Receptor (GRP-R) Antagonist RM2 for Convenient Preparation of [68Ga]Ga-RM2

Pharmaceutics ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 1160
Author(s):  
Adrien Chastel ◽  
Delphine Vimont ◽  
Stephane Claverol ◽  
Marion Zerna ◽  
Sacha Bodin ◽  
...  
Keyword(s):  
Calcium Mobilization ◽  
Pharmacological Characterization ◽  
Peptide Receptor ◽  
Gastrin Releasing Peptide ◽  
Production Route ◽  
Membrane Bound ◽  
One Year ◽  
Calcium Mobilization Assay

Background: [68Ga]Ga-RM2 is a potent Gastrin-Releasing Peptide-receptor (GRP-R) antagonist for imaging prostate cancer and breast cancer, currently under clinical evaluation in several specialized centers around the world. Targeted radionuclide therapy of GRP-R-expressing tumors is also being investigated. We here report the characteristics of a kit-based formulation of RM2 that should ease the development of GRP-R imaging and make it available to more institutions and patients. Methods: Stability of the investigated kits over one year was determined using LC/MS/MS and UV-HPLC. Direct 68Ga-radiolabeling was optimized with respect to buffer (pH), temperature, reaction time and shaking time. Conventionally prepared [68Ga]Ga-RM2 using an automated synthesizer was used as a comparator. Finally, the [68Ga]Ga-RM2 product was assessed with regards to hydrophilicity, affinity, internalization, membrane bound fraction, calcium mobilization assay and efflux, which is a valuable addition to the in vivo literature. Results: The kit-based formulation, kept between 2 °C and 8 °C, was stable for over one year. Using acetate buffer pH 3.0 in 2.5–5.1 mL total volume, heating at 100 °C during 10 min and cooling down for 5 min, the [68Ga]Ga-RM2 produced by kit complies with the requirements of the European Pharmacopoeia. Compared with the module production route, the [68Ga]Ga-RM2 produced by kit was faster, displayed higher yields, higher volumetric activity and was devoid of ethanol. In in vitro evaluations, the [68Ga]Ga-RM2 displayed sub-nanomolar affinity (Kd = 0.25 ± 0.19 nM), receptor specific and time dependent membrane-bound fraction of 42.0 ± 5.1% at 60 min and GRP-R mediated internalization of 24.4 ± 4.3% at 30 min. The [natGa]Ga-RM2 was ineffective in stimulating intracellular calcium mobilization. Finally, the efflux of the internalized activity was 64.3 ± 6.5% at 5 min. Conclusion: The kit-based formulation of RM2 is suitable to disseminate GRP-R imaging and therapy to distant hospitals without complex radiochemistry equipment.

scholarly journals Satureja subspicata and S. horvatii Extracts Induce Overexpression of the BCl-2 Family of Anti-apoptotic Genes and Reduce Micronuclei Frequency in Mice

2018 ◽  
Vol 13 (6) ◽  
pp. 1934578X1801300
Author(s):  
Jasmina Čakar ◽  
Naida Kadrić Lojo ◽  
Anja Haverić ◽  
Maida Hadžić ◽  
Lejla Lasić ◽  
...  
Keyword(s):  
Human Lymphocyte ◽  
Micronucleus Assay ◽  
Balkan Peninsula ◽  
Lymphocyte Culture ◽  
Cytotoxic Activities ◽  
Cytotoxic Effects ◽  
Apoptotic Genes ◽  
Apoptotic Activity

Satureja subspicata and S. horvatii are endemic species of the Balkan Peninsula and often used in traditional medicine in Bosnia and Herzegovina to treat different health conditions. We aimed to analyze the unevaluated apoptotic, genotoxic and cytotoxic effects of two Satureja species, as well as their content of phenolics that are mainly responsible for the plant's biological activity. Apoptotic and geno/cytotoxic activities of S. subspicata and S. horvatii were investigated in vitro in human lymphocyte culture and in vivo in mice. The content of the main phenolics in plant extracts was determined by ultra-high pressure liquid chromatography-MS-MS (UHPLC–MS/MS). Genotoxic and cytotoxic activities of Satureja extracts were evaluated in vitro by applying a cytokinesis-block micronucleus cytome assay in human lymphocyte culture and in vivo applying a mice reticulocytes micronucleus assay. SALSA RT-MLPA R011-C1 apoptosis assay was used for measuring the relative expression of 44 genes associated with the regulation of the apoptotic pathways in human lymphocyte cultures treated with different concentrations of two Satureja extracts. The first analysis of phenolic compounds in S. horvatii and S. subspicata determined by an UHPLC-MS/MS method revealed high levels of rosmarinic and caffeic acids. Minor genotoxic potential was determined in relation to the tested concentrations while no cytostatic and cytotoxic effects were revealed in vitro. However, when applied in concentrations of 200 mg/kg per os, aqueous extracts of two Satureja species significantly decreased frequency of reticulocytes micronuclei in treated mice against controls. Extracts of S. subspicata and S. horvatii in concentrations of 0.2 mg/mL, regardless of solvent used, downregulated pro-apoptotic and upregulated anti-apoptotic genes, showing anti-apoptotic activity. Our results indicate that the registered anti-genotoxic and anti-apoptotic activity is most likely related to the high level of phenolic acids (particularly rosmarinic and caffeic) in the tested extracts.

scholarly journals Additional evidence for a proform to tropoelastin from chick aorta

1979 ◽  
Vol 177 (2) ◽  
pp. 559-567 ◽  
Author(s):  
C S Heng-Khoo ◽  
R B Rucker ◽  
K W Buckingham
Keyword(s):  
Basic Protein ◽  
Cross Linking ◽  
Protein Subunit ◽  
Deficient Diet ◽  
Culture In Vitro ◽  
One Step

Evidence is presented for the presence of precursor to tropoelastin in chick arterial extracts. The precursor is approx. 100 000 daltons in size. It is suggested to be a precursor to tropoelastin (72 000 daltons). This protein may be observed in culture in vitro if appropriate precautions are taken to inhibit proteolysis. Once synthesized, it appears to be converted into tropoelastin within 10–20 min. The protein may also be detected in vivo. When 1-day-old cockerels were fed on a copper-deficient diet (less than 1 p.p.m. to inhibit cross-linking) containing epsilon-aminohexanoic acid (0.2%) to retard proteolysis and then injected wiht [3H]valine, extraction of arterial proteins 12h after injection resulted in detection of two major peaks of [3H]valine-labelled protein with pI values of pH 7.0 and 5.0 respectively. The protein that focused at pH 7.0 was estimated to be about 100 000 daltons in size and could be shown to be converted into a more basic protein with the properties of tropoelastin. It is speculated that the protein with pI 5.0 may be yet another extension peptide. The data appear to be in keeping with similar observations by ourselves and others that a proform of tropoelastin exists, and, in at least one step before conversion into tropoelastin, exists as a 100 000-dalton protein subunit.

scholarly journals Antigenicity of the infected-erythrocyte and merozoite surfaces in Falciparum malaria.

1979 ◽  
Vol 150 (5) ◽  
pp. 1241-1254 ◽  
Author(s):  
S G Langreth ◽  
R T Reese
Keyword(s):  
Plasmodium Falciparum ◽  
Falciparum Malaria ◽  
Infected Erythrocyte ◽  
Falciparum Infection ◽  
Human Erythrocytes ◽  
Cross Linking ◽  
Common Antigens

The antigenicity of altered structures induced by Plasmodium falciparum in the membranes of infected Aotus monkey and human erythrocytes was examined. Antisera were obtained from monkeys made immune to malaria. Bound antibodies were shown to be localized on the knob protrusions of infected erythrocytes of both human and monkey origin and from both in vitro and in vivo infections. Therefore, P. falciparum infection has produced similar antigenic changes in the erythrocyte surfaces of both man and monkey. Uninfected erythrocytes and all knobless-infected erythrocytes bound no antibody from immune sera. Strains of P. falciparum from widely different geographic areas that were cultured in vitro in human erythrocytes induced structures (knobs) which have common antigenicity. Merozoites were agglutinated by cross-linking of their cell coats when incubated with immune sera. The binding of ferritin-labeled antibody was heavy on the coats of both homologous and heterologous strains of the parasite, indicating that the merozoite surfaces of these strains share common antigens.

scholarly journals Immunological Reaction in TNF-α-Mediated Osteoclast Formation and Bone ResorptionIn VitroandIn Vivo

2013 ◽  
Vol 2013 ◽  
pp. 1-8 ◽  
Author(s):  
Hideki Kitaura ◽  
Keisuke Kimura ◽  
Masahiko Ishida ◽  
Haruka Kohara ◽  
Masako Yoshimatsu ◽  
...  
Keyword(s):  
T Cells ◽  
Bone Metabolism ◽  
Stromal Cells ◽  
Fas Ligand ◽  
Bone Marrow Cells ◽  
Bone Destruction ◽  
Osteoclast Formation ◽  
Bone Diseases

Tumor necrosis factor-α(TNF-α) is a cytokine produced by monocytes, macrophages, and T cells and is induced by pathogens, endotoxins, or related substances. TNF-αmay play a key role in bone metabolism and is important in inflammatory bone diseases such as rheumatoid arthritis. Cells directly involved in osteoclastogenesis include macrophages, which are osteoclast precursor cells, osteoblasts, or stromal cells. These cells express receptor activator of NF-κB ligand (RANKL) to induce osteoclastogenesis, and T cells, which secrete RANKL, promote osteoclastogenesis during inflammation. Elucidating the detailed effects of TNF-αon bone metabolism may enable the identification of therapeutic targets that can efficiently suppress bone destruction in inflammatory bone diseases. TNF-αis considered to act by directly increasing RANK expression in macrophages and by increasing RANKL in stromal cells. Inflammatory cytokines such as interleukin- (IL-) 12, IL-18, and interferon-γ(IFN-γ) strongly inhibit osteoclast formation. IL-12, IL-18, and IFN-γinduce apoptosis in bone marrow cells treated with TNF-α  in vitro, and osteoclastogenesis is inhibited by the interactions of TNF-α-induced Fas and Fas ligand induced by IL-12, IL-18, and IFN-γ. This review describes and discusses the role of cells concerned with osteoclast formation and immunological reactions in TNF-α-mediated osteoclastogenesisin vitroandin vivo.

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