Innate Gender-based Proclivity in Response to Cytotoxicity and Programmed Cell Death Pathway

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Strategies for Discovery of Small Molecule Radiation Protectors and Radiation Mitigators

Mitochondrial targeted radiation damage protectors (delivered prior to irradiation) and mitigators (delivered after irradiation, but before the appearance of symptoms associated with radiation syndrome) have been a recent focus in drug discovery for (1) normal tissue radiation protection during fractionated radiotherapy, and (2) radiation terrorism counter measures. Several categories of such molecules have been discovered: nitroxide-linked hybrid molecules, including GS-nitroxide, GS-nitric oxide synthase inhibitors, p53/mdm2/mdm4 inhibitors, and pharmaceutical agents including inhibitors of the phosphoinositide-3-kinase pathway and the anti-seizure medicine, carbamazepine. Evaluation of potential new radiation dose modifying molecules to protect normal tissue includes: clonogenic radiation survival curves, assays for apoptosis and DNA repair, and irradiation-induced depletion of antioxidant stores. Studies of organ specific radioprotection and in total body irradiation-induced hematopoietic syndrome in the mouse model for protection/mitigation facilitate rational means by which to move candidate small molecule drugs along the drug discovery pipeline into clinical development

Detection of PHLPP1α/β in Human and Mouse Brain by Different Anti-PHLPP1 Antibodies

Pleckstrin homology domain and leucine rich repeat protein phosphatase 1 (PHLPP1) is a member of the serine/threonine family of phosphatases. It has been studied in organs including brain, heart, pancreas, adipose, breast, and prostate. Human PHLPP1 encodes two splice variants - PHLPP1α (~140-150 kDa) and PHLPP1β (~180-190 kDa). Commercial antibodies are widely used to characterize PHLPP1 proteins in cells/tissues. Here we validate five different antibodies to detect PHLPP1α/β by Western blot using PHLPP1 WT/KO mice. All antibodies recognize PHLPP1β in brain. Only a single antibody (Cosmo Bio Co) detects PHLPP1α (~145-150 kDa). The other four antibodies detect a non-specific signal at ~150 kDa as evidenced by its abundance in PHLPP1 KO tissues. Results suggest Cosmo antibody is a better reagent to detect PHLPP1α by Western blot. In contrast, we found it unsuitable for immunofluorescence applications in brain. Our findings caution interpretation of the ~150 kDa band detected by some PHLPP1 antibodies in rodent and human tissues. Results also recapitulate the importance of including molecular weight standards in Western blot data to simplify retrospective analysis

C-ferroptosis is an iron-dependent form of regulated cell death in cyanobacteria

Ferroptosis is an oxidative and iron-dependent form of regulated cell death (RCD) recently described in eukaryotic organisms like animals, plants, and parasites. Here, we report that a similar process takes place in the photosynthetic prokaryote Synechocystis sp. PCC 6803 in response to heat stress. After a heat shock, Synechocystis sp. PCC 6803 cells undergo a cell death pathway that can be suppressed by the canonical ferroptosis inhibitors, CPX, vitamin E, Fer-1, liproxstatin-1, glutathione (GSH), or ascorbic acid (AsA). Moreover, as described for eukaryotic ferroptosis, this pathway is characterized by an early depletion of the antioxidants GSH and AsA, and by lipid peroxidation. These results indicate that all of the hallmarks described for eukaryotic ferroptosis are conserved in photosynthetic prokaryotes and suggest that ferroptosis might be an ancient cell death program.Fil: Aguilera, Anabella. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; ArgentinaFil: Berdun, Federico Juan. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; ArgentinaFil: Bartoli, Carlos Guillermo. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Fisiología Vegetal. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Fisiología Vegetal; ArgentinaFil: Steelheart Molina, Maria Charlotte. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Fisiología Vegetal. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Fisiología Vegetal; ArgentinaFil: Alegre, Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - La Plata. Instituto de Fisiología Vegetal. Universidad Nacional de La Plata. Facultad de Ciencias Naturales y Museo. Instituto de Fisiología Vegetal; ArgentinaFil: Bayir, Hülya. University of Pittsburgh; Estados UnidosFil: Tyurina, Yulia Y.. University of Pittsburgh; Estados UnidosFil: Kagan, Valerian E.. University of Pittsburgh; Estados UnidosFil: Salerno, Graciela Lidia. Fundación para Investigaciones Biológicas Aplicadas; ArgentinaFil: Pagnussat, Gabriela Carolina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; ArgentinaFil: Martin, María Victoria. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones en Biodiversidad y Biotecnología; Argentin

Phosphatidylserine Targets Single-Walled Carbon Nanotubes to Professional Phagocytes In Vitro and In Vivo

Broad applications of single-walled carbon nanotubes (SWCNT) dictate the necessity to better understand their health effects. Poor recognition of non-functionalized SWCNT by phagocytes is prohibitive towards controlling their biological action. We report that SWCNT coating with a phospholipid “eat-me” signal, phosphatidylserine (PS), makes them recognizable in vitro by different phagocytic cells - murine RAW264.7 macrophages, primary monocyte-derived human macrophages, dendritic cells, and rat brain microglia. Macrophage uptake of PS-coated nanotubes was suppressed by the PS-binding protein, Annexin V, and endocytosis inhibitors, and changed the pattern of pro- and anti-inflammatory cytokine secretion. Loading of PS-coated SWCNT with pro-apoptotic cargo (cytochrome c) allowed for the targeted killing of RAW264.7 macrophages. In vivo aspiration of PS-coated SWCNT stimulated their uptake by lung alveolar macrophages in mice. Thus, PS-coating can be utilized for targeted delivery of SWCNT with specified cargoes into professional phagocytes, hence for therapeutic regulation of specific populations of immune-competent cells

Radioprotection by short-term oxidative preconditioning: Role of manganese superoxide dismutase

AbstractManganese superoxide dismutase (MnSOD) is vital to the protection of mitochondria and cells against oxidative stress. Earlier, we demonstrated that catalytically active homo-tetramer of MnSOD can be stabilized by oxidative cross-linking. Here we report that this effect may be translated into increased radioresistance of mouse embryonic cells (MECs) by pre-exposure to oxidative stress. Pre-treatment of MECs with antimycin A, rotenone or H2O2 increased their survival after irradiation. Using MnSOD siRNA, we show that MECs with decreased MnSOD levels displayed a lowered ability to preconditioning. Thus oxidative preconditioning may be used for targeted regulation of MnSOD.Structured summaryMINT-7288408: MnSOD (uniprotkb:P04179) and MnSOD (uniprotkb:P04179) physically interact (MI:0915) by zymography (MI:0512

Regulation of lipid peroxidation and ferroptosis in diverse species

Lipid peroxidation is the process by which oxygen combines with lipids to generate lipid hydroperoxides via intermediate formation of peroxyl radicals. Vitamin E and coenzyme Q10 react with peroxyl radicals to yield peroxides, and then these oxidized lipid species can be detoxified by glutathione and glutathione peroxidase 4 (GPX4) and other components of the cellular antioxidant defense network. Ferroptosis is a form of regulated nonapoptotic cell death involving overwhelming iron-dependent lipid peroxidation. Here, we review the functions and regulation of lipid peroxidation, ferroptosis, and the antioxidant network in diverse species, including humans, other mammals and vertebrates, plants, invertebrates, yeast, bacteria, and archaea. We also discuss the potential evolutionary roles of lipid peroxidation and ferroptosis.Fil: Conrad, Marcus. Helmholtz Center Munich German Research Center For Environmental Health;Fil: Kagan, Valerian E.. University of Pittsburgh at Johnstown; Estados Unidos. University of Pittsburgh; Estados Unidos. Sechenov First Moscow State Medical University;Fil: Bayir, Hülya. University of Pittsburgh; Estados Unidos. University of Pittsburgh at Johnstown; Estados UnidosFil: Pagnussat, Gabriela Carolina. Universidad Nacional de Mar del Plata; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Mar del Plata. Instituto de Investigaciones Biológicas. Universidad Nacional de Mar del Plata. Facultad de Ciencias Exactas y Naturales. Instituto de Investigaciones Biológicas; ArgentinaFil: Head, Brian. Linus Pauling Institute; . State University of Oregon; Estados UnidosFil: Traber, Maret G.. Linus Pauling Institute; . State University of Oregon; Estados UnidosFil: Stockwell, Brent R.. Columbia University; Estados Unido