Inactivación oxidativa de la glutamina sintetasa humana: efectos estructurales y aspectos cuantitativos durante la pérdida de función por daño oxidativo

CSIC: 2017, Iniciación Modalidad 2, ID 15

Multiple oxidative post-translational modifications of human glutamine synthetase mediate peroxynitrite-dependent enzyme inactivation and aggregation

Funding Information: This work was supported by grants of Universidad de la República (CSIC_2018 and EI_2020) to R. R., Universidad de la República (CSIC Iniciación_2017_ID_159) to N. C., Alexander von Humboldt Foundation (AvHF) to T. G. and R. R., the Novo Nordisk Foundation ( NNF13OC0004294 and NNF20SA0064214 ) to M. J. D., and PICT 2018-0795 from Agencia I+d+i Argentina , University of Buenos Aires (grant 20020120300025BA ), and CONICET (grant 11220150100303CO ) to D. E. N. C. was partially supported by a fellowship from Comisión Académica de Posgrado (CAP), Universidad de la República , Uruguay. Additional funding was obtained from Programa de Desarrollo de las Ciencias Básicas (PEDECIBA, Uruguay), Agencia Nacional de Investigación e Innovación (ANII-SNI, Uruguay), EU-LAC Health (EULACH16/T01-0131), and Programa de Alimentos y Salud Humana (PAyS, Uruguay). Funding Information: The authors would like to thank Dr Tobias Karlberg and Dr Susanne Gräslund from the Karolinska Institutet - Structural Genomics Consortium for providing the HsGS plasmid (Construct ID GLULA-c004). We also thank Dr Verónica Tórtora for her major aid within the initial steps of the transformation and HsGS expression experiments. N. C. D. E. P. H. T. G. M. J. D. S. B. and R. R. conceptualization; N. C. Mauricio Mastrogiovanni, Michele Mariotti, F. M. I. and P. H. methodology; N. C. Mauricio Mastrogiovanni, Michele Mariotti, and F. M. I. investigation; N. C. writing–original draft; M. J. D. S. B. and R. R. writing–review and editing; R. R. supervision. This work was supported by grants of Universidad de la República (CSIC_2018 and EI_2020) to R. R. Universidad de la República (CSIC Iniciación_2017_ID_159) to N. C. Alexander von Humboldt Foundation (AvHF) to T. G. and R. R. the Novo Nordisk Foundation (NNF13OC0004294 and NNF20SA0064214) to M. J. D. and PICT 2018-0795 from Agencia I+d+i Argentina, University of Buenos Aires (grant 20020120300025BA), and CONICET (grant 11220150100303CO) to D. E. N. C. was partially supported by a fellowship from Comisión Académica de Posgrado (CAP), Universidad de la República, Uruguay. Additional funding was obtained from Programa de Desarrollo de las Ciencias Básicas (PEDECIBA, Uruguay), Agencia Nacional de Investigación e Innovación (ANII-SNI, Uruguay), EU-LAC Health (EULACH16/T01-0131), and Programa de Alimentos y Salud Humana (PAyS, Uruguay). Publisher Copyright: © 2023 The AuthorsGlutamine synthetase (GS), which catalyzes the ATP-dependent synthesis of L-glutamine from L-glutamate and ammonia, is a ubiquitous and conserved enzyme that plays a pivotal role in nitrogen metabolism across all life domains. In vertebrates, GS is highly expressed in astrocytes, where its activity sustains the glutamate-glutamine cycle at glutamatergic synapses and is thus essential for maintaining brain homeostasis. In fact, decreased GS levels or activity have been associated with neurodegenerative diseases, with these alterations attributed to oxidative post-translational modifications of the protein, in particular tyrosine nitration. In this study, we expressed and purified human GS (HsGS) and performed an in-depth analysis of its oxidative inactivation by peroxynitrite (ONOO−) in vitro. We found that ONOO− exposure led to a dose-dependent loss of HsGS activity, the oxidation of cysteine, methionine, and tyrosine residues and also the nitration of tryptophan and tyrosine residues. Peptide mapping by LC-MS/MS through combined H216O/H218O trypsin digestion identified up to 10 tyrosine nitration sites and five types of dityrosine cross-links; these modifications were further scrutinized by structural analysis. Tyrosine residues 171, 185, 269, 283, and 336 were the main nitration targets; however, tyrosine-to-phenylalanine HsGS mutants revealed that their sole nitration was not responsible for enzyme inactivation. In addition, we observed that ONOO− induced HsGS aggregation and activity loss. Thiol oxidation was a key modification to elicit aggregation, as it was also induced by hydrogen peroxide treatment. Taken together, our results indicate that multiple oxidative events at various sites are responsible for the inactivation and aggregation of human GS.publishersversionpublishe

3-Nitrotyrosine and related derivatives in proteins: precursors, radical intermediates and impact in function

Oxidative post-translational modification of proteins by molecular oxygen (O2)- and nitric oxide (•NO)-derived reactive species is a usual process that occurs in mammalian tissues under both physiological and pathological conditions and can exert either regulatory or cytotoxic effects. Although the side chain of several amino acids is prone to experience oxidative modifications, tyrosine residues are one of the preferred targets of one-electron oxidants, given the ability of their phenolic side chain to undergo reversible one-electron oxidation to the relatively stable tyrosyl radical. Naturally occurring as reversible catalytic intermediates at the active site of a variety of enzymes, tyrosyl radicals can also lead to the formation of several stable oxidative products through radical–radical reactions, as is the case of 3-nitrotyrosine (NO2Tyr). The formation of NO2Tyr mainly occurs through the fast reaction between the tyrosyl radical and nitrogen dioxide (•NO2). One of the key endogenous nitrating agents is peroxynitrite (ONOO−), the product of the reaction of superoxide radical (O2•−) with •NO, but ONOO−-independent mechanisms of nitration have been also disclosed. This chemical modification notably affects the physicochemical properties of tyrosine residues and because of this, it can have a remarkable impact on protein structure and function, both in vitro and in vivo. Although low amounts of NO2Tyr are detected under basal conditions, significantly increased levels are found at pathological states related with an overproduction of reactive species, such as cardiovascular and neurodegenerative diseases, inflammation and aging. While NO2Tyr is a well-established stable oxidative stress biomarker and a good predictor of disease progression, its role as a pathogenic mediator has been laboriously defined for just a small number of nitrated proteins and awaits further studies.Fil: Campolo, Nicolás. Universidad de la República; UruguayFil: Issoglio, Federico Matías. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química Biológica de la Facultad de Ciencias Exactas y Naturales; ArgentinaFil: Estrin, Dario Ariel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Química, Física de los Materiales, Medioambiente y Energía. Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Química, Física de los Materiales, Medioambiente y Energía; ArgentinaFil: Bartesaghi Hierro, Silvina María. Universidad de la República; UruguayFil: Radi, Rafael. Universidad de la República; Urugua

The Effect of Fat Intake with Increased Omega-6-to-Omega-3 Polyunsaturated Fatty Acid Ratio in Animal Models of Early and Late Alzheimer’s Disease-like Pathogenesis

This work aims to clarify the effect of dietary polyunsaturated fatty acid (PUFA) intake on the adult brain affected by amyloid pathology. McGill-R-Thy1-APP transgenic (Tg) rat and 5xFAD Tg mouse models that represent earlier or later disease stages were employed. The animals were exposed to a control diet (CD) or an HFD based on corn oil, from young (rats) or adult (mice) ages for 24 or 10 weeks, respectively. In rats and mice, the HFD impaired reference memory in wild-type (WT) animals but did not worsen it in Tg, did not cause obesity, and did not increase triglycerides or glucose levels. Conversely, the HFD promoted stronger microglial activation in Tg vs. WT rats but had no effect on cerebral amyloid deposition. IFN-γ, IL-1β, and IL-6 plasma levels were increased in Tg rats, regardless of diet, while CXCL1 chemokine levels were increased in HFD-fed mice, regardless of genotype. Hippocampal 3-nitrotyrosine levels tended to increase in HFD-fed Tg rats but not in mice. Overall, an HFD with an elevated omega-6-to-omega-3 ratio as compared to the CD (25:1 vs. 8.4:1) did not aggravate the outcome of AD regardless of the stage of amyloid pathology, suggesting that many neurobiological processes relevant to AD are not directly dependent on PUFA intake.Fil: Galeano, Pablo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: de Ceglia, Marialuisa. Hospital Universitario Regional de Málaga; EspañaFil: Mastrogiovanni, Mauricio. Universidad de la República; UruguayFil: Campanelli, Lorenzo. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Medina Vera, Dina. Hospital Universitario Regional de Málaga; EspañaFil: Campolo, Nicolás. Universidad de la República; UruguayFil: Novack, Gisela Vanina. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Rosell Valle, Cristina. Hospital Universitario Regional de Málaga; EspañaFil: Suarez, Juan. Universidad de Málaga; EspañaFil: Aicardo, Adrian. Universidad de la República; UruguayFil: Campuzano, Karen Soledad. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Castaño, Eduardo Miguel. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; ArgentinaFil: Do Carmo, Sonia. McGill University; CanadáFil: Cuello, A. Claudio. McGill University; CanadáFil: Bartesaghi Hierro, Silvina María. Universidad de la República; UruguayFil: Radi, Rafael. Universidad de la República; UruguayFil: Rodríguez de Fonseca, Fernando. Hospital Universitario Regional de Málaga; EspañaFil: Morelli, Laura. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Parque Centenario. Instituto de Investigaciones Bioquímicas de Buenos Aires. Fundación Instituto Leloir. Instituto de Investigaciones Bioquímicas de Buenos Aires; Argentin