Trypanosoma cruzi chemical proteomics using immobilized benznidazole

Benznidazole (Bzn) is a nitroimidazole drug currently used as first line treatment against Chagas disease, a neglected tropical disease caused by the flagellated protozoan Trypanosoma cruzi. Although the drug has been used since the late 1960s, its mechanism of action is not fully understood. In an attempt to study Bzn mode of action, a structurally modified derivative of the drug was synthesized and immobilized into a solid matrix. This allowed enrichment of T. cruzi proteins capable of binding immobilized Bzn, which were subsequently analysed by mass spectrometry. The proteins identified as specific non-covalent Bzn interactors were a homologue of the bacterial YjeF proteins, a Sec23A orthologue and the aldo–ketoreductase family member TcAKR. TcAKR is closely related to other enzymes previously associated with Bzn reductive activation such as NTRI and TcOYE. Thus, our untargeted search for Bzn binding partners allowed us to encounter proteins that could be related to drug reductive activation and/or resistance mechanisms.Fil: Trochine, Andrea. Instituto Pasteur de Montevideo. Unidad de Biologia Molecular; Uruguay. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Patagonia Norte. Instituto de Investigación en Biodiversidad y Medioambiente; ArgentinaFil: Alvarez, Guzmán. Universidad de la República. Facultad de Ciencias; UruguayFil: Corre, Sandra. Instituto Pasteur de Montevideo. Unidad de Biologia Molecular; UruguayFil: Faral Tello, Paula. Instituto Pasteur de Montevideo. Unidad de Biologia Molecular; UruguayFil: Durán, Rosario. Instituto Pasteur de Montevideo; UruguayFil: Batthyany, Carlos I.. Instituto Pasteur de Montevideo; Uruguay. Instituto de Investigaciones Biologicas "Clemente Estable"; UruguayFil: Cerecetto, Hugo. Universidad de la República. Facultad de Ciencias; Uruguay. Instituto de Investigaciones Biologicas "Clemente Estable"; UruguayFil: Gonzalez, Mercedes. Universidad de la República. Facultad de Ciencias; UruguayFil: Robello, Carlos. Instituto Pasteur de Montevideo. Unidad de Biologia Molecular; Uruguay. Universidad de la Republica; Urugua

Macrophage activation induces formation of the anti-inflammatory lipid cholesteryl-nitrolinoleate

Nitroalkene derivatives of fatty acids act as adaptive, anti-inflammatory signalling mediators, based on their high-affinity PPARγ (peroxisome-proliferator-activated receptor γ) ligand activity and electrophilic reactivity with proteins, including transcription factors. Although free or esterified lipid nitroalkene derivatives have been detected in human plasma and urine, their generation by inflammatory stimuli has not been reported. In the present study, we show increased nitration of cholesteryl-linoleate by activated murine J774.1 macrophages, yielding the mononitrated nitroalkene CLNO2 (cholesteryl-nitrolinoleate). CLNO2 levels were found to increase ∼20-fold 24 h after macrophage activation with Escherichia coli lipopolysaccharide plus interferon-γ; this response was concurrent with an increase in the expression of NOS2 (inducible nitric oxide synthase) and was inhibited by the •NO (nitric oxide) inhibitor L-NAME (NG-nitro-L-arginine methyl ester). Macrophage (J774.1 and bone-marrow-derived cells) inflammatory responses were suppressed when activated in the presence of CLNO2 or LNO2 (nitrolinoleate). This included: (i) inhibition of NOS2 expression and cytokine secretion through PPARγ and •NO-independent mechanisms; (ii) induction of haem oxygenase-1 expression; and (iii) inhibition of NF-κB (nuclear factor κB) activation. Overall, these results suggest that lipid nitration occurs as part of the response of macrophages to inflammatory stimuli involving NOS2 induction and that these by-products of nitro-oxidative reactions may act as novel adaptive down-regulators of inflammatory responses

Macrophage activation induces formation of the anti-inflammatory lipid cholesteryl-nitrolinoleate

Nitroalkene derivatives of fatty acids act as adaptive, anti-inflammatory signalling mediators, based on their high-affinity PPARγ (peroxisome-proliferator-activated receptor γ) ligand activity and electrophilic reactivity with proteins, including transcription factors. Although free or esterified lipid nitroalkene derivatives have been detected in human plasma and urine, their generation by inflammatory stimuli has not been reported. In the present study, we show increased nitration of cholesteryl-linoleate by activated murine J774.1 macrophages, yielding the mononitrated nitroalkene CLNO2 (cholesteryl-nitrolinoleate). CLNO2 levels were found to increase ∼20-fold 24 h after macrophage activation with Escherichia coli lipopolysaccharide plus interferon-γ; this response was concurrent with an increase in the expression of NOS2 (inducible nitric oxide synthase) and was inhibited by the •NO (nitric oxide) inhibitor L-NAME (NG-nitro-L-arginine methyl ester). Macrophage (J774.1 and bone-marrow-derived cells) inflammatory responses were suppressed when activated in the presence of CLNO2 or LNO2 (nitrolinoleate). This included: (i) inhibition of NOS2 expression and cytokine secretion through PPARγ and •NO-independent mechanisms; (ii) induction of haem oxygenase-1 expression; and (iii) inhibition of NF-κB (nuclear factor κB) activation. Overall, these results suggest that lipid nitration occurs as part of the response of macrophages to inflammatory stimuli involving NOS2 induction and that these by-products of nitro-oxidative reactions may act as novel adaptive down-regulators of inflammatory responses

Conjugated linoleic acid is a preferential substrate for fatty acid nitration

The oxidation and nitration of unsaturated fatty acids by oxides of nitrogen yield electrophilic derivatives that can modulate protein function via post-translational protein modifications. The biological mechanisms accounting for fatty acid nitration and the specific structural characteristics of products remain to be defined. Herein, conjugated linoleic acid (CLA) is identified as the primary endogenous substrate for fatty acid nitration in vitro and in vivo, yielding up to 105 greater extent of nitration products as compared with bis-allylic linoleic acid. Multiple enzymatic and cellular mechanisms account for CLA nitration, including reactions catalyzed by mitochondria, activated macrophages, and gastric acidification. Nitroalkene derivatives of CLA and their metabolites are detected in the plasma of healthy humans and are increased in tissues undergoing episodes of ischemia reperfusion. Dietary CLA and nitrite supplementation in rodents elevates NO2-CLA levels in plasma, urine, and tissues, which in turn induces heme oxygenase-1 (HO-1) expression in the colonic epithelium. These results affirm that metabolic and inflammatory reactions yield electrophilic products that can modulate adaptive cell signaling mechanisms.Fil: Bonacci, Gustavo Roberto. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Córdoba. Centro de Investigaciones en Bioquímica Clínica e Inmunología; Argentina. Univeristy Of Pittsburgh. School Of Medicine. Department Of Pharmacology And Chemical Biology; Estados UnidosFil: Baker, Paul R. S.. Univeristy Of Pittsburgh. School Of Medicine. Department Of Pharmacology And Chemical Biology; Estados UnidosFil: Salvatore, Sonia Rosana. Univeristy Of Pittsburgh. School Of Medicine. Department Of Pharmacology And Chemical Biology; Estados UnidosFil: Shores, Darla. University of Pittsburgh; Estados UnidosFil: Khoo, Nicholas K. H.. Univeristy Of Pittsburgh. School Of Medicine. Department Of Pharmacology And Chemical Biology; Estados UnidosFil: Koenitzer, Jeffrey R.. Univeristy Of Pittsburgh. School Of Medicine. Department Of Pharmacology And Chemical Biology; Estados UnidosFil: Vitturi, Dario A.. Univeristy Of Pittsburgh. School Of Medicine. Department Of Pharmacology And Chemical Biology; Estados UnidosFil: Woodcock, Steven R.. Univeristy Of Pittsburgh. School Of Medicine. Department Of Pharmacology And Chemical Biology; Estados UnidosFil: Golin-Bisello, Franca. Univeristy Of Pittsburgh. School Of Medicine. Department Of Pharmacology And Chemical Biology; Estados UnidosFil: Cole, Marsha P.. Univeristy Of Pittsburgh. School Of Medicine. Department Of Pharmacology And Chemical Biology; Estados UnidosFil: Watkins, Simon. University of Pittsburgh; Estados UnidosFil: St. Croix, Claudette. University of Pittsburgh; Estados UnidosFil: Batthyany, Carlos I.. Instituto Pasteur; Uruguay. Univeristy Of Pittsburgh. School Of Medicine. Department Of Pharmacology And Chemical Biology; Estados UnidosFil: Freeman, Bruce A.. Univeristy Of Pittsburgh. School Of Medicine. Department Of Pharmacology And Chemical Biology; Estados UnidosFil: Schopfer, Francisco J.. Univeristy Of Pittsburgh. School Of Medicine. Department Of Pharmacology And Chemical Biology; Estados Unido

Electrophilic Fatty Acids Regulate Matrix Metalloproteinase Activity and Expression*

Nitro-fatty acids (NO2-FA) are electrophilic signaling mediators formed by reactions of nitric oxide and nitrite. NO2-FA exert anti-inflammatory signaling actions through post-translational protein modifications. We report that nitro-oleic acid (OA-NO2) stimulates proMMP-7 and proMMP-9 proteolytic activity via adduction of the conserved cysteine switch domain thiolate. Biotin-labeled OA-NO2 showed this adduction occurs preferentially with latent forms of MMP, confirming a role for thiol alkylation by OA-NO2 in MMP activation. In addition to regulating pro-MMP activation, MMP expression was modulated by OA-NO2 via activation of peroxisome proliferator-activated receptor-γ. MMP-9 transcription was decreased in phorbol 12-myristate 13-acetate-stimulated THP-1 macrophages to an extent similar to that induced by the peroxisome proliferator-activated receptor-γ agonist Rosiglitazone. This was affirmed using a murine model of atherosclerosis, ApoE−/− mice, where in vivo OA-NO2 administration suppressed MMP expression in atherosclerotic lesions. These findings reveal that electrophilic fatty acid derivatives can serve as effectors during inflammation, first by activating pro-MMP proteolytic activity via alkylation of the cysteine switch domain, and then by transcriptionally inhibiting MMP expression, thereby limiting the further progression of inflammatory processes

Covalent Peroxisome Proliferator-activated Receptor γ Adduction by Nitro-fatty Acids: SELECTIVE LIGAND ACTIVITY AND ANTI-DIABETIC SIGNALING ACTIONS*

The peroxisome proliferator-activated receptor-γ (PPARγ) binds diverse ligands to transcriptionally regulate metabolism and inflammation. Activators of PPARγ include lipids and anti-hyperglycemic drugs such as thiazolidinediones (TZDs). Recently, TZDs have raised concern after being linked with increased risk of peripheral edema, weight gain, and adverse cardiovascular events. Most reported endogenous PPARγ ligands are intermediates of lipid metabolism and oxidation that bind PPARγ with very low affinity. In contrast, nitro derivatives of unsaturated fatty acids (NO2-FA) are endogenous products of nitric oxide (•NO) and nitrite (NO2−)-mediated redox reactions that activate PPARγ at nanomolar concentrations. We report that NO2-FA act as partial agonists of PPARγ and covalently bind PPARγ at Cys-285 via Michael addition. NO2-FA show selective PPARγ modulator characteristics by inducing coregulator protein interactions, PPARγ-dependent expression of key target genes, and lipid accumulation is distinctively different from responses induced by the TZD rosiglitazone. Administration of this class of signaling mediators to ob/ob mice revealed that NO2-FA lower insulin and glucose levels without inducing adverse side effects such as the increased weight gain induced by TZDs

PD-1/PD-L1 blockade abrogates a dysfunctional innate-adaptive immune axis in critical β-coronavirus disease

Severe COVID-19 is associated with hyperinflammation and weak T cell responses against SARS-CoV-2. However, the links between those processes remain partially characterized. Moreover, whether and how therapeutically manipulating T cells may benefit patients are unknown. Our genetic and pharmacological evidence demonstrates that the ion channel TMEM176B inhibited inflammasome activation triggered by SARS-CoV-2 and SARS-CoV-2- related murine β-coronavirus. Tmem176b-/- mice infected with murine β-coronavirus developed inflammasome-dependent T cell dysfunction and critical disease, which was controlled by modulating dysfunctional T cells with PD-1 blockers. In critical COVID-19, inflammasome activation correlated with dysfunctional T cells and low monocytic TMEM176B expression, whereas PD-L1 blockade rescued T cell functionality. Here, we mechanistically link T cell dysfunction and inflammation, supporting a cancer immunotherapy to reinforce T cell immunity in critical β-coronavirus disease.Fil: Duhalde Vega, Maite. Institut Pasteur de Montevideo; Uruguay. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Instituto de Química y Físico-Química Biológicas "Prof. Alejandro C. Paladini". Universidad de Buenos Aires. Facultad de Farmacia y Bioquímica. Instituto de Química y Físico-Química Biológicas; ArgentinaFil: Olivera, Daniela. Institut Pasteur de Montevideo; Uruguay. Universidad de la República; UruguayFil: Davanzo, Gustavo Gastão. Universidade Estadual de Campinas; BrasilFil: Bertullo, Mauricio. Immunoregulation And Inflammation Lab; UruguayFil: Noya, Verónica. Sanatorio Americano; UruguayFil: de Souza, Gabriela Fabiano. Universidade Estadual de Campinas; BrasilFil: Muraro, Stéfanie Primon. Universidade Estadual de Campinas; BrasilFil: Castro, Icaro. Hospital Israelita Albert Einstein; BrasilFil: Arévalo, Ana Paula. Institut Pasteur de Montevideo; UruguayFil: Crispo, Martina. Institut Pasteur de Montevideo; UruguayFil: Galliussi, Germán. Institut Pasteur de Montevideo; UruguayFil: Russo, Sofía. Institut Pasteur de Montevideo; Uruguay. Universidad de la República; UruguayFil: Charbonnier, David. Institut Pasteur de Montevideo; UruguayFil: Rammauro, Florencia. Institut Pasteur de Montevideo; Uruguay. Universidad de la República; UruguayFil: Jeldres, Mathías. Institut Pasteur de Montevideo; Uruguay. Universidad de la República; UruguayFil: Alamón, Catalina. Institut Pasteur de Montevideo; UruguayFil: Varela, Valentina. Institut Pasteur de Montevideo; UruguayFil: Batthyany, Carlos. Institut Pasteur de Montevideo; UruguayFil: Bollati Fogolín, Mariela. Institut Pasteur de Montevideo; UruguayFil: Oppezzo, Pablo. Institut Pasteur de Montevideo; UruguayFil: Pritsch, Otto. Institut Pasteur de Montevideo; Uruguay. Universidad de la República; UruguayFil: Proença Módena, José Luiz. Universidade Estadual de Campinas; BrasilFil: Nakaya, Helder I.. Hospital Israelita Albert Einstein; BrasilFil: Trias, Emiliano. Institut Pasteur de Montevideo; UruguayFil: Barbeito, Luis. Institut Pasteur de Montevideo; UruguayFil: Anegon, Ignacio. Center For Research In Transplantation And Immunology; FranciaFil: Cuturi, María Cristina. Center For Research In Transplantation And Immunology; FranciaFil: Moraes Vieira, Pedro. Universidade Estadual de Campinas; BrasilFil: Segovia, Mercedes. Institut Pasteur de Montevideo; Uruguay. Universidad de la República; UruguayFil: Hill, Marcelo. Universidad de la República; Uruguay. Institut Pasteur de Montevideo; Urugua