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The role of urate hydroperoxide in macrophage polarization

Grant number: 19/26473-9
Support type:Scholarships in Brazil - Doctorate (Direct)
Effective date (Start): February 01, 2020
Effective date (End): January 31, 2024
Field of knowledge:Biological Sciences - Biochemistry - Metabolism and Bioenergetics
Principal researcher:Flavia Carla Meotti
Grantee:Beatriz Pereira da Silva
Home Institution: Instituto de Química (IQ). Universidade de São Paulo (USP). São Paulo , SP, Brazil
Associated research grant:18/14898-2 - Investigations of the redox processes in inflammatory response and associated pathologies, AP.JP2

Abstract

Previous studies from our group demonstrated that urate hydroperoxide efficiently targets the hydrogen peroxide detoxifying protein peroxiredoxin and these thiol-peroxidases are likely the main target to urate hydroperoxide in the cytosol. After oxidation some peroxiredoxins can transfer their oxidizing equivalents to another signaling protein through thiol-disulfide exchange reactions and this seems to be relevant in redox signaling. Peroxiredoxin 2 forms a redox relay with STAT3 (Signal Transducer and Activator of Transcription 3), inhibiting STAT3 migration to the nucleus in HeLa cells, whereas peroxiredoxin 1 can transfer their oxidizing equivalents to the ASK1 (Apoptosis-regulating kinase-1 signaling), resulting in the phosphorylation of p38 and activation of apoptosis. We found that macrophage peroxiredoxin 1 and peroxiredoxin 2 were oxidized 10 min after incubation with urate hydroperoxide (FAPESP 2013/02195-3) and we wondered whether peroxiredoxins would deliver their oxidant equivalents to STAT3 and inhibit this transcription factor in these macrophages. The inhibition of STAT3 migration to the nucleus would favor macrophage polarization to M1 (pro-inflammatory) rather than M2 (anti-inflammatory) subtype, supporting a pro-inflammatory environment. This hypothesis supports a pro-inflammatory role for urate hydroperoxide by modulating macrophage polarization and could infer, at least in part, a causal role for uric acid in atherogenesis. Beside the M1 and M2 subtype of macrophages, a third type of polarization has been recently purposed. This refers to the Mox polarization pattern, which is caused by pro-oxidant agents, including oxidized phospholipids and nytrosilated fatty acids. This subtype is characterized by an increase in Nrf2 (Nuclear erythroid 2-related fator 2) transcription factor and by a dysfunctional phagocytic capacity. Taking this evidence into account, the activities in this PhD project include the identification of proteins that co-immunoprecipitate with peroxiredoxin 2. We will also look for STAT3 heterodimerization with peroxiredoxin 2 after incubation of human macrophages with urate hydroperoxide, hydrogen peroxide and uric acid. Macrophages polarization will be analyzed by flow cytometry or ELISA immunoassay to detect the expression of specific proteins and cytokines: CD36 and CD40 membrane receptors and cytokines IL-1², TNF-± and the transcription factor NF-k² in M1 subpopulation; CD163 and CD206 in M2 subpopulation; heme-oxigenase-1, sulforedoxin-1 and Nrf2 in Mox subpopulation. All these analyses will also be done in macrophage co-cultured with stimulated neutrophils in presence and absence of uric acid, to verify macrophage redox signaling and polarization during the oxidative burst. (AU)

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Scientific publications
(References retrieved automatically from Web of Science and SciELO through information on FAPESP grants and their corresponding numbers as mentioned in the publications by the authors)
ROCHA, LEONARDO SILVA; DA SILVA, BEATRIZ PEREIRA; CORREIA, THIAGO M. L.; DA SILVA, RAILMARA PEREIRA; MEIRELES, DIOGO DE ABREU; PEREIRA, RAFAEL; SOARES NETTO, LUIS EDUARDO; MEOTTI, FLAVIA CARLA; QUEIROZ, RAPHAEL FERREIRA. Peroxiredoxin AhpC1 protects Pseudomonas aeruginosa against the inflammatory oxidative burst and confers virulence. REDOX BIOLOGY, v. 46, . (15/21563-9, 13/07937-8, 15/10411-3, 18/14898-2, 19/26473-9)

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