Inflammation is a consequence of the activation of innate immunity and represents an important component of several pathological conditions, including not only the complication of infections but also sterile and autoimmune diseases. An early event in inflammation is represented by the production of proinflammatory cytokines and both their production and action have often been associated to oxidative stress. The redox status of the cell is therefore a key regulator of inflammation and glutathionylation (formation of mixed disulphides between cysteine residues of proteins and glutathione) is considered an important mechanism of this regulation. While most of the studies in the past focused on glutathionylation of intracellular proteins and transcription factors, the main goal of this project was to verify whether glutathionylated proteins are released by inflammatory cells and if these have a biological role. Using redox proteomics, we identified several proteins in the supernatants from Raw 264.7 cells (murine macrophages) stimulated with bacterial lipopolysaccharide (LPS). Among the identified proteins, we focused our attention on Peroxiredoxin 2 (Prx2), an antioxidant enzyme involved in cells protection against oxidative stress by removing H2O2. Released Prx2 was also detected in supernatant from human peripheral blood mononuclear cells (PBMC) and human macrophages. Prx2 levels were also increased in the serum of LPS-treated mice. We could confirm that Prx2 is released in the glutathionylated form. Moreover it was observed that the intracellular level of glutathione affects Prx2 release suggesting a role for glutathionylation in the mechanism of its release. The second part of the project was to verify whether released glutathionylated proteins may act as mediators of inflammation. To this purpose, the possible inflammatory role of released Prx2 was studied. The results showed that extracellular Prx2 induced an increase of TNF-α production in Raw 264.7 cells and in human macrophages. In conclusion, Prx2 is released during inflammation in a redox-dependent manner, in addition to its well-known intracellular role as enzyme, Prx2, in its released form, can also play a role in inflammatory response.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:608306 |
| Date | January 2013 |
| Creators | Salzano, Sonia |
| Publisher | University of Brighton |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | https://research.brighton.ac.uk/en/studentTheses/f28a2a37-9169-4b2a-abe8-ee83c6bfe86f |
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