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Published on: July 28, 2016
Myeloperoxidase: A new player in autoimmunity
Anna Strzepa1, Kirkwood A Pritchard2, Bonnie N Dittel3
1Blood Research Institute, BloodCenter of Wisconsin, Milwaukee, WI, United States; Department of Medical Biology, Faculty of Health Sciences, Jagiellonian University Medical College, ul. Kopernika 7, 31-034 Krakow, Poland.
Abstract:
Myeloperoxidase (MPO) is the most toxic enzyme found in the azurophilic granules of neutrophils. MPO utilizes H2O2 to generate hypochlorous acid (HClO) and other reactive moieties, which kill pathogens during infections. In contrast, in the setting of sterile inflammation, MPO and MPO-derived oxidants are thought to be pathogenic, promoting inflammation and causing tissue damage. In contrast, evidence also exists that MPO can limit the extent of immune responses. Elevated MPO levels and activity are observed in a number of autoimmune diseases including in the central nervous system (CNS) of multiple sclerosis (MS) and the joints of rheumatoid arthritis (RA) patients. A pathogenic role for MPO in driving autoimmune inflammation was demonstrated using mouse models. Mechanisms whereby MPO is thought to contribute to disease pathogenesis include tuning of adaptive immune responses and/or the induction of vascular permeability.
Insights
Myeloperoxidase (MPO) is a neutrophil enzyme that can both fight infection and promote autoimmune diseases like multiple sclerosis and rheumatoid arthritis. Research suggests MPO plays a pathogenic role in autoimmune inflammation.
Area of Science:
- Biochemistry
- Immunology
- Pathology
Background:
- Myeloperoxidase (MPO) is a neutrophil enzyme crucial for pathogen killing via reactive oxidants.
- While vital in infection, MPO and its byproducts are implicated in sterile inflammation and tissue damage.
- Elevated MPO is observed in autoimmune diseases such as multiple sclerosis (MS) and rheumatoid arthritis (RA).
Purpose of the Study:
- To investigate the dual role of MPO in health and autoimmune disease.
- To elucidate the mechanisms by which MPO contributes to autoimmune pathogenesis.
Main Methods:
- Utilized mouse models to demonstrate the pathogenic role of MPO.
- Analyzed MPO activity and levels in autoimmune disease contexts.
Main Results:
- Demonstrated a pathogenic role for MPO in driving autoimmune inflammation in experimental models.
- Identified potential mechanisms including modulation of adaptive immunity and vascular permeability.
Conclusions:
- MPO exhibits a complex role, acting as both a defense enzyme and a driver of autoimmune pathology.
- Understanding MPO's mechanisms is critical for developing targeted therapies for autoimmune diseases like MS and RA.
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