51. N -chlorination mediates protective and immunomodulatory effects of oxidized human plasma proteins.
- Author
-
Ulfig A, Schulz AV, Müller A, Lupilov N, and Leichert LI
- Subjects
- Acyltransferases metabolism, Antigens, Bacterial metabolism, Antioxidants pharmacology, Bacterial Proteins metabolism, Cell Line, Tumor, Chloramines analysis, Humans, Hydrophobic and Hydrophilic Interactions, Hypochlorous Acid pharmacology, Immunoglobulin G metabolism, Male, NADPH Oxidases metabolism, Neutrophil Activation drug effects, Oxidation-Reduction, Phosphatidylinositol 3-Kinases metabolism, Protein Aggregates drug effects, Respiratory Burst drug effects, Serum Albumin metabolism, Signal Transduction drug effects, Staurosporine pharmacology, Blood Proteins pharmacology, Halogenation, Immunologic Factors pharmacology
- Abstract
Hypochlorous acid (HOCl), a powerful antimicrobial oxidant, is produced by neutrophils to fight infections. Here, we show that N -chlorination, induced by HOCl concentrations encountered at sites of inflammation, converts blood plasma proteins into chaperone-like holdases that protect other proteins from aggregation. This chaperone-like conversion was reversible by antioxidants and was abrogated by prior methylation of basic amino acids. Furthermore, reversible N -chlorination of basic amino acid side chains is the major factor that converts plasma proteins into efficient activators of immune cells. Finally, HOCl-modified serum albumin was found to act as a pro-survival molecule that protects neutrophils from cell death induced by highly immunogenic foreign antigens. We propose that activation and enhanced persistence of neutrophils mediated by HOCl-modified plasma proteins, resulting in the increased and prolonged generation of ROS, including HOCl, constitutes a potentially detrimental positive feedback loop that can only be attenuated through the reversible nature of the modification involved., Competing Interests: AU, AS, AM, NL, LL No competing interests declared, (© 2019, Ulfig et al.)
- Published
- 2019
- Full Text
- View/download PDF