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Chemoattractant activity of Staphylococcus aureus serine proteinase modified human plasma alpha-1-proteinase
1Department of Microbiology and Immunology, Jan Zurzycki Institute of Molecular Biology, Jagiellonian University, Cracow, Poland.
Abstract:
S. aureus serine proteinase inactivates human alpha-1-proteinase inhibitor (alpha-1-PI) by attacking a single peptide bond between Glu354 and Ala355 giving a modified inhibitor which is a tight complex of Mr = 4,000 and 48,000 fragments. In the present paper we show that this proteolytically inactivated alpha-1-PI is a potent chemotactic factor for human neutrophiles at a nanomolar concentration, and we discuss its potential involvement in the inflammatory reaction due to S. aureus infections.
Insights
Staphylococcus aureus serine proteinase inactivates human alpha-1-proteinase inhibitor (alpha-1-PI). This modified alpha-1-PI acts as a potent chemotactic factor, attracting neutrophils and potentially driving inflammation in S. aureus infections.
Area of Science:
- Biochemistry
- Immunology
- Microbiology
Background:
- Staphylococcus aureus serine proteinase is known to modify human alpha-1-proteinase inhibitor (alpha-1-PI).
- Alpha-1-PI plays a crucial role in regulating inflammatory responses by inhibiting proteases.
Purpose of the Study:
- To investigate the functional consequences of alpha-1-PI inactivation by S. aureus serine proteinase.
- To determine if the modified alpha-1-PI exhibits any biological activity, specifically in neutrophil recruitment.
- To explore the potential role of this interaction in the inflammatory process during S. aureus infections.
Main Methods:
- Proteolytic digestion of human alpha-1-PI by S. aureus serine proteinase.
- Characterization of the resulting modified alpha-1-PI complex.
- Chemotaxis assays using human neutrophils to assess the biological activity of modified alpha-1-PI at nanomolar concentrations.
Main Results:
- S. aureus serine proteinase cleaves human alpha-1-PI at the Glu354-Ala355 peptide bond.
- The resulting modified alpha-1-PI forms a tight complex of 4,000 and 48,000 fragments.
- Proteolytically inactivated alpha-1-PI demonstrates potent chemotactic activity for human neutrophils at nanomolar concentrations.
Conclusions:
- Inactivation of alpha-1-PI by S. aureus serine proteinase generates a biologically active fragment.
- This modified alpha-1-PI acts as a potent chemoattractant for neutrophils.
- The findings suggest a novel mechanism by which S. aureus may contribute to inflammatory reactions through modulation of alpha-1-PI.