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A keratin peptide inhibits mannose-binding lectin.
M C Montalto1, C D Collard, J A Buras
1Department of Anesthesiology, Perioperative and Pain Medicine, Center for Experimental Therapeutics and Reperfusion Injury, Brigham and Women's Hospital, Harvard Medical School, Boston, MA 02115, USA.
Journal of Immunology (Baltimore, Md. : 1950)
|March 10, 2001
Summary
A novel peptide mimics N-acetyl-D-glucosamine to inhibit the mannose-binding lectin pathway (LCP), reducing endothelial injury from oxidative stress and complement activation.
Area of Science:
- Immunology
- Molecular Biology
- Biochemistry
Background:
- Oxidative stress causes endothelial injury, significantly mediated by complement activation.
- The lectin complement pathway (LCP), initiated by mannose-binding lectin (MBL), is crucial for complement activation on endothelial cells post-oxidative stress.
- Targeting MBL binding is key to understanding LCP's role in disease.
Purpose of the Study:
- To investigate if the cytokeratin peptide SFGSGFGGGY, a mimic of N-acetyl-D-glucosamine (GlcNAc), can inhibit MBL binding and LCP function.
- To assess the peptide's efficacy in preventing endothelial cell activation and injury under oxidative stress conditions.
Main Methods:
- BIAcore 3000 biosensor used for binding kinetics and competition assays.
- Cell surface ELISA and confocal microscopy to quantify MBL and C3 deposition.
- Assessment of complement-dependent VCAM-1 expression on endothelial cells.
Main Results:
- The peptide SFGSGFGGGY demonstrated concentration-dependent inhibition of MBL binding to GlcNAc.
- The peptide binds to MBL with an affinity (K(D)) of 5 x 10(-5) mol/L.
- Peptide pretreatment significantly reduced MBL and C3 deposition and VCAM-1 expression on oxidatively stressed endothelial cells.
Conclusions:
- The GlcNAc-mimicking peptide specifically binds to MBL.
- This peptide effectively inhibits the LCP's pro-inflammatory actions on oxidatively stressed endothelial cells.
- The findings highlight a potential therapeutic strategy for LCP-mediated endothelial injury.