Site-Specific Nitration of Apolipoprotein A-I at Tyrosine 166 Is Both Abundant within Human Atherosclerotic Plaque and Dysfunctional

Authors

Joseph A. DiDonato, Cleveland State UniversityFollow
Kulwant Aulak, Cleveland State University
Ying Huang, Cleveland State University
Matthew A. Wagner, Cleveland Clinic
Gary Gerstenecker, Cleveland State University
Celalettin Topbas, Cleveland State University
Valentin Gogonea, Cleveland State UniversityFollow
Anthony J. DiDonato, Cleveland Clinic
W.H. Wilson Tang, Cleveland State University
Ryan A. Mehl, Oregon State University
Paul L. Fox, Cleveland State University
Edward F. Plow, Cleveland State UniversityFollow
Jonathan D. Smith, Cleveland State UniversityFollow
Edward A. Fisher, Cleveland State University
Stanley L. Hazen, Cleveland State UniversityFollow

Document Type

Article

Publication Date

4-11-2014

Publication Title

The Journal of Biological Chemistry

Abstract

We reported previously that apolipoprotein A-I (apoA-I) is oxidatively modified in the artery wall at tyrosine 166 (Tyr166), serving as a preferred site for post-translational modification through nitration. Recent studies, however, question the extent and functional importance of apoA-I Tyr166 nitration based upon studies of HDL-like particles recovered from atherosclerotic lesions. We developed a monoclonal antibody (mAb 4G11.2) that recognizes, in both free and HDL-bound forms, apoA-I harboring a 3-nitrotyrosine at position 166 apoA-I (NO2-Tyr166-apoA-I) to investigate the presence, distribution, and function of this modified apoA-I form in atherosclerotic and normal artery wall. We also developed recombinant apoA-I with site-specific 3-nitrotyrosine incorporation only at position 166 using an evolved orthogonal nitro-Tyr-aminoacyl-tRNA synthetase/tRNACUA pair for functional studies. Studies with mAb 4G11.2 showed that NO2-Tyr166-apoA-I was easily detected in atherosclerotic human coronary arteries and accounted for ∼8% of total apoA-I within the artery wall but was nearly undetectable (>100-fold less) in normal coronary arteries. Buoyant density ultracentrifugation analyses showed that NO2-Tyr166-apoA-I existed as a lipid-poor lipoprotein with <3% recovered within the HDL-like fraction (d = 1.063–1.21). NO2-Tyr166-apoA-I in plasma showed a similar distribution. Recovery of NO2-Tyr166-apoA-I using immobilized mAb 4G11.2 showed an apoA-I form with 88.1 ± 8.5% reduction in lecithin-cholesterol acyltransferase activity, a finding corroborated using a recombinant apoA-I specifically designed to include the unnatural amino acid exclusively at position 166. Thus, site-specific nitration of apoA-I at Tyr166 is an abundant modification within the artery wall that results in selective functional impairments. Plasma levels of this modified apoA-I form may provide insights into a pathophysiological process within the diseased artery wall.

Comments

This work was supported, in whole or in part, by National Institutes of Health Grants P01HL098055, P01HL076491, and HL17964.

Recommended Citation

DiDonato, Joseph A.; Aulak, Kulwant; Huang, Ying; Wagner, Matthew A.; Gerstenecker, Gary; Topbas, Celalettin; Gogonea, Valentin; DiDonato, Anthony J.; Tang, W.H. Wilson; Mehl, Ryan A.; Fox, Paul L.; Plow, Edward F.; Smith, Jonathan D.; Fisher, Edward A.; and Hazen, Stanley L., "Site-Specific Nitration of Apolipoprotein A-I at Tyrosine 166 Is Both Abundant within Human Atherosclerotic Plaque and Dysfunctional" (2014). Chemistry Faculty Publications. 329.
https://engagedscholarship.csuohio.edu/scichem_facpub/329

DOI

10.1074/jbc.M114.556506

Version

Publisher's PDF

Volume

289

Issue

15