title: Hypohalous acids contribute to renal extracellular matrix damage in experimental diabetes.
abstract: In diabetes, toxic oxidative pathways are triggered by persistent hyperglycemia and contribute to diabetes complications. A major proposed pathogenic mechanism is the accumulation of protein modifications that are called advanced glycation end products. However, other nonenzymatic post-translational modifications may also contribute to pathogenic protein damage in diabetes. We demonstrate that hypohalous acid-derived modifications of renal tissues and extracellular matrix (ECM) proteins are significantly elevated in experimental diabetic nephropathy. Moreover, diabetic renal ECM shows diminished binding of α1β1 integrin consistent with the modification of collagen IV by hypochlorous (HOCl) and hypobromous acids. Noncollagenous (NC1) hexamers, key connection modules of collagen IV networks, are modified via oxidation and chlorination of tryptophan and bromination of tyrosine residues. Chlorotryptophan, a relatively minor modification, has not been previously found in proteins. In the NC1 hexamers isolated from diabetic kidneys, levels of HOCl-derived oxidized and chlorinated tryptophan residues W(28) and W(192) are significantly elevated compared with nondiabetic controls. Molecular dynamics simulations predicted a more relaxed NC1 hexamer tertiary structure and diminished assembly competence in diabetes; this was confirmed using limited proteolysis and denaturation/refolding. Our results suggest that hypohalous acid-derived modifications of renal ECM, and specifically collagen IV networks, contribute to functional protein damage in diabetes.
authors.affiliation: Department of Medicine, Vanderbilt University Medical Center, Nashville, TN.
authors.forename: Kyle L
authors.initials: KL
authors.lastname: Brown
authors.affiliation: Department of Medicine, Vanderbilt University Medical Center, Nashville, TN.
authors.forename: Carl
authors.initials: C
authors.lastname: Darris
authors.affiliation: Department of Biochemistry, Vanderbilt University Medical Center, Nashville, TN.
authors.forename: Kristie Lindsey
authors.initials: KL
authors.lastname: Rose
authors.affiliation: Institute of Imaging Science, Vanderbilt University Medical Center, Nashville, TN.
authors.forename: Otto A
authors.initials: OA
authors.lastname: Sanchez
authors.affiliation: Department of Medicine, Vanderbilt University Medical Center, Nashville, TN.
authors.forename: Hartman
authors.initials: H
authors.lastname: Madu
authors.affiliation: Berea College, Berea, KY.
authors.forename: Josh
authors.initials: J
authors.lastname: Avance
authors.affiliation: Yale University, New Haven, CT.
authors.forename: Nickolas
authors.initials: N
authors.lastname: Brooks
authors.affiliation: Department of Medicine, Vanderbilt University Medical Center, Nashville, TN.
authors.forename: Ming-Zhi
authors.initials: MZ
authors.lastname: Zhang
authors.affiliation: Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN.
authors.forename: Agnes
authors.initials: A
authors.lastname: Fogo
authors.affiliation: Department of Medicine, Vanderbilt University Medical Center, Nashville, TN.
authors.forename: Raymond
authors.initials: R
authors.lastname: Harris
authors.affiliation: Department of Medicine, Vanderbilt University Medical Center, Nashville, TN Department of Biochemistry, Vanderbilt University Medical Center, Nashville, TN Department of Pathology, Microbiology, and Immunology, Vanderbilt University Medical Center, Nashville, TN.
authors.forename: Billy G
authors.initials: BG
authors.lastname: Hudson
authors.affiliation: Department of Medicine, Vanderbilt University Medical Center, Nashville, TN paul.voziyan@vanderbilt.edu.
authors.forename: Paul
authors.initials: P
authors.lastname: Voziyan
mesh_terms: D000818:Animals; D001959:Bromates / Q000378:metabolism*; D003921:Diabetes Mellitus, Experimental / Q000378:metabolism* / Q000473:pathology*; D005109:Extracellular Matrix / Q000378:metabolism* / Q000473:pathology*; D006997:Hypochlorous Acid / Q000378:metabolism; D016023:Integrins / Q000378:metabolism; D007668:Kidney / Q000378:metabolism / Q000473:pathology; D008297:Male; D051379:Mice; D018345:Mice, Knockout; D056004:Molecular Dynamics Simulation; D052250:Nitric Oxide Synthase Type III / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley
chemical_list: D001959:Bromates; D016023:Integrins; D006997:Hypochlorous Acid; D052250:Nitric Oxide Synthase Type III; C027664:hypobromous acid