TY - JOUR
T1 - Chlorination and oxidation of the extracellular matrix protein laminin and basement membrane extracts by hypochlorous acid and myeloperoxidase
AU - Nybo, Tina
AU - Dieterich, Simon
AU - Gamon, Luke F.
AU - Chuang, Christine Y.
AU - Hammer, Astrid
AU - Hoefler, Gerald
AU - Malle, Ernst
AU - Rogowska-Wrzesinska, Adelina
AU - Davies, Michael J.
PY - 2019/1
Y1 - 2019/1
N2 - Basement membranes are specialized extracellular matrices that underlie arterial wall endothelial cells, with laminin being a key structural and biologically-active component. Hypochlorous acid (HOCl), a potent oxidizing and chlorinating agent, is formed in vivo at sites of inflammation via the enzymatic action of myeloperoxidase (MPO), released by activated leukocytes. Considerable data supports a role for MPO-derived oxidants in cardiovascular disease and particularly atherosclerosis. These effects may be mediated via extracellular matrix damage to which MPO binds. Herein we detect and quantify sites of oxidation and chlorination on isolated laminin-111, and laminin in basement membrane extracts (BME), by use of mass spectrometry. Increased modification was detected with increasing oxidant exposure. Mass mapping indicated selectivity in the sites and extent of damage; Met residues were most heavily modified. Fewer modifications were detected with BME, possibly due to the shielding effects. HOCl oxidised 30 (of 56 total) Met and 7 (of 24) Trp residues, and chlorinated 33 (of 99) Tyr residues; 3 Tyr were dichlorinated. An additional 8 Met and 10 Trp oxidations, 14 chlorinations, and 18 dichlorinations were detected with the MPO/H 2 O 2 /Cl - system when compared to reagent HOCl. Interestingly, chlorination was detected at Tyr 2415 in the integrin-binding region; this may decrease cellular adhesion. Co-localization of MPO-damaged epitopes and laminin was detected in human atherosclerotic lesions. These data indicate that laminin is extensively modified by MPO-derived oxidants, with structural and functional changes. These modifications, and compromised cell-matrix interactions, may promote endothelial cell dysfunction, weaken the structure of atherosclerotic lesions, and enhance lesion rupture.
AB - Basement membranes are specialized extracellular matrices that underlie arterial wall endothelial cells, with laminin being a key structural and biologically-active component. Hypochlorous acid (HOCl), a potent oxidizing and chlorinating agent, is formed in vivo at sites of inflammation via the enzymatic action of myeloperoxidase (MPO), released by activated leukocytes. Considerable data supports a role for MPO-derived oxidants in cardiovascular disease and particularly atherosclerosis. These effects may be mediated via extracellular matrix damage to which MPO binds. Herein we detect and quantify sites of oxidation and chlorination on isolated laminin-111, and laminin in basement membrane extracts (BME), by use of mass spectrometry. Increased modification was detected with increasing oxidant exposure. Mass mapping indicated selectivity in the sites and extent of damage; Met residues were most heavily modified. Fewer modifications were detected with BME, possibly due to the shielding effects. HOCl oxidised 30 (of 56 total) Met and 7 (of 24) Trp residues, and chlorinated 33 (of 99) Tyr residues; 3 Tyr were dichlorinated. An additional 8 Met and 10 Trp oxidations, 14 chlorinations, and 18 dichlorinations were detected with the MPO/H 2 O 2 /Cl - system when compared to reagent HOCl. Interestingly, chlorination was detected at Tyr 2415 in the integrin-binding region; this may decrease cellular adhesion. Co-localization of MPO-damaged epitopes and laminin was detected in human atherosclerotic lesions. These data indicate that laminin is extensively modified by MPO-derived oxidants, with structural and functional changes. These modifications, and compromised cell-matrix interactions, may promote endothelial cell dysfunction, weaken the structure of atherosclerotic lesions, and enhance lesion rupture.
KW - Extracellular matrix
KW - Hypochlorous acid
KW - Laminin
KW - Protein oxidation
KW - 3-chlorotyrosine
KW - Myeloperoxidase
U2 - 10.1016/j.redox.2018.10.022
DO - 10.1016/j.redox.2018.10.022
M3 - Journal article
C2 - 30476874
SN - 2213-2317
VL - 20
SP - 496
EP - 513
JO - Redox Biology
JF - Redox Biology
ER -
