TY - JOUR

T1 - Myeloperoxidase-derived oxidants selectively disrupt the protein core of the heparan sulfate proteoglycan perlecan

AU - Rees, Martin D

AU - Whitelock, John M

AU - Malle, Ernst

AU - Chuang, Christine Y

AU - Iozzo, Renato V

AU - Nilasaroya, Anastasia

AU - Davies, Michael Jonathan

PY - 2010/1

Y1 - 2010/1

N2 - The potent oxidants hypochlorous acid (HOCl) and hypobromous acid (HOBr) are produced extracellularly by myeloperoxidase, following release of this enzyme from activated leukocytes. The subendothelial extracellular matrix is a key site for deposition of myeloperoxidase and damage by myeloperoxidase-derived oxidants, with this damage implicated in the impairment of vascular cell function during acute inflammatory responses and chronic inflammatory diseases such as atherosclerosis. The heparan sulfate proteoglycan perlecan, a key component of the subendothelial extracellular matrix, regulates important cellular processes and is a potential target for HOCl and HOBr. It is shown here that perlecan binds myeloperoxidase via its heparan sulfate side chains and that this enhances oxidative damage by myeloperoxidase-derived HOCl and HOBr. This damage involved selective degradation of the perlecan protein core without detectable alteration of its heparan sulfate side chains, despite the presence of reactive GlcNH(2) residing within this glycosaminoglycan. Modification of the protein core by HOCl and HOBr (measured by loss of immunological recognition of native protein epitopes and the appearance of oxidatively-modified protein epitopes) was associated with an impairment of its ability to support endothelial cell adhesion, with this observed at a pathologically-achievable oxidant dose of 425nmol oxidant/mg protein. In contrast, the heparan sulfate chains of HOCl/HOBr-modified perlecan retained their ability to bind FGF-2 and collagen V and were able to promote FGF-2-dependent cellular proliferation. Collectively, these data highlight the potential role of perlecan oxidation, and consequent deregulation of cell function, in vascular injuries by myeloperoxidase-derived HOCl and HOBr.

AB - The potent oxidants hypochlorous acid (HOCl) and hypobromous acid (HOBr) are produced extracellularly by myeloperoxidase, following release of this enzyme from activated leukocytes. The subendothelial extracellular matrix is a key site for deposition of myeloperoxidase and damage by myeloperoxidase-derived oxidants, with this damage implicated in the impairment of vascular cell function during acute inflammatory responses and chronic inflammatory diseases such as atherosclerosis. The heparan sulfate proteoglycan perlecan, a key component of the subendothelial extracellular matrix, regulates important cellular processes and is a potential target for HOCl and HOBr. It is shown here that perlecan binds myeloperoxidase via its heparan sulfate side chains and that this enhances oxidative damage by myeloperoxidase-derived HOCl and HOBr. This damage involved selective degradation of the perlecan protein core without detectable alteration of its heparan sulfate side chains, despite the presence of reactive GlcNH(2) residing within this glycosaminoglycan. Modification of the protein core by HOCl and HOBr (measured by loss of immunological recognition of native protein epitopes and the appearance of oxidatively-modified protein epitopes) was associated with an impairment of its ability to support endothelial cell adhesion, with this observed at a pathologically-achievable oxidant dose of 425nmol oxidant/mg protein. In contrast, the heparan sulfate chains of HOCl/HOBr-modified perlecan retained their ability to bind FGF-2 and collagen V and were able to promote FGF-2-dependent cellular proliferation. Collectively, these data highlight the potential role of perlecan oxidation, and consequent deregulation of cell function, in vascular injuries by myeloperoxidase-derived HOCl and HOBr.

KW - Animals

KW - Bromates

KW - Cell Adhesion

KW - Cells, Cultured

KW - Collagen Type V

KW - Endothelial Cells

KW - Epitopes

KW - Fibroblast Growth Factor 2

KW - Glycosaminoglycans

KW - Heparan Sulfate Proteoglycans

KW - Humans

KW - Hypochlorous Acid

KW - Oxidants

KW - Oxidation-Reduction

KW - Peroxidase

KW - Protein Binding

U2 - 10.1016/j.matbio.2009.09.005

DO - 10.1016/j.matbio.2009.09.005

M3 - Journal article

C2 - 19788922

VL - 29

SP - 63

EP - 73

JO - Matrix Biology

JF - Matrix Biology

SN - 0945-053X

IS - 1

ER -