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The Role of Epigenetic Mechanisms and Matrix Remodeling Enzymes in Oxidative Stress Induced Loss of the Microvascular Endothelial Glycocalyx
Author(s) -
Ali Mohamed M,
Mahmoud Abeer M,
Phillips Shane A
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1276.7
Subject(s) - glycocalyx , oxidative stress , microbiology and biotechnology , chemistry , matrix metalloproteinase , endothelial stem cell , endothelium , extracellular matrix , biology , biochemistry , endocrinology , in vitro
The integrity of endothelial glycocalyx is crucial for normal endothelial function and endothelial response to shear stress. Endothelial glycocalyx also tethers and concentrates the extracellular superoxide dismutase (ecSOD) which protects the endothelium against the oxidative damage of reactive oxygen species (ROS). Degradation of endothelial glycocalyx results in endothelial dysfunction and vascular remodeling. The proteolytic enzymes Matrix Metalloproteinases (MMPs) are capable of disrupting endothelial cell surface proteins such as syndecans resulting in derangements of endothelial glycocalyx. We sought to 1) test the role of MMPs and oxidative stress in disrupting the endothelial glycobiology 2) to determine the role of oxidative stress in the epigenetic regulation of this response. To this end, we experimentally induced oxidative stress in human adipose microvascular endothelial cells (HAMECs) in the presence or absence of exogenous hydrogen peroxide (H 2 O 2 , 2×10 −4 mol/L; 4 hours ) and endogenous oxidative stress buthionine sulfoximine (BSO; 10 −3 mol/L) and MMP inhibitors. We found that either H 2 O 2 or BSO, induced a 2–3 fold increase in MMPs (MMP1, MMP2 and MMP3) and a 3–5 fold increase in ADAMs (ADAM10 and ADAM17). Consequently, there was a reduction in protein levels of syndecan‐1 and ecSOD in the total cell lysate and increases in levels of syndecan‐1 ectodomain and ecSOD in cell culture media (4 folds and 5 folds, respectively) detected by immunoprecipitation and Western blotting. The upregulation of MMPS was accompanied by a decline of the mRNA and protein levels of their inhibitors, tissue inhibitors of MMPs (TIMPs; 2–3 fold). Interestingly, we found that the histone deacetylase (HDAC) inhibitor Trichostatin A (TSA) (5×10 −6 mol/L) normalized MMP expression and restored TIMP 1 and TIMP 3 after H 2 O 2 or BSO. Pharmacological inhibition of MMPs using marimastat (50 μM) and lisinopril (10 μM) mitigated the effect of oxidative stress on the glycocalyx. Using immunofluorescent labeled wheat germ agglutinin, we found that lisinopril and marimastat effectively restored the cell surface density of heparan sulfate glycosaminoglycans (HS‐GAGs), Syndecans and ecSOD on the endothelial cell surface. Lastly, we found that lisinopril decreased HDAC mRNA expression induced by H 2 O 2 suggesting an epigenetic mechanism of lisinopril on responses to oxidative stress. In conclusion, our findings suggest that oxidative stress induced loss of the endothelial glycocalyx involves epigenetic regulation of matrix metalloproteinases that results in the shedding of ecSOD and s yndecans . These data shed light on a therapeutically targetable epigenetic regulatory mechanism by which oxidative stress may induce vascular remodeling and endothelial dysfunction. Support or Funding Information NIH RO1s HL095701, HL095701‐01A2S (SAP), American Heart Association Grant 15POST24480172 (AMM)