Effect of PAR2 in regulating TNF-α and NAD(P)H oxidase in coronary arterioles in type 2 diabetic mice.
Protease-activated receptor-2 (PAR2) is expressed in endothelial cells and mediates endothelium-dependent vasodilation. We hypothesized that PAR2 regulates tumor necrosis factor-alpha (TNF-α)-induced coronary arteriolar dysfunction in type 2 diabetic (db/db) mice. To test this, coronary arterioles from WT control, db/db, db/db mice treated with PAR2 antagonist FSLLRY-NH₂ (db/db+FSLLRY-NH₂) and db/db mice null for TNF (db(TNF-)/db(TNF-)) were isolated and pressurized (60 cmH₂O) without flow. Although vasodilation to the endothelium-independent vasodilator sodium nitroprusside (SNP) was not different among WT, db/db, db/db+FSLLRY-NH₂ and db(TNF-)/db(TNF-), endothelium-dependent acetylcholine (ACh)- and flow-mediated vasodilation were impaired in db/db mice but were enhanced in db(TNF-)/db(TNF-) mice and db/db mice treated with PAR2 antagonist. NOS inhibitor N (G)-nitro-L-arginine-methyl ester (L-NAME) significantly reduced ACh-induced dilation in WT, db(TNF-)/db(TNF-) and db/db+FSLLRY-NH₂, but did not alter the vasodilation in db/db mice. In contrast, cyclooxygenase (COX) inhibitor indomethacin (Indo) did not alter ACh-induced vasodilation in these four groups of mice. PAR2-activating peptide (PAR2-AP, 2-Furoyl-LIGRLO-am)-induced dilation was higher in db/db mice than that in WT, db(TNF-)/db(TNF-) and db/db mice treated with PAR2 antagonist. These effects were abolished by denudation, or in the presence of L-NAME or Indo. Protein expressions of TNF-α, PAR2, gp91(phox) and p47(phox) in the heart and isolated coronary arterioles were higher in db/db mice compared to WT mice. Administration of PAR2 antagonist to db/db mice reduced protein expression of TNF-α, gp91(phox) and PAR2. Protein expression of gp91(phox) and p47(phox) was lower in db(TNF-)/db(TNF-) compared to db/db mice. These results indicate that PAR2 plays a pivotal role in endothelial dysfunction in type 2 diabetes by up-regulating the expression/production of TNF-α and activating NAD(P)H oxidase subunit p47(phox).
Division of Cardiovascular Medicine, Department of Internal Medicine, Medical Pharmacology and Physiology and Nutrition and Exercise Physiology, Dalton Cardiovascular Research Center, University of Missouri-Columbia, Columbia, MO 65211, USA.
Yoonjung
Y
Park
Jiyeon
J
Yang
Hanrui
H
Zhang
Xiaonai
X
Chen
Cuihua
C
Zhang
D000818:Animals; D001160:Arterioles / Q000503:physiopathology; D002478:Cells, Cultured; D003331:Coronary Vessels / Q000201:enzymology*; D003924:Diabetes Mellitus, Type 2 / Q000201:enzymology* / Q000503:physiopathology; D004730:Endothelium, Vascular / Q000503:physiopathology; D005260:Female; D005786:Gene Expression Regulation; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D019255:NADPH Oxidases / Q000378:metabolism*; D009842:Oligopeptides / Q000378:metabolism; D044464:Receptor, PAR-2 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000378:metabolism*; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism*; D014664:Vasodilation
C487404:2-furoyl-LIGRLO-amide; D009842:Oligopeptides; D044464:Receptor, PAR-2; D014409:Tumor Necrosis Factor-alpha; D019255:NADPH Oxidases