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Peroxynitrite and Hydrogen Peroxide Increase Arginase Activity through the RhoA/Rho Kinase (RAK) Pathway
Author(s) -
Chandra Surabhi,
Romero Maritza J,
Shatanawi Alia,
Caldwell Ruth B,
Caldwell Robert William
Publication year - 2010
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.24.1_supplement.959.4
Subject(s) - peroxynitrite , nadph oxidase , apocynin , chemistry , nitric oxide , arginase , rhoa , nitric oxide synthase , oxidative phosphorylation , rho associated protein kinase , superoxide , biochemistry , reactive oxygen species , arginine , signal transduction , enzyme , organic chemistry , amino acid
Nitric oxide (NO) produced from L‐arginine by NO synthase (NOS) is needed for normal vascular function. During diabetes, aging, and hypertension, arginase (ARG) competes with NOS for L‐arginine, reducing NO and increasing O 2 ·− production, via NOS uncoupling. Elevated O 2 ·− combines with NO to form peroxynitrite (ONOO − ) further reducing NO. Oxidative radicals increase ARG activity, though mechanism(s) involved are not known. We hypothesized that oxidative species increase ARG activity through the RAK pathway. To test this, we determined effects of the ONOO − generator (SIN‐1) or H 2 O 2 on ARG activity/expression in bovine aortic endothelial cells (EC). SIN‐1 (25 μM, 24 hr) increased ARG activity (35%) and expression (25%) which was prevented by pretreatment with ONOO − decomposition catalyst, FeTPPS (10 μM) or Rho kinase inhibitor, Y‐27632 (10 μM). Exposure to SIN‐1 (2 hr) increased membrane translocation of p115RhoGEF (20%), which activates RAK. Treatment with H 2 O 2 (25 μM, 8 hr) increased O 2 ·− production (71%), as well as ARG activity (50%) and expression (36%) which was prevented by pretreatment with the NADPH oxidase inhibitor apocynin (30 μM) or Y‐27632. Thus, our data indicate oxidative species ONOO − and H 2 O 2 increase ARG activity/expression through the RAK pathway. Further, effect of H 2 O 2 on ARG activity appears to be due to O 2 ·− formation via NADPH oxidase (Support NIH grant HL70215).