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Differential targeting of NADPH oxidase to lipid rafts of renal proximal tubule cells
Author(s) -
Han Weixing,
Villar Van AM,
Li Hewang,
Jose Pedro A,
Yu Peiying
Publication year - 2007
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.21.6.a900
Subject(s) - nox4 , lipid raft , endocrinology , medicine , nadph oxidase , fenoldopam , chemistry , receptor , agonist , biology , cholesterol , oxidative stress
NADPH oxidase (Nox)‐dependent reactive oxygen species (ROS) production has been implicated in the pathogenesis of hypertension. D1‐like receptors (D1R‐like), G proteins, and several signaling molecules are enriched in lipid rafts in renal proximal tubule cells (RPTCs) from normotensive Wistar‐Kyoto rats (WKYs). We tested the hypothesis that Nox isoforms and subunits are regulated by D1R‐like in lipid rafts in RPTCs from WKYs and spontaneously hypertensive rats (SHRs). We found that basal levels of Nox2 mRNA and protein were higher in SHRs than in WKYs. Nox2 and Nox4 proteins were differentially targeted to lipid rafts fractions (LRFs) in both cell lines. More Nox4 (47%) protein was in LRFs in WKYs than in SHRs (20%) (P<0.01, n=3) while more Rac1 protein (58%) was in LRFs in SHR than in WKYs (30%) (P<0.05, n=3). Methyl‐â‐cyclodextrin (CD), which depletes cell cholesterol, markedly decreased in abundance of Nox2, Nox4, and Rac1 in LRFs. Basal Nox activity was 3‐fold higher in SHRs than in WKYs, but was inhibited to a similar degree by the D1R‐like agonist, fenoldopam (1 umol/L/20 min), in WKYs (48±5%) and in SHRs (41±2%). CD decreased basal Nox activity to a greater extent in WKYs (56±1%) than in SHRs (43±4%) (P<0.05, n=3/group). Addition of cholesterol reversed the effect of CD on Nox activity in WKYs. Fenoldopam decreased the quantity of Nox2 protein in LRFs similarly in WKYs and in SHRs and decreased association of the D1B dopamine receptor with Nox2, and p67phox with Nox2 in WKYs. Taken together, a D1‐like receptor (probably rat D1B) decreases ROS, in part, by interfering with the distribution and assembly of Nox subunits in membrane microdomains. (1601) This work was supported by grants from the NIH (HL23081, DK52612, HL68686, HL074940, and DK39308).