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Cytochrome P450 ω‐hydroxylase and COX‐2 Inhibition Reduces Stretch‐Induced Renal Fibrosis in HK‐2 Cells
Author(s) -
Avedissian Hari,
Farhat Kalil,
Alexander Larry
Publication year - 2015
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.29.1_supplement.976.1
Subject(s) - fibronectin , arachidonic acid , chemistry , phospholipase a2 , endocrinology , prostaglandin , medicine , cyclooxygenase , blot , prostaglandin e2 , fibrosis , biochemistry , biology , extracellular matrix , enzyme , gene
Fibronectin matrix deposition is a hallmark of renal fibrosis, which ultimately leads to end‐stage renal failure. We have previously shown that the expression of fibronectin is increased by arachidonic acid in human renal proximal tubular epithelial (HK‐2) cells. Here we found that cyclic mechanical stretch up‐regulated protein levels of fibronectin by using Western blotting analysis. Using pharmacological inhibitors of phospholipase A 2 (PLA 2 ) or arachidonic acid metabolic pathways revealed that cytosolic phospholipase A 2 (cPLA 2 ), cytochrome P450 (CYP) ω‐hydroxylase, and cyclooxygenase‐2 (COX‐2) isoenzymes are involved in mechanical stretch‐induced up‐regulation of fibronectin. Indeed, mechanical stretch significantly increased 20‐hydroxyeicosatetraenoic acid (20‐HETE) and prostaglandin E 2 (PGE 2 ) production, metabolites of CYP ω‐hydroxylase and COX‐2, respectively, compared with control. Likewise, exogenous 20‐HETE or PGE 2 administration also elicited an increase in fibronectin expression. In line with this, the selective inhibitor of 20‐HETE synthesis HET0016 and COX‐2 inhibitor NS398 prevented fibronectin synthesis in response to mechanical stretch. In western blotting analysis, mechanical stretch increased the activity of ERK1/2, p38 MAPK, and JNK and PD 98059 or SB 203580 blocked the effect of mechanical stretch on fibronectin expression. These data provide the first evidence, in HK‐2 cells, of production of fibronectin by cyclic mechanical stretch. Moreover, our results provide evidence that blockade of CYP ω‐hydroxylase and COX‐2 may provide significant anti‐fibrotic therapy for treatment of obstructive nephropathy.