12-lipoxygenase pathway increases aldosterone production, 3',5'-cyclic adenosine monophosphate response element-binding protein phosphorylation, and p38 mitogen-activated protein kinase activation in H295R human adrenocortical cells.
Evidence suggests that the 12-lipoxygenase (LO) pathway mediates angiotensin II (Ang II)-induced aldosterone synthesis in adrenal glomerulosa cells. To study the mechanisms of 12-LO pathway on aldosterone synthesis, the human adrenocortical cell line, H295R, was transiently transfected with a mouse leukocyte type of 12-LO. Overexpression of 12-LO stimulated aldosterone production 2.7-fold as well as the reporter gene activity of CYP11B2 gene-encoding human aldosterone synthase by 5-fold over that in mock-transfected cells. Ang II further enhanced aldosterone production, which could be blocked by a 12-LO inhibitor, baicalein, in mock cells and cells overexpressing 12-LO. Ang II stimulated cAMP response element-binding protein (CREB) phosphorylation in a dose- and time-dependent fashion in parent H295R cells. Overexpression of 12-LO increased phosphorylation of CREB/activating transcription factor (ATF)-1 1.5-fold over that in mock cells under basal conditions. Ang II led to a further 5.2- and 7.5-fold increase in mock cells and 12-LO cells, respectively. Overexpression of 12-LO induced p38 MAPK activation. The 12-LO product, 12-hydroxyeicosatetraenoic acid, increased phosphorylation of CREB/ATF-1 3.6-fold and phosphorylation of p38 MAPK 8-fold over basal. The p38 MAPK inhibitor SB203580 inhibited Ang II- and 12-LO pathway-induced phosphorylated CREB/ATF-1, suggesting a role of p38 MAPK in Ang II and 12-LO pathway signaling. These results suggest that 12-LO stimulation leads to aldosterone production in H295R cells in part through activation of CREB/ATF-1 and p38 MAPK pathway.
Gu
Jiali
J
Division of Endocrinology, Department of Internal Medicine, University of Virginia, Charlottesville, Virginia 22908, USA.
Wen
Yeshao
Y
Mison
Angeles
A
Nadler
Jerry L
JL
D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid / Q000494:pharmacology; D051697:Activating Transcription Factor 1; D048868:Adaptor Proteins, Signal Transducing; D000302:Adrenal Cortex / Q000166:cytology / Q000201:enzymology*; D000450:Aldosterone / Q000096:biosynthesis*; D000804:Angiotensin II / Q000494:pharmacology; D001092:Arachidonate 12-Lipoxygenase / Q000235:genetics / Q000378:metabolism*; D002352:Carrier Proteins / Q000378:metabolism; D002478:Cells, Cultured; D017362:Cyclic AMP Response Element-Binding Protein / Q000378:metabolism*; D019405:Cytochrome P-450 CYP11B2 / Q000235:genetics; D004268:DNA-Binding Proteins; D015971:Gene Expression Regulation, Enzymologic / Q000187:drug effects / Q000502:physiology; D017930:Genes, Reporter; D006801:Humans; D008156:Luciferases / Q000235:genetics; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases / Q000378:metabolism*; D009419:Nerve Tissue Proteins; D010766:Phosphorylation; D014157:Transcription Factors / Q000378:metabolism; D014662:Vasoconstrictor Agents / Q000494:pharmacology; D048051:p38 Mitogen-Activated Protein Kinases
D051697:Activating Transcription Factor 1; D048868:Adaptor Proteins, Signal Transducing; D002352:Carrier Proteins; D017362:Cyclic AMP Response Element-Binding Protein; D004268:DNA-Binding Proteins; C485750:MAPK8IP3 protein, human; D009419:Nerve Tissue Proteins; D014157:Transcription Factors; D014662:Vasoconstrictor Agents; D000804:Angiotensin II; D000450:Aldosterone; D019377:12-Hydroxy-5,8,10,14-eicosatetraenoic Acid; D001092:Arachidonate 12-Lipoxygenase; D008156:Luciferases; D019405:Cytochrome P-450 CYP11B2; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020928:Mitogen-Activated Protein Kinases; D048051:p38 Mitogen-Activated Protein Kinases