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Medical AI Inquiry: You was designed to assist in medical decision-making based on the provided user questions. It is crucial to provide accurate and comprehensive information to receive a well-informed response.  Labels: OBJECTIVE, RESULTS. Meshes: 5' Flanking Region, Animals, Arteries, Cattle, Cells, Cultured, Endothelium, Vascular, Gene Expression Regulation, Enzymologic, Humans, Intramolecular Oxidoreductases, JNK Mitogen-Activated Protein Kinases, Lipocalins, Phosphorylation, RNA Stability, Response Elements, Stress, Mechanical, Transcription Factor AP-1, Transcriptional Activation, Umbilical Veins.
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Does activator protein-1 mediate shear stress-induced prostaglandin d synthase gene expression in vascular endothelial cells? Context: We attempted to determine the molecular mechanism of fluid shear stress-induced lipocalin-type prostaglandin D synthase (l-PGDS) expression in vascular endothelial cells. We examined the promoter region of the l-PGDS gene by loading laminar shear stress (20 dyne/cm2), using a parallel-plate flow chamber, on endothelial cells transfected with luciferase reporter vectors containing the 5'-flanking regions of the human l-PGDS gene. A deletion mutant analysis revealed that a shear stress-responsive element resided in the region between -2607 and -2523 bp. A mutation introduced into the putative binding site for activator protein-1 (AP-1) within this region eliminated the response to shear stress. In an electrophoretic mobility shift assay, shear stress stimulated nuclear protein binding to the AP-1 binding site, which was supershifted by antibodies to c-Fos and c-Jun. Shear stress elevated the c-Jun phosphorylation level in a time-dependent manner, similar to that of l-PGDS gene expression. SP600125, a c-Jun N-terminal kinase inhibitor, decreased the c-Jun phosphorylation, DNA binding of AP-1, and l-PGDS expression induced by shear stress. Additionally, an mRNA chase experiment using actinomycin D demonstrated that shear stress did not stabilize l-PGDS mRNA.
assistant
Shear stress induces l-PGDS expression by transcriptional activation through the AP-1 binding site. Final Decision: yes