Increased expression of endothelial lipase in rat models of hypertension.

OBJECTIVE To gain a better understanding of the involvement of endothelial lipase (EL) in vascular disease, we examined whether the EL expression is regulated in animal models of hypertension. METHODS The rat cDNA homologue of EL was identified using reverse transcription-polymerase chain reaction. Cultured rat aortic smooth muscle cells were stimulated with angiotensin II (Ang II) and phorbol 12-myristate 13-acetate (PMA), and EL mRNA expression was analyzed by Northern blotting. EL mRNA levels in tissues from stroke-prone spontaneously hypertensive rats (SHR-SP) and Ang II-induced hypertensive rats were evaluated using RNase protection assays. RESULTS Rat EL cDNA encoded a protein containing 493 amino acid residues including a signal peptide, and shares 91.9% and 80.9% sequence homology with murine and human EL, respectively. Northern blotting revealed that EL was expressed in a wide range of rat tissues. In cultured rat aortic smooth muscle cells, Ang II and PMA increased EL mRNA levels by 2.9- and 3.3-fold, respectively. In Ang II-induced hypertensive rats, EL expression was upregulated in the aorta, heart, and lung. In SHR-SP, EL expression was upregulated in the aorta and heart. CONCLUSION EL expression is increased in rat models of hypertension. Thus, EL might have a role in the local pathophysiology of vascular diseases.