ABSTRACT
A 51-year-old white woman with a past medical history significant for steroid-dependent ulcerative colitis, rheumatoid arthritis, and diabetes mellitus presented to the hospital with fever and painful, erythematous subcutaneous nodules on the medical aspects of both thighs. Histopathologic examination showed features suggestive of an abscess, but her condition failed to improve with intravenous broad-spectrum antibiotics. Molecular studies detected T cell receptor-ß gene rearrangements. The lesions later exhibited signs of necrosis, requiring multiple debridements as well as therapy with hyperbaric oxygen. She was later referred to the MD Anderson Cancer Center for evaluation for possible subcutaneous panniculitis-like T cell lymphoma.
Subject(s)
Dermatitis/diagnosis , Granuloma/diagnosis , Lymphoma, T-Cell/diagnosis , Panniculitis/diagnosis , Debridement/methods , Dermatitis/pathology , Dermatitis/therapy , Diagnosis, Differential , Female , Granuloma/pathology , Granuloma/therapy , Humans , Hyperbaric Oxygenation , Lymphoma, T-Cell/pathology , Middle Aged , Necrosis , Panniculitis/pathology , Panniculitis/therapy , Skin Neoplasms/diagnosis , Skin Neoplasms/pathologyABSTRACT
Endothelium-derived epoxyeicosatrienoic acids (EETs) have numerous vascular activities mediated by G protein-coupled receptors. Long-chain free fatty acids and EETs activate GPR40, prompting us to investigate the role of GPR40 in some vascular EET activities. 14,15-EET, 11,12-EET, arachidonic acid, and the GPR40 agonist GW9508 increase intracellular calcium concentrations in human GPR40-overexpressing HEK293 cells (EC50 = 0.58 ± 0.08 µm, 0.91 ± 0.08 µm, 3.9 ± 0.06 µm, and 19 ± 0.37 nm, respectively). EETs with cis- and trans-epoxides had similar activities, whereas substitution of a thiirane sulfur for the epoxide oxygen decreased the activities. 8,9-EET, 5,6-EET, and the epoxide hydrolysis products 11,12- and 14,15-dihydroxyeicosatrienoic acids were less active than 11,12-EET. The GPR40 antagonist GW1100 and siRNA-mediated GPR40 silencing blocked the EET- and GW9508-induced calcium increases. EETs are weak GPR120 agonists. GPR40 expression was detected in human and bovine endothelial cells (ECs), smooth muscle cells, and arteries. 11,12-EET concentration-dependently relaxed preconstricted coronary arteries; however, these relaxations were not altered by GW1100. In human ECs, 11,12-EET increased MAP kinase (MAPK)-mediated ERK phosphorylation, phosphorylation and levels of connexin-43 (Cx43), and expression of cyclooxygenase-2 (COX-2), all of which were inhibited by GW1100 and the MAPK inhibitor U0126. Moreover, siRNA-mediated GPR40 silencing decreased 11,12-EET-induced ERK phosphorylation. These results indicated that GPR40 is a low-affinity EET receptor in vascular cells and arteries. We conclude that epoxidation of arachidonic acid to EETs enhances GPR40 agonist activity and that 11,12-EET stimulation of GPR40 increases Cx43 and COX-2 expression in ECs via ERK phosphorylation.
