Mast Cell-derived Prostaglandin D2 Controls Hyaluronan Synthesis in Human Orbital Fibroblasts via DP1 Activation

Abstract

Thyroid eye disease (TED) is a debilitating disorder characterized by the accumulation of adipocytes and hyaluronan (HA).Production of HA by fibroblasts leads to remarkable increases in tissue volume and to the anterior displacement of the eyes. Prostaglandin D 2 (PGD 2 ), mainly produced by mast cells, promotes orbital fibroblast adipogenesis. The mechanism by which PGD 2 influences orbital fibroblasts and their synthesis of HA is poorly understood. We report here that mast cell-derived PGD 2 is a key factor that promotes HA biosynthesis by orbital fibroblasts. Primary orbital fibroblasts from TED patients were isolated and used to test the effects of PGD 2 , prostaglandin J 2 , as well as prostaglandin D receptor (DP) agonists and antagonists on HA synthesis. The expression of HA synthase (HAS), hyaluronidase, DP1, and DP2 mRNA levels was assessed by PCR. Small interfering RNAs against HAS1 or HAS2 were used to assess the importance

International Union of Basic and Clinical Pharmacology. LXXXIII: Classification of Prostanoid Receptors, Updating 15 Years of Progress

“…Finally, DP 1 receptors have been implicated in the development of thyroid eye disease, which affects approximately 40% of patients with Graves hyperthyroidism. DP 1 receptors were found to be an important factor in promoting hyaluronan production, which would be a major contribution to exophthalmos (Guo et al, 2010). Thus, laropiprant would be of potential value in this debilitating ophthalmic condition.…”

Peroxisome Proliferator-activated Receptor γ Ligands Inhibit Transforming Growth Factor-β-induced, Hyaluronan-dependent, T Cell Adhesion to Orbital Fibroblasts

“…Knockdown-We recently demonstrated that HAS2 is the dominant isoform responsible for increased HA synthesis by orbital fibroblasts in response to prostaglandin D 2 (47). To test the involvement of HAS enzymes in the TGF-␤-mediated response, siRNA was used to selectively knock down HAS1 or HAS2 mRNA levels in fibroblasts.…”

“…For PPAR␥ mRNA detection, 4 days after transfection, RNA was prepared as above, and PPAR␥1 and PPAR␥2 mRNA levels were analyzed using realtime PCR. HAS1 and HAS2 siRNAs (Santa Cruz Biotechnology) were also used to knock down HAS1 and HAS2 mRNA expression, respectively, as described previously (47). After 24 h of transfection, the cells were serum-starved and treated with TGF-␤1 for 24 h before further experiment.…”

“…Primers for human HAS1, -2, -and 3 and 7 S and the qRT-PCR method to detect relative abundance of mRNA were previously described (47). Primers for human PPAR␥1 (NM138711) and PPAR␥ 2 (NM015869) mRNA were 5Ј-AAAGAAGCCGA-CACTAAACC-3Ј (sense) and 5Ј-CTTCCATTACGGAGA-GATCC-3Ј (antisense) and 5Ј-GCGATTCCTTCACTGA-TAC-3Ј (sense) and 5Ј-CTTCCATTACGGAGAGATCC-3Ј (antisense), respectively.…”

Divergent Sp1 Protein Levels May Underlie Differential Expression of UDP-Glucose Dehydrogenase by Fibroblasts

“…A recent report suggests that the thyrotropin receptor, the central self-antigen in Graves disease, might drive hyaluronan synthesis in orbital fibroblasts (67). Another report suggests that prostaglandin D 2 can up-regulate hyaluronan synthesis in orbital fibroblasts through the D prostanoid receptor, an induction that is attributable to HAS2 activity (68). IL-1␤ induces HAS 1, 2, and 3 mRNA levels (26) as well as UGDH expression (6) in orbital fibroblasts.…”