We next investigated the molecular mechanism by which cyclic stretch upregulates COX-2 mRNA expression. Cyclic stretch did not alter the decay in levels of mRNA following treatment with actinomycin D (Fig. 2A), indicating no change in mRNA stability. Pretreatment of HUVECs with cycloheximide also did not inhibit stretch-induced COX-2 mRNA upregulation (Fig. 2B), indicating that
GW 0742 new protein synthesis is not required. Given that nuclear factor kappa-β (NF-κβ) signaling has recently been recognized as an important modulator of COX-2 gene
expression [10], [11] and [20], we investigated whether NF-κβ signaling mediates COX-2 mRNA upregulation by cyclic stretch. Treatment of HUVECs with parthenolide, a soluble sesquiterpene lactone inhibitor of NF-κβ activation, prevented both stretch-induced NF-κβ activation (Fig. 2C left panel) and COX-2 mRNA upregulation (Fig. 2C right panel), indicating that cyclic stretch stimulates COX-2 mRNA expression via a mechanism that is dependent on NF-κβ signaling.
