ANTISENSE S-OLIGONUCLEOTIDE AGAINST TRANSFORMING GROWTH FACTOR-BETA(1), INHIBITS PROTEOGLYCAN SYNTHESIS IN ARTERIAL-WALL

Transforming growth factor-beta(1) (TGF-beta(1)) is a potent stimulator of proteoglycan (PG) synthesis by cultured smooth muscle cells. To test the hypothesis that TGF-beta(1) stimulates PG synthesis in whole artery wall we have investigated the effect of blocking endogenous TGF-beta(1) using an antisense S-oligonucleotide (ASO) directed against the first 7 codons for the N-terminal region of active TGF-beta(1). This sequence reduced TGF-beta(1) secretion by cultured endothelial cells by 40-55%. To determine the effect of the ASO on PG synthesis in whole vessel we chose the rat carotid artery (RCA) maintained in organ culture, a model in which we previously documented endothelial-dependent increases in PG synthesis over time in culture. We report here that the increases in PG in the inner layers of the vessel wall are matched by similar increases in TGF-beta(1) mRNA. To test for the effect of ASO on PG synthesis, small segments of RCA, maintained in organ culture (Medium 199, supplemented with 1% FCS), were exposed on day 6 to either control media, antisense TGF-beta(1), sense TGF-beta(1), or a non-sense sequence at 5, 10 and 20 mu M concentrations. Following 24 h exposure to the oligonucleotides, cultures were labelled for a further 24 h with [H-3]glucosamine and processed for autoradiography. Antisense TGF-beta(1) at 10 and 20 mu M produced a 60% reduction in PG synthesis in the endothelium and adjacent first layer of the media. The remaining medial layers and adventitia were not affected by the ASO. These results are consistent with the hypothesis that TGF-beta(1) plays a role in controlling PG synthesis in the inner wall where lesions develop.