gms | German Medical Science

Accumulation of hyaluronic acid (HA) is characteristic for atherosclerotic and restenotic lesions of patients with coronary heart disease. HA, a glycosaminglycan of the extracellular matrix, is synthesized by three HA-synthase (HAS) isoforms, HAS1, HAS2, HAS3. HA regulates a number of fundamental cellular processes such as migration and cell proliferation. However, the functional significance of the individual HAS-isoenzymes is unknown. The aim of the present study was to investigate the function of HAS3 in human arterial smooth muscle cells (SMC). Therefore, specific HAS3-siRNA was used to analyse the effect of HAS3 on migration, proliferation and morphology of SMC. Human arterial SMC were derived from coronary arteries and used between passage 4-10. The cells were cultured in DMEM + 10% FCS ( Fetal Calf Serum) and used at 50-70 % confluency. The cells were transfected with HAS3-siRNA or non-silencing control-siRNA. The experiments were initiated 48h after transfection. HAS3-siRNA reduced HAS3-mRNA levels to 50 ± 22% (n = 4, p<0.05) of control cells. Suppression of HAS3 expression decreased the area occupied by SMC to 59.4 ± 9.2% ( n = 4, p<0.05) of cells treated with control si-RNA. Furthermore, FCS induced migration of SMC was reduced by HAS3-siRNA, as determined by a modified boyden chamber assay (57 ± 8%, n = 3, p< 0.05). Additionally, we examined the effect of HAS3-siRNA on SMC proliferation as assessed by [3H]-thymidine incorporation. HAS3-siRNA transfection inhibited FCS induced DNA synthesis to 63 ± 8% (n = 3, p<0,05) of control cells. These findings demonstrate for the first time that HA synthesized by HAS3 (i) participates in the regulation of cell shape and spreading, (ii) mediates migration and (iii) supports proliferation. These phenotypic characteristics are critical in the development of neointimal hyperplasia and plaque progression. Therefore HAS3 might support the progression of atherosclerosis