SECMA 1(R), A MITOGENIC HEXAPEPTIDE FROM ULVA-ALGEAE MODULATES THE PRODUCTION OF PROTEOGLYCANS AND GLYCOSAMINOGLYCANS IN HUMAN FORESKIN FIBROBLAST

SECMA 1(R) is a polypeptide purified from a green algeae of the Ulva s pecies by several gel chromatagraphies, showing the following sequence (Glu-Asp-Arg-Leu-Lys-Pro). In order to determine the effect of SECMA 1(R) on human skin fibroblasts extracellular matrix, proteoglycans (PG s) and glycosaminoglycans (GAGs) were assayed after 24 h incubation of 20 day-old foreskin fibroblasts at the 2nd passage. The results revea led that most of [S-35]sulphate was associated with fibroblast membran es, which contained (67%) of the total de novo synthesized sulphated P Gs, in two distinct forms: one hydrophilic (39%), and one hydrophobic (28%). The remaining 'matrix' retained 5% of proteoglycans. The remain ing S-35-label may represent the free label in the cytosol. After 24 h incubation of skin fibroblasts with different concentrations of SECMA 1(R) (2, 4 and 10 mu g/ml), the [S-35]sulphate incorporation into PGs of Salt-extract, sodium deoxycholate (DOC) extract and Guanidine hydr ochloride (GuA-HCl)-extract was increased significantly (P < 0.005) wi th 4 mu g/ml, as compared to untreated control. The most effective con centration (4 mu g/ml) increased the different [S-35]sulphate PGs extr acts (NaCl, DOC and GuA-HCl) by respectively (66; 17 and 75%). The rel ative contents of iduronic and glucuronic acid in the GAG produced by skin fibroblasts were estimated. No effect of SECMA 1(R) on the incorp oration of [S-35]sulphate into Heparan sulphate was found. The incorpo ration of [S-35]sulphate into (chondroitine sulphate + heparan sulphat e) and (chondroitine sulphate + dermatan sulphate) was increased by re spectively 37% and 11% by SECMA 1(R) (4 mu g/ml).