DYNAMICS CHANGES IN ENDOTHELIAL EXTRACELLULAR MATRIX INDUCED BY VERY LOW DENSITY LIPOPROTEIN

Previously we described the vascular extracellular matrix remodeling induced by normal VLDL at physiological levels 1) Particularly, we described the differences in chondroitin sulfate/ dermatan sulfate proteoglycans (CS/DS-PGs) according to the endothelial cell phenotypes. 2) The aim of the present study was to analyze the expression pattern of CS/DS-PGs in the presence of increasing levels of N-VLDL. Human N-VLDL were isolated by ultracentrifugation from healthy volunteers. Human umbilical vein endothelial cells (HlNEC) were obtained and cultured as described by Ulrich- Merzenic. 3) Then, HlNEC were incubated with 0,75 and 100 mcg/mL of lipoprotein for 24 h. Protocols were approved by the Bioethics Committee of the University of Buenos Aires, Argentina. After treatment, CS/DS-PGs were characterized through: 1) PG core protein secretion, specifically decorin, biglycan, and versican analysis by immunoblot; 2) glycosaminoglycans (GAGs) content studied by reverse phase HPLC; 3) the levels of chondroitin N-acetylgalactosaminyltransferase-2 (ChGn-2) and chondroitin-4-0-sulfotransferase-1 (C4ST-1) mRNA by RT-PCR. A significant increase in the protein core of decorin and biglycan was detected after treatment (0 vs 75 and 0 vs 100 mcg/mL N-VLDL,p<0.05, n=3), whereas for versican the increase was only observed at 75 mcg/mL (0 vs 75 mcg/mL N-VLDL,p<O.OOl,n=3). A significant increase in CS and DS chains was detected at both levels of N-VLDL (38.5±15.0; 388.0±20.0 and 82.5±50.0 ng/mL; 0, 75 and 100 mcg/mL N-VLDL,p<0.05, n=3), accompanied by an increase in the sulfation ratio 4S/0S of CS and DS chains (4.88±0.13; 13.97±1.8; 14.53±11.46; 0, 75 y 100 mcg/mL, n=3). No differences were observed in ChGn-2 and C4ST-1. At physiological levels, VLDL induced a CS/DS-PG secretion pattern that may contribute to the atheroprotective properties of this endothelial phenotype; such characteristics were lost in the presence of higher levels of the lipoprotein. Our results highlight the importance of CS/DS PGs as a new target for atherosclerosis treatment, Bibliografia 1. Oberkersch R, Rasente Y, Barakian B., Yuschak S., Volpi N., Calabrese G. Extracellular matrix remodeling of endothelial cell was induced by very low density lipoproteins through NFKB activation. 28° Congresso Nazionale della Societa ltaliana per 10 Studio dell'Arteriosclerosi. Roma, Italia. November 23·25, 2014. . 2. Oberkersch R, Rasente Y, Gualco L, Yuschak S, Calabrese G. Very low density lipoproteins induce differential vascular extracellular remodeling according to the endothelial phenotype. Angiogenesis and Leukocytes Atherosclerosis. Geneve, Switzerland. January 30-31, 2014. 3. Ulrich-Merzenich G, Metzner C, Bhonde R, MaIsch G, Schiermeyer B, Vetter H. Simultaneous isolation of endothelial and smooth muscle cells from human umbilical artery or vein and their growth response to low-density lipoproteins.