HUMAN APO A-I AND ITS NATURAL VARIANTS INDUCE DIFFERENT ENDOTHELIAL CHONDROITIN/ DERMATAN SULFATE PROTEOGLYCAN PROFILE. PROBABLE ROLE IN SETTLEMENT OF AMYLOIDOSIS

EIGUREN, AC; BIROCCO, AM; ROSU, S. A; TRICERRI, M. A.; CALABRESE, GRACIELA C.

Mar del Plata

Encuentro; REUNION CONJUNTA SAIC SAI SAFIS 2018; 2018

SAIC. SAI SAFIS

Apolipoprotein A-I (apoA-I), the main protein of plasma high-density lipoproteins (HDL), removes excess cell cholesterol and protects against atherosclerosis. Nevertheless, some natural variants (R173P) or their N-terminal fragments (G26R 1-93, IOWA) elicit their propensity to suffer misfolding or aggregation. Moreover, amyloidosis due to apoA-I with the native sequence (Wt) has been described deposited in atherosclerotic plaques. We studied the expression of vascular chondroitin/dermatan sulfate proteoglycan (CS/DS-PGs) in the presence of human apoA-I variants to understand whether chemical changes in the glycosylation pattern could elicit extracellular apoA-I aggregation. WT apoA-I, IOWA and R173P were obtained by molecular biology techniques. Human umbilical vein endothelial cells (HUVEC) were treated with 1.5µg/ml for 24hs. Immunofluorescence of NFκB and zymographic analysis were used to evaluate endothelial activation. The proteoglycan protein cores (PG), and the main enzymes involved in CS/DS synthesis were quantified using RT-PCR. WT, R173P or IOWA treatment did not modify NFκB nuclear translocation and metalloproteinase-2 and -9 activities. Decorin expression was significantly decreased by WT and R173P, 10 and 6 folds respectively, when it was compared with control. Whereas biglycan was increased 4-fold by G26R 1-93, IOWA variant, versican expression was only detected after R173P treatment. Dermatan-4-O-Sulfotransferase1 (D4ST) expression decreased 2-fold by Wt, and 10 fold by G26R 1-93, IOWA. While Chrondoitin-4-O-Sulfotransferase1 (C4ST) expression was 5-fold reduced by Wt Dermatan Sulfate Epimerase 1/2 (DS-Epi) decreased 10-fold after R173P treatment and 3-fold after incubation with Wt and G26R 1-93, IOWA. Our results indicate that apoA-I variants induced substantial modifications in the profile of CS/DS-PGs protein cores without inflammation. These modifications were associated with changes in the expression pattern of the enzymes related to glycosaminoglycans synthesis. In conclusion, glycosaminoglycans polymerization, sulfation and epimerization are influenced by the protein core, modulating the characteristics of the Gagosome components. Changes in PG profile, induced by human apoA-I variants, might be involved directly or indirectly in the apoA-I variants citotoxicity.