Vascular chondroitin/dermatan sulfate proteoglycans remodeling induced by ApoA- I and natural variants. Probable role in settlement of amyloidosis

EIGUREN, A.C.; FUNEZ, F; BIROCCO, A.M.; ROSÚ, S A.; TRICERRI, M. A.; CALABRESE G

Manchester

Congreso; Matrix Biology Europe Conference; 2018

Matrix Biology society

IntroductionAmyloidosis constitutes a heterogeneous group of diseases involving protein misfolding and deposition of fibrils. 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(IOWA,N-terminal peptide of G26R) of the native proteinwith structural disorder elicit their propensity to suffer misfolding or aggregation. Moreover, amyloidosis due to the protein with the native sequencehas been described as diffuse protein aggregates in atherosclerotic plaques. Our previous reports suggestthat specific interactionsof apoA-I with glycosaminoglycans could elicit its retentionand/or aggregation. Furthermore, recentstudies indicate that protein cores of proteoglycans (PGs)may influence the type and modification patterns of the subsequently attached glycosaminoglycan chains. We hypothesize that mutations in human apoA-I may affect the core protein pattern expression of vascular chondroitin/dermatan sulfate PGs, modulating chemical changes in the glycosylation pattern which elicit extracellular apoA-I aggregation.Materials and MethodsWTapoA-I and the amyloidogenic mutants IOWA and R173P were obtained by molecular biology techniques. Human umbilical vein endothelial cells(HUVEC) were treated with 1.5-50 µg/ml for 24hs.MTT, immunofluorescence of NFκB and zymographic analysis were used to evaluate endothelial activation. PG protein cores were quantified using RT-PCR for decorin, biglycan and versican.ResultsWT, R173Por IOWA (1.5 µg/ml) treatment did not modify cell viability, NFκB nuclear translocation and metalloproteinase-2 and -9 activities.Decorin expression was significantlydecreased by WT and R173P, 10 and 6 folds respectively, when it was compared with no treated cells (control). Whereasbiglycan was increased 4-fold by IOWA variant. And versican expression was only detected after R173P treatment.DiscussionWT and the studied natural variants do not elicit an inflammatory response in our experimental model. Nevertheless,our results indicate substantial modifications in the profile of chondroitin/dermatan sulfate PGs core proteins, depending on the protein or peptide employed. Considering that glycosaminoglycans polymerization and modification by sulfation and epimerization are influenced by the protein core; changes in the profile ofPGs might be involved directly or indirectly in the equilibrium between protein function and citotoxicity.