Galectin-1 promotes KSHV-mediated PDGFRA activation on mesenchymal stem cells

GAMBARTE TUDELA, J; GARCÍA, P.A.; CERLIANI, J.P.; RAJAMAHENDRAN, R; BANNOUD, N.; CROCI, D.O.; MASONE, D; RABINOVICH, G.A.

Mar del Plata

Congreso; Reunión anual de la Sociedad Argentina de Investigación Clínica (SAIC); 2019

Sociedad Argentina de Investigación Clínica (SAIC), Sociedad de Farmacología Experimental (SAFE), Sociedad Argentina de Biología (SAB), Sociedad Argentina de Protozoología (SAP), Asociación Argentina de Nanomedicinas (NANOMED-ar)

Galectin-1(Gal-1) contributes to tumor immune-scape by inducing apoptosis in Tcells, promoting tolerogenic dendritic cells and favoringangiogenesis by binding glycoepitopes on VEGFR2 in endothelial cells.Kaposi Sarcoma (KS) is characterized by the proliferation of spindlecells and deregulated angiogenesis.Recentreports have shown that KSHV usurps sarcomagenic PDGFRA signaling todrive KS. Thisstudy aimed to investigate the influence of Gal1-N-glycaninteractions in KSHV-mediated sarcomagenic signaling of PDGFRA.Toaddress this, wefirst differentiate bone marrow-derived MSC from B6 mice (CD105+,CD140b+,SCA-1+,CD90.1+,CD11b+,CD34-,CD45-,CD31-,and MHC-II-)and explore their glycophenotype by using a panel of biotinylatedlectins (SNA,PNA, HPA, PHA-L, LEL, ConA, ECL, PHA-E).mMSC exhibited high levels of complexN-glycanswith polylactosamine elongations evidencing permissive glycoepitopesfor Gal-1 binding (P<0.05). In this sense, PE-conjugated rGal-1bound to primary-differentiated mMSC and OP9 cells (a murine MSCline) in a dose and carbohydrate-dependent manner (p<0.05).Moreover, colocalization analysis revealed that Gal-1 interacteddirectly with PDGFRA and more important, with phosphorylated PDGFRAsuggesting that this lectin could bind and activate PDGFRA in MSCs.To better define the role of Gal1 in PDGFRA activation and signaling,we performed WB analysis of mMSCs and OP9 cells incubated with rGal-1(0,5-3 uM; 5-40 min). Our results have shown that Gal-1 activatesPDGFRA signaling inducing Akt, Erk, and STAT-3 phosphorylation(p<0,05). In a bioinformatic approach, we simulate PDGFRA dynamicsin amodel plasma membranein the presence of dimeric Gal-1. Preliminary data of coordinationanalysis showedthat after 250 ns Gal-1 and PDGFRA appear associated in a stablecomplex that affects the lipidic composition of the membrane,suggesting that this interaction could be mediated by lipid raft.Finally,in order to determine whether KSHV could increase Gal1-mediatedPDGFRA signaling, we evaluated the glycan profile of mMSCstransfected with vGCPR (one of the virus gene activated in late KSHVinfection). We observed increasing exposure of glycostructurespermissive for Gal-1 binding on mMSC transfected cells (p<0.05),which it was associated with higher binding of this lectin (p<0.05).Taken together, these data support the hypothesisthat KSHV infection of MSCs could increase oncogenic signaling ofPDGFRA trough a Gal-1-Glycan dependent mechanism promotingvirally-induced sarcomatogenesis.p { margin-bottom: 0.25cm; direction: ltr; color: rgb(0, 0, 0); line-height: 115%; text-align: left; }p.western { font-family: "Cambria", serif; font-size: 12pt; }p.cjk { font-family: "&#65325;&#65331; &#26126;&#26397;"; font-size: 12pt; }p.ctl { font-size: 12pt; }