Selective regulation of B-cell subpopulation survival by Galectin-1 and its ligands.

MANSELLE COCCO, MONTANA; MARTINEZ ALLO, VERONICA; CUTINE, ANABELA; SARBIA, NICOLAS; MARIÑO, KARINA; RABINOVICH, GABRIEL A.; TOSCANO, MARTA A

Villa General Belgrano, Cordoba

Simposio; Segundo Simposio Argentino de Glicobiología GlycoAr 2016; 2016

IBYME/ CIQUIBIC/ Fundacion Leloir

Galectin-1 (Gal1), a member of the galectin family of glycan-binding proteins, has shown to be a key regulator of the biology of immune cells. Here, we studied the role of Gal1 and its interaction with specific glycans in the survival B cells. We have previously observed that recombinant Gal1 reduces B cell survival and induced B cell apoptosis in vitro. Since Gal1 binds to N-acetyllactosamine residues in complex N-glycans and O-glycans, we next studied the susceptibility to Gal1 of B cells from mice deficient in specific glycosyltransferases. Surprisingly, we found that N-acetylglucosaminyltransferase 5 (Mgat5-/-) and core 2 glycosyltransferase 1 (C2GnT1-/-) deficient B cells were susceptible to Gal1-binding and induced apoptosis, in a similar extent to WT B cells. However, alpha-2,6-sialyltransferase 1 deficient B cells (St6gal1-/-) showed an increased susceptibility to cell death in the presence of Gal1, indicating that sialic acid in α2,6 position protects B cells from Gal1-induced apoptosis. Furthermore, we studied the glycosylation and Gal1-induced apoptosis in different subpopulations of B cells. We found that transitional-1 and the marginal zone B cells presented a more permissive phenotype to Gal1 binding. These results were reflected in the susceptibility of these B cells subpopulations to Gal1-induced apoptosis. Our findings suggest that Gal1-glycan interactions may have a strategic role in the B cell maturation process in spleen.