Biphasic Effect of Recombinant Galectin‐1 on the Growth and Death of Early Hematopoietic Cells

Abstract

Galectin-1 is a member of the family of β-galactoside binding animal lectins, galectins. Its presence in the bone marrow has been detected; however, its role in the regulation of hematopoiesis is unknown. In the present study, we have evaluated the effect of recombinant human galectin-1 on the proliferation and survival of murine and human hematopoietic stem and progenitor cells. We show that low amount of galectin-1 (10 ng/ml) increases the formation of granulocyte-macrophage and erythroid colonies and the frequencies of day-7 cobblestone area-forming cells on a lactose-inhibitable fashion. In contrast, high amount of galectin-1 (10 μg/ml) dramatically reduces the growth of the committed blood-forming progenitor cells as well as the much younger, lineage-negative hematopoietic cells (day-28 to -35 cobblestone area-forming cells). This inhibition is not blocked by lactose and, therefore, is largely independent of the β-galactoside-binding site of the lectin. Furthermore, assays to detect apoptosis render it likely that the high amount of galectin-1 acts as a classical proapoptotic factor for the premature hematopoietic cells.

A carbohydrate-binding protein, Galectin-1, promotes proliferation of adult neural stem cells

“…In general, lectins exert their biological effects by binding to certain carbohydrate structures. Galectin-1's carbohydrate-binding ability is required for some functions but not others (27,39,51,52). The present study suggests that the carbohydrate-binding activity of Galectin-1 is required for its promotion of adult neural progenitor cell proliferation.…”

“…Carbohydrates on the cell surface may be involved in the intercellular interactions of various stem cells, including NSCs (23)(24)(25) and HSCs (26). A recent report suggested that Galectin-1 promotes the proliferation of HSCs in vitro (27). However, its functions in NSCs remain unknown.…”

Synergistic Induction of Galectin-1 by CCAAT/Enhancer Binding Protein α and Hypoxia-inducible Factor 1α and Its Role in Differentiation of Acute Myeloid Leukemic Cells

“…Upon erythroid differentiation of leukemic K562 cells, the galectin-1 is externalized and bound to the cell surface (10). Also, recombinant galectin-1 can mediate the growth and death of murine and human hematopoietic stem and progenitor cells (11). However, the mechanisms for the molecular regulation of galectin-1 expression in normal and malignant hematopoietic cells remain largely unknown.…”

Galectin-1 Promotes Immunoglobulin Production during Plasma Cell Differentiation

“…In addition to its role in regulating many aspects of T cell function, galectin-1 appears to have a role in stromal cells. Galectin-1 is expressed in bone marrow stromal cells (15,16), and secreted galectin-1 anchors to integrins to interact with pre-BCR and acts as a survival signal for pre-B cells during development (15,17). In late-stage B cell activation and maturation, soluble galectin-1 produced by activated B cells resulting from Trypanosoma cruzi infection in mice causes T cell apoptosis and affects IFN-␥ production (18).…”