Shaping hematopoietic cell ecosystems through galectin-glycan interactions

Abstract

Hematopoiesis- the formation of blood cell components- continually replenishes the blood system during embryonicdevelopment and postnatal lifespans. This coordinated process requires the synchronized action of abroad range of cell surface associated proteins and soluble mediators, including growth factors, cytokines andlectins. Collectively, these mediators control cellular communication, signalling, commitment, proliferation,survival and differentiation. Here we discuss the role of galectins – an evolutionarily conserved family of glycanbindingproteins – in the establishment and dynamic remodelling of hematopoietic niches. We focus on thecontribution of galectins to B and T lymphocyte development and selection, as well as studies highlighting therole of these proteins in myelopoiesis, with particular emphasis on erythropoiesis and megakaryopoiesis. Finally,we also highlight recent findings suggesting the role of galectin-1, a prototype member of this protein family, as akey pathogenic factor and therapeutic target in myelofibrosis. Through extracellular or intracellular mechanisms,galectins can influence the fate and function of distinct hematopoietic progenitors and fine-tune the finalrepertoire of blood cells, with critical implications in a wide range of physiologically vital processes includinginnate and adaptive immunity, immune tolerance programs, tissue repair, regeneration, angiogenesis, inflammation,coagulation and oxygen delivery. Additionally, positive or negative regulation of galectin-driven circuitsmay contribute to a broad range of blood cell disorders.