Galectin

About: Galectin is a research topic. Over the lifetime, 2076 publications have been published within this topic receiving 103409 citations. The topic is also known as: IPR001079 & Galectin.

Interaction of galectin-9 with lipid rafts induces osteoblast proliferation through the c-Src/ERK signaling pathway.

Abstract: Galectin-9 is a β-galactoside-binding lectin expressed in various tissues, including bone. The role of galectin-9 in human osteoblasts, however, remains unclear. This study showed that galectin-9 interacts with lipid rafts and induces osteoblast proliferation through the c-Src/ERK signaling pathway. Introduction: Galectin-9 is a β-galactoside-binding lectin that modulates many biological functions by interacting with particular carbohydrates attached to proteins and lipids. However, the role of galectin-9 in bone metabolism and osteoblast proliferation remains unclear. This study investigated the effects of galectin-9 on osteoblast proliferation and its signaling mechanisms. Materials and Methods: The effect of galectin-9 on osteoblast proliferation was tested by measuring the conversion of tetrazolium salt WST-8 to formazan. Protein phosphorylation was assayed by western blotting and confocal microscopy was used to localize lipid rafts. Results: Galectin-9–induced proliferation of the obtained osteoblasts in a dose-dependent manner, whereas galectin-1, -3, and -4 did not. Galectin-9–induced phosphorylation of c-Src and subsequent ERK1/ERK2 in the osteoblasts. The galectin-9–induced phosphorylation and proliferation were inhibited by PP2, a selective inhibitor of c-Src. Galectin-9–induced clustering of lipid rafts detected by cholera toxin B (CTB; binding the raft-resident ganglioside GM1) using confocal microscopy. Cross-linking of the GM1 ganglioside with CTB by anti-CTB antibody-induced phosphorylation of c-Src, whereas disruption of galectin-9–induced lipid rafts by β-methylcyclodextrin reduced c-Src phosphorylation and proliferation of the cells. Conclusions: These results suggest that galectin-9, but not other galectins, induced proliferation of human osteoblasts through clustering lipid rafts on membrane and subsequent phosphorylation of the c-Src/ERK signaling pathway.

Functional characterization of an eosinophil-specific galectin, ovine galectin-14

Abstract: Across mammalian species, human galectin-10 and ovine galectin-14 are unique in their expression in eosinophils and their release into lung and gastrointestinal tissues following allergen or parasite challenge. Recombinant galectin-14 is active in carbohydrate binding assays and has been used in this study to unravel the function of this major eosinophil constituent. In vitro cultures revealed that galectin-14 is spontaneously released by eosinophils isolated from allergen-stimulated mammary gland lavage, but not by resting peripheral blood eosinophils. Galectin-14 secretion from peripheral blood eosinophils can be induced by the same stimuli that induce eosinophil degranulation. Flow cytometric analysis showed that recombinant galectin-14 can bind in vitro to eosinophils, neutrophils and activated lymphocytes. Glycan array screening indicated that galectin-14 recognizes terminal N-acetyllactosamine residues which can be modified with α1-2-fucosylation and, uniquely for a galectin, prefers α2- over α2-sialylation. Galectin-14 showed the greatest affinity for lacto-N-neotetraose, an immunomodulatory oligosaccharide expressed by helminths. Galectin-14 binds specifically to laminin in vitro, and to mucus and mucus producing cells on lung and intestinal tissue sections. In vivo, galectin-14 is abundantly present in mucus scrapings collected from either lungs or gastrointestinal tract following allergen or parasite challenge, respectively. These results suggest that in vivo secretion of eosinophil galectins may be specifically induced at epithelial surfaces after recruitment of eosinophils by allergic stimuli, and that eosinophil galectins may be involved in promoting adhesion and changing mucus properties during parasite infection and allergies.

Human galectin-3 selective and high affinity inhibitors. Present state and future perspectives.

Abstract: Over the last decade an increasing number of studies have been published reporting on the inhibitory potency or selectivity that several types of ligands show against human galectin-3 (hGal-3). The reason for this interest lies in the many important roles galectins play both in intra and extra-cellular functions. Among galectins, galectin-3 stands out because it is the only known member of its subfamily in mammals, is small and monomeric but capable of aggregating, and is known to be involved in a large number of disease processes, from cancer to heart failure. These characteristics and roles make hGal-3 an ideal target for drugs. Since it binds β-galactosides, like the rest of the galectin family of proteins, the search and design of potent and at the same time selective inhibitors for it is not an easy task. Herein we discuss the chemical features of the most potent inhibitors described so far, as well as the structural basis of their exhibited selectivity, in order to shed light on the rational design of drugs against this target.