Galectins in Invertebrates with a focus on <i>Caenorhabditis elegans</i>

Abstract

Galectins are a family of β-galactoside-binding lectins widely distributed among animals and fungi, and Galβ1-4GlcNAc is considered the major recognition unit of vertebrate galectins. On the other hand, more than 10 galectins have been reported in Caenorhabditis elegans that belong to the invertebrate class and these C. elegans galectins have been confirmed to have affinity for Galβ1-4GlcNAc. However, the glycan structure differs among species and glycan containing Galβ1-4GlcNAc has not been reported in C. elegans so far. Therefore, the endogenous ligands of C. elegans galectins remained undetermined. Recent studies uncovered that the structures of endogenous ligand glycans of C. elegans galectins are different from those of vertebrate galectins, for e.g., Nglycan containing Galactoseβ1-4 fucose epitope which is not found in vertebrates. Further, C. elegans galectins play a role in host defense against infection and oxidative stress. The roles of mammalian galectins in host defense have been explored in recent years. Taken together, one of the fundamental functions of galectins is possibly host defense because both C. elegans and mammalian galectins function in host defense despite alterations of their ligand structure in the evolutionary process. A. IntroductionGalectins are a family of widely distributed animal lectins that specifically bind to β-galactoside sugars such as Galβ1-4Glc and shown to function in various biological phenomena such as development, cancer, and immunity, and Galβ1-4GlcNAc is thought to be the major endogenous recognition unit of vertebrate galectins (5-8). Meanwhile, in recent years, the recognition of exogenous glycans by galectin is also thought to be important for innate immunity (3, 6), and it has been shown that galectins have affinities for various disaccharide units that contain β-galactoside structure regardless of whether such disaccharides are found endogenously or exogenously (9). B. Galectin (-like) Proteins in InvertebratesNumerous galectin (-like) proteins have also been found in

Nanoparticles To Study Lectins in Caenorhabditis elegans: Multivalent Galactose β1-4 Fucose-Functionalized Dendrimers Provide Protection from Oxidative Stress

“…Most research on nematode galectins has focused on the model organism Caenorhabditis elegans 21 in which 12 members of the C. elegans galectin protein family have been isolated and purified. 1,22 LEC-6 and LEC-12 are the prototype galectins in C. elegans (Figure 1a); LEC-1, LEC-2, LEC-3, LEC-4, and LEC-5 are the tandem-repeat galectins in C. elegans (Figure 1b); and LEC-7, LEC-8, LEC-9, LEC-10, and LEC-11 are the chimera galectins in this species (Figure 1c). Although N-acetyllactosamine (Galβ1-4GlcNAc) binds to the C. elegans' galectins, endogenously they lack this disaccharide unit.…”

“…Most research on nematode galectins has focused on the model organism Caenorhabditis elegans in which 12 members of the C. elegans galectin protein family have been isolated and purified. , LEC-6 and LEC-12 are the prototype galectins in C. elegans (Figure a); LEC-1, LEC-2, LEC-3, LEC-4, and LEC-5 are the tandem-repeat galectins in C.…”

“…elegans lacking galectins have been reported to be hypersusceptible to oxidative stress but otherwise develop normally under standard laboratory conditions . For example, lec-1 and lec-10 mutants are more susceptible to stress conditions such as infection and oxidation. , These results suggest that galectins are important to the host defense system, although the mechanisms of action are not known. ,, Similarly, in humans, galectin-3 has recently been proposed to play an important role in inflammation caused by oxidative stress during disease states such as diabetes . To study the in vivo effects of multivalency of galectins, Galβ1-4Fuc-functionalized dendrimers were synthesized and subsequently administered to C.…”

“…34 Previously, C. elegans lacking galectins have been reported to be hypersusceptible to oxidative stress but otherwise develop normally under standard laboratory conditions. 22 For example, lec-1 and lec-10 mutants are more susceptible to stress conditions such as infection and oxidation. 31,35 These results suggest that galectins are important to the host defense system, although the mechanisms of action are not known.…”

Novos aspectos do efeito antibacteriano de galectinas ligantes de lipopolissacarídeo

“…Se isso for verdade, as galectinas poderia tanto atuar na resolução de patógenos humanos, como também para o controle de infecções em animais invertebrados que dependem quase que exclusivamente de elementos da imunidade inata (Zhang et al 2020;García-Maldonado, Cano-Sánchez, e Hernández-Santoyo 2017;Sreeramulu et al 2018). Ainda, vale notar que muitos desses organismos apresentam um grande repertório de galectinas (Takeuchi 2018), ressaltando uma importância evolutiva desta família de lectinas nesse contexto.…”