Search

Low-temperature plasma is useful for the care of wounded skin. It accelerates wound healing. However, the mechanism of this effect has not been fully elucidated yet. Galectin-1 is reported to accelerate wound healing via the Smad signaling pathway. In the present study to clarify whether or not galectins were expressed during the process of wound healing in the plasma-treated skin, we examined the effect of low-temperature plasma on galectin expression in the healing skin. We compared the effects of low-temperature plasma on the expression of galectin-1, -2, and -3 in the healing skin with those of electrocoagulation conducted with a high-frequency electrical coagulator. Immediately after the start of low-temperature plasma treatment following the incision made in the skin, a membrane-like structure was formed on the surface of the wound. Immunoelectron microscopy showed that these galectins were localized in the membrane-like structure of the plasma-treated skin. The expressions of these galectins were increased by the low-temperature plasma treatment, whereas they were inhibited by the electrocoagulation. These results suggest that galectins were involved in the wound healing of low-temperature plasma-treated skin. Galectins will thus be good markers for further examination of the effects of low-temperature plasma on the healing of wounded skin., (Copyright © 2016 Elsevier Inc. All rights reserved.)

Introduction: Galectin 2 (gal-2) belongs to the proto type group and consists of two homologous carbohydrate recognition domains (CRDs) resulting in multiple sugar binding sites. The expression of gal-2 has been shown to be involved in processes of angiogenesis and inflammation but was not analyzed before in preeclamptic (PE) placentas. Therefore the aim of this study was an analysis of expression and localization of gal-2 in placentas from patients suffering from PE., Methods: Placental tissues were obtained from 14 women following a normal course of pregnancy and 13 women with PE. Expression of gal-2 was evaluated with immunohistochemistry and a semi quantitative score. Gal-2 mRNA expression was quantified in placental tissue using real time TaqMan PCR. Identification of gal-2 expressing cells in the decidua was achieved by double immunofluorescence microscopy., Results: Expression of gal-2 is downregulated in the syncytiotrophoblast of preeclamptic placentas. Downregulation of gal-2 could also be identified in the decidua of PE patients. These findings on protein level could be supported by the results of TaqMan PCR. Gal-2 is downregulated in PE placentas on mRNA level. Finally, gal-2 expressing cells could be identified as extravillous trophoblast cells in both normal pregnancy and PE., Discussion: Gal-2 was identified as an inhibitor of arteriogenesis in a murine model supposedly via modulation of the monocyte/macrophage population. In PE, both the formation of spiral arteries as well as influx of macrophages are dramatically changed. Therefore we might speculate that disturbed transformation of spiral arteries in PE might correlate with the downregulated gal-2 expression by the trophoblast., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

Galectins are a group of animal lectins characterized by their specificity for β-galactosides. Galectin-2 (Gal-2) is predominantly expressed in the gastrointestinal tract. A proteomic analysis identified Gal-2 as a protein that was S-nitrosylated when mouse gastric mucosal lysates were reacted with S-nitrosoglutathione, a physiologically relevant S-nitrosylating agent. In the present study, recombinant mouse (m)Gal-2 was S-nitrosylated using nitrosocysteine (CysNO), which had no effect on the sugar-binding specificity and dimerization capacity of the protein. On the other hand, mGal-2 oxidation by H2O2 resulted in the loss of sugar-binding ability, while S-nitrosylation prevented H2O2-inducted inactivation, presumably by protecting the Cys residue(s) in the protein. These results suggest that S-nitrosylation by nitric oxides protect Gal-2 from oxidative stress in the gastrointestinal tract., (Copyright © 2015 Elsevier Inc. All rights reserved.)

Monocytes and macrophages link the innate and adaptive immune systems and protect the host from the outside world. In inflammatory disorders their activation leads to tissue damage. Galectins have emerged as central regulators of the immune system. However, if they regulate monocyte/macrophage physiology is still unknown. Binding of Gal-1, Gal-2, Gal-3 and Gal-4 to monocytes/macrophages, activation, cytokine secretion and apoptosis were determined by FACS, migration by Transwell system and phagocytosis by phagotest. Supernatants from macrophages co-cultured with galectins revealed their influence on T-cell function. In our study Gal-1, Gal-2, Gal-4, and partly Gal-3 bound to monocytes/macrophages. Galectins prevented Salmonella-induced MHCII upregulation. Cytokine release was distinctly induced by different galectins. T-cell activation was significantly restricted by supernatants of macrophages co-cultured in the presence of Gal-2 or Gal-4. Furthermore, all galectins tested significantly inhibited monocyte migration. Finally, we showed for the first time that galectins induce potently monocyte, but not macrophage apoptosis. Our study provides evidence that galectins distinctively modulate central monocyte/macrophage function. By inhibiting T-cell function via macrophage priming, we show that galectins link the innate and adaptive immune systems and provide new insights into the action of sugar-binding proteins., (Copyright © 2011 Elsevier Inc. All rights reserved.)

Recent advances in genome sequencing efforts have revealed an abundance of novel putative lectins. Among these, many galectin-related proteins, characterized by many conserved residues but intriguingly lacking critical amino acids, have been found in all corners of the eukaryotic superkingdom. Here we present a structural and biochemical analysis of one representative, the galectin-related lectin CGL3 found in the inky cap mushroom Coprinopsis cinerea. This protein contains all but one conserved residues known to be involved in beta-galactoside binding in galectins. A Trp residue strictly conserved among galectins is changed to an Arg in CGL3 (R81). Accordingly, the galectin-related protein is not able to bind lactose. Screening of a glycan array revealed that CGL3 displays preference for oligomers of beta1-4-linked N-acetyl-glucosamines (chitooligosaccharides) and GalNAc beta 1-4GlcNAc (LacdiNAc). Carbohydrate-binding affinity of this novel lectin was quantified using isothermal titration calorimetry, and its mode of chitooligosaccharide coordination not involving any aromatic amino acid residues was studied by X-ray crystallography. Structural information was used to alter the carbohydrate-binding specificity and substrate affinity of CGL3. The importance of residue R81 in determining the carbohydrate-binding specificity was demonstrated by replacing this Arg with a Trp residue (R81W). This single-amino-acid change led to a lectin that failed to bind chitooligosaccharides but gained lactose binding. Our results demonstrate that, similar to the legume lectin fold, the galectin fold represents a conserved structural framework upon which dramatically altered specificities can be grafted by few alterations in the binding site and that, in consequence, many metazoan galectin-related proteins may represent lectins with novel carbohydrate-binding specificities.