Role of sugars in surface microbe–host interactions and immune reaction modulation

Abstract

Sugars in the form of monosaccharides, oligosaccharides, polysaccharides and glycoconjugates (glycoproteins, glycolipids) are vital components of infecting microbes and host cells, and are involved in cell signalling associated with modulation of inflammation in all integumental structures. Indeed, sugars are the molecules most commonly involved in cell recognition and communication. In skin, they are essential to epidermal development and homeostasis. They play important roles in microbial adherence, colonization and biofilm formation, and in virulence. Two groups of pathogen recognition receptors, C-type lectins (CTL) and their receptors (CTLR), and the Toll-like receptors enable the host to recognize pathogen-associated molecular patterns (PAMPs), which are mainly glycolipids. The CTLs can recognize a wide variety of bacteria, fungi and parasites and are important in phagocytosis and endocytosis. TLRs are expressed on the surfaces of a variety of cells, including keratinocytes, dendritic cells, monocytes and macrophages; they play a major role in innate immunity. Interaction of TLRs with PAMPs initiates a cascade of events leading to production of reactive oxygen intermediates, cytokines and chemokines, and promotes inflammation. Exogenous sugars can block carbohydrate receptors and competitively displace bacteria from attachment to cells, including keratinocytes. Thus sugars may provide valuable adjunctive anti-inflammatory and/or antimicrobial treatment. A promising approach is the use of a panel of carbohydrate derivatives with anti-adhesive efficacy against bacteria frequently involved in diseases affecting skin and other epithelia. More complete characterization of sugar receptors and their ligands will provide further keys to use of carbohydrates in immunomodulation and infection control in skin.

The Effect of Exopolysaccharide-Producing Probiotic Strains on Gut Oxidative Damage in Experimental Colitis

“…EPS is a longchain polysaccharide consisting of branched, repeating units of sugars or sugar derivatives. Indeed, sugars are the molecules most commonly involved in cell recognition and communication [34]. Chemical characteristics of EPS such as charge, nature of the sugar components, and molecular weight influence their biological activity [35].…”

Adamantyl Glycosphingolipids Provide a New Approach to the Selective Regulation of Cellular Glycosphingolipid Metabolism

“…GSLs can modulate membrane receptor function (3,4), are altered in cancer (5,6) and cell growth (7), and provide a primary target for host cell interaction with microbial pathogens (8). In addition, GSL accumulation has been identified to contribute to the pathology of many other diseases, including Parkinson disease (9,10), Alzheimer's disease (11), type 2 diabetes (12,13), growth factor dysregulation (14), polycystic kidney disease (15), atherosclerosis (16) and cystic fibrosis (17).…”

Xylitol inhibits J774A.1 macrophage adhesion in vitro

“…These determinations should also be done with a phlogiston agent, such as LPS, added in the culture medium. The ability of exogenous sugars to block these specific receptors and/or to competitively displace bacteria from their attachment sites on the cells may provide an adjunctive anti-inflammatory and/or antimicrobial treatment (Lloyd et al, 2007). Xylitol used to treat the cells after the infection acted in a non-specific, but satisfactory manner to inhibit the cell adhesion to a surface.…”