Cell Structure and Functions
Malgorzata Lekka in Cellular Analysis by Atomic Force Microscopy, 2017
Glycolipids form the second group of lipids. They have covalently bound mono- or polysaccharides in the hydrophilic region (through glycosidic bonds). The most common saccharides molecules are galactose, glucose or lactose [1, 2]. Glycolipids can be found in lipid membranes of various organs like brain, nerve system, spleen, kidney, lung, liver, and erythrocytes. Analogously as phospholipids, glycolipids have amphipathic character (Fig. 2.7a). There are several sub-families of glycolipids such as glycosphingolipids, commonly found in nerve tissue, made up of ceramides connected to a carbohydrate moiety. Galactocerebroside (Fig. 2.7b) is a type of glycolipid that is commonly found in the myelin sheath around the nerves of vertebrates.
From cells to systems
Nick Draper, Helen Marshall in Exercise Physiology, 2014
The carbohydrate components of the plasma membrane serve three main purposes: cell recognition, binding of cells to one another and lubrication of the cell surface. Glycoproteins are involved in cell–cell interactions as they serve as part of the identity structure of recognition proteins, for example, they are important in white blood cell and antibody recognition. Glycolipids extend into the extracellular environment where they also act as recognition sites for specific chemicals, in addition to helping cells to attach to one another to form tissues and to decrease friction on the outer surface of the plasma membrane. For cells such as erythrocytes, low friction levels are essential to assist their passage through the narrow constrictions within capillaries.
Peripheral Autonomic Neuropathies
David Robertson, Italo Biaggioni in Disorders of the Autonomic Nervous System, 2019
Fabry disease is characterized by cell storage of glycolipid ceramide trihexoside within the nervous system, including neurons of the autonomic nervous system, and a dying-back neuropathy, most prominent in small myelinated and unmyelinated fibres. Autonomic dysfunction has been demonstrated in this disease (Cable, Kolodny and Adams, 1980). Nine males with the disorder were examined and showed impaired sweating, absent corrugation of the skin induced by warm water immersion (a sign of autonomic denervation), and an abnormal flare component of the triple response of Lewis. Abnormal pupillary responses to pilocarpine, reduced saliva production, tear formation and abnormal cardiovascular responses, including decreased reflex rises in plasma noradrenaline, were also present. Sympathetic and parasympathetic function was impaired and was thought to represent small nerve fibre dysfunction in peripheral nerves. Autonomic nervous system involvement is rarely as incapacitating in this disease as in acute pandysautonomia.
Surface-modified polymeric nanoparticles for drug delivery to cancer cells
Published in Expert Opinion on Drug Delivery, 2021
Arsalan Ahmed, Shumaila Sarwar, Yong Hu, Muhammad Usman Munir, Muhammad Farrukh Nisar, Fakhera Ikram, Anila Asif, Saeed Ur Rahman, Aqif Anwar Chaudhry, Ihtasham Ur Rehman
Cell membrane functions as the main barrier for inward and outward movement of bio-entities [33]. Similarly, drug-loaded polymeric nanoparticles are also needed to cross the cell membrane to exhibit their efficiency. The composition, morphology, and functions of cell membrane have attracted scientists to fabricate nanoparticles, whose surfaces mimic cell membrane (Figure 3a). The cell membrane is composed of a phospholipid bilayer with embedded proteins and carbohydrates. Phospholipids consist of hydrophobic phosphate group-containing head linked to the hydrophobic tail of fatty acids. These phospholipids self-assemble into bilayers with hydrophilic regions facing toward outside and inside of the cell, while hydrophobic tails of phospholipids face each other. The incorporation of cholesterol and proteins enhances the stability of the cell membrane. Membrane proteins are inserted throughout the cell membrane asymmetrically. They are arranged in a way that their exterior surfaces can act as receptors for signaling molecules, whereas interior sides change their conformation in response to the binding signal. In some cases, membrane carbohydrates, in the form of glycolipids, work as recognition sites for proteins [34]. Research on biologically inspired nanoparticles has revealed that surface modification of nanoparticles with lipid bilayer or protein/carbohydrate embedding enhances the efficacy of drug-loaded nanoparticles [35], for instance increase in circulation time, improved biocompatibility, low toxicity and immunogenicity [36] and enhanced stability [37].
Visual Function in Mice Lacking GM3 Synthase
Published in Current Eye Research, 2019
Miki Hiraoka, Ei Ohkawa, Akira Abe, Masaki Murata, Shinji Go, Jin-ichi Inokuchi, Hiroshi Ohguro
The Individual neutral lipid fractions obtained in the ganglioside analysis section were dissolved with 500 µl of chloroform and 1 ml of 0.21 N NaOH in methanol, and incubated for 1 h at 37°C. The reaction was terminated by the addition of 1 ml of 0.2 N HCl. After centrifugation at 1,000 g for 5 min at 25°C, the organic phase was transferred into a glass tube and mixed with 2 ml of methanol plus 800 µl of 0.05 N HCl containing 25 mM HgCl2. The reaction mixture was incubated for 20 min at 37°C and mixed with 1 ml of chloroform plus 1.2 ml of water. After centrifugation at 1,000 g for 5 min, the organic phase was washed with 1 ml of methanol and 800 µl of 33.3 mM EDTA and then washed twice with 1 ml of methanol plus 800 µl of 0.9% (w/v) of NaCl. The resultant organic phase was transferred into another glass tube, dried by N2 gas and applied to an HPTLC plate. Glycolipids were detected as described in the ganglioside analysis section.
Nanovaccine administration route is critical to obtain pertinent iNKt cell help for robust anti-tumor T and B cell responses
Published in OncoImmunology, 2020
Yusuf Dölen, Michael Valente, Oya Tagit, Eliezer Jäger, Eric A. W. Van Dinther, N. Koen van Riessen, Martin Hruby, Uzi Gileadi, Vincenzo Cerundolo, Carl G. Figdor
iNKT cells comprise a subset of T cells that share both NK cell characteristics and bear an invariant αβ T cell receptor. Instead of protein peptides that are recognized by regular T cells, iNKT cells recognize glycolipids presented by MHC Class I like molecule CD1d. In particular, microorganism-derived glycolipids that contain a sugar α-linked to a lipid tail are amongst the strongest TCR binding antigens.1 iNKT cells can be divided into further subsets based on their cytokine secretion profile: iNKT1 cells are the only producers of IFN-y, iNKT2 cells mainly produce IL-4 and iNKT17 cells are the sole producers of IL-17.2 iNKT cells have been considered as a potential tool in cancer immunotherapy, making use of their ability to either directly kill tumor cells or to activate NK cells via IFN-y and IL-21 secretion.3,4 Furthermore, it has been demonstrated that iNKT cells exert a strong helper function by the secretion of cytokines to generate robust CD8+ T cell responses.5 Therefore, α-galactosylceramide (α-GalCer) and its analogs thereof have been widely explored as vaccine adjuvants to boost T cell responses.6 In this study, we used IMM60 as an iNKT cell agonist as it was shown to have a higher affinity to human iNKT-cell TCR than α-GalCer and results in extended responses both in human and mouse iNKT cells7
Related Knowledge Centers
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- Cell Membrane
- Lipid
- Carbohydrate
- Cell
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