Carbohydrate Histochemistry
Joan Gil in Models of Lung Disease, 2020
Highly specialized cells line the airways and alveoli of the adult respiratory tract. These cells produce diverse GCs that form the glycocalyx at the cell’s surface. We have little knowledge about the structure of GCs that form the glycocalyx of respiratory tract epithelial cells, since the glycocalyx of one cell type is not biochemically separable from that of another and glycocalyx GCs cannot be reliably isolated from the more abundant secretory glycoproteins that form the mucous surface coat. Cytochemistry provides advantages over biochemical methods for analyzing cell surface components including (1) revealing differences in the structure of the glycocalyx of histologically different cell types, (2) providing the capacity to show differences in GCs of the apical and the basolateral plasmalemma of a cell, and (3) showing changes in the chemical nature of a given cell’s surface during fetal and postnatal development or resulting from pathological change or experimental manipulation.
Control of the Large Bowel Microflora
Michael J. Hill, Philip D. Marsh in Human Microbial Ecology, 2020
As implied above, infants can only be colonized by the bacteria to which they are exposed, and those organisms that persist are capable of forming relatively permanent communities on the gut mucus surface. Many organisms produce a glycocalyx that acts as an anchor for the organism. Bacteria such as Escherichia coli produce fimbriae that extend from the cell wall and may act as specific adhesions anchoring the cell to the mucus layer. The glycocalyx also provides a local protected environment for bacterial growth, allowing multiplication and helping the formation of microcolonies. The glycocalyxes of several different organisms may intermingle to form a diverse community which is in effect co-operatively attached to the mucosa.28 Thus, for initial colonization, attachment/adhesion must be among the predominant influences. The role of metabolic end products and diet is more important in the later stages of community development.
Scanning Angle Interference Microscopy (SAIM)
Qiu-Xing Jiang in New Techniques for Studying Biomembranes, 2020
Glycocalyx is a sugary film composed of multifunctional glycans and glycoproteins that coat every living cell in our body. The upregulated expression of glycoproteins plays a major role in the development of aggressive, lethal cancers.45 In two recent publications,46,47 SAIM has been used to map changes in the glycocalyx thickness induced by engineering its chemical and physical properties to understand how these sugars spatially configure the machinery of signal transduction. The results of such studies show that a bulky glycocalyx (due to overexpression of bulky glycoproteins) facilitates integrin clustering and by the application of tension, induces alteration in integrins’ state. This explains how a bulky glycocalyx induces metastasis by mechanically modulating the function of cell-surface receptors in tumor cells and it is key to understanding how the spatial configuration of these sugars modifies signaling in the context of cancer.
HYAL1 deficiency attenuates lipopolysaccharide-triggered renal injury and endothelial glycocalyx breakdown in septic AKI in mice
Published in Renal Failure, 2023
Hongxia Xing, Shensen Li, Yongchao Fu, Xin Wan, Annan Zhou, Feifei Cao, Qing Sun, Nana Hu, Mengqing Ma, Wenwen Li, Changchun Cao
As a protective barrier with delicate latticework structure, glycocalyx is located on the luminal surface of vascular endothelium and exerts protective effects on endothelial cells [64]. Endothelial glycocalyx can inhibit intravascular coagulation and regulate leukocyte migration to maintain the permeability of endothelium [65]. Syndecan (a proteoglycan) and hyaluronan (a glyocosaminoglycan) are essential for maintenance of endothelial glycocalyx integrity [66]. The glycocalyx performs important physiological functions by transmission to the endothelial surface and shielding it from access by cellular components in the bloodstream [67]. Sepsis resulted in degradation of the endothelial glycocalyx, which is associated with impaired vascular permeability [11]. In our study, injection of LPS contributed to reduction in syndecan-1 level, and elevation of heparanase-1 level, hyaluronidase activity and hyaluronic acid, all of which were offset by silenced HYAL1. Moreover, kidney endothelium glycocalyx layer in the sham-operated mice remained complete and continuous, while the renal capillary glycocalyx of the LPS-treated mice was not continuous with loose and thin structure. Thus, we concluded that deficiency of HYAL1 protected against LPS-induced renal endothelial glycocalyx degradation in septic AKI in vivo.
Cell membrane-camouflaged PLGA biomimetic system for diverse biomedical application
Published in Drug Delivery, 2022
Jingjing Yan, Weidong Fei, Qianqian Song, Yao Zhu, Na Bu, Li Wang, Mengdan Zhao, Xiaoling Zheng
Erythrocytes or red blood cells (RBCs) are the most numerous blood cells in the systemic circulation. In the last century, researchers have developed RBC-based drug carriers via encapsulation or adsorption onto membranes (Mao et al., 2021). The red blood cell membrane (RBCM) possesses the merits of RBC, especially long circulation time and biocompatibility. The transmembrane protein CD47, which is a self-marker, presents ‘do not eat me’ signals to phagocytes (Oldenborg et al., 2000). Moreover, a dense coat of polysaccharides, called ‘glycocalyx’, exhibits spatial stability and also plays a vital role in immune escape. By harnessing the biocompatibility of RBCM coating on PLGA NPs, the acute inflammatory response of the biomaterial scaffold can be eliminated (Fan et al., 2018). Compared with PEGylation, RBCM derived-NPs have twice the cycle time (39.6 h vs. 15.8 h) (Hu et al., 2011). However, the disadvantages of RBCM coating technology are lack of targeting and weak tissue penetration, which inspired scientists to develop other biofilms.
Vascular endothelial damage in COPD: current functional assessment methods and future perspectives
Published in Expert Review of Respiratory Medicine, 2021
Marieta P. Theodorakopoulou, Dimitra Rafailia Bakaloudi, Konstantina Dipla, Andreas Zafeiridis, Afroditi K. Boutou
Glycocalyx is a complex of proteoglycans and glycolipids covering the endothelial lining and protecting the vessel wall against pathogenic insults in cardiovascular disease [66]. It significantly contributes to transferring shear stress into shear-dependent endothelial responses, resulting in NO release [9]. Its function is assessed by both invasive (i.e. tracer dilution method) and noninvasive techiques [i.e. Orthogonal polarization spectral (OPS) and Sidestream dark field (SDF) imaging] [9]. The first method described to estimate systemic glycocalyx volume was the tracer dilution method [78]; in this, systemic glycocalyx volume is measured using the glycocalyx permeable tracer (i.e. Dextran 40) versus a glycocalyx impermeable tracer (i.e. fluorescein-labeled erythrocytes) [9,78]. The main strength of this technique is the direct estimation of the whole-body glycocalyx volume; however, its application is limited due to its invasive nature and demanding preparations [9].
Related Knowledge Centers
- Bacteria
- Epithelium
- Functional Group
- Glycolipid
- Endothelium
- Glycoprotein
- Circulatory System
- Cell Membrane
- Carbohydrate
- Cell–Cell Recognition