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Epithelial Cells
Published in Bruce S. Bochner, Adhesion Molecules in Allergic Disease, 2020
The desmosome is sometimes referred to as a “spot-weld” between cells (45). Within the pseudostratified morphology of the airway epithelium, desmosomes are present along the lateral aspects of the columnar cells, particularly towards the cell apex, and at the junction between the columnar and basal cells. Ultra-structurally, desmosomes measure between 0.1 and 1.5 μm in diameter and are delineated by an electron-dense plaque and electron-dense filaments that span the intercellular space (46). Anchoring tonofilaments fan out from the plaques into the adjacent cytoplasm. The tonofilaments loop repeatedly from the cytoplasm to the plaque and then back into the cytoplasm (47).
Pemphigus
Published in Lionel Fry, Atlas of Bullous Diseases, 2020
The primary pathological event in pemphigus is the loss of adhesion of the epidermal cells. The attachment of epidermal cells is mainly through the desmosomes, and to a lesser extent by so-called ‘tight’ or ‘adherence’ junctions. The desmosome is made up of structures called Cadherins which are divided into desmogleins and desmocollins. These structures have an intracellular, a transmembrane and an extracellular component. Intracellularly they are attached to the keratin cytoskeleton and extra-cellularly to that of another cell forming the desmosome (Figure 3.2). Desmogleins are subdivided into desmogleins 1, 2 and 3 and are intracellular components of the desmosome (Figure 3.2). Desmoglein 3 is expressed only in the basal and suprabasal layers of the epidermis, whereas desmoglein 1 is expressed throughout the epidermis but mainly in the upper layers. In mucosae, desmoglein 3 is strongly expressed throughout the epithelium and desmoglein 1 only weakly.
The Thymic Defect
Published in Miroslav Holub, Immunology of Nude Mice, 2020
Even today, morphological evidence cannot disprove the possibility predicted by the transformation theory, namely, that thymic epithelial cells can differentiate in thymic lymphoid cells. It is hard to dismiss the occurrence of desmosomes, i.e., sites of very strong attachment developing, usually, between epithelial cells of one kind, which have been found electron microscopically between mouse thymic epithelial cells and lymphoblasts and between lymphoblasts, prior to vascularization of the thymus anlage.48 Without evidence provided by surface markers one must assume that there may be some stroma-derived cell in the mouse and chick thymus which has the ultrastructure of an immature lymphoid cell and may or may not be the precursor of lymphocytes as defined by immunological functions and markers. Such a possibility complicates, of course, the problem of the nude mouse thymic dysgenesis.
The value of desmosomal plaque-related markers to distinguish squamous cell carcinoma and adenocarcinoma of the lung
Published in Upsala Journal of Medical Sciences, 2020
Inmaculada Galindo, Mercedes Gómez-Morales, Inés Díaz-Cano, Álvaro Andrades, Mercedes Caba-Molina, María Teresa Miranda-León, Pedro Pablo Medina, Joel Martín-Padron, María Esther Fárez-Vidal
Desmosomes are cell structures specialized for focal cell-to-cell adhesion that are localized in randomly arranged spots on the lateral sides of plasma membranes. They play an important role in providing strength to tissues under mechanical stress, such as the cardiac muscle and epidermis. Besides the constitutive desmosomal plaque proteins desmoplakin and plakoglobin, at least one of the three classical members of the plakophilin (PKP) family is required to form functional desmosomes (12–14). PKP1 is a major desmosomal plaque component that recruits intermediate filaments to sites of cell–cell contact via interaction with desmoplakin. PKPs regulate cellular processes, including protein synthesis and cell growth, proliferation, and migration, and they have been implicated in tumour development (15–21).
Epithelial maturity influences EPEC-induced desmosomal alterations
Published in Gut Microbes, 2019
Jennifer Lising Roxas, Gayatri Vedantam, V.K. Viswanathan
Desmosomes are protein complexes comprised of desmosomal cadherins, armadillo proteins and plakins, which are stabilized at paracellular junctions by the tethering of intermediate filaments (IF).1 Desmosomes connect the walls of adjacent host cells at multiple discrete regions forming “spot-welds” that provide tensile strength to the cell layer. Much of our current understanding of the formation and maintenance of desmosomes is based on studies on the epidermis and on cardiomyocytes. However, desmosomal plaque composition, as well as spatial organization of cells held together by desmosomes, differ in various tissue types (Figure 1).2–6 In contrast to the stratified epithelial cells of the skin and the branched myocytes of the heart, a single layer of simple columnar epithelial cells blankets the intestinal mucosa. Moreover, while all desmosomal cadherin isoforms are expressed in the skin albeit in different combinations and abundances through the epidermal layers, only desmoglein-2 (DSG2) and desmocolin-2 (DSC2) are found in normal intestinal epithelium and in cardiac muscles.1,5
AMPK in regulation of apical junctions and barrier function of intestinal epithelium
Published in Tissue Barriers, 2018
Mei-Jun Zhu, Xiaofei Sun, Min Du
Epithelial cells are joined by a series of intercellular junctions and polarized into the apical and the basolateral domains.30,31 The apical domain of epithelial cells is linked with adjacent epithelial cells through TJs and AJs, which are also referred to as apical junctions (Fig. 1). The assembly of apical junctions is indispensable for the formation and maintenance of epithelial barrier integrity.1,32 Desmosomes are intercellular junctions located below AJs on the lateral membrane and link to intermediate filaments to stabilize the epithelial layer and provide mechanical strength to tissues.33,34 On the basolateral membrane, hemidesmosomes connect to intermediate filament and facilitate epithelial cell adhesion to extracellular matrix in the basal lamina.35 In addition, epithelial cells communicate with surrounding cells through gap junctions (Fig. 1) that are composed of connexins and assembled into hexameric pore-forming channels.36