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Cell Components and Function
Published in Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal, Principles of Physiology for the Anaesthetist, 2020
Peter Kam, Ian Power, Michael J. Cousins, Philip J. Siddal
Most cells except for red blood cells have integral membrane proteins that attach to the extracellular matrix or with adhesion molecules on neighbouring cells. These molecules hold the tissue together and permit the transmission of mechanical forces from one cell to another. Some also act as receptors. The integrins are cell-matrix adhesion molecules that link cells to fibronectin or laminin in the extracellular matrix. The cadherins are glycoproteins that mediate Ca-dependent cell–cell adhesion. They bind to a copy of the molecule to cadherins on the other molecule. Intercellular adhesion molecules (ICAMS) are expressed on capillary endothelial cell surfaces that are activated by infection of surrounding tissue. They bind to integrins on white cells and promote their movement to sites of infection. Selectins are carbohydrate binding proteins on endothelial cell membranes that recognize sugars on white blood cell surfaces and form the initial binding, which is strengthened by ICAMs.
Integrins, Integrin Regulators, and the Extracellular Matrix
Published in Bruce S. Bochner, Adhesion Molecules in Allergic Disease, 2020
Stephen W. Hunt, Sirid-Aimée Kellermann, Yoji Shimizu
By necessity, adhesion of a migrating leukocyte to the surrounding ECM is transient and cycling, which might suggest that any integrin-associated intracellular complexes are equally transient. Alternatively, such complexes are constitutively present in a complete or semi-formed state, but require activation signals to be functional. There has been some recent progress in identifying negative regulators of integrin-mediated outside-in signaling.
Host Defense I: Non-specific Immunity
Published in Constantin A. Bona, Francisco A. Bonilla, Textbook of Immunology, 2019
Constantin A. Bona, Francisco A. Bonilla
The largest group of these molecules is the integrin family. Integrins are heterodimeric molecules made up of α and β chains. At least eight α (α1-8), and eight β (β 1–8) chains have been identified to date. Various a chains may pair with various β chains. The combination of these chains is not entirely promiscuous, some a chains pair with only one or a few β chains, and vice-versa; all of the possible combinations are not yet known. The integrins are adhesion molecules/receptors which interact with other cell surface molecules and components of the extracellular matrix. Many (but not all) interact with an Arg-Gly-Asp (RGD) tripeptide motif.
Ultrasound-sensitive cRGD-modified liposomes as a novel drug delivery system
Published in Artificial Cells, Nanomedicine, and Biotechnology, 2022
Nour M. AlSawaftah, Vinod Paul, Doua Kosaji, Leen Khabbaz, Nahid S. Awad, Ghaleb A. Husseini
Currently, a class of proteins referred to as the integrin family is being intensively researched for targeted therapy. Integrins are heterodimeric transmembrane glycoproteins comprised of an α and a β subunit. There are 24 known integrin heterodimers made up of 18 α and 8 β subunits [15]. Integrins play a vital role in cell adhesion, motility, signalling, and survival because they bind to various components of the extracellular matrix (ECM) [15,16]. As far as cancer is concerned, integrins were found to play important roles in cancer progression, neoangiogenesis, and some subtypes have been described to be upregulated on many cancer cells, namely αvβ3, αvβ5, and α5β1 [15,17]. The overexpression of certain integrins on cancer cells can be attributed to the need to meet the elevated demand for nutrients and oxygen needed to maintain the rapid growth of tumours.
Targeting the TGF-β signaling pathway for fibrosis therapy: a patent review (2015–2020)
Published in Expert Opinion on Therapeutic Patents, 2021
Xuanyi Li, Ziang Ding, Zixuan Wu, Yinqiu Xu, Hequan Yao, Kejiang Lin
Related inhibitors were developed by simulating the ligands of integrin in vivo. The leading compounds are shown in Table 1. Prakash, J. from Universiteit Twente designed ligand peptides mimicking domains 9 and 10 of fibronectin (FN), in which AV-3 has specific affinity for integrin α5β1 and inhibited fibroblast activation in a concentration-dependent manner [28]. There are similar dipeptide sequences, D-pro-L-pro or related sequences in the peptide structure, that have been designed by Kessler et al from Technische Universitaet Muenchen. This sequence induces the conformational transition of peptide to convey specific affinity for integrin αVβ8, which is much higher than that of other integrins [29]. Tang et al. from University of California, Oakland screened a peptide ligand targeting integrin αvβ6 from the fluorobenzoyl one beam one compound (OBOC) peptide library [30].
Formation and phenotypic characterization of CD49a, CD49b and CD103 expressing CD8 T cell populations in human metastatic melanoma
Published in OncoImmunology, 2018
Marit M. Melssen, Walter Olson, Nolan A. Wages, Brian J. Capaldo, Ileana S. Mauldin, Adela Mahmutovic, Ciara Hutchison, Cornelis J.M. Melief, Timothy N. Bullock, Victor H. Engelhard, Craig L. Slingluff
Integrins are transmembrane molecules that mediate intercellular interactions as well as interactions between cells and extracellular matrix. The integrins α1 (CD49a), α2 (CD49b) and αE (CD103) bind collagen IV, collagen I and E-cadherin respectively, and are thought to retain lymphocytes in peripheral non-lymphoid tissues.1-6 These retention integrins (RI) are also highly expressed on tumor infiltrating lymphocytes (TILs) compared to circulating lymphocytes.7 CD49a+ and/or CD103+ T cells residing in healthy peripheral tissues have features of tissue resident memory T (TRM) cells. TRM cells remain in the tissue long term and can be rapidly induced to have effector function upon exposure to antigen.8-13 In addition, RI expression on effector T cells in inflammatory diseases, including arthritis and hypersensitivity responses, exacerbates inflammatory pathology.14 This suggests that RI directly or indirectly support effector T cell function. The presence of CD103+ or CD49a+ TILs in the tumor microenvironment (TME) is associated with improved survival in several types of cancer, suggesting CD49a and CD103 may support retention, survival or effector function of T cells in the TME, or that they may mark a T cell subset more effective in anti-tumor immunity.15-21 Little is known about the contribution of CD49b to T cell persistence or efficacy in the TME.