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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
Members of the 4-transmembrane protein superfamily (TM4), such as CD9, CD63, and CD81, have been colocalized with certain β1 and β3 integrins (107–109). TM4:integrin interaction appears to involve extracellular regions (107). Expression of CD9 on an early B-cell line enhances motility, but not adhesion, of this cell line on Fn and laminin (109). This activity was blocked by antibodies against either CD9 or the β1 integrin subunit, as well as the tyrosine kinase inhibitor herbimycin A. Potential biochemical functions of TM4 proteins might include ion transport or as adapter proteins that can couple to G proteins (107).
Lymphocyte and plasma cell malignancies
Published in Gabriel Virella, Medical Immunology, 2019
Juan Carlos Varela, Gabriel Virella
Bone marrow plasmacytosis with clonal cells ≥60% is rare, but when present carries a very poor prognosis. Bone marrow aspirates show massive infiltration of plasma cells with a more or less mature appearance (Figure 27.7). The clonal nature of multiple myeloma plasma cells is indirectly proven by the detection of a monoclonal protein in the serum and/or urine, but there are phenotypic characteristics of clonal malignant plasma cells that can be detected by flow cytometry and allow a more precise estimate of the numbers of clonal cells. In general, malignant plasma cells do not express some of the markers expressed by normal plasma cells (CD19, CD45) or express them weakly (CD27, CD38, CD81) and express markers not detected or detected in very low levels in normal plasma cells (CD20, CD28, CD56, CD117, CD200). The level of expression of these markers has prognostic implications. For example, normal expression of CD27 in clonal plasma cells has a better prognosis, the opposite being true when CD27 is not expressed. The expression of CD81 in clonal plasma cells is also associated with poor prognosis. In contrast, the expression of CD117 is associated with better prognosis.
Retinal stem cell research
Published in A Peyman MD Gholam, A Meffert MD Stephen, D Conway MD FACS Mandi, Chiasson Trisha, Vitreoretinal Surgical Techniques, 2019
Henry Klassen, Michael J Young, Robert Ritch, Julia E Richards, Teresa Borrάs, Leonard A Levin
CNS stem or progenitor cells also express many less specific markers. These include the intermediate filament protein vimentin, the proliferation marker Ki-67, the cell cycle protein cyclin D1, and various forms of the surface adhesion molecule NCAM (neural cell adhesion molecule, CD56), as well as the surface markers CD9 and CD81, both of which are members of the tetraspanin family of transmembrane proteins.5 While it seems increasingly likely that no single unique marker for NSCs will be identified, the use of multiple positive and negative markers in combination may provide a way around this problem. Undoubtedly, a more comprehensive understanding of cellular transcriptional activity will allow investigators to better resolve the ontogenetic status of cells of interest.
Quantitative proteomic analysis of trypsin-treated extracellular vesicles to identify the real-vesicular proteins
Published in Journal of Extracellular Vesicles, 2020
Dongsic Choi, Gyeongyun Go, Dae-Kyum Kim, Jaewook Lee, Seon-Min Park, Dolores Di Vizio, Yong Song Gho
To validate our quantitative proteomic results, we performed Western blotting analyses against the representative proteins in trypsin-sensitive and trypsin-resistant vesicular proteins (Figure 3(c) and Figure S2). Calnexin and RPL14 as trypsin-sensitive vesicular proteins were undetectable after trypsin treatment but CD81 and GAPDH, which belong to the subgroup of trypsin-resistant vesicular proteins, were not apparently affected by trypsin treatment. These results were also observed in EVs derived from monocytic lymphoma U937 cells and immortalized human dermal microvascular endothelial HMEC-1 cells (Figure 4(a,b) and Figure S3). Although CD81 is the canonical EV marker proteins, it is not expressed in U937 cells [24]. Notably, CD81, GAPDH and actin are categorized as top 100 vesicular proteins that are most frequently identified in EV proteomics of EVpedia [2]. ICAM1, calnexin and RPL14 shows the moderate identification with 45, 58 and 55 identification count from 148 proteomic datasets of EVpedia, respectively.
Exosomal communication by metastatic osteosarcoma cells modulates alveolar macrophages to an M2 tumor-promoting phenotype and inhibits tumoricidal functions
Published in OncoImmunology, 2020
Kerri Wolf-Dennen, Nancy Gordon, Eugenie S. Kleinerman
Monoclonal antibodies were purchased from Abcam (Boston, MA) for Calreticulin (ab92516), HSP90B1 (ab3674), CD9 (ab92726) and Beta-actin (ab8226). A monoclonal antibody for CD81 was purchased from Santa Cruz Biotechnology (sc-166029). For immunoblotting, cells were lysed in RIPA buffer (ChemCruz, sc-24948) contained protease pellet (Roche, 04693159001) while exosomes were lysed in 8 M urea 2.5% SDS buffer contained protease pellet. Protein concentrations were determined using the BCA assay (Pierce, 23225) with BSA as a standard. Thirty micrograms of total cellular or exosomal protein were loaded per lane and separated by SDS-PAGE. After transfer at 4 C, the nitrocellulose membrane (Invitrogen, Carlsbad, CA) was blocked with either 5% nonfat dry milk or 5% BSA in Tris-buffered saline (pH 8.0) prior to the addition of primary antibodies and followed with peroxidase-conjugated anti-mouse IgG or anti-rabbit IgG. Protein bands were detected with using a Bio-Rad Chemi-Doc image station with UV-light box (Hercules, CA). An ELISA kit for mouse IL10 was purchased from R&D Systems (M1000B) and performed per the manufacturer’s instructions. A Bio-Plex Pro™ TGF-β 3-plex Assay (171W4001M) was purchased from Bio-rad Technologies and performed according to the manufacturer’s instructions. A neutralizing TGFB2/1.2 Antibody was purchased from R&D Systems (AF-302-NA) and used at a concentration recommended by the manufacturer.
Extracellular vesicles from bone marrow-derived mesenchymal stromal cells support ex vivo survival of human antibody secreting cells
Published in Journal of Extracellular Vesicles, 2018
Doan C. Nguyen, Holly C. Lewis, Chester Joyner, Vivien Warren, Haopeng Xiao, Haydn T. Kissick, Ronghu Wu, Jacques Galipeau, F. Eun-Hyung Lee
EVs are small membranous spheroids that can be released from a variety of cell types. They feature distinctive tetraspanins at their membrane surface (such as CD9, CD63, and CD81) and transport cargo, including proteins and RNA, over short or long distances. EVs can be secreted from cells as large MVs (100–1000 nm diameter) or as the nanoscale exosomes (30–150 nm diameter) [21]. Larger-sized MVs are released from cells as outpouchings of plasma membrane, whereas exosomes have trafficked through the cell’s multivesicular body, part of the endosomal sorting complex required for transport (ESCRT), which tags, sorts and matures endosomes with the use of membrane-bound Rab GTPases [22]. A variety of reports have explored MSC-derived EVs as an avenue for cell-free cell-based therapy, showing therapeutic efficacy in animal models of liver and heart disease [23,24]. In this study, we demonstrate that MSC-derived EVs indeed provide a cell-free component to recapitulate the marrow niche and a novel mechanism of communication between hematopoietic stroma and ASC, thereby enabling the ex vivo cultures of healthy human PC.