Vascular biology
Abstract
The hallmark of early atherosclerosis is the accumulation of lipid-laden macrophages in the subendothelial space. Circulating monocytes are the precursors of these “foam cells,” and recent evidence suggests that chemokines play important roles in directing monocyte migration from the blood to the vessel wall. Fractalkine (FK) is a structurally unusual chemokine that can act either as a soluble chemotactic factor or as a transmembrane-anchored adhesion receptor for circulating leukocytes. A polymorphism in the FK receptor, CX3CR1, has been linked to a decrease in the incidence of coronary artery disease. To determine whether FK is critically involved in atherogenesis, we deleted the gene for CX3CR1 and crossed these mice into the apoE–/– background. Here we report that FK is robustly expressed in lesional smooth muscle cells, but not macrophages, in apoE–/– mice on a high-fat diet. CX3CR1–/– mice have a significant reduction in macrophage recruitment to the vessel wall and decreased atherosclerotic lesion formation. Taken together, these data provide strong evidence that FK plays a key role in atherogenesis.
Authors
Philippe Lesnik, Christopher A. Haskell, Israel F. Charo
Abstract
The adhesion receptors known as integrins perform key functions for hematopoietic cells. The platelet integrin αIIbβ3 is critical in hemostasis, and the β1 and β2 integrins on leukocytes have many roles in cell-mediated immunity. Mutations in the β2 subunit lead to integrin nonexpression and to an immune deficiency, leukocyte adhesion deficiency-1. Mutations in either the α or β subunit of αIIbβ3 usually lead to integrin nonexpression and a bleeding tendency termed Glanzmann thrombasthenia. Here we describe a unique patient with clinical features of both Glanzmann thrombasthenia and leukocyte adhesion deficiency-1. The patient has normal expression of β1, β2, and β3 integrins, but all are dysfunctional. The key findings are that “inside-out” signaling pathways leading to integrin activation are defective and that this is associated with abnormal integrin clustering. The integrins themselves are intact and capable of function following extracellular stimulation. T cell motility is normal, as are the expression levels and electrophoretic characteristics of all cytoskeletal and signaling proteins tested, except PKC-α, which has enhanced expression in the patient’s cells. To our knowledge, this is the first description of a dysfunction affecting three classes of integrins. We propose that it is caused by a lesion in an intracellular factor or signaling pathway essential for integrin activation in hematopoietic cells and results in lack of regulation of clustering, an essential component of integrin-mediated adhesion.
Authors
Alison McDowall, David Inwald, Birgit Leitinger, Alison Jones, Ri Liesner, Nigel Klein, Nancy Hogg
Abstract
Research Article
Authors
Florian P. Limbourg, Zhihong Huang, Jean-Christophe Plumier, Tommaso Simoncini, Masayuki Fujioka, Jan Tuckermann, Günther Schütz, Michael A. Moskowitz, James K. Liao
Abstract
Research Article
Authors
Carmen M. Swaisgood, Detlef Schmitt, Dan Eaton, Edward F. Plow
Abstract
Research Article
Authors
Semi Kim, Manjiri Bakre, Hong Yin, Judith A. Varner
Abstract
Research Article
Authors
G. Matthew Longo, Wanfen Xiong, Timothy C. Greiner, Yong Zhao, Nicola Fiotti, B. Timothy Baxter
Abstract
Research Article
Authors
Lingyun Wu, Kun Cao, Yanjie Lu, Rui Wang
Abstract
Research Article
Authors
Christopher Heeschen, Michael Weis, Alexandra Aicher, Stefanie Dimmeler, John P. Cooke
Abstract
Research Article
Authors
Charles D. Loftin, Darshini B. Trivedi, Robert Langenbach
Abstract
Research Article
Authors
Masanori Ozaki, Seinosuke Kawashima, Tomoya Yamashita, Tetsuaki Hirase, Masayuki Namiki, Nobutaka Inoue, Ken-ichi Hirata, Hiroyuki Yasui, Hiromu Sakurai, Yuichi Yoshida, Masahiro Masada, Mitsuhiro Yokoyama
Copyright © 2020 American Society for Clinical Investigation
ISSN: 0021-9738 (print), 1558-8238 (online)