Monocytic Cells Synthesize, Adhere to, and Migrate on Laminin-8 (α4β1γ1)

Abstract

Laminins, a growing family of large heterotrimeric proteins with cell adhesive and signaling properties, are major components of vascular and other basement membranes. Expression, recognition, and use of laminin isoforms by leukocytes are poorly understood. In monoblastic THP-1 cells, transcripts for laminin γ1-, β1-, and α4-chains were detected by RT-PCR. Following immunoaffinity purification on a laminin β1 Ab-Sepharose column, laminin β1- (220 kDa), γ1- (200 kDa), and α4- (180/200 kDa) chains were detected by Western blotting in THP-1 cells and in two other monoblastic cell lines, U-937 and Mono Mac 6. After cell permeabilization, a mAb to laminin γ1-chain reacted with practically all blood monocytes by immunofluorescence flow cytometry, and laminin-8 (α4β1γ1) could be isolated also from these cells. Monoblastic JOSK-I cells adhered constitutively to immobilized recombinant laminin-8, less than to laminin-10/11 (α5β1γ1/α5β2γ1) but to a higher level than to laminin-1 (α1β1γ1). Compared with the other laminin isoforms, adhesion to laminin-8 was preferentially mediated by α6β1 and β2 integrins. Laminin-8 and, to a lower extent, laminin-1 promoted spontaneous and chemokine-induced migration of blood monocytes, whereas laminin-10/11 was inhibitory. Altogether, the results indicate that leukocytes, as other cell types, are able to synthesize complete laminin molecules. Expression, recognition, and use of laminin-8 by leukocytes suggest a major role of this laminin isoform in leukocyte physiology.

Relaxin Stimulates Leukocyte Adhesion and Migration through a Relaxin Receptor LGR7-dependent Mechanism

“…To demonstrate the chemokine-like properties of the relaxin peptide at a more acute time point, THP-1 wild type and recombinant cells were assessed for migratory responses to relaxin under conditions that were more conducive for such activity. As previously established, monocytes migrate favorably on laminin-coated transwells (64). When THP-1 migratory response was assessed at 3 h on laminin-coated transwells, wild type cells exhibited responses to RLXH, MCP-1, and both treatments which were essentially identical to those observed at 24 h on uncoated transwells (i.e.…”

Downregulation of laminin α4 chain expression inhibits glioma invasionin vitro andin vivo

“…It has been reported that laminin-8 potently promotes cell migration compared to other isoforms of laminin and fibronectin in vitro. 18,19,32,33 However, in vitro studies alone could not assess glioma invasion because this process is extremely complex and intimately involves the ECM intrinsic to the brain and normal brain architecture. To overcome these problems, we established organotypic brain slice cultures that are analogous to the conditions of the normal brain in vivo.…”

An adhesion protein of Salmonella enterica serovar Typhi is required for pathogenesis and potential target for vaccine development

“…Alanine scanning mutation of the loop is currently under way in our laboratory to further characterize the binding residue(s). Laminin binding also explains T2544-mediated attachment to cell monolayers, as both IECs and THP-1 secrete laminin (25)(26)(27). However, we have not excluded binding of T2544 to the cell surface receptor (s).…”