Lipoprotein receptor-related protein 1 regulates collagen 1 expression, proteolysis, and migration in human pleural mesothelial cells.
The low-density lipoprotein receptor-related protein 1 (LRP-1) binds and can internalize a diverse group of ligands, including members of the fibrinolytic pathway, urokinase plasminogen activator (uPA), and its receptor, uPAR. In this study, we characterized the role of LRP-1 in uPAR processing, collagen synthesis, proteolysis, and migration in pleural mesothelial cells (PMCs). When PMCs were treated with the proinflammatory cytokines TNF-α and IL-1β, LRP-1 significantly decreased at the mRNA and protein levels (70 and 90%, respectively; P < 0.05). Consequently, uPA-mediated uPAR internalization was reduced by 80% in the presence of TNF-α or IL-1β (P < 0.05). In parallel studies, LRP-1 neutralization with receptor-associated protein (RAP) significantly reduced uPA-dependent uPAR internalization and increased uPAR stability in PMCs. LRP-1-deficient cells demonstrated increased uPAR t(1/2) versus LRP-1-expressing PMCs. uPA enzymatic activity was also increased in LRP-1-deficient and neutralized cells, and RAP potentiated uPA-dependent migration in PMCs. Collagen expression in PMCs was also induced by uPA, and the effect was potentiated in RAP-treated cells. These studies indicate that TNF-α and IL-1β regulate LRP-1 in PMCs and that LRP-1 thereby contributes to a range of pathophysiologically relevant responses of these cells.
The Texas Lung Injury Institute, The University of Texas Health Science Center at Tyler, 11937 US Highway 271, Biomedical Research Building, Lab C-5, Tyler, TX 75708, USA. torry.tucker@uthct.edu
Torry A
TA
Tucker
LaTerrica
L
Williams
Kathleen
K
Koenig
Hema
H
Kothari
Andrey A
AA
Komissarov
Galina
G
Florova
Andrew P
AP
Mazar
Timothy C
TC
Allen
Khalil
K
Bdeir
L Vijaya
LV
Mohan Rao
Steven
S
Idell
D002460:Cell Line; D024042:Collagen Type I / Q000378:metabolism*; D004848:Epithelium / Q000378:metabolism*; D006801:Humans; D010994:Pleura / Q000166:cytology / Q000378:metabolism*; D059748:Proteolysis; D018110:Receptors, Lipoprotein / Q000378:metabolism*
D024042:Collagen Type I; D018110:Receptors, Lipoprotein