Retinoic acid inhibits the infectivity and growth of Chlamydia pneumoniae in epithelial and endothelial cells through different receptors.
Chlamydia pneumoniae is a human respiratory pathogen that has also been associated with cardiovascular disease. C. pneumoniae infection accelerates atherosclerotic plaque development in hyperlipidemic animals and promotes oxidation of low density lipoprotein in vitro. All-trans-retinoic acid (ATRA), an antioxidant, has been shown to inhibit C. pneumoniae infectivity for endothelial cells by preventing binding of the organism to the M6P/IGF2 receptor on the cell surface. This current study investigates whether ATRA similarly affects C. pneumoniae infectivity of epithelial cells, which are the primary site of infection in the respiratory tract, and the effects on intracellular growth in both endothelial and epithelial cells. Because ATRA binds to both the nuclear retinoid acid receptor (RAR) and the M6P/IGF2 receptor, 4-[(E)-2-(5,6,7,8-tetrahydro-5,5,8,8-tetramethyl-2-naphthalenyl)-1-propenyl]benzoic acid (TTNPB), an ATRA analog, which binds to the RAR but not the M6P/IGF2 receptor was used to differentiate the receptor mediating the effects of ATRA. The results of this study showed two separate effects of ATRA. The first effect is through interaction with the M6P/IGF2 receptor on the cell surface preventing attachment of the organism (inhibition by ATRA but not TTNPB) in endothelial cells and the second is through the nuclear receptor (inhibition by both ATRA and TTNPB) which inhibits growth in both epithelial and endothelial cells.
Puolakkainen
Mirja
M
Department of Pathobiology, University of Washington, Box 357238, Seattle, WA 91895, USA.
Lee
Amy
A
Nosaka
Tadayoshi
T
Fukushi
Hideto
H
Kuo
Cho-Chou
CC
Campbell
Lee Ann
LA
D001422:Bacterial Adhesion / Q000187:drug effects; D002460:Cell Line; D016993:Chlamydophila pneumoniae / Q000254:growth & development / Q000276:immunology*; D003593:Cytoplasm / Q000382:microbiology / Q000648:ultrastructure; D042783:Endothelial Cells / Q000382:microbiology*; D006801:Humans; D002479:Inclusion Bodies / Q000382:microbiology / Q000648:ultrastructure; D017527:Receptor, IGF Type 2 / Q000037:antagonists & inhibitors*; D018168:Receptors, Retinoic Acid / Q000037:antagonists & inhibitors*; D014212:Tretinoin / Q000276:immunology*
D017527:Receptor, IGF Type 2; D018168:Receptors, Retinoic Acid; D014212:Tretinoin