Mouse cytomegalovirus M33 is necessary and sufficient in virus-induced vascular smooth muscle cell migration.
Mouse cytomegalovirus (MCMV) encodes two potential seven-transmembrane-spanning proteins with homologies to cellular chemokine receptors, M33 and M78. While these virus-encoded chemokine receptors are necessary for the in vivo pathogenesis of MCMV, the function of these proteins is unknown. Since vascular smooth muscle cell (SMC) migration is of critical importance for the development of atherosclerosis and other vascular diseases, the ability of M33 to promote SMC motility was assessed. Similar to human CMV, MCMV induced the migration of mouse aortic SMCs but not mouse fibroblasts. To demonstrate whether M33 was required for MCMV-induced SMC migration, we employed interfering-RNA technology to specifically knock down M33 expression in the context of viral infection. The knockdown of M33 resulted in the specific reduction of M33 protein expression and ablation of MCMV-mediated SMC migration but failed to reduce viral growth in cultured cells. Adenovirus vector expression of M33 was sufficient to promote SMC migration, which was enhanced in the presence of recombinant mouse RANTES (mRANTES). In addition, M33 promoted the activation of Rac1 and extracellular signal-related kinase 1/2 upon stimulation with mRANTES. These findings demonstrate that mRANTES is a ligand for this chemokine receptor and that the activation of M33 occurs in a ligand-dependent manner. Thus, M33 is a functional homologue of US28 that is required for MCMV-induced vascular SMC migration.
Melnychuk
Ryan M
RM
Department of Molecular Microbiology and Immunology, Oregon Health Sciences University, Portland, OR 97239, USA.
Smith
Patsy
P
Kreklywich
Craig N
CN
Ruchti
Franziska
F
Vomaske
Jennifer
J
Hall
Laurel
L
Loh
Lambert
L
Nelson
Jay A
JA
Orloff
Susan L
SL
Streblow
Daniel N
DN
D000818:Animals; D002465:Cell Movement; D018946:Chemokine CCL5 / Q000378:metabolism*; D051379:Mice; D019950:Mitogen-Activated Protein Kinase 1 / Q000378:metabolism; D048052:Mitogen-Activated Protein Kinase 3 / Q000378:metabolism; D018146:Muromegalovirus / Q000502:physiology*; D009131:Muscle, Smooth, Vascular / Q000166:cytology*; D041681:NIH 3T3 Cells; D009479:Neuropeptides / Q000378:metabolism; D034741:RNA, Small Interfering / Q000494:pharmacology; D019707:Receptors, Chemokine / Q000502:physiology*; D014764:Viral Proteins / Q000502:physiology*; D020744:rac GTP-Binding Proteins / Q000378:metabolism; D020830:rac1 GTP-Binding Protein
D018946:Chemokine CCL5; D009479:Neuropeptides; D034741:RNA, Small Interfering; C484602:Rac1 protein, mouse; D019707:Receptors, Chemokine; D014764:Viral Proteins; D019950:Mitogen-Activated Protein Kinase 1; D048052:Mitogen-Activated Protein Kinase 3; D020744:rac GTP-Binding Proteins; D020830:rac1 GTP-Binding Protein