Differential expression of rat frizzled-related frzb-1 and frizzled receptor fz1 and fz2 genes in the rat aorta after balloon injury.
Frzb-1 is a secreted protein, presenting similarity with the Wnt-binding domain of the frizzled family of receptors, which acts as an antagonist of Wnt signaling. Using mRNA differential display in the rat aorta balloon injury model, we identified overexpression of Frzb-1 mRNA and determined its cDNA sequence. By quantitative reverse transcription-polymerase chain reaction and RNase protection assay, a biphasic upregulation of rFrzb-1 expression was observed, with significant peaks of a 1.7-fold increase at 4 days and a 1. 5-fold increase at 3 weeks after aortic injury in vivo. In contrast, expression of the rat frizzled receptor genes rfz1 and rfz2 were transiently downregulated at 1 and 4 hours after balloon injury. rFrzb-1 was expressed predominantly in rat aortic smooth muscle cells (RASMCs) and barely in aortic fibroblasts and endothelial cells (RAECs), whereas rfz1 and rfz2 were expressed in all of these cells when stimulated with serum. Transient downregulation of rfz1 and rfz2 expression was reproduced by stimulation of quiescent RASMCs with serum, platelet-derived growth factor-BB, or fibroblast growth factor-2. In contrast, rFrzb-1 expression diminished slowly, to reach a 2-fold decrease 24 hours after growth factor stimulation, implying that quiescent RASMCs expressed higher levels of rFrzb-1 mRNA than did proliferative ones. Overexpression of rFrzb-1 in the aorta seemed to coincide with the arrest of RASMC proliferation occurring in the media 4 days and in the neointima 3 weeks after balloon injury. Our results demonstrate that rfrzb-1, rfz1, and rfz2 are differentially regulated in response to arterial injury and that this modulation seems to follow the proliferative state of RASMCs, suggesting that these Wnt-signaling components may be involved in intimal vascular disease.
Mao
C
C
INSERM U525, Hopital Saint-Louis, and INSERM U460, Faculté Bichat, Paris, France.
Malek
O T
OT
Pueyo
M E
ME
Steg
P G
PG
Soubrier
F
F
D000818:Animals; D001011:Aorta / Q000293:injuries* / Q000378:metabolism* / Q000473:pathology; D001483:Base Sequence; D000077214:Becaplermin; D002404:Catheterization / Q000009:adverse effects; D002455:Cell Division; D017931:DNA Primers / Q000235:genetics; D016222:Fibroblast Growth Factor 2 / Q000494:pharmacology; D051157:Frizzled Receptors; D015870:Gene Expression / Q000187:drug effects; D006023:Glycoproteins; D047908:Intracellular Signaling Peptides and Proteins; D008969:Molecular Sequence Data; D009131:Muscle, Smooth, Vascular / Q000293:injuries / Q000378:metabolism / Q000473:pathology; D010982:Platelet-Derived Growth Factor / Q000494:pharmacology; D011506:Proteins / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000378:metabolism; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D011921:Rats, Inbred WKY; D043562:Receptors, G-Protein-Coupled; D017981:Receptors, Neurotransmitter / Q000235:genetics*; D015398:Signal Transduction; D051153:Wnt Proteins; D029961:Zebrafish Proteins; D000099274:Frizzled-Related Proteins
D000077214:Becaplermin; D017931:DNA Primers; D016222:Fibroblast Growth Factor 2; D051157:Frizzled Receptors; D006023:Glycoproteins; D047908:Intracellular Signaling Peptides and Proteins; D010982:Platelet-Derived Growth Factor; D011506:Proteins; D011518:Proto-Oncogene Proteins; D020574:Proto-Oncogene Proteins c-sis; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; D017981:Receptors, Neurotransmitter; D051153:Wnt Proteins; D029961:Zebrafish Proteins; D000099274:Frizzled-Related Proteins; C078603:Fzd1 protein, rat; C078604:Fzd2 protein, rat