Jagged1-selective notch signaling induces smooth muscle differentiation via a RBP-Jkappa-dependent pathway.
The Notch signaling pathway plays a crucial role in specifying cellular fates by interaction between cellular neighbors; however, the molecular mechanism underlying smooth muscle cell (SMC) differentiation by Notch signaling has not been well characterized. Here we demonstrate that Jagged1-Notch signaling promotes SMC differentiation from mesenchymal cells. Overexpression of the Notch intracellular domain, an activated form of Notch, up-regulates the expression of multiple SMC marker genes including SMC-myosin heavy chain (Sm-mhc) in mesenchymal 10T1/2 cells, but not in non-mesenchymal cells. Physiological Notch stimulation by its ligand Jagged1, but not Dll4, directly induces Sm-mhc expression in 10T1/2 cells without de novo protein synthesis, indicative of a ligand-selective effect. Jagged1-induced expression of SM-MHC was blocked bygamma-secretase inhibitor, N-(N-(3,5-difluorophenyl)-l-alanyl)-S-phenylglycine t-butyl ester, which impedes Notch signaling. Using Rbp-jkappa-deficient cells and site-specific mutagenesis of the SM-MHC gene, we show that such an induction is independent of the myocardin-serum response factor-CArG complex, but absolutely dependent on RBP-Jkappa, a major mediator of Notch signaling, and its cognate binding sequence. Of importance, Notch signaling and myocardin synergistically activate SM-MHC gene expression. Taken together, these data suggest that the Jagged1-Notch pathway constitutes an instructive signal for SMC differentiation through an RBP-Jkappa-dependent mechanism and augments gene expression mediated by the myocardin-SRF-CArG complex. Given that Notch pathway components are expressed in vascular SMC during normal development and disease, Notch signaling is likely to play a pivotal role in such situations to modulate the vascular smooth muscle cell phenotype.
Doi
Hiroshi
H
Department of Medicine and Biological Science, Education and Research Center, Laboratory Science, Gunma University Graduate School of Medicine, 3-39-15 Showa-machi, Maebashi, Gunma, Japan.
Iso
Tatsuya
T
Sato
Hiroko
H
Yamazaki
Miki
M
Matsui
Hiroki
H
Tanaka
Toru
T
Manabe
Ichiro
I
Arai
Masashi
M
Nagai
Ryozo
R
Kurabayashi
Masahiko
M
D000256:Adenoviridae / Q000378:metabolism; D000818:Animals; D002135:Calcium-Binding Proteins / Q000378:metabolism / Q000502:physiology*; D002454:Cell Differentiation; D002460:Cell Line; D017930:Genes, Reporter; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein / Q000378:metabolism*; D036341:Intercellular Signaling Peptides and Proteins / Q000378:metabolism / Q000502:physiology*; D000072100:Jagged-1 Protein; D008321:Mammary Glands, Animal; D008565:Membrane Proteins / Q000378:metabolism / Q000502:physiology*; D051379:Mice; D009130:Muscle, Smooth / Q000166:cytology*; D010957:Plasmids / Q000378:metabolism; D051880:Receptors, Notch / Q000378:metabolism*; D000072099:Serrate-Jagged Proteins; D015398:Signal Transduction
D002135:Calcium-Binding Proteins; D051819:Immunoglobulin J Recombination Signal Sequence-Binding Protein; D036341:Intercellular Signaling Peptides and Proteins; C000606274:Jag1 protein, mouse; D000072100:Jagged-1 Protein; D008565:Membrane Proteins; D051880:Receptors, Notch; D000072099:Serrate-Jagged Proteins