Sonic Hedgehog induces Notch target gene expression in vascular smooth muscle cells via VEGF-A.
OBJECTIVE
Notch, VEGF, and components of the Hedgehog (Hh) signaling pathway have been implicated in vascular morphogenesis. The role of Notch in mediating hedgehog control of adult vascular smooth muscle cell (SMC) growth and survival remains unexplored.


RESULTS
In cultured SMCs, activation of Hh signaling with recombinant rShh (3.5 mug/mL) or plasmid encoded Shh increased Ptc1 expression, enhanced SMC growth and survival and promoted Hairy-related transcription factor (Hrt) expression while concomitantly increasing VEGF-A levels. These effects were significantly reversed after Hh inhibition with cyclopamine. Shh-induced stimulation of Hrt-3 mRNA and SMC growth and survival was attenuated after inhibition of Notch-mediated CBF-1/RBP-Jk-dependent signaling with RPMS-1 while siRNA knockdown of Hrt-3 inhibited SMC growth and survival. Recombinant VEGF-A increased Hrt-3 mRNA levels while siRNA knockdown abolished rShh stimulated VEGF-A expression while concomitantly inhibiting Shh-induced increases in Hrt-3 mRNA levels, proliferating cell nuclear antigen (PCNA), and Notch 1 IC expression, respectively. Hedgehog components were expressed within intimal SMCs of murine carotid arteries after vascular injury concomitant with a significant increase in mRNA for Ptc1, Gli(2), VEGF-A, Notch 1, and Hrts.


CONCLUSIONS
Hedgehog promotes a coordinate regulation of Notch target genes in adult SMCs via VEGF-A.
Morrow
David
D
Department of Surgery, University of Rochester Medical Center, NY, USA.
Cullen
John P
JP
Liu
Weimin
W
Guha
Shaunta
S
Sweeney
Catherine
C
Birney
Yvonne A
YA
Collins
Nora
N
Walls
Dermot
D
Redmond
Eileen M
EM
Cahill
Paul A
PA
D000818:Animals; D002339:Carotid Arteries / Q000166:cytology / Q000378:metabolism*; D002460:Cell Line; D005786:Gene Expression Regulation; D053823:Hedgehog Proteins / Q000502:physiology*; D006801:Humans; D051379:Mice; D009131:Muscle, Smooth, Vascular / Q000378:metabolism; D032389:Myocytes, Smooth Muscle / Q000378:metabolism*; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D051881:Receptor, Notch1 / Q000502:physiology*; D042461:Vascular Endothelial Growth Factor A / Q000235:genetics / Q000378:metabolism*
D053823:Hedgehog Proteins; D012333:RNA, Messenger; D051881:Receptor, Notch1; C509239:SHH protein, human; C465570:Shh protein, mouse; D042461:Vascular Endothelial Growth Factor A