Notch signaling regulates endothelial progenitor cell activity during recovery from arterial injury in hypercholesterolemic mice.
BACKGROUND
Little is known about the role of endothelial progenitor cells (EPCs) in atherosclerosis. Accordingly, we performed a series of assessments with hypercholesterolemic (apolipoprotein E-null [ApoE(-/-)]) and wild-type (WT) mice to evaluate how cholesterol influences reendothelialization, atherosclerosis, and EPC function after arterial injury.


RESULTS
Unexpectedly, reendothelialization (assessed by resistance to Evans blue staining) and circulating EPC counts (EPC culture assay) were greater in ApoE(-/-) mice than in WT mice, and transplantation of ApoE(-/-) bone marrow in WT mice accelerated endothelial recovery and increased recruitment of bone marrow-derived EPCs to the neoendothelium. Cholesterol concentration-dependently promoted the proliferation (MTS assay) of both ApoE(-/-) and WT EPCs, and the concentration dependence of EPC adhesion (to vitronectin-, collagen type I-, fibronectin-, and laminin-coated plates), migration (modified Boyden chamber assay), and antiapoptotic (terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling stain) activity was biphasic. Cholesterol enhanced the messenger RNA expression (quantitative, real-time reverse-transcription polymerase chain reaction) of vascular endothelial growth factor and inhibited Notch1 messenger RNA expression in both ApoE(-/-) and WT EPCs, whereas endothelial nitric oxide synthase messenger RNA expression increased in ApoE(-/-) EPCs and declined in WT EPCs after cholesterol exposure. EPC activity was greater in Notch1(+/-) EPCs than in WT EPCs, and transplantation of Notch1(+/-) bone marrow accelerated endothelial recovery after arterial injury in WT mice.


CONCLUSIONS
The results presented here provide novel insights into the role of EPCs during atherosclerosis and suggest that cholesterol and Notch1 may be involved in the regulation of EPC activity.
Ii
Masaaki
M
Feinberg Cardiovascular Research Institute, Northwestern University, Chicago, IL 60611, USA.
Takeshita
Kyosuke
K
Ibusuki
Kayoko
K
Luedemann
Corinne
C
Wecker
Andrea
A
Eaton
Elizabeth
E
Thorne
Tina
T
Asahara
Takayuki
T
Liao
James K
JK
Losordo
Douglas W
DW
D000818:Animals; D001057:Apolipoproteins E / Q000172:deficiency / Q000235:genetics; D050197:Atherosclerosis / Q000209:etiology / Q000235:genetics / Q000473:pathology; D016026:Bone Marrow Transplantation; D020212:Carotid Artery Injuries / Q000150:complications / Q000473:pathology*; D002465:Cell Movement; D002784:Cholesterol / Q000097:blood; D042783:Endothelial Cells / Q000473:pathology*; D005786:Gene Expression Regulation; D005838:Genotype; D006937:Hypercholesterolemia / Q000150:complications / Q000235:genetics / Q000473:pathology*; D008297:Male; D059630:Mesenchymal Stem Cells / Q000473:pathology*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D052250:Nitric Oxide Synthase Type III / Q000096:biosynthesis / Q000235:genetics; D012333:RNA, Messenger / Q000096:biosynthesis; D011828:Radiation Chimera; D051881:Receptor, Notch1 / Q000096:biosynthesis / Q000172:deficiency / Q000235:genetics / Q000502:physiology*; D015398:Signal Transduction; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000235:genetics
D001057:Apolipoproteins E; C497762:Notch1 protein, mouse; D012333:RNA, Messenger; D051881:Receptor, Notch1; D042461:Vascular Endothelial Growth Factor A; C467480:vascular endothelial growth factor A, mouse; D002784:Cholesterol; D052250:Nitric Oxide Synthase Type III; C496315:Nos3 protein, mouse