Microfibrils and fibrillin-1 induce integrin-mediated signaling, proliferation and migration in human endothelial cells.
Microfibrils are macromolecular complexes associated with elastin to form elastic fibers that endow extensible tissues, such as arteries, lungs, and skin, with elasticity property. Fibrillin-1, the main component of microfibrils, is a 350-kDa glycoprotein for which genetic haploinsufficiency in humans can lead to Marfan syndrome, a severe polyfeatured pathology including aortic aneurysms and dissections. Microfibrils and fibrillin-1 fragments mediate adhesion of several cell types, including endothelial cells, while fibrillin-1 additionally triggers lung and mesangial cell migration. However, fibrillin-1-induced intracellular signaling is unknown. We have studied the signaling events induced in human umbilical venous endothelial cells (HUVECs) by aortic microfibrils as well as recombinant fibrillin-1 Arg-Gly-Asp (RGD)-containing fragments PF9 and PF14. Aortic microfibrils and PF14, not PF9, substantially and dose dependently increased HUVEC cytoplasmic and nuclear calcium levels measured using the fluorescent dye Fluo-3. This effect of PF14 was confirmed in bovine aortic endothelial cells. PF14 action in HUVECs was mediated by αvβ3 and α5β1 integrins, phospholipase-C, inosital 1,4,5-trisphosphate, and mobilization of intracellular calcium stores, whereas membrane calcium channels were not or only slightly implicated, as shown in patch-clamp experiments. Finally, PF14 enhanced endothelial cell proliferation and migration. Hence, fibrillin-1 sequences may physiologically activate endothelial cells. Genetic fibrillin-1 deficiency could alter normal endothelial signaling and, since endothelium dysfunction is an important contributor to Marfan syndrome, participate in the arterial anomalies associated with this developmental disease.
Mariko
Boubacar
B
Laboratoire Physiopathologies Vasculaires, Interactions Cellulaires, Signalisation et Vieillissement, Université Joseph Fourier, CEA, Institut National de Santé et de Recherche Médicale, U882, Grenoble, France.
Ghandour
Zeinab
Z
Raveaud
Stéphanie
S
Quentin
Mickaël
M
Usson
Yves
Y
Verdetti
Jean
J
Huber
Philippe
P
Kielty
Cay
C
Faury
Gilles
G
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002417:Cattle; D002448:Cell Adhesion / Q000502:physiology; D002465:Cell Movement / Q000502:physiology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D042783:Endothelial Cells / Q000166:cytology / Q000502:physiology*; D000071838:Fibrillin-1; D000071837:Fibrillins; D006801:Humans; D039482:Integrin alpha5 / Q000235:genetics / Q000378:metabolism*; D039564:Integrin alphaV / Q000235:genetics / Q000378:metabolism*; D008382:Marfan Syndrome / Q000235:genetics / Q000378:metabolism / Q000473:pathology; D020894:Microfibrils / Q000378:metabolism*; D008840:Microfilament Proteins / Q000235:genetics / Q000378:metabolism*; D018408:Patch-Clamp Techniques; D015398:Signal Transduction / Q000502:physiology*; D054392:Adipokines
D002118:Calcium; D000071838:Fibrillin-1; D000071837:Fibrillins; D039482:Integrin alpha5; D039564:Integrin alphaV; D008840:Microfilament Proteins; C000605722:FBN1 protein, human; D054392:Adipokines