The ubiquitin ligase Nedd4-1 is required for heart development and is a suppressor of thrombospondin-1.
Nedd4 (Nedd4-1) is a Hect domain E3 ubiquitin ligase that also contains a C2 domain and three WW domains. Despite numerous in vitro studies, its biological function in vivo is not well understood. Here we show that disruption of Nedd4-1 in mice (leaving Nedd4-2 intact) caused embryonic lethality at mid gestation, with pronounced heart defects (double-outlet right ventricle and atrioventricular cushion defects) and vasculature abnormalities. Quantitative mass spectrometry and immunoblot analyses of lysates from the wild type and knock-out mouse embryonic fibroblasts to identify Nedd4-1 in vivo targets revealed dramatically increased amounts of thrombospondin-1 (Tsp-1) in the knock-out mouse embryonic fibroblasts and embryos. Tsp-1 is an inhibitor of angiogenesis, and its elevated level was mediated primarily by enhanced transcription. Interestingly, the administration of aspirin (an inhibitor of Tsp-1) to the pregnant heterozygote mothers led to a reduction in Tsp-1 levels and a substantial rescue of the embryonic lethality. These results suggest that Nedd4-1 is a suppressor of Tsp1 and that increased levels of Tsp-1 in the Nedd4-1 knock-out mice may have contributed to the developmental defect observed in the embryos.
Fouladkou
Fatemeh
F
Program in Cell Biology and the Mouse Imaging Centre, The Hospital for Sick Children, Toronto, Ontario M5G 1L7, Canada.
Lu
Chen
C
Jiang
Chong
C
Zhou
Limei
L
She
Yimin
Y
Walls
Jonathon R
JR
Kawabe
Hiroshi
H
Brose
Nils
N
Henkelman
R M
RM
Huang
Annie
A
Bruneau
Benoit G
BG
Rotin
Daniela
D
D000818:Animals; D001241:Aspirin / Q000494:pharmacology; D056827:Endosomal Sorting Complexes Required for Transport / Q000172:deficiency / Q000502:physiology*; D005260:Female; D005347:Fibroblasts; D006321:Heart / Q000196:embryology / Q000254:growth & development*; D006330:Heart Defects, Congenital / Q000235:genetics; D051379:Mice; D018345:Mice, Knockout; D000075702:Nedd4 Ubiquitin Protein Ligases; D011247:Pregnancy; D019700:Thrombospondin 1 / Q000037:antagonists & inhibitors* / Q000187:drug effects / Q000235:genetics; D014158:Transcription, Genetic; D044767:Ubiquitin-Protein Ligases / Q000172:deficiency / Q000502:physiology*
D056827:Endosomal Sorting Complexes Required for Transport; D019700:Thrombospondin 1; D000075702:Nedd4 Ubiquitin Protein Ligases; C000618461:Nedd4l protein, mouse; D044767:Ubiquitin-Protein Ligases; D001241:Aspirin