PLoS ONE (Jan 2014)

Absence of cardiovascular manifestations in a haploinsufficient Tgfbr1 mouse model.

  • Marjolijn Renard,
  • Bram Trachet,
  • Christophe Casteleyn,
  • Laurence Campens,
  • Pieter Cornillie,
  • Bert Callewaert,
  • Steven Deleye,
  • Bert Vandeghinste,
  • Paula M van Heijningen,
  • Harry Dietz,
  • Filip De Vos,
  • Jeroen Essers,
  • Steven Staelens,
  • Patrick Segers,
  • Bart Loeys,
  • Paul Coucke,
  • Anne De Paepe,
  • Julie De Backer

DOI
https://doi.org/10.1371/journal.pone.0089749
Journal volume & issue
Vol. 9, no. 2
p. e89749

Abstract

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Loeys-Dietz syndrome (LDS) is an autosomal dominant arterial aneurysm disease belonging to the spectrum of transforming growth factor β (TGFβ)-associated vasculopathies. In its most typical form it is characterized by the presence of hypertelorism, bifid uvula/cleft palate and aortic aneurysm and/or arterial tortuosity. LDS is caused by heterozygous loss of function mutations in the genes encoding TGFβ receptor 1 and 2 (TGFBR1 and -2), which lead to a paradoxical increase in TGFβ signaling. To address this apparent paradox and to gain more insight into the pathophysiology of aneurysmal disease, we characterized a new Tgfbr1 mouse model carrying a p.Y378* nonsense mutation. Study of the natural history in this model showed that homozygous mutant mice die during embryonic development due to defective vascularization. Heterozygous mutant mice aged 6 and 12 months were morphologically and (immuno)histochemically indistinguishable from wild-type mice. We show that the mutant allele is degraded by nonsense mediated mRNA decay, expected to result in haploinsufficiency of the mutant allele. Since this haploinsufficiency model does not result in cardiovascular malformations, it does not allow further study of the process of aneurysm formation. In addition to providing a comprehensive method for cardiovascular phenotyping in mice, the results of this study confirm that haploinsuffciency is not the underlying genetic mechanism in human LDS.