• Register
X
Forgot Password

If you have forgotten your password you can enter your email here and get a temporary password sent to your email.

X

Leaving Community

Are you sure you want to leave this community? Leaving the community will revoke any permissions you have been granted in this community.

No
Yes

MEK-ERK pathway modulation ameliorates disease phenotypes in a mouse model of Noonan syndrome associated with the Raf1(L613V) mutation.

Hypertrophic cardiomyopathy (HCM) is a leading cause of sudden death in children and young adults. Abnormalities in several signaling pathways are implicated in the pathogenesis of HCM, but the role of the RAS-RAF-MEK-ERK MAPK pathway has been controversial. Noonan syndrome (NS) is one of several autosomal-dominant conditions known as RASopathies, which are caused by mutations in different components of this pathway. Germline mutations in RAF1 (which encodes the serine-threonine kinase RAF1) account for approximately 3%-5% of cases of NS. Unlike other NS alleles, RAF1 mutations that confer increased kinase activity are highly associated with HCM. To explore the pathogenesis of such mutations, we generated knockin mice expressing the NS-associated Raf1(L613V) mutation. Like NS patients, mice heterozygous for this mutation (referred to herein as L613V/+ mice) had short stature, craniofacial dysmorphia, and hematologic abnormalities. Valvuloseptal development was normal, but L613V/+ mice exhibited eccentric cardiac hypertrophy and aberrant cardiac fetal gene expression, and decompensated following pressure overload. Agonist-evoked MEK-ERK activation was enhanced in multiple cell types, and postnatal MEK inhibition normalized the growth, facial, and cardiac defects in L613V/+ mice. These data show that different NS genes have intrinsically distinct pathological effects, demonstrate that enhanced MEK-ERK activity is critical for causing HCM and other RAF1-mutant NS phenotypes, and suggest a mutation-specific approach to the treatment of RASopathies.

Pubmed ID: 21339642

Authors

  • Wu X
  • Simpson J
  • Hong JH
  • Kim KH
  • Thavarajah NK
  • Backx PH
  • Neel BG
  • Araki T

Journal

The Journal of clinical investigation

Publication Data

March 2, 2011

Associated Grants

  • Agency: Canadian Institutes of Health Research, Id: 106526
  • Agency: Canadian Institutes of Health Research, Id: 153103
  • Agency: NHLBI NIH HHS, Id: HL083273
  • Agency: NCI NIH HHS, Id: R37 CA049152
  • Agency: NCI NIH HHS, Id: R37CA49152

Mesh Terms

  • Alleles
  • Animals
  • Cardiomyopathy, Hypertrophic
  • Disease Models, Animal
  • Extracellular Signal-Regulated MAP Kinases
  • Female
  • Germ-Line Mutation
  • Heterozygote
  • Male
  • Mice
  • Mice, Transgenic
  • Mitogen-Activated Protein Kinase Kinases
  • Mutation
  • Noonan Syndrome
  • Proto-Oncogene Proteins c-raf