MEKK2 mediates aberrant ERK activation in neurofibromatosis type I

Area of Science:

• Molecular biology
• Skeletal biology
• Genetics

Background:

• Neurofibromatosis type I (NF1) is a genetic disorder with significant skeletal complications.
• Current treatments targeting the ERK pathway (MEK1/2 inhibitors) show promise but have dose-limiting toxicities due to broad pathway inhibition.
• Aberrant ERK activation downstream of NF1 loss contributes to NF1 skeletal pathology.

Purpose of the Study:

• To identify novel therapeutic targets for NF1 skeletal manifestations.
• To investigate the role of MEKK2 in the noncanonical ERK pathway in osteoblasts following NF1 loss.
• To evaluate MEKK2 inhibition as a potential therapeutic strategy for NF1.

Main Methods:

• Utilized mouse models with conditional deletion of Nf1 in osteoblasts (Nf1^fl/fl;Dmp1-Cre).
• Generated and analyzed mice lacking MEKK2 (Mekk2^-/-).
• Assessed skeletal phenotypes in compound mutant mice (Nf1^fl/fl;Mekk2^-/-;Dmp1-Cre) and evaluated FDA-approved MEKK2 inhibitors.

Main Results:

• MEKK2 was identified as a novel component of a noncanonical ERK pathway in osteoblasts mediating aberrant ERK activation in NF1.
• Mice with conditional deletion of Nf1 and Mekk2 deletion showed amelioration of NF1-associated skeletal phenotypes.
• FDA-approved MEKK2 inhibitors demonstrated efficacy in ameliorating NF1 skeletal pathology in preclinical models.

Conclusions:

• MEKK2 acts as a MAP3K in the osteoblast ERK pathway, playing a critical role in NF1 skeletal pathogenesis.
• Targeting MEKK2 offers a more specific therapeutic strategy for NF1 skeletal disease compared to broad MEK1/2 inhibition.
• MEKK2 inhibition represents a promising new avenue for treating the skeletal manifestations of Neurofibromatosis type I.