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J Biol Chem. 2016 Jan 22;291(4):1538-51. doi: 10.1074/jbc.M115.685453. Epub 2015 Dec 1.

Hajdu Cheney Mouse Mutants Exhibit Osteopenia, Increased Osteoclastogenesis, and Bone Resorption.

Author information

1
From the Departments of Orthopaedic Surgery, Medicine, canalis@uchc.edu.
2
From the Departments of Orthopaedic Surgery.
3
Cell Biology, Genetics, and Genome Sciences Biology.
4
Medicine, Center on Aging, University of Connecticut Health Center, Farmington, Connecticut 06030.
5
From the Departments of Orthopaedic Surgery, Medicine.

Abstract

Notch receptors are determinants of cell fate and function and play a central role in skeletal development and bone remodeling. Hajdu Cheney syndrome, a disease characterized by osteoporosis and fractures, is associated with NOTCH2 mutations resulting in a truncated stable protein and gain-of-function. We created a mouse model reproducing the Hajdu Cheney syndrome by introducing a 6955C→T mutation in the Notch2 locus leading to a Q2319X change at the amino acid level. Notch2(Q2319X) heterozygous mutants were smaller and had shorter femurs than controls; and at 1 month of age they exhibited cancellous and cortical bone osteopenia. As the mice matured, cancellous bone volume was restored partially in male but not female mice, whereas cortical osteopenia persisted in both sexes. Cancellous bone histomorphometry revealed an increased number of osteoclasts and bone resorption, without a decrease in osteoblast number or bone formation. Osteoblast differentiation and function were not affected in Notch2(Q2319X) cells. The pre-osteoclast cell pool, osteoclast differentiation, and bone resorption in response to receptor activator of nuclear factor κB ligand in vitro were increased in Notch2(Q2319X) mutants. These effects were suppressed by the γ-secretase inhibitor LY450139. In conclusion, Notch2(Q2319X) mice exhibit cancellous and cortical bone osteopenia, enhanced osteoclastogenesis, and increased bone resorption.

KEYWORDS:

Hajdu Cheney syndrome; Notch pathway; Notch protein; animal model; bone; osteoblast; osteoclast

PMID:
26627824
PMCID:
PMC4722436
DOI:
10.1074/jbc.M115.685453
[Indexed for MEDLINE]
Free PMC Article

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