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Updated: Dec 29, 2025
Stimulation of Notch Signaling in Mouse Osteoclast Precursors
Published on: February 28, 2017
Antisense oligonucleotides targeting Notch2 ameliorate the osteopenic phenotype in a mouse model of Hajdu-Cheney
Ernesto Canalis1,2,3, Tamar R Grossman4, Michele Carrer4
1Department of Orthopaedic Surgery, UConn Health, Farmington, Connecticut 06030 canalis@uchc.edu.
Abstract:
Notch receptors play critical roles in cell-fate decisions and in the regulation of skeletal development and bone remodeling. Gain-of-function NOTCH2 mutations can cause Hajdu-Cheney syndrome, an untreatable disease characterized by osteoporosis and fractures, craniofacial developmental abnormalities, and acro-osteolysis. We have previously created a mouse model harboring a point 6955C→T mutation in the Notch2 locus upstream of the PEST domain, and we termed this model Notch2 Heterozygous Notch2 mutant mice exhibit severe cancellous and cortical bone osteopenia due to increased bone resorption. In this work, we demonstrate that the subcutaneous administration of Notch2 antisense oligonucleotides (ASO) down-regulates Notch2 and the Notch target genes Hes-related family basic helix-loop-helix transcription factor with YRPW motif 1 (Hey1), Hey2, and HeyL in skeletal tissue from Notch2 mice. Results of microcomputed tomography experiments indicated that the administration of Notch2 ASOs ameliorates the cancellous osteopenia of Notch2 mice, and bone histomorphometry analysis revealed decreased osteoclast numbers in Notch2 ASO-treated Notch2 mice. Notch2 ASOs decreased the induction of mRNA levels of TNF superfamily member 11 (Tnfsf11, encoding the osteoclastogenic protein RANKL) in cultured osteoblasts and osteocytes from Notch2 mice. Bone marrow-derived macrophage cultures from the Notch2 mice displayed enhanced osteoclastogenesis, which was suppressed by Notch2 ASOs. In conclusion, Notch2 mice exhibit cancellous bone osteopenia that can be ameliorated by systemic administration of Notch2 ASOs.
Insights
Notch2 mutations cause bone loss in mice. Treating these mice with Notch2 antisense oligonucleotides (ASOs) reduced bone resorption and improved bone density, offering a potential therapeutic strategy for related bone diseases.
Area of Science:
- Skeletal Biology
- Genetics
- Pharmacology
Background:
- Notch receptors are crucial for skeletal development and bone remodeling.
- Gain-of-function NOTCH2 mutations lead to Hajdu-Cheney syndrome, characterized by severe bone loss and developmental defects.
- A mouse model with a Notch2 mutation (Notch2) exhibits significant bone osteopenia due to increased bone resorption.
Purpose of the Study:
- To investigate the therapeutic potential of Notch2 antisense oligonucleotides (ASOs) in ameliorating bone loss in a mouse model of NOTCH2 mutation.
- To assess the effect of Notch2 ASOs on Notch signaling pathway components and osteoclastogenesis.
Main Methods:
- Subcutaneous administration of Notch2 ASOs to Notch2 mutant mice.
- Analysis of Notch2 and target gene (Hey1, Hey2, HeyL) expression in skeletal tissues.
- Microcomputed tomography (micro-CT) and bone histomorphometry to evaluate bone structure and osteoclast numbers.
- Assessment of osteoclastogenesis in bone marrow-derived macrophages and RANKL expression in osteoblasts/osteocytes.
Main Results:
- Notch2 ASO treatment successfully downregulated Notch2 and its target genes Hey1, Hey2, and HeyL in skeletal tissues.
- Micro-CT and histomorphometry revealed amelioration of cancellous osteopenia and a decrease in osteoclast numbers in treated mice.
- Notch2 ASOs reduced RANKL mRNA levels and suppressed enhanced osteoclastogenesis in bone marrow-derived macrophages from Notch2 mice.
Conclusions:
- Systemic administration of Notch2 ASOs effectively ameliorates cancellous bone osteopenia in a mouse model with Notch2 mutation.
- The therapeutic effect is mediated by downregulating Notch2 signaling, reducing osteoclast activity, and decreasing RANKL expression.
- Notch2 ASOs represent a promising therapeutic strategy for Hajdu-Cheney syndrome and other bone disorders associated with NOTCH2 dysfunction.
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