Related Experiment Video

Updated: Jun 4, 2026

A RANKL-based Osteoclast Culture Assay of Mouse Bone Marrow to Investigate the Role of mTORC1 in Osteoclast Formation
09:37

A RANKL-based Osteoclast Culture Assay of Mouse Bone Marrow to Investigate the Role of mTORC1 in Osteoclast Formation

Published on: March 15, 2018

A Rras2-BMPR2 feedback loop sustains osteogenesis and represents a therapeutic target for osteoporosis

Renlei Yang1, Mingying Li2,3, Qi Xue4

  • 1Department of Plastic Surgery, Affiliated Friendship Plastic Surgery Hospital of Nanjing Medical University, Nanjing Medical University, Nanjing, China. yang_renlei@126.com.

Nature Communications
|June 2, 2026
PubMed

Insights

Ras-related protein 2 (Rras2) mutations cause Noonan syndrome. Rras2 deficiency in mice leads to osteopenia, but restoring Rras2 rescues bone loss, identifying a key pathway for bone health.

Area of Science:

  • Molecular biology
  • Genetics
  • Bone biology

Background:

  • Ras-related protein 2 (Rras2) mutations are associated with Noonan syndrome, a genetic disorder.
  • The precise function of Rras2 in maintaining bone homeostasis is not well understood.
  • Existing knowledge gaps hinder the development of targeted clinical interventions for bone-related disorders.

Purpose of the Study:

  • To elucidate the role of Rras2 in bone homeostasis and osteogenesis.
  • To investigate the molecular mechanisms by which Rras2 influences bone health.
  • To explore the therapeutic potential of Rras2 restoration in bone loss conditions.

Main Methods:

  • Utilized a mouse model deficient in Rras2 to study bone phenotypes.
  • Assessed osteogenic differentiation of bone marrow mesenchymal stem cells.
  • Investigated the molecular interaction between Rras2, BMPR2, and Smurf1.
  • Employed adeno-associated virus 9 (AAV9) for Rras2 gene delivery in vivo.

Main Results:

  • Rras2 deficiency in mice resulted in osteopenia, reduced bone strength, and impaired osteogenesis.
  • Rras2 was found to promote osteogenic differentiation and bone regeneration.
  • Rras2 stabilizes BMPR2 by inhibiting Smurf1-mediated degradation, creating a positive feedback loop with BMP signaling.
  • Restoration of Rras2 expression using AAV9 effectively rescued bone loss in osteoporotic mice.

Conclusions:

  • A critical Rras2-BMPR2 positive feedback loop regulates bone homeostasis.
  • Rras2 plays a vital role in osteoblast differentiation and bone regeneration.
  • Targeting the Rras2 pathway offers a potential therapeutic strategy for osteoporosis and Noonan syndrome.

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