A fundamental understanding of the molecular mechanism governing adult osteoprogenitors and their differentiation is essential for developing novel bone anabolic therapeutics. We have recently discovered that Hh signaling induces expression of Igf signaling components and activates Igf signaling, thus engaging in a Hh-Igf positive feedabck loop in osteoblast-lineage cells. In addition, we have identified a Hh-responsive population as critical osteoprogenitors in adult bones. In the current proposal, we will further elucidate the biochemical basis for the Hh-Igf feedback mechanism, and explore the physiological relevance of the regulatory loop in postnatal osteoprogenitors and adult bone formation. Overall, successful completion of this project will provide novel mechanistic insights about Hh-Igf signaling in adult bones, and may open new avenues for developing effective bone anabolic therapeutics.

Public Health Relevance

There continues to be a pressing need for safe and effective therapeutics that stimulates bone formation in various medical conditions. Hedgehog signaling is indispensable for osteoblast differentiation in the long bones durign embryogenesis. However, the molecular mechanisms mediating the bone-promoting function of Hh is not well understood. Moreover, the contribution of Hh signaling to adult bone homeostasis is not well defined. The current proposal explores the biochemical and functional interaction between Hh and Igf signaling, and investigates the relavance of Hh-responsive osteoprogenitors to adult bone formation. These studies are expected to provide novel insights about the mechanism and function of Hh signaling in the postnatal skeleton. Such new knowledge may provide additional avenues for developing novel bone anabolic therapeutics.

Agency
National Institute of Health (NIH)
Institute
National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK)
Type
Research Project (R01)
Project #
5R01DK111212-02
Application #
9463631
Study Section
Skeletal Biology Structure and Regeneration Study Section (SBSR)
Program Officer
Malozowski, Saul N
Project Start
2017-04-01
Project End
2018-08-31
Budget Start
2018-04-01
Budget End
2018-08-31
Support Year
2
Fiscal Year
2018
Total Cost
Indirect Cost
Name
Washington University
Department
Orthopedics
Type
Schools of Medicine
DUNS #
068552207
City
Saint Louis
State
MO
Country
United States
Zip Code
63130
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Shi, Yu; He, Guangxu; Lee, Wen-Chih et al. (2017) Gli1 identifies osteogenic progenitors for bone formation and fracture repair. Nat Commun 8:2043
Shi, Yu; Long, Fanxin (2017) Hedgehog signaling via Gli2 prevents obesity induced by high-fat diet in adult mice. Elife 6: