Scientists at the School of Medicine identified a molecule in osteoclasts, IRAK-M, that is a key regulator of bone mass.

Osteoclasts are cells that play a major role in the development and remodeling of bone. They originate from the fusion of macrophages and play an important role in the loss of bone mass that leads to osteoporosis.

Osteoporosis is a serious problem worldwide. It is characterized by loss of bone density, leading to fractures in response to relatively mild trauma. Other disorders of localized bone loss include rheumatoid arthritis and periodontal disease.

The research on osteoporosis -- led by Dr. Agnès Vignery, associate professor in the Department of Orthopedics and Rehabilitation -- focused on IRAK-M (interleukin-1 receptor associated kinase M), an intracellular signaling molecule previously found only in macrophages and in circulating white blood cells.

Their theory was that if IRAK-M is maintained as macrophages fuse to form osteoclasts, it would block later steps in the signal pathway and keep osteoclasts from growing out of control.

"IRAK-M appears to be a key signaling molecule in the prevention of bone loss," says Vignery. "In normal mice the level of IRAK-M in osteoclasts is high compared to what is found in macrophages -- and bones are well maintained. Mice that lack IRAK-M develop severe osteoporosis."

The study was done with male mice, and possible association between sex hormones and the expression of IRAK-M remain to be investigated, according to Vignery. "For now, IRAK-M looks like an exciting new target for treating or preventing the devastation of osteoporosis and other localized problems of bone loss."

Yale collaborators were Dr. Hongmei Li, Dr. Esteban Cuartas, Dr. Weiguo Cui, Dr. Koichi S. Kobayashi and Howard Hughes Medical Institute investigator Dr. Richard A. Flavell who developed the mice lacking IRAK-M. Other authors were Hua Zhu Ke and Todd Crawford at Pfizer and Yongwon Choi at the University of Pennsylvania. Funding was provided by the National Institute of Dental and Craniofacial Research at the National Institutes of Health.

-- By Janet Rettig Emanuel

T H I SW E E K ' SS T O R I E S

Yale scientist has received Javits Award for study of cerebral cortex

Yale dean's dramatic successes documented in newly acquired archive

Sought: Bulldog with the right stuff to be Handsome Dan XVI

Commission on U.S. intelligence reports to President Bush

ENDOWED PROFESSORSHIPS

• Barringer named to Mellon chair in art history
  
  
• Martin assumes Woolsey chair in religious studies
  
  

Music, dance and poetry highlight Peabody's third '¡Fiesta Latina!'

Yale Opera presents Janácek tale of love and yearning

'Celebrating South Asia' features multidisciplinary scholarship

Despite political divide, U.S. not in culture war, columnist says

Research reveals role of microRNA in development of lung cancerl

Key regulator of bone cells is linked to osteoporosis

Study: Preeclampsia in pregnancy increases risks . . .

Noted Japanese filmmaker Aoyama Shinji to screen, discuss works

Workshop offers information about grants for bioscience ventures

Symposium shows how researchers are using . . .

Yale Books in Brief

---

Bulletin Home|Visiting on Campus|Calendar of Events|In the News

Bulletin Board|Classified Ads|Search Archives|Deadlines

Bulletin Staff|Public Affairs|News Releases| E-Mail Us|Yale Home

---