Turnover of lymphocytes and conceptual paradigms in HIV infection
Mark B. Feinberg
Emory Vaccine Center, Atlanta, Georgia, USA.
Phone: (404) 727-4374
Fax: (404) 727-8199
View the PDF of this commentary at: https://www.the-jci.org/press/19799.pdf
BMPs and bone loss: get it through your noggin
A study by Etsuko Abe and colleagues at Mount Sinai School of Medicine in New York has revealed that the balance between the expression of the bone-building protein BMP, and the BMP inhibitor noggin, plays a crucial role in regulating bone formation and loss. The overproduction of noggin may ultimately result in the net bone loss associated with conditions such as osteoporosis. The study suggests that recombinant BMP may prove useful in reversing age-related bone loss.
Bone morphogenetic proteins (BMPs) 2 and 4 are known to regulate hair follicle growth and skeletal development. These effects are inhibited by a protein called noggin, yet little was known about the role of noggin in the differentiation of bone-building cells (osteoblasts) and adult skeletal remodeling. In an article in the September 15 issue of the Journal of Clinical Investigation, Abe and colleagues have found that noggin is expressed in osteoblasts, chondrocytes, and macrophages. Infection of preosteoblastic cells with a retrovirus containing noggin inhibited osteoblast differentiation. A transgenic mouse that overexpressed noggin in mature osteoblasts displayed dramatic osteoporosis, decreased trabecular and calvarial bone, diminished bone formation rates, and reduced osteoblast differentiation.