RT Journal Article
SR Electronic
T1 Sclerostin Inhibition Reverses Skeletal Fragility in an Lrp5-Deficient Mouse Model of OPPG Syndrome
JF Science Translational Medicine
FD American Association for the Advancement of Science
SP 211ra158
OP 211ra158
DO 10.1126/scitranslmed.3006627
VO 5
IS 211
A1 Kedlaya, Rajendra
A1 Veera, Shreya
A1 Horan, Daniel J.
A1 Moss, Rachel E.
A1 Ayturk, Ugur M.
A1 Jacobsen, Christina M.
A1 Bowen, Margot E.
A1 Paszty, Chris
A1 Warman, Matthew L.
A1 Robling, Alexander G.
YR 2013
UL http://stm.sciencemag.org/content/5/211/211ra158.abstract
AB Osteoporosis pseudoglioma syndrome (OPPG) is a rare genetic disease that produces debilitating effects in the skeleton. OPPG is caused by mutations in LRP5, a WNT co-receptor that mediates osteoblast activity. WNT signaling through LRP5, and also through the closely related receptor LRP6, is inhibited by the protein sclerostin (SOST). It is unclear whether OPPG patients might benefit from the anabolic action of sclerostin neutralization therapy (an approach currently being pursued in clinical trials for postmenopausal osteoporosis) in light of their LRP5 deficiency and consequent osteoblast impairment. To assess whether loss of sclerostin is anabolic in OPPG, we measured bone properties in a mouse model of OPPG (Lrp5−/−), a mouse model of sclerosteosis (Sost−/−), and in mice with both genes knocked out (Lrp5−/−;Sost−/−). Lrp5−/−;Sost−/− mice have larger, denser, and stronger bones than do Lrp5−/− mice, indicating that SOST deficiency can improve bone properties via pathways that do not require LRP5. Next, we determined whether the anabolic effects of sclerostin depletion in Lrp5−/− mice are retained in adult mice by treating 17-week-old Lrp5−/− mice with a sclerostin antibody for 3 weeks. Lrp5+/+ and Lrp5−/− mice each exhibited osteoanabolic responses to antibody therapy, as indicated by increased bone mineral density, content, and formation rates. Collectively, our data show that inhibiting sclerostin can improve bone mass whether LRP5 is present or not. In the absence of LRP5, the anabolic effects of SOST depletion can occur via other receptors (such as LRP4/6). Regardless of the mechanism, our results suggest that humans with OPPG might benefit from sclerostin neutralization therapies.