Skeletal health relies on architectural integrity and sufficient bone mass, which are maintained through a tightly regulated equilibrium of bone resorption by osteoclasts and bone formation by osteoblasts. Genetic stu...Skeletal health relies on architectural integrity and sufficient bone mass, which are maintained through a tightly regulated equilibrium of bone resorption by osteoclasts and bone formation by osteoblasts. Genetic studies have linked the gene coding for low-density lipoprotein receptor-related protein1(Lrp1) to bone traits but whether these associations are based on a causal molecular relationship is unknown. Here, we show that Lrp1 in osteoblasts is a novel regulator of osteoclast activity and bone mass.Mice lacking Lrp1 specifically in the osteoblast lineage displayed normal osteoblast function but severe osteoporosis due to highly increased osteoclast numbers and bone resorption. Osteoblast Lrp1 limited receptor activator of NF-κB ligand(RANKL) expression in vivo and in vitro through attenuation of platelet-derived growth factor(PDGF-BB) signaling. In co-culture, Lrp1-deficient osteoblasts stimulated osteoclastogenesis in a PDGFRβ-dependent manner and in vivo treatment with the PDGFR tyrosine kinase inhibitor imatinib mesylate limited RANKL production and led to complete remission of the osteoporotic phenotype. These results identify osteoblast Lrp1 as a key regulator of osteoblast-to-osteoclast communication and bone mass through a PDGF–RANKL signaling axis in osteoblasts and open perspectives to further explore the potential of PDGF signaling inhibitors in counteracting bone loss as well as to evaluate the importance of functional LRP1 gene variants in the control of bone mass in humans.展开更多
基金supported by Deutsche Forschungsgemeinschaft grants to A.N. (Ni637/2-3), J.Hee. (GRK1459), to J.P.T. (Tu220/6-1, 6-2, Collaborative Research Centre 1149 ‘Trauma’ (INST 40/492-1)) as well as to M.A. and T.S. (AM103/15-2 and Schi504/5-2 within the FOR793)the Bundesministerium für Bildung und Forschung projects A Network on Clinics and Pathophysiology of Osteophytes and Ancylosis, Metabolic Impact on Joint and Bone Diseases (ANCYLOSS 01EC1002B, METARTHROS) to A.N.+4 种基金Tailored Magnetic Nanoparticles for Cancer Targeting project (TOMCAT 01EZ0824) to M.H.supported by NIH grant R37-HL63762the Ted Nash Longlife Foundationthe Bright Focus Foundationthe Consortium for Frontotemporal Dementia Research
文摘Skeletal health relies on architectural integrity and sufficient bone mass, which are maintained through a tightly regulated equilibrium of bone resorption by osteoclasts and bone formation by osteoblasts. Genetic studies have linked the gene coding for low-density lipoprotein receptor-related protein1(Lrp1) to bone traits but whether these associations are based on a causal molecular relationship is unknown. Here, we show that Lrp1 in osteoblasts is a novel regulator of osteoclast activity and bone mass.Mice lacking Lrp1 specifically in the osteoblast lineage displayed normal osteoblast function but severe osteoporosis due to highly increased osteoclast numbers and bone resorption. Osteoblast Lrp1 limited receptor activator of NF-κB ligand(RANKL) expression in vivo and in vitro through attenuation of platelet-derived growth factor(PDGF-BB) signaling. In co-culture, Lrp1-deficient osteoblasts stimulated osteoclastogenesis in a PDGFRβ-dependent manner and in vivo treatment with the PDGFR tyrosine kinase inhibitor imatinib mesylate limited RANKL production and led to complete remission of the osteoporotic phenotype. These results identify osteoblast Lrp1 as a key regulator of osteoblast-to-osteoclast communication and bone mass through a PDGF–RANKL signaling axis in osteoblasts and open perspectives to further explore the potential of PDGF signaling inhibitors in counteracting bone loss as well as to evaluate the importance of functional LRP1 gene variants in the control of bone mass in humans.
