title: The sclerostin-independent bone anabolic activity of intermittent PTH treatment is mediated by T-cell-produced Wnt10b.
abstract: Both blunted osteocytic production of the Wnt inhibitor sclerostin (Scl) and increased T-cell production of the Wnt ligand Wnt10b contribute to the bone anabolic activity of intermittent parathyroid hormone (iPTH) treatment. However, the relative contribution of these mechanisms is unknown. In this study, we modeled the repressive effects of iPTH on Scl production in mice by treatment with a neutralizing anti-Scl antibody (Scl-Ab) to determine the contribution of T-cell-produced Wnt10b to the Scl-independent modalities of action of iPTH. We report that combined treatment with Scl-Ab and iPTH was more potent than either iPTH or Scl-Ab alone in increasing stromal cell production of OPG, osteoblastogenesis, osteoblast life span, bone turnover, bone mineral density, and trabecular bone volume and structure in mice with T cells capable of producing Wnt10b. In T-cell-null mice and mice lacking T-cell production of Wnt10b, combined treatment increased bone turnover significantly more than iPTH or Scl-Ab alone. However, in these mice, combined treatment with Scl-Ab and iPTH was equally effective as Scl-Ab alone in increasing the osteoblastic pool, bone volume, density, and structure. These findings demonstrate that the Scl-independent activity of iPTH on osteoblasts and bone mass is mediated by T-cell-produced Wnt10b. The data provide a proof of concept of a more potent therapeutic effect of combined treatment with iPTH and Scl-Ab than either alone.
authors.affiliation: Division of Endocrinology, Metabolism and Lipids, Department of Medicine, Emory University, Atlanta, GA, USA.
authors.forename: Jau-Yi
authors.initials: JY
authors.lastname: Li
authors.forename: Lindsey D
authors.initials: LD
authors.lastname: Walker
authors.forename: Abdul Malik
authors.initials: AM
authors.lastname: Tyagi
authors.forename: Jonathan
authors.initials: J
authors.lastname: Adams
authors.forename: M Neale
authors.initials: MN
authors.lastname: Weitzmann
authors.forename: Roberto
authors.initials: R
authors.lastname: Pacifici
mesh_terms: D048868:Adaptor Proteins, Signal Transducing; D000818:Animals; D000906:Antibodies / Q000494:pharmacology; D015519:Bone Density / Q000187:drug effects; D001842:Bone and Bones / Q000187:drug effects; D005260:Female; D006023:Glycoproteins / Q000037:antagonists & inhibitors* / Q000096:biosynthesis / Q000276:immunology; D036341:Intercellular Signaling Peptides and Proteins; D051379:Mice; D010006:Osteoblasts / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects; D010281:Parathyroid Hormone / Q000008:administration & dosage*; D013601:T-Lymphocytes / Q000378:metabolism; D051153:Wnt Proteins / Q000096:biosynthesis*
chemical_list: D048868:Adaptor Proteins, Signal Transducing; D000906:Antibodies; D006023:Glycoproteins; D036341:Intercellular Signaling Peptides and Proteins; D010281:Parathyroid Hormone; C486030:Sost protein, mouse; D051153:Wnt Proteins; C102068:Wnt10b protein, mouse
keywords: ANTIBODY; BONE; PTH; SCL; T CELLS; WNT10B