WNT7B promotes bone formation in part through mTORC1.
WNT signaling has been implicated in both embryonic and postnatal bone formation. However, the pertinent WNT ligands and their downstream signaling mechanisms are not well understood. To investigate the osteogenic capacity of WNT7B and WNT5A, both normally expressed in the developing bone, we engineered mouse strains to express either protein in a Cre-dependent manner. Targeted induction of WNT7B, but not WNT5A, in the osteoblast lineage dramatically enhanced bone mass due to increased osteoblast number and activity; this phenotype began in the late-stage embryo and intensified postnatally. Similarly, postnatal induction of WNT7B in Runx2-lineage cells greatly stimulated bone formation. WNT7B activated mTORC1 through PI3K-AKT signaling. Genetic disruption of mTORC1 signaling by deleting Raptor in the osteoblast lineage alleviated the WNT7B-induced high-bone-mass phenotype. Thus, WNT7B promotes bone formation in part through mTORC1 activation.
Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, Missouri, United States of America.
Jianquan
J
Chen
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America.
Xiaolin
X
Tu
Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, Missouri, United States of America ; Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri, United States of America.
Emel
E
Esen
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America ; Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri, United States of America.
Kyu Sang
KS
Joeng
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America.
Congxin
C
Lin
Department of Surgery, Washington University School of Medicine, St. Louis, Missouri, United States of America.
Jeffrey M
JM
Arbeit
Biozentrum, University of Basel, Basel, Switzerland.
Markus A
MA
Rüegg
Biozentrum, University of Basel, Basel, Switzerland.
Michael N
MN
Hall
Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America ; Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri, United States of America ; Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America.
Liang
L
Ma
Department of Orthopaedic Surgery, Washington University School of Medicine, St. Louis, Missouri, United States of America ; Department of Medicine, Washington University School of Medicine, St. Louis, Missouri, United States of America ; Division of Biology and Biomedical Sciences, Washington University in St. Louis, St. Louis, Missouri, United States of America ; Department of Developmental Biology, Washington University School of Medicine, St. Louis, Missouri, United States of America.
Fanxin
F
Long
D000818:Animals; D002454:Cell Differentiation; D019070:Cell Lineage; D004622:Embryo, Mammalian; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D000076222:Mechanistic Target of Rapamycin Complex 1; D051379:Mice; D046912:Multiprotein Complexes / Q000096:biosynthesis / Q000235:genetics*; D010006:Osteoblasts / Q000166:cytology; D010012:Osteogenesis / Q000235:genetics*; D011518:Proto-Oncogene Proteins / Q000096:biosynthesis / Q000235:genetics*; D058570:TOR Serine-Threonine Kinases / Q000096:biosynthesis / Q000235:genetics*; D051153:Wnt Proteins / Q000096:biosynthesis / Q000235:genetics*; D060449:Wnt Signaling Pathway; D000071818:Wnt-5a Protein
D046912:Multiprotein Complexes; D011518:Proto-Oncogene Proteins; D051153:Wnt Proteins; D000071818:Wnt-5a Protein; C438615:Wnt5a protein, mouse; C095937:Wnt7b protein, mouse; D000076222:Mechanistic Target of Rapamycin Complex 1; D058570:TOR Serine-Threonine Kinases