title: The insulin-like growth factor-1 binding protein acid-labile subunit alters mesenchymal stromal cell fate.
abstract: Age-related osteoporosis is accompanied by an increase in marrow adiposity and a reduction in serum insulin-like growth factor-1 (IGF-1) and the binding proteins that stabilize IGF-1. To determine the relationship between these proteins and bone marrow adiposity, we evaluated the adipogenic potential of marrow-derived mesenchymal stromal cells (MSCs) from mice with decreased serum IGF-1 due to knockdown of IGF-1 production by the liver or knock-out of the binding proteins. We employed 10-16-week-old, liver-specific IGF-1-deficient, IGFBP-3 knock-out (BP3KO) and acid-labile subunit knock-out (ALSKO) mice. We found that expression of the late adipocyte differentiation marker peroxisome proliferator-activated receptor gamma was increased in marrow isolated from ALSKO mice. When induced with adipogenic media, MSC cultures from ALSKO mice revealed a significantly greater number of differentiated adipocytes compared with controls. MSCs from ALSKO mice also exhibited decreased alkaline-phosphatase positive colony size in cultures that were stimulated with osteoblast differentiation media. These osteoblast-like cells from ALSKO mice failed to induce osteoclastogenesis of control cells in co-culture assays, indicating that impairment of IGF-1 complex formation with ALS in bone marrow alters cell fate, leading to increased adipogenesis.
authors.affiliation: Division of Endocrinology, Diabetes and Bone Disease, Mount Sinai School of Medicine, New York, New York 10029, USA.
authors.forename: J Christopher
authors.initials: JC
authors.lastname: Fritton
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kawashima
authors.forename: Wilson
authors.initials: W
authors.lastname: Mejia
authors.forename: Hayden-Williams
authors.initials: HW
authors.lastname: Courtland
authors.forename: Sebastien
authors.initials: S
authors.lastname: Elis
authors.forename: Hui
authors.initials: H
authors.lastname: Sun
authors.forename: Yinjgie
authors.initials: Y
authors.lastname: Wu
authors.forename: Clifford J
authors.initials: CJ
authors.lastname: Rosen
authors.forename: David
authors.initials: D
authors.lastname: Clemmons
authors.forename: Shoshana
authors.initials: S
authors.lastname: Yakar
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000378:metabolism; D050156:Adipogenesis / Q000235:genetics / Q000502:physiology; D000818:Animals; D016466:CHO Cells; D002352:Carrier Proteins / Q000235:genetics / Q000378:metabolism*; D002454:Cell Differentiation / Q000235:genetics / Q000502:physiology; D002478:Cells, Cultured; D006224:Cricetinae; D003412:Cricetulus; D006023:Glycoproteins / Q000235:genetics / Q000378:metabolism*; D006801:Humans; D015151:Immunoblotting; D007334:Insulin-Like Growth Factor I / Q000378:metabolism; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000378:metabolism; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D008817:Mice, Mutant Strains; D010006:Osteoblasts / Q000166:cytology / Q000378:metabolism; D010010:Osteoclasts / Q000166:cytology / Q000378:metabolism; D016133:Polymerase Chain Reaction; D011485:Protein Binding / Q000235:genetics / Q000502:physiology
chemical_list: D002352:Carrier Proteins; D006023:Glycoproteins; C075944:insulin-like growth factor binding protein, acid labile subunit; D007334:Insulin-Like Growth Factor I