title: Leukemia inhibitory factor influences the fate choice of mesenchymal progenitor cells.
abstract: Osteoblasts and adipocytes derive from a common mesenchymal precursor, and in at least some circumstances, differentiation along these two lineages is inversely related. For example, we have recently observed that concomitant with inhibition of osteoblast differentiation and bone nodule formation, leukemia inhibitory factor (LIF) induces genes regulating lipid metabolism in fetal rat calvaria (RC) cell cultures. In this study, we further investigated the adipogenic capacity of LIF-treated RC cells. Quantitative analyses revealed that LIF increased the adipocyte differentiation induced by the peroxisome proliferator-activated receptor gamma agonist BRL49653 (BRL) in RC cell populations. Gene expression profiling of individual RC cell colonies in untreated cells or cells treated with LIF, BRL, or combined LIF-BRL suggested that some adipocytes arose from bipotential or other primitive precursors, including osteoprogenitors, since many colonies co-expressed osteoblast and adipocyte differentiation markers, whereas some arose from other cell pools, most likely committed preadipocytes present in the population. These analyses further suggested that LIF and BRL do not act at the same stages of the mesenchymal hierarchy, but rather that LIF modifies differentiation of precursor cells, whereas BRL acts later to favor adipocyte differentiation. Taken together, our data suggest that LIF increased adipocyte differentiation at least in part by altering the fate of osteoblastic cells and their precursors.
authors.affiliation: Department of Molecular and Medical Genetics, University of Toronto, Medical Sciences Building, Room 6233, 1 King's College Circle, Toronto, Ontario M5S 1A8, Canada.
authors.forename: Dominic
authors.initials: D
authors.lastname: Falconi
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Oizumi
authors.forename: Jane E
authors.initials: JE
authors.lastname: Aubin
mesh_terms: D017667:Adipocytes / Q000166:cytology / Q000187:drug effects; D000818:Animals; D002454:Cell Differentiation / Q000187:drug effects*; D019070:Cell Lineage / Q000187:drug effects*; D002478:Cells, Cultured; D050556:Fatty Acid-Binding Proteins / Q000235:genetics / Q000378:metabolism; D005786:Gene Expression Regulation / Q000187:drug effects; D058574:Integrin-Binding Sialoprotein; D053605:Leukemia Inhibitory Factor / Q000494:pharmacology*; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects*; D008954:Models, Biological; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D000077154:Rosiglitazone; D012795:Sialoglycoproteins / Q000235:genetics / Q000378:metabolism; D012886:Skull / Q000166:cytology / Q000187:drug effects; D045162:Thiazolidinediones / Q000494:pharmacology
chemical_list: D050556:Fatty Acid-Binding Proteins; C546872:Ibsp protein, mouse; C546873:Ibsp protein, rat; D058574:Integrin-Binding Sialoprotein; D053605:Leukemia Inhibitory Factor; C507838:Lif protein, mouse; D012333:RNA, Messenger; D012795:Sialoglycoproteins; D045162:Thiazolidinediones; D000077154:Rosiglitazone