title: Targeting lysophosphatidic acid signaling retards culture-associated senescence of human marrow stromal cells.
abstract: Marrow stromal cells (MSCs) isolated from mesenchymal tissues can propagate in vitro to some extent and differentiate into various tissue lineages to be used for cell-based therapies. Cellular senescence, which occurs readily in continual MSC culture, leads to loss of these characteristic properties, representing one of the major limitations to achieving the potential of MSCs. In this study, we investigated the effect of lysophosphatidic acid (LPA), a ubiquitous metabolite in membrane phospholipid synthesis, on the senescence program of human MSCs. We show that MSCs preferentially express the LPA receptor subtype 1, and an abrogation of the receptor engagement with the antagonistic compound Ki16425 attenuates senescence induction in continually propagated human MSCs. This anti-aging effect of Ki16425 results in extended rounds of cellular proliferation, increased clonogenic potential, and retained plasticity for osteogenic and adipogenic differentiation. Expressions of p16(Ink4a), Rb, p53, and p21(Cip1), which have been associated with cellular senescence, were all reduced in human MSCs by the pharmacological inhibition of LPA signaling. Disruption of this signaling pathway was accompanied by morphological changes such as cell thinning and elongation as well as actin filament deformation through decreased phosphorylation of focal adhesion kinase. Prevention of LPA receptor engagement also promoted ubiquitination-mediated c-Myc elimination in MSCs, and consequently the entry into a quiescent state, G(0) phase, of the cell cycle. Collectively, these results highlight the potential of pharmacological intervention against LPA signaling for blunting senescence-associated loss of function characteristic of human MSCs.
authors.affiliation: Department of Respiratory Medicine, Tohoku University Graduate School of Medicine, Sendai, Japan.
authors.forename: Masahiko
authors.initials: M
authors.lastname: Kanehira
authors.forename: Toshiaki
authors.initials: T
authors.lastname: Kikuchi
authors.forename: Shinya
authors.initials: S
authors.lastname: Ohkouchi
authors.forename: Taizou
authors.initials: T
authors.lastname: Shibahara
authors.forename: Naoki
authors.initials: N
authors.lastname: Tode
authors.forename: Arif
authors.initials: A
authors.lastname: Santoso
authors.forename: Hisayoshi
authors.initials: H
authors.lastname: Daito
authors.forename: Hiromitsu
authors.initials: H
authors.lastname: Ohta
authors.forename: Tsutomu
authors.initials: T
authors.lastname: Tamada
authors.forename: Toshihiro
authors.initials: T
authors.lastname: Nukiwa
mesh_terms: D001854:Bone Marrow Cells / Q000166:cytology; D002453:Cell Cycle; D049109:Cell Proliferation; D048430:Cell Shape; D002478:Cells, Cultured; D016922:Cellular Senescence / Q000187:drug effects*; D006801:Humans; D008246:Lysophospholipids / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D049368:Receptors, Lysophosphatidic Acid; D015398:Signal Transduction; D017154:Stromal Cells / Q000166:cytology*
chemical_list: D008246:Lysophospholipids; D049368:Receptors, Lysophosphatidic Acid; C032881:lysophosphatidic acid