Details

Autor(en) / Beteiligte

• Inoue, Chiyoko N.
• Ko, Young H.
• Guggino, William B.
• Forster, Hayley G.
• Epstein, Murray

Titel

Lysophosphatidic Acid and Platelet-Derived Growth Factor Synergistically Stimulate Growth of Cultured Rat Mesangial Cells

Ist Teil von

• Experimental biology and medicine (Maywood, N.J.), 1997-12, Vol.216 (3), p.370-379

Ort / Verlag

London, England: SAGE Publications

Erscheinungsjahr

1997

Quelle

MEDLINE

Beschreibungen/Notizen

• Abstract Lysophosphatidic acid (LPA) is a structurally simple, platelet-derived phospholipid, capable of eliciting a variety of physiological responses. We have demonstrated previously that LPA elicited a marked contractile response in rat mesangial cells (Inoue CN, Forster HG, Epstein M. Circ Res 77:888-896, 1995). In the present study, we examined the potential of this vasoactive substance to induce mesangial cell proliferation. Serum-starved quiescent rat mesangial cells were incubated with either LPA or in combination with platelet-derived growth factor (PDGF). DNA synthesis was assessed by [3H]thymidine incorporation after 24 hr, and cell numbers were determined at 0, 4, and 7 days. LPA- (1 nM-30 μM) stimulated mesangial cell DNA synthesis in a dose-dependent manner. The DNA synthesis stimulated by PDGF (1-100 ng/ml) was characterized by a bell-shaped response curve with a maximum at 40 ng/ml PDGF. The ability of LPA (30 μM) to synergize PDGF was observed over the entire range of PDGF concentrations (1-100 ng/ml). Under optimal concentrations of LPNPDGF (30 μM40 ng/ml, respectively), mesangial cells displayed a 67-fold increase in [3H]thymidine incorporation, and a 1.9-fold (Day 4) and 2.5-fold (Day 7) increase in cell number as compared with that of quiescent mesangial cells. With an in vitro assay with myelin basic protein as the substrate, both LPA and PDGF induced stimulation of mitogen-activated protein (MAP) kinase activity. In addition, LPA augmented PDGF-induced increase in MAP kinase activity. In summary, these results demonstrate that LPA is mitogenic alone and also acts synergistically in combination with PDGF to promote mesangial cell proliferation. We postulate that these actions of LPA have the potential to play a crucial role in the mitogenic response of mesangial cells seen in a wide array of inflammatory and thrombotic glomerular disorders.