Phosphatidylinositol 3-kinase/Akt plays a role in sphingosine 1-phosphate-stimulated HSP27 induction in osteoblasts

• Published in: Journal of cellular biochemistry Vol. 98; no. 5; pp. 1249 - 1256
• Main Authors: Takai, Shinji, Tokuda, Haruhiko, Matsushima-Nishiwaki, Rie, Hanai, Yoshiteru, Kato, Kanefusa, Kozawa, Osamu
• Format: Journal Article
• Language: English
• Published: Hoboken Wiley Subscription Services, Inc., A Wiley Company 01.08.2006
• Subjects: Androstadienes - pharmacology; Animals; Cell Line; Chromones - pharmacology; Glycogen Synthase Kinase 3 - metabolism; Glycogen Synthase Kinase 3 beta; heat shock protein; Heat-Shock Proteins - metabolism; Lysophospholipids - pharmacology; Mice; Morpholines - pharmacology; osteoblast; Osteoblasts - drug effects; Osteoblasts - metabolism; Phosphatidylinositol 3-Kinases - metabolism; Phosphorylation - drug effects; protein kinase; Protein Kinase Inhibitors - pharmacology; Proto-Oncogene Proteins c-akt - antagonists & inhibitors; Proto-Oncogene Proteins c-akt - metabolism; Sphingosine - analogs & derivatives; Sphingosine - pharmacology; sphingosine 1-phosphate; Time Factors
• ISSN: 0730-2312; 1097-4644
• DOI: 10.1002/jcb.20846

We previously reported that p38 mitogen‐activated protein (MAP) kinase plays a part in sphingosine 1‐phosphate‐stimulated heat shock protein 27 (HSP27) induction in osteoblast‐like MC3T3‐E1 cells. In the present study, we investigated whether phosphatidylinositol 3‐kinase (PI3K)/protein kinase B (Akt) is involved in the induction of HSP27 in these cells. Sphingosine 1‐phosphate time dependently induced the phosphorylation of Akt. Akt inhibitor, 1L‐6‐hydroxymethyl‐chiro‐inositol 2‐(R)‐2‐O‐methyl‐3‐O‐octadecylcarbonate, reduced the HSP27 induction stimulated by sphingosine 1‐phosphate. The sphingosine 1‐phosphate‐induced phosphorylation of GSK‐3β was suppressed by Akt inhibitor. The sphingosine 1‐phosphate‐induced HSP27 levels were attenuated by LY294002 or wortmannin, PI3K inhibitors. Furthermore, LY294002 or Akt inhibitor did not affect the sphingosine 1‐phosphate‐induced phosphorylation of p38 MAP kinase and SB203580, a p38 MAP kinase inhibitor, had little effect on the phosphorylation of Akt. These results suggest that PI3K/Akt plays a part in the sphingosine 1‐phosphate‐stimulated induction of HSP27, maybe independently of p38 MAP kinase, in osteoblasts. J. Cell. Biochem. 98: 1249–1256, 2006. © 2006 Wiley‐Liss, Inc.