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Title: Morphological and proteomic analysis of early stage of osteoblast differentiation in osteoblastic progenitor cells

Journal Article · · Experimental Cell Research
 [1];  [2];  [3]; ;  [1];  [4];  [3];  [1]
  1. Population Council, 1230 York Avenue, New York, NY 10065 (United States)
  2. Orthopedic Department, Taizhou Hospital, Wenzhou Medical College, Linhai, Zhejiang 317000 (China)
  3. Proteomics Resource Center, The Rockefeller University, 1230 York Avenue, New York, NY 10065 (United States)
  4. The 2nd Affiliated Hospital, Wenzhou Medical College, Wenzhou, Zhejiang 325000 (China)

Bone remodeling relies on a dynamic balance between bone formation and resorption, mediated by osteoblasts and osteoclasts, respectively. Under certain stimuli, osteoprogenitor cells may differentiate into premature osteoblasts and further into mature osteoblasts. This process is marked by increased alkaline phosphatase (ALP) activity and mineralized nodule formation. In this study, we induced osteoblast differentiation in mouse osteoprogenitor MC3T3-E1 cells and divided the process into three stages. In the first stage (day 3), the MC3T3-E1 cell under osteoblast differentiation did not express ALP or deposit a mineralized nodule. In the second stage, the MC3T3-E1 cell expressed ALP but did not form a mineralized nodule. In the third stage, the MC3T3-E1 cell had ALP activity and formed mineralized nodules. In the present study, we focused on morphological and proteomic changes of MC3T3-E1 cells in the early stage of osteoblast differentiation - a period when premature osteoblasts transform into mature osteoblasts. We found that mean cell area and mean stress fiber density were increased in this stage due to enhanced cell spreading and decreased cell proliferation. We further analyzed the proteins in the signaling pathway of regulation of the cytoskeleton using a proteomic approach and found upregulation of IQGAP1, gelsolin, moesin, radixin, and Cfl1. After analyzing the focal adhesion signaling pathway, we found the upregulation of FLNA, LAMA1, LAMA5, COL1A1, COL3A1, COL4A6, and COL5A2 as well as the downregulation of COL4A1, COL4A2, and COL4A4. In conclusion, the signaling pathway of regulation of the cytoskeleton and focal adhesion play critical roles in regulating cell spreading and actin skeleton formation in the early stage of osteoblast differentiation.

OSTI ID:
22209892
Journal Information:
Experimental Cell Research, Vol. 316, Issue 14; Other Information: Copyright (c) 2010 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved.; Country of input: International Atomic Energy Agency (IAEA); ISSN 0014-4827
Country of Publication:
United States
Language:
English