Robert F. Klees, Roman M. Salasznyk,
Scott L. Vandenberg,
Kristin P. Bennett, and George E. Plopper
Submitted to Matrix Biology
Treated hMSC Protein Overlaps: Complete supporting data for Table 1 (gene ID overlaps in treated hMSC populations).
GO Charts and Interactive Gene Ontologies: Supplemental gene ontology analysis and information.
Ln-5 only proteins: Gene ID, gene name, and gene symbol for proteins found in Ln-5 but nowhere else.
Full Text: More complete text of paper.
Raw Protein Lists: Raw data in six text files (hMSC, hOST, Ln-5 hMSC, Collagen hMSC, Vitronectin hMSC, OS Medium hMSC).
ABSTRACT
We recently reported that laminin-5, expressed by human mesenchymal stem cells (hMSC), stimulates osteogenic gene expression in
these cells in the absence of any other osteogenic stimulus. Here we employ two dimensional liquid chromatography and tandem mass
spectrometry, along with the Database for Annotation, Visualization and Integrated Discovery (DAVID), to obtain a more comprehensive
profile of the protein (and hence gene) expression changes occurring during laminin-5-induced osteogenesis of hMSC. Specifically, we
compare the protein expression profiles of undifferentiated hMSC, hMSC cultured on laminin-5 (Ln-5 hMSC), and fully differentiated
human osteoblasts (hOST) with profiles from hMSC treated with well-established osteogenic stimuli (collagen I, vitronectin, or
dexamethazone). We find a marked reduction in the number of proteins (e.g., those involved with calcium signaling and cellular
metabolism) expressed in Ln-5 hMSC compared to hMSC, consistent with our previous finding that hOST express far fewer proteins
than do their hMSC progenitors, a pattern we call “osteogenic gene focusing.” This focused set, which resembles an intermediate
stage between hMSC and mature hOST, mirrors the expression profiles of hMSC exposed to established osteogenic stimuli and
includes osteogenic extracellular matrix proteins (collagen, vitronectin) and their integrin receptors, calcium signaling proteins,
and enzymes involved in lipid metabolism. These results provide direct evidence that laminin-5 alone stimulates global changes
in gene/protein expression in hMSC that lead to commitment of these cells to the osteogenic phenotype, and that this commitment
correlates with extracellular matrix production.
Corresponding author:
George E. Plopper, Ph.D.
Assistant Professor Department of Biology
Rensselaer Polytechnic Institute
110 8 Street
Troy NY 12180-3596
(518) 276-8288 phone
(518) 276-2162 fax
ploppg@rpi.edu
http://www.rpi.edu/~ploppg
This work was supported by Grant #1R01EB002197-01 from the National Institutes of Health (to G.E.P.). We would also like to acknowledge David Moore of Siena College, who assisted with the web site.