ERK Signaling Pathways Regulate the Osteogenic Differentiation of Human Mesenchymal Stem Cells on Collagen I and Vitronectin

Salasznyk, Roman M.; Klees, Robert F.; Hughlock, Mariah K.; Plopper, George E.

doi:10.1080/15419060500242836

Cited by 140 publications

(132 citation statements)

References 36 publications

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“…We have already established that signaling by the MAPK family members ERK1 and ERK2 are critical for stimulating osteogenic gene expression in hMSC [10,11], and the data presented here establish a link between FAK and ERK during hMSC differentiation. This is of course not the first report that FAK activates ERK family members, but it is the first demonstration that specific ECM proteins induce hMSC differentiation via the FAK-ERK pathway.…”

Section: Discussionsupporting

confidence: 64%

“…Cell contact with extracellular matrix (ECM) proteins plays a critical role in regulating hMSC osteogenesis [3,[9][10][11]. Specifically, this interaction triggers osteoblast-specific expression of alkaline phosphatase and osteocalcin mRNAs, and ultimately, mineralization of bone tissue in a stage-specific sequence [12,13].…”

Section: Introductionmentioning

confidence: 99%

“…Bonelike cells expressing constitutively active MEK, which controls ERK activity, increases expression of the bone protein osteocalcin. In hMSC, pharmacological inhibition of MEK diminishes ECM-induced phosphorylation of Runx2/Cbfa-1 and subsequent osteogenic differentiation [10,11]. Whether FAK controls MEK-activated MAPK signals during osteogenic differentiation in these cells is not known.…”

Section: Introductionmentioning

confidence: 99%

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Focal adhesion kinase signaling pathways regulate the osteogenic differentiation of human mesenchymal stem cells

Salasznyk

Klees

Williams

et al. 2007

Experimental Cell Research

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The intracellular signaling events controlling human mesenchymal stem cell (hMSC) differentiation into osteoblasts are not entirely understood. We recently demonstrated that contact with extracellular matrix (ECM) proteins is sufficient to induce osteogenic differentiation of hMSC through an ERKdependent pathway. We hypothesized that FAK signaling pathways provide a link between activation of ERK 1/2 by ECM, and stimulate subsequent phosphorylation of the Runx2/Cbfa-1 transcription factor that controls osteogenic gene expression. We plated hMSC on purified collagen I (COLL-I) and vitronectin (VN) in the presence or absence of FAK-specific siRNA, and assayed for phosphorylation of Runx2/Cbfa-1 as well as expression of established osteogenic differentiation markers (bone sialoprotein-2, osteocalcin, alkaline phosphatase, calcium deposition, and spectroscopically determined mineral:matrix ratio). We found that siRNA treatment reduced FAK mRNA levels by >40% and decreased ECM-mediated phosphorylation of FAK Y397 and ERK 1/2. Serine phosphorylation of Runx2/Cbfa-1 was significantly reduced after 8 days in treated cells. Finally, FAK inhibition blocked osterix transcriptional activity and the osteogenic differentiation of hMSC, as assessed by lowered expression of osteogenic genes (RT-PCR), decreased alkaline phosphatase activity, greatly reduced calcium deposition, and a lower mineral:matrix ratio after 28 days in culture. These results suggest that FAK signaling plays an important role in regulating ECMinduced osteogenic differentiation of hMSC.

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Section: Discussionsupporting

confidence: 64%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Focal adhesion kinase signaling pathways regulate the osteogenic differentiation of human mesenchymal stem cells

Salasznyk

Klees

Williams

et al. 2007

Experimental Cell Research

Self Cite

263

225

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“…Null mutations in osteonectin result in a reduced number of osteoblasts and poor bone maturation, as well as a reduction in matrix production and assembly (Boskey et al, 2003;Delany et al, 2003). Vitronectin, detected in both Ln-5 hMSC and hOST, promotes commitment of hMSC to an osteogenic lineage (Salasznyk et al, 2004a). Collectively, these results illustrate that Ln-5 is a potent inducer of several pro-osteogenic ECM proteins, and that expression of these proteins is an important hallmark of commitment to the osteogenic lineage in hMSC.…”

Section: Discussionmentioning

confidence: 99%

Laminin-5 activates extracellular matrix production and osteogenic gene focusing in human mesenchymal stem cells

et al. 2007

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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.

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“…Together, these phenomena lead to decreased colony formation and extracellular matrix synthesis, which disables cell-cell and cell-matrix signaling required for the proper differentiation of osteoprogenitor cells. 12,31,32 Multiple signaling pathways and transcription factors, such as those involving Msx2, Dlx5, and b-catenin, converge on the Runx2 gene and activate its transcription. 33 Given that osterix is a downstream transcription factor of Runx2, the inhibition of Runx2 transcription also results in reduced osterix expression.…”

Section: Discussionmentioning

confidence: 99%

Polymethylmethacrylate particles impair osteoprogenitor viability and expression of osteogenic transcription factors Runx2, osterix, and Dlx5

Chiu¹,

Smith²,

Gene³

et al. 2009

Journal Orthopaedic Research

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Polymethylmethacrylate (PMMA) particles have been shown to inhibit the differentiation of osteoprogenitor cells, but the mechanism of this inhibitory effect has not been investigated. We hypothesize that the inhibitory effects of PMMA particles involve impairment of osteoprogenitor viability and direct inhibition of transcription factors that regulate osteogenesis. We challenged MC3T3-E1 osteoprogenitors with PMMA particles and examined the effects of these materials on osteoprogenitor viability and expression of transcription factors Runx2, osterix, Dlx5, and Msx2. MC3T3-E1 cells treated with PMMA particles over a 72-h period showed a significant reduction in cell viability and proliferation as indicated by a dose-and time-dependent increase in supernatant levels of lactate dehydrogenase, an intracellular enzyme released from dead cells, a dose-dependent decrease in cell number and BrdU uptake, and the presence of large numbers of positively labeled Annexin V-stained cells. The absence of apoptotic cells on TUNEL assay indicated that cell death occurred by necrosis, not apoptosis. MC3T3-E1 cells challenged with PMMA particles during the first 6 days of differentiation in osteogenic medium showed a significant dose-dependent decrease in the RNA expression of Runx2, osterix, and Dlx5 on all days of measurement, while the RNA expression of Msx2, an antagonist of Dlx5-induced osteogenesis, remained relatively unaffected. These results indicate that PMMA particles impair osteoprogenitor viability and inhibit the expression of transcription factors that promote osteoprogenitor differentiation. 7,8 and osteogenic differentiation of human mesenchymal stem cells. 9,10 Given that osteoprogenitors are the precursors to osteoblasts, the survival and differentiation of these cells is crucial to the process of bone formation in the implant bed during exposure to wear particles.Osteoprogenitor differentiation is regulated by the transcription factors Runx2, osterix, Dlx5, and Msx2, and the transcriptional activator b-catenin. 11 Runx2 dictates the expression of key osteoblast proteins such as alkaline phosphatase, collagen, and osteocalcin, and is expressed in bone cells throughout the osteogenic lineage. 11 Osterix lies downstream of Runx2 and is required for the differentiation of pre-osteoblasts into mature osteoblasts. 11,12 Dlx5 is a homeobox domain transcription factor that also regulates osteogenesis [13][14][15] and is involved in the response of osteogenic cells to BMP-2. [16][17][18] Msx2, another homeodomain transcription factor, is a functional antagonist and repressor of Dlx5-induced osteogenesis. 19-23 b-Catenin, a transcriptional activator of the canonical Wnt signaling pathway, associates with the DNA-binding proteins TCF and LEF, and stimulates Runx2 transcription. 11,24,25 Expression of these transcription factors is normally required for the proper differentiation of osteoprogenitor cells.Our group has previously shown that PMMA particles inhibit the osteogenic differentiation of murine MC3T3-E1 ...

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ERK Signaling Pathways Regulate the Osteogenic Differentiation of Human Mesenchymal Stem Cells on Collagen I and Vitronectin

Cited by 140 publications

References 36 publications

Focal adhesion kinase signaling pathways regulate the osteogenic differentiation of human mesenchymal stem cells

Focal adhesion kinase signaling pathways regulate the osteogenic differentiation of human mesenchymal stem cells

Laminin-5 activates extracellular matrix production and osteogenic gene focusing in human mesenchymal stem cells

Polymethylmethacrylate particles impair osteoprogenitor viability and expression of osteogenic transcription factors Runx2, osterix, and Dlx5

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