Fluid flow induces COX-2 expression in MC3T3-E1 osteoblasts via a PKA signaling pathway

Wadhwa, Sunil; Choudhary, Shilpa; Voznesensky, Maria; Epstein, Miles L.; Raisz, Lawrence G.; Pilbeam, Carol C.

doi:10.1016/s0006-291x(02)02124-1

Cited by 78 publications

(57 citation statements)

References 28 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Furthermore, earlier studies also suggest the hypothesis that CREB may participate in strain-induced gene expression in endothelial cells [43]. Indeed, the PKA pathway was found to be differentially regulated following mechanical stimulation also in osteoblasts [44].…”

Section: Discussionmentioning

confidence: 83%

Mechanical loading stimulates chondrogenesis via the PKA/CREB-Sox9 and PP2A pathways in chicken micromass cultures

Juhász

Matta

Somogyi

et al. 2014

Cellular Signalling

View full text Add to dashboard Cite

Biomechanical stimuli play important roles in the formation of articular cartilage during early foetal life, and optimal mechanical load is a crucial regulatory factor of adult chondrocyte metabolism and function. In this study, we undertook to analyse mechanotransduction pathways during in vitro chondrogenesis. Chondroprogenitor cells isolated from limb buds of 4-day-old chicken embryos were cultivated as high density cell cultures for 6 days. Mechanical stimulation was carried out by a self-designed bioreactor that exerted uniaxial intermittent cyclic load transmitted by the culture medium as hydrostatic pressure and fluid shear to differentiating cells. The loading scheme (0.05 Hz, 600 Pa; for 30 min) was applied on culturing days 2 and 3, when final commitment and differentiation of chondroprogenitor cells occurred in this model. The applied mechanical load significantly augmented cartilage matrix production and elevated mRNA expression of several cartilage matrix constituents, including collagen type II and aggrecan core protein, as well as matrixproducing hyaluronan synthases through enhanced expression, phosphorylation and nuclear signals of the main chondrogenic transcription factor Sox9. Along with increased cAMP levels, a significantly enhanced protein kinase A (PKA) activity was also detected and CREB, the archetypal downstream transcription factor of PKA signalling, exhibited elevated phosphorylation levels and stronger nuclear signals in response to mechanical stimuli. All the above effects were diminished by the PKA-inhibitor H89. Inhibition of the PKA-independent cAMP-mediators Epac1 and Epac2 with HJC0197 resulted in enhanced cartilage formation, which was additive to that of the mechanical stimulation, implying that the chondrogenesispromoting effect of mechanical load was independent of Epac. At the same time, PP2A activity was reduced following mechanical load and treatments with the PP2A-inhibitor okadaic acid were able to mimic the effects of the intervention. Our results indicate that proper mechanical stimuli augment in vitro cartilage formation via promoting both Juhász and Matta et al. 3 differentiation and matrix production of chondrogenic cells, and the opposing regulation of the PKA/CREB-Sox9 and the PP2A signalling pathways is crucial in this phenomenon.

show abstract

Section: Discussionmentioning

confidence: 83%

Mechanical loading stimulates chondrogenesis via the PKA/CREB-Sox9 and PP2A pathways in chicken micromass cultures

Juhász

Matta

Somogyi

et al. 2014

Cellular Signalling

View full text Add to dashboard Cite

show abstract

“…DISCUSSION PPAR-␥ is one of the low affinity dietary lipid receptors reviewed by Rosen and Spiegelman (32). It is widely expressed in various tissues including liver and lung cells and cell lines (4,26,27,(33)(34)(35)(36). After binding a ligand (e.g.…”

Section: Fig 10mentioning

confidence: 99%

Cytosolic Phospholipase A2 Group IVα but Not Secreted Phospholipase A2 Group IIA, V, or X Induces Interleukin-8 and Cyclooxygenase-2 Gene and Protein Expression through Peroxisome Proliferator-activated Receptors γ 1 and 2 in Human Lung Cells

Pawliczak

Logun

Madara

et al. 2004

Journal of Biological Chemistry

View full text Add to dashboard Cite

show abstract

“…Various means of mechanically stimulating bone cells in vitro have been developed to simulate forces incurred in the skeleton. While none of these loading models completely replicate the stresses endured by bone cells in vivo, application of fluid shear produces many of the cellular responses considered to be anabolic in osteoblasts including release of prostaglandins [2,3], nitric oxide [4] and increased expression of cyclooxygenase-2 (COX-2) [5][6][7].…”

Section: Introductionmentioning

confidence: 99%

“…These members of the MAPK family have been implicated in the regulation of cellular growth, differentiation and apoptosis in numerous cell types [19][20][21][22] including osteoblasts [23,24]. Several studies have shown that ERK1/2 is activated by fluid shear in osteoblasts [7,25,26]. Studies have also shown that Ca 2+ i is important to ERK1/2 activation in osteoblasts [24,27], although it is unclear whether this Ca 2+ i -induced activation results from extracellular Ca 2+ entry or intracellular Ca 2+ release.…”

Section: Introductionmentioning

confidence: 99%

Activation of extracellular-signal regulated kinase (ERK1/2) by fluid shear is Ca2+- and ATP-dependent in MC3T3-E1 osteoblasts

Liu

Genetos

Shao

et al. 2008

Bone

154

138

View full text Add to dashboard Cite

To determine the role of Ca 2+ signaling in activation of the Mitogen-Activated Protein Kinase (MAPK) pathway, we subjected MC3T3-E1 pre-osteoblastic cells to inhibitors of Ca 2+ signaling during application of fluid shear stress (FSS). FSS only activated ERK1/2, rapidly inducing phosphorylation within 5 minutes of the onset of shear. Phosphorylation of ERK1/2 (pERK1/2) was significantly reduced when Ca 2+ i was chelated with BAPTA or when Ca 2+ was removed from the flow media. Inhibition of both the L-type voltage-sensitive Ca 2+ channel and the mechanosensitive cation-selective channel blocked FSS-induced pERK1/2. Inhibition of phospholipase C with U73122 significantly reduced pERK1/2. This inhibition did not result from block of intracellular Ca 2+ release, but a loss of PKC activation. Recent data suggests a role of ATP release and purinergic receptor activation in mechanotransduction. Apyrase-mediated hydrolysis of extracellular ATP completely blocked FSS-induced phosphorylation of ERK1/2, while addition of exogenous ATP to static cells mimicked the effects of FSS on pERK1/2. Two P2 receptors, P2Y 2 and P2X 7 , have been associated with the anabolic responses of bone to mechanical loading. Using both iRNA techniques and primary osteoblasts isolated from P2X 7 knockout mice, we found that the P2X 7 , but not the P2Y 2 , purinergic receptor was involved in ERK1/2 activation under FSS. These data suggest that FSS-induced ERK1/2 phosphorylation requires Ca 2+ -dependent ATP release, however both increased Ca 2+ i and PKC activation are needed for complete activation. Further, this ATP-dependent ERK1/2 phosphorylation is mediated through P2X 7 , but not P2Y 2 , purinergic receptors.

show abstract

Fluid flow induces COX-2 expression in MC3T3-E1 osteoblasts via a PKA signaling pathway

Cited by 78 publications

References 28 publications

Mechanical loading stimulates chondrogenesis via the PKA/CREB-Sox9 and PP2A pathways in chicken micromass cultures

Mechanical loading stimulates chondrogenesis via the PKA/CREB-Sox9 and PP2A pathways in chicken micromass cultures

Cytosolic Phospholipase A2 Group IVα but Not Secreted Phospholipase A2 Group IIA, V, or X Induces Interleukin-8 and Cyclooxygenase-2 Gene and Protein Expression through Peroxisome Proliferator-activated Receptors γ 1 and 2 in Human Lung Cells

Activation of extracellular-signal regulated kinase (ERK1/2) by fluid shear is Ca2+- and ATP-dependent in MC3T3-E1 osteoblasts

Contact Info

Product

Resources

About