Effects of trabecular calcium phosphate scaffolds on stress signaling in osteoblast precursor cells

University of Tennessee Health Science Center, Memphis, TN, USA.
Biomaterials (Impact Factor: 8.31). 07/2007; 28(17):2747-53. DOI: 10.1016/j.biomaterials.2007.02.018
Source: PubMed

ABSTRACT The objective of this research was to investigate stress-signaling patterns in response to two-dimensional (2-D) and three-dimensional (3-D) calcium phosphate (CP) materials using human embryonic palatal mesenchyme cells (HEPM, CRL-1486, ATCC, Manassas, VA), an osteoblast precursor cell line. Control discs and scaffolds were fabricated from hydroxyapatite and beta tri-CP ceramics. Phospho-specific antibody cell-based ELISA technique was utilized on members of the mitogen-activated protein kinase cascade including; the extracellular signal-regulated kinases (ERK1/2), p38, c-Jun N-terminal kinase (JNK), and the anti-apoptosis mediator protein kinase B (AKT). Quantification of these signals was evaluated during the early attachment phase of osteoblast precursor cells. In this study, it was observed that 3-D CP scaffolds significantly activated the stress mediators p38 and JNK but not ERK1/2. This signal trend was matched with an up-regulation in AKT, suggesting the ability of cells to manage high stress signals in response to 3-D CP architecture and that 3-D CP scaffolds are necessary for studies simulating a natural trabecular bone organization. The absence of these signals in 2-D CP surfaces indicated the importance of local architecture conditions on cell stress response. It was concluded from this study that osteoblast precursor cells cultured in 3-D CP scaffolds experience greater stress-signaling patterns when compared to 2-D CP surfaces.

Download full-text


Available from: Joo L Ong, Aug 14, 2015
  • Source
    • "Involvement of ILK/ERK1/2 and ILK/p38 pathways in mediating the enhanced osteoblast differentiation by micro/nanotopography. Acta Biomater (2014), cells, namely extracellular signal-regulated kinase 1/2 (ERK1/2), c-Jun N-terminal kinase (JNK) and p38. More recently, an increasing number of reports have demonstrated that ERK1/2 mediates the cell response to biomaterials [12] [13] [14] [15] [16] [17], and several studies have indicated that p38 and JNK behave likewise [18] [19] [20]. With regard to nanotopography, a specific disordered nanotopography is reported to induce osteoprogenitor differentiation and regulate mesenchymal stem cell behavior though the ERK1/2 signaling [13] [16]. "
    [Show abstract] [Hide abstract]
    ABSTRACT: The hierarchical micro/nano-textured topography (MNTs) on titanium (Ti) implant surface is effective to enhance osteoblast differentiation. We have demonstrated that integrin-linked kinase (ILK) is a key underlying signal molecular and β-catenin is one of its downstream mediators in the MNT regulated osteoblast behaviors. Here we propose that mitogen activated protein kinases (MAPKs), including extracellular signal-regulated kinase 1/2 (ERK1/2), p38 and c-Jun NH2-terminal kinase (JNK), are other effectors downstream of ILK, and this study aims to confirm this. Firstly, the levels of ILK and the MAPK activity in MG63 cells on MNTs are examined by western blot. The ILK, ERK1/2 and p38 signalings are significantly up-regulated by the MNTs, whereas the JNK activity is undetectable by western blot. Then the MG63 cell morphology, proliferation and differentiation are studied in the absence and presence of the MAPK subgroup inhibitors to confirm their roles in the cell functions on the Ti surface. The MAPK subgroup inhibitors obviously change the cell shape and depress cell proliferation. Blocking the ERK1/2 or p38 signaling, but not the JNK signaling, significantly down-regulates the cell osteogenesis-related gene expression, ALP production, collagen secretion and matrix mineralization. Afterwards, the ILK expression is down-regulated using ILK specific siRNA (ILKsi) and then the MAPK activity is determined. ILKsi significantly attenuates the phosphorylated ERK1/2 and p38 levels on MNTs, explicitly demonstrating that the ERK1/2 and p38 signalings are downstream effectors of ILK. In conclusion, these data demonstrate that both ILK/ERK1/2 and ILK/p38 pathways are involved in the mechanisms mediating the enhanced osteoblast differentiation by biomaterial surface topography, hopefully directing the biomaterial modification and biofunctionalization.
    Acta biomaterialia 04/2014; 10(8). DOI:10.1016/j.actbio.2014.04.019 · 5.68 Impact Factor
  • Source
    • "The nano synthetic CaPs were purchased from OssGen, South Korea. A liquid suspension for each combination of materials was created following a previously described method [34]. Briefly, the binders used to stabilize the suspension structure included 3% high molecular weight polyvinyl alcohol, 1% v/v carboxymethylcellulose, 1% v/v ammonium polyacrylate dispersant, and 3% v/v N,N-dimethylformamide drying agent. "
    [Show abstract] [Hide abstract]
    ABSTRACT: Multiple biomimetic approaches have been attempted to accelerate the regeneration of functional bone tissue. While most synthetic scaffolds are designed to mimic the architecture of trabecular bone, in the current study, cortical bone-like extracellular matrix was regenerated in vitro within organized structures. Biphasic calcium phosphate (BCaP) and hydroxyapatite (HAp) scaffolds were developed with longitudinal microchannels (250 μm diameter) that resembled native osteons in cortical bone. BCaP and HAp scaffolds had a compressive strength of 7.61 ± 1.42 and 9.98 ± 0.61 MPa respectively. The constructs were investigated in vitro to evaluate the organization and stiffness of the extracellular matrix (ECM) formed by human fetal osteoblasts (HFObs) cultured inside the microchannels. The ECM deposited on the BCaP scaffolds was found to have a higher micro-hardness (h) (1.93 ± 0.40 GPa) than the ECM formed within the HAp microchannels (h = 0.80 ± 0.20 GPa) (p < 0.05) or native bone (h = 0.47–0.74 GPa). ECM deposition within the microchannels resembled osteoid organization and showed a significant increase in both osteoid area and thickness after 24 days (p < 0.001). These observations indicate that controlled microarchitecture, specifically cylindrical microchannels, plays a fundamental role in stimulating the appropriate cellular response aimed at recreating organized, cortical bone-like matrix. These findings open the door for researchers to develop a new generation of cortical bone scaffolds that can restore strong, organized bone.
    02/2014; 35:122–133. DOI:10.1016/j.msec.2013.10.018
  • Source
    • "Material characterization CP surfaces and scaffolds imaged by SEM are shown in Fig. 1a–d demonstrating the microstructure of HA (Fig. 1a) and TCP (Fig. 1b) surfaces and the overall architecture and rounded triangular strut configuration of the scaffolds (Fig. 1c,d). No significant morphological difference was identified between HA and TCP materials in terms of bulk design; however, micro-and nanoscale differences do exist between these materials as previously reported [15] "
    [Show abstract] [Hide abstract]
    ABSTRACT: This study investigated the in vitro effect of low-intensity pulsed ultrasound (LIPUS) on human embryonic palatal mesenchyme cells (HEPM, CRL-1486, ATCC, Manassas, VA), an osteoblast precursor cell line, during early adhesion to calcium phosphate scaffolds. Hydroxyapatite (HA) and beta-tricalcium phosphate (TCP) ceramic scaffolds were produced by a template coating method. Phospho-specific antibody cell-based ELISA (PACE) technique was utilized on stress activation proteins, including the extracellular signal-regulated kinase (ERK1/2), P38, c-Jun N-terminal kinase (JNK) and the anti-apoptosis mediator protein kinase B (PKB/AKT). Cell-based ELISAs were also performed on the membrane anchoring protein vinculin and alpha6beta4 integrin. LIPUS stimulated activation of PERK 1/2, PJNK, PP38 and vinculin in traditional two-dimensional (2-D) culture. Calcium release from the scaffolds was partially involved in the activation of PERK 1/2 when cell response was compared between culture on 2-D surfaces and three-dimensional (3-D) HA and TCP scaffolds. Effects of calcium extracted media from scaffolds alone could not account for the full activation of PJNK, PP38, PAKT, vinculin and alpha6beta4 integrin. LIPUS stimulation further increased PERK activity on TCP scaffolds corresponding with an increase in both vinculin and alpha6beta4 integrin levels. It was concluded from this study that LIPUS treatment can significantly affect stress signaling mediators and adhesion proteins in osteoblast precursor cells during the early cell-attachment phase to trabecular patterned scaffolds.
    Biomaterials 12/2007; 28(32):4788-94. DOI:10.1016/j.biomaterials.2007.06.010 · 8.31 Impact Factor
Show more