Temporal Expression Patterns and Corresponding Protein Inductions of Early Responsive Genes in Rabbit Bone Marrow–Derived Mesenchymal Stem Cells Under Cyclic Compressive Loading

Abstract

Our recent study suggested that cyclic compressive loading may promote chondrogenesis of rabbit bone-marrow mesenchymal stem cells (BM-MSCs) in agarose cultures through the transforming growth factor (TGF)-β signaling pathway. It has been shown that the activating protein 1 (AP-1) (JunFos) complex mediated autoinduction of TGF-ß1 and its binding activity was essential for promoting chondrogenesis of mesenchymal cells, whereas Sox9 was identified as an essential transcription factor for chondrogenesis of embryonic mesenchymal cells. The objective of this study was to examine temporal expression patterns of early responsive genes (Sox9, c-Fos, c-Jun, and TGF-ß type Ι and II receptors) and induction of their corresponding proteins in agarose culture of rabbit BM-MSCs subjected to cyclic compressive loading. The rabbit BM-MSCs were obtained from the tibias and femurs of New Zealand White rabbits. Cell-agarose constructs were made by suspending BM-MSCs in 2% agarose gel (10 7 cells/ml) for cyclic, unconfined compression tests performed in a custommade bioreactor. In the loading experiment, specimens were subjected to sinusoidal loading with a magnitude of 15% strain at a frequency of 1 hertz for 4 hours per day. Experiments were conducted for 2 consecutive days. This study showed that cyclic compressive loading promoted gene expressions of Sox9, cJun, and both TGF-ß receptors and productions of their corresponding proteins, whereas those gene expressions exhibited different temporal expression patterns among genes and between 2 days of testing. The gene expression of c-Fos was detected only in the samples subjected to 1-hour dynamic compressive loading. These findings suggest that the TGF-ß signal transduction and activities of AP-1 and Sox9 are involved in the early stage of BM-MSC chondrogenesis promoted by dynamic compressive loading.

The role of mechanical signals in regulating chondrogenesis and osteogenesis of mesenchymal stem cells

“…TGF-β1 treatment and cyclic compression were both shown to upregulate TGF-β1 gene expression, suggesting that both stimuli induce chondrogenesis of BM-MSCs through a similar pathway (Huang et al, 2004). In a follow-up study, cyclic compressive loading also promoted gene expression and protein production of two transmembrane TGF-β receptors essential for chondrogenesis of MSCs when TGF-β signalling is involved (Huang et al, 2005).…”

Cell-Derived Polymer/Extracellular Matrix Composite Scaffolds for Cartilage Regeneration, Part 1: Investigation of Cocultures and Seeding Densities for Improved Extracellular Matrix Deposition

“…17,[37][38][39][40] Bone marrow was aspirated from the tibiae of six male New Zealand White rabbits weighing 0.9-1.2 kg at the time of harvest. Marrow aspirates were then rinsed with a general medium composed of the Dulbecco's modified Eagle's medium (DMEM; Invitrogen, Carlsbad, CA), 10% FBS, and 1% penicillin-streptomycin-fungizone (Gibco, Grand Island, NY) and centrifuged to remove fat and other debris.…”

The effect of mechanical loading on osteogenesis of human dental pulp stromal cells in a novel in vitro model

“…Cyclic scaffold compression deformation at 1 Hz frequency has been general accepted as physiological loading simulations for the best mimic of chewing movement (Buschang et al 2000;Huang et al 2005;Pelaez et al 2009;Terraciano et al 2007). In this study, an The cell culture part (Fig.…”