Dynamic compression of chondrocyte-agarose constructs reveals new candidate mechanosensitive genes.

PLoS One 2012 17;7(5):e36964. Epub 2012 May 17.

Université Lyon 1, Univ Lyon, CNRS, FRE 3310 - Dysfonctionnement de l'Homéostasie Tissulaire et Ingénierie Thérapeutique, IBCP, Lyon, France.

Articular cartilage is physiologically exposed to repeated loads. The mechanical properties of cartilage are due to its extracellular matrix, and homeostasis is maintained by the sole cell type found in cartilage, the chondrocyte. Although mechanical forces clearly control the functions of articular chondrocytes, the biochemical pathways that mediate cellular responses to mechanical stress have not been fully characterised. The aim of our study was to examine early molecular events triggered by dynamic compression in chondrocytes. We used an experimental system consisting of primary mouse chondrocytes embedded within an agarose hydrogel; embedded cells were pre-cultured for one week and subjected to short-term compression experiments. Using Western blots, we demonstrated that chondrocytes maintain a differentiated phenotype in this model system and reproduce typical chondrocyte-cartilage matrix interactions. We investigated the impact of dynamic compression on the phosphorylation state of signalling molecules and genome-wide gene expression. After 15 min of dynamic compression, we observed transient activation of ERK1/2 and p38 (members of the mitogen-activated protein kinase (MAPK) pathways) and Smad2/3 (members of the canonical transforming growth factor (TGF)-β pathways). A microarray analysis performed on chondrocytes compressed for 30 min revealed that only 20 transcripts were modulated more than 2-fold. A less conservative list of 325 modulated genes included genes related to the MAPK and TGF-β pathways and/or known to be mechanosensitive in other biological contexts. Of these candidate mechanosensitive genes, 85% were down-regulated. Down-regulation may therefore represent a general control mechanism for a rapid response to dynamic compression. Furthermore, modulation of transcripts corresponding to different aspects of cellular physiology was observed, such as non-coding RNAs or primary cilium. This study provides new insight into how chondrocytes respond to mechanical forces.

Download full-text PDF

Source
http://journals.plos.org/plosone/article?id=10.1371/journal.pone.0036964PLOS
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC3355169PMC
January 2013
4 Reads

Publication Analysis

Top Keywords

dynamic compression
20
mechanosensitive genes
8
candidate mechanosensitive
8
mechanical forces
8
tgf-β pathways
8
chondrocytes
6
dynamic
5
compression
5
signalling molecules
4
observed transient
4
transient activation
4
compression observed
4
min dynamic
4
genome-wide gene
4
gene expression
4
activation erk1/2
4
expression min
4
molecules genome-wide
4
members mitogen-activated
4
smad2/3 members
4

References

(Supplied by CrossRef)
Cartilage tissue remodeling in response to mechanical forces.
AJ Grodzinsky et al.
Annu Rev Biomed Eng 2000
Mechanical compression modulates matrix biosynthesis in chondrocyte/agarose culture.
MD Buschmann et al.
J Cell Sci 108 (Pt 4)(Pt 1995
The effect of continuous mechanical pressure upon the turnover of articular cartilage proteoglycans in vitro.
IL Jones et al.
Clin Orthop Relat Res 1982

Similar Publications