Submitted on August 20, 2008
Revised on March 17, 2009
Accepted on March 30, 2009
Use of a three dimensional cell culture model to study airway smooth muscle / mast cell interactions in airway remodelling
Claudia C Ceresa1, Alan J. Knox2, and Simon R Johnson2*
1 University Of Nottingham
2 University of Nottingham
* To whom correspondence should be addressed. E-mail: simon.johnson{at}nottingham.ac.uk.
Increased airway smooth muscle (ASM) mass and infiltration by mast cells are key features of airway remodeling in asthma. We describe a model to investigate the relationship between ASM, extra-cellular matrix, mast cells and airway remodeling. ASM cells were cultured in a three dimensional collagen I gel (3D culture) alone or with mast cells. ASM in 3D cultures had a spindle shaped morphology and significantly lower 
-smooth muscle actin and vimentin expression examined by immunocytochemistry and western blotting than ASM cultured in monolayers on collagen I or plastic (2D). In 3D cultures, basal ASM proliferation, examined by Ki67 immunocytochemistry, was reduced to 33% (SE +/-7, p<0.05) that of 2D cultures. The presence of mast cells in co-cultures increased ASM proliferation by 1.8 fold (p<0.05). 3D culture supernatants examined by gelatin zymography contained more active MMP-2 than 2D cultures over 7 days. Functional MMP activity was examined by gel contraction. Gels contracted spontaneously over 7 days which was significantly inhibited by the MMP inhibitor ilomastat. Mast cell co-culture enhanced ASM gel contraction by 22 % (SE +/- 16, not significant). Our model shows ASM has different morphology with lower contractile protein expression and basal proliferation in 3D culture. Compared with standard techniques ASM synthetic function as shown by MMP production and activity is sustained over longer periods. The presence of mast cells in the 3D model enhanced ASM proliferation and MMP production. Our system may more accurately model airway remodeling in asthma than standard culture systems.
