Genomic analysis of smooth muscle cells in three‐dimensional collagen matrix

Abstract

The proliferation, differentiation, and protein synthesis of vascular smooth muscle cells (SMCs) play important roles in vascular remodeling. Here, we compared the genetic programming and signaling of SMCs in collagen matrix as a three-dimensional (3-D) environment and on a two-dimensional (2-D) surface. By using DNA microarrays with 9600 genes, we showed that 77 genes were expressed more than twofold and 22 genes were less than one-half in 3-D matrix, when compared with the 2-D condition. The higher expression level of cyclin-dependent kinase inhibitor 1 (p21) in 3-D matrix suggests that p21 may be responsible for the lower proliferation rate in 3-D matrix. The expression level of collagen I was higher in 3-D matrix, suggesting that SMCs in 3-D matrix have increased matrix synthesis. In addition, SMCs in 3-D matrix had less stress fibers and focal adhesions, and a lower level of tyrosine phosphorylation of focal adhesion kinase (FAK). Overexpression of FAK attenuated the expression of p21 and collagen I in 3-D matrix, suggesting that FAK functions as a molecular switch for cell cycle regulation and matrix synthesis. The information generated in this study helps to elucidate the molecular basis of the modulation of SMC phenotypes by the extracellular matrix.

Regulation and characteristics of vascular smooth muscle cell phenotypic diversity

“…SMCs in a 3D collagen matrix are less proliferative compared with SMCs cultured on a 2D collagen matrix, and have increased TGF-β1 expression. 54 On the other hand, α-SMA levels are slightly diminished and collagen I expression is higher in the 3D system, indicating a less contractile phenotype and illustrating the complexity of the effects of the ECM on SMC phenotype. In addition, SMC responses to PDGF-B, TGF-β1 and heparin are affected by the organisation of the ECM.…”

The early- and late stages in phenotypic modulation of vascular smooth muscle cells: Differential roles for lysophosphatidic acid

“…Soluble biochemical factors, including platelet-derived growth factor (PDGF) [22][23][24][25], transforming growth factor (TGF)-β [26,27], and retinoic acid [28][29][30][31] have been shown to affect PM. Extracellular matrix molecules, such as heparin, fibrillar collagen type I, collagen type IV, and laminin have also been shown to have significant effects on PM [32][33][34][35][36][37][38][39].…”

Tissue Engineering and Regenerative Strategies to Replicate Biocomplexity of Vascular Elastic Matrix Assembly

“…SMCs, which typically exhibit a contractile phenotype within healthy, intact vascular tissues, switch to a more synthetic (i.e., proliferative and ECM-generating) phenotype when isolated and cultured in vitro. 27,28 This phenotypic switch occurs when the SMCs are cultured on either tissue culture polystyrene or within scaffolds created from one of the many natural (e.g., fibrin 29 ) or synthetic (e.g., polyglycolic acid [PGA] 30 ) polymers. While VSMCs in contact with the above scaffolds have been found to increase their production of tropoelastin precursors, 31 both at expression of elastin mRNA and its translation into protein, they abundantly and preferentially synthesize and deposit collagen, beginning at a fairly early stage in culture.…”

“…As previously mentioned, SMCs' microenvironment (e.g., biomaterial substrate) influence their phenotype, with the cells generally assuming a more synthetic, ECM-generating phenotype when isolated and cultured on most biomaterial substrates in vitro. 27,28 However, the specific responses are dependent on the substrate properties, with both the chemical composition of cellular substrates and their physical attributes (e.g., mechanics and topography) known to influence cell behavior. Thus, careful selection of cellular scaffolds that facilitate elastogenesis, and yet appropriately match vascular tissue compliance and mechanics, is important.…”