Event Abstract

Unraveling the role of cyclic mechanical stimulation on smooth muscle cells in vitro

  • 1 CHU de Québec Research Center, Laval University, Lab. Biomaterials and Bioengineering, CRC-I, Dept Min-Met-Materials Eng, Canada
  • 2 Politecnico di Milano, Department of Electronics, Information and Bioengineering, Italy
  • 3 Politecnico di Milano, Department of Chemistry, Materials and Chemical Engineering, Italy

Introduction: In vivo cyclic stretch strongly regulates vascular smooth muscle cells (vSMCs) phenotype and behavior[1]. Thus, the development of reliable models to study the mechanisms by which mechanical forces influence vSMCs would be essential for a better understanding of the vascular biology in physio-pathological conditions. In this context, the main objective of this study was to compare 2D and 3D culture-based models of stretched vSMCs with the aim to elucidate how the environment surrounding the cells influences cellular response.

Materials and Methods: For 2D cultures, vSMCs were seeded onto UniFlex® plates as monolayers at a density of 300x103 cells/mL (Fig.1, A). For 3D cultures, cellularized collagen gels were prepared by mixing sterile collagen solution with cell suspension[2], to a final cell density of 50x105 cells/mL, and poured onto the central region experiencing uniaxial strain of UniFlex® plates (Fig.1, B). During the experiments, a regimen of 7% cyclic strain at 1 Hz was chosen to stretch the system for 2 and 5 days. 

After culture, to compare the effect of mechanical stimulation on vSMCs in both 2D and 3D models, we performed: i) western Blot analyses (WB) to detect the expression of contractile-phenotype markers (i.e. α-actin and calponin); ii) immunofluorescence analysis for staining α-actin and calponin; iii) measurements of cell alignment.

Results and Discussion: Independently of the model dimensionality (2D or 3D), vSMCs showed strain-dependent alignment: in 2D cultures, cells aligned nearly perpendicular (80°-90°) to strain direction; in 3D cultures, cells aligned parallel to strain (at an angle of ca 0°), similarly to in vivo-like conditions. No-stretched 2D and 3D cultured cells arranged in a random orientation.

In the 2D experiments, WB analyses indicated a slight downregulation of α-SM actin (Fig. 2, A) and calponin in strained vSMCs compared to static controls (Fig. 2, B). In 3D cell-gels, instead, no differences in α-SM actin expression were detected between strained samples and controls for all time points (Fig. 2, C), while calponin expression was strongly upregulated by mechanical strain after 5 days of culture (Fig. 2, D).

Immunostaining performed on both 2D and 3D models corroborated our results. These preliminary results suggest that dynamic stimulation in 2D cultures had minimal influence on the vSMC contractile phenotype, while a significant effect could be observed for 3D cultures.

Conclusions: In this study, we confirmed the important roleof mechanical stimuli on vSMCs behavior, highlighting 3D culture support can strongly affect the final response of cells. Future works will be focused on identifying the mechanisms involved in the response of vSMCs to dynamic stimulation. 

NB was awarded of a PhD Scholarship from the Italian Ministry of Education, completed with a mobility scholarship from Scuola Interpolitecnica di Dottorato, Italy. DP was awarded of a Scholarship from NSERC CREATE Program in Regenerative Medicine (www.ncprm.ulaval.ca). This work was partially supported by NSERC-Canada, CIHR-Canada, CFI-Canada, FRQ-NT-Quebec, MRI-Quebec, and MURST.

[1] Chen, L.-J., Wei, S.-Y. & Chiu, J.-J. Mechanical regulation of epigenetics in vascular biology and pathobiology. J. Cell. Mol. Med. 17, 437–448 (2013).
[2] Meghezi, S. et al. Engineering 3D Cellularized Collagen Gels for Vascular Tissue Regeneration. J. of Vis. Exp. (2015). doi:10.3791/52812.

Keywords: Hydrogel, in vitro, cell phenotype, stimuli-response

Conference: 10th World Biomaterials Congress, Montréal, Canada, 17 May - 22 May, 2016.

Presentation Type: General Session Oral

Topic: Mechanobiology of cells on biomaterials

Citation: Bono N, Pezzoli D, Levesque L, Loy C, Candiani G, Fiore G and Mantovani D (2016). Unraveling the role of cyclic mechanical stimulation on smooth muscle cells in vitro. Front. Bioeng. Biotechnol. Conference Abstract: 10th World Biomaterials Congress. doi: 10.3389/conf.FBIOE.2016.01.02620

Copyright: The abstracts in this collection have not been subject to any Frontiers peer review or checks, and are not endorsed by Frontiers. They are made available through the Frontiers publishing platform as a service to conference organizers and presenters.

The copyright in the individual abstracts is owned by the author of each abstract or his/her employer unless otherwise stated.

Each abstract, as well as the collection of abstracts, are published under a Creative Commons CC-BY 4.0 (attribution) licence (https://creativecommons.org/licenses/by/4.0/) and may thus be reproduced, translated, adapted and be the subject of derivative works provided the authors and Frontiers are attributed.

For Frontiers’ terms and conditions please see https://www.frontiersin.org/legal/terms-and-conditions.

Received: 27 Mar 2016; Published Online: 30 Mar 2016.