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Boundary Stiffness Regulates Fibroblast Behavior in Collagen Gels

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Abstract

Recent studies have illustrated the profound dependence of cellular behavior on the stiffness of 2D culture substrates. The goal of this study was to develop a method to alter the stiffness cells experience in a standard 3D collagen gel model without affecting the physiochemical properties of the extracellular matrix. A device was developed utilizing compliant anchors (0.048–0.64 N m−1) to tune the boundary stiffness of suspended collagen gels in between the commonly utilized free and fixed conditions (zero and infinite stiffness boundary stiffness). We demonstrate the principle of operation with finite element analyses and a wide range of experimental studies. In all cases, boundary stiffness has a strong influence on cell behavior, most notably eliciting higher basal tension and activated force (in response to KCl) and more pronounced remodeling of the collagen matrix at higher boundary stiffness levels. Measured equibiaxial forces for gels seeded with 3 million human foreskin fibroblasts range from 0.05 to 1 mN increasing monotonically with boundary stiffness. Estimated force per cell ranges from 17 to 100 nN utilizing representative volume element analysis. This device provides a valuable tool to independently study the effect of the mechanical environment of the cell in a 3D collagen matrix.

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References

  1. Arora, P., N. Narani, and C. McCulloch. The compliance of collagen gels regulates transforming growth factor-beta induction of alpha-smooth muscle actin in fibroblasts. Am. J. Pathol. 154(3):871–882, 1999.

    PubMed  CAS  Google Scholar 

  2. Balestrini, J. L., and K. L. Billiar. Equibiaxial cyclic stretch stimulates fibroblasts to rapidly remodel fibrin. J. Biomech. 39(16):2983–2990, 2006.

    Article  PubMed  Google Scholar 

  3. Bell, E., B. Ivarsson, and C. Merrill. Production of a tissue-like structure by contraction of collagen lattices by human fibroblasts of different proliferative potential in vitro. Proc. Natl. Acad. Sci. USA 76(3):1274–1278, 1979.

    Article  PubMed  CAS  Google Scholar 

  4. Billiar, K. L., A. M. Throm, and M. T. Frey. Biaxial failure properties of planar living tissue equivalents. J. Biomed. Mater. Res. A 73(2):182–191, 2005.

    PubMed  CAS  Google Scholar 

  5. Brown, R. A., K. K. Sethi, I. Gwanmesia, D. Raemdonck, M. Eastwood, and V. Mudera. Enhanced fibroblast contraction of 3D collagen lattices and integrin expression by TGF-beta1 and -beta3: mechanoregulatory growth factors? Exp. Cell Res. 274(2):310–322, 2002.

    Article  PubMed  CAS  Google Scholar 

  6. Campbell, B., W. Clark, and J. Wang. A multi-station culture force monitor system to study cellular contractility. J. Biomech. 36(1):137–140, 2003.

    Article  PubMed  Google Scholar 

  7. Carlson, M., M. Longaker, and J. Thompson. Wound splinting regulates granulation tissue survival. J. Surg. Res. 110(1):304–309, 2003.

    Article  PubMed  Google Scholar 

  8. Chen, J., H. Li, N. Sundarraj, and J. H. Wang. Alpha-smooth muscle actin expression enhances cell traction force. Cell Motil. Cytoskeleton 64(4):248–257, 2007.

    Article  PubMed  CAS  Google Scholar 

  9. Chevallay, B., and D. Herbage. Collagen-based biomaterials as 3D scaffold for cell cultures: applications for tissue engineering and gene therapy. Med. Biol. Eng. Comput. 38(2):211–218, 2000.

    Article  PubMed  CAS  Google Scholar 

  10. Cukierman, E., R. Pankov, D. R. Stevens, and K. M. Yamada. Taking cell-matrix adhesions to the third dimension. Science 294(5547):1708–1712, 2001.

    Article  PubMed  CAS  Google Scholar 

  11. Delvoye, P., P. Wiliquet, J. L. Leveque, B. V. Nusgens, and C. M. Lapiere. Measurement of mechanical forces generated by skin fibroblasts embedded in a three-dimensional collagen gel. J. Invest. Dermatol. 97(5):898–902, 1991.

    Article  PubMed  CAS  Google Scholar 

  12. Desmouliere, A., C. Badid, M. L. Bochaton-Piallat, and G. Gabbiani. Apoptosis during wound healing, fibrocontractive diseases and vascular wall injury. Int. J. Biochem. Cell Biol. 29(1):19–30, 1997.

    Article  PubMed  CAS  Google Scholar 

  13. Desmouliere, A., A. Geinoz, F. Gabbiani, and G. Gabbiani. Transforming growth factor-beta 1 induces alpha-smooth muscle actin expression in granulation tissue myofibroblasts and in quiescent and growing cultured fibroblasts. J. Cell Biol. 122(1):103–111, 1993.

    Article  PubMed  CAS  Google Scholar 

  14. Discher, D., P. Janmey, and Y. Wang. Tissue cells feel and respond to the stiffness of their substrate. Science 310(5751):1139–1143, 2005.

    Article  PubMed  CAS  Google Scholar 

  15. Eastwood, M., D. A. McGrouther, and R. A. Brown. A culture force monitor for measurement of contraction forces generated in human dermal fibroblast cultures: evidence for cell-matrix mechanical signalling. Biochim. Biophys. Acta 1201(2):186–192, 1994.

    PubMed  CAS  Google Scholar 

  16. Eastwood, M., R. Porter, U. Khan, G. McGrouther, and R. Brown. Quantitative analysis of collagen gel contractile forces generated by dermal fibroblasts and the relationship to cell morphology. J. Cell. Physiol. 166(1):33–42, 1996.

    Article  PubMed  CAS  Google Scholar 

  17. Elsdale, T., and J. Bard. Collagen substrata for studies on cell behavior. J. Cell Biol. 54(3):626–637, 1972.

    Article  PubMed  CAS  Google Scholar 

  18. Engler, A. J., S. Sen, H. L. Sweeney, and D. E. Discher. Matrix elasticity directs stem cell lineage specification. Cell 126(4):677–689, 2006.

    Article  PubMed  CAS  Google Scholar 

  19. Fluck, J., C. Querfeld, A. Cremer, S. Niland, T. Krieg, and S. Sollberg. Normal human primary fibroblasts undergo apoptosis in three-dimensional contractile collagen gels. J. Invest. Dermatol. 110(2):153–157, 1998.

    Article  PubMed  CAS  Google Scholar 

  20. Freyman, T., I. Yannas, R. Yokoo, and L. Gibson. Fibroblast contractile force is independent of the stiffness which resists the contraction. Exp. Cell Res. 272(2):153–162, 2002.

    Article  PubMed  CAS  Google Scholar 

  21. Gabbiani, G. The myofibroblast in wound healing and fibrocontractive diseases. J. Pathol. 200(4):500–503, 2003.

    Article  PubMed  CAS  Google Scholar 

  22. Girton, T. S., T. R. Oegema, E. D. Grassl, B. C. Isenberg, and R. T. Tranquillo. Mechanisms of stiffening and strengthening in media-equivalents fabricated using glycation. J. Biomech. Eng. 122(3):216–223, 2000.

    Article  PubMed  CAS  Google Scholar 

  23. Grinnell, F. Fibroblasts, myofibroblasts, and wound contraction. J. Cell Biol. 124(4):401–404, 1994.

    Article  PubMed  CAS  Google Scholar 

  24. Grinnell, F. Fibroblast biology in three-dimensional collagen matrices. Trends Cell Biol. 13(5):264–269, 2003.

    Article  PubMed  CAS  Google Scholar 

  25. Harley, B., T. Freyman, M. Wong, and L. Gibson. A new technique for calculating individual dermal fibroblast contractile forces generated within collagen-GAG scaffolds. Biophys. J. 93(8):2911–2922, 2007.

    Article  PubMed  CAS  Google Scholar 

  26. Hinz, B., D. Mastrangelo, C. Iselin, C. Chaponnier, and G. Gabbiani. Mechanical tension controls granulation tissue contractile activity and myofibroblast differentiation. Am. J. Pathol. 159(3):1009–1020, 2001.

    PubMed  CAS  Google Scholar 

  27. Hinz, B., S. Phan, V. Thannickal, A. Galli, M. Bochaton-Piallat, and G. Gabbiani. The myofibroblast: one function, multiple origins. Am. J. Pathol. 170(6):1807–1816, 2007.

    Article  PubMed  CAS  Google Scholar 

  28. Huang, S., and D. Ingber. Cell tension, matrix mechanics, and cancer development. Cancer Cell 8(3):175–176, 2005.

    Article  PubMed  CAS  Google Scholar 

  29. Ibusuki, S., G. J. Halbesma, M. A. Randolph, R. W. Redmond, I. E. Kochevar, and T. J. Gill. Photochemically cross-linked collagen gels as three-dimensional scaffolds for tissue engineering. Tissue Eng. 13(8):1995–2001, 2007.

    Article  PubMed  CAS  Google Scholar 

  30. Ingber, D. E., D. Prusty, Z. Sun, H. Betensky, and N. Wang. Cell shape, cytoskeletal mechanics, and cell cycle control in angiogenesis. J. Biomech. 28(12):1471–1484, 1995.

    Article  PubMed  CAS  Google Scholar 

  31. Jiang, H., S. Rhee, C. H. Ho, and F. Grinnell. Distinguishing fibroblast promigratory and procontractile growth factor environments in 3-D collagen matrices. FASEB J. 22(7):2151–2160, 2008.

    Article  PubMed  CAS  Google Scholar 

  32. Ju, B. F., K.-K. Liu, S.-F. Ling, and W. Hong Ng. A novel technique for characterizing elastic properties of thin biological membrane. Mech. Mater. 34(11):749–754, 2002.

    Article  Google Scholar 

  33. Junker, J. P., C. Kratz, A. Tollback, and G. Kratz. Mechanical tension stimulates the transdifferentiation of fibroblasts into myofibroblasts in human burn scars. Burns 34(7):942–946, 2008.

    Article  PubMed  Google Scholar 

  34. Karamichos, D., R. A. Brown, and V. Mudera. Complex dependence of substrate stiffness and serum concentration on cell-force generation. J. Biomed. Mater. Res. A 78(2):407–415, 2006.

    PubMed  CAS  Google Scholar 

  35. Karamichos, D., R. A. Brown, and V. Mudera. Collagen stiffness regulates cellular contraction and matrix remodeling gene expression. J. Biomed. Mater. Res. A 83(3):887–894, 2007.

    PubMed  CAS  Google Scholar 

  36. Karamichos, D., J. Skinner, R. Brown, and V. Mudera. Matrix stiffness and serum concentration effects matrix remodelling and ECM regulatory genes of human bone marrow stem cells. J. Tissue Eng. Regen. Med. 2(2–3):97–105, 2008.

    Article  PubMed  CAS  Google Scholar 

  37. Kershaw, J. D., M. Misfeld, H. H. Sievers, M. H. Yacoub, and A. H. Chester. Specific regional and directional contractile responses of aortic cusp tissue. J. Heart Valve Dis. 13(5):798–803, 2004.

    PubMed  Google Scholar 

  38. Knapp, D., T. Tower, R. Tranquillo, and V. H. Barocas. Estimation of cell traction and migration in an isometric cell traction assay. AIChE J. 45(12):2628–2640, 1999.

    Article  CAS  Google Scholar 

  39. Knezevic, V., A. J. Sim, T. K. Borg, and J. W. Holmes. Isotonic biaxial loading of fibroblast-populated collagen gels: a versatile, low-cost system for the study of mechanobiology. Biomech. Model. Mechanobiol. 1(1):59–67, 2002.

    Article  PubMed  CAS  Google Scholar 

  40. Kolodney, M. S., and R. B. Wysolmerski. Isometric contraction by fibroblasts and endothelial cells in tissue culture: a quantitative study. J. Cell Biol. 117(1):73–82, 1992.

    Article  PubMed  CAS  Google Scholar 

  41. Legant, W. R., A. Pathak, M. T. Yang, V. S. Deshpande, R. M. McMeeking, and C. S. Chen. Microfabricated tissue gauges to measure and manipulate forces from 3D microtissues. Proc. Natl. Acad. Sci. USA 106(25):10097–10102, 2009.

    Article  PubMed  Google Scholar 

  42. Mazzolai, L., T. Pedrazzini, F. Nicoud, G. Gabbiani, H. R. Brunner, and J. Nussberger. Increased cardiac angiotensin II levels induce right and left ventricular hypertrophy in normotensive mice. Hypertension 35(4):985–991, 2000.

    PubMed  CAS  Google Scholar 

  43. Moulin, V., B. Y. Tam, G. Castilloux, F. A. Auger, M. D. O’Connor-McCourt, A. Philip, and L. Germain. Fetal and adult human skin fibroblasts display intrinsic differences in contractile capacity. J. Cell. Physiol. 188(2):211–222, 2001.

    Article  PubMed  CAS  Google Scholar 

  44. Nelson, C. M., R. P. Jean, J. L. Tan, W. F. Liu, N. J. Sniadecki, A. A. Spector, and C. S. Chen. Emergent patterns of growth controlled by multicellular form and mechanics. Proc. Natl. Acad. Sci. USA 102(33):11594–11599, 2005.

    Article  PubMed  CAS  Google Scholar 

  45. Nguyen, K. T., and J. L. West. Photopolymerizable hydrogels for tissue engineering applications. Biomaterials 23(22):4307–4314, 2002.

    Article  PubMed  CAS  Google Scholar 

  46. Nishiyama, T., N. Tominaga, K. Nakajima, and T. Hayashi. Quantitative evaluation of the factors affecting the process of fibroblast-mediated collagen gel contraction by separating the process into three phases. Coll. Relat. Res. 8(3):259–273, 1988.

    PubMed  CAS  Google Scholar 

  47. Pedersen, J. A., and M. A. Swartz. Mechanobiology in the third dimension. Ann. Biomed. Eng. 33(11):1469–1490, 2005.

    Article  PubMed  Google Scholar 

  48. Peyton, S. R., C. M. Ghajar, C. B. Khatiwala, and A. J. Putnam. The emergence of ECM mechanics and cytoskeletal tension as important regulators of cell function. Cell Biochem. Biophys. 47(2):300–320, 2007.

    Article  PubMed  CAS  Google Scholar 

  49. Redden, R. A., and E. J. Doolin. Collagen crosslinking and cell density have distinct effects on fibroblast-mediated contraction of collagen gels. Skin Res. Technol. 9(3):290–293, 2003.

    Article  PubMed  Google Scholar 

  50. Rowlands, A., P. George, and J. Cooper-White. Directing osteogenic and myogenic differentiation of MSCs: interplay of stiffness and adhesive ligand presentation. Am. J. Physiol. Cell Physiol. 295(4):C1037–C1044, 2008.

    Article  PubMed  CAS  Google Scholar 

  51. Shapira-Schweitzer, K., and D. Seliktar. Matrix stiffness affects spontaneous contraction of cardiomyocytes cultured within a PEGylated fibrinogen biomaterial. Acta Biomater. 3(1):33–41, 2007.

    Article  PubMed  CAS  Google Scholar 

  52. Tamariz, E., and F. Grinnell. Modulation of fibroblast morphology and adhesion during collagen matrix remodeling. Mol. Biol. Cell 13(11):3915–3929, 2002.

    Article  PubMed  CAS  Google Scholar 

  53. Thomopoulos, S., G. M. Fomovsky, and J. W. Holmes. The development of structural and mechanical anisotropy in fibroblast populated collagen gels. J. Biomech. Eng. 127(5):742–750, 2005.

    Article  PubMed  Google Scholar 

  54. Tomasek, J., G. Gabbiani, B. Hinz, C. Chaponnier, and R. Brown. Myofibroblasts and mechano-regulation of connective tissue remodelling. Nat. Rev. Mol. Cell Biol. 3(5):349–363, 2002.

    Article  PubMed  CAS  Google Scholar 

  55. Torres, D. S., T. M. Freyman, I. V. Yannas, and M. Spector. Tendon cell contraction of collagen-GAG matrices in vitro: effect of cross-linking. Biomaterials 21(15):1607–1619, 2000.

    Article  PubMed  CAS  Google Scholar 

  56. Walker, G., K. Masters, D. Shah, K. Anseth, and L. Leinwand. Valvular myofibroblast activation by transforming growth factor-beta: implications for pathological extracellular matrix remodeling in heart valve disease. Circ. Res. 95(3):253–260, 2004.

    Article  PubMed  CAS  Google Scholar 

  57. Zaman, M., L. Trapani, A. Sieminski, A. Siemeski, D. Mackellar, H. Gong, R. Kamm, A. Wells, D. Lauffenburger, and P. Matsudaira. Migration of tumor cells in 3D matrices is governed by matrix stiffness along with cell-matrix adhesion and proteolysis. Proc. Natl. Acad. Sci. USA 103(29):10889–10894, 2006.

    Article  PubMed  CAS  Google Scholar 

  58. Zhu, Y. K., T. Umino, X. D. Liu, H. J. Wang, D. J. Romberger, J. R. Spurzem, and S. I. Rennard. Contraction of fibroblast-containing collagen gels: initial collagen concentration regulates the degree of contraction and cell survival. In Vitro Cell Dev. Biol. Anim. 37(1):10–16, 2001.

    Article  PubMed  CAS  Google Scholar 

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Acknowledgments

The authors would like to thank Jacquelyn Youssef for her technical assistance in the laboratory. This work was supported in part by the American Heart Association Grant SDG 0535265N (KLB) and the National Institutes of Health 1R15HL087257 (KLB). The authors have no financial relationships that represent conflicts of interest.

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Correspondence to Kristen Billiar.

Appendix

Appendix

Estimation of the Force Per Cell Using the RVE Method

To estimate the average force per cell, we assume that the cells are oriented randomly in the plane of the tissue, and that each cell pulls predominantly in one direction (i.e., bipolar cells). Using the RVE method, the total force measured along one axis, F T, can be computed from the average force per cell, F C, by integration:

$$ F_{\text{T}} = \int_{{ - {\frac{\pi }{2}}}}^{{{\frac{\pi }{2}}}} {{n_{\text{E}}}R(\theta )F_{\text{C}} \cos (\theta )d\theta } $$
(A.1)

where n E is the number of cells in parallel (RVEs a cross-section), and R(θ) is the angular distribution of cells. If the distribution of cells orientations is assumed uniform (constant with θ), and we note that the integral of R(θ) = 1 by definition, then:

$$ F_{\text{T}} = n_{\text{E}} \left[ {\sin {\frac{\pi }{2}} - \sin {\frac{ - \pi }{2}}} \right]F_{\text{C}} = 2{n_{\text{E}}}F_{\text{C}}. $$
(A.2)

Thus, F C = F T/2n E in our system.

To determine the size of an RVE, the final volume of the gel is calculated by multiplying the projected area (from digital images, e.g., Fig. 8a) by the thickness (from histological sections, e.g., Fig. 8d) and is divided by the total number of cells in the gel. The number of cells (RVEs) contributing to the total force is estimated by dividing the cross-sectional area in the central region of interest perpendicular to the axis on which force is measured by the cross-sectional area of the RVE which is assumed to be a cube. As the shape of the contracted gel is roughly cruciform, the width of the region of interest is approximately half of the maximum dimension of the gel.

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John, J., Throm Quinlan, A., Silvestri, C. et al. Boundary Stiffness Regulates Fibroblast Behavior in Collagen Gels. Ann Biomed Eng 38, 658–673 (2010). https://doi.org/10.1007/s10439-009-9856-1

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