Skip to main content

Thank you for visiting nature.com. You are using a browser version with limited support for CSS. To obtain the best experience, we recommend you use a more up to date browser (or turn off compatibility mode in Internet Explorer). In the meantime, to ensure continued support, we are displaying the site without styles and JavaScript.

Cardiac valve cells and their microenvironment—insights from in vitro studies

Key Points

  • The interaction between valve cells and their microenvironment signals determine the functional output of cardiac valve tissues; cardiac valve diseases might be caused by a disruption of these interactions

  • In vitro cell culture studies can help understand cardiac valve disease pathobiology, which is enhanced by culturing cells on biomaterials that mimic the native valve cell matrix environment

  • Many biochemical signals regulate pathogenic phenotypes of cells in the valve; however, their effects are dependent on the matrix microenvironment

  • Synthetic biomaterials can be used to understand valve cell regulation by biochemical, biophysical, and other matrix-associated signals, especially related to the development of valvular diseases

  • Understanding the dynamic interplay between microenvironmental signals and valvular cell phenotypes will enable the identification of new therapies and the design of ex vivo tissue engineered valves

Abstract

During every heartbeat, cardiac valves open and close coordinately to control the unidirectional flow of blood. In this dynamically challenging environment, resident valve cells actively maintain homeostasis, but the signalling between cells and their microenvironment is complex. When homeostasis is disrupted and the valve opening obstructed, haemodynamic profiles can be altered and lead to impaired cardiac function. Currently, late stages of cardiac valve diseases are treated surgically, because no drug therapies exist to reverse or halt disease progression. Consequently, investigators have sought to understand the molecular and cellular mechanisms of valvular diseases using in vitro cell culture systems and biomaterial scaffolds that can mimic the extracellular microenvironment. In this Review, we describe how signals in the extracellular matrix regulate valve cell function. We propose that the cellular context is a critical factor when studying the molecular basis of valvular diseases in vitro, and one should consider how the surrounding matrix might influence cell signalling and functional outcomes in the valve. Investigators need to build a systems-level understanding of the complex signalling network involved in valve regulation, to facilitate drug target identification and promote in situ or ex vivo heart valve regeneration.

Access options

Rent or Buy article

Get time limited or full article access on ReadCube.

from$8.99

All prices are NET prices.

Figure 1: Valve cells and their matrix regulate tissue homeostasis and disease progression.
Figure 2: Dynamic cellular phenotypes in cardiac valve diseases.
Figure 3: Matrix signals regulate valve cell phenotypes.
Figure 4: Valve cells and the ECM microenvironment are dynamic and mutually regulated.

References

  1. 1

    Schoen, F. J. Evolving concepts of cardiac valve dynamics. Circulation 118, 1864–1880 (2008).

    Article  PubMed  PubMed Central  Google Scholar 

  2. 2

    Balachandran, K., Sucosky, P. & Yoganathan, A. P. Hemodynamics and mechanobiology of aortic valve inflammation and calcification. Int. J. Inflam. 2011, 263870 (2011).

    Article  PubMed  PubMed Central  Google Scholar 

  3. 3

    Gould, S. T., Srigunapalan, S., Simmons, C. A. & Anseth, K. S. Hemodynamic and cellular response feedback in calcific aortic valve disease. Circ. Res. 113, 186–197 (2013).

    Article  CAS  Google Scholar 

  4. 4

    Hinton, R. & Yutzey, K. E. Heart valve structure and function in development and disease. Annu. Rev. Physiol. 73, 29–46 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  5. 5

    Vesely, I. The role of elastin in aortic valve mechanics. J. Biomech. 31, 115–123 (1998).

    Article  CAS  Google Scholar 

  6. 6

    Bischoff, J. & Aikawa, E. Progenitor cells confer plasticity to cardiac valve endothelium. J. Cardiovasc. Transl. Res. 4, 710–719 (2011).

    Article  Google Scholar 

  7. 7

    Rajamannan, N. M. et al. Calcific aortic valve disease: not simply a degenerative process. Circulation 124, 1783–1791 (2011).

    Article  PubMed  PubMed Central  Google Scholar 

  8. 8

    Rabkin, E. et al. Activated interstitial myofibroblasts express catabolic enzymes and mediate matrix remodeling in myxomatous heart valves. Circulation 104, 2525–2532 (2001).

    Article  CAS  Google Scholar 

  9. 9

    Levine, R. A. & Schwammenthal, E. Ischemic mitral regurgitation on the threshold of a solution: from paradoxes to unifying concepts. Circulation 112, 745–758 (2005).

    Article  PubMed  PubMed Central  Google Scholar 

  10. 10

    Armstrong, E. J. & Bischoff, J. Heart valve development: endothelial cell signaling and differentiation. Circ. Res. 95, 459–470 (2004).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  11. 11

    Combs, M. D. & Yutzey, K. E. Heart valve development: regulatory networks in development and disease. Circ. Res. 105, 408–421 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  12. 12

    Roger, V. L. et al. Heart disease and stroke statistics—2011 update: a report from the American Heart Association. Circulation 123, e18–e209 (2011).

    Article  Google Scholar 

  13. 13

    Gharacholou, S. M., Karon, B. L., Shub, C. & Pellikka, P. A. Aortic valve sclerosis and clinical outcomes: moving toward a definition. Am. J. Med. 124, 103–110 (2011).

    Article  Google Scholar 

  14. 14

    Freeman, R. V. & Otto, C. M. Spectrum of calcific aortic valve disease: pathogenesis, disease progression, and treatment strategies. Circulation 111, 3316–3326 (2005).

    Article  Google Scholar 

  15. 15

    Otto, C. M., Lind, B. K., Kitzman, D. W., Gersh, B. J. & Siscovick, D. S. Association of aortic-valve sclerosis with cardiovascular mortality and morbidity in the elderly. N. Engl. J. Med. 341, 142–147 (1999).

    Article  CAS  Google Scholar 

  16. 16

    Bonow, R. O. et al. 2008 focused update incorporated into the ACC/AHA 2006 guidelines for the management of patients with valvular heart disease: a report of the American College of Cardiology/American Heart Association Task Force on Practice Guidelines (writing committee to revise the 1998 guidelines for the management of patients with valvular heart disease) endorsed by the Society of Cardiovascular Anesthesiologists, Society for Cardiovascular Angiography and Interventions, and Society of Thoracic Surgeons. J. Am. Coll. Cardiol. 52, e1–e142 (2008).

    Article  Google Scholar 

  17. 17

    Hutcheson, J. D., Aikawa, E. & Merryman, W. D. Potential drug targets for calcific aortic valve disease. Nat. Rev. Cardiol. 11, 218–231 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  18. 18

    Guy, T. S. & Hill, A. C. Mitral valve prolapse. Annu. Rev. Med. 63, 277–292 (2012).

    Article  CAS  Google Scholar 

  19. 19

    Miller, J. D., Weiss, R. M. & Heistad, D. D. Calcific aortic valve stenosis: methods, models, and mechanisms. Circ. Res. 108, 1392–1412 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  20. 20

    Weiss, R. M., Miller, J. D. & Heistad, D. D. Fibrocalcific aortic valve disease: opportunity to understand disease mechanisms using mouse models. Circ. Res. 113, 209–222 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  21. 21

    Sider, K. L., Blaser, M. C. & Simmons, C. A. Animal models of calcific aortic valve disease. Int. J. Inflam. 2011, 18 (2011).

    Article  Google Scholar 

  22. 22

    Rajamannan, N. M. et al. Human aortic valve calcification is associated with an osteoblast phenotype. Circulation 107, 2181–2184 (2003).

    Article  PubMed  PubMed Central  Google Scholar 

  23. 23

    Sainger, R. et al. Human myxomatous mitral valve prolapse: role of bone morphogenetic protein 4 in valvular interstitial cell activation. J. Cell Physiol. 227, 2595–2604 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  24. 24

    Santos, E., Orive, G., Hernández, R. M. & Pedraz, J. L. Cell-Biomaterial interaction: strategies to mimic the extracellular matrix [online], (2011).

    Google Scholar 

  25. 25

    Liu, A. C., Joag, V. R. & Gotlieb, A. I. The emerging role of valve interstitial cell phenotypes in regulating heart valve pathobiology. Am. J. Pathol. 171, 1407–1418 (2007).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  26. 26

    Leopold, J. A. Cellular mechanisms of aortic valve calcification. Circ. Cardiovasc. Interv. 5, 605–614 (2012).

    Article  PubMed  PubMed Central  Google Scholar 

  27. 27

    Bertazzo, S. et al. Nano-analytical electron microscopy reveals fundamental insights into human cardiovascular tissue calcification. Nat. Mater. 12, 576–583 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  28. 28

    Pohle, K. et al. Progression of aortic valve calcification: association with coronary atherosclerosis and cardiovascular risk factors. Circulation 104, 1927–1932 (2001).

    Article  CAS  Google Scholar 

  29. 29

    Cowell, S. J. et al. A randomized trial of intensive lipid-lowering therapy in calcific aortic stenosis. N. Engl. J. Med. 352, 2389–2397 (2005).

    Article  CAS  Google Scholar 

  30. 30

    Walker, G. A., Masters, K. S., Shah, D. N., Anseth, K. S. & Leinwand, L. A. Valvular myofibroblast activation by transforming growth factor-beta1. Circ. Res. 95, 253–260 (2004).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  31. 31

    Paranya, G. et al. Aortic valve endothelial cells undergo transforming growth factor-beta-mediated and non-transforming growth factor-beta-mediated transdifferentiation in vitro. Am. J. Pathol. 159, 1335–1343 (2001).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  32. 32

    Pho, M. et al. Cofilin is a marker of myofibroblast differentiation in cells from porcine aortic cardiac valves. Am. J. Physiol. Heart Circ. Physiol. 294, H1767–H1778 (2008).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  33. 33

    Egan, K. P., Kim, J.-H., Mohler, E. R. & Pignolo, R. J. Role for circulating osteogenic precursor cells in aortic valvular disease. Arterioscler. Thromb. Vasc. Biol. 31, 2965–2971 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  34. 34

    Gossl, M. et al. Role of circulating osteogenic progenitor cells in calcific aortic stenosis. J. Am. Coll. Cardiol. 60, 1945–1953 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  35. 35

    Gooch, J. L., Gorin, Y., Zhang, B.-X. & Abboud, H. E. Involvement of calcineurin in transforming growth factor-beta-mediated regulation of extracellular matrix accumulation. J. Biol. Chem. 279, 15561–15570 (2004).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  36. 36

    Kagami, S., Border, W. A., Miller, D. E. & Noble, N. A. Angiotensin II stimulates extracellular matrix protein synthesis through induction of transforming growth factor-beta expression in rat glomerular mesangial cells. J. Clin. Invest. 93, 2431–2437 (1994).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  37. 37

    Hinz, B. The myofibroblast: paradigm for a mechanically active cell. J. Biomech. 43, 146–155 (2010).

    Article  PubMed  PubMed Central  Google Scholar 

  38. 38

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

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  39. 39

    Henderson, N. C. & Iredale, J. P. Liver fibrosis: cellular mechanisms of progression and resolution. Clin. Sci. (Lond.) 112, 265–280 (2007).

    Article  CAS  Google Scholar 

  40. 40

    King, T. E., Pardo, A. & Selman, M. Idiopathic pulmonary fibrosis. Lancet 378, 1949–1961 (2011).

    Article  PubMed  PubMed Central  Google Scholar 

  41. 41

    Liu, Y. Cellular and molecular mechanisms of renal fibrosis. Nat. Rev. Nephrol. 7, 684–696 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  42. 42

    Santiago, J.-J. et al. Cardiac fibroblast to myofibroblast differentiation in vivo and in vitro: Expression of focal adhesion components in neonatal and adult rat ventricular myofibroblasts. Dev. Dyn. 239, 1573–1584 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  43. 43

    Hinz, B. et al. Recent developments in myofibroblast biology: paradigms for connective tissue remodeling. Am. J. Pathol. 180, 1340–1355 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  44. 44

    Wynn, T. A. & Ramalingam, T. R. Mechanisms of fibrosis: therapeutic translation for fibrotic disease. Nat. Med. 18, 1028–1040 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  45. 45

    Desmoulière, A., Redard, M., Darby, I. & Gabbiani, G. Apoptosis mediates the decrease in cellularity during the transition between granulation tissue and scar. Am. J. Pathol. 146, 56–66 (1995).

    PubMed  PubMed Central  Google Scholar 

  46. 46

    Grinnell, F., Zhu, M., Carlson, M. A. & Abrams, J. M. Release of mechanical tension triggers apoptosis of human fibroblasts in a model of regressing granulation tissue. Exp. Cell Res. 248, 608–619 (1999).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  47. 47

    Krizhanovsky, V. et al. Senescence of activated stellate cells limits liver fibrosis. Cell 134, 657–667 (2008).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  48. 48

    Kisseleva, T. et al. Myofibroblasts revert to an inactive phenotype during regression of liver fibrosis. Proc. Natl Acad. Sci. USA 109, 9448–9453 (2012).

    Article  PubMed  PubMed Central  Google Scholar 

  49. 49

    Wang, H., Haeger, S. M., Kloxin, A. M., Leinwand, L. A. & Anseth, K. S. Redirecting valvular myofibroblasts into dormant fibroblasts through light-mediated reduction in substrate modulus. PLoS ONE 7, e39969 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  50. 50

    Monzack, E. L. & Masters, K. S. Can valvular interstitial cells become true osteoblasts? A side-by-side comparison. J. Heart Valve Dis. 20, 449–463 (2011).

    PubMed  PubMed Central  Google Scholar 

  51. 51

    Cloyd, K. L. et al. Characterization of porcine aortic valvular interstitial cell 'calcified' nodules. PLoS ONE 7, e48154 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  52. 52

    Alexopoulos, A. et al. Bone regulatory factors NFATc1 and Osterix in human calcific aortic valves. Int. J. Cardiol. 139, 142–149 (2010).

    Article  PubMed  PubMed Central  Google Scholar 

  53. 53

    Miller, J. D. et al. Evidence for active regulation of pro-osteogenic signaling in advanced aortic valve disease. Arterioscler. Thromb. Vasc. Biol. 30, 2482–2486 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  54. 54

    Yang, X. et al. Bone morphogenic protein 2 induces Runx2 and osteopontin expression in human aortic valve interstitial cells: role of Smad1 and extracellular signal-regulated kinase 1/2. J. Thorac. Cardiovasc. Surg. 138, 1008–1015 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  55. 55

    Balachandran, K., Sucosky, P., Jo, H. & Yoganathan, A. P. Elevated cyclic stretch induces aortic valve calcification in a bone morphogenic protein-dependent manner. Am. J. Pathol. 177, 49–57 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  56. 56

    Mohler, E., Gannon, F., Reynolds, C., Zimmerman, R., Keane, M. G., Kaplan, F. S. Bone formation and inflammation in cardiac valves. Circulation 103, 1522–1528 (2001).

    Article  PubMed  PubMed Central  Google Scholar 

  57. 57

    Yip, C. Y. Y., Chen, J.-H., Zhao, R. & Simmons, C. A. Calcification by valve interstitial cells is regulated by the stiffness of the extracellular matrix. Arterioscler. Thromb. Vasc. Biol. 29, 936–942 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  58. 58

    Chen, J.-H., Yip, C. Y. Y., Sone, E. D. & Simmons, C. A. Identification and characterization of aortic valve mesenchymal progenitor cells with robust osteogenic calcification potential. Am. J. Pathol. 174, 1109–1119 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  59. 59

    Jian, B., Narula, N., Li, Q.-y., Mohler, E. R. III & Levy, R. J. Progression of aortic valve stenosis: TGF-β1 is present in calcified aortic valve cusps and promotes aortic valve interstitial cell calcification via apoptosis. Ann. Thorac. Surg. 75, 457–465 (2003).

    Article  PubMed  PubMed Central  Google Scholar 

  60. 60

    Wang, H., Sridhar, B., Leinwand, L. A. & Anseth, K. S. Characterization of cell subpopulations expressing progenitor cell markers in porcine cardiac valves. PLoS ONE 8, e69667 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  61. 61

    Benton, J., Kern, H. B., Leinwand, L. A., Mariner, P. D., Anseth, K. S. Statins block calcific nodule formation of valvular interstitial cells by inhibiting alpha-smooth muscle actin expression. Arterioscler. Thromb. Vasc. Biol. 29, 1950–1957 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  62. 62

    Rajamannan, N. M. et al. Calcified rheumatic valve neoangiogenesis is associated with vascular endothelial growth factor expression and osteoblast-like bone formation. Circulation 111, 3296–3301 (2005).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  63. 63

    Caira, F. C. et al. Human degenerative valve disease is associated with up-regulation of low-density lipoprotein receptor-related protein 5 receptor-mediated bone formation. J. Am. Coll. Cardiol 47, 1707–1712 (2006).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  64. 64

    Mahler, G. J., Farrar, E. J. & Butcher, J. T. Inflammatory cytokines promote mesenchymal transformation in embryonic and adult valve endothelial cells. Arterioscler. Thromb. Vasc. Biol. 33, 121–130 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  65. 65

    Sewell-Loftin, M. K. et al. Myocardial contraction and hyaluronic acid mechanotransduction in epithelial-to-mesenchymal transformation of endocardial cells. Biomaterials 35, 2809–2815 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  66. 66

    Paruchuri, S. et al. Human pulmonary valve progenitor cells exhibit endothelial/mesenchymal plasticity in response to vascular endothelial growth factor-a and transforming growth factor-β2. Circ. Res. 99, 861–869 (2006).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  67. 67

    Kaden, J. J. et al. Interleukin-1 beta promotes matrix metalloproteinase expression and cell proliferation in calcific aortic valve stenosis. Atherosclerosis 170, 205–211 (2003).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  68. 68

    Kaden, J. J. et al. Tumor necrosis factor alpha promotes an osteoblast-like phenotype in human aortic valve myofibroblasts: a potential regulatory mechanism of valvular calcification. Int. J. Mol. Med. 16, 869–872 (2005).

    CAS  PubMed  PubMed Central  Google Scholar 

  69. 69

    Nadlonek, N. et al. Interleukin-1 Beta induces an inflammatory phenotype in human aortic valve interstitial cells through nuclear factor kappa Beta. Ann. Thorac. Surg. 96, 155–162 (2013).

    Article  PubMed  PubMed Central  Google Scholar 

  70. 70

    Sunami, Y. et al. Hepatic activation of IKK/NFkappaB signaling induces liver fibrosis via macrophage-mediated chronic inflammation. Hepatology 56, 1117–1128 (2012).

    Article  CAS  Google Scholar 

  71. 71

    Bodas, M. & Vij, N. The NF-kappaB signaling in cystic fibrosis lung disease: pathophysiology and therapeutic potential. Discov. Med. 9, 346–356 (2010).

    PubMed  PubMed Central  Google Scholar 

  72. 72

    Stephan, M. T., Moon, J. J., Um, S. H., Bershteyn, A. & Irvine, D. J. Therapeutic cell engineering with surface-conjugated synthetic nanoparticles. Nat. Med. 16, 1035–1041 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  73. 73

    Butcher, J. T. & Nerem, R. M. Valvular endothelial cells and the mechanoregulation of valvular pathology. Phil. Trans. R. Soc. B Biol. Sci. 362, 1445–1457 (2007).

    Article  CAS  Google Scholar 

  74. 74

    Richards, J. et al. Side-specific endothelial-dependent regulation of aortic valve calcification: interplay of hemodynamics and nitric oxide signaling. Am. J. Pathol. 182, 1922–1931 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  75. 75

    Gould, S. T., Matherly, E. E., Smith, J. N., Heistad, D. D. & Anseth, K. S. The role of valvular endothelial cell paracrine signaling and matrix elasticity on valvular interstitial cell activation. Biomaterials 35, 3596–3606 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  76. 76

    Yip, C. Y., Blaser, M. C., Mirzaei, Z., Zhong, X. & Simmons, C. A. Inhibition of pathological differentiation of valvular interstitial cells by c-type natriuretic peptide. Arterioscler. Thromb. Vasc. Biol. 31, 1881–1889 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  77. 77

    Chester, A. H. Endothelin-1 and the aortic valve. Curr. Vasc. Pharmacol. 3, 353–357 (2005).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  78. 78

    Leask, A. & Abraham, D. J. TGF-beta signaling and the fibrotic response. FASEB J. 18, 816–827 (2004).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  79. 79

    Clark-Greuel, J. N. et al. Transforming growth factor-beta1 mechanisms in aortic valve calcification: increased alkaline phosphatase and related events. Ann. Thorac. Surg. 83, 946–953 (2007).

    Article  PubMed  PubMed Central  Google Scholar 

  80. 80

    Dweck, M. R., Boon, N. A. & Newby, D. E. Calcific aortic stenosis: a disease of the valve and the myocardium. J. Am. Coll. Cardiol. 60, 1854–1863 (2012).

    Article  PubMed  PubMed Central  Google Scholar 

  81. 81

    Horowitz, J. C. et al. Combinatorial activation of FAK and AKT by transforming growth factor-beta1 confers an anoikis-resistant phenotype to myofibroblasts. Cell. Signal. 19, 761–771 (2007).

    Article  CAS  Google Scholar 

  82. 82

    Thannickal, V. J. et al. Myofibroblast differentiation by transforming growth factor-beta1 is dependent on cell adhesion and integrin signaling via focal adhesion kinase. J. Biol. Chem. 278, 12384–12389 (2003).

    Article  CAS  Google Scholar 

  83. 83

    Meyer-Ter-Vehn, T. et al. p38 Inhibitors prevent TGF-beta-induced myofibroblast transdifferentiation in human tenon fibroblasts. Invest. Ophthalmol. Vis. Sci. 47, 1500–1509 (2006).

    Article  Google Scholar 

  84. 84

    O'Brien, K. D. et al. Apolipoproteins B, (a), and E accumulate in the morphologically early lesion of 'degenerative' valvular aortic stenosis. Arterioscler. Thromb. Vasc. Biol. 16, 523–532 (1996).

    Article  CAS  Google Scholar 

  85. 85

    Demer, L. L. & Tintut, Y. Inflammatory, metabolic, and genetic mechanisms of vascular calcification. Arterioscler. Thromb. Vasc. Biol. 34, 715–723 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  86. 86

    Leask, A. Potential therapeutic targets for cardiac fibrosis: TGFβ, angiotensin, endothelin, CCN2, and PDGF, partners in fibroblast activation. Circ. Res. 106, 1675–1680 (2010).

    Article  CAS  Google Scholar 

  87. 87

    Geirsson, A. et al. Modulation of transforming growth factor-beta signaling and extracellular matrix production in myxomatous mitral valves by angiotensin II receptor blockers. Circulation 126, S189–S197 (2012).

    Article  CAS  Google Scholar 

  88. 88

    Miller, J. D. et al. Dysregulation of antioxidant mechanisms contributes to increased oxidative stress in calcific aortic valvular stenosis in humans. J. Am. Coll. Cardiol. 52, 843–850 (2008).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  89. 89

    Boström, K. I., Rajamannan, N. M. & Towler, D. A. The regulation of valvular and vascular sclerosis by osteogenic morphogens. Circ. Res. 109, 564–577 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  90. 90

    Cushing, M. C., Mariner, P. D., Liao, J.-T., Sims, E. A. & Anseth, K. S. Fibroblast growth factor represses Smad-mediated myofibroblast activation in aortic valvular interstitial cells. FASEB J. 22, 1769–1777 (2008).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  91. 91

    Rothman, R. B. et al. Evidence for possible involvement of 5-HT2B receptors in the cardiac valvulopathy associated with fenfluramine and other serotonergic medications. Circulation 102, 2836–2841 (2000).

    Article  CAS  Google Scholar 

  92. 92

    Hutcheson, J. D., Ryzhova, L. M., Setola, V. & Merryman, W. D. 5-HT(2B) antagonism arrests non-canonical TGF-beta1-induced valvular myofibroblast differentiation. J. Mol. Cell. Cardiol. 53, 707–714 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  93. 93

    Hynes, R. O. The extracellular matrix: not just pretty fibrils. Science 326, 1216–1219 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  94. 94

    Boudreau, N. J. & Jones, P. L. Extracellular matrix and integrin signalling: the shape of things to come. Biochem. J. 339, 481–488 (1999).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  95. 95

    Kim, S.-H., Turnbull, J. & Guimond, S. Extracellular matrix and cell signalling: the dynamic cooperation of integrin, proteoglycan and growth factor receptor. J. Endocrinol. 209, 139–151 (2011).

    Article  CAS  Google Scholar 

  96. 96

    Schwartz, M. A. Integrins and extracellular matrix in mechanotransduction. Cold Spring Harb. Perspect. Biol. 2, 17 (2010).

    Article  CAS  Google Scholar 

  97. 97

    Dalby, M. J., Gadegaard, N. & Oreffo, R. O. C. Harnessing nanotopography and integrin-matrix interactions to influence stem cell fate. Nat. Mater. 13, 558–569 (2014).

    Article  CAS  Google Scholar 

  98. 98

    Gilbert, P. M. et al. Substrate elasticity regulates skeletal muscle stem cell self-renewal in culture. Science 329, 1078–1081 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  99. 99

    Wang, H., Tibbitt, M. W., Langer, S. J., Leinwand, L. A. & Anseth, K. S. Hydrogels preserve native phenotypes of valvular fibroblasts through an elasticity-regulated PI3K/AKT pathway. Proc. Natl Acad. Sci. USA 110, 19336–19341 (2013).

    Article  CAS  Google Scholar 

  100. 100

    Benton, J. A., Kern, H. B. & Anseth, K. S. Substrate properties influence calcification in valvular interstitial cell culture. J. Heart Valve Dis. 17, 689–699 (2008).

    PubMed  PubMed Central  Google Scholar 

  101. 101

    Baker, B. M. & Chen, C. S. Deconstructing the third dimension—how 3D culture microenvironments alter cellular cues. J. Cell Sci. 125, 3015–3024 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  102. 102

    Wiltz, D. et al. Extracellular matrix organization, structure, and function [online], (2013).

    Book  Google Scholar 

  103. 103

    Moraes, C. et al. Microdevice array-based identification of distinct mechanobiological response profiles in layer-specific valve interstitial cells. Integr. Biol. 5, 673–680 (2013).

    Article  CAS  Google Scholar 

  104. 104

    Cushing, M. C., Liao, J. T. & Anseth, K. S. Activation of valvular interstitial cells is mediated by transforming growth factor-beta1 interactions with matrix molecules. Matrix Biol. 24, 428–437 (2005).

    Article  CAS  Google Scholar 

  105. 105

    Gu, X. & Masters, K. S. Regulation of valvular interstitial cell calcification by adhesive peptide sequences. J. Biomed. Mater. Res. A 93, 1620–1630 (2010).

    PubMed  PubMed Central  Google Scholar 

  106. 106

    Chen, J.-H. & Simmons, C. A. Cell-matrix interactions in the pathobiology of calcific aortic valve disease: critical roles for matricellular, matricrine, and matrix mechanics cues. Circ. Res. 108, 1510–1524 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  107. 107

    Gupta, V., Werdenberg, J. A., Blevins, T. L. & Grande-Allen, K. J. Synthesis of glycosaminoglycans in differently loaded regions of collagen gels seeded with valvular interstitial cells. Tissue Eng. 13, 41–49 (2007).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  108. 108

    Butcher, J. T. & Nerem, R. M. Porcine aortic valve interstitial cells in three-dimensional culture: comparison of phenotype with aortic smooth muscle cells. J. Heart Valve Dis. 13, 478–485 (2004).

    PubMed  Google Scholar 

  109. 109

    Grande-Allen, K. J. et al. Glycosaminoglycan synthesis and structure as targets for the prevention of calcific aortic valve disease. Cardiovasc. Res. 76, 19–28 (2007).

    Article  CAS  Google Scholar 

  110. 110

    Eckert, C. E. et al. On the biomechanical role of glycosaminoglycans in the aortic heart valve leaflet. Acta Biomater. 9, 4653–4660 (2013).

    Article  CAS  Google Scholar 

  111. 111

    Cushing, M. C., Liao, J. T., Jaeggli, M. P. & Anseth, K. S. Material-based regulation of the myofibroblast phenotype. Biomaterials 28, 3378–3387 (2007).

    Article  CAS  Google Scholar 

  112. 112

    Rodriguez, K. J. & Masters, K. S. Regulation of valvular interstitial cell calcification by components of the extracellular matrix. J. Biomed. Mater. Res. A 90, 1043–1053 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  113. 113

    Powell, A. K., Yates, E. A., Fernig, D. G. & Turnbull, J. E. Interactions of heparin/heparan sulfate with proteins: appraisal of structural factors and experimental approaches. Glycobiology 14, 17R–30R (2004).

    Article  CAS  Google Scholar 

  114. 114

    Masters, K. S., Shah, D. N., Leinwand, L. A. & Anseth, K. S. Crosslinked hyaluronan scaffolds as a biologically active carrier for valvular interstitial cells. Biomaterials 26, 2517–2525 (2005).

    Article  CAS  Google Scholar 

  115. 115

    Duan, B., Hockaday, L. A., Kapetanovic, E., Kang, K. H. & Butcher, J. T. Stiffness and adhesivity control aortic valve interstitial cell behavior within hyaluronic acid based hydrogels. Acta Biomater. 9, 7640–7650 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  116. 116

    Shah, D. N., Recktenwall-Work, S. M. & Anseth, K. S. The effect of bioactive hydrogels on the secretion of extracellular matrix molecules by valvular interstitial cells. Biomaterials 29, 2060–2072 (2008).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  117. 117

    Cuff, C. A. et al. The adhesion receptor CD44 promotes atherosclerosis by mediating inflammatory cell recruitment and vascular cell activation. J. Clin. Invest. 108, 1031–1040 (2001).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  118. 118

    Misra, S., Toole, B. P. & Ghatak, S. Hyaluronan constitutively regulates activation of multiple receptor tyrosine kinases in epithelial and carcinoma cells. J. Biol. Chem. 281, 34936–34941 (2006).

    Article  CAS  Google Scholar 

  119. 119

    Tseng, H. & Grande-Allen, K. J. Elastic fibers in the aortic valve spongiosa: a fresh perspective on its structure and role in overall tissue function. Acta Biomater. 7, 2101–2108 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  120. 120

    Hinton, R. B. et al. Elastin haploinsufficiency results in progressive aortic valve malformation and latent valve disease in a mouse model. Circ. Res. 107, 549–557 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  121. 121

    Hinton, R. B. et al. Extracellular matrix remodeling and organization in developing and diseased aortic valves. Circ. Res. 98, 1431–1438 (2006).

    Article  CAS  Google Scholar 

  122. 122

    Simionescu, A., Simionescu, D. T. & Vyavahare, N. R. Osteogenic responses in fibroblasts activated by elastin degradation products and transforming growth factor-β1: role of myofibroblasts in vascular calcification. Am. J. Pathol. 171, 116–123 (2007).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  123. 123

    Steinhoff, G. et al. Tissue engineering of pulmonary heart valves on allogenic acellular matrix conduits: in vivo restoration of valve tissue. Circulation 102 (Suppl. 3), III50–III55 (2000).

    CAS  PubMed  Google Scholar 

  124. 124

    Cebotari, S. et al. Clinical application of tissue engineered human heart valves using autologous progenitor cells. Circulation 114 (Suppl.), I132–I137 (2006).

    PubMed  Google Scholar 

  125. 125

    Wong, M. L. & Griffiths, L. G. Immunogenicity in xenogeneic scaffold generation: antigen removal vs. decellularization. Acta Biomater. 10, 1806–1816 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  126. 126

    Gould, S. T., Darling, N. J. & Anseth, K. S. Small peptide functionalized thiol-ene hydrogels as culture substrates for understanding valvular interstitial cell activation and de novo tissue deposition. Acta Biomater. 8, 3201–3209 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  127. 127

    Schmedlen, R. H., Masters, K. S. & West, J. L. Photocrosslinkable polyvinyl alcohol hydrogels that can be modified with cell adhesion peptides for use in tissue engineering. Biomaterials 23, 4325–4332 (2002).

    Article  CAS  Google Scholar 

  128. 128

    Tibbitt, M. W. & Anseth, K. S. Hydrogels as extracellular matrix mimics for 3D cell culture. Biotechol. Bioeng. 103, 655–663 (2009).

    Article  CAS  Google Scholar 

  129. 129

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

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  130. 130

    Benton, J. A., Fairbanks, B. D. & Anseth, K. S. Characterization of valvular interstitial cell function in three dimensional matrix metalloproteinase degradable PEG hydrogels. Biomaterials 30, 6593–6603 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  131. 131

    Gould, S. T. & Anseth, K. S. Role of cell-matrix interactions on VIC phenotype and tissue deposition in 3D PEG hydrogels. J. Tissue Eng. Regen Med. http://dx.doi.org/10.1002/term.1836.

  132. 132

    Konitsiotis, A. D. et al. Characterization of high affinity binding motifs for the discoidin domain receptor DDR2 in collagen. J. Biol. Chem. 283, 6861–6868 (2008).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  133. 133

    Parenteau-Bareil, R., Gauvin, R. & Berthod, F. Collagen-based biomaterials for tissue engineering applications. Materials 3, 1863–1887 (2010).

    Article  CAS  Google Scholar 

  134. 134

    McCall, J. D., Luoma, J. E. & Anseth, K. S. Covalently tethered transforming growth factor beta in PEG hydrogels promotes chondrogenic differentiation of encapsulated human mesenchymal stem cells. Drug Deliv. Transl. Res. 2, 305–312 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  135. 135

    Lee, K., Silva, E. A. & Mooney, D. J. Growth factor delivery-based tissue engineering: general approaches and a review of recent developments. J. R. Soc. Interface 8, 153–170 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  136. 136

    Lutolf, M. P. et al. Repair of bone defects using synthetic mimetics of collagenous extracellular matrices. Nat. Biotechnol. 21, 513–518 (2003).

    Article  CAS  Google Scholar 

  137. 137

    Wipff, P.-J., Rifkin, D. B., Meister, J.-J. & Hinz, B. Myofibroblast contraction activates latent TGF- beta1 from the extracellular matrix. J. Cell Biol. 179, 1311–1323 (2007).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  138. 138

    Jenkins, G. The role of proteases in transforming growth factor-beta activation. Int. J. Biochem. Cell Biol. 40, 1068–1078 (2008).

    Article  CAS  Google Scholar 

  139. 139

    Lin, C.-C. & Anseth, K. S. Controlling affinity binding with peptide-functionalized poly(ethylene glycol) hydrogels. Adv. Funct. Mater. 19, 2325–2331 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  140. 140

    Callister, W. D. Fundamentals of Materials Science and Engineering: an Interactive E-Text, 5th edn 153–157 (Wiley, 2000).

    Google Scholar 

  141. 141

    Zhao, R., Sider, K. L. & Simmons, C. A. Measurement of layer-specific mechanical properties in multilayered biomaterials by micropipette aspiration. Acta Biomater. 7, 1220–1227 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  142. 142

    Krishnamurthy, V. K., Guilak, F., Narmoneva, D. A. & Hinton, R. B. Regional structure–function relationships in mouse aortic valve tissue. J. Biomech. 44, 77–83 (2011).

    Article  PubMed  PubMed Central  Google Scholar 

  143. 143

    Sewell-Loftin, M. K., Brown, C. B., Baldwin, H. S. & Merryman, W. D. A novel technique for quantifying mouse heart valve leaflet stiffness with atomic force microscopy. J. Heart Valve Dis. 21, 513–520 (2012).

    PubMed  PubMed Central  Google Scholar 

  144. 144

    Stella, J. A. & Sacks, M. S. On the biaxial mechanical properties of the layers of the aortic valve leaflet. J. Biomech. Eng. 129, 757–766 (2007).

    Article  PubMed  PubMed Central  Google Scholar 

  145. 145

    Kloxin, A. M., Benton, J. A. & Anseth, K. S. In situ elasticity modulation with dynamic substrates to direct cell phenotype. Biomaterials 31, 1–8 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  146. 146

    Liu, F. et al. Feedback amplification of fibrosis through matrix stiffening and COX-2 suppression. J. Cell Biol. 190, 693–706 (2010).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  147. 147

    Chen, J.-H., Chen, W. L. K., Sider, K. L., Yip, C. Y. Y. & Simmons, C. A. β-Catenin mediates mechanically regulated, transforming growth factor-β1 induced myofibroblast differentiation of aortic valve interstitial cells. Arterioscler. Thromb. Vasc. Biol. 31, 590–597 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  148. 148

    Olsen, A. L. et al. Hepatic stellate cells require a stiff environment for myofibroblastic differentiation. Am. J. Physiol. Gastrointest. Liver Physiol. 301, G110–G118 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  149. 149

    Wang, H.-B., Dembo, M. & Wang, Y.-L. Substrate flexibility regulates growth and apoptosis of normal but not transformed cells. Am. J. Physiol. Cell. Physiol. 279, C1345–C1350 (2000).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  150. 150

    Zhang, Y.-H., Zhao, C.-Q., Jiang, L.-S. & Dai, L.-Y. Substrate stiffness regulates apoptosis and the mRNA expression of extracellular matrix regulatory genes in the rat annular cells. Matrix Biol. 30, 135–144 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  151. 151

    Kural, M. H. & Billiar, K. L. Mechanoregulation of valvular interstitial cell phenotype in the third dimension. Biomaterials 35, 1128–1137 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  152. 152

    Dupont, S. et al. Role of YAP/TAZ in mechanotransduction. Nature 474, 179–183 (2011).

    Article  CAS  Google Scholar 

  153. 153

    Witt, W., Selle, A., Jannasch, A., Matschke, K. & Waldow, T. Expression of the Hippo effectors YAP and TAZ in valvular interstitial cells from porcine aortic valves. Thorac. Cardiovasc. Surg. 62, SC130 (2014).

    Article  Google Scholar 

  154. 154

    Katsumi, A., Orr, A. W., Tzima, E. & Schwartz, M. A. Integrins in mechanotransduction. J. Biol. Chem. 279, 12001–12004 (2004).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  155. 155

    Trappmann, B. et al. Extracellular-matrix tethering regulates stem-cell fate. Nat. Mater. 11, 642–649 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  156. 156

    Khetan, S. et al. Degradation-mediated cellular traction directs stem cell fate in covalently crosslinked three-dimensional hydrogels. Nat. Mater. 12, 458–465 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  157. 157

    Sacks, M. S. & Yoganathan, A. P. Heart valve function: a biomechanical perspective. Philos. Trans. R. Soc. B Biol. Sci. 362, 1369–1391 (2007).

    Article  Google Scholar 

  158. 158

    Sacks, M. S., Schoen, F. J. & Mayer, J. E. Bioengineering challenges for heart valve tissue engineering. Annu. Rev. Biomed. Eng. 11, 289–313 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  159. 159

    Butcher, J. T., Mahler, G. J. & Hockaday, L. A. Aortic valve disease and treatment: the need for naturally engineered solutions. Adv. Drug Deliv. Rev. 63, 242–268 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  160. 160

    Fan, R. & Sacks, M. S. Simulation of planar soft tissues using a structural constitutive model: Finite element implementation and validation. J. Biomech. 47, 2043–2054 (2014).

    Article  PubMed  PubMed Central  Google Scholar 

  161. 161

    Yap, C. H., Saikrishnan, N., Tamilselvan, G. & Yoganathan, A. P. Experimental technique of measuring dynamic fluid shear stress on the aortic surface of the aortic valve leaflet. J. Biomech. Eng. 133, 061007 (2011).

    Article  PubMed  PubMed Central  Google Scholar 

  162. 162

    Wang, H., Leinwand, L. A. & Anseth, K. S. Roles of transforming growth factor-β1 and OB-cadherin in porcine cardiac valve myofibroblast differentiation. FASEB J. http://dx.doi.org/10.1096/fj.14-254623.

  163. 163

    Hutcheson, J. D. et al. Cadherin-11 regulates cell–cell tension necessary for calcific nodule formation by valvular myofibroblasts. Arterioscler. Thromb. Vasc. Biol. 33, 114–120 (2013).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  164. 164

    Lee, D. M. et al. Cadherin-11 in synovial lining formation and pathology in arthritis. Science 315, 1006–1010 (2007).

    Article  CAS  Google Scholar 

  165. 165

    Schneider, D. J. et al. Cadherin-11 contributes to pulmonary fibrosis: potential role in TGF-beta production and epithelial to mesenchymal transition. FASEB J. 26, 503–512 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  166. 166

    Mahler, G. J., Frendl, C. M., Cao, Q. & Butcher, J. T. Effects of shear stress pattern and magnitude on mesenchymal transformation and invasion of aortic valve endothelial cells. Biotechnol. Bioeng. 4, 25291 (2014).

    Google Scholar 

  167. 167

    Butcher, J. T. & Nerem, R. M. Valvular endothelial cells regulate the phenotype of interstitial cells in co-culture: effects of steady shear stress. Tissue Eng. 12, 905–915 (2006).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  168. 168

    Tseng, H. et al. A three-dimensional co-culture model of the aortic valve using magnetic levitation. Acta Biomater. 10, 173–182 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  169. 169

    Wylie, R. G. et al. Spatially controlled simultaneous patterning of multiple growth factors in three-dimensional hydrogels. Nat. Mater. 10, 799–806 (2011).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  170. 170

    DeForest, C. A. & Anseth, K. S. Photoreversible patterning of biomolecules within click-based hydrogels. Angew. Chem. Int. Ed. Engl. 51, 1816–1819 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  171. 171

    Gandavarapu, N. R., Azagarsamy, M. A. & Anseth, K. S. Photo-click living strategy for controlled, reversible exchange of biochemical ligands. Adv. Mater. 26, 2521–2526 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  172. 172

    Kloxin, A. M., Kasko, A. M., Salinas, C. N. & Anseth, K. S. Photodegradable hydrogels for dynamic tuning of physical and chemical properties. Science 324, 59–63 (2009).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  173. 173

    Kirschner, C. M., Alge, D. L., Gould, S. T. & Anseth, K. S. Clickable, photodegradable hydrogels to dynamically modulate valvular interstitial cell phenotype. Adv. Healthc. Mater. 3, 649–657 (2014).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  174. 174

    Guvendiren, M. & Burdick, J. A. Stiffening hydrogels to probe short- and long-term cellular responses to dynamic mechanics. Nat. Commun. 3, 792 (2012).

    Article  CAS  PubMed  PubMed Central  Google Scholar 

  175. 175

    Guvendiren, M., Perepelyuk, M., Wells, R. G. & Burdick, J. A. Hydrogels with differential and patterned mechanics to study stiffness-mediated myofibroblastic differentiation of hepatic stellate cells. J. Mech. Behav. Biomed. Mater. 4, 00395–00390 (2013).

    Google Scholar 

Download references

Acknowledgements

We acknowledge K. Barthel, P. Harvey, W. Wan, and K. Mabry (University of Colorado, Boulder, CO, USA) for kindly reading and editing the paper, and W. Wan for assistance in taking images for Figure 3. The authors' research work is supported by NIH research grants R01 GM029090 to L.A.L and the Howard Hughes Medical Institute to K.S.A.

Author information

Affiliations

Authors

Contributions

H.W. researched data for the article. All the authors made substantial contribution to discussion of the content, and wrote, reviewed, and edited the manuscript before submission.

Corresponding author

Correspondence to Kristi S. Anseth.

Ethics declarations

Competing interests

The authors declare no competing financial interests.

PowerPoint slides

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Wang, H., Leinwand, L. & Anseth, K. Cardiac valve cells and their microenvironment—insights from in vitro studies. Nat Rev Cardiol 11, 715–727 (2014). https://doi.org/10.1038/nrcardio.2014.162

Download citation

Further reading

Search

Quick links

Nature Briefing

Sign up for the Nature Briefing newsletter — what matters in science, free to your inbox daily.

Get the most important science stories of the day, free in your inbox. Sign up for Nature Briefing