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.

Mechanical strain triggers endothelial-to-mesenchymal transition of the endocardium in the immature heart

Pediatric Research volume 92, pages 721–728 (2022)Cite this article

Abstract

Background

Endothelial-to-mesenchymal-transition (EndMT) plays a major role in cardiac fibrosis, including endocardial fibroelastosis but the stimuli are still unknown. We developed an endothelial cell (EC) culture and a whole heart model to test whether mechanical strain triggers TGF-β-mediated EndMT.

Methods

Isolated ECs were exposed to 10% uniaxial static stretch for 8 h (stretch) and TGF-β-mediated EndMT was determined using the TGF-β-inhibitor SB431542 (stretch + TGF-β-inhibitor), BMP-7 (stretch + BMP-7) or losartan (stretch + losartan), and isolated mature and immature rats were exposed to stretch through a weight on the apex of the left ventricle. Immunohistochemical staining for double-staining with endothelial markers (VE-cadherin, PECAM1) and mesenchymal markers (αSMA) or transcription factors (SLUG/SNAIL) positive nuclei was indicative of EndMT.

Results

Stretch-induced EndMT in ECs expressed as double-stained ECs/total ECs (cells: 46 ± 13%; heart: 15.9 ± 2%) compared to controls (cells: 7 ± 2%; heart: 3.1 ± 0.1; p < 0.05), but only immature hearts showed endocardial EndMT. Inhibition of TGF-β decreased the number of double-stained cells significantly, comparable to controls (cells/heart: control: 7 ± 2%/3.1 ± 0.1%, stretch: 46 ± 13%/15 ± 2%, stretch + BMP-7: 7 ± 2%/2.9 ± 0.1%, stretch + TGF-β-inhibitor (heart only): 5.2 ± 1.3%, stretch + losartan (heart only): 0.89 ± 0.1%; p < 0.001 versus stretch).

Conclusions

Endocardial EndMT is an age-dependent consequence of increased strain triggered by TGF- β activation. Local inhibition through either rebalancing TGF-β/BMP or with losartan was effective to block EndMT.

Impact

  • Mechanical strain imposed on the immature LV induces endocardial fibroelastosis (EFE) formation through TGF-β-mediated activation of endothelial-to-mesenchymal transition (EndMT) in endocardial endothelial cells but has no effect in mature hearts.

  • Local inhibition through either rebalancing the TGF-β/BMP pathway or with losartan blocks EndMT.

  • Inhibition of endocardial EndMT with clinically applicable treatments may lead to a better outcome for congenital heart defects associated with EFE.

This is a preview of subscription content, access via your institution

Access options

Rent or buy this article

Get just this article for as long as you need it

$39.95

Learn more

Prices may be subject to local taxes which are calculated during checkout

Fig. 1: Static stretch triggers EndMT in isolated endothelial cells.
Fig. 2: Stretch-induced EndMT is mediated through activation of the TGF-β pathway.
Fig. 3: Excess strain induces EndMT in immature hearts.
Fig. 4: Excess strain does not induce EndMT in mature hearts.
Fig. 5: EndMT-regulating transcription factors (SLUG/SNAIL) in immature versus mature hearts.

Data availability

The original data set used and analyzed during the current study is readily available from the corresponding author on reasonable request.

References

  1. Sumpio, B. E., Riley, J. T. & Dardik, A. Cells in focus: endothelial cell. Int J. Biochem. Cell Biol. 34, 1508–1512 (2002).

    Article  CAS  Google Scholar 

  2. Traub, O. & Berk, B. C. Laminar shear stress: mechanisms by which endothelial cells transduce an atheroprotective force. Arterioscler. Thromb. Vasc. Biol. 8, 677–685 (1998).

    Article  Google Scholar 

  3. Zeisberg, E. M. et al. Endothelial-to-mesenchymal transition contributes to cardiac fibrosis. Nat. Med. 13, 952–961 (2007).

    Article  CAS  Google Scholar 

  4. Arciniegas, E. et al. Endothelial-mesenchymal transition occurs during embryonic pulmonary artery development. Endothelium 12, 193–200 (2005).

    Article  CAS  Google Scholar 

  5. Zeisberg, E. M. et al. Fibroblasts in kidney fibrosis emerge via endothelial-to-mesenchymal transition. J. Am. Soc. Nephrol. 19, 2282–2287 (2008).

    Article  Google Scholar 

  6. Xu, X. et al. Endocardial fibroelastosis is caused by aberrant endothelial to mesenchymal transition. Circ. Res. 116, 857–866 (2015).

    Article  CAS  Google Scholar 

  7. Pusztaszeri, M. P., Seelentag, W. & Bosman, F. T. Immunohistochemical expression of endothelial markers CD31, CD34, von Willebrand Factor, and Fli-1 in normal human tissues. J. Histochem. Cytochem. 54, 385–395 (2006).

    Article  CAS  Google Scholar 

  8. Yoshimatsu, Y. & Watabe, T. Roles of TGF-β signals in endothelial-mesenchymal transition during cardiac fibrosis. Int. J. Inflam. 2011, 724080 (2011).

    PubMed  PubMed Central  Google Scholar 

  9. Illigens, B. M. W. et al. Vascular endothelial growth factor prevents endothelial-to-mesenchymal transition in hypertrophy. Ann. Thorac. Surg. 104, 932–939 (2017).

    Article  Google Scholar 

  10. Weixler, V. et al. Flow disturbances and the development of endocardial fibroelastosis. J. Thorac. Cardiovasc. Surg. 159, 637–646 (2020).

    Article  CAS  Google Scholar 

  11. Emani, S. M. et al. Staged left ventricular recruitment after single-ventricle palliation in patients with borderline left heart hypoplasia. J. Am. Coll. Cardiol. 60, 1966–1974 (2012).

    Article  Google Scholar 

  12. McElhinney, D. B. et al. Assessment of left ventricular endocardial fibroelastosis in fetuses with aortic stenosis and evolving hypoplastic left heart syndrome. Am J Cardiol. 106, 1792–1797 (2010).

    Article  Google Scholar 

  13. Friehs, I. et al. Impaired glucose transporter activity in pressure-overload hypertrophy is an early indicator of progression to failure. Circulation 100, II187–II193 (1999).

    Article  CAS  Google Scholar 

  14. Friehs, I. et al. Promoting angiogenesis protects severely hypertrophied hearts from ischemic injury. Ann. Thorac. Surg. 77, 2004–2010 (2004).

    Article  Google Scholar 

  15. Kalluri, R. & Zeisberg, M. Fibroblasts in cancer. Nat. Rev. Cancer 6, 392–401 (2006).

    Article  CAS  Google Scholar 

  16. Suzuki, M. et al. Up-regulation of integrin β3 expression by cyclic stretch in human umbilical endothelial cells. Biochem. Biophys. Res. Commun. 239, 372–376 (1997).

    Article  CAS  Google Scholar 

  17. Rieder, F. et al. Inflammation-induced endothelial-to-mesenchymal transition: a novel mechanism of intestinal fibrosis. Am. J. Pathol. 179, 2660–2673 (2011).

    Article  CAS  Google Scholar 

  18. Wu, B. et al. Endocardial cells form the coronary arteries by angiogenesis through myocardial-endocardial VEGF signaling. Cell 151, 1083–1096 (2012).

    Article  CAS  Google Scholar 

  19. Kong, P. et al. Lack of specificity of fibroblast-specific protein 1 in cardiac remodeling and fibrosis. Am. J. Physiol. 305, H1363–H1372 (2013).

    CAS  Google Scholar 

  20. Shimada, S. et al. Distention of the immature left ventricle triggers development of endocardial fibroelastosis: An animal model of endocardial fibroelastosis introducing morphopathological features of evolving fetal hypoplastic left heart syndrome. Biomed. Res. Int. 2015, 46469 (2015).

    Article  Google Scholar 

  21. Lopez, D. et al. Tumor-induced upregulation of Twist, Snail, and Slug represses the activity of the human VE-cadherin promoter. Arch. Biochem. Biophys. 482, 77–82 (2009).

    Article  CAS  Google Scholar 

  22. Watabe, T. et al. TGF-β receptor kinase inhibitor enhances growth and integrity of embryonic stem cell–derived endothelial cells. J. Cell Biol. 163, 1303–1311 (2003).

    Article  CAS  Google Scholar 

  23. Wu, M. et al. Losartan attenuates myocardial endothelial-to-mesenchymal transition in spontaneous hypertensive rats via inhibiting TGF-β/Smad signaling. PLoS ONE 11, e0155730 (2016).

    Article  Google Scholar 

Download references

Acknowledgements

This research did not receive any specific grant from funding agencies in the public commercial or not-for-profit sectors but was supported by discretionary departmental funds.

Author information

Author notes

  1. These authors contributed equally: Carina Vorisek, Viktoria Weixler.

Authors and Affiliations

  1. Department of Cardiac Surgery, Boston Children’s Hospital and Harvard Medical School, Boston, MA, USA

    Carina Vorisek, Viktoria Weixler, Massiel Dominguez, Peter E. Hammer, Ruei-Zeng Lin, Juan M. Melero-Martin, Pedro J. del Nido & Ingeborg Friehs

  2. Center for Prenatal Medicine and Fetal Therapy, Justus-Liebig-University of Giessen, Giessen, Germany

    Roland Axt-Fliedner

Authors
  1. Carina Vorisek
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Viktoria Weixler
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Massiel Dominguez
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Roland Axt-Fliedner
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. Peter E. Hammer
    View author publications

    You can also search for this author in PubMed Google Scholar

  6. Ruei-Zeng Lin
    View author publications

    You can also search for this author in PubMed Google Scholar

  7. Juan M. Melero-Martin
    View author publications

    You can also search for this author in PubMed Google Scholar

  8. Pedro J. del Nido
    View author publications

    You can also search for this author in PubMed Google Scholar

  9. Ingeborg Friehs
    View author publications

    You can also search for this author in PubMed Google Scholar

Contributions

C.V., V.W., and I.F. provided substantial contributions to conception and design, C.V., V.W., M.D., P.H., R.-Z.L., and I.F. contributed to the acquisition and analysis of data. C.V., V.W., M.D., P.H., J.M.M.-M., R.A.-F., P.J.d.N., and I.F. were involved in the interpretation of data. C.V., V.W., and I.F. drafted the article, and R.A.-F., P.H., R.-Z.L., J.M.M.-M., and P.J.d.N. commented for revision of the manuscript. All authors granted final approval of the version to be published.

Corresponding author

Correspondence to Ingeborg Friehs.

Ethics declarations

Competing interests

The authors declare no competing interests.

Additional information

Publisher’s note Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.

Rights and permissions

Reprints and Permissions

About this article

Verify currency and authenticity via CrossMark

Cite this article

Vorisek, C., Weixler, V., Dominguez, M. et al. Mechanical strain triggers endothelial-to-mesenchymal transition of the endocardium in the immature heart. Pediatr Res 92, 721–728 (2022). https://doi.org/10.1038/s41390-021-01843-6

Download citation

  • Received:

  • Revised:

  • Accepted:

  • Published:

  • Issue Date:

  • DOI: https://doi.org/10.1038/s41390-021-01843-6

Search

Advanced search

Quick links