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The role of autophagy in cardiomyocytes in the basal state and in response to hemodynamic stress

Abstract

Autophagy, an evolutionarily conserved process for the bulk degradation of cytoplasmic components, serves as a cell survival mechanism in starving cells1,2. Although altered autophagy has been observed in various heart diseases, including cardiac hypertrophy3,4 and heart failure5,6, it remains unclear whether autophagy plays a beneficial or detrimental role in the heart. Here, we report that the cardiac-specific loss of autophagy causes cardiomyopathy in mice. In adult mice, temporally controlled cardiac-specific deficiency of Atg5 (autophagy-related 5), a protein required for autophagy, led to cardiac hypertrophy, left ventricular dilatation and contractile dysfunction, accompanied by increased levels of ubiquitination. Furthermore, Atg5-deficient hearts showed disorganized sarcomere structure and mitochondrial misalignment and aggregation. On the other hand, cardiac-specific deficiency of Atg5 early in cardiogenesis showed no such cardiac phenotypes under baseline conditions, but developed cardiac dysfunction and left ventricular dilatation one week after treatment with pressure overload. These results indicate that constitutive autophagy in the heart under baseline conditions is a homeostatic mechanism for maintaining cardiomyocyte size and global cardiac structure and function, and that upregulation of autophagy in failing hearts is an adaptive response for protecting cells from hemodynamic stress.

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Figure 1: Cardiac dysfunction in tamoxifen-treated Atg5flox/flox;MerCreMer+ mice.
Figure 2: Hypertrophic responses in tamoxifen-treated Atg5flox/flox;MerCreMer+ mice.
Figure 3: Biochemical and histological abnormalities in tamoxifen-treated Atg5flox/flox;MerCreMer+ mice.
Figure 4: Pressure overload induces cardiac dysfunction in Atg5flox/flox;MLC2v-Cre+ mice.

References

  1. Mizushima, N., Ohsumi, Y. & Yoshimori, T. Autophagosome formation in mammalian cells. Cell Struct. Funct. 27, 421–429 (2002).

    Article  Google Scholar 

  2. Levine, B. & Klionsky, D.J. Development by self-digestion: molecular mechanisms and biological functions of autophagy. Dev. Cell 6, 463–477 (2004).

    CAS  Article  Google Scholar 

  3. Dammrich, J. & Pfeifer, U. Cardiac hypertrophy in rats after supravalvular aortic constriction. II. Inhibition of cellular autophagy in hypertrophying cardiomyocytes. Virchows Arch. B Cell Pathol. Incl. Mol. Pathol. 43, 287–307 (1983).

    CAS  Article  Google Scholar 

  4. Pfeifer, U., Fohr, J., Wilhelm, W. & Dammrich, J. Short-term inhibition of cardiac cellular autophagy by isoproterenol. J. Mol. Cell. Cardiol. 19, 1179–1184 (1987).

    CAS  Article  Google Scholar 

  5. Shimomura, H. et al. Autophagic degeneration as a possible mechanism of myocardial cell death in dilated cardiomyopathy. Jpn. Circ. J. 65, 965–968 (2001).

    CAS  Article  Google Scholar 

  6. Miyata, S. et al. Autophagic cardiomyocyte death in cardiomyopathic hamsters and its prevention by granulocyte colony-stimulating factor. Am. J. Pathol. 168, 386–397 (2006).

    CAS  Article  Google Scholar 

  7. Kuma, A. et al. The role of autophagy during the early neonatal starvation period. Nature 432, 1032–1036 (2004).

    CAS  Article  Google Scholar 

  8. Komatsu, M. et al. Impairment of starvation-induced and constitutive autophagy in Atg7-deficient mice. J. Cell Biol. 169, 425–434 (2005).

    CAS  Article  Google Scholar 

  9. Hara, T. et al. Suppression of basal autophagy in neural cells causes neurodegenerative disease in mice. Nature 441, 885–889 (2006).

    CAS  Article  Google Scholar 

  10. Komatsu, M. et al. Loss of autophagy in the central nervous system causes neurodegeneration in mice. Nature 441, 880–884 (2006).

    CAS  Article  Google Scholar 

  11. Baehrecke, E.H. Autophagy: dual roles in life and death? Nat. Rev. Mol. Cell Biol. 6, 505–510 (2005).

    CAS  Article  Google Scholar 

  12. Decker, R.S. & Wildenthal, K. Lysosomal alterations in hypoxic and reoxygenated hearts. I. Ultrastructural and cytochemical changes. Am. J. Pathol. 98, 425–444 (1980).

    CAS  PubMed  PubMed Central  Google Scholar 

  13. Yan, L. et al. Autophagy in chronically ischemic myocardium. Proc. Natl. Acad. Sci. USA 102, 13807–13812 (2005).

    CAS  Article  Google Scholar 

  14. Nishino, I. et al. Primary LAMP-2 deficiency causes X-linked vacuolar cardiomyopathy and myopathy (Danon disease). Nature 406, 906–910 (2000).

    CAS  Article  Google Scholar 

  15. Tanaka, Y. et al. Accumulation of autophagic vacuoles and cardiomyopathy in LAMP-2-deficient mice. Nature 406, 902–906 (2000).

    CAS  Article  Google Scholar 

  16. Sohal, D.S. et al. Temporally regulated and tissue-specific gene manipulations in the adult and embryonic heart using a tamoxifen-inducible Cre protein. Circ. Res. 89, 20–25 (2001).

    CAS  Article  Google Scholar 

  17. Kabeya, Y. et al. LC3, a mammalian homologue of yeast Apg8p, is localized in autophagosome membranes after processing. EMBO J. 19, 5720–5728 (2000).

    CAS  Article  Google Scholar 

  18. Mizushima, N., Yamamoto, A., Matsui, M., Yoshimori, T. & Ohsumi, Y. In vivo analysis of autophagy in response to nutrient starvation using transgenic mice expressing a fluorescent autophagosome marker. Mol. Biol. Cell 15, 1101–1111 (2004).

    CAS  Article  Google Scholar 

  19. Bjorkoy, G. et al. p62/SQSTM1 forms protein aggregates degraded by autophagy and has a protective effect on huntingtin-induced cell death. J. Cell Biol. 171, 603–614 (2005).

    Article  Google Scholar 

  20. Hosokawa, N., Hara, Y. & Mizushima, N. Generation of cell lines with tetracycline-regulated autophagy and a role for autophagy in controlling cell size. FEBS Lett. 580, 2623–2629 (2006).

    CAS  Article  Google Scholar 

  21. Nakagawa, T. et al. Caspase-12 mediates endoplasmic-reticulum-specific apoptosis and cytotoxicity by amyloid-beta. Nature 403, 98–103 (2000).

    CAS  Article  Google Scholar 

  22. Boya, P. et al. Inhibition of macroautophagy triggers apoptosis. Mol. Cell. Biol. 25, 1025–1040 (2005).

    CAS  Article  Google Scholar 

  23. Chen, J. et al. Selective requirement of myosin light chain 2v in embryonic heart function. J. Biol. Chem. 273, 1252–1256 (1998).

    CAS  Article  Google Scholar 

  24. Yamaguchi, O. et al. Cardiac-specific disruption of the c-raf-1 gene induces cardiac dysfunction and apoptosis. J. Clin. Invest. 114, 937–943 (2004).

    CAS  Article  Google Scholar 

  25. Lyons, G.E. et al. Developmental regulation of myosin gene expression in mouse cardiac muscle. J. Cell Biol. 111, 2427–2436 (1990).

    CAS  Article  Google Scholar 

  26. Yamaguchi, O. et al. Targeted deletion of apoptosis signal-regulating kinase 1 attenuates left ventricular remodeling. Proc. Natl. Acad. Sci. USA 100, 15883–15888 (2003).

    CAS  Article  Google Scholar 

  27. Wencker, D. et al. A mechanistic role for cardiac myocyte apoptosis in heart failure. J. Clin. Invest. 111, 1497–1504 (2003).

    CAS  Article  Google Scholar 

  28. Hirotani, S. et al. Involvement of nuclear factor-κB and apoptosis signal-regulating kinase 1 in G-protein-coupled receptor agonist-induced cardiomyocyte hypertrophy. Circulation 105, 509–515 (2002).

    CAS  Article  Google Scholar 

  29. Zhou, Y.Y. et al. Culture and adenoviral infection of adult mouse cardiac myocytes: methods for cellular genetic physiology. Am. J. Physiol. Heart Circ. Physiol. 279, H429–H436 (2000).

    CAS  Article  Google Scholar 

  30. Mizushima, N. et al. Dissection of autophagosome formation using Apg5-deficient mouse embryonic stem cells. J. Cell Biol. 152, 657–668 (2001).

    CAS  Article  Google Scholar 

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Acknowledgements

We are grateful to K. Chien (Harvard University) for the gift of MLC-2v Cre mice, J. Molkentin (Cincinnati Children's Hospital Medical Center) for MerCreMer mice, T. Yoshimori (Osaka University) for antibody to LC3 and E. Lakatta for teaching us to isolate adult mouse cardiomyocytes. This work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology to K.O. (16590683). O.Y. held a postdoctoral fellowship from the Japan Society for the Promotion of Science. S.H. was the recipient of a postdoctoral fellowship from the Center of Excellence Research of the Ministry of Education, Culture, Sports, Science and Technology. T.T. received a postdoctoral fellowship from the Japan Health Science Foundation.

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Authors and Affiliations

Authors

Contributions

A.N. worked on the in vitro analysis of the mice; O.Y. conducted the in vivo analysis of the mice and wrote the manuscript; T.T. performed adult cardiomyocyte isolation and Ca2+ transient experiments; Y.H. performed ischemia-reperfusion surgery; S.H. assisted with RT-PCR experiments; M.T., S.O. and I.M. contributed to the in vitro experiments; Y.M. performed statistical analysis of the data; M.A. contributed to Ca2+ transient measurements; K.N. contributed to the in vivo experiments; M.H. supervised this project; N.M. provided advice on designing and conducting experiments; K.O. conceived, designed and directed the study.

Corresponding author

Correspondence to Kinya Otsu.

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Competing interests

The authors declare no competing financial interests.

Supplementary information

Supplementary Fig. 1

Inhibition of autophagy using adenovirus expressing shRNA against Atg7. (PDF 617 kb)

Supplementary Fig. 2

Characterization of Atg5flox/flox; MLC2v-Cre+ mice. (PDF 235 kb)

Supplementary Fig. 3

Pressure overload induces cardiac dysfunction in Atg5flox/flox; α-MyHC-Cre+ mice. (PDF 372 kb)

Supplementary Fig. 4

Autophagy in pressure overload-induced cardiac remodeling. (PDF 236 kb)

Supplementary Fig. 5

Biochemical analysis of Atg5flox/flox; MLC2v-Cre+ hearts after TAC. (PDF 287 kb)

Supplementary Fig. 6

β-adrenergic stress induces cardiac dysfunction in Atg5flox/flox; MLC2v-Cre+ mice. (PDF 627 kb)

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Nakai, A., Yamaguchi, O., Takeda, T. et al. The role of autophagy in cardiomyocytes in the basal state and in response to hemodynamic stress. Nat Med 13, 619–624 (2007). https://doi.org/10.1038/nm1574

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