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Unraveling the mechanism of cell death induced by chemical fibrils

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Abstract

We previously discovered a small-molecule inducer of cell death, named 1541, that noncovalently self-assembles into chemical fibrils ('chemi-fibrils') and activates procaspase-3 in vitro. We report here that 1541-induced cell death is caused by the fibrillar rather than the soluble form of the drug. A short hairpin RNA screen reveals that knockdown of genes involved in endocytosis, vesicle trafficking and lysosomal acidification causes partial 1541 resistance. We confirm the role of these pathways using pharmacological inhibitors. Microscopy shows that the fluorescent chemi-fibrils accumulate in punctae inside cells that partially colocalize with lysosomes. Notably, the chemi-fibrils bind and induce liposome leakage in vitro, suggesting they may do the same in cells. The chemi-fibrils induce extensive proteolysis including caspase substrates, yet modulatory profiling reveals that chemi-fibrils form a distinct class from existing inducers of cell death. The chemi-fibrils share similarities with proteinaceous fibrils and may provide insight into their mechanism of cellular toxicity.

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Figure 1: 1541 forms chemi-fibrils that induce cell death in cell culture.
Figure 2: shRNA screen reveals a major role of vesicle trafficking and lysosome acidification in 1541 chemi-fibril–induced cell death.
Figure 3: Internalization of fluorescent aggregates in cell and specific endocytosis inhibition delay cell death.
Figure 4: Cell death induced by chemi-fibrils induces proteolysis with prominent caspase cleavages.
Figure 5: Modulatory profiling suggests 1541 and an analog form a unique class of compounds that induce cell death only partially delayed by blocking caspases.
Figure 6: Proposed mechanism of cell death induced by 1541 chemi-fibrils.

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References

  1. Jucker, M. & Walker, L.C. Self-propagation of pathogenic protein aggregates in neurodegenerative diseases. Nature 501, 45–51 (2013).

    Article  CAS  Google Scholar 

  2. Eisenberg, D. & Jucker, M. The amyloid state of proteins in human diseases. Cell 148, 1188–1203 (2012).

    Article  CAS  Google Scholar 

  3. Wolan, D.W., Zorn, J.A., Gray, D.C. & Wells, J.A. Small-molecule activators of a proenzyme. Science 326, 853–858 (2009).

    Article  CAS  Google Scholar 

  4. Zorn, J.A., Wille, H., Wolan, D.W. & Wells, J.A. Self-assembling small molecules form nanofibrils that bind procaspase-3 to promote activation. J. Am. Chem. Soc. 133, 19630–19633 (2011).

    Article  CAS  Google Scholar 

  5. Zorn, J.A., Wolan, D.W., Agard, N.J. & Wells, J.A. Fibrils colocalize caspase-3 with procaspase-3 to foster maturation. J. Biol. Chem. 287, 33781–33795 (2012).

    Article  CAS  Google Scholar 

  6. Bassik, M.C. et al. Rapid creation and quantitative monitoring of high coverage shRNA libraries. Nat. Methods 6, 443–445 (2009).

    Article  CAS  Google Scholar 

  7. Bassik, M.C. et al. A systematic Mammalian genetic interaction map reveals pathways underlying ricin susceptibility. Cell 152, 909–922 (2013).

    Article  CAS  Google Scholar 

  8. Kampmann, M., Bassik, M.C. & Weissman, J.S. Integrated platform for genome-wide screening and construction of high-density genetic interaction maps in mammalian cells. Proc. Natl. Acad. Sci. USA 110, E2317–E2326 (2013).

    Article  CAS  Google Scholar 

  9. Weiss, W.A., Taylor, S.S. & Shokat, K.M. Recognizing and exploiting differences between RNAi and small-molecule inhibitors. Nat. Chem. Biol. 3, 739–744 (2007).

    Article  CAS  Google Scholar 

  10. Crawford, E.D. et al. The DegraBase: a database of proteolysis in healthy and apoptotic human cells. Mol. Cell. Proteomics 12, 813–824 (2013).

    Article  CAS  Google Scholar 

  11. Mahrus, S. et al. Global sequencing of proteolytic cleavage sites in apoptosis by specific labeling of protein N termini. Cell 134, 866–876 (2008).

    Article  CAS  Google Scholar 

  12. Wiita, A.P., Seaman, J.E. & Wells, J.A. Global analysis of cellular proteolysis by selective enzymatic labeling of protein N-termini. Methods Enzymol. 544, 327–358 (2014).

    Article  CAS  Google Scholar 

  13. Wolpaw, A.J. et al. Modulatory profiling identifies mechanisms of small molecule–induced cell death. Proc. Natl. Acad. Sci. USA 108, E771–E780 (2011).

    Article  CAS  Google Scholar 

  14. Holmes, B.B. et al. Heparan sulfate proteoglycans mediate internalization and propagation of specific proteopathic seeds. Proc. Natl. Acad. Sci. USA 110, E3138–E3147 (2013).

    Article  CAS  Google Scholar 

  15. Owen, S.C., Doak, A.K., Wassam, P., Shoichet, M.S. & Shoichet, B.K. Colloidal aggregation affects the efficacy of anticancer drugs in cell culture. ACS Chem. Biol. 7, 1429–1435 (2012).

    Article  CAS  Google Scholar 

  16. Owen, S.C. et al. Colloidal drug formulations can explain “bell-shaped” concentration-response curves. ACS Chem. Biol. 9, 777–784 (2014).

    Article  CAS  Google Scholar 

  17. Kampmann, M., Bassik, M.C. & Weissman, J.S. Functional genomics platform for pooled screening and generation of mammalian genetic interaction maps. Nat. Protoc. 9, 1825–1847 (2014).

    Article  CAS  Google Scholar 

  18. Tisdale, E.J., Bourne, J.R., Khosravi-Far, R., Der, C.J. & Balch, W.E. GTP-binding mutants of rab1 and rab2 are potent inhibitors of vesicular transport from the endoplasmic reticulum to the Golgi complex. J. Cell Biol. 119, 749–761 (1992).

    Article  CAS  Google Scholar 

  19. Bucci, C., Thomsen, P., Nicoziani, P., McCarthy, J. & van Deurs, B. Rab7: a key to lysosome biogenesis. Mol. Biol. Cell 11, 467–480 (2000).

    Article  CAS  Google Scholar 

  20. Stenmark, H., Vitale, G., Ullrich, O. & Zerial, M. Rabaptin-5 is a direct effector of the small GTPase Rab5 in endocytic membrane fusion. Cell 83, 423–432 (1995).

    Article  CAS  Google Scholar 

  21. Seto, S., Tsujimura, K. & Koide, Y. Rab GTPases regulating phagosome maturation are differentially recruited to mycobacterial phagosomes. Traffic 12, 407–420 (2011).

    Article  CAS  Google Scholar 

  22. Stenmark, H. Rab GTPases as coordinators of vesicle traffic. Nat. Rev. Mol. Cell Biol. 10, 513–525 (2009).

    Article  CAS  Google Scholar 

  23. Münch, C., O'Brien, J. & Bertolotti, A. Prion-like propagation of mutant superoxide dismutase-1 misfolding in neuronal cells. Proc. Natl. Acad. Sci. USA 108, 3548–3553 (2011).

    Article  Google Scholar 

  24. Weinstein, J.N., Yoshikami, S., Henkart, P., Blumenthal, R. & Hagins, W.A. Liposome-cell interaction: transfer and intracellular release of a trapped fluorescent marker. Science 195, 489–492 (1977).

    Article  CAS  Google Scholar 

  25. Shimbo, K. et al. Quantitative profiling of caspase-cleaved substrates reveals different drug-induced and cell-type patterns in apoptosis. Proc. Natl. Acad. Sci. USA 109, 12432–12437 (2012).

    Article  CAS  Google Scholar 

  26. Wiita, A.P. et al. Global cellular response to chemotherapy-induced apoptosis. Elife 2, e01236 (2013).

    Article  Google Scholar 

  27. Fraley, C. & Raftery, A.E. Model-based clustering, discriminant analysis, and density estimation. J. Am. Stat. Assoc. 97, 611–631 (2002).

    Article  Google Scholar 

  28. Duewell, P. et al. NLRP3 inflammasomes are required for atherogenesis and activated by cholesterol crystals. Nature 464, 1357–1361 (2010).

    Article  CAS  Google Scholar 

  29. Halle, A. et al. The NALP3 inflammasome is involved in the innate immune response to amyloid-β. Nat. Immunol. 9, 857–865 (2008).

    Article  CAS  Google Scholar 

  30. Huff, M.E., Balch, W.E. & Kelly, J.W. Pathological and functional amyloid formation orchestrated by the secretory pathway. Curr. Opin. Struct. Biol. 13, 674–682 (2003).

    Article  CAS  Google Scholar 

  31. Novitskaya, V., Bocharova, O.V., Bronstein, I. & Baskakov, I.V. Amyloid fibrils of mammalian prion protein are highly toxic to cultured cells and primary neurons. J. Biol. Chem. 281, 13828–13836 (2006).

    Article  CAS  Google Scholar 

  32. Yao, J. et al. Neuroprotection by cyclodextrin in cell and mouse models of Alzheimer disease. J. Exp. Med. 209, 2501–2513 (2012).

    Article  CAS  Google Scholar 

  33. Walsh, D.M. & Selkoe, D.J. Aβ oligomers—a decade of discovery. J. Neurochem. 101, 1172–1184 (2007).

    Article  CAS  Google Scholar 

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Acknowledgements

We would like to thank F. Brodsky, B. Shoichet, W. Degrado, M. Zhuang, A. Wiita, Z. Hill, J.T. Koerber, N. Thomsen, J. Watts, S.-A. Mok and J. Rettenmaier for insightful discussions and/or critical reading of the manuscript. A special thanks to Y. Chen (cell culture and laboratory practices expertise), Y. Cheng and M. Braunfield (EM), A. Doak (DLS), H. Tran (yeast expertise), D. Larsen (live cell imaging), J. Lund (deep sequencing), M. Hornsby and K. Verba (fluorescence) and T. Matsuguchi (qPCR) for technical help. This work was supported, in whole or in part, by US National Institutes of Health grant R01 CA136779 (to J.A.W.), R01 CA097061 (to B.R.S.) and F32AI095062 (to V.J.V.) and by the Howard Hughes Medical Institute (to B.R.S. and J.S.W.). J.A.Z. received an Achievement Rewards for College Scientists Foundation Award and a Schleroderma Research Foundation Evnin-Wright Fellowship. M.K. was supported by a postdoctoral fellowship from the Jane Coffin Childs Memorial Fund. O.J. is the recipient of a Banting Postdoctoral Fellowship funded by the Canadian Institutes of Health Research and the Government of Canada. O.J. and M.K. both received a fellowship from the University of California–San Francisco Program for Breakthrough Biomedical Research, which is funded in part by the Sandler Foundation.

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Contributions

O.J. performed the cell culture experiments, EM, DLS, flow cytometry and fluorescence microscopy under J.A.W.'s supervision. O.J. performed the shRNA screen and made the stable cell lines, with help and guidance from M.K. and M.C.B. and supervision of J.S.W.; M.K. analyzed the deep-sequencing data. J.A.Z. synthesized the 1541 analogs and provided general expertise on the project. A.L.R. performed the crystallography and structure determination. V.J.V. performed the liposome leakage assays. K. Shimbo and N.J.A. performed the degradomics experiments, and O.J. compiled the results. K. Shimada performed the modulatory profiling experiments under B.R.S.'s supervision. O.J. and J.A.W. wrote the manuscript with contributions from M.K., J.A.Z. and B.R.S., with input from all authors.

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Correspondence to James A Wells.

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Supplementary information

Supplementary Text and Figures

Supplementary Results and Supplementary Figures 1–22. (PDF 12319 kb)

Supplementary Data Set 1

P values for all genes tested in the shRNA screen. (XLSX 324 kb)

Supplementary Data Set 2

Identification of proteolytic fragments generated during chemi-fibril induced cell death. (XLSX 3535 kb)

Supplementary Video 1

Live cell imaging of HeLa cells treated with chemi-fibrils. (MOV 5773 kb)

Supplementary Video 2

Live cell imaging of HeLa cells treated with chemi-fibrils. (MOV 13992 kb)

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Julien, O., Kampmann, M., Bassik, M. et al. Unraveling the mechanism of cell death induced by chemical fibrils. Nat Chem Biol 10, 969–976 (2014). https://doi.org/10.1038/nchembio.1639

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