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Merlin isoform 2 in neurofibromatosis type 2–associated polyneuropathy

Abstract

The autosomal dominant disorder neurofibromatosis type 2 (NF2) is a hereditary tumor syndrome caused by inactivation of the NF2 tumor suppressor gene, encoding merlin. Apart from tumors affecting the peripheral and central nervous systems, most NF2 patients develop peripheral neuropathies. This peripheral nerve disease can occur in the absence of nerve-damaging tumors, suggesting an etiology that is independent of gross tumor burden. We discovered that merlin isoform 2 (merlin-iso2) has a specific function in maintaining axonal integrity and propose that reduced axonal NF2 gene dosage leads to NF2-associated polyneuropathy. We identified a merlin-iso2–dependent complex that promotes activation of the GTPase RhoA, enabling downstream Rho-associated kinase to promote neurofilament heavy chain phosphorylation. Merlin-iso2–deficient mice exhibited impaired locomotor capacities, delayed sensory reactions and electrophysiological signs of axonal neuropathy. Sciatic nerves from these mice and sural nerve biopsies from NF2 patients revealed reduced phosphorylation of the neurofilament H subunit, decreased interfilament spacings and irregularly shaped axons.

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Figure 1: Merlin-iso2 expressed in axons, mediates neurofilament phosphorylation and axonal radial growth.
Figure 2: Merlin mediates neurofilament phosphorylation via the Rho-ROCK pathway.
Figure 3: Merlin assembles a multi-protein complex relevant for Rho activation.
Figure 4: Axon structure abnormalities in Nf2-iso2−/− mice.
Figure 5: Reduced interfilament distances in Nf2-iso2−/− mice.
Figure 6: Behavioral abnormalities in Nf2-iso2−/− mice.
Figure 7: NF2 patient biopsies display neurofilament hypophosphorylation.

References

  1. Luo, L. Rho GTPases in neuronal morphogenesis. Nat. Rev. Neurosci. 1, 173–180 (2000).

    Article  CAS  Google Scholar 

  2. Perrot, R., Berges, R., Bocquet, A. & Eyer, J. Review of the multiple aspects of neurofilament functions, and their possible contribution to neurodegeneration. Mol. Neurobiol. 38, 27–65 (2008).

    Article  CAS  Google Scholar 

  3. Zhu, Q., Couillard–Despres, S. & Julien, J.P. Delayed maturation of regenerating myelinated axons in mice lacking neurofilaments. Exp. Neurol. 148, 299–316 (1997).

    Article  CAS  Google Scholar 

  4. de Waegh, S.M., Lee, V.M. & Brady, S.T. Local modulation of neurofilament phosphorylation, axonal caliber and slow axonal transport by myelinating Schwann cells. Cell 68, 451–463 (1992).

    Article  CAS  Google Scholar 

  5. Dubois, M., Strazielle, C., Julien, J.P. & Lalonde, R. Mice with the deleted neurofilament of low molecular weight (Nefl) gene. 2. Effects on motor functions and spatial orientation. J. Neurosci. Res. 80, 751–758 (2005).

    Article  CAS  Google Scholar 

  6. England, J.D. & Asbury, A.K. Peripheral neuropathy. Lancet 363, 2151–2161 (2004).

    Article  Google Scholar 

  7. Asthagiri, A.R. et al. Neurofibromatosis type 2. Lancet 373, 1974–1986 (2009).

    Article  CAS  Google Scholar 

  8. Sperfeld, A.D., Hein, C., Schroder, J.M., Ludolph, A.C. & Hanemann, C.O. Occurrence and characterization of peripheral nerve involvement in neurofibromatosis type 2. Brain 125, 996–1004 (2002).

    Article  CAS  Google Scholar 

  9. Schulz, A. et al. Merlin inhibits neurite outgrowth in the CNS. J. Neurosci. 30, 10177–10186 (2010).

    Article  CAS  Google Scholar 

  10. Gianola, S. & Rossi, F. Evolution of the Purkinje cell response to injury and regenerative potential during postnatal development of the rat cerebellum. J. Comp. Neurol. 430, 101–117 (2001).

    Article  CAS  Google Scholar 

  11. Jones–Villeneuve, E.M., McBurney, M.W., Rogers, K.A. & Kalnins, V.I. Retinoic acid induces embryonal carcinoma cells to differentiate into neurons and glial cells. J. Cell Biol. 94, 253–262 (1982).

    Article  Google Scholar 

  12. Hashimoto, R. et al. Domain- and site-specific phosphorylation of bovine NF-L by Rho-associated kinase. Biochem. Biophys. Res. Commun. 245, 407–411 (1998).

    Article  CAS  Google Scholar 

  13. Moorman, J.P., Luu, D., Wickham, J., Bobak, D.A. & Hahn, C.S. A balance of signaling by Rho family small GTPases RhoA, Rac1 and Cdc42 coordinates cytoskeletal morphology, but not cell survival. Oncogene 18, 47–57 (1999).

    Article  CAS  Google Scholar 

  14. Maeda, M., Matsui, T., Imamura, M. & Tsukita, S. Expression level, subcellular distribution and rho-GDI binding affinity of merlin in comparison with Ezrin/Radixin/Moesin proteins. Oncogene 18, 4788–4797 (1999).

    Article  CAS  Google Scholar 

  15. Yamashita, T. & Tohyama, M. The p75 receptor acts as a displacement factor that releases Rho from Rho-GDI. Nat. Neurosci. 6, 461–467 (2003).

    Article  CAS  Google Scholar 

  16. Sherman, L. et al. Interdomain binding mediates tumor growth suppression by the NF2 gene product. Oncogene 15, 2505–2509 (1997).

    Article  CAS  Google Scholar 

  17. Bremer, J. et al. Axonal prion protein is required for peripheral myelin maintenance. Nat. Neurosci. 13, 310–318 (2010).

    Article  CAS  Google Scholar 

  18. Elder, G.A., Friedrich, V.L. Jr., Margita, A. & Lazzarini, R.A. Age-related atrophy of motor axons in mice deficient in the mid-sized neurofilament subunit. J. Cell Biol. 146, 181–192 (1999).

    Article  CAS  Google Scholar 

  19. Giovannini, M. et al. Conditional biallelic Nf2 mutation in the mouse promotes manifestations of human neurofibromatosis type 2. Genes Dev. 14, 1617–1630 (2000).

    CAS  PubMed  PubMed Central  Google Scholar 

  20. Feltri, M.L. et al. Conditional disruption of beta 1 integrin in Schwann cells impedes interactions with axons. J. Cell Biol. 156, 199–209 (2002).

    Article  CAS  Google Scholar 

  21. Hagel, C. et al. Polyneuropathy in neurofibromatosis 2: clinical findings, molecular genetics and neuropathological alterations in sural nerve biopsy specimens. Acta Neuropathol. 104, 179–187 (2002).

    Article  CAS  Google Scholar 

  22. Hanemann, C.O., Diebold, R. & Kaufmann, D. Role of NF2 haploinsufficiency in NF2-associated polyneuropathy. Brain Pathol. 17, 371–376 (2007).

    Article  CAS  Google Scholar 

  23. Jackson, S.J., Pryce, G., Diemel, L.T., Cuzner, M.L. & Baker, D. Cannabinoid-receptor 1 null mice are susceptible to neurofilament damage and caspase 3 activation. Neuroscience 134, 261–268 (2005).

    Article  CAS  Google Scholar 

  24. Morrison, J.H. et al. A monoclonal antibody to non-phosphorylated neurofilament protein marks the vulnerable cortical neurons in Alzheimer's disease. Brain Res. 416, 331–336 (1987).

    Article  CAS  Google Scholar 

  25. Iseki, C. et al. Rinsho Shinkeigaku [A case of neurofibromatosis type 2 (NF2) presenting with late–onset axonal polyneuropathy] 49, 419–423 (2009).

  26. Scherer, S.S. & Gutmann, D.H. Expression of the neurofibromatosis 2 tumor suppressor gene product, merlin, in Schwann cells. J. Neurosci. Res. 46, 595–605 (1996).

    Article  CAS  Google Scholar 

  27. Morrison, H. et al. The NF2 tumor suppressor gene product, merlin, mediates contact inhibition of growth through interactions with CD44. Genes Dev. 15, 968–980 (2001).

    Article  CAS  Google Scholar 

  28. Baader, S.L. & Schilling, K. Glutamate receptors mediate dynamic regulation of nitric oxide synthase expression in cerebellar granule cells. J. Neurosci. 16, 1440–1449 (1996).

    Article  CAS  Google Scholar 

  29. Malin, S.A., Davis, B.M. & Molliver, D.C. Production of dissociated sensory neuron cultures and considerations for their use in studying neuronal function and plasticity. Nat. Protoc. 2, 152–160 (2007).

    Article  CAS  Google Scholar 

  30. Watanabe, S.Y. et al. Calcium phosphate–mediated transfection of primary cultured brain neurons using GFP expression as a marker: application for single neuron electrophysiology. Neurosci. Res. 33, 71–78 (1999).

    Article  CAS  Google Scholar 

  31. Jankowski, J., Miething, A., Schilling, K. & Baader, S.L. Physiological purkinje cell death is spatiotemporally organized in the developing mouse cerebellum. Cerebellum 8, 277–290 (2009).

    Article  Google Scholar 

  32. Michailov, G.V. et al. Axonal neuregulin-1 regulates myelin sheath thickness. Science 304, 700–703 (2004).

    Article  CAS  Google Scholar 

  33. Mundegar, R.R., Franke, E., Schafer, R., Zweyer, M. & Wernig, A. Reduction of high background staining by heating unfixed mouse skeletal muscle tissue sections allows for detection of thermostable antigens with murine monoclonal antibodies. J. Histochem. Cytochem. 56, 969–975 (2008).

    Article  CAS  Google Scholar 

  34. Mulisch, M.W.U. Romeis–Mikroskopische Technik (Spektrum Akademischer Verlag, 2010).

  35. Xia, R.H., Yosef, N. & Ubogu, E.E. Dorsal caudal tail and sciatic motor nerve conduction studies in adult mice: technical aspects and normative data. Muscle Nerve 41, 850–856 (2010).

    Article  Google Scholar 

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Acknowledgements

The authors would like to thank U. Petz, C. Poser and S. Ramrath for their expert technical assistance, H. Rosemann, F. Kaufmann and D. Galendo for their skilled breeding and husbandry of animals, and R.E. Ferner for discussions and support. Mpz-cre mice were kindly provided M.L. Feltri (Hunter James Kelly Research Institute). This work was supported by Sonderforschungsbereich 604, Deutsche Forschungsgemeinschaft MO 1421/2–1 and Krebshilfe 107089. A.S. is recipient of a Young Investigator Award from the Children's Tumor Foundation.

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Authors

Contributions

A.S. and H.M. conceived and designed the study. H.M. supervised the experimental program and prepared the manuscript. A.S. performed and analyzed the majority of the experiments and prepared the manuscript. S.L.B. performed the nerve section analysis of both knockout mice and patient biopsies, as well as their analysis. M.N.-K. and M.G. generated the Nf2-iso1−/− and Nf2-iso2−/− mice. R.B. designed the electrophysiological experiments and participated in data acquisition. C.G. and D.H.G. synthesized isoform-specific merlin antibodies. A.Z. and M.J.J. participated in the behavioral analysis of merlin knockout mice and the preparation of primary cell cultures. S.S. conducted nucleotide exchange and binding assays. X.-P.D. and D.B.P. provided tissue samples of Mpz-cre; Nf2loxP/loxP mice. C.H. and V.-F.M. provided NF2 patient biopsy sections for immunohistochemistry. C.O.H. provided NF2 patient biopsy sections for ultrastructural analysis. J.W. and J.M.S. performed the ultrastructural analysis of human NF2 patient biopsies.

Corresponding author

Correspondence to Helen Morrison.

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The authors declare no competing financial interests.

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Supplementary Figures 1–9 and Supplementary Table 1 (PDF 4832 kb)

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Schulz, A., Baader, S., Niwa-Kawakita, M. et al. Merlin isoform 2 in neurofibromatosis type 2–associated polyneuropathy. Nat Neurosci 16, 426–433 (2013). https://doi.org/10.1038/nn.3348

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