Progressive multifocal leukoencephalopathy (PML) is a demyelinating disease triggered by infection with the human gliotropic JC virus (JCV). Due to the human-selective nature of the virus, there are no animal models available to investigate JCV pathogenesis. To address this issue, we developed mice with humanized white matter by engrafting human glial progenitor cells (GPCs) into neonatal immunodeficient and myelin-deficient mice. Intracerebral delivery of JCV resulted in infection and subsequent demyelination of these chimeric mice. Human GPCs and astrocytes were infected more readily than oligodendrocytes, and viral replication was noted primarily in human astrocytes and GPCs rather than oligodendrocytes, which instead expressed early viral T antigens and exhibited apoptotic death. Engraftment of human GPCs in normally myelinated and immunodeficient mice resulted in humanized white matter that was chimeric for human astrocytes and GPCs. JCV effectively propagated in these mice, which indicates that astroglial infection is sufficient for JCV spread. Sequencing revealed progressive mutation of the JCV capsid protein VP1 after infection, suggesting that PML may evolve with active infection. These results indicate that the principal CNS targets for JCV infection are astrocytes and GPCs and that infection is associated with progressive mutation, while demyelination is a secondary occurrence, following T antigen–triggered oligodendroglial apoptosis. More broadly, this study provides a model by which to further assess the biology and treatment of human-specific gliotropic viruses.
Yoichi Kondo, Martha S. Windrem, Lisa Zou, Devin Chandler-Militello, Steven J. Schanz, Romane M. Auvergne, Sarah J. Betstadt, Amy R. Harrington, Mahlon Johnson, Alexander Kazarov, Leonid Gorelik, Steven A. Goldman
Submitter: Kamel Khalili | kkhalili@temple.edu
Authors: Kamel Khalili, Martyn K. White, Jennifer Gordon, and Joseph R. Berger
Department of Neuroscience, Temple University School of Medicine 3500 N. Broad Street, Philadelphia, PA 19140
Published December 17, 2014
Investigation of the demyelinating disease, progressive multifocal leukoencephalopathy (PML) is severely hampered by lack of an animal model, and the paper by Kondo et al is a hallmark advance, which deserves some further mention and discussion. PML is a severe demyelinating disease of CNS, where JC virus (JCV) replicates productively in glial cells leading to cell death (1, 2). JCV has a strict host range for replication (3) and only grows in cultured human astrocytes (4, 5) or oligodendrocytes (6). However, lack of a suitable animal model for PML due to JCV’s failure to replicate in non-human hosts hampers research (3). Nevertheless, some progress has been made (7-11) but no model yet has allowed JCV infection of CNS or modeled PML pathogenesis. The human glial chimeric mouse model of Kondo et al (12) described here is perhaps the most significant success so far with engrafted human glial progenitor cells (GPCs) generating humanized forebrain glial populations (12). When injected intracerebrally with JCV, productive infection and demyelination were observed. JCV was spread by infection of GPCs and astrocytes rather than oligodendrocytes, which expressed T-Ag and died by apoptosis as previously reported for oligodendrocytes in culture (6, 13) leading to a secondary demyelination.
The new mouse model shows important differences to clinical PML where oligodendrocytes express VP1 (14, 15) and contain large numbers of JC virions (inclusion bodies) indicating robust infection (15, 16), while astrocytes express VP1 (15, 17) and contain virions (18, 19) but to a lesser extent. The explanation for this difference is not clear but may be related to important differences between the two situations. Firstly, the mice received direct intracerebral inoculation of high-titre virus while clinical PML involves indirect delivery to the brain that may occur over a long period of time before the virus causes PML. Secondly, the nature of immunosuppression in the chimeric mouse differs from that in humans who are predisposed to PML (20-22). Finally, the engrafted cells in the mouse are human but all other cells, e.g., blood cells are mouse origin and not susceptible to JCV infection, which is a significant limitation because it will preclude more detailed studies of aspects of PML disease manifestation (23). These shortcomings notwithstanding, the mouse model generated by Kondo and colleagues stands out as a major breakthrough in the field and will likely be a starting point in development of more sophisticated and relevant models.
REFERENCES
1. Berger JR. The clinical features of PML. Cleve Clin J Med. 2011;78 Suppl2:S8-12.
2. White MK, Khalili K. Pathogenesis of progressive multifocal leukoencephalopathy--revisited. J Infect Dis. 2011;203(5):578-586.
3. Feigenbaum L, Khalili K, Major E, Khoury G. Regulation of the host range of human papovavirus JCV. Proc Natl Acad Sci USA 1987;84(11):3695-3698.
4. Major EO, Vacante DA. Human fetal astrocytes in culture support the growth of the neurotropic human polyomavirus, JCV. J Neuropathol Exp Neurol. 1989;48(4):425-436.
5. Radhakrishnan S, Otte J, Enam S, Del Valle L, Khalili K, Gordon J. JC virus-induced changes in cellular gene expression in primary human astrocytes. J Virol. 2003;77(19):10638-10644.
6. Darbinyan A, Kaminski R, White MK, Darbinian-Sarkissian N, Khalili K. Polyomavirus JC infection inhibits differentiation of oligodendrocyte progenitor cells. J Neurosci Res. 2013;91(1):116-127.
7. Small JA, Scangos GA, Cork L, Jay G, Khoury G. The early region of human papovavirus JC induces dysmyelination in transgenic mice. Cell 1986;46(1):13-18.
8. Haas S, Haque NS, Beggs AH, Khalili K, Knobler RL, Small J. Expression of the myelin basic protein gene in transgenic mice expressing human neurotropic virus, JCV, early protein. Virology 1994;202(1):89-96.
9. Tan CS, Broge TA, Seung E, Vrbanac V, Viscidi R, Gordon J, Tager AM, Koralnik IJ. Detection of JC virus-specific immune responses in a novel humanized mouse model. PLoS One 2013;8(5): e64313.
10. Axthelm MK, Koralnik IJ, Dang X, Wüthrich C, Rohne D, Stillman IE, Letvin NL. Meningoencephalitis and demyelination are pathologic manifestations of primary polyomavirus infection in immunosuppressed rhesus monkeys. J Neuropathol Exp Neurol. 2004;63(7):750-758.
11. Matoba T, Orba Y, Suzuki T, Makino Y, Shichinohe H, Kuroda S, Ochiya T, Itoh H, Tanaka S, Nagashima K, Sawa H. An siRNA against JC virus (JCV) agnoprotein inhibits JCV infection in JCV-producing cells inoculated in nude mice. Neuropathology 2008;28(3):286-294.
12. Kondo Y, Windrem MS, Zou L, Chandler-Militello D, Schanz SJ, Auvergne RM, Betstadt SJ, Harrington AR, Johnson M, Kazarov A, Gorelik L, Goldman SA. Human glial chimeric mice reveal astrocytic dependence of JC virus infection. J Clin Invest. 2014(12);124:5323-5336.
13. Tretiakova A, Krynska B, Gordon J, Khalili K. Human neurotropic JC virus early protein deregulates glial cell cycle pathway and impairs cell differentiation. J Neurosci Res. 1999;55(5):588-599.
14. Jochum W, Weber T, Frye S, Hunsmann G, Lüke W, Aguzzi A. Detection of JC virus by anti-VP1 immunohistochemistry in brains with progressive multifocal leukoencephalopathy. Acta Neuropathol. 1997;94(3):226-231.
15. Del Valle L, Pina-Oviedo S. HIV disorders of the brain: pathology and pathogenesis. Front Biosci. 2006;11:718-732.
16. Major EO, Amemiya K, Tornatore CS, Houff SA, Berger JR. Pathogenesis and molecular biology of progressive multifocal leukoencephalopathy, the JC virus-induced demyelinating disease of the human brain. Clin Microbiol Rev. 1992;5(1):49-73.
17. Aksamit AJ, Sever JL, Major EO. Progressive multifocal leukoencephalopathy: JC virus detection by in situ hybridization compared with immunohistochemistry. Neurology 1986;36(4):499-504.
18. Watanabe I, Preskorn SH. Virus-cell interaction in oligodendroglia, astroglia and phagocyte in progressive multifocal leukoencephalopathy. An electron microscopic study. Acta Neuropathol. 1976;36(2):101-115.
19. Mazlo M, Ressetar HG, Stoner GL. The neuropathology and pathogenesis of progressive multifocal leukoencephalopathy. In: Khalili K and Stoner GL, eds. Human polyomaviruses: molecular and clinical perspectives. New York: John Wiley & Sons, Inc.; 2001:257-336.
20. Beltrami S, Gordon J. Immune surveillance and response to JC virus infection and PML. J Neurovirol. 2014;20(2):137-149.
21. Koralnik IJ, Du Pasquier RA, Letvin NL. JC virus-specific cytotoxic T lymphocytes in individuals with progressive multifocal leukoencephalopathy. J Virol. 2001;75(7):3483-3487.
22. Du Pasquier RA, Kuroda MJ, Zheng Y, Jean-Jacques J, Letvin NL, Koralnik IJ. A prospective study demonstrates an association between JC virus-specific cytotoxic T lymphocytes and the early control of progressive multifocal leukoencephalopathy. Brain 2004;127(9):1970-1978.
23. Haley SA, Atwood WJ. 2014. An animal model for progressive multifocal leukoencephalopathy. J Clin Invest. 124(12):5103-5106.