Human glial chimeric model for drug candidate assessment in human gliotrophic viral infections and progressive multifocal encephalopathy
The present invention is directed to a method of assessing in vivo human glial cell response to pathogenic infection that involves providing a non-human mammal either with at least 30% of its glial cells in its corpus callosum being human glial cells and/or with at least 5% of its glial cells its brain and brain stem white matter being human glial cells, subjecting the non-human mammal to pathogenic infection and assessing the in vivo human glial cell response to pathogenic infection. A method of identifying therapeutic agents for the pathogenic infection as well as forms of the non-human mammal having a pathogenic brain infection are also disclosed.
1. A method for infecting in vivo a human astrocyte with JC virus, said method comprising;
providing a non-human mammal comprising with at least 30% of its glial cells in its corpus callosum being human glial cells and/or with at least 5% of its glial cells in its brain white matter being human glial cells and
administering intracallosally JC virus into the white matter in the non-human mammal, wherein the JC virus infects and propagates within the human astrocytes and parenchymal progenitor cells of the white mater in the non-human mammal with an efficiency greater than in human oligodendrocytes in the non-human mammal.
2. The method of claim 1 further comprising:
administering a candidate therapeutic agent to the non-human mammal prior to, concurrent with, or after said infecting.
3. The method according to claim 1 , wherein at least 15% of all of the glial cells in the white matter of the mammal's brain and/or brain stem are human glial cells.
4. The method according to claim 3 , wherein the white matter is cerebellar white matter and at least 50% of all glial cells in the cerebellar white matter are human glial cells.
5. The method according to claim 1 , wherein at least 50% of all of the glial cells in the corpus callosum of the mammal are human glial cells.
6. The method according to claim 5 , wherein at least 70% of all of the glial cells in the corpus callosum of the mammal are human glial cells.
7. The method of claim 2 further comprising:
determining, as a result of said administering, a therapeutic modification of the human astrocytes in response to the pathogenic infection using a metric selected from the group consisting of morphology, immunophenotype, transcriptionally-regulated reporters, gene expression profiles, mitotic rate, mitotic fraction, metabolic rate, mitochondrial function, oxidative state, telomerase activity, apoptotic index, and net cell survival.
8. The method of claim 1 further comprising:
determining the behavior or fate of the human astrocytes using a metric selected from the group consisting of morphology, immunophenotype, transcriptionally-regulated reporters, gene expression profiles, mitotic rate, mitotic fraction, metabolic rate, mitochondrial function, oxidative state, telomerase activity, apoptotic index, and net cell survival.
9. The method according to claim 8 , wherein morphology is examined as reflected in cell size, fiber outgrowth, length, complexity, and indices of myelination efficiency.
10. The method according to claim 9 , wherein morphology is examined as reflected in G-ratio, axonal ensheathment efficiency, proportion of axons myelinated, number of axons myelinated per oligodendrocyte, or number of myelin wraps per axon.
11. The method according to claim 8 , wherein immunophenotype is examined using immunocytochemistry, immunoblotting, flow cytometry, or fluorescence-activated cell sorting.
12. The method according to claim 8 , wherein transcriptionally-regulated reporters are examined using promoter/enhancer-driven reporters in enzymatic or fluorescent form.
13. The method according to claim 8 , wherein gene expression profiles are examined using microarrays, real-time PCR, or protein expression profiling.