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Assay to Measure Nucleocytoplasmic Transport in Real Time within Motor Neuron-like NSC-34 Cells
Published on: May 16, 2017
The nuclear import receptor Kapβ2 modifies neurotoxicity mediated by poly(GR) in C9orf72-linked ALS/FTD
M E Cicardi1, V Kankate1, S Sriramoji1
1Weinberg ALS Center, Vickie and Jack Farber Institute for Neuroscience, Department of Neuroscience, Thomas Jefferson University, Philadelphia, PA, USA.
None:
Expanded intronic G4C2 repeats in the C9ORF72 gene cause amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). These intronic repeats are translated through a non-AUG-dependent mechanism into five different dipeptide repeat proteins (DPRs), including poly-glycine-arginine (GR), which is aggregation-prone and neurotoxic. Here, we report that Kapβ2 and GR interact, co-aggregating, in cultured neurons in-vitro and CNS tissue in-vivo. Importantly, this interaction significantly decreased the risk of death of cultured GR-expressing neurons. Downregulation of Kapβ2 is detrimental to their survival, whereas increased Kapβ2 levels mitigated GR-mediated neurotoxicity. As expected, GR-expressing neurons displayed TDP-43 nuclear loss. Raising Kapβ2 levels did not restore TDP-43 into the nucleus, nor did alter the dynamic properties of GR aggregates. Overall, our findings support the design of therapeutic strategies aimed at up-regulating Kapβ2 expression levels as a potential new avenue for contrasting neurodegeneration in C9orf72-ALS/FTD.
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