Downregulation of expression and activity levels of the astroglial glutamate transporter EAAT2 is thought to be implicated in motor neuron excitotoxicity in amyotrophic lateral sclerosis (ALS). We previously reported that EAAT2 is cleaved by caspase-3 at the cytosolic C-terminus domain, impairing the transport activity and generating a proteolytic fragment found to be SUMO1 conjugated (CTE-SUMO1). We show here that this fragment accumulates in the nucleus of spinal cord astrocytes in vivo throughout the disease stages of the SOD1-G93A mouse model of ALS. In vitro expression in spinal cord astrocytes of the C-terminus peptide of EAAT2 (CTE), which was artificially fused to SUMO1 (CTE-SUMO1fus) to mimic the endogenous SUMOylation reaction, recapitulates the nuclear accumulation of the fragment seen in vivo and causes caspase-3 activation and axonal growth impairment in motor neuron-derived NSC-34 cells and primary motor neurons co-cultured with CTE-SUMO1fus-expressing spinal cord astrocytes. This indicates that CTE-SUMO1fus could trigger non-cell autonomous mechanisms of neurodegeneration. Prolonged nuclear accumulation of CTE-SUMO1fus in astrocytes leads to their degeneration, although the time frame of the cell-autonomous toxicity is longer than the one for the indirect toxic effect on motor neurons. As more evidence on the implication of SUMO substrates in neurodegenerative diseases emerges, our observations strongly suggest that the nuclear accumulation in spinal cord astrocytes of a SUMOylated proteolytic fragment of the astroglial glutamate transporter EAAT2 could take part to the pathogenesis of ALS and suggest a novel, unconventional role for EAAT2 in motor neuron degeneration in ALS.
Motor neuron impairment mediated by a sumoylated fragment of the glial glutamate transporter EAAT2.
Specimen part
View SamplesTo determine the differential expression of KRAS-variant HNSCC (head and neck squamous cell carcinoma) cell lines.
A 3'-UTR KRAS-variant is associated with cisplatin resistance in patients with recurrent and/or metastatic head and neck squamous cell carcinoma.
Specimen part, Cell line
View SamplesThis SuperSeries is composed of the SubSeries listed below.
Foxl2 functions in sex determination and histogenesis throughout mouse ovary development.
Sex, Subject
View SamplesComparison of Foxl2-null ovaries to wildtype ovaries, ovaries lacking Wnt4 or Kit, or testes, throughout mouse development.
Foxl2 functions in sex determination and histogenesis throughout mouse ovary development.
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