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Loss of nuclear TDP ‐43 in amyotrophic lateral sclerosis ( ALS ) causes altered expression of splicing machinery and widespread dysregulation of RNA splicing in motor neurones
Author(s) -
Highley J. Robin,
Kirby Janine,
Jansweijer Joeri A.,
Webb Philip S.,
Hewamadduma Channa A.,
Heath Paul R.,
Higginbottom Adrian,
Raman Rohini,
Ferraiuolo Laura,
CooperKnock Johnathan,
McDermott Christopher J.,
Wharton Stephen B.,
Shaw Pamela J.,
Ince Paul G.
Publication year - 2014
Publication title -
neuropathology and applied neurobiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.538
H-Index - 95
eISSN - 1365-2990
pISSN - 0305-1846
DOI - 10.1111/nan.12148
Subject(s) - tardbp , rna splicing , amyotrophic lateral sclerosis , exon , biology , spliceosome , rna binding protein , alternative splicing , microbiology and biotechnology , small hairpin rna , gene expression , rna , sod1 , gene , genetics , medicine , pathology , mutant , disease
Aims Loss of nuclear TDP ‐43 characterizes sporadic and most familial forms of amyotrophic lateral sclerosis ( ALS ). TDP ‐43 (encoded by TARDBP ) has multiple roles in RNA processing. We aimed to determine whether (1) RNA splicing dysregulation is present in lower motor neurones in ALS and in a motor neurone‐like cell model; and (2) TARDBP mutations (mt TARDBP ) are associated with aberrant RNA splicing using patient‐derived fibroblasts. Methods A ffymetrix exon arrays were used to study mRNA expression and splicing in lower motor neurones obtained by laser capture microdissection of autopsy tissue from individuals with sporadic ALS and TDP ‐43 proteinopathy. Findings were confirmed by quantitative reverse transcription‐polymerase chain reaction ( qRT ‐ PCR ) and in NSC 34 motor neuronal cells following shRNA ‐mediated TDP ‐43 depletion. Exon arrays and immunohistochemistry were used to study mRNA splicing and TDP ‐43 expression in fibroblasts from patients with mt TARDBP ‐associated, sporadic and mutant SOD1 ‐associated ALS . Results We found altered expression of spliceosome components in motor neurones and widespread aberrations of mRNA splicing that specifically affected genes involved in ribonucleotide binding. This was confirmed in TDP ‐43‐depleted NSC 34 cells. Fibroblasts with mt TARDBP showed loss of nuclear TDP ‐43 protein and demonstrated similar changes in splicing and gene expression, which were not present in fibroblasts from patients with sporadic or SOD1 ‐ related ALS . Conclusion Loss of nuclear TDP ‐43 is associated with RNA processing abnormalities in ALS motor neurones, patient‐derived cells with mt TARDBP , and following artificial TDP ‐43 depletion, suggesting that splicing dysregulation directly contributes to disease pathogenesis. Key functional pathways affected include those central to RNA metabolism.