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. Issue 6 (October 2014)

• Record Type: Journal Article
• Authors: Highley, J. Robin; Kirby, Janine; Jansweijer, Joeri A.; Webb, Philip S.; Hewamadduma, Channa A.; Heath, Paul R.; Higginbottom, Adrian; Raman, Rohini; Ferraiuolo, Laura; Cooper‐Knock, Johnathan; McDermott, Christopher J.; Wharton, Stephen B.; Shaw, Pamela J.; Ince, Paul G.
• Is Part Of: Neuropathology & applied neurobiology. Volume 40:Issue 6(2014)
• Page Start: 670
• Page End: 685
• Publication Date: 2014-10
• Subjects: Nervous system -- Diseases -- Pathology -- Periodicals; Nervous system -- Diseases -- Periodicals; 616.8
• DOI: 10.1111/nan.12148
• Languages: English
• ISSNs: 0305-1846

Abstract

<abstract abstract-type="main"> <title> <x xml:space="preserve">Abstract</x> </title> <sec id="nan12148-sec-0001" sec-type="section"> <title>Aims</title> <p>Loss of nuclear TDP‐43 characterizes sporadic and most familial forms of amyotrophic lateral sclerosis (ALS). TDP‐43 (encoded by <italic>TARDBP</italic>) 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) <italic>TARDBP</italic> mutations (mt<italic>TARDBP</italic>) are associated with aberrant RNA splicing using patient‐derived fibroblasts.</p> </sec> <sec id="nan12148-sec-0002" sec-type="section"> <title>Methods</title> <p>Affymetrix 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 NSC34 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<italic>TARDBP</italic>‐associated, sporadic and mutant <italic>SOD1</italic>‐associated ALS.</p> </sec> <sec id="nan12148-sec-0003" sec-type="section"> <title>Results</title> <p>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 NSC34 cells. Fibroblasts with mt<italic>TARDBP</italic> 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 <italic>SOD1</italic><italic>‐</italic>related ALS.</p> </sec> <sec id="nan12148-sec-0004" sec-type="section"> <title>Conclusion</title> <p>Loss of nuclear TDP‐43 is associated with RNA processing abnormalities in ALS motor neurones, patient‐derived cells with mt<italic>TARDBP</italic>, 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.</p> </sec> </abstract>