Siranosian JJ, Nery FC, Alves CRR, Siranosian BA, Lyons NJ, Eichelberger EJ, Garner R, Da Silva Duarte Lepez S, Johnstone AJ, Subramanian A, Swoboda KJ. Whole-blood dysregulation of actin-cytoskeleton pathway in adult spinal muscular atrophy patients.
Ann Clin Transl Neurol 2020;
7:1158-1165. [PMID:
32558393 PMCID:
PMC7359125 DOI:
10.1002/acn3.51092]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/10/2020] [Revised: 05/09/2020] [Accepted: 05/14/2020] [Indexed: 01/21/2023] Open
Abstract
OBJECTIVE
Recent advances in therapeutics have improved prognosis for severely affected spinal muscular atrophy (SMA) type 1 and 2 patients, while the best method of treatment for SMA type 3 patients with later onset of disease is unknown. To better characterize the SMA type 3 population and provide potential therapeutic targets, we aimed to understand gene expression differences in whole blood of SMA type 3 patients (n = 31) and age- and gender-matched controls (n = 34).
METHODS
We performed the first large-scale whole blood transcriptomic screen with L1000, a rapid, high-throughput gene expression profiling technology that uses 978 landmark genes to capture a representation of the transcriptome and predict expression of 9196 additional genes.
RESULTS
The primary downregulated KEGG pathway in adult SMA type 3 patients was "Regulation of Actin Cytoskeleton," and downregulated expression of key genes in this pathway, including ROCK1, RHOA, and ACTB, was confirmed in the same whole blood samples using RT-qPCR. SMA type 3 patient-derived fibroblasts had lower expression of these genes compared to control fibroblasts from unaffected first-degree relatives. Overexpression of SMN levels using an AAV vector in fibroblasts did not normalize ROCK1, RHOA, and ACTB mRNA expression, indicating the involvement of additional genes in cytoskeleton dynamic regulation.
INTERPRETATION
Our findings from whole blood and patient-derived fibroblasts suggest SMA type 3 patients have decreased expression of actin cytoskeleton regulators. These observations provide new insights and potential therapeutic targets for SMA patients with longstanding denervation and secondary musculoskeletal pathophysiology.
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