Alternative splicing factor ASF/SF2 is down regulated in inflamed muscle
- Z Xiong1,2,
- A Shaibani3,4,
- Y-P Li3,
- Y Yan2,
- S Zhang1,2,
- Y Yang2,
- F Yang1,2,
- H Wang1,3,5,
- X-F Yang1,2,3,6
- 1Laboratory of Immunopathology, Department of Pharmacology, Temple University School of Medicine, Philadelphia, Pennsylvania, USA
- 2Laboratory of Immunopathology, Baylor College of Medicine, Houston, Texas, USA
- 3Department of Medicine, Baylor College of Medicine
- 4Nerve & Muscle Center of Texas, St Luke’s Episcopal Hospital, Houston
- 5Biology of Inflammation Center, Section of Atherosclerosis and Lipoprotein Research, Baylor College of Medicine
- 6Department of Immunology, Baylor College of Medicine
- Correspondence to: X-F Yang Department of Pharmacology, Temple University School of Medicine, 3420 N Broad Street, MRB Room 300, Philadelphia, PA 19140, USA; franklinxf_yang{at}yahoo.com
- Accepted 11 December 2005
- Published Online First 30 March 2006
Abstract
Background: In our recent studies, alternative splicing has been shown to have a major role in inflammation and autoimmune muscle diseases.
Aim: To examine the novel hypothesis that the expression of an essential alternative splicing factor, alternative splicing factor 2 (ASF/SF2), is modulated in muscle inflammation.
Methods: ASF/SF2 expression in muscle biopsy samples from eight patients with inflammatory myopathy and six non-myositic controls was determined by using western blot with anti-ASF/SF2 antibodies. To further elucidate the mechanism of reduced ASF/SF2 expression in inflamed muscle, differentiated C2C12 myotubes were stimulated with proinflammatory cytokine tumour necrosis factor α (TNFα), followed by western blot analysis of ASF/SF2 expression.
Results: ASF/SF2 expression in the muscle biopsy samples from patients with inflammatory myopathy was found to be lower (mean of relative densitometric units 41.1 (2SD 20.7)) than that of the non-myositic controls (mean of relative densitometric units 76.7 (39.6); p<0.05). In addition to this, ASF/SF2 expression was seen to be significantly down regulated (sevenfold) in C2C12 myotubes compared with expression variations in the β-actin control (0.62-fold; mean 1.22 (0.40); p<0.05).
Conclusion: Collectively, it is shown, for the first time, that alternative splicing factor ASF/SF2 is down regulated in autoimmune inflammatory myositis—potentially via a TNFα-mediated pathway. The development of (1) novel autoantigen isoform microarrays for disease diagnosis and prognosis; (2) novel autoantigen-tolerising treatments for autoimmune diseases; and (3) novel splicing-redirection treatments can be facilitated by the ongoing study of alternative splicing of autoantigen transcripts.
- ASF/SF2, alternative splicing factor 2
- mRNA, messenger RNA
- PM, polymyositis
- SR protein, serine/arginine-rich protein
- TNFα, tumour necrosis factor α
Footnotes
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Published Online First 30 March 2006








