Alternative Splicing Factor ASF/SF2 is Down Regulated in Inflamed Muscle
Overview
Affiliations
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 alpha (TNFalpha), 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 beta-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 TNFalpha-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.
Roesmann F, Muller L, Klaassen K, Hess S, Widera M Viruses. 2024; 16(6).
PMID: 38932230 PMC: 11209495. DOI: 10.3390/v16060938.
Lee F, Harris C, Alper S J Mol Biol. 2024; 436(8):168497.
PMID: 38369277 PMC: 11001520. DOI: 10.1016/j.jmb.2024.168497.
Costa R, Rodia M, Zini N, Pegoraro V, Marozzo R, Capanni C Mol Cell Biochem. 2021; 476(4):1797-1811.
PMID: 33452620 PMC: 7940345. DOI: 10.1007/s11010-020-04023-y.
Liu M, Saredy J, Zhang R, Shao Y, Sun Y, Yang W Front Immunol. 2020; 11:554301.
PMID: 33193322 PMC: 7604447. DOI: 10.3389/fimmu.2020.554301.
Paz S, Ritchie A, Mauer C, Caputi M Cytokine Growth Factor Rev. 2020; 57:19-26.
PMID: 33160830 PMC: 7897272. DOI: 10.1016/j.cytogfr.2020.10.008.