Molecular mechanism of sphingosine-1-phosphate action in Duchenne muscular dystrophy.
Duchenne muscular dystrophy (DMD) is a lethal muscle-wasting disease. Studies in Drosophila showed that genetic increase of the levels of the bioactive sphingolipid sphingosine-1-phosphate (S1P) or delivery of 2-acetyl-5-tetrahydroxybutyl imidazole (THI), an S1P lyase inhibitor, suppresses dystrophic muscle degeneration. In the dystrophic mouse (mdx), upregulation of S1P by THI increases regeneration and muscle force. S1P can act as a ligand for S1P receptors and as a histone deacetylase (HDAC) inhibitor. Because Drosophila has no identified S1P receptors and DMD correlates with increased HDAC2 levels, we tested whether S1P action in muscle involves HDAC inhibition. Here we show that beneficial effects of THI treatment in mdx mice correlate with significantly increased nuclear S1P, decreased HDAC activity and increased acetylation of specific histone residues. Importantly, the HDAC2 target microRNA genes miR-29 and miR-1 are significantly upregulated, correlating with the downregulation of the miR-29 target Col1a1 in the diaphragm of THI-treated mdx mice. Further gene expression analysis revealed a significant THI-dependent decrease in inflammatory genes and increase in metabolic genes. Accordingly, S1P levels and functional mitochondrial activity are increased after THI treatment of differentiating C2C12 cells. S1P increases the capacity of the muscle cell to use fatty acids as an energy source, suggesting that THI treatment could be beneficial for the maintenance of energy metabolism in mdx muscles.
Molecular and Cellular Biology Graduate Program, University of Washington, Seattle, WA 98195-7350, USA.
Diem-Hang
DH
Nguyen-Tran
Nitai C
NC
Hait
Henrik
H
Sperber
Junlin
J
Qi
Karin
K
Fischer
Nick
N
Ieronimakis
Mario
M
Pantoja
Aislinn
A
Hays
Jeremy
J
Allegood
Morayma
M
Reyes
Sarah
S
Spiegel
Hannele
H
Ruohola-Baker
D000107:Acetylation; D000446:Aldehyde-Lyases / Q000037:antagonists & inhibitors; D000818:Animals; D002467:Cell Nucleus / Q000378:metabolism; D015536:Down-Regulation; D006655:Histone Deacetylases / Q000378:metabolism; D006657:Histones / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology*; D007249:Inflammation; D008246:Lysophospholipids / Q000378:metabolism*; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018101:Mice, Inbred mdx; D035683:MicroRNAs / Q000378:metabolism; D008928:Mitochondria / Q000378:metabolism; D018482:Muscle, Skeletal / Q000378:metabolism; D020388:Muscular Dystrophy, Duchenne / Q000378:metabolism*; D020411:Oligonucleotide Array Sequence Analysis; D010641:Phenotype; D011494:Protein Kinases / Q000378:metabolism; D012038:Regeneration; D012518:Sarcomeres / Q000378:metabolism; D013110:Sphingosine / Q000031:analogs & derivatives* / Q000378:metabolism; D014018:Tissue Distribution
D006657:Histones; D007093:Imidazoles; D008246:Lysophospholipids; C547014:MIRN29 microRNA, mouse; D035683:MicroRNAs; C517731:Mirn1 microRNA, mouse; C060506:sphingosine 1-phosphate; C049929:2-acetyl-4(5)-tetrahydroxybutylimidazole; D011494:Protein Kinases; C579730:titin protein, mouse; D006655:Histone Deacetylases; D000446:Aldehyde-Lyases; C022649:sphingosine 1-phosphate lyase (aldolase); D013110:Sphingosine
Dystrophin; HDAC; S1P; THI; dys; mdx