Antisense inhibition of myoD expression in regenerating rat soleus muscle is followed by an increase in the mRNA levels of myoD, myf-5 and myogenin and by a retarded regeneration.
It has been reported that muscles of myoD-/- mice present a lower potential to regenerate, but there are no reports on the effect of acute interference with myoD expression limited in space and time to only a particular regenerating muscle. Here we relied on antisense inhibition of this factor. Four different oligos were tested. The suppression of regeneration indices (the expression of desmin, the formation of myotubes and the initiation of endplates) was the most pronounced, with the oligomer targeting a region encompassing the translation start site of myoD. A mixed backbone phosphorothioate-phosphate diester oligo (200 microl at 20 microM) was still detectable in the muscles 1 h after its administration and reverse transcription-polymerase chain reaction (RT-PCR) analysis showed that the level of the targeted 5' end of the myoD mRNA was selectively decreased. The level of myoD protein was also lowered. Four hours after the antisense treatment, when the oligos were no longer detectable, the myoD mRNA level was restored and 24 h later it exceeded controls together with that of myf-5 and myogenin. After 4 weeks, the antisense-treated soleus muscles were similar to the control-treated and the untreated regenerated soleus with respect to fiber types and motor endplates, however, they contained smaller fibers which reflected the asynchronity of regeneration. This shows that successfully targeted simple antisense oligonucleotides can be used as selective tools for inhibition of individual factors in studying the process of muscle regeneration.
Zádor
Erno
E
Institute of Biochemistry, Albert Szent-Györgyi Medical Center, University of Szeged, H-6701, Szeged, Hungary. emo@bioch.szote.u-szged.hu
Bottka
Sándor
S
Wuytack
Frank
F
D000818:Animals; D001483:Base Sequence; D001973:Bromodeoxyuridine / Q000378:metabolism; D004268:DNA-Binding Proteins / Q000235:genetics; D003893:Desmin / Q000378:metabolism; D015870:Gene Expression; D051798:Inhibitor of Differentiation Protein 1; D051797:Inhibitor of Differentiation Protein 2; D008297:Male; D009124:Muscle Proteins / Q000235:genetics*; D018482:Muscle, Skeletal / Q000187:drug effects / Q000502:physiology*; D017570:MyoD Protein / Q000037:antagonists & inhibitors* / Q000235:genetics / Q000502:physiology; D051787:Myogenic Regulatory Factor 5; D018008:Myogenin / Q000235:genetics*; D018995:Myosin Heavy Chains / Q000378:metabolism; D020319:Oligodeoxyribonucleotides, Antisense / Q000235:genetics / Q000494:pharmacology*; D012333:RNA, Messenger / Q000235:genetics / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D012038:Regeneration / Q000187:drug effects / Q000235:genetics*; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors / Q000235:genetics
D004268:DNA-Binding Proteins; D003893:Desmin; C497454:ID1 protein, rat; C497451:Id2 protein, rat; D051798:Inhibitor of Differentiation Protein 1; D051797:Inhibitor of Differentiation Protein 2; D009124:Muscle Proteins; D017570:MyoD Protein; C503803:Myog protein, rat; D051787:Myogenic Regulatory Factor 5; D018008:Myogenin; D020319:Oligodeoxyribonucleotides, Antisense; D012333:RNA, Messenger; D012097:Repressor Proteins; D015534:Trans-Activators; D014157:Transcription Factors; D018995:Myosin Heavy Chains; D001973:Bromodeoxyuridine