Expression of myostatin in postnatal mouse head and leg muscles

Abstract

ObjectiveMyostatin (Mstn) is a member of the transforming growth factor‐β (TGF‐β) family that regulates muscle differentiation and growth. Thyroid hormone receptor alpha (TRα) effects to the producing the myogenic protein in muscle development. We aimed to identify the relationships between Mstn, TRα, and myosin heavy chain (MyHC) isoforms expression during postnatal mouse development.MethodsWe investigated the expression of Mstn, TRα, and MyHCs (embryonic, slow, IIa, IIb, and IIx) using quantitative real‐time RT‐PCR and ELISA (Mstn) in postnatal mouse muscles between day 0 and day 10. We also examined the correlations between Mstn, TR and MyHCs during early development of mouse masseter muscle (MM) and of the rectus femoris muscle (RFM).ResultsDistinct Mstn mRNA expression patterns were observed in the two muscles, despite nearly non‐significant changes in the Mstn protein abundance in MM. The expression pattern of the TRα mRNA in the MM differed from that observed in the RFM. The expression of the MyHC IIa, IIb and IIx mRNAs increased in the MM and decreased in the RFM from day 0 to day 10, while embryonic fiber MyHC mRNA expression was similar in both muscle types. Principal component analysis showed that the existence of correlation between; 1) TRα and MyHC, 2) Mstn and MyHC, and 3) TRα and Mstn. They were different according to two muscles. Cluster analyses identified the distinct clusters: cluster 1, days 0–4 for the MM and day 0 for the RFM; cluster 2, day 6 for the MM and day 2 for the RFM; and cluster 3, days 8–10 for the MM and days 4–10 for the RFM.ConclusionsThese data suggest that TRα potentially influences MyHC expression in both muscle types. In addition, Mstn has a limited effect in the MM related to the expression of individual MyHCs, as opposed to its role in the RFM, at early postnatal developmental stages. TRα could be involved in regulating both the temporal expression of MyHCs and Mstn at early postnatal stages in the mouse head and leg muscles.Support or Funding Informationnone