MiRNA-223 upregulated by MYOD inhibits myoblast proliferation by repressing IGF2 and facilitates myoblast differentiation by inhibiting ZEB1

Guihuan Li,Hongjia Ouyang,Xiquan Zhang,Bahareldin A Abdalla,Fan Hu,Jiao Yu,Qinghua Nie,Wen Luo

doi:10.1038/cddis.2017.479

Guihuan Li, Hongjia Ouyang + Show 6 more

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https://doi.org/10.1038/cddis.2017.479

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Abstract

Skeletal muscle differentiation can be regulated by various transcription factors and non-coding RNAs. In our previous work, miR-223 is differentially expressed in the skeletal muscle of chicken with different growth rates, but its role, expression and action mechanism in muscle development still remains unknown. Here, we found that MYOD transcription factor can upregulate miR-223 expression by binding to an E-box region of the gga-miR-223 gene promoter during avian myoblast differentiation. IGF2 and ZEB1 are two target genes of miR-223. The target inhibition of miR-223 on IGF2 and ZEB1 are dynamic from proliferation to differentiation of myoblast. miR-223 inhibits IGF2 expression only in the proliferating myoblast, whereas it inhibits ZEB1 mainly in the differentiating myoblast. The inhibition of IGF2 by miR-223 resulted in the repression of myoblast proliferation. During myoblast differentiation, miR-223 would be upregulated owing to the promoting effect of MYOD, and the upregulation of miR-223 would inhibit ZEB1 to promote myoblast differentiation. These results not only demonstrated that the well-known muscle determination factor MYOD can promote myoblast differentiation by upregulate miR-223 transcription, but also identified that miR-223 can influence myoblast proliferation and differentiation by a dynamic manner regulates the expression of its target genes.

Highlights

MicroRNAs are small non-coding RNA of 20–25 nucleotides that mainly transcript from introns or intergenic regions, having critical roles in the regulation of gene expression at posttranscriptional levels.[1]
To further understand the relationship between miR-223 and skeletal muscle development, we detected its expression in breast muscle during chicken embryonic development. miR-223 was gradually upregulated its expression from embryo day 10 (E10) to E13
The reporter activity inserted with Insulin-like growth factor-2 (IGF2)-3′-untranslated regions (3′-UTR) was significant higher in differentiating myoblasts compared with that in proliferating myoblasts (Figure 6i). These results suggested that the inhibition of miR-223 on IGF2 and Zinc finger E-box binding homeobox 1 (ZEB1) is different between myoblast proliferation and differentiation

Summary

Introduction

MicroRNAs (miRNAs) are small non-coding RNA of 20–25 nucleotides that mainly transcript from introns or intergenic regions, having critical roles in the regulation of gene expression at posttranscriptional levels.[1]. C/EBP alpha enhances miR-223 transcription activity, whereas NFI-A inhibits the transcription activity of miR-223.10 The upregulation of miR-223 expression will promote granulocyte and megakaryocyte generation, and the decline of miR-223 expression will cause hematopoietic stem cells to differentiate into erythrocyte.[11,12] In addition, miR-223 was confirmed to regulate cell proliferation, differentiation, migration and signal transduction in mammals.[13] the roles of miR-223 in muscle development still remain unclear. ZEB1 can inhibit the activity of viral gene transcription by targeting the

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