Egr1 Effects On C2C12 Differentiation

The molecular mechanism of muscle development and differentiation has always been a hot topic in life science.To clarify the molecular mechanism of muscle development and differentiation is of great significance to understand the process of muscle development and repair muscle injury,to the treatment of diseases such as muscular atrophy and myopenia.Early growth response 1(Egr1),as a transcription factor,plays important roles in many biological processes,such as cell proliferation,differentiation,apoptosis and so on.Egr1 can bind to the promoter region of MYOG and promote the cultured bovine skeletal muscle satellite cells differentiation by regulating MYOG expression,which suggests that Egr1 may be involved in the regulation of skeletal muscle development.However,its effects on C2C12 cells differentiation remains unclear.C2C12 is an ideal cell model for studying muscle development.The purpose of the study is to elucidate the effect of Egr1 on C2C12 differentiation,and to explore the relationship between Egr1 and muscle injury repair in vivo,in order to provide a theoretical basis for the molecular mechanism of muscle development and differentiation and the treatment of muscle injury repair.Research showed as follows:(1)Western blotting and immunofluorescence assays were used to determine the expression pattern and protein localization of Egr1 in C2C12 during its differentiation.(2)Egr1 expression was activated and inhibited using the CRISPR/Cas9 technique to explore its effects on C2C12 differentiation.(3)Induction of muscle injury by administration of bupivacaine to mice was used to indicate whether Egr1 plays a role in muscle regeneration.The results showed that:(1)Egr1 expression reached its peak on the day 5 of differentiation and then gradually decreased during C2C12 differentiation.Egr1 localized and expressed both in the cytoplasm and nucleus of C2C12 cells.Egr1 expression gradually increased when C2C12 induced to differentiation.(2)Myotube fusion rate,MYOG and MYH2 expression increased significantly when Egr1 were up-regulated during the C2C12 differentiation.Myotube fusion rate,MYOG and MYH2 expression decreased significantly when Egr1 were down-regulated during the C2C12 differentiation.(3)Pax7(paired box 7)expression increased gradually from Day 0 to Day 5 post-injury and reached its peak on Day 5.MYOG expression was low on Day 0 and Day 1 post-injury,peaked on Day 3.Then it gradually decreased and recovered to the undamaged level on Day 21.Egr1 exhibited an expression pattern similar to that of MYOG.In summary,the results showed that Egr1 promotes C2C12 differentiation and might play a role in the progress of mice muscle regeneration.