Mechanical stretch regulates microRNA expression profile via NF-κB activation in C2C12 myoblasts

Abstract

MicroRNAs (miRNAs/miRs) and nuclear factor (NF)-κB activation are involved in mechanical stretch-induced skeletal muscle regeneration. However, there are a small number of miRNAs that have been reported to be associated with NF-κB activation during mechanical stretch-induced myogenesis. In the present study, C2C12 myoblasts underwent cyclic mechanical stretch in vitro, to explore the relationship between miRNA expression and NF-κB activation during stretch-mediated myoblast proliferation. The results revealed that 10% deformation, 0.125 Hz cyclic mechanical stretch could promote myoblast proliferation. The miRNA expression profile was subsequently altered; miR-500, −1934, −31, −378, −331 and −5097 were downregulated, whereas miR-1941 was upregulated. These miRNAs were all involved in stretch-mediated myoblast proliferation. Notably, the expression of these miRNAs was reversed following treatment of 0.125 Hz mechanically stretched C2C12 cells with NF-κB inhibitors, which was accompanied by C2C12 cell growth suppression. Therefore, the present study is the first, to the best of our knowledge, to demonstrate that the NF-κB-dependent miRNA profile is associated with mechanical stretch-induced myoblast proliferation.

Multiple Effects of Mechanical Stretch on Myogenic Progenitor Cells

“…Furthermore, they confirmed that NF-jB was essential in stretch-induced proliferation of C2C12, since transfecting the IjB (inhibitor of NF-kB) completely restrained the elevated proliferation during 1 h stretch [22]. On the other hand, the indispensable role of NF-jB in expansion of C2C12 myoblasts during longer duration of stretch (2 h/day for 2 and 4 days) was testified by using NF-jBspecific inhibitors, Pyrrolidine dithiocarbamate and BAY11-7082 [23,24].…”

“…In addition to these miRNAs, other miRNAs, such as miR500, miR1934, miR378, miR31, miR331, miR5097, and miR1941, were also reported to be regulated by mechanical stretching of C2C12 myoblasts, as we mentioned above to be downstream factors of NF-jB [24].…”

“…Similarly, another study applied the static stretch at the magnitude of 1%, 4%, and 168%, and demonstrated that myoblast proliferation was provoked by 1%, 4%, but hindered by 168% stretch [41]. Hua et al found that 10% cyclic stretch at 0.125 Hz rendered proliferation, but 0.5 Hz cyclic stretch obstructed it [24]. With regard to stretching duration, Feng et al [42] showed that C2C12 proliferated most rapidly at 4 h of cyclic stretch, whereas the proliferation rate started to attenuate after longer exposure (6 and 8 h) to stretch.…”

“…It has been shown that cyclin D1 and interleukin-6, two well-known mitogenic factors, contain NF-jB-binding sites in their promotor regions and showed increased expressions in stretched C2C12s [22]. In addition, some MicroRNAs, such as miR378, miR331, miR5097, and miR1941, were reported to be regulated by NF-kB, being candidates in modulating stretch-induced C2C12 myoblast proliferation [24].…”

MicroRNA Expression Profiling of Pancreatic Cancer Cell Line L3.6p1 Following B7-H4 Knockdown

“…In contrast, B7-H4 inhibits T-cell activation and proliferation via the inhibition of NF-kappaB nuclear translocation [33]. These transcription factors might regulate the expression of miRNAs [34, 35]. Thus, it was useful to investigate whether B7-H4 regulates the expression of miRNAs in our experimental context.…”