Anti-fibrotic effect of melittin on TRIM47 expression in human embryonic lung fibroblast through regulating TRIM47 pathway

To investigate the effect and underlying mechanism of melittin and tripartite motif (TRIM) family in human embryonic lung fibroblast (HELF). Lentiviral RNA interference vector and lentiviral overexpression vector were constructed and packaged by transfecting 293T cells; the proliferation of HELF was examined using Cell Counting Kit 8; Western blot and qRT-PCR were performed to examine protein and mRNA expression; the interaction with protein phosphatase magnesium-dependent 1A (PPM1A) was examined by Co-immunoprecipitation. Compared with the control group, the mRNA expression of the TRIM6, TRIM8 and TRIM47 in the IPF group significantly increased. Melittin inhibited the mRNA expression and protein expression levels of TRIM47, the HELF proliferation, the hydroxyproline levels, and the phosphorylation of Smad2/3; the interference of TRIM47 inhibited the protein expression of Vimentin, α-SMA, CTGF, the phosphorylation of Smad2/3 and the synthesis of hydroxyproline; TRIM47 overexpression elevated the phosphorylation of Smad2/3, induced ubiquitination of PPM1A and decreased the expression level of PPM1A, while TRIM47 RNA interference reversed this result. Melittin has anti-fibrotic effect in HELF by directly reducing the phosphorylation of Smad2/3 or indirectly reducing the phosphorylation of Smad2/3 by decreasing the expression levels of TRIM47 whose overexpression induces ubiquitination of PPM1A.