IGF-1R,p-ERK is involved in LDLs-induced mouse peritoneal macrophage survival

AIM: To study the effects of low density lipoproteins (LDLs) on insulin-like growth factor-1 receptor (IGF-1R), phosphorylated extracellular signal-regulated kinase (p-ERK), Bcl-2 and Bax protein expression in mouse peritoneal macrophages (MPMs). METHODS: Using the methods of immunocytochemistry and Western blotting, the expression of IGF-1R, p-ERK, Bcl-2 and Bax protein in MPMs treated with LDLs, anti-IGF-1R antibody (α-IR-3) or ERK inhibitor (PD98059) were detected. RESULTS: oxLDL significantly increased the IGF-1R protein expression in a dose and time-dependent manner. P-ERK protein expression induced by oxLDL peaked at 5 min. Moreover, oxLDL could induced ERK translocation from cytoplasm to nuclear. When given α-IR-3, p-ERK protein expression was significantly inhibited, and ERK translocation disappeared. oxLDL increased Bcl-2 protein expression and reduced Bax expression in a dose and time-dependent manner. When given PD98059, Bcl-2 and Bax protein expression induced by oxLDL altered significantly. Native LDL had no significant effect on the expression of these four proteins. CONCLUSIONS: oxLDL may promote cultured MPMs survival at least by enhancing IGF-1R expression and ERK phosphorylation, and there may be many pathways involved in MPMs survival induced by oxLDL, Whereas native LDL had no effects on culture MPMs.