Oxidized low density lipoprotein combined with influenza virus induced macrophages apoptosis by aggravating endoplasmic reticulum stress

Abstract

Objective To investigate the effect and underlying mechanism of influenza virus infection in macrophages especially in low oxidized density lipoprotein (oxLDL) mimicked high lipid conditions.Methods Cell viability and apoptosis were detected by MTT assay and flow cytometry when macrophages were infected by different concentrations of influenza virus for 8 h,24 h and 48 h in the presence or absence of oxLDL.The expressions of GRP78,GADD153 mRNA were detected by RT-PCR and Western blot analysis.Results ①Influenza virus could infect THP-1 macrophages and induce cell apoptosis.②Low level oxLDL(＜ 5 μg/mL)promoted cell survival,in contrast,high level oxLDL (＞ 10 μg/mL)promoted cell apoptosis.③OxLDL pretreatment at 5 μg/mL did not influence macrophage apoptosis sole (P =0.159),on the contrary,it increased macrophages apoptosis along with different concentrations (1 × 103,2 × 103,5 × 103 and 1 × 104TCID50/mL) of influenza virus infection.The P values were 0.001,0.001,0.026 and 0.035,respectively.④The expressions of GRP78 and GADD153 related to endoplasmic reticulum stress were significantly inclined compared with oxLDL absence groups in influenza virus infected conditions.Conclusions Endoplasmic reticulum stress plays a role in oxLDL pretreatment to promote influenza virus infection induced macrophages apoptosis. Key words: Oxidized low density lipoprotein ; Influenza virus ; GADD153 ; Macrophage