Nuclear receptor Nur77 inhibits oxidized low density lipoprotein induced lipid loading in macrophages / 中华心血管病杂志

<p><b>OBJECTIVE</b>To observe the effect of Nur77 on lipid loading in macrophages exposed to 40 microg/ml oxidized low density lipoprotein (ox-LDL).</p><p><b>METHODS</b>Stable RAW264.7 strain expressing green fluorescent protein (GFP) or GFP-Nur77 was established by G418 screening after transfection with corresponding plasmids and identified by Western blot. After 24 h stimulation with ox-LDL, intracellular lipid loading of each strain was observed by Oil Red O dyeing, and the intracellular cholesterol level was measured by liquid chromatographic-mass spectrometry (LC-MS). The transcriptional changes of CD36 and ABCA1 were monitored by Real Time Quantitative-PCR, while the expressions of these two proteins were assayed by flow cytometry and Western blot, respectively.</p><p><b>RESULTS</b>After 24 h stimulation with ox-LDL, intracellular total cholesterol and esterified cholesterol concentration in GFP-Nur77-RAW264.7 were significantly dropped by 26.15% and 30.93% respectively (P < 0.05 vs. GFP-RAW264.7). The transcription and expression of ABCA1 in GFP-Nur77-RAW264.7 were significantly increased while the transcription and expression of CD36 were significantly reduced (all P < 0.05 vs. GFP-RAW264.7).</p><p><b>CONCLUSION</b>Orphan nuclear receptor Nur77 reduced ox-LDL induced intracellular lipid loading in macrophages by inhibiting lipid influx and enhancing lipid efflux.</p>

Effect of retinoid X receptor activation on oxidized low-density lipoprotein induced cell differentiation of murine macrophage cell line into dendritic like cells / 中华心血管病杂志

<p><b>OBJECTIVE</b>To investigate the effect and related mechanism of retinoid X receptor (RXR) activation on oxidized low-density lipoprotein (ox-LDL) induced differentiation of macrophage into dendritic cell.</p><p><b>METHODS</b>RAW264.7 murine macrophage cell line was cultured with ox-LDL for 48 h in the absence and presence of RXR activator 9-cisRA or SR11237. Cell morphology was observed by phase contrast microscope and cell surface markers involved in dendritic cell immune maturation and activation was analyzed by FACS. Cellular reactive oxygen species production was detected by CM-H2DCFDA fluorescent probe.</p><p><b>RESULTS</b>ox-LDL-treated RAW264.7 murine macrophage cell line differentiated into dendritic like cells after 48 h and cell surface markers CD40, CD86, CD83, MHC Class II and CD1d were upregulated. These changes could be attenuated by cotreatment with 9-cisRA or SR11237. Upregulated cell surface markers CD40, CD86, CD83, MHC Class II and CD1d by ox-LDL were decreased about 47%, 43%, 48%, 32% and 17% respectively by 9-cisRA and 38%, 38%, 46%, 36% and 32% respectively by SR11237. The effect of 9-cisRA and SR11237 was dose dependent. Cellular reactive oxygen species were significantly increased in ox-LDL-treated RAW264.7 cells (MFI 38.24 +/- 4.20 vs. 4.46 +/- 0.39, P < 0.05) and which was significantly reduced by 9-cisRA (10(-7) mol/L) and SR11237 (10(-6) mol/L) to 12.60 +/- 1.52 and 17.89 +/- 1.91 respectively (all P < 0.05).</p><p><b>CONCLUSION</b>RXR activation partly inhibits the differentiation of ox-LDL induced macrophage into dendritic cell by reducing oxidative stress injury.</p>