Analysis of differential gene expression by RNA-seq data in ABCG1 knockout mice.

AIMS: The previous studies on ABCG1 using genetically modified mice showed inconsistent results on atherosclerosis. The aim of this study was to determine whether accurate target knockout of ABCG1 would result in transcriptional changes of other atherosclerosis-related genes. METHODS: ABCG1 knockout mouse model was obtained by precise gene targeting without affecting non-target DNA sequences in C57BL/6 background. The wildtype C57BL/6 mice were regarded as control group. 12-week-old male mice were used in current study. We performed whole transcriptome analysis on the peripheral blood mononuclear cells obtained from ABCG1 knockout mice (n = 3) and their wildtype controls (n = 3) by RNA-seq. RESULTS: Compared with wildtype group, 605 genes were modified at the time of ABCG1 knockout and expressed differentially in knockout group, including 306 up-regulated genes and 299 down-regulated genes. 54 genes were associated with metabolism regulation, of which 13 were related to lipid metabolism. We also found some other modified genes in knockout mice involved in cell adhesion, leukocyte transendothelial migration and apoptosis, which might also play roles in the process of atherosclerosis. 7 significantly enriched GO terms and 19 significantly enriched KEGG pathways were identified, involving fatty acid biosynthesis, immune response and intracellular signal transduction. CONCLUSIONS: ABCG1 knockout mice exhibited an altered expression of multiple genes related to many aspects of atherosclerosis, which might affect the further studies to insight into the effect of ABCG1 on atherosclerosis with this animal model.

The Acute Effects of Cigarette Smoking on the Functional State of High Density Lipoprotein.

BACKGROUND: Cigarette smoking disturbs plasma lipid level and lipoprotein metabolism; however, the effects of smoking on the functional state of high density lipoprotein (HDL) are still not clear. This study aimed to determine the antioxidant and antichemotactic properties of HDL and HDL-mediated cholesterol efflux in healthy subjects after cigarette smoking. MATERIALS AND METHODS: Healthy male subjects, including nonsmokers (n = 16) and chronic smokers (n = 8), were enrolled. After smoking 8 cigarettes within 2 hours, plasma HDL was isolated and tested. Copper-induced low density lipoprotein (LDL) oxidation was used to determine the antioxidant ability of HDL. The concentration of serum amyloid A was measured by Enzyme Linked Immunosorbent Assay. Chemotaxis was detected by transwell assay. HDL-mediated cholesterol efflux was measured using fluorescent cholesterol analog. RESULTS: LDL baseline oxidation state was higher in chronic smokers than that in nonsmokers. Meanwhile, HDL-induced cholesterol efflux in macrophages in chronic smokers was significantly enhanced compared with that in nonsmokers. After acute smoking, both the antioxidant and antichemotactic ability of HDL declined in nonsmokers. However, in healthy chronic smokers, the effect of HDL on the susceptibility of LDL to oxidation was compensatorily enhanced. Nevertheless, their bodies were still in a higher oxidation state. Also, acute smoking did not affect HDL-mediated cholesterol efflux significantly in both nonsmokers and chronic smokers. CONCLUSIONS: Our data suggest that acute smoking attenuates the antioxidant and antichemotactic abilities of HDL in nonsmokers. Chronic smokers are in a higher oxidative state, although the antioxidant function of their HDL is compensatorily enhanced.