Inhibitory effect of PCSK9 on Abca1 protein expression and cholesterol efflux in macrophages

Endothelial ABCA1 expression protects against atherosclerosis and this atheroprotective effect is partially attributed to enhancing apoAI-mediated cholesterol efflux. ABCA1 is a target gene for LXR and RXR; therefore, treating endothelial cells with LXR and/or RXR agonists may increase ABCA1 expression. We tested whether treating cultured immortalized mouse aortic endothelial cells (iMAEC) with the endogenous LXR agonist 22(R)-hydroxycholesterol, synthetic LXR agonist GW3965, endogenous RXR agonist 9-cis-retinoic acid, or synthetic RXR agonist SR11237 increases ABCA1 protein expression. We observed a significant increase in ABCA1 protein expression in iMAEC treated with either GW3965 or SR11237 alone, but no significant increase in ABCA1 protein was observed in iMAEC treated with either 22(R)-hydroxycholesterol or 9-cis-retionic acid alone. However, we observed significant increases in both ABCA1 protein expression and apoAI-mediated cholesterol efflux when iMAEC were treated with a combination of either 22(R)-hydroxycholesterol and 9-cis-retinoic acid or GW3965 and SR11237. Furthermore, treating iMAEC with either 22(R)-hydroxycholesterol and 9-cis-retinoic acid or GW3965 and SR11237 did not trigger an inflammatory response, based on VCAM-1, ICAM-1, CCL2, and IL-6 mRNA expression. Based on our findings, delivering LXR and RXR agonists precisely to endothelial cells may be a promising atheroprotective approach.

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The silencing of long non-coding RNA ANRIL suppresses invasion, and promotes apoptosis of retinoblastoma cells through the ATM-E2F1 signaling pathway

Bioscience Reports ◽

10.1042/bsr20180558 ◽

2018 ◽

Vol 38 (6) ◽

Cited By ~ 8

Author(s):

Yang Yang ◽

Xiao-Wei Peng

Keyword(s):

Protein Expression ◽

Signaling Pathway ◽

Inhibitory Effect ◽

Down Regulation ◽

Reading Frame ◽

Non Coding Rna ◽

Retinoblastoma Cells ◽

Human Retinoblastoma ◽

Y79 Cells ◽

Long Non Coding Rna

As one of the most common primary intraocular carcinomas, retinoblastoma generally stems from the inactivation of the retinoblastoma RB1 gene in retinal cells. Antisense non-coding RNA in the INK4 locus (ANRIL), a long non-coding RNA (lncRNA), has been reported to affect tumorigenesis and progression of various cancers, including gastric cancer and non-small cell lung cancer. However, limited investigations emphasized the role of ANRIL in human retinoblastoma. Hence, the current study was intended to investigate the effects of ANRIL on the proliferation, apoptosis, and invasion of retinoblastoma HXO-RB44 and Y79 cells. The lentivirus-based packaging system was designed to aid the up-regulation of ANRIL and ATM expressions or employed for the down-regulation of ANRIL in human retinoblastoma cells. Afterward, ANRIL expression, mRNA and protein expression of ATM and E2F1, and protein expression of INK4b, INK4a, alternate reading frame (ARF), p53 and retinoblastoma protein (pRB) were determined in order to elucidate the regulation effect associated with ANRIL on the ATM-E2F1 signaling pathway. In addition, cell viability, apoptosis, and invasion were detected accordingly. The results indicated that the down-regulation of ANRIL or up-regulation of ATM led to an increase in the expressions of ATM, E2F1, INK4b, INK4a, ARF, p53, and pRB. The silencing of ANRIL or up-regulation of ATM exerted an inhibitory effect on the proliferation and invasion while improving the apoptosis of HXO-RB44 and Y79 cells. In conclusion, the key observations of our study demonstrated that ANRIL depletion could act to suppress retinoblastoma progression by activating the ATM-E2F1 signaling pathway. These results provide a potentially promising basis for the targetted intervention treatment of human retinoblastoma.

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Effect of Apolipoprotein A-I on ATP Binding Cassette Transporter A1 Degradation and Cholesterol Efflux in THP-1 Macrophage-derived Foam Cells

Acta Biochimica et Biophysica Sinica ◽

10.1093/abbs/36.3.218 ◽

2004 ◽

Vol 36 (3) ◽

pp. 218-226 ◽

Cited By ~ 26

Author(s):

Chao-Ke Tang ◽

Guo-Hua Tang ◽

Guang-Hui Yi ◽

Zuo Wang ◽

Lu-Shan Liu ◽

...

Keyword(s):

Protease Inhibitors ◽

Cholesterol Efflux ◽

Foam Cells ◽

Atp Binding ◽

Thiol Protease ◽

Atp Binding Cassette Transporter ◽

Apolipoprotein A ◽

Abca1 Protein ◽

Abca1 Mrna ◽

Atp Binding Cassette

Abstract Cholesterol-loaded macrophage foam cells are a central component of atherosclerotic lesions. ATP binding cassette transporter A1 (ABCA1), the defective molecule in Tangier disease, mediates the efflux of phospholipid and cholesterol from cells to apolipoprotein A-I (apoA-I), reversing foam cell formation. This study investigated the effect of apoA-I on ABCA1 degradation and cholesterol efflux in THP-1 macrophage-derived foam cells. After exposure of the cultured THP-1 macrophage-derived foam cells to apoA-I for different time, cholesterol efflux, ABCA1 mRNA and protein levels were determined by FJ-2107P type liquid scintillator, RT-PCR and Western blot, respectively. The mean ABCA1 fluorescence intensity on THP-1 macrophage-derived foam cells was detected by flow cytometry. Results showed that apoA-I markedly increased ABCA1-mediated cholesterol efflux from THP-1 macrophage-derived foam cells. This was accompanied by an increase in the content of ABCA1. ApoA-I did not alter ABCA1 mRNA abundance. Significantly, thiol protease inhibitors increased the level of ABCA1 protein and slowed its decay in THP-1 macrophage-derived foam cells, whereas none of the proteosome-specific inhibitor lactacystin, other protease inhibitors, or the lysosomal inhibitor NH4Cl showed such effects. The apoA-I-mediated cellular cholesterol efflux was enhanced by thiol protease inhibitors. Our results suggested that thiol protease inhibitors might provide an alternative way to upregulate ABCA1 protein. This strategy is especially appealing since it may mimic the stabilizing effect of the natural ligands apoA-I.

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Abstract 616: Interleukin 22 Downregulates ABCG1 and Impairs Cholesterol Efflux in Macrophages

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/atvb.34.suppl_1.616 ◽

2014 ◽

Vol 34 (suppl_1) ◽

Author(s):

Marion Hofmann Bowman ◽

Bijoy Chellan ◽

Ling Yan ◽

Timothy Sonntag ◽

Catherine Reardon

Keyword(s):

Protein Expression ◽

Barrier Function ◽

Cholesterol Efflux ◽

Peritoneal Macrophages ◽

Mouse Serum ◽

Epithelial Barrier ◽

Dependent Manner ◽

Epithelial Barrier Function ◽

Cholesterol Uptake ◽

Mrna And Protein Expression

IL22 belongs to the IL10 cytokine family and is expressed by T helper cells. IL22 functions on epithelial cells and has been shown to improve epithelial barrier function in inflammatory bowel disease, asthma, and psoriasis; autoimmune diseases associated with elevated serum IL22. Patients with psoriasis have increased coronary artery disease and it was previously shown that macrophages from patients with psoriasis have impaired cholesterol efflux. The function of IL-22 on macrophage cholesterol metabolism is not known. Methods: ABCA1, ABCG1 and CD36 mRNA and protein expression, cholesterol uptake and efflux were studied in murine macrophages and human THP-1 macrophages. C57BL6/J mice with transgenic expression of hS100A12 and hS100A8/9 in myeloid cells were generated by using a bacterial artificial chromosome (hBAC/S100 mice). hBAC/S100 and WT littermate mice were breed into mice lacking the receptor for advanced glycation endproducts, RAGE. Results: Peritoneal macrophages from hBAC/S100 mice have reduced ABCG1 mRNA and protein expression, increased cholesterol uptake, and reduced cholesterol efflux compared to WT. This was abolished in hBAC/S100 mice lacking RAGE, the receptor for S100/calgranulin. Recombinant S100A12 or S100A8 protein (2.5 μg/ml) had no effect on ABCG1 expression in WT peritoneal macrophages or human THP-1 cells, suggesting other systemic intermediary products in hBAC/S100 mice. Serum IL22 and mRNA in splenic T cells were significantly increased in hBAC/S100 mice, and this was abolished in hBAC/S100 mice lacking RAGE. Moreover, r S100A12 increased IL22 mRNA by 2-fold in cultured human THP-1. Importantly, THP-1 macrophages treated with r IL22 (100 ng/ml) had reduced expression of ABCG1 and impaired cholesterol efflux to mouse serum, but not to Apoa1. Up regulation of ABCG1 and ABCA1 in response to LXR agonist TO901317 in THP-1 cells abolished the detrimental effects of IL22 on cholesterol efflux. Conclusion: S100/calgranulin induces IL22 in a RAGE dependent manner. IL22 down regulates ABCG1 and impairs cholesterol efflux in macrophages. This raises the hypothesis that IL22-mediated down regulation of cellular cholesterol efflux may be linked to improved epithelial barrier function, but may also augment atherosclerosis.

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Inhibitory Effect of Sambucus sieboldiana var. pendula (Nakai) Extract on the mRNA and Protein Expression of iNOS and COX-2 in Raw 264.7 Cells

Microbiology and Biotechnology Letters ◽

10.4014/mbl.1704.04002 ◽

2017 ◽

Vol 45 (2) ◽

pp. 178-183 ◽

Cited By ~ 1

Author(s):

jin-Young Lee ◽

Dan-Hee Yoo ◽

Jung-Woo Chae

Keyword(s):

Protein Expression ◽

Inhibitory Effect ◽

Raw 264.7 Cells ◽

Raw 264.7 ◽

Mrna And Protein Expression ◽

Cox 2

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L-securinine inhibits cell growth and metastasis of human androgen-independent prostate cancer DU145 cells via regulating mitochondrial and AGTR1/MEK/ERK/STAT3/PAX2 apoptotic pathways

Bioscience Reports ◽

10.1042/bsr20190469 ◽

2019 ◽

Vol 39 (5) ◽

Cited By ~ 5

Author(s):

Dongxu Zhang ◽

Houxian Liu ◽

Binbin Yang ◽

Jiasheng Hu ◽

Yue Cheng

Keyword(s):

Prostate Cancer ◽

Protein Expression ◽

Annexin V ◽

Inhibitory Effect ◽

Apoptotic Pathway ◽

Growth Inhibitory ◽

Du145 Cells ◽

Apoptotic Pathways ◽

Induced Apoptosis ◽

Androgen Independent

Abstract The present study aims to evaluate the anticancer effect of L-securinine on androgen-independent prostate cancer (AIPC) DU145 cells. L-securinine (2.5, 5, and 10 μM) treatment for 24, 48 and 72 h displayed strong growth inhibitory effect on DU145 cells in a concentration and time-dependent fashion but has less toxicity toward normal androgen-dependent LNCaP cells. Hoechst 332582 staining of DU145 cells and Annexin V-FITC/ PI dual-labeling followed by flow cytometry assay identified that this growth inhibition by L-securinine would be due to the induction of apoptosis. Moreover Transwell assay revealed that L-securinine significantly inhibited the cell migration/invasion ability of DU145 cells. Furthermore, results of western blotting showed that the involvement of mitochondrial apoptotic pathway in the L-securinine-induced apoptosis of DU145 cell, as evidenced by an increase in the protein expression of Bax, cleaved caspase-9, cleaved caspase-3, cytosolic cytochrome c, and cleaved PARP, together with a unchanged cleaved caspase-8 and decreased Bcl-2 protein expression. Also, L-securinine-induced antimetastatic activity in DU145 cells was associated with decreased protein expression of MMP-2 and MMP-9 and concurrent reduction of VEGF. In addition, further studies revealed that L-securinine may inhibit the protein expression of AGTR1, p-MEK1/2, p-ERK1/2, p-STAT3, PAX2, and p-PAX2, while the expression of ERK1/2, MEK1/2, and STAT3 protein retains intact. These findings suggest that L-securinine may be a promising chemopreventive agent against AIPC.

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