Effect of Kruppel-like factor 6 overexpression on cholesterol accumulation in macrophages

doi:10.3969/j.issn.2095-4344.2014.51.013

Abstract

Abstract:

BACKGROUND: Recent studies have shown that Kruppel-like factor 6 (KLF6) gene is closely related to macrophage polarization. However, the role of KLF6 in the formation of macrophage foam cells is completely unknown.

OBJECTIVE: To investigate the effect of KLF6 gene on oxidized low density lipoprotein (ox-LDL)-induced cholesterol accumulation and expression of ATP binding cassette transporter A1 in RAW264.7 macrophages.

METHODS: RAW264.7 cell lines were transfected with lentiviral empty vector and recombinant vector carrying pCDH-KLF6, respectively, which acted as control group and KLF6 gene group. RAW264.7 cell lines stably transfected with lentiviral empty vector and recombinant vector carrying pCDH-KLF6 were cultured in 50 mg/L ox-LDL for 48 hours to establish ox-LDL group and ox-LDL+KLF6 group, respectively.

RESULTS AND CONCLUSION: The contents of total cholesterol and cholesterol ester in the ox-LDL group were significantly higher than those in the control group (P < 0.05) and the ox-LDL+KLF6 group (P < 0.05). In addition, the ratio of cholesterol ester to total cholesterol in the ox-LDL group was also lower in the ox-LDL+KLF6 group than the ox-LDL group (P < 0.05). However, the intracellular lipid level was lower in the control and KLF6 groups than in the two ox-LDL groups, and there was no difference between the control and KLF6 groups. These findings indicate that KLF6 can upregulate the expression of ATP binding cassette transporter A1 and inhibit the cholesterol accumulation induced by ox-LDL in RAW 264.7 macrophages．

中国组织工程研究杂志出版内容重点：组织构建；骨细胞；软骨细胞；细胞培养；成纤维细胞；血管内皮细胞；骨质疏松；组织工程

全文链接：

Key words: lipoproteins, LDL, cholesterol, macrophages, Kruppel-like transcription factors

CLC Number:

R318

Wang Hui-qing, Zhang Zong-qi, Huang Wen-hong, Wang Xiao-fei, Zhu Yan. Effect of Kruppel-like factor 6 overexpression on cholesterol accumulation in macrophages[J]. Chinese Journal of Tissue Engineering Research, 2014, 18(51): 8269-8274.

Figures/Tables 3

References

[1]Moore KJ, Tabas I. Macrophages in the pathogenesis of atherosclerosis. Cell. 2011;145(3): 341-355.
[2]Bobryshev YV. Monocyte recruitment and foam cell formation in atherosclerosis. Micron. 2006;37(3):208-222.
[3]Taghavie-Moghadam PL, Butcher MJ, Galkina EV. The dynamic lives of macrophage and dendritic cell subsets in atherosclerosis. Ann N Y Acad Sci. 2014;1319:19-37.
[4]Botham KM, Wheeler-Jones CP. Postprandial lipoproteins and the molecular regulation of vascular homeostasis. Prog Lipid Res. 2013;52(4):446-464.
[5]Imanishi T, Akasaka T. Novel strategies to target inflammatory processes in atherosclerosis. Curr Pharm Des. 2013;19(9): 1616-1625.
[6]Webb NR, Moore KJ. Macrophage-derived foam cells in atherosclerosis: lessons from murine models and implications for therapy. Curr Drug Targets. 2007;8(12):1249-1263.
[7]Fernández-Velasco M, González-Ramos S, Boscá L. Involvement of monocytes/macrophages as key factors in the development and progression of cardiovascular diseases. Biochem J. 2014;458(2):187-193.
[8]Gui T, Shimokado A, Sun Y, et al. Diverse roles of macrophages in atherosclerosis: from inflammatory biology to biomarker discovery. Mediators Inflamm. 2012;2012:693083.
[9]Yuan Y, Li P, Ye J. Lipid homeostasis and the formation of macrophage-derived foam cells in atherosclerosis. Protein Cell. 2012;3(3):173-181.
[10]Andreoli V, Gehrau RC, Bocco JL. Biology of Krüppel-like factor 6 transcriptional regulator in cell life and death. IUBMB Life. 2010;62(12):896-905.
[11]Zhang Y, Lei CQ, Hu YH, et al. Krüppel-like factor 6 is a co-activator of NF-κB that mediates p65-dependent transcription of selected downstream genes. J Biol Chem. 2014;289(18):12876-12885.
[12]Qi W, Holian J, Tan CY, et al. The roles of Kruppel-like factor 6 and peroxisome proliferator-activated receptor-γ in the regulation of macrophage inflammatory protein-3α at early onset of diabetes. Int J Biochem Cell Biol. 2011;43(3): 383-392.
[13]Duan SZ, Usher MG, Mortensen RM. Peroxisome proliferator-activated receptor-gamma-mediated effects in the vasculature. Circ Res. 2008;102(3):283-294.
[14]Mao Z, Ong AC. Peroxisome proliferator-activated receptor gamma agonists in kidney disease--future promise, present fears. Nephron Clin Pract. 2009;112(4):c230-241.
[15]Ketsawatsomkron P, Pelham CJ, Groh S, et al. Does peroxisome proliferator-activated receptor-gamma (PPAR gamma) protect from hypertension directly through effects in the vasculature? J Biol Chem. 2010;285(13):9311-9316.
[16]Chen YC, Wu JS, Tsai HD, et al. Peroxisome proliferator-activated receptor gamma (PPAR-γ) and neurodegenerative disorders. Mol Neurobiol. 2012;46(1): 114-124.
[17]Freitag CM, Miller RJ. Peroxisome proliferator-activated receptor agonists modulate neuropathic pain: a link to chemokines? Front Cell Neurosci. 2014;8:238.
[18]Yang J, Zhou Y, Guan Y. PPARγ as a therapeutic target in diabetic nephropathy and other renal diseases. Curr Opin Nephrol Hypertens. 2012;21(1):97-105.
[19]Date D, Das R, Narla G, et al. Kruppel-like transcription factor 6 regulates inflammatory macrophage polarization. J Biol Chem. 2014;289(15):10318-10329.
[20]Steinberg D. Modified forms of low-density lipoprotein and atherosclerosis. J Intern Med. 1993;233(3):227-232.
[21]Lei L, Xiong Y, Chen J, et al. TNF-alpha stimulates the ACAT1 expression in differentiating monocytes to promote the CE-laden cell formation. J Lipid Res. 2009;50(6): 1057-1067.
[22]Luo ZF, Feng B, Mu J, et al. Effects of 4-phenylbutyric acid on the process and development of diabetic nephropathy induced in rats by streptozotocin: regulation of endoplasmic reticulum stress-oxidative activation. Toxicol Appl Pharmacol. 2010;246(1-2):49-57.
[23]Glass CK, Witztum JL. Atherosclerosis. the road ahead. Cell. 2001;104(4):503-516.
[24]Hansson GK. Inflammation, atherosclerosis, and coronary artery disease. N Engl J Med. 2005;352(16):1685-1695.
[25]Mehta JL, Saldeen TG, Rand K. Interactive role of infection, inflammation and traditional risk factors in atherosclerosis and coronary artery disease. J Am Coll Cardiol. 1998;31(6): 1217-1225.
[26]Steinberg D. Hypercholesterolemia and inflammation in atherogenesis: two sides of the same coin. Mol Nutr Food Res. 2005;49(11):995-998.
[27]Malkin CJ, Pugh PJ, Jones RD, et al. Testosterone as a protective factor against atherosclerosis--immunomodulation and influence upon plaque development and stability. J Endocrinol. 2003;178(3):373-380.
[28]George JF, Pinderski LJ, Litovsky S, et al. Of mice and men: mouse models and the molecular mechanisms of post-transplant coronary artery disease. J Heart Lung Transplant. 2005;24(12):2003-2014.
[29]Li JJ. Inflammation: an important mechanism for different clinical entities of coronary artery diseases. Chin Med J (Engl). 2005;118(21):1817-1826.
[30]O'Kelly BF, Massie BM, Tubau JF, et al. Coronary morbidity and mortality, pre-existing silent coronary artery disease, and mild hypertension. Ann Intern Med. 1989;110(12):1017-1026.
[31]Bellosta S, Bernini F, Chinetti G, et al. Macrophage function and stability of the atherosclerotic plaque: progress report of a European project. Nutr Metab Cardiovasc Dis. 2002;12(1): 3-11.
[32]Granada JF, Kaluza GL, Wilensky RL, et al. Porcine models of coronary atherosclerosis and vulnerable plaque for imaging and interventional research. EuroIntervention. 2009;5(1): 140-148.
[33]Li AC, Glass CK. The macrophage foam cell as a target for therapeutic intervention. Nat Med. 2002;8(11):1235-1242.
[34]Hansson GK, Libby P. The immune response in atherosclerosis: a double-edged sword. Nat Rev Immunol. 2006;6(7):508-519.
[35]Hansson GK, Nilsson J. Vaccination against atherosclerosis? Induction of atheroprotective immunity. Semin Immunopathol. 2009;31(1):95-101.
[36]Nilsson J, Nordin Fredrikson G, Schiopu A, et al. Oxidized LDL antibodies in treatment and risk assessment of atherosclerosis and associated cardiovascular disease. Curr Pharm Des. 2007;13(10):1021-1030.
[37]Loppnow H, Werdan K, Buerke M. Vascular cells contribute to atherosclerosis by cytokine- and innate-immunity-related inflammatory mechanisms. Innate Immun. 2008;14(2):63-87.
[38]Meier P, Meier R, Blanc E. Influence of CD4+/CD25+ regulatory T cells on atherogenesis in patients with end-stage kidney disease. Expert Rev Cardiovasc Ther. 2008;6(7): 987-997.
[39]Gibson FC 3rd, Ukai T, Genco CA. Engagement of specific innate immune signaling pathways during Porphyromonas gingivalis induced chronic inflammation and atherosclerosis. Front Biosci. 2008;13:2041-2059.
[40]Nilsson J, Fredrikson GN, Björkbacka H, et al. Vaccines modulating lipoprotein autoimmunity as a possible future therapy for cardiovascular disease. J Intern Med. 2009;266(3): 221-231.
[41]Bechmann LP, Vetter D, Ishida J, et al. Post-transcriptional activation of PPAR alpha by KLF6 in hepatic steatosis. J Hepatol. 2013;58(5):1000-1006.
[42]Narla G, Friedman SL, Martignetti JA. Krüppel cripples prostate cancer: KLF6 progress and prospects. Am J Pathol. 2003;162(4):1047-1052.
[43]Weber U, Rodriguez E, Martignetti J, et al. Luna, a Drosophila KLF6/KLF7, is maternally required for synchronized nuclear and centrosome cycles in the preblastoderm embryo. PLoS One. 2014;9(6):e96933.
[44]Ozdemir F, Koksal M, Ozmen V, et al. Mutations and Krüppel-like factor 6 (KLF6) expression levels in breast cancer. Tumour Biol. 2014;35(6):5219-5225.
[45]Das H, Kumar A, Lin Z, et al. Kruppel-like factor 2 (KLF2) regulates proinflammatory activation of monocytes. Proc Natl Acad Sci U S A. 2006;103(17):6653-6658.
[46]Nayak L, Goduni L, Takami Y, et al. Kruppel-like factor 2 is a transcriptional regulator of chronic and acute inflammation. Am J Pathol. 2013;182(5):1696-1704.
[47]Feinberg MW, Cao Z, Wara AK, et al. Kruppel-like factor 4 is a mediator of proinflammatory signaling in macrophages. J Biol Chem. 2005;280(46):38247-38258.
[48]Liao X, Sharma N, Kapadia F, et al. Krüppel-like factor 4 regulates macrophage polarization. J Clin Invest. 2011;121(7): 2736-2749.
[49]Joyce CW, Amar MJ, Lambert G, et al. The ATP binding cassette transporter A1 (ABCA1) modulates the development of aortic atherosclerosis in C57BL/6 and apoE-knockout mice. Proc Natl Acad Sci U S A. 2002;99(1):407-412.
[50]Westerterp M, Murphy AJ, Wang M, et al. Deficiency of ATP-binding cassette transporters A1 and G1 in macrophages increases inflammation and accelerates atherosclerosis in mice. Circ Res. 2013;112(11):1456-1465.
[51]Chen X, Zhao Y, Guo Z, et al. Transcriptional regulation of ATP-binding cassette transporter A1 expression by a novel signaling pathway. J Biol Chem. 2011;286(11):8917-8923.
[52]Chawla A, Boisvert WA, Lee CH, et al. A PPAR gamma-LXR-ABCA1 pathway in macrophages is involved in cholesterol efflux and atherogenesis. Mol Cell. 2001;7(1): 161-171.