The metabolism of cholesterol, an essential cell membrane component and precursor in metabolic pathways, is tightly regulated at both the cellular and organismal level. Insufficient or excessive cholesterol levels result in pathologic processes, thereby necessitating a complex homeostatic regulation of cholesterol availability to cells and tissues. However, it remains poorly understood how the intricate processes of cholesterol influx and efflux are coordinately regulated to maintain cholesterol homeostasis. MicroRNAs are small endogenous RNAs that have emerged as post- transcriptional regulators of physiological processes. These short, double stranded RNAs are encoded in the genome and bind to complementary target sites in the 3'untranslated regions (3'UTR) of mRNAs, causing translational repression and/or mRNA destabilization. Notably, a single miRNA can have multiple targets, thus providing a mechanism for simultaneously regulating the post-transcriptional expression of genes involved in a specific pathway or physiological process. We hypothesize that microRNAs may play important roles in the epigenetic regulation of cholesterol metabolism gene pathways. To gain insight into role of microRNAs in cholesterol metabolism, we undertook an unbiased genome-wide screen of microRNAs modulated by cellular cholesterol content. We identified miRNAs that target components of the pathways regulating both low density lipoprotein (LDL) and high density lipoprotein (HDL). In this grant, we propose to determine the role of these microRNAs in both the physiological and pathological processes of cholesterol regulation. Specifically we will use overexpression and antagonism approaches to: (1) assess the role of these microRNAs in regulating lipoprotein metabolism, and (2) determine their impact on atherosclerosis progression and regression. These studies will provide insight into the mechanisms by which microRNAs contribute to the post-transcriptional regulation of cholesterol homeostasis, and assess their potential as therapeutic targets in the treatment of cardiovascular disease. !
Atherosclerotic vascular disease is a major health problem in the US and the western world. This project will advance our understanding of the pathways that regulate LDL and HDL cholesterol metabolism, two independent risk factors for atherosclerosis. These studies may uncover novel therapeutic strategies for the treatment of cardiovascular disease.
|Moore, Kathryn J; Fisher, Edward A (2014) High-density lipoproteins put out the fire. Cell Metab 19:175-6|
|Distel, Emilie; Barrett, Tessa J; Chung, Kellie et al. (2014) miR33 inhibition overcomes deleterious effects of diabetes mellitus on atherosclerosis plaque regression in mice. Circ Res 115:759-69|
|Rayner, Katey J; Moore, Kathryn J (2014) MicroRNA control of high-density lipoprotein metabolism and function. Circ Res 114:183-92|
|Vickers, Kasey C; Moore, Kathryn J (2013) Small RNA overcomes the challenges of therapeutic targeting of microsomal triglyceride transfer protein. Circ Res 113:1189-91|
|Moore, Kathryn J; Sheedy, Frederick J; Fisher, Edward A (2013) Macrophages in atherosclerosis: a dynamic balance. Nat Rev Immunol 13:709-21|
|Hennessy, Elizabeth J; Moore, Kathryn J (2013) Using microRNA as an alternative treatment for hyperlipidemia and cardiovascular disease: cardio-miRs in the pipeline. J Cardiovasc Pharmacol 62:247-54|
|Fernandez-Hernando, Carlos; Moore, Kathryn J (2011) MicroRNA modulation of cholesterol homeostasis. Arterioscler Thromb Vasc Biol 31:2378-82|
|Rayner, Katey J; Sheedy, Frederick J; Esau, Christine C et al. (2011) Antagonism of miR-33 in mice promotes reverse cholesterol transport and regression of atherosclerosis. J Clin Invest 121:2921-31|
|Rayner, Katey J; Esau, Christine C; Hussain, Farah N et al. (2011) Inhibition of miR-33a/b in non-human primates raises plasma HDL and lowers VLDL triglycerides. Nature 478:404-7|