Identification of human microRNAs modulating ApoB and ApoAI secretion

Project: Research

Investigators

  • Liye Zhou (PI)

Description

Cardiovascular diseases (CVD) are the major causes of morbidity and mortality in the western world. High plasma LDL and low HDL are risk factors of CVD. Therefore, therapeutic agents that decrease LDL and increase HDL would be ideal treatment modalities. Our laboratory has previously identified microRNA 30c (miR-30c) that reduces LDL and atherosclerosis in hyperlipidemic mice (1). MiRs are small non-coding RNAs (~22nt) that target multiple mRNAs to modulate diverse biological pathways. I reasoned that there must be some miRs to be discovered that could simultaneously lower LDL and increase HDL. Such miRs would be useful for the treatment of hyperlipidemia and CVD. To test this prospect, I screened a library of 1237 human miRs and identified three miRs that decreased apoB (LDL scaffolding protein) and increased apoAI (major HDL protein) secretion from Huh7 human hepatoma cells. I am proposing to find out how the most potent miR-1200 reduces apoB and increases apoAI and to determine whether it can reduce hyperlipidemia and atherosclerosis.Aim 1: How does miR-1200 decrease LDL and increase HDL? Aim 1A: Identify mechanisms decreasing apoB secretion: Bioinformatics approaches revealed that miR-1200 might target apoB and MTP mRNAs. Therefore, I hypothesize that miR-1200 reduces apoB secretion by interacting with the 3'-untranslated regions (3'-UTR) of apoB and MTP mRNAs. I will (1) measure changes in apoB and MTP mRNA in cells transfected with miR-1200 or Scr; (2) determine whether miR-1200 affects mRNA levels via transcriptional or posttranscriptional mechanisms; and (3) ask whether 'seed' and 'supplementary' interactions between miR-1200 and these mRNAs are important for the regulation of mRNA levels. These studies will show that miR-1200 interacts with apoB and MTP mRNA to induce degradation, and reduces apoB secretion. Aim1B: Demonstrate the effects of miR-1200 on de novo lipogenesis: Multiple genes in hepatic lipid synthesis pathway such as SCL25A1 are predicted as potential targets of miR-1200. So, I hypothesize that reductions in the expression of these genes will reduce de novo lipogenesis. Such reductions may avoid steatosis anticipated as a consequence of reductions in lipoprotein secretion. Aim 1C: Explain mechanisms increasing apoAI secretion: Bioinformatics analyses suggest that miR-1200 does not target apoAI or ABCA1 mRNAs. My preliminary studies showed that miR-1200 increases apoAI mRNA. Therefore, I hypothesize that miR-1200 reduces the express
Award amount$46,000.00
Award date07/01/2015
Program typePredoctoral Fellowship
Award ID15PRE25730045
Effective start/end date07/01/201506/30/2017
StatusFinished