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Updated: May 15, 2026
Using Human Induced Pluripotent Stem Cell-derived Hepatocyte-like Cells for Drug Discovery
Published on: May 19, 2018
Genome-wide screen for modulation of hepatic apolipoprotein A-I (ApoA-I) secretion
Rebecca R Miles1, William Perry, Joseph V Haas
1Lilly Research Laboratories, Eli Lilly and Company, Indianapolis, Indiana 46285, USA.
Insights
Researchers identified new therapeutic targets for coronary artery disease by screening genes that regulate apolipoprotein A-I (ApoA-I) secretion. This approach identified farnesyltransferase (FNTA) as a target that, when repressed, increases ApoA-I levels, a key component of HDL cholesterol.
Area of Science:
- Genetics and Genomics
- Cardiovascular Disease Research
- Drug Discovery
Background:
- Elevated LDL cholesterol is a primary target for coronary artery disease (CAD) management, yet only offers partial risk reduction.
- Low HDL cholesterol (HDL-c) is an independent risk factor for CAD.
- Apolipoprotein A-I (ApoA-I), the main HDL protein, is crucial for reverse cholesterol transport; increasing ApoA-I is a promising strategy for CAD.
Purpose of the Study:
- To identify novel genetic targets regulating hepatocyte secretion of ApoA-I.
- To explore new therapeutic strategies for increasing HDL cholesterol and managing CAD.
- To leverage functional genetic screening for identifying druggable targets.
Main Methods:
- Genome-wide siRNA screening of 21,789 siRNAs in hepatocytes to identify genes affecting ApoA-I secretion.
- Triage of initial hits (approx. 800 genes) using genetic associations, gene expression, druggability, and pathway analysis.
- Confirmation of 40 key genes, including functional validation of farnesyltransferase (FNTA) repression.
Main Results:
- Identification and validation of 40 genes that regulate hepatocyte ApoA-I secretion.
- Repression of FNTA using siRNA or manumycin A significantly increased ApoA-I secretion in hepatocytes.
- Elevated ApoA-I secretion was also observed in transgenic mice models following FNTA repression.
Conclusions:
- Functional genetic screening is a powerful approach for discovering novel therapeutic targets for cardiovascular diseases.
- FNTA is identified as a novel target that can modulate ApoA-I secretion, offering a potential strategy for increasing HDL-c.
- This study provides a foundation for developing new therapies aimed at improving cholesterol management and reducing CAD risk.
Abstract:
Control of plasma cholesterol levels is a major therapeutic strategy for management of coronary artery disease (CAD). Although reducing LDL cholesterol (LDL-c) levels decreases morbidity and mortality, this therapeutic intervention only translates into a 25-40% reduction in cardiovascular events. Epidemiological studies have shown that a high LDL-c level is not the only risk factor for CAD; low HDL cholesterol (HDL-c) is an independent risk factor for CAD. Apolipoprotein A-I (ApoA-I) is the major protein component of HDL-c that mediates reverse cholesterol transport from tissues to the liver for excretion. Therefore, increasing ApoA-I levels is an attractive strategy for HDL-c elevation. Using genome-wide siRNA screening, targets that regulate hepatocyte ApoA-I secretion were identified through transfection of 21,789 siRNAs into hepatocytes whereby cell supernatants were assayed for ApoA-I. Approximately 800 genes were identified and triaged using a convergence of information, including genetic associations with HDL-c levels, tissue-specific gene expression, druggability assessments, and pathway analysis. Fifty-nine genes were selected for reconfirmation; 40 genes were confirmed. Here we describe the siRNA screening strategy, assay implementation and validation, data triaging, and example genes of interest. The genes of interest include known and novel genes encoding secreted enzymes, proteases, G-protein-coupled receptors, metabolic enzymes, ion transporters, and proteins of unknown function. Repression of farnesyltransferase (FNTA) by siRNA and the enzyme inhibitor manumycin A caused elevation of ApoA-I secretion from hepatocytes and from transgenic mice expressing hApoA-I and cholesterol ester transfer protein transgenes. In total, this work underscores the power of functional genetic assessment to identify new therapeutic targets.
