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Updated: May 17, 2026
LDL Cholesterol Uptake Assay Using Live Cell Imaging Analysis with Cell Health Monitoring
Published on: November 17, 2018
Thyroid hormone receptor agonists reduce serum cholesterol independent of the LDL receptor
Jean Z Lin1, Alexandro J Martagón, Willa A Hsueh
1Department of Biology and Biochemistry, Center for Nuclear Receptors and Cell Signaling, University of Houston, Houston, TX 77204, USA.
Abstract:
The majority of cholesterol reduction therapies, such as the statin drugs, work primarily by inducing the expression of hepatic low-density lipoprotein receptors (LDLRs), rendering these therapeutics only partially effective in animals lacking LDLRs. Although thyroid hormones and their synthetic derivatives, often referred to as thyromimetics, have been clearly shown to reduce serum cholesterol levels, this action has generally been attributed to their ability to increase expression of hepatic LDLRs. Here we show for the first time that the thyroid hormone T(3) and the thyroid hormone receptor-β selective agonists GC-1 and KB2115 are capable of markedly reducing serum cholesterol in mice devoid of functional LDLRs by inducing Cyp7a1 expression and stimulating the conversion and excretion of cholesterol as bile acids. Based on this LDLR-independent mechanism, thyromimetics such as GC-1 and KB2115 may represent promising cholesterol-lowering therapeutics for the treatment of diseases such as homozygous familial hypercholesterolemia, a rare genetic disorder caused by a complete lack of functional LDLRs, for which there are limited treatment options because most therapeutics are only minimally effective.
Insights
Thyroid hormones and thyromimetics significantly lower cholesterol in mice lacking low-density lipoprotein receptors (LDLRs). This LDLR-independent action involves increasing bile acid production, offering hope for treating genetic hypercholesterolemia.
Area of Science:
- Biochemistry
- Endocrinology
- Pharmacology
Background:
- Most cholesterol-lowering drugs, like statins, rely on hepatic low-density lipoprotein receptors (LDLRs) for efficacy.
- Thyroid hormones and thyromimetics are known to reduce serum cholesterol, typically attributed to LDLR upregulation.
Purpose of the Study:
- To investigate the cholesterol-lowering mechanism of thyroid hormone T(3) and thyromimetics (GC-1, KB2115) in LDLR-deficient mice.
- To explore an LDLR-independent pathway for cholesterol reduction.
Main Methods:
- Administration of T(3), GC-1, and KB2115 to mice lacking functional LDLRs.
- Measurement of serum cholesterol levels.
- Analysis of Cyp7a1 expression and bile acid production.
Main Results:
- Thyroid hormone T(3) and thyromimetics GC-1 and KB2115 markedly reduced serum cholesterol in LDLR-deficient mice.
- This reduction was achieved through induction of Cyp7a1 expression, enhancing cholesterol conversion to bile acids.
- Demonstrated an LDLR-independent mechanism for cholesterol reduction.
Conclusions:
- Thyromimetics like GC-1 and KB2115 offer a promising therapeutic strategy for cholesterol reduction independent of LDLR function.
- These agents may be effective for treating genetic disorders like homozygous familial hypercholesterolemia, where conventional therapies are limited.
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