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Key protein that binds to LDL cholesterol identified

Date:
November 21, 2016
Source:
Yale University
Summary:
A protein that plays an important role in the buildup of LDL cholesterol in blood vessels has been identified by researchers. The finding could lead to an additional strategy to block LDL accumulation, which could help prevent or slow the clogging of arteries that leads to heart disease, the researchers said.
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FULL STORY

Cells expressing the newly described LDL binding protein ALK1 (green).
Credit: Image courtesy of Yale University

A Yale-led research team identified a protein that plays an important role in the buildup of LDL cholesterol in blood vessels. The finding could lead to an additional strategy to block LDL accumulation, which could help prevent or slow the clogging of arteries that leads to heart disease, the researchers said.

The study was published on Nov. 21 by Nature Communications.

Arteries become clogged with fats and cholesterol when certain proteins in the body, known as lipoproteins, combine with and transport fats in the blood to cells. Scientists have long believed that the LDL receptor molecule was responsible for the transport of LDL within cells. But given that some individuals lacking the LDL receptor still have high levels of LDL, questions remained about the mechanism.

To identify the mechanism, the research team screened more than 18,000 genes from the endothelium -- the inner layer of human blood vessels. They examined the transfer of LDL into endothelial cells and then focused on possible genes involved in the process.

The researchers found that a protein called ALK1 facilitated LDL's pathway into cells. "We confirmed that ALK1 directly binds to LDL," said William C. Sessa, senior author and the Alfred Gilman Professor of Pharmacology and professor of medicine (cardiology). The team also determined that the "LDL-ALK1 pathway" aided the transport of LDL from blood into tissue.

The role of ALK1 in LDL accumulation was not previously known, said Sessa.

"The discovery of ALK1 as an LDL-binding protein implies that it might initiate the early phases of atherosclerosis," he noted. "If we can find a way of blocking ALK1 using small molecules or antibodies, it might be used in combination with lipid-lowering strategies."

Current lipid-lowering strategies include statins, which target LDL cholesterol levels in the blood.

A therapeutic that blocks ALK1 "would be a unique strategy for reducing the burden of atherosclerosis and be synergistic with lipid- lowering therapies," Sessa noted.

Heart disease caused by damage to blood vessels is the leading cause of death worldwide.


Story Source:

Materials provided by Yale University. Original written by Ziba Kashef. Note: Content may be edited for style and length.


Journal Reference:

  1. Jan R. Kraehling, John H. Chidlow, Chitra Rajagopal, Michael G. Sugiyama, Joseph W. Fowler, Monica Y. Lee, Xinbo Zhang, Cristina M. Ramírez, Eon Joo Park, Bo Tao, Keyang Chen, Leena Kuruvilla, Bruno Larriveé, Ewa Folta-Stogniew, Roxana Ola, Noemi Rotllan, Wenping Zhou, Michael W. Nagle, Joachim Herz, Kevin Jon Williams, Anne Eichmann, Warren L. Lee, Carlos Fernández-Hernando, William C. Sessa. Genome-wide RNAi screen reveals ALK1 mediates LDL uptake and transcytosis in endothelial cells. Nature Communications, 2016; 7: 13516 DOI: 10.1038/NCOMMS13516

Cite This Page:

Yale University. "Key protein that binds to LDL cholesterol identified." ScienceDaily. ScienceDaily, 21 November 2016. <www.sciencedaily.com/releases/2016/11/161121175611.htm>.
Yale University. (2016, November 21). Key protein that binds to LDL cholesterol identified. ScienceDaily. Retrieved May 28, 2017 from www.sciencedaily.com/releases/2016/11/161121175611.htm
Yale University. "Key protein that binds to LDL cholesterol identified." ScienceDaily. www.sciencedaily.com/releases/2016/11/161121175611.htm (accessed May 28, 2017).

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