Related Experiment Video

Updated: Aug 9, 2026

Monitoring Cleaved Caspase-3 Activity and Apoptosis of Immortalized Oligodendroglial Cells using Live-cell Imaging and Cleaveable Fluorogenic-dye Substrates Following Potassium-induced Membrane Depolarization
10:45

Monitoring Cleaved Caspase-3 Activity and Apoptosis of Immortalized Oligodendroglial Cells using Live-cell Imaging and Cleaveable Fluorogenic-dye Substrates Following Potassium-induced Membrane Depolarization

Published on: January 13, 2012

7-ketocholesterol induces protein ubiquitination, myelin figure formation, and light chain 3 processing in vascular

Wim Martinet1, Martine De Bie, Dorien M Schrijvers

  • 1Division of Pharmacology, University of Antwerp, Wilrijk, Belgium. wim.martinet@ua.ac.be

Arteriosclerosis, Thrombosis, and Vascular Biology
|October 2, 2004
PubMed
Abstract

Insights

7-ketocholesterol (7-KC) triggers smooth muscle cell death in atherosclerosis by activating the ubiquitin-proteasome system and inducing autophagic processes, leading to cellular damage.

Area of Science:

  • Cardiovascular Biology
  • Cell Death Mechanisms
  • Atherosclerosis Research

Background:

  • Oxysterols, like 7-ketocholesterol (7-KC), are implicated in the cell death observed in atherosclerosis.
  • Understanding the mechanisms of 7-KC-induced cell death in smooth muscle cells (SMCs) is crucial for atherosclerosis research.

Purpose of the Study:

  • To investigate the mechanisms underlying human smooth muscle cell (SMC) death induced by 7-ketocholesterol (7-KC).

Main Methods:

  • Human aortic SMCs were treated with 7-KC.
  • Analysis included oxidative stress markers, gene expression (mRNA and protein), cell viability assays (neutral red, cell counting, mitochondrial membrane potential), proteasome inhibition, transmission electron microscopy, and autophagosome formation markers (LysoTracker, LC3).
  • Ubiquitination in human atherosclerotic plaques was also examined.

Main Results:

  • 7-KC treatment increased oxidative stress markers and upregulated stress-related genes at the mRNA level in SMCs.
  • 7-KC induced rapid SMC death, characterized by mitochondrial dysfunction, ubiquitin-proteasome system activation, and protein ubiquitination.
  • Inhibition of the proteasome enhanced 7-KC toxicity, and electron microscopy revealed myelin figures and autophagosome formation, suggesting autophagic processes.

Conclusions:

  • 7-ketocholesterol activates the ubiquitin-proteasome system in SMCs.
  • 7-KC induces a complex cell death pathway involving myelin figure formation and LC3 processing, indicative of autophagic processes.
  • Findings in vitro are consistent with ubiquitination observed in SMCs within human atherosclerotic plaques.

More Related Videos

Enrichment of Mammalian Tissues and Xenopus Oocytes with Cholesterol10:12

Enrichment of Mammalian Tissues and Xenopus Oocytes with Cholesterol

Published on: March 25, 2020

Evaluation of Substrate Ubiquitylation by E3 Ubiquitin-ligase in Mammalian Cell Lysates09:47

Evaluation of Substrate Ubiquitylation by E3 Ubiquitin-ligase in Mammalian Cell Lysates

Published on: May 10, 2022

Related Concept Videos

Intralumenal Vesicles and Multivesicular Bodies01:38

Intralumenal Vesicles and Multivesicular Bodies

Intraluminal vesicles (ILVs) are small vesicles 50-80 nm in diameter formed during the maturation of early endosomes. A specialized endosome containing numerous ILVs is called a multivesicular body (MVB). ILVs contain internalized molecules such as antigens, nucleic acids, proteins, and metabolites. Some of these molecules are released from the MVBs inside exosomes and are transported to other cells. Other MVBs contain molecules that are retained in the ILVs and are later degraded within the...
Regulation of Nuclear Protein Sorting01:45

Regulation of Nuclear Protein Sorting

Nuclear protein sorting regulates nucleus composition and gene expression, crucial for determining the fate of a eukaryotic cell. Hence, the entry and exit of molecules across the nuclear envelope is a tightly controlled process. Nuclear protein sorting can be inhibited by one of the following ways: 1) masking cargo signal sequences, 2) modifying the nuclear receptor's affinity for cargo, 3) controlling the nuclear pore size, 4) retaining the cargo during its transit to the cytosol or the...
Smooth Endoplasmic Reticulum01:21

Smooth Endoplasmic Reticulum

Smooth endoplasmic reticulum or smooth ER is a sub-organelle with specialized functions in animal cells and plant cells. It is often associated with the tubule morphology of the endoplasmic reticulum.
The ER provides optimal conditions for synthesizing steroid hormones and lipids, such as phospholipids and triglycerides. Traditionally, lipid metabolism was considered to be a smooth ER function. However, there is no direct evidence to prove that rough ER is completely excluded from lipid...
Receptor Downregulation in MVBs01:15

Receptor Downregulation in MVBs

Multivesicular bodies (MVBs) are mature endosomes that sort ubiquitinated proteins and then fuse with lysosomes to degrade the sorted proteins. Epidermal growth factor (EGF) and its receptor (EGFR) form a complex that can be internalized through endocytosis, sorted into an MVB, and later degraded.
The EGFR can initiate signaling pathways that  lead to cell proliferation, migration, and differentiation. Overexpression of EGFR  stimulates cells to proliferate. Excessive  EGFR activation may...
Nervous Tissue: Myelin01:25

Nervous Tissue: Myelin

The myelin sheath is a multilayered lipid and protein covering that insulates the axon of a neuron, enhancing the speed of nerve impulse conduction. Axons without this sheath are referred to as unmyelinated. Two types of neuroglia, Schwann cells in the peripheral nervous system (PNS) and oligodendrocytes in the central nervous system (CNS) are responsible for producing myelin sheaths.
Schwann cells begin to form myelin sheaths around axons during fetal development. They wrap around a small...
Cholesterol: Significance and Regulation01:29

Cholesterol: Significance and Regulation

Although not a source of energy, cholesterol plays a significant role as a foundational structure for bile salts, steroid hormones, and vitamin D, as well as being a crucial component of plasma membranes. Approximately 15% of blood cholesterol is derived from our diet, with the remainder synthesized from acetyl CoA by the liver and intestines. Cholesterol is eliminated from the body through its conversion into bile salts, which are eventually discarded in the feces.
Considering cholesterol and...