Related Experiment Video

Updated: Aug 16, 2026

A Human Ex Vivo Atherosclerotic Plaque Model to Study Lesion Biology
05:51

A Human Ex Vivo Atherosclerotic Plaque Model to Study Lesion Biology

Published on: May 6, 2014

Regulation and splicing of scavenger receptor class B type I in human macrophages and atherosclerotic plaques

Per-Arne Svensson1, Mikael C O Englund, Magnus S C Snäckestrand

  • 1Research Centre for Endocrinology & Metabolism, Department of Internal Medicine, The Sahlgrenska Academy, Göteborg University, S-413 45 Göteborg, Sweden. Per-Arne.Svensson@medic.gu.se

BMC Cardiovascular Disorders
|August 27, 2005
PubMed

Insights

Scavenger receptor class B type I (SR-BI) expression in human macrophages is influenced by proatherogenic factors but does not differ between atherosclerosis patients and healthy individuals. A novel SR-BI isoform, SR-BIII, was identified in human macrophages and plaques.

Area of Science:

  • Cardiovascular Biology
  • Molecular Medicine
  • Atherosclerosis Research

Background:

  • High-density lipoprotein (HDL) plays a protective role in cardiovascular health via reverse cholesterol transport.
  • Scavenger receptor class B type I (SR-BI) facilitates cholesterol uptake to HDL, but its role in human atherosclerosis is not fully understood.
  • Investigating SR-BI expression in human macrophages and atherosclerotic plaques is crucial for understanding its involvement in human cardiovascular disease.

Purpose of the Study:

  • To investigate the expression of SR-BI and its isoforms in human macrophages and atherosclerotic plaques.
  • To determine the effect of proatherogenic stimuli like hypoxia and minimally modified low-density lipoprotein (mmLDL) on SR-BI expression in human macrophages.
  • To compare SR-BI expression levels in macrophages from patients with atherosclerosis versus healthy controls.

Main Methods:

  • Human monocyte-derived macrophages from healthy subjects were treated with hypoxia and mmLDL.
  • SR-BI expression was quantified using real-time PCR.
  • SR-BI isoforms were identified and characterized in macrophages and atherosclerotic plaques using RT-PCR and DNA sequencing.

Main Results:

  • Hypoxia decreased SR-BI expression, while mmLDL increased it in human macrophages.
  • No significant difference in SR-BI expression was observed between macrophages from atherosclerosis patients and healthy controls.
  • Three SR-BI isoforms (SR-BI, SR-BII, and a novel SR-BIII) were detected in human macrophages and atherosclerotic plaques, with SR-BIII possessing a unique C-terminal domain.

Conclusions:

  • SR-BI expression in human macrophages is modulated by proatherogenic stimuli but does not appear to be a common cause of atherosclerosis.
  • Altered SR-BI expression is unlikely to be a primary driver of atherosclerosis in humans.
  • A novel SR-BI isoform, SR-BIII, has been identified and characterized in human macrophages and atherosclerotic lesions.
Abstract

Related Concept Videos

Inflammation01:38

Inflammation

Overview
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...
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...
Atherosclerosis I: Introduction01:30

Atherosclerosis I: Introduction

Atherosclerosis is a progressive disorder characterized by the buildup of plaques on the arterial inner wall, causing them to narrow and harden over time. These plaques comprise lipids, calcium, blood components, carbohydrates, and fibrous tissue. The process primarily affects the intima of large and medium-sized arteries, reducing blood flow in any artery.Etiology and risk factorsThe cause of atherosclerosis is multifactorial, involving a complex interplay among endothelial injury, lipid...
Receptor-mediated Endocytosis01:38

Receptor-mediated Endocytosis

Overview
RNA Splicing01:32

RNA Splicing

Splicing is the process by which eukaryotic RNA is edited before its translation into protein. The RNA strand transcribed from eukaryotic DNA is called the primary transcript. The primary transcripts that become mRNAs are called precursor messenger RNAs (pre-mRNAs). Eukaryotic pre-mRNA contains alternating sequences of exons and introns. Exons are nucleotide sequences that code for proteins, whereas introns are the non-coding regions. In RNA splicing, introns are removed and exons are bonded...