AMPK Methods and Protocols

Chapter 30

Methods to Evaluate AMPK Regulation of Macrophage

Cholesterol Homeostasis

Nicholas D. LeBlond and Morgan D. Fullerton

Abstract

Macrophages are a driving force in the development and progression of atherosclerosis, a chronic condition
that can lead to cardiovascular disease. In this chapter we describe methods that monitor macrophage
cholesterol homeostasis such as cholesterol synthesis, uptake, and efflux, all with the use of AMPK activators
and potential genetic models that could help shed light on the role of this metabolic regulator in
atherosclerosis and other chronic diseases.

Key wordsCholesterol homeostasis, Macrophages, Atherosclerosis, AMP-activated protein kinase,

Reverse cholesterol transport

1 Introduction

Atherosclerosis is a chronic inflammatory disease preceding numer-

ous acute coronary artery complications, the combination of which

accounts for ~25% of deaths worldwide [1]. Macrophages are a key

player in the progression and potential therapeutic targeting of

atherosclerosis [2, 3]. Atherosclerotic plaque, in addition to other

cell types, is recognized for the accumulation of cholesterol-rich,

lipid-laden macrophages (termed “foam cells”). In response to

environmental cues, plaque macrophages upregulate scavenger

receptors that bind and internalize cholesterol-rich low-density

lipoproteins (LDL) that have been modified (usually oxidized or

aggregated). The LDL receptor-mediated uptake of lipoproteins is

under intricate feedback mechanisms that tightly control the

amount of cellular cholesterol taken into the cell. However, modi-

fication of LDL particles results in the unregulated uptake and

retention of cholesterol within cytoplasmic lipid droplets [4],

which can lead to plaque instability and rupture. Moreover, cellular

lipid burden contributes to a vicious cycle of impaired lipid efflux,

defective macrophage efferocytosis and egress, and can further

promote the infiltration and activation of numerous adaptive and

Dietbert Neumann and Benoit Viollet (eds.),AMPK:MethodsandProtocols, Methods in Molecular Biology, vol. 1732,
https://doi.org/10.1007/978-1-4939-7598-3_30,©Springer Science+Business Media, LLC 2018

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