Application and trend of bioluminescence imaging in metabolic syndrome research

Abstract

Bioluminescence imaging is a non-invasive technology used to visualize physiological processes in animals and is useful for studying the dynamics of metabolic syndrome. Metabolic syndrome is a broad spectrum of diseases which are rapidly increasing in prevalence, and is closely associated with obesity, type 2 diabetes, nonalcoholic fatty liver disease, and circadian rhythm disorder. To better serve metabolic syndrome research, researchers have established a variety of animal models expressing luciferase, while also committing to finding more suitable luciferase promoters and developing more efficient luciferase-luciferin systems. In this review, we systematically summarize the applications of different models for bioluminescence imaging in the study of metabolic syndrome.

Keywords: adipose inflammation; bioluminescence imaging; circadian rhythm disorders; metabolic syndrome; model; non-alcoholic fatty liver; obesity; type 2 diabetes.

FIGURE 1

The process of bioluminescence imaging (BLI) in a mouse model. (A) Using transgenic technology, embryos are made to contain the luciferase gene under the control of a specific promoter. (B) Transgenic mice are injected intraperitoneally with fluorescein. (C) After anesthetizing the transgenic mice, a charge-coupled device (CCD) camera is used for signal acquisition. (D) Bioluminescence imaging is obtained from transgenic mice.

FIGURE 2

Autonomous circadian rhythm of human islets. (A) Luciferase and green fluorescent protein (GFP) are co-expressed in islet cells, and at least half of the cells in a single islet produce luciferase as demonstrated by the detection of GFP expression. (B) The expression of Bmal1-Luc had a distinct rhythm, with a cycle length of 23.6 ± .4 h, proving the existence of an autonomous circadian rhythm in human pancreatic islets. Reprinted (adapted) with permission from (Pulimeno et al., 2013).

FIGURE 3

Principles of bioluminescence imaging of FFA-luc probes. (A) Bioluminescence imaging of transgenic mice expressing luciferase systemically or specifically in the liver after intraperitoneal injection of FFA-luc probes. (B) FFA-luc probes are transported into cells by transporters and reduced by intracellular glutathione to release free fluorescein. Luciferase catalyzes luciferin to produce photons that are detected by a charge-coupled device (CCD) camera. Reprinted (adapted) with permission from (Henkin et al., 2012). Copyright 2012 American Chemical Society.