Hyperlipidemia and hepatitis in liver-specific CREB3L3 knockout mice generated using a one-step CRISPR/Cas9 system

Area of Science:

• Molecular Biology
• Metabolic Research
• Genetics

Background:

• cAMP responsive element binding protein 3-like 3 (CREB3L3) is a transcription factor crucial for energy homeostasis during fasting.
• Tissue-specific knockout models for CREB3L3, particularly in the liver and small intestine, were previously unavailable.

Purpose of the Study:

• To generate the first liver- and small intestine-specific CREB3L3 knockout mouse models.
• To investigate the specific roles of CREB3L3 in hepatic and intestinal lipid metabolism and energy homeostasis.

Main Methods:

• Utilized the one-step CRISPR/Cas9 gene editing system to create CREB3L3 floxed mice.
• Generated liver-specific knockout (LKO) and small intestine-specific knockout (IKO) mice from floxed models.
• Analyzed metabolic phenotypes, including plasma lipid levels and gene expression, under normal and dietary stress conditions (methionine-choline deficient diet).

Main Results:

• Liver-specific CREB3L3 knockout (LKO) mice developed hypertriglyceridemia and hypercholesterolemia, unlike global KO mice which showed hypocholesterolemia.
• LKO mice exhibited upregulation of hepatic Srebf2 and its target genes, indicating altered cholesterol synthesis pathways.
• No significant phenotypic differences were observed in small intestine-specific knockout (IKO) mice compared to controls.
• LKO mice showed severe liver injury when fed a methionine-choline deficient diet, a model for non-alcoholic steatohepatitis.

Conclusions:

• Hepatic CREB3L3 plays a significant role in regulating plasma triglyceride metabolism.
• Both hepatic and intestinal CREB3L3 contribute to cholesterol metabolism.
• CREB3L3 is essential for maintaining liver health and preventing steatohepatitis under metabolic stress.