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Rab30 facilitates lipid homeostasis during fasting
Danielle M Smith1,2, Brian Y Liu1, Michael J Wolfgang3,4,5
1Department of Physiology, The Johns Hopkins University School of Medicine, Baltimore, MD, 21205, USA.
Nature Communications
|May 25, 2024
Summary
Rab30 protein regulates lipoprotein transport in liver cells, particularly during fasting. Its deficiency improves lipid profiles by reducing circulating triglycerides and cholesterol.
Area of Science:
- Cell Biology
- Molecular Biology
- Metabolic Diseases
Background:
- Hepatocytes utilize intracellular trafficking, regulated by Rab GTPases, for inter-tissue communication.
- The role of Rab30 in lipid metabolism and lipoprotein secretion remains largely uncharacterized.
Purpose of the Study:
- To investigate the function of Rab30 in hepatic lipid metabolism and lipoprotein trafficking.
- To determine the impact of Rab30 deficiency on serum lipid levels, especially under conditions of impaired fatty acid oxidation.
Main Methods:
- Utilized whole-body, liver-specific, and double knockout mouse models (Rab30 and Carnitine palmitoyltransferase 2).
- Employed live-cell super-resolution imaging and in vivo proximity labeling to track Rab30-vesicle dynamics.
- Quantified serum triglyceride, cholesterol, and apolipoprotein A4 (ApoA4) levels.
Main Results:
- Rab30 expression is induced in the liver by fasting and further amplified in Cpt2 knockout mice.
- Rab30-marked vesicles actively participate in the secretory pathway.
- Rab30 deficiency in double knockout mice ameliorates the dyslipidemia observed in Cpt2 knockout mice, reducing serum triglycerides and cholesterol.
- ApoA4 protein levels are decreased in circulation but not in the liver of double knockout mice, indicating a trafficking defect.
Conclusions:
- Rab30 plays a crucial role in the selective sorting and secretion of lipoproteins from hepatocytes.
- This function of Rab30 is particularly important in managing circulating triglyceride levels during excessive lipid burden or impaired fatty acid oxidation.
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