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Updated: Jun 15, 2026
09:29
Isolation of Targeted Hypothalamic Neurons for Studies of Hormonal, Metabolic, and Electrical Regulation
Published on: August 4, 2023
Unique leptin trafficking by a tailless receptor
Hong Tu1, Hung Hsuchou, Abba J Kastin
1Blood-Brain Barrier Group, Pennington Biomedical Research Center, 6400 Perkins Rd., Baton Rouge, LA 70808, USA.
Summary
Leptin transport across the blood-brain barrier does not require the leptin receptor's cytoplasmic sequence. This finding challenges previous assumptions about leptin transport mechanisms and obesity.
Area of Science:
- Neuroscience
- Cell Biology
- Endocrinology
Background:
- Impaired blood-to-brain leptin transport contributes to obesity.
- Leptin crosses the blood-brain barrier via transcytosis.
- Previous studies implicated the leptin receptor (ObR) cytoplasmic sequence in leptin transport.
Purpose of the Study:
- To identify specific structural domains of the ObR responsible for leptin transport.
- To investigate the role of the ObR intracellular sequence in leptin internalization and trafficking.
Main Methods:
- Generated ObR truncates with varying intracellular sequence lengths.
- Overexpressed ObR constructs in mammalian cells, including cerebral endothelia.
- Quantified leptin binding and endocytosis using Alexa-labeled leptin.
- Utilized clathrin and dynamin inhibitors (chlorpromazine, Dynasore) and caveolae inhibitors (nystatin, filipin).
Main Results:
- All mutant ObRs, including ObR860 (lacking cytoplasmic sequence), bound and internalized leptin.
- Leptin internalization occurred independently of the ObR cytoplasmic sequence.
- Cell type-dependent variations in intracellular trafficking were observed, involving clathrin- and dynamin-mediated endocytosis.
- Caveolae pathways were not involved in leptin transport.
Conclusions:
- Leptin internalization can occur without specific cytoplasmic sorting signals in the ObR.
- This challenges the established model of leptin transport across the blood-brain barrier.
- Findings have significant implications for understanding and potentially treating obesity.
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