Megalin binds and internalizes angiotensin-(1-7).
Megalin is a multiligand receptor heavily involved in protein endocytosis. We recently demonstrated that megalin binds and mediates internalization of ANG II. Although there is a strong structural resemblance between ANG II and ANG-(1-7), their physiological actions and their affinity for the angiotensin type 1 receptor (AT(1)R) are dissimilar. Therefore, the hypothesis of the present work was to test whether megalin binds and internalizes ANG-(1-7). The uptake of ANG-(1-7) was determined by exposure of confluent monolayers of BN/MSV cells (a model representative of the yolk sac epithelium) to fluorescently labeled ANG-(1-7) (100 nM) and measurement of the amount of cell-associated fluorescence after 4 h by flow cytometry. Anti-megalin antisera and an AT(1)R blocker (olmesartan) were used to interfere with uptake via megalin and the AT(1)R, respectively. ANG-(1-7) uptake was prevented by anti-megalin antisera (63%) to a higher degree than olmesartan (13%) (P < 0.001). In analysis by flow cytometry of binding experiments performed in brush-border membrane vesicles isolated from kidneys of CD-1 mice, anti-megalin antisera interfered with ANG-(1-7) binding more strongly than olmesartan (P < 0.05 against positive control). Interactions of megalin with ANG-(1-7) at a molecular level were studied by surface plasmon resonance, demonstrating that ANG-(1-7) binds megalin dose and time dependently and with an affinity similar to ANG II. These results show that the scavenger receptor megalin binds and internalizes ANG-(1-7).
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- Yolk Sac
- Urology & Nephrology
- Renin-Angiotensin System
- Peptide Fragments
- Low Density Lipoprotein Receptor-Related Protein-2
- Kidney
- Humans
- Flow Cytometry
- Epithelium
- Cell Culture Techniques
Citation
Published In
DOI
ISSN
Publication Date
Volume
Issue
Start / End Page
Location
Related Subject Headings
- Yolk Sac
- Urology & Nephrology
- Renin-Angiotensin System
- Peptide Fragments
- Low Density Lipoprotein Receptor-Related Protein-2
- Kidney
- Humans
- Flow Cytometry
- Epithelium
- Cell Culture Techniques