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Receptor-Mediated Endocytosis of VEGF-A in Rat Liver Sinusoidal Endothelial Cells
Joint Authors
Mousavi, Seyed Ali
Skjeldal, Frode
Fønhus, Marita Sporstøl
Haugen, Linda Hofstad
Eskild, Winnie
Berg, Trond
Bakke, Oddmund
Source
Issue
Vol. 2019, Issue 2019 (31 Dec. 2019), pp.1-12, 12 p.
Publisher
Hindawi Publishing Corporation
Publication Date
2019-09-10
Country of Publication
Egypt
No. of Pages
12
Main Subjects
Abstract EN
Background and Aims.
Vascular endothelial growth factor (VEGF) receptors (VEGFR1 and VEGFR2) bind VEGF-A with high affinity.
This study sought to determine the relative contributions of these two receptors to receptor-mediated endocytosis of VEGF-A and to clarify their endocytic itineraries in rat liver sinusoidal endothelial cells (LSECs).
Methods.
Isolated LSECs and radiolabeled VEGF-A were used to examine surface binding and receptor-mediated endocytosis.
Quantitative real time RT-PCR (Q-RT-PCR) and Western blotting were applied to demonstrate receptor expression.
Results.
Q-RT-PCR analysis showed that VEGFR1 and VEGFR2 mRNA were expressed in LSECs.
Ligand saturation analysis at 4°C indicated two different classes of [125I]-VEGFA binding sites on LSECs with apparent dissociation constants of 8 and 210 pM.
At 37°C, LSECs efficiently took up and degraded [125I]-VEGF-A for at least 2 hours.
Uptake of [125I]-VEGF-A by LSECs was blocked by dynasore that inhibits dynamin-dependent internalization, whereas inhibition of cysteine proteases by leupeptin inhibited degradation without affecting the uptake of [125I]-VEGF-A, suggesting that it is degraded following transport to lysosomes.
Incubation of LSECs in the continued presence of a saturating concentration of unlabeled VEGF-A at 37°C was associated with a loss of as much as 75% of the total VEGFR2 within 30 min as shown by Western blot analysis, whereas there was no appreciable decrease in protein levels for VEGFR1 after 120 min incubation, suggesting that VEGF-A stimulation downregulates VEGFR2, but not VEGFR1, in LSECs.
This possibility was supported by the observation that a hexapeptide that specifically blocks VEGF-A binding to VEGFR1 caused a marked reduction in the uptake of [125I]-VEGF-A, whereas a control peptide had no effect.
Finally, live cell imaging studies using a fluorescently labeled anti-VEGFR2 antibody showed that VEGFR2 was transported via early and late endosomes to reach endolysosomes where degradation of the VEGFR2 takes place.
Conclusion.
Our studies suggest that, subsequent to VEGF-A binding and internalization, the unoccupied VEGFR1 may recycle to the cell surface allowing its reutilization, whereas the majority of the internalized VEGFR2 is targeted for degradation.
American Psychological Association (APA)
Mousavi, Seyed Ali& Skjeldal, Frode& Fønhus, Marita Sporstøl& Haugen, Linda Hofstad& Eskild, Winnie& Berg, Trond…[et al.]. 2019. Receptor-Mediated Endocytosis of VEGF-A in Rat Liver Sinusoidal Endothelial Cells. BioMed Research International،Vol. 2019, no. 2019, pp.1-12.
https://search.emarefa.net/detail/BIM-1126089
Modern Language Association (MLA)
Mousavi, Seyed Ali…[et al.]. Receptor-Mediated Endocytosis of VEGF-A in Rat Liver Sinusoidal Endothelial Cells. BioMed Research International No. 2019 (2019), pp.1-12.
https://search.emarefa.net/detail/BIM-1126089
American Medical Association (AMA)
Mousavi, Seyed Ali& Skjeldal, Frode& Fønhus, Marita Sporstøl& Haugen, Linda Hofstad& Eskild, Winnie& Berg, Trond…[et al.]. Receptor-Mediated Endocytosis of VEGF-A in Rat Liver Sinusoidal Endothelial Cells. BioMed Research International. 2019. Vol. 2019, no. 2019, pp.1-12.
https://search.emarefa.net/detail/BIM-1126089
Data Type
Journal Articles
Language
English
Notes
Includes bibliographical references
Record ID
BIM-1126089