Apicobasal transferrin receptor localization and trafficking in brain capillary endothelial cells

Fluids and Barriers of the CNS

Research

Kristine Langthaler¹  Morten S. Nielsen²  Simone S. E. Nielsen²  Mikkel R. Holst²  Elisabeth Helena Bruun²  Birger Brodin³  Sarah Christine Christensen⁴ 

[1] CNS Drug Delivery and Barrier Modelling, University of Copenhagen, Copenhagen, Denmark;Translational DMPK, H. Lundbeck A/S, Copenhagen, Denmark;Department of Biomedicine, Faculty of Health, Aarhus University, 8000, Aarhus C, Denmark;Department of Pharmacy, Faculty of Health and Medical Sciences, University of Copenhagen, 2100, Copenhagen, Denmark;Pathology & Imaging, Novo Nordisk, Måløv, Denmark;

关键词: Transferrin receptor (TfR);    Intracellular trafficking;    Apicobasal polarity;    Brain drug delivery;    Blood–brain barrier;    Brain endothelial cells;    Expansion microscopy;   

DOI  :  10.1186/s12987-022-00404-1

 received in 2022-11-04, accepted in 2022-12-28,  发布年份 2022

来源: Springer

【 摘 要 】

The detailed mechanisms by which the transferrin receptor (TfR) and associated ligands traffic across brain capillary endothelial cells (BECs) of the CNS-protective blood–brain barrier constitute an important knowledge gap within maintenance and regulation of brain iron homeostasis. This knowledge gap also presents a major obstacle in research aiming to develop strategies for efficient receptor-mediated drug delivery to the brain. While TfR-mediated trafficking from blood to brain have been widely studied, investigation of TfR-mediated trafficking from brain to blood has been limited. In this study we investigated TfR distribution on the apical and basal plasma membranes of BECs using expansion microscopy, enabling sufficient resolution to separate the cellular plasma membranes of these morphological flat cells, and verifying both apical and basal TfR membrane domain localization. Using immunofluorescence-based transcellular transport studies, we delineated endosomal sorting of TfR endocytosed from the apical and basal membrane, respectively, as well as bi-directional TfR transcellular transport capability. The findings indicate different intracellular sorting mechanisms of TfR, depending on the apicobasal trafficking direction across the BBB, with the highest transcytosis capacity in the brain-to-blood direction. These results are of high importance for the current understanding of brain iron homeostasis. Also, the high level of TfR trafficking from the basal to apical membrane of BECs potentially explains the low transcytosis which are observed for the TfR-targeted therapeutics to the brain parenchyma.

【 授权许可】

CC BY   
© The Author(s) 2023. corrected publication 2023

【 图 表 】

Fig. 3

40517_2023_252_Article_IEq49.gif

Fig. 2

Fig. 2

42004_2023_911_Article_IEq042.gif

42004_2023_911_Article_IEq041.gif

42004_2023_911_Article_IEq30.gif

42004_2023_911_Article_IEq15.gif