Effect of flow on endothelial endocytosis of nanocarriers targeted to ICAM-1.

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TitleEffect of flow on endothelial endocytosis of nanocarriers targeted to ICAM-1.
Publication TypeJournal Article
Year of Publication2012
AuthorsBhowmick, T, Berk, E, Cui, X, Muzykantov, VR, Muro, S
JournalJ Control Release
Volume157
Issue3
Pagination485-92
Date Published2012 Feb 10
ISSN1873-4995
KeywordsAnimals, Antibodies, Monoclonal, Drug Carriers, Endocytosis, Endothelial Cells, Human Umbilical Vein Endothelial Cells, Humans, Intercellular Adhesion Molecule-1, Mice, Mice, Inbred C57BL, Nanoparticles, Polystyrenes
Abstract

Delivery of drugs into the endothelium by nanocarriers targeted to endothelial determinants may improve treatment of vascular maladies. This is the case for intercellular adhesion molecule 1 (ICAM-1), a glycoprotein overexpressed on endothelial cells (ECs) in many pathologies. ICAM-1-targeted nanocarriers bind to and are internalized by ECs via a non-classical pathway, CAM-mediated endocytosis. In this work we studied the effects of endothelial adaptation to physiological flow on the endocytosis of model polymer nanocarriers targeted to ICAM-1 (anti-ICAM/NCs, ~180 nm diameter). Culturing established endothelial-like cells (EAhy926 cells) and primary human umbilical vein ECs (HUVECs) under 4 dyn/cm(2) laminar shear stress for 24 h resulted in flow adaptation: cell elongation and formation of actin stress fibers aligned to the flow direction. Fluorescence microscopy showed that flow-adapted cells internalized anti-ICAM/NCs under flow, although at slower rate versus non flow-adapted cells under static incubation (~35% reduction). Uptake was inhibited by amiloride, whereas marginally affected by filipin and cadaverine, implicating that CAM-endocytosis accounts for anti-ICAM/NC uptake under flow. Internalization under flow was more modestly affected by inhibiting protein kinase C, which regulates actin remodeling during CAM-endocytosis. Actin recruitment to stress fibers that maintain the cell shape under flow may delay uptake of anti-ICAM/NCs under this condition by interfering with actin reorganization needed for CAM-endocytosis. Electron microscopy revealed somewhat slow, yet effective endocytosis of anti-ICAM/NCs by pulmonary endothelium after i.v. injection in mice, similar to that of flow-adapted cell cultures: ~40% (30 min) and 80% (3 h) internalization. Similar to cell culture data, uptake was slightly faster in capillaries with lower shear stress. Further, LPS treatment accelerated internalization of anti-ICAM/NCs in mice. Therefore, regulation of endocytosis of ICAM-1-targeted nanocarriers by flow and endothelial status may modulate drug delivery into ECs exposed to different physiological (capillaries vs. arterioles/venules) or pathological (ischemia, inflammation) levels and patterns of blood flow.

DOI10.1016/j.jconrel.2011.09.067
Alternate JournalJ Control Release
PubMed ID21951807
PubMed Central IDPMC3274617
Grant ListR01 EB006818 / EB / NIBIB NIH HHS / United States
R01 HL087036 / HL / NHLBI NIH HHS / United States
R01 HL087036-01A2 / HL / NHLBI NIH HHS / United States
R01 HL098416 / HL / NHLBI NIH HHS / United States
R01 HL098416-01 / HL / NHLBI NIH HHS / United States
R01 HL098416-04 / HL / NHLBI NIH HHS / United States