Cellular entry of G3.5 poly (amido amine) dendrimers by clathrin- and dynamin-dependent endocytosis promotes tight junctional opening in intestinal epithelia.
OBJECTIVE
This study investigates the mechanisms of G3.5 poly (amido amine) dendrimer cellular uptake, intracellular trafficking, transepithelial transport and tight junction modulation in Caco-2 cells in the context of oral drug delivery.


METHODS
Chemical inhibitors blocking clathrin-, caveolin- and dynamin-dependent endocytosis pathways were used to investigate the mechanisms of dendrimer cellular uptake and transport across Caco-2 cells using flow cytometry and confocal microscopy.


RESULTS
Dendrimer cellular uptake was found to be dynamin-dependent and was reduced by both clathrin and caveolin endocytosis inhibitors, while transepithelial transport was only dependent on dynamin- and clathrin-mediated endocytosis. Dendrimers were quickly trafficked to the lysosomes after 15 min of incubation and showed increased endosomal accumulation at later time points, suggesting saturation of this pathway. Dendrimers were unable to open tight junctions in cell monolayers treated with dynasore, a selective inhibitor of dynamin, confirming that dendrimer internalization promotes tight junction modulation.


CONCLUSIONS
G3.5 PAMAM dendrimers take advantage of several receptor-mediated endocytosis pathways for cellular entry in Caco-2 cells. Dendrimer internalization by dynamin-dependent mechanisms promotes tight junction opening, suggesting that dendrimers act on intracellular cytoskeletal proteins to modulate tight junctions, thus catalyzing their own transport via the paracellular route.
Goldberg
Deborah S
DS
Fischell Department of Bioengineering, University of Maryland, College Park, Maryland 20742, USA.
Ghandehari
Hamidreza
H
Swaan
Peter W
PW
D001692:Biological Transport; D018938:Caco-2 Cells; D002966:Clathrin / Q000378:metabolism*; D050091:Dendrimers / Q000493:pharmacokinetics* / Q000494:pharmacology; D034281:Dynamins / Q000378:metabolism*; D004705:Endocytosis / Q000502:physiology*; D005434:Flow Cytometry; D006801:Humans; D007413:Intestinal Mucosa / Q000187:drug effects* / Q000502:physiology; D018613:Microscopy, Confocal; D019108:Tight Junctions / Q000187:drug effects / Q000378:metabolism
D002966:Clathrin; D050091:Dendrimers; C522260:PAMAM G3.5 dendrimer; D034281:Dynamins
Pharm Res. 2003 Nov;20(11):1812-9
14661926
Dev Cell. 2006 Jun;10(6):839-50
16740485
Curr Med Chem. 2007;14(23):2482-8
17979701
Biosci Biotechnol Biochem. 2009 Feb;73(2):328-34
19202294
Pharm Res. 2008 Jul;25(7):1723-9
18438703
Eur J Health Econ. 2007 Jun;8(2):145-51
17333088
Int J Pharm. 2010 Jan 15;384(1-2):189-94
19825406
Pharm Res. 2000 Aug;17(8):991-8
11028947
J Cell Sci. 2001 Oct;114(Pt 20):3737-47
11707525
Int J Pharm. 2003 Feb 18;252(1-2):263-6
12550802
Biochem Soc Trans. 2007 Feb;35(Pt 1):61-7
17233602
J Pharm Sci. 2008 Jun;97(6):2208-16
17879294
J Gen Virol. 2008 Sep;89(Pt 9):2147-2156
18753224
Int J Pharm. 2007 May 4;336(1):183-90
17188439
Pharm Res. 2003 Oct;20(10):1543-50
14620505
FEBS Lett. 1991 Apr 9;281(1-2):188-90
1901801
Pharm Res. 2006 Dec;23(12):2818-26
17094034
Pharm Res. 2007 Nov;24(11):2138-45
17701324