Open AccessEncapsulated cargo internalized by fusogenic liposomes partially overlaps the endoplasmic reticulum
Author(s) -
Mustata Roxana C.,
Grigorescu Alina,
Petrescu Stefana M.
Publication year - 2009
Publication title -
journal of cellular and molecular medicine
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.44
H-Index - 130
eISSN - 1582-4934
pISSN - 1582-1838
DOI - 10.1111/j.1582-4934.2009.00724.x
Subject(s) - endosome , endoplasmic reticulum , endocytic cycle , microbiology and biotechnology , brefeldin a , golgi apparatus , endocytosis , organelle , kdel , clathrin , liposome , calcein , vesicle , biology , chemistry , biochemistry , cell , intracellular , membrane
Few endocytosed ligands, including bacterial toxins and simian virus 40 (SV40) have been shown to reach the endoplasmic reticulum (ER) in mammalian cells. Using calcein and fluorescently labelled lactoferrin encapsulated in fusogenic liposomes we found that the cargo uses a microtubule‐based pathway with ER delivery. Endocytic uptake of the lipid vesicles was cholesterol dependent in all cell lines tested, including the caveolin‐1‐deficient human hepatoma 7 cell line. The ligand was transported in non‐caveosome organelles requiring acidic pH for maturation, but able to escape the lysosomal route. These organelles were not recycling endosomes either, as shown by the lack of co‐localization with recycling transferrin. Co‐localization with the ER‐tracker, orange fluorescent protein with KDEL signal retention and cholera toxin in live microscopy revealed an ER distribution of the fluorescent ligand. Brefeldin A, which prevents Golgi‐dependent retrograde trafficking, does not disrupt the cargo delivery to the ER. This new endocytic pathway making use of acidic endosome‐like organelles is an alternative to the reported SV40 caveolae pathways. Exploiting a cellular route linking the cell surface to the ER, fusogenic liposomes may become efficient drug delivery vehicles for ER stress and diseases.