Opposing Roles of Syndecan-1 and Syndecan-2 in Polyethyleneimine-mediated Gene Delivery

Abstract

Polyethyleneimines (PEIs) are efficient non-viral vectors for gene transfer. Heparan sulfate proteoglycans have been proposed to be the cell-surface receptors for PEI⅐DNA complexes (polyplexes). Here, we investigated if syndecan-1 (SDC1) and syndecan-2 (SDC2) are involved in PEI-mediated transfection. Following addition of polyplexes to HEK293 cells, green fluorescent protein-tagged SDCs rapidly formed clusters with PEI that were dependent of lipid raft integrity. However, although SDC1 overexpression slightly enhanced PEI-mediated gene expression, SDC2 dramatically inhibited it. Confocal microscopy analysis showed that SDC1⅐polyplex endocytosis occurred within minutes after addition of polyplexes, whereas SDC2⅐polyplex endocytosis took hours. Expression of SDC1 cytoplasmic deletion mutants revealed that the SDC1 cytoplasmic tail is required for gene expression, but not for clustering or endocytosis, whereas overexpression of SDC1/SDC2 chimeras showed that the SDC2 ectodomain is responsible for the inhibitory effect on gene transfer. This study provides evidence that SDCs may have opposing effects on PEI-mediated transfection.

Syndecan-4 promotes cytokinesis in a phosphorylation-dependent manner

“…Because of the diverse stainings of SDC4 in the midbody region the distribution of the phosphorylated and non-phosphorylated forms was studied by using green fluorescent protein (GFP)-tagged mutants. The plausible C-terminal fusion of GFP did not provide adequate results in our tests contrary to the published data [28], thus GFP was inserted into the juxtamembrane region of the extracellular domain to avoid the interference with the natural interacting partners of the cytoplasmic domain (Fig. 3a).…”

Polyethylenimine Is a Strong Inhibitor of Human Papillomavirus and Cytomegalovirus Infection

“…In mammals, syndecans and glypicans constitute the predominant cell surface HSPGs (5,20). Recently, it has been shown that PEI-DNA complexes bind to syndecans 1 and 2, inducing clustering of these syndecans as an initial step of internalization (42). Depending on the type of syndecan, endocytosis of PEI-DNA complexes follows different kinetics.…”

High-Throughput Turbidimetric Screening for Heparin-Neutralizing Agents and Low-Molecular-Weight Heparin Mimetics

“…6). PEI is reported to have GAG-binding property, and utilized as an HS proteoglycan-mediated DNA transfection agent 15) and a GAG stain for histology. 16) The heparin-inhibiting property of compound 1 was similar to that of PEI (Fig.…”

“…We thus compared the heparin-neutralizing activity of 1 with that of PEI, which is a polyamine known to interact with heparin/HS proteoglycans, 15,16) by the collagen fibril formation assay (Fig. 7).…”