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  • Novel RGD-lipid conjugate-modified liposomes for enhancing siRNA delivery in human retinal pigment epithelial cells.

Novel RGD-lipid conjugate-modified liposomes for enhancing siRNA delivery in human retinal pigment epithelial cells.

International journal of nanomedicine (2011-12-01)
Cheng-Wei Chen, Da-Wen Lu, Ming-Kung Yeh, Chia-Yang Shiau, Chiao-Hsi Chiang
ABSTRACT

Human retinal pigment epithelial cells are promising target sites for small interfering RNA (siRNA) that might be used for the prevention and/or treatment of choroidal neovascularization by inhibiting the expression of angiogenic factor; for example, by downregulating expression of the vascular endothelial growth factor gene. A novel functional lipid, DSPE-PEG-RGD, a Arg(R)-Gly(G)-Asp(D) motif peptide conjugated to 1, 2-distearoyl-sn-glycero-3-phosphoethanolamine- N-[maleimide (polyethylene glycol)-2000], was synthesized for the preparation of siRNA-loaded RGD-PEGylated liposomes to enhance uptake of encapsulated siRNA in retinal pigment epithelial cells. Various liposomes, with 1 mol% and 5 mol% PEGylated lipid or 1 mol% and 5 mol% RGD-PEGylated lipid, were fabricated. Characterization of the liposomes, including siRNA entrapment efficiency, average particle size and ζ-potential, were determined to be as follows: >96%, 129.7 ± 51 to 230.7 ± 60.7 nm, and 17.3 ± 0.6 to 32 ± 1.3 mV, respectively. For the in vitro retinal pigment epithelial cell studies, the RGD-PEGylated liposomes had high delivery efficiency with siRNA delivery, about a four-fold increase compared with the PEGylated liposomes. Comparison of the various liposomes showed that the 1 mol% RGD-modified liposome had less cytotoxicity and higher siRNA delivery efficiency than the other liposomes. The antibody blocking assay confirmed that uptake of the 1 mol% RGD-PEGylated liposome was via integrin receptor- mediated endocytosis in retinal pigment epithelial cells. The results of this study suggest that RGD-PEGylated liposomes might be useful for siRNA delivery into retinal pigment epithelial cells by integrin receptor-medicated endocytosis.

MATERIALS
Product Number
Brand
Product Description

Sigma-Aldrich
1,2-Distearoyl-sn-glycero-3-phosphoethanolamine, ≥99%
Sigma-Aldrich
NanoFabTx- PEG-RGD Lipid Mix, for synthesis of PEGylated RGD-functionalized liposomes
Supelco
α-Cyano-4-hydroxycinnamic acid, matrix substance for MALDI-MS, ≥99.0% (HPLC)
Sigma-Aldrich
α-Cyano-4-hydroxycinnamic acid, 99%
Sigma-Aldrich
α-Cyano-4-hydroxycinnamic acid, ≥98% (TLC), powder
Avanti
DSPE-RGD, Avanti Research - A Croda Brand 870295P, powder