title: Coating nanocarriers with hyaluronic acid facilitates intravitreal drug delivery for retinal gene therapy.
abstract: Retinal gene therapy could potentially affect the lives of millions of people suffering from blinding disorders. Yet, one of the major hurdles remains the delivery of therapeutic nucleic acids to the retinal target cells. Due to the different barriers that need to be overcome in case of topical or systemic administration, intravitreal injection is an attractive alternative administration route for large macromolecular therapeutics. Here it is essential that the therapeutics do not aggregate and remain mobile in the vitreous humor in order to reach the retina. In this study, we have evaluated the use of hyaluronic acid (HA) as an electrostatic coating for nonviral polymeric gene nanomedicines, p(CBA-ABOL)/pDNA complexes, to provide them with an anionic hydrophilic surface for improved intravitreal mobility. Uncoated polyplexes had a Z-averaged diameter of 108nm and a zeta potential of +29mV. We evaluated polyplexes coated with HA of different molecular weights (22kDa, 137kDa and 2700kDa) in terms of size, surface charge and complexation efficiency and noticed their zeta potentials became anionic at 4-fold molar excess of HA-monomers compared to cationic monomers, resulting in submicron ternary polyplexes. Next, we used a previously optimized ex vivo model based on excised bovine eyes and fluorescence single particle tracking (fSPT) microscopy to evaluate mobility in intact vitreous humor. It was confirmed that HA-coated polyplexes had good mobility in bovine vitreous humor, similar to polyplexes functionalized with polyethylene glycol (PEG), except for those coated with high molecular weight HA (2700kDa). However, contrary to PEGylated polyplexes, HA-coated polyplexes were efficiently taken up in vitro in ARPE-19 cells, despite their negative charge, indicating uptake via CD44-receptor mediated endocytosis. Furthermore, the HA-polyplexes were able to induce GFP expression in this in vitro cell line without apparent cytotoxicity, where coating with low molecular weight HA (22kDa) was shown to induce the highest expression. Taken together our experiments show that HA-coating of nonviral gene complexes is an interesting approach towards retinal gene therapy by intravitreal administration. To our knowledge, this is the first time electrostatic HA-coating of polyplexes with different molecular weights has been evaluated in terms of their suitability for intravitreal delivery of therapeutic nucleic acids towards the retina.
authors: Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium; Center for Nano-and Biophotonics (NB-Photonics), Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium. Electronic address: Thomas.Martens@Ugent.be.
authors: Thomas F
authors: TF
authors: Martens
authors: Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium.
authors: Katrien
authors: K
authors: Remaut
authors: EPFL STI IBI-STI LBEN, BM 2138 (Bâtiment BM), Station 17, CH-1015 Lausanne, Switzerland.
authors: Hendrik
authors: H
authors: Deschout
authors: Department of Biomedical Chemistry, MIRA Institute for Biomedical Technology and Technical Medicine, Faculty of Science and Technology, University of Twente, P.O. Box 217, 7500 AE Enschede, The Netherlands.
authors: Johan F J
authors: JF
authors: Engbersen
authors: Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, P.O. Box 80.082, 3508 TB Utrecht, The Netherlands.
authors: Wim E
authors: WE
authors: Hennink
authors: Department of Pharmaceutics, Utrecht Institute for Pharmaceutical Sciences (UIPS), Utrecht University, P.O. Box 80.082, 3508 TB Utrecht, The Netherlands.
authors: Mies J
authors: MJ
authors: van Steenbergen
authors: Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium.
authors: Jo
authors: J
authors: Demeester
authors: Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium. Electronic address: Stefaan.Desmedt@Ugent.be.
authors: Stefaan C
authors: SC
authors: De Smedt
authors: Laboratory of General Biochemistry and Physical Pharmacy, Faculty of Pharmaceutical Sciences, Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium; Center for Nano-and Biophotonics (NB-Photonics), Ghent University, Ottergemsesteenweg 460, 9000 Ghent, Belgium. Electronic address: Kevin.Braeckmans@Ugent.be.
authors: Kevin
authors: K
authors: Braeckmans
mesh_terms: D002460:Cell Line; D004247:DNA / Q000008:administration & dosage / Q000737:chemistry*; D015316:Genetic Therapy; D006801:Humans; D018960:Hyaluronan Receptors / Q000378:metabolism; D006820:Hyaluronic Acid / Q000737:chemistry*; D058449:Intravitreal Injections; D050997:Nanomedicine; D010957:Plasmids; D011108:Polymers / Q000737:chemistry; D012160:Retina / Q000378:metabolism
chemical_list: C497483:CD44 protein, human; D018960:Hyaluronan Receptors; D011108:Polymers; D006820:Hyaluronic Acid; D004247:DNA
keywords: Hyaluronic acid; Intravitreal; Molecular weight; Polyplexes; Retinal gene delivery