Nasal Administration of Cationic Nanoemulsions as Nucleic Acids Delivery Systems Aiming at Mucopolysaccharidosis Type I Gene Therapy.

PURPOSE: This study demonstrates the nasal administration (NA) of nanoemulsions complexed with the plasmid encoding for IDUA protein (pIDUA) as an attempt to reach the brain aiming at MPS I gene therapy. METHODS: Formulations composed of DOPE, DOTAP, MCT (NE), and DSPE-PEG (NE-PEG) were prepared by high-pressure homogenization, and assessed in vitro on human fibroblasts from MPS I patients and in vivo on MPS I mice for IDUA production and gene expression. RESULTS: The physicochemical results showed that the presence of DSPE-PEG in the formulations led to smaller and more stable droplets even when submitted to dilution in simulated nasal medium (SNM). In vitro assays showed that pIDUA/NE-PEG complexes were internalized by cells, and led to a 5% significant increase in IDUA activity, besides promoting a two-fold increase in IDUA expression. The NA of pIDUA/NE-PEG complexes to MPS I mice demonstrated the ability to reach the brain, promoting increased IDUA activity and expression in this tissue, as well as in kidney and spleen tissues after treatment. An increase in serum IL-6 was observed after treatment, although with no signs of tissue inflammatory infiltrate according to histopathology and CD68 assessments. CONCLUSIONS: These findings demonstrated that pIDUA/NE-PEG complexes could efficiently increase IDUA activity in vitro and in vivo after NA, and represent a potential treatment for the neurological impairment present in MPS I patients.

Optimization of alginate microcapsules containing cells overexpressing α-l-iduronidase using Box-Behnken design.

Mucopolysaccharidosis type I (MPS I) is an autosomal recessive disease caused by deficiency of α-l-iduronidase (IDUA), which results in the lysosomal accumulation of glycosaminoglycans (GAG) leading to widespread clinical manifestations. The microencapsulation of IDUA overexpressing recombinant cells has been considered as a promising strategy for the treatment of MPS I. This study aimed at the optimization of alginate microcapsules containing recombinant BHK (Baby Hamster Kidney) cells (rBHK) overexpressing IDUA produced by electrostatic extrusion technique. The alginate microcapsule (MC-A) optimization study was carried out by means of an experimental Box-Behnken Design that allowed the simultaneous evaluation of the influence of voltage (kV), alginate/cell suspension flow (mL/h), and alginate concentration (%) on size and IDUA activity. The optimal conditions of voltage (10kV), flow (25mL/h), and alginate concentration (1.3%) made possible to obtain the smallest microcapsules showing the highest IDUA activity. After optimization, the microcapsules were sequentially coated with PLL and alginate (MC-APA) to increase their stability. MC-A and MC-APA presented monodisperse populations (span<1.22) with an average diameter of less than 350µm. The coating increased the mechanical stability of MC-APA by about 6-fold and modulated the permeability to the enzyme. Surface analyzes of MC-APA showed the presence of PLL bands, suggesting that the last alginate layer appears to have only partially coated the PLL. After 30days of subcutaneous implantation of the MC-APA microcapsules containing rBHK cells in a MPS I murine model, a significant increase in IDUA activity was observed in the skin near the implant. Histological analysis revealed an inflammatory infiltrate at the application site, which did not prevent the release of the enzyme under the conditions evaluated. Taken together, the overall results demonstrate the feasibility of MC-APA as a potential alternative for local treatment of MPS I.

Cationic Nanoemulsions as a Gene Delivery System: Proof of Concept in the Mucopolysaccharidosis I Murine Model.

Mucopolysaccharidosis I (MPS I) is an autosomal recessive lysosomal storage disease due to deficient a-L-iduronidase (IDUA) activity. It results in the accumulation of the glycosaminoglycans (GAGs) heparan and dermatan sulfate and leads to several clinical manifestations. This study describes the use of cationic nanoemulsions as a non-viral carrier for the plasmid named pIDUA, which has the gene that encodes for the IDUA enzyme. Cationic nanoemulsions, composed by a medium chain triglycerides oil core stabilized by DOTAP, DOPE and DSPE-PEG, were prepared by high pressure homogeneization. pIDUA was complexed with nanoemulsions in the end of manufacturing process. Physicochemical properties of complexes were influenced by the charge ratio used. From a charge ratio of +2/-, it was observed a total complexation of pIDUA with formulation as well as a protection of plasmid against DNAse I digestion. In vitro assay in fibroblasts of one MPS I patient presented greater and significant trasfection efficiency for pIDUA complexed to formulation in the +4/- charge ratio. This formulation was administered via the tail vein and the portal vein. Animals were compared to untreated MPS I mice. Transfection efficiency was measured as IDUA enzyme activity. After intravenous administration, IDUA activity was significantly higher in lungs and liver. The set of results shows the formulation obtained at the +4/- charge ratio as a promising non-viral gene delivery system, once showed increased enzyme activity both in vitro and in vivo.

PEGylated cationic nanoemulsions can efficiently bind and transfect pIDUA in a mucopolysaccharidosis type I murine model.

Mucopolysaccharidosis type I (MPS I) is an autosomal disease caused by alpha-L-iduronidase deficiency. This study proposed the use of cationic nanoemulsions as non-viral vectors for a plasmid (pIDUA) containing the gene that codes for alpha-L-iduronidase. Nanoemulsions composed of medium chain triglycerides (MCT)/1,2-dioleoyl-sn-glycero-3-phosphoethanolamine (DOPE)/1,2-dioleoyl-sn-glycero-3-trimethylammonium propane (DOTAP)/1,2-distearoyl-sn-glycero-3-phosphoethanolamine-N-[amino(polyethylene glycol)-2000] (DSPE-PEG) were prepared by high pressure homogenization. Formulations were prepared by the adsorption or encapsulation of preformed pIDUA-DOTAP complexes into the oil core of nanoemulsions at different charge ratios. pIDUA complexed was protected from enzymatic degradation by DNase I. The physicochemical characteristics of complexes in protein-containing medium were mainly influenced by the presence of DSPE-PEG. Bragg reflections corresponding to a lamellar organization were identified for blank formulations by energy dispersive X-ray diffraction, which could not be detected after pIDUA complexation. The intravenous injection of these formulations in MPS I knockout mice led to a significant increase in IDUA activity (fluorescence assay) and expression (RT-qPCR) in different organs, especially the lungs and liver. These findings were more significant for formulations prepared at higher charge ratios (+4/-), suggesting a correlation between charge ratio and transfection efficiency. The present preclinical results demonstrated that these nanocomplexes represent a potential therapeutic option for the treatment of MPS I.

Adsorption of antisense oligonucleotides targeting malarial topoisomerase II on cationic nanoemulsions optimized by a full factorial design.

Cationic nanoemulsions have been recently considered as potential delivery systems for oligonucleotides (ON) targeting Plasmodium falciparum topoisomerase II gene. This study is aiming to select the best composition of nanoemulsions intended to ON adsorption by means of a 2(3) full factorial design. Based on their physicochemical properties, two formulations were selected for further studies, both composed by medium chain triglycerides, egg-lecithin, and either oleylamine (OA) or 1,2-dioleoyl-3-trimethylammonium-propane (DOTAP). Adsorption isotherms of phosphodiester or phosphorothioate ON on the optimized nanoemulsions were obtained (ultrafiltration/centrifugation procedure). They showed a significant higher amount of ON adsorbed on DOTAP nanoemulsion when compared to the OA ones. The Langmuir adsorption model provides the most satisfactory representation of the adsorption data. Evidence of ON adsorption could be detected by the inversion of the ζ-potential and the morphology of the oil droplets examined by transmission electron microscopy. Preliminary results regarding hemolytic effect and P. falciparum survival after exposure to optimized formulations were related to their physicochemical properties and in vitro effects. The overall results showed the potential of the optimized nanoemulsions as non-viral carriers for antisense ON against malaria parasites.