Dual-modified Liposomes Encapsulating Nucleic Acids (pApoE2 or pGFP) for Transport Studies Across a Hydrocortisone-enhanced In Vitro Blood-brain Barrier Model for CNS Therapeutic Screening.

PURPOSE

The study assessed dual-modified liposomes for delivering pApoE2 and pGFP across an in vitro blood-brain barrier (BBB) model supplemented with hydrocortisone (HC), evaluating their transfection efficiency in neuronal cells across the BBB and the impact of hydrocortisone on BBB integrity.

METHODS

An in vitro BBB model was developed using brain endothelial cells (bEnd.3) co-cultured with primary astrocytes in a transwell system. Hydrocortisone's effect on BBB integrity was assessed via transepithelial electrical resistance (TEER), permeability and transport studies. Liposomes, modified with cell-penetrating peptide-RDP and Transferrin, encapsulating pApoE2 or pGFP-chitosan polyplex, were evaluated for neuronal cell transfection after crossing the BBB.

RESULTS

The BBB models supplemented with 150 nM HC showed a significant increase in TEER values compared to monolayers (p < 0.0001) and co-culture BBB models without HC supplementation (p < 0.01), indicating enhanced BBB integrity. Permeability assays demonstrated reduced sodium fluorescein translocation across the 150 nM hydrocortisone-supplemented BBB models compared to monolayers (p < 0.001) and co-culture models without HC supplementation (p < 0.05). Liposomes exhibited good characteristics and efficient encapsulation of pApoE2 or pGFP-chitosan polyplex, and successfully crossed the developed BBB model. Dual-modified liposomes (RDP-T) achieved significantly greater transfection efficiency of pApoE2 and pGFP in neuronal cells (p < 0.0001) compared to single-modified (RDP or T) and plain liposomes.

CONCLUSIONS

Hydrocortisone enhanced the BBB properties of the in vitro model, making it more representative of the in vivo BBB. Dual-modified liposomes demonstrated superior efficacy in delivering genetic materials across the BBB, providing a promising approach for therapeutic interventions in neurodegenerative diseases like Alzheimer's.