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-Tf) achieved significantly greater transfection efficiency of pApoE2 and pGFP in neuronal cells (p < 0.0001) compared to single-modified (RDP or Tf) 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.
