Therapeutic Peptide-Modified Gold Nanoparticles for the Treatment of Acute Lung Injury

Abstract

Purpose Acute lung injury (ALI) is a major cause of mortality after lung transplantation . Recent studies on protein kinase C (PKC) have demonstrated PKCδ to be an effective target for the treatment of ALI. We have developed a clinically applicable gold nanoparticle (GNP)-peptide hybrid that can specifically inhibit PKCδ signaling pathway . Methods and Materials δV1-1 therapeutic peptide and P2 and P4 stabilizing peptides were loaded on to 20 nm GNP surface via direct conjugation (50PKCi). GNP coated with P2 and P4 only were used as control (95P2P4-GNP). Physicochemical properties were examined to determine the stability and loading capacity of the nanoparticle . A lung transplant-simulated BEAS-2B cell culture model was used to evaluate the therapeutic efficacy of the GNP-Peptide hybrid, with cell viability , cytokine production and PKCδ phosphorylation as endpoints. To ensure the safety of the nano-formulation administered intravenously, hemolytic activity was examined in vitro. A pulmonary ischemia/reperfusion (I/R) rat model was used to test the therapeutic efficacy in vivo. Results The GNP-Peptide hybrid we fabricated showed good stability in water, 0.9% saline and serum, with 3408 peptides attached per GNP. In the cell culture model, treating BEAS-2B cells with 50PKCi significantly reduced IL-6 and IL-8 cytokine production after cold ischemic time (CIT) and decreased cell death in a dose dependent manner. 50PKCi also significantly inhibited PKCδ phosphorylation after CIT. We found 50PKCi to be safe to administer intravenously at all tested concentrations, although minor hemolysis was observed at high concentrations ( blood oxygenation and lung function parameters compared to 95P2P4-GNP administration. Conclusions We have successfully formulated a clinically applicable nano-particle with therapeutic potential to ameliorate lung injury and inflammation . The 50PKCi nano-formulation may also be useful for I/R-induced damage in other organs, such as myocardial infarction and stroke.