Polyethylenimine-engineered respirable particles delivering a decoy oligonucleotide to NF-kB: a novel combination therapy for cystic fibrosis?

Due to the crucial role played by Nuclear Factor-kB (NF-kB) as lung inflammation mediator in cystic fibrosis (CF), an increasing interest of the research has been devoted to the development of new anti-inflammatory drugs able to distinctly interfere with NF-kB pathway. In particular, a promising strategy to inhibit NF-kB transcriptional activity is the use of decoy oligonucleotides (ODNs). However, translation of this approach in humans runs into the need of specifically tailored formulations for ODN inhalation, able to preserve ODN structural integrity and to slowly release it at the target site. This can be achieved by respirable biodegradable and biocompatible poly(lactic-co-glycolic acid) (PLGA) particles, the safety of which in the lung is supported by a growing body of literature. Nonetheless, imparting supplementary properties to the carrier may be crucial to increase its therapeutic potential in CF. In particular, the use of poly(ethyleneimine) (PEI) in ODN pulmonary delivery for CF treatment is very intriguing in the light of PEI osmotic nature, proved antibacterial properties toward Gram (-) bacteria, and potential mucolytic properties. The goal of our study is the development of a novel strategy for CF therapy based on the use of a decoy ODN against NF-kB (dec-ODN) delivered through multifunctional respirable powders containing poly(ethylenimine) (PEI), a cationic polymer with very attractive properties for CF treatment. Preliminary results We have already engineered poly(lactic-co-glycolic acid) (PLGA)-based porous particles (LPP) to meet several important criteria for the potential therapy of CF chronic inflammation based on the inhalation of dec-ODN that is i) achievement of dry powder formulations, currently regarded as the choice for ODN delivery to the lungs; ii) sustained release of dec-ODN; iii) aerosolization properties suitable for administration in rat lung. We have also investigated the effects of this formulation in human cultured CF cells stimulated with LPS from P. aeruginosa and demonstrated that dec-ODN LPP inhibited NF-B/DNA binding activity at lower concentrations and for longer time-frames in human cultured CF cells as compared to naked ODN. Concerning the in vivo potential of dec-ODN LPP, we have indications that rat intratracheally administered dec-ODN LPP inhibited bronchoalveolar neutrophil infiltration as well as IL-8 mRNA levels induced by LPS. Project description (experimental plan, methods, timing) We will first try to efficiently engineer LPP containing dec-ODN and PEI for widespread deposition in the lung and slow release of both molecules in situ. Special attention will be paid to exploit specific PEI functionalities, i.e effect on mucus viscosity and antimicrobial activity. Then, we will study the transfection efficiency and effects of optimized dec-ODN/PEI LPP on IL-6 and IL-8 mRNA levels and protein secretion in LPS-stimulated bronchial epithelial cells that exhibit CFTR mutations (IB3-1) and CFTR-corrected cells (S9). The results obtained will be compared with those achieved previously with LPP containing only dec-ODN. Furthermore, the effects of dec-ODN/PEI LPP on MUC2 gene expression in LPS-stimulated mucoepidermoid carcinoma cells (NCI-H292) expressing MUC2 gene will be investigated. Finally, we will try to understand the effects of the optimized dec-ODN/PEI LPP on rat leukocyte lung infiltration and IL-8 chemoattractant cytokine expression induced by LPS intratracheal nebulization. In case of positive results, a new combined therapy for controlling CF can be proposed.