Chronic obstruction pulmonary disease (COPD) is a major cause of morbidity and mortality across the world. COPD is currently the fourth leading cause of death in the world and is predicted to become the third leading cause of chronic illness and death worldwide by 2030. There are several therapeutic strategies to reduce COPD symptoms and complications such as; bronchodilator medications, antibiotics, inhaled corticosteroids and rehabilitation. However, none of the available pharmacological or non-pharmacological treatments for COPD have been shown to delay or correct long-term defects in lung function. Small nucleic acids such as non-coding RNA (ncRNA) and interference microRNA (miRNA) have recently gained attention as a new class of therapeutics for various genetic diseases. Modulation of miRNA expression and function represents a promising strategy for therapeutic intervention in disorders such as inflammatory lung disease including COPD. In this study the aim was to design, formulate and characterise polymeric nanoparticles (NPs) containing miR-146a. This was followed by spray-dying using L-leucine and mannitol to prepare dry powder nanocomposite microparticles (NCMPs) for pulmonary delivery. Anionic and cationic poly (glycerol adipate-co- ω-pentadecalactone), (PGA-co-PDL), NPs were produced using poly (vinyl alcohol) and dioleoyltrimethylammoniumpropane (DOTAP) respectively. The particle size of the anionic NPs was 266.10±20.80 nm and the incorporation of DOTAP resulted in NPs of 244.80±4.40 nm at 15 % DOTAP concentration. The zeta potential (ZP) of 15 % DOTAP NPs was +14.8±0.26 mV. Fluorescently labelled synthetic miRNA (miR-146a) was adsorbed onto the surface of the optimum 15 % DOTAP NPs. The cell viability studies indicated that over 65 % of A549 cells remained viable after 24 h exposure to cationic NPs at a concentration of 1.25 mg/ml. The spray drying process was optimised to produce NCMPs with recovered NPs of 409.7±10.05 nm, yield of 86.05±15.01 % and low moisture content 2.02±0.03 %. The NCMPs produced had a spherical shape and corrugated surface. The in vitro aerosolisation analysis showed a mass mean aerodynamic diameters (MMAD) of less than 6 μm indicating the NCMPs would be deposited in the middle to deep lung region and a fine particle fraction (FPF) of 51.33±2.90 %. Internalisation of miR-146a loaded cationic NPs was observed in A549 cell lines using both fluorescence and confocal microscopy. The miR146a delivered to A549 cells as miR-146a-NPs and miR146a-NCMPs had a dose dependent reduction on target gene repression; interleukin 1 receptor-associated kinase (IRAK1) expression to 40 % and TNF receptor-associated factor (TRAF6) expression to over 20 %. Moreover, the miR-146a biological activity was maintained after spray drying. These findings demonstrate the promise of miR-146a-NPs/NCMPs as a dry powder pulmonary for the treatment of COPD, protecting miR-146a from degradation and enzymatic activity in the lung airways.
| Identifer | oai:union.ndltd.org:bl.uk/oai:ethos.bl.uk:755787 |
| Date | January 2018 |
| Creators | Mohamed, A. A. |
| Contributors | Saleem, I. ; Hutcheon, G. ; Ross, K. |
| Publisher | Liverpool John Moores University |
| Source Sets | Ethos UK |
| Detected Language | English |
| Type | Electronic Thesis or Dissertation |
| Source | http://researchonline.ljmu.ac.uk/9376/ |
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