title: Development of PEGylated PLGA nanoparticle for controlled and sustained drug delivery in cystic fibrosis.
abstract: BACKGROUND
  The mutation in the cystic fibrosis transmembrane conductance regulator (CFTR) gene results in CF. The most common mutation, ΔF508-CFTR, is a temperature-sensitive, trafficking mutant with reduced chloride transport and exaggerated immune response. The ΔF508-CFTR is misfolded, ubiquitinated, and prematurely degraded by proteasome mediated- degradation. We recently demonstrated that selective inhibition of proteasomal pathway by the FDA approved drug PS-341 (pyrazylcarbonyl-Phe-Leuboronate, a.k.a. Velcade or bortezomib) ameliorates the inflammatory pathophysiology of CF cells. This proteasomal drug is an extremely potent, stable, reversible and selective inhibitor of chymotryptic threonine protease-activity. The apprehension in considering the proteasome as a therapeutic target is that proteasome inhibitors may affect proteostasis and consecutive processes. The affect on multiple processes can be mitigated by nanoparticle mediated PS-341 lung-delivery resulting in favorable outcome observed in this study.
  
  
  RESULTS
  To overcome this challenge, we developed a nano-based approach that uses drug loaded biodegradable nanoparticle (PLGA-PEGPS-341) to provide controlled and sustained drug delivery. The in vitro release kinetics of drug from nanoparticle was quantified by proteasomal activity assay from days 1-7 that showed slow drug release from day 2-7 with maximum inhibition at day 7. For in vivo release kinetics and biodistribution, these drug-loaded nanoparticles were fluorescently labeled, and administered to C57BL6 mice by intranasal route. Whole-body optical imaging of the treated live animals demonstrates efficient delivery of particles to murine lungs, 24 hrs post treatment, followed by biodegradation and release over time, day 1-11. The efficacy of drug release in CF mice (Cftr-/-) lungs was determined by quantifying the changes in proteasomal activity (~2 fold decrease) and ability to rescue the Pseudomonas aeruginosa LPS (Pa-LPS) induced inflammation, which demonstrates the rescue of CF lung disease in murine model.
  
  
  CONCLUSIONS
  We have developed a novel drug delivery system to provide sustained delivery of CF "correctors" and "anti-inflammatories" to the lungs. Moreover, we demonstrate here the therapeutic efficacy of nano-based proteostasis-modulator to rescue Pa-LPS induced CF lung disease.
authors.affiliation: Department of Pediatric Respiratory Sciences, Johns Hopkins University School of Medicine, Baltimore, 21287, USA. nvij1@jhmi.edu.
authors.forename: Neeraj
authors.initials: N
authors.lastname: Vij
authors.forename: Taehong
authors.initials: T
authors.lastname: Min
authors.forename: Rhul
authors.initials: R
authors.lastname: Marasigan
authors.forename: Christopher N
authors.initials: CN
authors.lastname: Belcher
authors.forename: Steven
authors.initials: S
authors.lastname: Mazur
authors.forename: Hong
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authors.lastname: Ding
authors.forename: Ken-Tye
authors.initials: KT
authors.lastname: Yong
authors.forename: Indrajit
authors.initials: I
authors.lastname: Roy