Royal College of Surgeons in Ireland
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In vitro and in vivo assessment of PEGylated PEI for anti-IL-8/CxCL-1 siRNA delivery to the lungs.

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posted on 2021-01-05, 11:47 authored by Alan Hibbitts, Joanne M Ramsey, James BarlowJames Barlow, Ronan MacLoughlinRonan MacLoughlin, Sally-Ann CryanSally-Ann Cryan
Inhalation offers a means of rapid, local delivery of siRNA to treat a range of autoimmune or inflammatory respiratory conditions. This work investigated the potential of a linear 10 kDa Poly(ethylene glycol) (PEG)-modified 25 kDa branched polyethyleneimine (PEI) (PEI-LPEG) to effectively deliver siRNA to airway epithelial cells. Following optimization with anti- glyceraldehyde 3-phosphate dehydrogenase (GAPDH) siRNA, PEI and PEI-LPEG anti-IL8 siRNA nanoparticles were assessed for efficacy using polarised Calu-3 human airway epithelial cells and a twin stage impinger (TSI) in vitro lung model. Studies were then advanced to an in vivo lipopolysaccharide (LPS)-stimulated rodent model of inflammation. In parallel, the suitability of the siRNA-loaded nanoparticles for nebulization using a vibrating mesh nebuliser was assessed. The siRNA nanoparticles were nebulised using an Aerogen® Pro vibrating mesh nebuliser and characterised for aerosol output, droplet size and fine particle fraction. Only PEI anti-IL8 siRNA nanoparticles were capable of significant levels of IL-8 knockdown in vitro in non-nebulised samples. However, on nebulization through a TSI, only PEI-PEG siRNA nanoparticles demonstrated significant decreases in gene and protein expression in polarised Calu-3 cells. In vivo, both anti-CXCL-1 (rat IL-8 homologue) nanoparticles demonstrated a decreased CXCL-1 gene expression in lung tissue, but this was non-significant. However, PEI anti-CXCL-1 siRNA-treated rats were found to have significantly less infiltrating macrophages in their bronchoalveolar lavage (BAL) fluid. Overall, the in vivo gene and protein inhibition findings indicated a result more reminiscent of the in vitro bolus delivery rather than the in vitro nebulization data. This work demonstrates the potential of nebulised PEI-PEG siRNA nanoparticles in modulating pulmonary inflammation and highlights the need to move towards more relevant in vitro and in vivo models for respiratory drug development.


Science Foundation Ireland SFI 07/SRC/B1154.

SFI investigator (Grant 13/1A/1840)


Data Availability Statement

Supplementary materials available at


The original article is available at

Published Citation

Hibbitts AJ, Ramsey JM, Barlow J, MacLoughlin R, Cryan SA. In vitro and in vivo Assessment of PEGylated PEI for anti-IL-8/CxCL-1 siRNA delivery to the lungs. Nanomaterials. 2020;10(7):1248.

Publication Date

27 June 2020

PubMed ID



  • Chemistry
  • School of Pharmacy and Biomolecular Sciences

Research Area

  • Respiratory Medicine
  • Chemistry and Pharmaceutical Sciences
  • Biomaterials and Regenerative Medicine
  • Immunity, Infection and Inflammation




  • Published Version (Version of Record)

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