Oral Presentation Australasia Extracellular Vesicles Conference 2017

Proof-of-concept preclinical testing of amnion epithelial cell derived extracellular vesicles for interstitial lung fibrosis (#8)

Jean Tan 1 2 , Sin Nee Lau 1 , Siow Teng Chan 1 , Euan M Wallace 2 , Mohamed Saad 1 , Dandan Zhu 1 , Carla B Kim 3 , Rebecca Lim 1 2
  1. The Ritchie Centre, Hudson Institute of Medical Research, Clayton, Victoria, Australia
  2. Department of Obstetrics and Gynaecology, Monash University, Melbourne, VIC, Australia
  3. Boston Children's Hospital, Harvard Medical School, Boston, Massachusetts, USA

Background and rationale: The human amnion epithelial cells (hAECs) release extracellular vesicles (EVs) that reflect the pro-reparative properties of the hAECs. hAEC-EVs package immunomodulatory molecules such as HLA-G, and ligands associated with stem cell niche maintenance, such as Wnt5A. RNA-Seq analysis revealed that 8 miRNAs with reported anti-fibrotic effects were amongst the most abundant transcripts.

Aim: Since lung fibrosis is though to be perpetuated by stem cell attrition, we sought to evaluate the potential of hAEC-EVs to reverse lung fibrosis.

Methods: Eleven-to-twelve month old female C57Bl6 mice (n=6 per group) were challenged with bleomycin (0.15U/kg) and fibrosis allowed to develop. On the 14th day post challenge, either 10mg EVs resuspended in saline, or vehicle alone, was instilled intranasally. Mice were culled 28 days post challenge. Tissues were collected for histological analysis and endogenous lung stem cells (bronchioalveolar stem cells; CD31-, CD45-, EpCAM+, Sca1hi) were flow sorted for gene expression analysis using the Fluidigm Biomark HD.

Results: The hAEC-EVs reversed fibrosis to levels comparable to healthy controls and this was associated with a 50% reduction in myofibroblast activation (p<0.01). Coincident with these findings, we observed significant increase in the transcription of b-catennin, BMP4, Cyclin D1, FoxM1, NFATc1 and Sca-1 in the bronchioalveolar stem cells. When 3D organoids of the bronchioalveolar stem cells were cultured in the presence of the hAEC-EVs, we also observed a greater number of colonies (p<0.0001) where the average size of each colony type (alveolar, bronchiolar and mixed) was also greater than control organoids (p<0.01).

Conclusion: hAEC-EVs exert potent anti-fibrotic effects in aged mice challenged with bleomycin. This appears to be associated with their ability to either activate endogenous stem cells within the lung or protect the stem cell niche during injury.

Disclosure: RL and EMW are inventors on patents describing the methods, composition and application of the hAEC-EVs.