(602) Optimization of CFTR^G551D Ferret Model for Early Synchronized Lung Microbial Colonization

Thursday, November 3, 2022

12:00 PM – 12:40 PM ET

Presenting Author(s)

Allison Lacina (she/her/hers)

Research Assistant
Anatomy & Cell Biology, U of Iowa
Iowa City, Iowa, United States

Co-Author(s)

AS

Amanita Shonka

United States
YZ

Yulong Zhang

United States
IE

Immaculate Edwin

United States
EN

Emily Nugent

United States
IA

Idil Apak

United States
EC

Erin Corrigan

United States
Xingshen Sun, PhD

Research Assistant Professor of Anatomy and Cell Biology
The University of Iowa, Iowa, United States
DL

Dominque H. Limoli

Assistant Professor
The University of Iowa, United States
JE

John F. Engelhardt

Professor
Department of Anatomy and Cell Biology, University of Iowa, Iowa City, Iowa
Iowa City, Iowa, United States
DB

Doug J. Bartels, PhD

Executive Director
National Ferret Center
Iowa City, Iowa, United States

Background: Preclinical models of cystic fibrosis (CF) lung disease are critical for advancing novel therapies. The creation of modulator dependent CFTR^G551D ferrets was a major milestone, which enabled further optimization and study of CF lung disease and CF microbiome evolution in this report.

Methods: Ferrets harboring a potentiator-responsive CFTR^G551D mutation were enrolled in longitudinal studies of the lung microbiome. CFTR potentiator was removed at various ages up to 21 months, but the primary synchronized cohort removed potentiator at 3-months-old. Surveillance of oral microbiome was done with use of upper tracheal swabbing, and oral rinses with saline. The lung microbiome was monitored with bronchoalveolar lavage fluid (BALF) and lung tissue lysates. Culturing was done aerobically and anaerobically on blood agar and pseudomonas isolation agar. Identification of individual colonies was completed with the Bruker MALDI-TOF Biotyper.

Results: Ferrets removed from CFTR potentiator later in life ( >6 months of age) had slow progression of lung disease and the majority did not acquire later stage CF lung microbiome such as Pseudomonas aeruginosa (Pa), one exception was a 963 days-old ferret that was chronically colonized with mucoid Pa. To synchronize and accelerate colonization into months, not years, we implemented passive methods to utilize the naturally occurring oral microbiome of the ferrets to initiate lung colonization. To synchronize cohorts, co-housing and shared water bottles were implemented. In a subset of ferrets the oral microbiome from that individual ferret was aspirated into the trachea and lung. Significant CF lung disease was observed as early as 4 months after removal of CFTR modulator in this younger cohort that were removed from modulator at 3 months old. A subset of the late adolescent CF ferrets at ~7 months of age presented with: 1) thick dehydrated mucus while performing bronchoscopy, 2) colony forming units > 10⁵ CFU/mL in BALF, 3) predominant CF associated microbiome such as Pseudomonas, Staphylococcus, and Streptococcus chronically colonizing the lung. Other factors not unfamiliar to the CF community also appear to impact colonization, such as a minor viral respiratory pathogen (not Coronavirus or Influenza), that led to only sneezing in the non-CF ferrets but led to exacerbations, pyrexia and secondary bacterial pneumonia in the CF ferrets off of CFTR modulator.

Conclusions: Advances in our ability to rear CFTR^G551D ferrets off CFTR modulator, combined with a variety of methods to expose CF ferrets to environmental and endemic microflora enabled production of more synchronized cohorts of CF study ferrets with lung disease. The presence of thick mucus, inflammation, and higher titer microbial lung colonization will be invaluable for answering critical preclinical therapeutic delivery and efficacy questions for novel therapeutics in a diseased CF lung.

Acknowledgements:

References:

(602) Optimization of CFTRG551D Ferret Model for Early Synchronized Lung Microbial Colonization

Presenting Author(s)

Co-Author(s)

(602) Optimization of CFTR^G551D Ferret Model for Early Synchronized Lung Microbial Colonization