Biology subjects

McCarron, A.

Publications and source records attributed to McCarron, A..

4 recordsLinked to original sources

bioRxiv2025

Evaluating an In Vivo Oxidative Stress sensor in cystic fibrosis rat epithelial tissues

We have developed a novel biosensing device that can detect the real-time, dynamic state of in vivo oxidative status (IVOS) in living systems. Oxidative stress is a well-established condition in CF animal models and humans. Elevated oxidative stress conditions are associated with excessive inflammatory responses from neutrophils that result in fibrotic tissue formation. As such, numerous clinical and preclinical studies suggest that elevated oxidative stress, combined with the heightened pro-inflammatory milieu observed in CF phenotypes, likely increases susceptibility to recurrent infection-inflammation cycles. We aimed to use the IVOS sensor to characterise oxidative environmental differences in wildtype, CF Phe508del and CFTR knockout rat epithelial tissues including the lungs, trachea, nasal mucosa, and oesophagus. Our results revealed no significant differences in the baseline redox balance between wildtype, Phe508del and knockout rat tissues, however when we looked at short term fluctuations in redox status using the ratio of the root mean squared of successive differences (RMSSD) to the normalised mean IVOS arbitrary units, we saw significantly elevated fluctuations in the redox status in the bronchi of Phe508del rats compared to wildtype rats, indicating a lower steady-state oxidative environment combined with large transient oxidative events.

biophysics↗

bioRxiv2025

Gene-Corrected Basal Cells Restore CFTR In Vitro; Transplants Regenerate Epithelium in a Preclinical Sinus Model

BackgroundCystic fibrosis (CF) is caused by mutations in the CFTR gene, leading to epithelial dysfunction and progressive lung disease. Although CFTR modulators have transformed care, [~]10% of people with CF remain without effective therapy. Durable, mutation-agnostic approaches are urgently needed. MethodWe used a lentiviral (LV) vector to deliver wild-type CFTR to airway basal cells derived from 13 paediatric CF participants with a range of genotypes. Transduced cells were assessed for transgene expression, epithelial differentiation, and CFTR function using air-liquid interface (ALI) cultures. Separately, to evaluate regenerative capacity in vivo, LVGFP-transduced rabbit airway basal cells were transplanted into the denuded nasal septum of healthy New Zealand white rabbits using a biocompatible scaffold. ResultsTransduced basal cells retained multilineage differentiation capacity, forming well-organized, pseudostratified epithelium with intact barrier function and ciliary activity. CFTR channel activity was restored to levels comparable to or exceeding those achieved with elexacaftor/tezacaftor/ivacaftor (ETI), including in individuals with nonsense mutations. Combined CFTR transduction plus ETI treatment showed additive benefit. In vivo, transplanted rabbit basal cells engrafted and differentiated to regenerate a mucociliary epithelium, with improved nasal potential difference and mucociliary clearance compared to scaffold-only controls. ConclusionOur study demonstrates that LV-mediated CFTR gene addition restores CFTR function in vitro across genotypes and supports epithelial regeneration in a clinically relevant animal airway model. This two-part platform offers a scalable path toward cell therapies for all people with CF and may have broader applications in upper airway epithelial repair.

cell biology↗

bioRxiv2025

A longitudinal evaluation of localised chronic Pseudomonas aeruginosa infection in cystic fibrosis rat models

Recurrent bacterial infections with Pseudomonas aeruginosa result in chronic airway inflammation, lung damage and eventual respiratory failure, and are the major cause of morbidity and mortality in people with cystic fibrosis (CF). Animal models are essential for understanding disease progression and assessing potential treatments in the presence of infection. Previously reported P. aeruginosa lung infection rodent models for CF research have some weakness, including acute infection rather than chronic, associated mortality, use of laboratory strains of P. aeruginosa and the use of non-CF rodents. The aim of this study was to create a localised P. aeruginosa infection in wildtype and two CF rat models, by delivering bacteria embedded agar beads using a miniature bronchoscope. The resulting infection was well tolerated by all animals of all genotypes with no mortality associated with the procedure or infection. Histologically the affected regions were localised to the right lung, with bronchopneumonia present. Bacteria persisted for 9 weeks (63 days) in all genotypes, with lung function changes observed by day 63 of the infection.

pathology↗

bioRxiv2025

CFTR High Expresser BEST4+ cells are pH-sensing neuropod cells: new implications for intestinal physiology and Cystic Fibrosis disease

Single-cell RNA sequencing (scRNA-seq) studies identified a novel subpopulation of epithelial cells along the rostrocaudal axis of human intestine specifically marked by bestrophin 4 (BEST4) that are enriched for genes regulating pH, GPCR acid-sensing receptors, satiety, cGMP signaling, HCO3- secretion, ion transport, neuropeptides, and paracrine hormones. Interestingly, BEST4+ cells in the proximal small intestine express CFTR but have not been linked to the previously described CFTR High Expresser Cell (CHE) subpopulation in rat and human intestine. ScRNA-seq studies in rat jejunum identified CHEs and a gene expression profile consistent with human small intestinal BEST4+ and neuropod cells. Protein immunolocalization confirmed that CHEs express CFTR, BEST4, neuropod proteins, high levels of intracellular uroguanylin (UGN), guanylyl cyclase-C (GC-C), and the proton channel otopetrin 2 (OTOP2), and display long basal processes connecting to neurons. OTOP2, GC-C, and CFTR traffic robustly into the apical domain of CHEs in response to acidic luminal conditions, indicating their roles in luminal pH regulation. In the {Delta}F508 cystic fibrosis (CF) rat jejunum, the loss of apical CFTR did not affect BEST4 protein expression in CHEs. However, there was an increased abundance of CHE cells in the {Delta}F508 rat jejunum compared to wild-type animals. Furthermore, {Delta}F508 rat CHEs expressed higher levels of GC-C at the apical domain compared to wild-type. These data implicate CHEs in intestinal CF disease pathogenesis. NEW & NOTEWORTHYThis is the first study to identify CFTR High Expresser cells in the rat small intestine as neuropod cells capable of sensing and responding to luminal pH. This study also provides the first characterization of CFTR and relevant mRNA and proteins in CHEs in CF rat models that provide insights into the significance of CHEs to CF intestinal disease.

physiology↗