View Abstract

A7204 - Modulation of the Notch Pathway in Adult Mouse Airways by Antisense Oligonucleotides
Author Block: M. Carrer, J. R. Crosby, K. E. Shannon, S. S. Damle, S. G. Kuntz, B. P. Monia, C. E. Hart, T. R. Grossman; Antisense Drug Discovery, Ionis Pharmaceuticals Inc., Carlsbad, CA, United States.
RATIONALE: Aberrant goblet cells metaplasia characterizes multiple respiratory disorders, including asthma and chronic obstructive pulmonary disease, and drives excessive mucus production with insufficient mucus clearance. Notch signaling within the respiratory epithelium appears to play a central role in controlling the balance of mucus-producing club and goblet cells, and mucus-clearing ciliated cells. Previous work by Lafkas et al. showed that blocking the Notch ligands JAG1 and JAG2 results in the direct conversion of club cells to ciliated cells. Our goal is to better understand the therapeutic potential of promoting the transdifferentiation of mucus-secreting cells into ciliated cells. Ultimately we hope to restore the normal mucociliary clearance in diseased airways through therapeutically controlled remodeling of the lung. METHODS: Second generation chemically modified ASOs targeting the various Notch receptors and ligands were designed and characterized. We administered ASOs by orotracheal delivery in either normal mice or mice that received house dust mite (HDM). We evaluated the effect of ASO treatment on cell transdifferentiation, mucus secretion and respiratory function in the murine lung using real time RT-PCR, 3’ tag RNA-seq, whole-body plethysmography, and histological analysis. RESULTS: Local administration of ASOs for various Notch components results in a significant reduction of the target mRNAs in the murine lung. ASO-mediated knockdown of Jag1 leads to the depletion of secretory-cell markers and the concomitant enrichment of ciliated-cell markers in the adult murine airway epithelium. Furthermore, knockdown of Jag1 expression by ASOs in the HDM mouse model of asthma leads to goblet cell transdifferentiation, reduced mucus secretion and improved lung function. Marker gene expression analysis and genome-wide 3’ tag RNA-seq analysis of samples from mice treated with different ASOs confirmed the role of Jag1 and Notch signaling in the adult lung. CONCLUSIONS: Our work highlights the role of Notch signaling in controlling the fate of ciliated and mucus-secreting cells in the adult murine airways. We show that in a disease model of asthma, Jag1 inhibition through local ASO administration leads to the remodeling of the lung epithelium and improvement of lung function. Our molecular and histological analysis suggest that this is a result of goblet cell transdifferentiating into ciliated cells. Since goblet cell metaplasia and excessive mucus production is a common basis for many lung pathologies, we believe ASO-mediated inhibition of Jag1 could provide a good therapeutic option for multiple respiratory disorders.