Zimmermann, N. | Search bioRxiv

bioRxiv2019

Heart Disease in a Mutant Mouse Model of Spontaneous Eosinophilic Myocarditis Maps to Three Highly Significant Loci

BackgroundHeart disease (HD) is the major cause of morbidity and mortality in patients with hypereosinophilic diseases. Due to a lack of adequate animal models, our understanding of the pathophysiology of eosinophil-mediated diseases with heart complications is limited. We have discovered a mouse mutant, now maintained on an A/J inbred background, that spontaneously develops hypereosinophilia in multiple organs. Cellular infiltration into the heart causes an eosinophilic myocarditis, with affected mice of the mutant line (i.e., A/JHD) demonstrating extensive myocardial damage and remodeling that leads to HD and premature death, usually by 15-weeks old. Maintaining the A/JHD line for many generations established that the HD trait was heritable and implied the mode of inheritance was not too complex. Backcross and intercross populations generated from mating A/JHD males with females from four different inbred strains produced recombinant populations with highly variable rates of affected offspring, ranging from none in C57BL/6J intercrosses, to a few mice with HD using 129S1/SvImJ intercrosses and C57BL/6J backcrosses, but nearly 8% of intercrosses and >17% of backcrosses from SJL/J related populations developed HD. Linkage analyses of these SJL/J derived recombinants identified three highly significant loci: a recessive locus mapping to distal chromosome 5 (LOD=4.88; named Emhd1 for eosinophilic myocarditis to heart disease-1); and two dominant variants mapping to chromosome 17, one (Emhd2; LOD=7.51) proximal to the major histocompatibility complex, and a second (Emhd3; LOD=6.89) that includes the major histocompatibility region. Haplotype analysis identified the specific crossovers that defined the Emhd1 (2.65Mb), Emhd2 (8.46Mb) and Emhd3 (14.59Mb) intervals. These results indicate the HD trait in this mutant mouse model of eosinophilic myocarditis is oligogenic with reduced penetrance, due to multiple segregating variants and possibly additional genetic or nongenetic factors. The A/JHD mouse model represents a unique and valuable tool to understand the interplay of causal factors that underlie the pathology of this newly discovered eosinophil-associated disease with cardiac complications.

genetics↗

bioRxiv2019

Highly efficient genome editing in primary bronchial epithelial cells establishes FOXJ1 as essential for ciliation in human airways

The structure and composition of the bronchial epithelium is altered in respiratory diseases such as COPD and asthma, in which goblet cell hyperplasia and reduced numbers of ciliated cells impair mucociliary clearance. We describe a robust genome editing pipeline to interrogate modulators of primary human bronchial epithelial cell (HBEC) differentiation and function. By employing plasmid- and virus-free delivery of CRISPR/Cas9 to human airway basal cells we achieve highly efficient gene inactivation without the need for positive selection. Genome edited cells are differentiated at air liquid interface (ALI) into a pseudo-stratified epithelium. We focus on profiling ciliation using imaging cytometry coupled to confocal microscopy and immunohistochemistry. To our knowledge, this is the first study to describe highly efficient genome editing of ALI cultured primary HBECs. As proof of concept, we establish that inactivation of the gene encoding the transcription factor FOXJ1 in primary human airway basal cells precludes ciliation in ALI differentiated bronchial epithelia.

molecular biology↗