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Genetic association and gene expression analysis of inflammatory genes in cystic fibrosis

University of British Columbia

Cystic fibrosis (CF) is characterized by a progressive decline in lung function due to airway obstruction, infection, and inflammation. CF patients are particularly susceptible to respiratory infection by a variety of pathogens, and the inflammatory response in CF is dysregulated and prolonged. This thesis identifies and characterizes BPI fold containing family A, member 1 (BPIFA1) and BPIFB1 as putative anti-inflammatory molecules in CF, and explores the CF inflammatory response to rhinovirus infection. BPIFA1 and BPIFB1 are proposed innate immune molecules expressed in the upper airways. We interrogated BPIFA1/BPIFB1 single-nucleotide polymorphisms in data from the North American genome-wide association study (GWAS) for lung disease severity in CF and discovered that the G allele of rs1078761 was associated with reduced lung function in CF patients. Microarray and qPCR gene expression analysis implicated rs1078761 G as being associated with reduced BPIFA1 and BPIFB1 gene expression, suggesting that decreased levels of these genes are detrimental in CF. Functional assays to characterize the role of BPIFA1 and BPIFB1 in CF indicated that these molecules do not have an anti-bacterial role against P. aeruginosa, but do have an immunomodulatory function in CF airway epithelial cells. To further investigate the mechanism of action of BPIFA1 and BPIFB1 during bacterial infection, gene expression was profiled using RNA-Seq in airway epithelial cells stimulated with P. aeruginosa and treated with recombinant BPIFA1 and BPIFB1. Viral infections are now recognized to play an important role in the short and long term health of CF patients. Rhinovirus is emerging as a lead viral pathogen although little is known about the inflammatory response triggered by rhinovirus in the CF lung. To investigate whether CF patients have a dysregulated response to rhinovirus infection, primary airway epithelial cells from CF and healthy control children were infected with rhinovirus and gene expression profiles were assessed by RNA-Seq. Although rhinovirus stimulation resulted significantly altered gene expression, the response to infection was not different in CF patients compared to healthy controls. However, CF cells had significantly higher rhinovirus levels than controls, indicating that CF patients may have a deficient antiviral response allowing for increased rhinovirus replication.

Text

2017-03-31

Attribution-NonCommercial-NoDerivatives 4.0 International

http://hdl.handle.net/2429/59277

Experimental Medicine

University of British Columbia

UBCV

http://creativecommons.org/licenses/by-nc-nd/4.0/