Influence of sex and disease severity on gene expression profiles in individuals with idiopathic pulmonary fibrosis.

Epidemiological studies suggest sex-specific trends in the prevalence and mortality of idiopathic pulmonary fibrosis (IPF) and chronic obstructive pulmonary disease (COPD) that are distinct for each disease. While the expression of numerous immune and extracellular matrix (ECM) genes in the lung have been well characterized in these diseases, associations elucidating their sex-specific expression patterns by disease type and severity, and the evaluation of hormone-related genes, have not been well studied. Here we performed targeted transcriptional profiling of 48 genes was performed on lung tissue samples from males and females with mild or medium severity IPF or COPD. The genes assessed included those involved in inflammation, ECM remodeling and hormonal processes. Data for 36 lung tissue samples were obtained that were stratified by disease and sex. Expression levels revealed a subset of genes which show differential expression among sexes, disease type, and disease severity. The most significant observations were the increased expression primarily of ECM genes in medium severity IPF (CATHK, COL1A1, COL3, MMP1, MMP7, IL-1RN) compared to mild IPF and COPD. Two genes, CH3L1 and MMP7 showed a tendency of interaction between sex and disease in IPF severity. Surprisingly, there were no significant differences in any of the sex genes measured between the IPF groups; however, ESR1 and AR expression levels were higher and lower, respectively, compared to COPD samples. Overall, this work highlights two genes, CH3L1 and MMP7, that may contribute to gender trends observed for IPF and COPD and are potential targets for future research.