Abstract
Asthma affects boys more than girls, but gender-switch occurs after puberty and asthma is more common in
women than men. This research proposal investigates the effect of sex and sex hormones on asthma severity.
The long-term goal of our studies is to identify sex related differences in genetic risks and biological pathways of
severe asthma. Our analyses of well characterized asthma cohorts and large databases reveal that severe
asthma exhibits a bimodal peak in young boys and middle age women [3], which pointes to sex hormones in
mechanisms of asthma severity. Preliminary data of sex hormone levels from women enrolled in SARP 1-3
(2001-2018) showed that FEV1 (%) correlated negatively with estradiol, but positively with progesterone.
Additionally, the adrenal androgen dehydro-epiandrosterone sulfate (DHEA-S) correlated positively with FEV1
(%) in women and men, but testosterone levels correlated with FEV1 (%) in men but not in women. Our data also
suggest that sex hormones modulate airway inflammation through their effect on sex steroids receptors (SSRs).
Gene expression data from bronchial epithelial cells obtained by bronchoscopy from 128 SARP 3 participants
with asthma revealed significant correlation between estrogen receptors 1 and 2 (ESR1 and ESR2) gene
expression and inflammatory cytokine receptors (IL6R, IL4R, IL5RA, and IL13RA1) gene expression. Our
preliminary analyses of SARP1-2 BEC microarray data (n= 72 women, 32 men) showed sex-specific differential-
targeting of groups of interacting genes representing particular biological functions (mitochondrial function in
women and interferon signaling in men). These data suggest that sex and sex hormones play an important role
in the clinical manifestations of asthma genetic risk variants. Based on these cumulative findings, we hypothesize
that sex and sex hormones influence immune system activation and airway inflammation to drive asthma
phenotypes and progression differentially in males and females across the lifespan. In aim 1 we evaluate how
sex hormone serum concentrations and SSRs expression in blood, upper, and lower airway cells determine T2
inflammation and asthma severity in men and women. In aim 2 we identify the sex-specific genetic effects of loci
across the genome on asthma risk and severity resulting from DNA variant interactions with hormone and nuclear
receptor expression. In aim 3, we will assess whether sexual dimorphism of asthma is related to a higher order
of gene interactions and variation in sex-specific configurations in gene regulatory networks. The proposed
studies have the potential to define key hormonal and genomic drivers of asthma risk and severity over the
lifespan in men and women and address a large knowledge gap of how sex and sex hormones modify asthma
risk and severity. Future studies will aim, using this data, to identify personalized, hormone-based risk
stratification and treatment approaches in men and women, irrespective of background ancestry.