Introduction

Sex differences in asthma are well described, although the cause remains unknown. Male children experience increased rates and worse health outcomes than female children, with this pattern swapping after puberty. Hallmark features of inflammation, fibrosis and cell death promote asthma symptoms. ZFX and ZFY are transcription factors on the X and Y chromosome, respectively. It is unknown how ZFX and ZFY regulate the features of asthma; an imbalanced function may contribute to sex differences. We aimed to characterise the function of ZFX and ZFY in the context of inflammation, fibrosis and cell death.

Method

Knockout (KO) cell lines for ZFX and ZFY were generated. ELISA measured CXCL8 and IL6 cytokine production after 24hr TNF? stimulation. Cell death was measured post 24hr cigarette smoke exposure (CSE). Fibrotic processes were explored by analysing cell attachment, proliferation and wound healing. RNA-sequencing (RNA-seq) examined pathways regulated by ZFX and ZFY.

Results

ZFX KOs produced increased levels of IL6, yet CXCL8 was decreased compared to wildtype cells (p<0.05). RNA-seq revealed altered activation of CXCL8-relevant signalling proteins in ZFX KOs. ZFX KOs had increased cell attachment, decreased proliferation and faster wound healing (p<0.05). ZFY KOs indicated increased survival to CSE and a slower rate of wound healing (p<0.05). RNA-seq highlighted a breakdown of mitotic structures leading to slower wound closure.

Conclusion

This study uncovers novel functional differences between ZFX and ZFY. These differences are distinct and affect pathological features of asthma. As such, the imbalanced functions of ZFX and ZFY may contribute to sex differences in asthma incidence and severity.