Exposure to both Diurnal and Multi-Day Heat Stress results in Dramatic Changes in Gene Expression in Endometrial Organoids

Samantha Gardner ¹; Jessica Edge¹; Elton Rosas de Vasconcelos²; Niamh Forde¹ 

¹ Discovery and Translational Sciences Department, Leeds Institute of Cardiovascular and Metabolic Medicine, School of Medicine, University of Leeds, Leeds, United Kingdom
 ² LeedsOmics, University of Leeds, Leeds, UK 


Abstract Text:

One of the most pressing issues facing the planet today is climate change. The importance of investigating the impact a warming environment will have on reproduction cannot be underestimated. These effects are multifaceted with potentially direct effects on human and animal germ cell production, embryo viability and pregnancy success. Furthermore, this may lead to failure of the offspring to thrive and reproduce, with knock-on effects for livestock production for food as well as human health. The highly dynamic endometrial tissue sits at the interface between the maternal and foetal systems and may have a key role in mediating a response to heat stress (HS). We tested the hypothesis that Porcine endometrial organoids would respond to heat stress in a temporal manner with respect to a short term versus a long-term exposure. Endometrial tissue was isolated from Porcine reproductive tracts at necropsy on Day 7 of pregnancy from a timed insemination. Endometrial organoids were cultured in cultrex (extracellular matrix) using a standard 38.5°C temperature for Porcine tissue. On Day 7 of culture, organoids were exposed to a HS (40°C) to simulate a diurnal (18hr) or multiday exposure (72hr) or maintained at control (38.5°C). Following RNA extraction, sequencing was carried out using the Novoseq X Plus series platform and differential expression analysis utilising DeSeq2 (padj < 0.05).Overall principal component analysis of the 28101 transcripts detected in the endometrial organoids showed all the control and HS samples clustered together. Comparison of the diurnal (18hr) exposure to control we found 1208 differentially expressed genes (DEGs, padj < 0.05, Fold change >2), with 731 showing increased expression and 477 decreased expression with HS. Further analysis of the multi-day (72hr) HS demonstrated 2824 DEGs with 1527 increased and 1297 decreased with heat exposure when compared to control. There are 643 transcripts that are consistently changed following either HS exposure length, and over representation analysis (ORA) shows enrichment of GO terms including organelle fission and cell division processes. In addition, we show that 292 DEGs show temporal change in control organoids between 18 and 72 hrs. But this dramatically increased to 1745 DEGs in those exposed to HS. Interestingly, ORA highlights changes in genes associated with placental development. These important data demonstrate that endometrial organoids exhibit significant alterations in the gene expression profile on exposure to a HS and these gene expression changes are exacerbated with length of exposure. Furthermore, this highlights the importance of detailed investigation to elucidate crucial signaling mechanisms in the endometrial response to HS.