Abstracts

#29 Profiling Circular RNAs in Normal and Nitrofen-induced Hypoplastic Lung Development due to Congenital Diaphragmatic Hernia (CDH) 


Shana Kahnamoui, University of Manitoba; Naghmeh Khoshgoo, University of Manitoba; Thomas Mahood, University of Manitoba; Richard Keijzer, University of Manitoba


Introduction

Circular RNAs (circRNAs) have recently been identified as endogenous non-coding RNAs that are evolutionarily conserved in eukaryotic cells. Compared with linear RNAs, circRNAs are more stable, more abundant and specific. CircRNAs regulate gene expression at transcriptional and post-transcriptional levels by serving as microRNA sponges and interact with long-non-coding RNAs, mRNA, or proteins. However, the role of circRNAs in lung development is currently undefined. We aimed to identify circRNAs in normal lung development and nitrofen-induced hypoplastic lung development due to congenital diaphragmatic hernia (CDH).


Methods

We induced abnormal lung development and CDH by gavaging nitrofen to dams on embryonic day (E) 9. We collected control and nitrofen-induced hypoplastic lung tissues at E21 and isolated total RNA. We performed an Arraystar rat circRNAs Microarray, version 2 (Arraystar Inc., Rockville, MD, USA) for to globally profile the RNA samples. In-depth statistical data analysis was performed to identify differentially expressed circRNAs. Pathway analysis was inferred using KEGG and Ingenuity Pathway Analysis (Qiagen) to elucidate high-level circRNAs roles.


Results

The results of hierarchical clustering show distinct circRNAs expression profiling among the samples. In total 36 circRNAs were altered, including 15 up-regulated and 21 down-regulated circRNAs, in nitrofen-induced hypoplastic lungs compared to control lungs (FC>=2, p<=0.05). Of interest, mmu_circRNA_31436 (FC=9.8, p=0.02) and rno_circRNA_007475 (FC=12.3, p=0.04) were the most prominent up and down regulated, respectively. We are currently validating these “hits” using in situ hybridization and RT-qPCR.


Conclusion

We determined the circRNA profile and identified important differences between nitrofen-induced hypoplastic lungs and control lungs in the expression of these circRNAs. Future studies will focus on the specific roles of these circRNAs during normal and abnormal lung development.