Abstract 13799: A Systems Approach to Target Discovery Identifies the Novel Role of lncRNA-SPANXA2-OT1 in Macrophage Chemotaxis
Prabhash K Jha, Lucas Y Itto, Aatira Vijay, Adrien Lupieri, Sarvesh Chelvanambi, Yuto Nakamura, Miguel C Barbeiro, Thanh-Dat Le, Taku Kasai, Dakota Becker-Greene, Abhijeet Sonawane, Sasha A Singh, Elena Aikawa, Shizuka Uchida, Masanori Aikawa- Physiology (medical)
- Cardiology and Cardiovascular Medicine
Background: Coronary artery disease (CAD) remains the leading cause of mortality worldwide. Macrophages play a crucial role in recruiting immune cells and regulating the inflammatory milieu through the release of a diverse array of cytokines and chemokines in CAD. Long noncoding RNAs (lncRNAs) interact with DNA, RNA, miRNA, and proteins which makes them attractive therapeutic targets. We hypothesized that the lncRNA, SPANXA2-OT1 , regulates macrophage chemotaxis in CAD.
Methods and Results: Gene-expression meta-analysis and weighted gene co-expression network analysis (WGCNA) of human CAD datasets identified 26 lncRNA-mRNA co-expression modules (Fig A). Network prioritization of top co-expression modules identified the SPANXA2-OT1 as a potential key candidate. The conservation analysis revealed that SPANXA2-OT1 is conserved only in primates. We validated the candidate coding-noncoding RNA regulatory triad in primary macrophages derived from healthy human PBMCs (n= 3-10). Loss-of-function experiments using antisense oligonucleotide (ASO) against SPANXA2-OT1 demonstrated decreased monocyte chemotaxis signature (Figure B and D), as recorded by unbiased global proteomics and RNA expression (IL8, CCL19 and CCL23) data. The expression of S PANXA2-OT1 was stimulated by IL1β (Fig C) and RNA in situ hybridization demonstrated it to be highly expressed in cytoplasm (Fig E) of macrophages. Luciferase assay established that SPANXA2-OT1 binds to miR-338 through its miRNA response elements (Fig F). Gain-of-function ( miR-338 mimic) and loss-of-function ( SPANXA2-OT1 ASO) experiments revealed that SPANXA2-OT1 : miR-338 axis regulates the expression of monocyte chemotactic genes (e.g., IL-8 ) that may contribute to the pathophysiology of CAD (Fig G and H).
Conclusion: Our results indicate that the lncRNA SPANXA2-OT1 regulates chemokine signature in macrophages and may provide a molecular basis for the identification of novel therapeutic targets for CAD.