Transcriptomic Analysis Identifies Necroptosis and Toll-Like Receptor Pathways in Pulmonary Arterial Hypertension

Background: Inflammation and immunity play a causal role in the pathogenesis of pulmonary arterial hypertension (PAH). However, the pathways and mechanisms by which inflammation and immunity are triggered remain unknown. Methods: High-throughput RNA sequencing was used to analyze the transcriptome change in control and rats injected with monocrotaline (MCT) for 1, 2, 3 and 4 weeks. The obtained animal results were further analyzed in two independent microarray datasets derived from patients with PAH. Findings: Using the transcriptional profiling of MCT-induced PAH coupled with bioinformatics analysis, we clustered the differentially expressed genes (DEGs) and chose the increased expression patterns associated with inflammatory and immune response, we found the enrichment of toll-like receptor (TLR) pathways and identified NF-κB-mediated inflammatory and immune profiling. Pathway-based data integration and visualization showed the dysregulated TLR pathways. Further analysis revealed that the activation of TLR pathways was associated with upregulation of damage-associated molecular patterns (DAMPs) and RIPK3-mediated necroptosis was involved in the generation of DAMPs in MCT-induced PAH. Reversal of necroptosis by modern drug therapy was in accordance with attenuated expression of DAMPs, impaired activation of TLR pathways and inflammatory and immune profiling in patients with PAH. Moreover, these clinical results were validated by using currently largest clinical PAH dataset. Interpretation: We identify RIPK3-mediated necroptosis and its triggered TLR pathways in the pathogenesis of PAH, thus, providing insights into the mechanisms underlying inflammation and immunity in PAH. Funding Statement: This work was supported by grants from the National Natural Science Foundation of China (Grant No. 81873537 and 81570446). Declaration of Interests: The authors declare no conflict of interest. Ethics Approval Statement: All procedures have been conducted in accordance with the ARRIVE guidelines and were approved by the Laboratory Animal Welfare and Ethics Committee of Fujian Medical University (Approval No. 2017–070, Fuzhou, China).