Transcriptomic analysis identifies Toll-like and Nod-like pathways and necroptosis in pulmonary arterial hypertension

Inflammation and immunity play a causal role in the pathogenesis of pulmonary vascular remodelling and pulmonary arterial hypertension (PAH). However, the pathways and mechanisms by which inflammation and immunity contribute to pulmonary vascular remodelling remain unknown. RNA sequencing was used to analyse the transcriptome in control and rats injected with monocrotaline (MCT) for various weeks. 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) and Nod-like receptor (NLR) pathways and identified NF-κB-mediated inflammatory and immune profiling in MCT-induced PAH. Pathway-based data integration and visualization showed the dysregulated TLR and NLR pathways, including increased expression of TLR2 and NLRP3, and their downstream molecules. Further analysis revealed that the activation of TLR and NLR pathways was associated with up-regulation of damage-associated molecular patterns (DAMPs) and RIPK3-mediated necroptosis was involved in the generation of DAMPs in MCT-induced PAH. Collectively, we identify RIPK3-mediated necroptosis and its triggered TLR and NLR pathways in the progression of pulmonary vascular remodelling, thus providing novel insights into the mechanisms underlying inflammation and immunity in the pathogenesis of PAH.