PIK3R1 and pulmonary arterial hypertension: The hub genes HSP90AA1, CDC5L, LRRK2, PIK3R1, MAPK6, HIF1A, HNRNPA1, MET, and IQGAP1, and TFs RBBP9, GATA3, and TAF1 were significantly higher in PAH rat lung tissue after 2 weeks of monocrotaline injection.