Abstract Body (Do not enter title and authors here): Introduction: Pulmonary arterial hypertension (PAH) is a progressive and fatal disease characterized by pulmonary artery (PA) remodeling. Extensive proliferation of PA smooth muscle cells (PASMCs) is perhaps the most important feature of PAH accounting for vascular remodeling for which current treatments have limited efficacy.
Methods and Results: To discover novel actionable targets involved in vascular remodeling, we performed a comparative RNA-sequencing analysis between control and PAH-PASMCs, and next enriched our experiment with two publicly available datasets conducted on comparable cell lines. After merging the three datasets, 136 genes were found to overlap, of which 126 and 10 were up- and down-regulated in PAH-PASMCs, respectively. A connectivity map analysis using SigCom Library of Integrated Network-based Cellular Signatures was performed on the commonly upregulated genes and identified an aurora kinase B (AURKB) inhibitor as the top reverser drug of PAH-PASMCs gene signature. In this regard, aurora kinase B (AURKB), known to play a critical role in the onset and progression of mitosis, was present among the overlapping upregulated genes in PAH-PASMCs. Further experiments revealed that FOXM1 positively regulates AURKB expression. Pharmacological (Barasertib) and molecular (siRNA) inhibition of AURKB reduced PAH-PASMC proliferation (EDU incorporation, Ki67 labeling & WB PLK1), survival (TUNEL assay, & WB Survivin) and was associated with mitotic defects. Acquisition of a senescence-like phenotype was observed in PAH-PASMCs that escaped apoptosis following AURKB inhibition (SA-βGal, p21, p53, SASP…). Barasertib treatment significantly improved pulmonary vascular remodeling and hemodynamics in MCT and Su/Hx rats with established PAH (RHC & EVG) and resulted in a marked increase in p21 in small PAs. Similar effects were also observed in human precision-cut lung slices isolated from PAH patients. Finally, the combination of Barasertib with the p21 attenuator UC2288 was more effective in reducing vascular remodeling in Su/Hx rats than either drug alone (EVG, RHC, echocardiography).
Conclusion: Our research identified AURKB as a novel therapeutic target and suggests that combining anti-remodeling drugs with senotherapeutics may be more effective in counteracting vascular remodeling in PAH.