Sphingosine kinase 1 regulates the pulmonary vascular immune response

Aberrant proliferation of pulmonary arterial smooth muscle (PASMCs) cells are a defining characteristic of pulmonary arterial hypertension (PAH) and leads to increased vascular resistance, elevated pulmonary pressure, and right heart failure. The Sphingosine kinase 1 (SPHK1)/Sphingosine-1 phosphate/ Sphingosine-1 phosphate receptor 2 pathway promotes vascular remodeling and induces PAH. The aim of this study was to identify genes and cellular processes that are modulated by over-expression of SPHK1 in human PASMCs (hPASMCs). RNA was purified and submitted for RNA sequencing to identify differentially expressed genes. Using a corrected p-value threshold of <0.05, there were 294 genes significantly up-regulated while 179 were significantly down-regulated. Predicted effects of these differentially expressed genes was evaluated using the freeware tool Enrichr to assess general gene set over-representation (enrichment) and Ingenuity Pathway Analysis (IPA™) for upstream regulator predictions. We found a strong change in genes that regulated the cellular immune response. IL6, STAT1, and PARP9, were elevated in response to SPHK1 over-expression in hPASMCs. The gene set enrichment mapped to a few immune modulatory signaling networks, including IFNG. Furthermore, STAT1 protein was elevated in primary hPASMCs isolated from PAH patients. In conclusion, these data suggest a role of Sphk1 regulates pulmonary vascular immune response in PAH. Overall design: Determine change in hPASMC transcriptome after SPHK1 over-expression. Two groups- vector control and SPHK1 over-expression run in triplicate (6 samples total)