Dataset Information

Transcriptomic analysis of pulmonary artery smooth muscle cells identifies new potential therapeutic targets for idiopathic pulmonary arterial hypertension.

ABSTRACT:

Background and purpose

Pulmonary arterial hypertension (PAH, type 1 pulmonary hypertension) has a 3-year survival of ~50% and is in need of new, effective therapies. In PAH, remodelling of the pulmonary artery (PA) increases pulmonary vascular resistance and can result in right heart dysfunction and failure. Genetic mutations can cause PAH but it can also be idiopathic (IPAH). Enhanced contractility and proliferation of PA smooth muscle cells (PASMCs) are key contributors to the pathophysiology of PAH, but the underlying mechanisms are not well understood.

Experimental approach

We utilized RNA-sequencing (RNA-seq) of IPAH and control patient-derived PASMCs as an unbiased approach to define differentially expressed (DE) genes that may identify new biology and potential therapeutic targets.

Key results

Analysis of DE genes for shared gene pathways revealed increases in genes involved in cell proliferation and mitosis and decreases in a variety of gene sets, including response to cytokine signalling. ADGRG6/GPR126, an adhesion G protein-coupled receptor (GPCR), was increased in IPAH-PASMCs compared to control-PASMCs. Increased expression of this GPCR in control-PASMCs decreased their proliferation; siRNA knockdown of ADGRG6/GPR126 in IPAH-PASMCs tended to increase proliferation.

Conclusion and implications

These data provide insights regarding the expression of current and experimental PAH drug targets, GPCRs and GPCR-related genes as potentially new therapeutic targets in PAH-PASMCs. Overall, the findings identify genes and pathways that may contribute to IPAH-PASMC function and suggest that ADGRG6/GPR126 is a novel therapeutic target for IPAH.

SUBMITTER: Gorr MW

PROVIDER: S-EPMC7348089 | biostudies-literature |

REPOSITORIES: biostudies-literature

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Project description:Contraction of human pulmonary artery smooth muscle cells (HPASMC) isolated from pulmonary arterial hypertensive (PAH) and normal (non-PAH) subject lungs was determined and measured with real-time electrical impedance. Treatment of HPASMC with vasoactive peptides, endothelin-1 (ET-1) and bradykinin (BK) but not angiotensin II, induced a temporal decrease in the electrical impedance profile mirroring constrictive morphological change of the cells which typically was more robust in PAH as opposed to non-PAH cells. Inhibition with LIMKi3 and a cofilin targeted motif mimicking cell permeable peptide (MMCPP) had no effect on ET-1 induced HPASMC contraction indicating a negligible role for these actin regulatory proteins. On the other hand, a MMCPP blocking the activity of caldesmon reduced ET-1 promoted contraction pointing to a regulatory role of this protein and its activation pathway in HPASMC contraction. Inhibition of this MEK/ERK/p90RSK pathway, which is an upstream regulator of caldesmon phosphorylation, reduced ET-1 induced cell contraction. While the regulation of ET-1 induced cell contraction was found to be similar in PAH and non-PAH cells, a key difference was the response to pharmacological inhibitors and to siRNA knockdown of Rho kinases (ROCK1/ROCK2). The PAH cells required much higher concentrations of inhibitors to abrogate ET-1 induced contractions and their contraction was not affected by siRNA against either ROCK1 or ROCK2. Lastly, blocking of L-type and T-type Ca2+ channels had no effect on ET-1 or BK induced contraction. However, inhibiting the activity of the sarcoplasmic reticulum Ca2+ ATPase blunted ET-1 and BK induced HPASMC contraction in both PAH and non-PAH derived HPASMC. In summary, our findings here together with previous communications illustrate similarities and differences in the regulation PAH and non-PAH smooth muscle cell contraction relating to calcium translocation, RhoA/ROCK signaling and the activity of caldesmon. These findings may provide useful tools in achieving the regulation of the vascular hypercontractility taking place in PAH.