NLRC3 inhibits MCT-induced pulmonary hypertension in rats via attenuating PI3K activation.

Phosphoinositide 3-kinase (PI3K) activation plays a critical role in the pulmonary vascular remodeling of pulmonary hypertension (PH). The nucleotide-oligomerization domain (NOD)-like receptor subfamily C3 (NLRC3) inhibits proliferation and inflammation via PI3K signaling in cancer. We previously showed NLRC3 was significantly reduced in PH patients, but the mechanism of function remains unclear. This study aimed to determine the potential role of NLRC3 in PH. We found that NLRC3 was downregulated in the pulmonary arteries of PH animal models and platelet-derived growth factor-BB (PDGF-BB) stimulated pulmonary arterial smooth muscle cells (PASMCs). NLRC3 pretreatment reduced right ventricular systolic pressure, attenuated pulmonary vascular remodeling and RVHI, and ameliorated proliferation, migration, and inflammation. Monocrotaline (MCT)- and PDGF-BB-mediated PI3K activation were suppressed by NLRC3 pretreatment. 740Y-P decreased the effect of NLRC3. Collectively, NLRC3 protected against MCT-induced rat PH and PDGF-BB-induced PASMC proliferation, migration, and inflammation through a mechanism involving PI3K inhibition. NLRC3 may have a therapeutic effect on PH and provide a promising therapeutic strategy for PH.

NLRC3: A Novel Noninvasive Biomarker for Pulmonary Hypertension Diagnosis.

The nucleotide-oligomerization domain (NOD)-like receptor subfamily C3 (NLRC3) is a newly discovered and incompletely characterized member of the NLR family which negatively regulates inflammatory responses. Inflammation is considered a critical pathogenesis in pulmonary hypertension (PH). This is the first study to hypothesize that NLRC3 is closely correlated with PH. Total of 43 PH patients who were diagnosed by right heart catheterization (RHC) and 20 age-matched healthy control subjects were included. Echocardiographic variables and blood biochemical parameters were tested. Results of World Health Organization functional class (WHOFC), Borg dyspnea score and 6-minute walk tests (6MWT) were recorded. Mean pulmonary arterial pressure (mPAP) and pulmonary vascular resistance (PVR) were measured from RHC. Serum NLRC3 concentrations were detected by ELISA. ROC curve analysis was used to evaluate the diagnostic value of NLRC3 concentrations in PH. We found that serum NLRC3 concentration was significantly decreased in PH compared to the healthy control group. Serum NLRC3 concentration correlated negatively with mPAP and PVR. In addition, a negative correlation between serum NLRC3 concentration and WHOFC were detected. We proposed a cut-off value of 2.897ng/mL for serum NLRC3 concentration which was able to predict PH with 88% sensitivity and 85% specificity. In conclusion, NLRC3 concentrations in PH were significantly decreased, suggesting that NLRC3 may potentially be a diagnosis index and represent a prognostic factor for PH patients.