Regulation of circular RNAs act as ceRNA in a hypoxic pulmonary hypertension rat model.

To explore potential critical genes and identify circular RNAs (circRNAs) that act as the competitive endogenous RNA (ceRNA) in a hypoxic pulmonary hypertension (HPH) rat model. Constructed rat model, and a bioinformatics method was used to analyse differentially expressed (DE) genes and construct a circRNA-miRNA-mRNA ceRNA regulatory network. Then, qRT-PCR was used to verify. The significant DEcircRNAs/DEmiRNAs/DEmRNAs was showed, and a ceRNA network with 8 DEcircRNAs, 9 DEmiRNAs and 46 DEmRNAs were constructed. The functional enrichment suggested the inflammatory response, NF-κB signalling, MAPK cascade and Toll-like receptor were associated with HPH. Further assessment confirmed that circ_002723, circ_008021, circ_016925 and circ_020581 could have a potential ceRNA mechanism by sponging miR-23a or miR-21 to control downstream target gene and be involved in the pathophysiology of HPH. The qRT-PCR validation results were consistent with the RNA-Seq results. This study revealed potentially important genes, pathways and ceRNA regulatory networks in HPH.

PDGF mediates pulmonary arterial smooth muscle cell proliferation and migration by regulating NFATc2.

The reconstruction of pulmonary vascular structure caused by the proliferation and migration of pulmonary arterial smooth muscle cells (PASMCs) is the central link in the formation of pulmonary arterial hypertension (PAH). Platelet­derived growth factor (PDGF) can regulate the proliferation and migration of PASMCs. At the same time, nuclear factor of activated T cells (NFATs) plays an important role in the development of PAH. To the best of our knowledge, there are no reports yet regarding whether PDGF regulates NFATc2 to increase the proliferation of PASMCs. The present study aimed to investigate whether PDGF affects the proliferation and migration of PASMCs by regulating NFAT, and to study the pathogenesis of PAH. PASMCs were treated with recombinant PDGF; Cell Counting Kit­8 and clone formation experiments showed that PDGF enhanced the cell viability and proliferation of PASMCs. Cell cycle distribution and molecular markers related to cell proliferation (cyclin D1, CDK4 and Proliferating Cell Nuclear Antigen) were detected by flow cytometry, and the results indicated that PDGF promoted the division of PAMSCs. The scratch migration and Transwell migration assays showed that the migratory ability of PASMCs was enhanced following PDGF treatment. Changes in NFATs (NFATc1­5) after PDGF treatment were evaluated by reverse transcription­quantitative PCR and western blotting; NFATc2 showed the most significant results. Finally, PDGF­treated cells were treated with an NFAT pathway inhibitor, cyclosporin A, or a small interfering RNA targeting NFATc2, and changes in cell proliferation and migration were evaluated to assess the role of NFATc2 in PDGF­induced cell proliferation and migration. In conclusion, PDGF may regulate PASMC proliferation and migration by regulating the expression of NFAT, further leading to the occurrence of PAH. It is proposed that NFATc2 could be used as a potential target for PAH treatment.

Autophagy in pulmonary hypertension: Emerging roles and therapeutic implications.

Autophagy is an important mechanism for cellular self-digestion and basal homeostasis. This gene- and modulator-regulated pathway is conserved in cells. Recently, several studies have shown that autophagic dysfunction is associated with pulmonary hypertension (PH). However, the relationship between autophagy and PH remains controversial. In this review, we mainly introduce the effects of autophagy-related genes and some regulatory molecules on PH and the relationship between autophagy and PH under the conditions of hypoxia, monocrotaline injection, thromboembolic stress, oxidative stress, and other drugs and toxins. The effects of other autophagy-related drugs, such as chloroquine, 3-methyladenine, rapamycin, and other potential therapeutic drugs and targets, in PH are also described.

Serum cardiac troponin elevation predicts mortality in patients with pulmonary hypertension: A meta-analysis of eight cohort studies.

OBJECTIVE: To determine the association of serum cardiac troponin (cTn) with the mortality of pulmonary hypertension (PH) patients via a meta-analysis. DATE SOURCE: We searched PubMed and EMBASE from inception to October 25, 2017. STUDY SELECTION: The reference lists of the retrieved articles were also consulted. The Q test and I2 test were used for to assess heterogeneity. The relationship between cTn elevation and mortality was analysed. Studies were stratified according to type of troponin (cTnT vs cTnI), region (Europe vs America) and follow-up length (≤3 years vs >3 years). RESULTS: Eight studies with 739 patients were included in the meta-analysis. Cardiac troponin elevation ranged from 14.3% to 94.5%. Overall, 48.8% (39/80) of patients with elevated cTn died compared to 18.6% (45/242) of patients with normal cTn levels. These findings showed cTn elevation was significantly related to an increased mortality risk in PH patients [hazard ratio (HR) = 3.05, 95% confidence interval (95% CI) = 2.16-4.32, I2  = 24.9%]. cTnI was better at predicting mortality than cTnT (HR = 3.37, 95%CI = 2.05-5.55 vs HR = 2.80, 95%CI = 1.97-3.98, respectively). American populations had increased mortality compared to European populations (HR = 4.23, 95%CI = 2.29-7.80 vs HR = 2.70, 95% CI = 1.95-3.74, respectively). This finding was independent of the follow-up length of the studies (≤3 years: HR = 2.36, 95%CI = 1.65-3.38; >3 years: HR = 4.55, 95%CI = 2.80-7.39). CONCLUSIONS: Although different studies detected the expression cTnT or cTnI by various methods, the mortality in the cTn-positive group was higher than that in the cTn-negative group. Serum cTn elevation emerged as an independent predictor of increased risk of mortality in PH patients.