Enhancer of Zeste Homolog 2 Induces Pulmonary Artery Smooth Muscle Cell Proliferation

Abstract

IntroductionPulmonary Arterial Hypertension (PAH) is a progressively devastating disease characterized by excessive proliferation of the Pulmonary Arterial Smooth Muscle Cells (PASMCs). Studies suggest that PAH and cancers share an apoptosis-resistant state featuring excessive cell proliferation. The proliferation of cancer cells is mediated by increased expression of Enhancer of Zeste Homolog 2 (EZH2), a mammalian histone methyltransferase that contributes to the epigenetic silencing of target genes. However, the role of EZH2 in PAH has not been studied. In this study, it is hypothesized that EZH2 could play a role in the proliferation of PASMCs.MethodsIn the present study, the expression patterns of EZH2 were investigated in normal and hypertensive mouse PASMCs. The effects of EZH2 overexpression on the proliferation of human PASMCs were tested. PASMCs were transfected with EZH2 or GFP using nucleofector system. After transfection, the cells were incubated for 48 hours at 37°C. Proliferation and cell cycle analysis were performed using flow cytometry. Apoptosis of PASMCs was determined using annexin V staining and cell migration was tested by wound healing assay.ResultsEZH2 protein expression in mouse PASMCs were correlated with an increase in right ventricular systolic pressure and Right Ventricular Hypertrophy (RVH). The overexpression of EZH2 in human PASMCs enhances proliferation, migration, and decrease in the rate of apoptosis when compared to GFP-transfected cells. In the G2/M phase of the EZH2 transfected cells, there was a 3.5 fold increase in proliferation, while there was a significant decrease in the rate of apoptosis of PASMCs, when compared to control.ConclusionThese findings suggest that EZH2 plays a role in the migration and proliferation of PASMCs, which is a major hallmark in PAH. It also suggests that EZH2 could play a role in the development of PAH and can serve as a potential target for new therapies for PAH.

MicroRNA 16 modulates epithelial sodium channel in human alveolar epithelial cells

“…Equal amounts of RNA were reverse transcribed into cDNA using the iScript cDNA synthesis kit (Bio-Rad, Hercules, CA) and cDNA was amplified using qPCR performed on a Biorad CFX96 real-time PCR detection system as described earlier [16] . All primers were purchased from Integrated DNA Technologies (Coralville, IA) and were used at final concentrations of 100 nM.…”

Enhancer of zeste homolog-2 (EZH2) methyltransferase regulates transgelin/smooth muscle-22α expression in endothelial cells in response to interleukin-1β and transforming growth factor-β2

“…On the other hand, increased expression of EZH2 is often seen in highly proliferating cells [37]. EZH2 expression levels also influence the differentiation decisions in human bone marrow-derived mesenchymal stem cells [38].…”

Role of epigenetics in pulmonary hypertension

“…Aljubran et al (1) examined the role of the HMT, enhancer of zeste homolog 2 (EZH2), in PH. They found that increased levels of EZH2 in mice led to apoptotic resistance, as well as increased proliferation and migration of PASMCs.…”

“…This was possibly secondary to silencing of proapoptotic and antiproliferative genes. Human studies examining the effect of EZH2 in the development of PH, as well as examining the therapeutic benefit of EZH2 inhibition, should be conducted (1).…”