Abstract
AimTo investigate the role of bone morphogenetic protein 2 (BMP-2) in regulation of phosphatase and tensin homologue deleted on chromosome ten (PTEN) and apoptosis of pulmonary artery smooth muscle cells (PASMCs) under hypoxia.MethodsNormal human PASMCs were cultured in growth medium (GM) and treated with BMP-2 from 5–80 ng/ml under hypoxia (5% CO2+94% N2+1% O2) for 72 hours. Gene expression of PTEN, AKT-1 and AKT-2 were determined by quantitative RT-PCR (QRT-PCR). Protein expression levels of PTEN, AKT and phosph-AKT (pAKT) were determined. Apoptosis of PASMCs were determined by measuring activities of caspases-3, -8 and -9. siRNA-smad-4, bpV(HOpic) (PTEN inhibitor) and GW9662 (PPARγ antagonist) were used to determine the signalling pathways.ResultsProliferation of PASMCs showed dose dependence of BMP-2, the lowest proliferation rate was achieved at 60 ng/ml concentration under hypoxia (82.2±2.8%). BMP-2 increased PTEN gene expression level, while AKT-1 and AKT-2 did not change. Consistently, the PTEN protein expression also showed dose dependence of BMP-2. AKT activity significantly reduced in BMP-2 treated PASMCs. Increased activities of caspase-3, -8 and -9 of PASMCs were found after cultured with BMP-2. PTEN expression remained unchanged when Smad-4 expression was inhibited by siRNA-Smad-4. bpV(HOpic) and GW9662 (PPARγ inhibitor) inhibited PTEN protein expression and recovered PASMCs proliferation rate.ConclusionBMP-2 increased PTEN expression under hypoxia in a dose dependent pattern. BMP-2 reduced AKT activity and increased caspase activity of PASMCs under hypoxia. The increased PTEN expression may be mediated through PPARγ signalling pathway, instead of BMP/Smad signalling pathway.
Highlights
Hypoxic pulmonary hypertension, one of the most common pulmonary arterial hypertension, is characterized by increased proliferation and reduced apoptosis of smooth muscle cells [1]
The proliferative rate of pulmonary artery smooth muscle cells (PASMCs) showed dose dependence of Bone morphogenetic protein 2 (BMP-2) when PASMCs was cultured under hypoxia (Figure 1A&B)
The number of PASMCs treated with 5 ng/ml BMP-2 was reduced to 90.861% of non-treated PASMCs, while they were 92.961.8% with 10 ng/ml, 88.461.2% with 20 ng/ml, 84.162.8% with 40 ng/ml, 82.262.8% with 60 ng/ml, 86.661% with 80 ng/ml
Summary
One of the most common pulmonary arterial hypertension, is characterized by increased proliferation and reduced apoptosis of smooth muscle cells [1]. It contributes to increased pulmonary vascular resistance and increased pulmonary artery pressure. Bone morphogenetic protein 2 (BMP-2), which belongs to the transforming growth factor beta super-family, is a negative regulator of PASMC growth [3]. It is a potent inhibitor of vascular SMCs proliferation both in vitro and in vivo [3]. Hansmann et al, [5] shows that anti-proliferative effects of BMP-2/BMP-RII signaling in primary PASMCs can be attributed to activation of PPARc and its putative transcription target apoE
Sign-in/Register to view highlights & summary Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
