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Pulmonary hypertension (PH) is a life-threatening disease characterized by pulmonary vascular remodeling, in which hyperproliferation of pulmonary artery smooth muscle cells (PASMCs) plays an important role. The cysteine 674 (C674) in the sarcoplasmic/endoplasmic reticulum Ca2+ ATPase 2 (SERCA2) is the critical redox regulatory cysteine to regulate SERCA2 activity. Heterozygous SERCA2 C674S knock-in mice (SKI), where one copy of C674 was substituted by serine to represent partial C674 oxidative inactivation, developed significant pulmonary vascular remodeling resembling human PH, and their right ventricular systolic pressure modestly increased with age. In PASMCs, substitution of C674 activated inositol requiring enzyme 1 alpha (IRE1α) and spliced X-box binding protein 1 (XBP1s) pathway, accelerated cell cycle and cell proliferation, which reversed by IRE1α/XBP1s pathway inhibitor 4μ8C. In addition, suppressing the IRE1α/XBP1s pathway prevented pulmonary vascular remodeling caused by substitution of C674. Similar to SERCA2a, SERCA2b is also important to restrict the proliferation of PASMCs. Our study articulates the causal effect of C674 oxidative inactivation on the development of pulmonary vascular remodeling and PH, emphasizing the importance of C674 in restricting PASMC proliferation to maintain pulmonary vascular homeostasis. Moreover, the IRE1α/XBP1s pathway and SERCA2 might be potential targets for PH therapy.
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@#To observe the effect of miR-34a on the proliferation of pulmonary artery smooth muscle cells in rats induced by hypoxia and explore its possible mechanism.【Methods】Rat pulmonary artery smooth muscle cells were primarily isolated from pulmonary arteriole and cultured. After 3% O2 treatment，the expression of miR- 34a and Notch1 mRNA in rat PASMC were detected by real time PCR. The cell proliferation was detected by EDU after over-expression and inhibition of miR-34a and silencing Notch1 by cell transfection under hypoxia，and the expression of PCNA was detected by real time PCR and western blot method.【Results】We successfully isolated and cultured rat PASMC. And after 3% O2 treatment，the expression of miR-34a in rat PASMC was significantly decreased after 48 h compared with 24 h（P < 0.05）. However，the expression of Notch1 mRNA increased significantly after 48 h compared with 24 h（P < 0.05）. In addition， over-expression of miR-34a and silencing Notch1 significantly inhibited hypoxia-induced cell proliferation ，while inhibition of miR-34a significantly promoted the PASMC proliferation（P < 0.05）.【Conclusion】miR-34a participates in the proliferation of PASMC induced by hypoxia，and it may be through up-regulation of Notch1 to induce cell proliferation.
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In acute hypoxia, pulmonary vascular will contract and divert blood to better ventilated area to optimize ventilation/perfusion matching, which is known as hypoxic pulmonary vasoconstriction (HPV). In chronic hypoxia, irreversible pulmonary vascular remodeling can be induced, characterized by pulmonary artery middle smooth muscle cells and the outer fiber cell hyperplasia in luminal stenosis and pulmonary artery hypertension (PAH) eventually. Furthermore, PAH can cause increased ventricular afterload, and right heart failure in severe cases. Pulmonary artery smooth muscle cell (PASMC) elevated Ca2+ concentration is one of the most important factors of its contractions, proliferation and migration. Recent studies on Ca2+ promoting in HPV were summarized in order to provide evidence for clinical prevention of hypoxia and therapeutic PAH.
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Objective To explore the effect of beraprost sodium (BPS) on hypoxia-induced pulmonary artery hypertension (HPH) in rats and the expression of oxygen-sensitive Kv channels in pulmonary artery smooth muscle (PASM).Methods The HPH model of rats was established by exposing rats to low-pressure and low-oxygen cabin which was auto-modulated for 8h every day.Rats in the BPS group were given an intragastric administration of BPS [300 μg/(kg · d)],while those in the control group and HPH group were given an intragastric administration of 3 ml/kg of 0.9％ saline.After 4 weeks,the mean pulmonary artery pressure (mPAP) was measured and right heart ventricle hypertrophy index (RVHI) was calculated;pulmonary artery remodeling was evaluated by HE staining;the expressions of Kv 1.2,Kv 1.5 and Kv2.1 in the pulmonary artery were detected by Real-time PCR and Western blot.Results The HPH model was successfully established in rats exposed to chronic hypoxia for 4 weeks.Compared with those in HPH group,mPAP,RVHI and pulmonary artery remodeling were decreased in BPS group [mPAP:(13.48±2.18)mmHg vs.(23.87±2.23)mmHg vs.(17.09±1.20)mmHg;RVHI:0.28±0.02 vs.0.46±0.03 vs.0.36±0.04;％ area of medial smooth muscle:35.72±6.58 vs.68.52±5.64 vs.46.58±8.43;P＜0.05],and the mRNA and protein expressions of Kv 1.2,Kv 1.5 and Kv 2.1 were increased (relative protein expression level:Kv1.2,0.78±0.10 vs.0.15±0.03 vs.0.57±0.13;Kv1.5,0.61±0.10 vs.0.31±0.05 vs.0.59±0.13;Kv2.1,0.29±0.05 vs.0.10±0.02 vs.0.28±0.07;P＜0.05).Conclusion BPS can improve pulmonary arterial hypertension induced by hypoxia,and upregulate the decreased mRNA and protein expressions of Kv 1.2,Kv 1.5 and Kv 2.1 in pulmonary artery.
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Objectives To explore the effect of mibefradil, a kind of novel calcium channel antagonists, on proliferation of human pulmonary artery smooth muscle cells (HPASMCs) induced by platelet-derived growth factor (PDGF). MethodsHPASMCs were culturedin vitro, and randomly divided into control group, PDGF group, Mib group, and PDGF+Mib group. The PDGF group was stimulated by 25 ng/ml of PDGF. Mib group was intervented by 10 μmol/L of Mib. PDGF+Mib group was treated by PDGF and Mib. The reproduction rate in 48 hours and 72 hours were detected by MMT. Cell cycle was detected by lfow cytometry. The expression of proliferating cell nuclear antigen (PCNA) was observed by immunolfuorescence staining (IFS).ResultsThere were statistical differences among four groups in both 48 hours and 72 hours (P all??0.05). There were statistically differences of G0/G1 phase and S phase among four groups (P?
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[Abstract ] Objective Chronic obstructive pulmonary disease (COPD) is closely related to pulmonary hypertension .This study was to investigate the correlation of the expression of high mobility group protein B 1 ( HMGB1) with its synthesis and secretion of interferon-γ( IFN-γ) in the distal pulmonary arterial smooth muscle cells ( PASMCs ) of COPD rats and its clinical significance . Methods We established COPD models in rats , primarily cultured and identified PASMCs , and detected the synthesis and secretion of cytokine in the PASMCs induced by cigarette smoke extract (CSE) and/or lipopolysaccharide (LPS).The PASMCs in the control, CSE, LPS, and CSE+LPS groups were cultured with anti-HMGB1 antibodies at 0.2 mL 1∶1000.At 12, 24, 48 and 72 hours of inter-vention, the expression of HMGB1 in the PASMCs was detected by Western blot and the concentrations of HMGB 1 and IFN-γin the cell culture supernatant were measured by ELISA , followed by a correlation analysis . Results Light microscopy manifested a peak -valley growth pattern or fusiform shape of the cells , which were identified as PASMCs by α-actin immunohistochemistry and immuno-fluorescence .Western blot and ELISA showed statistically significant differences in the expression of HMGB 1 and concentrations of cell supernatant HMGB1 and IFN-γat 12 hours between any two of the four groups (P0.05). Conclusion The expression level of HMGB1 was positively correla-ted with the synthesis and secretion of IFN-γin the distal PASMCs of the COPD model rats , and anti-HMGB1 antibodies provide a new in-tervention target for the clinical treatment of COPD and inhibition of its systemic inflammatory response .
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Pulmonary artery hypertension (PAH)is a common clinical syndrome.The over-proliferation of pulmonary arterial smooth muscle cells (PASMCs)is a hallmark of pulmonary vascular remodeling which is a critical and fundamental pathogenesis in the development of a variety of pulmonary artery hypertension.Here,we review the advances in studies on signaling transduction pathways mediating the proliferation of PASMCs and also introduce the existing approaches in inhibiting their proliferation and relevant research advances.
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Objective To explore the effect of nuclear transcription factor kappaB(NF-κB) pathway on proliferation of rat pulmonary artery smooth muscle cells (PASMC) induced by platelet-derived growth factor (PDGF).Methods PASMC isolated from rats and cultured in vitro were divided into 3 groups according to the randomization principle:control group(cultured by M199),PDGF treatment group(cultured by M199 and stimulated by PDGF),PDGF + parthenolide treatment group (cultured by M199 and stimulated by PDGF,and intervented by the NF-κB inhibitors parthenolide).MTT colorimetric assay and flow cytometry were performed to detect cell proliferation and cell cycle distribution.Immunohistochemistry was performed to detect the expressions of NF-κB and COX-2 protein.Fluorescence quantitative RT-PCR was performed to detect NF-κB and COX-2 mRNA expressions.One-way ANOVA was used for statistical analysis,multiple comparisons were analyzed by LSD.Results Compared with the control group,MTT value of PASMC was increased significantly when induced by PDGF at each time points(all P ＜ 0.05).MTT value decreased dramatically after the intervention of NF-κB inhibitor parthenolide(P ＜0.05).Data from flow cytometry detection showed that cell proportion of S phase and G2 + M phase increased significantly in PDGF treatment group,which had statistical difference compared with control group (all P ＜ 0.05).Compared with PDGF induced group,after the intervention of parthenolide,cell proportion of S phase and G2 + M phase ratio decreased dramatically (P ＜ 0.05).The expressions of NF-κB and COX-2 protein and mRNA were promoted in the PDGF induced group compared with the control group (all P ＜ 0.05).Compared with PDGF induced group,after the intervention of parthenolide,the expressions of NF-κB and COX-2 protein and mRNA decreased dramatically(all P ＜ 0.05).Conclusions PDGF can induce proliferation of PASMC,promote cell cycle process and enhance the expressions of NF-κB and COX-2 protein and mRNA.NF-κB pathway involves in the proliferation of PASMC induced by PDGF.
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Objective To investigate the characteristics of different electrophysiology of Ca2+-activated Cl-channels (ClCa) in pulmonary arterial smooth muscle cells (PASMCs) between pulmonary arterial hypertension (PAH) rats induced by left-to-right shunt and normotensive rats,and to study its possible role in the progress of PAH induced by high pulmanry blood flow.Methods Forty SD rats were randomly divided into 3 groups:control group (n =10),sham group (n =10),PAH model group (n =20).After molding,the rats were raised in the same condition for 11 weeks.Right ventricular systolic pressure (RVSP) of each rat was measured by right cardiac catheterization procedure.Right ventricular hypertrophy index (RVHI) was calculated.Single PASMC was obtained by acute enzyme separation method and the conventional whole-cell patch clamp technique was used to record the resting membrane potential (Em),ClCa and current density.The Ⅰ-Ⅴ curve between each group were compared.Results Compared with control group and sham group,the Ⅰ-Ⅴ curve about Itail of PAH model group was significantly shift downward; the difference between control group and sham group was not significant.There were positive correlations between Em and RVSP,RVHI (all P ＜ 0.01),and negative correlations between Itail and RVSP,RVHI and Em(all P ＜ 0.01).Conclusions During the formation process of left-to-right shunt induced PAH,with the step up of pulmonary arterial pressure,the Em of PASMCs stepping up.The absolute value of current density of inward ClCa currents was increased,and its Ⅰ-Ⅴ curve was shift downward.These suggest that the change of ClCa currents may play a role in the PAH induced by left-to-right shunting.
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Objective To investigate the effect of thrombospondin 1(TSP-1) on the cell proliferation of cultured rat pulmonary artery smooth cell (PASMCs) in vitro .Methods Rat PASMCs were cultured in vitro ,and treated with different concentrations (10-12 、10-11 、10-10 mol/L) of TSP-1 for 12 ,24 ,48 h .The cell proliferation was quantified by MTT assay .The cell cycle of PASMCs was measured by flow cytometric(FCM) analysis .Results MTT assay showed that TSP-1 promoted the proliferation of PASMCs significantly ,and the effect was concentration-dependent and time-dependent .FCM analysis indicated that TSP-1 increased the percentage of S phase .The percentage of S phase of PASMCs were increased after treated with thrombospondin-1 for 12 h , slight down after 24 h ,while reached a maximal level at 48 h .Conclusion The TSP-1 promotes rat PASMCs proliferation in a con-centration-dependent and time-dependent manner .
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Objective To explore the effects of hammerhead ribozyme on the expression and activity of NHE 1 and pHi in pulmonary artery smooth muscle cells (PASMCs) of rats and its role in PASMCs proliferation in vitro . Methods According to the secondary structure of NHE 1 mRNA in rats, NHE 1 specific hammerhead ribozyme was designed with the assistance of computer. The recombinant vector of retroviral plasmid pLXSN and hammerhead ribozyme, PRZ, was transfected into the cultured PASMCs. G418 resistant cell clones were screened with 100 ?g/ml G418. Then, the expression of NHE 1 mRNA was detected by RT PCR, intracellular pH(pHi) value and recovery rate of pHi after intracellular acid loading were measured by fluorescent probe BCECF. 22 Na uptake and 3H TdR incorporation were determined, respectively. Results Compared with the cells transfected with pLXSN and non transfected cells, NHE 1 mRNA, pHi value, pHi recovery rate, 22 Na uptake and 3H TdR incorporation decreased significantly in cells transfected with recombinant vector PRZ. No significance was found between the pLXSN transfected group and non transfected group. Conclusion Hammerhead ribozyme can cleave the target NHE 1 mRNA specifically, reduce the expression of NHE 1 mRNA, induce intracellular acidosis and consequently suppress the proliferation of PASMCs.
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Aim To investigate the changes of [Ca2+]i in the pulmonary artery smooth muscle cells of PAH rats induced by MCT.Methods PAH rat model was established by MCT intraperitoneal injection.The PASMCs were primarily cultured and loaded with Fura-2/AM.Effects of Ryanodine receptor agonists on intra-cellular calcium were measured by Fluorescence microscopy Results After being given 10 nmol?L-1 Ryanodine,the concentration of [Ca2+]i in control group increased by(93.31?12.41)nmol?L-1;and the concentration in PAH group increased by(141.71?13.59)nmol?L-1(P