Inhibitory Effect of PPARδAgonist GW501516 on Proliferation of Hypoxia-induced Pulmonary Arterial Smooth Muscle Cells by Regulating the mTOR Pathway

Objective This study aimed to investigate the effects of the peroxisome proliferator-activated receptorδ(PPARδ)agonist GW501516 on the proliferation of pulmonary artery smooth muscle cells(PASMCs)induced by hypoxia,in order to search for new drugs for the treatment and prevention of pulmonary vascular remodeling.Methods PASMCs were incubated with different concentrations of GW501516(10,30,100 nmol/L)under the hypoxic condition.The proliferation was determined by a CCK-8 assay.The cell cycle progression was analyzed by flow cytometry.The expression of PPARδ,S phase kinase-associated protein 2(Skp2),and cell cycle-dependent kinase inhibitor p27 was detected by Western blotting.Then PASMCs were treated with 100 nmol/L GW501516,100 nmol/L mammalian target of rapamycin(mTOR)inhibitor rapamycin and/or 2µmol/L mTOR activator MHY1485 to explore the molecular mechanisms by which GW501516 reduces the proliferation of PASMCs.Results The presented data demonstrated that hypoxia reduced the expression of PPARδin an oxygen concentration-and time-dependent manner,and GW501516 decreased the proliferation of PASMCs induced by hypoxia by blocking the progression through the G0/G1 to S phase of the cell cycle.In accordance with these findings,GW501516 downregulated Skp2 and upregulated p27 in hypoxia-exposed PASMCs.Further experiments showed that rapamycin had similar effects as GW501516 in inhibiting cell proliferation,arresting the cell cycle,regulating the expression of Skp2 and p27,and inactivating mTOR in hypoxia-exposed PASMCs.Moreover,MHY1485 reversed all the beneficial effects of GW501516 on hypoxia-stimulated PASMCs.Conclusion GW501516 inhibited the proliferation of PASMCs induced by hypoxia through blocking the mTOR/Skp2/p27 signaling pathway.

NR4A1 enhances glycolysis in hypoxia-exposed pulmonary artery smooth muscle cells by upregulating HIF-1αexpression

Background:Pulmonary arterial hypertension(PAH)is a chronic and progressive disease that is strongly associated with dysregulation of glucose metabolism.Alterations in nuclear receptor subfamily 4 group A member 1(NR4A1)activity alter the outcome of PAH.This study aimed to investigate the effects of NR4A1 on glycolysis in PAH and its underlying mechanisms.Methods:This study included twenty healthy volunteers and twenty-three PAH patients,and plasma samples were collected from the participants.To mimic the conditions of PAH in vitro,a hypoxia-induced model of pulmonary artery smooth muscle cell(PASMC)model was established.The proliferation of PASMCs was assessed using CCK8 assays.Results:Levels of NR4A1,hypoxia-inducible factor-1α(HIF-1α),and various glycolysis-related enzymes were measured.In addition,extracellular glucose and lactate production were assessed.The interaction between NR4A1 and HIF-1αwas evaluated by co-immunoprecipitation assays.Levels of NR4A1 and HIF-1αwas increased in PAH patients,and exposure to hypoxia resulted in increased levels of NR4A1 and HIF-1αin PASMCs.NR4A1 interacted with HIF-1α.NR4A1 overexpression enhanced hypoxia-induced expression of HIF-1α,GLUT1,PKM2,HK2,and CD36,decreased glucose levels,increased lactate levels and promoted hypoxic PASMC viability.Conversely,silencing NR4A1 decreased hypoxia-induced expression of HIF-1α,GLUT1,PKM2,HK2,and CD36,promoted glucose production,reduced lactate levels and inhibited hypoxic PASMC viability.Furthermore,overexpression of HIF-1αreversed the regulation of glycolysis caused by NR4A1 knockdown.Conclusion:NR4A1 enhances glycolysis in hypoxia-induced PASMCs by upregulating HIF-1α.Our findings indicate that the management of NR4A1 activity may be a promising strategy for PAH therapy.

Hypoxia promotes cell proliferation by modulating E2F1 in chicken pulmonary arterial smooth muscle cells

In this study,we sought to investigate the expression of the transcription factor E2F1 in chicken pulmonary arterial smooth muscle cells upon hypoxia exposure,as well as the role that E2F1 played in the regulation of cell proliferation.Isolated chicken pulmonary arterial smooth muscle cells were subjected to hypoxia or normoxia for indicated time points.Cell viability,DNA synthesis,cell cycle profile,and expression of E2F1 were analyzed.The results showed that hypoxia promoted cell proliferation and DNA synthesis which was accompanied by an increased S phase entry and upregulation of E2F1 at mRNA and protein levels.Using siRNA technology,we demonstrated that gene inactivation of endogenous E2F1 abolished hypoxia-induced cell proliferation,DNA synthesis,and S phase entry compared with negative siRNA transfected cells.These results suggest that hypoxia-induced proliferation is mediated by inducing E2F1 in chicken pulmonary arterial smooth muscle cells.

Oxidative modification of high density lipoprotein induced by cultured human arterial smooth muscle cells

Objective: To observe the oxidative modification of high density lipoprotein (HDL) induced by cultured human arterial smooth muscle cells (SMCs). Methods: HDL cocultured with SMCs at 37℃ in 48 h was subjected, and native HDL (N-HDL) served as control. Oxidative modification of HDL was identified by using agarose gel electrophoresis. Absorbances of conjugated diene (CD) and lipid hydroperoxide (LOOH) were measured with ultraviolet spectrophotometry at 234 and 560 nm respectively, and fluorescence intensity of thiobarbuturic acid reaction substance (TBARS) with fluorescence spectrophotometry at 550 nm emission wavelength with excitation at 515 nm. Results: In comparison with N-HDL, the electrophoretic mobility of SMCs-cocultured HDL was increased, and the contents of CD, LOOH and TBARS HDL were very significantly higher than those of the control HDL (P<0.01). Conclusion: Oxidative modification of HDL can be induced by human arterial SMCs.

The inhibitory effect of endogenous opioid peptide on the proliferation of pulmonary arterial smooth muscle cells

To investigate the effects of endogenous opioid peptides L-enkephalin (L-Enk) and morphine on the proliferation of pulmonary arterial smooth muscle cells (PASMCs) and analyze their mechanism. Methods: Rabbit PASMCs cultured invitro, MTT method and 3 H-TdR incoporation were Used. Results: 1×10-3 -1×10-4 mol/L L-Enk markedly inhibited the proliferation and the DNA synthesis of PALMCs, which could be reversed by naloxone, an opioid receptor antagonist, while orphineseemed to have no obvious effects on the proliferation and the DNA synthesis of PASMCs. Conclusion: Endogenous opioid peptidecan inhibit the proliferation and DNA synthesis of PASMCs, which is mainly mediated through opioid δ receptor and not opioid μreceptor.

Iptakalim, a novel ATP-sensitive potassium channel opener, inhibits pulmonary arterial smooth muscle cell proliferation by downregulation of PKC-α

Iptakalim is a new ATP-sensitive potassium （KATp） channel opener, and it inhibits the proliferation of pulmonary arterial smooth muscle cells （PASMCs） and pulmonary vascular remodeling. However, the underlying mechanism remains unclear. In the present study, we found that iptakalim significantly decreased pulmonary artery pressure, inhibited pulmonary ariery remodeling and PKC-α overexpression in chronic hypoxia in a rat pulmonary hypertension model. Iptakalim reduced hypoxia-induced expression of PKC-α, and abolished the effect of hypoxia on PASMC proliferation significantly in a dose-dependent manner in vitro. Moreover, these effects were abol- ished by glibenclamide, a selective KArp channel antagonist. These results indicate that iptakalim inhibits PASMC proliferation and pulmonary vascular remodeling induced by hypoxia through downregulating the expression of PKC-α. Iptakalim can serve as a novel promising treatment for hypoxic pulmonary hypertension.

Efficient differentiation of vascular smooth muscle cells from Wharton's Jelly mesenchymal stromal cells using human platelet lysate: A potential cell source for small blood vessel engineering

BACKGROUND The development of fully functional small diameter vascular grafts requires both a properly defined vessel conduit and tissue-specific cellular populations.Mesenchymal stromal cells(MSCs) derived from the Wharton's Jelly(WJ) tissue can be used as a source for obtaining vascular smooth muscle cells(VSMCs),while the human umbilical arteries(h UAs) can serve as a scaffold for blood vessel engineering.AIM To develop VSMCs from WJ-MSCs utilizing umbilical cord blood platelet lysate.METHODS WJ-MSCs were isolated and expanded until passage(P) 4. WJ-MSCs were properly defined according to the criteria of the International Society for Cell and Gene Therapy. Then, these cells were differentiated into VSMCs with the use of platelet lysate from umbilical cord blood in combination with ascorbic acid,followed by evaluation at the gene and protein levels. Specifically, gene expression profile analysis of VSMCs for ACTA2, MYH11, TGLN, MYOCD, SOX9,NANOG homeobox, OCT4 and GAPDH, was performed. In addition,immunofluorescence against ACTA2 and MYH11 in combination with DAPI staining was also performed in VSMCs. HUAs were decellularized and served as scaffolds for possible repopulation by VSMCs. Histological and biochemical analyses were performed in repopulated h UAs.RESULTS WJ-MSCs exhibited fibroblastic morphology, successfully differentiating into"osteocytes", "adipocytes" and "chondrocytes", and were characterized by positive expression(> 90%) of CD90, CD73 and CD105. In addition, WJ-MSCs were successfully differentiated into VSMCs with the proposed differentiation protocol. VSMCs successfully expressed ACTA2, MYH11, MYOCD, TGLN and SOX9. Immunofluorescence results indicated the expression of ACTA2 and MYH11 in VSMCs. In order to determine the functionality of VSMCs, h UAs were isolated and decellularized. Based on histological analysis, decellularized h UAs were free of any cellular or nuclear materials, while their extracellular matrix retained intact. Then, repopulation of decellularized h UAs with VSMCs was performed for 3 wk. Decellularized h UAs were repopulated efficiently by the VSMCs. Biochemical analysis revealed the increase of total hydroyproline and s GAG contents in repopulated h UAs with VSMCs. Specifically, total hydroxyproline and s GAG content after the 1 st, 2 nd and 3 rd wk was 71 ± 10, 74 ± 9 and 86 ± 8 μg hydroxyproline/mg of dry tissue weight and 2 ± 1, 3 ± 1 and 3 ± 1μg s GAG/mg of dry tissue weight, respectively. Statistically significant differences were observed between all study groups(P<0.05).CONCLUSION VSMCs were successfully obtained from WJ-MSCs with the proposed differentiation protocol. Furthermore, h UAs were efficiently repopulated by VSMCs. Differentiated VSMCs from WJ-MSCs could provide an alternative source of cells for vascular tissue engineering.

The Effect of Erigeron Breviscapus on Proliferation of Pulmonary Artery Smooth Muscle Cells in Hypoxic Porcines

In order to study the effect of Erigeron Breviscapus (EB) on proliferation of pulmonary artery smooth muscle cells (PASMC) in hypoxic porcines, immunohistochemical and MTT methods were employed to measure the proliferation of PASMC. It was found that the proliferation of PASMC in porcines was obvious, and the expression of proliferating cell nuclear antigen (PCNA) was significantly high within 48 h after exposure to hypoxia. The EB could inhibit the proliferation and the expression of PCNA in PASMC under hypoxia, but it had no effect on the proliferation and expression of PCNA in PASMC under normal condition. The EB could inhibit the proliferation and the expression of PCNA in PASMC induced by phorbol 12-myristate 13-acetate (PMA), an agonist of PKC in normal and hypoxic conditions. It was concluded that the hypoxia could enhance the proliferation and expression of PCNA in PASMC. The EB can inhibit the proliferation and expression of PCNA in PASMC under hypoxia through PKC-signal way. The EB may be used in treating the pulmonary hypertension by inhibiting the proliferation of PASMC and the pulmonary vascular remodeling.

Hypoxia Down-regulates Secretion of MMP-2, MMP-9 in Porcine Pulmonary Artery Endothelial and Smooth Muscle Cells and the Role of HIF-1

Summary： Primary cell culture, techniques of gene transfection, gelatin zymography, and Western blot were used to investigate the effect of hypoxia on the secretion of MMP 2 and MMP-9 in pulmonary artery endothelial cells （PAEC） and smooth muscle cells （PASMC）, and the role of HIF-1. Our results showed that （1） after exposure to hypoxia for 24 h, the protein content and activity of MMP-2 in the PAEC medium as well as these of MMP-2 and MMP-9 in PASMC medium （P〈0. 01 ） decreased significantly in contrast to those in normoxic group （P（0.05） ; （2） after transfection of wild type EPO3＇ enhancer, a HIF-1 decoy, the content and activity of MMP 2 and MMP-9 in hypoxic mediums became higher than those in normoxic group （P〈0. 01）, while transfection of mutant EPO3＇-enhancer didn＇t affect the hypoxia-induced down-regulation. It is concluded that hypoxia could inhibit the secretion and activity of MMP 2 and MMP-9 in PAEC and PASMC, which could he mitigated by the transfection of EPO3 ＇-enhancer and that H1F-1 pathway might contribute to hypoxia-induced down regulation of MMP-2 and MMP-9.

Effects of calcium-activated chloride channels on proliferation of pulmonary artery smooth muscle cells in rats under chronic hypoxic condition

Objective：To investigate the effects of calcium-activated chloride （ClCa） channels on proliferation of pulmonary artery smooth muscle cells（PASMCs） in rats under chronic hypoxic condition. Methods：The cultured PASMCs were placed under normoxic and chronic hypoxic conditions：The cells were observed by light and electron microscope; The cell cycles were observed by flow-cytometry; Immunocytochemistry staining was used to detect the expressions of PCNA, c-fos and c-jun of PASMCs; Cytoplasmic free Ca^2＋ concentration （[Ca^2＋]i） in PASMCs was investigated by fluorescent quantitation using fluorospectrophotometer. Results：The PASMCs were contractile phenotype under normoxic conditions. Observation by transmission electron microscope： In kytoplasm of contractile phenotype cells, myofilament bundles were abundant and the content of cell organs such as Golgi＇s bodies were rare. The PASMCs were synthetic phenotype under chronic hypoxic condition. There were increased free ribosomes, dilated rough endoplasmic reticulums, highly developed Golgi complexes, decreased or disappeared thick filaments and dense body in kytoplasm of synthetic phenotype cells. After NFA and IAA-94, the situations were reversed The number of S ＋G2M PASMCs were significantly increased in chronic hypoxic condition; The NFA and IAA-94 were shown to significantly decrease them from （28.6±1.0）% to （16.0±1.6）% and the number of G0G1 PASMCs significantly increased from （71.4± 1.9）% to （83.9 ± 1.6）% （P〈 0.01）. In chronic hypoxic conditions, the expression of proliferating cell nucleus antigen was significantly increased; The NFA and IAA-94 were shown to significantly decrease it from （81 ± 6）% to （27 ± 7）%（P 〈 0.01）. The expression of c-fos and c-jun were significantly increased in＇chronic hypoxic conditions; The NFA and IAA-94 were shown to significantly decrease them from 0.15 ±0.02, 0.32 ± 0.05 to 0.05 ± 0.01, 0.12 ± 0.05, respectively （P〈 0.01）; Under chronic hypoxic conditions, [Ca^2＋]i was increased; The NFA and IAA-94 decreased it from （281.8±16,5）nmol/L to （117.7 ± 15.4）nmol/L（P 〈 0.01）. Conclusion：Hypoxia initiated the change of PASMCs from contractile to synthetic phenotype and increased proliferation of PASMCs. NFA and IAA-94 depressed cell proliferation by blocking ClCa channels in hypoxic condition. These may play an important role in proliferation of PASMCs under chronic hypoxic conditions.

Involvement of TRPC1 and Cyclin D1 in Human Pulmonary Artery Smooth Muscle Cells Proliferation Induced by Cigarette Smoke Extract

Cigarette smoking contributes to the development of pulmonary artery hypertension(PAH).As the basic pathological change of PAH,pulmonary vascular remodeling is considered to be related to the abnormal proliferation of pulmonary artery smooth muscle cells(PASMCs).However,the molecular mechanism underlying this process remains not exactly clear.The aim of this research was to study the molecular mechanism of PASMCs proliferation induced by smoking.Human PASMCs(HPASMCs)were divided into 6 groups:0%(control group),cigarette smoking extract(CSE)-treated groups at concentrations of 0.5%,1%,2%,5%,10%CSE respectively.HPASMCs proliferation was observed after 24 h.HPASMCs were divided into two groups:0(control group),0.5%CSE group.The mRNA and protein expression levels of transient receptor potential channel 1(TRPC1)and cyclin D1 in HPASMCs after CSE treatment were respectively detected by RT-PCR and Western blotting.The intracellular calcium ion concentration was measured by the calcium probe in each group.In the negative control group and TRPC1-siRNA transfection group,the proliferation of HPASMCs and the expression of cyclin D1 mRNA and protein were detected.Data were compared with one-way ANOVA(for multiple-group comparison)and independent t-test(for two-group comparison)followed by the least significant difference(LSD)test with the computer software SPSS 17.0.It was found that 0.5%and 1%CSE could promote the proliferation of HPASMCs(P<0.05),and the former was more effective than the latter(P<0.05),while 3%and above CSE had inhibitory effect on HPASMCs(P<0.05).The mRNA and protein expression levels of TRPC1 and cyclin D1 in 0.5%and 1%CSE groups were significantly higher than those in the control group(P<0.05),while those in 3%CSE group were significantly decreased(P<0.05).Moreover,the proliferation of HPASMCs and the expression of cyclin D1 mRNA and protein in TRPC1-siRNA transfection group were significantly reduced as compared with those in the negative control group(P<0.05).It was concluded that low concentration of CSE can promote the proliferation of HPASMCs,while high concentrations of CSE inhibit HPASMCs proliferation.These findings suggested that CSE induced proliferation of HPASMCs at least in part via TRPC1-mediated cyclin D1 expression.

EFFECT OF HYPOXIA ON DNA SYNTHESIS AND C－MYC GENE EXPRESSION OF PULMONARY ARTERY SMOOTH MUSCLE CELLS

The neonate is particularly susceptible to the development of hypoxic pulmonary hypertension. The present study was undertaken to observe the effect of hypoxia on DNA synthesis and c-myc gene expression between newborn calf and adult bovine PASMC in vilro. DNA synthesis measured by 3H- TdR incorporation was increased after hypoxic challenge for 24h. Hypoxia enhanced the increment in 3H-TdR incorporation induced by EGF. Northern blot analysis revealed that PASMC cultured in both normoxia and hypoxia expressed c- myc gene transcript of 2. 2Kb ,but there is a higher 2. 2Kb mRNA expression in hypoxic PASMC than that in normoxia. We speculate that newborn calf PASMC exhibited potential response to hypoxia than adult,which was augmented by EGF. Enhanced c-myc gene expression may lead to a great understanding of the mechanism of PASMC growth in the development of pulmonary hypertension.

Effects of NHE-1 ribozyme gene transfection on apoptosis of rat pulmonary artery smooth muscle cells in vitro

Objective : To investigate the effects of the transfection of NHE-1 ribozyme gene on the apoptosis of pulmonary artery smooth muscle cells (PASMC) in vitro. Methods: After NHE-1 ribozyme gene was designed, synthesized and then cloned into plasmid pLXSN, the recombined plasmid was tansfected into cultured rat PASMC. Expression of NHE-1 mRNA was detected with semi-quantitative RT-PCR. Intracellular pH (pHi) was measured by using fluorescence dye BCECF-AM. Cell cycle was measured with aid of flow cy-tometric DNA analysis. Cell apoptosis was observed with electron microscopy and terminal deoxynucleotidyl transferase-mediated dUTP nick end labelling (TUNED respectively. Results: The NHE-1 mRNA expression level and pHi value were significantly lower in PASMCs transfected with NHE-1 ribozyme gene than those transfected with pLXSN or without transfection. Meanwhile, the apoptosis rate of cells transfected with NHE-1 ribozyme gene was increased significantly. Morphology of cell apoptosis was observed in the cells transfected with NHE-1 ribozyme gene under an electron microscope. Conclusion: The transfection of NHE-1 ribozyme gene induces the apoptosis of PASMCs by inhibiting NHE-1 expression and intracellular acidification.

Immuohistochemical study on smooth muscle cell proliferation, pheno-typic modulation, and extracellular matrix accumulation in venous arterial grafts in rabbits

Objective: To study the kinetics and distribution of smooth muscle cell (SMC) proliferation, phe-notypic modulation, and various extracellular matrix (ECM) components accumulation during vein graft remodeling. Methods: Normal vein and vein graft in carotid arteries were examined on d 4, d 7, d 14, d 60 and d180 after bypass grafting with immunohistochemical markers of cellular proliferation (proliferating cell nuclear antigen, PCNA), cytoskeletal protein production (a-actin SMC), myosin heavy chain (MHO iso-forms, ECM proteins, and histochemistry (hematoxylin eosin and Elastica-van Gieson stain). Results: Normal veins demonstrated an extremely low level of cellular proliferation and expressed as adult phenotype SM-Cs in media. After bypass grafting, medial SMCs in the graft appeared to be damaged and began to proliferate on d 4, and subsequently migrated and formed the neointima on d 7. Thereafter, the neointima thickened throughout the 180-day period of the experiment, although the neointimal SMC proliferation decreased after d 14. Meanwhile SMCs underwent a distinct phenotypic change from normal adult type to embryonic type. On d 60, embryonic phenotype SMCs began to return to the adult phenotype, but remain to be present in the neointima for as long as 180 d. ECM components including type I collagen, heparin sulfate proteoglucan (HSPG), and dermatan sulfate proteoglcan (decorin) were detected within the neointima on d 7. Thereafter, the accumulation of ECM increased progressively with time. On d 180, a large amount of ECM components were found in the neointima. HSPG mainly accumulated in the superficial and cellular region of the neointima , decorin, on other hand, located in hypocellular area deep in neointima. Type I collagen scatted in both regions. The elastic fibers became rich and arranged continuously in the neointima. Conclusion: The neointima of vein graft was initially formed by proliferation of the embryonic-type SMCs and then thickened infinitely due to ECM accumulation. Prolonged existence of the embryonic-type SMCs in the neointima may contribute to ECM accumulation and increase in the neointima thickness infinitely, which may predispose accelerated stenosis in the vein graft.

Iododeoxyuridine uptake in proliferating smooth musc le cells:an in vitro model to assess drug effects on intimal hyperplasia

Purpose To assess the maximum uptake of Iododeo xyur idine (IUdR) by proliferating smooth muscle cells in vitro to determine the opti mal concentration to be administrated in an in vivo experiment. The long-term g oal is to utilize radioactive IUdR to inhibit smooth muscle cell proliferation a nd restenosis of arteries after balloon angioplasty in vivo. Methods Porcine smooth muscle cells (SMCs) were cultured in 5% FBS medium and stim ulated to proliferate by the addition of medium containing 10% FBS and insulin. IUdR was added at 5 μM, 10 μM, 20 μM, 30 μM, 40 μM, respectively, in prolif erating SMCs with control for 1, 3, 5, 7 day incubation. Fluorescence Activated Cell Scanning (FACS) was performed after the SMCs were harvested and double-sta ined with FITC-conjugated anti-IUdR antibody (B44) and propidium iodide (PI). The ratio of IUdR-labeled cells to total cell population for each IUdR concentr ation and duration was determined by FACS. All data were repeated three times at each time point. The doubling times, growth curve and cell density of the proli ferating SMCs were investigated using Beckman Coulter Particle Counter and digit al microscopy. Results The percentage of proliferating SMCs uptaking IUdR incr eased from 1 to 5 days incubation with all concentrations of IUdR; In day 5, the uptake rate reached the peak value, then decreased by 7 days. IUdR uptake on d ay 5 was higher with concentrations of 10 μM and 20 μM. The doubling times of the SMCs were prolonged with IUdR concentration increasing, while the proliferat ing cell number and density compared with control decreased obviously by day 5 ( P<0.05).Conclusion The peak time to uptake IUdR was 5 days and optimal concentration of IUdR was between10 μM to 20 μM for proliferating SMCs to upta ke in vitro. IUdR itself could inhibit the SMCs’ proliferation and the inhibito ry effect was related to the concentration.[

DL0805 derivatives protect the pulmonary arterial cells via the RhoA/ROCK pathway

OBJECTIVE Pulmonary artery hypertension(PAH)is a severe disease characterized by the mean pulmonary artery pressure exceeding 25 mm Hg at rest.PAH could induce right heart failure and has a very high mortality rate.At present,several kinds of drugs have been used in the treatment of PAH.However,most of these drugs aim to relax pulmonary arteries and do not inhibit the injury of vessels.In other words,the drugs available for PAH treatment do not improve the survival rate of PAH patients and cannot satisfy the needs in clinic.To discover and develop novel candidate compounds effective on the treatment of pulmonary artery injury and remodeling will be very important.Based on these background,the present study aimed to study the protective effect of two novel Rho-kinases(Rho-associated coiledcoil forming protein serine/threonine kinase,ROCK)inhibitors,DL0805 derivatives(DL0805-1and DL0805-2),on pulmonary arterial cells and further evaluate the underlying mechanisms and the possibility of DL0805 derivatives become therapeutic drugs for PAH.METHODS The primary cultured pulmonary arterial cells including human pulmonary artery endothelium cells(HPAECs)and human pulmonary artery smooth muscle cells(HPASMCs)were used in this study.HPAECs were injured under hypoxia environment(1%O2)and treated with or without DL0805 derivatives.After 48 h,the proliferation and oxidative stress were observed.CCK8 was used to detect cell viability.DCFH-DA was used as probe for reactive oxygen species(ROS)under fluorescence imaging system.HPASMCs was stimulated by growth factors including platelet-derived growth factor-BB(PDGF-BB)and Fetal Bovine Serum(FBS).The proliferation was observed in the cells treated with or without DL0805 derivatives.HPASMCs treated with or without DL0805 derivatives were further incubated with endothelin(ET-1),the proliferation and cytoskeleton remodeling of cells were detected by immunofluorescence assay.At last,Western blotting(WB)and immunofluorescence assay were employed to analysis the underlying mechanisms in the above experiments.RESULTS 10μmol·L-1DL0805-2 could inhibit the proliferation of HPAECs induced by hypoxia.Each concentration of DL0805-1 and DL0805-2attenuated the production of ROS in HPAECs.Results from WB indicated that DL0805 derivatives decreased the injury of HPAECs induced by hypoxia through the inhibition of the expression of Rho A and the activity of ROCK.On HPASMCs,DL0805 derivatives reduced the proliferation induced by PDGF-BB and FBS and inhibited cytoskeleton remodeling induced by ET-1.Immunofluorescence assay showed that DL0805 derivatives inhibited ROCK activity and down regulated the phosphorylation levels of ROCK substrates.CONCLUSION DL0805derivatives exhibited protective effect on pulmonary arterial cells including endothelium cells and smooth muscle cells.Among the above experiments,DL0805-2 showed stronger potency than DL0805-1.These two compounds might protect the cells through the inhibition of Rho A/ROCK pathway and they probably have the potential in the treatment of PAH and deserve further evaluation.

虎杖苷调节YAP1/TAZ信号通路对缺氧性肺动脉高压新生大鼠肺动脉平滑肌细胞增殖与凋亡的影响

目的 探究虎杖苷(PD)对缺氧性肺动脉高压(HPH)新生大鼠肺动脉平滑肌细胞(PASMCs)增殖与凋亡的影响及其作用机制。方法 将新生大鼠随机分为6组:对照组、模型组、PD低剂量组、PD中剂量组、PD高剂量组、PD高剂量+Hippo通路抑制剂(PD高剂量+XMU-MP-1)组,每组10只。缺氧2周后,检测各组大鼠右心室收缩压(RVSP)和右心室肥厚指数(RVHI),苏木精-伊红(HE)染色观察肺组织病理学变化,并计算肺动脉管壁厚度占总厚度的百分比(WT%)和管壁面积占总面积的百分比(WA%)。分离各组新生大鼠PASMCs,分为NC组、低氧(Hypoxia)组、PD低剂量组、PD中剂量组、PD高剂量组、PD高剂量+XMU-MP-1组。CCK-8和EdU检测细胞增殖,流式细胞术检测细胞凋亡,免疫印迹(Western blot)检测肺组织和PASMCs中Yes相关蛋白1(YAP1)、PDZ结合域的转录共刺激因子信号通路(TAZ)、哺乳动物不育系20样激酶1(MST1)、B细胞淋巴瘤-2(Bcl-2)、Bcl-2相关蛋白(Bax)蛋白表达。结果 与对照组相比,模型组大鼠肺动脉管壁明显增厚,管腔变窄,RVSP、RVHI、WT%、WA%、YAP1、MST1、TAZ蛋白表达显著升高(均P<0.05);与模型组相比,PD低、中、高剂量组大鼠肺动脉增厚减少,管腔变大,RVSP、RVHI、WT%、WA%、YAP1、MST1、TAZ蛋白表达显著降低,且PD各组间差异存在剂量依赖性(均P<0.05);XMU-MP-1可逆转这一结果。与NC组相比,Hypoxia组细胞A_(450nm)值、EdU阳性率、YAP1、MST1、TAZ、Bcl-2蛋白表达显著升高,凋亡率、Bax蛋白表达显著降低(均P<0.05);与Hypoxia组相比,PD低、中、高剂量组细胞A_(450nm)值、EdU阳性率、YAP1、MST1、TAZ、Bcl-2蛋白表达显著降低,凋亡率、Bax表达显著升高,且PD各组间有剂量依赖性(均P<0.05);XMU-MP-1可逆转这一结果。结论 PD可能通过抑制YAP1/TAZ信号通路抑制HPH新生大鼠PASMCs增殖,促进凋亡。

PI3K/Akt/FoxO1信号通路对人源肺动脉平滑肌细胞及肺动脉高压大鼠细胞凋亡的影响

目的探究磷脂酰肌醇3-激酶(PI3K)/蛋白激酶B(Akt)/叉头框蛋白O1(FoxO1)信号通路对人源肺动脉平滑肌细胞(hPASMC)及肺动脉高压大鼠细胞凋亡的影响。方法细胞实验部分,将hPASMC分为4组:(1)空白对照组;(2)血小板源性生长因子-BB(PDGF-BB)组;(3)PDGF-BB+LY294002组;(4)PDGF-BB+紫杉醇(paclitaxel)组。采用TUNEL检测细胞凋亡,采用蛋白质印迹法检测Bcl-2、裂解的胱天蛋白酶-3(cleaved caspase-3)和PI3K/Akt/FoxO1信号通路相关蛋白表达水平。动物实验部分,将12只SD大鼠随机分为4组:(1)空白对照组;(2)野百合碱(MCT)组;(3)MCT+LY294002组;(4)MCT+paclitaxel组。采用Western blot检测Bcl-2、cleaved caspase-3和PI3K/Akt/FoxO1信号通路相关蛋白表达水平。结果细胞实验部分:相比于PDGF-BB组,PDGF-BB+LY294002组与PDGF-BB+paclitaxel组的Bcl-2表达水平下降(P<0.01),cleaved caspase-3表达水平上升(P<0.01);相比于空白对照组,PDGF-BB+LY294002组与PDGF-BB+paclitaxel组的凋亡率增加(P<0.01)。动物实验部分:相比于MCT组,MCT+LY294002组与MCT+paclitaxel组Bcl-2、磷酸化Akt与磷酸化FoxO1表达水平下降(P<0.01),cleaved caspase-3与FoxO1表达水平上升(P<0.01)。各组之间PI3K表达水平无显著差异。结论PI3K/Akt/FoxO1信号通路抑制hPASMC与肺动脉高压大鼠肺组织的细胞凋亡。

沉默TUFM通过AMPK/mTOR信号通路调控线粒体自噬对肺源性心脏病模型大鼠肺动脉高压的影响

目的探讨线粒体翻译延伸因子Tu(TUFM)通过线粒体自噬促进肺动脉高压(PAH)血管重塑的作用机制。方法2022年1月—2023年6月于辽宁省人民医院中心实验室进行实验。将36只健康雄性Sprague-Dawley大鼠随机分为空白对照(Ctrl)组、模型(PAH)组、TUFM过表达(OE)组、OE阴性对照(OE-NC)组、短发夹RNA(Sh)敲除TUFM(Sh)组和Sh-NC阴性对照(Sh-NC)组,每组6只。除Ctrl组外,其余大鼠均一次性腹腔注射1%野百合碱(60 mg/kg)诱导心源性肺水肿PAH大鼠模型;大鼠肺动脉平滑肌细胞(PASMC)在低氧(3%O 2)条件下培养24 h模拟体内肺动脉高压微环境,分为常氧(Norm)组、低氧(Hyp)组、小干扰RNA(SiRNA)-1组、SiRNA-2组、Si-NC组、OE-NC组和OE组。右心导管插管和脉冲多普勒超声检测大鼠肺血流动力学;苏木素-伊红染色检测肺小动脉病理结构;免疫荧光共染检测TUFM组织定位;细胞计数法检测细胞增殖;透射电镜观察线粒体结构和自噬小体;蛋白免疫印迹检测TUFM、自噬、凋亡和磷酸腺苷活化蛋白激酶(AMPK)/哺乳动物雷帕霉素靶蛋白(mTOR)通路相关蛋白表达。结果与Ctrl组比较,PAH组大鼠TUFM蛋白表达升高,且主要与PASMC标志物α平滑肌肌动蛋白(α-SMA)在肺小动脉内膜存在共定位,而与内皮细胞标志物CD31无共定位,肺动脉收缩压(PASP)升高,肺动脉血流加速时间(PAAT)缩短,远端肺小动脉管壁呈向心性增厚,管腔狭窄几乎堵塞,TUFM、苄氯素1重组蛋白(BECN1)、人微管相关蛋白轻链3(LC3)II/I和B淋巴细胞瘤2(Bcl2)蛋白表达升高,P62、Bcl2相关X蛋白(Bax)和凋亡酶激活因子(Apaf)蛋白表达降低(P<0.05);与PAH组比较,OE组PASP升高,PAAT缩短,肺小动脉管壁厚度升高,肺动脉TUFM、BECN1、LC3II/I和Bcl2表达升高,P62、Bax和Apaf表达降低(P<0.05);与PAH组比较,Sh组PASP降低,PAAT延长,肺小动脉管壁厚度和管腔狭窄度有所改善,TUFM、BECN1、LC3II/I和Bcl2表达降低,P62、Bax和Apaf表达升高(P<0.05)。与Norm组比较,Hyp组PASMC细胞TUFM蛋白表达升高;与Si-NC组细胞相比,SiRNA-1和SiRNA-2组P62、Bax蛋白表达升高,BECN1、LC3II/I、Bcl2、TUFM表达降低,线粒体结构完整,PASMC细胞增殖活性降低,细胞p-AMPK表达降低,p-mTOR表达升高(P<0.05);与OE-NC组比较,OE组细胞P62和Bax蛋白表达降低,BECN1、LC3II/I、Bcl2和TUFM表达升高,部分线粒体损伤崩解,嵴断裂消失,PASMC细胞增殖活性明显升高,细胞p-AMPK表达升高,p-mTOR表达降低(P<0.05)。结论沉默TUFM可通过激活AMPK/mTOR信号通路促进线粒体自噬加速PAH肺动脉平滑肌细胞凋亡。

枸橼酸镁对慢性肾衰竭环境下氧化应激的抑制作用

目的探讨枸橼酸镁(magnesium citrate,MgCit)抑制慢性肾衰竭(chronic renal failure,CRF)环境下氧化应激的作用。方法SD大鼠分为CRF模型组、MgCit组(375、750 mg/kg),另设正常对照组、MgCit对照组(750 mg/kg);透射电镜观察大鼠胸大动脉血管平滑肌细胞(vascular smooth muscle cells,VSMCs)中线粒体形态;利用试剂盒检测大鼠主动脉和血浆中超氧化物歧化酶(superoxide dismutase,SOD)和丙二醛(malonaldehyde,MDA)的含量。培养VSMCs并分为正常对照组、CRF模型组、MgCit组(1.5、3 mmol/L),流式细胞仪定量检测细胞超氧化物阴离子(dihydroethidium,DHE)和细胞凋亡情况。结果与对照组相比,模型组大鼠胸大动脉VSMCs线粒体肿胀,嵴断裂或消失;MgCit干预能减轻线粒体肿胀,未见嵴断裂;模型组大鼠主动脉和血浆SOD水平降低(P<0.05),MDA水平升高(P<0.05);MgCit干预能增加主动脉和血浆SOD水平,并降低MDA水平(P<0.05)。CRF环境下即CRF模型组VSMCs的DHE含量升高,凋亡增加(P<0.05);MgCit干预能降低DHE含量,并抑制凋亡(P<0.05)。结论MgCit抑制CRF大鼠和VSMCs的氧化应激水平。