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AIM:Increasing evidence suggests that carbohydrate-binding proteins play an essential role in tumor growth and metastasis .Ga-lectin-3, a multifunctional protein of an expanding family of β-galactoside-binding animal lectins , is the major nonintegrin cellular laminin-binding protein , and is implicated in a variety of biologic events , such as inflammation and angiogenesis .Because galectin-3 expression was shown to participate in mediating tumor angiogenesis and initiate signaling cascades in several diseases .We hypothe-sized that galectin-3 may promote pulmonary vascular endothelial neovascularization .METHODS:Hypoxic and MCT rat model of pul-monary artery remodeling was used .The mRNA and protein levels of galectin-3 in rats were measured by in situ hybrization and West-ern blot analysis.Endothelial cell (EC) proliferation, migration and tube formation were measured using MTT , cell scratch and Matri-gel assays, respectively.Protein expression was quantitated by Western blot analysis .LC 3A/B staining was detected with cellular im-munofluorescence staining .RESULTS:We found that galectin-3 was localized on the intima and adventitial wall .Galectin-3 was in-creased after rat hypoxia and MCT administration .Galectin-3 promoted EC proliferation , migration and tube formation , while its roles were reversed by RNA interference.Galectin-3 induced Atg 5, Beclin-1, LAMP-2, and LC 3A/B expression increases.Galectin-3 al-so increased LC 3A/B staining in ECs.Akt/mTOR and GSK-3βsignaling pathways were activated after galectin-3 treated ECs using its specific phosphorylation antibodies , while blocked it with LY294002 inhibited cell autophagy and EC dynamic alterations induced by galectin-3.CONCLUSION:These findings demonstrate that galectin-3 can induce an Akt signaling cascade leading to cell autoph-agy, and then the differentiation and angiogenesis of pulmonary artery endothelial cells .
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Aim To investigate the effect of 15-ketoeicosatetraenoic acid(15-KETE)and its mechanism through ion channels on rat isolated pulmonary arterial rings by using organ bath technique.Methods Sixteen healthy Wistar rats weighing 220?20 g were divided into two groups(n=8): normoxia group breathing fresh air(FiO_2=21%) and hypoxia group breathing hypoxic air(FiO_2=10%) in a hypoxic box.Pulmonary arteries(PA)were extracted after 9 d and cut into rings(0.5~1.0 mm in diameter and 3 mm in length) for organ bath experiments.Results(1) With increasing concentration from 0 to10~(-6) mol?L~(-1),15-KETE increased PA rings tension gradually in a dosedependent fashion;(2) 4-aminopyridine(2 mmol?L~(-1)),a Kv channel blocker significantly decreased constriction of rat isolated PA rings induced by 15-KETE,and results were similar in two groups;(3) The K_(ATP) channel blocker glyburide(10~(-6)6 mol?L~(-1)) and the BK_(Ca) channel blocker tetraethylammonium(10 mmol?L~(-1)) did not affect constriction of rat isolated PA rings induced by 15-KETE;(4) The BKCa channel blocker nifedipine(10~(-6) mol?L~(-1)) and Ca~(2+)-free Krebs solution significantly decreased constriction of rat isolated PA rings induced by 15-KETE.Conclusion Kv channels play a role in constriction of PA induced by 15-KETE;L-type Ca~(2+) channel blocker and extracellular calcium ion also influence constriction of isolated PA rings induced by 15-KETE.
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Aim To evaluate the effect of 15-hydroxy eicosatetraenoic acid(15-HETE) on the tension of isolated internal carotid artery(ICA) rings in normoxic or hypoxic rats in order to find out the pathophysiological effect of 15-HETE in ischemic/hypoxic brain tissues.Methods Sixteen healthy Wistar rats were randomly divided into two groups(n=8): group A with normal oxygen supply(FiO_2 21%) and group B with hypoxia(FiO_2 10%).9 days later,the rats were killed and the ICA rings were prepared.15-HETE in different concentration were added accordingly,and the after washing up,blockers of different kinds of K~+ channels such as 2 mmol?L~(-1) 4-AP,10~(-2) mol?L~(-1) TEA and 10~(-6) mol?L~(-1) GLYB were added to the KH solution separately,followed by the administration of 10~(-6) mol?L~(-1) 15-HETE.The isometric tension was recorded using a four-channel force-displacement transducer.Results The ICA tension was significantly increased both in groups A and B by 15-HETE in concentration-dependent manner(P0.05,n=8).Furthermore,10~(-2) mol?L~(-1) TEA,10~(-6) mol?L~(-1) GLYB had little effects on the tension of rings.Application of 10~(-6) mol?L~(1) 15-HETE after administration of TEA or GLYB induced nearly the same increase in ICA tone as it happened in the group administered with 10~(-6)mol?L~(-1) 15-HETE alone.Conclusion 15-HETE can induce brain vasoconstriction especially under the hypoxic condition.Voltage-dependent potassium channels play an important role in 15-HETE induced constriction.
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Aim To test the contribution of 15-HETE on expression of KV1.5 channel under hypoxia condition,using CDC or NDGA to block 15-LO/15-HETE,and to observe the effect of hypoxia on KV1.5 channel protein,mRNA expressions in cultured rat pulmonary arterial smooth muscle cells(PASMCs)and pulmonary arterials(PAs).Methods Western blot,RT-PCR and 15-LO blockers,cinnamyl 3,4-dihydroxy-[alpha]-cyanocinnamate(CDC)or nordihydroguiairetic acid(NDGA)were used to identify the role of endogenous 15-HETE on expression of KV1.5 channel in cultured rat pulmonary arterial smooth muscle cells(PASMCs)and PAs.Results(1)The expressions of KV1.5 channel protein and mRNA in PASMCs and PAs preteated with CDC or NDGA greatly increased than those of PASMCs under hypoxia group.(2)Exogenous 15-HETE added to PASMCs pretreated with CDC or NDGA greatly decreased the expression of KV1.5 than that of adding PASMCs pretreated with CDC or NDGA under hypoxia condition.Conclusion The down-regulation of KV1.5 channel expression caused by hypoxia is through endogenous 15-HETE.
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Hypoxic pulmonary hypertension(HPH) is a common disease featured by acute hypoxic pulmonary vasoconstriction(HPV) and chronic hypoxic pulmonary vascular remolding(HPVR) leading to the sustained increasing of pulmonary artery pressure.There are many mediators involved in the HPH but none can illustrate it successfully.Primary work has found 15-lipoxygenase(15-LO) and its catalyzed production 15-hydroxyeicosatetraenoic acid(15-HETE)(from arachidonic acid) are up-regulated in pulmonary vascular when exprosed to hypoxia.And it has been found 15-LO/15-HETE involved in many processes of both the HPV and HPVR,indicating 15-LO/15-HETE may be an important mediator of HPH.Advances research on 15-LO/15-HETE may illustrate the mechanism of HPH,and will give some message in looking for a potential clinical target of HPH.
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Aim To investigate the effect of SA on induction of ERK1/2 activity in rat pulmonary smooth muscle cells(PASMCs).Methods Western blot analysis was employed to identify the activation of ERK1/2 stimulated by SA at different time points and concentrations in cultured rat PASMCs.Results An unexpected observation showed that ERK1/2 phosphorylation was seen after treatment of SA for 2h at a high concentration(30 ?mol?L-1) but not at lower concentration(from 1 nmol?L-1 to 1 ?mol?L-1).Activation of ERK1/2 pathway could be inhibited by an ERK1/2 inhibitor PD98059 or a protein kinase A(PKA) activator isoproterenol.Conclusion Together,these results suggest that SA has a strong dual regulating effect upon ERK1/2 through PKC and/or PKA pathways in rat PASMCs.
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Aim The purpose of this study was to compare the effect of AA、15-HETE、15-KETE and 8(S),15(S)-DiHETE on hypoxic and normoxic rabbit pulmonary arterial rings and to discuss their roles in the formation of PA hypertension.Methods Twelve neonatal rabbits were randomly divided into two groups(n=6):the normoxic group breathing fresh gas(FiO_2 =21%) and the hypoxic group breathing hypoxic gas(FiO_2=10%).After 9 days,they were anesthetized with pentobarbital sodium,and the chest was opened for removal of the heart and lungs en bloc,then PA rings(0.5~1.5 mm in diameter and 3 mm length) were prepared.We used tension studies of PA rings to observe the effect of AA、15-HETE、15-KETE and 8(S),15(S)-DiHETE on hypoxic and normoxic rabbit pulmonary arterial rings.Results ① AA、15-HETE、15-KETE and 8(S),15(S)-DiHETE constricted normoxic rabbit PA rings in a dose-dependent manner,respectively.Constriction of normoxic rabbit PA rings induced by 15-KETE、8(S),15(S)-DiHETE was significant,but that of AA、15-HETE wasn′t significant.② AA、15-HETE、15-KETE and 8(S),15(S)-DiHETE increased hypoxic rabbit PA rings' tension.Constriction of AA、15-HETE on rabbit PA rings in hypoxic group was significantly greater than that of normoxic group(P0.05).③ Constriction of 15-KETE on rabbit PA rings in normoxic group was significantly greater than that of hypoxia group(P