Plant hormone abscisic acid （ABA） serves as an integrator of environmental stresses such as drought to trig-ger stomatal closure by regulating specific ion channels in guard cells. We previously reported that SLAC1,...Plant hormone abscisic acid （ABA） serves as an integrator of environmental stresses such as drought to trig-ger stomatal closure by regulating specific ion channels in guard cells. We previously reported that SLAC1, an outward anion channel required for stomatal closure, was regulated via reversible protein phosphorylation events involving ABA signaling components, including protein phosphatase 2C members and a SnRK2-type kinase （OST1）. In this study, we reconstituted the ABA signaling pathway as a protein-protein interaction relay from the PYL/RCAR-type receptors, to the PP2C-SnRK2 phosphatase-kinase pairs, to the ion channel SLAC1. The ABA receptors interacted with and inhibited PP2C phosphatase activity against the SnRK2-type kinase, releasing active SnRK2 kinase to phosphorylate, and activate the SLAC1 channel, leading to reduced guard cell turgor and stomatal closure. Both yeast two-hybrid and bimolecular fluorescence complementation assays were used to verify the interactions among the components in the pathway. These biochemical assays demonstrated activity modifications of phosphatases and kinases by their interaction partners. The SLAC1 channel activity was used as an endpoint readout for the strength of the signaling pathway, depending on the presence of different combinations of signaling components. Further study using transgenic plants overexpressing one of the ABA receptors demonstrated that changing the relative level of interacting partners would change ABA sensitivity.展开更多
目的观察磷脂酰肌醇-3激酶(PI3K)-蛋白质丝氨酸/苏氨酸激酶(AKt)-内皮型一氧化氮合酶(e NOS)信号转导通路在硫化氢(H2S)抑制内皮素-1(endothelin-1,ET-1)诱导心肌肥大过程中的作用。方法体外培养原代心肌细胞,将其随机分为6组,每组4孔,...目的观察磷脂酰肌醇-3激酶(PI3K)-蛋白质丝氨酸/苏氨酸激酶(AKt)-内皮型一氧化氮合酶(e NOS)信号转导通路在硫化氢(H2S)抑制内皮素-1(endothelin-1,ET-1)诱导心肌肥大过程中的作用。方法体外培养原代心肌细胞,将其随机分为6组,每组4孔,1对照组:加入等体积无血清的DMEM培养基;2肥大(ET-1)组:加入终浓度为10-8 mol/L的ET-1;剩余4组为实验组,各组分别加入不同终浓度的H2S供体-Na HS:310-15 M Na HS组:加入10-15 mol/L Na HS+10-8 mol/l ET-1;410-14 M Na HS组:加入10-14 mol/L Na HS+10-8 mol/L ET-1;510-13 M Na HS组:加入10-13 mol/L Na HS+10-8 mol/L ET-1;610-12 M Na HS组:加入10-12 mol/L Na HS+10-8 mol/L ET-1。上述各组药物分别刺激24 h后测定心肌细胞表面积、细胞总蛋白含量、培养液NO含量,RT-PCR检测心肌细胞心房利钠肽(atrial natriuretic peptide,ANP)、脑钠肽(B-type natriuretic peptide,BNP)、磷脂酰肌醇-3激酶(phosphatidylinositol-3-kinase,PI3K)、蛋白激酶B(protein kinase B,PKB/AKt)、e NOS m RNA水平,Western Blot技术检测总AKt和磷酸化AKt蛋白表达含量。结果肥大(ET-1)组的心肌细胞表面积(1933.80±143.06)和细胞总蛋白含量(367.51±25.9)均高于对照组(787.27±107.66,218.55±21.28,P<0.05),ANP及BNP m RNA的表达量也明显增加(P<0.05),但PI3K、AKt、e NOS m RNA表达水平,磷酸化AKt程度和NO的释放量(4.60±0.73)低于对照组(8.63±0.30,P<0.05),各实验组给予不同浓度Na HS刺激后能够浓度依赖性的抑制这种肥大效应(P<0.05),同时上调了PI3K/AKt/e NOS通路各信号分子的表达量(P<0.05)。结论 H2S对ET-1诱导的心肌肥大有一定的抑制作用,这种作用可能与激活PI3K-AKt-e NOS信号通路有关。展开更多
目的:探讨蛋白激酶C(PKC)在兔内毒素休克诱发急性肾损伤中的作用及其可能作用机制。方法:健康清洁级雄性新西兰大白兔40只,采取随机数字表法分为对照组(CON组)、内毒素休克致急性肾损伤组(AKI组)、PKC-α阻断剂-白屈菜赤碱加AKI组(CHA)...目的:探讨蛋白激酶C(PKC)在兔内毒素休克诱发急性肾损伤中的作用及其可能作用机制。方法:健康清洁级雄性新西兰大白兔40只,采取随机数字表法分为对照组(CON组)、内毒素休克致急性肾损伤组(AKI组)、PKC-α阻断剂-白屈菜赤碱加AKI组(CHA)、PKC-α激活剂-佛波酯加AKI组(PMA)。PMA组经兔耳缘静脉注射佛波酯5μg/kg,CHA组静脉注射白屈菜赤碱5 mg/kg,CON组与AKI组注射各自溶媒1%DMSO 0.5 m L。30 min后,AKI组、PMA组及CHA组静脉注射脂多糖(LPS)5 mg/kg(溶于2 m L生理盐水),CON组给予等容量生理盐水。静脉注射LPS或生理盐水6 h时,采集动脉血,检测血清尿素氮(BUN)和肌酐(Cr)浓度,处死动物后取肾组织,进行病理学观察及肾损伤评分,测定肾组织PKC-α蛋白、HO-1蛋白、Nrf2核蛋白及总蛋白的表达水平。结果:与CON组比较,AKI组、CHA组及PMA组血清BUN、Cr浓度升高,肾组织病理学评分升高,PKC-α蛋白(1.37±0.26)、HO-1蛋白(0.89±0.11)、Nrf2核蛋白(0.97±0.26)及总蛋白的表达均上调(P<0.05);与AKI组比较,PMA组血清BUN、Cr浓度降低,肾组织病理学评分降低,PKC-α蛋白、HO-1蛋白、Nrf2核蛋白及总蛋白的表达均上调(P<0.05),CHA组血清BUN、Cr浓度升高,肾组织病理学评分(9.8±3.9)升高,PKC-α蛋白、HO-1蛋白、Nrf2核蛋白及总蛋白的表达均下调(P<0.05)。结论:PKC-α激活是内毒素休克诱发急性肾损伤时机体的适应性调节反应机制之一,其机制可能与激活Nrf2/ARE通路、上调HO-1的表达有关。展开更多
Background Exposure to cigarette smoke stimulates the proliferation of human pulmonary artery smooth muscle cells （HPASMCs） in vivo and in vitro. However, the molecular mechanism remains unclear. This study aimed at...Background Exposure to cigarette smoke stimulates the proliferation of human pulmonary artery smooth muscle cells （HPASMCs） in vivo and in vitro. However, the molecular mechanism remains unclear. This study aimed at investigating the role of signaling pathways involving protein kinase C alpha （PKCα） and cyclin D1 in the cigarette smoke extract （CSE）-induced HPASMCs proliferation.Methods Synchronized HPASMCs were treated with different concentrations of CSE. Cell proliferation was evaluated by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyttetrazolium bromide （MTT） assay and cell counting. Cell cycle was analyzed by flow cytometry with propidium iodide staining. Activation of PKCα was measured by detecting the expression of PKCαprotein in the cytosolic and membrane fractions using Western blotting analysis. Small interfering RNA （siRNA） was used to knockdown PKCα and cyclin D1. The cyclin D1 mRNA was assessed by real-time RT-PCR. The PKCα and cyclin D1protein levels were detected by Western blotting.Results Low concentrations of CSE （1%-10%） stimulated proliferation of HPASMCs, with its maximal effect at 5%.CSE （5%） led to PKCα activation. Inhibition of PKCα activity using G（o） 6976 or siRNA-mediated knockdown of PKCα significantly attenuated CSE-induced cell proliferation and G1/S transition. Cyclin D1, one of key regulators of G1/S transition, was found to be upregulated by 5% CSE at both the mRNA and protein levels. CSE-stimulated cellproliferation and G1/S transition was abolished by cyclin D1 siRNA. Moreover, G（o） 6976 or PKCα siRNA significantlysuppressed CSE-induced upregulation of cyclin D1 at both the mRNA and protein levels.Conclusion PKCα-cyclin D1 pathway at least partially mediates the CSE-induced proliferation in HPASMCs.展开更多
基金a grant from the Biogreen21 Program (PJ008222) Rural Development Administration and the Research Foundation of Korea (NFR) grant funded by the Korea government (No.2011-0007600)，the US National Science Foundation and Korean WCU Program of National Research Foundation (to S.L.).No conflict of interest declared
文摘Plant hormone abscisic acid （ABA） serves as an integrator of environmental stresses such as drought to trig-ger stomatal closure by regulating specific ion channels in guard cells. We previously reported that SLAC1, an outward anion channel required for stomatal closure, was regulated via reversible protein phosphorylation events involving ABA signaling components, including protein phosphatase 2C members and a SnRK2-type kinase （OST1）. In this study, we reconstituted the ABA signaling pathway as a protein-protein interaction relay from the PYL/RCAR-type receptors, to the PP2C-SnRK2 phosphatase-kinase pairs, to the ion channel SLAC1. The ABA receptors interacted with and inhibited PP2C phosphatase activity against the SnRK2-type kinase, releasing active SnRK2 kinase to phosphorylate, and activate the SLAC1 channel, leading to reduced guard cell turgor and stomatal closure. Both yeast two-hybrid and bimolecular fluorescence complementation assays were used to verify the interactions among the components in the pathway. These biochemical assays demonstrated activity modifications of phosphatases and kinases by their interaction partners. The SLAC1 channel activity was used as an endpoint readout for the strength of the signaling pathway, depending on the presence of different combinations of signaling components. Further study using transgenic plants overexpressing one of the ABA receptors demonstrated that changing the relative level of interacting partners would change ABA sensitivity.
文摘目的观察磷脂酰肌醇-3激酶(PI3K)-蛋白质丝氨酸/苏氨酸激酶(AKt)-内皮型一氧化氮合酶(e NOS)信号转导通路在硫化氢(H2S)抑制内皮素-1(endothelin-1,ET-1)诱导心肌肥大过程中的作用。方法体外培养原代心肌细胞,将其随机分为6组,每组4孔,1对照组:加入等体积无血清的DMEM培养基;2肥大(ET-1)组:加入终浓度为10-8 mol/L的ET-1;剩余4组为实验组,各组分别加入不同终浓度的H2S供体-Na HS:310-15 M Na HS组:加入10-15 mol/L Na HS+10-8 mol/l ET-1;410-14 M Na HS组:加入10-14 mol/L Na HS+10-8 mol/L ET-1;510-13 M Na HS组:加入10-13 mol/L Na HS+10-8 mol/L ET-1;610-12 M Na HS组:加入10-12 mol/L Na HS+10-8 mol/L ET-1。上述各组药物分别刺激24 h后测定心肌细胞表面积、细胞总蛋白含量、培养液NO含量,RT-PCR检测心肌细胞心房利钠肽(atrial natriuretic peptide,ANP)、脑钠肽(B-type natriuretic peptide,BNP)、磷脂酰肌醇-3激酶(phosphatidylinositol-3-kinase,PI3K)、蛋白激酶B(protein kinase B,PKB/AKt)、e NOS m RNA水平,Western Blot技术检测总AKt和磷酸化AKt蛋白表达含量。结果肥大(ET-1)组的心肌细胞表面积(1933.80±143.06)和细胞总蛋白含量(367.51±25.9)均高于对照组(787.27±107.66,218.55±21.28,P<0.05),ANP及BNP m RNA的表达量也明显增加(P<0.05),但PI3K、AKt、e NOS m RNA表达水平,磷酸化AKt程度和NO的释放量(4.60±0.73)低于对照组(8.63±0.30,P<0.05),各实验组给予不同浓度Na HS刺激后能够浓度依赖性的抑制这种肥大效应(P<0.05),同时上调了PI3K/AKt/e NOS通路各信号分子的表达量(P<0.05)。结论 H2S对ET-1诱导的心肌肥大有一定的抑制作用,这种作用可能与激活PI3K-AKt-e NOS信号通路有关。
文摘目的:探讨蛋白激酶C(PKC)在兔内毒素休克诱发急性肾损伤中的作用及其可能作用机制。方法:健康清洁级雄性新西兰大白兔40只,采取随机数字表法分为对照组(CON组)、内毒素休克致急性肾损伤组(AKI组)、PKC-α阻断剂-白屈菜赤碱加AKI组(CHA)、PKC-α激活剂-佛波酯加AKI组(PMA)。PMA组经兔耳缘静脉注射佛波酯5μg/kg,CHA组静脉注射白屈菜赤碱5 mg/kg,CON组与AKI组注射各自溶媒1%DMSO 0.5 m L。30 min后,AKI组、PMA组及CHA组静脉注射脂多糖(LPS)5 mg/kg(溶于2 m L生理盐水),CON组给予等容量生理盐水。静脉注射LPS或生理盐水6 h时,采集动脉血,检测血清尿素氮(BUN)和肌酐(Cr)浓度,处死动物后取肾组织,进行病理学观察及肾损伤评分,测定肾组织PKC-α蛋白、HO-1蛋白、Nrf2核蛋白及总蛋白的表达水平。结果:与CON组比较,AKI组、CHA组及PMA组血清BUN、Cr浓度升高,肾组织病理学评分升高,PKC-α蛋白(1.37±0.26)、HO-1蛋白(0.89±0.11)、Nrf2核蛋白(0.97±0.26)及总蛋白的表达均上调(P<0.05);与AKI组比较,PMA组血清BUN、Cr浓度降低,肾组织病理学评分降低,PKC-α蛋白、HO-1蛋白、Nrf2核蛋白及总蛋白的表达均上调(P<0.05),CHA组血清BUN、Cr浓度升高,肾组织病理学评分(9.8±3.9)升高,PKC-α蛋白、HO-1蛋白、Nrf2核蛋白及总蛋白的表达均下调(P<0.05)。结论:PKC-α激活是内毒素休克诱发急性肾损伤时机体的适应性调节反应机制之一,其机制可能与激活Nrf2/ARE通路、上调HO-1的表达有关。
基金This work was supported by a grant from National Natural Science Foundation of China （No. 30871128）.
文摘Background Exposure to cigarette smoke stimulates the proliferation of human pulmonary artery smooth muscle cells （HPASMCs） in vivo and in vitro. However, the molecular mechanism remains unclear. This study aimed at investigating the role of signaling pathways involving protein kinase C alpha （PKCα） and cyclin D1 in the cigarette smoke extract （CSE）-induced HPASMCs proliferation.Methods Synchronized HPASMCs were treated with different concentrations of CSE. Cell proliferation was evaluated by 3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyttetrazolium bromide （MTT） assay and cell counting. Cell cycle was analyzed by flow cytometry with propidium iodide staining. Activation of PKCα was measured by detecting the expression of PKCαprotein in the cytosolic and membrane fractions using Western blotting analysis. Small interfering RNA （siRNA） was used to knockdown PKCα and cyclin D1. The cyclin D1 mRNA was assessed by real-time RT-PCR. The PKCα and cyclin D1protein levels were detected by Western blotting.Results Low concentrations of CSE （1%-10%） stimulated proliferation of HPASMCs, with its maximal effect at 5%.CSE （5%） led to PKCα activation. Inhibition of PKCα activity using G（o） 6976 or siRNA-mediated knockdown of PKCα significantly attenuated CSE-induced cell proliferation and G1/S transition. Cyclin D1, one of key regulators of G1/S transition, was found to be upregulated by 5% CSE at both the mRNA and protein levels. CSE-stimulated cellproliferation and G1/S transition was abolished by cyclin D1 siRNA. Moreover, G（o） 6976 or PKCα siRNA significantlysuppressed CSE-induced upregulation of cyclin D1 at both the mRNA and protein levels.Conclusion PKCα-cyclin D1 pathway at least partially mediates the CSE-induced proliferation in HPASMCs.
