The signaling mechanisms underlying ischemia-induced nerve cell apoptosis are poorly understood. We investigated the effects of apoptosis-related signal transduction pathways following ischemic spinal cord injury, inc...The signaling mechanisms underlying ischemia-induced nerve cell apoptosis are poorly understood. We investigated the effects of apoptosis-related signal transduction pathways following ischemic spinal cord injury, including extracellular signal-regulated kinase（ERK）, serine-threonine protein kinase（Akt） and c-Jun N-terminal kinase（JNK） signaling pathways. We established a rat model of acute spinal cord injury by inserting a catheter balloon in the left subclavian artery for 25 minutes. Rat models exhibited notable hindlimb dysfunction. Apoptotic cells were abundant in the anterior horn and central canal of the spinal cord. The number of apoptotic neurons was highest 48 hours post injury. The expression of phosphorylated Akt（pAkt） and phosphorylated ERK（p-ERK） increased immediately after reperfusion, peaked at 4 hours（p-Akt） or 2 hours（p-ERK）, decreased at 12 hours, and then increased at 24 hours. Phosphorylated JNK expression reduced after reperfusion, increased at 12 hours to near normal levels, and then showed a downward trend at 24 hours. Pearson linear correlation analysis also demonstrated that the number of apoptotic cells negatively correlated with p-Akt expression. These findings suggest that activation of Akt may be a key contributing factor in the delay of neuronal apoptosis after spinal cord ischemia, particularly at the stage of reperfusion, and thus may be a target for neuronal protection and reduction of neuronal apoptosis after spinal cord injury.展开更多
The effects of tacrolimus postconditioning on protein-serine-threonine kinases （Akt） phos- phorylation and apoptotic cell death in rats after spinal cord ischemia-reperfusion injury were investi- gated. Ninety male ...The effects of tacrolimus postconditioning on protein-serine-threonine kinases （Akt） phos- phorylation and apoptotic cell death in rats after spinal cord ischemia-reperfusion injury were investi- gated. Ninety male SD rats were randomly divided into sham operation group, ischemia-reperfusion group and tacrolimus postconditioning group. The model of spinal cord ischemia was established by means of catheterization through femoral artery and balloon dilatation. The spinal cord was reperfused 20 min after ischemia via removing saline out of balloon. The corresponding spinal cord segments were excised and determined for Akt activity in spinal cord tissue by using Western blotting at 5, 15, and 60 min after reperfusion respectively. Spinal cord tissue sections were stained immunohistochemically for detection of the phosphorylated Akt expression at 15 min after reperfusion. Flow cytometry was applied to assess apoptosis of neural cells, and dry-wet weights method was employed to measure water content in spinal cord tissue at 24 h after reperfusion. The results showed that the activities of Akt in tarcolimus postconditioning group were significantly higher than those in ischemia-reperfusion group at 5, 15, and 60 min after reperfusion （P〈0.05, P〈0.01）. The Akt activities reached the peak at 15 min after reperfu- sion in ischemia-reperfusion group and tacrolimus postconditioning group. The percentage of apoptotic cells and water content in spinal cord tissue were significantly reduced （P〈0.01） in tacrolimus postcon- ditioning group as compared with those in ischemia-reperfusion group at 24 h after reperfusion. It is concluded that tacrolimus postconditioning can increase Akt activity in spinal cord tissue of rats, inhibit apoptosis of neural cells as well as tissue edema, and thereby alleviate spinal cord ischemia-reperfusion injury.展开更多
Pim-3 is a member of the provirus integration site for Moloney murine leukemia virus(Pim)family proteins that exhibit serine/threonine kinase activity.Similar to the other Pim kinases(Pim-1 and Pim-2),Pim-3 is involve...Pim-3 is a member of the provirus integration site for Moloney murine leukemia virus(Pim)family proteins that exhibit serine/threonine kinase activity.Similar to the other Pim kinases(Pim-1 and Pim-2),Pim-3 is involved in many cellular processes,including cell proliferation,survival,and protein synthesis.Although Pim-3is expressed in normal vital organs,it is overexpressed particularly in tumor tissues of endoderm-derived organs,including the liver,pancreas,and colon.Silencing of Pim-3 expression can retard in vitro cell proliferation of hepatocellular,pancreatic,and colon carcinoma cell lines by promoting cell apoptosis.Pim-3 lacks the regulatory domains similarly as Pim-1 and Pim-2 lack,and therefore,Pim-3 can exhibit its kinase activity once it is expressed.Pim-3 expression is regulated at transcriptional and post-transcriptional levels by transcription factors(e.g.,Ets-1)and post-translational modifiers(e.g.,translationally-controlled tumor protein),respectively.Pim-3 could promote growth and angiogenesis of human pancreatic cancer cells in vivo in an orthotopic nude mouse model.Furthermore,a Pim-3 kinase inhibitor inhibited cell proliferation when human pancreatic cancer cells were injected into nude mice,without inducing any major adverse effects.Thus,Pim-3 kinase may serve as a novel molecular target for developing targeting drugs against pancreatic and other types of cancer.展开更多
目的探究脂肪含量和肥胖相关蛋白(fat mass and obesity-associated protein,FTO)和丝氨酸-苏氨酸激酶蛋白激酶D2(serine-threonine kinase protein kinase D2,PRKD2)在糖尿病肾病(diabetic kidney disease,DKD)进展中的调控作用和调节...目的探究脂肪含量和肥胖相关蛋白(fat mass and obesity-associated protein,FTO)和丝氨酸-苏氨酸激酶蛋白激酶D2(serine-threonine kinase protein kinase D2,PRKD2)在糖尿病肾病(diabetic kidney disease,DKD)进展中的调控作用和调节机制。方法采用35 mmol/L葡萄糖对足细胞(MPC5细胞)进行高糖刺激24h构建DKD体外模型。采用FTO过表达载体(pcDNA-FTO)和PRKD2过表达载体(pcDNA-PRKD2),或空载体(vector)转染高糖诱导的MPC5细胞。通过RT-qPCR检测FTO和PRKD2过表达效率;MeRIP检测PRKD2 mRNA的N6-甲基腺苷(N6-methyladenosine,m6A)修饰水平;ELISA检测Caspase-3活性、IL-6,TNF-α和单核细胞趋化蛋白-1(monocyte chemotactic protein-1,MCP-1)分泌量;流式细胞术分析细胞凋亡率;Western blot评估FTO和PRKD2蛋白水平,以及SIRT1/HIF-1α通路关键蛋白表达水平;Pearson分析FTO和PRKD2水平的相关性。结果与无高糖诱导对照组比较,高糖诱导的足细胞中FTO蛋白(0.51±0.04 vs 1.00±0.03)和PRKD2蛋白(0.45±0.03 vs 1.01±0.04)水平显著下调,差异具有统计学意义(t=13.17,16.76,均P<0.001)。高糖诱导的足细胞中FTO蛋白水平和PRKD2蛋白水平呈正相关(r2=0.7051,P<0.001)。与vector组相比,pcDNA-FTO组PRKD2 mRNA的m6A水平(0.56±0.09 vs1.01±0.13)降低,PRKD2 mRNA水平(3.16±0.14 vs 1.03±0.02)显著升高,差异具有统计学意义(t=51.37,11.82,均P<0.001)。与control组(IL-6:512.76±61.85 pg/ml,TNF-α:28.17±2.83 pg/ml,MCP-1:157.31±17.69 pg/ml)和vector组(IL-6:498.41±87.51 pg/ml,TNF-α:26.35±5.47 pg/ml,MCP-1:165.52±16.87 pg/ml)比较,pcDNA-PRKD2组IL-6(301.86±21.85 pg/ml),TNF-α(11.06±4.12 pg/ml),MCP-1分泌量(81.45±9.03pg/ml)显著减少,差异具有统计学意义(F=7.51,10.47,61.97,均P<0.01)。与control组(Caspase-3:689.65±79.5U/L,细胞凋亡率:22.31%±2.69%)和vector组(Caspase-3:715.91±113.58 U/L,细胞凋亡率:21.07%±3.28%)比较,pcDNA-PRKD2组Caspase-3活性(437.64±104.76 U/L)和细胞凋亡率(8.41%±3.15%)下降,差异具有统计学意义(F=2.35,79.13,均P<0.01)。与control组(SIRT1:1.01±0.05,HIF-1α:1.03±0.07)和vector组(SIRT1:0.97±0.05,HIF-1α:1.02±0.03)相比,pcDNA-PRKD2组SIRT1蛋白(3.51±0.15)水平升高,HIF-1α蛋白(0.37±0.07)水平降低,差异具有统计学意义(F=31.54,8.31,均P<0.01)。结论FTO介导m6A修饰的PRKD2通过SIRT1/HIF-1α通路抑制高糖诱导的足细胞炎症反应和细胞凋亡。展开更多
基金supported by the National Natural Science Foundation of ChinaNo.81271387+3 种基金the Research Special Fund of Public Welfare and Health Department of ChinaNo.201402009the National Key Technology R&D Program in ChinaNo.Z141107002514031
文摘The signaling mechanisms underlying ischemia-induced nerve cell apoptosis are poorly understood. We investigated the effects of apoptosis-related signal transduction pathways following ischemic spinal cord injury, including extracellular signal-regulated kinase（ERK）, serine-threonine protein kinase（Akt） and c-Jun N-terminal kinase（JNK） signaling pathways. We established a rat model of acute spinal cord injury by inserting a catheter balloon in the left subclavian artery for 25 minutes. Rat models exhibited notable hindlimb dysfunction. Apoptotic cells were abundant in the anterior horn and central canal of the spinal cord. The number of apoptotic neurons was highest 48 hours post injury. The expression of phosphorylated Akt（pAkt） and phosphorylated ERK（p-ERK） increased immediately after reperfusion, peaked at 4 hours（p-Akt） or 2 hours（p-ERK）, decreased at 12 hours, and then increased at 24 hours. Phosphorylated JNK expression reduced after reperfusion, increased at 12 hours to near normal levels, and then showed a downward trend at 24 hours. Pearson linear correlation analysis also demonstrated that the number of apoptotic cells negatively correlated with p-Akt expression. These findings suggest that activation of Akt may be a key contributing factor in the delay of neuronal apoptosis after spinal cord ischemia, particularly at the stage of reperfusion, and thus may be a target for neuronal protection and reduction of neuronal apoptosis after spinal cord injury.
基金supported by the Hubei Provincial Natural Science Foundation of China(No.2012FFB04406)
文摘The effects of tacrolimus postconditioning on protein-serine-threonine kinases （Akt） phos- phorylation and apoptotic cell death in rats after spinal cord ischemia-reperfusion injury were investi- gated. Ninety male SD rats were randomly divided into sham operation group, ischemia-reperfusion group and tacrolimus postconditioning group. The model of spinal cord ischemia was established by means of catheterization through femoral artery and balloon dilatation. The spinal cord was reperfused 20 min after ischemia via removing saline out of balloon. The corresponding spinal cord segments were excised and determined for Akt activity in spinal cord tissue by using Western blotting at 5, 15, and 60 min after reperfusion respectively. Spinal cord tissue sections were stained immunohistochemically for detection of the phosphorylated Akt expression at 15 min after reperfusion. Flow cytometry was applied to assess apoptosis of neural cells, and dry-wet weights method was employed to measure water content in spinal cord tissue at 24 h after reperfusion. The results showed that the activities of Akt in tarcolimus postconditioning group were significantly higher than those in ischemia-reperfusion group at 5, 15, and 60 min after reperfusion （P〈0.05, P〈0.01）. The Akt activities reached the peak at 15 min after reperfu- sion in ischemia-reperfusion group and tacrolimus postconditioning group. The percentage of apoptotic cells and water content in spinal cord tissue were significantly reduced （P〈0.01） in tacrolimus postcon- ditioning group as compared with those in ischemia-reperfusion group at 24 h after reperfusion. It is concluded that tacrolimus postconditioning can increase Akt activity in spinal cord tissue of rats, inhibit apoptosis of neural cells as well as tissue edema, and thereby alleviate spinal cord ischemia-reperfusion injury.
基金Supported by the National Science Foundation of China(in part),No.30973476 and No.812727
文摘Pim-3 is a member of the provirus integration site for Moloney murine leukemia virus(Pim)family proteins that exhibit serine/threonine kinase activity.Similar to the other Pim kinases(Pim-1 and Pim-2),Pim-3 is involved in many cellular processes,including cell proliferation,survival,and protein synthesis.Although Pim-3is expressed in normal vital organs,it is overexpressed particularly in tumor tissues of endoderm-derived organs,including the liver,pancreas,and colon.Silencing of Pim-3 expression can retard in vitro cell proliferation of hepatocellular,pancreatic,and colon carcinoma cell lines by promoting cell apoptosis.Pim-3 lacks the regulatory domains similarly as Pim-1 and Pim-2 lack,and therefore,Pim-3 can exhibit its kinase activity once it is expressed.Pim-3 expression is regulated at transcriptional and post-transcriptional levels by transcription factors(e.g.,Ets-1)and post-translational modifiers(e.g.,translationally-controlled tumor protein),respectively.Pim-3 could promote growth and angiogenesis of human pancreatic cancer cells in vivo in an orthotopic nude mouse model.Furthermore,a Pim-3 kinase inhibitor inhibited cell proliferation when human pancreatic cancer cells were injected into nude mice,without inducing any major adverse effects.Thus,Pim-3 kinase may serve as a novel molecular target for developing targeting drugs against pancreatic and other types of cancer.
