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
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
Acute pancreatitis is an inflammation of the pancreas that may lead to systemic inflammatory response syndrome and death due to multiple organ failure. Acinar cells, together with leukocytes, trigger the inflammatory ...Acute pancreatitis is an inflammation of the pancreas that may lead to systemic inflammatory response syndrome and death due to multiple organ failure. Acinar cells, together with leukocytes, trigger the inflammatory cascade in response to local damage of the pancreas. Amplification of the inflammatory cascade requires up-regulation of proinflammatory cytokines and this process is mediated not only by nuclear factor κB but also by chromatinmodifying complexes and chromatin remodeling. Among the different families of histone acetyltransferases, the p300/CBP family seems to be particularly associated with the inflammatory process. cAMP activates gene expression via the cAMP-responsive element (CRE) and the transcription factor CRE-binding protein (CREB). CREB can be phosphorylated and activated by different kinases, such as protein kinase A and MAPK, and then it recruits the histone acetyltransferase co-activator CREB-binding protein (CBP) and its homologue p300. The recruitment of CBP/p300 and changes in the level of histone acetylation are required for transcription activation. Transcriptional repression is also a dynamic and essential mechanism of down-regulation of genes for resolution of inflammation, which seems to be mediated mainly by protein phosphatases (PP1, PP2A and MKP1) and histone deacetylases(HDACs) .Class HDACs are key transcriptional regulators whose activities are controlled via phosphorylationdependent nucleo/cytoplasmic shuttling. PP2A is responsible for dephosphorylation of class HDACs, triggeringnuclear localization and repression of target genes, whereas phosphorylation triggers cytoplasmic localization leading to activation of target genes. The potential benefit from treatment with phosphodiesterase inhibitors and histone deacetylase inhibitors is discussed.展开更多
A thorough understanding of the genetic basis of rice grain traits is critical for the improvement of rice （Oryza sativa L.） varieties. In this study, we generated an F2 population by crossing the large-grain japoni...A thorough understanding of the genetic basis of rice grain traits is critical for the improvement of rice （Oryza sativa L.） varieties. In this study, we generated an F2 population by crossing the large-grain japonica cultivar CW23 with Peiai 64 （PA64）, an elite indica small-grain cultivar. Using QTL analysis, 17 QTLs for five grain traits were detected on four different chromosomes. Eight of the QTLs were newly-identified in this study. In particular, qGL3-1, a newly-identified grain length QTL with the highest LOD value and largest phenotypic variation, was fine-mapped to the 17 kb region of chromosome 3. A serine/threonine protein phosphatase gene encoding a repeat domain containing two Kelch motifs was identified as the unique candidate gene corresponding to this QTL. A comparison of PA64 and CW23 sequences revealed a single nucleotide substitution （C→A） at position 1092 in exon 10, resulting in replacement of Asp （D） in PA64 with Glu （E） in CW23 for the 364th amino acid. This variation is located at the D position of the conserved sequence motif AVLDT of the Kelch repeat. Genetic analysis of a near-isogenic line （NIL） for qGL3-1 revealed that the allele qGL3-1 from CW23 has an additive or partly dominant effect, and is suitable for use in molecular marker-assisted selection.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
Background:Metformin has pleiotropic effects beyond glucose reduction,including tumor inhibition and immune regulation.It enhanced the anti-tumor effects of programmed cell death protein 1(PD-1)inhibitors in serine/th...Background:Metformin has pleiotropic effects beyond glucose reduction,including tumor inhibition and immune regulation.It enhanced the anti-tumor effects of programmed cell death protein 1(PD-1)inhibitors in serine/threonine kinase 11(STK11)mutant non-small cell lung cancer(NSCLC)through an axis inhibition protein 1(AXIN1)-dependent manner.However,the alterations of tumor metabolism and metabolites upon metformin administration remain unclear.Methods:We performed untargeted metabolomics using liquid chromatography(LC)-mass spectrometry(MS)/MS system and conducted cell experiments to verify the results of bioinformatics analysis.Results:According to the Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway database,most metabolites were annotated into metabolism,including nucleotide metabolism.Next,the differentially expressed metabolites in H460(refers to H460 cells),H460_met(refers to metformin-treated H460 cells),and H460_KO_met(refers to metformin-treated Axin1-/-H460 cells)were distributed into six clusters based on expression patterns.The clusters with a reversed expression pattern upon metformin treatment were selected for further analysis.We screened out metabolic pathways through KEGG pathway enrichment analysis and found that multiple nucleotide metabolites enriched in this pathway were upregulated.Furthermore,these metabolites enhanced the cytotoxicity of activated T cells on H460 cells in vitro and can activate the stimulator of the interferon genes(STING)pathway independently of AXIN1.Conclusion:Relying on AXIN1,metformin upregulated multiple nucleotide metabolites which promoted STING signaling and the killing of activated T cells in STK11 mutant NSCLC,indicating a potential immunotherapeutic strategy for STK11 mutant NSCLC.展开更多
NF-kappaB plays a critical role in cell survival,apoptosis,and inflammatory responses.Serine/threoninespecific phosphatases(PPs)represent the second major class of enzymes that catalyze the dephosphorylation of protei...NF-kappaB plays a critical role in cell survival,apoptosis,and inflammatory responses.Serine/threoninespecific phosphatases(PPs)represent the second major class of enzymes that catalyze the dephosphorylation of proteins.The roles of PPs regulating NF-kappaB activities are poorly understood.Here we describe an RNAi-based screen to identify the PPs that involve in regulating NFkappaB signaling.Thirty-four candidate PPs siRNAs were synthesized and primarily screened by NF-kappaB reporter gene assay in HeLa cells.PHLPP,one of the protein phosphatase type 2C family members(PP2C),was identified as a positive regulator of NF-kappaB signaling.Knock-down of PHLPP dramatically attenuated TNFα-stimulated NF-kappaB transcriptional activation.Knockdown of PHLPP led to enhancement of NF-kappaB/p65 nuclear import and retention,but decreased TNFα-induced phosphorylation at Ser276 on p65.This critical phosphorylation was also drastically reduced by knock-down of PKCalpha and Akt1,two important serine/threonine kinases dephosphorylated by PHLPP.The results together suggest that PHLPP-Akt-PKC may represent an important signaling loop that activates NF-kappaB/p65 signaling through critical serine phosphorylation.展开更多
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 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 Grants SAF2006-06963, SAF2009-09500 and Consolider CSD-2007-00020 to Sastre J BFU2007-63120 and CSD2006-49 to López-Rodas G
文摘Acute pancreatitis is an inflammation of the pancreas that may lead to systemic inflammatory response syndrome and death due to multiple organ failure. Acinar cells, together with leukocytes, trigger the inflammatory cascade in response to local damage of the pancreas. Amplification of the inflammatory cascade requires up-regulation of proinflammatory cytokines and this process is mediated not only by nuclear factor κB but also by chromatinmodifying complexes and chromatin remodeling. Among the different families of histone acetyltransferases, the p300/CBP family seems to be particularly associated with the inflammatory process. cAMP activates gene expression via the cAMP-responsive element (CRE) and the transcription factor CRE-binding protein (CREB). CREB can be phosphorylated and activated by different kinases, such as protein kinase A and MAPK, and then it recruits the histone acetyltransferase co-activator CREB-binding protein (CBP) and its homologue p300. The recruitment of CBP/p300 and changes in the level of histone acetylation are required for transcription activation. Transcriptional repression is also a dynamic and essential mechanism of down-regulation of genes for resolution of inflammation, which seems to be mediated mainly by protein phosphatases (PP1, PP2A and MKP1) and histone deacetylases(HDACs) .Class HDACs are key transcriptional regulators whose activities are controlled via phosphorylationdependent nucleo/cytoplasmic shuttling. PP2A is responsible for dephosphorylation of class HDACs, triggeringnuclear localization and repression of target genes, whereas phosphorylation triggers cytoplasmic localization leading to activation of target genes. The potential benefit from treatment with phosphodiesterase inhibitors and histone deacetylase inhibitors is discussed.
基金supported by grants from the Geneti-cally Modified Organisms Breeding Major Projects of China(2011ZX08001-004-009)the National Natural Science Foun-dation of China(30900881)+2 种基金the Jiangxi Province Major Science and Technology Projects and Super Hybrid Rice BreedingDemonstration and Dissemination Projects(20114ABF03105)the Natural Science Foundation of Shandong Province(Y2006D22)
文摘A thorough understanding of the genetic basis of rice grain traits is critical for the improvement of rice （Oryza sativa L.） varieties. In this study, we generated an F2 population by crossing the large-grain japonica cultivar CW23 with Peiai 64 （PA64）, an elite indica small-grain cultivar. Using QTL analysis, 17 QTLs for five grain traits were detected on four different chromosomes. Eight of the QTLs were newly-identified in this study. In particular, qGL3-1, a newly-identified grain length QTL with the highest LOD value and largest phenotypic variation, was fine-mapped to the 17 kb region of chromosome 3. A serine/threonine protein phosphatase gene encoding a repeat domain containing two Kelch motifs was identified as the unique candidate gene corresponding to this QTL. A comparison of PA64 and CW23 sequences revealed a single nucleotide substitution （C→A） at position 1092 in exon 10, resulting in replacement of Asp （D） in PA64 with Glu （E） in CW23 for the 364th amino acid. This variation is located at the D position of the conserved sequence motif AVLDT of the Kelch repeat. Genetic analysis of a near-isogenic line （NIL） for qGL3-1 revealed that the allele qGL3-1 from CW23 has an additive or partly dominant effect, and is suitable for use in molecular marker-assisted selection.
基金People’s Hospital of Xuyong County-Southwest Medical University Science and Technology Strategic Cooperation Project(2023XYXNYD05)Guangdong Association of Clinical Trials(GACT)/Chinese Thoracic Oncology Group(CTONG)and Guangdong Provincial Key Lab of Translational Medicine in Lung Cancer(2017B030314120)Natural Science Foundation of Chongqing Municipality(CSTB2023NSCQ-MSX0554).
文摘Background:Metformin has pleiotropic effects beyond glucose reduction,including tumor inhibition and immune regulation.It enhanced the anti-tumor effects of programmed cell death protein 1(PD-1)inhibitors in serine/threonine kinase 11(STK11)mutant non-small cell lung cancer(NSCLC)through an axis inhibition protein 1(AXIN1)-dependent manner.However,the alterations of tumor metabolism and metabolites upon metformin administration remain unclear.Methods:We performed untargeted metabolomics using liquid chromatography(LC)-mass spectrometry(MS)/MS system and conducted cell experiments to verify the results of bioinformatics analysis.Results:According to the Kyoto Encyclopedia of Genes and Genomes(KEGG)pathway database,most metabolites were annotated into metabolism,including nucleotide metabolism.Next,the differentially expressed metabolites in H460(refers to H460 cells),H460_met(refers to metformin-treated H460 cells),and H460_KO_met(refers to metformin-treated Axin1-/-H460 cells)were distributed into six clusters based on expression patterns.The clusters with a reversed expression pattern upon metformin treatment were selected for further analysis.We screened out metabolic pathways through KEGG pathway enrichment analysis and found that multiple nucleotide metabolites enriched in this pathway were upregulated.Furthermore,these metabolites enhanced the cytotoxicity of activated T cells on H460 cells in vitro and can activate the stimulator of the interferon genes(STING)pathway independently of AXIN1.Conclusion:Relying on AXIN1,metformin upregulated multiple nucleotide metabolites which promoted STING signaling and the killing of activated T cells in STK11 mutant NSCLC,indicating a potential immunotherapeutic strategy for STK11 mutant NSCLC.
基金This research was supported by the National High Technology Research and Development Program of China(863 Program)(No.2006AA02Z191),the Bureau of Science and Technology of Guangzhou,China(No.2007Z1-E4041)Guangzhou Economic&Technological Development District(GETDD S&T Project)(2007G-P029).
文摘NF-kappaB plays a critical role in cell survival,apoptosis,and inflammatory responses.Serine/threoninespecific phosphatases(PPs)represent the second major class of enzymes that catalyze the dephosphorylation of proteins.The roles of PPs regulating NF-kappaB activities are poorly understood.Here we describe an RNAi-based screen to identify the PPs that involve in regulating NFkappaB signaling.Thirty-four candidate PPs siRNAs were synthesized and primarily screened by NF-kappaB reporter gene assay in HeLa cells.PHLPP,one of the protein phosphatase type 2C family members(PP2C),was identified as a positive regulator of NF-kappaB signaling.Knock-down of PHLPP dramatically attenuated TNFα-stimulated NF-kappaB transcriptional activation.Knockdown of PHLPP led to enhancement of NF-kappaB/p65 nuclear import and retention,but decreased TNFα-induced phosphorylation at Ser276 on p65.This critical phosphorylation was also drastically reduced by knock-down of PKCalpha and Akt1,two important serine/threonine kinases dephosphorylated by PHLPP.The results together suggest that PHLPP-Akt-PKC may represent an important signaling loop that activates NF-kappaB/p65 signaling through critical serine phosphorylation.
