Electro-acupuncture for STAT3 expression and nuclear translocation in hippocampal tissues of rats following cerebral ischemia/reperfusion

BACKGROUND: It has been found in recent years that STAT3 widely distributes in nervous system, including hippocampal CA1-3 region, dentate gyrus and cerebral neocortex, etc. Ischemic brain injury can cause the release of some cytokines and growth factors, while electro-acupuncture may have multi-level, multi-channel and multi-target protective and interventional effects on ischemic brain injury. OBJECTIVE: To observe the effects of electro-acupuncture on STAT3 expression and nuclear translocation in hippocampal CA1 region of rat models of brain ischemia/reperfusion. DESIGN: Randomized and controlled observation. SETTING: Staff Room of Acupuncture and Moxibustion, Department of Acupuncture and Bone Injury, Hubei College of Traditional Chinese Medicine; Tongji Medical College, Huazhong University of Science and Technology. MATERIALS: Seventy-two healthy SD rats, of clean degree and either gender, weighing (200±20) g, were provided by the Experimental Animal Center of Hubei College of Traditional Chinese Medicine. STAT3 monoclonal antibody was purchased from Santa Cruz Company, USA, and G-6805 electro-acupuncture instrument was purchased from Shanghai Medical Electronic Instruments Factory. METHODS: This experiment was carried out in the comprehensive laboratory of Department of Acupuncture and Bone Injury, Hubei College of Traditional Chinese Medicine between September 2005 and February 2006. Seventy-two rats were randomly divided into 4 groups: ① control group(n =6): Untouched. ② Sham-operation group (n =18): Artery was isolated, but without inserting thread bolt.③ Model group (n =24): Rat models of local brain ischemia/reperfusion were established with modified suture occlusion. ④Electro-acupuncture group (n =24): Dazhui and bilateral Neiguan points were selected for electro-acupuncture treatment. No. 28 acupuncture needle of 3.33 cm was used in the treatment. A G-6085 electro-acupuncture instrument with continuous wave, frequency of 120 times/min, intensity of 1 mA, 30 min/time, was used. Acupuncture was conducted firstly at ischemia/reperfusion 3 hours, then once every 12 hours. STAT3 positive nuclear translocation in hippocampal CA1 region of rats was observed with immunohistochemical method at 24, 48 and 72 hours after brain ishcemia/reperfusion, and then STAT3 positive cells were counted. MAIN OUTCOME MEASURES: STAT3 positive cells and nuclear translocation in hippocampal CA1 region of rats in each group. RESULTS: All the 72 rats were involved in the result analysis. ①In the control group and sham-operation group, STAT3 positive cells with light cytoplasm and nucleus were decreased , and nuclear translocation was not found. ② In the model group, STAT3 positive cells were mostly found in the cytoplasm of the hippocampal CA1 region at the ischemic side of rats after ischemia/reperfusion 24 hours. They were significantly more than those in the sham-operation group and control group [(18.00±2.68), (9.00±1.35), (8.00±1.22) cells/ mm2, P < 0.01], but cells with nuclear reaction were fewer; At ischemia/reperfusion 48 and 72 hours, STAT3 positive cells were increased, and they were significantly more than those of sham-operation group [(25.00±3.23), (35.00±3.52) cells/mm2, (13.00±1.93), (12.00±1.24) cells/mm2, P < 0.01]. Positive cells with nuclear reaction were found dark-stained. ③At ischemia/reperfusion 24, 48 and 72 hours, STAT3 positive cells were strongly expressed in hippocampal CA1 region at ischemic side of rats of electro-acupuncture group, and they were significantly more than those of model group [(25±3.52), (50±6.31), (75±8.09) cells/mm2, P < 0.01]. STAT3 positive cells were gradually enhanced with time, and considerable STAT3 nuclear positive reaction cells were found. CONCLUSION: Electro-acupuncture can activate STAT3 protein expression in hippocampal tissue of rats with local brain ischemia/reperfusion, promote STAT3 nuclear translocation and function its neuroprotective effect.

Studies on Differential Nuclear Translocation Mechanism and Assembly of the Three Subunits of the Arabidopsis thaliana Transcription Factor NF-Y

The eukaryotic transcription factor NF-Y consists of three subunits （A, B, and C）, which are encoded in Ara- bidopsis thaliana in multigene families consisting of 10, 13, and 13 genes, respectively. In principle, all potential combi- nations of the subunits are possible for the assembly of the heterotrimeric complex. We aimed at assessing the probability of each subunit to participate in the assembly of NF-Y. The evaluation of physical interactions among all members of the NF-Y subunit families indicate a strong requirement for NF-YB/NF-YC heterodimerization before the entire complex can be accomplished. By means of a modified yeast two-hybrid system assembly of all three subunits to a heterotrimeric complex was demonstrated. Using GFP fusion constructs, NF-YA and NF-YC localization in the nucleus was demonstrated, while NF- YB is solely imported into the nucleus as a NF-YC-associated heterodimer NF-YC. This piggyback transport of the two Arabidopsis subunits differs from the import of the NF-Y heterotrimer of heterotrophic organisms. Based on a peptide structure model of the histone-fold-motifs, disulfide bonding among intramolecular conserved cysteine residues of NF-YB, which is responsible for the redox-regulated assembly of NF-YB and NF-YC in human and Aspergillus nidulans, can be excluded for Arabidopsis NF-YB.

Themis regulates metabolic signaling and effector functions in CD4^(+) T cells by controlling NFAT nuclear translocation

Themis is a T cell lineage-specific molecule that is involved in TCR signal transduction.The effects of germline Themis deletion on peripheral CD4^(+)T cell function have not been described before.In this study,we found that Themis-deficient CD4^(+)T cells had poor proliferative responses,reduced cytokine production in vitro and weaker inflammatory potential,as measured by their ability to cause colitis in vivo.Resting T cells are quiescent,whereas activated T cells have high metabolic demands.Fulfillment of these metabolic demands depends upon nutrient availability and upregulation of nutrient intake channels after efficient TCR signal transduction,which leads to metabolic reprogramming in T cells.We tested whether defects in effector functions were caused by impaired metabolic shifts in Themis-deficient CD4^(+)T cells due to inefficient TCR signal transduction,in turn caused by the lack of Themis.We found that upon TCR stimulation,Themis-deficient CD4^(+)T cells were unable to upregulate the expression of insulin receptor(IR),glucose transporter(GLUT1),the neutral amino acid transporter CD98 and the mTOR pathway,as measured by c-Myc and pS6 expression.Mitochondrial analysis of activated Themis-deficient CD4^(+)T cells showed more oxidative phosphorylation(OXPHOS)than aerobic glycolysis,indicating defective metabolic reprogramming.Furthermore,we found reduced NFAT translocation in Themis-deficient CD4^(+)T cells upon TCR stimulation.Using previously reported ChIP-seq and RNA-seq data,we found that NFAT nuclear translocation controls IR gene expression.Together,our results describe an internal circuit between TCR signal transduction,NFAT nuclear translocation,and metabolic signaling in CD4^(+)T cells.

Effects of nuclear translocation of tissue transglutaminase and the release of cytochrome C on hepatocyte apoptosis

Objective To assess the effects of nuclear translocation of tissue transglutaminase (TTG) and the release of cytochrome C on hepatocyte apoptosis and to reveal the mechanism of signal transduction of early apoptosis in injured hepatocytes. Methods Hepatocytes isolated from tissue transglutaminase gene knock-out mice and rats were stimulated with ethanol. Proteins from whole cell, cytoplasm and nuclei were extracted for determination of TTG activity by 14C-putrescine incorporation. Distribution of TTG throughout the entire cell, as well as just nucleus was observed under a confocal scanning microscope. The amount of cytochrome C released from mitochondria was determined by ELISA. Cell apoptosis was observed by fluorescent cytochemistry.Results TTG activity in whole cells and nuclei was significantly increased after the hepatocytes were treated with ethanol. Cytochrome C release was remarkably increased in the cells isolated from rat and wild-type mouse after treatment with ethanol but not in TTG gene knock-out mice. Cellular apoptosis appeared in hepatocytes isolated from rats and wild-type mice but not in the hepatocytes from TTG gene knock-out mice after stimulation with ethanol.Conclusions Increased TTG in hepatocytes can be translocated into the nucleus and promote release of mitochondrial cytochrome C into the cytoplasm. Passing through a series of signal pathways, hepatocyte apoptosis is induced eventually.

Aryl hydrocarbon receptor nuclear translocator 2 as a prognostic biomarker and immunotherapeutic indicator for clear cell renal cell carcinoma

Background:In many cancer types,aryl hydrocarbon receptor nuclear translocator 2(ARNT2)has been found to be associated with tumor cell proliferation and prognosis.However,the role of ARNT2 in clear cell renal cell carcinoma(ccRCC)has not been completely elucidated.In this study,the potential role of ARNT2 in ccRCC development was characterized.Methods:A pan-cancer dataset(TCGA-TARGET-GTEx)was accessed from UCSC Xena Data Browser.ARNT2 expression in normal and tumor samples was compared.Univariate Cox regression was performed to evaluate the prognostic value of ARNT2.Single sample gene set enrichment analysis(ssGSEA)was used to estimate the enrichment of functional pathways and gene signatures.CIBERSORT and ESTIMATE methods evaluated the immune infiltration.The ARNT2 expression was determined in ccRCC tissue and cell lines using RT-qPCR and Western blot.Results:ARNT2 expression was significantly dysregulated in 23 out of 30 cancer types.Pan-cancer data revealed a strong correlation between ARNT2 expression and immune modulators,immune cell infiltration,and genomic alternations.In ccRCC patients,the low-ARNT2 expression group had higher immune infiltration,CD8 T cells,and programmed cell death ligand 1 expression,as well as higher enrichment score of immunotherapeutic predictors than those in the high-ARNT2 expression group.Low-ARNT2 expression group was more responsive to immunotherapy.Moreover,low ARNT2 expression was observed in ccRCC tissue and cell lines.Conclusions:Dysregulated ARNT2 expression is involved in cancer development and the modulation of the immune microenvironment.ARNT2 can be potentially used as a prognostic indicator and an immunotherapeutic indicator for ccRCC.

Maintaining moderate levels of hypochlorous acid promotes neural stem cell proliferation and differentiation in the recovery phase of stroke

It has been shown clinically that continuous removal of ischemia/reperfusion-induced reactive oxygen species is not conducive to the recovery of late stroke.Indeed,previous studies have shown that excessive increases in hypochlorous acid after stroke can cause severe damage to brain tissue.Our previous studies have found that a small amount of hypochlorous acid still exists in the later stage of stroke,but its specific role and mechanism are currently unclear.To simulate stroke in vivo,a middle cerebral artery occlusion rat model was established,with an oxygen-glucose deprivation/reoxygenation model established in vitro to mimic stroke.We found that in the early stage(within 24 hours)of ischemic stroke,neutrophils produced a large amount of hypochlorous acid,while in the recovery phase(10 days after stroke),microglia were activated and produced a small amount of hypochlorous acid.Further,in acute stroke in rats,hypochlorous acid production was prevented using a hypochlorous acid scavenger,taurine,or myeloperoxidase inhibitor,4-aminobenzoic acid hydrazide.Our results showed that high levels of hypochlorous acid(200μM)induced neuronal apoptosis after oxygen/glucose deprivation/reoxygenation.However,in the recovery phase of the middle cerebral artery occlusion model,a moderate level of hypochlorous acid promoted the proliferation and differentiation of neural stem cells into neurons and astrocytes.This suggests that hypochlorous acid plays different roles at different phases of cerebral ischemia/reperfusion injury.Lower levels of hypochlorous acid(5 and 100μM)promoted nuclear translocation ofβ-catenin.By transfection of single-site mutation plasmids,we found that hypochlorous acid induced chlorination of theβ-catenin tyrosine 30 residue,which promoted nuclear translocation.Altogether,our study indicates that maintaining low levels of hypochlorous acid plays a key role in the recovery of neurological function.

INVESTIGATION OF LATENT NUCLEAR LOCALIZATION SEQUENCE(NLS) OF STAT

Objective: To investigate the latent nuclear localization sequence (NLS) OF STAT3. Methods: Clustal X (1.81) was used to alignment the DNA binding domain of the STAT family. According to structure characters, corresponding expression plasmids were constructed via oligonucleotides designed with gene tool software. Through in vitro transfection, images were observed with laser confocal microscopy. Results: homology positions of arginine and lysine were found in DNA binding domain of the stat family. The wild type-STAT3 proteins primarily localized in the cytoplasm and translocated into the nucleus after interleukin-6 stimulation. However, the truncated mutant of DSTAT3-GFP protein was exclusively expressed in the cytoplasm. Conclusion: The potential NLS in the DNA binding domain of STAT3 is exposed to nuclear importing receptor when cells are stinulated by cytokine, which promotes the translocation of STAT3 into nuclear.

Withaferin A inhibits ferroptosis and protects against intracerebral hemorrhage

Recent studies have indicated that suppressing oxidative stress and ferroptosis can considerably improve the prognosis of intracerebral hemorrhage(ICH).Withaferin A(WFA),a natural compound,exhibits a positive effect on a number of neurological diseases.However,the effects of WFA on oxidative stress and ferroptosis-mediated signaling pathways to ICH remain unknown.In this study,we investigated the neuroprotective effects and underlying mechanism for WFA in the regulation of ICH-induced oxidative stress and ferroptosis.We established a mouse model of ICH by injection of autologous tail artery blood into the caudate nucleus and an in vitro cell model of hemin-induced ICH.WFA was injected intracerebroventricularly at 0.1,1 or 5μg/kg once daily for 7 days,starting immediately after ICH operation.WFA markedly reduced brain tissue injury and iron deposition and improved neurological function in a dose-dependent manner 7 days after cerebral hemorrhage.Through in vitro experiments,cell viability test showed that WFA protected SH-SY5Y neuronal cells against hemin-induced cell injury.Enzyme-linked immunosorbent assays in vitro and in vivo showed that WFA markedly decreased the level of malondialdehyde,an oxidative stress marker,and increased the activities of anti-oxidative stress markers superoxide dismutase and glutathione peroxidase after ICH.Western blot assay,quantitative polymerase chain reaction and immunofluorescence results demonstrated that WFA activated the nuclear factor E2-related factor 2(Nrf2)/heme oxygenase-1(HO-1)signaling axis,promoted translocation of Nrf2 from the cytoplasm to nucleus,and increased HO-1 expression.Silencing Nrf2 with siRNA completely reversed HO-1 expression,oxidative stress and protective effects of WFA.Furthermore,WFA reduced hemin-induced ferroptosis.However,after treatment with an HO-1 inhibitor,the neuroprotective effects of WFA against hemin-induced ferroptosis were weakened.MTT test results showed that WFA combined with ferrostatin-1 reduced hemin-induced SH-SY5Y neuronal cell injury.Our findings reveal that WFA treatment alleviated ICH injury-induced ferroptosis and oxidative stress through activating the Nrf2/HO-1 pathway,which may highlight a potential role of WFA for the treatment of ICH.

Integrating network pharmacology and pharmacological evaluation for deciphering the mechanism of(-)-epigallocatechin-3-gallate alleviating ethanol-induced endothelial cells injury

Objective To investigate the potential therapeutic targets and pharmacological mechanism of(-)-epigallocatechin-3-gallate(EGCG)based on network pharmacology and experimental verification.METHODS The druggability of EGCG was measured by the traditional Chinese medicine systems pharmacology(TCMSP)server,and potential targets of EGCG were identified by Pharm Mapper and Drug Repositioning and Adverse drug Reaction via Chemical-Protein Interactome(DRAR-CPI).The potential targets were imported into GeneMANIA database to obtain the protein-protein direct interaction network,and target physical interaction,co-expression,prediction,genetic interaction,and shared protein domains.The biological process,molecular functions,cellular components and KEGG signaling pathways of potential targets were analyzed using DAVID database.For further study,ethanol was used to establish a model of endothelial injury in vitro.The cell viability was assayed by MTT method,the cellular apoptosis was stained by Annexin V/PI,and the expression levels of Bcl-2,Bax and cleved-caspase-3 were tested by Western blotting.Then,JC-1 and nuclear translocation of NF-κB experiments were used to study the mitochondrial membrane potential and nuclear translocation.RESULTS The oral availability of EGCG was 55.09%(≥30%)and drug-like index was 0.77(≥0.18),which were considered pharmacokinetically active.17 potential targetable proteins of EGCG were predicted by Pharm Mapper and DRAR-CPI.Further research showed that 68.13%displayed similar co-expression characteristics,26.11%physical interactions,and 2.74%shared the same protein domain.The depth network analysis results showed that the biofunctions of EGCG were mainly by regulating glutathione derivative biosynthetic process,glutathione metabolic process,nitrogen compound metabolic process etc..via drug binding,catalytic activity,glutathione transferase activity,anion binding etc..in sarcoplasmic reticulum,spindle pole,microtubule cytoskeleton and cytoplasm.KEGG enrichment analysis showed that Glutathione metabolism,IL^(-1)7 signaling pathway,EGFR tyrosine kinase inhibitor resistance,PI3K-Akt signaling pathway and other pathways were involves in the biofunction of EGCG.The above analyses indicated that EGCG exerts its biofunction through antioxidant and anti-inflammatory mechanisms.The experimental results showed that ethanol 20.0 mmol·L^(-1) decreased cell viability,Bcl-2 expression,and increased cell apoptosis,the intracellular ROS,as well as the expression of Bax and cleaved-caspase-3 of human endothelial cells.However,treatment of the cells with EGCG can significantly alleviate ethanol induced endothelial cells injury.Further study showed that EGCG significantly alleviates ethanol induced mitochondrial depolarization and nuclear translocation of NF-κB.CONCLUSIONS EGCG exerts pharmacological efficacies on ethanol induced endothelial cell injury through multi-target,multi-function and multi-pathway mode.Protective effect of EGCG on ethanol induced cell injury was mainly through alteration of mitochondrial function and NF-κB translocation.Therefore,EGCG have great potential in protecting against endothelial dysfunction of the persons who are chronically abuse of ethanol.This study also provides a new understanding of EGCG in clinical application on cardiovascular and cerebrovascular diseases.

Protocatechuic aldehyde protects cardiomycoytes against ischemic injury via regulation of nuclear pyruvate kinase M2

Rescuing cells from stress damage emerges a potential therapeutic strategy to combat myocardial infarction.Protocatechuic aldehyde(PCA)is a major phenolic acid in Chinese herb Danshen(Salvia miltiorrhiza root).This study investigated whether PCA regulated nuclear pyruvate kinase isoform M2(PKM2)function to protect cardiomyocytes.In rats subjected to isoprenaline,PCA attenuated heart injury and protected cardiomyocytes from apoptosis.Through DARTS and CETSA assays,we identified that PCA bound and promoted PKM2 nuclear translocation in cardiomyocytes exposed to oxygen/glucose deprivation(OGD).In the nucleus,PCA increased the binding of PKM2 to β-Catenin via preserving PKM2 acetylation,and the complex,in cooperation with T-cell factor 4(TCF4),was required for transcriptional induction of genes encoding anti-apoptotic proteins,contributing to rescuing cardiomyocyte survival.In addition,PCA ameliorated mitochondrial dysfunction and prevented mitochondrial apoptosis dependent on PKM2.Consistently,PCA increased the binding of PKM2 to β-Catenin,improved heart contractive function,normalized heart structure and attenuated oxidative damage in mice subjected to artery ligation,but the protective effects were lost in Pkm2-deficient heart.Together,we showed that PCA regulated nuclear PKM2 function to rescue cardiomyocyte survival via β-Catenin/TCF4 signaling cascade,suggesting the potential of pharmacological intervention of PKM2 shuttle to protect the heart.

Intranuclear cardiac troponin I plays a functional role in regulating Atp2a2 expression in cardiomyocytes

In the past studies,it is shown that cardiac troponin I(cTnI,encoded by TNNI3),as a cytoplasmic protein,is an inhibitory subunit in troponin complex,and involves in cardiomyocyte diastolic regulation.Here,we assessed a novel role of cTnI as a nucleoprotein.Firstly,the nuclear translocation of cTnI was found in mouse,human fetuses and rat heart tissues.In addition,there were differences in percentage of intranuclear cTnI in different conditions.Based on weighted gene co-expression network analyses(WGCNA)and verification in cell experiments,a strong expression correlation was found between TNNI3 and Atp2a2,which encodes sarco-endoplasmic reticulum Ca2t ATPase isoform 2a(SERCA2a),and involves in ATP hydrolysis and Ca2t transient.TNNI3 gain and loss caused Atpa2a2 increase/decrease in a dosedependent manner both in mRNA and protein levels,in vivo and in vitro.By using ChIP-sequence we demonstrated specific binding DNA sequences of cTnI were enriched in ATP2a2 promoter239we889 region and the specific binding sequence motif of cTnI was analyzed by software as"CCAT",which has been reported to be required for YY1 binding to the promoter region of YY1-related genes.Moreover,it was further verified that pcDNA3.1()-TNNI3 could express cTnI proteins and increase the promoter activity of Atp2a2 through luciferase report assay.In the end,we evaluated beat frequencies,total ATP contents,Ca2t transients in TNNI3-siRNA myocardial cells.These findings indicated,for the first time,cTnI may regulate Atp2a2 in cardiomyocytes as a co-regulatory factor and participate in the regulation of intracellular Ca ions.

Nuclear cGAS: sequestration and beyond

The cyclic GMP-AMP(cGAMP)synthase(cGAS)has been identified as a cytosolic double stranded DNA sensor that plays a pivotal role in the type I interferon and inflammation responses via the STING-dependent signaling pathway.In the past several years,a growing body of evidence has revealed that cGAS is also localized in the nucleus where it is associated with distinct nuclear substructures such as nucleosomes,DNA replication forks,the double-stranded breaks,and centromeres,suggesting that cGAS may have other functions in addition to its role in DNA sensing.However,while the innate immune function of cGAS is well established,the non-canonical nuclear function of cGAS remains poorly understood.Here,we review our current understanding of the complex nature of nuclear cGAS and point to open questions on the novel roles and the mechanisms of action of this protein as a key regulator of cell nuclear function,beyond its well-established role in dsDNA sensing and innate immune response.

Dihydrotanshinone I preconditions myocardium against ischemic injury via PKM2 glutathionylation sensitive to ROS

Ischemic preconditioning(IPC)is a potential intervention known to protect the heart against ischemia/reperfusion injury,but its role in the no-reflow phenomenon that follows reperfusion is unclear.Dihydrotanshinone I(DT)is a natural compound and this study illustrates its role in cardiac ischemic injury from the aspect of IPC.Pretreatment with DT induced modest ROS production and protected cardiomyocytes against oxygen and glucose deprivation(OGD),but the protection was prevented by a ROS scavenger.In addition,DT administration protected the heart against isoprenaline challenge.Mechanistically,PKM2 reacted to transient ROS via oxidization at Cys423/Cys424,leading to glutathionylation and nuclear translocation in dimer form.In the nucleus,PKM2 served as a co-factor to promote HIF-1a-dependent gene induction,contributing to adaptive responses.In mice subjected to permanent coronary ligation,cardiac-specific knockdown of Pkm2 blocked DT-mediated preconditioning protection,which was rescued by overexpression of wild-type Pkm2,rather than Cys423/424-mutated Pkm2.In conclusion,PKM2 is sensitive to oxidation,and subsequent glutathionylation promotes its nuclear translocation.Although IPC has been viewed as a protective means against reperfusion injury,our study reveals its potential role in protection of the heart from no-reflow ischemia.

Activated PKB/GSK-3β synergizes with PKC-δ signaling in attenuating myocardial ischemia/reperfusion injury via potentiation of NRF2 activity: Therapeutic efficacy of dihydrotanshinone-Ⅰ

Disrupted redox status primarily contributes to myocardial ischemia/reperfusion injury(MIRI).NRF2,the endogenous antioxidant regulator,might provide therapeutic benefits.Dihydrotanshinone-Ⅰ(DT)is an active component in Salvia miltiorrhiza with NRF2 induction potency.This study seeks to validate functional links between NRF2 and cardioprotection of DT and to investigate the molecular mechanism particularly emphasizing on NRF2 cytoplasmic/nuclear translocation.DT potently induced NRF2 nuclear accumulation,ameliorating post-reperfusion injuries via redox alterations.Abrogated cardioprotection in NRF2-deficient mice and cardiomyocytes strongly supports NRF2-dependent cardioprotection of DT.Mechanistically,DT phosphorylated NRF2 at Ser40,rendering its nuclear-import by dissociating from KEAP1 and inhibiting degradation.Importantly,we identified PKC-δ-(Thr505)phosphorylation as primary upstream event triggering NRF2-(Ser40)phosphorylation.Knockdown of PKC-δdramatically retained NRF2 in cytoplasm,convincing its pivotal role in mediating NRF2 nuclear-import.NRF2 activity was further enhanced by activated PKB/GSK-3βsignaling via nuclear-export signal blockage independent of PKC-δactivation.By demonstrating independent modulation of PKC-δand PKB/GSK-3β/Fyn signaling,we highlight the ability of DT to exploit both nuclear import and export regulation of NRF2 in treating reperfusion injury harboring redox homeostasis alterations.Coactivation of PKC and PKB phenocopied cardioprotection of DT in vitro and in vivo,further supporting the potential applicability of this rationale.

FLOWERING LOCUS M isoforms differentially affect the subcellular localization and stability of SHORT VEGETATIVE PHASE to regulate temperature-responsive flowering in Arabidopsis

Temperature is an important environmental cue that affects flowering time in plants.The MADS-box transcription factor FLOWERING LOCUS M(FLM)forms a heterodimeric complex with SHORT VEGETATIVE PHASE(SVP)and controls ambient temperature-responsive flowering in Arabidopsis.FLM-βand FLM-δ,two major splice variants produced from the FLM locus,exert opposite effects on flowering,but the molecular mechanism by which the interaction between FLM isoforms and SVP affects temperature-responsive flowering remains poorly understood.Here,we show that FLM-βand FLM-δplay important roles in modulating the temperature-dependent behavior,conformation,and stability of SVP.Nuclear localization of SVP decreases as temperature increases.FLM-βis required for SVP nuclear translocation at low temperature,whereas SVP interacts with FLM-δmainly in the cytoplasm at high temperature.SVP preferentially binds to FLM-βat low temperature in tobacco leaf cells.SVP shows high binding affinity to FLM-βat low temperature and to FLM-δat high temperature.SVP undergoes similar structural changes in the interactions with FLM-βand FLM-δ;however,FLM-δlikely causes more pronounced conformational changes in the SVP structure.FLM-δcauses rapid degradation of SVP at high temperature,compared with FLM-β,possibly via ubiquitination.Mutation of lysine 53 or lysine 165 in SVP causes increased abundance of SVP due to reduced ubiquitination of SVP and thus delays flowering at high temperature.Our findings suggest that temperature-dependent differential interactions between SVP and FLM isoforms modulate the temperature-responsive induction of flowering in Arabidopsis.

Hepatoprotective and antioxidant effects of dietary Glycyrrhiza polysaccharide against TCDD-induced hepatic injury and RT-PCR quantification of AHR2,ARNT2,CYPIA mRNA in Jian Carp(Cyprinus carpio var.Jian)

To evaluate the protective effects of Glycyrrhiza polysaccharide（GPS） against 2,3,7,8-tetrachlorodibenzo-p-dioxin（TCDD）-induced hepatotoxicity in Jian carp,the fish were fed diets containing GPS at doses of 0.1,0.5 and 1.0 g/kg for 60 days before an intraperitoneal injection of 0.6 μg/kg TCDD at a volume of 0.05 mL/10 g body weight.At 72 hr post-injection,blood and liver samples were taken for biochemical analysis and the fish liver samples were used for the preparation of pathological slices.The results showed that increases in alanine aminotransferase（GPT）,aspartate aminotransferase（GOT）,lactate dehydrogenase（LDH）,and alkaline phosphatase（AKP） in serum induced by TCDD were significantly inhibited by pre-treatment with 1.0 g/kg GPS.Following the 1.0 g/kg GPS pre-treatment,total protein（TP）,albumin（Alb）,catalase（CAT）,glutathione peroxidase（GPx）,total antioxidant capacity（T-AOC） and superoxide dismutase（SOD） activities in liver tissue increased significantly,malondialdehyde（MDA） formation（P ＆lt; 0.05 or P ＆lt; 0.01） was significantly inhibited,and the expression of cytochrome P4501A（CYP1A）,aryl hydrocarbon receptor 2（AHR2） and aryl hydrocarbon receptor nuclear translocator 2（ARNT2） mRNA（P ＆lt; 0.05） was significantly enhanced.Histological observations on fish liver were obtained by preparing paraffin tissue sections via HE staining,and the results showed that histological changes were obviously reduced by 0.5 and 1.0 g/kg GPS.GPS significantly reduced liver tissue damage caused by TCDD.Overall,these results proved the hepatoprotective effect of GPS in protecting against fish liver injury induced by TCDD,and supported the use of GPS（1.0 g/kg） as a hepatoprotective and antioxidant agent in fish.