Ghrelin通过JNK信号通路抑制LPS诱导的肺泡巨噬细胞凋亡

【目的】观察体外条件下加入外源性ghrelin对内毒素(LPS)诱导大鼠肺泡巨噬细胞NR8383凋亡以及吞噬能力的影响,并探讨JNK(c-Jun N-terminal kinase)信号通路在其中所起的作用。【方法】用CCK-8(Cell Counting Kit-8)法检测加入LPS或者ghrelin与LPS共孵育后NR8383的细胞毒性;流式细胞技术、原位末端标记法(TUNEL)检测细胞凋亡率;Western blot检测JNK、phospho-JNK信号通路蛋白以及cleaved caspase-3、Bax、Bcl-2凋亡相关分子蛋白的表达;激光共聚焦技术检测巨噬细胞的吞噬能力;使用ghrelin受体拮抗剂[D-Lys-3]-GHRP-6、JNK特异性抑制剂SP600125分别抑制ghrelin受体及JNK激酶的激活。【结果】CCK-8检测结果显示LPS可显著抑制NR8383增殖,而ghrelin可呈浓度依赖性地阻断这种抑制作用;流式和TUNEL检测进一步证实ghrelin可显著降低LPS所致NR8383凋亡作用(P<0.05),而应用ghrelin受体拮抗剂[D-Lys-3]-GHRP-6可以减弱ghrelin的抗凋亡效果(P<0.05);LPS可以激活JNK激酶活性,并改变其下游凋亡相关蛋白的表达,其中促凋亡蛋白Bax以及cleaved caspase-3表达上调,抗凋亡蛋白Bcl-2表达下调,应用ghrelin可以逆转LPS对JNK激酶的激活,继而下调Bax以及cleaved caspase-3的表达,上调Bcl-2的表达,差异均具有统计学意义(P<0.05);ghrelin还可以维持LPS持续刺激下NR8383的吞噬能力(P<0.05)。【结论】ghrelin通过下调JNK信号通路的激活抑制LPS诱导的NR8383的凋亡,并维持其吞噬能力。

Interleukin-1 beta up-regulates tissue inhibitor of matrix metalloproteinase-1 mRNA and phosphorylation of c-jun N-terminal kinase and p38 in hepatic stellate cells

AIM： To study the relationship between interleukin-lbeta （IL-1β） up-regulating tissue inhibitor of matrix metalloproteinase-1 （TIMMP-1） mRNA expression and phosphorylation of both c-jun N-terminal kinase （INK） and p38 in rat heffatic stellate cells （HSC）. METHODS： RT-PCR was performed to measure the expression of TIMMP-1 mRNA in rat HSC. Western blot was performed to measure IL-1β-induced JNK and p38 activities in rat HSC. RESULTS： TIMMP-1 mRNA expression （1.191± 0.079） was much higher after treatment with IL-1β （10 ng/mL） for 24 h than in control group （0.545±0.091） （P〈0.01）. IL-1β activated INK and p38 in a time-dependent manner. After stimulation with IL-1β for 0, 5, 15, 30, 60 and 120 min, the INK activity was 0.982±0.299, 1.501±0.720, 2.133±0.882, 3.360±0.452, 2.181±0.789, and 1.385 ± 0.368, respectively. There was a significant difference in JNK activity at 15 min （P〈 0.01）, 30 min （P〈 0.01） and 60 min （P〈0.01） in comparison to that at 0 min. The p38 activity was 1.061±0.310, 2.050±0.863, 2.380±0.573, 2.973±0.953, 2.421±0.793, and 1.755 ± 0.433 at the 6 time points （0, 5, 15, 30, 60 and 120 min） respectively. There was a significant difference in p38 activity at 5 min （P〈0.05）, 15 min （P〈0.01）, 30 min （P〈0.01） and 60 min （P〈0.01） compared to that at 0 min. TIMMP-1 mRNA expression trended to decrease in 3 groups pretreated with different concentrations of SP600125 （10 μmol/L, 1.022±0.113; 20 μmol/L, 0.869±0.070; 40 μmol/L, 0.666±0.123）. Their decreases were all significant （P〈0.05, P〈0.01, P〈0.01） in comparison to control group （without SP600125 treatment, 1.163±0.107）. In the other 3 groups pretreated with different concentrations of SB203580 （10 μmol/L, 1.507±0.099; 20 μmol/L, 1.698±0.107; 40 μmol/L, 1.857±0.054）, the expression of TIMMP-1 mRNA increased. Their levels were higher than those in the control group （without SB203580 treatment, 1.027 ± 0.061） with a significant statistical significance （P〈 0.01）. CONCLUSION： IL-1β has a direct action on hepatic fibrosis by up-regulating TIMMP-1 mRNA expression in ratessionin in rate HSC.JNK and p38 mitogen-activated protein kinases （MAPKs） are involved in IL-1β-induced TIMMP-1 gene expression, and play a distinct role in this process, indicating that p38 and .INK pathways cooperatively mediate TIMP-1 mRNA expression in rat HSC.

Role of JNK signaling pathway in sensitivity to radiotherapy of nasopharyngeal carcinoma

Objective:The aim of the study was to investigate the effect of c-Jun N-terminal protein kinase(JNK) signaling pathway on influencing the sensitivity to radiotherapy of human nasopharyngeal carcinoma CNE cells.Methods:Human nasopharyngeal carcinoma CNE multicellular spheroids(MCS) were constructed with three dimensional cell culture methods.Western blot was employed to analyze the activity of JNK signaling pathway in MCS after X-ray irradiation,and the expression of caspase-3 protein before and after using SP600125(a special inhibitor of JNK).X-ray induced cell apoptosis in MCS before and after treated with SP600125 were detected by TUNEL.Results:The level of JNK phosphorylation in MCS was a dynamic course after radiation,and there was a phosphorylation peaks at 2 h later,the apoptotic rate of MCS(P < 0.05) and the expression of caspase-3 protein(P < 0.05) were significantly increased after treated with SP600125.Conclusion:The transient activation of JNK played a important role in sensitivity to radiotherapy of CNE MCS via mediating survival signals,blocking this pathway accelerate cell apoptosis,which may be related to the increased expression of caspase-3.

血浆JNK1与肺循环高压发生发展的相关性分析

目的:通过调查湖南地区部分肺循环高压(PH)患者人群及健康人群血浆JNK1浓度水平,揭示PH患者血清中JNK1表达水平与肺循环高压的发生发展之间的相关性,为PH的早期预防、早期诊断治疗奠定基础。方法:采用横断面调查方法,测定64例肺循环高压患者(肺循环高压组)空腹血浆JNK1水平,并与30例正常健康人群(正常对照组)空腹血浆JNK1水平比较。结果:肺循环高压组血浆JNK1水平与正常对照组比较,差异无统计学意义(P>0.05)。线性回归分析结果提示:血浆JNK1浓度与肺动脉平均压力之间无明显相关性(P>0.05),与左心疾病相关的肺循环高压(PHALH)小组(n=27)、与缺氧或呼吸系统疾病相关的肺循环高压(PHAHR)小组(n=19)与正常对照组JNK1水平比较,差异有统计学意义(P<0.05);PH患者与左心疾病相关的肺循环高压(PHALH)小组(n=27)、与缺氧或呼吸系统疾病相关的肺循环高压(PHAHR)小组(n=19)血清中JNK1表达水平与肺动脉平均压之间差异有统计学意义(P<0.05)。结论:就肺循环高压患者总体而言,血浆JNK1水平与肺动脉高压的发生发展似乎不相关。但是,在发病机制相似的某一PH患者人群中,血清中JNK1表达水平与肺动脉高压的发生发展之间可能存在相关性。血浆JNK1浓度水平,也许可以作为PH疾病发生发展严重程度的一个标志物。

Down-regulation of HIV-1 Infection by Inhibition of the MAPK Signaling Pathway

The human immunodeficiency virus type 1 （HIV-1） can interact with and exploit the host cellular machinery to replicate and propagate itself. Numerous studies have shown that the Mitogen-activated protein kinase （MAPK） signal pathway can positively regulate the replication of HIV-1, but exactly how each MAPK pathway affects HIV-1 infection and replication is not understood. In this study, we used the Extracellular signal-regulated kinase （ERK） pathway inhibitor, PD98059, the Jun N-terminal kinase （JNK） pathway inhibitor, SP600125, and the p38 pathway inhibitor, SB203580, to investigate the roles of these pathways in HIV-1 replication. We found that application of PD98059 results in a strong VSV-G pseudotyped HIV-1NL4-3 luciferase reporter virus and HIV-1NL4-3 virus inhibition activity. In addition, SB203580 and SP600125 also elicited marked VSV-G pseudotyped HIV-INL4-3 luciferase reporter virus inhibition activity but no HIV-1NL4-3 virus inhibition activity. We also found that SB203580 and SP600125 can enhance the HIV-1 inhibition activity of PD98059 when cells were treated with all three MAPK pathway inhibitors in combination. Finally, we show that HIV-1 virus inhibition activity of the MAPK pathway inhibitors was the result of the negative regulation of HIV-1 LTR promoter activity.

Toxicities of amyloid-beta and tau protein are reciprocally enhanced in the Drosophila model

Extracellular aggregation of amyloid-beta(Aβ)and intracellular tau tangles are two major pathogenic hallmarks and critical factors of Alzheimer’s disease.A linear interaction between Aβand tau protein has been characterized in several models.Aβinduces tau hyperphosphorylation through a complex mechanism;however,the master regulators involved in this linear process are still unclear.In our study with Drosophila melanogaster,we found that Aβregulated tau hyperphosphorylation and toxicity by activating c-Jun N-terminal kinase.Importantly,Aβtoxicity was dependent on tau hyperphosphorylation,and flies with hypophosphorylated tau were insulated against Aβ-induced toxicity.Strikingly,tau accumulation reciprocally interfered with Aβdegradation and correlated with the reduction in mRNA expression of genes encoding Aβ-degrading enzymes,including dNep1,dNep3,dMmp2,dNep4,and dIDE.Our results indicate that Aβand tau protein work synergistically to further accelerate Alzheimer’s disease progression and may be considered as a combined target for future development of Alzheimer’s disease therapeutics.

TRAF2-MLK3 interaction is essential for TNF-α-induced MLK3 activation

Mixed lineage kinase 3 （MLK3） is a mitogen-activated protein kinase kinase kinase that is activated by tumor necrosis factor-α （TNF-α） and specifically activates c-Jun N-terminal kinase （JNK） on TNF-a stimulation. The mecha- nism by which TNF-α activates MLK3 is still not known. TNF receptor-associated factors （TRAFs） are adapter molecules that are recruited to cytoplasmic end of TNF receptor and mediate the downstream signaling, including activation of JNK. Here, we report that MLK3 associates with TRAF2, TRAF5 and TRAF6; however only TRAF2 can significantly induce the kinase activity of MLK3. The interaction domain of TRAF2 maps to the TRAF domain and for MLK3 to its C-terminal half （amino acids 511-847）. Endogenous TRAF2 and MLK3 associate with each other in response to TNF-α treatment in a time-dependent manner. The association between MLK3 and TRAF2 mediates MLK3 activation and competition with the TRAF2 deletion mutant that binds to MLK3 attenuates MLK3 kinase activity in a dose-dependent manner, on TNF-α treatment. Furthermore the downstream target of MLK3, JNK was activated by TNF-α in a TRAF2-dependent manner. Hence, our data show that the direct interaction between TRAF2 and MLK3 is required for TNF-α-induced activation of MLK3 and its downstream target, JNK.

Puerarin reduces apoptosis in rat hippocampal neurons cultured in high glucose medium by modulating the p38 mitogen activated protein kinase and c-Jun N-terminal kinase signaling pathways

OBJECTIVE: To investigate the neuroprotective effect of puerarin on rat hippocampal neurons cultured in high glucose medium, and to examine the role of the p38 mitogen activated protein kinase(p38 MAPK) and c-Jun N-terminal kinase(JNK) signaling pathways in this effect.METHODS: Primary cultures of hippocampal neurons were prepared from newborn Sprague Dawley rats. Neuron-specific enolase immunocytochemistry was used to identify neurons. The neurons were cultured with normal medium(control group) or with high-glucose medium(high-glucose group),and puerarin(puerarin group), a p38 MAPK inhibitor(SB239063; p38 MAPK inhibitor group) or a JNK inhibitor(SP600125; JNK inhibitor group) were added. After 72 h of treatment, terminal deoxynucleotidyl transferase-mediated d UTP nick end labeling assay was performed to detect apoptosis, and western blotting was used to assess protein levels of p-p38, p38, p-JNK and JNK.RESULTS: In the high-glucose group, the neuronal apoptosis rate and the p-p38/p38 and p-JNK/JNK ratios were higher than in the control group. The p38 MAPK and JNK inhibitors prevented this increase in the apoptosis rate. The apoptosis rates in the puerarin group, the p38 MAPK inhibitor group and the JNK inhibitor group were significantly decreased compared with the high-glucose group.Moreover, protein levels of p-p38 and p-JNK were significantly reduced, and the p-p38/p38 and p-JNK/JNK ratios were decreased in the puerarin group compared with the high-glucose group. In addition, compared with the high-glucose group,p-p38 levels and the p-p38/p38 ratio were reduced in the p38 MAPK inhibitor group, and p-JNK levels and the p-JNK/JNK ratio were decreased in the JNK inhibitor group.CONCLUSION: Puerarin attenuates neuronal apoptosis induced by high glucose by reducing the phosphorylation of p38 and JNK.

Protective effect of Chushizi(Fructus Broussonetiae)on acetaminophen-induced rat hepatitis by inhibiting the Toll-like receptor 3/c-Jun N-terminal kinase/c-jun/c-fos/janus protein tyrosine kinase/activators of transcription 3 pathway

OBJECTIVE:To observe the intervention of Chushizi(Fructus Broussonetiae)(CSZ)on drug-induced liver injury(DILI)in rats,as well as indicators of liver function,serum levels of inflammatory cytokines,and expression of proteins and m RNA associated with toll-like receptor 3(TLR3)and the signal transducer and activator of transcription 3(STAT3)pathway in the liver[TLR3,janus protein tyrosine kinase 2(JAK2),c-jun,c-fos,c-Jun N-terminal kinase 2(JNK2),and STAT3].METHODS:Forty specified pathogen free grade Sprague-Dawley rats were randomly divided into the control group,the model group,the silybin group and the CSZ group.Rats were given acetaminophen(APAP)to trigger DILI.Histopathology of the liver was observed by hematoxylin-eosin staining.The levels of alanine aminotransferase(ALT),aspartate transaminase(AST),direct bilirubin(DBIL),and total bilirubin(TBIL)in serum were detected by a semi-automatic biochemical instrument.Content of tumor necrosis factor alpha(TNF-α),interleukin(IL)-6,IL-13,and IL-22 in serum were detected by the enzyme-linked immunosorbent assay,the expression of TLR3,phosphorylation of JAK2(p-JAK2),while c-jun and c-fos proteins in the liver were determined by immunohistochemistry;expression of JNK2,and STAT3 in the liver were assayed by Western blot and real-time quantitative polymerase chain reaction.P-JNK2 and p-STAT3 in the liver were assayed by Western blot.RESULTS:After treatment,the activity of ALT,AST,and concentrations of TBIL,DBIL,TNF-α,IL-6,as well as IL-13 in serum,were lower than those in the model group,and expression of p-JAK2,TLR3,c-jun,c-fos,p-STAT3,and p-JNK2 could be downregulated.CONCLUSION:Our findings suggest that CSZ is a valid medicine to alleviate APAP-induced DILI,while its partial mechanism may regulate the TLR3/JNK/c-jun/c-fos/JAK/STAT3 pathway.

Efficacy of Cigu Xiaozhi pill(慈菇消脂丸) on non-alcoholic steatohepatitis-associated lipoapoptosis through stress-activated c-Jun N-terminal kinase signalling pathway

OBJECTIVE: To investigate the efficacy of Cigu Xiaozhi pill(慈菇消脂丸, CGXZ) on non-alcoholic steatohepatitis(NASH)-associated lipoapoptosis through the stress-activated c-Jun N-terminal kinase(JNK)/stress-activated protein kinase signalling pathway.METHODS: Sixty male Sprague-Dawley rats were randomly divided into the following groups(10 rats each): blank control, model, low-dose CGXZ,medium-dose CGXZ, high-dose CGXZ, and positive control(treated with SP600125, a JNK inhibitor).The NASH model was established and the histomor-phological characteristics of haematoxylin and eosin-stained liver tissues were examined under a light microscope. Cell apoptosis in liver tissues was assessed via terminal deoxynucleotidyl transferase d UTP nick-end labelling assay. In addition, the m RNA and protein expression levels of p-JNK,p-c-Jun, caspase-8, Fas, and Fas-L were determined via fluorescence-based quantitative real-time PCR,immunohistochemical and Western blot assays.RESULTS: Histopathological examination of the liver showed that the model rats had moderate-to-severe steatosis with infiltration of inflammatory cells as well as significantly higher expression levels of the p-JNK, p-c-Jun, caspase-8, Fas, and Fas-L proteins, compared with those in the blank control group(P < 0.01). Hepatic lobules of the rats in the treatment groups showed significantly reduced vacuolar degeneration and steatosis as well as alleviated inflammatory cell infiltration. The high and medium-dose CGXZ groups exhibited significantly lower m RNA and protein expression levels of p-JNK, p-c-Jun, caspase-8, Fas, and Fas-L, compared with those in the model group(P < 0.05 or P <0.01).CONCLUSION: CGXZ pill inhibited the onset of hepatocyte apoptosis by regulating the expression of p-JNK, p-c-Jun, caspase-8, Fas, and Fas-L, thereby exerting therapeutic effects against NASH.

CSN1 inhibits c-Jun phosphorylation and down-regulates ectopic expression of JNK1

CSN1 is a component of the COP9 signalosome(CSN),a conserved protein complex with pleiotropic functions in many organs and cell types.CSN regulates ubiquitinproteasome dependent protein degradation via the deneddylation and the associated deubiquitination activities.In addition,CSN associates with protein kinases and modulates cell signaling,particularly the activator protein 1(AP-1)pathway.We have shown previously that CSN1 suppresses AP-1 transcription activity and inhibits ultraviolet(UV)and serum activation of c-fos expression.Here we show that CSN1 can inhibit phosphorylation of proto-oncogene c-Jun product and repress c-Jun dependent transcription.Further,CSN1 dramatically downregulates ectopic expression of c-Jun N-terminal kinase 1(JNK1)in cultured cells.The decline in JNK1 is not caused by excessive proteolysis or by 3′UTR-dependent mRNA instability,but by CSN1-dependent repression of one or multiple steps in transcriptional and posttranscriptional mechanisms.Thus,in contrast to CSN5/Jab1,which promotes AP-1 activity,CSN1 displays a negative effect on the AP-1 pathway.Finally,we discuss about the dynamic equilibrium of the CSN complexes in regulation of the AP-1 pathway.

Protein kinase-based neural signaling pathways for ginsenosides:a retrospective review

Ginsenosides are the main active components of ginseng,which have been reported to target brain tissues and produce multiple neuroprotective effects.Ginsenosides have been shown to improve learning ability and memory in normal aged animals,and in an animal model of memory impairment.However,its underlying pharmacological mechanisms are very complicated,especially with regard to its effects on the activation of protein kinases in neurons.Previous reports have shown that some protein kinases may be affected by ginsenosides,including protein kinase C,calcium/calmodulin-dependent protein kinase Ⅱ,c-Jun-N terminal kinase,and protein tyrosine kinase.In this paper,protein kinases that may underlie the mechanisms of ginsenosides will be discussed.

c-Jun, at the crossroad of the signaling network

c-Jun,the most extensively studied protein of the activator protein-1(AP-1)complex,is involved in numerous cell activities,such as proliferation,apoptosis,survival,tumorigenesis and tissue morphogenesis.Earlier studies focused on the structure and function have led to the identification of c-Jun as a basic leucine zipper(bZIP)transcription factor that acts as homo-or heterodimer,binding to DNA and regulating gene transcription.Later on,it was shown that extracellular signals can induce post-translational modifications of c-Jun,resulting in altered transcriptional activity and target gene expression.More recent work has uncovered multiple layers of a complex regulatory scheme in which c-Jun is able to crosstalk,amplify and integrate different signals for tissue development and disease.One example of such scheme is the autocrine amplification loop,in which signal-induced AP-1 activates the c-Jun gene promoter,while increased c-Jun expression feedbacks to potentiate AP-1 activity.Another example of such scheme,based on recent characterization of gene knockout mice,is that c-Jun integrates signals of several developmental pathways,including EGFR-ERK,EGFR-RhoA-ROCK,and activin B-MAP3K1-JNK for embryonic eyelid closure.After more than two decades of extensive research,c-Jun remains at the center stage of a molecular network with mysterious functional properties,some of which are yet to be discovered.In this article,we will provide a brief historical overview of studies on c-Jun regulation and function,and use eyelid development as an example to illustrate the complexity of c-Jun crosstalking with signaling pathways.

Glycyrrhizic acid activates chicken macrophages and enhances their Salmonella-killing capacity in vitro

Objective： Salmonella enterica remains a major cause of food-borne disease in humans, and Salmonella Typhimurium （ST） contamination of poultry products is a worldwide problem. Since macrophages play an essential role in controlling Salmonella infection, the aim of this study was to evaluate the effect of glycyrrhizic acid （GA） on immune function of chicken HD11 macrophages. Methods： Chicken HD11 macrophages were treated with GA （0, 12.5 25, 50, 100, 200, 400, or 800 pg/ml） and lipopolysaccharide （LPS, 500 ng/ml） for 3, 6, 12, 24, or 48 h. Evaluated responses included phagocytosis, bacteria-killing, gene expression of cell surface molecules （cluster of differentiation 40 （CD40）, CD80, CD83, and CD197） and antimicrobial effectors （inducible nitric oxide synthase （iNOS）, NADPH oxidase-1 （NOX-1）, interferon-γ （IFN-γ）, LPS-induced tumor necrosis factor （TNF）-α factor （LITAF）, interleukin-6 （IL-6） and IL-IO）, and production of nitric oxide （NO） and hydrogen peroxide （H202）. Results： GA increased the internalization of both fiuorescein isothiocyanate （FITC）-dextran and ST by HD11 cells and markedly decreased the intracellular survival of ST. We found that the messenger RNA （mRNA） expression of cell surface molecules （CD40, CDSO, CD83, and CD197） and cytokines （IFN-γ, IL-6, and IL-10） of HD11 cells was up-regulated following GA exposure. The expression of iNOS and NOX-1 was induced by GA and thereby the productions of NO and H202 in HD11 cells were enhanced. Notably, it was verified that nuclear factor-κB （NF-κB） and c-Jun N-terminal kinase （JNK） pathways were responsible for GA-induced synthesis of NO and IFN-γ gene expression. Conclusions： Taken together, these results suggested that GA exhibits a potent immune regulatory effect to activate chicken macrophages and enhances Salmonella-killing capacity.

Efficacy of decoction from Jieduan Niwan formula on rat model of acute-on-chronic liver failure induced by porcine serum

OBJECTIVE:To dynamically observe the efficacy of Jieduan Niwan formula(JDNW)on a rat model of acute-on-chronic liver failure(ACLF).METHODS:Seventy Wistar rats were divided into control group(6 rats),model group(22 rats),JDNW group(21 rats),and SP600125 group(21 rats).13 weeks'porcine serum injection followed with D-galactosamine and lipopolysaccharide joint acute attack was used to establish ACLF model.Rats in JDNW group were orally given JDNW formula for 3 days before acute attack;rats in SP600125 group were injected with SP60012530 min ahead of acute attack.Rats were sacrificed respectively at 4,8 and 12 h after model established.Alanine aminotransferase(ALT),aspartate aminotransferase(AST),total bilirubin(TBIL),Creatinine(CR),blood urea nitrogen(BUN),prothrombin activity(PTA)were examined by biochemical process,Tumor necrosis factor-alpha(TNF-α),interleukin-1β(IL-1β),interleukin-6(IL-6),interleukin-10(IL-10),transformed growth factor-beta 1(TGF-β1),High mobility group box-1(HMGB-1),CD3,CD4,CD8 were analyzed by enzyme-linked immunosorbent assay,apoptotic index(AI)was detected by terminal-deoxynucleoitidyl transferase mediated nick end labeling staining,expression of Bad,phosphorylated Jun N-terminal kinases(p-JNK)and Cytochrome C(Cyt C)were detected by immunohistochemical analysis,Bax and Bid were detected by Western blot analysis.RESULTS:In model group,the levels of ALT,AST,TBIL,CR,BUN,IL-1β,IL-6,IL-10,TGF-β1 and HMGB-1 remarkably increased and PTA decreased compared with control group(P<0.05),as time goes on,ALT,AST,TBIL,CR,BUN,continued to grow,while IL-1β,IL-6,IL-10,HMGB-1,TGF-β1 and PTA gradually decreased;massive necrosis could be seen;the levels of TNF-α,CD3,CD4,CD8,AI,p-JNK,Bax,Bad,Bid and Cyt C increased at 4 h and peaked at 8 h,but decreased at 12 h(P<0.05).JDNW group,by contrast,showed less pathological injury,increased PTA level,and reduced ALT,AST,TBIL,TNF-α,IL-1β,IL-6,IL-10,TGF-β1,HMGB-1,CD3,CD4 and CD8 levels(P<0.05),moreover,the AI and expression of p-JNK,Bax,Bad,Bid and Cyt C were lower than model group at 4 and 8 h but were higher at 12 h(P<0.05).Similar results were observed in SP600125 group.CONCLUSION:An ACLF rat model with low mortality can be established by porcine serum joint with D-galactosamine+lipopolysaccharide induction;JDNW decoction can effectively suppress the inflammatory reaction,improve the immune system,and protect the liver of ACLF rats,the mechanism might involve the inhibition of the JNK-induced mitochondrial apoptotic pathway.

Hydroxychavicol,a polyphenol from Piper betle leaf extract,induces cell cycle arrest and apoptosis in TP53-resistant HT-29 colon cancer cells

This study aims to elucidate the antiproliferative mechanism of hydroxychavicol(HC).Its effects on cell cycle,apoptosis,and the expression of c-Jun N-terminal kinase(JNK)and P38 mitogen-activated protein kinase(MAPK)in HT-29 colon cancer cells were investigated.HC was isolated from Piper betle leaf(PBL)and verified by high-performance liquid chromatography(HPLC),nuclear magnetic resonance(NMR),and gas chromatography-mass spectrometry(GC-MS).The cytotoxic effects of the standard drug 5-fluorouracil(5-FU),PBL water extract,and HC on HT-29 cells were measured after 24,48,and 72 h of treatment.Cell cycle and apoptosis modulation by 5-FU and HC treatments were investigated up to 30 h.Changes in phosphorylated JNK(pJNK)and P38(pP38)MAPK expression were observed up to 18 h.The half maximal inhibitory concentration(IC_(50))values of HC(30μg/mL)and PBL water extract(380μg/mL)were achieved at 24 h,whereas the IC_(50)of 5-FU(50μmol/L)was obtained at 72 h.Cell cycle arrest at the G0/G1 phase in HC-treated cells was observed from12 h onwards.Higher apoptotic cell death in HC-treated cells compared to 5-FU-treated cells(P<0.05)was observed.High expression of pJNK and pP38 MAPK was observed at 12 h in HC-treated cells,but not in 5-FU-treated HT-29 cells(P<0.05).It is concluded that HC induces cell cycle arrest and apoptosis of HT-29 cells,with these actions possibly mediated by JNK and P38 MAPK.

Mitochondrial damage and biogenesis in acetaminophen-induced liver injury

Liver injury and acute liver failure caused by acetaminophen(APAP)overdose is the clinically most important drug toxicity in Western countries.Mechanistic investigations have revealed a central role of mitochondria in the pathophysiology.Excess formation of the reactive metabolite N-acetyl-p-benzoquinone imine(NAPQI)after an overdose leads to hepatic glutathione depletion,mitochondrial protein adducts formation and an initial oxidant stress,which triggers the activation of mitogen activated protein(MAP)kinase cascade ultimately leading to c-jun N-terminal kinase(JNK)phosphorylation.Phospho-JNK translocates to the mitochondria and amplifies the oxidative and nitrosative stress eventually causing the mitochondrial membrane permeability transition pore opening and cessation of adenosine triphosphate(ATP)synthesis.In addition,mitochondrial matrix swelling ruptures the outer membrane and releases endonucleases,which cause nuclear deoxyribonucleic acid(DNA)fragmentation.Together,the nuclear DNA damage and the extensive mitochondrial dysfunction result in necrotic cell death.However,the procell death signaling events are counteracted by adaptive responses such as autophagy and mitochondrial biogenesis.The improved mechanistic insight into the pathophysiology leads to better understanding of the mechanisms of action of the existing antidote N-acetylcysteine and justifies the clinical testing of novel therapeutics such as 4-methylpyrazole and calmangafodipir.

Abnormal expression of TFIIIB subunits and RNA PolⅢgenes is associated with hepatocellular carcinoma

The levels of the products of RNA polymeraseⅢ-dependent genes(PolⅢgenes),including tRNAs and 5S rRNA,are elevated in transformed and tumor cells,which potentiate tumorigenesis.TFIIB-related factor 1(Brf1)is a key transcription factor and specifically regulates the transcription of PolⅢgenes.In vivo and in vitro studies have demonstrated that a decrease in Brf1 reduces PolⅢgene transcription and is sufficient for inhibiting cell transformation and tumor formation.Emerging evidence indicates that dysregulation of Brf1 and PolⅢgenes is linked to the development of hepatocellular carcinoma(HCC)in humans and animals.We have reported that Brf1 is overexpressed in human liver cancer patients and that those with high Brf1 levels have shorter survivals.This review summarizes the effects of dysregulation of these genes on HCC and their regulation by signaling pathways and epigenetics.These novel data should help us determine the molecular mechanisms of HCC from a different perspective and guide the development of therapeutic approaches for HCC patients.