Activator protein-1 involved in growth inhibition by RASSF1A gene in the human gastric carcinoma cell line SGC7901

AIM:To investigate the role of Ras association domain family protein 1 isoform A (RASSF1A) in gastric tumorigenesis. METHODS:Through over-expression of RASSF1A gene in the SGC7901 cell line which was induced by a lipofectamine-mediated gene transfer approach. Activator protein-1 (AP-1) DNA binding activity was measured by electrophoretic mobility shift assay (EMSA). RESULTS:Compared with the control clones, cells over- expressing RASSF1A exhibited significant inhibition of cell growth with G1 cell cycle arrest in vitro and in vivo. The over-expression of RASSF1A significantly inhibited AP-1 activity in SGC7901 cells (0.981±0.011 vs 0.354±0.053, P<0.001). In addition, both Western blot analysis and immunocytochemistry demonstrated that RASSF1A down-regulated the expression of c-Fos (0.975± 0.02 vs 0.095±0.024, P<0.001) but not c-Jun. CONCLUSION: Over-expression of RASSF1A inhibits the growth of SGC7901 cells by negatively regulating the AP-1 activity, the latter in turn negatively signals cell proliferation.

Role of Activator Protein-1 in the Transcription of Interleukin-5 Gene Regulated by Protein Kinase C Signal in Asthmatic Human TLymphocytes

Summary: In order to explore the role of activator protein-1 (AP-1) in the transcription of interleukin-5 (IL-5) gene regulated by protein kinase C (PKC) signal in peripheral blood T lymphocytes from asthmatic patient, T lymphocytes were isolated and purified from peripheral blood of each asthmatic patient. The T lymphocytes were randomly divided into 4 groups: group A (blank control), group B (treated with PKC agonist phorbol 12-myristate 13-acetate (PMA)), Group C (treated with PMA and AP-1 cis-element decoy oligodeoxynucleotides (decoy ODNs)), and group D (treated with PMA and AP-1 mutant decoy ODNs). The ODNs were transfected into the T cells of group C and D by cation liposome respectively. Reverse transcription-polymerase chain reaction (RT-PCR) was employed to assess IL-5 mRNA expression, and electrophoretic mobility shift assays (EMSA) for the activation of AP-1. The results showed that the activation of AP-1 (88 003.58±1 626.57) and the expression of IL-5 mRNA (0.8300±0.0294) in T lymphocytes stimulated with PMA were significantly higher than these in blank control (20 888.47±1103.56 and 0.3050±0.0208, respectively, P< 0.01), while the indexes (23 219.83±1 024.86 and 0.3425±0.0171 respectively) of T lymphocytes stimulated with PMA and AP-1 decoy ODNs were significantly inhibited, as compared with group B (P< 0.01). The indexes (87 107.41±1 342.92 and 0.8225±0.0222, respectively) in T lymphocytes stimulated with PMA and AP-1 mutant decoy ODNs did not exhibit significant changes, as compared with group B (P>0.05). The significant positive correlation was found between the activation of AP-1 and the expression of IL-5 mRNA (P< 0.01). It was concluded that AP-1 might participate in the signal transduction of PKC-triggered transcription of IL-5 gene in asthmatic T lymphocytes. This suggests the activation of PKC/AP-1 signal transduction cascade of T lymphocytes may play an important role in the pathogenesis of asthma.

All-trans Retinoic Acid Diminishes Collagen Production in a Hepatic Stellate Cell Line via Suppression of Active Protein-1 and c-Jun N-terminal Kinase Signal

Following acute and chronic liver injury,hepatic stellate cells (HSCs) become activated to undergo a phenotypic transformation into myofibroblast-like cells and lose their retinol content,but the mechanisms of retinoid loss and its potential roles in HSCs activation and liver fibrosis are not understood.The influence of retinoids on HSCs and hepatic fibrosis remains controversial.The purpose of this study was to evaluate the effects of all-trans retinoid acid (ATRA) on cell proliferation,mRNA expression of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)],profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),fibrolytic genes (MMP-3,MMP-13) and the upstream element (JNK and AP-1) in the rat hepatic stellate cell line (CFSC-2G).Cell proliferation was evaluated by measuring BrdU incorporation.The mRNA expression levels of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)],profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and fibrolytic genes (MMP-3,MMP-13) were quantitatively detected by using real-time PCR.The mRNA expression of JNK and AP-1 was quantified by RT-PCR.The results showed that ATRA inhibited HSCs proliferation and diminished the mRNA expression of collagen genes [procollagen α1 (Ⅰ),procollagen α1 (Ⅲ)] and profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and significantly stimulated the mRNA expression of MMP-3 and MMP-13 in HSCs by suppressing the mRNA expression of JNK and AP-1.These findings suggested that ATRA could inhibit proliferation and collagen production of HSCs via the suppression of active protein-1 and c-Jun N-terminal kinase signal,then decrease the mRNAs expression of profibrogenic genes (TGF-β 1,CTGF,MMP-2,TIMP-1,TIMP-2,PAI-1),and significantly induce the mRNA expression of MMP-3 and MMP-13.

Reactive oxygen species-induced activation of Yes-associated protein-1 through the c-Myc pathway is a therapeutic target in hepatocellular carcinoma

BACKGROUND The Hippo signaling pathway regulates organ size by regulating cell proliferation and apoptosis with terminal effectors including Yes-associated protein-1(YAP-1).Dysregulation in Hippo pathway has been proposed as one of the therapeutic targets in hepatocarcinogenesis.The levels of reactive oxygen species(ROS)increase during the progression from early to advanced hepatocellular carcinoma(HCC).AIM To study the activation of YAP-1 by ROS-induced damage in HCC and the involved signaling pathway.METHODS The expression of YAP-1 in HCC cells(Huh-7,HepG2,and SNU-761)was quantified using real-time polymerase chain reaction and immunoblotting.Human HCC cells were treated with H2O2,which is a major component of ROS in living organisms,and with either YAP-1 small interfering RNA(siRNA)or control siRNA.To investigate the role of YAP-1 in HCC cells under oxidative stress,MTS assays were performed.Immunoblotting was performed to evaluate the signaling pathway responsible for the activation of YAP-1.Eighty-eight surgically resected frozen HCC tissue samples and 88 nontumor liver tissue samples were used for gene expression analyses.RESULTS H2O2 treatment increased the mRNA and protein expression of YAP-1 in HCC cells(Huh-7,HepG2,and SNU-761).Suppression of YAP-1 using siRNA transfection resulted in a significant decrease in tumor proliferation during H2O2 treatment both in vitro and in vivo(both P<0.05).The oncogenic action of YAP-1 occurred via the activation of the c-Myc pathway,leading to the upregulation of components of the unfolded protein response(UPR),including 78-kDa glucoseregulated protein and activating transcription factor-6(ATF-6).The YAP-1 mRNA levels in human HCC tissues were upregulated by 2.6-fold compared with those in nontumor tissues(P<0.05)and were positively correlated with the ATF-6 Levels(Pearson’s coefficient=0.299;P<0.05).CONCLUSION This study shows a novel connection between YAP-1 and the UPR through the c-Myc pathway during oxidative stress in HCC.The ROS-induced activation of YAP-1 via the c-Myc pathway,which leads to the activation of the UPR pathway,might be a therapeutic target in HCC.

AP-1 and SP1 trans-activate the expression of hepatic CYP1A1 and CYP2A6 in the bioactivation of AFB1 in chicken

Dietary exposure to aflatoxin B1(AFB1)is harmful to the health and performance of domestic animals.The hepatic cytochrome P450s(CYPs),CYP1A1 and CYP2A6,are the primary enzymes responsible for the bioactivation of AFB1to the highly toxic exo-AFB1-8,9-epoxide(AFBO)in chicks.However,the transcriptional regulation mechanism of these CYP genes in the liver of chicks in AFB1metabolism remains unknown.Dual-luciferase reporter assay,bioinformatics and site-directed mutation results indicated that specificity protein 1(SP1)and activator protein-1(AP-1)motifs were located in the core region-1,063/-948,-606/-541 of the CYP1A1 promoter as well as-636/-595,-503/-462,-147/-1 of the CYP2A6 promoter.Furthermore,overexpression and decoy oligodeoxynucleotide technologies demonstrated that SP1 and AP-1 were pivotal transcriptional activators regulating the promoter activity of CYP1A1 and CYP2A6.Moreover,bioactivation of AFB1to AFBO could be increased by upregulation of CYP1A1 and CYP2A6 expression,which was trans-activated owing to the upregulation of AP-1,rather than SP1,stimulated by AFB1-induced reactive oxygen species.Additionally,nano-selenium could reduce ROS,downregulate AP-1 expression and then decrease the expression of CYP1A1 and CYP2A6,thus alleviating the toxicity of AFB1.In conclusion,AP-1 and SP1 played important roles in the transactivation of CYP1A1 and CYP2A6 expression and further bioactivated AFB1to AFBO in chicken liver,which could provide novel targets for the remediation of aflatoxicosis in chicks.

Effect of short- and long-term immunization of recombinant disorganized muscle protein-1(rDIM-1) against human filarial parasite Brugia malayi in rodents

Objective: To evaluate the effect of short-term and long-term immunization of recombinant disorganized muscle protein-1(r DIM-1) in rodents against human filarial parasite Brugia malayi.Methods: Recombinant Brugia malayi DIM-1(rDIM-1 bm) protein was cloned, expressed and purified using a Ni-NTA affinity column. Mastomys coucha were immunized with rDIM-1 bm in three immunization schedules: short-term(3-dose of rDIM-1 bm), and long-term(booster doses till 3-and 6-week) and subsequently challenged with infective third-stage larvae of filarial parasite Brugia malayi(L3). Microfilaraemia was monitored in L3 exposed groups on day 90 post larval inoculation(p.l.i.) and continued till day 205 p.l.i. On day 205 p.l.i. all the infected animals were killed and total worm burden was estimated. Cellular proliferative response, macrophage activity, nitric oxide(NO) release, specific IgG and its subtypes, IgE, IgA and Th1(IFN-γ, TNF-ααand IL-2) and Th2(IL-4, IL-5, IL-6, IL-10 and IL-13) cytokine release were determined. Results: Of the 3 different immunization schedules, shortterm immunization(3-dose schedule) showed better reduction in microfilarial burden(36%-63%) in the peripheral circulation, adult worm load(52%), whereas long-term immunization(3-and 6-week schedule) exerted less effect on peripheral microfilariae count(9%-58%), and adult worm burden(9%-12.5%). Short-term immunization resulted in upregulation of cellular proliferation, macrophages activity, NO release, specific IgG, IgG1, IgG2 a, Ig G2 b, IgE and IgA levels and both Th1(IFN-γ, TNF-α and IL-2) and Th2(IL-4, IL-5, IL-6, IL-10 and IL-13) cytokine release whereas long-term immunization(3-and 6-week schedule) exerted less effect on parasite burden and showed mixed immunological responses. None of the rDIM-1 bm administration schedules induced any pathology in lymphoid tissues, or alteration in mast cell number and granularity. Conclusions: The short-term immunization with rDIM-1 bm(3-dose schedule) induces robust immune responses and protects the host from filarial parasite infection.

3D-QSAR and action mechanism of potential dual inhibitors towards AP-1 and NF-κB

Three-dimensional quantitative structure-activity relationship （3D-QSAR） and docking studies of a series of novel dioxopyrrolinyl-amino-pyrimidine derivatives, which are potential dual inhibitors mediating a transcriptional activation towards protein-1 （AP-1） and nuclear factor kappa B （NF-κB）, have been carried out. The QS, AR models established by comparative molecular field analysis （CoMFA） and comparative molecular similarity index analysis （CoMSIA） show a good predictive ability with cross-validated coefficients q2 of 0.644 and 0.636, respectively. The docking result shows that there are quite lower average values of the flexible and rigid energy scores on the selected binding sites, meanwhile, it further shows that the binding sites just fall on the joint regions between AP-1 （and NF-κB） and DNA. The reason that these analogues have inhibition function towards AP-I and NF-κB is that their existence on these joint regions can effectively prevent free AP-I and NF-κB from binding to DNA. These results can offer a valuable theoretical reference to the pharmaceutical molecular design as well as the action mechanism analysis.

The Protective Effect of CoQ10 on ox-LDL——induced HUVEC Injury by AP-1 and PON2

[Objectives] To explore the protective effect and possible mechanisms of the coenzyme Q10( CoQ 10) on the human umbilical vein endothelial cell( HUVEC) injury induced by the oxidized low-density lipoprotein( ox-LDL). [Methods]With the human umbilical vein endothelial cells( HUVECs) cultured in vitro as the test target,the HUVECs were randomly divided into 5 groups: normal control group; model group; low concentration CoQ10 group( 12. 5); medium concentration CoQ10 group( 25); high concentration CoQ10 group( 50). The CCK-8 method was used to test the cell viability,and the drug concentration was screened in 60 μM of CoQ 10 toxic concentration; the total protein was extracted and Western blot was used to detect the protein expression of c-fos,c-jun and PON2; the RT-PCR method was used for determination of the content of c-fos,c-jun and PON2 mRNA. [Results]Compared with the normal group,the cell viability was significantly reduced in the 35 μg/m L high ox-LDL model group,and the cell injury was induced; compared with model group,after 12 h pre-protection,12. 5 μM,25 μM,50 μM CoQ10 could all significantly improve the survival of injured cells( P < 0. 05); compared with the normal group;the protein and mRNA levels of c-fos,c-jun,PON2 in the model group all declined; compared with the model group,the protein level and mRNA expression of c-fos,c-jun,PON2 in different CoQ10 groups increased to varying degrees( P < 0. 05). [Conclusions] CoQ 10 could reduce the HUVEC injury induced by high ox-LDL,and possible mechanism was achieved by upregulating the expression of AP-1 and PON2.

Efficacy of recombinant human osteoprotegerin combined with tinidazole in the treatment of periodontitis mice and its correlation with serum RANKL and MCP-1 levels

Objective: To investigate the effect of recombinant human osteoprotegerin combined with tinidazole on mice with periodontitis and the effect on serum RANKL and MCP-1 levels. Methods: 80 SPF-cleaned mice were randomly divided into 4 groups, 20 each, model group, tinidazole group and recombinant human osteoprotegerin group were modeled by Kimura et al., and tinidazole group received tinidazole. After intragastric administration, the recombinant human osteoprotegerin group was injected with recombinant human osteoprotegerin in the periodontal pocket according to the tinidazole group. The periodontal changes of the four groups of mice were observed and recorded, and the gingival rating was performed. Epithelial tissue morphology was observed by hematoxylin-eosin (HE) staining. Serum levels of IL-4, IL-6, RANKL and MCP-1 were measured by enzyme-linked immunosorbent assay. Results:After the intervention, the model group developed severe inflammatory reactions, including redness, hemorrhage, and deep periodontal pockets. The teeth were significantly loosened. The mice in the tinidazole group and the recombinant human osteoprotegerin group recovered substantially, and the gingival rating of the recombinant human osteoprotegerin group was better than that. The tinidazole group and the model group (P<0.05). The results of HE staining showed that the model group had edema, vasodilation and a large amount of inflammatory infiltration. The epithelial structure of the mice in the tinidazole group and the recombinant human osteoprotegerin group was intact and arranged closely and orderly. After intervention, the IL-4 in the tinidazole group and the recombinant human osteoprotegerin group was significantly higher than the model group and IL-6 was significantly lower than the model group (P<0.05), and the recombinant human osteoprotegerin group IL-4 was significantly higher after the intervention. IL-6 was significantly lower in the tinidazole group than in the tinidazole group (P<0.05). After the intervention, the tinidazole group and the recombinant human osteoprotegerin group were significantly reduced, and the recombinant human osteoprotegerin group RAKNL and MCP-1 were significantly lower than the model group (P>0.05). Conclusion: Recombinant human osteoprotegerin combined with tinidazole has a better therapeutic effect on gums and teeth in mice with periodontitis, and can lower the levels of RAKNL and MCP-1 in serum, inhibit bone resorption and protect teeth.

Retinoic acid receptor β is required for anti-activator protein-1 activity by retinoic acid in gastric cancer cells

Objective To investigate the role of retinoic acid receptor β (RARβ) in mediating inhibitory effect of all-trans retinoic acid (ATRA) on activator protein-1 (AP-1) activity in gastric cancer cells. Methods Transient transfection and chloramphenicol acetyltransferase (CAT) assay, Northern blot, gene transfection, 3-[4,5-dimethylthiazol-2-yl]-2,5-diphenyltetrazolium bromide (MTT) assay, and anchorage-independent growth assay were used.Results Transient transfection of RARβ expression vector into MKN-45 cells resulted in the RARβ concentration-dependent repression of AP-1 activity induced by 12-o-tetradecanoylphorbol-13-acetate (TPA), regardless of the presence of ATRA. When the c-jun and c-fos expression vectors were cotransfected with the RARβ expression vector into MKN-45 cells, AP-1 activity was also obviously repressed. The inhibitory effect, again, was RARβ-concentration-dependent. The stable transfection of the RARβ gene into MKN-45 cells led to cell growth inhibition and colony formation inhibition by ATRA. Furthermore, Cotransfection of both RARβ/DNA binding domain (DBD) and reporter gene could not alter AP-1 activity, even in the presence of ATRA. However, when the cotransfection was substituted with the RARβ/ligand binding domain (LBD), the inhibition was significantly enhanced by ATRA. Conclusion RARβ might be required for anti-AP-1 activity, and contribute to growth inhibition of gastric cancer cells by ATRA.

Synthesis and Expression in Escherichia coli of a Human Neutrophil Activating Protein-1/Interleukin-8 Gene

The complete gene coding for human neutrophilactivating protein-1/interleukin-8 was synthesized using a semi-chemical semi-enzymatic method. The synthetic gene was then overexpressed in Escherichia coli under the temperature-regulated control of the P_RP_L tandem promoters. As determined by SDS-PAGE and densitometry, the overexpressed protein comprised up to 18.5% and 10.9% of the total soluble protein in E. coli cells grown in shake flasks and in batch fermentation, respectively. The recombinant NAP-1/IL-8 was then purified to>95% homogeneity by gel filtration and cation exchange chromatography. The purified protein appeared as a single band on the SDS-PAGE gel and possessed potent chemotactic activity in the concentration of <10 ng/ml, as assayed by the agarose plate method. An early skin reactivity was also observed when the pure NAP-1/IL-8 was injected subcutaneously into the rabbits. The N-terminal 36 amino acid sequence of the recombinant NAP1/IL-8 was determined using the Edman method and was shown to be identical to that of the ntive protein.

AP-1 mediated signal transduction in thrombin induced regulation of PAL-1 expression in human mesangial cells

Objective To evaluate activator protein 1(AP 1) mediated mechanisms in thrombin induced qlasmino^gen activator inhibitor 1 (PAI 1) expression in cultured human glomerular mesangial cells (MCs) Methods Electrophoretic mobility shift assay (EMSA) was employed to assess AP 1 DNA binding activity, and Western blot hybridization was used for quantification of c fos and c jun, two subunits of AP 1 dimers PAI 1 activity and mRNA expression were analysed by the fibrin plate assay and Northern hybridization, respectively Results Thrombin concentration enhanced PAI 1 activity in the supernatant and stimulated PAI 1 mRNA expression in cultured MCs PAI 1 activity was blocked by hirudin, a specific inhibitor of thrombin Further study demonstrated that thrombin promoted AP 1 DNA binding activity but exerted little effect on c fos or c jun Curcumin (AP 1 inhibitor), staurosporine (PKC inhibitor), and genistein (PTK inhibitor) all reduced AP 1 mediated PAI 1 mRNA expression induced by thrombin in cultured MCs Conclusion The present study indicates that in cultured human MCs, thrombin stimulates PAI 1 expression through an AP 1 signal pathway, which may be mediated by PKC and PTK

Dihydroartemisinin beneficially regulates splenic immune cell heterogeneity through the SOD3-JNK-AP-1 axis

The immunomodulatory potential of dihydroartemisinin(DHA) has recently been highlighted;however, the potential mechanism remains to be clarified. Single-cell RNA sequencing was explored in combination with cellular and biochemical approaches to elucidate the immunomodulatory mechanisms of DHA. In this study, we found that DHA induced both spleen enlargement and rearrangement of splenic immune cell subsets in mice. It was revealed that DHA promoted the reversible expansion of effective regulatory T cells and interferon-γ^(+)cytotoxic CD8^(+)T cells in the spleen via induction of superoxide dismutase 3(SOD3) expression and increased phosphorylation of c-Jun N-terminal kinases(JNK) and its downstream activator protein 1(AP-1) transcription factors. Further, SOD3 knockout mice were resistant to the regulatory effect of DHA. Thus, DHA,through the activation of the SOD3-JNK-AP-1 axis, beneficially regulated immune cell heterogeneity and splenic immune cell homeostasis to treat autoimmune diseases.

Role of major adipokines in hypertension:A literature review

The incidence and prevalence of hypertension are increasing as a consequence of the obesity epidemic.Adipocytes and their variety of factors make contributions to the long-term regulation of blood pressure.The pathophysiologic states of hypertension,including obesity,are regulated by the production of adipocytederived factors.Increased body mass index was closely linked to elevated blood pressure.Mostly the hypertensive subjects were obese as well as overweight.There are numerous adipokines,however,this review article only focuses on the major adipokines including chemerin,visfatin,retinol-binding protein 4,plasminogen activator inhibitor-1,monocyte chemotactic protein-1,omentin-1,lipocalin-2,vaspin,progranulin,complement c1q tumor necrosis factor-related protein,and nesfatin-1 role in the pathogenesis of hypertension.This review article concludes the significant association of major adipokines in the pathogenesis of hypertensives.New research should be focused on other newly reported adipokine roles in hypertensive subjects and the management of these adipokines in hypertensive subjects.The discovery of this information could result in the creation of antihypertensive medications,particularly those that focus on obesity-related hypertension.

Benzydamine inhibits osteoclast differentiation and bone resorption via down-regulation of interleukin-1β expression

Bone diseases such as osteoporosis and periodontitis are induced by excessive osteoclastic activity,which is closely associated with inflammation.Benzydamine(BA)has been used as a cytokine-suppressive or non-steroidal anti-inflammatory drug that inhibits the production of proinflammatory cytokines or prostaglandins.However,its role in osteoclast differentiation and function remains unknown.Here,we explored the role of BA in regulating osteoclast differentiation and elucidated the underlying mechanism.BA inhibited osteoclast differentiation and strongly suppressed interleukin-1β(IL-1β)production.BA inhibited osteoclast formation and bone resorption when added to bone marrowderived macrophages and differentiated osteoclasts,and the inhibitory effect was reversed by IL-1βtreatment.The reporter assay and the inhibitor study of IL-1βtranscription suggested that BA inhibited nuclear factor-κB and activator protein-1 by regulating IκB kinase,extracellular signal regulated kinase and P38,resulting in the down-regulation of IL-1βexpression.BA also promoted osteoblast differentiation.Furthermore,BA protected lipopolysaccharide-and ovariectomy-induced bone loss in mice,suggesting therapeutic potential against inflammation-induced bone diseases and postmenopausal osteoporosis.

Enhancive effect of N,N'-dinitrosopiperazine on inducing precancerous lesion on nasal and/or nasopharyngeal epithelia of TgN(p53mt-LMP1)/HT mice

Objective： To investigate the enhancive effect ofN, N′-dinitrosopiperazine （DNP） on induced carcinogenesis in nasal and/or nasopharyngeal epithelia among TgN（p53mt-LMP1）/HT transgenic mice to examine the underlying mechanism for the development of nasopharyngeal carcinoma （NPC）. Methods： TgN（p53mt-LMP1）/HT transgenic mice and the same strain of C57BL/6J wild-type mice both at the age of 5 months were randomly divided into 2 groups in parallel, respectively, i.e., TgN（p53mt-LMP1）/HT cancerous lesion-inducing group （T1）, TgN（p53mt-LMP1）/HT control group （TC）, C57BL/6J cancerous lesion-inducing group （CI）, and C57BL/6J control group （CC）. TI and CI mice were treated only with DNP for 16 weeks, twice each week, while TC and CC mice were given the same volume of saline as controls.At the end of treatment, animals were sacrificed to collect epithelial tissue samples from nasal cavity and nasopharynx for pathohistological evaluation by hacmatoxylin and eosin （HE） staining and for determination on the expression ofTRAF2, c-Jun, and p 16 by immunohistochemistry. Results： Atypical hyperplasia was more significant in the samples of TI than in those of TC, CI, and CC, with the rates of lesions being 90%, 10%, 0, and 0 （P〈0.01） respectively, though DNP was used alone in a much shortened inducing period at less dosage and without the use of carcinogenic promoter 12-0-tetradecanoylphorbol-13-acetate as usual. The expressions of tumor necrosis factor （TNF） receptor-associated factor 2 （TRAF2） and c-Jun in these samples were significantly up-regulated in TI （P〈0.0 I）, while tbe expression of p16 was significantly lower in TI than in the other groups （P〈0.01）. Conclusion： TgN（p53mt-LMPI）/HT mice hold inherited constitutional defect in immune surveillance function, which can be aggravated by environmental carcinogens, such as DNP used even though in a much less strength. The enhanced carcinogenesis-inducing effect of DNP on TgN（p53mt-LMP1）/HT mice should be closely associated with abnormal signaling of activator protein-1 （AP-1） pathway, especially up-regulated expressions of TRAF2 and c-Jun, and down-regulated expression of p l6.

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.

Pathophysiology of insulin resistance and steatosis in patients with chronic viral hepatitis

Chronic hepatitis due to any cause leads to cirrhosis and end-stage liver disease.A growing body of literature has also shown that fatty liver due to overweight or obesity is a leading cause of cirrhosis.Due to the obesity epidemic,fatty liver is now a significant problem in clinical practice.Steatosis has an impact on the acceleration of liver damage in patients with chronic hepatitis due to other causes.An association between hepatitis C virus (HCV) infection,steatosis and the onset of insulin resistance has been reported.Insulin resistance is one of the leading factors for severe fibrosis in chronic HCV infections.Moreover,hyperinsulinemia has a deleterious effect on the management of chronic HCV.Response to therapy is increased by decreasing insulin resistance by weight loss or the use of thiazolidenediones or metformin.The underlying mechanisms of this complex interaction are not fully understood.A direct cytopathic effect of HCV has been suggested.The genomic structure of HCV (suggesting that some viral sequences are involved in the intracellular accumulation of triglycerides),lipid metabolism,the molecular links between the HCV core protein and lipid droplets (the core protein of HCV and its transcriptional regulatory function which induce a triglyceride accumulation in hepatocytes) and increased neolipogenesis and inhibited fatty acid degradation in mitochondria have been investigated.

Human umbilical cord-derived mesenchymal stem cells promote repair of neonatal brain injury caused by hypoxia/ischemia in rats

Administration of human umbilical cord-derived mesenchymal stem cells(hUC-MSCs)is believed to be an effective method for treating neurodevelopmental disorde rs.In this study,we investigated the possibility of hUC-MSCs treatment of neonatal hypoxic/ischemic brain injury associated with maternal immune activation and the underlying mechanism.We established neonatal rat models of hypoxic/ischemic brain injury by exposing pregnant rats to lipopolysaccharide on day 16 or 17 of pregnancy.Rat offspring were intranasally administe red hUC-MSCs on postnatal day 14.We found that polypyrimidine tract-binding protein-1(PTBP-1)participated in the regulation of lipopolysaccharide-induced maternal immune activation,which led to neonatal hypoxic/ischemic brain injury.Intranasal delive ry of hUC-MSCs inhibited PTBP-1 expression,alleviated neonatal brain injury-related inflammation,and regulated the number and function of glial fibrillary acidic protein-positive astrocytes,there by promoting plastic regeneration of neurons and im p roving brain function.These findings suggest that hUC-MSCs can effectively promote the repair of neonatal hypoxic/ischemic brain injury related to maternal immune activation through inhibition of PTBP-1 expression and astrocyte activation.

Bioactive proteins in healthy pregnancies and preeclampsia： relevance to hypertension and proteinuria

Background Bioactive proteins, such as cytokines and chemokines, have not been systematically evaluated in healthy and preeclamptic pregnancies. We aimed to investigate the difference of these proteins between healthy and preeclamptic pregnancies in order to help clarify their potential roles in the pathogenesis of hypertension and proteinuria in preeclampsia. Methods Samples of amniotic fluid and maternal/umbilical cord blood were collected from normal pregnancies and women with preeclampsia for examination of bioactive proteins. Fifty-three pregnant women were enrolled in this study. Of them, 30 pregnant women were recruited as healthy controls, and 23 pregnant women were diagnosed with preeclampsia. An antibody array was used to screen for higher levels of cytokines and related proteins in amniotic fluid than in the blood samples, and these proteins were then selected for quantification by immunoassay. Results Interleukin-1 receptor 4, hepatocyte growth factor, and urokinase plasminogen activator receptor were significantly elevated in the blood of preec^ampsia patients. In particular, intedeukin-1 receptor 4 was 8-fold higher in preeclampsia patients than in the healthy pregnancies. Moreover, in cord blood samples hepatocyte growth factor and interleukin-8 were significantly higher in preeclampsia patients. Conclusions Because of the biologic activities, Interleukin-1 receptor 4, hepatocyte growth factor, urokinase plasminogen activator receptor and interleukin-8 in maternal and/or cord blood could play a role in the pathogenesis of hypertension and proteinuria in preeclampsia.