AP-1 DNA Binding Research Articles

Effect of diabetes blood-stasis syndrome and Xuefu Zhuyu decoction on ERK1/2-VEGF signal pathway in rat retina Müller cells.

This research was aimed to investigate whether diabetic blood-stasis syndrome had a relationship with ERK1/2-VEGF signaling pathway in rat retina Müller cells and Traditional Chinese Drugs designed for promoting blood circulation to remove blood stasis had effectiveness for diabetic retinopathy (DR) treatment. Immunofluorescence was applied to determine purity of Müller cells. Müller cells were stimulated by blood serum obtained from rats with blood-stasis syndrome and then treated by Xuefu Zhuyu decoction. Western blot analysis, RT-PCR and ELISA were used to measure the expression of VEGF. Western blot analysis was used to determine the phosphorylation of ERK1/2. The status of AP-1 DNA binding activity was monitored by electrophoretic mobility shift assay (EMSA). Stimulation of Müller cells by blood serum of rat with diabetic blood stasis increased the secretion of VEGF, activated ERK1/2 and AP-1 DNA-binding activity. And treatment of Xuefu Zhuyu decoction could weaken this phenomenon. What's more, ERK1/2 signaling pathway inhibitor U0126 also could inhibit the expression of VEGF. Diabetic blood-stasis syndrome in theory of traditional Chinese Medicine has positive role in regulating ERK1/2-VEGF signaling pathway. Traditional Chinese drugs for promoting blood circulation to remove blood stasis would be an effective therapy to treat DR.

Genome-Wide Analysis of the RAV Transcription Factor Genes in Rice Reveals Their Response Patterns to Hormones and Virus Infection.

The RAV family is part of the B3 superfamily and is one of the most abundant transcription factor families in plants. Members have highly conserved B3 or AP2 DNA binding domains. Although the RAV family genes of several species have been systematically identified from genome-wide studies, there has been no comprehensive study to identify rice RAV family genes. Here, we identified 15 genes of the RAV family in the rice genome and analyzed their phylogenetic relationships, gene structure, conserved domains, and chromosomal distribution. Based on domain similarity and phylogenetic topology, rice RAV transcription factors were phylogenetically clustered into four groups. qRT-PCR analyses showed that expression of these RAV genes was significantly up-regulated or down-regulated by plant hormone treatments, including BL, NAA, IAA, MeJA, and SA. Most of the rice RAV genes were dramatically down-regulated in response to rice stripe virus (RSV) and mostly up-regulated in response to Southern rice black-streaked dwarf virus (SRBSDV). These results suggest that the rice RAV genes are involved in diverse signaling pathways and in varied responses to virus infection.

AAV-mediated AP-1 decoy oligonucleotide expression inhibits aortic elastolysis in a mouse model of Marfan syndrome.

Marfan syndrome is one of the most common inherited disorders of connective tissue caused by fibrillin-1 mutations, characterized by enhanced transcription factor AP-1 DNA binding activity and subsequently abnormally increased expression and activity of matrix-metalloproteinases (MMPs). We aimed to establish a novel adeno-associated virus (AAV)-based strategy for long-term expression of an AP-1 neutralizing RNA hairpin (hp) decoy oligonucleotide (dON) in the aorta to prevent aortic elastolysis in a murine model of Marfan syndrome. Using fibrillin-1 hypomorphic mice (mgR/mgR), aortic grafts from young (9 weeks old) donor mgR/mgR mice were transduced ex vivo with AAV vectors and implanted as infrarenal aortic interposition grafts in mgR/mgR mice. Grafts were explanted after 30 days. For in vitro studies, isolated primary aortic smooth muscle cells (SMCs) from mgR/mgR mice were used. Elastica-van-Giesson staining visualized elastolysis, reactive oxygen species (ROS) production was assessed using dihydroethidine staining. RNA F.I.S.H. verified AP-1 hp dON generation in the ex vivo transduced aortic tissue. MMP expression and activity were assessed by western blotting and immunoprecipitation combined with zymography.Transduction resulted in stable therapeutic dON expression in endothelial and SMCs. MMP expression and activity, ROS formation as well as expression of monocyte chemoattractant protein-1 were significantly reduced. Monocyte graft infiltration declined and the integrity of the elastin architecture was maintained. RNAseq analysis confirmed the beneficial effect of AP-1 neutralization on the pro-inflammatory environment in SMCs. This novel approach protects from deterioration of aortic stability by sustained delivery of nucleic acids-based therapeutics and further elucidated how to interfere with the mechanism of elastolysis.

Constitutive activation of transcription factor AP-1 in primary adult T-cell leukemia cells

AbstractHuman T-cell leukemia virus type-I (HTLV-I) is the etiologic agent of adult T-cell leukemia (ATL). This study examined the status of the oncogenic transcription factor AP-1 in leukemic cells freshly isolated from patients with ATL. Leukemic cells from peripheral blood of all patients with ATL exhibited constitutive AP-1 DNA binding activity, whereas mononuclear cells from normal individuals did not. In agreement with previous studies, HTLV-I transforming protein, Tax, was found to stimulate the DNA binding activity of AP-1 in a T-cell line. However, HTLV-I genes, including Tax, were not significantly expressed in leukemic cells freshly obtained from patients with ATL. Moreover, all T-cell lines derived from leukemic cells of patients with ATL also displayed constitutive AP-1 DNA binding activity, but expressed little Tax protein. Thus, leukemic cells of patients with ATL appear to have Tax-independent mechanisms that induce AP-1 activity, both in vivo and in vitro. In antibody supershift experiments, AP-1 in fresh leukemic cells and ATL-derived cell lines were found to contain JunD. Consistently, all primary ATL cells and ATL-derived cell lines expressed high levels of JunD messenger RNA. Our results suggest that AP-1 is activated in leukemic cells of patients with ATL through a Tax-independent mechanism and this may play a role in the deregulated phenotypes of ATL leukemic cells.

Importin β1 regulates cell growth and survival during adult T cell leukemia/lymphoma therapy

There is no cure for adult T cell leukemia/lymphoma (ATLL) associated with human T cell leukemia virus type 1 (HTLV-1), and novel targeted strategies are needed. NF-κB and AP-1 are crucial for ATLL, and both are transported to the nucleus by an importin (IPO)α/β heterodimeric complex to activate target genes. In this study, we aimed to elucidate the function of IPOβ1 in ATLL. The expression of IPOβ1 was analyzed by western blotting and RT-PCR. Cell growth, viability, cell cycle, apoptosis and intracellular signaling cascades were examined by the water-soluble tetrazolium-8 assay, flow cytometry and western blotting. Xenograft tumors in severe combined immune deficient mice were used to evaluate the growth of ATLL cells in vivo. IPOβ1 was upregulated in HTLV-1-infected T cell lines. Further, IPOβ1 knockdown or the IPOβ1 inhibitor importazole and the IPOα/β1 inhibitor ivermectin reduced HTLV-1-infected T cell proliferation. However, the effect of inhibitors on uninfected T cells was less pronounced. Further, in HTLV-1-infected T cell lines, inhibitors suppressed NF-κB and AP-1 nuclear transport and DNA binding, induced apoptosis and poly (ADP-ribose) polymerase cleavage, and activated caspase-3, caspase-8 and caspase-9. Inhibitors also mediated G1 cell cycle arrest. Moreover, the expression of NF-κB- and AP-1-target proteins involved in cell cycle and apoptosis was reduced. In vivo, the IPOα/β1 inhibitor ivermectin decreased ATLL tumor burden without side effects. IPOβ1 mediated NF-κB and AP-1 translocation into ATLL cell nuclei, thereby regulating cell growth and survival, which provides new insights for targeted ATLL therapies. Thus, ivermectin, an anti-strongyloidiasis medication, could be a potent anti-ATLL agent.

Abstract B25: SMARCA4/BRG1 and AP-1 co-regulate an epithelial-like signature in small-cell carcinoma of ovary, hypercalcemic type (SCCOHT)

Abstract Mutations in SMARCA4 (BRG1), one of the two mutually exclusive ATPases of the SWI/SNF chromatin remodeling complex, occur in >95% of small cell carcinomas of the ovary, hypercalcemic type (SCCOHT), a rare and aggressive form of ovarian cancer. Because of its apparent role as a driver for SCCOHT, we performed integrative multi-omic analyses in a SCCOHT cell line +/- BRG1 re-expression to identify its role in SCCOHT tumorigenesis. After re-expression, BRG1 was recruited to both distal and promoter regions. We also observed increased chromatin accessibility at distal sites enriched for transcription factor binding motifs for AP-1 family members. Of interest, BRG1 re-expression induced an epithelial-like gene and protein expression concomitant with enrichment of AP-1 motifs at the TSS of highly upregulated epithelial genes. To determine the biologic relevance of these changes at AP-1 binding sites, we used a dominant negative AP-1 cell line to demonstrate that the necessity of AP-1 DNA binding activity and BRG1 re-expression for the protein expression of epithelial genes. Our study demonstrates that BRG1 loss may drive SCCOHT tumorigenesis by diminishing an epithelial-like gene and protein signature of its cell of origin driven by altered AP-1 binding. Citation Format: Krystal A. Orlando, Jesse R. Raab, Amber K. Douglas, Aierken Abudu, Yemin Wang, Gian Luca Negri, Shane Colborne, Gregg B. Morin, Jessica D. Lang, William P.D. Hendricks, Elizabeth A. Raupach, Patrick Pirrotte, David G. Huntsman, Jeffrey M. Trent, Joel S. Parker, Bernard E. Weissman. SMARCA4/BRG1 and AP-1 co-regulate an epithelial-like signature in small-cell carcinoma of ovary, hypercalcemic type (SCCOHT) [abstract]. In: Proceedings of the AACR Special Conference on Advances in Ovarian Cancer Research; 2019 Sep 13-16, 2019; Atlanta, GA. Philadelphia (PA): AACR; Clin Cancer Res 2020;26(13_Suppl):Abstract nr B25.

15d-PGJ2 inhibits NF-κB and AP-1-mediated MMP-9 expression and invasion of breast cancer cell by means of a heme oxygenase-1-dependent mechanism

Activation of peroxisome proliferator-activated receptor γ (PPARγ) serves as a key factor in the proliferation and invasion of breast cancer cells and is a potential therapeutic target for breast cancer. However, the mechanisms underlying this effect remain largely unknown. Heme oxygenase-1 (HO-1) is induced and over-expressed in various cancers and is associated with features of tumor aggressiveness. Recent studies have shown that HO-1 is a major downstream target of PPARγ. In this study, we investigated the effects of induction of HO-1 by PPARγ on TPA-induced MMP-9 expression and cell invasion using MCF-7 breast cancer cells. TPA treatment increased NF-μB /AP-1 DNA binding as well as MMP-9 expression. These effects were significantly blocked by 15d-PGJ2, a natural PPARγ ligand. 15d-PGJ2 induced HO-1 expression in a dose-dependent manner. Interestingly, HO-1 siRNA significantly attenuated the inhibition of TPA-induced MMP-9 protein expression and cell invasion by 15d-PGJ2. These results suggest that 15d-PGJ2 inhibits TPA-induced MMP-9 expression and invasion of MCF-7 cells by means of a heme oxygenase-1-dependent mechanism. Therefore, PPARγ/HO-1 signaling-pathway inhibition may be beneficial for prevention and treatment of breast cancer.

Simultaneous Mapping of Molecular Proximity and Comobility Reveals Agonist-Enhanced Dimerization and DNA Binding of Nuclear Receptors.

Single Plane Illumination Microscopy (SPIM) revolutionized time lapse imaging of live cells and organisms due to its high speed and reduced photodamage. Quantitative mapping of molecular (co)mobility by fluorescence (cross-)correlation spectroscopy (F(C)CS) in a SPIM has been introduced to reveal molecular diffusion and binding. A complementary aspect of interactions is proximity, which can be studied by Förster resonance energy transfer (FRET). Here, we extend SPIM-FCCS by alternating laser excitation, which reduces false positive cross-correlation and facilitates comapping of FRET. Thus, different aspects of interacting systems can be studied simultaneously, and molecular subpopulations can be discriminated by multiparameter analysis. After demonstrating the benefits of the method on the AP-1 transcription factor, the dimerization and DNA binding behavior of retinoic acid receptor (RAR) and retinoid X receptor (RXR) is revealed, and an extension of the molecular switch model of the nuclear receptor action is proposed. Our data imply that RAR agonist enhances RAR-RXR heterodimerization, and chromatin binding/dimerization are positively correlated. We also propose a ligand induced conformational change bringing the N-termini of RAR and RXR closer together. The RXR agonist increased homodimerization of RXR suggesting that RXR may act as an autonomous transcription factor.

Isolation and characterization of larch BABY BOOM2 and its regulation of adventitious root development

The BABY BOOM2 gene, designated LkBBM2, and its promoter were isolated from hybrid larch (Larix kaempferi × L. olgensis). The open reading frame of LkBBM2 was 2574 bp, encoding 857 amino acids. The LkBBM2 protein contains two AP2 DNA binding domains and a BBM specific motif, but lacks the euANT5 motif common to AP2 family members. The LkBBM2 promoter contains several hormone response and root-specific expression elements. LkBBM2 expression was significantly higher in larch adventitious roots (ARs) than in stems, leaves or stem tips, and increased after auxin treatment. The fused protein LkBBM2-GFP was localized in both the nucleus and cytoplasm whereas LkBBM1-GFP was only localized in the nucleus. Over-expression of LkBBM2 and LkBBM1 in Arabidopsis significantly elongated the roots. Furthermore, over-expression those two genes in the hybrid poplar (Populus alba × P. glandulosa) significantly increased ARs number. We speculated that these two genes regulate AR development.

Stimulation of TRPV1 channels activates the AP-1 transcription factor

Transient receptor potential vanilloid 1 (TRPV1) channels were originally described as the receptors of capsaicin, the main constituent of hot chili pepper. The biological functions of TRPV1 channels include pain sensation and inflammatory thermal hyperalgesia. Here, we show that stimulation of HEK293 cells expressing TRPV1 channels (H2C1 cells) with capsaicin or the TRPV1 ligand resiniferatoxin activated transcription mediated by the transcription factor AP-1. No cell death was occurring under these experimental conditions. The AP-1 activity was not altered in capsaicin or resiniferatoxin-stimulated HEK293 cells lacking TRPV1. We identified the AP-1 DNA binding site as the capsaicin/resiniferatoxin-responsive element. Stimulation with the TRPV1 ligand N-arachidonoyldopamine increased AP-1 activity in a TRPV1-dependent and TRPV1-independent manner. Stimulation of TRPV1 channels induced an influx of Ca2+ into the cells and this rise in intracellular Ca2+ was essential for activating AP-1 in capsaicin or resiniferatoxin-stimulated cells. N-arachidonoyldopamine stimulation induced a rise in intracellular Ca2+ in a TRPV-1 dependent and independent manner. AP-1 is a dimeric transcription factor, composed of proteins of the c-Jun, c-Fos and ATF families. Stimulation of TRPV1 channels with capsaicin increased c-Jun and c-Fos biosynthesis in H2C1 cells. The signal transduction of capsaicin, leading to enhanced AP-1-mediated transcription, required extracellular signal-regulated protein kinase ERK1/2 as a signal transducer and the activation of the transcription factors c-Jun and ternary complex factor. Together, these data suggest that the intracellular functions of TRPV1 stimulation may rely on the activation of a stimulus-regulated protein kinase and stimulus-responsive transcription factors.

Inhibition of early T cell cytokine production by arsenic trioxide occurs independently of Nrf2.

Nuclear factor erythroid 2-related factor 2 (Nrf2) is a stress-activated transcription factor that induces a variety of cytoprotective genes. Nrf2 also mediates immunosuppressive effects in multiple inflammatory models. Upon activation, Nrf2 dissociates from its repressor protein, Keap1, and translocates to the nucleus where it induces Nrf2 target genes. The Nrf2-Keap1 interaction is disrupted by the environmental toxicant and chemotherapeutic agent arsenic trioxide (ATO). The purpose of the present study was to determine the effects of ATO on early events of T cell activation and the role of Nrf2 in those effects. The Nrf2 target genes Hmox-1, Nqo-1, and Gclc were all upregulated by ATO (1–2 μM) in splenocytes derived from wild-type, but not Nrf2-null, mice, suggesting that Nrf2 is activated by ATO in splenocytes. ATO also inhibited IFNγ, IL-2, and GM-CSF mRNA and protein production in wild-type splenocytes activated with the T cell activator, anti-CD3/anti-CD28. However, ATO also decreased production of these cytokines in activated splenocytes from Nrf2-null mice, suggesting the inhibition is independent of Nrf2. Interestingly, ATO inhibited TNFα protein secretion, but not mRNA expression, in activated splenocytes suggesting the inhibition is due to post-transcriptional modification. In addition, c-Fos DNA binding was significantly diminished by ATO in wild-type and Nrf2-null splenocytes activated with anti-CD3/anti-CD28, consistent with the observed inhibition of cytokine production by ATO. Collectively, this study suggests that although ATO activates Nrf2 in splenocytes, inhibition of early T cell cytokine production by ATO occurs independently of Nrf2 and may instead be due to impaired AP-1 DNA binding.

Torilin Inhibits Inflammation by Limiting TAK1-Mediated MAP Kinase and NF-κB Activation.

Torilin, a sesquiterpene isolated from the fruits of Torilis japonica, has shown antimicrobial, anticancer, and anti-inflammatory properties. However, data on the mechanism of torilin action against inflammation is limited. This study aimed at determining the anti-inflammatory property of torilin in LPS-induced inflammation using in vitro model of inflammation. We examined torilin's effect on expression levels of inflammatory mediators and cytokines in LPS-stimulated RAW 264.7 macrophages. The involvement of NF-kB and AP-1, MAP kinases, and adaptor proteins were assessed. Torilin strongly inhibited LPS-induced NO release, iNOS, PGE2, COX-2, NF-α, IL-1β, IL-6, and GM-CSF gene and protein expressions. In addition, MAPKs were also suppressed by torilin pretreatment. Involvement of ERK1/2, P38MAPK, and JNK1/2 was further confirmed by PD98059, SB203580, and SP600125 mediated suppression of iNOS and COX-2 proteins. Furthermore, torilin attenuated NF-kB and AP-1 translocation, DNA binding, and reporter gene transcription. Interestingly, torilin inhibited TAK1 kinase activation with the subsequent suppression of MAPK-mediated JNK, p38, ERK1/2, and AP-1 (ATF-2 and c-jun) activation and IKK-mediated I-κBα degradation, p65/p50 activation, and translocation. Together, the results revealed the suppression of NF-κB and AP-1 regulated inflammatory mediator and cytokine expressions, suggesting the test compound's potential as a candidate anti-inflammatory agent.

Three Arachidonoylamide Derivatives Inhibit Pro-Inflammatory Genes Expression by Modulating NF-kB and AP1 Activities.

Since the anti-inflammatory activity of arachidonic acid derivatives was previously reported, we synthesized three new amide derivatives of arachidonic acid (AA-Ds) and tested their anti-inflammatory effects on an in vitro skin inflammation model. Aim of our study was to find derivatives of natural compounds able to down regulate inflammatory signal transduction pathway. Human keratinocytes cell line (HaCaT) was cultured and induced by cytokines in the presence of AA-Ds. Cytokines administration elicited an inflammatory response mediated by NF-kB and STAT-1 activation that induced proinflammatory genes expression. By real time PCR we found that 24 hours after induction all AA-Ds significantly inhibit inducible Nitric Oxide Synthase (iNOS), TNFα, Inhibitor α of NF-kB, chemokine (C-X-C motif) ligand 9 and 10 genes expression. We analyzed their molecular effects in particular on the iNOS gene expression. Since iNOS transcript half-life did not change with AA-Ds treatment, we excluded a prominent role of post-transcriptional regulation for this gene and focused our attention on its transcriptional regulation. Starting three-five hours after cytokines induction, HaCaT cells, pretreated with each compound, showed inhibition of both NF-kB DNA-binding and NF-kB p65-Ser536 phosphorylation. STAT1 activation was inhibited only by AA-D4 derivative. To explain why the inhibition of iNOS expression began late after induction we analyzed activities of others key transcription factors. AA-Ds treatment elicited early increases of AP1 DNA binding as well as c-Jun, c-Fos and Fra-1 mRNA levels. Our data agree with the repressing effects of AP1 on human iNOS promoter previously described in others cell systems (Kleinert et al.). AA-Ds shown to be good candidates as inhibitors of several pro-inflammatory genes induction and our study provides indications for their possible use as new antiinflammatory drugs.

Pseuderanthemum palatiferum leaf extract inhibits the proinflammatory cytokines, TNF-α and IL-6 expression in LPS-activated macrophages

The anti-inflammatory potential and underlying mechanisms of an ethanol extract of Pseuderanthemum palatiferum (EEP) leaves was investigated using LPS-activated macrophages. Our results show EEP produced a concentration-dependent suppression of TNF-α and IL-6 secretion by LPS-activated mouse peritoneal macrophages. EEP also suppressed LPS-induced TNF-α and IL-6 protein and mRNA levels in mouse-derived myeloid cell line RAW264.7. To further elucidate the molecular mechanisms responsible for impaired TNF-α and IL-6 regulation by EEP, the activation of transcription factors, NF-κB, C/EBP, and AP-1, was monitored using electrophoretic mobility shift assays. EEP suppressed LPS-induced NF-κB DNA binding activity within both the TNF-α and IL-6 promoters in RAW264.7 cells with impairment being more pronounced in the IL-6 promoter. In addition, EEP exhibited a concentration-dependent suppression of C/EBP and AP-1 DNA binding activity within the IL-6 promoter. Concordantly, IL-6 luciferase promoter reporter activity was also suppressed by EEP in transiently transfected RAW264.7 cells, upon LPS activation. EEP analysis by GC-MS and HPLC DAD-MSD revealed the presence of β-sitosterol and various polyphenols, respectively, which are known to possess anti-inflammatory activity. Collectively, these results suggest that the anti-inflammatory effects of EEP are mediated, at least in part, by modulating TNF-α and IL-6 expression through impairment of NF-κB, C/EBP, and AP-1 activity.

Gene sharing between Epstein-Barr virus and human immune response genes.

Epstein-Barr virus (also termed HHV-4, EBV), a component of the human virome or metagenome, is associated as a co-factor in many common human autoimmune diseases through epidemiologic evidence. Numerous EBV genes are functional as well as structural homologues of important immune response genes. For example, EBV-encoded BCRF1 is a functional homologue of IL-10, a critical cytokine regulator of immune tolerance. BZLF-1, an EBV-encoded transcription factor, contains regions with functional homology to both AP-1 and NF-κB DNA binding immune response regulatory factors. The author proposes a paradigm of "gene sharing" between viral- and host-encoded proteins as extension of molecular mimicry that has been largely overlooked in animal models that consider only host genomic factors rather than viral pathogens and the metagenome. Gene sharing may trigger chaotic behavior in human autoimmune disease through unstable feedback loops and perturbations of immune tolerance.

Expression and regulation of a cold-responsive gene,CsCBFinCitrus sinensis(L.) Osbeck under low temperature, high salinity and abscisic acid

CBF (C-Repeat/Dehydration-Responsive Element Binding Factor) as a transcription factor plays important roles in stress responses and stress-related regulatory network in plants. CsCBF, a CBF encoding gene in sweet orange (Citrus sinensis (L.) Osbeck) was isolated and investigated in expression profiles under abiotic stresses. Semi-quantitative RT-PCR analysis indicated that CsCBF expression was altered obviously in response to low temperature (4°C), high salinity (250 mM NaCl) and abscisic acid (100 μM ABA). To learn more information about CsCBF gene, genomic DNA and upstream regulatory sequence were sequenced definitely and analyzed with a series of bioinformatic tools. The results showed that there were no introns in CsCBF genomic DNA, and CBF signature sequences and AP2 DNA binding domain were also highly conserved in CsCBF amino acid sequence. In addition, more than one CBF protein was encoded in sweet orange genome. Promoter prediction analysis suggested that several stress-related cis-acting elements were detected in CsCBF regulatory region, such as MYB, MYC, ABRE, Circadian, et al.. Importantly, two putative induction regions of CBF expression, ICEr1 and ICEr2, were also found in an 85-bp section of CsCBF promoter, which may contribute to understanding of CBF transcriptional activation under stress.

Citrus bergamia Juice Extract Attenuates β-Amyloid-Induced Pro-Inflammatory Activation of THP-1 Cells Through MAPK and AP-1 Pathways.

Flavonoids have been shown to be effective in protecting against age-related cognitive and motor decline in both in vitro and in vivo models. Recently, a flavonoid-rich extract of Citrus bergamia juice (BJe) has been shown to display anti-oxidant and anti-inflammatory properties against LPS-induced activation of human THP-1 monocytes. In the light of these observations, we wondered whether BJe may be beneficial against neuroinflammatory processes, such as those observed in Alzheimer’s disease. To this aim we used THP-1 monocytes to investigate the mechanisms underlying the beneficial potential of BJe against amyloid-beta1–42 (Aβ1−42) -mediated inflammation. Exposure of THP-1 cells to Aβ1−42 significantly induced the expression and secretion of IL-6 and IL-1β in THP-1 cells and increased the phosphorylation of ERK 1/2 as well as p46 and p54 members of JNK family. Moreover, Aβ1−42 raises AP-1 DNA binding activity in THP-1-treated cells. Interestingly, all these effects were reduced in the presence of BJe. Our data indicate that BJe may effectively counteract the pro-inflammatory activation of monocytes/microglial cells exposed to amyloid fibrils, suggesting a promising role as a natural drug against neuroinflammatory processes.

AP-1 transcription factor mediates VEGF-induced endothelial cell migration and proliferation

VEGF, upon binding to its endothelial cell specific receptors VEGF-R1 and VEGF-R2, can induce endothelial cell migration, proliferation and angiogenesis. However, the molecular mechanism of these effects still remains unclear. In this study, we investigated whether VEGF promotes human umbilical vascular endothelial cell (HUVEC) migration and proliferation through activator protein-1 transcription factor (AP-1) family. We first showed that VEGF induces immediate-early genes AP-1 family gene expression differentially with the profound induction of JunB (both mRNA and protein) under various conditions (PBS, DMSO or control adenoviruses). The increase in AP-1 mRNA expression occurs primarily at the transcriptional level. Inhibition of AP-1 DNA binding activity by adenovirus expressing a potent dominant negative form of c-Fos (Afos) significantly attenuated VEGF-induced HUVEC migration and proliferation and cyclin D1 expression. Knockdown of JunB with adenovirus expressing JunB shRNA reduces VEGF-induced JunB expression and attenuated HUVEC migration. However the shJunB-expressing virus has no effect on VEGF-induced cyclin D1 protein expression and proliferation. These results suggest that VEGF-induced endothelial migration is mediated primarily by induction of JunB whereas the promotion of endothelial proliferation by VEGF is mediated by JunB-independent AP-1 family members.

Cardioprotective effect of miRNA-22 on hypoxia/reoxygenation induced cardiomyocyte injury in neonatal rats

MicroRNAs (miRNAs) are implicated in the regulation of pathological and physiological processes in myocardial ischemia/reperfusion (MI/R). Recent studies have revealed that miR-22 might provide a potential cardioprotective effect on ischemic heart disease. However, the mechanism by which miR-22 prevents MI/R is still not fully clear. Here, we investigated the role of miR-22 in hypoxia/reoxygenation (H/R)-induced cardiomyocyte injury. MI/R was simulated in neonatal rat cardiomyocytes with 2h hypoxia followed by 4h reoxygenation. Prior to H/R, cells were transfected by Ad-miR-22 or Ad-scramble. It was revealed that H/R dramatically increased the release of CK and LDH, accompanied by a downregulation of miR-22 expression. Overexpression of miR-22 attenuated cardiomyocyte apoptosis and miR-22 target gene CREB binding protein (CBP) protein level, as determined by flow cytometry analysis and Western blot respectively. We further identified that miR-22 significantly inhibited CBP-related transcriptional factor AP-1 DNA binding activity under H/R. In addition, miR-22 could efficiently change Bcl-2/Bax ratio, and suppress the production of pro-inflammatory cytokines (TNF-α and IL-6) induced by H/R. In conclusion, these results suggest that miR-22 plays an important cardioprotective role partly via regulating CBP/AP-1 pathway to reduce cell apoptosis and inflammatory damage during MI/R injury.

Genome-wide investigation and expression analysis of AP2-ERF gene family in salt tolerant common bean.

Apetala2-ethylene-responsive element binding factor (AP2-ERF) superfamily with common AP2-DNA binding domain have developmentally and physiologically important roles in plants. Since common bean genome project has been completed recently, it is possible to identify all of the AP2-ERF genes in the common bean genome. In this study, a comprehensive genome-wide in silico analysis identified 180 AP2-ERF superfamily genes in common bean (Phaseolus vulgaris). Based on the amino acid alignment and phylogenetic analyses, superfamily members were classified into four subfamilies: DREB (54), ERF (95), AP2 (27) and RAV (3), as well as one soloist. The physical and chemical characteristics of amino acids, interaction between AP2-ERF proteins, cis elements of promoter region of AP2-ERF genes and phylogenetic trees were predicted and analyzed. Additionally, expression levels of AP2-ERF genes were evaluated by in silico and qRT-PCR analyses. In silico micro-RNA target transcript analyses identified nearly all PvAP2-ERF genes as targets of by 44 different plant species' miRNAs were identified in this study. The most abundant target genes were PvAP2/ERF-20-25-62-78-113-173. miR156, miR172 and miR838 were the most important miRNAs found in targeting and BLAST analyses. Interactome analysis revealed that the transcription factor PvAP2-ERF78, an ortholog of Arabidopsis At2G28550, was potentially interacted with at least 15 proteins, indicating that it was very important in transcriptional regulation. Here we present the first study to identify and characterize the AP2-ERF transcription factors in common bean using whole-genome analysis, and the findings may serve as a references for future functional research on the transcription factors in common bean.