关键词： Activating transcription factor 3   anti-inflammatory agents   cytokines   diabetes mellitus   fibroblasts   periodontitis   NF-KAPPA-B   PERIODONTAL-DISEASE   IN-VITRO   GROWTH-FACTOR   FACTOR-ALPHA   CELLS   IL-6   TISSUE   ATF3   MACROPHAGES  

摘要： Background: Chronic periodontitis, one of the most prevalent oral diseases, is associated with Porphyromonas gingivalis (Pg) lipopolysaccharide (LPS) infection and has profound effects on type 2 diabetes mellitus (t2DM). Metformin, a well-known antidiabetic agent, has been reported to exert antiinflammatory effects on various cells. This study aims to investigate the role of metformin on LPS-influenced inflammatory response in human gingival fibroblasts (HGFs). Methods: Dose-dependent additive effects of metformin on LPS-influenced HGFs were detected. Cell-counting assay was used to determine effects of metformin and LPS on viability of HGFs. Enzyme-linked immunosorbent assay and quantitative real-time polymerase chain reaction (qRT-PCR) were applied to detect levels of interleukin (IL)-1 beta, IL-6, and tumor necrosis factor (TNF)-alpha in differently treated cells. Activating transcription factor-3 (ATF3) small interfering (si) RNA transfection was used to determine the mechanism of metformin action, and the transfection efficiency was observed by fluorescence microscope. Effects of ATF3 knockdown were determined by qRT-PCR and Western blot. Results: Results showed that 5 mu g/mL Pg LPS and 0.1, 0.5, and 1 mM metformin exhibited no toxicity to HGFs, and metformin inhibited LPS-influenced IL-1b, IL-beta, and TNF-alpha production in a dose-dependent manner. Metformin and LPS could synergistically facilitate ATF3 expression, and ATF3 knockdown abolished inhibitory effects of metformin on LPS-influenced inflammatory cytokine production in HGFs. Conclusion: The present study confirms that metformin suppresses LPS-enhanced IL-6, IL-1 beta, and TNF-alpha production in HGFs via increasing ATF3 expression.

关键词： ACTIVATING TRANSCRIPTION FACTOR-3   UNFOLDED PROTEIN RESPONSE   CELLULAR SENESCENCE   HUMAN FIBROBLASTS   SECRETORY PHENOTYPE   GENE-EXPRESSION   PATHWAY   KINASE   ATF3   NMD  

摘要： Persistent DNA damage induces profound alterations in gene expression that, in turn, influence tissue homeostasis, tumorigenesis, and cancer treatment outcome. However, the underlying mechanism for gene expression reprogramming induced by persistent DNA damage remains poorly understood. Here, using a highly effective bioluminescence-based reporter system and other tools, we report that persistent DNA damage inhibits nonsense-mediated RNA decay (NMD), an RNA surveillance and gene-regulatory pathway, in noncycling cells. NMD suppression by persistent DNA damage required the activity of the p38 alpha MAPK. Activating transcription factor 3 (ATF3), anNMD target and a key stress-inducible transcription factor, was stabilized in a p38 alpha-and NMD-dependent manner following persistent DNA damage. Our results reveal a novel p38 alpha-dependent pathway that regulates NMD activity in response to persistent DNA damage, which, in turn, controls ATF3 expression in affected cells.

关键词： PNS   Axon regeneration   Facial nerve   ATF3   Muscle   SKELETAL-MUSCLE   AXONAL REGENERATION   ANIMAL-MODELS   RECOVERY   REPAIR   TRANSECTION   RELEVANCE   RAT  

摘要： Traumatic injuries to human peripheral nerves are frequently associated with damage to nerve surrounding tissues including muscles and blood vessels. Currently, most rodent models of peripheral nerve injuries (e.g., facial or sciatic nerve) employ surgical nerve transection with scissors or scalpels. However, such an isolated surgical nerve injury only mildly damages neighboring tissues and weakly activates an immune response. In order to provide a rodent nerve injury model accounting for such nerve-associated tissue damage and immune cell activation, we developed a drop tower-based facial nerve trauma model in mice. We compare nerve regeneration in this novel peripheral nerve trauma model with the established surgical nerve injury along several parameters. These include gene expression, histological and functional facial motoneuron (FMN) regeneration, facial nerve degeneration, immune cell activation and muscle damage. Regeneration-associated genes (RAGs; e.g., Atf3) were strongly induced in FMNs subjected to traumatic and surgical injury. Regeneration of FMNs and functional recovery of whisker movement were faster in traumatic versus complete surgical injury, thus cutting down experimentation time. Wallerian degeneration of distal nerve stumps was readily observed in this novel trauma injury model. Importantly, drop tower-inflicted facial nerve injury resulted in muscle damage, activation of muscle satellite cell markers (PAX7) and pronounced infiltration of immune cells to the injury site only in this model but not upon surgical nerve transection. Thus, we provide a novel rodent PNS trauma model that can be easily adopted to other PNS nerves such as the sciatic nerve. Since this nerve trauma model replicates multiple tissue damage frequently encountered in clinical routine, it will be well suited to identify molecular and cellular mechanisms of PNS nerve repair in wild-type and genetically modified rodents.

关键词： activating transcription factor-3 (ATF3)   inflammation   Mycoplasma pneumonia (MP)   ACTIVATING TRANSCRIPTION FACTOR-3   NLRP3 INFLAMMASOME   NEGATIVE REGULATOR   EPIDEMIOLOGY   DEFICIENCY   PROTECTS   CELLS   GENE   INFECTIONS   INDUCTION  

摘要： ObjectivesActivating transcription factor-3 (ATF3) is a key regulator of inflammatory responses. We aimed to investigate the effects and mechanisms of ATF3 on the inflammatory cytokines are induced by Mycoplasma pneumonia (MP). Study DesignRAW264.7 and mouse peritoneal macrophages were exposed to various time with or without MP infection (3, 6, 12, 24, and 48h), and detect the expression of ATF3. Adenovirus-expression of ATF3 (Ad/ATF3) or Ad/gal was transfected into cells which were exposed to MP for 48h, RT-PCR and ELISA was used to evaluate the expression and secretion of TNF-, IL-1, IL-6, and IL-18. In addition, intravenous administration Ad/ATF3 or Ad/gal into the mice, the secretion of inflammatory cytokines were detected using ELISA. ChIP assay was used to determine whether ATF3 can bind to the promoter of Early growth response protein 1 (Egr-1). Western blot was used to detect the expression of Egr-1 and Fyn. ResultsATF3 was increased at 3, 6, 12, and 24h and the highest expression levels occurs in 6h, there is no significant differences at 24 and 48h compared with 0h or CON group in RAW 264.7. Similar results were seen in mouse peritoneal macrophages. Overexpression of ATF3 resulted in the reduction of inflammatory cytokines. ChIP assay revealed that ATF3 can bind to the promoter of Egr-1. Overexpression of ATF3 inhibited the protein expression of Egr-1 and Fyn; conversely, ATF3-deficiency promoted the expression of Egr-1 and Fyn. Overexpression of Egr-1 reduced the anti-inflammatory action of ATF3. ConclusionsATF3 inhibit the expression and release of TNF-, IL-1, IL-6, and IL-18 induced by MP in vitro and in vivo, which is associated with its negative regulation of Egr-1/Fyn signaling pathway.

关键词： Peripheral nerve injury   Minocycline   CNTF   Colchicine   CILIARY NEUROTROPHIC FACTOR   MOTOR-NEURONS   INJURY   ACTIVATION   BRAIN   CELLS   REMYELINATION   POLARIZATION   REGENERATION   MOTONEURONS  

摘要： Microglia are essential in developmental processes and maintenance of neuronal homeostasis. Experimental axotomy of motor neurons results in neurodegeneration, and microglia in motor nuclei become activated and migrate towards injured neurons. However, whether these activated microglia are protective or destructive to neurons remains controversial. In the present study, we transected the hypo-glossal nerve in BALB/c mice, causing activating transcription factor 3 (ATF3) and growth associated protein 43 (GAP43) induction, and partial neuronal death. Inhibition of microglial accumulation by minocycline administration impaired microglial accumulation, decreased GAP43 mRNA expression, and reduced motor neuron survival. Expression of ATF3 contributed to nerve regeneration, and increased within 6 h after axotomy, prior to microglial migration. Further, microglial contact with neuronal cell bodies was associated with neuronal ATF3 expression. Colchicine administration blocked lesion-induced ATF3 transcription in axotomized neurons and microglial accumulation. In addition, perineuronal microglia-derived ciliary neurotrophic factor (CNTF) increased, indicating that perineuronal microglia in the hypoglossal nucleus protect axotomized motor neurons by releasing trophic factors. We also observed that microglia secrete CNTF and that neurons have CNTFR alpha and can respond to it in vitro. CNTF promote neurite elongation and neuronal survival of primary cultured neurons. Microglia make contact through unknown neuronal signals that are possibly regulated by ATF3 in hypoglossal nucleus. Moreover, they play important roles in regenerating motor neurons and are potential new therapeutic targets for motor neuron diseases. (C) 2017 Elsevier Ltd. All rights reserved.

关键词： Ebselen   IL-6   IL-1   Cancer induced inflammation   ACTIVATING TRANSCRIPTION FACTOR-3   KAPPA-B   INFLAMMASOME   CANCER   REQUIREMENT   MACROPHAGES   METASTASIS   IL-1-BETA   REGULATOR   PSORIASIS  

摘要： Background: Chronic inflammatory skin diseases are characterized by controlled proliferation of keratinocytes. Here, activating transcription factor 3 (ATF3) might play a fundamental role. In these inflammatory diseases, proliferation is controlled and only rarely leads to cancer development which can be supported by an inflammatory microenvironment. ATF3 is a dual function protein as it suppresses pro inflammatory IL-6 and IL-8, but also acts as a pro-oncogenic factor by the suppression of p53. We therefore analyzed ATF3 expression comparing myeloid cells with keratinocytes. Objective: To dissect the bi-modal role of ATF3 we pharmacologically induced ATF3 and analyzed its influence on cytokine expression and secretion in a cell type specific manner. Methods: Since inflammatory skin diseases can be treated systemically with Cyclosporin A or Dimethylfumarate we stimulated myeloid cells and primary human keratinocytes with these drugs and analyzed gene expression by quantitative real-time PCR. Cytokine secretion was measured by ELISA. Results: In the present study, we could show that ATF3 is induced in PBMCs by DMF and weakly by Ebselen, while CsA is the most prominent inducer of ATF3 in keratinocytes without enhancing HO-1 transcription. Further we could show that induction of stress by LPS treatment elevates IL-1 beta and IL-6 and weakly ATF3 transcription in PBMCs. While transcription of both cytokines is elevated, LPS treatment mediates IL-6 secretion with only little IL-1 beta secretion. Treatment with DMF dampens LPS-induced transcription. Conclusions: Taken together, our results shed light into the different carcinogenic potential of CsA and DMF, which both target ATF3. Collectively our data demonstrate that CsA strongly induces pro carcinogenic ATF3 in keratinocytes, whereas ATF3 induction by DMF in myeloid cells acts antiinflammatory. (C) 2017 Japanese Society for Investigative Dermatology. Published by Elsevier Ireland Ltd. All rights reserved.

关键词： activating transcription factor 3   macrophage   M1/M2 polarization   tenascin-C   RENAL ISCHEMIA-REPERFUSION   ALTERNATIVE ACTIVATION   NERVE INJURY   LUNG INJURY   GENE   TRANSCRIPTION   INFLAMMATION   EXPRESSION   PROTECTS   REGULATOR  

摘要： There are different polarization states of macrophages, including the classically activated M1 phenotype and the alternatively activated M2 phenotype. These have different functions in the inflammation process. Activating transcription factor 3 (ATF3) is a key transcriptional regulator that inhibits the inflammatory response. However, the effects of ATF3 on migration and anti-inflammatory control mechanisms of macrophages have not been thoroughly investigated. The present study investigated the effect of ATF3 on macrophage migration and M1/M2 polarization. Results revealed that overexpression of ATF3 promoted macrophage migration and the expression of the M2 phenotype markers [cluster of differentiation (CD) 163, mannose receptor C type 1, arginase 1 and peroxisome proliferator-activated receptor gamma] and inhibited expression of the M1 phenotype markers (monocyte chemoattractant protein-1, inducible nitric oxide synthase, CD16 and tumor necrosis factor-alpha), whereas knockdown of ATF3 resulted in a contrary effect. In addition, the wingless-type MMTV integration site family member (Wnt)/beta-catenin signaling pathway was activated and the expression level of tenascin (TNC) was significantly upregulated by overexpression of ATF3. Additionally, inhibition of Wnt/beta-catenin signaling significantly attenuated the upregulatory effect of ATF3 on TNC. Finally, the effect of ATF3 on macrophage migration and markers of the M1 or M2 state was investigated using TNC-specific siRNA. In conclusion, the results of the present study suggested that ATF3 promotes macrophage migration and reverses M1-polarized macrophages to the M2 phenotype by upregulation of TNC via the Wnt/beta-catenin signaling pathway.

关键词： chemotherapy   metastasis   stress response   immune modulation   ATF3   ACTIVATING TRANSCRIPTION FACTOR-3   TUMOR-INFILTRATING MACROPHAGES   ADAPTIVE-RESPONSE   PACLITAXEL   INFLAMMATION   RESISTANCE   EXPRESSION   MONOCYTES   CARCINOMA   THERAPY  

摘要： Chemotherapy is a double-edged sword. It is anticancer because of its cytotoxicity. Paradoxically, by increasing chemoresistance and cancer metastasis, it is also procancer. However, the underlying mechanisms for chemotherapy-induced procancer activities are not well understood. Here we describe the ability of paclitaxel (PTX), a frontline chemotherapeutic agent, to exacerbate metastasis in mouse models of breast cancer. We demonstrate that, despite the apparent benefit of reducing tumor size, PTX increased the circulating tumor cells in the blood and enhanced the metastatic burden at the lung. At the primary tumor, PTX increased the abundance of the tumor microenvironment of metastasis, a landmark microanatomical structure at the microvasculature where cancer cells enter the blood stream. At the metastatic lung, PTX improved the tissue microenvironment (the "soil") for cancer cells (the "seeds") to thrive; these changes include increased inflammatory monocytes and reduced cytotoxicity. Importantly, these changes in the primary tumor and the metastatic lung were all dependent on Atf3, a stress-inducible gene, in the noncancer host cells. Together, our data provide mechanistic insights into the procancer effect of chemotherapy, explaining its paradox in the context of the seed-and-soil theory. Analyses of public datasets suggest that our data may have relevance to human cancers. Thus, ATF3 in the host cells links a chemotherapeutic agent-a stressor-to immune modulation and cancer metastasis. Dampening the effect of ATF3 may improve the efficacy of chemotherapy.

关键词： ACTIVATING TRANSCRIPTION FACTOR-3   UP-REGULATION   OXIDATIVE STRESS   ATF3   RESISTANCE   PROTEIN   STREPTOMYCIN   SENSITIVITY   PROGRESSION   MECHANISM  

摘要： Standard cell culture guidelines often use media supplemented with antibiotics to prevent cell contamination. However, relatively little is known about the effect of antibiotic use in cell culture on gene expression and the extent to which this treatment could confound results. To comprehensively characterize the effect of antibiotic treatment on gene expression, we performed RNA-seq and ChIP-seq for H3K27ac on HepG2 cells, a human liver cell line commonly used for pharmacokinetic,metabolism and genomic studies, cultured in media supplemented with penicillin-streptomycin (PenStrep) or vehicle control. We identified 209 PenStrep-responsive genes, including transcription factors such as ATF3 that are likely to alter the regulation of other genes. Pathway analyses found a significant enrichment for "xenobiotic metabolism signaling" and "PXR/RXR activation" pathways. Our H3K27ac ChIP-seq identified 9,514 peaks that are PenStrep responsive. These peaks were enriched near genes that function in cell differentiation, tRNA modification, nuclease activity and protein dephosphorylation. Our results suggest that PenStrep treatment can significantly alter gene expression and regulation in a common liver cell type such as HepG2, advocating that antibiotic treatment should be taken into account when carrying out genetic, genomic or other biological assays in cultured cells.

关键词： Non-alcoholic fatty liver disease   Oxidative stress   Zucker diabetic fatty rat   Human patients   In vivo silencing   Activation transcription factor 3   BETA-CELL DYSFUNCTION   INSULIN-RESISTANCE   ATF3   STRESS   PROGRESSION   METABOLISM   REGULATOR   PROTEIN   DIET   LIFE  

摘要： Background & Aims: Non-alcoholic fatty liver disease (NAFLD) contributes to impaired glucose tolerance, leading to type 2 diabetes (T2D); however, the precise mechanisms and target molecules that are involved remain unclear. Activating transcription factor 3 (ATF3) is associated with beta-cell dysfunction that is induced by severe stress signals in T2D. We aimed to explore the exact functional role of ATF3 as a mechanistic link between hepatic steatosis and T2D development. Methods: Zucker diabetic fatty (ZDF) rats were utilized for animal experiments. An in vivo-jetPEI siRNA delivery system against ATF3 was used for loss-of-function experiments. We analyzed the baseline cross-sectional data derived from the biopsy-proven NAFLD registry (n = 322). Human sera and liver tissues were obtained from 43 patients with biopsy-proven NAFLD and from seven healthy participants. Results: ATF3 was highly expressed in the livers of ZDF rats and in human participants with NAFLD and/or T2D. Insulin resistance and hepatic steatosis were associated with increased ATF3 expression and decreased fatty acid oxidation via mitochondrial dysfunction and were attenuated by in vivo ATF3 silencing. Knockdown of ATF3 also ameliorated glucose intolerance, impaired insulin action, and inflammatory responses in ZDF rats. In patients with NAFLD and/or T2D, a significant positive correlation was observed between hepatic ATF3 expression and surrogate markers of T2D, mitochondrial dysfunction, and macrophage infiltration. Conclusions: Increased hepatic ATF3 expression is closely associated with hepatic steatosis and incident T2D; therefore, ATF3 may serve as a potential therapeutic target for NAFLD and hepatic steatosis-induced T2D. Lay summary: Hepatic activating transcription factor 3 (ATF3) may play an important role in oxidative stress-mediated hepatic steatosis and the development of type 2 diabetes (T2D) in a Zucker diabetic fatty (ZDF) rat model and in human patients with non-alcoholic fatty li