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BACKGROUND: Region-specific immune environments in the epididymis influence the immune responses to uropathogenic Escherichia coli (UPEC) infection, a relevant cause of epididymitis in men. Toll-like receptors (TLRs) are essential to orchestrate immune responses against bacterial infections. The epididymis displays region-specific inflammatory responses to bacterial-derived TLR agonists, such as lipopolysaccharide (LPS; TLR4 agonist) and lipoteichoic acid (LTA; TLR2/TLR6 agonist), suggesting that TLR-associated signaling pathways could influence the magnitude of inflammatory responses in epididymitis. OBJECTIVES: To investigate the expression and regulation of key genes associated with TLR4 and TLR2/TLR6 signaling pathways during epididymitis induced by UPEC, LPS, and LTA in mice. MATERIAL AND METHODS: Epididymitis was induced in mice using UPEC, ultrapure LPS, or LTA, injected into the interstitial space of the initial segment or the lumen of the vas deferens close to the cauda epididymidis. Samples were harvested after 1, 5, and 10 days for UPEC-treated animals and 6 and 24 h for LPS-/LTA-treated animals. Ex vivo epididymitis was induced by incubating epididymal regions from naive mice with LPS or LTA. RT-qPCR and Western blot assays were conducted. RESULTS: UPEC infection up-regulated Tlr2, Tlr4, and Tlr6 transcripts and their associated signaling molecules Cd14, Ticam1, and Traf6 in the cauda epididymidis but not in the initial segment. In these epididymal regions, LPS and LTA differentially modulated Tlr2, Tlr4, Tlr6, Cd14, Myd88, Ticam1, Traf3, and Traf6 expression levels. NFKB and AP1 activation was required for LPS- and LTA-induced up-regulation of TLR-associated signaling transcripts in the cauda epididymidis and initial segment, respectively. CONCLUSION: The dynamic modulation of TLR4 and TLR2/TLR6 signaling pathways gene expression during epididymitis indicates bacterial-derived antigens elicit an increased tissue sensitivity to combat microbial infection in a spatial manner in the epididymis. Differential activation of TLR-associated signaling pathways may contribute to fine-tuning inflammatory responses along the epididymis.
Assuntos
Epididimite , Lipopolissacarídeos , Transdução de Sinais , Ácidos Teicoicos , Receptor 2 Toll-Like , Receptor 4 Toll-Like , Animais , Masculino , Epididimite/genética , Epididimite/metabolismo , Epididimite/microbiologia , Camundongos , Receptor 4 Toll-Like/metabolismo , Receptor 4 Toll-Like/genética , Receptor 2 Toll-Like/genética , Receptor 2 Toll-Like/metabolismo , Ácidos Teicoicos/farmacologia , Escherichia coli Uropatogênica , Infecções por Escherichia coli/imunologia , Infecções por Escherichia coli/genética , Receptor 6 Toll-Like/genética , Receptor 6 Toll-Like/metabolismo , Epididimo/metabolismo , Fator 6 Associado a Receptor de TNF/metabolismo , Fator 6 Associado a Receptor de TNF/genética , Fator 88 de Diferenciação Mieloide/genética , Fator 88 de Diferenciação Mieloide/metabolismo , Camundongos Endogâmicos C57BL , Doença AgudaRESUMO
Selective retrograde transport from endosomes back to the trans-Golgi network (TGN) is important for maintaining protein homeostasis, recycling receptors, and returning molecules that were transported to the wrong compartments. Two important transmembrane proteins directed to this pathway are the Cation-Independent Mannose-6-phosphate receptor (CI-MPR) and the ATP7B copper transporter. Among CI-MPR functions is the delivery of acid hydrolases to lysosomes, while ATP7B facilitates the transport of cytosolic copper ions into organelles or the extracellular space. Precise subcellular localization of CI-MPR and ATP7B is essential for the proper functioning of these proteins. This study shows that both CI-MPR and ATP7B interact with a variant of the clathrin adaptor 1 (AP-1) complex that contains a specific isoform of the γ-adaptin subunit called γ2. Through synchronized anterograde trafficking and cell-surface uptake assays, we demonstrated that AP-1γ2 is dispensable for ATP7B and CI-MPR exit from the TGN while being critically required for ATP7B and CI-MPR retrieval from endosomes to the TGN. Moreover, AP-1γ2 depletion leads to the retention of endocytosed CI-MPR in endosomes enriched in retromer complex subunits. These data underscore the importance of AP-1γ2 as a key component in the sorting and trafficking machinery of CI-MPR and ATP7B, highlighting its essential role in the transport of proteins from endosomes.
Assuntos
Complexo 1 de Proteínas Adaptadoras , ATPases Transportadoras de Cobre , Endossomos , Transporte Proteico , Receptor IGF Tipo 2 , Rede trans-Golgi , Humanos , Endossomos/metabolismo , Células HeLa , Transporte Proteico/genética , Receptor IGF Tipo 2/genética , Receptor IGF Tipo 2/metabolismo , Rede trans-Golgi/genética , Rede trans-Golgi/metabolismo , ATPases Transportadoras de Cobre/genética , ATPases Transportadoras de Cobre/metabolismo , Complexo 1 de Proteínas Adaptadoras/genética , Complexo 1 de Proteínas Adaptadoras/metabolismo , Subunidades gama do Complexo de Proteínas Adaptadoras/metabolismoRESUMO
BACKGROUND: Growing evidence has suggested that Type I Interferon (I-IFN) plays a potential role in the pathogenesis of Down Syndrome (DS). This work investigates the underlying function of MX1, an effector gene of I-IFN, in DS-associated transcriptional regulation and phenotypic modulation. METHODS: We performed assay for transposase-accessible chromatin with high-throughout sequencing (ATAC-seq) to explore the difference of chromatin accessibility between DS derived amniocytes (DSACs) and controls. We then combined the annotated differentially expressed genes (DEGs) and enriched transcriptional factors (TFs) targeting the promoter region from ATAC-seq results with the DEGs in RNA-seq, to identify key genes and pathways involved in alterations of biological processes and pathways in DS. RESULTS: Binding motif analysis showed a significant increase in chromatin accessibility of genes related to neural cell function, among others, in DSACs, which is primarily regulated by members of the activator protein-1 (AP-1) transcriptional factor family. Further studies indicated that MX Dynamin Like GTPase 1 (MX1), defined as one of the key effector genes of I-IFN, is a critical upstream regulator. Its overexpression induced expression of AP-1 TFs and mediated inflammatory response, thus leading to decreased cellular viability of DS cells. Moreover, treatment with specific AP-1 inhibitor T-5224 improved DS-associated phenotypes in DSACs. CONCLUSIONS: This study demonstrates that MX1-mediated AP-1 activation is partially responsible for cellular dysfunction of DS. T-5224 effectively ameliorated DS-associated phenotypes in DSACs, suggesting it as a potential treatment option for DS patients.
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Síndrome de Down , Fator de Transcrição AP-1 , Humanos , Fator de Transcrição AP-1/genética , Fator de Transcrição AP-1/metabolismo , Sequenciamento de Cromatina por Imunoprecipitação , RNA-Seq , Síndrome de Down/tratamento farmacológico , Síndrome de Down/genética , Cromatina , Proteínas de Resistência a Myxovirus/genética , Proteínas de Resistência a Myxovirus/metabolismoRESUMO
This study describes, to some extent, the VCC contribution as an early stimulation of the macrophage lineage. Regarding the onset of the innate immune response caused by infection, the ß form of IL-1 is the most important interleukin involved in the onset of the inflammatory innate response. Activated macrophages treated in vitro with VCC induced the activation of the MAPK signaling pathway in a one-hour period, with the activation of transcriptional regulators for a surviving and pro-inflammatory response, suggesting an explanation inspired and supported by the inflammasome physiology. The mechanism of IL-1ß production induced by VCC has been gracefully outlined in murine models, using bacterial knockdown mutants and purified molecules; nevertheless, the knowledge of this mechanism in the human immune system is still under study. This work shows the soluble form of 65 kDa of the Vibrio cholerae cytotoxin (also known as hemolysin), as it is secreted by the bacteria, inducing the production of IL-1ß in the human macrophage cell line THP-1. The mechanism involves triggering the early activation of the signaling pathway MAPKs pERK and p38, with the subsequent activation of (p50) NF-κB and AP-1 (cJun and cFos), determined by real-time quantitation. The evidence shown here supports that the monomeric soluble form of the VCC in the macrophage acts as a modulator of the innate immune response, which is consistent with the assembly of the NLRP3 inflammasome actively releasing IL-1ß.
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NF-kappa B , Vibrio cholerae , Humanos , Animais , Camundongos , NF-kappa B/metabolismo , Fator de Transcrição AP-1/metabolismo , Inflamassomos/metabolismo , Vibrio cholerae/metabolismo , Ativação Transcricional , Citotoxinas/farmacologia , Transdução de Sinais , Macrófagos/metabolismo , Células THP-1 , Interleucina-1beta/metabolismo , Proteína 3 que Contém Domínio de Pirina da Família NLR/metabolismoRESUMO
Zika virus (ZIKV) is an arbovirus of the Flaviviridae genus that has rapidly disseminated from across the Pacific to the Americas. Robust evidence has indicated a crucial role of ZIKV in congenital virus syndrome, including neonatal microcephaly. Moreover, emerging evidence suggests an association between ZIKV infection and the development of an extensive spectrum of central nervous system inflammatory demyelinating diseases (CNS IDD), such as multiple sclerosis-like clinical phenotypes. However, the underlying mechanisms of host-pathogen neuro-immune interactions remain to be elucidated. This study aimed to identify common transcriptional signatures between multiple sclerosis (MS) and ZIKV infection to generate molecular interaction networks, thereby leading to the identification of deregulated processes and pathways, which could give an insight of these underlying molecular mechanisms. Our investigation included publicly available transcriptomic data from MS patients in either relapse or remission (RR-MS) and datasets of subjects acutely infected by ZIKV for both immune peripheral cells and central nervous system cells. The protein-protein interaction (PPI) analysis showed upregulated AP-1 transcription factors (JUN and FOS) among the top hub and bottleneck genes in RR-MS and ZIKV data. Gene enrichment analysis retrieved a remarkable presence of ontologies and pathways linked to oxidative stress responses, immune cell function, inflammation, interleukin signaling, cell division, and transcriptional regulation commonly enriched in both scenarios. Considering the recent findings concerning AP-1 function in immunological tolerance breakdown, regulation of inflammation, and its function as an oxidative stress sensor, we postulate that the ZIKV trigger may contribute as a boost for the activation of such AP-1-regulated mechanisms that could favor the development of MS-like phenotypes following ZIKV infection in a genetically susceptible individual.
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Esclerose Múltipla , Infecção por Zika virus , Zika virus , Humanos , Infecção por Zika virus/complicações , Infecção por Zika virus/genética , Zika virus/genética , Fator de Transcrição AP-1/genética , Esclerose Múltipla/genética , Inflamação , FenótipoRESUMO
When tumoral cell expansion exceeds the vascular supply, regions of hypoxia or low oxygen concentration are generated promoting the formation of new vessels through cell proliferation and migration. Viral G protein-coupled receptor (vGPCR) is associated to Kaposi's sarcoma pathology and induces a paracrine transformation when is stably expressed in murine endothelial cells activating hypoxia-induced transcription factors. Previously, we reported the antiproliferative actions of 1α,25-dihydroxyvitamin D3 (1α,25(OH)2D3) in endothelial cells transformed by the vGPCR (SVEC-vGPCR). Herein, we further investigated if pro-angiogenic factors as AP-1, HIF-1α and VEGF are modulated by 1α,25(OH)2D3. We found by qRT-PCR analysis that the mRNA level of JunB, a negative regulator of cell proliferation, was similarly increased at all-time points tested after 1α,25(OH)2D3 treatment in SVEC-vGPCR cells. Also, mRNA levels of the pro-angiogenic factor c-Fos, which induces tumor invasion, were only decreased during one short period treatment. In addition, Hif-1α mRNA and protein levels were significantly reduced after 1α,25(OH)2D3 treatment in a VDR dependent fashion. However, mRNA levels of the angiogenic activator Vegf, promoted in turn by Hif-1α expression, were surprisingly high depending on VDR expression as well. Moreover, Egr-1, which has been reported to induce VEGF expression independently of HIF-1α, diminished its expression with 1α,25(OH)2D3 treatment, fact that was related to the decline of p-ERK1/2. Altogether, these results suggest a negative modulation of some pro-angiogenic factors like AP-1 and HIF-1α, as part of the antiproliferative mechanism of 1α,25(OH)2D3 in SVEC-vGPCR endothelial cells.
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Células Endoteliais , Herpesvirus Humano 8 , Camundongos , Animais , Células Endoteliais/metabolismo , Herpesvirus Humano 8/genética , Herpesvirus Humano 8/metabolismo , Indutores da Angiogênese/metabolismo , Fator A de Crescimento do Endotélio Vascular/genética , Fator de Transcrição AP-1/metabolismo , Receptores Acoplados a Proteínas G/genética , Receptores Acoplados a Proteínas G/metabolismo , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Hipóxia/metabolismoRESUMO
Trichophyton rubrum is a fungus that causes chronic skin and nail infections in healthy individuals and immunocompromised patients. During infection, T. rubrum invades host cutaneous tissues by adapting to the acidic pH and the innate immune response of the host. Several genes are upregulated during the growth of T. rubrum in substrates found in human tissue, including the ap1 gene, which codes for the transcription factor Ap1. Here, we generated a null mutant strain by deleting the T. rubrum ap1 gene and performed a functional analysis of this gene. Our results showed that the Δap1mutant increased its growth in nail fragments and co-cultures with keratinocytes compared to the wild type. Furthermore, the mutant displayed hyperpigmentation, thickening of the conidia cell wall, increased conidia susceptibility to calcofluor-white compared to the wild type, and loss of control of the keratinolytic activity. Although the ap1 gene was upregulated during exposure to the antifungal drugs amphotericin B, nystatin, and terbinafine, its deletion did not alter the fungal susceptibility to these drugs, revealing the role of the ap1 gene in the physiological response to the stress caused by these drugs, but not in their resistance. Moreover, ap1 was also involved in the oxidative stress response caused by menadione, but not paraquat or hydrogen peroxide. These findings indicate that the ap1 gene plays a role in the negative control of virulence-related attributes and may contribute to the chronicity of nail infection caused by T. rubrum.
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Persistent infections with some types of human papillomavirus (HPV) constitute the major etiological factor for cervical cancer development. Nanog, a stem cell transcription factor has been shown to increase during cancer progression. We wanted to determine whether Nanog could modulate transcription of E6 and E7 oncogenes. We used luciferase reporters under the regulation of the long control region (LCR) of HPV types 16 and 18 (HPV16/18) and performed RT-qPCR. We found that Nanog increases activity of both viral regulatory regions and elevates endogenous E6/E7 mRNA levels in cervical cancer-derived cells. We demonstrated by in vitro mutagenesis that changes at Nanog-binding sites found in the HPV18 LCR significantly inhibit transcriptional activation. Chromatin immunoprecipitation (ChIP) assays showed that Nanog binds in vivo to the HPV18 LCR, and its overexpression increases its binding as well as that of c-Jun. Surprisingly, we observed that mutation of AP1-binding sites also affect Nanog's ability to activate transcription, suggesting cooperation between the two factors. We searched for putative Nanog-binding sites in the LCR of several HPVs and surprisingly found them only in those types associated with cancer development. Our study shows, for the first time, a role for Nanog in the regulation of E6/E7 transcription of HPV16/18.
Assuntos
Proteínas de Ligação a DNA/genética , Papillomavirus Humano 16/genética , Papillomavirus Humano 18/genética , Proteína Homeobox Nanog/metabolismo , Proteínas Oncogênicas Virais/genética , Proteínas E7 de Papillomavirus/genética , Infecções por Papillomavirus/metabolismo , Proteínas Repressoras/genética , Linhagem Celular Tumoral , Proteínas de Ligação a DNA/metabolismo , Feminino , Regulação Viral da Expressão Gênica , Interações Hospedeiro-Patógeno , Papillomavirus Humano 16/metabolismo , Papillomavirus Humano 18/metabolismo , Humanos , Proteína Homeobox Nanog/genética , Proteínas Oncogênicas Virais/metabolismo , Proteínas E7 de Papillomavirus/metabolismo , Infecções por Papillomavirus/genética , Infecções por Papillomavirus/virologia , Regiões Promotoras Genéticas , Proteínas Repressoras/metabolismo , Fator de Transcrição AP-1/genética , Fator de Transcrição AP-1/metabolismo , Ativação Transcricional , Neoplasias do Colo do Útero/genética , Neoplasias do Colo do Útero/metabolismo , Neoplasias do Colo do Útero/virologiaRESUMO
Pharmacodynamic interactions between plant isolated compounds are important to understand the mode of action of an herbal extract to formulate or create better standardized extracts, phytomedicines, or phytopharmaceuticals. In this work, we propose binary mixtures using a leader compound to found pharmacodynamic interactions in inhibition of the NF-κB/AP-1 pathway using RAW-Blue™ cells. Eight compounds were isolated from Castilleja tenuiflora, four were new furofuran-type lignans for the species magnolin, eudesmin, sesamin, and kobusin. Magnolin (60.97%) was the most effective lignan inhibiting the NF-κB/AP-1 pathway, followed by eudesmin (56.82%), tenuifloroside (52.91%), sesamin (52.63%), and kobusin (45.45%). Verbascoside, a major compound contained in wild C. tenuiflora showed an inhibitory effect on NF-κB/AP-1. This polyphenol was chosen as a leader compound for binary mixtures. Verbacoside-aucubin and verbascoside-kobusin produced synergism, while verbascoside-tenuifloroside had subadditivity in all concentrations. Verbascoside-kobusin is a promising mixture to use on NF-κB/AP-1 related diseases and anti-inflammatory C. tenuiflora-based phytomedicines.
Assuntos
Anti-Inflamatórios , Glucosídeos , Iridoides , Lignanas , NF-kappa B/antagonistas & inibidores , Orobanchaceae/química , Fenóis , Fator de Transcrição AP-1/antagonistas & inibidores , Animais , Anti-Inflamatórios/química , Anti-Inflamatórios/farmacologia , Linhagem Celular , Glucosídeos/química , Glucosídeos/farmacologia , Iridoides/química , Iridoides/farmacologia , Lignanas/química , Lignanas/farmacologia , Camundongos , NF-kappa B/metabolismo , Fenóis/química , Fenóis/farmacologia , Fator de Transcrição AP-1/metabolismoRESUMO
Differentiation of neuronal cells is crucial for the development and function of the nervous system. This process involves high rates of membrane expansion, during which the synthesis of membrane lipids must be tightly regulated. In this work, using a variety of molecular and biochemical assays and approaches, including immunofluorescence microscopy and FRET analyses, we demonstrate that the proto-oncogene c-Fos (c-Fos) activates cytoplasmic lipid synthesis in the central nervous system and thereby supports neuronal differentiation. Specifically, in hippocampal primary cultures, blocking c-Fos expression or its activity impairs neuronal differentiation. When examining its subcellular localization, we found that c-Fos co-localizes with endoplasmic reticulum markers and strongly interacts with lipid-synthesizing enzymes, whose activities were markedly increased in vitro in the presence of recombinant c-Fos. Of note, the expression of c-Fos dominant-negative variants capable of blocking its lipid synthesis-activating activity impaired neuronal differentiation. Moreover, using an in utero electroporation model, we observed that neurons with blocked c-Fos expression or lacking its AP-1-independent activity fail to initiate cortical development. These results highlight the importance of c-Fos-mediated activation of lipid synthesis for proper nervous system development.
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Córtex Cerebral/embriologia , Neurogênese , Neurônios/citologia , Proteínas Proto-Oncogênicas c-fos/metabolismo , Animais , Células Cultivadas , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Camundongos Endogâmicos C57BL , Neurônios/metabolismo , Proteínas Proto-Oncogênicas c-fos/genética , Ratos , Ratos WistarRESUMO
It has been established that ZFP36 (also known as Tristetraprolin or TTP) promotes mRNA degradation of proteins involved in inflammation, proliferation and tumor invasiveness. In mammary epithelial cells ZFP36 expression is induced by STAT5 activation during lactogenesis, while in breast cancer ZFP36 expression is associated with lower grade and better prognosis. Here, we show that the AP-1 transcription factor components, i.e. JUN, JUNB, FOS, FOSB, in addition to DUSP1, EGR1, NR4A1, IER2 and BTG2, behave as a conserved co-regulated group of genes whose expression is associated to ZFP36 in cancer cells. In fact, a significant down-modulation of this gene network is observed in breast, liver, lung, kidney, and thyroid carcinomas compared to their normal counterparts. In breast cancer, the normal-like and Luminal A, show the highest expression of the ZFP36 gene network among the other intrinsic subtypes and patients with low expression of these genes display poor prognosis. It is also proposed that AP-1 regulates ZFP36 expression through responsive elements detected in the promoter region of this gene. Culture assays show that AP-1 activity induces ZFP36 expression in mammary cells in response to prolactin (PRL) treatment thorough ERK1/2 activation. These results suggest that JUN, JUNB, FOS and FOSB are not only co-expressed, but would also play a relevant role in regulating ZFP36 expression in mammary epithelial cells.
Assuntos
Biomarcadores Tumorais/metabolismo , Neoplasias da Mama/patologia , Mama/metabolismo , Regulação Neoplásica da Expressão Gênica , Redes Reguladoras de Genes , Fator de Transcrição AP-1/metabolismo , Tristetraprolina/metabolismo , Biomarcadores Tumorais/genética , Neoplasias da Mama/genética , Neoplasias da Mama/metabolismo , Biologia Computacional/métodos , Feminino , Humanos , Prognóstico , Fator de Transcrição AP-1/genética , Tristetraprolina/genéticaRESUMO
The HIV-1 accessory protein Nef downregulates the cell surface expression of major histocompatibility complex class I (MHC-I) molecules to facilitate virus spreading. The Nef-induced downregulation of MHC-I molecules such as HLA-A requires the clathrin adaptor protein 1 (AP-1) complex. The cooperative interaction of Nef, AP-1, and the cytosolic tail (CT) of HLA-A leads to a redirection of HLA-A targeting from the trans-Golgi network (TGN) to lysosomes for degradation. Although the γ-adaptin subunit of AP-1 has two distinct isoforms (γ1 and γ2), which may form two AP-1 complex variants, so far, only the importance of AP-1γ1 in MHC-I downregulation by Nef has been investigated. Here, we report that the AP-1γ2 isoform also participates in this process. We found that AP-1γ2 forms a complex with Nef and HLA-A2_CT and that this interaction depends on the Y320 residue in HLA-A2_CT and Nef expression. Moreover, Nef targets AP-1γ1 and AP-1γ2 to different compartments in T cells, and the depletion of either AP-1 variant impairs the Nef-mediated reduction of total endogenous HLA-A levels and rescues HLA-A levels on the cell surface. Finally, immunofluorescence and immunoelectron microscopy analyses reveal that the depletion of γ2 in T cells compromises both the Nef-mediated retention of HLA-A molecules in the TGN and targeting to multivesicular bodies/late endosomes. Altogether, these results show that in addition to AP-1γ1, Nef also requires the AP-1γ2 variant for efficient MHC-I downregulation.IMPORTANCE HIV-1 Nef mediates evasion of the host immune system by inhibiting MHC-I surface presentation of viral antigens. To achieve this goal, Nef modifies the intracellular trafficking of MHC-I molecules in several ways. Despite being the subject of intense study, the molecular details underlying these modifications are not yet fully understood. Adaptor protein 1 (AP-1) plays an essential role in the Nef-mediated downregulation of MHC-I molecules such as HLA-A in different cell types. However, AP-1 has two functionally distinct variants composed of either γ1 or γ2 subunit isoforms. Because previous studies on the role of AP-1 in MHC-I downregulation by Nef focused on AP-1γ1, an important open question is the participation of AP-1γ2 in this process. Here, we show that AP-1γ2 is also essential for Nef-mediated depletion of surface HLA-A molecules in T cells. Our results indicate that Nef hijacks AP-1γ2 to modify HLA-A intracellular transport, redirecting these proteins to lysosomes for degradation.
Assuntos
Regulação para Baixo , Regulação da Expressão Gênica , Antígeno HLA-A2/metabolismo , Fator de Transcrição AP-1/metabolismo , Produtos do Gene nef do Vírus da Imunodeficiência Humana/metabolismo , Subunidades gama do Complexo de Proteínas Adaptadoras/metabolismo , Membrana Celular/metabolismo , Citosol/metabolismo , Endossomos/metabolismo , Células HEK293 , Células HeLa , Humanos , Lisossomos/metabolismo , Microscopia Imunoeletrônica , Transporte Proteico , Linfócitos T/imunologia , Linfócitos T/virologia , Rede trans-Golgi/metabolismoRESUMO
The Fos oncogene gene family is evolutionarily conserved throughout Eukarya. Fos proteins characteristically have a leucine zipper and a basic region with a helix-turn-helix motif that binds DNA. In vertebrates, there are several Fos homologs. They can homo- or hetero-dimerize via the leucine zipper domain. Fos homologs coupled with other transcription factors, like Jun oncoproteins, constitute the Activator Protein 1 (AP-1) complex. From its original inception as an oncogene, the subsequent finding that they act as transcription factors binding DNA sequences known as TRE, to the realization that they are activated in many different scenarios, and to loss-of-function analysis, the Fos proteins have traversed a multifarious path in development and physiology. They are instrumental in 'immediate early genes' responses, and activated by a seemingly myriad assemblage of different stimuli. Yet, the majority of these studies were basically gain-of-function studies, since it was thought that Fos genes would be cell lethal. Loss-of-function mutations in vertebrates were recovered later, and were not cell lethal. In fact, c-fos null mutations are viable with developmental defects (osteopetrosis and myeloid lineage abnormalities). It was then hypothesized that vertebrate genomes exhibit partial redundancy, explaining the 'mild' phenotypes, and complicating assessment of complete loss-of-function phenotypes. Due to its promiscuous activation, fos genes (especially c-fos) are now commonly used as markers for cellular responses to stimuli. fos homologs high sequence conservation (including Drosophila) is advantageous as it allows critical assessment of fos genes functions in this genetic model. Drosophila melanogaster contains only one fos homolog, the gene kayak. kayak mutations are lethal, and allow study of all the processes where fos is required. The kayak locus encodes several different isoforms, and is a pleiotropic gene variously required for development involving cell shape changes. In general, fos genes seem to primarily activate programs involved in cellular architectural rearrangements and cell shape changes.
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Mutação/genética , Proteínas Proto-Oncogênicas c-fos/genética , Animais , DNA/genética , Proteínas de Ligação a DNA/genética , Humanos , Isoformas de Proteínas/genéticaRESUMO
BACKGROUND: To investigate the effect of CXCL12 gene silencing on proliferation,invasion, angiogenesis and the relationship of MAPK/PI3K/AP-1 signaling pathway in colon cancer cells. METHODS: RT-PCR and Western-blot were used to detect the expression of CXCL12 mRNA and protein in four colon cancer cell lines. Human colon cancer cells were transfected with CXCL12 siRNA carrying by Lipofectamine 2000. The expression of CXCL12 protein was confirmed by immunoblotting. WST-1, invasion and angiogenesis assay were used to examine the effect on proliferation, invasion and angiogenesis in colon cancer cells after CXCL12 siRNA silence, respectively. The phosphorylation of MAPK/PI3K/AP-1 protein levels was detected by Western blotting in CXCL12 siRNA suppression DLD-1 cell. RESULTS: CXCL12 mRNA and proteins were only expressed in DLD-1 colon cancer cell lines. CXCL12 siRNA were transfected into DLD-1 cells, the expression CXCL12 proteins was significantly inhibited (P < 0.01), and the proliferation, invasion and angiogenesis of DLD-1 cells were inhibited significantly (P < 0.01). CXCL12 gene silencing resulted in blockage of MAPK, PI3K and AP-1 phosphorylation by CXCL12-induced in DLD-1 colon cancer cell. CONCLUSION: The silencing CXCL12 gene significantly inhibits the proliferation, invasion and angiogenesis ability of some types colon carcinoma cells through down-regulation of MAPK/PI3K/AP-1 signaling pathway.
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Quimiocina CXCL12/antagonistas & inibidores , Neoplasias do Colo/secundário , Regulação Neoplásica da Expressão Gênica , Proteínas Quinases Ativadas por Mitógeno/metabolismo , Fosfatidilinositol 3-Quinases/metabolismo , RNA Interferente Pequeno/genética , Fator de Transcrição AP-1/metabolismo , Apoptose , Movimento Celular , Proliferação de Células , Quimiocina CXCL12/genética , Quimiocina CXCL12/metabolismo , Neoplasias do Colo/genética , Neoplasias do Colo/metabolismo , Inativação Gênica , Humanos , Proteínas Quinases Ativadas por Mitógeno/genética , Invasividade Neoplásica , Neovascularização Patológica , Fosfatidilinositol 3-Quinases/genética , Fosforilação , Transdução de Sinais , Fator de Transcrição AP-1/genética , Células Tumorais CultivadasRESUMO
Abstract Pathway activity assessment-based approaches are becoming highly influential in various fields of biology and medicine. However, these approaches mostly rely on analysis of mRNA expression, and total mRNA from a given locus is measured in the majority of cases. Notably, a significant portion of protein-coding genes produces more than one transcript. This biological fact is responsible for significant noise when changes in total mRNA transcription of a single gene are analyzed. The NFE2L2/AP-1 pathway is an attractive target for biomedical applications. To date, there is a lack of data regarding the agreement in expression of even classical target genes of this pathway. In the present paper we analyzed whether transcript variants of GPX2, NQO1 and SQSTM1 were characterized by individual features of expression when HeLa cells were exposed to pro-oxidative stimulation with hydrogen peroxide. We found that all the transcripts (10 in total) appeared to be significantly individually regulated under the conditions tested. We conclude that individual transcripts, rather than total mRNA, are best markers of pathway activation. We also discuss here some biological roles of individual transcript regulation.
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The HIV accessory protein Nef is a major determinant of viral pathogenesis that facilitates viral particle release, prevents viral antigen presentation and increases infectivity of new virus particles. These functions of Nef involve its ability to remove specific host proteins from the surface of infected cells, including the CD4 receptor. Nef binds to the adaptor protein 2 (AP-2) and CD4 in clathrin-coated pits, forcing CD4 internalization and its subsequent targeting to lysosomes. Herein, we report that this lysosomal targeting requires a variant of AP-1 containing isoform 2 of γ-adaptin (AP1G2, hereafter γ2). Depletion of the γ2 or µ1A (AP1M1) subunits of AP-1, but not of γ1 (AP1G1), precludes Nef-mediated lysosomal degradation of CD4. In γ2-depleted cells, CD4 internalized by Nef accumulates in early endosomes and this alleviates CD4 removal from the cell surface. Depletion of γ2 also hinders EGFR-EGF-complex targeting to lysosomes, an effect that is not observed upon γ1 depletion. Taken together, our data provide evidence that the presence of γ1 or γ2 subunits delineates two distinct variants of AP-1 complexes, with different functions in protein sorting.
Assuntos
Subunidades gama do Complexo de Proteínas Adaptadoras/metabolismo , Antígenos CD4/metabolismo , Regulação para Baixo , HIV-1/metabolismo , Produtos do Gene nef do Vírus da Imunodeficiência Humana/metabolismo , Endocitose , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Endossomos/metabolismo , Fator de Crescimento Epidérmico/metabolismo , Receptores ErbB/metabolismo , Técnicas de Silenciamento de Genes , Proteínas de Fluorescência Verde/metabolismo , Células HeLa , Humanos , Lisossomos/metabolismo , Fosfoproteínas/metabolismo , Ligação Proteica , Transporte Proteico , Proteólise , Técnicas do Sistema de Duplo-HíbridoRESUMO
Reactive species play an important role in physiological functions. Overproduction of reactive species, notably reactive oxygen (ROS) and nitrogen (RNS) species along with the failure of balance by the body's antioxidant enzyme systems results in destruction of cellular structures, lipids, proteins, and genetic materials such as DNA and RNA. Moreover, the effects of reactive species on mitochondria and their metabolic processes eventually cause a rise in ROS/RNS levels, leading to oxidation of mitochondrial proteins, lipids, and DNA. Oxidative stress has been considered to be linked to the etiology of many diseases, including neurodegenerative diseases (NDDs) such as Alzheimer diseases, Amyotrophic lateral sclerosis, Friedreich's ataxia, Huntington's disease, Multiple sclerosis, and Parkinson's diseases. In addition, oxidative stress causing protein misfold may turn to other NDDs include Creutzfeldt-Jakob disease, Bovine Spongiform Encephalopathy, Kuru, Gerstmann-Straussler-Scheinker syndrome, and Fatal Familial Insomnia. An overview of the oxidative stress and mitochondrial dysfunction-linked NDDs has been summarized in this review.
Assuntos
Doenças Mitocondriais/etiologia , Doenças Neurodegenerativas/complicações , Estresse Oxidativo/fisiologia , Animais , HumanosRESUMO
Estrogen receptor α (ERα) exerts regulatory actions through genomic mechanisms. In the classical pathway, ligand-activated ERα binds directly to DNA through estrogen response elements (ERE) located in the promoter of target genes. ERα can also exert indirect regulation of transcription via protein-protein interaction with other transcription factors such as AP-1.S everal ERα synonymous polymorphisms have been identified and efforts to understand their implications have been made. Nevertheless effects of synonymous polymorphisms are still neglected. This chapter focuses on the experimental procedure employed in order to characterize the transcriptional activity of a synonymous polymorphism of the ERα (rs746432) called Alanine 87 (Ala87). Activity of both WT and Ala87 ERα isoforms on transcriptional pathways can be analyzed in transiently transfected cells using different reporter constructs. ERα efficiency on the classical genomic pathway can be analyzed by determining its transactivation activity on an ERE-driven thymidine kinase (TK) promoter controlling the expression of the luciferase reporter gene. Transcriptional activity through the indirect genomic pathway can be analyzed by employing an AP-1 DNA response element-driven promoter also controlling the expression of luciferase reporter gene.
Assuntos
Receptor alfa de Estrogênio/metabolismo , Mutação , Elementos de Resposta , Timidina Quinase/genética , Fator de Transcrição AP-1/metabolismo , Ativação Transcricional , Alanina , Receptor alfa de Estrogênio/genética , Regulação da Expressão Gênica , Genes Reporter , Células HeLa , Células Hep G2 , Humanos , Luciferases/genética , Luciferases/metabolismo , Ligação Proteica , Transcrição Gênica , Transfecção , Fluxo de TrabalhoRESUMO
In order to understand how fungal pathogens can survive inside the host, we must analyze how they evade the fungicidal mechanisms mounted by the host's immune system, such as generation of toxic reactive oxygen species. Studies have shown that infections caused by Sporothrix brasiliensis can be more aggressive than those due to Sporothrix schenckii. Therefore, we propose to analyze and compare the ability of these two pathogenic species to counteract oxidative stress, which, as noted, can be relevant in the host response to infection. We have shown that S. brasiliensis is more resistant to different oxidants, such as H2O2 and menadione, when compared with S. schenckii. Furthermore, our results suggest that the molecular mechanisms by which Sporothrix spp. AP-1 like transcription factors are regulated probably differs from the one seen in other fungal pathogens. Interestingly, comparison between sequences of SbHog1 and SsHog1 stress activated protein kinases suggest that S. brasiliensis Hog1 display mutations that could account for the differences seen in stress sensitivities of these two species. In summary, this is the first study to our knowledge to investigate oxidative stress responses of Sporothrix spp. and provided a model that can be employed in vivo to address how these fungal pathogens can surmount the oxidative stress generated by the host.