Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 6.736
Filtrar
1.
Nat Commun ; 11(1): 4755, 2020 09 21.
Artigo em Inglês | MEDLINE | ID: mdl-32958772

RESUMO

We hereby provide the initial portrait of lincNORS, a spliced lincRNA generated by the MIR193BHG locus, entirely distinct from the previously described miR-193b-365a tandem. While inducible by low O2 in a variety of cells and associated with hypoxia in vivo, our studies show that lincNORS is subject to multiple regulatory inputs, including estrogen signals. Biochemically, this lincRNA fine-tunes cellular sterol/steroid biosynthesis by repressing the expression of multiple pathway components. Mechanistically, the function of lincNORS requires the presence of RALY, an RNA-binding protein recently found to be implicated in cholesterol homeostasis. We also noticed the proximity between this locus and naturally occurring genetic variations highly significant for sterol/steroid-related phenotypes, in particular the age of sexual maturation. An integrative analysis of these variants provided a more formal link between these phenotypes and lincNORS, further strengthening the case for its biological relevance.


Assuntos
Homeostase , Oxigênio/metabolismo , RNA Longo não Codificante/fisiologia , Esteróis/biossíntese , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Hipóxia Celular , Linhagem Celular Tumoral , Núcleo Celular/metabolismo , Colesterol/metabolismo , Estrogênios/metabolismo , Regulação da Expressão Gênica , Estudo de Associação Genômica Ampla , Ribonucleoproteínas Nucleares Heterogêneas Grupo C/genética , Ribonucleoproteínas Nucleares Heterogêneas Grupo C/metabolismo , Humanos , Células MCF-7 , Fenótipo , Polimorfismo de Nucleotídeo Único , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismo
2.
Nat Commun ; 11(1): 4111, 2020 08 17.
Artigo em Inglês | MEDLINE | ID: mdl-32807776

RESUMO

Mutational inactivation of VHL is the earliest genetic event in the majority of clear cell renal cell carcinomas (ccRCC), leading to accumulation of the HIF-1α and HIF-2α transcription factors. While correlative studies of human ccRCC and functional studies using human ccRCC cell lines have implicated HIF-1α as an inhibitor and HIF-2α as a promoter of aggressive tumour behaviours, their roles in tumour onset have not been functionally addressed. Herein we show using an autochthonous ccRCC model that Hif1a is essential for tumour formation whereas Hif2a deletion has only minor effects on tumour initiation and growth. Both HIF-1α and HIF-2α are required for the clear cell phenotype. Transcriptomic and proteomic analyses reveal that HIF-1α regulates glycolysis while HIF-2α regulates genes associated with lipoprotein metabolism, ribosome biogenesis and E2F and MYC transcriptional activities. HIF-2α-deficient tumours are characterised by increased antigen presentation, interferon signalling and CD8+ T cell infiltration and activation. Single copy loss of HIF1A or high levels of HIF2A mRNA expression correlate with altered immune microenvironments in human ccRCC. These studies reveal an oncogenic role of HIF-1α in ccRCC initiation and suggest that alterations in the balance of HIF-1α and HIF-2α activities can affect different aspects of ccRCC biology and disease aggressiveness.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Carcinoma de Células Renais/metabolismo , Carcinoma de Células Renais/patologia , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Neoplasias Renais/metabolismo , Neoplasias Renais/patologia , Células 3T3 , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Western Blotting , Linfócitos T CD8-Positivos/metabolismo , Carcinoma de Células Renais/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , Proliferação de Células/fisiologia , Regulação Neoplásica da Expressão Gênica/genética , Regulação Neoplásica da Expressão Gênica/fisiologia , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Imuno-Histoquímica , Inflamação/genética , Inflamação/metabolismo , Neoplasias Renais/genética , Espectrometria de Massas , Camundongos , Proteômica/métodos , Reação em Cadeia da Polimerase em Tempo Real , Análise de Sequência de RNA , Microambiente Tumoral/genética , Microambiente Tumoral/fisiologia
3.
Mutat Res ; 785: 108319, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32800270

RESUMO

Cleft lip and palate (CL/P) is among the most common congenital malformations and affects 1 in 700 newborns. CL/P is caused by genetic and environmental factors (maternal smoking, alcohol or drug use and others). Many genes and loci were associated with cleft lip/palate but the amount of heterogeneity justifies identifying new causal genes and variants. AHRR (Aryl-Hydrocarbon Receptor Repressor) gene has recently been related to CL/P however, few functional studies analyze the genotypephenotype interaction of AHRR with CL/P. Several studies associate the molecular pathway of AHRR to CL/P which indicates this gene as a functional candidate in CL/P etiology. METHODS: Systematic Literature Review was performed using PUBMED database with the keywords cleft lip, cleft palate, orofacial cleft, AHRR and synonyms. SLR resulted in 37 included articles. RESULTS: AHRR is a positional and functional candidate gene for CL/P. In silico analysis detected interactions with other genes previously associated to CL/P like ARNT and CYP1A1. AHRR protein regulates cellular toxicity through TCDD mediated AHR pathway. Exposure to TCDD in animal embryos is AHR mediated and lead to cleft palate due to palate fusion failure and post fusion rupture. AHRR regulates cellular growth and differentiation, fundamental to lip and palatogenesis. AHRR decreases carcinogenesis and recently a higher tumor risk has been described in CL/P patients and families. AHRR is also a smoking biomarker due to changed methylation sites found in smokers DNA although folate intake may partially revert these methylation alterations. This corroborates the role of maternal smoking and lack of folate supplementation as risk factors for CL/P. CONCLUSION: This research identified the importance of AHRR in dioxin response and demonstrated an example of genetic and environmental interaction, indispensable in the development of many complex diseases.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fenda Labial/genética , Fissura Palatina/genética , Proteínas Repressoras/genética , Fumar/efeitos adversos , Motivos de Aminoácidos , Fatores de Transcrição Hélice-Alça-Hélice Básicos/química , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Biomarcadores/metabolismo , Metilação de DNA , Suplementos Nutricionais , Feminino , Ácido Fólico/metabolismo , Estudos de Associação Genética , Humanos , Recém-Nascido , Masculino , Modelos Moleculares , Domínios Proteicos , Isoformas de RNA/genética , Proteínas Repressoras/química , Proteínas Repressoras/metabolismo , Fatores de Risco
4.
Nat Commun ; 11(1): 4214, 2020 08 25.
Artigo em Inglês | MEDLINE | ID: mdl-32843632

RESUMO

Stomata are epidermal structures that modulate gas exchanges between plants and the atmosphere. The formation of stomata is regulated by multiple developmental and environmental signals, but how these signals are coordinated to control this process remains unclear. Here, we showed that the conserved energy sensor kinase SnRK1 promotes stomatal development under short-day photoperiod or in liquid culture conditions. Mutation of KIN10, the catalytic α-subunit of SnRK1, results in the decreased stomatal index; while overexpression of KIN10 significantly induces stomatal development. KIN10 displays the cell-type-specific subcellular location pattern. The nuclear-localized KIN10 proteins are highly enriched in the stomatal lineage cells to phosphorylate and stabilize SPEECHLESS, a master regulator of stomatal formation, thereby promoting stomatal development. Our work identifies a module links connecting the energy signaling and stomatal development and reveals that multiple regulatory mechanisms are in place for SnRK1 to modulate stomatal development in response to changing environments.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Estômatos de Plantas/genética , Fatores de Transcrição/genética , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Regulação da Expressão Gênica de Plantas , Proteínas de Fluorescência Verde/genética , Proteínas de Fluorescência Verde/metabolismo , Microscopia Confocal , Mutação , Fosforilação , Fotoperíodo , Estômatos de Plantas/citologia , Estômatos de Plantas/metabolismo , Plantas Geneticamente Modificadas , Estabilidade Proteica , Proteínas Serina-Treonina Quinases/genética , Proteínas Serina-Treonina Quinases/metabolismo , Transdução de Sinais/genética , Fatores de Transcrição/metabolismo
5.
Proc Natl Acad Sci U S A ; 117(35): 21441-21449, 2020 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-32817424

RESUMO

Loss of the von Hippel-Lindau (VHL) tumor suppressor is a hallmark feature of renal clear cell carcinoma. VHL inactivation results in the constitutive activation of the hypoxia-inducible factors (HIFs) HIF-1 and HIF-2 and their downstream targets, including the proangiogenic factors VEGF and PDGF. However, antiangiogenic agents and HIF-2 inhibitors have limited efficacy in cancer therapy due to the development of resistance. Here we employed an innovative computational platform, Mining of Synthetic Lethals (MiSL), to identify synthetic lethal interactions with the loss of VHL through analysis of primary tumor genomic and transcriptomic data. Using this approach, we identified a synthetic lethal interaction between VHL and the m6A RNA demethylase FTO in renal cell carcinoma. MiSL identified FTO as a synthetic lethal partner of VHL because deletions of FTO are mutually exclusive with VHL loss in pan cancer datasets. Moreover, FTO expression is increased in VHL-deficient ccRCC tumors compared to normal adjacent tissue. Genetic inactivation of FTO using multiple orthogonal approaches revealed that FTO inhibition selectively reduces the growth and survival of VHL-deficient cells in vitro and in vivo. Notably, FTO inhibition reduced the survival of both HIF wild type and HIF-deficient tumors, identifying FTO as an HIF-independent vulnerability of VHL-deficient cancers. Integrated analysis of transcriptome-wide m6A-seq and mRNA-seq analysis identified the glutamine transporter SLC1A5 as an FTO target that promotes metabolic reprogramming and survival of VHL-deficient ccRCC cells. These findings identify FTO as a potential HIF-independent therapeutic target for the treatment of VHL-deficient renal cell carcinoma.


Assuntos
Dioxigenase FTO Dependente de alfa-Cetoglutarato/genética , Carcinoma de Células Renais/genética , Neoplasias Renais/genética , Mutações Sintéticas Letais , Proteína Supressora de Tumor Von Hippel-Lindau/genética , Dioxigenase FTO Dependente de alfa-Cetoglutarato/metabolismo , Sistema ASC de Transporte de Aminoácidos/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Carcinoma de Células Renais/metabolismo , Linhagem Celular Tumoral , Simulação por Computador , Humanos , Fator 1 Induzível por Hipóxia/metabolismo , Neoplasias Renais/metabolismo , Camundongos Knockout , Antígenos de Histocompatibilidade Menor/metabolismo
6.
PLoS Pathog ; 16(7): e1008664, 2020 07.
Artigo em Inglês | MEDLINE | ID: mdl-32678826

RESUMO

Establishing latent infection but retaining the capability to reactivate in certain circumstance is an ingenious tactic for retroviruses to persist in vivo while evading host immune surveillance. Many evidences indicate that Human T-cell leukemia virus type 1 (HTLV-1) is not completely silent in vivo. However, signals that trigger HTLV-1 latency-reactivation switching remain poorly understood. Here, we show that aryl hydrocarbon receptor (AHR), a ligand-activated transcription factor, plays a critical role in HTLV-1 plus-strand expression. Importantly, HTLV-1 reactivation could be tunably manipulated by modulating the level of AHR ligands. Mechanistically, activated AHR binds to HTLV-1 LTR dioxin response element (DRE) site (CACGCATAT) and drives plus-strand transcription. On the other hand, persistent activation of nuclear factor kappa B (NF-κB) pathway constitutes one key prerequisite for AHR overexpression in HTLV-1 infected T-cells, setting the stage for the advent of AHR signaling. Our findings suggest that HTLV-1 might achieve its reactivation in vivo when encountering environmental, dietary, microbial and metabolic cues that induce sufficient AHR signaling.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Infecções por HTLV-I/virologia , Vírus Linfotrópico T Tipo 1 Humano/metabolismo , Receptores de Hidrocarboneto Arílico/metabolismo , Ativação Viral/fisiologia , Latência Viral/fisiologia , Linhagem Celular , Infecções por HTLV-I/metabolismo , Humanos , Linfócitos T/virologia
7.
PLoS One ; 15(7): e0235922, 2020.
Artigo em Inglês | MEDLINE | ID: mdl-32673370

RESUMO

We have previously established that epigenetic regulator RING1 and YY1 binding protein (RYBP) is required for the contractility of embryonic stem (ES) cell derived cardiomyocytes (CMCs), suggesting its essential role in contractility. In order to investigate the underlying molecular events of this phenotype, we compared the transcriptomic profile of the wild type and Rybp null mutant ES cells and CMCs differentiated from these cell lines. We identified genes related to ion homeostasis, cell adhesion and sarcomeric organization affected in the Rybp null mutant CMCs, by using hierarchical gene clustering and Gene Ontology analysis. We have also demonstrated that the amount of RYBP is drastically reduced in the terminally differentiated wild type CMCs whilst it is broadly expressed in the early phase of differentiation when progenitors form. We also describe that RYBP is important for the proper expression of key cardiac transcription factors including Mesp1, Shh and Mef2c. These findings identify Rybp as a gene important for both early cardiac gene transcription and consequent sarcomere formation necessary for contractility. Since impairment of sarcomeric function and contractility plays a central role in reduced cardiac pump function leading to heart failures in human, current results might be relevant to the pathophysiology of cardiomyopathies.


Assuntos
Proteínas Repressoras/genética , Sarcômeros/fisiologia , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Moléculas de Adesão Celular/genética , Moléculas de Adesão Celular/metabolismo , Diferenciação Celular , Linhagem Celular , Regulação da Expressão Gênica no Desenvolvimento , Proteínas Hedgehog/genética , Proteínas Hedgehog/metabolismo , Canais Iônicos/genética , Canais Iônicos/metabolismo , Camundongos , Células-Tronco Embrionárias Murinas/citologia , Células-Tronco Embrionárias Murinas/metabolismo , Miócitos Cardíacos/citologia , Miócitos Cardíacos/metabolismo , RNA Mensageiro/metabolismo , Proteínas Repressoras/deficiência
8.
Proc Natl Acad Sci U S A ; 117(31): 18840-18848, 2020 08 04.
Artigo em Inglês | MEDLINE | ID: mdl-32690706

RESUMO

Light and gravity are two key environmental factors that control plant growth and architecture. However, the molecular basis of the coordination of light and gravity signaling in plants remains obscure. Here, we report that two classes of transcription factors, PHYTOCHROME INTERACTING FACTORS (PIFs) and ELONGATED HYPOCOTYL5 (HY5), can directly bind and activate the expression of LAZY4, a positive regulator of gravitropism in both shoots and roots in Arabidopsis In hypocotyls, light promotes degradation of PIFs to reduce LAZY4 expression, which inhibits the negative gravitropism of hypocotyls. LAZY4 overexpression can partially rescue the negative gravitropic phenotype of pifq in the dark without affecting amyloplast development. Our identification of the PIFs-LAZY4 regulatory module suggests the presence of another role for PIF proteins in gravitropism, in addition to a previous report demonstrating that PIFs positively regulate amyloplast development to promote negative gravitropism in hypocotyls. In roots, light promotes accumulation of HY5 proteins to activate expression of LAZY4, which promotes positive gravitropism in roots. Together, our data indicate that light exerts opposite regulation of LAZY4 expression in shoots and roots by mediating the protein levels of PIFs and HY5, respectively, to inhibit the negative gravitropism of shoots and promote positive gravitropism of roots in Arabidopsis.


Assuntos
Proteínas de Arabidopsis , Fatores de Transcrição Hélice-Alça-Hélice Básicos , Fatores de Transcrição de Zíper de Leucina Básica , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Gravitropismo/efeitos da radiação , Proteínas Nucleares , Arabidopsis/genética , Arabidopsis/metabolismo , Arabidopsis/efeitos da radiação , Proteínas de Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Fatores de Transcrição de Zíper de Leucina Básica/genética , Fatores de Transcrição de Zíper de Leucina Básica/metabolismo , Luz , Proteínas Nucleares/genética , Proteínas Nucleares/metabolismo
9.
Proc Natl Acad Sci U S A ; 117(32): 19376-19387, 2020 08 11.
Artigo em Inglês | MEDLINE | ID: mdl-32719140

RESUMO

Inflammatory bowel diseases (IBDs), including Crohn's disease and ulcerative colitis, are associated with dysbiosis of the gut microbiome. Emerging evidence suggests that small-molecule metabolites derived from bacterial breakdown of a variety of dietary nutrients confer a wide array of host benefits, including amelioration of inflammation in IBDs. Yet, in many cases, the molecular pathways targeted by these molecules remain unknown. Here, we describe roles for three metabolites-indole-3-ethanol, indole-3-pyruvate, and indole-3-aldehyde-which are derived from gut bacterial metabolism of the essential amino acid tryptophan, in regulating intestinal barrier function. We determined that these metabolites protect against increased gut permeability associated with a mouse model of colitis by maintaining the integrity of the apical junctional complex and its associated actin regulatory proteins, including myosin IIA and ezrin, and that these effects are dependent on the aryl hydrocarbon receptor. Our studies provide a deeper understanding of how gut microbial metabolites affect host defense mechanisms and identify candidate pathways for prophylactic and therapeutic treatments for IBDs.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Microbioma Gastrointestinal/fisiologia , Mucosa Intestinal/metabolismo , Mucosa Intestinal/microbiologia , Receptores de Hidrocarboneto Arílico/metabolismo , Triptofano/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Células CACO-2 , Colite Ulcerativa/dietoterapia , Colite Ulcerativa/microbiologia , Colite Ulcerativa/patologia , Proteínas do Citoesqueleto/genética , Proteínas do Citoesqueleto/metabolismo , Modelos Animais de Doenças , Humanos , Inflamação , Mucosa Intestinal/patologia , Camundongos , Camundongos Knockout , Miosina não Muscular Tipo IIA/metabolismo , Permeabilidade , Receptores de Hidrocarboneto Arílico/genética , Triptofano/administração & dosagem
10.
Rev Cardiovasc Med ; 21(2): 253-261, 2020 Jun 30.
Artigo em Inglês | MEDLINE | ID: mdl-32706213

RESUMO

It is known that functional defects of GATA binding protein 5 (GATA5), an important member of GATA transcription factor family, could cause multiple congenital defects. However, the mechanisms of this transcription factor in cardiovascular diseases are still little known. Finding a genetic approach should help with understanding the possible roles of GATA5 in different cardiovascular diseases and purpose it as a possible therapeutic agent. Hence, this review is divided into three chapters to summarize the roles and main regulatory mechanisms of GATA5 in hypertension, arrhythmia and congenital heart disease, respectively. In each chapter, this review firstly introduces the roles of GATA5 mutations, and then discusses the main regulatory mechanisms of GATA5 in the corresponding diseases (Such as the endothelial dysfunction signaling pathway in the chapter of hypertension, GATA5-NaV1.5 signaling pathway in the chapter of arrhythmia, GATA5-HEY2 and GATA5-Nodal signaling pathway in the chapter of congenital heart disease). Additionally, based on these regulatory networks, it is also speculated that abnormal methylation of the GATA5 gene promoter may lead to cardiovascular diseases such as congenital heart disease. This conjecture is proposed to enrich the regulatory networks of GATA5 and provide a theoretical basis for diagnosis and treatment of cardiovascular diseases.


Assuntos
Doenças Cardiovasculares/metabolismo , Sistema Cardiovascular/metabolismo , Fator de Transcrição GATA5/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Doenças Cardiovasculares/genética , Doenças Cardiovasculares/fisiopatologia , Sistema Cardiovascular/fisiopatologia , Fator de Transcrição GATA5/genética , Redes Reguladoras de Genes , Predisposição Genética para Doença , Humanos , Mutação , Canal de Sódio Disparado por Voltagem NAV1.5/genética , Canal de Sódio Disparado por Voltagem NAV1.5/metabolismo , Proteínas Repressoras/genética , Proteínas Repressoras/metabolismo , Transdução de Sinais
11.
Biol Res ; 53(1): 25, 2020 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-32503642

RESUMO

BACKGROUND: Hypoxia inducible factor-1 (HIF-1) is considered as the most activated transcriptional factor in response to low oxygen level or hypoxia. HIF-1 binds the hypoxia response element (HRE) sequence in the promoter of different genes, mainly through the bHLH domain and activates the transcription of genes, especially those involved in angiogenesis and EMT. Considering the critical role of bHLH in binding HIF-1 to the HRE sequence, we hypothesized that bHLH could be a promising candidate to be targeted in hypoxia condition. METHODS: We inserted an inhibitory bHLH (ibHLH) domain in a pIRES2-EGFP vector and transfected HEK293T cells with either the control vector or the designed construct. The ibHLH domain consisted of bHLH domains of both HIF-1a and Arnt, capable of competing with HIF-1 in binding to HRE sequences. The transfected cells were then treated with 200 µM of cobalt chloride (CoCl2) for 48 h to induce hypoxia. Real-time PCR and western blot were performed to evaluate the effect of ibHLH on the genes and proteins involved in angiogenesis and EMT. RESULTS: Hypoxia was successfully induced in the HEK293T cell line as the gene expression of VEGF, vimentin, and ß-catenin were significantly increased after treatment of untransfected HEK293T cells with 200 µM CoCl2. The gene expression of VEGF, vimentin, and ß-catenin and protein level of ß-catenin were significantly decreased in the cells transfected with either control or ibHLH vectors in hypoxia. However, ibHLH failed to be effective on these genes and the protein level of ß-catenin, when compared to the control vector. We also observed that overexpression of ibHLH had more inhibitory effect on gene and protein expression of N-cadherin compared to the control vector. However, it was not statistically significant. CONCLUSION: bHLH has been reported to be an important domain involved in the DNA binding activity of HIF. However, we found that targeting this domain is not sufficient to inhibit the endogenous HIF-1 transcriptional activity. Further studies about the function of critical domains of HIF-1 are necessary for developing a specific HIF-1 inhibitor.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Fator 1 Induzível por Hipóxia/metabolismo , Hipóxia/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Western Blotting , Expressão Gênica , Células HEK293 , Humanos , Hipóxia/genética , Fator 1 Induzível por Hipóxia/genética , Reação em Cadeia da Polimerase em Tempo Real , Ativação Transcricional/genética
12.
Proc Natl Acad Sci U S A ; 117(25): 14532-14542, 2020 06 23.
Artigo em Inglês | MEDLINE | ID: mdl-32513733

RESUMO

Implantation is initiated when an embryo attaches to the uterine luminal epithelium and subsequently penetrates into the underlying stroma to firmly embed in the endometrium. These events are followed by the formation of an extensive vascular network in the stroma that supports embryonic growth and ensures successful implantation. Interestingly, in many mammalian species, these processes of early pregnancy occur in a hypoxic environment. However, the mechanisms underlying maternal adaptation to hypoxia during early pregnancy remain unclear. In this study, using a knockout mouse model, we show that the transcription factor hypoxia-inducible factor 2 alpha (Hif2α), which is induced in subluminal stromal cells at the time of implantation, plays a crucial role during early pregnancy. Indeed, when preimplantation endometrial stromal cells are exposed to hypoxic conditions in vitro, we observed a striking enhancement in HIF2α expression. Further studies revealed that HIF2α regulates the expression of several metabolic and protein trafficking factors, including RAB27B, at the onset of implantation. RAB27B is a member of the Rab family of GTPases that allows controlled release of secretory granules. These granules are involved in trafficking MMP-9 from the stroma to the epithelium to promote luminal epithelial remodeling during embryo invasion. As pregnancy progresses, the HIF2α-RAB27B pathway additionally mediates crosstalk between stromal and endothelial cells via VEGF granules, developing the vascular network critical for establishing pregnancy. Collectively, our study provides insights into the intercellular communication mechanisms that operate during adaptation to hypoxia, which is essential for embryo implantation and establishment of pregnancy.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Hipóxia Celular/fisiologia , Implantação do Embrião/fisiologia , Vesículas Secretórias/metabolismo , Proteínas rab de Ligação ao GTP/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Comunicação Celular/fisiologia , Linhagem Celular , Embrião de Mamíferos , Endométrio/citologia , Endométrio/metabolismo , Feminino , Técnicas de Introdução de Genes , Humanos , Masculino , Camundongos , Camundongos Knockout , Gravidez , Interferência de RNA , RNA Interferente Pequeno/metabolismo , Transdução de Sinais/fisiologia , Células Estromais , Proteínas rab de Ligação ao GTP/genética
13.
Toxicol Appl Pharmacol ; 401: 115093, 2020 08 15.
Artigo em Inglês | MEDLINE | ID: mdl-32526215

RESUMO

Breast cancer incidence is increasing globally and pesticides exposure may impact risk of developing this disease. Hexachlorobenzene (HCB) and chlorpyrifos (CPF) act as endocrine disruptors, inducing proliferation in breast cancer cells. Vascular endothelial growth factor-A (VEGF-A), cyclooxygenase-2 (COX-2) and nitric oxide (NO) are associated with angiogenesis. Our aim was to evaluate HCB and CPF action, both weak aryl hydrocarbon receptor (AhR) ligands, on angiogenesis in breast cancer models. We used: (1) in vivo xenograft model with MCF-7 cells, (2) in vitro breast cancer model with MCF-7, and (3) in vitro neovasculogenesis model with endothelial cells exposed to conditioned medium from MCF-7. Results show that HCB (3 mg/kg) and CPF (0.1 mg/kg) stimulated vascular density in the in vivo model. HCB and CPF low doses enhanced VEGF-A and COX-2 expression, accompanied by increased levels of nitric oxide synthases (NOS), and NO release in MCF-7. HCB and CPF high doses intensified VEGF-A and COX-2 levels but rendered different effects on NOS, however, both pesticides reduced NO production. Moreover, our data indicate that HCB and CPF-induced VEGF-A expression is mediated by estrogen receptor and NO, while the increase in COX-2 is through AhR and NO pathways in MCF-7. In conclusion, we demonstrate that HCB and CPF environmental concentrations stimulate angiogenic switch in vivo. Besides, pesticides induce VEGF-A and COX-2 expression, as well as NO production in MCF-7, promoting tubulogenesis in endothelial cells. These findings show that pesticide exposure could stimulate angiogenesis, a process that has been demonstrated to contribute to breast cancer progression.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Clorpirifos/metabolismo , Hexaclorobenzeno/metabolismo , Neovascularização Patológica/induzido quimicamente , Neovascularização Patológica/metabolismo , Receptores de Hidrocarboneto Arílico/metabolismo , Células A549 , Animais , Clorpirifos/toxicidade , Relação Dose-Resposta a Droga , Feminino , Fungicidas Industriais/metabolismo , Fungicidas Industriais/toxicidade , Hexaclorobenzeno/toxicidade , Humanos , Inseticidas/metabolismo , Inseticidas/toxicidade , Ligantes , Células MCF-7 , Camundongos , Camundongos Nus , Transdução de Sinais/efeitos dos fármacos , Transdução de Sinais/fisiologia , Ensaios Antitumorais Modelo de Xenoenxerto/métodos
14.
Anat Sci Int ; 95(4): 523-539, 2020 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-32476103

RESUMO

Type 1 diabetes mellitus (T1DM) is a chronic metabolic disease caused by the destruction of pancreatic ß-cells. Human dental pulp stem cells represent a promising source for cell-based therapies, owing to their easy, minimally invasive surgical access, and high proliferative capacity. It was reported that human dental pulp stem cells can differentiate into a pancreatic cell lineage in vitro; however, few studies have investigated their effects on diabetes. Our study aimed to investigate the therapeutic potential of intravenous and intrapancreatic transplantation of human dental pulp stem cells in a rat model of streptozotocin-induced type 1 diabetes. Forty Sprague Dawley male rats were randomly categorized into four groups: control, diabetic (STZ), intravenous treatment group (IV), and intrapancreatic treatment group (IP). Human dental pulp stem cells (1 × 106 cells) or vehicle were injected into the pancreas or tail vein 7 days after streptozotocin injection. Fasting blood glucose levels were monitored weekly. Glucose tolerance test, rat and human serum insulin and C-peptide, pancreas histology, and caspase-3, vascular endothelial growth factor, and Ki67 expression in pancreatic tissues were assessed 28 days post-transplantation. We found that both IV and IP transplantation of human dental pulp stem cells reduced blood glucose and increased levels of rat and human serum insulin and C-peptide. The cells engrafted and survived in the streptozotocin-injured pancreas. Islet-like clusters and scattered human dental pulp stem cells expressing insulin were observed in the pancreas of diabetic rats with some difference in the distribution pattern between the two injection routes. RT-PCR analyses revealed the expression of the human-specific pancreatic ß-cell genes neurogenin 3 (NGN3), paired box 4 (PAX4), glucose transporter 2 (GLUT2), and insulin in the pancreatic tissues of both the IP and IV groups. In addition, the transplanted cells downregulated the expression of caspase-3 and upregulated the expression of vascular endothelial growth factor and Ki67, suggesting that the injected cells exerted pro-angiogenetic and antiapoptotic effects, and promoted endogenous ß-cell replication. Our study is the first to show that human dental pulp stem cells can migrate and survive within streptozotocin-injured pancreas, and induce antidiabetic effects through the differentiation and replacement of lost ß-cells and paracrine-mediated pancreatic regeneration. Thus, human dental pulp stem cells may have therapeutic potential to treat patients with long term T1DM.


Assuntos
Polpa Dentária/citologia , Diabetes Mellitus Experimental/terapia , Diabetes Mellitus Tipo 1/terapia , Pâncreas/fisiologia , Transplante de Células-Tronco , Células-Tronco/fisiologia , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Caspase 3/metabolismo , Diferenciação Celular , Movimento Celular , Sobrevivência Celular , Modelos Animais de Doenças , Transportador de Glucose Tipo 2/metabolismo , Proteínas de Homeodomínio/metabolismo , Humanos , Antígeno Ki-67/metabolismo , Masculino , Proteínas do Tecido Nervoso/metabolismo , Fatores de Transcrição Box Pareados/metabolismo , Pâncreas/citologia , Pâncreas/metabolismo , Ratos , Ratos Sprague-Dawley , Regeneração , Estreptozocina
15.
Mutat Res ; 853: 503173, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32522345

RESUMO

The aryl hydrocarbon receptor (AhR) transcription factor is activated by polycyclic aromatic hydrocarbons (PAH) and other ligands. Activated AhR binds to dioxin responsive elements (DRE) and initiates transcription of target genes, including the gene encoding prostaglandin endoperoxide synthase 2 (PTGS-2), which is also activated by the transcription factor NF-ĸB. PTGS-2 catalyzes the conversion of arachidonic acid (AA) into prostaglandins, thromboxanes or isoprostanes. 15-F2t-Isoprostane (IsoP), regarded as a universal marker of lipid peroxidation, is also induced by PAH exposure. We investigated the processes associated with lipid peroxidation in human alveolar basal epithelial cells (A549) exposed for 4 h or 24 h to model PAH (benzo[a]pyrene, BaP; 3-nitrobenzanthrone, 3-NBA) and organic extracts from ambient air particulate matter (EOM), collected in two seasons in a polluted locality. Both EOM induced the expression of CYP1A1 and CYP1B1; 24 h treatment significantly reduced PTGS-2 expression. IsoP levels decreased after both exposure periods, while the concentration of AA was not affected. The effects induced by BaP were similar to EOM except for increased IsoP levels after 4 h exposure and elevated AA concentration after 24 h treatment. In contrast, 3-NBA treatment did not induce CYP expression, had a weak effect on PTGS-2 expression, and, similar to BaP, induced IsoP levels after 4 h exposure and AA levels after 24 h treatment. All tested compounds induced the activity of NF-ĸB after the longer exposure period. In summary, our data suggest that EOM, and partly BaP, reduce lipid peroxidation by a mechanism that involves AhR-dependent inhibition of PTGS-2 expression. The effect of 3-NBA on IsoP levels is probably mediated by a different mechanism independent of AhR activation.


Assuntos
Células Epiteliais Alveolares/efeitos dos fármacos , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Peroxidação de Lipídeos/efeitos dos fármacos , Mutagênicos/toxicidade , Receptores de Hidrocarboneto Arílico/metabolismo , Células A549 , Benzo(a)Antracenos/toxicidade , Benzo(a)pireno/toxicidade , Linhagem Celular Tumoral , Ciclo-Oxigenase 1/metabolismo , Citocromo P-450 CYP1A1/metabolismo , Humanos , NF-kappa B/metabolismo , Material Particulado/toxicidade , Hidrocarbonetos Policíclicos Aromáticos/toxicidade
16.
Proc Natl Acad Sci U S A ; 117(26): 15075-15084, 2020 06 30.
Artigo em Inglês | MEDLINE | ID: mdl-32532919

RESUMO

Some lineage-determining transcription factors are overwhelmingly important in directing embryonic cells to a particular differentiation pathway, such as Ascl1 for nerve. They also have an exceptionally strong ability to force cells to change from an unrelated pathway to one preferred by their action. Transcription factors are believed to have a very short residence time of only a few seconds on their specific DNA or chromatin-binding sites. We have developed a procedure in which DNA containing one copy of the binding site for the neural-inducing factor Ascl1 is injected directly into a Xenopus oocyte nucleus which has been preloaded with a limiting amount of the Ascl1 transcription factor protein. This is followed by a further injection of DNA as a competitor, either in a plasmid or in chromosomal DNA, containing the same binding site but with a different reporter. Importantly, expression of the reporter provides a measure of the function of the transcription factor in addition to its residence time. The same long residence time and resistance to competition are seen with the estrogen receptor and its DNA response elements. We find that in this nondividing oocyte, the nerve-inducing factor Ascl1 can remain bound to a specific chromatin site for hours or days and thereby help to stabilize gene expression. This stability of transcription factor binding to chromatin is a necessary part of its action because removal of this factor causes discontinuation of its effect on gene expression. Stable transcription factor binding may be a characteristic of nondividing cells.


Assuntos
Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Cromatina/metabolismo , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Sítios de Ligação , Cromatina/genética , DNA/genética , DNA/metabolismo , Regulação da Expressão Gênica no Desenvolvimento , Oócitos/crescimento & desenvolvimento , Oócitos/metabolismo , Ligação Proteica , Xenopus laevis/embriologia , Xenopus laevis/genética , Xenopus laevis/metabolismo
17.
Chemosphere ; 258: 127332, 2020 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-32554009

RESUMO

Prioritizing chemicals posing threats to drinking water resources is crucial for legislation considering the cost of water treatment, remediation, and monitoring. We profiled in vitro potential endocrine disrupting activities (both agonistic and antagonistic) of 18 contaminants most prevalent in Walloon raw water resources intended for drinking water production, including several compound groups: pesticides, perfluorinated compounds, polycyclic aromatic hydrocarbons, a corrosion inhibitor, and bisphenol A. Mixtures thereof relevant for human realistic exposure were also investigated. Seven luciferase reporter gene cell lines were used i.e. three (human and rat) responsive to dioxins through the aryl hydrocarbon receptor (AhR) and four (human) responsive to steroids through the estrogen (ER), androgen (AR), progesterone (PR), and glucocorticoid (GR) receptors. Among the 18 compounds, ten caused at least one response in at least one receptor. Specifically, chlorpyrifos, bisphenol A, fluoranthene, phenanthrene, and benzo [a]pyrene displayed significant activities on several receptors. Bisphenol A agonized ER, but abolished the cells' response to androgen and progesterone. While fluoranthene and phenanthrene strongly reduced human AhR and AR transactivation, benzo [a]pyrene strongly activated AhR and ER, but inhibited GR and AR. In human breast cancer cells, benzo [a]pyrene dramatically activated AhR, inducing a 10-fold higher response than 2,3,7,8-tetrachlorodibenzodioxin (TCDD) at concentrations possibly found realistically in human blood. The mixture of the 18 compounds exerted both ER and rat AhR agonism, with the main contribution being from benzo [a]pyrene or its combination with bisphenol A. Moreover, the mixture significantly inhibited TCDD-induced CYP1A activity (detected only by EROD assays) in human hepatoma cells.


Assuntos
Água Potável/química , Disruptores Endócrinos/análise , Poluentes Químicos da Água/análise , Animais , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Compostos Benzidrílicos , Benzo(a)pireno/metabolismo , Estrogênios , Genes Reporter , Humanos , Praguicidas , Fenóis , Dibenzodioxinas Policloradas , Hidrocarbonetos Policíclicos Aromáticos/metabolismo , Ratos , Receptores de Hidrocarboneto Arílico/metabolismo , Recursos Hídricos
18.
Nature ; 581(7806): 83-88, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32376950

RESUMO

Photoreceptor loss is the final common endpoint in most retinopathies that lead to irreversible blindness, and there are no effective treatments to restore vision1,2. Chemical reprogramming of fibroblasts offers an opportunity to reverse vision loss; however, the generation of sensory neuronal subtypes such as photoreceptors remains a challenge. Here we report that the administration of a set of five small molecules can chemically induce the transformation of fibroblasts into rod photoreceptor-like cells. The transplantation of these chemically induced photoreceptor-like cells (CiPCs) into the subretinal space of rod degeneration mice (homozygous for rd1, also known as Pde6b) leads to partial restoration of the pupil reflex and visual function. We show that mitonuclear communication is a key determining factor for the reprogramming of fibroblasts into CiPCs. Specifically, treatment with these five compounds leads to the translocation of AXIN2 to the mitochondria, which results in the production of reactive oxygen species, the activation of NF-κB and the upregulation of Ascl1. We anticipate that CiPCs could have therapeutic potential for restoring vision.


Assuntos
Reprogramação Celular/efeitos dos fármacos , Fibroblastos/citologia , Fibroblastos/efeitos dos fármacos , Degeneração Retiniana/terapia , Células Fotorreceptoras Retinianas Bastonetes/citologia , Células Fotorreceptoras Retinianas Bastonetes/transplante , Visão Ocular/efeitos dos fármacos , Animais , Proteína Axina/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Modelos Animais de Doenças , Citometria de Fluxo , Camundongos , Mitocôndrias/efeitos dos fármacos , Mitocôndrias/metabolismo , NF-kappa B/metabolismo , Transporte Proteico/efeitos dos fármacos , Espécies Reativas de Oxigênio/metabolismo , Degeneração Retiniana/patologia , Células Fotorreceptoras Retinianas Bastonetes/efeitos dos fármacos , Transdução de Sinais/efeitos dos fármacos , Visão Ocular/fisiologia
19.
PLoS Genet ; 16(5): e1008797, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32392219

RESUMO

Sun-loving plants perceive the proximity of potential light-competing neighboring plants as a reduction in the red:far-red ratio (R:FR), which elicits a suite of responses called the "shade avoidance syndrome" (SAS). Changes in R:FR are primarily perceived by phytochrome B (phyB), whereas UV-B perceived by UV RESISTANCE LOCUS 8 (UVR8) elicits opposing responses to provide a counterbalance to SAS, including reduced shade-induced hypocotyl and petiole elongation. Here we show at the genome-wide level that UVR8 broadly suppresses shade-induced gene expression. A subset of this gene regulation is dependent on the UVR8-stabilized atypical bHLH transcription regulator LONG HYPOCOTYL IN FAR-RED 1 (HFR1), which functions in part redundantly with PHYTOCHROME INTERACTING FACTOR 3-LIKE 1 (PIL1). In parallel, UVR8 signaling decreases protein levels of the key positive regulators of SAS, namely the bHLH transcription factors PHYTOCHROME INTERACTING FACTOR 4 (PIF4) and PIF5, in a COP1-dependent but HFR1-independent manner. We propose that UV-B antagonizes SAS via two mechanisms: degradation of PIF4 and PIF5, and HFR1- and PIL1-mediated inhibition of PIF4 and PIF5 function. This work highlights the importance of typical and atypical bHLH transcription regulators for the integration of light signals from different photoreceptors and provides further mechanistic insight into the crosstalk of UVR8 signaling and SAS.


Assuntos
Proteínas de Arabidopsis/química , Proteínas de Arabidopsis/genética , Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/química , Proteínas Cromossômicas não Histona/genética , Proteínas de Ligação a DNA/química , Raios Ultravioleta/efeitos adversos , Arabidopsis/efeitos dos fármacos , Arabidopsis/genética , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Cromatina/metabolismo , Proteínas Cromossômicas não Histona/metabolismo , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Regulação para Baixo , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Estabilidade Proteica , Proteólise , Fatores de Transcrição/genética , Fatores de Transcrição/metabolismo , Ubiquitina-Proteína Ligases/genética , Ubiquitina-Proteína Ligases/metabolismo
20.
PLoS Genet ; 16(5): e1008807, 2020 05.
Artigo em Inglês | MEDLINE | ID: mdl-32407354

RESUMO

Pollen wall consists of several complex layers which form elaborate species-specific patterns. In Arabidopsis, the transcription factor ABORTED MICROSPORE (AMS) is a master regulator of exine formation, and another transcription factor, TRANSPOSABLE ELEMENT SILENCING VIA AT-HOOK (TEK), specifies formation of the nexine layer. However, knowledge regarding the temporal regulatory roles of TEK in pollen wall development is limited. Here, TEK-GFP driven by the AMS promoter was prematurely expressed in the tapetal nuclei, leading to complete male sterility in the pAMS:TEK-GFP (pat) transgenic lines with the wild-type background. Cytological observations in the pat anthers showed impaired callose synthesis and aberrant exine patterning. CALLOSE SYNTHASE5 (CalS5) is required for callose synthesis, and expression of CalS5 in pat plants was significantly reduced. We demonstrated that TEK negatively regulates CalS5 expression after the tetrad stage in wild-type anthers and further discovered that premature TEK-GFP in pat directly represses CalS5 expression through histone modification. Our findings show that TEK flexibly mediates its different functions via different temporal regulation, revealing that the temporal regulation of TEK is essential for exine patterning. Moreover, the result that the repression of CalS5 by TEK after the tetrad stage coincides with the timing of callose wall dissolution suggests that tapetum utilizes temporal regulation of genes to stop callose wall synthesis, which, together with the activation of callase activity, achieves microspore release and pollen wall patterning.


Assuntos
Proteínas de Arabidopsis/genética , Arabidopsis/genética , Fatores de Transcrição Hélice-Alça-Hélice Básicos/genética , Pólen/fisiologia , Fatores de Transcrição/metabolismo , Arabidopsis/fisiologia , Proteínas de Arabidopsis/metabolismo , Fatores de Transcrição Hélice-Alça-Hélice Básicos/metabolismo , Epigênese Genética , Regulação da Expressão Gênica de Plantas , Glucosiltransferases/metabolismo , Histonas/metabolismo , Metilação , Plantas Geneticamente Modificadas/fisiologia , Pólen/genética , Regiões Promotoras Genéticas
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA