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Background & Aims: Exploiting key regulators responsible for hepatocarcinogenesis is of great importance for the prevention and treatment of hepatocellular carcinoma (HCC). However, the key players contributing to hepatocarcinogenesis remain poorly understood. We explored the molecular mechanisms underlying the carcinogenesis and progression of HCC for the development of potential new therapeutic targets. Methods: The Cancer Genome Atlas-Liver Hepatocellular Carcinoma (TCGA-LIHC) and Genotype-Tissue Expression (GTEx) databases were used to identify genes with enhanced expression in the liver associated with HCC progression. A murine liver-specific Ftcd knockout (Ftcd-LKO) model was generated to investigate the role of formimidoyltransferase cyclodeaminase (FTCD) in HCC. Multi-omics analysis of transcriptomics, metabolomics, and proteomics data were applied to further analyse the molecular effects of FTCD expression on hepatocarcinogenesis. Functional and biochemical studies were performed to determine the significance of loss of FTCD expression and the therapeutic potential of Akt inhibitors in FTCD-deficient cancer cells. Results: FTCD is highly expressed in the liver but significantly downregulated in HCC. Patients with HCC and low levels of FTCD exhibited worse prognosis, and patients with liver cirrhosis and low FTCD levels exhibited a notable higher probability of developing HCC. Hepatocyte-specific knockout of FTCD promoted both chronic diethylnitrosamine-induced and spontaneous hepatocarcinogenesis in mice. Multi-omics analysis showed that loss of FTCD affected fatty acid and cholesterol metabolism in hepatocarcinogenesis. Mechanistically, loss of FTCD upregulated peroxisome proliferator-activated receptor (PPAR)γ and sterol regulatory element-binding protein 2 (SREBP2) by regulating the PTEN/Akt/mTOR signalling axis, leading to lipid accumulation and hepatocarcinogenesis. Conclusions: Taken together, we identified a FTCD-regulated lipid metabolic mechanism involving PPARγ and SREBP2 signaling in hepatocarcinogenesis and provide a rationale for therapeutically targeting of HCC driven by downregulation of FTCD. Impact and implications: Exploiting key molecules responsible for hepatocarcinogenesis is significant for the prevention and treatment of HCC. Herein, we identified formimidoyltransferase cyclodeaminase (FTCD) as the top enhanced gene, which could serve as a predictive and prognostic marker for patients with HCC. We generated and characterised the first Ftcd liver-specific knockout murine model. We found loss of FTCD expression upregulated peroxisome proliferator-activated receptor (PPAR)γ and sterol regulatory element-binding protein 2 (SREBP2) by regulating the PTEN/Akt/mTOR signalling axis, leading to lipid accumulation and hepatocarcinogenesis, and provided a rationale for therapeutic targeting of HCC driven by downregulation of FTCD.
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PURPOSE: Although immunotherapy improves clinical outcomes in several types of malignancies, as an immunologically 'cold' tumor, pancreatic ductal adenocarcinoma (PDAC) is arrantly resistant to immunotherapy. However, the role of N6-methyladenosine (m6A) modification in the immune microenvironment of PDAC is still poorly understood. METHODS: The Cancer Genome Atlas (TCGA) and Gene Expression Omnibus (GEO) datasets were used to identify differentially expressed m6A related enzymes. The biological role and mechanism of METTL3 in PDAC growth and metastasis were determined in vitro and in vivo. RNA-sequencing and bioinformatics analysis were used to identify signaling pathways involved in METTL3. Western blot, m6A dot blot assays, co-immunoprecipitation, immunofluorescence, and flow cytometry were used to explore the molecular mechanism. RESULTS: Here, we demonstrate that METTL3, the key regulator of m6A modification, is downregulated in PDAC, and negatively correlates with PDAC malignant features. Elevated METTL3 suppresses PDAC growth and overcomes resistance to immune checkpoint blockade. Mechanistically, METTL3 promotes the accumulation of endogenous double-stranded RNA (dsRNA) through protecting m6A-transcripts from further Adenosine-to-inosine (A-to-I) editing. The dsRNA stress activates RIG-I-like receptors (RLRs) to enhance anti-tumor immunity, finally suppressing PDAC progression. CONCLUSION: Our findings indicate that tumor cell-intrinsic m6A modification participates in the regulation of tumor immune landscape. Adjusting the m6A level may be an effective strategy to overcome the resistance to immunotherapy and increase responsiveness to immunotherapy in PDAC.
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Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Humanos , RNA de Cadeia Dupla , Neoplasias Pancreáticas/genética , Carcinoma Ductal Pancreático/genética , Adenosina , Microambiente Tumoral , Metiltransferases , Neoplasias PancreáticasRESUMO
Musculoskeletal diseases, such as osteoporosis and sarcopenia, are tremendous and growing public health concerns. Considering the intimate functional relationship between muscle and bone throughout development, growth, and aging, muscle provides the primary source of skeletal loading through contraction force. However, significant gaps exist in our knowledge regarding the role of muscle in bone homeostasis and little is known regarding the mechanism through which the central nervous system responds and regulates unloading-induced bone loss. Here, we showed that the basolateral amygdala (BLA) and medial part of the central nucleus (CeM) are anatomically connected with the musculoskeletal system. Unloading-induced bone loss is accompanied by a decrease in serum semaphorin 3A (Sema3A) levels as well as sensory denervation. In vivo fiber photometry recordings indicated that the mechanical signal is integrated by the BLA and CeM within 24 h and subsequently regulates bone remodeling. Moreover, chemogenetic activation of BLA CaMKII neurons mitigates severe bone loss caused by mechanical unloading via increased serum levels of Sema3A and sensory innervation. These results indicate that the BLA integrates the mechanosensory signals rapidly and mediates the systemic hormonal secretion of Sema3A to maintain bone homeostasis.
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Circular RNAs (circRNA) are a class of covalently closed single-stranded RNAs that have been implicated in cancer progression. Here we identify circNDUFB2 to be downregulated in non-small cell lung cancer (NSCLC) tissues, and to negatively correlate with NSCLC malignant features. Elevated circNDUFB2 inhibits growth and metastasis of NSCLC cells. Mechanistically, circNDUFB2 functions as a scaffold to enhance the interaction between TRIM25 and IGF2BPs, a positive regulator of tumor progression and metastasis. This TRIM25/circNDUFB2/IGF2BPs ternary complex facilitates ubiquitination and degradation of IGF2BPs, with this effect enhanced by N6-methyladenosine (m6A) modification of circNDUFB2. Moreover, circNDUFB2 is also recognized by RIG-I to activate RIG-I-MAVS signaling cascades and recruit immune cells into the tumor microenvironment (TME). Our data thus provide evidences that circNDUFB2 participates in the degradation of IGF2BPs and activation of anti-tumor immunity during NSCLC progression via the modulation of both protein ubiquitination and degradation, as well as cellular immune responses.
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Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/imunologia , Progressão da Doença , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/imunologia , RNA Circular/metabolismo , Proteínas de Ligação a RNA/metabolismo , Animais , Carcinoma Pulmonar de Células não Pequenas/patologia , Proliferação de Células , Proteína DEAD-box 58/metabolismo , Regulação para Baixo/genética , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Neoplasias Pulmonares/patologia , Camundongos Endogâmicos BALB C , Camundongos Nus , Modelos Biológicos , Metástase Neoplásica , Complexo de Endopeptidases do Proteassoma/metabolismo , Ligação Proteica , Estabilidade Proteica , Proteólise , RNA Circular/genética , RNA Mensageiro/genética , RNA Mensageiro/metabolismo , Receptores Imunológicos , Fatores de Transcrição/metabolismo , Proteínas com Motivo Tripartido/metabolismo , Ubiquitina/metabolismo , Ubiquitina-Proteína Ligases/metabolismo , UbiquitinaçãoRESUMO
BACKGROUND AND AIMS: Peroxisome proliferator-activated receptor-gamma (PPARγ) coactivator-1α (PGC1α) is a key regulator of mitochondrial biogenesis and respiration. PGC1α is involved in the carcinogenesis, progression, and metabolic state of cancer. However, its role in the progression of hepatocellular carcinoma (HCC) remains unclear. APPROACH AND RESULTS: In this study, we observed that PGC1α was down-regulated in human HCC. A clinical study showed that low levels of PGC1α expression were correlated with poor survival, vascular invasion, and larger tumor size. PGC1α inhibited the migration and invasion of HCC cells with both in vitro experiments and in vivo mouse models. Mechanistically, PGC1α suppressed the Warburg effect through down-regulation of pyruvate dehydrogenase kinase isozyme 1 (PDK1) mediated by the WNT/ß-catenin pathway, and inhibition of the WNT/ß-catenin pathway was induced by activation of PPARγ. CONCLUSIONS: Low levels of PGC1α expression indicate a poor prognosis for HCC patients. PGC1α suppresses HCC metastasis by inhibiting aerobic glycolysis through regulating the WNT/ß-catenin/PDK1 axis, which depends on PPARγ. PGC1α is a potential factor for predicting prognosis and a therapeutic target for HCC patients.
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Biomarcadores Tumorais/metabolismo , Carcinoma Hepatocelular/secundário , Neoplasias Hepáticas/patologia , Neoplasias Pulmonares/secundário , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/metabolismo , Biomarcadores Tumorais/sangue , Carcinogênese/genética , Carcinogênese/patologia , Carcinoma Hepatocelular/sangue , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/mortalidade , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Progressão da Doença , Feminino , Regulação Neoplásica da Expressão Gênica , Humanos , Fígado/patologia , Fígado/cirurgia , Neoplasias Hepáticas/sangue , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/mortalidade , Masculino , Pessoa de Meia-Idade , Invasividade Neoplásica/genética , Invasividade Neoplásica/patologia , PPAR gama/metabolismo , Coativador 1-alfa do Receptor gama Ativado por Proliferador de Peroxissomo/sangue , Prognóstico , Piruvato Desidrogenase Quinase de Transferência de Acetil/metabolismo , Efeito Warburg em Oncologia , Via de Sinalização Wnt/genética , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
BACKGROUND: Biological role and clinical significance of circular RNAs (circRNAs) remain largely unknown. Herein, we aimed to investigate biological function, molecular mechanism, and clinical significance of a circular RNA FOXM1 (circFOXM1) in non-small cell lung cancer (NSCLC). METHODS: Expression of circFOXM1 was measured in 48 paired samples of NSCLC by qRT-PCR. Functional roles of circFOXM1 on tumor cells were explored by in vitro and in vivo assays. Transcriptome sequencing was employed to screen the molecules involved in circFOXM1 regulatory network. RNA immunoprecipitation, luciferase analysis, RNA pull-down, and rescue assay were used to investigate potential mechanisms of circFOXM1. RESULTS: We found that circFOXM1 was significantly upregulated in NSCLC tissues, and its upregulation was positively correlated with advanced clinical stage and poor prognosis of NSCLC patients. Gain or loss-of-function assay showed that circFOXM1 promoted cell proliferation and cell cycle progression. In vivo assays showed that silencing circFOXM1 inhibited xenograft tumor growth. Mechanically, transcriptome sequencing data indicated that silencing circFOXM1 led to the downregulation of cell cycle-related mRNAs. RNA pull-down and dual-luciferase reporter assay suggested that circFOXM1 could bind to miR-614, and FAM83D was an essential gene involved in the circFOXM1/miR-614 regulatory network. CONCLUSIONS: circFOXM1promotes NSCLC progression by interacting with miR-614 and thus inactivating the function of miR-614, which will further release the suppression of FAM83D. circFOXM1/miR-614/FAM83D regulatory network may serve as a potential therapeutic target for NSCLC patients.
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Carcinoma Pulmonar de Células não Pequenas/metabolismo , Proteínas de Ciclo Celular/metabolismo , Proteína Forkhead Box M1/genética , Neoplasias Pulmonares/metabolismo , Proteínas Associadas aos Microtúbulos/metabolismo , RNA Circular/metabolismo , Carcinoma Pulmonar de Células não Pequenas/genética , Carcinoma Pulmonar de Células não Pequenas/patologia , Proteínas de Ciclo Celular/genética , Linhagem Celular Tumoral , Proliferação de Células/fisiologia , Feminino , Proteína Forkhead Box M1/metabolismo , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , Masculino , Proteínas Associadas aos Microtúbulos/genética , Pessoa de Meia-Idade , RNA Circular/genética , Regulação para CimaRESUMO
Circular RNAs (circRNAs) are identified as vital regulators in a variety of cancers. However, the role of circRNA in lung squamous cell carcinoma (LUSC) remains largely unknown. Herein, we explore the expression profiles of circRNA and mRNA in 5 paired samples of LUSC. By analyzing the co-expression network of differentially expressed circRNAs and dysregulated mRNAs, we identify that a cell cycle-related circRNA, circTP63, is upregulated in LUSC tissues and its upregulation is correlated with larger tumor size and higher TNM stage in LUSC patients. Elevated circTP63 promotes cell proliferation both in vitro and in vivo. Mechanistically, circTP63 shares miRNA response elements with FOXM1. circTP63 competitively binds to miR-873-3p and prevents miR-873-3p to decrease the level of FOXM1, which upregulates CENPA and CENPB, and finally facilitates cell cycle progression.
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Carcinoma de Células Escamosas/metabolismo , Progressão da Doença , Proteína Forkhead Box M1/metabolismo , Regulação Neoplásica da Expressão Gênica , RNA Circular/metabolismo , Fatores de Transcrição/metabolismo , Proteínas Supressoras de Tumor/metabolismo , Regulação para Cima , Animais , Carcinoma de Células Escamosas/genética , Ciclo Celular/fisiologia , Linhagem Celular Tumoral , Proliferação de Células , Proteína Centromérica A/metabolismo , Proteína B de Centrômero/metabolismo , Feminino , Perfilação da Expressão Gênica , Redes Reguladoras de Genes , Estudos de Associação Genética , Predisposição Genética para Doença , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/metabolismo , Masculino , Camundongos Endogâmicos BALB C , MicroRNAs , Pessoa de Meia-Idade , Neoplasias Experimentais , RNA Circular/genética , RNA Mensageiro/metabolismo , Fatores de Transcrição/genética , Transcriptoma , Proteínas Supressoras de Tumor/genéticaRESUMO
Alterations in cellular metabolism are one of the characteristics in cancer. They are not only the result of tumor progression but also the cause of cancer initiation. Pyruvate dehydrogenase kinase 4 (PDK4) is a key metabolic enzyme, which regulates cell metabolism by inhibiting pyruvate dehydrogenase (PDH). However, the function and regulating mechanism of PDK4 in HCC remain unclear. Here, we found that the expression of PDK4 was significantly decreased in HCC tissues, and its downregulation could predict poor prognosis of HCC patients. Silencing PDK4 significantly facilitated proliferation and migration of HCC cells. Knockdown of PDK4 didn't influence the oxidative phosphorylation and glycolysis capacity of HCC cells in vitro. However, knockdown of PDK4 increased expression of key lipogenic enzymes, fatty acid synthase (FASN) and stearoyl-CoA desaturase (SCD), which finally induced lipogenesis. These data suggest that PDK4 inhibits proliferation and migration of HCC cells probably via suppressing lipogenesis.
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Long noncoding RNAs (lncRNAs) have been associated with hepatocellular carcinoma (HCC), but the underlying molecular mechanisms of their specific association with hepatocarcinogenesis have not been fully explored. Methods: miR503HG was identified by microarray and validated by real-time PCR. Survival analysis was evaluated using the Kaplan-Meier method and assessed using the log-rank test. In vitro and in vivo assays were preformed to explore the biological effects of miR503HG in HCC cells. The interaction of miR503HG with HNRNPA2B1 was identified by RNA pull-down and RNA immunoprecipitation. Expression of HNRNPA2B1 was examined by western blotting, immunofluorescence and immunohistochemical analyses, while HNRNPA2B1 ubiquitination was detected by immunoprecipitation. Results: We have identified 713 differentially expressed lncRNAs in 12 pairs of HCC tissues compared with corresponding noncancerous liver tissues. One of these lncRNAs, miR503HG, the host gene of miR503, is markedly decreased in HCC. Expression level of miR503HG is significantly associated with the time to recurrence and overall survival and is an independent risk factor for recurrence and survival. Enhanced expression of miR503HG could noticeably inhibit HCC invasion and metastasis in vitro and in vivo. Further investigation suggested that miR503HG could specifically interact with the heterogeneous nuclear ribonucleoprotein A2/B1 (HNRNPA2B1). miR503HG promoted HNRNPA2B1 degradation via the ubiquitin-proteasome pathway, which reduced the stability of p52 and p65 mRNA, and simultaneously suppressed the NF-κB signaling pathway in HCC cells. In addition, miR503HG can function synergistically with miR503 to inhibit HCC migration. Conclusion: Our findings support a role for miR503HG in tumor recurrence risk and survival prediction in HCC patients. We demonstrate a novel mechanism by which miR503HG inhibits the NF-κB signaling pathway and exerts its metastatic tumor suppression function through modulating the ubiquitination status of HNRNPA2B1.
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Biomarcadores Tumorais/genética , Carcinoma Hepatocelular/metabolismo , Ribonucleoproteínas Nucleares Heterogêneas Grupo A-B/metabolismo , Neoplasias Hepáticas/metabolismo , RNA Longo não Codificante/genética , Biomarcadores Tumorais/metabolismo , Carcinoma Hepatocelular/genética , Linhagem Celular Tumoral , Feminino , Células HEK293 , Humanos , Neoplasias Hepáticas/genética , Masculino , Pessoa de Meia-Idade , NF-kappa B/metabolismo , Metástase Neoplásica , RNA Longo não Codificante/metabolismo , Transdução de Sinais , UbiquitinaçãoRESUMO
Tet methylcytosine dioxygenases (TETs) catalyze the oxidative reactions of 5-methylcytosine to 5-hydroxymethylcytosine (5hmC). However, TET1 roles in ovarian cancer cell growth are unknown. Here, we show that ectopic expression of TET1 increased 5hmC levels, and inhibited proliferation and colony formation in ovarian cancer cell lines. Furthermore, in vitro and in vivo functional studies demonstrated that TET1 overexpression is necessary for the suppression of ovarian cancer growth, whereas depletion of TET1 expression had the opposite effect. Furthermore, the results of RNA-seq and qRT-PCR analyses identified a tumor suppressor, Ras association domain family member 5 (RASSF5), as the key downstream target of TET1. TET1 promotes RASSF5 expression by demethylating a CpG site within RASSF5 promoter. Up-regulated RASSF5 expression leads to the suppression of ovarian cancer cells growth. Additionally, we demonstrated that inhibition of CUL4-DDB1 ubiquitin ligase complex decrease 5hmC levels in ovarian cancer cells. These results provide new insights into the understanding of how ovarian cancers develop and grow, and identify TET1 as a key player in this process.
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STUDY QUESTION: What is the physiological function of Yes-associated protein-1 (Yap1), a susceptibility gene for polycystic ovary syndrome (PCOS), in ovarian granulosa cells (GCs)? SUMMARY ANSWER: Physiologically, steroid sex hormones stimulate follicle growth by activating YAP1; however, the preovulatory inhibition of YAP1 activity in GCs is a prerequisite of LH actions. WHAT IS KNOWN ALREADY: PCOS is a common gynecologic and endocrine disease with multiple short and long-term consequences. Many PCOS patients suffer anovulation caused by hyperandrogenism, but its etiology remains unclear. STUDY DESIGN, SIZE, DURATION: To study the effect of acute hyperandrogenism on ovulation, we injected pregnant mare serum gonadotrophin (PMSG)-primed (44 h) pubertal mice with dihydrotestosterone (DHT), the major biologically active form of androgen, in a superovulation assay. We investigated if YAP1 is regulated by testosterone and if it is potentially involved in follicle development and ovulation. Cultured primary GCs were subjected to Yap1 depletion by RNA interference and Yap1 overexpression by adenoviral infections. PARTICIPANTS/MATERIALS, SETTING, METHODS: Female mice at postnatal day (PD)-21~23 were analyzed to avoid the complexity of ovarian functions associated with estrous cycles and endogenous surges of gonadotropins. Immature mice were injected intraperitoneally with five IU PMSG to stimulate preovulatory follicle development followed 44 h later with five IU hCG to stimulate ovulation. For DHT treatments, female mice at PD23 were injected intraperitoneally with five IU PMSG followed 44 h later with five IU hCG alone (as control) or five IU hCG plus 100 µg DHT, which was dissolved in 0.1 ml DMSO. Methods of gene expression detection used include immunohistochemistry, immunofluorescence, Western blotting and quantitative PCR. More than three biological and technical replicates were included in each experiments. MAIN RESULTS AND THE ROLE OF CHANCE: we provide novel evidence in a mouse model that YAP1 is required for proliferation of ovarian GCs, but is down-regulated by LH through the extracellular-regulated kinase-1/2 (ERK1/2) cascade. Acute hyperandrogenism blocks LH actions and causes oligo-ovulation by activating YAP1. LARGE SCALE DATA: N/A. LIMITATIONS, REASONS FOR CAUTION: Results shown were obtained only in mouse, and need to be further confirmed in human samples. WIDER IMPLICATIONS OF THE FINDINGS: These findings not only elucidated the role of YAP1 in maintaining normal ovarian functions, but also link the YAP1 deregulation to the pathogenesis of PCOS. STUDY FUNDING AND COMPETING INTEREST(S): This study is funded by the National Key Research and Development Program of China (2016YFC1000600 and 2017YFSF1001500) and National Natural Science Foundation of China (31528016, 31371449 and 31671558). The authors have no competing interests.
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Proteínas Adaptadoras de Transdução de Sinal/genética , Gonadotropina Coriônica/farmacologia , Di-Hidrotestosterona/farmacologia , Células da Granulosa/efeitos dos fármacos , Hiperandrogenismo/genética , Fosfoproteínas/genética , Síndrome do Ovário Policístico/genética , Proteínas Adaptadoras de Transdução de Sinal/metabolismo , Animais , Proteínas de Ciclo Celular , Proliferação de Células/efeitos dos fármacos , Modelos Animais de Doenças , Feminino , Regulação da Expressão Gênica , Gonadotropinas Equinas/farmacologia , Células da Granulosa/citologia , Células da Granulosa/metabolismo , Cavalos , Humanos , Hiperandrogenismo/metabolismo , Hiperandrogenismo/patologia , Hormônio Luteinizante/genética , Hormônio Luteinizante/metabolismo , Camundongos , Proteína Quinase 1 Ativada por Mitógeno/genética , Proteína Quinase 1 Ativada por Mitógeno/metabolismo , Proteína Quinase 3 Ativada por Mitógeno/genética , Proteína Quinase 3 Ativada por Mitógeno/metabolismo , Ovário/citologia , Ovário/efeitos dos fármacos , Ovário/metabolismo , Ovulação/efeitos dos fármacos , Fosfoproteínas/metabolismo , Síndrome do Ovário Policístico/induzido quimicamente , Síndrome do Ovário Policístico/metabolismo , Síndrome do Ovário Policístico/patologia , Cultura Primária de Células , Transdução de Sinais , Proteínas de Sinalização YAPRESUMO
Trimethylation of histone H3 at lysine-4 (H3K4me3) is associated with eukaryotic gene promoters and poises their transcriptional activation during development. To examine the in vivo function of H3K4me3 in the absence of DNA replication, we deleted CXXC finger protein 1 (CFP1), the DNA-binding subunit of the SETD1 histone H3K4 methyltransferase, in developing oocytes. We find that CFP1 is required for H3K4me3 accumulation and the deposition of histone variants onto chromatin during oocyte maturation. Decreased H3K4me3 in oocytes caused global downregulation of transcription activity. Oocytes lacking CFP1 failed to complete maturation and were unable to gain developmental competence after fertilization, due to defects in cytoplasmic lattice formation, meiotic division, and maternal-zygotic transition. Our study highlights the importance of H3K4me3 in continuous histone replacement for transcriptional regulation, chromatin remodeling, and normal developmental progression in a non-replicative system.
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Montagem e Desmontagem da Cromatina , Cromatina/metabolismo , Histonas/metabolismo , Oócitos/metabolismo , Transativadores/metabolismo , Animais , Cromatina/genética , Feminino , Deleção de Genes , Histonas/genética , Metilação , Camundongos , Camundongos Transgênicos , Oócitos/citologia , Transativadores/genéticaRESUMO
Mitochondrial dynamics change mitochondrial morphological features and numbers as a part of adaptive cellular metabolism, which is vital for most eukaryotic cells and organisms. A disease or even death of an animal can occur if these dynamics are disrupted. Using large-scale genetic screening in fruit flies, we previously found the gene mitoguardin (Miga), which encodes a mitochondrial outer-membrane protein and promotes mitochondrial fusion. Knockout mouse strains were generated for the mammalian Miga homologs Miga1 and Miga2. Miga1/2-/- females show greatly reduced quality of oocytes and early embryos and are subfertile. Mitochondria became clustered in the cytoplasm of oocytes from the germinal-vesicle stage to meiosis II; production of reactive oxygen species increased in mitochondria and caused damage to mitochondrial ultrastructures. Additionally, reduced ATP production, a decreased mitochondrial-DNA copy number, and lower mitochondrial membrane potential were detected in Miga1/2-/- oocytes during meiotic maturation. These changes resulted in low rates of polar-body extrusion during oocyte maturation, reduced developmental potential of the resulting early embryos, and consequently female subfertility. We provide direct evidence that MIGA1/2-regulated mitochondrial dynamics is crucial for mitochondrial functions, ensure oocyte maturation, and maintain the developmental potential.