RESUMO
Glioblastomas (GBMs) are the most lethal primary brain tumors with limited survival, even under aggressive treatments. The current therapeutics for GBMs are flawed due to the failure to accurately discriminate between normal proliferating cells and distinctive tumor cells. Mitochondria are essential to GBMs and serve as potential therapeutical targets. Here, we utilize cryo-electron tomography to quantitatively investigate nanoscale details of randomly sampled mitochondria in their native cellular context of GBM cells. Our results show that compared with cancer-free brain cells, GBM cells own more inter-mitochondrial junctions of several types for communications. Furthermore, our tomograms unveil microtubule-dependent mitochondrial nanotunnel-like bridges in the GBM cells as another inter-mitochondrial structure. These quantified inter-mitochondrial features, together with other mitochondria-organelle and intra-mitochondrial ones, are sufficient to distinguish GBM cells from cancer-free brain cells under scrutiny with predictive modeling. Our findings decipher high-resolution inter-mitochondrial structural signatures and provide clues for diagnosis and therapeutic interventions for GBM and other mitochondria-related diseases.
Assuntos
Neoplasias Encefálicas , Glioblastoma , Humanos , Glioblastoma/patologia , Neoplasias Encefálicas/patologia , Tomografia com Microscopia Eletrônica , Encéfalo/patologia , Mitocôndrias/patologiaRESUMO
The endosomal sorting complexes required for transport (ESCRTs) are responsible for membrane remodeling in many cellular processes, such as multivesicular body biogenesis, viral budding, and cytokinetic abscission. ESCRT-III, the most abundant ESCRT subunit, assembles into flat spirals as the primed state, essential to initiate membrane invagination. However, the three-dimensional architecture of ESCRT-III flat spirals remained vague for decades due to highly curved filaments with a small diameter and a single preferred orientation on the membrane. Here, we unveiled that yeast Snf7, a component of ESCRT-III, forms flat spirals on the lipid monolayers using cryogenic electron microscopy. We developed a geometry-constrained Euler angle-assigned reconstruction strategy and obtained moderate-resolution structures of Snf7 flat spirals with varying curvatures. Our analyses showed that Snf7 subunits recline on the membrane with N-terminal motifs α0 as anchors, adopt an open state with fused α2/3 helices, and bend α2/3 gradually from the outer to inner parts of flat spirals. In all, we provide the orientation and conformations of ESCRT-III flat spirals on the membrane and unveil the underlying assembly mechanism, which will serve as the initial step in understanding how ESCRTs drive membrane abscission.
Assuntos
Microscopia Crioeletrônica , Complexos Endossomais de Distribuição Requeridos para Transporte , Proteínas de Saccharomyces cerevisiae , Membrana Celular/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/metabolismo , Complexos Endossomais de Distribuição Requeridos para Transporte/química , Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/metabolismo , Proteínas de Saccharomyces cerevisiae/química , Proteínas de Saccharomyces cerevisiae/ultraestruturaRESUMO
Researchers commonly anneal metals, alloys, and semiconductors to repair defects and improve microstructures via recrystallization. Theoretical studies indicate that simulated annealing on biological macromolecules helps predict the final structures with minimum free energy. Experimental validation of this homogenizing effect and further exploration of its applications are fascinating scientific questions that remain elusive. Here, we chose the apo-state 70S ribosome from Escherichia coli as a model, wherein the 30S subunit undergoes a thermally driven intersubunit rotation and exhibits substantial structural flexibility as well as distinct free energy. We experimentally demonstrate that annealing at a fast cooling rate enhances the 70S ribosome homogeneity and improves local resolution on the 30S subunit. After annealing, the 70S ribosome is in a nonrotated state with respect to corresponding intermediate structures in unannealed or heated ribosomes. Manifold-based analysis further indicates that the annealed 70S ribosome takes a narrow conformational distribution and exhibits a minimum-energy state in the free-energy landscape. Our experimental results offer a facile yet robust approach to enhance protein stability, which is ideal for high-resolution cryogenic electron microscopy. Beyond structure determination, annealing shows great potential for synchronizing proteins on a single-molecule level and can be extended to study protein folding and explore conformational and energy landscapes.
Assuntos
Conformação Proteica , Proteínas Ribossômicas/ultraestrutura , Ribossomos/fisiologia , Microscopia Crioeletrônica , Escherichia coli/metabolismo , Proteínas de Escherichia coli/metabolismo , Modelos Moleculares , RNA Ribossômico/metabolismo , RNA Ribossômico/ultraestrutura , Proteínas Ribossômicas/metabolismo , Ribossomos/ultraestruturaRESUMO
BACKGROUND: Ancient northern East Asians (ANEA) from the Yellow River region, who pioneered millet cultivation, play a crucial role in understanding the origins of ethnolinguistically diverse populations in modern China and the entire landscape of deep genetic structure and variation discovery in modern East Asians. However, the direct links between ANEA and geographically proximate modern populations, as well as the biological adaptive processes involved, remain poorly understood. RESULTS: Here, we generated genome-wide SNP data for 264 individuals from geographically different Han populations in Shandong. An integrated genomic resource encompassing both modern and ancient East Asians was compiled to examine fine-scale population admixture scenarios and adaptive traits. The reconstruction of demographic history and hierarchical clustering patterns revealed that individuals from the Shandong Peninsula share a close genetic affinity with ANEA, indicating long-term genetic continuity and mobility in the lower Yellow River basin since the early Neolithic period. Biological adaptive signatures, including those related to immune and metabolic pathways, were identified through analyses of haplotype homozygosity and allele frequency spectra. These signatures are linked to complex traits such as height and body mass index, which may be associated with adaptations to cold environments, dietary practices, and pathogen exposure. Additionally, allele frequency trajectories over time and a haplotype network of two highly differentiated genes, ABCC11 and SLC10A1, were delineated. These genes, which are associated with axillary odor and bilirubin metabolism, respectively, illustrate how local adaptations can influence the diversification of traits in East Asians. CONCLUSIONS: Our findings provide a comprehensive genomic dataset that elucidates the fine-scale genetic history and evolutionary trajectory of natural selection signals and disease susceptibility in Han Chinese populations. This study serves as a paradigm for integrating spatiotemporally diverse ancient genomes in the era of population genomic medicine.
Assuntos
Genética Populacional , Haplótipos , Polimorfismo de Nucleotídeo Único , Humanos , China , Genômica , Evolução Molecular , Frequência do Gene , Povo Asiático/genética , Genoma HumanoRESUMO
BACKGROUND: Establishing whether there is a potential relationship between glucagon-like peptide 1 receptor agonists (GLP-1RAs) and suicidal or self-injurious behaviors (SSIBs) is crucial for public safety. This study investigated the potential association between GLP-1RAs and SSIBs by exploring the FDA Adverse Event Reporting System (FAERS) database. METHODS: A disproportionality analysis was conducted using post-marketing data from the FAERS repository (2018 Q1 to 2022 Q4). SSIB cases associated with GLP-1RAs were identified and analyzed through disproportionality analysis using the information component. The parametric distribution with a goodness-of-fit test was employed to analyze the time-to-onset, and the Ω shrinkage was used to evaluate the potential effect of co-medication on the occurrence of SSIBs. RESULTS: In total, 204 cases of SSIBs associated with GLP-1RAs, including semaglutide, liraglutide, dulaglutide, exenatide, and albiglutide, were identified in the FAERS database. Time-of-onset analysis revealed no consistent mechanism for the latency of SSIBs in patients receiving GLP-1RAs. The disproportionality analysis did not indicate an association between GLP-1RAs and SSIBs. Co-medication analysis revealed 81 cases with antidepressants, antipsychotics, and benzodiazepines, which may be proxies of mental health comorbidities. CONCLUSIONS: We found no signal of disproportionate reporting of an association between GLP-1RA use and SSIBs. Clinicians need to maintain heightened vigilance on patients premedicated with neuropsychotropic drugs. This contributes to the greater acceptance of GLP-1RAs in patients with type 2 diabetes mellitus or obesity.
Assuntos
Diabetes Mellitus Tipo 2 , Humanos , Diabetes Mellitus Tipo 2/complicações , Hipoglicemiantes/uso terapêutico , Agonistas do Receptor do Peptídeo 1 Semelhante ao Glucagon , Farmacovigilância , Ideação SuicidaRESUMO
BACKGROUND: Previous studies have demonstrated that natural killer (NK) cells migrated into the liver from peripheral organs and exerted cytotoxic effects on hepatocytes in virus-induced liver failure. AIM: This study aimed to investigate the potential therapeutic role of chemokine receptors in the migration of NK cells in a murine hepatitis virus strain 3 (MHV-3)-induced fulminant hepatic failure (MHV-3-FHF) model and its mechanism. RESULTS: By gene array analysis, chemokine (C-C motif) receptor 5 (CCR5) was found to have remarkably elevated expression levels in hepatic NK cells after MHV-3 infection. The number of hepatic CCR5+ conventional NK (cNK) cells increased and peaked at 48 h after MHV-3 infection, while the number of hepatic resident NK (rNK) cells steadily declined. Moreover, the expression of CCR5-related chemokines, including macrophage inflammatory protein (MIP)-1α, MIP-1ß and regulated on activation, normal T-cell expressed and secreted (RANTES) was significantly upregulated in MHV-3-infected hepatocytes. In an in vitro Transwell migration assay, CCR5-blocked splenic cNK cells showed decreased migration towards MHV-3-infected hepatocytes, and inhibition of MIP-1ß or RANTES but not MIP-1α decreased cNK cell migration. Moreover, CCR5 knockout (KO) mice displayed reduced infiltration of hepatic cNK cells after MHV-3 infection, accompanied by attenuated liver injury and improved mouse survival time. Adoptive transfer of cNK cells from wild-type mice into CCR5 KO mice resulted in the abundant accumulation of hepatic cNK cells and aggravated liver injury. Moreover, pharmacological inhibition of CCR5 by maraviroc reduced cNK cell infiltration in the liver and liver injury in the MHV-3-FHF model. CONCLUSION: The CCR5-MIP-1ß/RANTES axis played a critical role in the recruitment of cNK cells to the liver during MHV-3-induced liver injury. Targeted inhibition of CCR5 provides a therapeutic approach to ameliorate liver damage during virus-induced acute liver injury.
Assuntos
Falência Hepática Aguda , Vírus da Hepatite Murina , Animais , Camundongos , Quimiocina CCL3 , Quimiocina CCL4 , Quimiocina CCL5 , Quimiocinas , Quimiocinas CC , Células Matadoras Naturais , Receptores CCR5 , Receptores de QuimiocinasRESUMO
The central nervous system has evolved to coordinate the regulation of both the behavior response to the external environment and homeostasis of energy expenditure. Recent studies have indicated the dorsomedial ventromedial hypothalamus (dmVMH) as an important hub that regulates both innate behavior and energy homeostasis for coping stress. However, how dmVMH neurons control neuronal firing pattern to regulate chronic stress-induced anxiety and energy expenditure remains poorly understood. Here, we found enhanced neuronal activity in VMH after chronic stress, which is mainly induced by increased proportion of burst firing neurons. This enhancement of VMH burst firing is predominantly mediated by Cav3.1 expression. Optogenetically evoked burst firing of dmVMH neurons induced anxiety-like behavior, shifted the respiratory exchange ratio toward fat oxidation, and decreased food intake, while knockdown of Cav3.1 in the dmVMH had the opposite effects, suggested that Cav 3.1 as a crucial regulator. Interestingly, we found that fluoxetine (anxiolytics) could block the increase of Cav3.1 expression to inhibit the burst firing, and then rescued the anxiety-like behaviors and energy expenditure changes. Collectively, our study first revealed an important role of Cav3.1-driven bursting firing of dmVMH neurons in the control of anxiety-like behavior and energy expenditure, and provided potential therapeutic targets for treating the chronic stress-induced emotional malfunction and metabolism disorders.
Assuntos
Hipotálamo , Neurônios , Ansiedade , Metabolismo Energético , Neurônios/metabolismoRESUMO
Glioblastoma (GBM) is a primary tumor in the intracranial compartment. Vasculogenic mimicry (VM) is a process in which a pipeline of tumor cells that provide blood support to carcinogenic cells is formed, and studying VM could provide a new strategy for clinical targeted treatment of GBM. In the present study, we found that SNORD17 and ZNF384 were significantly upregulated and promoted VM in GBM, whereas KAT6B was downregulated and inhibited VM in GBM. RTL-P assays were performed to verify the 2'-O-methylation of KAT6B by SNORD17; IP assays were used to detect the acetylation of ZNF384 by KAT6B. In addition, the binding of ZNF384 to the promoter regions of VEGFR2 and VE-cadherin promoted transcription, as validated by chromatin immunoprecipitation and luciferase reporter assays. And finally, knockdown of SNORD17 and ZNF384 combined with KAT6B overexpression effectively reduced the xenograft tumor size, prolonged the survival time of nude mice and reduced the number of VM channels. This study reveals a novel mechanism of the SNORD17/KAT6B/ZNF384 axis in modulating VM development in GBM that may provide a new goal for the comprehensive treatment of GBM.
Assuntos
Glioblastoma , Animais , Camundongos , Humanos , Glioblastoma/genética , Glioblastoma/tratamento farmacológico , Camundongos Nus , Metilação , Linhagem Celular Tumoral , RNA Mensageiro , Histona Acetiltransferases/uso terapêuticoRESUMO
Human malignant gliomas are the most common and aggressive primary malignant tumors of the human central nervous system. Vasculogenic mimicry (VM), which refers to the formation of a tumor blood supply system independently of endothelial cells, contributes to the malignant progression of glioma. Therefore, VM is considered a potential target for glioma therapy. Accumulated evidence indicates that alterations in SUMOylation, a reversible post-translational modification, are involved in tumorigenesis and progression. In the present study, we found that UBA2 and RALY were upregulated in glioma tissues and cell lines. Downregulation of UBA2 and RALY inhibited the migration, invasion, and VM of glioma cells. RALY can be SUMOylated by conjugation with SUMO1, which is facilitated by the overexpression of UBA2. The SUMOylation of RALY increases its stability, which in turn increases its expression as well as its promoting effect on FOXD1 mRNA. The overexpression of FOXD1 promotes DKK1 transcription by activating its promoter, thereby promoting glioma cell migration, invasion, and VM. Remarkably, the combined knockdown of UBA2, RALY, and FOXD1 resulted in the smallest tumor volumes and the longest survivals of nude mice in vivo. UBA2/RALY/FOXD1/DKK1 axis may play crucial roles in regulating VM in glioma, which may contribute to the development of potential strategies for the treatment of gliomas.
Assuntos
Neoplasias Encefálicas , Glioma , Camundongos , Animais , Humanos , Neoplasias Encefálicas/metabolismo , Sumoilação , Camundongos Nus , Células Endoteliais/metabolismo , Neovascularização Patológica/genética , Neovascularização Patológica/metabolismo , Glioma/genética , Glioma/metabolismo , Linhagem Celular Tumoral , Ribonucleoproteínas Nucleares Heterogêneas Grupo C/genética , Ribonucleoproteínas Nucleares Heterogêneas Grupo C/metabolismo , Enzimas Ativadoras de Ubiquitina/metabolismo , Peptídeos e Proteínas de Sinalização Intercelular/metabolismo , Fatores de Transcrição Forkhead/genéticaRESUMO
RNA-binding proteins (RBPs), long non-coding RNAs (lncRNAs), and small nucleolar RNAs (snoRNAs) were found to play crucial regulatory roles in ischemic injury. Based on GEO databases and our experimental results, we selected Dcp2, lncRNA-RNCR3, Dkc1, and Snora62 and Foxh1 as research candidates. We found that expression levels of Dcp2, RNCR3, Dkc1, Snora62, and Foxh1 were upregulated in oxygen glucose deprivation-treated HT22 cells and hippocampal tissues subject to chronic cerebral ischemia (CCI). Silencing of Dcp2, RNCR3, Dkc1, Snora62, and Foxh1 all inhibited apoptosis of oxygen glucose deprivation-treated HT22 cells. Moreover, Dcp2 promoted RNCR3 expression by increasing its stability. Importantly, RNCR3 may act as a molecular skeleton to bind to Dkc1 and recruit Dck1 to promote snoRNP assembly. Snora62 was responsible for pseudouridylation at 28S rRNA U3507 and U3509 sites. Pseudouridylation levels of 28S rRNA were reduced after knockdown of Snora62. Decreased pseudouridylation levels inhibited the translational activity of its downstream target, Foxh1. Our study further confirmed that Foxh1 transcriptionally promoted the expression of Bax and Fam162a. Notably, experiments in vivo showed that Dcp2 knockdown combined with RNCR3 knockdown and Snora62 knockdown resulted in an anti-apoptosis effect. In conclusion, this study suggests that the axis Dcp2/RNCR3/Dkc1/Snora621 is important for the regulation of neuronal apoptosis induced by CCI.
Assuntos
Isquemia Encefálica , MicroRNAs , RNA Longo não Codificante , Humanos , MicroRNAs/genética , RNA Ribossômico 28S , Isquemia Encefálica/genética , Isquemia Encefálica/metabolismo , Apoptose/genética , Glucose , Oxigênio , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismoRESUMO
The flhDC operon of Escherichia coli encodes a transcription factor that initiates flagella synthesis, elevates flagella construction and enhances cell motility, which all are energetically costly and highly regulated processes. In this study, we found that overexpression of flhDC genes from a strong regulatable pN15E6 plasmid could inhibit the growth of E. coli host cells and even eventually cause death. We used transcriptome analysis to investigate the mechanism of flhDC overexpression lethal to host bacteria. The results showed that a total of 568 differentially expressed genes (DEGs), including 378 up-regulated genes and 190 down-regulated genes were detected when the flhDC genes were over-expressed. Functional enrichment analysis results showed that the DEGs are related to a series of crucial biomolecular processes, including flagella synthesis, oxidative phosphorylation and pentose phosphate pathways, etc. We then examined, using RT-qPCR, the expression of key genes of the oxidative phosphorylation pathway at different time points after induction. Results showed that their expression increased in the early stage and decreased afterward, which was suggested to be the result of feedback on the overproduction of ROS, a strong side effect product of the elevated oxidative phosphorylation process. To further verify the level of ROS output, flhDC over-expressed bacteria cells were stained with DCHF-DA and a fluorescence signal was detected using flow cytometry. Results showed that the level of ROS output was higher in cells with over-expressed flhDC than in normal controls. Besides, we found upregulation of other genes (recN and zwf) that respond to ROS damage. This leads to the conclusion that the bacterial death led by the overexpression of flhDC genes is caused by damage from ROS overproduction, which leaked from the oxidative phosphorylation pathway.
Assuntos
Proteínas de Escherichia coli , Escherichia coli , Escherichia coli/genética , Escherichia coli/metabolismo , Proteínas de Escherichia coli/genética , Proteínas de Escherichia coli/metabolismo , Transativadores/metabolismo , Espécies Reativas de Oxigênio/metabolismo , Genes Reguladores , Perfilação da Expressão Gênica , Flagelos/metabolismo , Regulação Bacteriana da Expressão Gênica , Proteínas de Bactérias/metabolismoRESUMO
Organic farming supports higher biodiversity than conventional farming, but at the cost of lower yields. We conducted a meta-analysis quantifying the trade-off between biodiversity and yield, comparing conventional and organic farming. We developed a compatibility index to assess whether biodiversity gains from organic farming exceed yield losses, and a substitution index to assess whether organic farming would increase biodiversity in an area if maintaining total production under organic farming would require cultivating more land at the expense of nature. Overall, organic farming had 23% gain in biodiversity with a similar cost of yield decline. Biodiversity gain is negatively correlated to yield loss for microbes and plants, but no correlation was found for other taxa. The biodiversity and yield trade-off varies under different contexts of organic farming. The overall compatibility index value was close to zero, with negative values for cereal crops, positive for non-cereal crops, and varies across taxa. Our results indicate that, on average, the proportion of biodiversity gain is similar to the proportion of yield loss for paired field studies. For some taxa in non-cereal crops, switching to organic farming can lead to a biodiversity gain without yield loss. We calculated the overall value of substitution index and further discussed the application of this index to evaluate when the biodiversity of less intensified farming system is advantageous.
Assuntos
Biodiversidade , Agricultura Orgânica , Agricultura/métodos , Produtos Agrícolas , Agricultura Orgânica/métodosRESUMO
Acquiring the 3D geometry of objects has been an active research topic, wherein the reconstruction of transparent objects poses a great challenge. In this paper, we present a fully automatic approach for reconstructing the exterior surface of a complex transparent scene. Through scanning a line laser by a galvo-mirror, images of the scene are captured from two viewing directions. Due to the light transmission inside the transparent object, the captured feature points and the calibrated laser plane can produce large number of 3D point candidates with large incorrect points through direct triangulation. Various situations of laser transmission inside the transparent object are analyzed and the reconstructed 3D laser point candidates are classified into two types: first-reflection points and non-first-reflection points. The first-reflection points means the first reflected laser points on the front surface of measured objects. Then, a novel four-layers refinement process is proposed to extract the first-reflection points step by step from the 3D point candidates through optical geometric constraints, including (1) Layer-1 : fake points removed by single camera, (2) Layer-2 : ambiguity points removed by the dual-camera joint constraint, (3) Layer-3 : retrieve the missing first-reflection exterior surface points by fusion and (4) Layer-4 : severe ambiguity points removed by contour-continuity. Besides, a novel calibration model about this imaging system is proposed for 3D point candidates reconstruction through triangulation. Compared with traditional laser scanning method, we pulled in the viewing angle information of the second camera and a novel four-layers refinement process is adopted for reconstruction of transparent objects. Various experiments on real objects demonstrate that proposed method can successfully extract the first-reflection points from the candidates and recover the complex shapes of transparent and semitransparent objects.
RESUMO
Surgical robots have been widely adopted with over 4000 robots being used in practice daily. However, these are telerobots that are fully controlled by skilled human surgeons. Introducing "surgeon-assist"-some forms of autonomy-has the potential to reduce tedium and increase consistency, analogous to driver-assist functions for lanekeeping, cruise control, and parking. This article examines the scientific and technical backgrounds of robotic autonomy in surgery and some ethical, social, and legal implications. We describe several autonomous surgical tasks that have been automated in laboratory settings, and research concepts and trends.
RESUMO
Human use of the land (for agriculture and settlements) has a substantial negative effect on biodiversity globally. However, not all species are adversely affected by land use, and indeed, some benefit from the creation of novel habitat. Geographically rare species may be more negatively affected by land use than widespread species, but data limitations have so far prevented global multi-clade assessments of land-use effects on narrow-ranged and widespread species. We analyse a large, global database to show consistent differences in assemblage composition. Compared with natural habitat, assemblages in disturbed habitats have more widespread species on average, especially in urban areas and the tropics. All else being equal, this result means that human land use is homogenizing assemblage composition across space. Disturbed habitats show both reduced abundances of narrow-ranged species and increased abundances of widespread species. Our results are very important for biodiversity conservation because narrow-ranged species are typically at higher risk of extinction than widespread species. Furthermore, the shift to more widespread species may also affect ecosystem functioning by reducing both the contribution of rare species and the diversity of species' responses to environmental changes among local assemblages.
Assuntos
Agricultura/métodos , Biodiversidade , Conservação dos Recursos Naturais/métodos , Animais , Ecossistema , Humanos , Recursos NaturaisRESUMO
RNA-binding proteins (RBPs) are significantly dysregulated in glioma. In this study, we demonstrated the upregulation of Nuclear cap-binding subunit 3 (NCBP3) in glioma tissues and cells. Further, knockdown of NCBP3 inhibited the malignant progression of glioma. NCBP3 directly bound to small nucleolar RNA host gene 6 (SNHG6) and stabilized SNHG6 expression. In contrast, the gastrulation brain homeobox 2 (GBX2) transcription factor was downregulated in glioma tissues and cells. SNHG6 inhibited GBX2 transcription by mediating the H3K27me3 modification induced by polycomb repressive complex 2 (PRC2). Moreover, GBX2 decreased the promoter activities and downregulated the expression of the flotillin protein family 1 (FLOT1) oncogene. In conclusion, NCBP3/SNHG6 inhibits GBX2 transcription in a PRC2-dependent manner to facilitate the malignant progression of gliomas.
Assuntos
Regulação Neoplásica da Expressão Gênica , Glioma/genética , Glioma/metabolismo , Histonas/metabolismo , Proteínas de Homeodomínio/genética , Interferência de RNA , RNA Longo não Codificante/genética , Linhagem Celular Tumoral , Progressão da Doença , Técnicas de Silenciamento de Genes , Glioma/patologia , Humanos , Gradação de Tumores , Estadiamento de Neoplasias , Regiões Promotoras Genéticas , Ligação Proteica , Transcrição Gênica , Proteínas Supressoras de Tumor/genética , Proteínas Supressoras de Tumor/metabolismoRESUMO
Studies have found that RNA-binding proteins (RBPs) and long non-coding RNAs (lncRNAs) are dysregulated and play an important regulatory role in the development of tumors. Based on The Cancer Genome Atlas (TCGA) database, our findings from experiments, and the evidence of previous studies, we screened DiGeorge syndrome critical region gene 8 (DGCR8), ZFAT antisense RNA 1 (ZFAT-AS1), and caudal type homeobox 2 (CDX2) as research candidates. In the present study, DGCR8 and CDX2 were highly expressed and ZFAT-AS1 was markedly downregulated in glioma tissues and cells. DGCR8 or CDX2 knockdown or ZFAT-AS1 overexpression suppressed glioma cell proliferation, migration, and invasion and facilitated apoptosis. DGCR8 might decrease ZFAT-AS1 expression by attenuating its stability in a manner of inducing its cleavage. Importantly, ZFAT-AS1 could inhibit CDX2 transcription by mediating the methylation of histone H3 on lysine 27 (H3K27me3) modification induced by PRC2 in the CDX2 promoter region. In addition, CDX2 transcriptionally activated DGCR8 expression by binding to its promoter regions, forming a positive feedback loop of DGCR8/ZFAT-AS1/CDX2. In conclusion, DGCR8/ZFAT-AS1 promotes CDX2 transcription in a PRC2 complex-dependent manner to facilitate the malignant biological behavior of glioma cells.
Assuntos
Fator de Transcrição CDX2/genética , Regulação Neoplásica da Expressão Gênica , Glioma/genética , RNA Antissenso , RNA Longo não Codificante/genética , Proteínas de Ligação a RNA/genética , Fatores de Transcrição/genética , Animais , Apoptose/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Modelos Animais de Doenças , Técnicas de Silenciamento de Genes , Glioma/metabolismo , Glioma/mortalidade , Glioma/patologia , Humanos , Camundongos , Regiões Promotoras Genéticas , Ligação Proteica , Ensaios Antitumorais Modelo de XenoenxertoRESUMO
Catalases are a large group of enzymes that decompose hydrogen peroxide to oxygen and hydrogen, and have been applied widely in numerous areas. Bacillus subtilis ATCC 6051a is a well-known host strain for high level secretion of heterologous peptides. However, the application of 6051a was seriously hampered by insufficient transformation efficiency. In this study, D-xylose inducible comK was integrated into the genome of B. subtilis ATCC 6051a, generating 164S, a mutant owns a transformation efficiency of 1 000-fold higher than its parent strain, thus allowing gene replacement by double crossover recombination using linear dsDNAs. The efficiency of the flanking arms for homologous recombination was then analyzed. We found that 400 bp was the minimal length of homologous fragments required to initiate efficient recombination in the 164S strain. In addition, DNA cassettes encoding two mesophilic catalases (Orf 2-62 and Orf 2-63) from B. licheniformis were integrated onto 164S. The catalytic properties of recombinant Orf 2-62 and Orf 2-63 were analyzed, and were found to be predominantly secreted into the fermentation broth, although they obviously lack any known secretory signal peptide. This work demonstrated that B. subtilis 164S is an excellent cell tool, not only for its superior secretion capacity, but also for its convenience in genetic modification.
Assuntos
Bacillus subtilis/genética , Bacillus subtilis/metabolismo , Catalase/biossíntese , Bacillus licheniformis/genética , Proteínas de Bactérias/genética , Fermentação , Engenharia Genética , Genoma Bacteriano , Recombinação Homóloga , Microbiologia Industrial , Proteínas Recombinantes/biossíntese , Fatores de Transcrição/genética , Transformação Bacteriana , Xilose/metabolismoRESUMO
Chronic stress is one of the main risk factors of bone loss. While the neurons and neural circuits of the ventromedial hypothalamus (VMH) mediate bone loss induced by chronic stress, the detailed intrinsic mechanisms within the VMH nucleus still need to be explored. Astrocytes in brain regions play important roles in the regulation of metabolism and anxiety-like behavior through interactions with surrounding neurons. However, whether astrocytes in the VMH affect neuronal activity and therefore regulate chronic stress-induced anxiety and bone loss remain elusive. In this study, we found that VMH astrocytes were activated during chronic stress-induced anxiety and bone loss. Pharmacogenetic activation of the Gi and Gq pathways in VMH astrocytes reduced and increased the levels of anxiety and bone loss, respectively. Furthermore, activation of VMH astrocytes by optogenetics induced depolarization in neighboring steroidogenic factor-1 (SF-1) neurons, which was diminished by administration of N-methyl-D-aspartic acid (NMDA) receptor blocker but not by alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptor blocker. These results suggest that there may be a functional "glial-neuron microcircuit" in VMH nuclei that mediates anxiety and bone loss induced by chronic stress. This study not only advances our understanding of glial cell function but also provides a potential intervention target for chronic stress-induced anxiety and bone loss therapy.
Assuntos
Transtornos de Ansiedade/fisiopatologia , Astrócitos/fisiologia , Reabsorção Óssea/fisiopatologia , Estresse Psicológico/complicações , Núcleo Hipotalâmico Ventromedial/patologia , Animais , Astrócitos/efeitos dos fármacos , Astrócitos/metabolismo , Densidade Óssea , Reabsorção Óssea/etiologia , Reabsorção Óssea/prevenção & controle , Doença Crônica , Clozapina/farmacologia , Clozapina/uso terapêutico , Teste de Labirinto em Cruz Elevado , Emoções , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/agonistas , Subunidades alfa Gi-Go de Proteínas de Ligação ao GTP/fisiologia , Subunidades alfa Gq-G11 de Proteínas de Ligação ao GTP/fisiologia , Genes Reporter , Masculino , Camundongos , Camundongos Endogâmicos C57BL , Neurônios/fisiologia , Teste de Campo Aberto , Optogenética , Proteínas Proto-Oncogênicas c-fos/biossíntese , Proteínas Proto-Oncogênicas c-fos/genética , Distribuição Aleatória , Receptores de N-Metil-D-Aspartato/fisiologia , Núcleo Hipotalâmico Ventromedial/fisiopatologiaRESUMO
Increasing evidence has suggested that gliomas can supply blood through vasculogenic mimicry. In this study, the expression and function of ZNRD1-AS1-144aa-uORF (144aa-uORF) and some non-coding RNAs in gliomas were assessed. Real-time quantitative PCR or Western blot was used to discover the expression of 144aa-uORF, ZNRD1-AS1, miR-499a-5p, ELF1 and EMI1 in gliomas. In addition, RIP and RNA pull-down assays were applied to explore the interrelationship between 144aa-uORF and ZNRD1-AS1. The role of the 144aa-uORF\ZNRD1-AS1\miR-499a-5p\ELF1\EMI1 axis in vasculogenic mimicry formation of gliomas was analysed. This study illustrates the reduced expression of the 144aa-uORF in glioma tissues and cells. Up-regulation of 144aa-uORF inhibits proliferation, migration, invasion and vasculogenic mimicry formation within glioma cells. The up-regulated 144aa-uORF can increase the degradation of ZNRD1-AS1 through the nonsense-mediated RNA decay (NMD) pathway. Knockdown of ZNRD1-AS1 inhibits vasculogenic mimicry in glioma cells by modulating miR-499a-5p. At the same time, miR-499a-5p is down-regulated and has a tumour-suppressive effect in gliomas. In addition, ZNRD1-AS1 serves as a competitive endogenous RNA (ceRNA) and regulates the expression of ELF1 by binding to miR-499a-5p. Notably, ELF1 binds to the promoter region of EMI1 and up-regulates EMI1 expression, while simultaneously promoting vasculogenic mimicry in glioma cells. This study suggests that the 144aa-uORF\ZNRD1-AS1\miR-499a-5p\ELF1\EMI1 axis takes key part in regulating the formation of vasculogenic mimicry in gliomas and may provide a potential target for glioma treatment.