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Plasmodium species, the causative agent of malaria, rely on glucose for energy supply during blood stage. Inhibition of glucose uptake thus represents a potential strategy for the development of antimalarial drugs. Here, we present the crystal structures of PfHT1, the sole hexose transporter in the genome of Plasmodium species, at resolutions of 2.6 Å in complex with D-glucose and 3.7 Å with a moderately selective inhibitor, C3361. Although both structures exhibit occluded conformations, binding of C3361 induces marked rearrangements that result in an additional pocket. This inhibitor-binding-induced pocket presents an opportunity for the rational design of PfHT1-specific inhibitors. Among our designed C3361 derivatives, several exhibited improved inhibition of PfHT1 and cellular potency against P. falciparum, with excellent selectivity to human GLUT1. These findings serve as a proof of concept for the development of the next-generation antimalarial chemotherapeutics by simultaneously targeting the orthosteric and allosteric sites of PfHT1.
Assuntos
Proteínas de Transporte de Monossacarídeos/ultraestrutura , Plasmodium falciparum/metabolismo , Plasmodium falciparum/ultraestrutura , Proteínas de Protozoários/ultraestrutura , Sequência de Aminoácidos , Animais , Antimaláricos , Transporte Biológico , Glucose/metabolismo , Humanos , Malária , Malária Falciparum/parasitologia , Proteínas de Transporte de Monossacarídeos/química , Proteínas de Transporte de Monossacarídeos/metabolismo , Parasitos , Plasmodium falciparum/genética , Proteínas de Protozoários/química , Proteínas de Protozoários/metabolismo , Açúcares/metabolismoRESUMO
The newly identified type VII CRISPR-Cas candidate system uses a CRISPR RNA-guided ribonucleoprotein complex formed by Cas5 and Cas7 proteins to target RNA1. However, the RNA cleavage is executed by a dedicated Cas14 nuclease, which is distinct from the effector nucleases of the other CRISPR-Cas systems. Here we report seven cryo-electron microscopy structures of the Cas14-bound interference complex at different functional states. Cas14, a tetrameric protein in solution, is recruited to the Cas5-Cas7 complex in a target RNA-dependent manner. The N-terminal catalytic domain of Cas14 binds a stretch of the substrate RNA for cleavage, whereas the C-terminal domain is primarily responsible for tethering Cas14 to the Cas5-Cas7 complex. The biochemical cleavage assays corroborate the captured functional conformations, revealing that Cas14 binds to different sites on the Cas5-Cas7 complex to execute individual cleavage events. Notably, a plugged-in arginine of Cas7 sandwiched by a C-shaped clamp of C-terminal domain precisely modulates Cas14 binding. More interestingly, target RNA cleavage is altered by a complementary protospacer flanking sequence at the 5' end, but not at the 3' end. Altogether, our study elucidates critical molecular details underlying the assembly of the interference complex and substrate cleavage in the type VII CRISPR-Cas system, which may help rational engineering of the type VII CRISPR-Cas system for biotechnological applications.
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Night-migratory songbirds are remarkably proficient navigators1. Flying alone and often over great distances, they use various directional cues including, crucially, a light-dependent magnetic compass2,3. The mechanism of this compass has been suggested to rely on the quantum spin dynamics of photoinduced radical pairs in cryptochrome flavoproteins located in the retinas of the birds4-7. Here we show that the photochemistry of cryptochrome 4 (CRY4) from the night-migratory European robin (Erithacus rubecula) is magnetically sensitive in vitro, and more so than CRY4 from two non-migratory bird species, chicken (Gallus gallus) and pigeon (Columba livia). Site-specific mutations of ErCRY4 reveal the roles of four successive flavin-tryptophan radical pairs in generating magnetic field effects and in stabilizing potential signalling states in a way that could enable sensing and signalling functions to be independently optimized in night-migratory birds.
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Migração Animal , Criptocromos/genética , Campos Magnéticos , Aves Canoras , Animais , Proteínas Aviárias/genética , Galinhas , Columbidae , RetinaRESUMO
Double-stranded DNA is recognized as a danger signal by cyclic guanosine monophosphate-adenosine monophosphate synthase (cGAS), triggering innate immune responses. Palmitoylation is an important post-translational modification (PTM) catalyzed by DHHC-palmitoyl transferases, which participate in the regulation of diverse biological processes. However, whether palmitoylation regulates cGAS function has not yet been explored. Here, we found that palmitoylation of cGAS at C474 restricted its enzymatic activity in the presence of double-stranded DNA. cGAS palmitoylation was catalyzed mainly by the palmitoyltransferase ZDHHC18 and double-stranded DNA promoted this modification. Mechanistically, palmitoylation of cGAS reduced the interaction between cGAS and double-stranded DNA, further inhibiting cGAS dimerization. Consistently, ZDHHC18 negatively regulated cGAS activation in human and mouse cell lines. In a more biologically relevant model system, Zdhhc18-deficient mice were found to be resistant to infection by DNA viruses, in agreement with the observation that ZDHHC18 negatively regulated cGAS mediated innate immune responses in human and mouse primary cells. In summary, the negative role of ZDHHC18-mediated cGAS palmitoylation may be a novel regulatory mechanism in the fine-tuning of innate immunity.
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Lipoilação , Transdução de Sinais , Animais , Camundongos , DNA/metabolismo , Imunidade Inata , Nucleotidiltransferases/metabolismo , Transdução de Sinais/genéticaRESUMO
DNA and histone modifications have notable effects on gene expression1. Being the most prevalent internal modification in mRNA, the N6-methyladenosine (m6A) mRNA modification is as an important post-transcriptional mechanism of gene regulation2-4 and has crucial roles in various normal and pathological processes5-12. However, it is unclear how m6A is specifically and dynamically deposited in the transcriptome. Here we report that histone H3 trimethylation at Lys36 (H3K36me3), a marker for transcription elongation, guides m6A deposition globally. We show that m6A modifications are enriched in the vicinity of H3K36me3 peaks, and are reduced globally when cellular H3K36me3 is depleted. Mechanistically, H3K36me3 is recognized and bound directly by METTL14, a crucial component of the m6A methyltransferase complex (MTC), which in turn facilitates the binding of the m6A MTC to adjacent RNA polymerase II, thereby delivering the m6A MTC to actively transcribed nascent RNAs to deposit m6A co-transcriptionally. In mouse embryonic stem cells, phenocopying METTL14 knockdown, H3K36me3 depletion also markedly reduces m6A abundance transcriptome-wide and in pluripotency transcripts, resulting in increased cell stemness. Collectively, our studies reveal the important roles of H3K36me3 and METTL14 in determining specific and dynamic deposition of m6A in mRNA, and uncover another layer of gene expression regulation that involves crosstalk between histone modification and RNA methylation.
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Adenosina/análogos & derivados , Histonas/química , Histonas/metabolismo , Lisina/metabolismo , RNA Mensageiro/química , RNA Mensageiro/metabolismo , Transcrição Gênica , Adenosina/metabolismo , Animais , Diferenciação Celular , Linhagem Celular , Células-Tronco Embrionárias/metabolismo , Humanos , Lisina/química , Metilação , Metiltransferases/deficiência , Metiltransferases/genética , Metiltransferases/metabolismo , Camundongos , RNA Polimerase II/metabolismo , Elongação da Transcrição Genética , Transcriptoma/genéticaRESUMO
CRISPR-Cas systems act as the adaptive immune systems of bacteria and archaea, targeting and destroying invading foreign mobile genetic elements (MGEs) such as phages. MGEs have also evolved anti-CRISPR (Acr) proteins to inactivate the CRISPR-Cas systems. Recently, AcrIIC4, identified from Haemophilus parainfluenzae phage, has been reported to inhibit the endonuclease activity of Cas9 from Neisseria meningitidis (NmeCas9), but the inhibition mechanism is not clear. Here, we biochemically and structurally investigated the anti-CRISPR activity of AcrIIC4. AcrIIC4 folds into a helix bundle composed of three helices, which associates with the REC lobe of NmeCas9 and sgRNA. The REC2 domain of NmeCas9 is locked by AcrIIC4, perturbing the conformational dynamics required for the target DNA binding and cleavage. Furthermore, mutation of the key residues in the AcrIIC4-NmeCas9 and AcrIIC4-sgRNA interfaces largely abolishes the inhibitory effects of AcrIIC4. Our study offers new insights into the mechanism of AcrIIC4-mediated suppression of NmeCas9 and provides guidelines for the design of regulatory tools for Cas9-based gene editing applications.
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Bacteriófagos , Sistemas CRISPR-Cas , Sistemas CRISPR-Cas/genética , Proteína 9 Associada à CRISPR/metabolismo , RNA Guia de Sistemas CRISPR-Cas , Edição de Genes , Bactérias/genética , Bacteriófagos/genéticaRESUMO
Palladium (Pd)-based single-atom catalysts (SACs) have shown outstanding selectivity for semihydrogenation of alkynes, but most Pd single sites coordinated with highly electronegative atoms (such as N, O, and S) of supports will result in a decrease in the electron density of Pd sites, thereby weakening the adsorption of reactants and reducing catalytic performance. Constructing a rich outer-shell electron environment of Pd single-atom sites by changing the coordination structure offers a novel opportunity to enhance the catalytic efficiency with excellent alkene selectivity. Therefore, in this work, we first propose the in situ preparation of isolated Pd sites encapsulated within Al/Si-rich ZSM-5 structure using the one-pot seed-assisted growth method. Pd1@ZSM-5 features Pd-O-Al/Si bonds, which can boost the domination of d-electron near the Fermi level, thereby promoting the adsorption of substrates on Pd sites and reducing the energy barrier for the semihydrogenation of alkynes. In semihydrogenation of phenylacetylene, Pd1@ZSM-5 catalyst performs the highest turnover frequency (TOF) value of 33582 molCâC/molPd/h with 96% selectivity of styrene among the reported heterogeneous catalysts and nearly 17-fold higher than that of the commercial Lindlar catalyst (1992 molCâC/molPd/h). This remarkable catalytic performance can be retained even after 6 cycles of usage. Particularly, the zeolitic confinement structure of Pd1@ZSM-5 enables precise shape-selective catalysis for alkyne reactants with a size less than 4.3 Å.
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The direct pyrolysis of metal-zeolite imidazolate frameworks (M-ZIFs) has been widely recognized as the predominant approach for synthesizing atomically dispersed metal-nitrogen-carbon single-atom catalysts (M/NC-SACs), which have exhibited exceptional activity and selectivity in the semihydrogenation of acetylene. However, due to weak adsorption of reactants on the single site and restricted molecular diffusion, the semihydrogenation of large organic molecules (e.g., phenylacetylene) was greatly limited for M/NC-SACs. In this work, a dual single-atom catalyst (h-Pd-Mn/NC) with hollow mesopores was designed and prepared using a general host-guest strategy. Taking the semihydrogenation of phenylacetylene as an example, this catalyst exhibited ultrahigh activity and selectivity, which achieved a turnover frequency of 218 molCâCmolPd-1 min-1, 16-fold higher than that of the commercial Lindlar catalyst. The catalyst maintained high activity and selectivity even after 5 cycles of usage. The superior activity of h-Pd-Mn/NC was attributed to the 4.0 nm mesopore interface of the catalyst, which enhanced the diffusion of macromolecular reactants and products. Particularly, the introduction of atomically dispersed Mn with weak electronegativity in h-Pd-Mn/NC could drive the electron transfer from Mn to adjacent Pd sites and regulate the electronic structure of Pd sites. Meanwhile, the strong electronic coupling in Pd-Mn pairs enhanced the d-electron domination near the Fermi level and promoted the adsorption of phenylacetylene and H2 on Pd active sites, thereby reducing the energy barrier for the semihydrogenation of phenylacetylene.
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Despite the extensive development of non-noble metals for the N-alkylation of amines with alcohols, the exploitation of catalysts with high selectivity, activity, and stability still faces challenges. The controllable modification of single-atom sites through asymmetric coordination with a second heteroatom offers new opportunities for enhancing the intrinsic activity of transition metal single-atom catalysts. Here, we prepared the asymmetric N/P hybrid coordination of single-atom Co1-N3P1 by absorbing the Co-P complex on ZIF-8 using a concise impregnation-pyrolysis process. The catalyst exhibits ultrahigh activity and selectivity in the N-alkylation of aniline and benzyl alcohol, achieving a turnover number (TON) value of 3480 and a turnover frequency (TOF) value of 174-h. The TON value is 1 order of magnitude higher than the reported catalysts and even 37-fold higher than that of the homogeneous catalyst CoCl2(PPh3)2. Furthermore, the catalyst maintains its high activity and selectivity even after 6 cycles of usage. Controlling experiments and isotope labeling experiments confirm that in the asymmetric Co1-N3P1 system, the N-alkylation of aniline with benzyl alcohol proceeds via a transfer hydrogenation mechanism involving the monohydride route. Theoretical calculations prove that the superior activity of asymmetric Co1-N3P1 is attributed to the higher d-band energy level of Co sites, which leads to a more stable four-membered ring transition state and a lower reaction energy barrier compared to symmetrical Co1-N4.
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In brief: SORBS2, an RNA-binding protein, is identified as a regulator of aerobic glycolysis, which is essential for trophoblast migration and placental development. Reduced SORBS2 expression in preeclampsia may impair trophoblast migration by affecting mRNA stability and glycolysis, suggesting its role in the disease's pathogenesis. Abstract: Insufficient trophoblast migration and impaired uterine spiral artery remodeling are implicated in the pathogenesis of preeclampsia, contributing to inadequate placentation. However, the molecular mechanism underlying this process remains unclear. Aerobic glycolysis, which produces substantial lactate, is crucial for establishing a favorable microenvironment for early uterine preparation and supporting embryo implantation and trophoblast migration. In the present study, we have demonstrated that SORBS2, an RNA-binding protein, regulated aerobic glycolysis and significantly improved trophoblast migration in vitro. Our results showed that SORBS2 expression was significantly reduced in human PE placentas and trophoblasts during hypoxia. Overexpression of SORBS2 enhanced cell proliferation and migration, whereas knockdown of SORBS2 decreased these functions in HTR-8/SVneo cells. Mechanistic studies have demonstrated that SORBS2 directly interacts with the 3' untranslated regions (UTRs) of key glycolysis-related genes, specifically HK2. This interaction results in enhanced stability of HK2 and activation of glycolysis. Moreover, silencing HK2 abrogated the enhancement of proliferation and migration of HTR-8/SVneo cells induced by SORBS2. In conclusion, our findings suggest that the downregulation of SORBS2 may contribute to the pathogenesis of preeclampsia by regulating mRNA stability and inhibiting trophoblast migration during placentation.
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Movimento Celular , Glicólise , Hexoquinase , Pré-Eclâmpsia , Estabilidade de RNA , RNA Mensageiro , Proteínas de Ligação a RNA , Trofoblastos , Humanos , Pré-Eclâmpsia/metabolismo , Pré-Eclâmpsia/genética , Pré-Eclâmpsia/patologia , Trofoblastos/metabolismo , Trofoblastos/patologia , Feminino , Gravidez , Proteínas de Ligação a RNA/metabolismo , Proteínas de Ligação a RNA/genética , RNA Mensageiro/metabolismo , RNA Mensageiro/genética , Hexoquinase/metabolismo , Hexoquinase/genética , Adulto , Proliferação de CélulasRESUMO
BACKGROUND: In the tumor immune microenvironment (TIME), triggering receptor expressed on myeloid cells 2 (trem2) is widely considered to be a crucial molecule on tumor-associated macrophages(TAMs). Multiple studies have shown that trem2 may function as an immune checkpoint in various malignant tumors, mediating tumor immune evasion. However, its specific molecular mechanisms, especially in glioma, remain elusive. METHODS: Lentivirus was transfected to establish cells with stable knockdown of trem2. A Transwell system was used for segregated coculture of glioma cells and microglia. Western blotting, quantitative real-time polymerase chain reaction (qRTâPCR), and immunofluorescence (IF) were used to measure the expression levels of target proteins. The proliferation, invasion, and migration of cells were detected by colony formation, cell counting kit-8 (CCK8), 5-ethynyl-2'-deoxyuridine (EdU) and transwell assays. The cell cycle, apoptosis rate and reactive oxygen species (ROS) level of cells were assessed using flow cytometry assays. The comet assay and tube formation assay were used to detect DNA damage in glioma cells and angiogenesis activity, respectively. Gl261 cell lines and C57BL/6 mice were used to construct the glioma orthotopic transplantation tumor model. RESULTS: Trem2 was highly overexpressed in glioma TAMs. Knocking down trem2 in microglia suppressed the growth and angiogenesis activity of glioma cells in vivo and in vitro. Mechanistically, knockdown of trem2 in microglia promoted proinflammatory microglia and inhibited anti-inflammatory microglia by activating jak2/stat1 and inhibiting the NF-κB p50 signaling pathway. The proinflammatory microglia produced high concentrations of nitric oxide (NO) and high levels of the proinflammatory cytokines TNF-α, IL-6, and IL-1ß, and caused further DNA damage and promoted the apoptosis rate of tumor cells. CONCLUSIONS: Our findings revealed that trem2 in microglia plays a significant role in the TIME of gliomas. Knockdown of trem2 in microglia might help to improve the efficiency of inhibiting glioma growth and delaying tumor progression and provide new ideas for further treatment of glioma.
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Glioma , Glicoproteínas de Membrana , Microglia , Receptores Imunológicos , Transdução de Sinais , Animais , Humanos , Camundongos , Apoptose/genética , Linhagem Celular Tumoral , Movimento Celular/genética , Proliferação de Células/genética , Progressão da Doença , Técnicas de Silenciamento de Genes , Glioma/genética , Glioma/patologia , Glioma/metabolismo , Inflamação/genética , Inflamação/patologia , Janus Quinase 2/genética , Janus Quinase 2/metabolismo , Glicoproteínas de Membrana/genética , Glicoproteínas de Membrana/metabolismo , Camundongos Endogâmicos C57BL , Microglia/metabolismo , Microglia/patologia , NF-kappa B/metabolismo , Receptores Imunológicos/genética , Receptores Imunológicos/metabolismo , Transdução de Sinais/genética , Fator de Transcrição STAT3/metabolismo , Fator de Transcrição STAT3/genéticaRESUMO
AIMS: Androgen receptor inhibitors (ARIs) have become an effective treatment for advanced prostate cancer (PC). However, it is unknown which ARI is the most helpful and safe for men with advanced PC. Our aim is to help physicians make clinical decisions and provide medication guidelines for patients with advanced PC to avoid potential risks when using ARIs for treatment. METHODS: We systematically searched the following databases: PubMed, Embase and Cochrane Library, with a literature publication deadline of February 2023. The primary efficacy outcomes were 18-month overall survival (OS), treatment-emergent adverse events (TEAEs), hypertension and fatigue. The network meta-analysis (NMA) was performed by Stata 15.1, and Revman 5.3 was used to assess the included studies' risk of bias. RESULTS: The analysis included 26 trials with 26 263 people. The surface under the cumulative ranking curve (SUCRA) concluded that enzalutamide (86.8%) showed the best effect in prolonging the OS of patients. Flutamide led to the highest risk of TEAEs (29.9%) and AEs leading to discontinuation (12.8%). Apalutamide (13.4%) led to the highest risk of grade ≥3 TEAEs. Enzalutamide had the highest risk of hypertension (0.2%), grade ≥3 hypertension (4.5%) and fatigue (5.2%). CONCLUSIONS: This NMA indicates there is no one ARI to reach both the most effective and safe therapy aims for treating advanced PC and that there is a compromise between the efficacy and safety of ARIs in the treatment of advanced PC. Physicians should weigh the risks to safety against the anticipated benefits when prescribing these drugs to patients with PC.
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Vehicle emissions have a serious impact on urban air quality and public health, so environmental authorities around the world have introduced increasingly stringent emission regulations to reduce vehicle exhaust emissions. Nowadays, PEMS (Portable Emission Measurement System) is the most widely used method to measure on-road NOx (Nitrogen Oxides) and PN (Particle Number) emissions from HDDVs (Heavy-Duty Diesel Vehicles). However, the use of PEMS requires a lot of workforce and resources, making it both costly and time-consuming. This study proposes a neural network based on a combination of GA (Genetic Algorithm) and GRU (Gated Recurrent Unit), which uses CC (Pearson Correlation Coefficient) to determine and simplify OBD (On-board Diagnosis) data. The GA-GRU model is trained under three real driving conditions of HDDVs, divided by vehicle driving parameters, and then embedded as a soft sensor in the OBD system to monitor real-time emissions of NOx and PN within the OBD system. This research addresses the existing research gap in the development of soft sensors specifically designed for NOx and PN emission monitoring. In this study, it is demonstrated that the described soft sensor has excellent R2 values and outperforms other conventional models. This research highlights the ability of the proposed soft sensor to eliminate outliers accurately and promptly while consistently tracking predictions throughout the vehicle's lifetime. This method is a groundbreaking update to the vehicle's OBD system, permanently adding monitoring data to the vehicle's OBD, thus fundamentally improving the vehicle's self-monitoring capabilities.
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Poluentes Atmosféricos , Poluição do Ar , Emissões de Veículos/análise , Poluentes Atmosféricos/análise , Óxidos de Nitrogênio/análise , Monitoramento Ambiental/métodos , Veículos Automotores , GasolinaRESUMO
OBJECTIVE: Colorectal cancer (CRC) is a form of malignancy that exhibits a comparatively elevated occurrence and fatality rate. Given the relatively slower progress in diagnostic and therapeutic approaches for CRC, there is a need to investigate more accurate and efficient biomarkers. METHODS: Core regulatory genes were screened using the TCGA database, and the expression of neurexophilin 4 (NXPH4) and its prognostic implications were validated using tissue microarray staining. The assessment of NXPH4 functions involved a range of experiments, including cellular, organoid, and murine models. Furthermore, a regulatory network between m5C, NXPH4, and HIF1A was established through several in vitro experiments. RESULTS: The overexpression of NXPH4 is associated with unfavorable prognoses in patients with CRC and hepatocellular carcinoma. Additionally, it facilitates the progression of malignant tumors both in laboratory settings and in living organisms of colorectal carcinoma. Our research also reveals that NXPH4 mRNA can avoid degradation through RNautophagy, relying on an m5C-dependent mechanism. Moreover, NXPH4 amplifies the HIF signaling pathway and stabilizes HIF1A by competitively binding to PHD4. CONCLUSIONS: NXPH4, regulated by m5C, promotes malignant tumor progression and regulates the HIF pathway. Consequently, targeting NXPH4 through molecular therapies could potentially serve as an efficacious therapeutic strategy for the management of CRC exhibiting elevated NXPH4 expression.
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Neoplasias Colorretais , Regulação Neoplásica da Expressão Gênica , Subunidade alfa do Fator 1 Induzível por Hipóxia , Neoplasias Colorretais/metabolismo , Neoplasias Colorretais/genética , Neoplasias Colorretais/patologia , Humanos , Subunidade alfa do Fator 1 Induzível por Hipóxia/metabolismo , Subunidade alfa do Fator 1 Induzível por Hipóxia/genética , Animais , Camundongos , Linhagem Celular Tumoral , Prognóstico , Camundongos Nus , Proteólise , Transdução de Sinais , Proliferação de Células/genética , Camundongos Endogâmicos BALB CRESUMO
BACKGROUND: There are few studies on cryptorchidism in adults, and its treatment is still controversial. METHODS: To summarize the surgical strategy and clinical efficacy of laparoscopic orchidopexy for the treatment of cryptorchidism in adults, 37 adult cryptorchidism patients were retrospectively analyzed between September 2017 and February 2022. All 37 patients underwent laparoscopic orchidopexy, of whom 33 underwent inguinal hernia repair without tension. The intraoperative procedures and surgical techniques were recorded in detail. Preoperative examination and regular postoperative review of color Doppler ultrasound, and reproductive hormone, alpha-fetoprotein, human chorionic gonadotropin, and lactate dehydrogenase levels were performed. RESULTS: All testes descended successfully into the scrotum, including 25 through the inguinal route and 12 through Hesselbach's triangle route. No intraoperative or postoperative complications were observed. The follow-up time was 38.6 (± 19.4) months, and no evidence of testicular malignancy was found during the follow-up period. After analyzing the reproductive hormone levels at 1 year postoperatively in 28 patients with more than 1 year of follow-up, it was found that the patients had a significant increase in testosterone levels and a decrease in follicle-stimulating hormone levels after surgery. None of the patients showed any significant improvement in semen quality after surgery. CONCLUSION: Our study suggests that laparoscopic orchidopexy is a safe and feasible surgical procedure for the treatment of cryptorchidism in adults, especially high cryptorchidism, which is difficult to treat. After comprehensive consideration, preserving the testis should be preferred for treating cryptorchidism in adults to maximize the protection of the patient's reproductive hormone secretion function.
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Criptorquidismo , Laparoscopia , Masculino , Humanos , Lactente , Criptorquidismo/cirurgia , Criptorquidismo/diagnóstico , Orquidopexia/métodos , Estudos Retrospectivos , Análise do Sêmen , Laparoscopia/métodos , Testículo , Resultado do Tratamento , HormôniosRESUMO
Mobile genetic elements such as phages and plasmids have evolved anti-CRISPR proteins (Acrs) to suppress CRISPR-Cas adaptive immune systems. Recently, several phage and non-phage derived Acrs including AcrIIA17 and AcrIIA18 have been reported to inhibit Cas9 through modulation of sgRNA. Here, we show that AcrIIA17 and AcrIIA18 inactivate Cas9 through distinct mechanisms. AcrIIA17 inhibits Cas9 activity through interference with Cas9-sgRNA binary complex formation. In contrast, AcrIIA18 induces the truncation of sgRNA in a Cas9-dependent manner, generating a shortened sgRNA incapable of triggering Cas9 activity. The crystal structure of AcrIIA18, combined with mutagenesis studies, reveals a crucial role of the N-terminal ß-hairpin in AcrIIA18 for sgRNA cleavage. The enzymatic inhibition mechanism of AcrIIA18 is different from those of the other reported type II Acrs. Our results add new insights into the mechanistic understanding of CRISPR-Cas9 inhibition by Acrs, and also provide valuable information in the designs of tools for conditional manipulation of CRISPR-Cas9.
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Bacteriófagos/genética , Sistemas CRISPR-Cas , Edição de Genes/métodos , RNA Guia de Cinetoplastídeos/metabolismo , Proteínas Virais/metabolismoRESUMO
Double-stranded DNA (dsDNA) is recognized as a danger signal by cyclic GMP-AMP synthase (cGAS), which triggers innate immune responses. cGAS activity must be properly regulated to maintain immune homeostasis. However, the mechanism by which cGAS activation is controlled remains to be better understood. In this study, we identified USP15 as a cGAS-interacting partner. USP15 promoted DNA-induced cGAS activation and downstream innate immune responses through a positive feedback mechanism. Specifically, USP15 deubiquitylated cGAS and promoted its activation. In the absence of DNA, USP15 drove cGAS dimerization and liquid condensation through the USP15 intrinsic disordered region (IDR), which prepared cGAS for a rapid response to DNA. Upon DNA stimulation, USP15 was induced to express and boost cGAS activation, functioning as an efficient amplifier in innate immune signal transduction. In summary, the positive role played by USP15-mediated cGAS activation may be a novel regulatory mechanism in the fine-tuning of innate immunity.
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Imunidade Inata , Nucleotidiltransferases , Nucleotidiltransferases/metabolismo , Imunidade Inata/fisiologia , DNA/genética , Transdução de Sinais/genéticaRESUMO
The type III-E CRISPR-Cas systems are newly identified adaptive immune systems in prokaryotes that use a single Cas7-11 protein to specifically cleave target RNA. Cas7-11 could associate with Csx29, a putative caspase-like protein encoded by the gene frequently found in the type III-E loci, suggesting a functional linkage between the RNase and protease activities in type III-E systems. Here, we demonstrated that target RNA recognition would stimulate the proteolytic activity of Csx29, and protein Csx30 is the endogenous substrate. More interestingly, while the cognate target RNA recognition would activate Csx29, non-cognate target RNA with the complementary 3' anti-tag sequence inhibits the enzymatic activity. Csx30 could bind to the sigma factor RpoE, which may initiate the stress response after proteolytic cleavage. Combined with biochemical and structural studies, we have elucidated the mechanisms underlying the target RNA-guided proteolytic activity of Csx29. Our work will guide further developments leveraging this simple RNA targeting system for RNA and protein-related applications.
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Proteínas Associadas a CRISPR , RNA , RNA/genética , Sistemas CRISPR-Cas , Endorribonucleases/metabolismo , Ribonucleases/metabolismo , Peptídeo Hidrolases/genética , Proteínas Associadas a CRISPR/genética , Proteínas Associadas a CRISPR/metabolismoRESUMO
PURPOSE: This study investigated the value of whole tumor apparent diffusion coefficient (ADC) histogram parameters and magnetic resonance imaging (MRI) semantic features in predicting meningioma progesterone receptor (PR) expression. MATERIALS AND METHODS: The imaging, pathological, and clinical data of 53 patients with PR-negative meningiomas and 52 patients with PR-positive meningiomas were retrospectively reviewed. The whole tumor was outlined using Firevoxel software, and the ADC histogram parameters were calculated. The differences in ADC histogram parameters and MRI semantic features were compared between the two groups. The predictive values of parameters for PR expression were assessed using receiver operating characteristic curves. The correlation between whole-tumor ADC histogram parameters and PR expression in meningiomas was also analyzed. RESULTS: Grading was able to predict the PR expression in meningiomas (p = 0.012), though the semantic features of MRI were not (all p > 0.05). The mean, Perc.01, Perc.05, Perc.10, Perc.25, and Perc.50 histogram parameters were able to predict meningioma PR expression (all p < 0.05). The predictive performance of the combined histogram parameters improved, and the combination of grade and histogram parameters provided the optimal predictive value, with an area under the curve of 0.849 (95%CI: 0.766-0.911) and sensitivity, specificity, ACC, PPV, and NPV of 73.08%, 81.13%, 77.14%, 79.20%, and 75.40%, respectively. The mean, Perc.01, Perc.05, Perc.10, Perc.25, and Perc.50 histogram parameters were positively correlated with PR expression (all p < 0.05). CONCLUSION: Whole tumor ADC histogram parameters have additional clinical value in predicting PR expression in meningiomas.
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Imagem de Difusão por Ressonância Magnética , Neoplasias Meníngeas , Meningioma , Receptores de Progesterona , Humanos , Meningioma/diagnóstico por imagem , Meningioma/patologia , Meningioma/metabolismo , Feminino , Pessoa de Meia-Idade , Masculino , Neoplasias Meníngeas/diagnóstico por imagem , Neoplasias Meníngeas/patologia , Neoplasias Meníngeas/metabolismo , Receptores de Progesterona/metabolismo , Adulto , Imagem de Difusão por Ressonância Magnética/métodos , Idoso , Estudos Retrospectivos , Valor Preditivo dos TestesRESUMO
Artemisinin-resistant malaria parasites have emerged and have been spreading, posing a significant public health challenge. Antimalarial drugs with novel mechanisms of action are therefore urgently needed. In this report, we exploit a "selective starvation" strategy by inhibiting Plasmodium falciparum hexose transporter 1 (PfHT1), the sole hexose transporter in P. falciparum, over human glucose transporter 1 (hGLUT1), providing an alternative approach to fight against multidrug-resistant malaria parasites. The crystal structure of hGLUT3, which shares 80% sequence similarity with hGLUT1, was resolved in complex with C3361, a moderate PfHT1-specific inhibitor, at 2.3-Å resolution. Structural comparison between the present hGLUT3-C3361 and our previously reported PfHT1-C3361 confirmed the unique inhibitor binding-induced pocket in PfHT1. We then designed small molecules to simultaneously block the orthosteric and allosteric pockets of PfHT1. Through extensive structure-activity relationship studies, the TH-PF series was identified to selectively inhibit PfHT1 over hGLUT1 and potent against multiple strains of the blood-stage P. falciparum Our findings shed light on the next-generation chemotherapeutics with a paradigm-shifting structure-based design strategy to simultaneously target the orthosteric and allosteric sites of a transporter.