RESUMO
The soluble flavoprotein oleate hydratase (OhyA) hydrates the 9-cis double bond of unsaturated fatty acids. OhyA substrates are embedded in membrane bilayers; OhyA must remove the fatty acid from the bilayer and enclose it in the active site. Here, we show that the positively charged helix-turn-helix motif in the carboxy terminus (CTD) is responsible for interacting with the negatively charged phosphatidylglycerol (PG) bilayer. Super-resolution microscopy of Staphylococcus aureus cells expressing green fluorescent protein fused to OhyA or the CTD sequence shows subcellular localization along the cellular boundary, indicating OhyA is membrane-associated and the CTD sequence is sufficient for membrane recruitment. Using cryo-electron microscopy, we solved the OhyA dimer structure and conducted 3D variability analysis of the reconstructions to assess CTD flexibility. Our surface plasmon resonance experiments corroborated that OhyA binds the PG bilayer with nanomolar affinity and we found the CTD sequence has intrinsic PG binding properties. We determined that the nuclear magnetic resonance structure of a peptide containing the CTD sequence resembles the OhyA crystal structure. We observed intermolecular NOE from PG liposome protons next to the phosphate group to the CTD peptide. The addition of paramagnetic MnCl2 indicated the CTD peptide binds the PG surface but does not insert into the bilayer. Molecular dynamics simulations, supported by site-directed mutagenesis experiments, identify key residues in the helix-turn-helix that drive membrane association. The data show that the OhyA CTD binds the phosphate layer of the PG surface to obtain bilayer-embedded unsaturated fatty acids.
Assuntos
Ácido Oleico , Peptídeos , Staphylococcus aureus , Microscopia Crioeletrônica , Ácidos Graxos Insaturados , Bicamadas Lipídicas/metabolismo , Fosfatos , Staphylococcus aureus/enzimologia , Staphylococcus aureus/genéticaRESUMO
Transporters belonging to the Resistance-Nodulation-cell Division (RND) superfamily of proteins such as Mycobacterium tuberculosis MmpL3 and its analogs are the focus of intense investigations due to their importance in the physiology of Corynebacterium-Mycobacterium-Nocardia species and antimycobacterial drug discovery. These transporters deliver trehalose monomycolates, the precursors of major lipids of the outer membrane, to the periplasm by a proton motive force-dependent mechanism. In this study, we successfully purified, from native membranes, the full-length and the C-terminal truncated M. tuberculosis MmpL3 and Corynebacterium glutamicum CmpL1 proteins and reconstituted them into proteoliposomes. We also generated a series of substrate mimics and inhibitors specific to these transporters, analyzed their activities in the reconstituted proteoliposomes, and carried out molecular dynamics simulations of the model MmpL3 transporter at different pH. We found that all reconstituted proteins facilitate proton translocation across a phospholipid bilayer, but MmpL3 and CmpL1 differ dramatically in their responses to pH and interactions with substrate mimics and indole-2-carboxamide inhibitors. Our results further suggest that some inhibitors abolish the transport activity of MmpL3 and CmpL1 by inhibition of proton translocation.
Assuntos
Proteínas de Bactérias , Proteínas de Membrana Transportadoras , Proteínas de Bactérias/antagonistas & inibidores , Proteínas de Bactérias/química , Corynebacterium , Transporte de Íons , Bicamadas Lipídicas/química , Proteínas de Membrana Transportadoras/química , Ácidos Micólicos/metabolismo , Prótons , Especificidade por SubstratoRESUMO
Cancer immunotherapy is a method of controlling and eliminating tumors by reactivating the body's cancer-immunity cycle and restoring its antitumor immune response. The increased availability of data, combined with advancements in high-performance computing and innovative artificial intelligence (AI) technology, has resulted in a rise in the use of AI in oncology research. State-of-the-art AI models for functional classification and prediction in immunotherapy research are increasingly used to support laboratory-based experiments. This review offers a glimpse of the current AI applications in immunotherapy, including neoantigen recognition, antibody design, and prediction of immunotherapy response. Advancing in this direction will result in more robust predictive models for developing better targets, drugs, and treatments, and these advancements will eventually make their way into the clinical setting, pushing AI forward in the field of precision oncology.
Assuntos
Inteligência Artificial , Neoplasias , Humanos , Neoplasias/terapia , Medicina de Precisão/métodos , Oncologia , ImunoterapiaRESUMO
Interferon regulatory factor 4 (IRF4) is a crucial transcription factor that plays a vital role in lymphocyte development, including in the fate-determining steps in terminal differentiation. It is also implicated in the development of lymphoid tumors such as multiple myeloma and adult T-cell leukemia. IRF4 can form a homodimer and multiple heterocomplexes with other transcription factors such as purine-rich box1 and activator protein 1. Each protein complex binds to specific DNA sequences to regulate a distinct set of genes. However, the precise relationship among these complex formations remains unclear. Herein, we investigated the abilities of IRF4 proteins with functional mutations in the IRF-association domain and autoinhibitory region to form complexes using luciferase reporter assays. The assays allowed us to selectively assess the activity of each complex. Our results revealed that certain IRF-association domain mutants, previously known to have impaired heterocomplex formation, maintained or even enhanced homodimer activity. This discrepancy suggests that the mutated amino acid residues selectively influence homodimer activity. Conversely, a phosphomimetic serine mutation in the autoinhibitory region displayed strong activating effects in all complexes. Furthermore, we observed that partner proteins involved in heterocomplex formation could disrupt the activity of the homodimer, suggesting a potential competition between homocomplexes and heterocomplexes. Our findings provide new insights into the mechanistic function of IRF4.
Assuntos
Regulação da Expressão Gênica , Fatores Reguladores de Interferon , Sequência de Bases , Fator Regulador 3 de Interferon/genética , Fator Regulador 3 de Interferon/metabolismo , Fatores Reguladores de Interferon/genética , Fatores Reguladores de Interferon/metabolismo , Mutação , Fator de Transcrição AP-1/metabolismo , Humanos , Células HEK293RESUMO
Cryptochromes (CRYs) act as blue light photoreceptors to regulate various plant physiological processes including photomorphogenesis and repair of DNA double strand breaks (DSBs). ADA2b is a conserved transcription co-activator that is involved in multiple plant developmental processes. It is known that ADA2b interacts with CRYs to mediate blue light-promoted DSBs repair. Whether ADA2b may participate in CRYs-mediated photomorphogenesis is unknown. Here we show that ADA2b acts to inhibit hypocotyl elongation and hypocotyl cell elongation in blue light. We found that the SWIRM domain-containing C-terminus mediates the blue light-dependent interaction of ADA2b with CRYs in blue light. Moreover, ADA2b and CRYs act to co-regulate the expression of hypocotyl elongation-related genes in blue light. Based on previous studies and these results, we propose that ADA2b plays dual functions in blue light-mediated DNA damage repair and photomorphogenesis.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Regulação da Expressão Gênica de Plantas , Hipocótilo , Luz , Arabidopsis/genética , Arabidopsis/crescimento & desenvolvimento , Arabidopsis/efeitos da radiação , Arabidopsis/metabolismo , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Regulação da Expressão Gênica de Plantas/efeitos da radiação , Hipocótilo/crescimento & desenvolvimento , Hipocótilo/metabolismo , Hipocótilo/efeitos da radiação , Hipocótilo/genética , Criptocromos/metabolismo , Criptocromos/genética , Reparo do DNA/efeitos da radiação , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genética , Morfogênese/efeitos da radiação , Luz AzulRESUMO
Cryptochromes (CRYs) are blue light (BL) photoreceptors to regulate a variety of physiological processes including DNA double-strand break (DSB) repair. SUPPRESSOR OF GAMMA RADIATION 1 (SOG1) acts as the central transcription factor of DNA damage response (DDR) to induce the transcription of downstream genes, including DSB repair-related genes BRCA1 and RAD51. Whether CRYs regulate DSB repair by directly modulating SOG1 is unknown. Here, we demonstrate that CRYs physically interact with SOG1. Disruption of CRYs and SOG1 leads to increased sensitivity to DSBs and reduced DSB repair-related genes' expression under BL. Moreover, we found that CRY1 enhances SOG1's transcription activation of DSB repair-related gene BRCA1. These results suggest that the mechanism by which CRYs promote DSB repair involves positive regulation of SOG1's transcription of its target genes, which is likely mediated by CRYs-SOG1 interaction.
Assuntos
Proteínas de Arabidopsis , Arabidopsis , Criptocromos , Quebras de DNA de Cadeia Dupla , Reparo do DNA , Proteínas de Arabidopsis/metabolismo , Proteínas de Arabidopsis/genética , Arabidopsis/genética , Arabidopsis/metabolismo , Criptocromos/metabolismo , Criptocromos/genética , Regulação da Expressão Gênica de Plantas , Fatores de Transcrição/metabolismo , Fatores de Transcrição/genéticaRESUMO
Porcine epidemic diarrhea virus (PEDV) is an enteric coronavirus that has been the main cause of diarrhea in piglets since 2010 in China. The aim of this study was to investigate sequence variation and recombination events in the spike (S) gene of PEDV isolates from China. Thirty complete S gene sequences were obtained from PEDV-positive samples collected in six provinces in China from 2020 to 2023. Phylogenetic analysis showed that 10% (3/30) belonged to subtype GII-a, 6.67% (2/30) were categorized as subtype GII-b, 66.67% (20/30) were categorized as subtype GII-c, and 16.66% (5/30) were clustered with the S-INDEL strains. Amino acid sequence alignments showed that, when compared to strains of other subtypes, the GII-c strains had two characteristic amino acid substitutions (N139D and I289M). Five S-INDEL subtype strains had a single amino acid deletion (139N) and four amino acid substitutions (N118G, T137S, A138S, and D141G). Recombination analysis allowed six putative recombination events to be identified, one involving recombination between GII-c strains, two involving GII-c and GII-b strains, two involving GII-c and GI-a strains, and one involving GII-a and GI-b strains. These results suggest that recombination between PEDV strains has been common and complex in recent years and is one of the main reasons for the continuous variation of PEDV strains.
Assuntos
Infecções por Coronavirus , Filogenia , Vírus da Diarreia Epidêmica Suína , Recombinação Genética , Glicoproteína da Espícula de Coronavírus , Doenças dos Suínos , Vírus da Diarreia Epidêmica Suína/genética , Vírus da Diarreia Epidêmica Suína/classificação , Vírus da Diarreia Epidêmica Suína/isolamento & purificação , Animais , Suínos , China/epidemiologia , Doenças dos Suínos/virologia , Doenças dos Suínos/epidemiologia , Infecções por Coronavirus/virologia , Infecções por Coronavirus/veterinária , Infecções por Coronavirus/epidemiologia , Glicoproteína da Espícula de Coronavírus/genética , Variação Genética , Diarreia/virologia , Diarreia/veterinária , Diarreia/epidemiologia , Sequência de Aminoácidos , Substituição de Aminoácidos , GenótipoRESUMO
Phytochemical investigation into the medium polar fraction of the ethanol extract of Euphorbia peplus led to the identification of 32 diterpenoids with five structural types. Compounds 1-5 and 7-11 are reported for the first time, while the configuration of 6,7-epoxy group of 6 was revised to be ß-oriented. Compounds 1-5 feature a rare structural variation of the double bond at Δ1 migrating to Δ1(10) in the tigliane-type diterpenoid family. Biologically, compound 21 was found to be the only one to show moderate cytotoxic activity, associated with the presence of a benzoyloxy residue at C-16. Besides, compounds 4, 8, 12, 13, 16, and 19 show significant inhibitory activities against NO production induced by LPS in RAW264.7 macrophage cells, with IC50 values within 2-5 µM. Structure-activity relationship (SAR) analysis revealed that the ingenane-type diterpenoids have the best anti-inflammatory activity, and the esterification at 3-OH or 5-OH is crucial. Further biological researches demonstrated that 13, the predominant metabolite in this plant, exerts anti-inflammatory effects by blocking the activation of NF-κB and MAPK signaling pathways.
Assuntos
Antineoplásicos , Diterpenos , Euphorbia , Diterpenos/farmacologia , Diterpenos/química , Relação Estrutura-Atividade , Euphorbia/química , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/química , Antineoplásicos/farmacologia , Estrutura MolecularRESUMO
Diarrhea is a common issue in domestic yaks (Bos grunniens) that can occur with pasture alterations and significantly impacts growth performance. Previous research has examined the microbiota of diarrhetic yaks; however, the structural changes in gut bacterial community and microbial interactions in yaks with grassland alteration-induced diarrhea remain poorly understood. To explore variations in gut microbiota homeostasis among yaks suffering from diarrhea, fecal microbiota diversity and composition were analyzed using 16 S rRNA amplicon sequencing. Gut fecal microbiota diversity was lower in diarrhetic yaks than in non-diarrhetic yaks. Furthermore, the bacterial community composition (including that of Proteobacteria and Actinobacteria) in the feces of diarrhetic yaks displayed significant alterations. Co-occurrence network analysis further underscored the compromised intestinal flora stability in yaks with diarrhea relative to that in non-diarrhetic yaks. Interestingly, the abundance of beneficial bacteria, such as Lachnospiraceae_AC2044_group and Lachnospiraceae_NK4A136_group, were decreased in yaks with diarrhea, and the reductions were negatively correlated with the fecal water content. Collectively, these findings indicate that diminished microbial stability and increased abundance of certain bacteria in the gut may contribute to diarrhea occurrence in yaks.
Assuntos
Doenças dos Bovinos , Diarreia , Fezes , Microbioma Gastrointestinal , RNA Ribossômico 16S , Animais , Bovinos , Diarreia/veterinária , Diarreia/microbiologia , Fezes/microbiologia , Doenças dos Bovinos/microbiologia , RNA Ribossômico 16S/genética , Bactérias/classificação , Bactérias/isolamento & purificação , Bactérias/genéticaRESUMO
BACKGROUND: Social media has become an increasingly popular and critical tool for users to digest diverse information and express their perceptions and attitudes. While most studies endeavor to delineate the emotional responses of social media users, there is limited research exploring the factors associated with the emergence of emotions, particularly negative ones, during news consumption. OBJECTIVE: We aim to first depict the web coverage by news organizations on social media and then explore the crucial elements of news coverage that trigger the public's negative emotions. Our findings can act as a reference for responsible parties and news organizations in times of crisis. METHODS: We collected 23,705 Facebook posts with 1,019,317 comments from the public pages of representative news organizations in Hong Kong. We used text mining techniques, such as topic models and Bidirectional Encoder Representations from Transformers, to analyze news components and public reactions. Beyond descriptive analysis, we used regression models to shed light on how news coverage on social media is associated with the public's negative emotional responses. RESULTS: Our results suggest that occurrences of issues regarding pandemic situations, antipandemic measures, and supportive actions are likely to reduce the public's negative emotions, while comments on the posts mentioning the central government and the Government of Hong Kong reveal more negativeness. Negative and neutral media tones can alleviate the rage and interact with the subjects and issues in the news to affect users' negative emotions. Post length is found to have a curvilinear relationship with users' negative emotions. CONCLUSIONS: This study sheds light on the impacts of various components of news coverage (issues, subjects, media tone, and length) on social media on the public's negative emotions (anger, fear, and sadness). Our comprehensive analysis provides a reference framework for efficient crisis communication for similar pandemics at present or in the future. This research, although first extending the analysis between the components of news coverage and negative user emotions to the scenario of social media, echoes previous studies drawn from traditional media and its derivatives, such as web newspapers. Although the era of COVID-19 pandemic gradually brings down the curtain, the commonality of this research and previous studies also contributes to establishing a clearer territory in the field of health crises.
Assuntos
COVID-19 , Emoções , Mídias Sociais , Humanos , COVID-19/psicologia , COVID-19/epidemiologia , Hong Kong , Pandemias , Meios de Comunicação de Massa/estatística & dados numéricos , SARS-CoV-2 , Mineração de Dados/métodosRESUMO
AIMS: This study aims to outline the 'true' natural history of ascending thoracic aortic aneurysm (ATAA) based on a cohort of patients not undergoing surgical intervention. METHODS AND RESULTS: The outcomes, risk factors, and growth rates of 964 unoperated ATAA patients were investigated, over a median follow-up of 7.9 (maximum of 34) years. The primary endpoint was adverse aortic events (AAE), including dissection, rupture, and aortic death. At aortic sizes of 3.5-3.9, 4.0-4.4, 4.5-4.9, 5.0-5.4, 5.5-5.9, and ≥6.0 cm, the average yearly risk of AAE was 0.2%, 0.2%, 0.3%, 1.4%, 2.0%, and 3.5%, respectively (P < 0.001), and the 10-year survival free from AAE was 97.8%, 98.2%, 97.3%, 84.6%, 80.4%, and 70.9%, respectively (P < 0.001). The risk of AAE was relatively flat until 5 cm of aortic size, at which it began to increase rapidly (P for non-linearity <0.001). The mean annual growth rate was estimated to be 0.10 ± 0.01 cm/year. Ascending thoracic aortic aneurysms grew in a very slow manner, and aortic growth over 0.2 cm/year was rarely seen. Multivariable Cox regression identified aortic size [hazard ratio (HR): 1.78, 95% confidence interval (CI): 1.50-2.11, P < 0.001] and age (HR: 1.02, 95% CI: 1.00-1.05, P = 0.015) as significant independent risk factors for AAE. Interestingly, hyperlipidemia (HR: 0.46, 95% CI: 0.23-0.91, P = 0.025) was found to be a significant protective factor for AAE in univariable Cox regression. CONCLUSION: An aortic size of 5 cm, rather than 5.5 cm, may be a more appropriate intervention criterion for prophylactic ATAA repair. Aortic growth may not be an applicable indicator for intervention.
Assuntos
Aneurisma da Aorta Torácica , Aneurisma Aórtico , Dissecção Aórtica , Ruptura Aórtica , Humanos , Dissecção Aórtica/epidemiologia , Dissecção Aórtica/cirurgia , Universidades , Aneurisma Aórtico/cirurgia , Aorta , Aneurisma da Aorta Torácica/epidemiologia , Aneurisma da Aorta Torácica/cirurgia , Fatores de Risco , Estudos Retrospectivos , Ruptura Aórtica/cirurgiaRESUMO
Deferoxamine (DFO) is a water-soluble iron chelator used pharmacologically for the management of patients with transfusional iron overload. However, DFO is not cell-permeable and has a short plasma half-life, which necessitates lengthy parenteral administration with an infusion pump. We previously reported the synthesis of chitosan (CS) nanoparticles for sustained slow release of DFO. In the present study, we developed solid dispersions and nanoparticles of a carboxymethyl water-soluble chitosan derivative (CMCS) for improved DFO encapsulation and release. CS dispersions and nanoparticles with DFO have been prepared by ironical gelation using sodium triphosphate (TPP) and were examined for comparison purposes. The successful presence of DFO in CMCS polymeric dispersions and nanoparticles was confirmed through FTIR measurements. Furthermore, the formation of CMCS nanoparticles led to inclusion of DFO in an amorphous state, while dispersion of DFO in the polymeric matrix led to a decrease in its crystallinity according to X-ray diffraction (XRD) and differential scanning calorimetry (DSC) results. An in vitro release assay indicated sustained release of DFO from CS and CMCS nanoparticles over 48 h and 24 h, respectively. Application of CMCS-DFO dispersions to murine RAW 264.7 macrophages or human HeLa cervical carcinoma cells triggered cellular responses to iron deficiency. These were exemplified in the induction of the mRNA encoding transferrin receptor 1, the major iron uptake protein, and the suppression of ferritin, the iron storage protein. Our data indicate that CMCS-DFO nanoparticles release bioactive DFO that causes effective iron chelation in cultured cells.
Assuntos
Quitosana , Humanos , Animais , Camundongos , Desferroxamina/farmacologia , Quelantes , Transporte Biológico , FerroRESUMO
Mycobacteria, such as Mycobacterium tuberculosis, are characterized by a uniquely thick and waxy cell envelope that consists of two membranes, with a variety of mycolates comprising their outer membrane (OM). The protein Mycobacterial membrane protein Large 3 (MmpL3) is responsible for the transport of a primary OM component, trehalose monomycolate (TMM), from the inner (cytoplasmic) membrane (IM) to the periplasmic space, a process driven by the proton gradient. Although multiple structures of MmpL3 with bound substrates have been solved, the exact pathway(s) for TMM or proton transport remains elusive. Here, employing molecular dynamics simulations we investigate putative pathways for either transport species. We hypothesized that MmpL3 will cycle through similar conformational states as the related transporter AcrB, which we used as targets for modeling the conformation of MmpL3. A continuous water pathway through the transmembrane region was found in one of these states, illustrating a putative pathway for protons. Additional equilibrium simulations revealed that TMM can diffuse from the membrane into a binding pocket in MmpL3 spontaneously. We also found that acetylation of TMM, which is required for transport, makes it more stable within MmpL3's periplasmic cavity compared with the unacetylated form.
Assuntos
Proteínas de Membrana , Mycobacterium tuberculosis , Proteínas de Membrana/metabolismo , Prótons , Proteínas de Bactérias/química , Proteínas de Membrana Transportadoras/química , Proteínas de Transporte/metabolismo , Mycobacterium tuberculosis/metabolismo , Transporte BiológicoRESUMO
OBJECTIVE: Infective endocarditis (IE) caused by Staphylococcus species (spp.) is believed to be associated with higher morbidity and mortality rates. We hypothesize that Staphylococcus spp. are more virulent compared with other commonly causative bacteria of IE with regard to short-term and long-term mortality. BACKGROUND: It remains unclear if patients suffering from IE due to Staphylococcus spp. should be referred for surgical treatment earlier than other IE patients to avoid septic embolism and to optimize perioperative outcomes. MATERIALS AND METHODS: The database of the CAMPAIGN registry, comprising 4917 consecutive patients undergoing heart valve surgery, was retrospectively analyzed. Patients were divided into 2 groups with regard to the identified microorganisms: Staphylococcus group and the non- Staphylococcus group. The non- Staphylococcus group was subdivided for further analyses: Streptococcus group, Enterococcus group, and all other bacteria groups. RESULTS: The respective mortality rates at 30 days (18.7% vs 11.8%; P <0.001), 1 year (24.7% vs 17.7%; P <0.001), and 5 years (32.2% vs 24.5%; P <0.001) were significantly higher in Staphylococcus patients (n=1260) compared with the non- Staphylococcus group (n=1787). Multivariate regression identified left ventricular ejection fraction <30% ( P <0.001), chronic obstructive pulmonary disease ( P =0.045), renal insufficiency ( P =0.002), Staphylococcus spp. ( P =0.032), and Streptococcus spp. ( P =0.013) as independent risk factors for 30-day mortality. Independent risk factors for 1-year mortality were identified as: age ( P <0.001), female sex ( P =0.018), diabetes ( P =0.018), preoperative stroke ( P =0.039), chronic obstructive pulmonary disease ( P =0.001), preoperative dialysis ( P <0.001), and valve vegetations ( P =0.004). CONCLUSIONS: Staphylococcus endocarditis is associated with an almost twice as high 30-day mortality and significantly inferior long-term outcome compared with IE by other commonly causative bacteria. Patients with Staphylococcus infection are more often female and critically ill, with >50% of these patients suffering from clinically relevant septic embolism. Early diagnosis and referral to a specialized center for surgical treatment are strongly recommended to reduce the incidence of preoperative deterioration and stroke due to septic embolism.
Assuntos
Embolia , Endocardite Bacteriana , Endocardite , Doença Pulmonar Obstrutiva Crônica , Infecções Estafilocócicas , Acidente Vascular Cerebral , Feminino , Humanos , Bactérias , Embolia/complicações , Endocardite/complicações , Endocardite/diagnóstico , Endocardite/microbiologia , Endocardite Bacteriana/cirurgia , Endocardite Bacteriana/diagnóstico , Endocardite Bacteriana/microbiologia , Mortalidade Hospitalar , Doença Pulmonar Obstrutiva Crônica/complicações , Estudos Retrospectivos , Fatores de Risco , Infecções Estafilocócicas/microbiologia , Staphylococcus , Volume Sistólico , Função Ventricular Esquerda , Virulência , MasculinoRESUMO
The tobacco-specific nitrosamine N'-nitrosonornicotine (NNN) and its close analogue 4-(N-nitrosomethylamino)-1-(3-pyridyl)-1-butanone (NNK) are classified as "carcinogenic to humans" (Group 1) by the International Agency for Research on Cancer. The currently used biomarker to monitor NNN exposure is urinary total NNN (free NNN plus its N-glucuronide). However, total NNN does not provide information about the extent of metabolic activation of NNN as related to its carcinogenicity. Targeted analysis of the major metabolites of NNN in laboratory animals recently led to the identification of N'-nitrosonornicotine-1N-oxide (NNN-N-oxide), a unique metabolite detected in human urine that is specifically formed from NNN. To further investigate NNN urinary metabolites that hold promise as new biomarkers for monitoring NNN exposure, uptake, and/or metabolic activation, we conducted a comprehensive profiling of NNN metabolites in the urine of F344 rats treated with NNN or [pyridine-d4]NNN. Using our optimized high-resolution mass spectrometry (HRMS)-based isotope-labeling method, 46 putative metabolites were identified with robust MS evidence. Out of the 46 candidates, all known major NNN metabolites were identified and structurally confirmed by comparing them to their isotopically labeled standards. More importantly, putative metabolites considered to be exclusively formed from NNN were also identified. The two new representative metabolitesâ4-(methylthio)-4-(pyridin-3-yl)butanoic acid (23, MPBA) and N-acetyl-S-(5-(pyridin-3-yl)-1H-pyrrol-2-yl)-l-cysteine (24, Py-Pyrrole-Cys-NHAc) âwere identified by comparing them to synthetic standards that were fully characterized by nuclear magnetic resonance and HRMS. They are hypothesized to be formed by NNN α-hydroxylation pathways and thus represent the first potential biomarkers to specifically monitor the uptake plus metabolic activation of NNN in tobacco users.
Assuntos
Nitrosaminas , Ratos , Humanos , Animais , Ratos Endogâmicos F344 , Nitrosaminas/química , Carcinógenos/metabolismo , Espectrometria de Massas , ÓxidosRESUMO
BACKGROUND: Pancreatic adenocarcinoma (PAAD) is a malignant tumor with a high mortality rate. Methylation modifications acted a crucial role to affect cancer progression. The current study aimed to explore the potential role of methylase regulators in PAAD prognosis and immune microenvironment. METHODS: PubMed and TCGA databases were used to systematically analyze methylase regulators in PAAD. We identified three methylase clusters based on RNA methylase transcriptome data and obtained three gene clusters based on methylase modification-related differently expressed genes using principal component analysis (PCA) analysis. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis and Gene Ontology (GO) biological processes were performed to explore the processes enriched in the different subgroups and single sample gene-set enrichment analysis (ssGSEA) was used to analyze the relationship between subgroups and immune infiltration in PAAD. RESULTS: We systematically screened 43 methylase regulators in PAAD samples and identified three methylase clusters with different clinical outcomes, as well as detected a significant relationship between methylase clusters and tumor immune infiltration. The top ten mutated genes include TP53, Kirsten rat sarcoma viral oncogene homolog (KRAS), titin gene (TTN), mucin 16 (MUC16), SMAD4, cyclin-dependent kinase inhibitor 2a (CDKN2A), Ryanodine receptor isoform-1 (RYR1), ring finger 43 (RNF43), protocadherin-15 (PCDH15), and AT-rich interacting domain-containing protein 1 A gene (ARID1A). CONCLUSION: The current study constructed an m6A/m5C/m1A/m7G modulator genes and explored methylase modification-related genes, which were related to the prognosis of PAAD patients and the immune checkpoint point cytotoxic T-lymphocyte associated protein 4 (CTLA4). These findings may provide prognostic predictors and direction for immunotherapy strategies for the treatment of PAAD.
Assuntos
Adenocarcinoma , Neoplasias Pancreáticas , Humanos , Família Multigênica , Metiltransferases , Regulação Neoplásica da Expressão Gênica , Microambiente Tumoral , Neoplasias PancreáticasRESUMO
Seven rarely spirooxindole alkaloids, voagafricines A-G (1-7) were isolated from the stem barks of Voacanga africana. Their structures were unambiguously elucidated by comprehensive spectroscopic data and electronic circular dichroism (ECD) analyses. 1 and 2 possess a unique indoleone system in conjugation with a 3,4'-decahydroquinoline spiral ring originating from seco-quinolhiddin core of the precursor, furthermore 1 undergo decarburization formed a novel C-3-nor monoterpenoid indole. All isolates were evaluated for their antibacterial activities against MBLs producing Escherichia coli strains. Compounds 1 and 7 were found to be potent inhibitors against E. coli 298 and 140 by targeting biofilm. Possible interaction sites of 1 and 7 with biofilm were preliminarily explored by means of molecular docking.
Assuntos
Alcaloides , Voacanga , Voacanga/química , Escherichia coli , Simulação de Acoplamento Molecular , Alcaloides/farmacologia , Estrutura MolecularRESUMO
Glyphosate is a widely used herbicide that has deleterious effects on animal reproduction. However, details regarding the systematic mechanisms of glyphosate-induced reproductive toxicity are limited. This study aimed to investigate the toxic effects of glyphosate-based herbicide (GBH) on reproduction in mice exposed to 0 (control group), 50 (low-dose group), 250 (middle-dose group), and 500 (high-dose group) mg/kg/day GBH for 30 days. Toxicological parameters, metabolomics, and transcriptomics were performed to reveal GBH-induced reproductive toxicity. Our findings demonstrated that GBH exposure damaged mitochondrial pyknosis and the nuclear membrane of spermatogonia. GBH triggered a significant increase in sperm malformations in the high-dose group. Omics data showed that GBH impaired the Krebs cycle and respiratory chain, blocked pyruvate metabolism and glycolysis/gluconeogenesis, and influenced the pentose phosphate pathway and nucleotide synthesis and metabolism. Overall, the multi-omics results revealed systematic and comprehensive evidence of the adverse effects of GBH exposure, providing new insights into the reproductive toxicity of organophosphorus pesticides.
Assuntos
Herbicidas , Praguicidas , Animais , Masculino , Camundongos , Testículo , Herbicidas/toxicidade , Transcriptoma , Compostos Organofosforados , Sêmen , Reprodução , Metabolômica , Nucleotídeos , GlifosatoRESUMO
PURPOSE: We developed and tested a novel method of creating intensity modulated proton arc therapy (IMPAT) plans that uses computing resources similar to those for regular intensity-modulated proton therapy (IMPT) plans and may offer a dosimetric benefit for patients with ependymoma or similar tumor geometries. METHODS: Our IMPAT planning method consists of a geometry-based energy selection step with major scanning spot contributions as inputs computed using ray-tracing and single-Gaussian approximation of lateral spot profiles. Based on the geometric relation of scanning spots and dose voxels, our energy selection module selects a minimum set of energy layers at each gantry angle such that each target voxel is covered by sufficient scanning spots as specified by the planner, with dose contributions above the specified threshold. Finally, IMPAT plans are generated by robustly optimizing scanning spots of the selected energy layers using a commercial proton treatment planning system (TPS). The IMPAT plan quality was assessed for four ependymoma patients. Reference three-field IMPT plans were created with similar planning objective functions and compared with the IMPAT plans. RESULTS: In all plans, the prescribed dose covered 95% of the clinical target volume (CTV) while maintaining similar maximum doses for the brainstem. While IMPAT and IMPT achieved comparable plan robustness, the IMPAT plans achieved better homogeneity and conformity than the IMPT plans. The IMPAT plans also exhibited higher relative biological effectiveness (RBE) enhancement than did the corresponding reference IMPT plans for the CTV in all four patients and brainstem in three of them. CONCLUSIONS: The proposed method demonstrated potential as an efficient technique for IMPAT planning and may offer a dosimetric benefit for patients with ependymoma or tumors in close proximity to critical organs. IMPAT plans created using this method had elevated RBE enhancement associated with increased linear energy transfer (LET) in both targets and abutting critical organs.
Assuntos
Ependimoma , Terapia com Prótons , Radioterapia de Intensidade Modulada , Humanos , Terapia com Prótons/métodos , Prótons , Dosagem Radioterapêutica , Ependimoma/radioterapia , Radioterapia de Intensidade Modulada/métodos , Planejamento da Radioterapia Assistida por Computador/métodos , Órgãos em RiscoRESUMO
The survival, growth, and virulence of Leishmania spp., a group of protozoan parasites, depends on the proper access and regulation of iron. Macrophages, Leishmania's host cell, may divert iron traffic by reducing uptake or by increasing the efflux of iron via the exporter ferroportin. This parasite has adapted by inhibiting the synthesis and inducing the degradation of ferroportin. To study the role of iron in leishmaniasis, we employed Hjv-/- mice, a model of hemochromatosis. The disruption of hemojuvelin (Hjv) abrogates the expression of the iron hormone hepcidin. This allows unrestricted iron entry into the plasma from ferroportin-expressing intestinal epithelial cells and tissue macrophages, resulting in systemic iron overload. Mice were injected with Leishmania major in hind footpads or intraperitoneally. Compared with wild-type controls, Hjv-/- mice displayed transient delayed growth of L. major in hind footpads, with a significant difference in parasite burden 4 weeks post-infection. Following acute intraperitoneal exposure to L. major, Hjv-/- peritoneal cells manifested increased expression of inflammatory cytokines and chemokines (Il1b, Tnfa, Cxcl2, and Ccl2). In response to infection with L. infantum, the causative agent of visceral leishmaniasis, Hjv-/- and control mice developed similar liver and splenic parasite burden despite vastly different tissue iron content and ferroportin expression. Thus, genetic iron overload due to hemojuvelin deficiency appears to mitigate the early development of only cutaneous leishmaniasis.