RESUMO
As methicillin-resistant Staphylococcus aureus (MRSA) exhibits formidable resistance to many drugs, the imperative for alternative therapeutic strategies becomes increasingly evident. At the heart of our study is the identification of a novel inhibitor through fluorescence anisotropy assays, specifically targeting the crucial multiple gene regulator A (MgrA) regulatory network in S. aureus. Isorhapontigenin (Iso), a natural compound, exhibits outstanding inhibitory efficacy, modulating bacterial virulence pathways without exerting direct bactericidal activity. This suggests a paradigm shift toward attenuating virulence instead of purely focusing on bacterial elimination. Through comprehensive in vitro and in vivo evaluations, we elucidated the complex interplay between Iso and MgrA, leading to reduced S. aureus adhesion, and overall virulence. At the cellular level, Iso offers significant protection to A549 cells infected with S. aureus, reducing cellular damage. Importantly, Iso augments the chemotaxis of neutrophils, curtailing the immune evasion capabilities of S. aureus. Furthermore, in vivo investigations highlight the notable effectiveness of Iso against MRSA-induced pneumonia and within the Galleria mellonella infection model, underscoring its pivotal role in the evolving realm of antibacterial drug discovery. Significantly, when Iso is used in combination with vancomycin, it outperforms its solo application, indicating a more pronounced therapeutic impact. This seminal research emphasizes Iso's potential as a primary defense against the surge of multidrug-resistant pathogens, heralding new prospects in antimicrobial therapy.
Assuntos
Antibacterianos , Staphylococcus aureus Resistente à Meticilina , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Antibacterianos/farmacologia , Antibacterianos/uso terapêutico , Animais , Humanos , Virulência/efeitos dos fármacos , Células A549 , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Mariposas/microbiologia , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Testes de Sensibilidade Microbiana , Redes Reguladoras de Genes/efeitos dos fármacos , Camundongos , Neutrófilos/efeitos dos fármacosRESUMO
In the fight against hospital-acquired infections, the challenge posed by methicillin-resistant Staphylococcus aureus (MRSA) necessitates the development of novel treatment methods. This study focused on undermining the virulence of S. aureus, especially by targeting surface proteins crucial for bacterial adherence and evasion of the immune system. A primary aspect of our approach involves inhibiting sortase A (SrtA), a vital enzyme for attaching microbial surface components recognizing adhesive matrix molecules (MSCRAMMs) to the bacterial cell wall, thereby reducing the pathogenicity of S. aureus. Verbascoside, a phenylethanoid glycoside, was found to be an effective SrtA inhibitor in our research. Advanced fluorescence quenching and molecular docking studies revealed a specific interaction between verbascoside and SrtA, pinpointing the critical active sites involved in this interaction. This molecular interaction significantly impedes the SrtA-mediated attachment of MSCRAMMs, resulting in a substantial reduction in bacterial adhesion, invasion, and biofilm formation. The effectiveness of verbascoside has also been demonstrated in vivo, as shown by its considerable protective effects on pneumonia and Galleria mellonella (wax moth) infection models. These findings underscore the potential of verbascoside as a promising component in new antivirulence therapies for S. aureus infections. By targeting crucial virulence factors such as SrtA, agents such as verbascoside constitute a strategic and potent approach for tackling antibiotic resistance worldwide. KEY POINTS: ⢠Verbascoside inhibits SrtA, reducing S. aureus adhesion and biofilm formation. ⢠In vivo studies demonstrated the efficacy of verbascoside against S. aureus infections. ⢠Targeting virulence factors such as SrtA offers new avenues against antibiotic resistance.
Assuntos
Aminoaciltransferases , Antibacterianos , Aderência Bacteriana , Proteínas de Bactérias , Biofilmes , Cisteína Endopeptidases , Glucosídeos , Staphylococcus aureus Resistente à Meticilina , Simulação de Acoplamento Molecular , Fenóis , Infecções Estafilocócicas , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/antagonistas & inibidores , Aminoaciltransferases/antagonistas & inibidores , Aminoaciltransferases/metabolismo , Cisteína Endopeptidases/metabolismo , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Glucosídeos/farmacologia , Animais , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Fenóis/farmacologia , Aderência Bacteriana/efeitos dos fármacos , Biofilmes/efeitos dos fármacos , Antibacterianos/farmacologia , Mariposas/microbiologia , Virulência/efeitos dos fármacos , Modelos Animais de Doenças , Fatores de Virulência/metabolismo , Inibidores Enzimáticos/farmacologia , PolifenóisRESUMO
Pancreatic cancer, predominantly pancreatic ductal adenocarcinoma (PDAC), remains a highly lethal malignancy with limited therapeutic options and a dismal prognosis. By targeting the underlying molecular abnormalities responsible for PDAC development and progression, gene therapy offers a promising strategy to overcome the challenges posed by conventional radiotherapy and chemotherapy. This study sought to explore the therapeutic potential of small activating RNAs (saRNAs) specifically targeting the CCAAT/enhancer-binding protein alpha (CEBPA) gene in PDAC. To overcome the challenges associated with saRNA delivery, tetrahedral framework nucleic acids (tFNAs) were rationally engineered as nanocarriers. These tFNAs were further functionalized with a truncated transferrin receptor aptamer (tTR14) to enhance targeting specificity for PDAC cells. The constructed tFNA-based saRNA formulation demonstrated exceptional stability, efficient saRNA release ability, substantial cellular uptake, biocompatibility, and nontoxicity. In vitro experiments revealed successful intracellular delivery of CEBPA-saRNA utilizing tTR14-decorated tFNA nanocarriers, resulting in significant activation of tumor suppressor genes, namely, CEBPA and its downstream effector P21, leading to notable inhibition of PDAC cell proliferation. Moreover, in a mouse model of PDAC, the tTR14-decorated tFNA-mediated delivery of CEBPA-saRNA effectively upregulated the expression of the CEBPA and P21 genes, consequently suppressing tumor growth. These compelling findings highlight the potential utility of saRNA delivered via a designed tFNA nanocarrier to induce the activation of tumor suppressor genes as an innovative therapeutic approach for PDAC.
Assuntos
Aptâmeros de Nucleotídeos , Carcinoma Ductal Pancreático , Neoplasias Pancreáticas , Receptores da Transferrina , Animais , Humanos , Neoplasias Pancreáticas/tratamento farmacológico , Carcinoma Ductal Pancreático/tratamento farmacológico , Aptâmeros de Nucleotídeos/química , Aptâmeros de Nucleotídeos/farmacologia , Receptores da Transferrina/metabolismo , Camundongos , Linhagem Celular Tumoral , Proteínas Estimuladoras de Ligação a CCAAT/metabolismo , Proteínas Estimuladoras de Ligação a CCAAT/genética , Proliferação de Células/efeitos dos fármacos , Terapia Genética/métodos , RNA Interferente Pequeno/farmacologia , Camundongos NusRESUMO
BACKGROUND: China's transition into an aging society is accelerated by the simultaneous decline in fertility rates and the prolonged life expectancy of older adults. The impact of widowhood, a significant stressor in old age, has emerged as a crucial factor affecting the quality of life among the elderly. METHODS: This study is based on data from the 2018 China Health and Aging Tracking Survey. Multiple linear regression models were employed to investigate the influence of widowhood on the quality of life of older adults in China. Additionally, Bootstrap mediation effects were utilized to assess the mediating role of intergenerational support, considering both financial and emotional support from children. RESULTS: The findings indicate a substantial reduction in the quality of life index among older adults following widowhood. Moreover, the impact is more pronounced among older men compared to older women. Rural older adults experience a significant decline in quality of life post-widowhood, while the effect on urban counterparts is not statistically significant. CONCLUSIONS: Intergenerational financial support was identified as a partial mediator between widowhood and the quality of life among older adults. This underscores the importance of familial financial assistance in mitigating the adverse effects of widowhood on the well-being of the elderly. These results offer valuable insights into the nuanced impact of widowhood on the quality of life among older adults in China, emphasizing the need for targeted interventions, especially in rural areas. CLINICAL TRIAL: Not applicable.
Assuntos
Relação entre Gerações , Qualidade de Vida , Viuvez , Humanos , Qualidade de Vida/psicologia , Masculino , Feminino , Viuvez/psicologia , Idoso , China/epidemiologia , Idoso de 80 Anos ou mais , Apoio Social , Pessoa de Meia-IdadeRESUMO
BACKGROUND: Little is understood about the association between psychosomatic symptoms and advanced cancer among older Chinese patients. METHODS: This secondary analysis was part of a multicenter cross-sectional study based on an electronic patient-reported outcome platform. Patients with advanced cancer were included between August 2019 and December 2020 in China. Participants (over 60 years) completed the MD Anderson Symptom Inventory (MDASI) and Hospital Anxiety and Depression Scale (HADS) to measure symptom burden. Network analysis was also conducted to investigate the network structure, centrality indices (strength, closeness, and betweenness) and network stability. RESULTS: A total of 1022 patients with a mean age of 66 (60-88) years were included; 727 (71.1%) were males, and 295 (28.9%) were females. A total of 64.9% of older patients with advanced cancer had one or more symptoms, and up to 80% had anxiety and depression. The generated network indicated that the physical symptoms, anxiety and depression symptom communities were well connected with each other. Based on an evaluation of the centrality indices, 'distress/feeling upset' (MDASI 5) appears to be a structurally important node in all three networks, and 'I lost interest in my own appearance' (HADS-D4) had the lowest centrality indices. The network stability was relatively high (> 0.7). CONCLUSION: The symptom burden remains high in older patients with advanced cancer in China. Psychosomatic symptoms are highly interactive and often present as comorbidities. This network can be used to provide targeted interventions to optimize symptom management in older patients with advanced cancer in China. TRIAL REGISTRATION: Chinese Clinical Trial Registry (ChiCTR1900024957), registered on 06/12/2020.
Assuntos
Depressão , Neoplasias , Masculino , Feminino , Humanos , Idoso , Depressão/diagnóstico , Depressão/epidemiologia , Estudos Transversais , Ansiedade/diagnóstico , Ansiedade/epidemiologia , Neoplasias/complicações , Neoplasias/diagnóstico , Neoplasias/epidemiologia , Transtornos de AnsiedadeRESUMO
The increasing prevalence of infections related to methicillin-resistant Staphylococcus aureus (MRSA) necessitates the exploration of innovative therapeutic strategies that diverge from conventional antibiotic treatments. This is imperative to effectively combat resistance and manage these infections. The adoption of antivirulence strategies has emerged as a particularly promising avenue. This approach applies a heightened selective pressure on pathogens, thereby diminishing the likelihood of bacteria evolving resistance to antibiotics. In our pursuit of novel therapeutics for treating MRSA infections, we have focused on agents that inhibit the virulence of S. aureus without impeding its growth, aiming to minimize the development of drug resistance. α-Hemolysin, a critical virulence factor encoded by the hla gene, is a cytotoxin that forms pores in host cell membranes and plays a pivotal role in the progression of disease during bacterial infections. Herein, we identified that norwogonin could effectively inhibit Hla production via targeting agrAC, a crucial protein in quorum sensing, resulting in dose-dependent inhibition of hemolytic activity without suppressing S. aureus growth. In vitro assays illustrated that norwogonin decreased the thermal stability of agrAC, providing evidence of interaction between norwogonin and agrAC. Meanwhile, norwogonin alleviated Hla-mediated A549 cell damage and reduced lactate dehydrogenase release. In vivo studies suggested that norwogonin treatment blocked the establishment of a mouse model of pneumonia caused by S. aureus USA300. Notably, norwogonin enhanced the antibacterial potency of oxacillin. In conclusion, norwogonin is a promising candidate for treating S. aureus infections, offering a novel alternative to traditional antibiotics by targeting virulence factors and enhancing the efficacy of existing treatments.
Assuntos
Antibacterianos , Proteínas de Bactérias , Proteínas Hemolisinas , Staphylococcus aureus Resistente à Meticilina , Fatores de Virulência , Animais , Feminino , Humanos , Camundongos , Células A549 , Antibacterianos/farmacologia , Proteínas de Bactérias/metabolismo , Proteínas de Bactérias/genética , Toxinas Bacterianas/metabolismo , Modelos Animais de Doenças , Proteínas Hemolisinas/metabolismo , Hemólise/efeitos dos fármacos , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Camundongos Endogâmicos BALB C , Percepção de Quorum/efeitos dos fármacos , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Virulência/efeitos dos fármacos , Fatores de Virulência/metabolismoRESUMO
Methicillin-resistant Staphylococcus aureus (MRSA) is a pathogenic bacterium responsible for a range of severe infections, such as skin infections, bacteremia, and pneumonia. Due to its antibiotic-resistant nature, current research focuses on targeting its virulence factors. Sortase A (SrtA) is a transpeptidase that anchors surface proteins to the bacterial cell wall and is involved in adhesion and invasion to host cells. Through fluorescence resonance energy transfer (FRET), we identified echinacoside (ECH), a natural polyphenol, as a potential SrtA inhibitor with an IC50 of 38.42 µM in vitro. It was demonstrated that ECH inhibited SrtA-mediated S. aureus fibrinogen binding, surface protein A anchoring, and biofilm formation. The fluorescence quenching assay determined the binding mode of ECH to SrtA and calculated the KA-binding constant of 3.09 × 105 L/mol, demonstrating the direct interaction between the two molecules. Molecular dynamics simulations revealed that ECH-SrtA interactions occurred primarily at the binding sites of A92G, A104G, V168A, G192A, and R197A. Importantly, the combination of ECH and vancomycin offered protection against murine models of MRSA-induced pneumonia. Therefore, ECH may serve as a potential antivirulence agent against S. aureus infections, either alone or in combination with vancomycin.
Assuntos
Staphylococcus aureus Resistente à Meticilina , Pneumonia , Animais , Camundongos , Humanos , Staphylococcus aureus Resistente à Meticilina/metabolismo , Vancomicina/farmacologia , Vancomicina/uso terapêutico , Staphylococcus aureus/metabolismo , Modelos Animais de Doenças , Proteínas de Bactérias/metabolismoRESUMO
AIMS: Disabling bacterial virulence with small molecules has been proposed as a potential strategy to prevent bacterial pathogenicity. The von Willebrand factor-binding protein of Staphylococcus aureus was identified previously as a key virulence determinant. Our objective was to discover a von Willebrand-factor binding protein (vWbp) inhibitor distinct from the antibiotics used to prevent infections resulting from S. aureus. METHODS AND RESULTS: Using coagulation assays, we found that the sesquiterpene trilactone bilobalide blocks coagulation mediated by vWbp, but has no impact on the growth of S. aureus at a concentration of 128 µg ml-1. Moreover, a mouse model of pneumonia caused by S. aureus indicated that bilobalide could attenuate S. aureus virulence in vivo. This effect is achieved not by interfering with the expression of vWbp but by binding to vWbp, as demonstrated by western blotting, thermal shift assays, and fluorescence quenching assays. Using molecular dynamic simulations and point mutagenesis analysis, we identified that the Q17A and R453A residues are key residues for the binding of bilobalide to vWbp. CONCLUSIONS: Overall, we tested the ability of bilobalide to inhibit S. aureus infections by targeting vWbp and explored the potential mechanism of this activity.
Assuntos
Bilobalídeos , Pneumonia , Infecções Estafilocócicas , Camundongos , Animais , Proteínas de Transporte/metabolismo , Fator de von Willebrand/genética , Fator de von Willebrand/metabolismo , Staphylococcus aureus/metabolismo , Infecções Estafilocócicas/tratamento farmacológicoRESUMO
Drug-resistant bacteria was the third leading cause of death worldwide in 2019, which sounds like a cautionary note for global public health. Therefore, developing novel strategies to combat Methicillin-resistant Staphylococcus aureus (MRSA) infections is the need of the hour. Caseinolytic protease P (ClpP) represents pivotal microbial degradation machinery in MRSA involved in bacterial homeostasis and pathogenicity, considered an ideal target for combating S. aureus infections. Herein, we identified a natural compound, hinokiflavone, that inhibited the activity of ClpP of MRSA strain USA300 with an IC50 of 34.36 µg/mL. Further assays showed that hinokiflavone reduced the virulence of S. aureus by inhibiting multiple virulence factors expression. Results obtained from cellular thermal transfer assay (CETSA), thermal shift assay (TSA), local surface plasmon resonance (LSPR) and molecular docking (MD) assay enunciated that hinokiflavone directly bonded to ClpP with confirmed docking sites, including SER-22, LYS-26 and ARG-28. In vivo, the evaluation of anti-infective activity showed that hinokiflavone in combination with vancomycin effectively protected mice from MRSA-induced fatal pneumonia, which was more potent than vancomycin alone. As mentioned above, hinokiflavone, as an inhibitor of ClpP, could be further developed into a promising adjuvant against S. aureus infections.
Assuntos
Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Animais , Antibacterianos/farmacologia , Biflavonoides , Camundongos , Simulação de Acoplamento Molecular , Peptídeo Hidrolases/farmacologia , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus , Vancomicina/farmacologia , VirulênciaRESUMO
Staphylococcus aureus (S. aureus) is a common pathogenic bacterium that induces a variety of diseases in humans and animals. The significant pathogenicity of S. aureus is due to its expression of several virulence factors. Alpha-hemolysin (Hla) has attracted attention as a virulence factor in staphylococcal pathogenesis and has been the predominant focus of intense research. In this study, we found that kaempferol, a flavonoid compound, inhibited hemolysis at a low concentration (32 µg/mL) and exerted no effect on bacterial growth. Western blot and RT-qPCR assays further demonstrated that kaempferol downregulated the expression of Hla in S. aureus. We observed that kaempferol alleviated the damage from S. aureus Hla in A549 cells. More importantly, kaempferol showed a potent protective effect on mice pneumonia induced by MRSA, as evidenced by a significant improvement in the survival of mice, a reduction in the number of colonized colonies in lung tissue and a decrease in the pathological damage to lung tissues. In summary, the results demonstrate the protective effect of kaempferol on MRSA-induced lethal pneumonia in mice and indicate that kaempferol could be developed as a potential anti-MRSA drug.
Assuntos
Toxinas Bacterianas , Staphylococcus aureus Resistente à Meticilina , Pneumonia Estafilocócica , Animais , Antibacterianos , Proteínas Hemolisinas , Quempferóis/farmacologia , Camundongos , Pneumonia Estafilocócica/tratamento farmacológico , Staphylococcus aureusRESUMO
INTRODUCTION: Major depressive disorder (MDD) is associated with an increased risk of suicide and suicide attempt among cancer patients. However, we do not know how many cancer patients without MDD have suicidal ideation (SI). OBJECTIVES: This study aimed to investigate the prevalence, characteristics and correlated factors of SI among advanced cancer patients without MDD. METHODS: This is a multi-center, cross-sectional study based on an electronic patient-reported outcome systems in patients who were diagnosed with advanced lung, liver, gastric, esophageal, colorectal or breast cancer, the top six prevalent cancers in China. A total of 2930 advanced cancer patients were recruited from 10 regional representative cancer centers across China from August 2019 to December 2020. Patients completed the Patient Health Questionnaire-9 regarding if they had thoughts of being better off dead or of hurting themselves in some way in the previous 2 weeks. Patients also completed the symptom inventory and quality of life assessment. Generalized estimating equation model was performed to explore the correlated factors associated with SI among the patients without MDD. RESULTS: The overall prevalence of SI among advanced cancer patients without MDD was 13.1%. The prevalence was higher in older patients. After adjusted for existing conditions, patients with vomiting symptom (p < 0.001), poorer life quality (p < 0.001), and middle education level (p = 0.031) were correlated factors of SI. CONCLUSIONS: The suicidal ideation is common in advanced cancer patients without MDD. Patients with vomiting, poor quality of life, and middle education level should be screened and monitored for suicidal ideation even without MDD. CLINICAL TRIAL INFORMATION: ChiCTR1900024957.
Assuntos
Transtorno Depressivo Maior , Neoplasias , Humanos , Idoso , Ideação Suicida , Transtorno Depressivo Maior/epidemiologia , Transtorno Depressivo Maior/diagnóstico , Estudos Transversais , Qualidade de Vida , Vômito , Neoplasias/epidemiologiaRESUMO
Non-small cell lung cancer (NSCLC) poses a serious threat to public health due to its significant morbidity and mortality rates. The processes of NSCLC formation and development are quite complex and involve numerous regulatory biomolecules. Long non-coding RNAs (lncRNAs) have attracted attention since they have been found to play critical roles in the tumorigenesis of various human malignancies. Recently, double homeobox A pseudogene 8 (DUXAP8) was identified as an oncogenic lncRNA that is overexpressed in different tumor types. In NSCLC, high expression of DUXAP8 is associated with poor prognosis in patients. The regulatory mechanism underlying the oncogenic effects of DUXAP8 can be divided into transcriptional level and post-transcriptional level. DUXAP8 promotes proliferation, epithelial-mesenchymal transition, and aerobic glycolysis in NSCLC cells. Moreover, DUXAP8 shows potential for the diagnosis and treatment of NSCLC. Herein, we review the molecular mechanisms underlying the DUXAP8-mediated phenotypes of NSCLC as well as its potential clinical applications.
Assuntos
Carcinoma Pulmonar de Células não Pequenas , Neoplasias Pulmonares , MicroRNAs , RNA Longo não Codificante , Carcinoma Pulmonar de Células não Pequenas/genética , Linhagem Celular Tumoral , Proliferação de Células/genética , Regulação Neoplásica da Expressão Gênica/genética , Genes Homeobox , Humanos , Neoplasias Pulmonares/genética , Neoplasias Pulmonares/patologia , MicroRNAs/genética , Pseudogenes , RNA Longo não Codificante/genética , RNA Longo não Codificante/metabolismoRESUMO
Staphylococcus aureus, especially drug-resistant S. aureus infections, is a worldwide healthcare challenge. There is a growing focus on antivirulence therapy against S. aureus. Caseinolytic protease p (ClpP) is a protein hydrolase essential for pathogenicity in S. aureus. A flavonoid compound, tamarixetin, which was screened in this work, was specifically able to inhibit the hydrolytic activity of ClpP on the fluorescent substrate Suc-LY-AMC with an IC50 of 49.73 µM, without affecting the growth of methicillin-resistant S. aureus strain USA300 and was without obvious cytotoxicity. Further assays found that tamarixetin inhibited the transcription of hla, agr, RNAIII, pvl, PSM-α, and spa genes as well as suppressed the protein expression levels of Hla and PVL. Moreover, tamarixetin was observed to dramatically inhibit the hemolytic activity of hla in S. aureus. Consistent with that of S. aureus USA300-ΔclpP, tamarixetin was shown to increase urease expression. The thermal shift and cellular thermal shift assays showed that tamarixetin markedly changed the thermal stability of ClpP. The dissociation constant (KD) value of tamarixetin with ClpP was 2.52 × 10-6 M measured by surface plasmon resonance. The molecular docking and ClpP point mutation results also demonstrated that tamarixetin had a strong interaction with ClpP. In vivo study showed that tamarixetin was effective in protecting mice from S. aureus pneumonia by increasing survival, reducing lung tissue load, and slowing down the infiltration of inflammatory factors. In addition, tamarixetin was able to enhance the antibacterial activity of cefotaxime in combination. In conclusion, tamarixetin was promising as a ClpP inhibitor for S. aureus infections.
Assuntos
Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Animais , Proteínas de Bactérias/genética , Dissacarídeos , Camundongos , Simulação de Acoplamento Molecular , Peptídeo Hidrolases , Quercetina/análogos & derivados , Staphylococcus aureus , Virulência , Fatores de Virulência/genéticaRESUMO
Methicillin-resistant Staphylococcus aureus (MRSA) is a zoonotic antibiotic-resistant pathogen that negatively impacts society from medical, veterinary, and societal standpoints. The search for alternative therapeutic strategies and innovative anti-infective agents is urgently needed. Among the pathogenic mechanisms of Staphylococcus aureus (S. aureus), sortase A is a virulence factor of great concern because it is highly linked with the ability of MRSA to invade the host. In this study, we identified that rhodionin, a natural compound of flavonoid glucosides, effectively inhibited the activity of SrtA without affecting the survival and growth of bacteria, and its half maximal inhibitory concentration (IC50) value was 22.85 µg/mL. In vitro, rhodionin prominently attenuated the virulence-related phenotype of SrtA by reducing the adhesion of S. aureus to fibrinogen, reducing the capacity of protein A (SpA) on the bacterial surface and biofilm formation. Subsequently, fluorescence quenching and molecular docking were performed to verify that rhodionin directly bonded to SrtA molecule with KA value of 6.22 × 105 L/mol. More importantly, rhodionin showed a significant protective effect on mice pneumonia model and improved the survival rate of mice. According to the above findings, rhodionin achieved efficacy in the treatment of MRSA-induced infections, which holds promising potential to be developed into a candidate used for MRSA-related infections.
Assuntos
Staphylococcus aureus Resistente à Meticilina , Pneumonia Estafilocócica , Camundongos , Animais , Staphylococcus aureus , Simulação de Acoplamento Molecular , Flavonoides/farmacologiaRESUMO
Staphylococcus aureus (S. aureus), a Gram-positive bacteria, is an incurable cause of hospital and community-acquired infections. Inhibition bacterial virulence is a viable strategy against S. aureus infections based on the multiple virulence factors secreted by S. aureus. Alpha-hemolysin (Hla) plays a crucial role in bacteria virulence without affecting bacterial viability. Here, we identified that 7,8-Dihydroxyflavone (7,8-DHF), a natural compound, was able to decrease the expression of and did not affect the in vitro growth of S. aureus USA300 at a concentration of 32 µg/mL. It was verified by western blot and RT-qPCR that the natural compound could inhibit the transcription and translation of Hla. Further mechanism studies revealed that 7,8-DHF has a negative effect on transcriptional regulator agrA and RNAIII, preventing the upregulation of virulence gene. Cytotoxicity assays showed that 7,8-DHF did not produce significant cytotoxicity to A549 cells. Animal experiments showed that the combination of 7,8-DHF and vancomycin had a more significant therapeutic effect on S. aureus infection, reflecting the synergistic effect of 7,8-DHF with antibiotics. In conclusion, 7,8-DHF was able to target Hla to protect host cells from hemolysis while limiting the development of bacterial resistance.
Assuntos
Toxinas Bacterianas , Flavonas , Infecções Estafilocócicas , Staphylococcus aureus , Células A549 , Animais , Antibacterianos/metabolismo , Antibacterianos/farmacologia , Toxinas Bacterianas/metabolismo , Flavonas/farmacologia , Proteínas Hemolisinas/genética , Humanos , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Staphylococcus aureus/efeitos dos fármacos , Virulência , Fatores de Virulência/genética , Fatores de Virulência/metabolismoRESUMO
Methicillin-resistant Staphylococcus aureus (MRSA) is a multidrug-resistant pathogen that poses a significant risk to global health today. In S. aureus, α-hemolysin is an important virulence factor as it contributes to the capacity of the bacteria to infect the host. Here, we showed that biochanin A (bioA), an isoflavone present in red clover, cabbage and alfalfa, effectively inhibited hemolytic activity at a dose as low as 32 µg/mL. Further, western blot and RT-qPCR data showed that bioA reduced the production and expression of MRSA hemolysin in a dose-dependent manner. In addition, when different concentrations of bioA were added to a coculture system of A549 cells and S. aureus, it could significantly decrease cell injury. Importantly, the in vivo study showed that bioA could protect mice from pneumonia caused by a lethal dose of MRSA, as evidenced by improving their survival and reducing the number of bacterial colonies in lung tissues, the secretion of hemolysin into alveolar lavage fluid and the degree of pulmonary edema. In conclusion, biochanin A protected the host from MRSA infection by inhibiting the expression of the hemolysin of MRSA, which may provide experimental evidence for its development to a potential anti-MRSA drug.
Assuntos
Antibacterianos/administração & dosagem , Genisteína/administração & dosagem , Proteínas Hemolisinas/metabolismo , Staphylococcus aureus Resistente à Meticilina/efeitos dos fármacos , Pneumonia/tratamento farmacológico , Infecções Estafilocócicas/tratamento farmacológico , Células A549 , Animais , Antibacterianos/farmacologia , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Modelos Animais de Doenças , Relação Dose-Resposta a Droga , Feminino , Regulação Bacteriana da Expressão Gênica/efeitos dos fármacos , Genisteína/farmacologia , Proteínas Hemolisinas/genética , Hemólise/efeitos dos fármacos , Humanos , Staphylococcus aureus Resistente à Meticilina/genética , Staphylococcus aureus Resistente à Meticilina/patogenicidade , Camundongos , Pneumonia/microbiologia , Infecções Estafilocócicas/microbiologiaRESUMO
Glutathione peroxidase (GPx) is an antioxidant protein containing selenium. Owing to the limitations of native GPx, considerable efforts have been made to develop GPx mimics. Here, a short 5-mer peptides (5P) was synthesized and characterized using matrix-assisted laser desorption ionization time-of-flight mass spectrometry. Enzyme coupled assays were used to evaluate GPx activity. The cell viability and apoptosis of H22 cells were tested, and mice bearing H22 cell-derived tumors were used to determine the effects of 5P on tumor inhibition. In comparison with other enzyme models, 5P provided a suitable substrate with proper catalytic site positions, resulting in enhanced catalytic activity. In our mouse model, 5P showed excellent inhibition of tumor growth and improved immunity. In summary, our findings demonstrated the design and synthesis of the small 5P molecule, which inhibited tumor growth and improved immunity. Notably, 5P could inhibit tumor growth without affecting normal growth. Based on these advantages, the novel mimic may have several clinical applications.
Assuntos
Antineoplásicos/farmacologia , Antioxidantes/farmacologia , Carcinoma Hepatocelular/tratamento farmacológico , Imunidade Inata/efeitos dos fármacos , Neoplasias Hepáticas/tratamento farmacológico , Oligopeptídeos/farmacologia , Animais , Antineoplásicos/síntese química , Antineoplásicos/metabolismo , Antioxidantes/síntese química , Antioxidantes/metabolismo , Apoptose/efeitos dos fármacos , Biocatálise , Carcinoma Hepatocelular/genética , Carcinoma Hepatocelular/imunologia , Carcinoma Hepatocelular/patologia , Linhagem Celular Tumoral , Sobrevivência Celular/efeitos dos fármacos , Desenho de Fármacos , Pontos de Checagem da Fase G2 do Ciclo Celular/efeitos dos fármacos , Regulação Neoplásica da Expressão Gênica , Glutationa Peroxidase/química , Glutationa Peroxidase/metabolismo , Neoplasias Hepáticas/genética , Neoplasias Hepáticas/imunologia , Neoplasias Hepáticas/patologia , Camundongos , Mimetismo Molecular , Oligopeptídeos/síntese química , Oligopeptídeos/metabolismo , Especificidade de Órgãos , Fagocitose/efeitos dos fármacos , Proteínas Proto-Oncogênicas c-bcl-2/antagonistas & inibidores , Proteínas Proto-Oncogênicas c-bcl-2/genética , Proteínas Proto-Oncogênicas c-bcl-2/imunologia , Resultado do Tratamento , Proteína X Associada a bcl-2/agonistas , Proteína X Associada a bcl-2/genética , Proteína X Associada a bcl-2/imunologiaRESUMO
Limitations in the clinical treatment of Staphylococcus aureus (S. aureus) infections have arisen due to the advent of antibiotic-resistant strains. Given the immense potential of therapeutic strategies targeting bacterial virulence, the role of MgrA as a pivotal virulence determinant in S. aureus-orchestrating resistance, adherence, and hundreds of virulence targets-becomes indispensable. In this investigation, leveraging advanced virtual screening and fluorescence anisotropy assays, we discerned methylophiopogonanone A (Mo-A), a flavonoid derivative, as a potent disruptor of the MgrA-DNA interaction nexus. Subsequent analysis revealed that Mo-A effectively inhibits the expression of virulence factors such as Hla and Pvl in S. aureus and markedly reduces its adhesion capability to fibrinogen. On a cellular landscape, Mo-A exerts a mitigating influence on the deleterious effects inflicted by S. aureus USA300 on A549 cells. Furthermore, our data indicate that Mo-A downregulates the transcription of genes associated with immune evasion, such as nucleases (nuc), Staphylococcal Chemotaxis Inhibitory Protein (chips), and Staphylococcal Complement Inhibitor (scin), thereby undermining immune escape and amplifying neutrophil chemotaxis. Upon application in an in vivo setting, Mo-A assumes a protective persona in a murine model of S. aureus USA300-induced pneumonia and demonstrates efficacy in the Galleria mellonella infection model. Of note, S. aureus displayed no swift acquisition of resistance to Mo-A, and the effect was synergistically enhanced when used in combination with vancomycin. Our findings add substantive weight to the expanding field of virulence-targeted therapeutic strategies and set the stage for more comprehensive exploration of Mo-A potential in combating antibiotic-resistant S. aureus.
Assuntos
Benzodioxóis , Isoflavonas , Staphylococcus aureus Resistente à Meticilina , Infecções Estafilocócicas , Camundongos , Animais , Staphylococcus aureus/genética , Proteínas de Bactérias/genética , Fatores de Virulência/genética , Infecções Estafilocócicas/tratamento farmacológico , Infecções Estafilocócicas/microbiologia , Antibacterianos/metabolismoRESUMO
Current in vitro models struggle to balance the complexity of human diseases with suitability for large-scale drug tests. While 3D cultures simulate human tissues, they lack cellular intricacy, and integrating these models with high-throughput drug screening remains a challenge. Here, we introduce a method that uses self-assembling nucleic acid nanostructures decorated living cells, termed NACs, to create spheroids with a customizable 3D layout. To demonstrate its uniqueness, our method effectively creates designer 3D spheroids by combining parenchymal cells, stromal cells, and immune cells, leading to heightened physiological relevance and detailed modeling of complex chronic diseases and immune-stromal interactions. Our approach achieves a high level of biological fidelity while being standardized and straightforward to construct with the potential for large-scale drug discovery applications. By merging the precision of DNA nanotechnology with advanced cell culture techniques, we are streamlining human-centric models, striking a balance between complexity and standardization, to boost drug screening efficiency.
Assuntos
DNA , Avaliação Pré-Clínica de Medicamentos , Esferoides Celulares , Humanos , Esferoides Celulares/efeitos dos fármacos , DNA/química , Avaliação Pré-Clínica de Medicamentos/métodos , Nanotecnologia/métodos , Nanoestruturas/químicaRESUMO
BACKGROUND: Patients diagnosed with advanced stage cancer face an elevated risk of suicide. We aimed to develop a suicidal ideation (SI) risk prediction model in patients with advanced cancer for early warning of their SI and facilitate suicide prevention in this population. PATIENTS AND METHODS: We consecutively enrolled patients with multiple types of advanced cancers from 10 cancer institutes in China from August 2019 to December 2020. Demographic characteristics, clinicopathological data, and clinical treatment history were extracted from medical records. Symptom burden, psychological status, and SI were assessed using the MD Anderson Symptom Inventory (MDASI), Hospital Anxiety and Depression Scale (HADS), and Patient Health Questionnaire-9 (PHQ-9), respectively. A multivariable logistic regression model was employed to establish the model structure. RESULTS: In total, 2814 participants were included in the final analysis. Nine predictors including age, sex, number of household members, history of previous chemotherapy, history of previous surgery, MDASI score, HADS-A score, HADS-D score, and life satisfaction were retained in the final SI prediction model. The model achieved an area under the curve (AUC) of 0.85 (95% confidential interval: 0.82-0.87), with AUCs ranging from 0.75 to 0.95 across 10 hospitals and higher than 0.83 for all cancer types. CONCLUSION: This study built an easy-to-use, good-performance predictive model for SI. Implementation of this model could facilitate the incorporation of psychosocial support for suicide prevention into the standard care of patients with advanced cancer.