RESUMO
BACKGROUNDS: Non-alcoholic fatty liver disease (NAFLD) is one of the most prevalent chronic liver diseases. The leaves of Broussonetia papyrifera contain a large number of flavonoids, which have a variety of biological functions. METHODS: In vitro experiments, free fatty acids were used to stimulate HepG2 cells. NAFLD model was established in vivo in mice fed with high fat diet (HFD) or intraperitoneally injected with Tyloxapol (Ty). At the same time, Total flavonoids of Broussonetia papyrifera (TFBP) was used to interfere with HepG2 cells or mice. RESULTS: The results showed that TFBP significantly decreased the lipid accumulation induced by oil acid (OA) with palmitic acid (PA) in HepG2 cells. TFBP decreased the total cholesterol (TC), the triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), and increased high-density lipoprotein cholesterol (HDLC) in serum. TFBP could also effectively inhibit the generation of reactive oxygen species (ROS) and restrained the level of myeloperoxidase (MPO), and enhance the activity of superoxide dismutase (SOD) to alleviate the injury from oxidative stress in the liver. Additionally, TFBP activated nuclear factor erythroid-2-related factor 2 (Nrf2) pathway to increasing the phosphorylation of AMP-activated protein kinase (AMPK). Meanwhile, protein levels of mTORC signaling pathway were evidently restrained with the treatment of TFBP. CONCLUSION: Our experiments proved that TFBP has the therapeutic effect in NAFLD, and the activation of Nrf2 and AMPK signaling pathways should make sense.
Assuntos
Proteínas Quinases Ativadas por AMP , Broussonetia , Flavonoides , Fator 2 Relacionado a NF-E2 , Hepatopatia Gordurosa não Alcoólica , Transdução de Sinais , Serina-Treonina Quinases TOR , Animais , Humanos , Camundongos , Proteínas Quinases Ativadas por AMP/efeitos dos fármacos , Proteínas Quinases Ativadas por AMP/metabolismo , Broussonetia/química , Dieta Hiperlipídica/efeitos adversos , Flavonoides/farmacologia , Células Hep G2/efeitos dos fármacos , Metabolismo dos Lipídeos/efeitos dos fármacos , Camundongos Endogâmicos C57BL , Fator 2 Relacionado a NF-E2/efeitos dos fármacos , Fator 2 Relacionado a NF-E2/metabolismo , Hepatopatia Gordurosa não Alcoólica/metabolismo , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Espécies Reativas de Oxigênio/metabolismo , Transdução de Sinais/efeitos dos fármacos , Serina-Treonina Quinases TOR/efeitos dos fármacos , Serina-Treonina Quinases TOR/metabolismoRESUMO
Oncogenic RAS and RAF signaling has been implicated in contributing to radioresistance in pancreatic and thyroid cancers. In this study, we sought to better clarify molecular mechanisms contributing to this effect. We discovered that miRNA 296-3p (miR-296-3p) is significantly correlated with radiosensitivity in a panel of pancreatic cancer cells, and miR-296-3p is highly expressed in normal cells, but low in cancer cell lines. Elevated expression of miR-296-3p increases radiosensitization while decreasing the expression of the DNA repair enzyme RAD18 in both pancreatic and thyroid cancer cells. RAD18 is overexpressed in both pancreatic and thyroid tumors compared to matched normal controls, and high expression of RAD18 in tumors is associated with poor prognostic features. Modulating the expression of mutant KRAS in pancreatic cancer cells or mutant BRAF in thyroid cancer cells demonstrates a tight regulation of RAD18 expression in both cancer types. Depletion of RAD18 results in DNA damage and radiation-induced cell death. Importantly, RAD18 depletion in combination with radiotherapy results in marked and sustained tumor regression in KRAS mutant pancreatic cancer orthotopic tumors and BRAF mutant thyroid heterotopic tumors. Overall, our findings identify a novel coordinated RAS/RAF-miR-296-3p-RAD18 signaling network in pancreatic and thyroid cancer cells, which leads to enhanced radioresistance.
Assuntos
Proteínas de Ligação a DNA , Regulação Neoplásica da Expressão Gênica , MicroRNAs , Neoplasias Pancreáticas , Proteínas Proto-Oncogênicas p21(ras) , Tolerância a Radiação , Transdução de Sinais , Neoplasias da Glândula Tireoide , Humanos , MicroRNAs/genética , MicroRNAs/metabolismo , Tolerância a Radiação/genética , Neoplasias Pancreáticas/genética , Neoplasias Pancreáticas/radioterapia , Neoplasias Pancreáticas/patologia , Neoplasias Pancreáticas/metabolismo , Neoplasias da Glândula Tireoide/genética , Neoplasias da Glândula Tireoide/radioterapia , Neoplasias da Glândula Tireoide/patologia , Neoplasias da Glândula Tireoide/metabolismo , Linhagem Celular Tumoral , Animais , Proteínas de Ligação a DNA/genética , Proteínas de Ligação a DNA/metabolismo , Proteínas Proto-Oncogênicas p21(ras)/genética , Proteínas Proto-Oncogênicas p21(ras)/metabolismo , Proteínas Proto-Oncogênicas B-raf/genética , Camundongos Nus , Mutação , Dano ao DNA , Ensaios Antitumorais Modelo de Xenoenxerto , Proteínas ras/genética , Proteínas ras/metabolismo , TransfecçãoRESUMO
IMPORTANCE: Salmonella spp. remains a major worldwide health concern that causes significant morbidity and mortality in both humans and animals. The spread of antimicrobial resistant strains has declined the efficacy of conventional chemotherapy. Thus, novel anti-infection drugs or strategies are needed. Anti-virulence strategy represents one of the promising means for the treatment of bacterial infections. In this study, we found that the natural compound fisetin could inhibit Salmonella invasion of host cells by targeting SPI-1 regulation. Fisetin treatment impaired the interaction of the regulatory protein HilD with the promoters of its target genes, thereby suppressing the expression of T3SS-1 effectors as well as structural proteins. Moreover, fisetin treatment could reduce pathology in the Salmonella murine infection model. Collectively, our results suggest that fisetin may serve as a promising lead compound for the development of anti-Salmonella drugs.
Assuntos
Flavonóis , Infecções por Salmonella , Salmonella typhimurium , Humanos , Animais , Camundongos , Salmonella typhimurium/genética , Sistemas de Secreção Tipo III/metabolismo , Infecções por Salmonella/tratamento farmacológico , Infecções por Salmonella/microbiologia , Fatores de Transcrição/metabolismo , Proteínas de Bactérias/genética , Proteínas de Bactérias/metabolismo , Regulação Bacteriana da Expressão GênicaRESUMO
BACKGROUND AND PURPOSE: The production of metallo-ß-lactamases is a major mechanisms adopted by bacterial pathogens to resist carbapenems. Repurposing approved drugs to restore the efficacy of carbapenems represents an efficient and cost-effective approach to fight infections caused by carbapenem resistant pathogens. EXPERIMENTAL APPROACH: The nitrocefin hydrolysis assay was employed to screen potential New Delhi metallo-lactamase-1 (NDM-1) inhibitors from a commercially available U.S. Food and Drug Administration (FDA) approved drug library. The mechanism of inhibition was clarified by metal restoration, inductively coupled plasma mass spectrometry (ICP-MS) and molecular dynamics simulation. The in vitro synergistic antibacterial effect of the identified inhibitors with meropenem was determined by the checkerboard minimum inhibitory concentration (MIC) assay, time-dependent killing assay and combined disc test. Three mouse infection models were used to further evaluate the in vivo therapeutic efficacy of combined therapy. KEY RESULTS: Twelve FDA-approved compounds were initially screened to inhibit the ability of NDM-1 to hydrolyse nitrocefin. Among these compounds, dexrazoxane, embelin, candesartan cilexetil and nordihydroguaiaretic acid were demonstrated to inhibit all tested metallo-ß-lactamases and showed an in vitro synergistic bactericidal effect with meropenem against metallo-ß-lactamases-producing bacteria. Dexrazoxane, embelin and candesartan cilexetil are metal ion chelating agents, while the inhibition of NDM-1 by nordihydroguaiaretic acid involves its direct binding to the active region of NDM-1. Furthermore, these four drugs dramatically rescued the treatment efficacy of meropenem in three infection models. CONCLUSIONS AND IMPLICATIONS: Our observations indicated that dexrazoxane, embelin, candesartan cilexetil and nordihydroguaiaretic acid are promising carbapenem adjuvants against metallo-ß-lactamases-positive carbapenem resistant bacterial pathogens.
Assuntos
Carbapenêmicos , Dexrazoxano , Animais , Camundongos , Carbapenêmicos/farmacologia , Carbapenêmicos/química , Meropeném/farmacologia , Inibidores de beta-Lactamases/farmacologia , Masoprocol , Antibacterianos/farmacologia , beta-Lactamases/metabolismo , Bactérias/metabolismo , Testes de Sensibilidade MicrobianaRESUMO
AIMS: Clostridium perfringens infections affect food safety, human health, and the development of the poultry feed industry. Anti-virulence is an alternative strategy to develop new drug. Perfringolysin O (PFO) is an exotoxin of C. perfringens that has been demonstrated to play critical roles in the pathogenesis of this organism, promising it an attractive target to explore drugs to combat C. perfringens infection. METHODS AND RESULTS: Based on an activity-based screening, we identified six PFO inhibitors from the Food and Drug Administration (FDA)-approved drug library, among which rabeprazole sodium (RS) showed an optimal inhibitory effect with an IC50 of 1.82 ± 0.746 µg ml-1. The GLY57, ASP58, SER190, SER193-194, ASN199, GLU204, ASN377, THR379, and ALA200 in PFO interacted with RS during binding based on an energy analysis and H-bond analysis. This interaction blocked the oligomer formation of PFO, thereby inhibiting its cytotoxicity. RS treatment significantly increased the survival rate and alleviated pathological damage in C. perfringens or PFO-treated Galleria mellonella. CONCLUSIONS: RS could potentially be used as a candidate drug for treating C. perfringens infection.
Assuntos
Infecções por Clostridium , Clostridium perfringens , Humanos , Rabeprazol/farmacologia , Rabeprazol/metabolismo , Reposicionamento de Medicamentos , Proteínas Hemolisinas/farmacologia , Proteínas Hemolisinas/metabolismoRESUMO
Glioblastoma (GBM) is an aggressive malignant primary brain tumor. Radioresistance largely contributes to poor clinical outcomes in GBM patients. We targeted ribonucleotide reductase subunit 2 (RRM2) with triapine to radiosensitize GBM. We found RRM2 is associated with increasing tumor grade, is overexpressed in GBM over lower grade gliomas and normal tissue, and is associated with worse survival. We found silencing or inhibition of RRM2 by siRNA or triapine sensitized GBM cells to ionizing radiation (IR) and delayed resolution of IR-induced γ-H2AX nuclear foci. In vivo, triapine and IR reduced tumor growth and increased mouse survival. Intriguingly, triapine led to RRM2 upregulation and CHK1 activation, suggesting a CHK1-dependent RRM2 upregulation following RRM2 inhibition. Consistently, silencing or inhibition of CHK1 with rabusertib abolished the triapine-induced RRM2 upregulation. Accordingly, combining rabusertib and triapine resulted in synthetic lethality in GBM cells. Collectively, our results suggest RRM2 is a promising therapeutic target for GBM, and targeting RRM2 with triapine sensitizes GBM cells to radiation and independently induces synthetic lethality of GBM cells with CHK1 inhibition. Our findings suggest combining triapine with radiation or rabusertib may improve therapeutic outcomes in GBM.
Assuntos
Glioblastoma , Animais , Camundongos , Linhagem Celular Tumoral , Glioblastoma/tratamento farmacológico , Glioblastoma/genética , Glioblastoma/radioterapia , Piridinas/farmacologia , Mutações Sintéticas LetaisRESUMO
Osteosarcoma (OS) is the most common primary bone cancer in children and adolescents. In clinical treatments, the insensitivity of OS to conventional radiotherapy regimens significantly contributes to poor patient prognosis and survival. EXO1 is responsible for DNA repair pathways and telomere maintenance. Meanwhile, ATM and ATR are considered switches because they can regulate the expression of EXO1. However, their expression and interaction in OS cells under irradiation (IR) remain unclear. This study aims to investigate the roles of FBXO32, ATM, ATR and EXO1 in OS radiotherapy insensitivity and poor patient prognosis and explore potential pathogenic mechanisms. Bioinformatics is employed to analyse differential gene expression and correlations with prognosis in OS. Cell counting kit 8 assay, clone formation assay, and flow cytometry are used to evaluate cell survival and apopotosis under IR. Co-IP assay is used to detect proteinâprotein interactions. Bioinformatics analysis reveals that EXO1 is closely related to survival, apoptosis and poor prognosis in OS. Silencing of EXO1 suppresses cell proliferation and increases the sensitivity of OS cells. Molecular biological experiments show that ATM and ATR act as switches to regulate EXO1 expression under IR. Higher expression of EXO1, which is closely correlated with IR insensitivity and poorer prognosis, might be used as a prognostic indicator for OS. Phosphorylated ATM enhances the expression of EXO1, and phosphorylated ATR induces the degradation of EXO1. More importantly, FBXO32 degrades ATR via ubiquitination in a time-dependent manner. Our data may provide a reference for future research in the mechanisms, clinical diagnosis, and treatment of OS.
Assuntos
Neoplasias Ósseas , Osteossarcoma , Criança , Humanos , Adolescente , Proteínas Mutadas de Ataxia Telangiectasia/genética , Proteínas Mutadas de Ataxia Telangiectasia/metabolismo , Osteossarcoma/genética , Osteossarcoma/radioterapia , Osteossarcoma/metabolismo , Sobrevivência Celular , Proliferação de Células/genética , Neoplasias Ósseas/genética , Neoplasias Ósseas/radioterapia , Neoplasias Ósseas/metabolismo , Linhagem Celular Tumoral , Exodesoxirribonucleases/genética , Exodesoxirribonucleases/metabolismo , Enzimas Reparadoras do DNA/genética , Proteínas Musculares/metabolismo , Proteínas Ligases SKP Culina F-Box/metabolismoRESUMO
BACKGROUND: Non-alcoholic fatty liver disease (NAFLD) is a common metabolic liver disease worldwide. It has been proven that aescin (Aes), a bioactive compound derived from the ripe dried fruit of Aesculus chinensis Bunge, has a number of physiologically active properties like anti-inflammatory and anti-edema, however it has not been investigated as a potential solution for NAFLD. PURPOSE: This study's major goal was to determine whether Aes can treat NAFLD and the mechanism underlying its therapeutic benefits. METHODS: We constructed HepG2 cell models in vitro that were affected by oleic and palmitic acids, as well as in vivo models for acute lipid metabolism disorder caused by tyloxapol and chronic NAFLD caused by high-fat diet. RESULTS: We discovered that Aes could promote autophagy, activate the Nrf2 pathway, and ameliorate lipid accumulation and oxidative stress both in vitro and in vivo. Nevertheless, in Autophagy-related proteins 5 (Atg5) and Nrf2 knockout mice, Aes lost its curative impact on NAFLD. Computer simulations show that Aes might interact with Keap1, which might allow Aes to increase Nrf2 transfer into the nucleus and perform its function. Importantly, Aes's stimulation of autophagy in the liver was hampered in Nrf2 knockout mice. This suggested that the impact of Aes in inducing autophagy may be connected to the Nrf2 pathway. CONCLUSION: We first discovered Aes's regulating effects on liver autophagy and oxidative stress in NAFLD. And we found Aes may combine the Keap1 and regulate autophagy in the liver by affecting Nrf2 activation to exert its protective effect.
Assuntos
Antioxidantes , Hepatopatia Gordurosa não Alcoólica , Camundongos , Animais , Antioxidantes/farmacologia , Antioxidantes/metabolismo , Hepatopatia Gordurosa não Alcoólica/tratamento farmacológico , Hepatopatia Gordurosa não Alcoólica/metabolismo , Proteína 1 Associada a ECH Semelhante a Kelch/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Escina/metabolismo , Fígado/metabolismo , Estresse Oxidativo , Autofagia , Camundongos Knockout , Dieta Hiperlipídica/efeitos adversos , Camundongos Endogâmicos C57BLRESUMO
BACKGROUND: NAFLD is a liver disease that is caused by liver damage or extreme lipid deposition but not alcohol. Nrf2 could mediate resistance to oxidative stress injury. Autophagy can degrade metabolic waste and accumulated toxic endogenous substances. Pterostilbene (PTE) is an active compound extracted from blueberry, and grape, that exhibits many biological effects, such as antiinflammation and antitumor. PURPOSE: This study provides a mechanism of PTE affecting on oxidative stress and autophagy in NAFLD mice. Tyloxapol, oil acid (OA) and palmitic acid (PA) were used to induce lipid accumulation in mice and HepG2 cells. METHODS: Western blotting, CRISPR/Cas 9 and other molecular biological approaches were applied to explore the mechanisms of PTE effected on NAFLD. RESULTS: PTE pretreatment effectively reduced the lipid accumulation in OA and PA induced HepG2 cells and tyloxapol induced mice, and significantly promoted the expression of nNrf2, PPAR-α and HO-1, and AMPK activity, but inhibited the expression of mTORC 1 and SREBP-1c. PTE activated phosphatidylinositide 3-kinase (PI3K) and proteins in the autophagy-related gene (ATG) family, and promoted the transformation of LC3â to LC3â ¡ which indicated the activation of autophagy, however, these effects were abolished after Nrf2 knockout. CONCLUSION: PTE effectively alleviated oxidative stress damage induced by excessive lipid accumulation in hepatocytes, thus promoting the metabolism and decomposition of fatty acids to improve NAFLD.
Assuntos
Hepatopatia Gordurosa não Alcoólica , Animais , Camundongos , Hepatopatia Gordurosa não Alcoólica/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Transdução de Sinais , Serina-Treonina Quinases TOR/metabolismo , Estresse Oxidativo , Autofagia , Ácidos Graxos , Metabolismo dos Lipídeos , Camundongos Endogâmicos C57BLRESUMO
High blood concentrations of nonesterified fatty acids (NEFAs) provoke various metabolic disorders and are associated with mammary tissue injury and decreased milk production in dairy cows. Nuciferine, an alkaloid found in Nelumbo nucifera leaves, has great potential for correcting lipid metabolism derangements and lipotoxicity. In this study, we evaluated the lipotoxicity induced by excessive NEFA in bovine mammary epithelial cells (bMECs) and investigated whether nuciferine alleviates NEFA-induced lipotoxicity and the underlying molecular mechanisms. We found that excessive NEFA (1.2 and 2.4 mM) induced lipid accumulation, apoptosis, and migration ability impairment in bMECs, whereas nuciferine could ameliorate these disarrangements, as indicated by decreasing triglyceride content, protein abundance of SREBP-1c, cytoplasmic cytochrome c, and cleaved caspase-3 and increasing protein abundance of PPARα and migration ability. Moreover, nuciferine could reverse NEFA-induced LKB1/AMPK signaling inhibition, and the protective effect of nuciferine on lipotoxicity caused by NEFA was abrogated by AMPK inhibitor dorsomorphin. Furthermore, transfection with LKB1 siRNA (si-LKB1) largely abolished the activation effect of nuciferine on AMPK. Overall, nuciferine can protect bMECs from excessive NEFA-induced lipid accumulation, apoptosis, and impaired migration by activating LKB1/AMPK signaling pathway.
Assuntos
Proteínas Quinases Ativadas por AMP , Ácidos Graxos não Esterificados , Animais , Bovinos , Feminino , Proteínas Quinases Ativadas por AMP/genética , Proteínas Quinases Ativadas por AMP/metabolismo , Apoptose , Células Epiteliais/metabolismo , Ácidos Graxos não Esterificados/toxicidade , Metabolismo dos Lipídeos , Transdução de Sinais , Quinases Proteína-Quinases Ativadas por AMP/metabolismoRESUMO
Co-infections with pathogens and secondary bacterial infections play significant roles during the pandemic coronavirus disease 2019 (COVID-19) pathogenetic process, caused by Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Notably, co-infections with Streptococcus pneumoniae (S. pneumoniae), as a major Gram-positive pathogen causing pneumonia or meningitis, severely threaten the diagnosis, therapy, and prognosis of COVID-19 worldwide. Accumulating evidences have emerged indicating that S. pneumoniae evolves multiple virulence factors, including pneumolysin (PLY) and sortase A (SrtA), which have been extensively explored as alternative anti-infection targets. In our study, natural flavonoid kaempferol was identified as a potential candidate drug for infection therapeutics via anti-virulence mechanisms. We found that kaempferol could interfere with the pore-forming activity of PLY by engaging with catalytic active sites and consequently inhibit PLY-mediated cytotoxicity. Additionally, exposed to kaempferol significantly reduced the SrtA peptidase activity by occupying the active sites of SrtA. Further, the biofilms formation and bacterial adhesion to the host cells could be significantly thwarted by kaempferol incubation. In vivo infection model by S. pneumoniae highlighted that kaempferol oral administration exhibited notable treatment benefits, as evidenced by decreased bacterial burden, suggesting that kaempferol has tremendous potential to attenuate S. pneumoniae pathogenicity. Scientifically, our study implies that kaempferol is a promising therapeutic option by targeting bacterial virulence factors.
Assuntos
COVID-19 , Coinfecção , Infecções Pneumocócicas , Humanos , Quempferóis/farmacologia , Quempferóis/uso terapêutico , SARS-CoV-2 , Infecções Pneumocócicas/tratamento farmacológico , Infecções Pneumocócicas/microbiologia , Streptococcus pneumoniae , Fatores de Virulência , Proteínas de BactériasRESUMO
BACKGROUND: Carbon tetrachloride (CCl4) is highly toxic to animal liver and is a major contributor to liver injury. Gomphrena globosa L. (GgL) is an edible plant with anti-inflammation and antioxidation properties. The aim of this study was to investigate the potential therapeutic effects of GgL on liver injury. METHODS AND RESULTS: A model of chronic liver injury in mice was established by intraperitoneal injection of CCl4 (0.4 mL/kg) for 3 weeks, and the mice were treated intraperitoneally with different concentrations of GgL crude extract (GgCE; 100, 200, 300 mg/kg) or Bifendatatum (Bif; 20 mg/kg) in the last 2 weeks. The results showed that GgCE treatment alleviated the liver injury, improved the pathological changes caused by CCl4 on the mice liver, and enhance the antioxidant capacity. We also found that GgCE increased the expression of antioxidant stress related proteins, decreased the phosphorylation levels of autophagy related proteins PI3K and mTOR, and decreased the expression of LC3 II and P62 proteins. CONCLUSION: These results suggest that GgCE alleviated CCl4-induced chronic liver injury in mice by activating antioxidant signaling pathways and promoting autophagy, indicating a potential therapeutic effect of GgCE on liver injury.
Assuntos
Doença Hepática Crônica Induzida por Substâncias e Drogas , Doença Hepática Induzida por Substâncias e Drogas , Camundongos , Animais , Antioxidantes/farmacologia , Antioxidantes/metabolismo , Doença Hepática Crônica Induzida por Substâncias e Drogas/metabolismo , Doença Hepática Crônica Induzida por Substâncias e Drogas/patologia , Fígado/metabolismo , Transdução de Sinais , Tetracloreto de Carbono/farmacologia , Autofagia , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Estresse OxidativoRESUMO
The undesired distribution of irregular surface astigmatism (SA) on the freeform surface has been the major concern of progressive addition lens (PAL) design. Herein, we proposed a segmented freeform surface (SFS) construction method, which relies on the lines of curvature to rule the surface segmentation and then eliminates the difference between principal curvatures to correct the SA. Based on ray tracing and numerical simulation results, the SFS-PAL design has superior performance in image quality within a dynamic field of view over the conventional freeform PAL. To verify the feasibility and the real performance of the new design, we used the diamond turning method with a fast tool servo to realize the rapid prototyping, and then used injection molding for the mass production of the high-quality SFS-PALs.
RESUMO
Background: Listeria monocytogenes (L. monocytogenes), as a pandemic foodborne pathogen, severely threatens food security and public health care worldwide, which evolves multiple bacterial virulence factors (such as listeriolysin O, LLO) for manipulating the immune response of L. monocytogenes-host interactions. Methods: Hemolysis assay was employed to screen a potential LLO inhibitor and the underlying mechanisms were investigated using molecular dynamics (MD) simulation and oligomerization assay. The effects of candidates on immune response were examined by qRT-PCR and immunoblotting analysis. Histological analysis, ELISA assay and biochemistry detection were conducted to assess in vivo efficacy of candidates. Results: In the present study, natural terpenoid atractylodin was characterized as an alternative drug candidate for the treatment of L. monocytogenes by the regulation of LLO function and host Nrf2/NLRP3 signaling pathway. Notably, in vivo infection model by L. monocytogenes also highlighted that atractylodin treatment provided effective therapeutic benefits, as evidenced by decreased bacterial burden and diminished inflammation. Congruently, the survival rate of L. monocytogenes-infection mice increased significantly from 10.0% to 40.0% by atractylodin treatment. Conclusion: Collectively, our study showed for the first time that atractylodin has tremendous potential to attenuate L. monocytogenes pathogenicity by blocking LLO pore formation and mediating the suppression of inflammation and oxidative stress, providing a promising therapeutic strategy and broadening the applications of atractylodin against L. monocytogenes infection.
Assuntos
Listeria monocytogenes , Listeriose , Camundongos , Animais , Virulência , Antioxidantes/farmacologia , Antioxidantes/uso terapêutico , Antioxidantes/metabolismo , Listeriose/tratamento farmacológico , Listeriose/microbiologia , Anti-Inflamatórios/farmacologia , Anti-Inflamatórios/uso terapêutico , Anti-Inflamatórios/metabolismo , Inflamação/tratamento farmacológicoRESUMO
Overdose of acetaminophen (APAP) is currently one of the main causes of hepatoxicity and acute liver injury, which is often linked to oxidative stress. Phellinus linteus polysaccharides (Phps) have shown many hepatoprotective effects, however, the mechanism of Phps on APAP-induced acute liver injury has not been further elucidated. The aim of this study is to investigate the underlying mechanism of Phps to acute liver injury. The expression of AMPK/Nrf2 and autophagy were detected using western blot. The results indicated that Phps treatment effectively alleviated APAP-induced acute liver injury by reducing alanine transaminase (ALT) and aspartate aminotransferase (AST) levels in serum. Phps significantly attenuated myeloperoxidase (MPO) activity and glutathione (GSH) depletion. Meanwhile, Phps remarkably alleviated histopathological changes. Further research found that Phps promoted AMPK pathway and up-regulated nuclear factor erythroid-2-related factor (Nrf2) transported into nucleus, and elevated heme oxygenase 1(HO-1), glutamate-cysteine ligase catalytic (GCLC), glutamate cysteine ligase modifier (GCLM) and quinone oxidoreductase (NQO1). Additionally, Phps apparently facilitated the expression of autophagy proteins (ATG3, ATG5, ATG7, and ATG12). However, the protection of pathologic changes was nearly absent in Nrf2-/- mice. Phps have potential in preventing oxidative stress in APAP-induced acute liver injury.
Assuntos
Acetaminofen , Doença Hepática Induzida por Substâncias e Drogas , Animais , Camundongos , Acetaminofen/toxicidade , Alanina Transaminase/metabolismo , Proteínas Quinases Ativadas por AMP/metabolismo , Aspartato Aminotransferases/metabolismo , Basidiomycota , Doença Hepática Induzida por Substâncias e Drogas/metabolismo , Glutamato-Cisteína Ligase/metabolismo , Glutationa/metabolismo , Heme Oxigenase-1/metabolismo , Fígado/metabolismo , Fator 2 Relacionado a NF-E2/metabolismo , Estresse Oxidativo , Peroxidase/metabolismo , Polissacarídeos/metabolismo , Polissacarídeos/farmacologia , Quinonas/metabolismo , Quinonas/farmacologia , Transdução de SinaisRESUMO
Clostridium perfringens (C. perfringens) is an important foodborne pathogen that can cause diseases such as gas gangrene and necrotizing enteritis in a variety of economic animals, seriously affecting public health and the economic benefits and healthy development of the livestock and poultry breeding industry. Perfringolysin O (PFO) is an important virulence factor of C. perfringens and plays critical roles in necrotic enteritis and gas gangrene, rendering it an ideal target for developing new drugs against infections caused by this pathogen. In this study, based on biological activity inhibition assays, oligomerization tests and computational biology assays, we found that the foodborne natural component piceatannol reduced pore-forming activity with an inhibitory ratio of 83.84% in the concentration of 16 µg/mL (IC50 = 7.83 µg/mL) by binding with PFO directly and changing some of its secondary structures, including 3-Helix, A-helix, bend, and in turn, ultimately affecting oligomer formation. Furthermore, we confirmed that piceatannol protected human intestinal epithelial cells from the damage induced by PFO with LDH release reduced by 38.44% at 16 µg/mL, based on a cytotoxicity test. By performing an animal experiment, we found the C. perfringens clones showed an approximate 10-fold reduction in infected mice. These results suggest that piceatannol may be a candidate for anti-C. perfringens drug development.
Assuntos
Enterite , Gangrena Gasosa , Doenças das Aves Domésticas , Animais , Toxinas Bacterianas , Clostridium perfringens , Proteínas Hemolisinas , Humanos , Camundongos , Estilbenos , VirulênciaRESUMO
ETHNOPHARMACOLOGICAL RELEVANCE: Genkwa flos (yuanhua in Chinese), the dried flower buds of the plant Daphne genkwa Siebold & Zucc., as a traditional herb widely used for the treatment of inflammation-related symptoms and diseases, with the efficacies of diuretic, phlegm-resolving and cough suppressant. AIM OF THE STUDY: Traditional Chinese Medicine (TCM) is presumed to be of immense potential against pathogens infection. Whereas, the potential efficacy and mechanisms of Genkwa flos against L. monocytogenes infection has not been extensively explored. The present study aimed to identify the bioactive ingredients of Genkwa flos against L. monocytogenes infection and to delineate the underlying mechanisms of action. MATERIALS AND METHODS: Bioinformatics approach at protein network level was employed to investigate the therapeutic mechanisms of Genkwa flos against L. monocytogenes infection. And hemolysis inhibition assay, cytoprotection test, western blotting, oligomerization assay and molecular docking analysis were applied to substantiate the multiple efficacies of Genkwa flos and the bioactive ingredient genkwanin. Histopathological analysis and biochemistry detection were conducted to evaluate the in vivo protective effect of genkwanin. RESULTS: Network pharmacology and experimental validation revealed that Traditional Chinese Medicine (TCM) Genkwa flos exhibited anti-L. monocytogenes potency and was found to inhibit the hemolytic activity of LLO. Bioactive ingredient genkwanin interfered with the pore-forming activity of LLO by engaging the active residues Tyr414, Tyr98, Asn473, Val100, Tyr440 and Val438, and thereby attenuated LLO-mediated cytotoxicity. Consistent with the bioinformatics prediction, exposed to genkwanin could upregulate the Nrf2 level and promote the translocation of Nrf2. In vivo, genkwanin oral administration (80 mg/kg) significantly protected against systemic L. monocytogenes infection, as evidenced by reduced myeloperoxidase (MPO) and malondialdehyde (MDA) levels, increased mice survival rate by 30% and decreased pathogen colonization. CONCLUSION: Our study demonstrated that Genkwa flos is a potential anti-L. monocytogenes TCM, highlighted the therapeutic potential of Genkwa flos active ingredient genkwanin by targeting the pore-forming cytolysin LLO and acting as a promising antioxidative candidate against L. monocytogenes infection.
Assuntos
Listeria monocytogenes , Fator 2 Relacionado a NF-E2 , Animais , Flavonas , Flavonoides/análise , Flavonoides/farmacologia , Flavonoides/uso terapêutico , Flores/química , Camundongos , Simulação de Acoplamento MolecularRESUMO
BACKGROUND: Tigecycline is one of the few last-resort antibiotics for the treatment of carbapenem-resistant Enterobacteriaceae infection, the incidence of which has been rapidly increasing. However, the emergence and spread of tigecycline resistance genes tet(X) (including tet(X3) and tet(X4)) has largely compromised the efficient usage of tetracyclines in the clinical settings. METHODS: The synergistic effect was determined by a checkerboard minimum inhibitory concentration (MIC) assay, a time-killing assay and scanning electron microscopy (SEM) analysis. In-depth mechanisms were defined using an enzyme inhibition assay, western blotting, RT-PCR analysis, molecular dynamics (MD) simulations, biolayer interferometry (BLI) assay and metabolomics analysis. FINDINGS: Herein, our work identified a natural compound, plumbagin, as an effective broad-spectrum inhibitor of Tet(X) (also known as monooxygenase) by simultaneously inhibiting the activity and the production of Tet(X3)/Tet(X4). Plumbagin in combination with tetracyclines showed a synergistic bactericidal effect against Tet(X3)/Tet(X4)-producing bacteria. Mechanistic studies revealed that direct engagement of plumbagin with the catalytic pocket of Tet(X3)/Tet(X4) induced an alternation in its secondary structure to inhibit the activity of these monooxygenases. As a consequence, monotherapy or combination therapy with plumbagin increases the oxidative stress and metabolism in bacteria. Moreover, in a mouse systemic infection model of tet(X4)-positive E. coli, the combination of plumbagin and methacycline exhibited remarkable treatment benefits, as shown by a reduced bacterial load and the alleviation of pathological injury. INTERPRETATION: Plumbagin, as an inhibitor of Tet(X3)/Tet(X4), represents a promising lead drug, as well as an adjunct with tetracyclines to treat bacterial infections, especially for extensively drug-resistant bacteria harbouring Tet(X3)/Tet(X4). FUNDING: The National Natural Science Foundation of China.
Assuntos
Escherichia coli , Tetraciclinas , Animais , Antibacterianos/farmacologia , Bactérias/metabolismo , Escherichia coli/genética , Camundongos , Testes de Sensibilidade Microbiana , Oxigenases de Função Mista/genética , Plasmídeos , Tetraciclinas/metabolismo , Tetraciclinas/farmacologia , Tigeciclina/metabolismo , Tigeciclina/farmacologiaRESUMO
It is well known that gut microbiota imbalance can promote the development of metabolic disease. Enterobacter cloacae (E. cloacae) is a kind of opportunistic pathogen in the intestine. Therefore, we hypothesized that E. cloacae accelerated the development of metabolic disease. To answer this question, we used E. cloacae to induce disease in guinea pigs. We used H&E staining to detect the pathological changes of liver and aorta and used Oil Red O staining to evaluate the lipid accumulation in the liver. And that we used a kit to detect AST content and used Western blot to detect protein levels in the liver. We found that E. cloacae could induce liver pathological changes and lipid accumulation as well as aortic wall pathological changes in guinea pigs. And E. cloacae increased the liver index to 5.94% and the serum AST level to 41.93 U/L. Importantly, E. cloacae activated liver high mobility group protein (HMGB1)/toll-like receptor 4 (TLR4)/myeloiddifferentiationfactor88 (MYD88)/nuclear factor-kappa B (NF-κB) signal and sterol regulatory element-binding protein 1c (SREBP-1c) and inhibited AMP-activated protein kinase (AMPK). We conclude that E. cloacae promote nonalcoholic fatty liver disease (NAFLD) by inducing inflammation and lipid accumulation, and E. cloacae also promote atherosclerosis. These findings are important for study on the pathogenesis and drug screening of NAFLD and atherosclerosis.
Assuntos
Aterosclerose/etiologia , Infecções por Enterobacteriaceae/patologia , Fígado/patologia , Hepatopatia Gordurosa não Alcoólica/etiologia , Animais , Aorta/patologia , Aspartato Aminotransferases/sangue , Enterobacter cloacae/patogenicidade , Cobaias , Inflamação , Metabolismo dos Lipídeos , Fígado/metabolismo , MasculinoRESUMO
Porcine hemagglutinating encephalomyelitis virus (PHEV) is a neurotropic coronavirus and highly pathogenic in veterinary clinic. Spike (S) protein of PHEV interplays with host components to cross the plasma membrane of target cells, but characterization of its functional receptors is limited. Here, we discovered that cell-surface glycans, i.e., sialic acid (SA) and heparan sulfate (HS), act as critical interacting factors of PHEV, involving in viral attachment. As shown in glycans depletion assay, removing SA or HS from N2a cells inhibits PHEV infection. Soluble sugar monomers were utilized for competitive binding tests, and we found that both SA and HS could specifically bind to PHEV and affect the viral infectivity. Furthermore, the expression of heparan sulfate proteoglycans (HSPGs), including syndecans and glypicans, and endoglycosidase heparinase which cleaves HS were regulated by PHEV RNA replication. Together, we newly identified specificity recognition of cellular glycans and PHEV during infection, providing novel cellular targets for antiviral therapies and better understanding of pathogenesis.