Brain-derived neurotrophic factor (BDNF) shows potential in the treatment of neurodegenerative diseases, but the therapeutic application of BDNF has been greatly limited because it is too large in molecular size to permeate blood-brain barrier. To develop low-molecular-weight BDNF-like peptides, we selected a phage-displayed random peptide library using trkB expressed on NIH 3T3 cells as target in the study. With the strategy of peptide library incubation with NIH 3T3 cells and competitive elution with 1 μg/mL of BDNF in the last round of selection, the specific phages able to bind to the natural conformation of trkB and antagonize BDNF binding to trkB were enriched effectively. Five trkB-binding peptides were obtained, in which a core sequence of CRA/TXΦXXΦXXC (X represents the random amino acids, Φ represents T, L or I) was identified. The BDNF-like activity of these five peptides displayed on phages was not observed, though all of them antagonized the activity of BDNF in a dose-dependent manner. Similar results were obtained with the synthetic peptide of C1 clone, indicating that the 5 phage-derived peptides were trkB antagonists. These low-molecular-weight antagonists of trkB may be of potential application in the treatment of neuroblastoma and chronic pain. Meanwhile, the obtained core sequence also could be used as the base to construct the secondary phage-displayed peptide library for further development of small peptides mimicking BDNF activity. 相似文献
A rapid, sensitive and selective ultra-performance liquid chromatography–tandem mass spectrometry (UPLC–MS/MS) method with hydrophilic interaction chromatography has been developed and validated for the simultaneous determination of didanosine and valdidanosine (L-valine amino acid ester prodrug of didanosine) in rat plasma. Solid-phase extraction (SPE) column was employed to extract the analytes from rat plasma, with high extraction recovery (>85%) for both didanosine and valdidanosine. The analytes were then separated by hydrophilic interaction chromatography (HILIC column) and detected by a triple-quadrupole mass spectrometry equipped with an electrospray ionization (ESI) source. The method was linear over the concentration ranges of 2–20,000 ng/mL for didanosine and 4–300 ng/mL for valdidanosine. The lower limit of quantitation (LLOQ) of didanosine and valdidanosine was 2 and 4 ng/mL, respectively. The intra-day and inter-day relative standard deviation (RSD) were less than 15% and the relative errors (RE) were all within 15%. Finally, the validated UPLC–MS/MS method was successfully applied to the pharmacokinetic study after either didanosine or valdidanosine orally administrated to the Sprague–Dawley rats. 相似文献
Hepatitis C (HCV) genome is highly variable, particularly in the hypervariable region 1 (HVR1) of its E2 envelope gene. The
variability of HCV genome has been a major obstacle for developing HCV vaccines. Due to B-cell HVR1 mimotopes mimicking the
antigenicity of natural HVR1 epitopes and some T-cell epitopes from the consensus sequence of HCV genes conserving among the
different HCV genotypes, we synthesized an minigene of HCV-derived multi-epitope peptide antigen (CMEP), which contains 9
B-cell HVR1 mimotopes in E2, 2 conserved CTL epitopes in C, 1 conserved CTL epitope in NS3 and 1 conserved Th epitope in NS3.
This minigene was cloned into a GST expression vector to generate a fusion protein GST-CMEP. The immunogenic properties of
CEMP were characterized by HCV infected patients’ sera, and found that the reactivity frequency reached 75%. The cross reactivity
of anti-CEMP antibody with different natural HVR1 variants was up to 90%. Meanwhile, we constructed an HCV DNA vaccine candidate,
plasmid pVAX1.0-st-CMEP carrying the recombinant gene (st) of a secretion signal peptide and PADRE universal Th cell epitope sequence in front of the CMEP minigene. Immunization of
rabbits with pVAX1.0-st-CMEP resulted in the production of antibody, which was of the same cross reactivity as the fusion protein GST-CMEP. Our findings
indicate that the HCV-derived multi-epitope peptide antigen in some degree possessed the characteristics of neutralizing HCV
epitopes, and would be of the value as a candidate for the development of HCV vaccines. 相似文献
The coronavirus disease 2019 (COVID-19) pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a global crisis. Clinical candidates with high efficacy, ready availability, and that do not develop resistance are in urgent need. Despite that screening to repurpose clinically approved drugs has provided a variety of hits shown to be effective against SARS-CoV-2 infection in cell culture, there are few confirmed antiviral candidates in vivo. In this study, 94 compounds showing high antiviral activity against SARS-CoV-2 in Vero E6 cells were identified from 2,580 FDA-approved small-molecule drugs. Among them, 24 compounds with low cytotoxicity were selected, and of these, 17 compounds also effectively suppressed SARS-CoV-2 infection in HeLa cells transduced with human ACE2. Six compounds disturb multiple processes of the SARS-CoV-2 life cycle. Their prophylactic efficacies were determined in vivo using Syrian hamsters challenged with SARS-CoV-2 infection. Seven compounds reduced weight loss and promoted weight regain of hamsters infected not only with the original strain but also the D614G variant. Except for cisatracurium, six compounds reduced hamster pulmonary viral load, and IL-6 and TNF-α mRNA when assayed at 4 d postinfection. In particular, sertraline, salinomycin, and gilteritinib showed similar protective effects as remdesivir in vivo and did not induce antiviral drug resistance after 10 serial passages of SARS-CoV-2 in vitro, suggesting promising application for COVID-19 treatment.
Bacterial endotoxin lipopolysaccharide (LPS) often results in multiple organ failure.However,pre-exposure of mice to a sublethal dose of LPS renders the animal tolerant to a lethal dose of LPS.Thisstudy was designed to determine whether pre-exposure of a small dose of LPS was able to suppressapoptosis in mice when challenged with LPS in combination with D-galactosamine,and to investigate theexpression changes of the apoptosis-associated molecules.The results showed that a characteristic apoptoticDNA fragmentation existed in mouse livers of the LPS-naive group,but not in control groups;and the miceof the LPS-naive group were all dead after 2 d.However,in the LPS-tolerance groups,both the lethal rateand apoptotic DNA fragmentation were suppressed after the mice were challenged with LPS/D-galactosamine,and the protection against the lethality and apoptotic reaction could be maintained for up to 7 d.In thisperiod, significantly lower levels of caspase-3 and its mRNA appeared in LPS-tolerant groups compared tothose of the LPS-naive group (P<0.05),and the caspase-3 activities gradually recovered as the observationwas prolonged.Our findings suggest that LPS tolerance could suppress apoptosis in mouse liver cells,andthe expression and activity of caspase-3 could be down-regulated. 相似文献
Streptococcus pneumoniae (S. pneumoniae) is a major causative agent of respiratory disease in patients and can cause respiratory distress and other symptoms in severe cases. Pneumolysin (PLY) is a pore-forming toxin that induces host tissue injury and inflammatory responses. Sortase A (SrtA), a catalytic enzyme that anchors surface-associated virulence factors, is critical for S. pneumoniae virulence. Here, we found that the active ingredient of the Chinese herb Scutellaria baicalensis, wogonin, simultaneously inhibited the haemolytic activity of PLY and SrtA activity. Consequently, wogonin decreased PLY-mediated cell damage and reduced SrtA-mediated biofilm formation by S. pneumoniae. Furthermore, our data indicated that wogonin did not affect PLY expression but directly altered its oligomerization, leading to reduced activity. Furthermore, the analysis of a mouse pneumonia model further revealed that wogonin reduced mortality in mice infected with S. pneumoniae laboratory strain D39 and S. pneumoniae clinical isolate E1, reduced the number of colony-forming units in infected mice and decreased the W/D ratio and levels of the inflammatory factors TNF-α, IL-6 and IL-1β in the lungs of infected mice. Thus, wogonin reduces S. pneumoniae pathogenicity by inhibiting the dual targets PLY and SrtA, providing a treatment option for S. pneumoniae infection.相似文献