ABSTRACT
To improve the stability of amino acid ester derivatives of DB02, a series of 24 amide derivatives of DB02 amino acids as non-nucleoside HIV-1 reverse transcriptase inhibitor were designed and synthesized based on bioisosterism by replacing amino acid ester scaffold with more stable amide bond. The anti-HIV-1 activity of these compounds was evaluated by MTT assay and counting the number of syncytia. Most of the target compounds showed a potential anti-HIV-1 activity, among which compounds 2d, 2i, 2l, 2s, and 2w had better antiviral effect than lead compound DB02, with a therapeutic index > 1 000.00. Finally, the structure-activity relationship of these compounds was discussed, which provided new ideas for the further development of DB02 derivatives.
ABSTRACT
Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is the causative agent of the COVID-19 pandemic. The life cycle of SARS-CoV-2 is not clear, which is one of the reasons that only Remdesivir has been approved by FDA for treating COVID-19. Although some new vaccines have been a- vailable, the quick mutations of SARS-CoV-2 affect the effectiveness of vaccines, calling for further assessment of the persistence and safety of vaccines. Therefore, drug treatment and prevention are still effective ways to deal with the epidemic of SARS-CoV-2. The article briefly summarizes the molecular mechanism of SARS-CoV-2 entry based on the existing literature. This virus enters the cell through two main ways, that is, spike protein mediating membrane fusion with plasma membrane or endosome membrane. According to the targets, the article summarizes the reported inhibitors of SARS-CoV-2 entry into cells, aiming to provide a reference for following research and clinical application of anti-SARS-CoV-2 drugs.
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A boy, aged 17 years, was admitted again due to abdominal pain, diarrhea, and eosinophilia for 3 years, which worsened for 3 days. Three years ago, the boy suffered from abdominal pain and diarrhea after eating yogurt; color Doppler ultrasound showed a large amount of peritoneal effusion, and routine blood test, bone marrow cell morphology, and ascites histological examination showed a large number of eosinophils. Three days ago, he was admitted again due to abdominal pain and diarrhea. The gastrointestinal endoscopy showed eosinophil infiltration in the angle of stomach. The boy was diagnosed with eosinophilic gastrointestinal disease (eosinophilic gastroenteritis). He was improved after the treatment with glucocorticoids and dietary avoidance, and no recurrence was observed during the one-year follow-up. It is concluded that for children who attend the hospital due to gastrointestinal symptoms such as abdominal pain and diarrhea, if there is an increase in peripheral blood eosinophils, it is necessary to consider the possibility of eosinophilic gastrointestinal disease, and eosinophil infiltration and abnormal eosinophil count in gastrointestinal tissue based on endoscopic biopsy may be the key to diagnosis.
Subject(s)
Humans , Male , Abdominal Pain/etiology , Ascitic Fluid , Enteritis , Eosinophilia/etiology , GastritisABSTRACT
Dengue virus (DENV) is the most rapidly transmitted mosquito-borne pathogen, which is the main cause of seasonal outbreaks of dengue fever and dengue hemorrhagic fever in tropical and subtropical regions, and may cause serious life-threatening diseases. There is an urgent need to develop effective vaccines or antiviral therapies. In this paper, we found that a podocarpane-type diterpenoid, (3α,5β,10α)-13-methoxypodocarpa-8,11,13-triene-3,12-diol (MPTD), isolated from the stems and leaves of Aleurites moluccana, showed good effect against DENV. The anti-DENV activity of MPTD against four different DENV serotypes was studied by plaque assay. The cytotoxicity of MPTD in Vero and Huh7 cells was tested by MTT assay. qRT-PCR and Western blot assays were used to investigate the anti-DENV activity of MPTD at RNA and protein levels, respectively. The results showed that MPTD greatly reduced the virus titer in DENV infected Vero cells, and its 50% effective concentration (EC50) for DENV (1–4) were 2.72 ± 0.39, 10.99 ± 5.18, 18.72 ± 0.21, and 0.48 ± 0.28 μmol·L-1, respectively. The results showed that MPTD inhibits DENV RNA level and the expression of E protein. In addition, MPTD may inhibit the early stage of DENV replication and exert antiviral activity. Further studies showed that the inhibitory effect of MPTD against DENV infection is not targeting the viral entry stage. Therefore, MPTD has a significant anti-dengue virus effect, and is an anti-DENV compound with potential application value.
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Tenofovir disoproxil fumarate (TDF) is a nucleoside analogue that has been widely used for clinical treatment of human immunodeficiency virus (HIV) and hepatitis B virus (HBV) infection. The aim of this study was to investigate whether TDF has anti-Zika virus (ZIKV) activity in vitro. The inhibitory effect of TDF on ZIKV was detected by plaque reduction assay. Then, the anti-ZIKV activity of TDF at RNA level and protein level was verified by real time quantitative PCR and Western blot. Finally, MTT assay was used to determine the cytotoxicity of TDF. Our results showed that TDF not only reduced the formation of plaque after ZIKV infection, but also inhibited the replication of ZIKV RNA or expression of ZIKV NS2B protein. The 50% effective concentration (EC50) of TDF in inhibition of ZIKV replication were 14.96-27.47 μmol·L-1, while that of ribavirin was 56.01 ± 12.16 μmol·L-1, which served as the positive control. The cytotoxicity of TDF and ribavirin in Vero cells were very low, with their 50% cytotoxic concentration (CC50) values being greater than 500 μmol·L-1. The therapeutic index of TDF calculated by CC50/EC50 was greater than 18.20, which was significantly higher than that of ribavirin. The results suggest that TDF has good anti-ZIKV activity in vitro and is expected to become a candidate drug for anti-ZIKV therapy.
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In this study, azvudine (FNC), hydrochloride salt of azvudine (FNC-HCl) and triphosphate azovudine (FNC-TP) were tested against DENV-Ⅱ recombinant virus (DENV-Ⅱ Luc+). The inhibitory activity of FNC, FNC-HCl and FNC-TP on DENVs were detected by plaque assay. The effect on the expression of DENV-Ⅱ envelope protein E was detected by Western blot; the inhibitory of DENV-Ⅱ viral RNA by compounds was detected by real-time quantitative PCR. MTT assay was used to determine the cytotoxicity of the three compounds on Vero cells. The results showed that FNC, FNC-HCl and FNC-TP inhibited the viral replication by inhibition of renilla luciferase activity of DENV-Ⅱ Luc+. The 50% effective concentration (EC50) of FNC, FNC-HCl and FNC-TP in the inhibition of DENVs replication were from 0.54-25.42 μmol·L-1, while that of ribavirin was 40.78 ±1.02 μmol·L-1 as the positive control. Western blot and real time quantitative PCR results showed that FNC, FNC-HCl and FNC-TP significantly inhibited the expression of DENV-Ⅱ E protein, and the replication of DENV-Ⅱ viral RNA. The 50% cytotoxic concentrations of FNC, FNC-HCl and FNC-TP were all greater than 3 000.00 μmol·L-1. The results suggest that in vitro anti-DENVs activities of FNC, FNC-HCl and FNC-TP are superior to ribavirin, which are expected to become new candidates of anti-DENV drugs.
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The study is aimed to evaluate the anti-HIV-1 effect of chloroquine in combination with antihuman immunodeficiency virus (HIV) drugs, and inhibition of plasmacytoid dendritic cells (pDC) activation and type I interferon (IFN-I) production by Toll-like receptor 7 (TLR7) agonist stimulation. We investigated the anti-HIV-1ⅢB, HIV-1KM018 activity of chloroquine and chloroquine combined with rategrivir (RAL), enfuvirtide (T-20), indinavir (IDV) and efavirenz (EFV) in vitro by luciferase activity assay system and ELISA method for p24 antigen. We measured the effect of chloroquine on the activation of pDC in combination with RAL and IDV, respectively. Quantitative PCR was used to evaluate the activity of chloroquine in combination with RAL and IDV in the upregulation of interferon (IFN)-α and IFN-β. Chloroquine showed less cytotoxicity to C8166, TZM-bl and PBMC cells, and the 50% cytotoxic concentration values were 85.02 ±0.28, 73.67 ±5.10 and 91.84 ±4.10 μmol·L-1, respectively. The anti-HIV-1ⅢB activity of chloroquine combination with RAL, T-20, IDV and EFV were moderate in synergy, strong in synergy, additive and moderate antagonism, respectively. The anti-HIV-1KM018 activity of chloroquine in combination with RAL, IDV were moderate synergy, minor synergy. There was no significant difference between the chloroquine monotherapy and chloroquine combined with RAL, IDV in the down-regulation of pDC activation and IFN-α, IFN-β expression levels. We have found that chloroquine combined with different anti-HIV drugs represent different degrees of synergism, antagonism or additive anti-HIV-1 effect. Chloroquine in combination with RAL and IDV did not have influence on the inhibitory effect of chloroquine on pDC activation and type I interferon secretion induced by TLR7 agonist. The results suggest that chloroquine may be used to enhance the therapeutic activities of anti-HIV medicines.
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<p><b>OBJECTIVE</b>The pathogenesis of mesangial proliferative glomerulonephritis (MsPGN) and mechanisms of glucocorticoid (GC) resistance have not been fully identified. Cytotoxic T-lymphocyte antigen-4 (CTLA-4) is an important inhibitor of T-lymphocyte activation. The objective of the study is to investigate the CTLA-4 expression and apoptosis in lymphocytes of children with MsPGN and the effects of dexamethasone (Dex) on the CTLA-4 expression and apoptosis.</p><p><b>METHODS</b>Blood samples were collected from 36 children with MsPGN and 30 healthy children. CTLA-4 expression in in vitro cultured lymphocytes with or without Dex treatment was measured by flow cytometry following direct immune fluorescene. The rate of apoptosis in the lymphocytes was evaluated by annexin V-FITC and propidium iodide staining.</p><p><b>RESULTS</b>The CTLA-4 expression and apoptosis in lymphocytes from children with MsPGN were significantly lower than those in the healthy control children in the absence or presence of Dex treatment (p<0.05). There was a positive correlation between CTLA-4 expression and apoptosis in lymphocytes (p<0.05).</p><p><b>CONCLUSIONS</b>Abnormal CTLA-4 expression may participate in the pathogenesis of MsPGN and be one of mechanisms of GC resistance.</p>
Subject(s)
Child , Female , Humans , Male , Antigens, CD , Blood , Apoptosis , CTLA-4 Antigen , Dexamethasone , Pharmacology , Glomerulonephritis, Membranoproliferative , Drug Therapy , Lymphocytes , Allergy and ImmunologyABSTRACT
<p><b>BACKGROUND</b>Mesenchymal stem cells are a promising cell type for cell transplantation in myocardial infarction. Type I neuregulins-1, also known as heregulin, can promote the survival of cardiomyocytes and stimulate angiogenesis. The purpose of this study was to investigate the expression of heregulin and ErbB receptors in mesenchymal stem cells, then further detect the secretion of heregulin and the changes in expression of heregulin and ErbB receptors under conditions of serum deprivation and hypoxia.</p><p><b>METHODS</b>Mesenchymal stem cells isolated from bone marrow of 180 g male Sprague-Dawley rats were cultured. Passage 3 cells were detected experimentally by regular reverse transcriptase-polymerase chain reaction (RT-PCR), quantitative real time PCR and Western blotting.</p><p><b>RESULTS</b>Heregulin and ErbB receptors were expressed in mesenchymal stem cells, and all three ErbB receptors mRNA expressions were significantly down-regulated by serum deprivation and hypoxia, but serum deprivation and hypoxia significantly increased the protein expression of heregulin. Serum deprivation and hypoxia more than 12 hours could induce the secretion of heregulin.</p><p><b>CONCLUSIONS</b>Mesenchymal stem cells can express all three ErbB receptors and heregulin. Serum deprivation and hypoxia decrease the mRNA expression of ErbB receptors, increase the expression of heregulin, and activate the secretion of heregulin.</p>
Subject(s)
Animals , Male , Rats , Cell Hypoxia , Cells, Cultured , Mesenchymal Stem Cells , Chemistry , Metabolism , Neuregulin-1 , Genetics , Oncogene Proteins v-erbB , Genetics , RNA, Messenger , Rats, Sprague-DawleyABSTRACT
<p><b>OBJECTIVE</b>Impulse oscillometry (IOS) is a new method for determination of breathing mechanics, which features convenient operation, good repeatability and wider range analysis. As there is no standardized normal value in China at present, this study will provide a normal value of lung function determination by impulse oscillometry for children in Chengdu area.</p><p><b>METHOD</b>Totally 549 children were chosen at random from Chengdu area, with 292 boys and 257 girls who were 4 to 14 years old. The subjects were assigned into 10 age groups according to their chronological age with one year difference between every two adjacent groups. The respiratory total impedance (Zrs), viscosity resistance (Rrs) and elastic resistance (Xrs) at various oscillation frequency were measured by the Master Screen IOS which was manufactured by German Jaeger Company. The measured data were treated with the linear stepwise multiple regression, and established the prediction equation. At the same time, paired comparison was carried out with the measured data and equation obtained from this study, Lechtenboerger equation and prediction equation obtained from Guangzhou area.</p><p><b>RESULT</b>The total impedance and airway resistance were negatively correlated with the children's height and age. Zrs (male) = -0.756 + 189.586/height, r = -0.782, P < 0.001; Zrs (female) = -0.497 + 152.468/height, r = -0.726, P < 0.001. Rrs became the same in trend; while Xrs were proportional to the height, e.g. the values increased as the height increased. The difference of the airway resistance (R(5)-R(20)) was negatively correlated with the children's height: R(5)-R(20) (male) = 0.601 - 0.0034 x height, r = -0.677, P < 0.001; R(5)-R(20) (female) = 0.549 - 0.0031 x height, r = -0.658, P < 0.001. Among the relationships with many impulse oscillometry parameters, height ranked at first place; age at second. The multiple regression equation of IOS primary index was established. Both the measured data and the correlation coefficient of the study obtained equation were greater than the coefficient correlation of the Lechtenboerger equation, but had no significant difference compared with that of prediction equation in Guangzhou area.</p><p><b>CONCLUSION</b>The normal value in impulse oscillometry in children in Chengdu area is different from the predicted parameters in other countries. The equation obtained from this study seems to be more suitable for the children in its local area. It is recommended to apply the predicted value from the corresponding population in the determination of the lung function by impulse oscillometry.</p>
Subject(s)
Child , Female , Humans , Male , Airway Resistance , Physiology , China , Electric Impedance , Oscillometry , Methods , Respiratory Function Tests , Methods , Respiratory Physiological PhenomenaABSTRACT
<p><b>OBJECTIVE</b>This study was performed to evaluate whether implantation of mesenchymal stem cell (MSC) would reduce left ventricular remodelling from the molecular mechanisms compared with angiotensin-converting enzyme inhibitors (ACEIs) perindopril into ischemic myocardium after acute myocardial infarction.</p><p><b>METHODS</b>Forty rats were divided into four groups: control, MSC, ACEI, MSC+ACEI groups. Bone marrow stem cell derived rat was injected immediately into a zone made ischemic by coronary artery ligation in MSC group and MSC+ACEI group. Phosphate-buffered saline (PBS) was injected into control group. Perindopril was administered p.o. to ACEI group and MSC+ACEI group. Six weeks after implantation, the rats were killed and heart sample was collected. Fibrillar collagen was observed by meliorative Masson's trichome stain. Western Blotting was employed to evaluate the protein expression of matrix metalloproteinase (MMP)-2, matrix metalloproteinase (MMP)-9 in infarction zone. The transcriptional level of MMP2, MMP9 and tissue inhibitor of matrix metalloproteinase (TIMP)-1 in infarction area was detected by reverse transcriptase PCR (RT-PCR) analysis.</p><p><b>RESULTS</b>The fibrillar collagen area, the protein expression of MMP2, MMP9 and the transcriptional level of MMP2, MMP9 mRNA in infarction zone reduced in MSC group, ACEI group, and MSC+ACEI group. No significant difference was detected in the expression of TIMP1 mRNA among the 4 groups.</p><p><b>CONCLUSION</b>Both MSC and ACEI could reduce infarction remodelling by altering collagen metabolism.</p>
Subject(s)
Animals , Male , Rats , Angiotensin-Converting Enzyme Inhibitors , Therapeutic Uses , Bone Marrow Cells , Cell Biology , Matrix Metalloproteinase 2 , Matrix Metalloproteinase 9 , Mesenchymal Stem Cell Transplantation , Myocardial Infarction , Pathology , Therapeutics , Myocardium , Perindopril , Therapeutic Uses , Rats, Sprague-Dawley , Tissue Inhibitor of Metalloproteinase-1 , Ventricular RemodelingABSTRACT
<p><b>OBJECTIVE</b>Recent experimental and clinical observations have suggested that cell transplantation could be of therapeutic value for the treatment of heart failure. This study was performed to explore the efficacy and safety of intracoronary autologous mesenchymal stem cells (MSCs) transplantation for treating patients with idiopathic dilated cardiomyopathy.</p><p><b>METHOD</b>Twenty-four consecutive patients with idiopathic dilated cardiomyopathy received standard drug therapy were randomly divided into intracoronary injection of autologous mesenchymal stem cells (treated, n = 12) or saline (control, n = 12) groups. Serum IL-6, TNF-alpha and CRP, plasma brain natriuretic peptides (BNP) were determined and echocardiography, Holter electrocardiogram monitoring and six minutes walk test were performed at baseline, 3 and 6 months post injection.</p><p><b>RESULTS</b>IL-6, TNF-alpha and CRP remained unchanged after MSCs transplantation. Plasma BNP levels at 3 months and 6 months post MSCs injection were significantly higher than that of pre-injection (378.10 +/- 147.47, 420.40 +/- 148.50 vs. 292.40 +/- 148.54 ng/L, respectively, P < 0.05) but were significantly lower than that in control group at comparable time points (3 months: 378.10 +/- 147.47 vs. 473.10 +/- 106.31 ng/L; 6 months: 420.40 +/- 148.50 vs. 544.60 +/- 93.11 ng/L, P < 0.05). Six-minute-walking distance significantly increased at 6 months after MSCs injection compared with pre-injection level and which is also higher than that in control patients (519.00 +/- 43.28 vs. 396.33 +/- 42.19 and 464.00 +/- 76.5 m, respectively, P < 0.05). Left ventricular ejection fraction and LVEDd remained unchanged post MSCs injection. No malignant arrhythmias and severe side effects could be observed around transplantation and during six months follow-up. Survival was similar between the two groups during six months follow-up.</p><p><b>CONCLUSION</b>Percutaneous coronary autologous mesenchymal stem cells transplantation can attenuate the increase of plasma BNP, increase six-minute-walking capacity in patients with idiopathic dilated cardiomyopathy.</p>