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1.
EBioMedicine ; 51: 102610, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31918403

RESUMO

In most cases, sorafenib-resistant HCC cells exhibit significant mesenchymal phenotype and stemness features. In this context, tumor cells might undergo cell fate transition in response to sorafenib or other targeted drugs in the presence or absence of genetic mutations. Therefore, understanding the major characteristics of drug-resistant cells state helps to discover new treatments that overcome drug resistance. To note, little is known about the metabolic or microenvironmental aspects of the certain tumor cell states beyond the genome. This review mainly focuses on the underlying mechanisms of acquired sorafenib resistance based on CSCs and EMT models, which explain tumor heterogeneity and have been considered the major cause of secondary sorafenib resistance. In particular, it discusses how the tumor microenvironment and tumor metabolism regulate cell stemness, mesenchymal state, and sorafenib resistance through epigenetic regulations, and provides reliable targets that might have synergetic effect with sorafenib.

2.
Eur J Med Chem ; 188: 112027, 2020 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-31923859

RESUMO

Genetic rearrangements of the mixed lineage leukemia (MLL) leading to oncogenic MLL-fusion proteins (MLL-FPs). MLL-FPs occur in about 10% of acute leukemias and are associated with dismal prognosis and treatment outcomes which emphasized the need for new therapeutic strategies. In present study, by a cell-based screening in-house compound collection, we disclosed that Rabeprazole specially inhibited the proliferation of leukemia cells harboring MLL-FPs with little toxicity to non-MLL cells. Mechanism study showed Rabeprazole down-regulated the transcription of MLL-FPs related Hox and Meis1 genes and effectively inhibited MLL1 H3K4 methyltransferase (HMT) activity in MV4-11 cells bearing MLL-AF4 fusion protein. Displacement of MLL1 probe from WDR5 protein suggested that Rabeprazole may inhibit MLL1 HMT activity through disturbing MLL1-WDR5 protein-protein interaction. Moreover, other proton pump inhibitors (PPIs) also indicated the inhibition activity of MLL1-WDR5. Preliminary SARs showed the structural characteristics of PPIs were also essential for the activities of MLL1-WDR5 inhibition. Our results indicated the drug reposition of PPIs for MLL-rearranged leukemias and provided new insight for further optimization of targeting MLL1 methyltransferase activity, the MLL1-WDR5 interaction or WDR5.

3.
Biologicals ; 63: 68-73, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31899075

RESUMO

Platelet-derived growth factors (PDGFs) are involved in various physiological and pathological processes, making them important targets for drug development. However, current methods for measuring PDGF bioactivity do not meet the rapidly growing requirements of pharmaceutical research. Here, we describe a novel reporter gene assay (RGA) for PDGF-BB activity measurement. RGA was developed with engineered cells expressing a modified luciferase protein under the control of an SRE element. With PDGF-BB stimulation, cells produced stable dose-dependent signals with a correlation coefficient of R2 > 0.97 within several hours. The relative accuracy of the assay, represented by the relative bias for five independent samples with different bioactivity levels, was less than 4.67%. Variations in RGA caused by intra- and inter-assay factors were smaller than 10% and 15%, respectively. RGA not only yielded consistent results for estimating PDGF-BB activity, but also presented significantly lower variations than did the traditional colorimetric assay. Moreover, RGA could be completed within 2 days, showing a much higher efficiency than the WST method, which requires 4-5 days. Furthermore, RGA is suitable for other PDGF species besides PDGF-BB. Our results demonstrate that RGA could be a powerful tool for screening and identifying PDGF-related drug candidates in pharmaceutical applications.

4.
Adv Mater ; 32(4): e1905896, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31825536

RESUMO

2D magnetic materials have attracted intense attention as ideal platforms for constructing multifunctional electronic and spintronic devices. However, most of the reported 2D magnetic materials are mainly achieved by the mechanical exfoliation route. The direct synthesis of such materials is still rarely reported, especially toward thickness-controlled synthesis down to the 2D limit. Herein, the thickness-tunable synthesis of nanothick rhombohedral Cr2 S3 flakes (from ≈1.9 nm to tens of nanometers) on a chemically inert mica substrate via a facile chemical vapor deposition route is demonstrated. This is accomplished by an accurate control of the feeding rate of the Cr precursor and the growth temperature. Furthermore, it is revealed that the conduction behavior of the nanothick Cr2 S3 is variable with increasing thickness (from 2.6 to 4.8 nm and >7 nm) from p-type to ambipolar and then to n-type. Hereby, this work can shed light on the scalable synthesis, transport, and magnetic properties explorations of 2D magnetic materials.

5.
Anal Chem ; 92(1): 1114-1121, 2020 Jan 07.
Artigo em Inglês | MEDLINE | ID: mdl-31763820

RESUMO

Bacterial magnetic particles (BMPs) are an attractive carrier material for immunoassays because of their nanoscale size, dispersal ability, and membrane-bound structure. Antitetrabromobisphenol-A (TBBPA) nanobodies (Nbs) in the form of monovalence (Nb1), bivalence (Nb2), and trivalence (Nb3) were biotinylated and immobilized onto streptavidin (SA)-derivatized BMPs to construct the complexes of BMP-SA-Biotin-Nb1, -Nb2, and -Nb3, respectively. An increasing order of binding capability of BMP-SA-Biotin-Nb1, -Nb2, and -Nb3 to TBBPA was observed. These complexes showed high resilience to temperature (90 °C), methanol (100%), high pH (12), and strong ionic strength (1.37 M NaCl). A BMP-SA-Biotin-Nb3-based enzyme linked immunosorbent assay (ELISA) for TBBPA dissolved in methanol was developed, showing a half-maximum inhibition concentration (IC50) of 0.42 ng mL-1. TBBPA residues in landfill leachate, sewage, and sludge samples determined by this assay were in a range of

6.
J Membr Biol ; 253(1): 43-55, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31820013

RESUMO

Lysophosphatidylcholine (LPC) is a major atherogenic lipid that stimulates an increase in mitochondrial reactive oxygen species (mtROS) and the release of cytokines under inflammasome activation. However, the potential receptors of LPC in macrophages are poorly understood. Members of the transient receptor potential (TRP) channel superfamily, which is crucially involved in transducing environmental irritant stimuli into nociceptor activity, are potential receptors of LPC. In this study, we investigated whether LPC can induce the activation of transient receptor potential ankyrin 1 (TRPA1), a member of the TRP superfamily. The functional expression of TRPA1 was first detected by quantitative real-time polymerase chain reaction (qRT-PCR), western blotting and calcium imaging in human acute monocytic leukemia cell line (THP-1)-derived macrophages. The mechanism by which LPC induces the activation of macrophages through TRPA1 was verified by cytoplasmic and mitochondrial calcium imaging, mtROS detection, a JC-1 assay, enzyme-linked immunosorbent assay, the CCK-8 assay and the lactate dehydrogenase (LDH) cytotoxic assay. LPC induced the activation of THP-1-derived macrophages via calcium influx, and this activation was suppressed by potent and selective inhibitors of TRPA1. These results indicated that TRPA1 can mediate mtROS generation, mitochondrial membrane depolarization, the secretion of IL-1ß and cytotoxicity through cellular and mitochondrial Ca2+ influx in LPC-treated THP-1-derived macrophages. Therefore, the inhibition of TRPA1 may protect THP-1-derived macrophages against LPC-induced injury.

7.
Cytokine ; 125: 154801, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31442680

RESUMO

BACKGROUND: HIV rapid progressors (RPs) present with a rapid decline of CD4+ T cells within a few years of infection. Determining the underlying mechanisms throughout this decline is important to identify prognostic biomarkers and intervention strategies. Determining the numbers of CD4+ and CD8+ T cells is essential for monitoring the immune status of HIV infected patients. There are additional kinds of cell subtypes in T cells, but their relationship to the rapid progression of HIV disease is not well defined. METHODS: Nineteen RPs and twenty-one chronic progressors (CPs) were enrolled in this study. Based on the intensity of CD4 and CD8 expression, different T cell subtypes were identified, including CD4+CD8+T cells, CD4-CD8- T cells, CD4+CD8low T cells and CD4-CD8low T cells. Alterations in these T cell subtypes in early HIV infection (within 120 days of infection) between RPs and CPs were measured, and the relationships between these subtypes and HIV disease progression were investigated. In addition, expression of IFN-γ in T cell subtypes after PMA stimulation was analyzed by flow cytometry. RESULTS: We found that during early HIV infection, CD4+CD8low T cells both significantly decreased in numbers and percentages in RPs compared to CPs. Furthermore, baseline CD4+CD8low T cells positively correlated not only with baseline CD4+T cells but also with CD4+T cells 12 months after infection. Moreover, survival analysis indicated that low levels of baseline CD4+CD8low T cells significantly accelerated the decline in CD4+ T cells as well as increased viral loads. CD4+CD8low T cells secreted significantly more IFN-γ after PMA stimulation compared to CD4+CD8-T cells and CD4-CD8+T cells, which may be beneficial for the prevention of disease progression. CONCLUSIONS: Our results identified that in early stage HIV-1 infection, a subtype of T cells, CD4+CD8low, are associated with subsequent disease progression.

8.
Hum Vaccin Immunother ; : 1-9, 2019 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-31809637

RESUMO

Polysaccharides isolated from natural plants may represent a novel source of vaccine adjuvants. In this research, we focused on a natural plant polysaccharide, PCP-I, which is derived from Poria cocos, a Chinese traditional herbal medicine. We chose the anthrax protective antigen (PA) as a model to evaluate the adjuvant ability of PCP-I in enhancing the immunogenicity and protection of a PA-based anthrax vaccine. According to our results, PCP-I could significantly enhance anthrax specific anti-PA antibodies, toxin-neutralizing antibodies, anti-PA antibody affinity, as well as IgG1 and IgG2a levels. Besides, PCP-I increased the frequency of PA-specific memory B cells, increased the proliferation of PA-specific splenocytes, significantly stimulated the secretion of IL-4, and enhanced the activation of Dendritic cells (DCs) in vitro. The combination of PCP-I and CpG significantly enhanced the level of anti-PA antibodies and neutralizing antibodies, particularly PA-specific IgG2a, and shifted the Th2-bias to a Th1/Th2 balanced response. In addition, PCP-I with or without CpG could significantly improve the survival rate of immunized mice following challenge with the anthrax lethal toxin. These findings suggest that PCP-I may be a promising vaccine adjuvant that warrants further study.

9.
J Transl Med ; 17(1): 417, 2019 Dec 13.
Artigo em Inglês | MEDLINE | ID: mdl-31836011

RESUMO

BACKGROUND: Chemokines are small chemotactic cytokines involved in inflammation, cell migration, and immune regulation in both physiological and pathological contexts. Here, we investigated the profile of chemokines during primary HIV infection (PHI). METHODS: Fifty-four participants with blood samples before and during HIV infection and clinical information available were selected from an HIV-negative man who have sex with men (MSM) prospective cohort. Thirty chemokines and 10 cytokines were measured pre- and post-HIV infection in the same individuals using a Bio-Plex Pro™ Human Chemokine Panel. RESULTS: Levels of 18 chemokines/cytokines changed significantly during PHI relative to pre-HIV infection levels; 14 were up-regulated and 4 down-regulated. Among them, CXCL9, CXCL10, and CXCL11 were the most prominently raised. Levels of CXCL9 and CXCL10 were much higher in the high-set point group (log viral load (lgVL) ≥ 4.5) than those in the low-set point group (lgVL < 4.5) and levels of CXCL9, CXCL10, and CXCL11 were higher in the low-CD4+ T-cell count group (CD4+ T-cell count ≥ 500). A formula to predict HIV disease progression using a combination panel comprising CXCL9, CXCL10, and CXCL11 was developed, where risk score = 0.007 × CXCL9 + 0.004 × CXCL10 - 0.033 × CXCL11 - 1.724, with risk score values higher than the cutoff threshold (0.5211) indicating more rapid HIV disease progression. CONCLUSIONS: A panel of plasma CXCL9, CXCL10, and CXCL11 measured during primary HIV-1 infection could predict long-term HIV disease prognosis in an MSM group and has potential as a novel biomarker in the clinic.

10.
Gastric Cancer ; 2019 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-31853750

RESUMO

BACKGROUND: Epigenetic aberrations of tumor suppressor genes (TSGs), particularly DNA methylation, are frequently involved in the pathogenesis of gastric cancer (GC). Through a methylome study, we identified eIF4EBP3 as a methylated gene in GC. However, the role of eIF4EBP3 in GC progression has not been explored. METHODS: The expression and promoter region methylation of eIF4EBP3 in GC and healthy tissues were analyzed in public datasets. eIF4EBP3 expression in GC was detected by semi-quantitative RT-PCR, western blot and immunohistochemistry. We also studied epigenetic alterations and functions in GC. The effects of eIF4EBP3 on cell proliferation, migration and invasion were conducted by functional experiments in vitro and in vivo. Label-free proteomic analysis was applied to identify targets of eIF4EBP3. RESULTS: The expression level of eIF4EBP3 was downregulated in gastric cancer due to promoter region methylation, and was associated with poor survival and tumor progression. Ectopic expression of eIF4EBP3 significantly inhibited tumor cell growth, migration and invasion both in vitro and in vivo. Label-free proteomic analysis indicated eIF4EBP3 downregulated the protein level of ß-catenin, which was confirmed by western blot. Overexpression of ß-catenin reversed the inhibitory effects of eIF4EBP3 on cell growth and migration, indicating that eIF4EBP3 acts on GC cells by targeting the eIF4E/ß-catenin axis. CONCLUSION: These results suggest that eIF4EBP3 is a novel TSG methylated in gastric cancer that may play important roles in GC development and liver metastasis and indicate eIF4EBP3 as a potential metastasis and survival biomarker for GC.

11.
Artigo em Inglês | MEDLINE | ID: mdl-31781514

RESUMO

Introduction: Helicobacter pylori infection consistently leads to chronic and low degree of inflammatory response in gastric mucosa and is closely related with gastrointestinal and extra-gastric diseases. Effects of local microbiome in the stomach have been studied in adults and children with H. pylori infection. It is, however, not known whether the intestinal microbial community differs in children with varying H. pylori infection. The aim of this study is to characterize the altered composition of microbiome induced by H. pylori infection and in gastritis. Materials and Methods: This study involved 154 individuals, including 50 children affected by H. pylori-induced gastritis, 42 children with H. pylori-negative gastritis, and 62 healthy controls. Gut microbiome composition was analyzed using 16S rRNA gene-based pyrosequencing. Fecal bacterial diversity and composition were then compared. Results: On the basis of an analysis of similarities and differences, we found that children with H. pylori-induced gastritis exhibited gut bacteria dysbiosis. The ratio of Firmicutes/Bacteroidetes (F:B) at the phylum level had dramatically decreased in H. pylori-positive gastritis group (HPG) and H. pylori-negative gastritis group (HNG), compared with the healthy control group (HCG). At the family and genus levels, relative abundance of Bacteroidaceae and Enterobacteriaceae was prevalent in HPG and HNG, whereas relative abundance of Lachnospiraceae, Bifidobacteriaceae, and Lactobacillaceae was seen in HCG. Prevalence of different taxa of gut microbiome at the class, order, family, and genus levels was also observed among the three groups. Conclusions: Gastritis can cause changes in composition of fecal microbiome, which is exacerbated by H. pylori infection. These changes in gut microbiome may be related to drug resistance and development of chronic gastrointestinal diseases.

13.
J Neurochem ; 2019 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-31603990

RESUMO

Cystatin C, a well-established biomarker of renal function, has been associated with a protective effect against stroke. However, the potential neuroprotective mechanism of cystatin C in ischemic brain injury remains unclear. Our study hypothesized that cystatin C can ameliorate blood-brain barrier (BBB) disruption by up-regulating caveolin-1 expression, thereby improving neurological outcomes in cerebral ischemic injury. Western blotting, immunohistochemistry, immunofluorescence staining, and immunoprecipitation were performed to investigate target proteins. Evans Blue and gelatin zymography were used to examine the effect of cystatin C on BBB disruption. Plasmid and small interfering RNA transfection was used to observe alterations in caveolin-1 and occludin expression induced by changes in cystatin C expression. Intriguingly, our study showed that the expression of both cystatin C and caveolin-1 was increased in middle cerebral artery occlusion-injured mice, and pretreatment with exogenous cystatin C significantly increased caveolin-1 expression, reduced Evans Blue leakage in the injured brain region, and decreased the enzymatic activity of matrix metallopeptidase-9. Meanwhile, our study also showed that the over-expression of cystatin C greatly enhanced caveolin-1 expression, which later increased occludin expression in oxygen-glucose deprivation-exposed brain microvascular endothelial cells. The knockdown of cystatin C induced the opposite outcomes. These experimental results indicate a positive role for cystatin C in the regulation of caveolin-1 and occludin expression in cerebral ischemic injury. Taken together, these data unveil a new mechanism of the regulation of caveolin-1 expression by cystatin C in the maintenance of BBB integrity after ischemic brain injury and provide new clues for the identification of potential therapeutic strategies for stroke.

14.
Transfusion ; 59(11): 3431-3441, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31532001

RESUMO

BACKGROUND: Understanding the latest human immunodeficiency virus (HIV) epidemic in voluntary blood donors could be of great value to further increase blood safety in China, as transfusion-transmitted infection places a heavy burden on both infected individuals and the whole society. Therefore, we evaluated the national HIV prevalence of voluntary blood donors in China and characteristics of HIV-infected blood donors. STUDY DESIGN AND METHODS: We searched literature in Chinese and English concerning the prevalence of HIV infections in Chinese voluntary blood donors from 2010 to 2017, yielding 97 eligible papers. We performed a meta-analysis to calculate pooled HIV prevalence, and characteristics of HIV-infected blood donors were also extracted. RESULTS: The pooled sample consisted of 21,100,755 voluntary blood donors and 4,755 HIV-infected blood donors. Pooled HIV prevalence of China voluntary blood donors during 2010 to 2017 was 21.02 in 100,000. Pooled HIV prevalence varied in different provinces, showing greater severity in Southwest, Northwest, and South China. Subgroup analysis also showed a significantly increasing trend from 2010 to 2017. The majority of HIV-infected blood donors in China were male, young, unmarried, nonlocal residents, receiving 12 years or less of schooling, and first-time donors. Nearly 90% of HIV-infected blood donors acquired their infections through sexual contact. CONCLUSION: The prevalence of HIV increased in China among voluntary blood donors during 2010 to 2017, highlighting the risk of HIV transmission by transfusion. Blood centers and public health services should improve screening and intervention programs targeting voluntary blood donors and expand education on blood safety in areas experiencing severe epidemics and among high-risk populations.

15.
J Leukoc Biol ; 106(6): 1313-1323, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31483071

RESUMO

The percentage of human CD56- CD16+ NK cells increases during chronic infection with human HIV; however, the biologic role of CD56- CD16+ NK cells in HIV infection is unclear. Our results demonstrate that the percentage of CD56- CD16+ NK cells producing IL-10 and TGF-ß was higher than CD56dim CD16+ NK cells. CD56- CD16+ NK cells could inhibit IFN-γ production by autologous CD8+ T cells, and this inhibition could be partially reversed by anti-IL-10, anti-TGF-ß, or anti-PD-L1 mAbs. CD56- CD16+ NK cells are potential targets for the development of novel immune therapies against HIV infection.

16.
Lancet HIV ; 2019 Aug 28.
Artigo em Inglês | MEDLINE | ID: mdl-31473165
17.
Endocr Connect ; 2019 Aug 01.
Artigo em Inglês | MEDLINE | ID: mdl-31398710

RESUMO

PURPOSE: Gallbladder neuroendocrine neoplasm (GB-NEN) is a relatively rare neoplasm, accounting for 0.5% of all neuroendocrine neoplasm cases and 2.1% of gallbladder cancers. Because of the limited understanding of GB-NEN, the aim of this study was to explore the clinicopathology and survival of GB-NEN patients selected from the Surveillance, Epidemiology, and End Results (SEER) database. METHODS: A total of 248 GB-NEN patients from the SEER database diagnosed between 2004 and 2015 were included. Kaplan-Meier curves were used to examine survival outcomes. Multivariate Cox proportional hazard models were used to estimate hazard ratios with 95% confidence intervals to analyze the impact of factors on overall survival and cancer-specific survival. RESULTS: The majority of the GB-NEN patients were women (67.3%), white (77%), and married (61.7%). Most tumors were <2 cm in size (31.0%), G3 stage (25.8%), and distant SEER stage (41.1%). Lots of cases showed an absence of lymph node metastasis and tumor metastasis. Patients who received gallbladder surgery had significantly better survival outcomes (p<0.001), but patients who received both gallbladder and lymph node surgery did not have better survival outcome compared with patients receiving only gallbladder surgery. Multivariate Cox proportional hazard models indicated age, marital status, tumor size, and SEER stage were significant independent predictors for overall survival and cancer-specific survival (p<0.05). CONCLUSION: Age, marital status, tumor size, and SEER stage were predictors for the survival of GB-NEN patients. Gallbladder surgery was associated with better survival, but the combination of gallbladder surgery and lymphadenectomy had no effect on survival outcomes.

18.
BMC Infect Dis ; 19(1): 721, 2019 Aug 15.
Artigo em Inglês | MEDLINE | ID: mdl-31416439

RESUMO

BACKGROUND: Pre-exposure prophylaxis (PrEP) is a promising and effective tool to prevent human immunodeficiency virus (HIV) transmission; however, context-specific data to guide optimal implementation are currently lacking in China. This study aims to systematically collect comprehensive, empirical data to determine effective ways to implement PrEP among at-risk men who have sex with men (MSM) in China. METHODS: The CROPrEP project, a real-world study of PrEP use, will recruit 1000 high-risk HIV-negative MSM participants from four cities in China, who will be able to choose between daily or event-driven dosing regimens, according to their preference. Participants will be followed up at months 1, 3, 6, 9, and 12 for PrEP provision, clinical evaluation, laboratory testing (e.g., emtricitabine/tenofovir disoproxil fumarate (FTC/TDF) concentrations, and HIV/sexually transmitted infections), alongside detailed, self-administered online questionnaires regarding sexual behaviors, adherence, and attitudes. Online weekly notes will be used to record pill use and sexual practice. Various measurements will be triangulated to assess adherence, including: self-reported adherence, pill count, and drug concentration. A propensity score matching model will be fitted to examine the effectiveness of PrEP use in HIV seroconversion compared with non-PrEP users selected from a local expanding cohort study of HIV-1-negative MSM at participating research centers. Analyses using a generalized estimating equation model will focus on elucidation of the cascade of PrEP implementation, effectiveness, safety, and possible effects of PrEP use on sexual behaviors. This study will provide a comprehensive assessment of real-world PrEP use among Chinese MSM, to develop guidelines and strategies for PrEP implementation in China. DISCUSSION: The CROPrEP project is the first study of the TDF/FTC combination as PrEP in China, which will provide primary data on PrEP implementation, including: the cascade of PrEP use, "real-world" effectiveness, adherence, and safety. The findings from this study have potential to be vital for promoting the integration of PrEP within the portfolio of HIV prevention interventions and developing guidance on PrEP implementation in China. TRIAL REGISTRATION: ChiCTR-IIN-17013762 (Chinese Clinical Trial Registry). Date of registration: 8 December 2017.


Assuntos
Fármacos Anti-HIV/uso terapêutico , Infecções por HIV/prevenção & controle , Homossexualidade Masculina , Profilaxia Pré-Exposição/métodos , Adulto , China , Estudos de Coortes , Emtricitabina/uso terapêutico , Infecções por HIV/tratamento farmacológico , Humanos , Masculino , Estudos Multicêntricos como Assunto , Sexo Seguro , Autorrelato , Comportamento Sexual/estatística & dados numéricos , Minorias Sexuais e de Gênero , Inquéritos e Questionários , Tenofovir/uso terapêutico
19.
Iran J Biotechnol ; 17(2): e2189, 2019 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-31457061

RESUMO

Background: Enantiopure epoxides are important intermediates in the synthesis of high-value chiral chemicals. Epoxide hydrolases have been exploited in biocatalysis for kinetic resolution of racemic epoxides to produce enantiopure epoxides and vicinal diols. It is necessary to obtain sufficient stable epoxide hydrolases with high enantioselectivity to meet the requirements of industry. Objectives: Enhancement of soluble expression and biochemical characterization of epoxide hydrolases from Bacillus pumilus and B. subtilis. Material and Methods: Homologous genes encoding epoxide hydrolases from B. pumilus and B. subtilis were cloned and expressed in Escherichia coli. The recombinant epoxide hydrolases were characterized biochemically. Results: Low temperature induction of expression and a C-terminal-fused His-tag enhanced soluble expression of the epoxide hydrolases from the two Bacillus species in E. coli. These epoxide hydrolases could hydrolyze various epoxide substrates, with stereoselectivity toward some epoxides such as styrene oxide and glycidyl tosylate. Conclusions: The position of the His-tag and the induction temperature were found to play a vital role in soluble expression of these two epoxide hydrolases in E. coli. In view of their catalytic properties, the epoxide hydrolases from Bacillus have potential for application in kinetic resolution of some epoxides to prepare enantiopure epoxides and vicinal diols.

20.
J Infect Dis ; 220(12): 1892-1903, 2019 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-31433832

RESUMO

BACKGROUND: Natural killer (NK) cells are an important type of effector cell in the innate immune response, and also have a role in regulation of the adaptive immune response. Several studies have indicated that NK cells may influence CD4+ T cells during HIV infection. METHODS: In total, 51 HIV-infected individuals and 15 healthy controls participated in this study. We performed the flow cytometry assays and real-time PCR for the phenotypic analysis and the functional assays of NK cell-mediated deletion of CD4+ T cells, phosphorylation of nuclear factor-κB (NF-κB/p65) and the intervention of metformin. RESULTS: Here we detected high CD54 expression on CD4+ T cells in HIV-infected individuals, and demonstrate that upregulated CD54 is associated with disease progression in individuals infected with HIV. We also show that CD54 expression leads to the deletion of CD4+ T cells by NK cells in vitro, and that this is modulated by NF-κB/p65 signaling. Further, we demonstrate that metformin can suppress CD54 expression on CD4+ T cells by inhibiting NF-κB/p65 phosphorylation. CONCLUSIONS: Our data suggest that further studies to evaluate the potential role of metformin as adjunctive therapy to reconstitute immune function in HIV-infected individuals are warranted.

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