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ABSTRACT The objective of this study was to describe country-specific lockdown measures and tuberculosis indicators collected during the first year of the COVID-19 pandemic. Data on lockdown/social restrictions (compulsory face masks and hand hygiene; international and local travel restrictions; restrictions to family visits, and school closures) were collected from 24 countries spanning five continents. The majority of the countries implemented multiple lockdowns with partial or full reopening. There was an overall decrease in active tuberculosis, drug-resistant tuberculosis, and latent tuberculosis cases. Although national lockdowns were effective in containing COVID-19 cases, several indicators of tuberculosis were affected during the pandemic.
RESUMO O objetivo deste estudo foi descrever as medidas de confinamento específicas de cada país e os indicadores de tuberculose coletados durante o primeiro ano da pandemia de COVID-19. Dados referentes a confinamento/restrições sociais (uso obrigatório de máscaras faciais e higiene obrigatória das mãos; restrições a viagens internacionais e locais; restrições a visitas familiares e fechamento das escolas) foram coletados de 24 países em cinco continentes. A maioria dos países implantou múltiplos confinamentos, com reabertura parcial ou total. Houve uma redução geral dos casos de tuberculose ativa, tuberculose resistente e tuberculose latente. Embora os confinamentos nacionais tenham sido eficazes na contenção dos casos de COVID-19, vários indicadores de tuberculose foram afetados durante a pandemia.
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Antibody-drug conjugates(ADCs)are commonly heterogeneous and require extensive assessment of exposure-efficacy and exposure-safety relationships in preclinical and clinical studies.In this study,we report the generation of a monoclonal antibody against monomethyl auristatin E(MMAE)and the development,validation,and application of sensitive and high-throughput enzyme-linked immunosor-bent assays(ELISA)to measure the concentrations of MMAE-conjugated ADCs and total antibodies(tAb,antibodies in ADC plus unconjugated antibodies)in cynomolgus monkey sera.These assays were suc-cessfully applied to in vitro plasma stability and pharmacokinetic(PK)studies of SMADC001,an MMAE-conjugated ADC against trophoblast cell surface antigen 2(TROP-2).The plasma stability of SMADC001 was better than that of similar ADCs coupled with PEG4-Val-Cit,Lys(m-dPEG24)-Cit,and Val-Cit linkers.The developed ELISA methods for the calibration standards of ADC and tAb revealed a correlation be-tween serum concentrations and the OD450 values,with R2 at 1.000,and the dynamic range was 0.3-35.0 ng/mL and 0.2-22.0 ng/mL,respectively;the intra-and inter-assay accuracy bias％ranged from-12.2％to-5.2％,precision ranged from-12.4％to-1.4％,and the relative standard deviation(RSD)was less than 6.6％and 8.7％,respectively.The total error was less than 20.4％.The development and validation steps of these two assays met the acceptance criteria for all addressed validation parameters,which suggested that these can be applied to quantify MMAE-conjugated ADCs,as well as in PK studies.Furthermore,these assays can be easily adopted for development of other similar immunoassays.
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Objective:To investigate the intervention of <italic>Hedyotis diffusa</italic> （HDW） on colitis associated cancer （CAC） model mice and explore its mechanism. Method:The CAC mouse model was established by synergistic action of azoxymethane （AOM） and dextran sulfate sodium （DSS）. The intervention of HDW on CAC mice was evaluated by disease activity index （DAI）， colonic tissue morphology， pathological injury score and tumorigenesis rate. Ultra-high performance liquid chromatography-quadrupole time-of-flight mass spectrometry （UPLC-Q-TOF-MS） and multivariate statistical analysis were used to analyze the metabonomics of mice serum and to explore the mechanism of HDW intervention on CAC. Result:HDW could significantly improve the general condition of CAC mice， decrease DAI， colon gross morphological score， histopathological score and tumorigenesis rate. Compared with the normal group， 38 kinds of differential metabolites were screened in the model group， including 11 potential biomarkers， involving 11 main metabolic pathways. HDW could significantly regulate 9 kinds of differential metabolites ［niacinamide， uridine， 4-pyridoxic acid， LysoPC （18∶0）， LysoPE （0∶0/20∶0）， myo-inositol， purine， sphinganine 1-phosphate and tetradecanedioic acid］ in the model group， including 2 kinds of potential biomarkers （myo-inositol and niacinamide）， and HDW could regulate nicotinate and nicotinamide metabolism and inositol phosphate metabolism. Conclusion:HDW has a therapeutic effect on CAC， which may be achieved by regulation of energy metabolism and glucose metabolism.
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Osteoarthritis(OA) is a common clinical disease. The incidence of OA increases significantly with age, and the quality of life of patients is seriously affected. In the pathogenesis of OA, cartilage degeneration is the main cause. There are many long non-coding RNA (lncRNA) specifically expressed in osteoarthritis, which is closely related to the occurrence and development of osteoarthritis. Based on the latest research from 2014 to 2019, this paper summarizes the differential expression of lncRNA in osteoarthritis, the mechanism of lncRNA regulating chondrocyte function, and the mechanism of lncRNA regulating cartilage matrix metabolism. The fact that the expression of lncRNA is altered at different stages of OA development indicates that lncRNA can be developed forlife. The biomarkers and therapeutic targets can provide reference for the prevention, treatment and research of osteoarthritis.
Subject(s)
Humans , Chondrocytes , Osteoarthritis/genetics , Quality of Life , RNA, Long Noncoding/genetics , ResearchABSTRACT
This research investigated the effect of parthenolide on the proliferation and migration of human breast cancer cells and explored the molecular mechanism of that effect. Surface plasmon resonance and fluorescence resonance energy transfer melting were used to detect the binding and stabilizing ability of PTL and G-quadruplex. MTT assays were used to determine the effect of PTL on the proliferation of MCF-7 breast cancer cells. A wound healing assay was performed to detect the migration of MCF-7. The results indicate that PTL shows good binding and stabilizing activities with c-myc G-quadruplex with a KD = 13.1 μmol·L-1. PTL inhibited the proliferation of MCF-7 cells with an IC50 of 21.3 μmol·L-1 (24 h), 14.5 μmol·L-1 (48 h) and 9.1 μmol·L-1 (72 h). PTL inhibited MCF-7 breast cancer cell proliferation and migration and down-regulated the transcription and expression level of c-myc by targeting G-quadruplex.
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Snow lotus is a medicinal plant with a wide range of pharmacological activities. It has been used to treat rheumatoid arthritis, cough with cold, stomach ache, dysmenorrhea, and altitude sickness in traditional medicine. This review summarizes the bioactive components in six species of snow lotus including flavonoids, lignans, phenolic compounds, phenylpropanoids, and sesquiterpenes present in Saussurea involucrate (SI), Saussurea obvallata (SO), Saussurea laniceps (SL), Saussurea medusa (SM), Saussurea stella (SS) and Saussurea tridactyla (ST). We review the pharmacological and related molecular mechanisms by which these components exert antineoplastic, anti-inflammatory, and antioxidant effects and promote lipid catabolism, and provide a reference for the future study of the traditional Chinese medicinal chemistry and pharmacological activities of snow lotus.
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OBJECTIVE@#To explore distal Chevron osteotomy of the first metatarsal and soft-tissue release for the treatment of mild and moderate hallux valgus.@*METHODS@#From June 2015 to June 2017, 32 patients(40 feet) with mild and moderate hallux valgus were treated with distal Chevron osteotomy with soft tissue release. including 3 males(3 feet) and 29 females (37 feet), aged from 22 to 80 years old with an average of 57.57 years old. The courses of disease ranged from 2 to 32 years with an average of 14 years. Among them, 9 feet were mild, 31 feet were moderate. Patients were combined with bunion, pain around the first metatarsal joint, and pain increased during weight-bearing walking before opertaion. AP and lateral X-rays on weight-bearing were performed, hallux valgus angle(HVA) and intermetatarsal angle(IMA) between the first and the second metatarsal were examined before and after operation. AOFAS score was applied to evaluate clinical effects.@*RESULTS@#All patients were followed up from 12 to 24 months with an average of 15.2 months.Fracture wounds were healed well without infection and metatarsal head necrosis occurred. Preoperative HVA (32.08±5.59)° and IMA (11.63±2.24)° decreased to (10.31±4.36)° and (5.02°±2.34)°after operation at 12 months, and had statistical difference before and after operation (<0.05). AOFAS score increased from 56.75±6.42 before operation to 88.80±3.99 after operation at 12 months(<0.05).@*CONCLUSIONS@#Distal Chevron osteotomy of the first metatarsal and soft-tissue release for the treatment of mild and moderate hallux valgus could obtain good effects and provide more options for hallux valgus treatment.
Subject(s)
Adult , Aged , Aged, 80 and over , Female , Humans , Male , Middle Aged , Young Adult , Bunion , Hallux Valgus , General Surgery , Metatarsal Bones , Osteotomy , Radiography , Treatment OutcomeABSTRACT
OBJECTIVE@#To investigate the relationship of miR-140 expression level with the therapeutic effect of decitabine, and to explore whether the molecular mechanism is dependent on the regulation of TLR4 expression.@*METHODS@#Forty-seven patients with acute myeloid leukaemia (AML) were enrolled in our study and divided into decitabine combination treatment group (22 cases) and traditional treatment group (25 cases). The clinical efficacy was compared between these two groups. Real-time PCR was used to determine the plasma level of miR-140 in AML patients. Decitabine, miR-140 mimic and miR140 inhibitor were used to treat AML HL-60 cells in vitro, the real-time PCR and Western blot were used to detect the expressions of miR-140, TLR4 and NF-κB at both mRNA and protein levels.@*RESULTS@#Compared with traditional treatment group, decitabine combination treatment group showed more significant clinical efficacy. Plasma miR-140 level in both 2 treatment groups both decreased, but the plasma miR-140 level was higher in decitabine combination treatment group as compared with traditional treatment group. Experiment in vitro showed that 0.3 μmol/L decitabine significantly inhibited the HL-60 cell proliferation accompanied by up-regulation of miR-140 expression and down-regulation of expression of TLR4 and NF-κB. These effects induced by decitabine were partly reversed by pretreating the cells with 200 nmol/L miR-140 inhibitor.@*CONCLUSION@#Decitabine-induced up-regulation of miR-140 expression may be related with its chemotherapeutic effects, and miR-140/TLR4/NF-κB pathway may partly mediate the pharmacologic action of decitabine.
Subject(s)
Humans , Decitabine , Therapeutic Uses , Down-Regulation , HL-60 Cells , Leukemia, Myeloid, Acute , Drug Therapy , MicroRNAs , NF-kappa BABSTRACT
BACKGROUND/OBJECTIVES: Docosahexaenoic acid (DHA), an n-3 long chain polyunsaturated fatty acid (LCPUFA), is acquired by dietary intake or the in vivo conversion of α-linolenic acid. Many enzymes participating in LCPUFA synthesis are regulated by peroxisome proliferator-activated receptor alpha (PPARα). Therefore, it was hypothesized that the tissue accretion of endogenously synthesized DHA could be modified by PPARα. MATERIALS/METHODS: The tissue DHA concentrations and mRNA levels of genes participating in DHA biosynthesis were compared among PPARα homozygous (KO), heterozygous (HZ), and wild type (WT) mice (Exp I), and between WT mice treated with clofibrate (PPARα agonist) or those not treated (Exp II). In ExpII, the expression levels of the proteins associated with DHA function in the brain cortex and retina were also measured. An n3-PUFA depleted/replenished regimen was applied to mitigate the confounding effects of maternal DHA. RESULTS: PPARα ablation reduced the hepatic Acox, Fads1, and Fads2 mRNA levels, as well as the DHA concentration in the liver, but not in the brain cortex. In contrast, PPARα activation increased hepatic Acox, Fads1, Fads2 and Elovl5 mRNA levels, but reduced the DHA concentrations in the liver, retina, and phospholipid of brain cortex, and decreased mRNA and protein levels of the brain-derived neurotrophic factor in brain cortex. CONCLUSIONS: LCPUFA enzyme expression was altered by PPARα. Either PPARα deficiency or activation-decreased tissue DHA concentration is a stimulus for further studies to determine the functional significance.
Subject(s)
Animals , Mice , Brain , Brain-Derived Neurotrophic Factor , Clofibrate , Docosahexaenoic Acids , Fatty Acid Desaturases , Liver , Peroxisomes , PPAR alpha , Retina , RNA, MessengerABSTRACT
OBJECTIVE@#To evaluate the efficacy and safety of Tongxiening Granules (, TXNG) in the treatment of irritable bowel syndrome with predominant diarrhea (IBS-D).@*METHODS@#A randomized, double-blind, double-dummy, and positive parallel controlled clinical trial was conducted from October 2014 to March 2016. Totally 342 patients from 13 clinical centers were enrolled and randomly assigned (at the ratio of 1:1) to a treatment group (171 cases) and a control group (171 cases) by a random coding table. The patients in the treatment group were administered orally with TXNG (5 g per time) combined with pinaverium bromide Tablet simulator (50 mg per time), 3 times per day. The patients in the control group were given TXNG simulator (5 g per time) combined with pinaverium bromide Tablets (50 mg per time), 3 times per day. The treatment course lasted for 6 weeks. The improvement of Irritable Bowel Syndrome Symptom Severity Score (IBS-SSS) was used to evaluate the primary outcome. Secondary outcomes included adequate relief (AR) rate, Irritable Bowel Syndrome-Quality of Life Questionnaire (IBS-QOL), Hamilton Anxiety Scale (HAMA), Hamilton Depression Scale (HAMD), and the recurrence rate at follow-ups. Safety indices including the adverse events (AEs) and related laboratory tests were evaluated.@*RESULTS@#Primary outcome: IBS-SSS at baseline, weeks 2, 4, 6 showed no statistical significance in both full analysis set (FAS) and per protocol set (PPS, P>0.05). After 6 weeks of treatment, the total effective rate of IBS-SSS scores in the treatment group (147/171,86.0%) was higher than the control group (143/171, 83.6%) by FAS (P>0.05). In regard to secondary outcomes, after 6-week treatment, there was no significant difference in AR rate, total score of IBS-QOL, improvement of HAMD and HAMA total scores between the two groups (P>0.05). The recurrence rate at 8-week follow-up was 12.35% (10/18) in treatment group and 15.79% (12/76) in control group, respectively (P>0.05). A total of 21 AEs occurred in 15 cases, of which 11 occurred in 8 cases in the treatment group and 10 AEs in 7 cases in the control group. The incidence of AEs had no statistical significance between the two goups (P>0.05).@*CONCLUSION@#Tongxiening Granules could relieve the symptoms of patients with IBS-D and the treatment effect was comparable to pinaverium bromide. (No. ChiCTR-IPR-15006415).
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Chorismate synthase(CS, EC:4.2.3.5) catalyses 5-enolpyruvy-shikimate-3-phosphate to form chorismate, which is the essential enzyme for chorismate biosynthesis in organisms. The amino acid sequences of CS from 79 species of higher plants were reported in GenBank at present. 125 amino acid sequences of CS from Baphicacanthus cusia and other 78 species of plants were predicted and analyzed by using various bioinformatics software, including the composition of amino acid sequences, signal peptide, leader peptide, hydrophobic/hydrophilic, transmembrane structure, coiled-coil domain, protein secondary structure, tertiary structure and functional domains. The phylogenetic tree of CS protein family was constructed and divided into eight groups by phylogenetic analysis. The homology comparison indicated that B. cusia shared a high homology with several plants such as Sesamum indicum, Nicotiana tabacum, Solanum tuberosum and so on. The open reading frame(ORF) of all samples is about 1 300 bp, the molecular weight is about 50 kDa, the isoelectric point(pI) is 5.0-8.0 which illustrated that CS protein is slightly basic. The ORF of CS we cloned in B. cusia is 1 326 bp, the amino acid residues are 442, the molecular weight is 47 kDa and pI is 8.11. The CS in B.cusia showed obvious hydrophobicity area and hydrophilicity area, no signal peptide, and may exists transmembrane structure areas. The main secondary structures of CS protein are random coil and Alpha helix, also contain three main structural domains which are an active structural domain, a PLN02754 conserved domain and a FMN binding site. The acquired information in this study would provide certain scientific basis for further study on structure-activity relationship and structure modification of CS in plants in the future.
Subject(s)
Acanthaceae , Amino Acid Sequence , Computational Biology , Phosphorus-Oxygen Lyases , Chemistry , Phylogeny , Plant Proteins , Chemistry , Protein Structure, SecondaryABSTRACT
<p><b>OBJECTIVE</b>To explore the growth inhibitory effect of quercetin on imatinib-resistant chronic myeloid leukemia cell lines and to clarify its involved mechanisms.</p><p><b>METHODS</b>The cell viability was detected by trypan blue Staining, percentage of apoptotic cells and cell cycle distribution were detected by flow cytometry, the protein expression was detected by Western blot.</p><p><b>RESULTS</b>Both inhibitory effect of proliferation and apoptosis-inducing effect were similar between the imatinib-resistant and -sensitive cell lines treated with 25 µmol/L quercetin for 24 hours and with arrest of cell cycle at G/M phase. Quercetin could not change the expression of BCR-ABL. The expression of γ-H2AX was markedly enhanced and the phosphorylation of JNK up-regulated by quercetin in both imatinib-resistant and imatinib-sensitive cell lines.</p><p><b>CONCLUSION</b>The growth of imatinib-resistant cells can be inhibited by quercetin, and the apoptosis of cells can be induced by quercetin, which may be related to cell cycle arrest in G/M. The DNA damage and up-regulation of p-JNK may be involved in these processes.</p>
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Objective To evaluate the feasibilities and advantages of different concentrations of sodium alginate (SA) solutions as a submucosal injection solution for endoscopic submucosal dissection (ESD). Methods In vitro study, different concentrations of sodium alginate solutions and normal saline were injected into submucosal of resected porcine esophagus and stomach respectively, then observe and measure the heights of each injection induced mucosal elevations, and their changes over time. In vivo study, the mimic ESD were conducted in healthy pigs to evaluate the mucosal elevation effect and other assistant effects of sodium alginate as a submucosal injection solution. Results The elevation heights of the experiment groups injected with SA solutions were much higher than the control group injected with normal saline. Specially, the elevation created by 1 % SA in porcine esophagus was significantly higher than that of normal saline (P < 0.01) and the elevation created by 3 % SA was significantly higher than that of normal saline in porcine stomach (P < 0.001). In the mimic ESD experiment, mucosal elevation with clear margin occurred immediately after injection with SA solution. And the durable submucosal fluid cushion created by SA protected deeper tissues while facilitating ESD procedure. Conclusion The elevation heights created by SA solutions were greater and more durable than that created by normal saline, which were crucial for ESD. The viscosity property enabled SA to form a stable protective cushion and prevent bleeding by squeezing tissue around the wound, which may decrease perforation and bleeding rate during ESD procedure. Therefore, sodium alginate can be an ideal clinical submucosal injection solution.
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Iatrogenic gastrointestinal perforation is one of the severe adverse events of endoscopic therapeutic procedure. For acute iatrogenic perforation,management by endoscopic techniques is a simple and rapid modality to close the perforation with minimal invasiveness and avoiding the traditional surgical trauma. Endoclips,suture with special instruments,covered stents,degradable sheets combined with tissue adhesive,and combined endoscopic techniques such as snares combined with endoclips,are the major endoscopic therapeutic modalities for closure of iatrogenic gastrointestinal perforation. In this article,the current status and progress of endoscopic management for acute iatrogenic gastrointestinal perforation were reviewed.
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This study was aimed to explore the effect of bortezomib and low concentration cytarabine (Ara-C) on proliferation and apoptosis in U937 cell line and its mechanism. The proliferation and apoptosis of U937 cells treated with bortezomib (10 nmol/L) and(or) Ara-C (50 nmol/L) were observed by cell count, cell morphology, flow cytometry and Western blot. The results showed that bortezomib and Ara-C alone inhibited U937 cell proliferation. The inhibitory effect was enhanced by combination of these two drugs, the inhibitory rates of U937 cell proliferation were (55.00 ± 2.81)% and (70.02 ± 3.33)% after treatment for 24 h and 48 h, respectively. Bortezomib and Ara-C synergistically induced apoptosis and decreased mitochondrial membrane potential in U937 cells. The percentage of Rhodamin123 positive cells was (38.70 ± 1.54)%. Bortezomib and Ara-C also synergistically induced activation of caspase-9, caspase-8 and caspase-3. It is concluded that the bortezomib and low concentration Ara-C synergistically induced apoptosis in U937 cells, mainly through mitochondrial pathway, and possibly through death receptor pathway.
Subject(s)
Humans , Apoptosis , Boronic Acids , Pharmacology , Bortezomib , Cell Cycle , Cytarabine , Pharmacology , Pyrazines , Pharmacology , U937 CellsABSTRACT
This study was aimed to further explore the apoptosis-inducing effect of bortezomib combined with cytarabine (Ara-C) on U937 cell line. Proliferation and apoptosis in U937 cells treated with bortezomib and/or Ara-C were assessed by cell count. Cell cycle distribution and reactive oxygen species (ROS) production level were measured by using flow cytometry. Cell signaling pathway related to apoptosis was analyzed by Western blot. The results showed that 10 nmol/L bortezomib combined with 50 nmol/L Ara-C significantly inhibited U937 cell proliferation. These two drug combination synergistically induced apoptosis in U937 cells, significantly increased cellular ROS level, and up-regulated the expression of phosphorylated form of JNK and P38 and down-regulated phosphorylation of ERK. It is concluded that the apoptosis of U937 cells synergistically induced by bortezomib combined with low concentration Ara-C is possibly associated with up-regulation of phosphorylated form of JNK, P38 and down-regulation of phosphorylation of ERK induced by increase of ROS, resulting in decrease of mitochondrial potential.
Subject(s)
Humans , Apoptosis , Boronic Acids , Pharmacology , Bortezomib , Cytarabine , Pharmacology , Drug Synergism , Gene Expression Regulation, Neoplastic , MAP Kinase Signaling System , Phosphorylation , Pyrazines , Pharmacology , Reactive Oxygen Species , Metabolism , U937 CellsABSTRACT
This study was purposed to investigate the expression of ifi56 gene in the ATRA-induced acute promyelocytic leukemia (APL) NB4 cell differentiation and to construct the eukaryotic expression plasmid of ifi56 gene. RT-PCR was used to detect the expression of ifi56 in NB4 cells treated with ATRA for different time. Human ifi56 cDNA was amplified by RT-PCR and cloned into pEGFP-C1 vector, then was transfected into 293T cells. The expression of the recombinant protein in 293T cells was detected by Western blot. The localization of IFI56 protein was observed by fluorescence microscopy. The results showed that the ifi56 mRNA was almost undetectable in untreated NB4 cells, but it significantly increased after ATRA treatment for 72 hours. The cDNA fragment of ifi56 was inserted into the expressing plasmid pEGFP-C1 successfully. The expression of EGFP-IFI56 fusion protein with a molecular weight about 83 kD was detected by Western blot. The EGFP-IFI56 protein was localized in cytoplasm mainly. It is concluded that the expression of ifi56 is enhanced significantly when the differentiation of APL cells was induced by ATRA. Gene ifi56 is successfully cloned into eukaryotic expression vector and the fusion protein is expressed in the cytoplasm mainly.
Subject(s)
Humans , Carrier Proteins , Genetics , Cell Differentiation , Genetics , Cell Line, Tumor , Gene Expression , Genetic Vectors , Leukemia, Promyelocytic, Acute , Genetics , Recombinant Fusion Proteins , Genetics , Tretinoin , PharmacologyABSTRACT
To investigate the molecular mechanisms of all-trans retinoic acid (ATRA)-induced rig-g gene expression and to better understand the signal transduction of ATRA during acute promyelocytic leukemia (APL) cell differentiation, the luciferase reporter assay, co-immunoprecipitation and chromatin immunoprecipitation were used to clarify the basic transcriptional factors, which directly initiated the expression of rig-g gene. The results showed that the expression of STAT2, IRF-9 and IRF-1 could be upregulated by ATRA with different kinetics in NB4 cells. IRF-9 was able to interact with STAT2 to form a complex, which could bind the rig-g gene promoter and trigger the rig-g expression. IRF-1 alone could also activate the reporter gene containing rig-g gene promoter, but C/EBPalpha could strongly inhibit this transcription activity of IRF-1. It is concluded that during ATRA-induced APL cell differentiation, IRF-1 is first upregulated by ATRA, and then IRF-1 increases the protein levels of IRF-9 and STAT2 with the downregulation of C/EBPalpha. The complex of IRF-9 and STAT2 is the primary transcriptional factor for rig-g gene induction. This study will be helpful for better understanding the signal transduction networks of ATRA during the course of APL cell differentiation.
Subject(s)
Humans , CCAAT-Enhancer-Binding Protein-alpha , Metabolism , Gene Expression Regulation, Leukemic , Genes, Regulator , Interferon Regulatory Factor-1 , Metabolism , Interferon-Stimulated Gene Factor 3, gamma Subunit , Metabolism , Intracellular Signaling Peptides and Proteins , Genetics , Leukemia, Promyelocytic, Acute , Genetics , STAT2 Transcription Factor , Metabolism , Signal Transduction , Tretinoin , Pharmacology , Tumor Cells, CulturedABSTRACT
<p><b>OBJECTIVE</b>To study the regulatory role of interferon-stimulated response elements (ISREs) located on the retinoic acid-induced gene G (RIG-G) promoter in RIG-G expression.</p><p><b>METHODS</b>By using point mutation technique, the authors constructed the wide type and site mutant reporter gene plasmids according to the ISRE sequence on RIG-G promoter, and detected the functional activities by luciferase reporter assay.</p><p><b>RESULTS</b>Mutation in ISRE II alone had no obvious effect on the expression of the reporter gene, whereas mutation in ISRE I dramatically inhibited the transactivity of RIG-G promoter. Mutation in both ISRE I and ISRE II resulted in complete loss of its response to the transcription factors for the reporter gene.</p><p><b>CONCLUSION</b>Both ISRE I and ISRE II on the RIG-G promoter are the binding sites for the complex of transcription factors. They are required for RIG-G expression, and ISRE I has a preferential role over ISRE II.</p>
Subject(s)
Humans , Cell Line, Tumor , Interferon Regulatory Factor-1 , Genetics , Metabolism , Interferons , Genetics , Metabolism , Intracellular Signaling Peptides and Proteins , Genetics , Mutation , Promoter Regions, Genetic , Genetics , Response Elements , Genetics , STAT2 Transcription Factor , Genetics , MetabolismABSTRACT
<p><b>OBJECTIVE</b>To investigate the molecular mechanisms by which IFN-alpha regulated retinoic acid-induced gene G (RIG-G) expression.</p><p><b>METHODS</b>The expression of STAT1, p-STAT1 and RIG-G in IFN-alpha-treated NB4 cells was detected by Western blot. The roles of STAT1, STAT2 and IRF-9 in IFN-alpha-induced RIG-G expression were analyzed in STAT1-null U3A cells by cell transfection, reporter gene assay, co-immunoprecipitation and chromatin immunoprecipitaion.</p><p><b>RESULTS</b>In U3A cells, only when STAT2 and IRF-9 were co-transfected, the luciferase activities of RIG-G promoter-containing reporter gene could be highly increased about 8-fold compared with that in the control group. Moreover, in the absence of IFN-alpha, similar effects were observed in either IRF-9 co-transfected with wild type or mutant form of STAT2, whereas IFN-alpha could increase the transactivation activity of wild type STAT2 and IRF-9 by 6-fold compared with that without IFN-alpha, but had no effect on mutant STAT2. In addition, STAT2 could interact with IRF-9 and bind to the RIG-G promoter.</p><p><b>CONCLUSION</b>STAT2 may interact with IRF-9 in a STAT1-independent manner. The complex STAT2/IRF-9 is the key factor mediating the expression of RIG-G gene regulated by IFN-alpha. This is a novel signal transduction cascade for IFN which is different from the classical JAK-STAT pathway.</p>