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MBio Apr 2016As key components of innate immune defense, macrophages are essential in controlling bacterial pathogens, including group A Streptococcus(GAS). Despite this, only a...
UNLABELLED
As key components of innate immune defense, macrophages are essential in controlling bacterial pathogens, including group A Streptococcus(GAS). Despite this, only a limited number of studies have analyzed the recovery of GAS from within human neutrophils and macrophages. Here, we determined the intracellular fate of GAS in human macrophages by using several quantitative approaches. In both U937 and primary human macrophages, the appearance over time of long GAS chains revealed that despite GAS-mediated cytotoxicity, replication occurred in viable, propidium iodide-negative macrophages. Whereas the major virulence factor M1 did not contribute to bacterial growth, a GAS mutant strain deficient in streptolysin O (SLO) was impaired for intracellular replication. SLO promoted bacterial escape from the GAS-containing vacuole (GCV) into the macrophage cytosol. Up to half of the cytosolic GAS colocalized with ubiquitin and p62, suggesting that the bacteria were targeted by the autophagy machinery. Despite this, live imaging of U937 macrophages revealed proficient replication of GAS after GCV rupture, indicating that escape from the GCV is important for growth of GAS in macrophages. Our results reveal that GAS can replicate within viable human macrophages, with SLO promoting GCV escape and cytosolic growth, despite the recruitment of autophagy receptors to bacteria.
IMPORTANCE
Classically regarded as an extracellular pathogen, GAS can persist within human epithelial cells, as well as neutrophils and macrophages. Some studies suggest that GAS can modulate its intracellular vacuole to promote survival and perhaps replicate in macrophages. However, an in-depth single-cell analysis of the dynamics of survival and replication is lacking. We used macrophage-like cell lines and primary macrophages to measure the intracellular growth of GAS at both the population and single-cell levels. While CFU counts revealed no increase in overall bacterial growth, quantitative fluorescence microscopy, flow cytometry, and time-lapse imaging revealed bacterial replication in a proportion of infected macrophages. This study emphasizes the importance of single-cell analysis especially when studying the intracellular fate of a pathogen that is cytotoxic and displays heterogeneity in terms of intracellular killing and growth. To our knowledge, this study provides the first direct visualization of GAS replication inside human cells.
Topics: Bacterial Proteins; Cytosol; Humans; Macrophages; Microbial Viability; Streptococcal Infections; Streptococcus pyogenes; Streptolysins; U937 Cells; Virulence Factors
PubMed: 27073088
DOI: 10.1128/mBio.00020-16 -
Blood May 2011CCAAT/enhancer binding protein-α (CEBPA) mutations in acute myeloid leukemia (AML) patients with a normal karyotype (NK) confer favorable prognosis, whereas NK-AML...
CCAAT/enhancer binding protein-α (CEBPA) mutations in acute myeloid leukemia (AML) patients with a normal karyotype (NK) confer favorable prognosis, whereas NK-AML patients per se are of intermediate risk. This suggests that blocked CEBPA function characterizes NK-AML with favorable outcome. We determined the prognostic significance of CEBPA DNA binding function by enzyme-linked immunosorbent assay in 105 NK-AML patients. Suppressed CEBPA DNA binding was defined by 21 good-risk AML patients with inv(16) or t(8;21) (both abnormalities targeting CEBPA) and 8 NK-AML patients with dominant-negative CEBPA mutations. NK-AML patients with suppressed CEBPA function showed a better overall survival (P = .0231) and disease-free survival (P = .0069) than patients with conserved CEBPA function. Suppressed CEBPA DNA binding was an independent marker for better overall survival and disease-free survival in a multivariable analysis that included FLT3-ITD, NPM1 and CEBPA mutation status, white blood cell count, age and lactate dehydrogenase. These data indicate that suppressed CEBPA function is associated with favorable prognosis in NK-AML patients.
Topics: Adolescent; Adult; Aged; Base Sequence; CCAAT-Enhancer-Binding Proteins; Core Binding Factor Alpha 2 Subunit; DNA, Neoplasm; Female; Humans; Kaplan-Meier Estimate; Karyotyping; Leukemia, Myeloid, Acute; Male; Middle Aged; Mutation; Nucleophosmin; Oncogene Proteins, Fusion; Prognosis; RNA, Messenger; RNA, Neoplasm; RUNX1 Translocation Partner 1 Protein; U937 Cells; Young Adult
PubMed: 21389317
DOI: 10.1182/blood-2010-11-320747 -
BMC Cancer Nov 2021Despite of the frequently reported Dnmt3a abormality in classical myeloproliferative neoplasms (cMPNs) patients, few research explores how the Dnmt3a is regulated by...
BACKGROUND
Despite of the frequently reported Dnmt3a abormality in classical myeloproliferative neoplasms (cMPNs) patients, few research explores how the Dnmt3a is regulated by Jak2 mutation. In this study, we have investigated how the Dnmt3a is regulated by Jak2 mutation and its effects on downstream signaling pathways in cMPNs.
METHODS
Specimens of Jak2 positive cMPN patients and normal controls were collected. Murine BaF3 cell line was used to construct cell models. Dual-Glo luciferase assays and chromatin immunoprecipitation (ChIP)-qPCR were performed to detect the impact of Stat5a on transcription activity of Dnmt3a. Soft agar colony formation assay and cell counting assay were performed to detect cell proliferation. BrdU staining and flow cytometry were used to investigate cell cycle distribution. Western blotting and quantitative reverse-transcription PCR (qPCR) were performed to detect the expression levels of genes.
RESULTS
Firstly, the results of western blotting and qPCR revealed that compared with the control samples, Dnmt3a is downregulated in Jak2 positive samples. Then we explored the mechanism behind it and found that Dnmt3a is a downstream target of Stat5a, the transcription and translation of Dnmt3a is suppressed by the binding of aberrantly activated Stat5a with Dnmt3a promoter in Jak2 positive samples. We further revealed the region approximately 800 bp upstream of the first exon of the Dnmt3a promoter, which includes a gamma-activated sequence (GAS) motif of Stat5a, is the specific site that Stat5a binds to. Soft agar colony formation assay, cell counting assay, and BrdU staining and flow cytometry assay found that Dnmt3a in Jak2-BaF3 cells significantly affected the cell proliferation capacity and cell cycle distribution by suppressing Cdkn1a via miR-17-5p/Cdkn1a axis and mediated G0/G1 arrest.
CONCLUSIONS
Transcription and translation of Dnmt3a is downregulated by the binding of Stat5a with Dnmt3a promoter in Jak2 cells. The GAS motif at promoter of Dnmt3a is the exact site where the Stat5a binds to. Dnmt3a conducted G0/G1 arrest through regulating miR-17-5p/Cdkn1a axis. The axis of Stat5a/Dnmt3a/miR-17-5p/Cdkn1a potentially provides a treatment target for cMPNs.
Topics: Aminopyridines; Animals; Binding Sites; Blotting, Western; Case-Control Studies; Cell Count; Cell Line; Cell Line, Tumor; Cell Proliferation; Cyclin-Dependent Kinase Inhibitor p21; DNA Methyltransferase 3A; Down-Regulation; Exons; G1 Phase Cell Cycle Checkpoints; Humans; Imidazoles; Janus Kinase 2; K562 Cells; Mice; MicroRNAs; Monocytes; Mutation; Myeloproliferative Disorders; Promoter Regions, Genetic; Pyrazoles; Pyridazines; STAT5 Transcription Factor; Signal Transduction; Transcription, Genetic; Tumor Stem Cell Assay; Tumor Suppressor Proteins; U937 Cells
PubMed: 34773997
DOI: 10.1186/s12885-021-08915-0 -
British Journal of Cancer Aug 2017Lurbinectedin is a novel anticancer agent currently undergoing late-stage (Phase II /III) clinical evaluation in platinum-resistant ovarian, BRCA1/2-mutated breast and...
BACKGROUND
Lurbinectedin is a novel anticancer agent currently undergoing late-stage (Phase II /III) clinical evaluation in platinum-resistant ovarian, BRCA1/2-mutated breast and small-cell lung cancer. Lurbinectedin is structurally related to trabectedin and it inhibits active transcription and the DNA repair machinery in tumour cells.
METHODS
In this study we investigated whether lurbinectedin has the ability to modulate the inflammatory microenvironment and the viability of myeloid cells in tumour-bearing mice.
RESULTS
Administration of lurbinectedin significantly and selectively decreased the number of circulating monocytes and, in tumour tissues, that of macrophages and vessels. Similar findings were observed when a lurbinectedin-resistant tumour variant was used, indicating a direct effect of lurbinectedin on the tumour microenviroment. In vitro, lurbinectedin induced caspase-8-dependent apoptosis of human purified monocytes, whereas at low doses it significantly inhibited the production of inflammatory/growth factors (CCL2, CXCL8 and VEGF) and dramatically impaired monocyte adhesion and migration ability. These findings were supported by the strong inhibition of genes of the Rho-GTPase family in lurbinectedin-treated monocytes.
CONCLUSIONS
The results illustrate that lurbinectedin affects at multiple levels the inflammatory microenvironment by acting on the viability and functional activity of mononuclear phagocytes. These peculiar effects, combined with its intrinsic activity against cancer cells, make lurbinectedin a compound of particular interest in oncology.
Topics: Animals; Antineoplastic Agents, Alkylating; Apoptosis; Carbolines; Caspase 8; Cell Adhesion; Cell Movement; Chemokine CCL2; Dioxoles; Down-Regulation; Female; Fibrosarcoma; Gene Expression; Gene Expression Profiling; HL-60 Cells; Heterocyclic Compounds, 4 or More Rings; Humans; Interleukin-8; Leukocyte Count; Macrophages; Mice; Mice, Inbred C57BL; Monocytes; Neovascularization, Pathologic; Ovarian Neoplasms; Tetrahydroisoquinolines; Trabectedin; Tumor Microenvironment; U937 Cells; Vascular Endothelial Growth Factor A; Xenograft Model Antitumor Assays; rho GTP-Binding Proteins
PubMed: 28683469
DOI: 10.1038/bjc.2017.205 -
Molecular Medicine Reports Sep 2015Neutrophil elastase (NE) is an early myeloid-specific serine protease, which is predominantly produced by promyelocytes. A previous study demonstrated that NE has an...
Neutrophil elastase (NE) is an early myeloid-specific serine protease, which is predominantly produced by promyelocytes. A previous study demonstrated that NE has an important role in the development of acute promyelocytic leukemia (APL). The process of APL was shown to be accelerated in animals that expressed abundant NE, whereas NE‑deficient mice were protected from APL development; thus suggesting an important role for NE in the development of APL. The present study aimed to investigate the effects and possible mechanisms of NE. Up- and downregulation of NE in various leukemia cell lines was conducted in order to explore its significance in the occurrence and procession of leukemia, with the aim of identifying novel targeted therapeutic drugs for the treatment of leukemia. NE was overexpressed in cells following infection with an adenovirus, and Cell Counting kit‑8 and flow cytometry results demonstrated that cell proliferation was promoted, and cell apoptosis was inhibited, as compared with the untreated cells. NE was downregulated in the cells by both RNA interference and treatment with GW311616A, a specific inhibitor of NE, following which cell growth was shown to be inhibited and apoptosis was induced. These results suggested that NE may promote the development of APL, therefore, NE may be a therapeutic target and its inhibitor GW311616A may be a potential therapeutic drug for leukemia. Furthermore, the apoptosis‑associated protein B‑cell lymphoma 2 (Bcl‑2)‑associated X protein was significantly increased, whereas Bcl‑2 was markedly decreased in the cells with downregulated NE. Further experiments revealed that the probable apoptosis‑associated signaling pathway was the phosphoinositide 3‑kinase/AKT pathway. The present study is the first, to the best of our knowledge, to demonstrate that GW311616A, a specific NE inhibitor, may act as a potential targeted drug for leukemia, which may have a profound impact on the future of leukemia-targeted therapy.
Topics: Apoptosis; Cell Line, Tumor; Cell Proliferation; Down-Regulation; Humans; K562 Cells; Leukemia, Promyelocytic, Acute; Leukocyte Elastase; Phosphatidylinositol 3-Kinases; Piperidines; Proto-Oncogene Proteins c-akt; Proto-Oncogene Proteins c-bcl-2; RNA Interference; RNA, Small Interfering; Signal Transduction; U937 Cells; Up-Regulation; bcl-2-Associated X Protein
PubMed: 26081156
DOI: 10.3892/mmr.2015.3946 -
Journal of Dairy Science May 2011α-Lactalbumin is a ubiquitous calcium-binding milk protein with a well-characterized function in regulating the synthesis of lactose. An entirely different activity has... (Comparative Study)
Comparative Study
α-Lactalbumin is a ubiquitous calcium-binding milk protein with a well-characterized function in regulating the synthesis of lactose. An entirely different activity has been shown to occur when a complex is formed between calcium-free α-lactalbumin and oleic acid. This complex shows strong cytotoxic action against several cancer cells, and several mechanisms have been suggested to account for this cell-killing activity. Most studies have been performed using the human protein, but bovine α-lactalbumin shows similar activity. A new and simple 2-step method for purification of calcium-free α-lactalbumin has been developed, and the resulting highly purified preparation was used to generate a complex with oleic acid. Using 3 different cell lines and 2 types of cell viability assays, the bovine and human α-lactalbumin showed comparable cytotoxic activity. The effect was apparent after 15 min of incubation and was inhibited by the presence of fetal bovine serum or bovine serum albumin. The bovine protein might be a useful alternative to the human protein, but also raises the question whether cytotoxic activity could be generated in different kinds of food containing α-lactalbumin.
Topics: Animals; Cattle; Cell Count; Cell Line, Tumor; Culture Media, Serum-Free; Cytotoxins; HL-60 Cells; Humans; Lactalbumin; Milk; Milk, Human; Oleic Acid; Oleic Acids; Serum; U937 Cells
PubMed: 21524506
DOI: 10.3168/jds.2010-3622 -
Journal of Immunology Research 2021We recently showed that both nontypeable (NTHi) and its surface plasminogen- (Plg-) binding proteins interact with lipoprotein(a) (Lp(a)) in a lysine-dependent manner....
We recently showed that both nontypeable (NTHi) and its surface plasminogen- (Plg-) binding proteins interact with lipoprotein(a) (Lp(a)) in a lysine-dependent manner. Because Lp(a) can be taken up by macrophages, we postulated that it serves as an opsonin to enhance phagocytosis of NTHi by macrophages. Based on colony-forming unit (CFU) counts, Lp(a) was found to increase U937 macrophage-mediated phagocytosis of NTHi49247 and NTHi49766 by 34% and 43%, respectively, after 120 min. In contrast, Lp(a) did not enhance phagocytosis of BL21 or JM109, which were unable to bind to Lp(a). As with U937 macrophages, Lp(a) was capable of increasing phagocytosis of NTHi49247 by peripheral blood mononuclear cell-derived macrophages. Opsonic phagocytosis by Lp(a) was inhibited by the addition of recombinant kringle IV type 10 (rKIV), a lysine-binding competitor; moreover, Lp(a) did not increase phagocytosis of NTHi by U937 macrophages that were pretreated with a monoclonal antibody against the scavenger receptor CD36. Taken together, our observation suggests that Lp(a) might serve as a lysine-binding opsonin to assist macrophages in rapid recognition and phagocytosis of NTHi.
Topics: CD36 Antigens; Cell Line; Cell Line, Tumor; Escherichia coli; Haemophilus Infections; Haemophilus influenzae; Humans; Leukocytes, Mononuclear; Lipoprotein(a); Macrophages; Opsonin Proteins; Phagocytosis; U937 Cells
PubMed: 34765679
DOI: 10.1155/2021/2185568 -
European Review For Medical and... Feb 2018To detect the expression of long non-coding RNA-CRNDE in patients with acute myeloid leukemia and its effect on proliferation and apoptosis in acute myeloid leukemia...
OBJECTIVE
To detect the expression of long non-coding RNA-CRNDE in patients with acute myeloid leukemia and its effect on proliferation and apoptosis in acute myeloid leukemia cell line U937.
PATIENTS AND METHODS
81 cases of newly diagnosed acute myeloid leukemia (AML) were enrolled, and 35 non-malignant hematological patients were selected as controls. Quantitative RT-PCR (qRT-PCR) was performed to detect the expression of lncRNA-CRNDE in the bone marrow specimens of the subjects, and the difference between the two groups was also compared. The correlation between the expression of lncRNA-CRNDE and the sex, age, classification and total survival of clinical patients was analyzed according to the clinical data. U937 cells and monocytes isolated from normal people were cultured, and the expression of lncRNA-CRNDE in acute myeloid leukemia cell line U937 and normal monocytes was compared. SiRNA-CRNDE and pcDNA-CRNDE were transfected into U937 cells, and cell counting kit-8 (CCK-8) assay was performed to detect proliferation of U937 cells, Annexin V/PI flow cytometry was carried out to detect cell apoptosis. Cell cycle was measured by flow cytometry.
RESULTS
The expression of lncRNA-CRNDE in patients with AML and U937 cells was significantly higher than that in non-malignant hematological controls. Results of clinical data showed that the expression of lncRNA-CRNDE was associated with the classification and total survival of myeloid leukemia in clinical patients. After transfection of siRNA-CRNDE, the proliferation and cloning ability of U937 cells decreased, while the apoptosis increased (p < 0.01) and cells were arrested in G0-G1 phase. Meanwhile, after transfection of pcDNA-CRNDE, the proliferation ability of U937 cells increased significantly, which indicated that the expression of lncRNA-CRNDE might play an essential role in promoting the proliferation of U937 cells.
CONCLUSIONS
LncRNA-CRNDE is highly expressed in the bone marrow tissues of AML patients, and the expression level is negatively correlated with the total survival of those clinical patients. Meanwhile, the expression is higher in FAB type M4 and M5 than that in M1, M2 and M3. LncRNA-CRNDE promotes the proliferation and cell cycle of U937 cells, and inhibits cell apoptosis, which is expected to become a molecular marker for predicting and treating AML.
Topics: Adolescent; Adult; Biomarkers, Tumor; Cell Line, Tumor; Cell Proliferation; Disease Progression; Female; Gene Expression Regulation, Neoplastic; Humans; Leukemia, Myeloid, Acute; Male; Middle Aged; RNA, Long Noncoding; Survival Rate; U937 Cells; Young Adult
PubMed: 29461608
DOI: 10.26355/eurrev_201802_14310 -
The Journal of Veterinary Medical... Jul 2020A 12-year-old female domestic short-haired cat was presented due to weight loss, anorexia, and tachypnea. Complete blood count revealed severe anemia, leukocytosis with...
A 12-year-old female domestic short-haired cat was presented due to weight loss, anorexia, and tachypnea. Complete blood count revealed severe anemia, leukocytosis with massive undifferentiated blast cells, and thrombocytopenia. Bone marrow aspiration showed acute myeloid leukemia, subclassified as monoblastic leukemia (M5a) based on the outcomes of the cytochemistry examinations. The SNAP feline leukemia virus (FeLV) and feline immunodeficiency virus (FIV) test using whole blood was negative. In addition, FeLV/FIV proviral polymerase chain reaction test using bone marrow aspirate was also negative. Although the cat was treated with doxorubicin, cytosine arabinoside, and prednisolone, anemia did not improve without blood transfusion. The owner declined further treatment after 2 months, and the cat died a few days later.
Topics: Animals; Antimetabolites, Antineoplastic; Antineoplastic Agents, Hormonal; Bone Marrow; Cat Diseases; Cats; Cytarabine; Doxorubicin; Female; Immunodeficiency Virus, Feline; Leukemia Virus, Feline; Leukemia, Monocytic, Acute; Prednisolone
PubMed: 32448817
DOI: 10.1292/jvms.20-0157 -
Clinical and Experimental Immunology Apr 2004IgA deposition in glomerular mesangium and the interaction with mesangial cells may well be the final common pathway to IgA nephropathy (IgAN). Altered hinge-region...
IgA deposition in glomerular mesangium and the interaction with mesangial cells may well be the final common pathway to IgA nephropathy (IgAN). Altered hinge-region O-glycosylation of IgA1 from patients with IgAN may predispose to mesangial deposition and activation of the mesangial cell (MC) by IgA1, via a novel IgA1 receptor, and may be a key event in the pathogensis of IgAN. The aim of this study was to investigate the binding capacity and biological effects of IgA1, from both patients with IgAN and healthy controls, on human mesangial cells (HMC). Serum IgA1 was isolated with jacalin affinity chromatography, heated to aggregated form (aIgA1) and labelled with (125)I. Binding capacity of aIgA1 in vitro to cultured primary HMC was evaluated by a radioligand binding assay and the specificity of binding was determined by a competitive inhibition assay. Intracellular calcium release was studied by confocal analysis and phosphorylation of extracellular signal-regulated kinase (ERK) was determined by Western blot analysis. Change of cell cycles was demonstrated by flow cytometry and HMC proliferation was evaluated by direct cell count. Expression of TGF-beta mRNA and production of supernatant fibronectin were tested by RT-PCR and indirect competitive ELISA, respectively. aIgA1 from both the patients with IgAN and normal controls bound to HMC in a dose-dependent, saturable manner, and was saturated at approximately 500 pmoles per 0.5 ml of aIgA1. aIgA1 from patients with IgAN, however, bound to HMC at a higher speed and Scatchard analysis revealed a Kd of (8.89 +/- 2.1) x 10(-8)m versus (4.3 +/- 1.2) x 10(-7)m for aIgA1 from healthy controls (P = 0.026). The binding was specific because it was only inhibited by unlabelled Mono-IgA1 (mIgA1) and not by serum albumin or IgG. aIgA1 from patients with IgAN could induce release of intracellular calcium, phosphorylation of ERK, DNA synthesis, proliferation of HMC, expression of TGF-betamRNA and secretion of fibronectin in HMC in a similar time-dependent manner as aIgA1 from healthy controls, but the effects were much stronger and the durations were much longer (P < 0.05, respectively). We conclude that aIgA1 from patients with IgAN has a higher binding capacity to HMC and stronger biological effects than aIgA1 from healthy controls. This suggests that direct interaction between IgA1 and HMC and subsequential pathophysiological responses may play an important role in the pathogenesis for IgAN.
Topics: Calcium; Cell Division; Cells, Cultured; DNA; Dose-Response Relationship, Immunologic; Fibronectins; Glomerular Mesangium; Glomerulonephritis, IGA; Humans; Immunoglobulin A; Mitogen-Activated Protein Kinases; Phosphorylation; RNA, Messenger; Signal Transduction; Transforming Growth Factor beta; U937 Cells; Up-Regulation
PubMed: 15030528
DOI: 10.1111/j.1365-2249.2004.02408.x