scholarly journals Role of High-Mobility Group Box 1 Protein and Poly(ADP-Ribose) Polymerase 1 Degradation in Chlamydia trachomatis-Induced Cytopathicity

2010 ◽  
Vol 78 (7) ◽  
pp. 3288-3297 ◽  
Author(s):  
Hangxing Yu ◽  
Katja Schwarzer ◽  
Martin Förster ◽  
Olaf Kniemeyer ◽  
Vera Forsbach-Birk ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Cell Membrane ◽  
Hela Cells ◽  
High Mobility ◽  
Host Cells ◽  
High Mobility Group ◽  
Cell Membrane Permeability ◽  
Dependent Manner ◽  
Infected Cells ◽  
Parp 1

ABSTRACT As intracellular bacteria, chlamydiae block the apoptotic pathways of their host cells. However, the infection of epithelial cells causes the loss of cell membrane integrity and can result in nonapoptotic death. Normally, cells undergoing necrosis release high-mobility group box 1 protein (HMGB1) that acts as an important proinflammatory mediator. Here, we show that in Chlamydia trachomatis-infected HeLa cells HMGB1 is not translocated from the nucleus to the cytosol and not released from injured cells in increased amounts. At 48 h after infection, degradation of HMGB1 was observed. In infected cells, poly(ADP-ribose) polymerase 1 (PARP-1), a DNA repair enzyme that also regulates HMGB1 translocation, was found to be cleaved into fragments that correspond to a necrosislike pattern of PARP-1 degradation. Cell-free cleavage assays and immunoprecipitation using purified proteolytic fractions from infected cells demonstrated that the chlamydial-protease-like activity factor (CPAF) is responsible for the cleavage of both HMGB1 and PARP-1. Proteolytic cleavage of PARP-1 was accompanied by a significant decrease in the enzymatic activity in a time-dependent manner. The loss of PARP-1 function obviously affects the viability of Chlamydia-infected cells because silencing of PARP-1 in uninfected HeLa cells with specific small interfering RNA results in increased cell membrane permeability. Our findings suggest that the Chlamydia-specific protease CPAF interferes with necrotic cell death pathways. By the degradation of HMGB1 and PARP-1, the pathogen may have evolved a strategy to reduce the inflammatory response to membrane-damaged cells in vivo.

scholarly journals Persistent Chlamydia trachomatis Infection of HeLa Cells Mediates Apoptosis Resistance through a Chlamydia Protease-Like Activity Factor-Independent Mechanism and Induces High Mobility Group Box 1 Release

2011 ◽  
Vol 80 (1) ◽  
pp. 195-205 ◽  
Author(s):  
Jürgen Rödel ◽  
Christina Große ◽  
Hangxing Yu ◽  
Katharina Wolf ◽  
Gordon P. Otto ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Host Cell ◽  
Hela Cells ◽  
Persistent Infection ◽  
High Mobility ◽  
Apoptosis Resistance ◽  
Content Type ◽  
Activity Factor ◽  
Infected Cells ◽  
Ifn Γ

ABSTRACTIntracellular persistence ofChlamydia trachomatishas been implicated in the development of chronic infection that can result in pelvic inflammatory disease and tubal sterility. By inhibition of host cell apoptosis, chlamydiae have evolved a strategy to maintain the intracellular environment for replication and persistence. Both antiapoptotic host cell-derived factors and the chlamydial protease-like activity factor (CPAF) are involved inChlamydia-mediated apoptosis resistance. Here, we show that in HeLa cells infected with gamma interferon (IFN-γ)-induced persistentC. trachomatisserovar D, the expression of CPAF is downregulated, and proapoptotic protease substrates are not cleaved. Persistent infection protected HeLa cells from apoptosis when they were exposed to staurosporine. Small-interfering RNA-mediated inhibition of myeloid cell leukemia 1 (Mcl-1) protein upregulation sensitized persistently infected cells for apoptosis. The inhibitor of apoptosis protein 2 (IAP-2) seems not to be relevant in this context because IAP-2 protein was not induced in response to IFN-γ treatment. Although apoptosis was inhibited, persistent infection caused cell membrane disintegration, as measured by the increased release of cytokeratin 18 from HeLa cells. Moreover, persistently infected cells released significantly increased amounts of high mobility group box 1 (HMGB1) protein which represents a proinflammatory damage-associated pattern molecule. The data of this study suggest that cells infected with persistentC. trachomatisare protected from apoptosis independently of CPAF but may promote chronic inflammation through HMGB1 release.

scholarly journals High Mobility Group Box 1: a Novel Host Restriction Factor in Zika Virus Replication

2021 ◽  
Author(s):  
Kim-Ling Chin ◽  
Nurhafiza binti Zainal ◽  
Sing-Sin Sam ◽  
Pouya Hassandarvish ◽  
Rafidah Lani ◽  
...  
Keyword(s):  
Zika Virus ◽  
Severe Disease ◽  
High Mobility ◽  
High Mobility Group ◽  
Enzyme Linked Immunosorbent Assay ◽  
Dependent Manner ◽  
Zikv Infection ◽  
Hmgb1 Level ◽  
Antiviral Effects ◽  
Huh7 Cells

Abstract Neonatal microcephaly and adult Guillain-Barré syndrome are severe complications of Zika virus (ZIKV) infection. The robustly induced inflammatory cytokine expressions in ZIKV-infected patients may constitute a hallmark for severe disease. In the present study, the potential role of high mobility group box 1 protein (HMGB1) in ZIKV infection was investigated. HMGB1 protein expression was determined by the enzyme-linked immunosorbent assay (ELISA) and immunoblot assay. HMGB1’s role in ZIKV infection was also explored using treatment with dexamethasone, an immunomodulatory drug. Antiviral effects of dexamethasone treatment on both wild-typed (WT) and HMGB1-knockdown (shHMGB1) Huh7 cells were determined by the focus-forming assay. Results showed that the Huh7 cells were highly susceptible to ZIKV infection. The infection was found to induce HMGB1 nuclear-to-cytoplasmic translocation, resulting in a >99% increase in the cytosolic HMGB1 expression at 72h.p.i. The extracellular HMGB1 level was elevated in a time- and multiplicity of infection (MOI)- dependent manner. Dexamethasone 150 µM treatment of the ZIKV-infected cells reduced HMGB1 extracellular release in a dose-dependent manner, with a maximum reduction of 71 ± 5.84% (p < 0.01). The treatment also reduced virus titers by over 83 ± 0.50% (p < 0.01). The antiviral effects, however, was not observed in the dexamethasone-treated HMGB1-knockdown cells, suggesting the importance of the intracellular HMGB1 in ZIKV infection. Overall, these results suggest that translocation of HMGB1 occurred during ZIKV infection and inhibition of the translocation reduced ZIKV replication. These findings highlight the potential of developing therapeutics against ZIKV infection by affecting the translocation of HMGB1 from the nucleus to the cytoplasm.

scholarly journals Identification of differentially expressed circular RNAs in HeLa cells infected with Chlamydia trachomatis

2019 ◽  
Vol 77 (7) ◽  
Author(s):  
Yuanjun Liu ◽  
Chunmin Hu ◽  
Yina Sun ◽  
Haoqing Wu ◽  
Xiaojun Chen ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Signaling Pathways ◽  
Hela Cells ◽  
Expression Profiles ◽  
Quantitative Polymerase Chain Reaction ◽  
Host Cells ◽  
Differentially Expressed ◽  
Chlamydia Infection ◽  
Circular Rnas ◽  
Mrna Microarray

ABSTRACT Non-coding circular RNAs (circRNAs) have been shown to have important roles in many diseases; however, no study has indicated circRNAs are involved in Chlamydia trachomatis infection. In this study, we used circRNA microarray to measure the global circRNA expression profiles in HeLa cells with or without C. trachomatis serovar E (Ct.E) infection. CircRNA/miRNA/mRNA interactions were predicted and bioinformatics analyses were performed. The differentially expressed circRNAs were selected according to our criterion for validation by reverse-transcription and quantitative polymerase chain reaction (RT-qPCR). The mRNA microarray was used to detect the mRNA expression profiles after Ct.E infection. Among 853 differentially expressed circRNAs, 453 were upregulated and 400 were downregulated after Ct.E infection. Target miRNAs and miRNA-targeted mRNAs of these circRNAs were predicted. RT-qPCR analysis indicated hsa_circRNA_001226, hsa_circRNA_007046 and hsa_circRNA_400027 were elevated similar to those determined in the circRNA microarray analysis. The mRNA microarray results showed 915 genes were upregulated and 619 genes were downregulated after Ct.E infection. Thirty-four differentially expressed genes overlapped in the bioinformatics and mRNA microarray results. KEGG pathway analysis revealed several signaling pathways, including endocytosis, MAPK and PI3P-Akt signaling pathways, that were targeted by circRNAs may play important roles in Chlamydia infection. This study provides evidence that circRNAs in host cells are involved in the process of Chlamydia infection.

scholarly journals Salvianolic acid B protects against myocardial ischaemia-reperfusion injury in rats via inhibiting high mobility group box 1 protein expression through the PI3K/Akt signalling pathway

2019 ◽  
Vol 393 (8) ◽  
pp. 1527-1539 ◽  
Author(s):  
Hanqing Liu ◽  
Wei Liu ◽  
Huiliang Qiu ◽  
Dezhi Zou ◽  
Huayang Cai ◽  
...  
Keyword(s):  
Cardiac Function ◽  
Myocardial Ischaemia ◽  
Myocardial Injury ◽  
High Mobility ◽  
Salvianolic Acid B ◽  
High Mobility Group ◽  
High Dose ◽  
Dependent Manner ◽  
Salvianolic Acid ◽  
Ischaemia Reperfusion

AbstractSalvianolic acid B (Sal B) has a significant protective effect on myocardial ischaemia-reperfusion (I/R) injury. Therefore, the aims of this study were to determine the effects of Sal B on myocardial ischaemic-reperfusion (I/R) injury in rats and to explore whether its underlying mechanism of cardioprotection occurs through activating the expression of the phosphoinositide 3-kinase/protein, kinase B (PI3K/Akt) and inhibiting the expression of high mobility group protein 1 (HMGB1). Ninety Sprague-Dawley rats were randomized into five groups: group 1 (sham-operated), group 2 (myocardial I/R), group 3 (low dose of Sal B+I/R), group 4 (high dose of Sal B+I/R), and group 5 (high dose of Sal B+I/R+LY294002, which is a specific PI3k inhibitor). All I/R rats received 30 min myocardial ischaemia followed by 24-h reperfusion. Cardiac function, infarct size, myocardial injury marker levels, inflammatory response and cardiomyocyte apoptosis as well as Bcl-2, Bax, P-Akt, HMGB1 and TLR4 expression were measured. In the current study, Sal B significantly ameliorated myocardial I/R injury in a dose-dependent manner, ameliorated cardiac function, reduced myocardial infarction size, decreased myocardial injury marker expression, decreased inflammatory responses, reduced apoptosis, activated PI3K/Akt expression and inhibited HMGB1 expression. However, all effects of Sal B were significantly reversed by LY294002. Overall, the present study indicated that Sal B attenuated myocardial I/R injury by activating PI3K/Akt and inhibiting the release of HMGB1 in rats.

Glucose-restriction increasesTrichomonas vaginaliscellular damage towards HeLa cells and proteolytic activity of cysteine proteinases (CPs), such as TvCP2

Parasitology ◽  
2019 ◽  
Vol 146 (9) ◽  
pp. 1156-1166 ◽  
Author(s):  
Jesús F. T. Miranda-Ozuna ◽  
Luis Alberto Rivera-Rivas ◽  
Rosa Elena Cárdenas-Guerra ◽  
Mar Sarai Hernández-García ◽  
Sarahí Rodríguez-Cruz ◽  
...  
Keyword(s):  
Proteolytic Activity ◽  
Hela Cells ◽  
Trichomonas Vaginalis ◽  
Host Cells ◽  
Cellular Damage ◽  
Dependent Manner ◽  
Concentration Dependent Manner ◽  
Cell Monolayers ◽  
Glucose Restriction ◽  
Effect Of Glucose

AbstractTrichomonas vaginalisinduces cellular damage to the host cells (cytotoxicity) through the proteolytic activity of multiple proteinases of the cysteine type (CPs). Some CPs are modulated by environmental factors such as iron, zinc, polyamines, etc. Thus, the goal of this study was to assess the effect of glucose onT. vaginaliscytotoxicity, proteolytic activity and the particular role of TvCP2 (TVAG_057000) during cellular damage. Cytotoxicity assays showed that glucose-restriction (GR) promotes the highest HeLa cell monolayers destruction (~95%) by trichomonads compared to those grown under high glucose (~44%) condition. Zymography and Western blot using different primary antibodies showed that GR increased the proteolytic activity, amount and secretion of certain CPs, including TvCP2. We further characterized the effect of glucose on TvCP2. TvCP2 increases in GR, localized in vesicles close to the plasma membrane and on the surface ofT. vaginalis. Furthermore, pretreatment of GR-trichomonads with an anti-TvCP2r polyclonal antibody specifically reduced the levels of cytotoxicity and apoptosis induction to HeLa cells in a concentration-dependent manner. In conclusion, our data show that GR, as a nutritional stress condition, promotes trichomonal cytotoxicity to the host cells, increases trichomonad proteolytic activity and amount of CPs, such as TvCP2 involved in cellular damage.

scholarly journals High-mobility group box-1 as an autocrine trophic factor in white matter stroke

2017 ◽  
Vol 114 (25) ◽  
pp. E4987-E4995 ◽  
Author(s):  
Jun Young Choi ◽  
Yuexian Cui ◽  
Samma Tasneem Chowdhury ◽  
Byung Gon Kim
Keyword(s):  
White Matter ◽  
Signaling Pathways ◽  
High Mobility ◽  
Glucose Deprivation ◽  
High Mobility Group ◽  
Dependent Manner ◽  
Protective Effects ◽  
Tlr2 Ligand ◽  
Health And Disease ◽  
Trophic Signaling

Maintenance of white matter integrity in health and disease is critical for a variety of neural functions. Ischemic stroke in the white matter frequently results in degeneration of oligodendrocytes (OLs) and myelin. Previously, we found that toll-like receptor 2 (TLR2) expressed in OLs provides cell-autonomous protective effects on ischemic OL death and demyelination in white matter stroke. Here, we identified high-mobility group box-1 (HMGB1) as an endogenous TLR2 ligand that promotes survival of OLs under ischemic stress. HMGB1 rapidly accumulated in the culture medium of OLs exposed to oxygen–glucose deprivation (OGD). This conditioned medium exhibited a protective activity against ischemic OL death that was completely abolished by immunodepletion of HMGB1. Knockdown of HMGB1 or application of glycyrrhizin, a specific HMGB1 inhibitor, aggravated OGD-induced OL death, and recombinant HMGB1 application reduced the extent of OL death in a TLR2-dependent manner. We confirmed that cytosolic translocation of HMGB1 and activation of TLR2-mediated signaling pathways occurred in a focal white matter stroke model induced by endothelin-1 injection. Animals with glycyrrhizin coinjection showed an expansion of the demyelinating lesion in a TLR2-dependent manner, accompanied by aggravation of sensorimotor behavioral deficits. These results indicate that HMGB1/TLR2 activates an autocrine trophic signaling pathways in OLs and myelin to maintain structural and functional integrity of the white matter under ischemic conditions.

scholarly journals High-mobility group box 1 protein induces tissue factor expression in vascular endothelial cells via activation of NF-κB and Egr-1

2009 ◽  
Vol 102 (08) ◽  
pp. 352-359 ◽  
Author(s):  
Haichao Wang ◽  
Yiting Tang ◽  
Zhang Fan ◽  
Ben Lv ◽  
Xianzhong Xiao ◽  
...  
Keyword(s):  
Endothelial Cells ◽  
Cell Surface ◽  
Tissue Factor ◽  
Vascular Endothelial Cells ◽  
High Mobility ◽  
High Mobility Group ◽  
Cell Surface Receptors ◽  
Dependent Manner ◽  
Vascular Endothelial ◽  
Surface Receptors

SummaryHigh-mobility group box 1 protein (HMGB1), an abundant nuclear protein, was recently established as a proinflammatory mediator of experimental sepsis.Although extracellular HMGB1 has been found in atherosclerotic plaques, its potential role in the pathogenesis of atherothrombosis remains elusive. In the present study, we determined whether HMGB1 induces tissue factor (TF) expression in vascular endothelial cells (ECs) and macrophages. Our data showed that HMGB1 stimulated ECs to express TF (but not TF pathway inhibitor) mRNA and protein in a concentration and time-dependent manner. Blockade of cell surface receptors (including TLR4, TLR2, and RAGE) with specific neutralising antibodies partially reduced HMGB1-induced TF expression. Moreover, HMGB1 increased expression of Egr-1 and nuclear translocation of NF-κB (c-Rel/p65) in ECs. Taken together, our data suggest that HMGB1 induces TF expression in vascular endothelial cells via cell surface receptors (TLR4, TLR2, and RAGE), and through activation of transcription factors (NF-κB and Egr-1).

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