Chlamydia pneumoniae induces the expression of inhibitor of apoptosis 2 (c-IAP2) in a human monocytic cell line by an NF-kappaB-dependent pathway

Wahl, Christian; Maier, Sonja; Marre, R.; Essig, Andreas

doi:10.1078/1438-4221-00274

Cited by 34 publications

(27 citation statements)

References 19 publications

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“…The activation of NF-B in HUVECs is very fast, as it could be detected within 15 min of infection with C. pneumoniae (44). Similarly, in Mono Mac cells NF-B activation peaked within the first 60 min after infection (83,82). This strongly suggests that the intracellular signaling events leading to the translocation of NF-B are induced upon initial contact of the chlamydial particles with the eukaryotic cells.…”

Section: Discussionmentioning

confidence: 85%

“…Activation of NF-B during infection by C. pneumoniae has been described for a variety of different cell types (e.g., epithelial cells, HUVECs, human monocytes, and Mono Mac cells) (22,44,82,83). The activation of NF-B in HUVECs is very fast, as it could be detected within 15 min of infection with C. pneumoniae (44).…”

Section: Discussionmentioning

confidence: 99%

“…Indeed C. pneumoniae rGroEL1 initiates secretion of IL-12 and tumor necrosis factor via TLRs in dendritic cells and activates vascular endothelial cells to secrete the cytokines IL-1␤, IL-6, and IL-8 and to express cell surface adhesion proteins (12,51). Therefore, a feasible model is one in which surface localization of C. pneumoniae GroEL1 contributes to the pathogen-provoked activation of eukaryotic host cells upon chlamydial attachment and subsequently triggers the intracellular signal transduction pathways within the eukaryotic cells, as described by others (31,40,44,56,66,82,83). The nature of the GroEL1 receptor on the host cell is still unclear.…”

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confidence: 99%

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Chlamydia pneumoniaeGroEL1 Protein Is Cell Surface Associated and Required for Infection of HEp-2 Cells

Wuppermann¹,

Mölleken

Julien

et al. 2008

J Bacteriol

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Chlamydia pneumoniae is an important obligate intracellular pathogen that replicates within an inclusion in the eukaryotic cell. The initial event of a chlamydial infection is the adherence to and subsequent uptake of the infectious elementary bodies (EBs) by the human cell. These processes require yet-unidentified bacterial and eukaryotic surface proteins. The GroEL1 protein, which exhibits a very strong antigenicity and in vitro can activate various eukaryotic cells, is a potential pathogenicity factor. We localized the protein during the infection process and found it in the inclusion but outside the chlamydial particles. GroEL1 was also localized on the surface of EBs, and the protein could be washed off the EBs. Latex beads coated with recombinantly produced GroEL1 (rGroEL1) bound in a dose-dependent manner to HEp-2 cells. Likewise, GroEL1, when expressed and displayed on the yeast cell surface, mediated adhesion to HEp-2 cells. Interestingly, the homologous GroEL2 and GroEL3 proteins showed no adhesive properties. Incubation of primary umbilical vein endothelial cells with soluble GroEL1 and GroEL1-coated latex beads activated the translocation of the general transcription factor NF-B into the nucleus. Finally, preincubation of HEp-2 cells with rGroEL1 significantly reduced subsequent infection with C. pneumoniae, although adhesion of infectious bacteria to eukaryotic cells was not affected. Taken together, these data support a role for extracellular GroEL1 in the establishment of the chlamydial infection.

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Section: Discussionmentioning

confidence: 85%

Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

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Chlamydia pneumoniaeGroEL1 Protein Is Cell Surface Associated and Required for Infection of HEp-2 Cells

Wuppermann¹,

Mölleken

Julien

et al. 2008

J Bacteriol

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“…Several groups have reported that infection of epithelial cells by C. pneumoniae, C. trachomatis, and C. psittaci inhibits apoptosis induced by staurosporin or engagement of death receptors. This inhibitory effect appears to be mediated by stimulation of NFB activation, inhibition of cytochrome c release from mitochondria, and the subsequent inhibition of caspase activation (17,40,48,49). However, another recent study demonstrated that C. pneumoniae inhibition of apoptosis is not due to NFB-dependent factors (13).…”

Section: Discussionmentioning

confidence: 99%

Chlamydia pneumoniaeAugments the Oxidized Low-Density Lipoprotein-Induced Death of Mouse Macrophages by a Caspase-Independent Pathway

Yaraei¹,

Campbell²,

Zhu

et al. 2005

Infect Immun

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Chlamydia pneumoniae is a common respiratory pathogen that is associated with an increased risk of cardiovascular disease. However, the mechanisms by which C. pneumoniae contributes to cardiovascular disease have not been determined yet. C. pneumoniae infection may accelerate the death of cells within atherosclerotic lesions and contribute to the formation of unstable lesions. To test this hypothesis, the impact of C. pneumoniae infection on the death of lipid-loaded mouse macrophages was investigated. It was observed that RAW 264.7 cells are highly susceptible to the toxic effects of oxidized low-density lipoprotein (LDL) and exhibit markers of cell death within 24 h of treatment with as little as 5 g/ml oxidized LDL. Subsequent infection with either live C. pneumoniae or heat-killed or UV-inactivated C. pneumoniae at a low multiplicity of infection for 24 to 72 h stimulated both additional binding of annexin V and the uptake of propidium iodide. Thus, C. pneumoniae augments the effects of oxidized LDL on cell death independent of a sustained infection. However, unlike oxidized LDL, C. pneumoniae infection does not activate caspase 3 or induce formation of the mitochondrial transition pore or the fragmentation of DNA, all of which are classical markers of apoptosis. Furthermore, primary bone marrow macrophages isolated from mice deficient in Toll-like receptor 2 (TLR-2) but not TLR-4 are resistant to C. pneumoniae-induced death. These data suggest that C. pneumoniae kills cells by a caspase-independent pathway and that the process is potentially mediated by activation of TLR-2.

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“…C. pneumoniae promotes its entrance and/or its proliferation and persistence in host cells by enhancing NF-B activation (16); therefore, we speculate that inhibition of this transcription factor might explain, at least in part, the antichlamydial effects of glucocorticoids.…”

mentioning

confidence: 93%

Glucocorticoids Increase In Vitro and In Vivo Activities of Antibiotics against Chlamydophila pneumoniae

Caronzolo

Lucini

Pannacci

et al. 2004

Antimicrob Agents Chemother

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The in vitro and in vivo antichlamydial activities of dexamethasone and beclomethasone alone and in combination with an antibiotic were tested. In vitro, dexamethasone and beclomethasone decreased the number of inclusion-forming units versus the control number (P < 0.001). The combination of glucocorticoids with azithromycin, telithromycin, or levofloxacin was more active than antibiotics used alone (P < 0.001). The combination, tested in a murine Chlamydophila pneumoniae infection model, produced similar results.

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Chlamydia pneumoniae induces the expression of inhibitor of apoptosis 2 (c-IAP2) in a human monocytic cell line by an NF-kappaB-dependent pathway

Cited by 34 publications

References 19 publications

Chlamydia pneumoniaeGroEL1 Protein Is Cell Surface Associated and Required for Infection of HEp-2 Cells

Chlamydia pneumoniaeGroEL1 Protein Is Cell Surface Associated and Required for Infection of HEp-2 Cells

Chlamydia pneumoniaeAugments the Oxidized Low-Density Lipoprotein-Induced Death of Mouse Macrophages by a Caspase-Independent Pathway

Glucocorticoids Increase In Vitro and In Vivo Activities of Antibiotics against Chlamydophila pneumoniae

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