scholarly journals Infection of HeLa cells with Chlamydia trachomatis inhibits protein synthesis and causes multiple changes to host cell pathways

2019 ◽  
Vol 21 (4) ◽  
Author(s):  
Michaela Ohmer ◽  
Tina Tzivelekidis ◽  
Nora Niedenführ ◽  
Larisa Volceanov‐Hahn ◽  
Svenja Barth ◽  
...  
Keyword(s):  
Protein Synthesis ◽  
Chlamydia Trachomatis ◽  
Host Cell ◽  
Hela Cells

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 Poliovirus mutant that does not selectively inhibit host cell protein synthesis.

1985 ◽  
Vol 5 (11) ◽  
pp. 2913-2923 ◽  
Author(s):  
H D Bernstein ◽  
N Sonenberg ◽  
D Baltimore
Keyword(s):  
Protein Synthesis ◽  
Host Cell ◽  
Hela Cells ◽  
Mrna Translation ◽  
Selective Inhibition ◽  
Wild Type Virus ◽  
Progeny Virus ◽  
Wild Type ◽  
Amino Terminal ◽  
Translational Inhibition

A poliovirus type I (Mahoney strain) mutant was obtained by inserting three base pairs into an infectious cDNA clone. The extra amino acid encoded by the insertion was in the amino-terminal (protein 8) portion of the P2 segment of the polyprotein. The mutant virus makes small plaques on HeLa and monkey kidney (CV-1) cells at all temperatures. It lost the ability to mediate the selective inhibition of host cell translation which ordinarily occurs in the first few hours after infection. As an apparent consequence, the mutant synthesizes far less protein than does wild-type virus. In mutant-infected CV-1 cells enough protein was produced to permit a normal course of RNA replication, but the yield of progeny virus was very low. In mutant-infected HeLa cells there was a premature cessation of both cellular and viral protein synthesis followed by a premature halt of viral RNA synthesis. This nonspecific translational inhibition was distinguishable from wild-type-mediated inhibition and did not appear to be part of an interferon or heat shock response. Because the mutant is recessive, our results imply that (at least in HeLa cells) wild-type poliovirus not only actively inhibits translation of cellular mRNAs, but also avoids early inhibition of its own protein synthesis. Cleavage of the cap-binding complex protein P220, which has been associated with the selective inhibition of capped mRNA translation, did not occur in mutant-infected cells. This result supports the hypothesis that cleavage of P220 plays an important role in normal poliovirus-mediated translational inhibition.

scholarly journals Poliovirus mutant that does not selectively inhibit host cell protein synthesis

1985 ◽  
Vol 5 (11) ◽  
pp. 2913-2923 ◽  
Author(s):  
H D Bernstein ◽  
N Sonenberg ◽  
D Baltimore
Keyword(s):  
Protein Synthesis ◽  
Host Cell ◽  
Hela Cells ◽  
Mrna Translation ◽  
Selective Inhibition ◽  
Wild Type Virus ◽  
Progeny Virus ◽  
Wild Type ◽  
Amino Terminal ◽  
Translational Inhibition

A poliovirus type I (Mahoney strain) mutant was obtained by inserting three base pairs into an infectious cDNA clone. The extra amino acid encoded by the insertion was in the amino-terminal (protein 8) portion of the P2 segment of the polyprotein. The mutant virus makes small plaques on HeLa and monkey kidney (CV-1) cells at all temperatures. It lost the ability to mediate the selective inhibition of host cell translation which ordinarily occurs in the first few hours after infection. As an apparent consequence, the mutant synthesizes far less protein than does wild-type virus. In mutant-infected CV-1 cells enough protein was produced to permit a normal course of RNA replication, but the yield of progeny virus was very low. In mutant-infected HeLa cells there was a premature cessation of both cellular and viral protein synthesis followed by a premature halt of viral RNA synthesis. This nonspecific translational inhibition was distinguishable from wild-type-mediated inhibition and did not appear to be part of an interferon or heat shock response. Because the mutant is recessive, our results imply that (at least in HeLa cells) wild-type poliovirus not only actively inhibits translation of cellular mRNAs, but also avoids early inhibition of its own protein synthesis. Cleavage of the cap-binding complex protein P220, which has been associated with the selective inhibition of capped mRNA translation, did not occur in mutant-infected cells. This result supports the hypothesis that cleavage of P220 plays an important role in normal poliovirus-mediated translational inhibition.

scholarly journals Fusion of Chlamydia trachomatis-Containing Inclusions Is Inhibited at Low Temperatures and Requires Bacterial Protein Synthesis

1998 ◽  
Vol 66 (11) ◽  
pp. 5364-5371 ◽  
Author(s):  
Christiaan Van Ooij ◽  
Ellen Homola ◽  
Eleanor Kincaid ◽  
Joanne Engel
Keyword(s):  
Protein Synthesis ◽  
Chlamydia Trachomatis ◽  
Host Cell ◽  
Host Cells ◽  
Bacterial Protein ◽  
Cell Cytoplasm ◽  
Mammalian Cell Lines ◽  
Host Cell Cytoplasm ◽  
Early Endosomes ◽  
Bacterial Protein Synthesis

ABSTRACT The human pathogen Chlamydia trachomatis is an obligate intracellular bacterium with a unique developmental cycle. Within the host cell cytoplasm, it resides within a membrane-bound compartment, the inclusion. A distinguishing characteristic of the C. trachomatis life cycle is the fusion of the chlamydia-containing inclusions with each other in the host cell cytoplasm. We report that fusion of inclusions does not occur at 32°C in multiple mammalian cell lines and with three different serovars of C. trachomatis. The inhibition of fusion was inclusion specific; the fusion with sphingolipid-containing secretory vesicles and the interaction with early endosomes were unaffected by incubation at 32°C. The inhibition of fusion of the inclusions was not primarily the result of delayed maturation of the inclusion, as infectious progeny was produced in host cells incubated at 32°C, and the unfused inclusions remained competent to fuse up to 48 h postinfection. The ability to reverse the inhibition of fusion by shifting the infected cells from 32 to 37°C allowed the measurement of the rate and the time of fusion of the inclusions after entry of the bacteria. Most significantly, we demonstrate that fusion of inclusions with each other requires bacterial protein synthesis and that the required bacterial protein(s) is present, but inactive or not secreted, at 32°C.

scholarly journals Origin of the Eukaryotic Cell

2017 ◽  
Vol 01 (02) ◽  
pp. 108-120 ◽  
Author(s):  
Nick Lane
Keyword(s):  
Protein Synthesis ◽  
Host Cell ◽  
Genome Size ◽  
Energy Savings ◽  
Nuclear Genome ◽  
Eukaryotic Cell ◽  
Eukaryotic Cells ◽  
Bacterial Genomes ◽  
Complex Cells ◽  
Life On Earth

All complex life on Earth is composed of ‘eukaryotic’ cells. Eukaryotes arose just once in 4 billion years, via an endosymbiosis — bacteria entered a simple host cell, evolving into mitochondria, the ‘powerhouses’ of complex cells. Mitochondria lost most of their genes, retaining only those needed for respiration, giving eukaryotes ‘multi-bacterial’ power without the costs of maintaining thousands of complete bacterial genomes. These energy savings supported a substantial expansion in nuclear genome size, and far more protein synthesis from each gene.

scholarly journals Recruitment of BAD by the Chlamydia trachomatis Vacuole Correlates with Host-Cell Survival

2006 ◽  
Vol 2 (5) ◽  
pp. e45 ◽  
Author(s):  
Philippe Verbeke ◽  
Lynn Welter-Stahl ◽  
Songmin Ying ◽  
Jon Hansen ◽  
Georg Häcker ◽  
...  
Keyword(s):  
Chlamydia Trachomatis ◽  
Cell Survival ◽  
Host Cell
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