An epistatic effect of apaf - 1 and caspase - 9 on chlamydial infection

Abstract Chlamydia is an obligate intracellular bacterial pathogen that replicates solely within a membrane-bound vacuole termed an inclusion. Chlamydia seems to perturb multiple cellular processes of the host, such as, rearrangement of the membrane trafficking system for its intracellular multiplication, and inhibition of host cell apoptosis for persistent infection. In an attempt to clarify host factor involvement in apoptosis regulation, we found that inhibition of Caspase-9 restricted, while Apaf-1 promoted, Chlamydia pneumoniae infection in HEp-2, HeLa, and mouse epithelial fibroblast (MEF) cells. These opposition contributions to the chlamydial infection were confirmed using caspase-9 −/− and apaf-1 −/− MEFs. Similar phenomena also appeared in the case of infection with Chlamydia trachomatis. Interestingly, caspase-9 in apaf-1 −/− MEFs was activated by chlamydial infection but during the infection caspase-3 was not activated. That is, caspase-9 was activated without support for multiplication and activation by Apaf-1, and the activated caspase-9 may be physically disconnected from the caspase cascade. This may be partially explained by the observation of caspase-9 accumulation within chlamydial inclusions. The sequestration of caspase-9 by chlamydia seems to result in apoptosis repression, which is crucial for the chlamydial development cycle. Because Apaf-1 shares doma...
Source: Apoptosis - Category: Molecular Biology Source Type: research

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Publication date: Available online 31 May 2020Source: Comparative Immunology, Microbiology and Infectious DiseasesAuthor(s): Aymen Mamlouk, Kaouther Guesmi, Imen Ouertani, Sana Kalthoum, Rachid Selmi, Elhem Ben Aicha, Bassem Bel Haj Mohamed, Raja Gharbi, Monia Lachtar, Anissa Dhaouadi, Chedia Seghaier, Lilia Messadi
Source: Comparative Immunology, Microbiology and Infectious Diseases - Category: Infectious Diseases Source Type: research
Conclusion: The incidence of C. trachomatis infection in the endocervical samples from these women can be considered high, which emphasizes the importance of measures designed to clarify and prevent this important STI.RESUMEN Introducci ón: Chlamydia trachomatis es uno de los principales agentes causantes de infecciones de transmisión sexual (ITS) en hombres y mujeres, pero el mayor impacto de la infección se produce en el aparato reproductor de las mujeres, causando, entre otros problemas, infertilidad. Objetivo: Calcular la incidencia de C. trachomatis detectada por la técnica de reacció...
Source: Jornal Brasileiro de Patologia e Medicina Laboratorial - Category: Pathology Source Type: research
Publication date: Available online 19 May 2020Source: The Brazilian Journal of Infectious DiseasesAuthor(s): Maria-Francesca Manca, Laurence Rochat-Stettler, Jean-François Carod, Camille Agostini, Anne Jolivet
Source: The Brazilian Journal of Infectious Diseases - Category: Infectious Diseases Source Type: research
Publication date: Available online 19 May 2020Source: The Brazilian Journal of Infectious DiseasesAuthor(s): Maria-Francesca Manca, Laurence Rochat Stettler, Jean-François Carod, Camille Agostini, Anne Jolivet
Source: The Brazilian Journal of Infectious Diseases - Category: Infectious Diseases Source Type: research
Publication date: Available online 19 May 2020Source: Microbes and InfectionAuthor(s): Jeewan Thapa, Kent Hashimoto, Saori Sugawara, Ryoya Tsujikawa, Torahiko Okubo, Shinji Nakamura, Hiroyuki Yamaguchi
Source: Microbes and Infection - Category: Infectious Diseases Source Type: research
Publication date: 19 May 2020Source: Cell Reports, Volume 31, Issue 7Author(s): Audrey Xavier, Munir A. Al-Zeer, Thomas F. Meyer, Oliver Daumke
Source: Cell Reports - Category: Cytology Source Type: research
A new 30-minute point-of-care test using self-collected vaginal swabs works as well as lab-based molecular diagnostic tests for detecting chlamydia and gonorrhea, new findings show.Reuters Health Information
Source: Medscape Pathology Headlines - Category: Pathology Tags: Family Medicine/Primary Care News Source Type: news
In this study, we attempted to explore the role of the only secreted plasmid-encoded protein pORF5 of C. trachomatis between UPR and autophagy induction. The results showed that three branches of UPR (PERK, IRE1, and ATF6) were activated by pORF5. pORF5-induced autophagy was repressed by UPR inhibitors GSK2606414 and 4μ8C, while the autophagy inhibition was failed to influence pORF5-induced UPR significantly. MAPK/ERK inhibitor PD98059 partially suppressed the pORF5-induced autophagy, but had little effect on UPR, indicating that pORF5 actives UPR to induce autophagy via the MAPK/ERK signaling pathway. These observ...
Source: Biochemical and Biophysical Research communications - Category: Biochemistry Authors: Tags: Biochem Biophys Res Commun Source Type: research
The cryptic plasmid pCM is critical for chlamydial colonization in the gastrointestinal tract. Nevertheless, orally inoculated plasmid-free Chlamydia sp. was still able to colonize the gut. Surprisingly, orally inoculated Chlamydia sp. deficient in only plasmid-encoded pGP3 was no longer able to colonize the gut. A comparison of live organism recoveries from individual gastrointestinal tissues revealed that pGP3-deficient Chlamydia sp. survived significantly better than plasmid-free Chlamydia sp. in small intestinal tissues. However, the small intestinal pGP3-deficient Chlamydia sp. failed to reach the large intestine, exp...
Source: Infection and Immunity - Category: Infectious Diseases Authors: Tags: Host-Associated Microbial Communities Source Type: research
Apoptotic cell death can be an efficient defense reaction of mammalian cells infected with obligate intracellular pathogens; the host cell dies and the pathogen cannot replicate. While this is well established for viruses, there is little experimental support for such a concept in bacterial infections. All Chlamydiales are obligate intracellular bacteria, and different species infect vastly different hosts. Chlamydia trachomatis infects human epithelial cells; Parachlamydia acanthamoebae replicates in amoebae. We here report that apoptosis impedes growth of P. acanthamoebae in mammalian cells. In HeLa human epithelial cell...
Source: Infection and Immunity - Category: Infectious Diseases Authors: Tags: Cellular Microbiology: Pathogen-Host Cell Molecular Interactions Source Type: research
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