Ontology highlight
ABSTRACT:
PROVIDER: PRJNA1321310 | ENA |
REPOSITORIES: ENA
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Project description:Chlamydiae are obligate intracellular bacteria that inhibit mitochondrial apoptosis to maintain integrity of the host cell. We have previously reported that a chlamydial outer membrane b-barrel protein, OmpA, can during ectopic expression inhibit mitochondrial apoptosis through direct interaction with the BCL-2-family effectors BAX and BAK. We here show that OmpA from Chlamydia trachomatis (Ctr) uses membrane vesicles for its delivery to the outer mitochondrial membrane during Ctr infection. Using a number of imaging and fractionation techniques, we show that OmpA during infection reaches mitochondria and is inserted into mitochondrial membranes. Chlamydia derived vesicles (CDV) from Ctr-infected cells contained OmpA as well as other outer membrane proteins and LPS. When added to uninfected cells, CDVs fused with mitochondrial membranes, causing the interaction of OmpA with BAK and the cytosolic retro-translocation of BAX. CDV addition to uninfected cells also protected the cells against apoptosis. We previously showed tha OmpA works in co-ordination with VDAC2 to block apoptosis and here propose a structural model of this BAK inhibition by OmpA that reenacts the inhibition of BAK by VDAC2. The results provide evidence that OmpA from Chlamydia, as well as the structurally similar ortholog from the related Simkania, specifically exploits its relationship to mitochondrial porins to protect the infected cell against apoptosis and to enable intracellular growth of the bacteria in human cells.
2025-11-18 | MSV000099942 | MassIVE
Project description:This work describes the development of the first microarray detection system that simultaneously identifies common pathogens associated with STDs from clinical samples, and paves the way for establishing a time-saving, accurate and high-throughput diagnostic tool. The target genes are 16S rRNA gene for N. gonorrhoeae, M. genitalium, M. hominism, and Ureaplasma, the major outer membrane protein gene (ompA) for C. trachomatis, the glycoprotein B gene (gB) for HSV; and the L1 gene for HPV. 34 probes that reproducibly detected multiple Legionella species with high specificity were included in the array.
2015-12-31 | E-GEOD-69508 | biostudies-arrayexpress
Project description:Many infectious agents have the need to inhibit host apoptosis, and various strategies are known. Chlamydia trachomatis is an obligate intracellular bacterium replicating in a vacuole in the human cytosol. Chlamydia-infected human cells are strongly protected against apoptosis. We here mapped this anti-apoptotic activity to the direct blockade of the effectors of mitochondrial apoptosis, the Bcl-2-family proteins Bax and Bak. Molecular analysis of Bak revealed the inhibition of activation-associated conformational changes by the infection. Surprisingly, we identified the C. trachomatis outer membrane porin OmpA in a complex with Bak on mitochondria. When expressed in uninfected human cells, OmpA was imported into mitochondrial membranes. OmpA alone blocked apoptosis and reproduced the changes to Bak-activation observed during infection, reminiscent of the established activity of the human mitochondrial porin, VDAC2. The results suggest that C. trachomatis utilizes the relationship between gram-negative bacteria and mitochondria to block apoptosis and to secure its intracellular growth.
2026-01-26 | PXD011848 | Pride
Project description:To understand the changes in gene expression by oral immunotherapy to a multi-antigenic construct consisting AHC (ApoB, HSP60 and chlamydia pneumonia outer membrane protein) at different stages of atherosclerotic development, double knock out Apobtm2Sgy/Ldltm1Her mice were fed with high-fat after 5 oral doses with respective highfat diet alone controls at 0,6,18 and 30 weeks.
2022-08-31 | GSE110670 | GEO
Project description:OmpA, a predominant outer membrane protein (OMP) in Gram-negative bacteria, plays a crucial role in maintaining the integrity and functionality of the bacterial outer membrane (OM). Despite its significance in virulence, adhesion, and OM stability, the specific role of OmpA has remained unclear since its discovery 50 years ago. In this study, we demonstrate that OmpA organizes the OMP lattice and mechanically connects it to the cell wall. Using atomic force microscopy, simulations, and microfluidics, we show that while the β-barrel domain of OmpA is essential for maintaining the permeability barrier, both the β-barrel and cell wall-binding domains are necessary to enhance the cell envelope's strength. We propose that OmpA integrates the compressive properties of the OMP lattice with the tensile strength of the cell wall, forming a mechanically robust composite that enhances overall envelope integrity. This coupling likely underpins the ability of the entire envelope to function as a cohesive and resilient structure, critical for the survival and pathogenicity of Gram-negative bacteria.
2024-11-20 | PXD054033 | Pride
Project description:Escherichia coli is a major cause of blood stream and urinary tract infections. Owing to the spread of antimicrobial resistance, it is often treated with an inadequate antibiotic. With the aim to accelerate the diagnostics of this key pathogen, we used the flycode technology to generate nanobodies against the conserved and highly abundant outer membrane protein OmpA. Two nanobodies each recognizing a different isoform of OmpA were shown by flow cytometry to recognize > 91% of 85,680 E. coli OmpA sequences deposited in a large bacterial genome database. Crystal structures of these nanobodies in complex with the respective OmpA isoform revealed interactions with all four surface accessible loops of OmpA. Steric hindrance caused by dense O-antigen layers initially impeded reliable capture of clinical E. coli strains. By generating nanobody constructs with long linkers and by thinning the O-antigen layer through alterations to growth medium and buffers, we achieved to capture <50 CFU/mL. Our work provides a framework to generate nanobodies for the specific and sensitive detection and capture of clinically relevant pathogenic bacteria.
2025-06-11 | PXD054264 | Pride