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ANALYSIS OF MITOCHONDRIAL RE-LOCALIZATION IN CHLAMYDIA TRACHOMATIS INFECTION
Title
ANALYSIS OF MITOCHONDRIAL RE-LOCALIZATION IN CHLAMYDIA TRACHOMATIS INFECTION
Creator
Patel, Dhwani B.
Date
2017, 2017-05
Description
Chlamydia trachomatis is an obligate intracellular parasite that causes eye and genital tract infection in humans. C. trachomatis genital...
Show moreChlamydia trachomatis is an obligate intracellular parasite that causes eye and genital tract infection in humans. C. trachomatis genital tract infection is one of the most prevalent sexually transmitted diseases in United States. This pathogenic bacterium depends on the host cell for essential metabolites for energy generation and ATP as readily available energy source. Several previous studies have established interactions between the chlamydial inclusion and various host cell organelles, including the Golgi complex, nutrient rich exocytic vesicles and the cytoskeleton for survival in the host cell. However, the data available for chlamydial interactions with mitochondria is limited. In order to gain proper understanding of the host- pathogen relationship, the chlamydial inclusion interaction with mitochondria were evaluated, using HeLa cells as host. Immunostaining technique was used to stain uninfected and C. trachomatis (serovar L2b) infected HeLa cells at 7 different time points post infection- 8, 10, 12, 16, 18, 24, 36 hour post infection (hpi) and analyzed by fluorescence microscopy. The data showed that the chlamydial infection disrupts the well-organized mitochondrial network found in uninfected HeLa cells. C. trachomatis infected HeLa cells showed re-localization of cellular mitochondria toward the bacterial inclusion. The mitochondria were observed to begin re-localization at 10 hpi with gradual increase in per cent re-localization with subsequent time points. Highest per cent mitochondrial re-localization was observed at 36 hpi (81.1%), displaying all most all mitochondria accumulated around Chlamydial inclusion. The results clearly indicated the close association between host mitochondria and Chlamydial inclusion. Moreover, re-localization of mitochondria in close proximity of inclusion also indicated potential acquisition of essential metabolites and energy in form of ATP by bacterial inclusion from host mitochondria.
M.S. in Biology, May 2017
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MITOCHONDRIA RELOCALIZATION IN CHLAMYDIA TRACHOMATIS INFECTED HFF-1 CELLS
Title
MITOCHONDRIA RELOCALIZATION IN CHLAMYDIA TRACHOMATIS INFECTED HFF-1 CELLS
Creator
Shuppara, Alexander Mitchell
Date
2021
Description
Chlamydia trachomatis is an infectious, gram-negative, obligate intracellular human bacterial pathogen. With over eight hundred million cases...
Show moreChlamydia trachomatis is an infectious, gram-negative, obligate intracellular human bacterial pathogen. With over eight hundred million cases worldwide, C. trachomatis is the most prevalent sexually transmitted infection. It manifests as either trachoma, lymphogranuloma venereum, or other urogenital tract sequelae. As an intracellular pathogen, Chlamydia must scavenge for essential metabolites from establishing networks with its host’s organelles including Golgi apparatus, endoplasmic reticulum, endocytic vesicles, mitochondria, and the cytoskeleton. C. trachomatis was considered an “energy parasite” that is entirely dependent on their host’s ATP production. Yet, recent mitochondrial inhibitor-based evidence suggests that C. trachomatis possess a sodium-based energy gradient for ATP production. Despite this finding, literature on specific interactions between host cell mitochondria and C. trachomatis requires further definition. This project evaluates mitochondrial dynamics changes from C. trachomatis infection in the human foreskin fibroblast cell line, HFF-1. We first defined C. trachomatis growth characteristics in HFF-1 over 36 hours-post infection. Next, we determined changes in mitochondrial dynamics and content throughout infection using immunofluorescent and immunoblotting techniques. observations on infected cells show mitochondrial morphology changes from an elongated appearance at the early stages of infection to fragmented in the late infection stages. Unlike in HeLa cells, HFF-1 remains in a normal distribution throughout the cell and we do not observe mitochondria relocalizing toward the inclusion. By studying mitochondrial relocalization dynamics, new insights into the dynamic and parasitic relationship of Chlamydia and its host can be discovered.
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SODIUM-BASED ENERGY METABOLISM AND DYNAMIC ENERGY DEPENDENCY OF CHLAMYDIA TRACHOMATIS
Title
SODIUM-BASED ENERGY METABOLISM AND DYNAMIC ENERGY DEPENDENCY OF CHLAMYDIA TRACHOMATIS
Creator
Liang, Pingdong
Date
2019
Description
Chlamydia trachomatis is an obligate intracellular bacterium that is responsible for various human diseases including trachoma, genital tract...
Show moreChlamydia trachomatis is an obligate intracellular bacterium that is responsible for various human diseases including trachoma, genital tract infections, and lymphogranuloma venereum. Energy metabolism consists many essential pathways to generate energy for every organism. However, it remains much unknown in C. trachomatis. For decades, C. trachomatis has been considered as an “energy parasite”, which needs the energy supply from the host cells entirely. In contrast, genomic studies show that this bacterium is capable of encoding enzymes that involve energy metabolism. However, no experimental data were provided to support the genomic information due to the peculiar developmental cycle of C. trachomatis inside the host cells. In this project, the oxidative phosphorylation pathway of C. trachomatis is first identified with experimental results. This pathway starts with the sodium pumping NADH:Ubiquinone oxidoreductase enzyme complex (NQR) transferring the electrons along the respiratory chain and generating a sodium gradient across the membrane. C. trachomatis contains an A-type ATPase that can utilize this sodium gradient to generate ATP. In vitro experiments in mammalian cells with different respiratory inhibitors show that C. trachomatis is not an obligate energy parasite. Instead, it has a dynamic energy dependency on the host metabolism that the bacterium switches from entirely to partially relying on the host energy metabolism for its energy requirement. The sodium gradient established by NQR and/or other transporters is of great importance to chlamydial metabolism. Further, the respiratory inhibitors test on interferon-γ-induced persistence of C. trachomatis in mammalian cell cultures shows that an inhibited energy metabolism prevents and eliminates the persistent form. This study provides new insights about antibiotics development and therapeutic methods against C. trachomatis infections.
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