Fluorescence Lifetime Imaging Unravels C. trachomatis Metabolism and Its Crosstalk with the Host Cell

PLoS Pathogens

Philipp Steven¹  Regina Orzekowsky-Schröder²  Gereon Hüttmann²  Inke R. König³  Werner Solbach⁴  Márta Szaszák⁴  Kensuke Shima⁴  Jan Rupp⁴ 

[1] Department of Ophthalmology, UK-SH, Campus Lübeck, Lübeck, Germany;Institute of Biomedical Optics, University of Lübeck, Lübeck, Germany;Institute of Medical Biometry and Statistics, University of Lübeck, Lübeck, Germany;Institute of Medical Microbiology and Hygiene, University of Lübeck, Lübeck, Germany

关键词: Chlamydia infection;    Chlamydia trachomatis;    Chlamydia;    Cell metabolism;    Host cells;    Fluorescence imaging;    Fluorescence;    Glucose metabolism;   

DOI  :  10.1371/journal.ppat.1002108

学科分类：生物科学（综合）

来源: Public Library of Science

【 摘 要 】

Chlamydia trachomatis is an obligate intracellular bacterium that alternates between two metabolically different developmental forms. We performed fluorescence lifetime imaging (FLIM) of the metabolic coenzymes, reduced nicotinamide adenine dinucleotides [NAD(P)H], by two-photon microscopy for separate analysis of host and pathogen metabolism during intracellular chlamydial infections. NAD(P)H autofluorescence was detected inside the chlamydial inclusion and showed enhanced signal intensity on the inclusion membrane as demonstrated by the co-localization with the 14-3-3β host cell protein. An increase of the fluorescence lifetime of protein-bound NAD(P)H [τ2-NAD(P)H] inside the chlamydial inclusion strongly correlated with enhanced metabolic activity of chlamydial reticulate bodies during the mid-phase of infection. Inhibition of host cell metabolism that resulted in aberrant intracellular chlamydial inclusion morphology completely abrogated the τ2-NAD(P)H increase inside the chlamydial inclusion. τ2-NAD(P)H also decreased inside chlamydial inclusions when the cells were treated with IFNγ reflecting the reduced metabolism of persistent chlamydiae. Furthermore, a significant increase in τ2-NAD(P)H and a decrease in the relative amount of free NAD(P)H inside the host cell nucleus indicated cellular starvation during intracellular chlamydial infection. Using FLIM analysis by two-photon microscopy we could visualize for the first time metabolic pathogen-host interactions during intracellular Chlamydia trachomatis infections with high spatial and temporal resolution in living cells. Our findings suggest that intracellular chlamydial metabolism is directly linked to cellular NAD(P)H signaling pathways that are involved in host cell survival and longevity.

【 授权许可】

CC BY