Induction of Necrosis in Human Macrophage Cell Lines by Corynebacterium diphtheriae and Corynebacterium ulcerans Strains Isolated from Fatal Cases of Systemic Infections

Abstract

When infecting a human host, Corynebacterium diphtheriae and Corynebacterium ulcerans are able to impair macrophage maturation and induce cell death. However, the underlying molecular mechanisms are not well understood. As a framework for this project, a combination of fluorescence microscopy, cytotoxicity assays, live cell imaging, and fluorescence-activated cell sorting was applied to understand the pathogenicity of two Corynebacterium strains isolated from fatal cases of systemic infections. The results showed a clear cytotoxic effect of the bacteria. The observed survival of the pathogens in macrophages and, subsequent, necrotic lysis of cells may be mechanisms explaining dissemination of C. diphtheriae and C. ulcerans to distant organs in the body.

Live cell imaging of macrophage/bacterium interaction demonstrates cell lysis induced by Corynebacterium diphtheriae and Corynebacterium ulcerans

“…The data sets presented here support and extend results on the interaction of Corynebacterium species; i.e. C. diphtheriae , C. glutamicum and C. ulcerans , with different phagocytic cells published previously [8–12]. Limitations of the data sets are (i) the use of only one strain per species applied, (ii) the analysis of only one human macrophage-like cell line and (iii) the use of only one MOI in the infection experiments.…”

“…Recent publications showed that C. diphtheriae as well as C. ulcerans may interfere with phagolysosome maturation in murine and human macrophages after phagocytosis [8–11]. Most recently, a study combining of fluorescence microscopy, cytotoxicity assays and fluorescence-activated cell sorting revealed that these pathogenic corynebacteria induce necroptosis in human phagocytic cell lines [12]. It was suggested that survival in macrophages and subsequent necrotic lysis of cells may be mechanisms for dissemination of C. diphtheriae and C. ulcerans within the host and support colonization of host tissues far distant from the infection site.…”

“…Staining was carried out using 0.1 µg ml −1 Hoechst 33342 (Thermo Fisher Scientific, Waltham, MA, USA) and 1 µg ml −1 propidium iodide (Invitrogen, Carlsbad, CA, USA) in PBS. For infection, overnight cultures of green fluorescent protein (GFP)-expressing corynebacteria [12] grown in kanamycin-containing Heart infusion (HI) medium (Becton–Dickinson, Sparks, MD, USA) were inoculated to an OD 600 of 0.1 in fresh medium, harvested at the beginning of the exponential growth phase (OD 600 approx. 0.4 to 0.6) and used to infect macrophages at an MOI of 25.…”

Interactions between the Re-Emerging Pathogen Corynebacterium diphtheriae and Host Cells

“…HC04 was isolated from a catheter of a 7-year-old girl that developed complications including arthritis, myositis, and peripheral and central nervous system emboli, as well as a microaneurysm with brain hemorrhage, and died due to septic shock caused by endocarditis [ 80 , 81 ]. Infection of THP-1 cells with C. diphtheriae HC04 resulted in condensation of DNA in macrophage nuclei and induced cell lysis, which are clear signs of necrosis [ 82 ]. Live cell imaging experiments revealed that these detrimental effects on macrophages are due to bacterial endocytosis and replication within the host cells.…”

Host–Pathogen Interaction 3.0

“…Reviews submitted summarize our current knowledge on important pathogens such as Corynebacterium diphtheriae [ 7 ], Staphylococcus aureus [ 8 , 9 ], Legionella species [ 10 ] and Neisseria meningitidis [ 11 ], while research articles highlight specific aspects of host–pathogen interaction. Different mycobacterial pathogens [ 12 , 13 ], Corynebacterium species [ 14 , 15 ], Helicobacter pylori [ 16 ], Mycoplasma fermentans [ 17 ], rickettsiae [ 18 ] and S. enterica [ 19 ] were studied in respect to their interaction with human cell lines. In addition to other human pathogens [ 20 , 21 , 22 , 23 , 24 ], animal- [ 25 , 26 ] and plant-pathogenic bacteria [ 27 , 28 , 29 , 30 ] were investigated.…”