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Protein kinase C activation and vacuolation in HeLa cells invaded by Mycoplasma penetrans
Z Borovsky1, M Tarshis, P Zhang
1Department of Membrane and Ultrastructure Research, The Hebrew University-Hadassah Medical School, Jerusalem, Israel.
Abstract:
The AIDS-associated Mycoplasma penetrans is capable of inducing its own uptake by non-phagocytic cells. This study investigated the invasion of HeLa cells and its consequences by confocal laser scanning microscopy. Invasion was dependent on the duration of infection and temperature, diminished by inhibiting microfilament assembly with cytochalasin D and almost completely abolished by disorganising microtubules with vinblastine or taxol. After a short infection period (< 20 min), pronounced activation of protein kinase C was detected in host cells, whereas prolonged infection resulted in intensive vacuolation of the host cells and a pronounced increment in intracellular organic peroxide levels. A marked decrease in the extent of vacuolation was observed when peroxide accumulation was partially prevented by alpha-tocopherol. The possibility that M. penetrans entry into HeLa cells involves the activation of protein kinases and the recruitment of cytoskeleton components is discussed.
Insights
Mycoplasma penetrans, an AIDS-associated bacterium, invades non-phagocytic HeLa cells by hijacking host cell machinery. This invasion involves cytoskeletal rearrangement and leads to cellular damage, including vacuolation and increased peroxide levels.
Area of Science:
- Cell biology
- Microbiology
- Immunology
Background:
- Mycoplasma penetrans is an opportunistic pathogen associated with Acquired Immunodeficiency Syndrome (AIDS).
- Non-phagocytic cells, such as HeLa cells, are typically resistant to bacterial invasion.
- Understanding pathogen-host interactions is crucial for developing therapeutic strategies.
Purpose of the Study:
- To investigate the mechanism of Mycoplasma penetrans invasion into HeLa cells.
- To elucidate the cellular consequences of this invasion.
- To identify potential host factors involved in M. penetrans entry.
Main Methods:
- Confocal laser scanning microscopy was used to visualize and quantify bacterial invasion.
- Inhibition of cytoskeletal components (microfilaments and microtubules) using cytochalasin D, vinblastine, and taxol.
- Biochemical assays to detect protein kinase C activation and intracellular organic peroxide levels.
- Alpha-tocopherol was used to mitigate peroxide accumulation.
Main Results:
- M. penetrans invasion of HeLa cells is dependent on infection duration and temperature.
- Invasion requires intact microfilaments and microtubules, indicating cytoskeletal involvement.
- Short-term infection activates protein kinase C; prolonged infection causes vacuolation and increased intracellular peroxides.
- Preventing peroxide accumulation partially reduced vacuolation.
Conclusions:
- Mycoplasma penetrans actively invades non-phagocytic HeLa cells.
- Bacterial entry is mediated by host cell cytoskeleton dynamics and signaling pathways.
- Cellular damage, including vacuolation and oxidative stress, results from prolonged M. penetrans infection.