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Published on: July 12, 2018
Pseudomonas aeruginosa PAO1 induces distinct cell death mechanisms in H9C2 cells and its differentiated form
Jothi Ranjani1, Muthuirulan Pushpanathan1, Ayyavu Mahesh2
1Department of Genetics, Centre for Excellence in Genomic Sciences, School of Biological Sciences, Madurai Kamaraj University, Madurai, Tamil Nadu, India.
Abstract:
Bacterial infections in myocardium may lead to the myocardial damage, which may progress to dilated cardiomyopathy and cardiac arrest. Pseudomonas aeruginosa has been reported to cause myocarditis and other systemic infections especially in immunocompromised patients. To understand the cellular responses during the establishment of infection in myocardium, we challenged differentiated H9C2 cells with P. aeruginosa PAO1. We also did comparison studies with infected undifferentiated form of H9C2 cells. Invasion studies revealed that PAO1 can invade both forms of cells and is able to survive and replicate within the host. Internalization of PAO1 was confirmed by live cell imaging and flow cytometry analysis. Though invasion of the pathogen triggered an increased ROS production in the host cells at earlier post-infection periods, it was decreased at later post-infection periods. Invasion of PAO1 induced cell death through apoptosis in differentiated H9C2 cells. Significant decrease in cell size, formation of polarized mitochondria, and nuclear fragmentation were observed in the infected differentiated cells. On the contrary, cell death preceded by multinucleation was observed in infected undifferentiated H9C2 cells. Morphological markers such as multinuclei and micro nuclei were observed. Cell cycle arrest in G2/M phase corroborates that the undifferentiated H9C2 cells experienced cell death preceded by multinucleation.
Insights
Pseudomonas aeruginosa infection damages heart cells, leading to apoptosis in differentiated cells and multinucleation in undifferentiated cells. This study investigates bacterial invasion and host cell responses in myocardial infection models.
Area of Science:
- Cardiovascular Biology
- Infectious Diseases
- Cellular Microbiology
Background:
- Bacterial myocarditis can cause severe heart damage, potentially leading to dilated cardiomyopathy and cardiac arrest.
- Pseudomonas aeruginosa is a significant pathogen, particularly in immunocompromised individuals, causing systemic infections and myocarditis.
Purpose of the Study:
- To investigate the cellular responses of H9C2 cells to Pseudomonas aeruginosa PAO1 infection.
- To compare the effects of P. aeruginosa infection on differentiated versus undifferentiated H9C2 cells.
Main Methods:
- Invasion assays using P. aeruginosa PAO1 and H9C2 cell lines (differentiated and undifferentiated).
- Live cell imaging and flow cytometry to confirm bacterial internalization.
- Analysis of reactive oxygen species (ROS) production, cell morphology, and cell cycle progression.
Main Results:
- P. aeruginosa successfully invaded and replicated within both differentiated and undifferentiated H9C2 cells.
- ROS production was initially increased then decreased in infected cells.
- Differentiated cells underwent apoptosis with decreased cell size and mitochondrial polarization, while undifferentiated cells showed multinucleation and G2/M cell cycle arrest before death.
Conclusions:
- P. aeruginosa infection induces distinct cellular death pathways in differentiated and undifferentiated H9C2 cells.
- The study provides insights into host-pathogen interactions within a myocardial infection context.
- Understanding these differential responses is crucial for developing targeted therapies against bacterial myocarditis.
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