Programmed cell death (PCD) refers to cell suicide that results from a genetically encoded program. Although widespread among multicellular organisms, there are relatively few documented instances of PCD in bacteria. In bacteria, PCD appears to have roles in limiting the spread of bacteriophage, and in the formation of biofilms. We have uncovered a potential PCD pathway in the pathogenic bacterium Pseudomonas aeruginosa. This PCD pathway can be activated in a subset of cells in response to DNA damage and promotes the virulence of P. aeruginosa in a lung infection model. DNA damage results in cleavage of an essential transcription regulator that we call AlpR, which leads to the activation of a cell lysis program via the de-repression of the alpA gene. In turn, AlpA positively regulates expression of the alpBCDE lysis genes. The cell lysis that ensues could provide nutrients or liberate toxins or other bacterial factors that might facilitate lung colonization by he remaining P. aeruginosa cells in the population.
In Aim 1 we propose to determine how the AlpR-regulated alpBCDE genes influence cell lysis.
In Aim 2 we propose to determine how AlpA positively controls the expression of target genes and identify an additional component of the PCD pathway that may be under the control of AlpA. Finally, in Aim 3 we will begin to determine how the PCD of a subset of P. aeruginosa cells in a population enhances virulence in an acute pneumonia model. With these studies we hope to elucidate how a pathogen exploits PCD as a survival-promoting strategy during the course of an infection. Additionally, our findings may have implications for the treatment of P. aeruginosa infections with antibiotics that damage the DNA.

Public Health Relevance

The proposed work is expected to reveal how Pseudomonas aeruginosa, a notorious lung pathogen, regulates the expression of genes required for colonization of the host lung. They are also expected to reveal how cellular suicide of a subset of P. aeruginosa cells in a population is exploited to promote survival of the pathogen during the course of an infection. Additionally, our findings may have implications for the treatment of P. aeruginosa infections with antibiotics that damage the DNA.

Agency
National Institute of Health (NIH)
Institute
National Institute of Allergy and Infectious Diseases (NIAID)
Type
Research Project (R01)
Project #
5R01AI118955-02
Application #
9221981
Study Section
Special Emphasis Panel (ZRG1-IDM-V (02)M)
Program Officer
Lu, Kristina
Project Start
2016-02-15
Project End
2021-01-31
Budget Start
2017-02-01
Budget End
2018-01-31
Support Year
2
Fiscal Year
2017
Total Cost
$534,715
Indirect Cost
$165,512
Name
Boston Children's Hospital
Department
Type
Independent Hospitals
DUNS #
076593722
City
Boston
State
MA
Country
United States
Zip Code
02115