Task Mechanisms for induction of bystander effects by high-energy particles in cells and tissues (Completed)
Last Published:  03/26/21 03:34:00 PM (Central)
Short Title: Bystander Effects
Responsible HRP Element: Space Radiation
Collaborating Org(s):
Funding Status: Completed - Task completed and produced a deliverable
Procurement Mechanism(s):

1. Test the hypothesis that bystander effects occur at particle fluences so low that only 1-2 % of cells in a culture dish are traversed by an energetic proton or HZE particle.

2. Extend our low fluence work to studies using repeated exposures of cells to low fluences and mixed (actually sequential) beams of more than one particle type. This will test the hypothesis that cells that have survived an initial traversal and sent a bystander signal, can again send a signal when traversed once again by a particle or can subsequently respond as bystanders to a hit in a neighboring cell.

3. Our studies have indicated that reactive oxygen species (ROS) are at least partially involved in transmittal of the Fe ion-induced bystander signal from hit to unirradiated cells. We will test the hypothesis that non-nuclear damage-initiated, metabolically produced ROS in hit cells are involved in the early steps of bystander signaling. Additionally, we will investigate chemical countermeasures to reduce the bystander responses based on removal of ROS or prevention of their formation.

4. In tissues, cells do not exist in isolation, and there is increasing interest in how signaling between cell types (especially stromal and epithelial) influences cellular responses to stresses. We will test the hypothesis that radiation-induced bystander signals can be sent between differing cell types, but the characteristics of the responses depend on the cell types and the types of radiation.

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