### Radiation-induced protein redistribution and modification involved in DNA damage response and intercellular communication

Birger Dieriks UGent (2009)
abstract
Human cells are exposed to a wide range of stressors that influence their responses on different levels. There are strong indications that cells endure these stressors as an entity. Increasing evidence suggests that individual cells are not closed systems isolated from their environment but continuously exchange information with each other. Two non-targeted effects were studied: (1) Bystander effects occur when non-treated cells – that are in contact with exposed cells either through the medium or gap junctions – reveal effects similar to those seen in exposed cells. (2) In adaptive response, cells – either directly or indirectly exposed – are influenced by a prior treatment. Both phenomena were studied using high throughput cytometry and multiplex array screening. Central in this investigation was H2AX, a protein belonging to the histon complex that plays an important role in DNA damage response. In response to double stranded breaks (DSB) H2AX is phosphorylated (γH2AX) and is considered as signal enhancer for the DSB repair pathway. The DNA damage response of human fibroblast was analyzed and H2AX analysis revealed the presence of a bystander effect and an adaptive response. In addition, we analyzed the cytokines that were present in the culture medium after exposure to ionizing radiation. We could also link the upregulation of γH2AX in bystander cells to the presence of these secreted cytokines in the culture medium. In line with the above-mentioned results we analyzed the DNA damage response in fibroblasts exposed to cosmic radiation during the Foton M3 space mission. This fully automated mission lasted for 12 days and completed 190 orbits around the earth. During the space experiment, we tested and validated a compact, biological dosimeter, which can be used in future space flights. Finally, we focused on a specific signaling molecule, cyclophilin B (CypB). CypB is secreted into the culture medium, but has the necessary signal peptides for an efficient retrograde transport to the nucleus. In order to identify the various peptide sequences necessary for these relocalizations, different GFP constructs were made. We identified a nucleolar localization sequence that allowed transport of CypB and could link CypB to a role in rDNA transcription.
author
promoter
UGent
organization
alternative title
Stralingsgeïnduceerde proteïne herverdeling en modificatie betrokken in DNA schade respons en intercellulaire communicatie
year
type
dissertation (monograph)
subject
keyword
γH2AX, non-targeted effects, cytokines, Cyclophilin B
pages
197 pages
publisher
Ghent University. Faculty of Bioscience Engineering
place of publication
Ghent, Belgium
defense location
Gent : Faculteit Bio-ingenieurswetenschappen
defense date
2009-12-09 16:00
ISBN
978-90-5989-338-2
language
English
UGent publication?
yes
classification
D1
id
812827
handle
http://hdl.handle.net/1854/LU-812827
alternative location
http://lib.ugent.be/fulltxt/RUG01/001/368/209/RUG01-001368209_2010_0001_AC.pdf
date created
2009-12-16 13:44:12
date last changed
2010-01-26 10:41:21
@phdthesis{812827,
abstract     = {Human cells are exposed to a wide range of stressors that influence their responses on different levels. There are strong indications that cells endure these stressors as an entity. Increasing evidence suggests that individual cells are not closed systems isolated from their environment but continuously exchange information with each other. Two non-targeted effects were studied: (1) Bystander effects occur when non-treated cells -- that are in contact with exposed cells either through the medium or gap junctions -- reveal effects similar to those seen in exposed cells. (2) In adaptive response, cells -- either directly or indirectly exposed -- are influenced by a prior treatment.
Both phenomena were studied using high throughput cytometry and multiplex array screening. Central in this investigation was H2AX, a protein belonging to the histon complex that plays an important role in DNA damage response. In response to double stranded breaks (DSB) H2AX is phosphorylated (\ensuremath{\gamma}H2AX) and is considered as signal enhancer for the DSB repair pathway. The DNA damage response of human fibroblast was analyzed and H2AX analysis revealed the presence of a bystander effect and an adaptive response. In addition, we analyzed the cytokines that were present in the culture medium after exposure to ionizing radiation. We could also link the upregulation of \ensuremath{\gamma}H2AX in bystander cells to the presence of these secreted cytokines in the culture medium. In line with the above-mentioned results we analyzed the DNA damage response in fibroblasts exposed to cosmic radiation during the Foton M3 space mission. This fully automated mission lasted for 12 days and completed 190 orbits around the earth. During the space experiment, we tested and validated a compact, biological dosimeter, which can be used in future space flights. Finally, we focused on a specific signaling molecule, cyclophilin B (CypB). CypB is secreted into the culture medium, but has the necessary signal peptides for an efficient retrograde transport to the nucleus. In order to identify the various peptide sequences necessary for these relocalizations, different GFP constructs were made. We identified a nucleolar localization sequence that allowed transport of CypB and could link CypB to a role in rDNA transcription.},
author       = {Dieriks, Birger},
isbn         = {978-90-5989-338-2},
keyword      = {\ensuremath{\gamma}H2AX,non-targeted effects,cytokines,Cyclophilin B},
language     = {eng},
pages        = {197},
publisher    = {Ghent University. Faculty of Bioscience Engineering},
school       = {Ghent University},
title        = {Radiation-induced protein redistribution and modification involved in DNA damage response and intercellular communication},
url          = {http://lib.ugent.be/fulltxt/RUG01/001/368/209/RUG01-001368209\_2010\_0001\_AC.pdf},
year         = {2009},
}


Chicago
Dieriks, Birger. 2009. “Radiation-induced Protein Redistribution and Modification Involved in DNA Damage Response and Intercellular Communication”. Ghent, Belgium: Ghent University. Faculty of Bioscience Engineering.
APA
Dieriks, B. (2009). Radiation-induced protein redistribution and modification involved in DNA damage response and intercellular communication. Ghent University. Faculty of Bioscience Engineering, Ghent, Belgium.
Vancouver
1.
Dieriks B. Radiation-induced protein redistribution and modification involved in DNA damage response and intercellular communication. [Ghent, Belgium]: Ghent University. Faculty of Bioscience Engineering; 2009.
MLA
Dieriks, Birger. “Radiation-induced Protein Redistribution and Modification Involved in DNA Damage Response and Intercellular Communication.” 2009 : n. pag. Print.