Novel mechanism for the radiation-induced bystander effect: nitric oxide and ethylene determine the response in sponge cells.

6533b86efe1ef96bd12cc7d2

RESEARCH PRODUCT

Novel mechanism for the radiation-induced bystander effect: nitric oxide and ethylene determine the response in sponge cells.

Alexandra Borejko Isabel M. Müller Werner E. G. M�ller H. C. Schröder Renato Batel Hiroshi Ushijima Anatoli Krasko

subject

Ethylene DNA Complementary DNA damage Cell Survival Ultraviolet Rays Health Toxicology and Mutagenesis Molecular Sequence Data Gene Expression Apoptosis Biology Nitric Oxide Models Biological Nitric oxide Amidohydrolases chemistry.chemical_compound Gene expression Genetics Bystander effect Animals Amino Acid Sequence Cloning Molecular Molecular Biology Nitrites chemistry.chemical_classification Base Sequence Sequence Homology Amino Acid Ethylenes biology.organism_classification Cell biology Amino acid Porifera Suberites domuncula chemistry Biochemistry Apoptosis DNA Damage

description

Until now the bystander effect had only been described in vertebrates. In the present study the existence of this effect has been demonstrated for the phylogenetically oldest metazoan phylum, the Porifera. We used the demosponge Suberites domuncula for the experiments in the two-chamber-system. The lower dish contained irradiated "donor" cells (single cells) and the upper dish the primmorphs ("recipient" primmorphs). The "donor" cells were treated with UV-B light (40 mJ/cm2) and 100 microM hydrogen peroxide (H2O2), factors that exist also in the natural marine aquatic environment of sponges; these factors caused a high level of DNA strand breaks followed by a reduced viability of the cells. If these cells were added to the "recipient" primmorphs these 3D-cell cultures started to undergo apoptosis. This effect could be abolished by the NO-specific scavenger PTIO and ethylene. The conclusion that NO is synthesized by the UV-B/H2O2-treated cells was supported analytically. The cDNA encoding the enzyme dimethylarginine dimethylaminohydrolase (DDAH) was isolated from the "donor" cells. High levels of DDAH transcripts were measured in UV-B/H2O2-treated "donor" cells while after ethylene treatment the steady-state level of expression drops drastically. We conclude that in the absence of ethylene the concentration of the physiological inhibitor for the NO synthase ADMA is low, due to the high level of DDAH. In consequence, high amounts of NO are released from "donor" cells which cause apoptosis in "recipient" primmorphs. In contrast, ethylene reduces the DDAH expression with the consequence of higher levels of ADMA which prevent the formation of larger amounts of NO. This study describes the radiation-induced bystander effect also for the most basal metazoans and demonstrates that this effect is controlled by the two gases NO and ethylene.

year	journal	country	edition	language
2006-05-01	Mutation research

10.1016/j.mrfmmm.2005.09.007 https://pubmed.ncbi.nlm.nih.gov/16427660