ATP Released from Low-dose Gamma Ray-irradiated Cells Activates Intracellular Antioxidant Systems via Purine Receptors

Abstract

Antioxidants are known to prevent oxidative damage in cells caused by radiation. We have previously reported that whole-body irradiation with low doses of gamma rays to mice elevates the antioxidant thioredoxin-1 (Trx-1) levels in several organs. Furthermore, gamma ray irradiation also causes ATP release from the exposed cells. Extracellular ATP release in response to various stimuli has been reported to regulate the expression of intracellular antioxidants through activation of purinergic P2 receptors.Here, we review the relation between gamma-radiation-induced ATP release and the induction of cellular Trx-1 via purinergic signaling. Irradiation with gamma rays or exogenously adding ATP cause an increase in Trx-1 expression, and these phenomena disappear in the presence of an ecto-nucleotidase. Further, it is revealed that ATP generates intracellular reactive oxygen species (ROS), and thereby increases Trx-1 expression as an adaptive response to ROS.These findings suggest that gamma-radiation-induced release of extracellular ATP may contribute to the production of ROS via purinergic signaling, thereby leading to the promotion of intracellular antioxidants in response to an oxidative stress.

Effect of Gamma Radiation on Growth and Metabolic Activities of Arthrospira platensis

“…They reported 18 new expressed proteins that were suggested to be involved in photosynthesis, carbohydrate biosynthesis and energy metabolism. Kojima et al (2011) studied the role of antioxidants to prevent the oxidative damage of gamma radiation and ATP released by low dose of gamma irradiated cells and the relation between gamma-radiation-induced ATP release and induction of cellular antioxidant thioredoxin-1 (Trx-1) via purinergic signaling. Irradiation with gamma rays, or exogenously adding ATP caused an increase in Trx-1 expression.…”

Embryos of the zebrafish Danio rerio in studies of non-targeted effects of ionizing radiation

“…Reactive oxygen species (ROS), which were generated from irradiated cells, were among the reported bystander signals, which could lead to oxidative stress and DNA damage in nearby unirradiated cells. In contrast, the ROS production in irradiated cells upon radiation exposure could also activate the synthesis of antioxidants [7], and an increase in the antioxidant level could stimulate a defense mechanism, and it is established that the defense mechanism plays a role in the radioadaptive response (RAR) [8]. The RAR could protect cells from a subsequent challenging radiation.…”

Gonadal transcriptome analysis of wild contaminated female European eels during artificial gonad maturation

“…Among ENTPDase, the gene entpd8 was up-regulated in eels from Gironde. The entpd8 gene encodes for a transmembrane protein that hydrolyzes ATP into ADP (Kojima et al, 2011). Both ATP and ADP could activate purinergic membrane receptors coupled to G proteins.…”