Mechanism Of Radiation-induced Ferroptosis In Caenorhabditis Elegans

Ferroptosis is iron-dependent,different from apoptosis,necrosis,autophagy and other new programmed death modes.Its regulatory mechanism mainly involves iron transport,amino acid metabolism and lipid peroxidation.As a mode of cell death,ferroptosis plays a key role in the treatment of many diseases,such as radiation/chemotherapy for tumors.It has been shown that radiation can induce ferroptosis at the cellular level by inducing ROS increase or abnormal expression of certain genes,leading to lipid peroxidation and GPX4 decrease.But it is not clear whether radiation can induce ferroptosis at the individual level.Based on this,we used C.elegans as a living animal model to investigate the molecular mechanism of radiation-mediated ferroptosis at the living level.First,we found that radiation can disrupt the activity of glutathione peroxidase（Gpx）,cut the expression of gpx1（GPX4）,a marker of ferroptosis inhibit the production of reduced glutathione（GSH）,and increase the concentration of Fe²⁺and the level of lipid peroxidation products（MDA）.These ferroptosis markers demonstrate that radiation can induce ferroptosis in C.elegans.By means of quantitative fluorescence PCR,we found that the expression level of cep-1（P53）was increased while that of aat-9（SLC7A11）was significantly decreased after radiation treatment.Compared with wild-type n2,it was found that irradiation induced MDA level decreased,GSH content increased,gpx1 and aat-9 gene expression levels increased in cep-1 defective strains.These results indicate that radiation-induced ferroptosis reduces GSH content and gpx1 expression through the cep-1-aat-9 signal axis.Secondly,the expression level and apoptosis rate of core apoptosis genes were further detected after radiation treatment,and it was found that the level of egl-1 was increased,the level of ced-9 was decreased,and the level of apoptosis was increased.Compared with wild-type strain n2,loss of egl-1 reduced irradiation-induced ferroptosis,while loss of ced-9 promoted irradiation-induced ferroptosis,suggesting that core apoptosis genes mediate irradiation-induced ferroptosis.At the same time,we also found that acs-17（ACSL4）mediated lipid metabolism pathway is also involved in radiation-induced ferroptosis signaling.Fluorescence strain CF1553（SOD3:GFP）was used to detect the levels of reactive oxygen radicals（ROS）and m RNA levels of related genes in C.elegans.ROS levels were significantly increased after irradiation,indicating that irradiation induced ferroptosis in C.elegans through oxidative stress.In addition,n-acetyl-L-cysteine（NAC）,a ROS scavher,inhibits radiation-induced increases in cep-1 and egl-1 and promotes the expression of iron-death genes aat-9 and gpx1.These results suggest that radiation induces ferroptosis in nematodes through ROS regulation of the core apoptosis pathway and the cep-1-aat-9 signaling axis.Finally,we investigated the effect of radiation on nematodes vulva tumor.The radiation sensitivity of nematodes was verified by let-60,a nematode strain with overactivation of RAS oncogene,and radiation increased the rate of vulva distortion.By using the H₂DCF-DA probe,it was found that NAC could antagonize the vulva distortion caused by the increase of ROS level,which indicated that oxidative stress mediated radiation induced vulva distortion.In conclusion,our study showed that radiation can induce oxidative stress response at the in vivo level,and ROS produced by oxidative stress can induce ferroptosis signal and regulate radiation sensitivity by activating apoptosis pathway and cep-1-aat-9 signaling pathway.This study provides a strong experimental basis for improving the effect of tumor radiotherapy at the individual level,and is of great significance for the study of ferroptosis in C.elegans.