Heavy ion radiation-induced DNA damage mediates apoptosis via the Rp127a-Rp15-MDM2-p53/E2F1 signaling pathway in mouse spermatogonia
ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY
Authors: Li, Hongyan; Zhang, Hong; Huang, Guomin; Dou, Zhihui; Xie, Yi; Si, Jing; Di, Cuixia
Abstract
The risk of exposure to ionizing radiation (IR) environments has increased with the development of nuclear technology. IR exposure induces excessive apoptosis of the spermatogonia, which leads to male infertility. Spermatogonia apoptosis may be involved in ribosomal stress triggered by DNA damage following exposure to IR because ribosomal proteins (RPs) directly interact with mouse double minute 2 homolog (MDM2) to induce apoptosis. This study aimed to use comparative proteomics and transcriptomics approach to screen the differential RPs and ribosomal mRNAs in mouse testes following high linear energy transfer (LET) carbon ion radiation (CIR). The expression of ribosomal large subunit protein 27a (Rp127a) decreased at both protein and mRNA levels in the spermatogonia in vivo. After 6 h of CIR, the immunofluorescence signal of 8-oxo-dG and phosphorylated ataxia-telangiectasia-mutated protein (ATM)/histone H2Ax increased, but that of Rp127a decreased in the spermatogonia of p53 wild-type and knockout mouse testes. Moreover, the nucleolin was scattered throughout the nucleoplasm after CIR. These results suggested that CIR-induced DNA damage might trigger ribosomal stress, and the reduction in the expression of Rp127a was associated with DNA damage in the spermatogonia. Similarly, in vitro, the immunofluorescence signal of 8-oxo-dG increased in the GC-1 cells after CIR. Moreover, the expression of Rp127a was regulated by DNA damage because the co-transfection of ATM and Rp127a or inhibition of ATM-treated CIR could restore the expression of Rp127a. Furthermore, the reduction in the expression of Rp127a led to weakened binding of E2F transcription factor 1 (E2F1) and p53 to MDM2, causing p53 activation and E2F1 degradation in p53 wild-type and knockdown GC-1 cells. This study proposed that heavy ion radiation-induced DNA damage mediated spermatogonia apoptosis via the Rp127a-Rp15-MDM2-p53/E2F1 signaling pathway. The results provided the underlying molecular mechanisms of spermatogonia apoptosis following exposure to high LET radiation.
Machine Learning and Multipath Fingerprints for Emitter Localization in Urban Scenario
DEVELOPMENTS AND ADVANCES IN DEFENSE AND SECURITY
Authors: de Sousa, Marcelo N.; Cardoso, Rafael L.; Melo, Henrique S.; Parente, Jose W. C., Jr.; Thoma, Reiner S.
Abstract
A hybrid approach is proposed to perform the locate and tracking a non-collaborative radio frequency emitter using ray tracing (RT) simulation tool, channel impulse response (CIR), and machine learning estimation. The technique can enhance communication intelligence (COMINT) systems or even perform the localization using a single sensor in an non-line-of-sight (NLOS) suburban scenario. A multipath fingerprint can identify the target position using the machine learning classification engine to perform the matching. Conventional localization techniques mitigate errors trying to avoid NLOS measurements in processing emitter position, while the multipath fingerprints proposed uses the reflection information to feed the pattern matching engine build on a machine learning classification framework. The methodwas applied to simulate a tactical scenario, where a navy frigate is in Ipanema and tries to track an RF emitter target in the Rio de Janeiro streets using only one RF sensors fixed in an aerostat in a hypothetical counterinsurgency situation.