Crosstalk between Fas and JNK determines lymphocyte apoptosis after ionizing radiation

The Protective Effects and Mechanism of Doxepin on Radiation–Induced Lung Injury in Rats

Radiation-induced lung injuries (RILI) is one of the serious complications of radiotherapy posed by the damage of alveolar cells and inflammation over-reaction. We aimed to investigate the potential protective effects of doxepin on RILI (20 Gy total dose at 3 Gy/min of X-ray irradiation), as well as its underlying mechanism. For animal experiments, such parameters as Immunohistochemistry and hematoxylin and eosin (H&E) staining, WBC (white blood cell), CRP (C-reactive protein), Western blot, and q-PCR were detected. The results indicated that both survival status and weight increase of irradiated rats treated by doxepin (3 mg/kg/day, rat) were higher than those of treated with irradiation alone (Dosing started the day before irradiation). Further, histological examinations showed doxepin could tenuate the radiation injury, as indicated as alveolar inflammatory exudation and there was only mild interstitial inflammation infiltration. Western blotting and q-PCR showed that expression of NF-κβ in X group were higher than that in XMD group. For the first time, we reported doxepin functioned as a radioprotectant candidate, which provide a promising application of doxepin for protecting radiotherapy injuries.

Biological rhythms in the deep-sea hydrothermal mussel Bathymodiolus azoricus

Biological rhythms are a fundamental property of life. The deep ocean covers 66% of our planet surface and is one of the largest biomes. The deep sea has long been considered as an arrhythmic environment because sunlight is totally absent below 1,000 m depth. In the present study, we have sequenced the temporal transcriptomes of a deep-sea species, the ecosystem-structuring vent mussel Bathymodiolus azoricus. We reveal that tidal cycles predominate in the transcriptome and physiology of mussels fixed directly at hydrothermal vents at 1,688 m depth at the Mid-Atlantic Ridge, whereas daily cycles prevail in mussels sampled after laboratory acclimation. We identify B. azoricus canonical circadian clock genes, and show that oscillations observed in deep-sea mussels could be either a direct response to environmental stimulus, or be driven endogenously by one or more biological clocks. This work generates in situ insights into temporal organisation in a deep-sea organism.

Little is known about gene expression of organisms in the deep sea, partially owing to constraints on sampling these organisms in situ. Here the authors circumvent this problem, fixing tissue of a deep-sea mussel at 1,688 m in depth, and later analyzing transcriptomes to reveal gene expression patterns showing tidal oscillations.

Local Irradiation Sensitized Tumors to Adoptive T Cell Therapy via Enhancing the Cross-Priming, Homing, and Cytotoxicity of Antigen-Specific CD8 T Cells

The successful generation of T cell-mediated immunity for the treatment of cancer has been a major focal point of research. One of the critical strategies of cancer immunotherapy is to efficiently activate antigen-specific CD8 T cells in the immunosuppressive tumor environment. Here, we used transgenic OT-I/CD45.2/Rag^−/− mice as a source of effector CD8 T cells to determine whether irradiation combined with adoptive T cell transfer therapy could improve T cell proliferation and effector function in murine tumor models. Local irradiation combined with adoptive T cell therapy showed a synergistic effect on tumor growth inhibition in mice. Mechanistically, irradiation increased the release of tumor-associated antigens, which facilitated cross-presentation of tumor-associated antigens by dendritic cells and the priming of antigen-specific T lymphocytes. Additionally, irradiation enhanced the homing of the antigen-specific T cells to tumor tissues via the increased release of CCL5, CXCL9, and CXCL11 from tumor cells. Moreover, irradiation enhanced the proliferation and effector function of both adoptively transferred T cells and endogenous antigen-specific T cells. Our findings provide evidence to support that local irradiation enhanced the therapeutic efficacy of adoptive T cell therapy for cancer, indicating that the combination of radiotherapy and adoptive T cell therapy may be a promising strategy for tumor treatment.

Increased circulating cell-free DNA levels and mtDNA fragments in interventional cardiologists occupationally exposed to low levels of ionizing radiation

Circulating cell-free DNA (ccf-DNA) and mtDNA (ccf-mtDNA) have often been used as indicators of cell death and tissue damage in acute and chronic disorders, but little is known about changes in ccf-DNA and ccf-mtDNA concentrations following radiation exposure. The aim of the study was to investigate the impact of chronic low-dose radiation exposure on serum ccf-DNA levels and ccf-mtDNA fragments (mtDNA-79 and mtDNA-230) of interventional cardiologists working in high-volume cardiac catheterization laboratory to assess their possible role as useful radiation biomarkers. We enrolled 50 interventional cardiologists (26 males; age = 48.4 ± 10 years) and 50 age- and gender-matched unexposed controls (27 males; age = 47.6 ± 8.3 years). Quant-iT™ dsDNA High-Sensitivity assay was used to measure circulating ccf-DNA isolated from serum samples. Quantitative analysis of mtDNA fragments was performed by real-time PCR. No significant relationships were found between ccf-DNA and ccf-mtDNA, and age, gender, smoking, or other clinical parameters. Ccf-DNA levels (44.2 ± 31.1 vs. 30.6 ± 19.2 ng/ml, P = 0.013), ccf-mtDNA-79 (2.6 ± 2.1 vs. 1.1 ± 0.8, P < 0.01), and ccf-mtDNA-230 copies (2.0 ± 1.8 vs. 1.04 ± 0.9, P = 0.02) were significantly higher in interventional cardiologists compared with the non-exposed group. In a subset (n = 15) of interventional cardiologists with a reliable reconstruction of cumulative professional exposure (59.7 ± 48.4 mSv; range: 1.4-182 mS), ccf-DNA (53.2 ± 41.3 vs. 36.4 ± 22.9 and 32.2 ± 20.5, P = 0.08), mtDNA-79 (2.4 ± 2.1 vs. 2.03 ± 1.7 and 1.09 ± 0.82, P = 0.05), and mtDNA-230 (2.0 ± 2.2 vs. 1.5 ± 1.4 and 1.04 ± 0.9, P = 0.09) tended to be significantly increased in high-exposure subjects compared with both low-exposure interventional cardiologists and controls. Our results provide evidence for a possible role of circulating DNA as a relevant biomarker of cellular damage induced by exposure to chronic low-dose radiation.

Simulated microgravity increases heavy ion radiation-induced apoptosis in human B lymphoblasts

AIMS

Microgravity and radiation, common in space, are the main factors influencing astronauts' health in space flight, but their combined effects on immune cells are extremely limited. Therefore, the effect of simulated microgravity on heavy ion radiation-induced apoptosis, and reactive oxygen species (ROS)-sensitive apoptosis signaling were investigated in human B lymphoblast HMy2.CIR cells.

MAIN METHODS

Simulated microgravity was achieved using a Rotating Wall Vessel Bioreactor at 37°C for 30 min. Heavy carbon-ion irradiation was carried out at 300 MeV/u, with a linear energy transfer (LET) value of 30 keV/μm and a dose rate of 1Gy/min. Cell survival was evaluated using the Trypan blue exclusion assay. Apoptosis was indicated by Annexin V/propidium iodide staining. ROS production was assessed by cytometry with a fluorescent probe dichlorofluorescein. Malondialdehyde was detected using a kit. Extracellular signal-regulated kinase (ERK), mitogen-activated protein kinase phosphatase-1 (MKP-1) and caspase-3 activation were measured by immunoblotting.

KEY FINDINGS

Simulated microgravity decreased heavy ion radiation-induced cell survival and increased apoptosis in HMy2.CIR cells. It also amplified heavy ion radiation-elicited intracellular ROS generation, which induced ROS-sensitive ERK/MKP-1/caspase-3 activation in HMy2.CIR cells. The above phenomena could be reversed by the antioxidants N-acetyl cysteine (NAC) and quercetin.

SIGNIFICANCE

These results illustrated that simulated microgravity increased heavy ion radiation-induced cell apoptosis, mediated by a ROS-sensitive signal pathway in human B lymphoblasts. Further, the antioxidants NAC and quercetin, especially NAC, might be good candidate drugs for protecting astronauts' and space travelers' health and safety.