Recent studies showed that hydrogen can be used as an effective radioprotective agent through scavenging free radicals. This study was undertaken to evaluate the radioprotective effects of hydrogen on immune system in mice. H₂ was dissolved in physiological saline using an apparatus produced by our department. Spleen index and histological analysis were used to evaluate the splenic structural damage. Spleen superoxide dismutase, GSH, MDA were measured to appraise the antioxidant capacity and a DCF assay for the measurement of radical oxygen species. Cell apoptosis was evaluated by an Annexin V‐FITC and propidium iodide staining method as well as the apoptotic proteins such as Bcl‐2, Bax, caspase‐3 and c‐caspase‐3. CD4+ and CD8+ T cells subtypes were detected by flow cytometry with FITC‐labelled antimouse CD4 and PE antimouse CD8 staining. Real‐time PCR was utilized to determine the CD4+ T cell subtypes and related cytokines. Our study demonstrated that pre‐treatment with H₂ could increase the spleen index and attenuate the radiation damage on splenic structure. Radical oxygen species level was also reduced by H₂ treatment. H₂ also inhibited radiation‐induced apoptosis in splenocytes and down‐regulated pro‐apoptotic proteins in living mice. Radiation‐induced imbalance of T cells was attenuated by H₂ . Finally, we found that H₂ could regulate the polarization of CD4+ T cells and the level of related cytokines. This study suggests H₂ as an effective radioprotective agent on immune system by scavenging reactive oxygen species.

As a common serious complication of thoracic radiotherapy, radiation-induced pulmonary fibrosis (RIPF) severely limits radiation therapy approaches. Epithelial–mesenchymal transition (EMT) is a direct contributor to the fibroblast pool during fibrogenesis, and prevention of EMT is considered an effective strategy to inhibit tissue fibrosis. Our previous study revealed that TANK-binding kinase 1 (TBK1) regulates EMT in lung cancer cells. In the present study, we aimed to investigate the therapeutic potential of targeting TBK1 to prevent RIPF and EMT progression. We found radiation-induced EMT and pulmonary fibrosis in normal alveolar epithelial cells and lung tissues. TBK1 knockdown or inhibition significantly reversed EMT in vivo and in vitro and attenuated pulmonary fibrosis and collagen deposition. Moreover, we observed that TBK1 was elevated in a time- and dose-dependent manner by radiation. Meanwhile, radiation also induced time- and dose-dependent activation of AKT and ERK, each of whose inhibitors suppressed radiation-induced EMT. Intriguingly, silencing of TBK1 with shRNA also blocked the radiation-induced activation of AKT and ERK signaling. The ERK inhibitor did not obviously affect the expression of TBK1 or phosphorylated AKT, while AKT inhibition suppressed activation of ERK without changing the expression of TBK1. Finally, we found that a TBK1 inhibitor inhibited inflammatory cytokine expression in a RIPF model and Amlexanox protected normal cells and mice from ionizing radiation. In conclusion, our results indicate that the TBK1–AKT–ERK signaling pathway regulates radiation-induced EMT in normal alveolar epithelial cells, suggesting that TBK1 is a potential target for pulmonary fibrosis prevention during cancer radiotherapy.

Radiation protection on male testis is an important task for ionizing radiation‐related workers or people who receive radiotherapy for tumours near the testicle. In recent years, Toll‐like receptors (TLRs), especially TLR4, have been widely studied as a radiation protection target. In this study, we detected that a low‐toxicity TLR4 agonist monophosphoryl lipid A (MPLA) produced obvious radiation protection effects on mice testis. We found that MPLA effectively alleviated testis structure damage and cell apoptosis induced by ionizing radiation (IR). However, as the expression abundance differs a lot in distinct cells and tissues, MPLA seemed not to directly activate TLR4 singling pathway in mice testis. Here, we demonstrated a brand new mechanism for MPLA producing radiation protection effects on testis. We observed a significant activation of TLR4 pathway in macrophages after MPLA stimulation and identified significant changes in macrophage‐derived exosomes protein expression. We proved that after MPLA treatment, macrophage‐derived exosomes played an important role in testis radiation protection, and specially, G‐CSF and MIP‐2 in exosomes are the core molecules in this protection effect.

Glibenclamide, a diabetic drug, prevents acute radiation-induced liver injury of mice via up-regulating intracellular ROS and subsequently activating Akt–NF-κB pathway Glibenclamide, a diabetic drug, prevents acute radiation-induced liver injury of mice via up-regulating intracellular ROS and subsequently activating Akt—NF-κB pathway

Background: To block repairs of DNA damages, especially the DNA double strand break (DSB) repair, can be used to induce cancer cell death. DSB repair depends on a sequential activation of DNA repair factors that may be potentially targeted for clinical cancer therapy. Up to now, many protein components of DSB repair complex remain unclear or poorly characterized. In this study, we discovered that Transglutaminase 2 (TG2) acted as a new component of DSB repair complex. Methods: A bioinformatic analysis was performed to identify DNA damage relative genes from dataset from The Cancer Genome Atlas. Immunofluorescence and confocal microscopy were used to monitor the protein localization and recruitment kinetics. Furthermore, immunoprecipitation and mass spectrometry analysis were performed to determine protein interaction of both full-length and fragments or mutants in distinct domain. In situ lung cancer model was used to study the effects cancer therapy in vivo. Results: After DSB induction, cytoplasmic TG2 was extensively mobilized and translocated into nucleus after phosphorylated at T162 site by DNA-PKcs. Nuclear TG2 quickly accumulated at DSB sites and directly interacting with Topoisomerase IIα (TOPOIIα) with its TGase domain to promote DSB repair. TG2 deficient cells lost capacity of DSB repair and become susceptible to ionizing radiation. Specific inhibition of TG2-TOPOIIα interaction by glucosamine also significantly inhibited DSB repair, which increased sensitivity in lung cancer cells and engrafted lung cancers. Conclusions: These findings elucidate new mechanism of TG2 in DSB repair trough directly interacting with TOPOIIα, inhibition of which provided potential target for overcoming cancer resistance.