MiRNA expression profile of ionizing radiation-induced liver injury in mouse using deep sequencing

miR-146a-5p Alleviates Radiation-Induced Liver Fibrosis by Regulating PTPRA-SRC Signaling in Mice

Patients with hepatobiliary tumors who accept radiotherapy are at risk for radiation-induced liver fibrosis. MicroRNAs (miRNAs) have been implicated in the pathogenesis of radiation-induced liver damage and possess potential as novel biomarkers and therapeutic targets. However, the role of miR-146a-5p in radiation-induced liver fibrosis is less well understood. The current study was designed to evaluate the role of miR-146a-5p in radiation-induced liver fibrosis in mice and to investigate the possible mechanisms involved in miR-146a-5p-mediated effects. The experiments were performed on Institute of Cancer Research (ICR) mice which received fractionated radiation (30 Gy in 5 fractions) to the liver. The results show radiation could induce histopathological changes, liver dysfunction and fibrosis accompanied with decreased miR-146a-5p expression. miR-146a-5p agomir treatment resulted in recovery of liver function and reduced the amount of alpha-smooth muscle actin (α-SMA), collagen 1, protein tyrosine phosphatase receptor type A (PTPRA) and phosphorylated SRC in the livers of irradiated mice. Therefore, our study reveals that miR-146a-5p inhibits the progression of hepatic fibrosis after radiation treatment. And the beneficial role of miR-146a-5p may be relevant to PTPRA-SRC signaling pathway.

Radiation-induced liver disease: beyond DNA damage

Radiation-induced liver disease (RILD), also known as radiation hepatitis, is a serious side effect of radiotherapy (RT) for hepatocellular carcinoma. The therapeutic dose of RT can damage normal liver tissue, and the toxicity that accumulates around the irradiated liver tissue is related to numerous physiological and pathological processes. RILD may restrict treatment use or eventually deteriorate into liver fibrosis. However, the research on the mechanism of radiation-induced liver injury has seen little progress compared with that on radiation injury in other tissues, and no targeted clinical pharmacological treatment for RILD exists. The DNA damage response caused by ionizing radiation plays an important role in the pathogenesis and development of RILD. Therefore, in this review, we systematically summarize the molecular and cellular mechanisms involved in RILD. Such an analysis is essential for preventing the occurrence and development of RILD and further exploring the potential treatment of this disease.

Radiation-induced liver injury and hepatocyte senescence

Radiation-induced liver injury (RILI) is a major complication of radiotherapy during treatment for liver cancer and other upper abdominal malignant tumors that has poor pharmacological therapeutic options. A series of pathological changes can be induced by radiation. However, the underlying mechanism of RILI remains unclear. Radiation can induce cell damage via direct energy deposition or reactive free radical generation. Cellular senescence can be observed due to the DNA damage response (DDR) caused by radiation. The senescence-associated secretory phenotype (SASP) secreted from senescent cells can cause chronic inflammation and aggravate liver dysfunction for a long time. Oxidative stress further activates the signaling pathway of the inflammatory response and affects cellular metabolism. miRNAs clearly have differential expression after radiation treatment and take part in RILI development. This review aims to systematically profile the overall mechanism of RILI and the effects of radiation on hepatocyte senescence, laying foundations for the development of new therapies.

Protective rules of natural antioxidants against gamma-induced damage-A review

Phytochemicals accessible in food have demonstrated efficiency against impairment by gamma radiation. The review presented here is an attempt to show the pharmacological outline of the activity of the natural antioxidants and its primary action of molecular mechanism against the damage induced by gamma rays. This research focused on the results of the in vitro dosage of natural antioxidants relationship, and on the correlation of this information with the statistical variables. Moreover, it deliberated the natural compounds which could decrease the unwelcome impacts of gamma radiation and safeguard biological systems from radiation-stimulated genotoxicity. The outcomes indicated that natural compounds can be utilized as an adjunct to orthodox radiotherapy and cultivate it as an effectual drug for the clinical administration of ailments.

Long and short non-coding RNA and radiation response: a review

Once thought of as arising from "junk DNA," noncoding RNAs (ncRNAs) have emerged as key molecules in cellular processes and response to stress. From diseases such as cancer, coronary artery disease, and diabetes to the effects of ionizing radiation (IR), ncRNAs play important roles in disease progression and as biomarkers of damage. Noncoding RNAs regulate cellular processes by competitively binding DNA, mRNA, proteins, and other ncRNAs. Through these interactions, specific ncRNAs can modulate the radiosensitivity of cells and serve as diagnostic and prognostic biomarkers of radiation damage, whether from incidental exposure in radiotherapy or in accidental exposure scenarios. Analysis of RNA expression after radiation exposure has shown alterations not only in mRNAs, but also in ncRNAs (primarily miRNA, circRNA, and lncRNA), implying an important role in cellular stress response. Due to their abundance and stability in serum and other biofluids, ncRNAs also have great potential as minimally invasive biomarkers with advantages over current biodosimetry methods. Several studies have examined changes in ncRNA expression profiles in response to IR and other forms of oxidative stress. Furthermore, some studies have reported modulation of radiosensitivity by altering expression levels of these ncRNAs. This review discusses the roles of ncRNAs in the radiation response and evaluates prior research on ncRNAs as biomarkers of radiation damage. Future directions and applications of ncRNAs in radiation research are introduced, including the potential for a clinical ncRNA assay for assessing radiation damage and for the therapeutic use of RNA interference (RNAi).

MicroRNA: a novel implication for damage and protection against ionizing radiation

Ionizing radiation (IR) is a form of high energy. It poses a serious threat to organisms, but radiotherapy is a key therapeutic strategy for various cancers. It is significant to reduce radiation injury but maximize the effect of radiotherapy. MicroRNAs (miRNAs) are posttranscriptionally regulatory factors involved in cellular radioresponse. In this review, we show how miRNAs regulate important genes on cellular response to IR-induced damage and how miRNAs participate in IR-induced carcinogenesis. Additionally, we summarize the experimental and clinical evidence for miRNA involvement in radiotherapy and discuss their potential for improvement of radiotherapy. Finally, we highlight the role that miRNAs play in accident exposure to IR or radiotherapy as predictive biomarker. miRNA therapeutics have shown great perspective in radiobiology; miRNA may become a novel strategy for damage and protection against IR.

RNA Profiling Reveals a Common Mechanism of Histone Gene Downregulation and Complementary Effects for Radioprotectants in Response to Ionizing Radiation

High-dose ionizing radiation (IR) alters the expression levels of non-coding RNAs (ncRNAs). However, the roles of ncRNAs and mRNAs in mediating radiation protection by radioprotectants remain unknown. Microarrays were used to determine microRNA (miRNA), long ncRNA (lncRNA), and mRNA expression profiles in the bone marrow of irradiated mice pretreated with amifostine, CBLB502, and nilestriol. Differentially expressed mRNAs were functionally annotated by Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analyses. Some histone cluster genes were validated by real-time PCR, and the effects of radioprotectant combinations were monitored by survival analysis. We found that these radioprotectants increased the induction of lncRNAs and mRNAs. miRNA, lncRNA, and mRNA expression patterns were similar with amifostine and CBLB502, but not nilestriol. The radioprotectants exhibited mostly opposite effects against IR-induced miRNAs, lncRNAs, and mRNAs while inducing a common histone gene downregulation following IR, mainly via nucleosome assembly and related signaling pathways. Notably, the effects of nilestriol significantly complemented those of amisfostine or CBLB502; low-dose drug combinations resulted in better radioprotective effects in pretreated mice. Thus, we present histone gene downregulation by radioprotectants, together with the biological functions of miRNA, lncRNA, and mRNA, to explain the mechanism underlying radioprotection.

Effect of simulated microgravity and ionizing radiation on expression profiles of miRNA, lncRNA, and mRNA in human lymphoblastoid cells

In space, multiple unique environmental factors, particularly microgravity and space radiation, pose a constant threat to astronaut health. MicroRNAs (miRNAs) and long noncoding RNAs (lncRNAs) are functional RNAs that play critical roles in regulating multiple cellular processes. To gain insight into the role of non-coding RNAs in response to radiation and microgravity, we analyzed RNA expression profiles in human lymphoblastoid TK6 cells incubated for 24 h under static or rotating conditions to stimulate microgravity in space, after 2-Gy γ-ray irradiation. The expression of 14 lncRNAs and 17 mRNAs (differentially-expressed genes, DEGs) was found to be significantly downregulated under simulated microgravity conditions. In contrast, irradiation upregulated 55 lncRNAs and 56 DEGs, whereas only one lncRNA, but no DEGs, was downregulated. Furthermore, two miRNAs, 70 lncRNAs, and 87 DEGs showed significantly altered expression in response to simulated microgravity after irradiation, and these changes were independently induced by irradiation and simulated microgravity. GO enrichment and KEGG pathway analyses indicated that the associated target genes showed similar patterns to the noncoding RNAs and were suggested to be involved in the immune/inflammatory response including LPS/TLR, TNF, and NF-κB signaling pathways. However, synergistic effects on RNA expression and cellular responses were also observed with a combination of simulated microgravity and irradiation based on microarray and RT-PCR analysis. Together, our results indicate that simulated microgravity and irradiation additively alter expression patterns but synergistically modulate the expression levels of RNAs and their target genes in human lymphoblastoid cells.

Radioprotection of EGCG based on immunoregulatory effect and antioxidant activity against 60Coγ radiation-induced injury in mice

Excessive reactive oxygen radicals (ROS) produced by ionizing radiation (IR) can cause human body to serious oxidative damage, leading to oxidation-reduction (REDOX) system imbalance and immune system damage. Here, the radioprotection of EGCG was studied through a model of oxidative damage in ⁶⁰Coγ radiation mice. Firstly, the weights and the main organs indexes of mice, including the liver index, spleen index and pancreas index, indicated preliminarily the safety and protection of EGCG. Then, the radioprotection of EGCG based on immune-regulation on radiation mice was further investigated. Results suggested that EGCG could prevent significantly the immune system damage caused by ⁶⁰Coγ via increasing the immune organ index, inducing the transformation of spleen cells into T- and B-lymphocytes, and enhancing the macrophage phagocytosis, compared with model group. In addition, EGCG could also protect spleens of radiation mice from ⁶⁰Coγ-induced the imbalance of REDOX system by enhancing the activities of antioxidant enzymes superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px), increasing the level of glutathione (GSH), suppressing lipid peroxidation (Malondialdehyde, MDA). The antioxidant enzymes activities of serum and livers were also increased markedly. Taken together, our results indicated that EGCG possessed the excellent potential to serve as a natural radioprotector against IR-induced damage.

Large-scale quantitative genomics analyzes the circRNA expression profile and identifies the key circRNA in regulating cell proliferation during the proliferation phase of rat LR

Researchers have been exploring the genetic mechanisms underlying the control of liver regeneration (LR). However, an integrated analysis of circRNAs expression of rat regenerating livers during the proliferation phase has not been performed yet. For this purpose, circRNAs expression profile was globally analyzed by high-throughput sequencing. It showed that 10,003 circRNAs were detected, and 164 circRNAs were differentially expressed. Subsequently, 27 circRNAs were predicted to bind to 58 candidate miRNAs and compete for miRNA-binding sites with 2195 mRNAs. By applying GO and KEGG analysis, it was predicted that these circRNAs significantly participated in tissue regeneration, regulation of cell proliferation and Ras, p53, Wnt, Jak-STAT, MAPK signalling pathways. Based on the number of the corresponding miRNAs and their role enriched and reported in cell proliferation of LR or hepatocellular carcinoma, four kinds of circRNAs (circ_03848, circ_08236, circ_13398 and circ_15013) were considered as the key circRNAs. The predicted competing endogenous RNA networks and bioinformatics analysis revealed the potential role of these circRNAs in LR, which would provide useful information for understanding the mechanism of LR.

Proteomic Analysis of Radiation-Induced Acute Liver Damage in a Rabbit Model

Radiation-induced liver damage (RILD) has become a limitation in radiotherapy for hepatocellular carcinoma. We established a rabbit model of RILD by CyberKnife. Electron microscopy analysis revealed obvious nuclear atrophy and disposition of fat in the nucleus after irradiation. We then utilized a mass spectrometry-based label-free relative quantitative proteomics approach to compare global proteomic changes of rabbit liver in response to radiation. In total, 2365 proteins were identified, including 338 proteins that were significantly dysregulated between irradiated and nonirradiated liver tissues. These differentially expressed proteins included USP47, POLR2A, CSTB, MCFD2, and CSNK2A1. Real-time polymerase chain reaction confirmed that USP47 and CABLES1 transcripts were significantly higher in irradiated liver tissues, whereas MCFD2 and CSNK2A1 expressions were significantly reduced. In Clusters of Orthologous Groups of proteins analysis, differentially expressed proteins were annotated and divided into 24 categories, including posttranslational modification, protein turnover, and chaperones. Kyoto Encyclopedia of Genes and Genomes analysis revealed that the enriched pathways in dysregulated proteins included the vascular endothelial growth factors (VEGF) signaling pathway, the mitogen-activated protein kinase (MAPK) signaling pathway, and the adipocytokine signaling pathway. The identification of proteins and pathways is crucial toward elucidating the radiation response process of the liver, which may facilitate the discovery of novel therapeutic targets.

Radiation-Induced Reactions in The Liver - Modulation of Radiation Effects by Lifestyle-Related Factors

Radiation has a wide variety of effects on the liver. Fibrosis is a concern in medical fields as one of the acute effects of high-dose irradiation, such as with cancer radiotherapies. Cancer is also an important concern following exposure to radiation. The liver has an active metabolism and reacts to radiations. In addition, effects are modulated by many environmental factors, such as high-calorie foods or alcohol beverages. Adaptations to other environmental conditions could also influence the effects of radiation. Reactions to radiation may not be optimally regulated under conditions modulated by the environment, possibly leading to dysregulation, disease or cancer. Here, we introduce some reactions to ionizing radiation in the liver, as demonstrated primarily in animal experiments. In addition, modulation of radiation-induced effects in the liver due to factors such as obesity, alcohol drinking, or supplements derived from foods are reviewed. Perspectives on medical applications by modulations of radiation effects are also discussed.

Exosomal miR-7 Mediates Bystander Autophagy in Lung after Focal Brain Irradiation in Mice

This study investigated whether exosomal microRNA-7 (miR-7) mediates lung bystander autophagy after focal brain irradiation in mice. After 10 Gy or sham irradiation of mice brains, lung tissues were extracted for the detection of autophagy markers by immunohistochemistry, western blotting, and quantitative real-time reverse transcription PCR (qRT-PCR), meanwhile the brains were dissociated, the neuron/astrocyte/microglia/oligodendrocyte were isolated, and the miR-7 expression in each population were detected, respectively. A dual-luciferase reporter assay was developed to identify whether Bcl-2 is a target gene of miR-7. After 10 Gy or sham irradiation of astrocytes, exosomes were extracted, stained with Dil (1,1'-Dioctadecyl-3,3,3',3'-Tetramethylindocarbocyanine Perchlorate), and added into non-irradiated astrocytes. Meanwhile, Dil-stained exosomes released from 10 Gy or sham irradiated astrocytes were injected into LC3B-GFP mice via the tail vein. Lung tissues were then extracted for western blotting and qRT-PCR. Irradiation of mouse brains increased the LC3B-II/I ratio, Beclin-1 and miR-7 levels, while decreased the Bcl-2 level in non-irradiated lung tissue. Interestingly, brain irradiation remarkably increased the miR-7 expression in astrocyte and oligodendrocyte. MiR-7 significantly inhibited the luciferase activity of the wild-type Bcl-2-3′-untranslated regions (UTR) reporter vector, but not that of the Bcl-2-3′-UTR mutant vector, indicating that Bcl-2 is directly targeted by miR-7. In in vitro study, the addition of irradiated astrocyte-secreted exosomes increased the LC3B-II/I ratio, Beclin-1 and miR-7 levels, while decreased the Bcl-2 level in non-irradiated astrocytes. Further, the injection of irradiated astrocyte-secreted exosomes through the tail vein increased the lung LC3B-II/I ratio, Beclin-1 and miR-7 level, but decreased the Bcl-2 level in vivo. We concluded that exosomal miR-7 targets Bcl-2 to mediate distant bystander autophagy in the lungs after brain irradiation.

Emergence of miR-34a in radiation therapy

Expressions of many microRNAs (miRNAs) in response to ionizing radiation (IR) have already been investigated and some of them seem to play an important role in the tumor radioresistance, normal tissue radiotoxicity or as predictive biomarkers to radiation. miR-34a is an emerging miRNA in recent radiobiology studies. Here, we review this miR-34 family member by detailing its different roles in radiation response and we will discuss about the role that it can play in radiation treatment. Thus, we will show that IR regulates miR-34a by increasing its expression. We will also highlight different biological processes involved in cellular response to IR and regulated by miR-34a in order to demonstrate the role it can play in tumor radio-response or normal tissue radiotoxicity as a radiosensitizer or radioprotector. miR-34a is poised to assert itself as an important player in radiobiology and should become more and more important in radiation therapy management.

Discovery and characterization of miRNAs in mouse thymus responses to ionizing radiation by deep sequencing

To investigate the potential regulatory roles of microRNA (miRNA) in mouse response to ionizing radiation (IR)-induced thymus injury, miRNA expression profiles of mouse thymus with or without IR were analyzed using deep sequencing technology. Potential target candidates of the identified miRNA were predicted using RNAhybrid and miRanda. Differently expressed miRNA targets functional annotation and pathways were noted using Swiss-Prot, Gene Ontology (GO), Clusters of Orthologous Groups (COG), Kyoto Encyclopedia of Genes and Genomes (KEGG) and non-redundant (NR) databases. In this study, there were 112 differently expressed miRNAs identified, including 45 known mature and 67 novel miRNAs, which meanwhile contained 77 up-regulated and 35 down-regulated miRNAs. The results of quantitative RT-polymerase chain reaction (qRT-PCR) verification were in agreement with the sequencing analysis. And the target genes of miRNA were annotated. These results revealed the differences of miRNA expression, further extended the biological knowledge and greatly facilitated future studies on the function of miRNA in IR-induced thymus injury.