Sendai virus C protein affects macrophage function, which plays a critical role in modulating disease severity during Sendai virus infection in mice.

Sendai virus (SeV) accessory protein C limits the generation of double-stranded RNAs, defective interfering RNAs, or both, during viral transcription and replication, thereby limiting interferon-ß production. Our recent in vitro analyses on murine macrophage cell lines demonstrated that this protein also contributes to restricting macrophage function, including the production of nitric oxide (NO) and inflammatory cytokines in addition to interferon-ß, in infected macrophages. This study showed that depletion of airway macrophages by clodronate-loaded liposomes led to the development of severe viral pneumonia in recombinant C gene-knockout SeV (SeV∆C)-infected mice, but did not modulate disease severity in wild-type SeV-infected mice. Furthermore, the severe disease observed in macrophage-depleted, SeV∆C-infected mice was associated with exacerbated virus replication in the lungs, leading to severe airway inflammation and pulmonary edema, indicating lung injury. These results suggested that the antimacrophage activity of SeV C protein might play a critical role in modulating lung injury and associated diseases caused by SeV.

Phospholipase A2 from bee venom increases poly(I:C)-induced activation in human keratinocytes.

Bee venom (BV) induces skin inflammation, characterized by erythema, blisters, edemas, pain and itching. Although BV has been found to have an inhibitory effect on toll-like receptors (TLRs), we here show that BV enhances keratinocyte responses to polyinosinic-polycytidylic acid [poly(I:C)], a ligand for TLR3. Our results revealed that the enhanced TLR activity was primarily induced by secretory phospholipase A2 (sPLA2), a component of BV (BV-sPLA2). PLA2 mediates the hydrolysis of membrane phospholipids into lysophospholipids and free fatty acids. We demonstrated that BV-sPLA2 increased the intracellular uptake of poly(I:C), phosphorylation of the nuclear factor-kappa B (NF-κB) and mitogen-activated protein kinases (MAPKs), and poly(I:C)-mediated interleukin 8 production in human keratinocytes. We further showed that the enzymatic activity of BV-sPLA2 was essential for the increased uptake of poly(I:C). These findings suggest that BV-sPLA2 may induce a modification of the cell membrane structure, leading to enhanced poly(I:C) uptake in keratinocytes. BV-sPLA2 might be able to promote wound healing by enhancing TLR3 responses.

Screening siRNAs against host glycosylation pathways to develop novel antiviral agents against hepatitis B virus.

AIM: Hepatitis B virus (HBV) relies on glycosylation for crucial functions, such as entry into host cells, proteolytic processing and protein trafficking. The aim of this study was to identify candidate molecules for the development of novel antiviral agents against HBV using an siRNA screening system targeting the host glycosylation pathway. METHODS: HepG2.2.15.7 cells that consistently produce HBV were employed for our in vitro study. We investigated the effects of siRNAs that target 88 different host glycogenes on hepatitis B surface antigen (HBsAg) and HBV DNA secretion using the siRNA screening system. RESULTS: We identified four glycogenes that reduced HBsAg and/or HBV DNA secretion; however, the observed results for two of them may be due to siRNA off-target effects. Knocking down ST8SIA3, a member of the sialyltransferase family, significantly reduced both HBsAg and HBV DNA secretion. Knocking down GALNT7, which transfers N-acetylgalactosamine to initiate O-linked glycosylation in the Golgi apparatus, also significantly reduced both HBsAg and HBV DNA levels. CONCLUSIONS: These results showed that knocking down the ST8SIA3 and GALNT7 glycogenes inhibited HBsAg and HBV DNA secretion in HepG2.2.15.7 cells, indicating that the host glycosylation pathway is important for the HBV life cycle and could be a potential target for the development of novel anti-HBV agents.

Sendai Virus V Protein Inhibits the Secretion of Interleukin-1ß by Preventing NLRP3 Inflammasome Assembly.

Inflammasomes play a key role in host innate immune responses to viral infection by caspase-1 (Casp-1) activation to facilitate interleukin-1ß (IL-1ß) secretion, which contributes to the host antiviral defense. The NLRP3 inflammasome consists of the cytoplasmic sensor molecule NLRP3, adaptor protein ASC, and effector protein pro-caspase-1 (pro-Casp-1). NLRP3 and ASC promote pro-Casp-1 cleavage, leading to IL-1ß maturation and secretion. However, as a countermeasure, viral pathogens have evolved virulence factors to antagonize inflammasome pathways. Here we report that V gene knockout Sendai virus [SeV V(-)] induced markedly greater amounts of IL-1ß than wild-type SeV in infected THP1 macrophages. Deficiency of NLRP3 in cells inhibited SeV V(-)-induced IL-1ß secretion, indicating an essential role for NLRP3 in SeV V(-)-induced IL-1ß activation. Moreover, SeV V protein inhibited the assembly of NLRP3 inflammasomes, including NLRP3-dependent ASC oligomerization, NLRP3-ASC association, NLRP3 self-oligomerization, and intermolecular interactions between NLRP3 molecules. Furthermore, a high correlation between the NLRP3-binding capacity of V protein and the ability to block inflammasome complex assembly was observed. Therefore, SeV V protein likely inhibits NLRP3 self-oligomerization by interacting with NLRP3 and inhibiting subsequent recruitment of ASC to block NLRP3-dependent ASC oligomerization, in turn blocking full activation of the NLRP3 inflammasome and thus blocking IL-1ß secretion. Notably, the inhibitory action of SeV V protein on NLRP3 inflammasome activation is shared by other paramyxovirus V proteins, such as Nipah virus and human parainfluenza virus type 2. We thus reveal a mechanism by which paramyxovirus inhibits inflammatory responses by inhibiting NLRP3 inflammasome complex assembly and IL-1ß activation.IMPORTANCE The present study demonstrates that the V protein of SeV, Nipah virus, and human parainfluenza virus type 2 interacts with NLRP3 to inhibit NLRP3 inflammasome activation, potentially suggesting a novel strategy by which viruses evade the host innate immune response. As all members of the Paramyxovirinae subfamily carry similar V genes, this new finding may also lead to identification of novel therapeutic targets for paramyxovirus infection and related diseases.

Inflammatory responses increase secretion of MD-1 protein.

Radioprotective 105 (RP105) is a type I transmembrane protein, which associates with a glycoprotein, MD-1. Monoclonal antibody (mAb)-mediated ligation of RP105/MD-1 robustly activates B cells. RP105/MD-1 is structurally similar to Toll-like receptor 4 (TLR4)/MD-2. B-cell responses to TLR2 and TLR4/MD-2 ligands are impaired in the absence of RP105 or MD-1. In addition to RP105/MD-1, MD-1 alone is secreted. The structure of MD-1 shows that MD-1 has a hydrophobic cavity that directly binds to phospholipids. Little is known, however, about a ligand for MD-1 and the role of MD-1 in vivo To study the role of RP105/MD-1 and MD-1 alone, specific mAbs against MD-1 are needed. Here, we report the establishment and characterization of two anti-MD-1 mAbs (JR2G9, JR7G1). JR2G9 detects soluble MD-1, whereas JR7G1 binds both soluble MD-1 and the cell surface RP105/MD-1 complex. With these mAbs, soluble MD-1 was detected in the serum and urine. The MD-1 concentration was altered by infection, diet and reperfusion injury. Serum MD-1 was rapidly elevated by TLR ligand injection in mice. The quantitative PCR and supernatant-precipitated data indicate that macrophages are one of the sources of serum soluble MD-1. These results suggest that soluble MD-1 is a valuable biomarker for inflammatory diseases.

CLEC4M-positive and CD81-negative Huh7 cells are not susceptible to JFH-1 HCVcc infection but mediate transinfection.

C-type lectin domain family 4, member M (CLEC4M), a trans-membrane protein specifically expressed in liver sinusoidal endothelial cells, is considered a candidate receptor for hepatotropism of hepatitis C virus (HCV). CLEC4M was previously reported to capture artificial HCVpp (pseudoparticle) and transmit it to hepatocytes (transinfection) via CLEC4M-positive cells. It is still not known whether CLEC4M acts as a receptor for HCVcc (cell-culture-produced HCV) transinfection or whether CLEC4M is an entry receptor for HCVcc. Initially, we established stably CLEC4M-positive and HCV-replication-permissive cell lines by introducing a CLEC4M expression vector into Huh7-25 cells (Huh7-25-CLEC4M) by transfection. Huh7-25 is a mutant cell line that is resistant to JFH-1 HCVcc due to the lack of expression of CD81 but permissive for replication of JFH1 HCV RNA. When Huh7-25-CLEC4M cells were infected with HCVcc and cultured for 6 days, none were positive for infection. Next, to examine whether CLEC4M functions as a receptor for transinfection, Huh7-25-CLEC4M cells were inoculated with HCVcc and thereafter co-cultured with Huh7-it cells, which are susceptible to HCV infection. The amount of HCV RNA was increased in Huh7-it cells co-cultured with Huh7-25-CLEC4M cells, and the transinfection was inhibited in the presence of anti-CLEC4M antibody during inoculation. Thus, CLEC4M cannot substitute for CD81 as an entry receptor for JFH-1 HCVcc. It just mediates transinfection without internalization of HCVcc. CD81 is still crucial for HCV entry into hepatocytes, and CLEC4M in liver sinusoidal endothelial cells may be responsible for hepatotropism of HCV infection by trapping circulating HCV to transmit it to adjacent hepatocytes.

Human metapneumovirus M2-2 protein inhibits RIG-I signaling by preventing TRIM25-mediated RIG-I ubiquitination.

Retinoic acid-inducible gene I (RIG-I) is a receptor that senses viral RNA and interacts with mitochondrial antiviral signaling (MAVS) protein, leading to the production of type I interferons and inflammatory cytokines to establish an antiviral state. This signaling axis is initiated by the K63-linked RIG-I ubiquitination, mediated by E3 ubiquitin ligases such as TRIM25. However, many viruses, including several members of the family Paramyxoviridae and human respiratory syncytial virus (HRSV), a member of the family Pneumoviridae, escape the immune system by targeting RIG-I/TRIM25 signaling. In this study, we screened human metapneumovirus (HMPV) open reading frames (ORFs) for their ability to block RIG-I signaling reconstituted in HEK293T cells by transfection with TRIM25 and RIG-I CARD (an N-terminal CARD domain that is constitutively active in RIG-I signaling). HMPV M2-2 was the most potent inhibitor of RIG-I/TRIM25-mediated interferon (IFN)-ß activation. M2-2 silencing induced the activation of transcription factors (IRF and NF-kB) downstream of RIG-I signaling in A549 cells. Moreover, M2-2 inhibited RIG-I ubiquitination and CARD-dependent interactions with MAVS. Immunoprecipitation revealed that M2-2 forms a stable complex with RIG-I CARD/TRIM25 via direct interaction with the SPRY domain of TRIM25. Similarly, HRSV NS1 also formed a stable complex with RIG-I CARD/TRIM25 and inhibited RIG-I ubiquitination. Notably, the inhibitory actions of HMPV M2-2 and HRSV NS1 are similar to those of V proteins of several members of the Paramyxoviridae family. In this study, we have identified a novel mechanism of immune escape by HMPV, similar to that of Pneumoviridae and Paramyxoviridae family members.

SeV C Protein Plays a Role in Restricting Macrophage Phagocytosis by Limiting the Generation of Intracellular Double-Stranded RNA.

Macrophages play a central role in the innate immune response to respiratory viral infections through pro-inflammatory factor secretion and phagocytosis. However, as a countermeasure, viral pathogens have evolved virulence factors to antagonize macrophage function. In our recent in vitro analyses of murine macrophage cell lines, Sendai virus (SeV) accessory protein C inhibited the secretion of pro-inflammatory factors, and C gene-knockout SeV (SeVΔC) caused drastic morphological changes in RAW264.7 macrophages, similar to those observed after stimulation with Lipid A, a well-known activator of actin-rich membrane ruffle formation and phagocytosis. Hence, we sought to determine whether the C protein limits phagocytosis in SeV-infected macrophages through the suppression of membrane ruffling. Phagocytosis assays indicated an upregulation of phagocytosis in both SeVΔC-infected and Lipid A-stimulated macrophages, but not in SeV WT-infected cells. Further, the observed membrane ruffling was associated with phagocytosis. RIG-I is essential for Lipid A-induced phagocytosis; its deficiency inhibited SeVΔC-stimulated phagocytosis and ruffling, confirming the essential role of RIG-I. Moreover, treatment with interferon (IFN)-ß stimulation and neutralizing antibodies against IFN-ß suggested that SeVΔC-induced phagocytosis and ruffling occurred in an IFN-ß-independent manner. A newly isolated SeVΔC strain that does not generate dsRNA further highlighted the importance of dsRNA in the induction of phagocytosis and ruffling. Taken together, the current results suggest that SeV C protein might limit phagocytosis-associated membrane ruffling in an RIG-I-mediated but IFN-independent manner via limiting the generation of intracellular dsRNA.

Sendai virus V protein decreases nitric oxide production by inhibiting RIG-I signaling in infected RAW264.7 macrophages.

Sendai virus V protein is a known antagonist of RIG-I-like receptors (RLRs) RIG-I and MDA5, which activate transcription factors IRF3, leading to activation of ISGF3 and NF-κB. These transcription factors are known activators of inducible NO synthase (iNOS) and increase the production of nitric oxide (NO). By inhibiting ISGF3 and NF-κB, the V protein acts as an indirect negative regulator of iNOS and NO. Here we report that the V gene knockout Sendai virus [SeV V(-)] markedly enhanced iNOS expression and subsequent NO production in infected macrophages compared to wild-type SeV. The knockout of RIG-I in cells inhibited SeV V(-)-induced iNOS expression and subsequent NO production. To understand the underlying mechanism of the V protein-mediated negative regulation of iNOS activation, we transfected HEK293T cells with RIG-I and the RIG-I regulatory protein TRIM25. Our results demonstrated that the V protein inhibited iNOS activation via the RIG-I/TRIM25 pathway. Moreover, the V protein inhibited TRIM25-mediated K63-linked ubiquitination of RIG-I, as well as its CARD-dependent interaction with mitochondrial antiviral signaling (MAVS) molecules. These results suggest that the V protein downregulates iNOS activation and inhibits NO production by preventing the RIG-I-MAVS interaction, possibly through its effect on the ubiquitination status of RIG-I.

Variations in sensitivity to ionizing radiation in relation to p53 mutation point.

Mutation of p53 is the most common genetic alteration observed in human tumours and is reported to lead to variations in cell radiosensitivity. However, the relationship between the mutation point and the degree of radiosensitivity is unclear. Saos-2 cells with different mutations of p53 were prepared and examined for radiosensitivity. Cells with p53 mutations at codons 175, 244, 245, 273 and 282 were radioresistant, whereas those with mutations at codons 123, 195, 238 and 242 were radiosensitive. Mutations at codons 130, 143, 157, 168, 277, 280 and 286 resulted in medium radiosensitivity. Thus the sensitivity of Saos-2 cells to ionizing radiation varies with the mutation point of the p53 gene.

NF­κB inhibitor DHMEQ inhibits titanium dioxide nanoparticle­induced interleukin­1ß production: Inhibition of the PM2.5­induced inflammation model.

PM2.5 is a particle with a diameter <2.5 µm that is often involved in air pollution. Nanoparticles <100 nm are thought to invade the trachea and lungs to cause inflammation, possibly through the activation of macrophages. On the other hand, titanium dioxide (TiO2) particles can be used in models of nano­micro­sized particles, as one can prepare the particles with such sizes. TiO2 particles are classified into Rutile, Anatase, and Brookite types by their crystal structure. Among them, Anatase­type TiO2 particles with a primary diameter of 50 nm (A50) were reported to induce interleukin (IL)­1ß production and secretion effectively in phorbol 12­myristate 13­acetate­treated human monocytic leukemia THP­1 cells (THP­1 macrophages). We previously designed and synthesized dehydroxymethyl­epoxyqinomicin (DHMEQ) as an inhibitor of NF­κB. The present study investigated whether the NF­κB inhibitor DHMEQ inhibits TiO2 nanoparticle­induced IL­1ß production in THP­1 macrophages, and determined the mechanism. As a result, DHMEQ inhibited A50­induced IL­1ß secretion in ELISA assays at nontoxic concentrations. It decreased the expression of IL­1ß mRNA, which was dependent on NF­κB. Although NLR family pyrin domain containing 3 (NLRP3)­inflammasome­caspase­1 activation is required for the maturation of IL­1ß, and DHMEQ reduced the NLRP3 mRNA expression and caspase­1 activity; a caspase­1 inhibitor did not influence the A50­induced IL­1ß production. Therefore, it is likely that inhibition of pro­IL­1ß expression by DHMEQ may be sufficient to inhibit mature IL­1ß production. Thus, DHMEQ may be useful for the amelioration of inflammation in the trachea and lungs caused by inhalation of PM2.5.

Sendai virus C protein limits NO production in infected RAW264.7 macrophages.

To suppress virus multiplication, infected macrophages produce NO. However, it remains unclear how infecting viruses then overcome NO challenge. In the present study, we report the effects of accessory protein C from Sendai virus (SeV), a prototypical paramyxovirus, on NO output. We found that in RAW264.7 murine macrophages, a mutant SeV without C protein (4C(-)) significantly enhanced inducible NO synthase (iNOS) expression and subsequent NO production compared to wild type SeV (wtSeV). SeV 4C(-) infection caused marked production of IFN-ß, which is involved in induction of iNOS expression via the JAK-STAT pathway. Addition of anti-IFN-ß Ab, however, resulted in only marginal suppression of NO production. In contrast, NF-κB, a primarily important factor for transcription of the iNOS gene, was also activated by 4C(-) infection but not wtSeV infection. Induction of NO production and iNOS expression by 4C(-) was significantly suppressed in cells constitutively expressing influenza virus NS1 protein that can sequester double-stranded (ds)RNA, which triggers activation of signaling pathways leading to activation of NF-κB and IRF3. Therefore, C protein appears to suppress NF-κB activation to inhibit iNOS expression and subsequent NO production, possibly by limiting dsRNA generation in the context of viral infection.

Neutralizing Antibodies Induced by Gene-Based Hydrodynamic Injection Have a Therapeutic Effect in Lethal Influenza Infection.

The influenza virus causes annual epidemics and occasional pandemics and is thus a major public health problem. Development of vaccines and antiviral drugs is essential for controlling influenza virus infection. We previously demonstrated the use of vectored immune-prophylaxis against influenza virus infection. We generated a plasmid encoding neutralizing IgG monoclonal antibodies (mAbs) against A/PR/8/34 influenza virus (IAV) hemagglutinin (HA). We then performed electroporation of the plasmid encoding neutralizing mAbs (EP) in mice muscles and succeeded in inducing the expression of neutralizing antibodies in mouse serum. This therapy has a prophylactic effect against lethal IAV infection in mice. In this study, we established a new method of passive immunotherapy after IAV infection. We performed hydrodynamic injection of the plasmid encoding neutralizing mAbs (HD) involving rapid injection of a large volume of plasmid-DNA solution into mice via the tail vein. HD could induce neutralizing antibodies in the serum and in several mucosal tissues more rapidly than in EP. We also showed that a single HD completely protected the mice even after infection with a lethal dose of IAV. We also established other isotypes of anti-HA antibody (IgA, IgM, IgD, and IgE) and showed that like anti-HA IgG, anti-HA IgA was also effective at combating upper respiratory tract IAV infection. Passive immunotherapy with HD could thus provide a new therapeutic strategy targeting influenza virus infection.

Expression of CCR5 in graft-versus-host disease (GVHD) of the skin: immunohistochemical staining of 38 cases.

To ascertain the involvement of CCR5 in prolongation of graft-versus-host disease (GVHD), we performed immunohistochemical staining of CCR5 in 38 GVHD samples (23 acute and 15 chronic). A total of seven out of 15 cases of chronic GVHD were positive for CCR5; however, only two out of 23 in acute GVHD were positive for CCR5. In three cases, expression of CCR5 in infiltrating lymphocytes was negative in the acute phase, but positive in the chronic phase of GVHD. These findings suggest that the immunopathological mechanism that differentiates between acute and chronic GVHD is a CCR5-mediated immunoreaction.

Evaluation of fat-free mass by whole-body counter in Japanese healthy young adults.

Whole-body counters (WBCs) are special instruments for measuring internal irradiation doses and are usually housed within or around nuclear facilities in the event of unexpected radiation emergencies. As a substantial proportion of total body potassium (TBK) is found in fat-free mass (FFM), FFM volume can be predicted from WBC-measured (40)K. We screened TBK in Japanese healthy young adults using a WBC and found strong linear correlations between TBK and lean body mass (LBM) and body mass index (r = 0.97, P < 0.01 and r = 0.47, P < 0.01, respectively). Multiple linear regression analysis, following adjustments for sex, indicates that only LBM has a significant correlation with TBK (P < 0.01). These results strongly support the feasibility of using WBCs for estimating FFM.

C4b-binding protein negatively regulates TLR4/MD-2 response but not TLR3 response.

Recently, we reported a novel function for C4b-binding protein (C4BP) in inhibiting the toll-like receptor (TLR)1/2 response by interacting with TLR2. TLRs share a common structure; hence, we examined the effect of C4BP on activation of other TLRs-TLR4 and TLR3. The results of immunoprecipitation assays suggest that C4BP interacts with TLR4/MD-2 but not TLR3. C4BP inhibits TLR4/MD-2-mediated, but not TLR3-mediated, proinflammatory cytokine production and nuclear factor (NF)-κB signaling. C4BP-deficient mice show increased interleukin (IL)-6 production in response to the TLR4/MD-2 ligand. A competition assay revealed that C4BP prevents an interaction between TLR4/MD-2 and its ligand. These findings indicate that C4BP binds to cell surface TLRs and inhibits the TLR-TLR ligand interaction, thereby inhibiting TLR activation.

C4b binding protein negatively regulates TLR1/2 response.

TLR2 associates with TLR1 and recognizes microbial lipoproteins. Pam3CSK4, a triacylated lipoprotein, is anchored to the extracellular domain of TLR1 and TLR2 and induces pro-inflammatory signals. Here we show that C4b binding protein (C4BP), which is a complement pathway inhibitor, is a TLR2-associated molecule. Immunoprecipitation assay using anti-TLR2 mAb shows that C4BP binds to TLR2. In C4BP-deficient mice, Pam3CSK4-induced IL-6 levels were increased compared with wild type mice. In C4BP-expressing cells, Pam3CSK4-induced IL-8 production was reduced depending on the C4BP expression levels. These results reveal the important role of C4BP in negative regulation of TLR1/2-dependent pro-inflammatory cytokine production. Furthermore, using a fluorescent conjugated Pam3CSK4, we show that C4BP blocks the binding of Pam3CSK4 to TLR1/2. Finally, we show that exogenous C4BP also inhibits Pam3CSK4-induced signaling leading to IL-8 production. Our results indicate C4BP binding to TLR2 and consequent neutralization of its activity otherwise inducing pro-inflammatory cytokine production. C4BP is a negative regulator of TLR1/2 activity.

Measurement of the whole-body 137Cs in residents around the Chernobyl nuclear power plant.

To understand the current situation of internal radiation exposure in the population around the Chernobyl Nuclear Power Plant (CNPP), we examined the 137Cs body burden in six residents of Belarus, Ukraine and Russia in 2002 and 2004 using the whole-body counter (WBC) at Nagasaki University (Japan). The data were compared with those of our previous study performed in 1993-1994 using the same method. In 2002 and 2004, peaks of 137Cs were detected in two residents from Gomel, which was heavily contaminated by the CNPP accident, one from Minsk (Belarus) and one from Kiev (Ukraine), but another resident from Minsk showed no 137Cs peaks. The results of the present study suggests that residents around the CNPP are still exposed to chronic 137Cs internal irradiation, probably due to the daily consumption of contaminated domestic foods, but the risk of any disease by the irradiation is quite low. Long-term follow-up of WBC around the CNPP is useful and may contribute to radiation safety regulation together with a reduction of unnecessary radiophobia for the residents.

Low dose of wortmannin reduces radiosensitivity of human glioblastoma cells through the p53 pathway.

Wortmannin is an inhibitor of PI3-kinase and acts on cultured cells at dosages below 1 microM. Wortmannin also inhibits the gene products of the PI3-kinase family such as ATM or DNA-PK at dosages above 10 microM in cultured cells. There are many reports on the enhancement of radiosensitivity by a high dose of wortmannin inhibiting the proteins of the PI3-kinase family. However, there have been no reports on the effect on radiosensitivity of low doses of wortmannin inhibiting PI3-kinase. We found that low doses of wortmannin reduced the radiosensitivity of human A172 glioblastoma cells. This effect was shown only in wild-type p53 cells, but was not shown in mutant p53 cells such as T98G or A172/248W carrying a dominant point-mutated p53 gene. This result indicates that the PI3-kinase, or another wortmannin-sensitive enzyme, may affect the signal transduction of p53. We examined the response of the p53 pathway by X-ray irradiation. A low dose of wortmannin did not affect the accumulation of p53 and the phosphorylation of p53 at ser-15, but reduced the induction of WAF1 and enhanced the induction of GADD45.

[Assessment and control of health risk caused by the radiological accident at the TEPCO Fukushima Daiichi nuclear power plant].

The accident at the Tokyo Electric Power Company (TEPCO) Fukushima Daiichi nuclear power plant on March 11, 2011, released a large amount of radioactive materials resulting in the radioactive contamination of a wide area of eastern Japan. Residents of the Fukushima prefecture experienced various unavoidable damages and fear of radiation effects on their health. A reliable communication of accurate risk assessment for residents is required as a countermeasure aimed at the reconstruction of Fukushima. Here, the current status of individual dose estimation and the issues relating to the radiation risk perception are discussed.