Increased serum anti-CYP2E1 IgG autoantibody levels may be involved in the pathogenesis of occupational trichloroethylene hypersensitivity syndrome: a case-control study.

Occupational exposure to trichloroethylene (TCE) causes a systemic skin disorder with hepatitis known as TCE hypersensitivity syndrome (TCE-HS). Human Leukocyte Antigen (HLA)-B*13:01 is its susceptibility factor; however, the immunological pathogenesis of TCE-HS remains unknown. We herein examined the hypothesis that autoantibodies to CYP2E1 are primarily involved in TCE-HS. A case-control study of 80 TCE-HS patients, 186 TCE-tolerant controls (TCE-TC), and 71 TCE-nonexposed controls (TCE-nonEC) was conducted to measure their serum anti-CYP2E1 antibody (IgG) levels. The effects of TCE exposure indices, such as 8-h time-weighted-average (TWA) airborne concentrations, urinary metabolite concentrations, and TCE usage duration; sex; smoking and drinking habits; and alanine aminotransferase (ALT) levels on the antibody levels were also analyzed in the two control groups. There were significant differences in anti-CYP2E1 antibody levels among the three groups: TCE-TC > TCE-HS patients > TCE-nonEC. Antibody levels were not different between HLA-B*13:01 carriers and noncarriers in TCE-HS patients and TCE-TC. The serum CYP2E1 measurement suggested increased immunocomplex levels only in patients with TCE-HS. Multiple regression analysis for the two control groups showed that the antibody levels were significantly higher by the TCE exposure. Women had higher antibody levels than men; however, smoking, drinking, and ALT levels did not affect the anti-CYP2E1 antibody levels. Anti-CYP2E1 antibodies were elevated at concentrations lower than the TWA concentration of 2.5 ppm for TCE exposure. Since HLA-B*13:01 polymorphism was not involved in the autoantibody levels, the possible mechanism underlying the pathogenesis of TCE-HS is that TCE exposure induces anti-CYP2E1 autoantibody production, and HLA-B*13:01 is involved in the development of TCE-HS.

Effects of long sleep time and irregular sleep-wake rhythm on cognitive function in older people.

Sleep disturbances and cognitive decline are common in older adults. We aimed to investigate the effects of the total sleep time (TST) and sleep-wake rhythm on executive function and working memory in older adults. In 63 older participants, we measured the TST, wake after sleep onset (WASO), and sleep timing (midpoint between bedtime and wake-up time) using actigraphy. Executive function was evaluated with the trail making test B (TMT-B) and Wisconsin card sorting test (WCST). The number of back task (N-back task) was used to measure working memory. Participants with a TST ≥ 8 h had a significantly lower percentage of correct answers (% correct) on the 1-back task than those with a TST < 8 h. The % correct on the 1-back task was significantly correlated with the TST, WASO, and sleep timing. Multiple regression analyses revealed that the TST and sleep timing were significant factors of the % correct on the 1-back task. The TMT-B score was significantly correlated with the sleep timing. Category achievement on the WCST was significantly correlated with the standard deviation of the sleep timing. Therefore, a long sleep time and an irregular sleep-wake rhythm could have adverse effects on executive function and working memory in older people.

Peptides containing the MXXCW motif inhibit oncogenic RET kinase activity with a novel mechanism of action.

REarranged during Transition (RET) is a tyrosine kinase associated with the development of several malignancies. Identification of RET kinase inhibitors promises valuable therapeutic tools for the intervention of RET-driven tumors. Most currently available tyrosine kinase inhibitors target the ATP binding site, but there are several drawbacks of these ATP-competitive drugs. Therefore, there is a need to develop new kinase inhibitors with alternative mechanisms of action. We have previously reported that a conserved cysteine in the MXXCW motif of RET is crucial to the disulfide-bonded dimerization-linked activation of RET kinases. Reagents which bind to this cysteine may inhibit the activity of RET kinases through disulfide-bond mediated dimerization. Here, we examine the potential of MXXCW motif-containing peptides as candidate kinase inhibitors. We demonstrate that MXXCW motif-containing peptides bind to RET in a redox-sensitive manner and block enzymatic activity, causing inhibition of the RET-dependent activity of extracellular signal-regulated kinases and effectively reducing the malignant potential of RET-papillary thyroid carcinoma-1 (PTC)-expressing cells. These motif-containing peptides were also found to be effective against the drug resistant mutant of RET. The inhibition of RET kinase activity by these peptides resulted in suppression of RET-PTC-1-mediated cancer growth. The great potency of these cysteine targeted peptides could indicate promising approaches for novel molecular-targeted therapies for RET-associated cancers.

Inhibition of mast cell degranulation by melanin.

Melanin is a dark naturally occurring pigment produced in nature and in many organisms. Although several reports have demonstrated applications for melanins in various therapeutic treatments, to date, no research has examined the anti-allergic effect of melanin. In this study, we for the first time found that solubilized or synthesized soluble melanin acts as a potent inhibitor of the degranulation of mast cells. We found that squid-ink-derived melanin significantly inhibited antigen-IgE-FcεRI-mediated degranulation of the mucosal mast cell line RBL-2H3. A homogenized melanin nanoparticle prepared by laser ablation also clearly suppressed antigen-induced mast cell degranulation. We also successfully solubilized synthetic melanin in a neutral biochemical buffer and found that it also significantly inhibited IgE-sensitized mast cells. The anti-degranulation activity of synthesized melanin was abolished in the melanin fraction below 50-kD molecular weight. All melanins used in this study did not exert significant cell death. Signal transduction analysis revealed that melanin suppressed antigen-triggered phosphorylation of signaling molecules as well as calcium influx. Transmission electron microscopy revealed that homogenized melanin nanoparticles partially attached to the cell surface and some nanoparticles were internalized to the cell. Flow cytometry revealed that the number of FcεRI-bound IgE molecules was decreased by melanin. Fluorescence recovery after photobleaching analysis indicated that melanin attenuated both plasma membrane and cytoplasmic fluidity, implying that melanin increased their viscosities. In vivo experiments using passive systemic anaphylaxis (PSA) and passive cutaneous anaphylaxis (PCA) mouse models demonstrated that oral administration of melanin accelerated the recovery of decreased body temperature after antigen infection in PSA, and combination sensitization of IgE with melanin attenuated antigen-induced extravasation in PCA. These findings indicated that melanin exhibits preventative effects against IgE-mast cell-mediated anaphylaxis. This study provides the first evidence that homogenized melanin may be a potential therapeutic agent for diseases involving mast cells.

Hydrogen gas improves left ventricular hypertrophy in Dahl rat of salt-sensitive hypertension.

PURPOSE: Hypertension is an important risk factor for death resulting from stroke, myocardial infarction, and end-stage renal failure. Hydrogen (H2) gas protects against many diseases, including ischemia-reperfusion injury and stroke. The effects of H2 on hypertension and its related left ventricular (LV) function have not been fully elucidated. The purpose of this study was to investigate the effects of H2 gas on hypertension and LV hypertrophy using echocardiography. METHODS: Dahl salt-sensitive (DS) rats were randomly divided into three groups: those fed an 8% NaCl diet until 12 weeks of age (8% NaCl group), those additionally treated with 2% H2 gas (8% NaCl + 2% H2 group), and control rats maintained on a diet containing 0.3% NaCl until 12 weeks of age (0.3% NaCl group). H2 gas was supplied through a gas flowmeter and delivered by room air (2% hydrogenated room air, flow rate of 10 L/min) into a cage surrounded by an acrylic chamber. We evaluated interventricular septal wall thickness (IVST), LV posterior wall thickness (LVPWT), and LV mass using echocardiography. RESULTS: IVST, LVPWT, and LV mass were significantly higher in the 8% NaCl group than the 0.3% NaCl group at 12 weeks of age, whereas they were significantly lower in the 8% NaCl + 2% H2 group than the 8% NaCl group. There was no significant difference in systolic blood pressure between the two groups. CONCLUSION: Our findings suggest that chronic H2 gas inhalation may help prevent LV hypertrophy in hypertensive DS rats.

Improvement of balance in young adults by a sound component at 100 Hz in music.

About 80% of young people use personal listening devices (PLDs) including MP3 players to listen to music, which consists of sound components with various frequencies. Previous studies showed that exposure to noise of high intensities affected balance in humans. However, there is no information about a frequency-dependent effect of sound components in music from a PLD on balance in young people. In this study, we determined the associations between sound component levels (dB) at 100, 1000 and 4000 Hz in music from a portable listening device (PLD) and balance objectively determined by posturography in young adults (n = 110). We divided the subjects into two groups (low and high exposure groups) based on cut-off values of sound component levels at each frequency using receiver operating characteristic (ROC) curves. Balance in the high exposure group (≥46.6 dB) at 100 Hz was significantly better than that in low exposure group in logistic regression models adjusted for sex, BMI, smoking status and alcohol intake, while there were no significant associations at 1000 and 4000 Hz. Thus, this study demonstrated for the first time that the sound component at 100 Hz with more than 46.6 dB in music improved balance in young adults.

Prevention of allergic rhinitis by ginger and the molecular basis of immunosuppression by 6-gingerol through T cell inactivation.

The incidence of allergies has recently been increasing worldwide. Immunoglobulin E (IgE)-mediated hypersensitivity is central to the pathogenesis of asthma, hay fever and other allergic diseases. Ginger (Zingiber officinale Roscoe) and its extracts have been valued for their medical properties including antinausea, antiinflammation, antipyresis and analgesia properties. In this study, we investigated the antiallergic effects of ginger and 6-gingerol, a major compound of ginger, using a mouse allergy model and primary/cell line culture system. In mice with ovalbumin (OVA)-induced allergic rhinitis, oral administration of 2% ginger diet reduced the severity of sneezing and nasal rubbing by nasal sensitization of OVA and suppressed infiltration of mast cells in nasal mucosa and secretion of OVA-specific IgE in serum. 6-Gingerol inhibited the expression of not only Th2 cytokines but also Th1 cytokines in OVA-sensitized spleen cells. Accordingly, 6-gingerol suppressed in vitro differentiation of both Th1 cells and Th2 cells from naïve T cells. In addition, 6-gingerol suppressed both superantigen staphylococcal enterotoxin B (SEB)- and anti-CD3-induced T cell proliferation. 6-Gingerol also abrogated PMA plus ionomycin- and SEB-induced IL-2 production in T cells, suggesting that 6-gingerol affected T cell receptor-mediated signal transduction rather than the antigen-presentation process. Indeed, 6-gingerol inhibited the phosphorylation of MAP kinases, calcium release and nuclear localization of c-fos and NF-κB by PMA and ionomycin stimulation. Thus, our results demonstrate that 6-gingerol suppresses cytokine production for T cell activation and proliferation, thereby not causing B cell and mast cell activation and resulting in prevention or alleviation of allergic rhinitis symptoms.

Correlated expression levels of endothelin receptor B and Plexin C1 in melanoma.

Discussion concerning the effect of endothelin receptor B (Ednrb) on melanoma continues because Ednrb has been reported to have both tumor promoting and suppressive effects for melanoma. In order to examine Ednrb-related signaling in melanomagenesis, DNA microarray analysis for a melanoma from a RFP/RET-transgenic mouse (RET-mouse) and a melanoma from an Ednrb-heterozygously deleted RET-mouse [Ednrb(+/-);RET-mouse], in both of which melanoma spontaneously develops, was performed in this study. We found that the expression level of Plexin C1 (PlxnC1), a suppressor for melanoma, in a melanoma from an Ednrb(+/-);RET-mouse was drastically decreased compared to that in a melanoma from a RET-mouse. Therefore, we further examined the correlation between Ednrb and PlxnC1 expression levels in melanomas. PlxnC1 transcript expression levels in melanomas from Ednrb(+/-);RET-mice were lower than those in melanomas from RET-mice. A strong correlation between Ednrb and PlxnC1 transcript expression levels (R = 0.78, p < 0.01) was also found in melanomas from both RET-mice and Ednrb(+/-);RET-mice. Correspondingly, there was a significant correlation between transcript (R = 0.80; p < 0.01) and protein (R = 0.60; p < 0.01) expression levels of EDNRB and PLXNC1 in human primary melanomas. Together with our results showing that the expression level of PLXNC1 transcript was reduced in EDNRB-depleted human melanoma cells, our results showing positively correlated expression levels of Ednrb/EDNRB and PlxnC1/PLXNC1 in melanoma suggest that PlxnC1/PLXNC1 is involved in the Ednrb/EDNRB-mediated suppressive effect on melanoma.

Non-thermal atmospheric pressure plasmas as a novel candidate for preventive therapy of melanoma.

Due to the increased ultraviolet radiation, the incidence of melanoma is increasing worldwide more than that of any other cancer. In this study, the effects of irradiation of non-thermal atmospheric pressure plasmas (NEAPPs) on benign melanocytic tumors from our original hairless model mice (HL-RET-mice), in which benign melanocytic tumors and melanomas spontaneously develop in the skin stepwise, were examined. Expression levels of melanoma cell adhesion molecule (MCAM) and matrix metalloproteinase-2 (MMP-2) mRNA in melanomas were higher than those in benign melanocytic tumors in the mice. Repeated irradiation of non-thermal atmospheric pressure plasmas (NEAPPs) for the benign tumors decreased the expression levels of MCAM and MMP-2 mRNA in the tumors from the mice. Previous studies showed that MCAM sites are upstream of MMP-2, that MCAM regulates transcription of MMP-2 in melanoma cells and that MMP-2 is associated with the conversion of a benign tumor to a malignant tumor. Therefore, our results suggest that the NEAPP irradiation-mediated decrease in the expression level of MMP-2 in benign melanocytic tumors is associated with decreased expression levels of MCAM. Moreover, NEAPP irradiation might be a potential candidate for therapy to prevent melanoma development through suppression of malignant conversion in benign melanocytic tumors.

Transient decline in hippocampal theta activity during the acquisition process of the negative patterning task.

Hippocampal function is important in the acquisition of negative patterning but not of simple discrimination. This study examined rat hippocampal theta activity during the acquisition stages (early, middle, and late) of the negative patterning task (A+, B+, AB-). The results showed that hippocampal theta activity began to decline transiently (for 500 ms after non-reinforced stimulus presentation) during the late stage of learning in the negative patterning task. In addition, this transient decline in hippocampal theta activity in the late stage was lower in the negative patterning task than in the simple discrimination task. This transient decline during the late stage of task acquisition may be related to a learning process distinctive of the negative patterning task but not the simple discrimination task. We propose that the transient decline of hippocampal theta activity reflects inhibitory learning and/or response inhibition after the presentation of a compound stimulus specific to the negative patterning task.

Transient decline in rats' hippocampal theta power relates to inhibitory stimulus-reward association.

The hippocampus is important in learning during a discrimination-reversal task. In this task, animals first learn to emit the go response to one stimulus and the no-go response to another stimulus (S1+, S2-) during the discrimination phase, and then they learn to reverse these relationships between stimulus and response during the reversal phase (S1-, S2+). To emit a no-go response for non-reinforced trial during the reversal phase, animals needed to inhibit the previously learned response pattern. This study examined the relationship between the reversal phase of the discrimination-reversal task and hippocampal electric activity in operant conditioning. The results revealed that hippocampal theta power transiently declined during the non-reinforced trial in the reversal phase compared with that during the discrimination phase. This decrease was observed during the 400-600-ms epoch after the onset of stimulus presentation. This study suggested that transient decline in hippocampal theta power is related to negative memory retrieval.

Neural activity in the hippocampus during conflict resolution.

This study examined configural association theory and conflict resolution models in relation to hippocampal neural activity during positive patterning tasks. According to configural association theory, the hippocampus is important for responses to compound stimuli in positive patterning tasks. In contrast, according to the conflict resolution model, the hippocampus is important for responses to single stimuli in positive patterning tasks. We hypothesized that if configural association theory is applicable, and not the conflict resolution model, the hippocampal theta power should be increased when compound stimuli are presented. If, on the other hand, the conflict resolution model is applicable, but not configural association theory, then the hippocampal theta power should be increased when single stimuli are presented. If both models are valid and applicable in the positive patterning task, we predict that the hippocampal theta power should be increased by presentation of both compound and single stimuli during the positive patterning task. To examine our hypotheses, we measured hippocampal theta power in rats during a positive patterning task. The results showed that hippocampal theta power increased during the presentation of a single stimulus, but did not increase during the presentation of a compound stimulus. This finding suggests that the conflict resolution model is more applicable than the configural association theory for describing neural activity during positive patterning tasks.

Hippocampal theta wave activity during configural and non-configural tasks in rats.

This study examined hippocampal theta power during configural and non-configural tasks in rats. Experiment 1 compared hippocampal theta power during a negative patterning task (A+, B+, AB-) to a configural task and a simple discrimination task (A+, B-) as a non-configural task. The results showed that hippocampal theta power during the non-reinforcement trial (non-RFT) of the negative patterning task was higher than that during the simple discrimination task. However, this hippocampal power may reflect sensory processing for compound stimuli that have cross-modality features (the non-RFT of the negative patterning task was presented together with visual and auditory stimuli, but the non-RFT of the simple discrimination task was presented with visual or auditory stimulus alone). Thus, in experiment 2, we examined whether the experiment 1 results were attributable to sensory processing of a compound stimulus by comparing hippocampal theta power during negative patterning (A+, B+, AB-), simultaneous feature-negative (A+, AB-), and simple discrimination tasks (A+, B-). Experiment 2 showed that hippocampal theta activity during the non-RFT in the negative patterning task was higher than that in the simultaneous feature-negative and simple discrimination tasks. Thus, we showed that hippocampal theta activity increased during configural tasks but not during non-configural tasks.

RAS/RAF/MEK/ERK and PI3K/PTEN/AKT Signaling in Malignant Melanoma Progression and Therapy.

Cutaneous malignant melanoma is one of the most serious skin cancers and is highly invasive and markedly resistant to conventional therapy. Melanomagenesis is initially triggered by environmental agents including ultraviolet (UV), which induces genetic/epigenetic alterations in the chromosomes of melanocytes. In human melanomas, the RAS/RAF/MEK/ERK (MAPK) and the PI3K/PTEN/AKT (AKT) signaling pathways are two major signaling pathways and are constitutively activated through genetic alterations. Mutations of RAF, RAS, and PTEN contribute to antiapoptosis, abnormal proliferation, angiogenesis, and invasion for melanoma development and progression. To find better approaches to therapies for patients, understanding these MAPK and AKT signaling mechanisms of melanoma development and progression is important. Here, we review MAPK and AKT signaling networks associated with melanoma development and progression.

Molecular Network Associated with MITF in Skin Melanoma Development and Progression.

Various environmental and genetic factors affect the development and progression of skin cancers including melanoma. Melanoma development is initially triggered by environmental factors including ultraviolet (UV) light, and then genetic/epigenetic alterations occur in skin melanocytes. These first triggers alter the conditions of numerous genes and proteins, and they induce and/or reduce gene expression and activate and/or repress protein stability and activity, resulting in melanoma progression. Microphthalmia-associated transcription factor (MITF) is a master regulator gene of melanocyte development and differentiation and is also associated with melanoma development and progression. To find better approaches to molecular-based therapies for patients, understanding MITF function in skin melanoma development and progression is important. Here, we review the molecular networks associated with MITF in skin melanoma development and progression.

Control of genetically prescribed protein tyrosine kinase activities by environment-linked redox reactions.

Recent observations on environment-linked control of genetically prescribed signaling systems for either cell activation or cell death have been reviewed with a focus on the regulation of activities of protein tyrosine kinases (PTKs). The environment-linked redox reactions seem to primarily affect cell surface receptors and cell membrane lipid rafts, and they induce generation of reactive oxygen species (ROS) in cells. ROS thus generated might upregulate the catalytic activities of PTKs through inactivating protein tyrosine phosphatases that dephosphorylate and inactivate autophosphorylated PTKs. Recent evidence has, however, demonstrated that ROS could also directly oxidize SH groups of genetically conserved specific cysteines on PTKs, sometimes producing disulfide-bonded dimers of PTK proteins, either for upregulation or downregulation of their catalytic activities. The basic role of the redox reaction/covalent bond-mediated modification of protein tertiary structure-linked noncovalent bond-oriented signaling systems in living organisms is discussed.

L-cysteine as a regulator for arsenic-mediated cancer-promoting and anti-cancer effects.

Previous studies have shown that activities of tyrosine kinases and secretion of the active form of matrix metalloproteinase-2 (MMP-2) are correlated with promotion of tumor growth, while apoptotic cell death in cancer cells is correlated with anti-cancer effects. Although arsenic has been reported to have both cancer-promoting and anti-cancer effects, the mechanisms of the arsenic-mediated bidirectional effects remain unknown. We examined the effects of arsenic on both proto-oncogene c-RET-transfected NIH3T3 cells with benign characters and oncogenic RET-MEN2A-transfected NIH3T3 cells with malignant characters. Arsenic promoted not only c-RET tyrosine kinase activity but also genetically activated RET-MEN2A kinase activity with promotion of dimer formation of RET proteins. Arsenic also increased secretion of the active form of MMP-2 in both RET-MEN2A-transfectants and c-RET-transfectants. On the other hand, arsenic promoted poly-(ADP-ribose) polymerase (PARP) degradation and cell death in both malignant and non-malignant cells. Interestingly, l-cysteine inhibited the arsenic-mediated tumor-promoting effects (activation of kinases and MMP-2 secretion) but not arsenic-mediated anti-cancer effects (PARP degradation and cell death). Our results suggest redox-linked regulation of arsenic-mediated activities of kinases and MMP-2 secretion but not arsenic-mediated cell death. Our results also suggest that l-cysteine is an ideal supplement that inhibits arsenic-mediated tumor-promoting effects without affecting arsenic-mediated anti-cancer effects.

c-RET molecule in malignant melanoma from oncogenic RET-carrying transgenic mice and human cell lines.

Malignant melanoma is one of the most aggressive cancers and its incidence worldwide has been increasing at a greater rate than that of any other cancer. We previously reported that constitutively activated RFP-RET-carrying transgenic mice (RET-mice) spontaneously develop malignant melanoma. In this study, we showed that expression levels of intrinsic c-Ret, glial cell line-derived neurotrophic factor (Gdnf) and Gdnf receptor alpha 1 (Gfra1) transcripts in malignant melanomas from RET-transgenic mice were significantly upregulated compared with those in benign melanocytic tumors. These results suggest that not only introduced oncogenic RET but also intrinsic c-Ret/Gdnf are involved in murine melanomagenesis in RET-mice. We then showed that c-RET and GDNF transcript expression levels in human malignant melanoma cell lines (HM3KO and MNT-1) were higher than those in primary cultured normal human epithelial melanocytes (NHEM), while GFRa1 transcript expression levels were comparable among NHEM, HM3KO and MNT-1. We next showed c-RET and GFRa1 protein expression in HM3KO cells and GDNF-mediated increased levels of their phosphorylated c-RET tyrosine kinase and signal transduction molecules (ERK and AKT) sited potentially downstream of c-RET. Taken together with the finding of augmented proliferation of HM3KO cells after GDNF stimulation, our results suggest that GDNF-mediated c-RET kinase activation is associated with the pathogenesis of malignant melanoma.