Effects of Importin α1/KPNA1 deletion and adolescent social isolation stress on psychiatric disorder-associated behaviors in mice.

Importin α1/KPNA1 is a member of the Importin α family widely present in the mammalian brain and has been characterized as a regulator of neuronal differentiation, synaptic functionality, and anxiety-like behavior. In humans, a de novo mutation of the KPNA1 (human Importin α5) gene has been linked with schizophrenia; however, the precise roles of KPNA1 in disorder-related behaviors are still unknown. Moreover, as recent studies have highlighted the importance of gene-environment interactions in the development of psychiatric disorders, we investigated the effects of Kpna1 deletion and social isolation stress, a paradigm that models social stress factors found in human patients, on psychiatric disorder-related behaviors in mice. Through assessment in a behavioral battery, we found that Kpna1 knockout resulted in the following behavioral phenotype: (1) decreased anxiety-like behavior in an elevated plus maze test, (2) short term memory deficits in novel object recognition test (3) impaired sensorimotor gating in a prepulse inhibition test. Importantly, exposure to social isolation stress resulted in additional behavioral abnormalities where isolated Kpna1 knockout mice exhibited: (1) impaired aversive learning and/or memory in the inhibitory avoidance test, as well as (2) increased depression-like behavior in the forced swim test. Furthermore, we investigated whether mice showed alterations in plasma levels of stress-associated signal molecules (corticosterone, cytokines, hormones, receptors), and found that Kpna1 knockout significantly altered levels of corticosterone and LIX (CXCL5). Moreover, significant decreases in the level of prolactin were found in all groups except for group-housed wild type mice. Our findings demonstrate that Kpna1 deletion can trigger widespread behavioral abnormalities associated with psychiatric disorders, some of which were further exacerbated by exposure to adolescent social isolation. The use of Kpna1 knockout mice as a model for psychiatric disorders may show promise for further investigation of gene-environment interactions involved in the pathogenesis of psychiatric disorders.

Decreased Colonic Guanylin/Uroguanylin Expression and Dried Stool Property in Mice With Social Defeat Stress.

Psychological stress is deeply involved in the pathophysiology of not only mental illness but also functional gastrointestinal disorders. In the present study, we examined the relationship between psychological stress and abnormality of stool properties, focusing on the alteration of plasma glucocorticoid and guanylin (GN)/uroguanylin (UGN) expression in the colon. A murine model of chronic social defeat stress (CSDS) was established by exposing a C57BL/6N intruder mouse to a CD-1 aggressor mouse for 3-5 min. Thereafter the mice were kept in the same cage but separated by a divider for the remainder of the day. This procedure was repeated for 10 consecutive days, and then a social interaction test was performed to evaluate social avoidance. Fresh fecal and blood samples were collected for stool property analysis and measurement of the plasma glucocorticoid level by ELISA. The expression of GN, UGN, and guanylate cyclase 2C in the colonic tissues was examined by real-time RT-PCR and immunohistochemistry. Moreover, Lovo cells were stimulated with dexamethasone, and the expression of GN/UGN mRNA was examined. In the CSDS group, the time spent in the social interaction zone was significantly shorter when the CD-1 aggressor mouse was present than when it was absent. The social interaction ratio was also significantly lower in the CSDS group relative to the controls. The mean Bristol scale score was significantly lower in the CSDS group, but the fecal sodium concentration did not differ between CSDS mice and controls. The level of plasma corticosterone was significantly higher in the CSDS group than in the controls immediately after the 10th day of CSDS. The expression of both GN and UGN was significantly decreased in the CSDS mice. GN was expressed in all colonic epithelial cells, and UGN was expressed in ovoid or pyramidal epithelial cells in the colonic mucosa. The expression of both GN and UGN was significantly decreased in the CSDS mice relative to controls. The expression of both GN and UGN was significantly suppressed in Lovo cells upon stimulation with dexamethasone. Psychological stress-induced glucocorticoid may suppress colonic GN/UGN expression, resulting in a change in stool properties leading to constipation.

Stress-Induced Glucocorticoid Release Upregulates Uncoupling Protein-2 Expression and Enhances Resistance to Endotoxin-Induced Lethality.

OBJECTIVE: Although psychological and/or physiological stress has been well documented to influence immune responses, the precise mechanism for immunomodulation remains to be elucidated. The present work describes the role of the hypothalamic-pituitary-adrenal (HPA) axis in the mechanism of stress-mediated enhanced-resistance to lethality after lipopolysaccharide (LPS) injection. METHODS/RESULTS: Preconditioning with restraint stress (RS) resulted in enhanced activation of the HPA axis in response to LPS injection and suppressed LPS-induced release of proinflammatory cytokines and nitric oxide metabolites. Melanocortin 2 receptor-deficient mice (MC2R(-/-)) failed to increase plasma levels of glucocorticoids in response to LPS injection, and exhibited high sensitivity to LPS-induced lethality with enhanced release of proinflammatory cytokines as compared with MC2R(+/-) mice. Real-time PCR analysis revealed that RS induced upregulation of uncoupling protein-2 (UCP2) in macrophages in the lung and the liver of MC2R(+/-), but not of MC2R(-/-), mice. In addition, RS increased UCP2-dependent uncoupling activity of isolated mitochondria from the liver of MC2R(+/-), but not of MC2R(-/-), mice. In vitro study revealed that corticosterone and dexamethasone directly increased UCP2 expression in mouse RAW 264.7 macrophages and suppressed the generation of LPS-induced mitochondrial reactive oxygen species (ROS) and TNF-α production. Knockdown of UCP2 by small interfering RNA blunted the dexamethasone action for suppressing LPS-induced mitochondrial ROS and TNF-α production. CONCLUSION: The present work suggests that RS enhances activation of the HPA axis to release glucocorticoids and upregulation of UCP2 in macrophages, thereby increasing the resistance to endotoxin-induced systemic inflammation and death.

Delayed atrophy in posterior cingulate cortex and apathy after stroke.

OBJECTIVE: A few studies have been performed on chronic structural changes after stroke. The primary purpose of the present study was to investigate regional cortical volume changes after the onset of stroke and to examine how the cortical volume changes affected neuropsychiatric symptoms. METHODS: Participants were 20 stroke patients and 14 control subjects. T1-MRI was performed twice, once at the subacute stage and again 6 months later, and whole brain voxel-based morphometric (VBM) analysis was used to detect significant cortical gray matter volume changes in patients. We also assessed the correlation between changes in cortical volumes and changes in neuropsychiatric symptoms during the 6 months following a stroke. RESULTS: In the present study, we found significant volume reductions in the anterior part of the posterior cingulate cortex (PCC) over the 6 months following a stroke by exploratory VBM analysis. We also found that the amount of volume change was significantly correlated with the change in apathy-scale scores during the 6 months poststroke. CONCLUSIONS: The present study suggests that delayed atrophic change is evident in the PCC 6 months after a stroke. There was greater apathetic change in the stroke patients with the larger volume reductions. The delayed atrophy of the PCC may reflect degeneration secondary to neuronal loss due to stroke. Such degeneration might have impaired control of goal-directed behavior, leading to the observed increase in apathy.

Microstructural abnormality in white matter, regulatory T lymphocytes, and depressive symptoms after stroke.

BACKGROUND: The purpose of the present study was to investigate the existence of microstructure abnormalities in the white matter circuit in stroke patients and its relationship to depressive episodes. To target the prevention of depression, we also investigated the relationship between lymphocyte subsets and cerebral abnormalities in patients. METHODS: Participants included 18 patients with acute ischemic stroke and 22 healthy control subjects. Diffusion tensor imaging was performed. Whole-brain voxel-based analysis was used to compare fractional anisotropy (FA) between groups. Blood samples were obtained, and the lymphocyte subsets were evaluated using flow cytometry. Follow-up examinations were conducted on 12 patients at 6 months. RESULTS: FA was decreased in the bilateral anterior limb of the internal capsule in stroke patients. At the 6-month follow-up examination, there was a significant increase in FA, which was associated with a lower depression scale score. Patients showed a decreased percentage of circulated regulatory T lymphocytes, and the degree of reduction was related to the decrease in the FA value in the internal capsule. CONCLUSIONS: FA reductions in the anterior limb of the internal capsule cause abnormality in the frontal-subcortical circuits and confer a biological vulnerability, which in combination with environmental stressors results in the onset of depression. Our findings also demonstrated the possibility of preventing post-stroke depression by targeting the role of regulatory T lymphocytes in brain tissue repair and regeneration after stroke.

Microstructural abnormalities in white matter and their effect on depressive symptoms after stroke.

The aim of the study was to investigate the existence of microstructural abnormalities in the white matter of the brain in stroke patients, as well as the relationship between these microstructural abnormalities and changes in depressive symptoms over 6 months. Participants were 29 acute ischemic stroke patients and 37 healthy control subjects. Depressive symptoms were assessed in all subjects using the Hamilton Rating Scale for Depression and the Zung Self-rating Depression Scale. Whole brain voxel-based analysis was used to compare diffusion tensor imaging measures of Fractional Anisotropy (FA) between the groups. Six-month follow-up examinations were conducted. Patients showed significantly lower white matter FA values in the left and right anterior limbs of the internal capsule, and 6 months after the stroke they showed significantly increased FA values in these regions. We found a significant negative correlation between the increased ratio of the FA values and the change in depression scale scores at 6-month follow-up. Regional white matter damage may reflect abnormalities in neuroanatomical pathways related to the pathophysiology of depression.

Mild exercise suppresses exacerbation of dermatitis by increasing cleavage of the ß-endorphin from proopiomelanocortin in NC/Nga mice.

This study investigated the mechanism by which the strength and weakness of exercise stress affects the skin symptoms of atopic dermatitis (AD). Specific pathogen-free (SPF) and conventional NC/Nga mice were used. Conventional mice, but not the SPF, spontaneously develop dermal symptoms similar to that of patients with AD. There were two types of stress, mild (20 m/min for 60 min) or strong exercise (25 m/min for 90 min), using a treadmill four times per day. The symptom of the conventional group were strongly exacerbated by strong exercise but ameliorated by mild exercise. The plasma concentrations of α-melanocyte stimulating hormone (α-MSH) and the expression of melanocortin receptor-1 in skin elevated after strong exercise but decreased after mild exercise. The plasma levels of ß-endorphin and the expression of µ-opioid receptor in skin were increased by mild exercise. In addition, the expression of prohormone convertase (PC) 1/3, PC2 and carboxypeptidase E (CPE) in pituitary gland were higher in the conventional group than in the SPF group. The level of PC2 was suppressed by mild exercise in the conventional groups, and elevated further by strong exercise. The level of PC1/3 becomes higher with the increase of the exercise load. On the other hand, the expression of the CPE was further increase by mild exercise but suppressed by strong exercise. These observations suggested that exercise-induced stress significantly affect the symptoms of AD in a pivotal manner depending on the levels of α-MSH and ß-endorphin, and the expression of pituitary PC2 and CPE.

Potent immunomodulating effects of bran extracts of traditional Japanese millets on nitric oxide and cytokine production of macrophages (RAW264.7) induced by lipopolysaccharide.

To estimate the potent immunomodulating effects of different types of traditional Japanese millet, we analyzed the effect of bran extracts of foxtail millet (Awa in Japanese), barnyard millet (Hie) and proso millet (Mochi-kibi) on nitric oxide (NO) and inflammatory cytokine production induced by lipopolysaccharide (LPS) in a mouse macrophage cell line (RAW264.7 cells). All methanol extracts of these millet brans showed suppressive activities against the production of NO and inflammatory cytokines such as tumor necrosis factor-alpha (TNF-alpha) and interleukin (IL)-6 in LPS-stimulated macrophages, which were not responsible for their cytotoxic activities. These immunosuppressive activities were roughly proportional to the contents of the phenolic compounds in their extracts. Especially, the extract of proso millet exhibited the strongest immunosuppressing effect, which was associated with the highest content of phenolic compound. However, the extracts did not exhibit significant suppressive effects on the production of an anti-inflammatory cytokine, IL-10, in the same macrophage culture system. These results suggest that traditional Japanese millets have potent immunomodulating activities against the production of NO and cytokine production in activated macrophages.

A promoter variant in the chitinase 3-like 1 gene is associated with serum YKL-40 level and personality trait.

The chitinase 3-like 1 (CHI3L1) gene, a cellular survival factor against several environmental and psychosocial stresses, has been sown to be more highly expressed in the hippocampus and prefrontal cortex of patients with schizophrenia than unaffected individuals. We recently reported a significant association between schizophrenia and SNP rs4950928, which is located in the promoter region of the CHI3L1 gene, in a Japanese population. The G-allele at this SNP in the gene has been associated with higher transcriptional activity in a luciferase reporter assay and with higher mRNA levels in the peripheral blood cells of patients with schizophrenia. We investigated the impact of the CHI3L1 polymorphism rs4950928 on serum YKL-40 levels, the protein product of CHI3L1. We found that individuals with the G-allele, who were more prevalent among patients with schizophrenia, had significantly higher serum YKL-40 levels (p=0.043). Personality traits are considered to be an important aspect of schizophrenia primarily because they may influence symptoms and social functioning. Personality trait analyses using the temperament and character inventory (TCI) indicated that schizophrenic patients have a unique personality profile that appears to be present across cultures. We hypothesized that higher serum YKL-40 levels are associated with personality trait in patients with schizophrenia. Thus, we next examined the impact of the risk CHI3L1 polymorphism on personality traits using the TCI. We found that individuals with the G-allele had significantly higher self-transcendence scores (p=0.0054). These findings suggest possible associations between the SNP in the CHI3L1 gene, the risk for schizophrenia, and higher serum YKL-40 levels and personality traits in a Japanese population.

Inducible nitric oxide synthase (iNOS) and α-melanocyte-stimulating hormones of iNOS origin play important roles in the allergic reactions of atopic dermatitis in mice.

To elucidate the possible involvement of nitric oxide (NO) derived from inducible NO synthase (iNOS) in the pathogenesis of patients with allergic rhinitis, we used an animal model of atopic dermatitis (AD) induced by epicutaneous sensitization and analysed the differences in ear thickness, the frequency of scratching and plasma levels of ovalbumin-specific immunoglobulin E (OVA-IgE), transforming growth factor (TGF)-ß, tumor necrosis factor (TNF)-α, adrenocorticotropic hormone (ACTH) and α-melanocyte-stimulating hormone (α-MSH) between control and iNOS(-/-) mice. Eight-week-old control and iNOS(-/-) male C57BL/6j mice were sensitized three times with OVA antigen. Before and after the last skin sensitization, the number of scratching incidents and the thickness of the ear were examined, and the plasma levels of OVA-IgE, α-MSH, ACTH, TGF-ß and TNF-α were analysed by ELISA. Sensitization of mice with OVA resulted in increased plasma levels of OVA-IgE, α-MSH, ACTH, TGF-ß and TNF-α in control, but not in iNOS(-/-) mice. The administration of l-nitro-arginine-methyl ester (l-NAME) abolished all the above changes that occurred in the control mice. In addition, iNOS(-/-) mice given α-MSH exhibited a change similar to that seen in the control, whereas iNOS(-/-) mice given ACTH, TGF-ß or TNF-α did not demonstrate any changes. These results indicate that symptoms of AD such as scratching can be exacerbated by α-MSH, which is induced by iNOS-derived NO.

Physiological stress exacerbates murine colitis by enhancing proinflammatory cytokine expression that is dependent on IL-18.

Psychological stress is an environmental factor considered to be a precipitating factor of inflammatory bowel disease. Interleukin (IL)-18 plays a role in stress-induced aggravation in some diseases. The aim of this study was to establish a model of murine colitis exacerbated by psychological stress and to clarify the role of IL-18 in this model. Male C57Bl/6 mice and IL-18(-/-) mice were used for this study. The mice received dextran sulfate sodium (DSS) for induction of colitis. Some mice were exposed to psychological stress using a communication box. Body weight, colonic length, and histological inflammation were measured for assessment of colitis. Tumor necrosis factor (TNF)-α and IL-18 expression in the colon and IL-18 expression in the adrenal gland were analyzed using real-time PCR. The effect of anti-IL-18 antibody was also investigated. Effects of TNF-α and IL-18 on cytokine expressions were studied using the colonic epithelial cell line LS174T. Induction of psychological stress in DSS-treated wild-type mice significantly exacerbated colitis with enhanced expression of proinflammatory cytokines and IL-18. However, induction of psychological stress in DSS-treated IL-18(-/-) mice did not aggravate colitis compared with that in the IL-18(-/-) group given only DSS treatment. Stress-induced aggravation of colitis was ameliorated significantly by anti-IL-18 antibody treatment. IL-18 did not enhance TNF-α-induced expression of intercellular adhesion molecule-1 or IL-8 in LS174T. We established a model of colitis exacerbated by psychological stress. Psychological stress enhanced IL-18 expression and plays a proinflammatory role in stress-induced aggravation of colitis.

Mitochondrial density contributes to the immune response of macrophages to lipopolysaccharide via the MAPK pathway.

We investigated the role of mitochondrial reactive oxygen species (ROS) in the response of macrophages to lipopolysaccharide (LPS) using RAW 264.7 cells and their ρ(o) cells lacking mitochondria. Mitochondrial density, respiratory activity and related proteins in ρ(o) cells were significantly lower than those in RAW cells. LPS rapidly stimulated mitochondrial ROS prior to cytokine secretion, such as TNF-α and IL-6, from RAW 264.7 cells by activating the MAPK pathway, while the response was attenuated in ρ(o) cells. Exposure of ρ(o) cells to H(2)O(2) partially restored the secretion of cytokines induced by LPS. These results suggest that mitochondrial density and/or the respiratory state contribute to intracellular oxidative stress, which is responsible for the stimulation of LPS-induced MAPK signaling to enhance cytokine release from macrophages.

Dynamic aspects of ascorbic acid metabolism in the circulation: analysis by ascorbate oxidase with a prolonged in vivo half-life.

Because AA (L-ascorbic acid) scavenges various types of free radicals to form MDAA (monodehydroascorbic acid) and DAA (dehydroascorbic acid), its regeneration from the oxidized metabolites is critically important for humans and other animals that lack the ability to synthesize this antioxidant. To study the dynamic aspects of AA metabolism in the circulation, a long acting AOase (ascorbate oxidase) derivative was synthesized by covalently linking PEG [poly(ethylene glycol)] to the enzyme. Fairly low concentrations of the modified enzyme (PEG-AOase) rapidly decreased AA levels in isolated fresh plasma and blood samples with a concomitant increase in their levels of MDAA and DAA. In contrast, relatively high doses of PEG-AOase were required to decrease the circulating plasma AA levels of both normal rats and ODS (osteogenic disorder Shionogi) rats that lack the ability to synthesize AA. Administration of 50 units of PEG-AOase/kg of body weight rapidly decreased AA levels in plasma and the kidney without affecting the levels in other tissues, such as the liver, brain, lung, adrenal grand and skeletal muscles. PEG-AOase slightly, but significantly, decreased glutathione (GSH) levels in the liver without affecting those in other tissues. Suppression of hepatic synthesis of GSH by administration of BSO [L-buthionin-(S,R)-sulfoximine] enhanced the PEG-AOase-induced decrease in plasma AA levels. These and other results suggest that the circulating AA is reductively regenerated from MDAA extremely rapidly and that hepatic GSH plays important roles in the regeneration of this antioxidant.

Interleukin-18 prevents apoptosis via PI3K/Akt pathway in normal human keratinocytes.

Interleukin-18 (IL-18) is a pleiotropic cytokine expressed in both immune and non-immune cells. In the present study, we demonstrate an anti-apoptotic role of IL-18 in normal human neonatal foreskin epidermal keratinocytes (NHEK-F). Cultured NHEK-F spontaneously produced the active form of IL-18. Treatment of NHEK-F cells with anti-IL-18 receptor alpha-chain neutralizing antibody increased apoptosis and caspase-3 activity. Exogenous IL-18 augmented phosphorylation of Akt and activation of NF-kappaB. The promotion of Akt phosphorylation by IL-18 was abolished by LY294002, a PI3K inhibitor, but not SN50, an NF-kappaB inhibitor, indicating that IL-18 functions via the PI3K/Akt pathway and independently of NF-kappaB. In addition, IL-18 was found to augment expression of anti-apoptotic proteins, Bcl-2, XIAP and glucose regulated protein78/BiP, while anti-IL-18 receptor alpha-chain neutralizing antibody suppressed expression of Bcl-2, XIAP, glucose regulated protein94 and protein disulfide isomerase. Taken together, these results indicate that IL-18 plays an important role in keratinocyte survival.

Juzen-taiho-to, an herbal medicine, activates and enhances phagocytosis in microglia/macrophages.

Microglia are the main resident immunocompetent and phagocytic cells in the central nervous system (CNS). Activated microglia could play phagocytic roles as well as mediate inflammatory processes in the CNS. Involvement of activated microglia in the pathogenesis has been demonstrated in several neurological diseases including Alzheimer's disease (AD). Juzen-taiho-to (JTT), a traditional herbal medicine, has been reported to have effects on activating immune responses and phagocytosis. So far, little is known about the effects of this Kampo formulation JTT on microglia and in AD. In this report, we studied the effects of JTT on the activation and phagocytic functions of mouse microglia and bone marrow-derived macrophages (BMM). JTT could activate microglia, which was confirmed by the prominent morphological change and increased surface expression of an activation marker CD11b. In addition, JTT was revealed to induce microglial proliferation, and enhance microglial phagocytosis of, without eliciting an excessive production of nitric oxide. Furthermore, when mice were administrated with JTT in vivo, their BMM showed more effective phagocytosis of fibrillar Abeta(1-42). These findings implicate the therapeutic potential of JTT in AD and other neurological diseases accompanied by microglial activation.

Physical exercise-associated gene expression signatures in peripheral blood.

OBJECTIVE: To assess response to physical stress, gene expression profiles in peripheral blood cells were analyzed using an original microarray carrying 1467 stress-responsive complementary DNA probes. DESIGN: Gene expression was analyzed at 4, 24, and 48 hours after exercising on a cycle ergometer at 60% VO2 max for 1 hour (aerobic exercise) or until exhausted (exhaustive exercise). SETTING: Institute of Health Biosciences, University of Tokushima Graduate School. PARTICIPANTS: Twelve healthy male students of the postgraduate or undergraduate school. INTERVENTIONS: The volunteers performed the aerobic or exhaustive exercise on a cycle ergometer. MAIN OUTCOME MEASUREMENTS: Detection of aerobic exercise-responsive or exhaustive exercise-responsive genes in peripheral blood cells. RESULTS: Aerobic and exhaustive exercise transiently changed the expression of 21 and 16 genes, respectively, with the peak at 4 hours. Only 2 genes significantly responded to both types of exercise. Exhaustive but not aerobic exercise produced a secondary response with significantly altered expression of 14 genes at 24 hours. Five of those genes encode receptors for neurotransmitters (HTR1A, CHRNB2, GABRB3, GABRG3, and LOC51289). CONCLUSIONS: The behavior of the individual genes shown here may be informative to objectively assess acute physical stress and exhaustion-associated responses.

Protection of CD8+ T cells from activation-induced cell death by IL-18.

Role of IL-18 on proliferation and survival of CD8+ T cells, activated by immobilized anti-CD3 antibody (anti-CD3), was examined. Proliferation and survival of activated T cells, especially that of CD8+ T cells, were impaired by IL-18 deficiency [IL-18 knockout (KO)]. After 3 days of culture with anti-CD3, the number of living CD8+ T cells from IL-18KO mice was approximately 25% of that from wild-type (WT) mice but was increased to the same level as WT cells by the addition of IL-18. The expression of IL-18 receptors (IL-18Rs), particularly IL-18Rbeta chain, in naïve CD8+ T cells was very low but elevated after stimulation with anti-CD3. Blockade of IL-18R by anti-IL-18R antibody on activated WT CD8+ T cells resulted in reduction of living cells, suggesting that IL-18 promotes survival of proliferating CD8+ T cells. Levels of Bcl-2 in activated IL-18KO CD8+ T cells were lower than those in WT cells but were raised by exogenous IL-18. Blockade of IL-18R on WT CD8+ T cells decreased the expression of surface markers CD122 and CD94, which are related to cell viability, and the expression of these markers was increased by exogenous IL-18 in IL-18KO cells. These results suggest that IL-18 acts directly on activated CD8+ T cells through IL-18Rs and promotes their survival to expand the population.

NADPH oxidases in the gastrointestinal tract: a potential role of Nox1 in innate immune response and carcinogenesis.

The gastrointestinal epithelium functions as physical and innate immune barriers against commensal or pathogenic microbes. NADPH oxidase 1 (Nox1) and dual oxidase 2 (Duox2), highly expressed in the colon, are suggested to play a potential role in host defense. Guinea-pig gastric pit cells and human colonic epithelial cells (T84 cells) express Nox1. With regard to activation of Nox1, the gastric epithelial cells are primed with Helicobacter pylori lipopolysaccharide, whereas T84 cells preferentially use the Toll-like receptor (TLR) 5, rather than TLR4, against Salmonella enteritidis infection. Thus, gastric and colonic epithelial cells may use different TLR members to discern pathogenicities among bacteria, depending on their environments and to activate Nox1 appropriately for host defense. Nox1-derived reactive oxygen species (ROS) have been implicated in the pathogenesis of inflammation-associated tumor development. The human stomach does not express Nox1. Helicobacter pylori infection alone does not induce it, whereas Nox1 is specifically expressed in gastric adenocarcinomas. In the human colon, Nox1 is differentiation-dependently expressed, and its expression is upregulated in adenomas and well-differentiated adenocarcinomas. Although Nox1 expression may not be directly linked to mitogenic activity, Nox1-derived ROS may exert a cancer-promoting effect by increasing resistance to programmed cell death of tumor cells.

Production of IL-13 in spleen cells by IL-18 and IL-12 through generation of NK-like cells.

Treatment of Nylon wool-passed cells (NWC) prepared from the spleen of C57BL/6 mice with IL-18 and IL-12, but not with IL-18 alone, resulted in induction of IFN-gamma, a Th1 cytokine, and GM-CSF at 24 h, and IL-13, a Th2 cytokine at 72 h. The induction of IL-13 was suppressed by anti-GM-CSF antibody, indicating involvement of GM-CSF in IL-13 production. When NWC incubated with IL-18 and IL-12 for 72 h ("primary treatment") were treated again with the same cytokines ("secondary treatment"), IL-13 was induced much more quickly than observed in the primary treatment. Flow cytometric analysis of NWC after the primary treatment showed marked increases in the CD4(-)CD8(-) non-T cell population bearing CD25(+), CD45RB(super high) and CD122(+). These cells were positive for CD49b but negative for NK1.1, indicating that they were not typical but NK-like cells. The NK-like cells produced IL-13 in response to the treatment with IL-18 alone, indicating that the generation of these cells in the primary treatment likely accounts for the quick production of IL-13 in the secondary treatment. These results show that IL-18 and IL-12 generates the NK-like cells in NWC by a process mediated by GM-CSF that are ready for producing IL-13.

A role of the adrenal gland in stress-induced up-regulation of cytokines in plasma.

To reveal a pathway by which psychological/physical stresses influence host defense capability, responses to immobilization stress in mice were investigated, focusing on a multifunctional cytokine, interleukin-18 (IL-18). Immobilization stress induced interleukin-18 accumulation in plasma and in the adrenal gland. Inhibition on ACTH resulted in suppressed levels of IL-18 both in plasma and the adrenal gland. In hemi-adrenalectomized mice, plasma IL-18 levels after stress were lower than in sham-operated mice. This, together with the observation in stressed hemi-adrenalectomized mice that IL-6 levels in plasma were suppressed but up-regulated by recombinant IL-18, showed that the adrenal gland plays a crucial role in stress-related elevation of IL-6 in plasma via IL-18. Adrenal gland is highlighted as an organ connecting the psychological, endocrine, and immune systems. Controlling the secretion of IL-18 from the adrenal gland may serve as a possible preventative means against a stress-related disruption of host defenses.