Evaluation of immunotoxic and immunodisruptive effects of inorganic arsenite on human monocytes/macrophages

A trivalent inorganic arsenic, arsenite, has been causing chronic inflammation in humans through the consumption of contaminated well water. The total peripheral blood arsenic concentrations of chronic arsenic-exposed patients, who had inflammatory-like immune responses, are less than 1 microM, thus, nM concentrations may be very important regarding the chronic inflammatory effects by arsenite. However, there are few reports about the biological effects of low concentrations of arsenite in mammalian cells, especially in normal immune effector cells. In this study, we examined whether arsenite has any biological and/or toxicological effects on the differentiation of human peripheral blood monocytes into macrophages using the colony-stimulating factor (CSF) in vitro compared with that of other metallic compounds, and found that arsenite sensitively inhibited the CSF-induced in vitro maturation of monocytes into macrophages at nM levels, and it also induced small, nonadhesive and CD14-positive abnormal macrophage generation from monocytes with granulocyte-macrophage CSF (GM-CSF) at 50-500 nM without cell death. The addition of other metallic compounds, including chromium, selenium, mercury, cadmium, nickel, copper, zinc, cobalt, manganese and other human pentavalent arsenic metabolites, such as inorganic arsenate, monomethylarsonic acid and dimethylarsinic acid, could not induce the same abnormal cell generation from monocytes with CSFs at any concentration and any additional time schedules; they showed only simple cytolethality in monocytes and macrophages at n-mM levels accompanied by cell death. This work may have implications in the arsenic-induced chronic inflammation in humans.     

Association of the Neprilysin gene with susceptibility to late-onset Alzheimer's disease

Neprilysin (NEP), also known as neutral endopeptidase, enkephalinase, CD 10, and common acute lymphoblastic leukemia antigen, is a 97-kD protein. NEP can degrade amyloid beta peptides, and its mRNA and protein levels are known to be reduced in the brains of patients with Alzheimer's disease (AD), making the NEP gene a substantial candidate for an AD risk factor. We examined the genetic association of three NEP polymorphisms, a GT-repeat polymorphism and two single nucleotide polymorphisms (SNPs, -1075A>G and -1284G>C) in its promoter region, with AD in a Japanese case-control sample (240 patients and 163 controls). The GT-repeat polymorphism, but not the SNPs, was significantly associated with late-onset AD (p = 0.0007). Our findings suggest that the GT-repeat polymorphism in the promoter region of the NEP gene or some other unknown polymorphisms, which are in a linkage disequilibrium, confer a susceptibility to late-onset AD.     

Induction of cellular immunity to varicella-zoster virus glycoproteins tested with pernasal coadministration of Escherichia coli enterotoxin in mice

A mutant of Escherichia coli enterotoxin promotes the induction of cellular immunity to a live varicella vaccine (the Oka strain) as a mucosal adjuvant in mice. An investigation was carried out to determine which of the purified glycoproteins of the virus among three induced cellular immunity with a single nasal administration. Spleen cells from mice immunized nasally with the vaccine and toxin produced interleukin-2 (IL-2) at the same level on restimulation in vitro with glycoprotein H: glycoprotein L (gH:gL), gB, and gE:gI, but not IL-4. The spleen cells from mice immunized with gH:gL, gB, or gE:gI and toxin produced IL-2 on restimulation with gH:gL, gB, or gE:gI, respectively, and the vaccine, but not IL-4. Immunization with gH:gL and the toxin showed increased thymidine uptake and production of IL-2 and interferon-gamma (IFN-gamma) of the spleen cells, but not IL-4, depending on the dose of gH:gL used for immunization and restimulation in vitro. Purified gE:gI and gB have been reported to be the strongest stimulators of cellular immunity to varicella upon subcutaneous injection and are useful as a subunit vaccine. All the glycoproteins tested are excellent stimulators of cellular immunity to the virus and itself on nasal co-immunization with the toxin.     

Familial inclusion body myositis: a report on two Japanese sisters

Familial occurrence of inclusion body myositis is extremely rare, and only a few cases in Western countries have been reported. In these reports, a strong association of this disease with DR3 (DRB1*0301/0302) and the efficacy of immunosuppressants suggested that an immune pathomechanism is involved in the disease. We, for the first time, report two Japanese sisters who suffered myopathy clinicopathologically similar to inclusion body myositis. One sister received corticosteroid and azathioprine and the therapy relieved dysphagia. Both of our patients had DR15(2)/4 (DRB1*1502/0405), suggesting a distinct genetic association with the disease in the Japanese population.     

Three cases of gastrointestinal stromal tumor (GIST) with bone metastasis]

We report three cases of gastrointestinal stromal tumor (GIST) with delayed bone metastasis at least four years after initial surgery. One small intestinal and two rectal GISTs were all considered as high-risk according to the classification based on tumor size and mitotic count. GIST usually metastasizes to the liver and peritoneum, however bone metastasis should be considered in the patients with long prognosis.     

Variance in effects of subthalamic nucleus stimulation]

Chronic stimulation of subthalamus nucleus (STN) is effective in treating severe motor fluctuation and levodopa induced dyskinesia as well as parkinsonian motor symptoms. The improvement of peak-dose/diphasic dyskinesias of STN stimulation is considered to be due to the decrease in the daily dosage of antiparkinsonian drugs. However one report pointed out that STN stimulation improved directly levodopa induced dyskinesia. Moreover the timing of the improvement for levodopa induced dyskinesia is not yet obvious. In the present study, we have assessed variance in the latency of improvement of levodopa induced dyskinesia due to STN stimulation. In addition, we would clarify an issue which cite of STN stimulation improved parkinsonian symptoms and motor complication (motor dyskinesias and motor fluctuation). We have studied seven patients diagnosed with advanced idiopathic Parkinson's disease with motor fluctuations and levodopa induced dyskinesias. Before and after the implantation of stimulating electrode, patients were assessed by the Unified Parkinson's Disease Rating Scale and % 'OFF' motor state. The dosage of the antiparkinsonian medication was not modified for one month prior to implantation. Following implantation, dosage of the medication and strength of stimulation was adjusted, if necessary. Symptoms of motor fluctuation and dyskinesia improved in all patients six month after surgery. The mean off-time duration and dyskinesia disability improved compared with presurgical conditions. However, the time course of the improvement of dyskinesias was not the same among patients. Contralateral limb dyskinesias in three patients improved immediately after the stimulation without modification of medication. In contrast, the stimulation worsened contralateral limb dyskinesias in other three patients immediately following the surgery. In two of the three patients, dyskinesias gradually improved within one month after surgery without reducing the dosage of medication. Dyskinesias of the other patient improved following a reduction in the dosage of medication one month after the surgery. Improvement of parkinsonian symptoms of the patients with longer latency of stimulation effect for dyskinesias was better than that of the patients with shorter latency. Stimulation cite of the former group appeared to locate more central than that of the latter group. Latency and strength of the effects of STN stimulation are variable.     

Augmentation of lipopolysaccharide-induced nitric oxide production by alpha-galactosylceramide in mouse peritoneal cells

The effect of alpha-galactosylceramide (alpha-GalCer) on lipopolysaccharide (LPS)-induced nitric oxide (NO) production in mouse peritoneal cells was studied. alpha-GalCer augmented LPS-induced NO production in mouse peritoneal cells, but not in RAW 264.7 macrophage cells. alpha-GalCer augmented NO production, but not tumor necrosis factor (TNF)-alpha production in LPS-stimulated peritoneal cells. Peritoneal cells produced a significant level of interferon (IFN)-gamma in response to alpha-GalCer and anti-IFN-gamma antibody abolished the augmentation of LPS-induced NO production by alpha-GalCer. Moreover, anti-IFN-gamma antibody prevented the enhanced expression of an inducible type of NO synthase mRNA by alpha-GalCer. alpha-GalCer did not augment LPS-induced NO production in peritoneal cells from natural killer T (NKT)-deficient mice. Therefore, it was suggested that alpha-GalCer might augment LPS-induced NO production in peritoneal cells through release of IFN-gamma from NKT cells.     

Differences in the mechanism of nitric oxide production between mouse vascular endothelial cells and macrophages

The detailed mechanism of NO production in mouse vascular endothelial cells, END-D, was studied. The NO production in END-D cells was triggered by gamma interferon (IFN-gamma), but not LPS. However, LPS augmented the NO production in IFN-gamma-stimulated END-D cells. A high level of NO production was due to the expression of an inducible type of NO synthase (iNOS) in those cells. A significant amount of NO was detected 18 h after IFN-gamma stimulation, accompanied by the delayed iNOS expression. The JAK/STAT signal pathway mediated IFN-gamma-induced NO production, but did not participate in the LPS-induced augmentation. Further, no activation of nuclear factor (NF)-kappaB was involved in the NO production in END-D cells stimulated with either IFN-gamma and/or LPS. The mechanism of NO production in END-D cells was suggested to be different from that in mouse macrophages. The differential regulation of NO production in mouse vascular endothelial cells and macrophages is discussed.     

C2-ceramide inhibits LPS-induced nitric oxide production in RAW 264.7 macrophage cells through down-regulating the activation of Akt

The effect of C(2)-ceramide, a membrane-permeable ceramide analogue, on nitric oxide (NO) production in lipopolysaccharide (LPS)-stimulated RAW 264.7 cells was studied. The non-toxic concentration of C(2)-ceramide inhibited LPS-induced NO production. It was due to the attenuated expression of the inducible type of NO synthase (iNOS). C(2)-ceramide did not influence the phosphorylation of a series of mitogen-activated protein (MAP) kinases in response to LPS. On the other hand, C(2)-ceramide down-regulated the phosphorylation of Akt in LPS-stimulated RAW 264.7 cells, followed by the impairment of nuclear factor (NF)-kappaB activation. Moreover, the Akt dominant-negative mutant inhibited LPS-induced NO production. C(2)-ceramide was suggested to inhibit LPS-induced NO production through down-regulating the activation of Akt.