Alpha-GalCer ameliorates listeriosis by accelerating infiltration of Gr-1+ cells into the liver

Alpha-galactosylceramide (alpha-GalCer) activates invariant (i)NKT cells, which in turn stimulate immunocompetent cells. Although activation of iNKT cells appears critical for regulation of immune responses, it remains elusive whether protection against intracellular bacteria can be induced by alpha-GalCer. Here, we show that alpha-GalCer treatment ameliorates murine listeriosis, and inhibits inflammation following Listeria monocytogenes infection. Liver infiltration of Gr-1+ cells and gamma/delta T cells was accelerated by alpha-GalCer treatment. Gr-1+ cell and gamma/delta T-cell depletion exacerbated listeriosis in alpha-GalCer-treated mice, and this effect was more pronounced after depletion of Gr-1+ cells than that of gamma/delta T cells. Although GM-CSF and IL-17 were secreted by NKT cells after alpha-GalCer treatment, liver infiltration of Gr-1+ cells was not prevented by neutralizing mAb. In parallel to the numerical increase of CD11b+Gr-1+ cells in the liver following alpha-GalCer treatment, CD11b-Gr-1+ cells were numerically reduced in the bone marrow. In addition, respiratory burst in Gr-1+ cells was enhanced by alpha-GalCer treatment. Our results indicate that alpha-GalCer-induced antibacterial immunity is caused, in part, by accelerated infiltration of Gr-1+ cells and to a lesser degree of gamma/delta T cells into the liver. We also suggest that the infiltration of Gr-1+ cells is caused by an accelerated supply from the bone marrow.

Alpha-galactosylceramide promotes killing of Listeria monocytogenes within the macrophage phagosome through invariant NKT-cell activation

alpha-Galactosylceramide (alpha-GalCer) has been exploited for the treatment of microbial infections. Although amelioration of infection by alpha-GalCer involves invariant natural killer T (iNKT)-cell activation, it remains to be determined whether macrophages (Mphi) participate in the control of microbial pathogens. In the present study, we examined the participation of Mphi in immune intervention in infection by alpha-GalCer using a murine model of listeriosis. Phagocytic and bactericidal activities of peritoneal Mphi from C57BL/6 mice, but not iNKT cell-deficient mice, were enhanced after intraperitoneal injection of alpha-GalCer despite the absence of iNKT cells in the peritoneal cavity. High levels of gamma interferon (IFN-gamma) and nitric oxide (NO) were detected in the peritoneal cavities of mice treated with alpha-GalCer and in culture supernatants of peritoneal Mphi from mice treated with alpha-GalCer, respectively. Although enhanced bactericidal activity of peritoneal Mphi by alpha-GalCer was abrogated by endogenous IFN-gamma neutralization, this was only marginally affected by NO inhibition. Similar results were obtained by using a listeriolysin O-deficient strain of Listeria monocytogenes. Moreover, respiratory burst in Mphi was increased after alpha-GalCer treatment. Our results suggest that amelioration of listeriosis by alpha-GalCer is, in part, caused by enhanced killing of L. monocytogenes within phagosomes of Mphi activated by IFN-gamma from iNKT cells residing in an organ(s) other than the peritoneal cavity.

Dissociated expression of natural killer 1.1 and T-cell receptor by invariant natural killer T cells after interleukin-12 receptor and T-cell receptor signalling

Invariant (i) natural killer T (NKT) cells become undetectable after stimulation with alpha-galactosylceramide (alpha-GalCer) or interleukin (IL)-12. Although down-modulation of surface T-cell receptor (TCR)/NKR-P1C (NK1.1) expression has been shown convincingly after stimulation with alpha-GalCer, it is unclear whether this also holds true for IL-12 stimulation. To determine whether failure to detect iNKT cells after IL-12 stimulation is caused by dissociation/internalization of TCR and/or NKR-P1C, or by block of de novo synthesis of these molecules, and to examine the role of IL-12 in the disappearance of iNKT cells after stimulation with alpha-GalCer, surface (s)/cytoplasmic (c) protein expression, as well as messenger RNA (mRNA) expression of TCR/NKR-P1C by iNKT cells after stimulation with alpha-GalCer or IL-12, and the influence of IL-12 neutralization on the down-modulation of sTCR/sNKR-P1C expression by iNKT cells after stimulation with alpha-GalCer were examined. The s/cTCR(+ )s/cNKR-P1C(+) iNKT cells became undetectable after in vivo administration of alpha-GalCer, which was partially prevented by IL-12 neutralization. Whereas s/cNKR-P1C(+) iNKT cells became undetectable after in vivo administration of IL-12, s/cTCR(+) iNKT cells were only marginally affected. mRNA expression of TCR/NKR-P1C remained unaffected by alpha-GalCer or IL-12 treatment, despite the down-modulation of cTCR and/or cNKR-P1C protein expression. By contrast, cTCR(+ )cNKR-P1C(+) sTCR(-) sNKR-P1C(-) iNKT cells and cNKR-P1C(+) sNKR-P1C(-) iNKT cells were detectable after in vitro stimulation with alpha-GalCer and IL-12, respectively. Our results indicate that TCR and NKR-P1C expression by iNKT cells is differentially regulated by signalling through TCR and IL-12R. They also suggest that IL-12 participates, in part, in the disappearance of iNKT cells after stimulation with alpha-GalCer by down-modulating not only sNKR-P1C, but also sTCR.

Intracellular bacterial infection and invariant NKT cells

The invariant (i) natural killer (NK)T cells represent a unique subset of T lymphocytes which express the V alpha 14 chain of the T cell receptor (TCR), that recognizes glycolipid antigens presented by the nonpolymorphic major histocompatibility complex (MHC) class I-like antigen presentation molecule CD1d, and they participate in protection against some microbial pathogens. Although iNKT cells have originally been regarded as T cells co-expressing NKR-P1B/C (NK1.1: CD 161), they do not seem to consistently express this marker, since NK1.1 surface expression on iNKT cells undergoes dramatic changes following facultative intracellular bacterial infection, which is correlated with functional changes of this cell population. Accumulating evidence suggests that NK1.1 allows recognition of "missing-self", thus controlling activation/inhibition of NK1.1-expressing cells. Therefore, it is tempting to suggest that iNKT cells participate in the regulation of host immune responses during facultative intracellular bacterial infection by controlling NK1.1 surface expression. These findings shed light not only on the unique role of iNKT cells in microbial infection, but also provide evidence for new aspects of the NK1.1 as a regulatory molecule on these cells.

Liver invariant NKT cells and listeriosis

The invariant (i) NKT cells represent unique T lymphocytes expressing TCRValpha14. Although iNKT cells have been regarded as T lymphocytes expressing NK1.1, they do not consistently express this marker. NK1.1 allows recognition of "missing-self" and thus controls inhibition/activation of iNKT cells. It is thus tempting to assume that iNKT cells participate in the regulation of host immune responses during microbial infection by controlling NK1.1 expression. These findings shed light on the unique role of iNKT cells in microbial infection and provide an evidence for unique aspects of the NK1.1 on these cells as a regulatory molecule.

Non-oxidative glucose disposal is reduced in type 2 diabetes, but can be restored by aerobic exercise

Whole-body glucose utilization consists of mitochondrial glucose oxidation and non-oxidative glycogen synthesis. We examined whether reduction of both non-oxidative glucose disposal and glucose oxidation contributes to insulin resistance in type 2 diabetes. We also examined the effects of exercise on these two components. Whole-body glucose disposal rate (GDR, mg/kg/min) was evaluated in 37 type 2 diabetic (T2DM) and 17 non-diabetic (non-DM) subjects as the mean of glucose infusion rate during steady state in the euglycaemic-hyperinsulinaemic clamp study. Glucose oxidation rates were assessed by indirect calorimetry, and non-oxidative GDR was calculated by subtracting glucose oxidation rate from GDR. Intramyocellular lipid (IMCL) content of the soleus muscle was measured using (1)H-magnetic resonance spectroscopy. In 10 T2DM subjects, the changes in oxidative and non-oxidative glucose disposal during clamp were examined after 3-month exercise intervention. GDR (2.93 +/- 1.55 vs. 4.55 +/- 1.83, p = 0.001) and non-oxidative GDR (1.45 +/- 1.52 vs. 3.01 +/- 1.87, p = 0.002) were significantly lower in T2DM than in non-DM subjects. Glucose oxidation rate was comparable in the two groups, and inversely correlated with IMCL (n = 15, r =-0.565, p = 0.028). GDR (2.28 +/- 1.67 to 4.63 +/- 2.42, p = 0.021) and non-oxidative GDR (0.72 +/- 1.27 to 2.26 +/- 1.91, p = 0.047) were increased after exercise intervention, although the change in glucose oxidation rate was not significant. In summary, reduction of non-oxidative glucose disposal may contribute to decreased whole-body glucose utilization. In addition, exercise improves insulin resistance mainly by increasing non-oxidative glucose disposal in type 2 diabetes.

New Similarity Measure Between Two Fuzzy Sets

We propose a new similarity measure between two fuzzy sets based on their relative sigma count and extend it to define two other measures, one a similarity measure between elements in fuzzy sets and the second a similarity measure between fuzzy sets in which all elements in the universe of discourse are weighted. We compare our proposal to several previous measures proposed in [1-6].

Toward a Generalization of Rough Sets Based on Active and Passive Relations

In the generalization of rough sets, many concepts use a relation weaker than the equivalence relation usually used in classical rough sets, e.g., induced by a conditional probability relation. The conditional probability relation is binary and assumes that the relationship between two data (elements or objects) resembles a relationship between two events in conditional probability. We use the asymmetric property of the conditional probability relation to propose active and passive relations, then discuss a generalization and properties of rough sets based on active and passive relations.

Rapid development of a gamma interferon-secreting glycolipid/CD1d-specific Valpha14+ NK1.1- T-cell subset after bacterial infection

The phenotypic and functional changes of glycolipid presented by CD1d(glycolipid/CD1d) specific Valpha14+ T cells in the liver of mice at early stages of bacterial infection were investigated. After Listeria monocytogenes infection or interleukin-12 (IL-12) treatment, alpha-galactosylceramide/CD1d tetramer-reactive (alpha-GalCer/CD1d+) T cells coexpressing natural killer (NK) 1.1 marker became undetectable and, concomitantly, cells lacking NK1.1 emerged in both euthymic and thymectomized animals. Depletion of the NK1.1+ subpopulation prevented the emergence of alpha-GalCer/CD1d+ NK1.1- T cells. Before infection, NK1.1+, rather than NK1.1-, alpha-GalCer/CD1d+ T cells coexpressing CD4 were responsible for IL-4 production, whereas gamma interferon (IFN-gamma) was produced by cells regardless of NK1.1 or CD4 expression. After infection, IL-4-secreting cells became undetectable among alpha-GalCer/CD1d+ T cells, but considerable numbers of IFN-gamma-secreting cells were found among NK1.1-, but not NK1.1+, cells lacking CD4. Thus, NK1.1 surface expression and functional activities of Valpha14+ T cells underwent dramatic changes at early stages of listeriosis, and these alterations progressed in a thymus-independent manner. In mutant mice lacking all alpha-GalCer/CD1d+ T cells listeriosis was ameliorated, suggesting that the subtle contribution of the NK1.1- T-cell subset to antibacterial protection is covered by more profound detrimental effects of the NK1.1+ T-cell subset.

Striptease on glass: validation of an improved stripping procedure for in situ microarrays

Microarrays have rapidly become an indispensable tool for gene analysis. Microarray experiments can be cost prohibitive, however, largely due to the price of the arrays themselves. Whilst different methods for stripping filter arrays on membranes have been established, only very few protocols are published for thermal and chemical stripping of microarrays on glass. Most of these protocols for stripping microarrays on glass were developed in combination with specific surface chemistry and different coatings for covalently immobilizing presynthesized DNA in a deposition process. We have developed a method for stripping commercial in situ microarrays using a multi-step procedure. We present a method that uses mild chemical degradation complemented by enzymatic treatment. We took advantage of the differences in biochemical properties of covalently linked DNA oligonucleotides on in situ synthesized microarrays and the antisense cRNA hybridization probes. The success of stripping protocols for microarrays on glass was critically dependent on the type of arrays, the nature of sample used for hybridization, as well as hybridization and washing conditions. The protocol employs alkali hydrolysis of the cRNA, several enzymatic degradation steps using RNAses and Proteinase K, combined with appropriate washing steps. Stripped arrays were rehybridized using the same protocols as for new microarrays. The stripping method was validated with microarrays from different suppliers and rehybridization of stripped in situ arrays yielded comparable results to hybridizations done on unused, new arrays with no significant loss in precision or accuracy. We show that stripping of commercial in situ arrays is feasible and that reuse of stripped arrays gave similar results compared to unused ones. This was true even for biological samples that show only slight differences in their expression profiles. Our analyses indicate that the stripping procedure does not significantly influence data quality derived from post-primary hybridizations. The method is robust, easy to perform, inexpensive, and results after reuse are of comparable accuracy to new arrays.

Body fat mass and lean mass as predictors of survival in hemodialysis patients

A higher body mass index (BMI) is a predictor of better survival in hemodialysis patients, although the relative importance of body fat and lean mass has not been examined in the dialysis population. We performed an observational cohort study in 808 patients with end-stage renal disease on maintenance hemodialysis. At baseline, fat mass was measured by dual-energy X-ray absorptiometry and expressed as fat mass index (FMI; kg/m2). Lean mass index (LMI) was defined as BMI minus FMI. During the mean follow-up period of 53 months, 147 deaths, including 62 cardiovascular (CV) and 85 non-CV fatal events, were recorded. In univariate analysis, LMI was not significantly associated with CV or non-CV death, whereas a higher FMI was predictive of lower risk for non-CV death. Analyses with multivariate Cox models, which took other confounding variables as covariates, indicated the independent associations between a higher LMI and a lower risk of CV death, as well as between a higher FMI and a lower risk of non-CV death. These results indicate that increased fat mass and lean mass were both conditions associated with better outcomes in the dialysis population.