Immunosuppressive dietary n-3 polyunsaturated fatty acids differentially modulate costimulatory regulation of murine CD4+ T-cell function

Consumption of fish oils (FO) enriched with the n-3 polyunsaturated fatty acids (PUFA), docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), is beneficial to a variety of inflammatory disorders due, in part, to the alteration of membrane composition of T-lymphocytes and other immune cells. We previously observed that down-regulation of proliferation and cytokine synthesis by CD4+ T-cells in mice fed diets rich in n-3 PUFA was dependent on the involvement of CD28, a co-stimulatory molecule necessary for T-cell activation. Since the co-receptor homologues, CD28 and CTLA-4, have opposing effects on T-cell activation, we hypothesized that the balance of costimulatory and downregulatory properties of CD28 and CTLA-4, respectively, would be altered by diet. A significant increase (p<0.05) in CD28 and CTLA-4 surface expression was observed in CD4+ T-cells post-stimulation with phorbol ester and calcium ionophore (PMA/Iono) or anti-CD3 and anti-CD28 (&#945;CD3/CD28) antibodies in all diet groups. A significant increase (p<0.01; 20%) in the number of CD28 molecules was observed in n-3 PUFA vs. CO-fed mice after 48 h of in vitro CD4+ T-cell activation, and both CTLA-4 mRNA transcript and protein levels were upregulated by 50% at 72 h post-activation (p<0.01). Treatment with anti-CTLA-4 mAb in vivo in Mycobacterium bovis (BCG)-vaccinated mice did not alter the suppressive effects of dietary n-3 PUFA on antigen (PPD)-induced lymphocyte proliferation or delayed hypersensitivity reactions. T-cells from both the C57BL/6 and IL-10mice fed dietary n-3 PUFA after 72 h of in vitro stimulation with &#945;CD3/CD28. CD4T-cells from C57BL/6 mice fed DHA produced significantly less IFN&#947; and IL-10, while CD4T-cells from IL-10Ligation of CD28 upregulates IL-10 receptor (IL-10R) expression on CD4+ T-cells. Therefore, we hypothesized that dietary n-3 PUFA would suppress T-cell function through the effects of IL-10. Surprisingly, the proliferation of purified splenic CD4+ T-cells activated in vitro with &#945;CD3/CD28 was suppressed by dietary n-3 PUFA in both conventional mice (C57BL/6) and IL-10 gene knockout (IL-10(-/-)) mice. Furthermore, IL-10R cell surface expression was significantly down-regulated on CD4+ T-cells from both the C67BL/6 and IL-10(-/-) mice fed dietary n-3 PUFA produced significantly more IFN&#947; compared to the CO-fed group

Altered cellular infiltration and cytokine levels during early Mycobacterium tuberculosis sigC mutant infection are associated with late-stage disease attenuation and milder immunopathology in mice

<p>Abstract</p> <p>Background</p> <p>Mouse virulence assessments of certain <it>Mycobacterium tuberculosis </it>mutants have revealed an immunopathology defect in which high tissue CFU counts are observed but the tissue pathology and lethality are reduced. <it>M. tuberculosis </it>mutants which grow and persist in the mouse lungs, but have attenuated disease progression, have the immunopathology (<it>imp</it>) phenotype. The antigenic properties of these strains may alter the progression of disease due to a reduction in host immune cell recruitment to the lungs resulting in disease attenuation and prolonged host survival.</p> <p>Results</p> <p>In this study we focused on the mouse immune response to one such mutant; the <it>M. tuberculosis </it>Δ<it>sigC </it>mutant. Aerosol infection of DBA/2 and SCID mice with the <it>M. tuberculosis </it>Δ<it>sigC </it>mutant, complemented mutant and wild type strain showed proliferation of mutant bacilli in mouse lungs, but with decreased inflammation and mortality in DBA/2 mice. SCID mice shared the same phenotype as the DBA/2 mice in response to the Δ<it>sigC </it>mutant, however, they succumbed to the infection faster. Bronchoalveolar lavage (BAL) fluid analysis revealed elevated numbers of infiltrating neutrophils in the lungs of mice infected with wild type and complemented Δ<it>sigC </it>mutant strains but not in mice infected with the Δ<it>sigC </it>mutant. In addition, DBA/2 mice infected with the Δ<it>sigC </it>mutant had reduced levels of TNF-α, IL-1β, IL-6 and IFN-γ in the lungs. Similarly, there was a reduction in proinflammatory cytokines in the lungs of SCID mice. In contrast to the mouse model, the Δ<it>sigC </it>mutant had reduced initial growth in guinea pig lungs. A possible mechanism of attenuation in the Δ<it>sigC </it>mutant may be a reduction in neutrophilic-influx in the alveolar spaces of the lungs, and decreased proinflammatory cytokine secretion. In contrast to mouse data, the <it>M. tuberculosis </it>Δ<it>sigC </it>mutant proliferates slowly in guinea pig lungs, a setting characterized by caseating necrosis.</p> <p>Conclusion</p> <p>Our observations suggest that the immunopathology phenotype is associated with the inability to trigger a strong early immune response, resulting in disease attenuation. While macrophages and T cells have been shown to be important in containing <it>M. tuberculosis </it>disease our study has shown that neutrophils may also play an important role in the containment of this organism.</p

The Fabrication of Nano-Particles in Aqueous Solution From Oxyfluoride Glass Ceramics by Thermal Induction and Corrosion Treatment

An innovative route is reported to fabricate nano-particles in aqueous solution from oxyfluoride glass by the thermal induction and corrosion treatment in this letter. The investigations of X-ray diffraction and transmission electron microscope based on nano-particles in glass ceramics (GCs) and aqueous solution indicate that the nano-particles formed in glass matrix during the thermal induction process are released to aqueous solution and their structure, shape and luminescent properties in glass host can be kept. Owing to the designable composition of the nano-particles during glass preparation process, the method is a novel way to obtain nano-particles in aqueous solution from GCs

The Impact of Mouse Passaging of Mycobacterium tuberculosis Strains prior to Virulence Testing in the Mouse and Guinea Pig Aerosol Models

It has been hypothesized that the virulence of lab-passaged Mycobacterium tuberculosis and recombinant M. tuberculosis mutants might be reduced due to multiple in vitro passages, and that virulence might be augmented by passage of these strains through mice before quantitative virulence testing in the mouse or guinea pig aerosol models.By testing three M. tuberculosis H37Rv samples, one deletion mutant, and one recent clinical isolate for survival by the quantitative organ CFU counting method in mouse or guinea pig aerosol or intravenous infection models, we could discern no increase in bacterial fitness as a result of passaging of M. tuberculosis strains in mice prior to quantitative virulence testing in two animal models. Surface lipid expression as assessed by neutral red staining and thin-layer chromatography for PDIM analysis also failed to identify virulence correlates.These results indicate that animal passaging of M. tuberculosis strains prior to quantitative virulence testing in mouse or guinea pig models does not enhance or restore potency to strains that may have lost virulence due to in vitro passaging. It is critical to verify virulence of parental strains before genetic manipulations are undertaken and comparisons are made

Constitutive activation of glycogen synthase kinase-3β correlates with better prognosis and cyclin-dependent kinase inhibitors in human gastric cancer

Background: Aberrant regulation of glycogen synthase kinase-3 beta (GSK-3 beta) has been implicated in several human cancers; however, it has not been reported in the gastric cancer tissues to date. The present study was performed to determine the expression status of active form of GSK-3 beta phosphorylated at Tyr(216) (pGSK-3 beta) and its relationship with other tumor-associated proteins in human gastric cancers. Methods: Immunohistochemistry was performed on tissue array slides containing 281 human gastric carcinoma specimens. In addition, gastric cancer cells were cultured and treated with a GSK-3 beta inhibitor lithium chloride (LiCl) for immunoblot analysis. Results: We found that pGSK-3 beta was expressed in 129 (46%) of 281 cases examined, and was higher in the early-stages of pathologic tumor-node-metastasis (P < 0.001). The expression of pGSK-3 beta inversely correlated with lymphatic invasion (P < 0.001) and lymph node metastasis (P < 0.001) and correlated with a longer patient survival (P < 0.001). In addition, pGSK-3 beta expression positively correlated with that of p16, p21, p27, p53, APC, PTEN, MGMT, SMAD4, or KAl1 (P < 0.05), but not with that of cyclin D1. This was confirmed by immunoblot analysis using SNU-668 gastric cancer cells treated with LiCl. Conclusions: GSK-3 beta activation was frequently observed in early-stage gastric carcinoma and was significantly correlated with better prognosis. Thus, these findings suggest that GSK-3 beta activation is a useful prognostic marker for the early-stage gastric cancer.Hirakawa H, 2009, ONCOL REP, V22, P481, DOI 10.3892/or_00000460Dar AA, 2009, ONCOGENE, V28, P866, DOI 10.1038/onc.2008.434Holmes T, 2008, STEM CELLS, V26, P1288, DOI 10.1634/stemcells.2007-0600Wang Q, 2008, CELL DEATH DIFFER, V15, P908, DOI 10.1038/cdd.2008.2Takahashi-Yanaga F, 2008, CELL SIGNAL, V20, P581, DOI 10.1016/j.cellsig.2007.10.018Pan MH, 2007, J AGR FOOD CHEM, V55, P7777, DOI 10.1021/jf071520hShakoori A, 2007, CANCER SCI, V98, P1388, DOI 10.1111/j.1349-7006.2007.00545.xZheng HC, 2007, ANTICANCER RES, V27, P3561Saegusa M, 2007, J PATHOL, V213, P35, DOI 10.1002/path.2198Ma C, 2007, CANCER RES, V67, P7756, DOI 10.1158/0008-5472.CAN-06-4665Forde JE, 2007, CELL MOL LIFE SCI, V64, P1930, DOI 10.1007/s00018-007-7045-7Li YW, 2007, J BIOL CHEM, V282, P21542, DOI 10.1074/jbc.M701978200Ding QQ, 2007, CANCER RES, V67, P4564, DOI 10.1158/0008-5472.CAN-06-1788Kunnimalaiyaan M, 2007, MOL CANCER THER, V6, P1151, DOI 10.1158/1535-7163.MCT-06-0665Soto-Cerrato V, 2007, MOL CANCER THER, V6, P362, DOI 10.1158/1535-7163.MCT-06-0266Cao Q, 2006, CELL RES, V16, P671, DOI 10.1038/sj.cr.7310078Yang CH, 2006, PRECIS AGRIC, V7, P33, DOI 10.1007/s11119-005-6788-0Crew KD, 2006, WORLD J GASTROENTERO, V12, P354Mai W, 2007, ONCOLOGY-BASEL, V71, P297, DOI 10.1159/000106429Tan J, 2005, CANCER RES, V65, P9012, DOI 10.1158/0008-5472.CAN-05-1226Shakoori A, 2005, BIOCHEM BIOPH RES CO, V334, P1365, DOI 10.1016/j.bbrc.2005.07.041Farago M, 2005, CANCER RES, V65, P5792Ghosh JC, 2005, CLIN CANCER RES, V11, P4580Liao XB, 2003, MOL CANCER THER, V2, P1215Lee HS, 2003, J PATHOL, V200, P39, DOI 10.1002/path.1288Doble BW, 2003, J CELL SCI, V116, P1175, DOI 10.1242/jcs.00384Gotoh J, 2003, CARCINOGENESIS, V24, P435Goto H, 2002, ORAL ONCOL, V38, P549Lee HS, 2001, INT J CANCER, V91, P619D`Amico M, 2000, J BIOL CHEM, V275, P32649, DOI 10.1074/jbc.M000643200Endoh Y, 2000, J PATHOL, V191, P257Wu LY, 1998, J NATL MED ASSOC, V90, P410WOODGETT JR, 1984, BIOCHIM BIOPHYS ACTA, V788, P339

Incorporation of a Dietary Omega 3 Fatty Acid Impairs Murine Macrophage Responses to Mycobacterium tuberculosis

by creating an immunosuppressive environment. We hypothesized that incorporation of n-3 PUFA suppresses activation of macrophage antimycobacterial responses and favors bacterial growth, in part, by modulating the IFNγ-mediated signaling pathway.. The fatty acid composition of macrophage membranes was modified significantly by DHA treatment. DHA-treated macrophages were less effective in controlling intracellular mycobacteria and showed impaired oxidative metabolism and reduced phagolysosome maturation. Incorporation of DHA resulted in defective macrophage activation, as characterized by reduced production of pro-inflammatory cytokines (TNFα, IL-6 and MCP-1), and lower expression of co-stimulatory molecules (CD40 and CD86). DHA treatment impaired STAT1 phosphorylation and colocalization of the IFNγ receptor with lipid rafts, without affecting surface expression of IFNγ receptor. in response to activation by IFNγ, by modulation of IFNγ receptor signaling and function, suggesting that n-3 PUFA-enriched diets may have a detrimental effect on host immunity to tuberculosis

SREB, a GATA Transcription Factor That Directs Disparate Fates in Blastomyces dermatitidis Including Morphogenesis and Siderophore Biosynthesis

Blastomyces dermatitidis belongs to a group of human pathogenic fungi that exhibit thermal dimorphism. At 22°C, these fungi grow as mold that produce conidia or infectious particles, whereas at 37°C they convert to budding yeast. The ability to switch between these forms is essential for virulence in mammals and may enable these organisms to survive in the soil. To identify genes that regulate this phase transition, we used Agrobacterium tumefaciens to mutagenize B. dermatitidis conidia and screened transformants for defects in morphogenesis. We found that the GATA transcription factor SREB governs multiple fates in B. dermatitidis: phase transition from yeast to mold, cell growth at 22°C, and biosynthesis of siderophores under iron-replete conditions. Insertional and null mutants fail to convert to mold, do not accumulate significant biomass at 22°C, and are unable to suppress siderophore biosynthesis under iron-replete conditions. The defect in morphogenesis in the SREB mutant was independent of exogenous iron concentration, suggesting that SREB promotes the phase transition by altering the expression of genes that are unrelated to siderophore biosynthesis. Using bioinformatic and gene expression analyses, we identified candidate genes with upstream GATA sites whose expression is altered in the null mutant that may be direct or indirect targets of SREB and promote the phase transition. We conclude that SREB functions as a transcription factor that promotes morphogenesis and regulates siderophore biosynthesis. To our knowledge, this is the first gene identified that promotes the conversion from yeast to mold in the dimorphic fungi, and may shed light on environmental persistence of these pathogens

Novel derivative of aminobenzenesulfonamide (3c) induces apoptosis in colorectal cancer cells through ROS generation and inhibits cell migration

Background: Colorectal cancer (CRC) is the 3rd most common type of cancer worldwide. New anti-cancer agents are needed for treating late stage colorectal cancer as most of the deaths occur due to cancer metastasis. A recently developed compound, 3c has shown to have potent antitumor effect; however the mechanism underlying the antitumor effect remains unknown. Methods: 3c-induced inhibition of proliferation was measured in the absence and presence NAC using MTT in HT-29 and SW620 cells and xCELLigence RTCA DP instrument. 3c-induced apoptotic studies were performed using flow cytometry. 3c-induced redox alterations were measured by ROS production using fluorescence plate reader and flow cytometry and mitochondrial membrane potential by flow cytometry; NADPH and GSH levels were determined by colorimetric assays. Bcl2 family protein expression and cytochrome c release and PARP activation was done by western blotting. Caspase activation was measured by ELISA. Cell migration assay was done using the real time xCELLigence RTCA DP system in SW620 cells and wound healing assay in HT-29. Results: Many anticancer therapeutics exert their effects by inducing reactive oxygen species (ROS). In this study, we demonstrate that 3c-induced inhibition of cell proliferation is reversed by the antioxidant, N-acetylcysteine, suggesting that 3c acts via increased production of ROS in HT-29 cells. This was confirmed by the direct measurement of ROS in 3c-treated colorectal cancer cells. Additionally, treatment with 3c resulted in decreased NADPH and glutathione levels in HT-29 cells. Further, investigation of the apoptotic pathway showed increased release of cytochrome c resulting in the activation of caspase-9, which in turn activated caspase-3 and −6. 3c also (i) increased p53 and Bax expression, (ii) decreased Bcl2 and BclxL expression and (iii) induced PARP cleavage in human colorectal cancer cells. Confirming our observations, NAC significantly inhibited induction of apoptosis, ROS production, cytochrome c release and PARP cleavage. The results further demonstrate that 3c inhibits cell migration by modulating EMT markers and inhibiting TGFβ-induced phosphorylation of Smad2 and Samd3. Conclusions: Our findings thus demonstrate that 3c disrupts redox balance in colorectal cancer cells and support the notion that this agent may be effective for the treatment of colorectal cancer

Conservation of Complex Nuclear Localization Signals Utilizing Classical and Non-Classical Nuclear Import Pathways in LANA Homologs of KSHV and RFHV

ORF73 latency-associated nuclear antigen (LANA) of the Kaposi's sarcoma-associated herpesvirus (KSHV) is targeted to the nucleus of infected cells where it binds to chromatin and mediates viral episome persistence, interacts with cellular proteins and plays a role in latency and tumorigenesis. A structurally related LANA homolog has been identified in the retroperitoneal fibromatosis herpesvirus (RFHV), the macaque homolog of KSHV. Here, we report the evolutionary and functional conservation of a novel bi-functional nuclear localization signal (NLS) in KSHV and RFHV LANA. N-terminal peptides from both proteins were fused to EGFP or double EGFP fusions to examine their ability to induce nuclear transport of a heterologous protein. In addition, GST-pull down experiments were used to analyze the ability of LANA peptides to interact with members of the karyopherin family of nuclear transport receptors. Our studies revealed that both LANA proteins contain an N-terminal arginine/glycine (RG)-rich domain spanning a conserved chromatin-binding motif, which binds directly to importin β1 in a RanGTP-sensitive manner and serves as an NLS in the importin β1-mediated non-classical nuclear import pathway. Embedded within this domain is a conserved lysine/arginine-(KR)-rich bipartite motif that binds directly to multiple members of the importin α family of nuclear import adaptors in a RanGTP-insensitive manner and serves as an NLS in the classical importin α/β-mediated nuclear import pathway. The positioning of a classical bipartite kr-NLS embedded within a non-classical rg-NLS is a unique arrangement in these viral proteins, whose nuclear localization is critical to their functionality and to the virus life cycle. The ability to interact with multiple import receptors provides alternate pathways for nuclear localization of LANA. Since different import receptors can import cargo to distinct subnuclear compartments, a multifunctional NLS may provide LANA with an increased ability to interact with different nuclear components in its multifunctional role to maintain viral latency