TNF-α In Medium Research Articles

MicroRNA-146a-Mediated IL-6/Signal Transducer and Activator of Transcription 3 Signaling Pathway in Chondrocyte Proliferation and Apoptosis in Mice with Osteoarthritis

Background: To investigate the MicroRNA-146a targeting regulation of IL-6/STAT3 signaling pathway activity and influence the proliferation and apoptosis behavior-related mechanisms of OA chondrocytes. Material and Methods: 10 C57 mice were isolated and cultured with membrane protease and type II collagenase. The experiment was divided into blank group, MicroRNA-146a overexpression group and low expression group. The chondrocytes were transfected with plasmid vector. After 48 hours of culture, the proliferation rate of chondrocytes was detected by MTT method. The levels of type ii collagen, MMP-9, IL-1, IL-6, and TNF-α in culture medium were detected by ELISA. Luciferase reported experimental analysis of MircoRNA-146a targeting regulation of IL-6 genes. Results: Compared with the blank group, the proliferation rate of chondrocytes in the overexpression group was significantly decreased, the apoptosis rate was increased, the levels of IL-6 and p-STAT3 protein, type II collagen, MMP-9, IL-1, IL-6 and TNF-α were increased, while the low expression group was correlated (P < 0.05). Luciferase reporter experiments confirmed that MicroRNA-146a had a better binding effect with the IL-6 gene. Conclusion: MicroRNA-146a overexpression may mediate activation of IL-6/STAT3 signaling pathway and participate in decreased proliferation activity and increased apoptosis activity in OA chondrocytes. IL-6 gene may have targeted regulatory sites for MicroRNA-146a.

Combined Administration of TLR4 (LPS) and TLR3 (Poly I:C) Ligands to CBA Mice Elevates the Content of Osteogenic MSC by 1.6 Times and Increases Content of Bone Marrow MSC to Intermediate Level between Values Attained by Their Individual Administration.

In 1 and 24 h after combined administration of TLR4 (LPS) and TLR3 (Poly I:C) ligands to CBA mice, the content of MSC in bone marrow increased to intermediate value between the levels attained by their individual injections. The content of osteogenic MSC assessed in 24 h postinjection corresponded to the control level in Poly I:C group, decreased in LPS group by 2.5 times relatively to the control, and increased by 1.6 times (relatively to control) after combined administration of the ligands. In 3 h after combined addition of LPS and Poly I:C in vitro to 12-day-old primary culture of mouse bone marrow stromal cells, the concentration of TNFα in culture medium was intermediate between the levels attained by their individual application. The data revealed dependence of activation of stromal tissue on intensity of innate immunity reactions; they also attested to marked elevation of osteogenicity of MSC pool after costimulation with Poly I:C and LPS, which can underlie augmented calcification of the tissues during combined viral and bacterial infections.

Extracellular mitochondrial DNA promote NLRP3 inflammasome activation and induce acute lung injury through TLR9 and NF-κB.

Extracellular mitochondrial DNA (mtDNA) was demonstrated to be capable of inducing pulmonary inflammation through TLR9 while its role in NLRP3 inflammation activation remains unknown. C57BL/6 mice were challenged intratracheally with mtDNA. Pulmonary pathology, the NLRP3 and caspase-1 p20 in lung tissues were assayed. PMA-primed THP-1 macrophages were incubated with mtDNA in vitro and cell-free medium were concentrated to detect caspase-1 p20 subunit and NLRP3 by Western blotting. Additionally, IL-1β, L-18, TNF-α and caspase-1 activity in culture were also analyzed by ELISA kits and activity assay kit. Intratracheal administration of mtDNA increased NLRP3 and caspase-1 p20 subunit in lung together with excessive inflammation and damage. Inhibition of caspase-1 substantially diminished mtDNA-induced lung injury and inflammation. Exposed to mtDNA in THP-1 macrophages resulted in significant up-regulation of NLRP3 and increased caspase-1 p20 subunit release in culture. It also led to significant increased transcripts of NLRP3, ASC, caspase-1 and release of IL-1β, IL-18 and TNF-α in culture media. Futhermore, mtDNA exposure resulted in significant up-regulation of phosho -p38 MAPK and nucleus translocation of NF-κB. mtDNA-induced Transcripts of NLRP3 and ASC were inhibited by p38 siRNA inhibitor or NF-κB inhibitor. Extracellular mtDNA promote NLRP3 inflammasome activation, acute pulmonary inflammation and injury through TLR9, p38 MAPK and NF-κB pathways.

ACL/β2GPI and aPS/PT show synergic thrombogenic effects in suppressing anticoagulant activity of APC and stimulating tissue factor expression and TNF-α secretion by mononuclear cells

IntroductionPatients with systemic lupus erythematosus (SLE) possessing anti-phospholipid antibodies (aPLs) are often complicated by thrombotic vascular events. aPLs commonly associated with the complications are anti-cardiolipin/β2-glycoprotein I antibodies (aCL/β2GPI) and anti-phosphatidylserine/prothrombin antibodies (aPS/PT). However, the pathological mechanisms leading to thrombosis remain unclear. We explored clinical features of SLE patients with aCL/β2GPI and aPS/PT and investigated thrombogenic effects of their IgG fractions. Materials and methodsWe enrolled 97 SLE patients and 38 healthy control volunteers and performed activated protein C (APC) resistance screening test using their plasma samples. To detect the direct effect of aPLs IgG on APC, we developed an APC sensitivity ratio assay. Effects of aPLs IgG on monocytes were studied by measuring the surface expression of tissue factor (TF) and excretion of TNF-α from peripheral blood mononuclear cell culture. Results and conclusionThrombotic complications among SLE patients were closely associated with aCL/β2GPI or aPS/PT, with higher prevalence in patients with both antibodies. Addition of aPLs(+)-IgG to the APC sensitivity ratio assay led to significant suppression of the anticoagulant activity of APC. The suppression was more pronounced in double-positive cases. TF expression on monocytes and concentration of TNF-α in culture medium were increased by aPLs, again more pronounced in double-positive cases. These results indicate that the effects of aCL/β2GPI and aPS/PT are synergic both for APC anticoagulant activity and for production of TF and TNF-α from mononuclear cells. These modes of thrombogenic action of aPLs could be an important target for developing specific measures to prevent complications of SLE.

NEAT1 regulates MPP+-induced neuronal injury by targeting miR-124 in neuroblastoma cells

Long non-coding RNAs (lncRNAs) have been reported to play important roles in Parkinson’s disease (PD) pathogenesis. It was indicated that lncRNA nuclear enriched abundant transcript 1 (NEAT1) is involved in PD. However, the underlying mechanism of NEAT1 is still not fully explored. Human neuroblastoma cell line SH-SY5Y was treated with 1-Methyl-4-phenylpyridinium (MPP+) to mimic PD model in vitro. qRT-PCR was employed to detect the expression of NEAT1, IL-1β, IL-6 and TNF-α. Starbase database, RNA pull-down assay and RNA immunoprecipitation (RIP) assay were performed to verify the relationship between NEAT1 and miR-124. MTT assay and flow cytometry assay were used to detect cell viability and apoptosis. Elisa was introduced to measure the levels of IL-1β, IL6 and TNF-α in culture media. We found that NEAT1 expression was significantly increased in SH-SY5Y cells after MPP+ treatment in dose- and time- dependent manners. MPP+ induced the expression and secretion of IL-1β, IL-6 and TNF-α, inhibited cell viability and induced apoptosis while these effects could be rescued by NEAT1 silencing. miR-124 was a target of NEAT1. Anti-miR-124 could reverse the effects caused by NEAT1 knockdown in MPP+ treated SH-SY5Y cells. Therefore, we speculated that NEAT1 may regulate MPP+ induced neuronal injury by targeting miR-124 in SH-SY5Y cells.

Participation of TNF-α in Inhibitory Effects of Adipocytes on Osteoblast Differentiation.

Mesenchymal stem cells from bone marrow (BM-MSCs) and adipose tissue (AT-MSCs) are attractive tools for cell-based therapies to repair bone tissue. In this study, we investigated the osteogenic and adipogenic potential of BM-MSCs and AT-MSCs as well as the effect of crosstalk between osteoblasts and adipocytes on cell phenotype expression. Rat BM-MSCs and AT-MSCs were cultured either in growth, osteogenic, or adipogenic medium to evaluate osteoblast and adipocyte differentiation. Additionally, osteoblasts and adipocytes were indirectly co-cultured to investigate the effect of adipocytes on osteoblast differentiation and vice versa. BM-MSCs and AT-MSCs exhibit osteogenic and adipogenic potential under non-differentiation-inducing conditions. When exposed to osteogenic medium, BM-MSCs exhibited higher expression of bone markers compared with AT-MSCs. Conversely, under adipogenic conditions, AT-MSCs displayed higher expression of adipose tissue markers compared with BM-MSCs. The presence of adipocytes as indirect co-culture repressed the expression of the osteoblast phenotype, whereas osteoblasts did not exert remarkable effect on adipocytes. The inhibitory effect of adipocytes on osteoblasts was due to the release of tumor necrosis factor alpha (TNF-α) in culture medium by adipocytes. Indeed, the addition of exogenous TNF-α in culture medium repressed the differentiation of BM-MSCs into osteoblasts mimicking the indirect co-culture effect. In conclusion, our study showed that BM-MSCs are more osteogenic while AT-MSCs are more adipogenic. Additionally, we demonstrated the key role of TNF-α secreted by adipocytes on the inhibition of osteoblast differentiation. Thus, we postulate that the higher osteogenic potential of BM-MSCs makes them the first choice for inducing bone repair in cell-based therapies.

Hepatic metabolic response of Holstein cows in early and mid lactation is altered by nutrient supply and lipopolysaccharide in vitro

The metabolic response of the liver during periods of inflammation is poorly understood. The objective of this study was to characterize the effects of nutrient supply and lipopolysaccharide (LPS) challenge on hepatic intermediate metabolism of early- and mid-lactation cows by employing gas chromatography-mass spectrometry with stable isotope tracer. Twelve multiparous Holstein-Friesian cows in early (n=6; 12±4.2 d in milk) and mid (n=6; 115±13.5 d in milk) lactation were used for this study. Liver biopsies were performed on all cows. Liver slices (40–60mg) were incubated in a 37°C water bath for 2 h with either control (phosphate buffered saline), pyruvate (PYR; 1mM unlabeled pyruvate and 1mM [13C3]pyruvate), pyruvate + propionate (PYR+PRO; 1mM unlabeled pyruvate, 1mM [13C3]pyruvate, and 2mM sodium propionate), or pyruvate + AA (PYR+AA; 1mM unlabeled pyruvate, 1mM [13C3]pyruvate, and 2mM AA solution), and LPS (0.0 or 0.2μg/mL) was added to flasks per treatment. Enrichment of isotopomers in metabolic equilibrium with Krebs cycle intermediates was assessed. Pyruvate fluxes and the enzymatic activity of pyruvate carboxylase (PC) versus pyruvate dehydrogenase (PDH) and phosphoenol pyruvate carboxykinase (PEPCK) were calculated. Media were analyzed for concentrations of tumor necrosis factor-α (TNF-α), glucose, and haptoglobin. Data were analyzed as randomized block (stage of lactation) design in a factorial arrangement of nutrient treatments by LPS dose. Challenge with LPS increased the mRNA abundance of TNF-α, haptoglobin, and serum amyloid A 2, and the concentration of TNF-α in media. Challenge with LPS increased mRNA abundance of PC but reduced the enrichment of 13C1[M1] and 13C2[M2]alanine and tended to reduce the enzymatic activity of PEPCK. Incubation with PYR+PRO and PYR+AA increased the flux of pyruvate to acetyl CoA. However, only PYR+PRO increased the enzymatic activity of PEPCK and PDH versus PC and decreased the mRNA abundance of PC. Cows in early lactation tended to receive a greater contribution of pyruvate to the oxaloacetate flux via the lower PDH versus PC activity and a higher mRNA abundance of PC than cows in mid lactation. Our results suggest that regardless of stage of lactation and nutrient supplement, hepatic gluconeogenesis was impaired during inflammation. Further research examining how various nutrients support liver function and improve the immunometabolic response of liver during inflammation is warranted.

Glucose supplementation has minimal effects on blood neutrophil function and gene expression in vitro

During early lactation, glucose availability is low and the effect of glucose supply on bovine polymorphonuclear leukocyte (PMNL) function is poorly understood. The objective of this study was to determine the effect of glucose supplementation on the function and transcriptomic inflammatory response of PMNL from cows in early and mid-lactation in vitro. Twenty Holstein cows in early (n=10; days in milk=17±3.1) and mid-lactation (n=10; days in milk=168±14.8) were used for this study. Jugular blood was analyzed for serum concentrations of nonesterified fatty acids, β-hydroxybutyrate, and glucose. Polymorphonuclear leukocytes were isolated and diluted using RPMI (basal glucose concentration was 7.2 mM) to different concentrations of PMNL/mL for phagocytosis, chemotaxis, gene expression, and medium analyses. Working solutions of glucose (0 or 4 mM of d-glucose) and lipopolysaccharide (0 or 50μg/mL) were added and tubes were incubated for 120 min at 37°C. Media were analyzed for concentrations of glucose and tumor necrosis factor-α (TNF-α). Data were analyzed in a randomized block (stage of lactation) design. Challenge with lipopolysaccharide increased the expression of the genes encoding for nuclear factor kappa B (NFKB1), IL-10 (IL10), IL1B, IL6, IL8, TNF-α (TNFA), glucose transporter 3 (SLC2A3), and the concentration of TNF-α in medium (147.3 vs. 72.5 pg/mL for lipopolysaccharide and control, respectively). Main effect of stage of lactation was minimal where the expression of IL10 increased for cows in early compared with cows in mid-lactation. After lipopolysaccharide challenge, cows in early lactation experienced more marked increases in the expression of IL6, TNFA, and IL8 when compared with cows in mid-lactation. Glucose supplementation had minimal effects on gene expression where glucose supplementation increased the expression of lysozyme (LYZ). Glucose supplementation increased PMNL phagocytosis but did not alter chemotaxis, morphology, or concentration of TNF-α in the medium. Under the conditions of the experiment, stage of lactation had minimal effects on PMNL response to glucose supply where only the expression of NFKB1 and the production of TNF-α were greater for cows in mid-lactation when compared with early lactation. Metabolic profiles for cows in early lactation did not parallel those for cows during the early postpartum period and may partly explain results for this study. Future studies investigating the effect of glucose supply on bovine PMNL function in vivo and how this may be altered by stage of lactation are warranted.

Endothelin-1 overexpression exacerbate experimental allergic encephalomyelitis

BackgroundMultiple sclerosis (MS) is a CNS inflammatory demyelinating disorder. T helper 1 (Th1) and T helper 17 (Th17) cells are important in MS immunopathogenesis. Level of endothelin-1 (ET-1), a potent vasoconstrictor, is increased in sera of MS patients. We studied the role of ET-1 in experimental allergic encephalomyelitis (EAE), a MS animal model. MethodsEAE is induced in transgenic mice overexpressing endothelial ET-1 (TET-1), transgenic mice overexpressing astrocytic ET-1 (GET-1) and non-transgenic (NTg) mice by immunization with myelin oligodendrocyte glycoprotein (MOG)35–55 peptide. EAE scores, spinal cord histology, serum proinflammatory cytokines levels, and proinflammatory cytokines production from splenocytes of ET-1 transgenic and NTg mice with EAE were studied. ResultsET-1 transgenic mice developed more severe EAE than NTg with increased inflammation and demyelination in spinal cord. The mean maximum EAE scores for GET-1, TET-1 and NTg mice with EAE were 4.84, 4.31 and 4.05 respectively (p<0.05). Serum levels of IL-6, IL-17A, IFN-γ and TNF-α were higher in ET-1 transgenic than NTg mice with EAE (p<0.05) while serum IL-4 levels were similar. mRNA levels of IL-6, IL-17A, IFN-γ and TNF-α from cultured splenocytes were higher in ET-1-transgenic than NTg mice with EAE (p<0.05) while IL-4 mRNA levels were similar. Consistently, levels of IL-6, IL-17A, IFN-γ and TNF-α in culture media of splenocytes were higher in ET-1 transgenic than NTg mice with EAE (p<0.05) while IL-4 levels were similar. ConclusionsMice with endothelial or astrocytic ET-1 overexpression developed more severe EAE with increased splenic lymphocyte production of Th1 and Th17 proinflammatory cytokines.

Cyclosporin-A Induced Toxicity in Rat Renal Collecting Duct Cells: Interference with Enhanced Hypertonicity Induced Apoptosis

Background/ Aims: Rat renal inner medullary collecting duct (IMCD) cells are physiologically exposed to a wide range of ambient tonicity. To maintain their function upon changes in osmolality, IMCD cells induce expression of osmoprotective and antiapoptotic genes, mainly mediated by the transcription factor Tonicity Enhancer Binding Protein (TonEBP). Some drugs like Cyclosporin-A (CsA) are discussed to interfere with the activity of TonEBP and thereby mediate their nephrotoxic effects. The aim of our study was to further understand CsA toxicity during elevation of ambient osmolality. Methods: First we examined cytotoxicity of CsA in IMCD exposed to elevated tonicity. Employing microarray analysis of gene expression, real-time PCR and immunoassays, we scrutinized pathways contributing to this effect. Results: We show that in IMCD cells CsA but not FK506 increases apoptosis upon an increase in tonicity. This effect is independent of cellular TonEBP localization or activity and reactive oxygen species. Microarray studies revealed marked quantitative differences in gene expression. Functional analysis showed overrepresentation of genes associated with cell death in presence of CsA. This correlated with increased mRNA expression of genes associated with the death receptor pathway and detection of TNFΑ in culture medium of cells treated with CsA. Conclusion: Our results show that CsA cytotoxicity is induced under elevated ambient osmolality and that death receptor signaling probably contributes to CsA cytotoxicity.

Effects of three anti-TNF-α drugs: Etanercept, infliximab and pirfenidone on release of TNF-α in medium and TNF-α associated with the cell in vitro

Tumor necrosis factor-alpha (TNF-α) is a vital component of the inflammatory process and its aberrant over-expression has been linked to numerous disease states. New treatment strategies have sought to reduce circulating TNF-α, either with neutralizing anti-TNF-α binding proteins such as etanercept or via drugs that inhibit de novo TNF-α synthesis like pirfenidone. In the present study, we examined the effects of both classes of drugs on secreted and cell-associated TNF-α produced by THP-1 cells. All of the tested drugs significantly reduced secreted levels of bioactive TNF-α following stimulation with LPS as measured by bioassay. However, etanercept-treated cells had approximately six-fold higher levels of cell-associated TNF-α compared with that of the LPS-alone treatment group. Surprisingly, LPS+infliximab treated cells did not increase cell-associated TNF-α relative to the LPS-alone treatment. Pirfenidone significantly reduced both secreted and cell-associated TNF-α levels. These drug-related differences in cell-associated TNF-α may have broad implications in the future for the therapeutic uses of anti-TNF-α drugs in the management of TNF-α diseases.

Regulation of Chemokine Expression by NaCl Occurs Independently of Cystic Fibrosis Transmembrane Conductance Regulator in Macrophages

Chronic pulmonary inflammation and infection are the leading causes of morbidity and mortality in cystic fibrosis (CF). While the effect of mutation of the cystic fibrosis transmembrane conductance regulator (CFTR) on airways remains controversial, some groups have demonstrated increases in Na(+) and Cl(-) in CF airway surface liquid compared to normal airways. We investigated the consequences of NaCl on pro-inflammatory chemokine and cytokine production by macrophages. Stimulation of mouse macrophages with increasing amounts of NaCl induced macrophage inflammatory protein-2 (MIP-2) and tumor necrosis factor-alpha (TNF-alpha) production. Further, co-incubation of macrophages with NaCl in the presence of either lipopolysaccharide (LPS) or TNF-alpha synergistically increased MIP-2 production. Both the NaCl and NaCl plus LPS responses were partially dependent on endogenous production and autocrine signaling by TNF-alpha. To investigate the role of CFTR in MIP-2 production, we compared the responses of wild-type and DeltaF508 CF mouse macrophages to NaCl and LPS. The responses of macrophages from both strains were indistinguishable. In addition, CFTR mRNA was not expressed in macrophages. Taken together, these findings suggest that NaCl stimulates MIP-2 production by macrophages through a mechanism that is partially dependent on TNF-alpha but independent of macrophage CFTR expression.

Cutting Edge: Enhanced Pulmonary Clearance of Pseudomonas aeruginosa by Muc1 Knockout Mice

MUC1 (MUC1 in human and Muc1 in nonhumans) is a membrane-tethered mucin that interacts with Pseudomonas aeruginosa (PA) through flagellin. In this study, we compared PA pulmonary clearance and proinflammatory responses by Muc1(-/-) mice with Muc1(+/+) littermates following intranasal instillation of PA or flagellin. Compared with Muc1(+/+) mice, Muc1(-/-) mice showed increased PA clearance, greater airway recruitment of neutrophils, higher levels of TNF-alpha and KC in bronchoalveolar lavage fluid, higher levels of TNF-alpha in media of flagellin-stimulated alveolar macrophages, and higher levels of KC in media of tracheal epithelial cells. Knockdown of MUC1 enhanced flagellin-induced IL-8 production by primary human bronchial epithelial cells. Expression of MUC1 in HEK293T cells attenuated TLR5-dependent IL-8 release in response to flagellin, which was completely ablated when its cytoplasmic tail was deleted. We conclude that MUC1/Muc1 suppresses pulmonary innate immunity and speculate its anti-inflammatory activity may play an important modulatory role during microbial infection.

TNF-α Stimulates Matrix Metalloproteinase Expression in Myelodysplastic Syndromes (MDS): Therapeutic Potential for Inhibitors of TNF-α and MMPs.

MDS is characterized by ineffective hematopoiesis with increased intramedullary apoptosis which has been correlated in turn with high levels of tumor necrosis factor (TNF)- α. Previously, we showed that TNF-α strongly upregulates the secretion of the matrix metalloproteinases (MMP)-2 and -9 in normal CD34+ cells. Elevated expression of MMPs has been suggested to contribute to cancer progression and leukemic dissemination and MMPs also facilitate the secretion of TNF-α. In this work, we hypothesized that TNF-α-induced MMP production plays a role in the progression of MDS. We therefore examined the effects of recombinant human (rh) TNF-α on the expression and secretion of MMP-2, MMP-9 and membrane type (MT) 1-MMP (known activator of MMP-2), by MNC from MDS patients (using RT-PCR, zymography and Western blotting), as well as the effects of TNF-α on migration of MDS MNC across the reconstituted basement membrane Matrigel. We observed higher mean levels of TNF-α in media conditioned by mononuclear cells (MNC) obtained from 20 patients diagnosed with MDS (RAEB-T (4); RAEB (5), RA (10) and RARS (1)) in comparison to normal controls. We found that (i) MMP-9 is secreted by MDS MNC and this secretion is increased by TNF-α, (ii) MT1-MMP is expressed by the majority of MDS MNC and this expression is upregulated by TNF-α, and (iii) MMP-2 is detectable only in RAEB-T MNC samples and is activated by TNF-α. TNF-α also stimulated the migration of MDS MNC across Matrigel, which was inhibited by the inhibitor of MT1-MMP, epigallocatechin-3-gallate. Moreover, Enbrel (soluble TNF receptor fusion protein), which blocks TNF-α, also inhibited the expression of MT1-MMP and secretion of MMP-9 by MDS MNC as well as their migration across Matrigel. In addition, we observed increased activation of the latent form of MMP-2 in co-cultures of MDS MNC with bone marrow fibroblastic cells. We suggest that in MDS patients, TNF-α stimulates the expression of MMP-9 and MT1-MMP, inducing a highly proteolytic environment in bone marrow which could further increase processing and secretion of endogenous TNF-α. Therefore, we suggest that use of TNF-α inhibitors combined with MMP inhibitors could have therapeutic value in abrogating the progression of MDS.

Effects of β-glucan extracted from Saccharomyces cerevisiae on humoral and cellular immunity in weaned piglets

Twenty-four barrows were used to investigate the effects of β-glucan on immune function in weaned piglets. Pigs (8.09 ± 0.20 kg, 28 d of age) were fed a diet without or with supplemented β-glucan (50 mg/kg feed). All pigs were injected with ovalbumin (OVA) on day 14 to investigate their humoral immune response. On day 28, lymphocytes were isolated from all pigs to determine the effects of β-glucan on cellular immunity of pigs in vitro. Lymphocytes from six pigs of each group were incubated with 16 μg lipopolysaccharide (LPS) per ml culture medium, the remainder with an equivalent volume of culture medium alone. Samples were collected at 0, 3, 6, 12, 18, 24, and 48 h after LPS addition for determination of interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), and interleukin-10 (IL-10). On day 31, six pigs of each group were injected with either LPS (25 μg/kg BW) or an equivalent amount of sterile saline. Blood samples were collected at 3 h after LPS injection for analysis of IL-6, TNF-α, and IL-10 in plasma. The results indicated that dietary β-glucan enhanced pig antibody response to OVA only in the first week after injection. In vitro, the increases of IL-6 and TNF-α in culture medium were partially dampened in pigs supplemented with β-glucan when their lymphocytes were incubated with LPS, whereas the increase of IL-10 was potentiated. In vivo, dietary β-glucan attenuated the increase of plasma IL-6 and TNF-α, and enhanced the increase of plasma IL-10 when pigs were challenged with LPS. These results demonstrate that β-glucan can improve the humoral immunity of pigs and modulate cellular immunity of pigs by mitigating the elevation of pro-inflammatory cytokines and enhancing the increase of anti-inflammatory cytokines after an immunological challenge.

Effects of the β-Amyloid and Carboxyl-terminal Fragment of Alzheimer's Amyloid Precursor Protein on the Production of the Tumor Necrosis Factor-α and Matrix Metalloproteinase-9 by Human Monocytic THP-1

To explore the direct role of beta-amyloid (Abeta) and carboxyl-terminal fragments of amyloid precursor protein in the inflammatory processes possibly linked to neurodegeneration associated with Alzheimer's disease, the effects of the 105-amino acid carboxyl-terminal fragment (CT(105)) of amyloid precursor protein on the production of tumor necrosis factor-alpha (TNF-alpha) and matrix metalloproteinase-9 (MMP-9) were examined in a human monocytic THP-1 cell line and compared with that of Abeta. CT(105) elicited a marked increase in TNF-alpha and MMP-9 production in the presence of interferon-gamma in a dose- and time-dependent manner. Similar patterns were obtained with Abeta despite its low magnitude of induction. Autocrine TNF-alpha is likely to be a main mediator of the induction of MMP-9 because the neutralizing antibody to TNF-alpha inhibits MMP-9 production. Genistein, a specific inhibitor of tyrosine kinase, dramatically diminished both TNF-alpha secretion and subsequent MMP-9 release in response to CT(105) or Abeta. Furthermore, PD98059 and SB202190, specific inhibitors of ERK or p38 MAPK respectively, efficiently suppressed CT(105)-induced effects whereas only PD98059 was effective at reducing Abeta-induced effects. Our results suggest that CT(105) in combination with interferon-gamma might serve as a more potent activator than Abeta in triggering inflammatory processes and that both tyrosine kinase and MAPK signaling pathways may represent potential therapeutic targets for the control of Alzheimer's disease progression.

CYP2E1-mediated modulation of valproic acid-induced hepatocytotoxicity

Objectives: To determine the cytotoxicity of valproic acid (VPA) and its metabolite, 4-ene-valproic acid (4-ene-VPA) in human hepatoblastoma cells (Hep G2), and to study the modulatory effect of cytochrome P450 2E1 induction in this model. Methods: Cells were exposed to VPA or 4-ene-VPA in the presence of either ethanol (EtOH), or EtOH combined with disulphiram (DS). Some cells were exposed to α-fluoro-VPA or to α-fluoro-4-ene-VPA in the absence of CYP2E1 inducers. Apoptosis and necrosis were measured by analyzing 6000 cells per sample using transmission electron microscopy, while cytokine release and apoptosis were quantitated by ELISA. Results: VPA + EtOH increased VPA cytotoxicity. 4-ene-VPA + EtOH significantly increased toxicity, while DS + EtOH significantly reduced this toxicity. Alpha-fluorinated analogues reduced cytotoxicity compared to the corresponding VPA compounds. Neither VPA nor α–fluorinated VPA increased the release of IL-6 or TNF-α in media. A significant increase in the release of TNF-α was observed in cells exposed to 4-ene-VPA that further increased with EtOH exposure. Conclusions: Cells exposed to 4-ene-VPA experience greater cytotoxicity than those treated with VPA. Cytochrome P450 2E1 inducers enhance toxicity in VPA-exposed cells, while α-fluorination of VPA diminishes cytotoxicity by directly interfering with the β-oxidation of the 4-ene-VPA metabolite.

The production of superoxide anion and nitric oxide by cultured murine leukocytes and the accumulation of TNF-α in the conditioned media is inhibited by taurine chloramine

Taurine chloramine (Tau-C1) inhibits production of nitric oxide (NO) by activated peritoneal macrophages and attenuates accumulation of tumor necrosis factor-alpha (TNF-α) in the culture media, similar to that previously reported for activated RAW 264.7 cells. In addition, the effect of Tau-C1 and taurine on superoxide anion (O2−) production in murine peritoneal exudate polymorphonuclear leukocytes (PMN) was examined. Tau-C1 inhibited O2− production in a manner that was dose-dependent and reversible. Taurine also inhibited O2− production by stimulated PMN, but at higher concentrations and to a lesser extent than Tau-Cl. The effects of taurine on O2− production was attributed to the in vitro formation of Tau-Cl catalyzed by PMN associated halide-dependent myeloperoxidase. In contrast, production of NO by activated peritoneal macrophages and accumulation of TNF-α in the media was inhibited by Tau-C1 while taurine was without effect. These data lend support to the notion that Tau-C1 may participate in the inflammatory response by modulating production of inflammatory mediators.