Expression of mRNA for interleukin-1beta, interleukin-6, tumor necrosis factor-alpha and macrophage migration inhibitory factor in HPA-axis tissues in Schistosoma mansoni-infected baboons (Papio cynocephalus)

Cytokines may regulate the function of the hypothalamic-pituitary-adrenal axis during schistosomiasis. This possibility was investigated in baboons experimentally infected with Schistosoma mansoni. Serum levels of corticotrophin-releasing hormone, adrenocorticotrophin, cortisol and dehydroepiandrosterone were confirmed to be decreased in infected baboons as previously shown. To explore if this effect is associated with specific expression of cytokines with endocrine activity, and are also associated with the pathology of the disease, Northern blots for interleukin-1beta, interleukin-6, tumor necrosis factor-alpha and macrophage migration inhibitory factor in hypothalamic-pituitary-adrenal axis tissues were performed. Infection induced interleukin-1beta gene expression in the hypothalamus, while interleukin-6 and migration inhibitory factor mRNAs were induced only in the pituitary and adrenal glands. Tumor necrosis factor-alpha gene expression was induced in the hypothalamus and the pituitary gland. Histopathological analysis of the hypothalamic-pituitary-adrenal axis tissues in infected and control baboons revealed no morphological differences between them. These results suggest that specific cytokines expressed in hypothalamic-pituitary-adrenal axis tissues could regulate hormone secretion during schistosomiasis.     

Amyloid beta and amylin fibrils induce increases in proinflammatory cytokine and chemokine production by THP-1 cells and murine microglia

Activated microglia surrounding amyloid beta-containing senile plaques synthesize interleukin-1, an inflammatory cytokine that has been postulated to contribute to Alzheimer's disease pathology. Studies have demonstrated that amyloid beta treatment causes increased cytokine release in microglia and related cell cultures. The present work evaluates the specificity of this cellular response by comparing the effects of amyloid beta to that of amylin, another amyloidotic peptide. Both lipopolysaccharide-treated THP-1 monocytes and mouse microglia showed significant increases in mature interleukin-1beta release 48 h following amyloid beta or human amylin treatment, whereas nonfibrillar rat amylin had no effect on interleukin-1beta production by THP-1 cells. Lipopolysaccharide-stimulated THP-1 cells treated with amyloid beta or amylin also showed increased release of the proinflammatory cytokines tumor necrosis factor-alpha and interleukin-6, as well as the chemokines interleukin-8 and macrophage inflammatory protein-1alpha and -1beta. THP-1 cells incubated with fibrillar amyloid beta or amylin in the absence of lipopolysaccharide also showed significant increases of both interleukin-1beta and tumor necrosis factor-alpha mRNA. Furthermore, treatment of THP-1 cells with amyloid fibrils resulted in an elevated expression of the immediate-early genes c-fos and junB. These studies provide further evidence that fibrillar amyloid peptides can induce signal transduction pathways that initiate an inflammatory response that is likely to contribute to Alzheimer's disease pathology.     

Spatiotemporal pattern of neuroinflammation after impact-acceleration closed head injury in the rat

Inflammatory processes have been implicated in the pathogenesis of traumatic brain damage. We analyzed the spatiotemporal expression pattern of the proinflammatory key molecules: interleukin-1beta, interleukin-6, tumor necrosis factor-alpha, and inducible nitric oxide synthase in a rat closed head injury (CHI) paradigm. 51 rats were used for RT-PCR analysis after CHI, and 18 for immunocytochemistry. We found an early upregulation of IL-1beta, IL-6, and TNF-alpha mRNA between 1h and 7h after injury; the expression of iNOS mRNA only revealed a significant increase at 4h. After 24h, the expression decreased towards baseline levels, and remained low until 7d after injury. Immunocytochemically, IL-1beta induction was localized to ramified microglia in areas surrounding the primary impact place as well as deeper brain structures. Our study shows rapid induction of inflammatory gene expression that exceeds by far the primary impact site and might therefore contribute to tissue damage at remote sites.     

Elevation of Cyclic AMP Levels in Astrocytes Antagonizes Cytokine-Induced Adhesion Molecule Expression

Abstract: We have examined the effect of elevating cyclic AMP levels on cytokine-mediated enhancement of intercellular adhesion molecule-1 (ICAM-1) and vascular cell adhesion molecule-1 (VCAM-1) gene expression by astrocytes. Treatment of astrocytes with the cyclic AMP mimetic dibutyryl-cyclic AMP, or the agonists norepinephrine, forskolin, prostaglandin E₂, and cholera toxin alone had no effect on ICAM-1 or VCAM-1 mRNA gene expression. However, elevating cyclic AMP levels within the cells by these agents suppressed interleukin-1β- and tumor necrosis factor-α-induced adhesion molecule expression at both the mRNA and protein levels. The phosphodiesterase type IV inhibitor, rolipram, was able to potentiate the inhibitory effect of forskolin on ICAM-1 and VCAM-1 gene expression. Inhibition of tumor necrosis factor-α-induced VCAM-1 mRNA levels by forskolin was partially due to enhanced degradation of VCAM-1 message, whereas the decay rates of tumor necrosis factor-α-induced ICAM-1 message and interleukin-1β-induced ICAM-1/VCAM-1 message were not affected by forskolin treatment. These results demonstrate that the pathways used by interleukin-1β and tumor necrosis factor-α to induce adhesion molecule expression are antagonized by cyclic AMP-dependent protein kinase-mediated signaling pathways.     

Effects of centimeter waves on the immune system of mice in endotoxic shock

The effects of centimeter waves (8.15-18 GHz, 1 microW/cm2, 1 h daily for 10 days; MW) on the production of the tumor necrosis factor alpha, interleukin-lalpha, interleukin-1beta, interleukin-2, and the expression of interleukin-6, interleukin-10, interferon-gamma, nitric oxide and HSP27, HSP72 and HSP90alpha in mice irradiated before or after LPS injection were studied. An acute endotoxic model was produced by a single LPS injection. The effects of microwaves on nitric oxide, interleukin-6, tumor necrosis factor-alpha, and interferon-gamma were dependent on the functional status of exposed animals. Thus, an exposure of healthy mice to microwaves for 10 days was followed by a decrease in nitric oxide and interferon-gamma production, and an increase in the production of the tumor necrosis factor-alpha and interleukin-6. On the contrary, an exposure to MW before intoxication resulted in an increase in the synthesis of nitric oxide and interferon-gamma as well as a decrease in the concentration of the tumor necrosis factor-alpha and interleukin-6 in blood of mice in endotoxic shock. When microwave exposure was used after LPS injection, it did not provide any protective effect, and preliminary irradiation enhanced the resistance of the organism to endotoxic shock.     

Tumor necrosis factor and interleukin-1 induce activin A gene expression in a human bone marrow stromal cell line.

Activin A, a homodimer of the beta A chain, regulates hematopoiesis. In a human bone marrow-derived stromal cell line, KM-102, phorbol myristate acetate, tumor necrosis factor-alpha and interleukin-1 beta induced great increases in beta A chain mRNA levels and production of activin A activities. The phorbol ester-induced beta A chain gene expression was inhibited by cycloheximide and down regulation of protein kinase C, whereas the cytokine-induced expression was little affected by these treatments. These results indicate that the inflammatory cytokines directly stimulate beta A chain gene expression via protein kinase C-independent pathways.     

The role of lipolysis in mediating the proinflammatory effects of very low density lipoproteins in mouse peritoneal macrophages

Hypertriglyceridemia is an important risk factor for atherosclerosis, especially in obesity. Macrophages are one of the primary cell types involved in atherogenesis and are thought to contribute to lesion formation through both lipid accumulation and proinflammatory gene expression. In this study, we sought to determine the direct impact of triglyceride (TG)-rich VLDL-induced lipid accumulation on macrophage proinflammatory processes. Incubation of mouse peritoneal macrophages with 100 microg/ml VLDL for 6 h led to 2.8- and 3.7-fold increases in intracellular TGs and FFAs, respectively (P < 0.05). The inflammatory proteins tumor necrosis factor-alpha, interleukin-1beta, monocyte chemoattractant protein-1, intercellular adhesion molecule-1, matrix metalloproteinase 3 (MMP3), and macrophage inflammatory protein-1alpha (MIP-1alpha) were all upregulated by at least 2-fold (P < 0.05) in a dose-dependent manner in VLDL-treated macrophages. The increase in inflammatory gene expression coincided with the phosphorylation of the mitogen-activated protein kinase (MAPK) pathway members extracellular signal-regulated kinase (ERK) 1/2, stress-activated protein kinase/c-Jun NH2-terminal kinase, and p38 MAPK and was ameliorated by U0126, an inhibitor of ERK1/2. Inhibition of extracellular TG hydrolysis with tetrahydrolipstatin (Orlistat) resulted in the absence of intracellular TG and FFA accumulation and was accompanied by the amelioration of ERK1/2 phosphorylation and MIP-1alpha gene expression. These data indicate that VLDL hydrolysis, and the subsequent accumulation of intracellular FFAs and TGs, plays a substantive role in mediating the proinflammatory effects of VLDL. These data have important implications for the direct proatherogenic effects of VLDL on macrophage-driven atherosclerosis.     

Estrogen reduces pro-inflammatory cytokines in rodent adipose tissue: studies in vivo and in vitro.

Obesity is associated with an increased risk of developing insulin resistance, Type 2 diabetes, and cardiovascular disease. Reports have suggested that adipose tissue-derived cytokines such as tumor necrosis factor-alpha, interleukin-6 and interleukin-8 could be involved in the development of these health complications. Since estrogen has been suggested to attenuate the development of atherosclerosis and cardiovascular disease, we investigated whether ovariectomy affected the production and release of these three adipose tissue-derived cytokines with and without estrogen replacement in vivo and in vitro. Female Wistar rats were submitted to either a) ovariectomy, b) ovariectomy and estrogen replacement, or c) sham operation. After five months, animals were sacrificed and parametrial adipose tissue was removed and incubated for up to 24 hours with either interleukin-1beta (IL-1beta) (5 micro g/l), dexamethasone (50 nM) or estrogen (50 nM). Ovariectomy significantly increased interleukin-6 gene expression (p < 0.05) as well as interleukin-8 protein levels (p < 0.05) and gene expression (p < 0.05) in the adipose tissue, and estrogen replacement significantly reversed this increase (p < 0.05). However, no direct effects of estrogen were found in in vitro adipose tissue incubations. Neither ovariectomy nor estrogen replacement had any effects on tumor necrosis factor-alpha protein levels or gene expression. In conclusion, estrogen-deficient rats were found to have increased production of interleukin-6 and interleukin-8, which could be attenuated by estrogen-replacement. Since estrogen is suggested to be anti-atherosclerotic, this effect might be caused by a reduction in cytokine production from the adipose tissue.     

Expression of APOBEC2 is transcriptionally regulated by NF-kappaB in human hepatocytes

Apolipoprotein B mRNA-editing enzyme catalytic subunit 2 (APOBEC2) is a member of the nucleic-acid-editing enzymes. However, the physiological function of APOBEC2 remains unclear. We demonstrate that APOBEC2 expression is strongly enhanced in response to both tumour necrosis factor-alpha (TNF-alpha) and interleukin-1beta. Inhibition of NF-kappaB activation invariably blocks TNF-alpha-induced APOBEC2 expression. The promoter region of APOBEC2 contains functional NF-kappaB response elements in the 5' untranslated region of the gene at -625/-616. These results show that APOBEC2 expression is regulated by pro-inflammatory cytokines via NF-kappaB activation and suggest a possible role of APOBEC2 in the pathophysiology of hepatic inflammation.     

Proteasome from cytokine-treated human cells shows stimulated BrAAP activity and depressed PGPH activity.

The branched chain amino acid-preferring (BrAAP) activity of multicatalytic proteinase complex isolated from human umbilical vein endothelial cells and treated with interferon-gamma was increased more than 2-fold, which was associated with a marked increase in LMP7 expression and decreased peptidylglutamyl peptide-hydrolyzing activity. Increases in BrAAP activity in supernatants from cells treated with interferon-gamma, tumor necrosis factor-alpha, interleukin-1 beta, interleukin-6, or lipopolysaccharide paralleled the increases in LMP7 expression. These findings are consistent with the conclusion that the increased BrAAP activity of LMP-containing multicatalytic proteinase complex results from incorporation of LMP7 or other LMP subunits.     

The synthetic melanocortin (CKPV)2 exerts broad anti-inflammatory effects in human neutrophils

Natural melanocortin peptides exert broad effects on the host and they have remarkable therapeutic potential. However, successful use of melanocortins as therapeutic agents depends on the design of molecules that have more stable pharmacological profiles. The synthetic peptide (CKPV)(2), based on the C-terminal sequence of alpha-melanocyte stimulating hormone (alpha-MSH), has anti-tumor necrosis factor-alpha (TNF-alpha) effects in vitro and in vivo and is a promising candidate to treat inflammation. Because neutrophil activity is a major target for anti-inflammatory therapies, we determined whether (CKPV)(2) modulates human neutrophil functions in vitro. Incubation of freshly-separated human neutrophils with 10(-12)-10(-6)M (CKPV)(2) significantly inhibited activities relevant to the inflammatory reaction. Neutrophil migration toward the two chemoattractants interleukin 8 (IL-8) and N-formyl-methionyl-leucyl-phenylalanine (fMLP) was significantly inhibited by (CKPV)(2). (CKPV)(2) also inhibited reactive oxygen intermediate (ROI) production induced by phorbol 12-myristate 13-acetate (PMA), but not that induced by fMLP. Because these effects of (CKPV)(2) were abolished by the adenylyl cyclase inhibitor 2',5'-dideoxyadenosine (ddAdo), they appear to be cAMP-dependent. Finally, the peptide reduced lipopolysaccharide (LPS)-stimulated expression of TNF-alpha, interleukin-1beta (IL-1beta), interleukin-8 (IL-8), and intercellular adhesion molecule 1 (ICAM-1), as well as TNF-alpha protein release in cell supernatants. The data indicate that (CKPV)(2) modulates broad cAMP-dependent, anti-inflammatory pathways in human neutrophils.     

Cytokine and endothelial cell adhesion molecule expression in interleukin-10-deficient mice

The objectives of this study were to quantify cytokine mRNA levels and endothelial cell adhesion molecule message and protein expression in healthy wild-type and interleukin-10-deficient (IL-10(-/-)) mice that develop spontaneous and chronic colitis. We found that colonic message levels of IL-1, IL-6, tumor necrosis factor-alpha, interferon-gamma, lymphotoxin-beta, and transforming growth factor-beta were elevated in colitic mice 10- to 35-fold compared with their healthy wild-type controls. In addition, colonic message levels of intercellular adhesion molecule-1 (ICAM-1), vascular cell adhesion molecule-1 (VCAM-1), and mucosal addressin cell adhesion molecule-1 (MAdCAM-1) were found to be increased 10-, 5-, and 23-fold, respectively, in colitic IL-10(-/-) mice compared with their wild-type controls. Immunoradiolabeling as well as immunohistochemistry revealed large and significant increases in vascular surface expression of colonic ICAM-1, VCAM-1, and MAdCAM-1 in the mucosa as well as the submucosa of the colons of colitic mice. These data are consistent with the hypothesis that deletion of IL-10 results in the sustained production of proinflammatory cytokines, leading to the upregulation of adhesion molecules and infiltration of mononuclear and polymorphonuclear leukocytes into the cecal and colonic interstitium.