Tumor necrosis factor has positive and negative self regulatory feed back cycles centered around cAMP

Tumor Necrosis Factor-Alpha: Ally and Enemy in Protean Cutaneous Sceneries

Skin is the forestage for a series of many-sided functions of tumor necrosis factor-alpha (TNF-α), a proinflammatory cytokine with staggering versatility and sizable implications for tissue homeostasis, immune responses, angiogenesis, apoptosis, local and systemic inflammation. An aberrant TNF-α-mediated crosstalk has been linked to the pathogenesis of acute and chronic skin inflammatory diseases, and indeed, TNF-α dysregulation can contribute to the development and progression of psoriasis, vitiligo, local damage following exposition to ultraviolet light radiations, cutaneous lupus erythematosus, and acne vulgaris. Therapies that target TNF-α are conspicuously used in the treatment of different skin disorders, aiming to modulate the in vivo immune functions triggered by many cutaneous cells, including keratinocytes, mast cells, or Langerhans cells, and reduce inflammation taking place within the skin. Herein, we focus on the key relationships between TNF-α and distinct skin non-neoplastic inflammatory or physiologic conditions, showing that a natural induction of TNF-α may have a protective significance but that TNF-α overproduction may be harmful or even lethal. Many questions remain unraveled in the therapeutic practice, and caution should be exercised due to eventual backlashes exerted by TNF-α in maintaining skin health or in provoking skin disease.

Impact of Chronic Exposure to Arsenate through Drinking Water on the Intestinal Barrier

Chronic exposure to inorganic arsenic (As) [As(III) + As(V)], which affects millions of people, increases the incidence of some kinds of cancer and other noncarcinogenic pathologies. Although the oral pathway is the main source of exposure, in vivo studies conducted to verify the intestinal toxicity of this metalloid are scarce and are mainly focused on evaluating the toxicity of As(III). The aim of this study was to evaluate the effect of chronic exposure (6 months) of BALB/c mice to As(V) (15-60 mg/L) via drinking water on the different components of the intestinal barrier and to determine the possible mechanisms involved. The results show that chronic exposure to As(V) generates a situation of oxidative stress (increased lipid peroxidation and reactive species) and inflammation (increased contents of several proinflammatory cytokines and neutrophil infiltrations) in the intestinal tissues. There is also evidence of an altered expression of constituent proteins of the intercellular junctions (Cldn1, Cldn3, and Ocln) and the mucus layer (Muc2) and changes in the composition of the gut microbiota and the metabolism of short-chain fatty acids. All of these toxic effects eventually may lead to the disruption of the intestinal barrier, which shows an increased paracellular permeability. Moreover, signs of endotoxemia are observed in the serum of As(V)-treated animals (increases in lipopolysaccharide-binding protein LBP and the proinflammatory cytokine IL-1β). The data obtained suggest that chronic exposure to As(V) via drinking water affects the intestinal environment.

An Antioxidant Enzyme Therapeutic for Sepsis

Sepsis is a systemic inflammatory response syndrome caused by infections that may lead to organ dysfunction with high mortality. With the rapid increase in the aging population and antimicrobial resistance, developing therapeutics for the treatment of sepsis has been an unmet medical need. Excessive production of reactive oxygen species (ROS) during inflammation is associated with the occurrence of sepsis. We report herein a treatment for sepsis based on PEGylated catalase, which can effectively break down hydrogen peroxide, a key component of ROS that is chemically stable and able to diffuse around the tissues and form downstream ROS. PEGylated catalase can effectively regulate the cytokine production by activated leukocytes, suppress the elevated level of AST, ALT, TNF-α, and IL-6 in mice with induced sepsis, and significantly improve the survival rate.

Neuroprotective effects of roflumilast against quinolinic acid-induced rat model of Huntington's disease through inhibition of NF-κB mediated neuroinflammatory markers and activation of cAMP/CREB/BDNF signaling pathway

Huntington's disease (HD) is a progressive neurodegenerative and hyperkinetic movement disorder. Decreased activity of cAMP-responsive element-binding protein (CREB) is thought to contribute to the death of striatal medium spiny neurons in HD. The present study has been designed to explore the possible role of roflumilast against qunilonic acid (QA) induced neurotoxicity in rats intending to investigate whether it inhibits the neuroinflammatory response through activation of the cAMP/CREB/BDNF signaling pathway. QA was microinjected (200 nmol/2 µl, bilaterally) through the intrastriatal route in the stereotaxic apparatus. Roflumilast (0.5, 1, and 2 mg/kg, orally) once-daily treatment for 21 days significantly improved locomotor activity in actophotometer, motor coordination in rotarod, and impaired gait performance in narrow beam walk test. Moreover, roflumilast treatment significantly attenuated oxidative and nitrosative stress (p < 0.05) through attenuating lipid peroxidation nitrite concentration and enhancing reduced glutathione, superoxide dismutase, and catalase levels. Furthermore, roflumilast also significantly decreased elevated pro-inflammatory cytokines like TNF-α (p < 0.01), IL-6 (p < 0.01), IFN-γ (p < 0.05), NF-κB (p < 0.05) and significantly increased BDNF(p < 0.05) in the striatum and cortex of rat brain. The results further demonstrated that roflumilast effectively increased the gene expression of cAMP(p < 0.05), CREB(p < 0.05) and decreased the gene expression of PDE4 (p < 0.05) in qRT-PCR. These results conclusively depicted that roflumilast could be a potential candidate as an effective therapeutic agent in the management of HD through the cAMP/CREB/BDNF signaling pathway.

The phosphodiesterase 10 inhibitor papaverine exerts anti-inflammatory and neuroprotective effects via the PKA signaling pathway in neuroinflammation and Parkinson's disease mouse models

Background

Neuroinflammation plays a pivotal role in the pathogenesis of Parkinson’s disease (PD). Thus, the development of agents that can control neuroinflammation has been suggested as a promising therapeutic strategy for PD. In the present study, we investigated whether the phosphodiesterase (PDE) 10 inhibitor has anti-inflammatory and neuroprotective effects in neuroinflammation and PD mouse models.

Methods

Papaverine (PAP) was utilized as a selective inhibitor of PDE10. The effects of PAP on the expression of pro-inflammatory molecules were examined in lipopolysaccharide (LPS)–stimulated BV2 microglial cells by ELISA, RT-PCR, and Western blot analysis. The effects of PAP on transcription factors were analyzed by the electrophoretic mobility shift assay, the reporter gene assay, and Western blot analysis. Microglial activation and the expression of proinflammatory molecules were measured in the LPS- or MPTP-injected mouse brains by immunohistochemistry and RT-PCR analysis. The effect of PAP on dopaminergic neuronal cell death and neurotrophic factors were determined by immunohistochemistry and Western blot analysis. To assess mouse locomotor activity, rotarod and pole tests were performed in MPTP-injected mice.

Results

PAP inhibited the production of nitric oxide and proinflammatory cytokines in LPS-stimulated microglia by modulating various inflammatory signals. In addition, PAP elevated intracellular cAMP levels and CREB phosphorylation. Treatment with H89, a PKA inhibitor, reversed the anti-inflammatory effects of PAP, suggesting the critical role of PKA signaling in the anti-inflammatory effects of PAP. We verified the anti-inflammatory effects of PAP in the brains of mice with LPS-induced systemic inflammation. PAP suppressed microglial activation and proinflammatory gene expression in the brains of these mice, and these effects were reversed by H89 treatment. We further examined the effects of PAP on MPTP-injected PD model mice. MPTP-induced dopaminergic neuronal cell death and impaired locomotor activity were recovered by PAP. In addition, PAP suppressed microglial activation and proinflammatory mediators in the brains of MPTP-injected mice.

Conclusions

PAP has strong anti-inflammatory and neuroprotective effects and thus may be a potential candidate for treating neuroinflammatory disorders such as PD.

Gambir Extract (Uncaria Gambir) Decreases Inflammatory Response and Increases Gastric Mucosal Integrity in Wistar Rats - Model Gastritis

BACKGROUND:

Uncaria gambir (local name: gambir) is a plant native to Sumatera, Malaya and Borneo. This plant is potential as local wisdom for therapeutics. In Sumatera, gambir was used as a traditional treatment for fever, diarrhoea, diabetics and wound healing.

AIM:

To explore the efficacy of gambir extract on TNF alpha level, prostaglandin E2 level, lesson area, body weight, lipid profile and leptin level in Wistar rat-model gastritis.

METHODS:

This study was an experimental study, with a pre-post-test control group design. The subjects in this study were 30 male rats, 8 weeks old, weight 150-200 gram. Rats were administered with gambir extract at the dose of 20, 40 and 80 mg/kg BW/day for 3 days. Gambir was extracted by maceration methods. Statistical analysis was performed by SPSS 18.

RESULTS:

Gambir extract at the dose of 80 mg/kg BW exhibited the highest efficacy in reducing TNF alpha level, lesion area and increasing prostaglandin E2 level compared to gambir extract at doses of 20 mg/kg BW, 400 mg/kg BW, negative control, and positive control.

CONCLUSION:

Gambir extract was effective in reducing TNF alpha level, lesson area, and increasing prostaglandin E2 level in Wistar rat-model gastritis.

Paths for Improving Bevacizumab Available in 2018: The ADZT Regimen for Better Glioblastoma Treatment

During glioblastoma treatment, the pharmaceutical monoclonal antibody to vascular endothelial growth factor A, bevacizumab, has improved the quality of life and delayed progression for several months, but has not (or only marginally) prolonged overall survival. In 2017, several dramatic research papers appeared that are crucial to our understanding of glioblastoma vis-a-vis the mode of action of bevacizumab. As a consequence of these papers, a new, potentially more effective treatment protocol can be built around bevacizumab. This is the ADZT regimen, where four old drugs are added to bevacizumab. These four drugs are apremilast, marketed to treat psoriasis, dapsone, marketed to treat Hansen’s disease, zonisamide, marketed to treat seizures, and telmisartan, marketed to treat hypertension. The ancillary attributes of each of these drugs have been shown to augment bevacizumab. This paper details the research data supporting this contention. Phase three testing of AZDT addition to bevacizumab is required to establish safety and effectiveness before general use.

Blocking epithelial-to-mesenchymal transition in glioblastoma with a sextet of repurposed drugs: the EIS regimen

This paper outlines a treatment protocol to run alongside of standard current treatment of glioblastoma- resection, temozolomide and radiation. The epithelial to mesenchymal transition (EMT) inhibiting sextet, EIS Regimen, uses the ancillary attributes of six older medicines to impede EMT during glioblastoma. EMT is an actively motile, therapy-resisting, low proliferation, transient state that is an integral feature of cancers’ lethality generally and of glioblastoma specifically. It is believed to be during the EMT state that glioblastoma’s centrifugal migration occurs. EMT is also a feature of untreated glioblastoma but is enhanced by chemotherapy, by radiation and by surgical trauma. EIS Regimen uses the antifungal drug itraconazole to block Hedgehog signaling, the antidiabetes drug metformin to block AMP kinase (AMPK), the analgesic drug naproxen to block Rac1, the anti-fibrosis drug pirfenidone to block transforming growth factor-beta (TGF-beta), the psychiatric drug quetiapine to block receptor activator NFkB ligand (RANKL) and the antibiotic rifampin to block Wnt- all by their previously established ancillary attributes. All these systems have been identified as triggers of EMT and worthy targets to inhibit. The EIS Regimen drugs have a good safety profile when used individually. They are not expected to have any new side effects when combined. Further studies of the EIS Regimen are needed.

Suppression of Lipopolysaccharide-Induced Neuroinflammation by Morin via MAPK, PI3K/Akt, and PKA/HO-1 Signaling Pathway Modulation

Morin is a flavonoid isolated from certain fruits and Chinese herbs and is known to possess various medicinal properties. In this study, we investigated the anti-inflammatory effects of morin on lipopolysaccharide (LPS)-induced microglial activation, both in vitro and in vivo. We found that morin inhibited inducible nitric oxide synthase (iNOS) and pro-inflammatory cytokines in LPS-stimulated BV2 microglial cells. Furthermore, morin suppressed the microglial activation and cytokine expression in the brains of LPS-stimulated mice. Subsequent mechanistic studies revealed that morin inhibited the action of LPS-activated mitogen-activated protein kinases (MAPKs), protein kinase B (Akt) phosphorylation, nuclear factor-κB (NF-κB), and activating protein-1 (AP-1). Further, the phosphorylation and DNA binding activity of cAMP responsive element binding protein (CREB) was enhanced by morin. Moreover, morin suppressed the LPS-induced expression of nicotinamide adenine dinucleotide phosphate (NADPH) oxidase subunits, while it increased heme oxygenase-1 (HO-1) expression and nuclear factor erythroid 2-related factor 2 (Nrf2) activation. Therefore, our data suggest that morin exerts anti-inflammatory effects in LPS-stimulated microglia by downregulating MAPK and phosphatidylinositol 3-kinase (PI3K)/Akt signaling pathways while upregulating protein kinase A (PKA)/CREB and Nrf2/HO-1 signaling pathways.

Exogenous ceramide-1-phosphate (C1P) and phospho-ceramide analogue-1 (PCERA-1) regulate key macrophage activities via distinct receptors

Inflammation is an ensemble of tightly regulated steps, in which macrophages play an essential role. Previous reports showed that the natural sphingolipid ceramide 1-phosphate (C1P) stimulates macrophages migration, while the synthetic C1P mimic, phospho-ceramide analogue-1 (PCERA-1), suppresses production of the key pro-inflammatory cytokine TNFα and amplifies production of the key anti-inflammatory cytokine IL-10 in LPS-stimulated macrophages, via one or more unidentified G-protein coupled receptors. We show that C1P stimulated RAW264.7 macrophages migration via the NFκB pathway and MCP-1 induction, while PCERA-1 neither mimicked nor antagonized these activities. Conversely, PCERA-1 synergistically elevated LPS-dependent IL-10 expression in RAW264.7 macrophages via the cAMP-PKA-CREB signaling pathway, while C1P neither mimicked nor antagonized these activities. Interestingly, both compounds have the capacity to additively inhibit TNFα secretion; PCERA-1, but not C1P, suppressed LPS-induced TNFα expression in macrophages in a CREB-dependent manner, while C1P, but not PCERA-1, directly inhibited recombinant TNFα converting enzyme (TACE). Finally, PCERA-1 failed to interfere with binding of C1P to either the cell surface receptor or to TACE. These results thus indicate that the natural sphingolipid C1P and its synthetic analog PCERA-1 bind and activate distinct receptors expressed in RAW264.7 macrophages. Identification of these receptors will be instrumental for elucidation of novel activities of extra-cellular sphingolipids, and may pave the way for the design of new sphingolipid mimics for the treatment of inflammatory diseases, and pathologies which depend on cell migration, as in metastatic tumors.

Fingolimod (FTY720) enhances hippocampal synaptic plasticity and memory in Huntington's disease by preventing p75NTR up-regulation and astrocyte-mediated inflammation

Huntington's disease (HD) is a hereditary neurodegenerative disorder characterized by motor and cognitive impairments, involving striatum, cortex and hippocampus. Synaptic and memory dysfunction in HD mouse models have been related to low levels of brain-derived neurotrophic factor (BDNF) and imbalance between TrkB and p75(NTR) receptors. In addition, astrocyte over-activation has also been suggested to contribute to HD cognitive deficits. Fingolimod (FTY720), a modulator of sphingosine-1 phosphate (S1P) receptors, has been shown to increase BDNF levels and to reduce astrogliosis, proving its potential to regulate trophic support and inflammatory response. In this view, we have investigated whether FTY720 improves synaptic plasticity and memory in the R6/1 mouse model of HD, through regulation of BDNF signaling and astroglial reactivity. Chronic administration of FTY720 from pre-symptomatic stages ameliorated long-term memory deficits and dendritic spine loss in CA1 hippocampal neurons from R6/1 mice. Furthermore, FTY720 delivery prevented astrogliosis and over-activation of nuclear factor kappa beta (NF-κB) signaling in the R6/1 hippocampus, reducing tumor necrosis factor alpha (TNFα) and induced nitric oxide synthase (iNOS) levels. TNFα decrease correlated with the normalization of p75(NTR) expression in the hippocampus of FTY720-treated R6/1 mice, thus preventing p75(NTR)/TrkB imbalance. In addition, FTY720 increased cAMP levels and promoted phosphorylation of CREB and RhoA in the hippocampus of R6/1 mice, further supporting its role in the enhancement of synaptic plasticity. Our findings provide new insights into the mechanism of action of FTY720 and reveal a novel therapeutic strategy to treat memory deficits in HD.

Aloe vera attenuated gastric injury on indomethacin-induced gastropathy in rats

AIM: To evaluate the protective effects of Aloe vera on gastric injury in rats with indomethacin (IMN)-induced gastropathy.

METHODS: Male Sprague-Dawley rats were randomly divided into three groups. Group 1 (control, n = 6) was given distilled water (DW) orally. Group 2 (IMN, n = 6) was given oral IMN (150 mg/kg) dissolved in 5% sodium bicarbonate (NaHCO₃^-) at time 0 and 4 h. Group 3 (Aloe vera-treated, n = 6) was given oral Aloe vera (150 mg/kg) dissolved in DW and IMN at time 0 and 4 h. Eight hours later, the stomach was removed to determine gastric malondialdehyde (MDA), the number of interleukin (IL)-18 positive stained cells (%) by immunohistochemistry, and for histopathological examination. Then, the serum was collected to determine tumor necrosis factor (TNF)-α and cytokine-induced neutrophil chemoattractant (CINC)-1 by sandwich enzyme linked immunosorbent assay method.

RESULTS: In the IMN group, serum TNF-α, CINC-1 and gastric MDA were significantly increased when compared to the control group (27.78 ± 1.52 pg/mL vs 85.07 ± 49.11 pg/mL, P = 0.009; 104.55 ± 45.80 pg/mL vs 1054.70 ± 20.38 pg/mL, and 1.74 ± 0.21 nmol/mg vs 9.36 ± 1.07 nmol/mg protein, P = 0.000, respectively). The mean level of TNF-α, CINC-1 and gastric MDA in the Aloe vera-treated group were improved as compared with the IMN group (85.07 ± 49.11 pg/mL vs 35.19 ± 1.61 pg/mL, P = 0.021; 1054.70 ± 20.38 pg/mL vs 813.56 ± 239.04 pg/mL, P = 0.025; and 9.36 ± 1.07 nmol/mg vs 2.67 ± 0.64 nmol/mg protein, P = 0.000, respectively). The number of IL-18 positive stained cells (%) in the gastric epithelial cells of the IMN group was significantly higher than the control group (5.01% ± 3.73% vs 30.67% ± 2.03%, P = 0.000, respectively). In contrast, Aloe vera treatment decreased the number of IL-18 positive stained cells (%) significantly when compared with the IMN group (30.67% ± 2.03% vs 13.21% ± 1.10%, P = 0.000, respectively). Most rats in the IMN group developed moderate to severe gastric inflammation and erosions. The gastric erosions and neutrophil infiltration scores were significantly reduced in the Aloe vera-treated group.

CONCLUSION: Aloe vera attenuated IMN-induced gastropathy in rats by the reduction of oxidative stress, inflammation, and improvement of gastric histopathology.

Pretreatment with antiasthmatic drug ibudilast ameliorates Aβ 1-42-induced memory impairment and neurotoxicity in mice

Amyloid-β peptide (Aβ) is thought to be associated with the progressive neuronal death observed in Alzheimer's disease (AD). However, effective neuroprotective approaches against Aβ neurotoxicity are unavailable. Here, we investigated possible preventive effects of ibudilast, as a pharmacologic phosphodiesterase inhibitor, currently used for treatment of inflammatory diseases such as asthma, on Aβ 1-42-induced neuroinflammatory, apoptotic responses and memory impairment. We found that pretreatment with ibudilast (4 or 12 mg/kg, i.p.) significantly ameliorated impaired spatial learning and memory in intracerebroventricularly (ICV) Aβ 1-42-injected mice, as evidenced by decrease in escape latency during acquisition trials and increase in exploratory activities in the probe trial in Morris water maze (MWM) task, and by increase in the number of correct choices and decrease in latency to enter the shock-free compartment in Y-maze test. Further study showed that ibudilast prevented generation of pro-inflammatory cytokines such as NF-κB p65 and TNF-α as well as pro-apoptotic molecule caspase-3 activation and anti-apoptotic protein Bcl-2 downregulation in both hippocampus and cortex of ICV Aβ 1-42-injected mice. Taken together, our findings suggest that ibudilast has preventive effects on Aβ-induced cognitive impairment via inhibiting neuroinflammatory and apoptotic responses.

Hydrogen gas presents a promising therapeutic strategy for sepsis

Sepsis is characterized by a severe inflammatory response to infection. It remains a major cause of morbidity and mortality in critically ill patients despite developments in monitoring devices, diagnostic tools, and new therapeutic options. Recently, some studies have found that molecular hydrogen is a new therapeutic gas. Our studies have found that hydrogen gas can improve the survival and organ damage in mice and rats with cecal ligation and puncture, zymosan, and lipopolysaccharide-induced sepsis. The mechanisms are associated with the regulation of oxidative stress, inflammatory response, and apoptosis, which might be through NF- κ B and Nrf2/HO-1 signaling pathway. In this paper, we summarized the progress of hydrogen treatment in sepsis.

Novel therapeutic targets for sepsis: regulation of exaggerated inflammatory responses

Sepsis is a devastating and complex syndrome and continues to be a major cause of morbidity and mortality among critically ill patients at the surgical intensive care unit setting in the United States. The occurrence of sepsis and septic shock has increased significantly over the past two decades. Despite of highly dedicated basic research and numerous clinical trials, remarkable progress has not been made in the development of novel and effective therapeutics. The sepsis-induced physiologic derangements are due largely to the host responses to the invading microorganism in contrast to the direct effects of the microorganism itself. Sepsis, the systemic inflammatory response to infection, is marked by dysregulated production of pro-inflammatory cytokines. Although pro-inflammatory cytokine production is normally indispensable to protect against pathogens and promote tissue repair, the dysregulated and prolonged production of these cytokines can trigger a systemic inflammatory cascade mediated by chemokines, vasoactive amines, the complement and coagulation system, and reactive oxygen species (ROS), amongst others. These mediators collectively lead to multiple organ failure, and ultimately to death. In this regard, the role of inflammation in the pathophysiology of sepsis, although still incompletely understood, is clearly critical. Recent findings resulting from vigorous investigations have contributed to delineate various novel directions of sepsis therapeutics. Among these, this review article is focused on new promising mechanisms and concepts that could have a key role in anti-inflammatory strategies against sepsis, including 1) "inflammasome": a multiprotein complex that activates caspase-1; 2) "the cholinergic anti-inflammatory pathway": the efferent arm of the vagus nerve-mediated, brain-to-immune reflex; 3) "stem cells": unspecialized and undifferentiated precursor cells with the capacity for self-renewal and potential to change into cells of multiple lineages; 4) "milk fat globule-EGF factor VIII (MFG-E8)": a bridging molecule between apoptotic cells and phagocytes, which promotes phagocytosis of apoptotic cells.

Imiquimod: the biochemical mechanisms of immunomodulatory and anti-inflammatory activity

Imidazoquinolins represent a new group of compounds that recently entered into clinical practice as anti-tumor and anti-viral immune modulators. They are low molecular weight synthetic guanosine-like molecules. Although imiquimod, the most widely used imidazoquinolin, is recommended for the treatment of several forms of skin cancer and papillomas, the molecular mechanisms of its action are not fully understood. In particular, imiquimod has been characterized as a specific agonist of Toll-like receptor 7 (TLR7) and is widely used in this capacity in a large number of experimental studies and clinical trials. However, detailed analysis of the published data with the use of imiquimod, suggests that its biological activity can not be explained only by interaction with TLR7. There are indications of a direct interaction of imiquimod with adenosine receptors and other molecules that regulate the synthesis of cyclic adenosine monophosphate. A detailed understanding of the biochemical basis of imiquimod immunomodulating and antitumor effect will increase its clinical effectiveness and accelerate the development of new drugs with similar but improved medical properties. This review summarizes the published data concerning the effects of imiquimod on a variety of intracellular biochemical processes and signaling pathways.

The phosphodiesterase-4 inhibitor rolipram reverses Aβ-induced cognitive impairment and neuroinflammatory and apoptotic responses in rats

β-amyloid (Aβ) peptides play an important role in cognition deficits, neuroinflammation, and apoptosis observed in Alzheimer's disease (AD). Activation of cyclic AMP (cAMP) signalling enhances memory and inhibits inflammatory and apoptotic responses. However, it is not known whether inhibition of phosphodiesterase-4 (PDE4), a critical controller of intracellular cAMP concentrations, affects AD-associated neuroinflammatory and apoptotic responses and whether these responses contribute to deficits of memory mediated by cAMP signalling. We addressed these issues using memory tests and neurochemical measures. Specifically, rats microinfused with aggregated Aβ25-35 (10 μg/side) into bilateral CA1 subregions displayed deficits in learning ability and memory, as evidenced by decreases in escape latency during acquisition trials and exploratory activities in the probe trial in the water-maze task and 24-h retention in the passive avoidance test. These effects were reversed by rolipram (0.1, 0.25 and 0.5 mg/kg.d i.p.), a prototypic PDE4 inhibitor, in a dose-dependent manner. Interestingly, Aβ25-35-treated rats also displayed decreases in expression of phosphorylated cAMP response-element binding protein (pCREB) and Bcl-2, but increases in expression of NF-κB p65 and Bax in the hippocampus; these effects were also reversed by rolipram in a dose-dependent manner. Similar neurochemical results were observed by replacing Aβ25-35 with Aβ1-42, a full-length amyloid peptide that quickly forms toxic oligomers. These results suggest that PDE4 inhibitors such as rolipram may reverse Aβ-induced memory deficits at least in part via the attenuation of neuronal inflammation and apoptosis mediated by cAMP/CREB signalling. PDE4 could be a target for treatment of memory loss associated with AD.

The glial cell modulators, ibudilast and its amino analog, AV1013, attenuate methamphetamine locomotor activity and its sensitization in mice

Over 800,000 Americans abuse the psychomotor stimulant, methamphetamine, yet its abuse is without an approved medication. Methamphetamine induces hypermotor activity, and sensitization to this effect is suggested to represent aspects of the addiction process. Methamphetamine's regulation of 3'-5'-cyclic adenosine monophosphate (cAMP) levels may be partially responsible for its behavioral effects, and compounds that inhibit phosphodiesterase (PDE), the enzyme that degrades cAMP, can alter methamphetamine-induced behaviors. Methamphetamine also activates glial cells and causes a subsequent increase in pro-inflammatory cytokine levels. Modulation of glial cell activation is associated with changes in behavioral responses, and substances that oppose inflammatory activity can attenuate drug-induced behaviors. Ibudilast (aka AV411; 3-isobutyryl-2-isopropylpyrazolo-[1,5-a]pyridine), inhibits both PDE and glial pro-inflammatory activity. Ibudilast's amino analog, AV1013, modulates similar glial targets but negligibly inhibits PDE. The present study determined whether ibudilast and AV1013 would attenuate methamphetamine-induced locomotor activity and its sensitization in C57BL/6J mice. Mice were treated b.i.d. with ibudilast (1.8-13 mg/kg), AV1013 (10-56 mg/kg) or their vehicles intraperitoneally for 7 days, beginning 48 h before 5 days of daily 1-h locomotor activity tests. Each test was initiated by either a methamphetamine (3 mg/kg) or a saline injection. Ibudilast significantly (P<0.05) reduced the acute, chronic, and sensitization effects of methamphetamine's locomotor activity without significantly affecting activity by itself. AV1013 had similar anti-methamphetamine effects, suggesting that glial cell activity, by itself, can modulate methamphetamine's effects and perhaps serve as a medication target for its abuse.

Phosphodiesterase-4 inhibition alters gene expression and improves isoniazid-mediated clearance of Mycobacterium tuberculosis in rabbit lungs

Tuberculosis (TB) treatment is hampered by the long duration of antibiotic therapy required to achieve cure. This indolent response has been partly attributed to the ability of subpopulations of less metabolically active Mycobacterium tuberculosis (Mtb) to withstand killing by current anti-TB drugs. We have used immune modulation with a phosphodiesterase-4 (PDE4) inhibitor, CC-3052, that reduces tumor necrosis factor alpha (TNF-α) production by increasing intracellular cAMP in macrophages, to examine the crosstalk between host and pathogen in rabbits with pulmonary TB during treatment with isoniazid (INH). Based on DNA microarray, changes in host gene expression during CC-3052 treatment of Mtb infected rabbits support a link between PDE4 inhibition and specific down-regulation of the innate immune response. The overall pattern of host gene expression in the lungs of infected rabbits treated with CC-3052, compared to untreated rabbits, was similar to that described in vitro in resting Mtb infected macrophages, suggesting suboptimal macrophage activation. These alterations in host immunity were associated with corresponding down-regulation of a number of Mtb genes that have been associated with a metabolic shift towards dormancy. Moreover, treatment with CC-3052 and INH resulted in reduced expression of those genes associated with the bacterial response to INH. Importantly, CC-3052 treatment of infected rabbits was associated with reduced ability of Mtb to withstand INH killing, shown by improved bacillary clearance, from the lungs of co-treated animals compared to rabbits treated with INH alone. The results of our study suggest that changes in Mtb gene expression, in response to changes in the host immune response, can alter the responsiveness of the bacteria to antimicrobial agents. These findings provide a basis for exploring the potential use of adjunctive immune modulation with PDE4 inhibitors to enhance the efficacy of existing anti-TB treatment.

Tuberculosis (TB) caused by Mycobacterium tuberculosis (Mtb) is a leading infectious cause of morbidity and mortality. Although current antibiotic regimens can cure TB, treatment requires at least six months for completion. Recent studies indicate that bacteria in a less metabolically active state are less responsive to antibiotic killing and suggest that this may partly explain the long duration required for TB treatment. In this study, using a rabbit model of pulmonary TB, we show that immune modulation of Mtb infected animals with CC-3052, a phosphodiesterase-4 (PDE4) inhibitor that reduces tumor necrosis factor alpha (TNF-α) production by increasing intracellular cAMP levels, resulted in the down-regulation of host genes involved in the innate immune response. Bacteria from the lungs of CC-3052 treated rabbits displayed differential expression of those genes associated with stress responses. In addition, co-treatment of INH with CC-3052 abolished the INH-induced Mtb gene expression in the infected rabbits. Importantly, bacillary clearance from the lungs of rabbits co-treated with CC-3052 and INH was improved over that in animals treated with INH alone. The results of this study provide a basis for novel use of immune modulation to improve the efficacy of antibiotic therapy and to shorten the duration of TB treatment.

Glioblastoma chemotherapy adjunct via potent serotonin receptor-7 inhibition using currently marketed high-affinity antipsychotic medicines

Glioblastoma treatment as now constituted offers increased survival measured in months over untreated patients. Because glioblastomas are active in synthesizing a bewildering variety of growth factors, a systematic approach to inhibiting these is being undertaken as treatment adjunct. The serotonin 7 receptor is commonly overexpressed in glioblastoma. Research documentation showing agonists at serotonin receptor 7 cause increased extracellular regulated kinase 1/2 activation, increased interleukin-6 synthesis, increased signal transducer and activator of transcription-3 activation, increased resistance to apoptosis and other growth enhancing changes in glioblastoma is reviewed in this paper. Because three drugs in wide use to treat thought disorders - paliperidone, pimozide and risperidone - are also potent and well-tolerated inhibitors at serotonin receptor 7, these drugs should be studied for growth factor deprivation in an adjunctive role in glioblastoma treatment.

Anti-inflammatory mechanism of ginsenoside Rh1 in lipopolysaccharide-stimulated microglia: critical role of the protein kinase A pathway and hemeoxygenase-1 expression

Microglia activation plays a pivotal role in neurodegenerative diseases, and thus controlling microglial activation has been suggested as a promising therapeutic strategy for neurodegenerative diseases. In the present study, we showed that ginsenoside Rh1 inhibited inducible nitric oxide synthase, cyclooxygenase-2, and pro-inflammatory cytokine expression in lipopolysaccharide (LPS)-stimulated microglia, while Rh1 increased anti-inflammatory IL-10 and hemeoxygenase-1 (HO-1) expression. Suppression of microglial activation by Rh1 was also observed in the mouse brain following treatment with LPS. Subsequent mechanistic studies revealed that Rh1 inhibited LPS-induced MAPK phosphorylation and nuclear factor-κB (NF-κB)-mediated transcription without affecting NF-κB DNA binding. As the increase of pCREB (cAMP responsive element-binding protein) is known to result in suppression of NF-κB-mediated transcription, we examined whether Rh1 increased pCREB levels. As expected, Rh1 increased pCREB, which was shown to be related to the anti-inflammatory effect of Rh1 because pre-treatment with protein kinase A inhibitors attenuated the Rh1-mediated inhibition of nitric oxide production and the up-regulation of IL-10 and HO-1. Furthermore, treatment of HO-1 shRNA attenuated Rh1-mediated inhibition of nitric oxide and reactive oxygen species production. Through this study, we have demonstrated that protein kinase A and its downstream effector, HO-1, play a critical role in the anti-inflammatory mechanism of Rh1 by modulating pro- and anti-inflammatory molecules in activated microglia.

Mechanisms of non-opioid analgesics beyond cyclooxygenase enzyme inhibition

Non-opioid analgesics including both selective and non-selective cyclooxygenase (COX) inhibitors and acetaminophen are the most widely used treatments for pain. Inhibition of COX is thought to be largely responsible for both the therapeutic and adverse effects of this class of drugs. Accumulating evidence over the past two decades has demonstrated effects of non-opioids beyond the inhibition of COX and prostaglandin synthesis that might also explain their therapeutic and adverse effects. These include their interaction with endocannabinoids, nitric oxide, monoaminergic, and cholinergic systems. Moreover, the recent development of microarray technology that allows the study of human gene expression suggests multiple pathways that may be related to the analgesic and anti-inflammatory effects of non-opioids. The present review will discuss the multiple actions of non-opioids and their interactions with these systems during inflammation and pain, suggesting that COX inhibition is an incomplete explanation for the actions of non-opioids and proposes the involvement of multiple selective targets for their analgesic, as well as, their adverse effects.

The ceramide-1-phosphate analogue PCERA-1 modulates tumour necrosis factor-alpha and interleukin-10 production in macrophages via the cAMP-PKA-CREB pathway in a GTP-dependent manner

The synthetic phospho-ceramide analogue-1 (PCERA-1) down-regulates production of the pro-inflammatory cytokine tumour necrosis factor-alpha (TNF-alpha) and up-regulates production of the anti-inflammatory cytokine interleukin-10 (IL-10) in lipopolysaccharide (LPS) -stimulated macrophages. We have previously reported that PCERA-1 increases cyclic adenosine monophosphate (cAMP) levels. The objective of this study was to delineate the signalling pathway leading from PCERA-1 via cAMP to modulation of TNF-alpha and IL-10 production. We show here that PCERA-1 elevates intra-cellular cAMP level in a guanosine triphosphate-dependent manner in RAW264.7 macrophages. The cell-permeable dibutyryl cAMP was able to mimic the effects of PCERA-1 on cytokine production, whereas 8-chloro-phenylthio-methyladenosine-cAMP, which specifically activates the exchange protein directly activated by cAMP (EPAC) but not protein kinase A (PKA), failed to mimic PCERA-1 activities. Consistently, the PKA inhibitor H89 efficiently blocked PCERA-1-driven cytokine modulation as well as PCERA-1-stimulated phosphorylation of cAMP response element binding protein (CREB) on Ser-133. Finally, PCERA-1 activated cAMP-responsive transcription of a luciferase reporter, in synergism with the phosphodiesterase (PDE)-4 inhibitor rolipram. Our results suggest that PCERA-1 activates a G(s) protein-coupled receptor, leading to elevation of cAMP, which acts via the PKA-CREB pathway to promote TNF-alpha suppression and IL-10 induction in LPS-stimulated macrophages. Identification of the PCERA-1 receptor is expected to set up a new target for development of novel anti-inflammatory drugs.

A ceramide-1-phosphate analogue, PCERA-1, simultaneously suppresses tumour necrosis factor-alpha and induces interleukin-10 production in activated macrophages

Tight regulation of the production of the key pro-inflammatory cytokine tumour necrosis factor-alpha (TNF-alpha) is essential for the prevention of chronic inflammatory diseases. In vivo administration of a synthetic phospholipid, named hereafter phospho-ceramide analogue-1 (PCERA-1), was previously found to suppress lipopolysaccharide (LPS)-induced TNF-alpha blood levels. We therefore investigated the in vitro anti-inflammatory effects of PCERA-1. Here, we show that extracellular PCERA-1 potently suppresses production of the pro-inflammatory cytokine TNF-alpha in RAW264.7 macrophages, and in addition, independently and reciprocally regulates the production of the anti-inflammatory cytokine interleukin-10 (IL-10). Specificity is demonstrated by the inability of the phospholipids ceramide-1-phosphate (C1P), sphingosine-1-phosphate (S1P) and lysophosphatidic acid (LPA) to perform these activities. Similar TNF-alpha suppression and IL-10 induction by PCERA-1 were observed in macrophages when activated by Toll-like receptor 4 (TLR4), TLR2 and TLR7 agonists. Regulation of cytokine production is demonstrated at the mRNA and protein levels. Finally, we show that, while PCERA-1 does not block activation of nuclear factor (NF)-kappaB and mitogen-activated protein kinases by LPS, it elevates the intracellular cAMP level. In conclusion, the anti-inflammatory activity of PCERA-1 seems to be mediated by a cell membrane receptor, upstream of cAMP production, and eventually TNF-alpha suppression and IL-10 induction. Thus, identification of the PCERA-1 receptor may provide new pharmacological means to block inflammation.

Synergistic IL-10 induction by LPS and the ceramide-1-phosphate analog PCERA-1 is mediated by the cAMP and p38 MAP kinase pathways

Expression of the anti-inflammatory cytokine IL-10 can be induced either by TLR agonists such as lipopolysaccharide (LPS), or by various endogenous stimuli, in particular those acting via a cAMP-dependent signaling pathway. We have previously reported that the synthetic phospho-ceramide analogue-1 (PCERA-1) increases cAMP level and subsequently down-regulates production of TNFalpha and up-regulates production of IL-10 in LPS-stimulated macrophages. The objective of this study was to determine the mechanism of activity of PCERA-1 and the role of cAMP in LPS-induced IL-10 production. We show here that PCERA-1 induces IL-10 production in synergism with various TLR agonists in mouse RAW264.7 macrophages. Cooperativity is evident both at the mRNA and protein levels. IL-10 production by LPS and PCERA-1 is mediated by the cAMP pathway and by the p38 MAP kinase. Phosphorylation of p38 is cooperatively accomplished by LPS and PCERA-1 or other cAMP inducers. Furthermore, the activity of PCERA-1 can be partially mimicked by a cell-permeable analog of cAMP, and blocked by the protein kinase A (PKA) inhibitor H89. Finally, in the absence of PCERA-1, the residual IL-10 induction by LPS depends on the basal cAMP level as it can be largely elevated by the phosphodiesterase (PDE)-4 inhibitor rolipram. Our results thus indicate that IL-10 induction by LPS critically depends on basal cAMP level, and that a co-stimulus by a TLR agonist and a cAMP-elevating agent results in synergistic PKA-dependent and p38-dependent IL-10 production.

Fractional excretion of tumor necrosis factor-alpha in women with severe preeclampsia

OBJECTIVE

Proinflammatory cytokines of placental or systemic origin are thought to play a central role in the pathophysiology of preeclampsia. We sought to estimate the fractional excretion of tumor necrosis factor (TNF)-alpha in relationship to proteinuria in women with severe preeclampsia.

METHODS

In a cross-sectional study, we evaluated the serum and urine levels of TNF-alpha in 45 women diagnosed with severe preeclampsia (mean+/-standard error of the mean, gestational age 29.1+/-0.5 weeks). Forty-five healthy pregnant women matched for parity, maternal age, and gestational age at recruitment (30.1+/-0.4 weeks) made up the control group. Urinary concentrations were normalized to creatinine. The fractional excretion of TNF-alpha was interpreted in relationship to that of total proteins and soluble fms-like tyrosine kinase-1 (sFlt-1).

RESULTS

We found that the women with preeclampsia had significantly higher serum TNF-alpha concentrations compared with the women in the control group (mean+/-standard error of the mean, preeclampsia: 1.39+/-0.09 versus control: 0.93+/-0.07 pg/mL, P<.001). In contrast, urinary levels of TNF-alpha were significantly decreased in the women with preeclampsia compared with the healthy women (median [interquartile range], preeclampsia: 0.26 [0.10-0.91] versus control: 0.58 [0.21-1.29] pg/mg creatinine, P=.003), even though the hypertensive women had higher levels of proteinuria. In contrast to sFlt-1, urinary TNF-alpha did not correlate with the degree of proteinuria. Additionally, in preeclampsia, the fractional excretion of TNF-alpha was significantly lower (preeclampsia: 1.92% [0.46-4.20] versus control: 7.2% [2.44-12.07], P<.001).

CONCLUSION

The fractional excretion of TNF-alpha is significantly reduced in women with severe preeclampsia despite proteinuria. The decreased clearance and altered renal excretion of this cytokine may contribute to the exaggerated inflammatory response observed in preeclampsia.

LEVEL OF EVIDENCE

II.

Melanoma inhibition by cyclooxygenase inhibitors: role of interleukin-6 suppression, a putative mechanism of action, and clinical implications

Melanoma progression is often associated with supranormal levels of interleukin-6 (IL-6). Il-6 is an important growth factor for many cases of melanoma. A recent case report by Lejeune et al. [Melanoma Res 2006;16:263-265] of remission of an advanced melanoma during treatment with the cyclooxygenase, (COX) inhibitor rofecoxib can be explained by rofcoxib-mediated lowering of tumor-produced Il-6. Several examples of rofecoxib's ability to lower Il-6 in humans have been published recently in other settings, and many reports indicate that other commonly used COX inhibitors like aspirin, diclofenac, etodolac, indomethacin, naproxen, and many others, also lower Il-6 in humans. These studies are reviewed. The likely mechanism of COX inhibition leading to Il-6 lowering is due to the tendency for Il-6 levels to be controlled by intracellular cyclic adenosine monophosphate (cAMP). Adenylate cyclase is the rate-limiting enzyme in cAMP synthesis. Because adenylate cyclase activity is allosterically enhanced when it binds prostaglandin E, the latter increases Il-6. COX inhibition lowers prostaglandin E levels. This lowers intracellular cAMP levels. Lower cAMP results in lower Il-6 synthesis, lower levels of a required growth factor. Controlled studies are needed to define the role of COX inhibitors in melanoma treatment.

Simvastatin stimulates macrophage interleukin-1β secretion through an isoprenylation-dependent mechanism

Statin treatment inhibits oxidized lipoprotein-induced intracellular lipid accumulation (foam cell formation) and reduces plasma levels of inflammatory markers such as interleukin-1beta (IL-1beta). The aim of the present study was to determine if simvastatin affected lipid accumulation in macrophages incubated with aggregated low density lipoproteins (AgLDL) and whether simvastatin had a direct effect on cytokine secretion from macrophages. Simvastatin treatment did not inhibit AgLDL-induced macrophage lipid accumulation, but significantly increased the secretion of IL-1beta and IL-8 from macrophages, whilst inhibiting the secretion of tumor necrosis factor-alpha (TNF-alpha) and having no significant effect on IL-6 secretion. Increased macrophage lipid content did not block statin-induced IL-1beta and IL-8 secretion. Simvastatin-stimulated IL-1beta secretion from macrophages was inhibited by isoprenoids. We therefore hypothesized that simvastatin stimulated IL-1beta secretion by affecting isoprenylation-dependent signaling pathways. Another possible mechanism for affecting such signaling is to impair isoprenoid transfer protein activity with specific inhibitors such as GGTI-297 and FTInhI. This treatment resulted in strong stimulation of IL-1beta secretion that was further enhanced when exogenous IL-1beta was present at the beginning of treatment. These data suggest an isoprenylation-dependent negative-feedback loop for macrophage IL-1beta secretion that is inhibited by statin treatment.

Review of evidence that posttransplantation psychiatric treatment commonly affects prolactin levels and thereby influences graft fate

Delirium, depression and other psychiatric difficulties are commonly encountered by posttransplantation patients, and antipsychotic medicines are frequently used to treat these difficulties. This article reviews previous research data concerning the immunological effects of these medicines, with particular focus on the consequences of prolactin elevation. Unproven but of concern is that these effects may influence graft fate. Older antipsychotic medicines such as haloperidol and chlorpromazine have a high likelihood of elevating prolactin. Prolactin is an immunologically active molecule generally promoting bone marrow function. This may be of benefit post-stem-cell transplant, helping engraftment, but could further rejection of solid-organ transplants. Elevated prolactin is implicated in the facilitation of graft-versus-host disease. Aripiprazole is the antipsychotic medicine least likely to increase prolactin (and may actually decrease prolactin); risperidone, the most likely to increase prolactin. Olanzapine, quetiapine and ziprazadone are antipsychotic medicines with a lower likelihood of elevating prolactin. Older ("neuroleptic") antipsychotics, such as chlorpromazine, droperidol and haloperidol, perphenazine and many others, are likely to elevate serum prolactin. Among antidepressants, most serotonin reuptake inhibitors, with the exception of sertraline, can slightly elevate prolactin. The atypical (i.e., alone in their class) antidepressants bupropion and mirtazapine are prolactin neutral. The immunological consequences of psychiatric medicines should be considered when treating transplant patients for delirium, depression and thought disorders; in addition, if elevation of prolactin is thought to be of immunological importance during psychiatric treatment, then it should be monitored and treated. The dopamine agonists used to treat Parkinson's disease--bromocriptine, pergolide, pramipexole, ropinerole--usually reverse antipsychotic-induced prolactin increases without compromising psychiatric effectiveness.

Proinflammatory cytokines inhibit human placental 11beta-hydroxysteroid dehydrogenase type 2 activity through Ca2+ and cAMP pathways

Excessive fetal exposure to glucocorticoids has been implicated in the etiology of adult metabolic and cardiovascular disease. Placental 11beta-hydroxysteroid dehydrogenase type 2 (11beta-HSD2) may protect the fetus from excessive glucocorticoid exposure. Maternal stress may be accompanied by elevated levels of cortisol and increased proinflammatory cytokines [interleukin (IL)-1beta, IL-6, and tumor necrosis factor-alpha (TNF-alpha)]. We hypothesize that proinflammatory cytokines inhibit human placental 11beta-HSD activity. We incubated explant cultures of term human placental villi in the presence or absence of 10 ng/ml IL-1beta, IL-6, or TNF-alpha, with or without agonists or antagonists of intracellular Ca2+ and adenylyl cyclase. Activity for 11beta-HSD2 was estimated using a radioisotope assay, and mRNA was measured using quantitative RT-PCR. All cytokines significantly (P < or = 0.05) reduced 11beta-HSD2 activity (>75% suppression); maximal inhibition occurred within 2 h and was maintained for at least 24 h. The IL-1beta-induced inhibitory activity was attenuated using a Ca2+ channel blocker (nifedipine), an intracellular Ca2+ antagonist [8-(N,N-diethylamino)octyl-3,4,5-trimethoxybenzoate], or the adenylyl cyclase stimulant forskolin. Conversely, 11beta-HSD2 activity was diminished in the presence of the Ca2+ ionophore A-23187 or the adenylyl cyclase inhibitor SQ-22536. mRNA levels for 11beta-HSD2 were not changed by any of the treatments. Proinflammatory cytokines inhibit human placental 11beta-HSD2 activity through a mechanism that involves increased intracellular Ca2+ and inhibition of adenylyl cyclase. This could result in excessive fetal exposure to maternal cortisol. This mechanism might mediate part of the increased risk of metabolic and cardiovascular disease in adult offspring.

A new chapter opens in anti-inflammatory treatments: the antidepressant bupropion lowers production of tumor necrosis factor-alpha and interferon-gamma in mice

In a wide range of human diseases of inflammatory nature like Crohn's disease, pathology is mediated in part by pro-inflammatory cytokines like tumor necrosis factor-alpha (TNF) or interferon-gamma. We show here that a commonly used generic antidepressant bupropion, in wide use worldwide to treat depression in humans for a decade now, profoundly lowers levels of TNF, interferon-gamma, and interleukin-1 beta in vivo, in a mouse lipopolysaccharide (LPS) induced inflammation model. Mice challenged with an otherwise lethal dose of LPS were protected by bupropion and levels of the anti-inflammatory cytokine interleukin-10 were increased. Previous data in rodents and humans indicate antidepressant effects of bupropion are mediated by its weak reuptake inhibition of norepinephrine and dopamine. Concordant with this, TNF suppression by bupropion in our mouse LPS model was largely abrogated by beta-adrenergic or dopamine D1 receptor antagonists but not by a D2 antagonist. TNF synthesis is controlled by an inverse relationship with intracellular cyclic adenosine monophosphate (cAMP) and stimulation of either beta-adrenoreceptors or D1 dopaminergic receptors result in increased cAMP but stimulation of D2 receptors lowers cAMP. We conclude that bupropion may suppress TNF synthesis by mediating increased signaling at beta-adrenoreceptors and D1 receptors, resulting in increased cAMP that inhibits TNF synthesis. Bupropion is well tolerated also in non-psychiatric populations and has less risk with long term use than current anti-inflammatory, immunosuppressive or TNF suppressive treatments such as prednisone, azathioprine, infliximab, or methotrexate. New anti-inflammatory treatments are needed. We believe a new chapter in antiinflammatory, TNF lowering treatment of disease has been opened. Bupropion's use for this in humans should be explored.

Inhibitory effects of the beta-adrenergic receptor agonist zilpaterol on the LPS-induced production of TNF-alpha in vitro and in vivo

In this study the anti-inflammatory properties of zilpaterol, a beta2-adrenergic receptor (AR) agonist specifically developed as a growth promoter in cattle were investigated. Although zilpaterol has a different structure compared with the beta2-AR agonists known to date, it was noted that it was able to bind to both the beta2-AR (Ki = 1.1 x 10(-6)) and the beta1-AR (Ki = 1.0 x 10(-5)). Using lipopolysaccharide (LPS)-exposed U937 macrophages, the production of cyclic adenosine-3',5'-cyclic monophosphate (cAMP) and tumor necrosis factor alpha (TNF-alpha) were investigated. Zilpaterol inhibited TNF-alpha release and induced intracellular cAMP levels in a dose-dependent manner. The inhibition of TNF-alpha release and induction of cAMP production was mainly mediated via the beta2-AR, as indicated by addition of beta1- and beta2-specific antagonists. The effects of zilpaterol were investigated in LPS-treated male Wistar rats after pretreatment with zilpaterol. Zilpaterol dosed at 500 microg/kg body weight reduced the TNF-alpha plasma levels. In conclusion, zilpaterol is a beta2-adrenergic agonist and an inhibitor of TNF-alpha production induced by LPS both in vivo and in vitro.

Unheated Cannabis sativa extracts and its major compound THC-acid have potential immuno-modulating properties not mediated by CB1 and CB2 receptor coupled pathways

There is a great interest in the pharmacological properties of cannabinoid like compounds that are not linked to the adverse effects of Delta(9)-tetrahydrocannabinol (THC), e.g. psychoactive properties. The present paper describes the potential immuno-modulating activity of unheated Cannabis sativa extracts and its main non-psychoactive constituent Delta(9)-tetrahydrocanabinoid acid (THCa). By heating Cannabis extracts, THCa was shown to be converted into THC. Unheated Cannabis extract and THCa were able to inhibit the tumor necrosis factor alpha (TNF-alpha) levels in culture supernatants from U937 macrophages and peripheral blood macrophages after stimulation with LPS in a dose-dependent manner. This inhibition persisted over a longer period of time, whereas after prolonged exposure time THC and heated Cannabis extract tend to induce the TNF-alpha level. Furthermore we demonstrated that THCa and THC show distinct effects on phosphatidylcholine specific phospholipase C (PC-PLC) activity. Unheated Cannabis extract and THCa inhibit the PC-PLC activity in a dose-dependent manner, while THC induced PC-PLC activity at high concentrations. These results suggest that THCa and THC exert their immuno-modulating effects via different metabolic pathways.

Autocrine activation of microglia by tumor necrosis factor-alpha

In the central nervous system (CNS), tumor necrosis factor-alpha (TNF-alpha) derived from activated microglia plays a critical role as an inflammatory mediator. In this study, we examined the function of TNF-alpha as an autocrine mediator in microglial activation. TNF-alpha induced TNF-alpha production by microglia through ligation of TNF receptor 1 (TNFR1). TNF-alpha also increased the production of other inflammatory mediators. The activation of microglia by lipopolysaccharide is partially mediated by microglia-derived TNF-alpha. These findings suggest the existence of a positive feedback loop in the activation of microglia via TNF-alpha. This autocrine loop may be involved in the prolonged activation of microglia.

Evidence of a mechanism by which etanercept increased TNF-alpha in multiple myeloma: new insights into the biology of TNF-alpha giving new treatment opportunities--the role of bupropion

Etanercept is a commercially available pharmaceutical protein approved for treatment of rheumatoid arthritis, RA. Given subcutaneously, etanercept binds and inactivates soluble tumor necrosis factor-alpha, TNF. Etanercept has a good safety record and is of benefit in lowering pain, inflammation, and joint destruction in RA. RA is mediated by many factors, TNF among them. Malignant myeloma, MM, is a malignant clonal expansion of a post-germinal center B lymphocyte. Since TNF is a necessary growth factor for expansion and maintenance of MM cells, and etanercept binds soluble TNF and is of clinical benefit in RA, etanercept was tried experimentally in MM. Contrary to expectations, etanercept resulted in increased levels of TNF and possibly shortened survival. This paper presents an hypothesis of how this happened. There are two cognate receptors for TNF, termed R1 and R2 and two forms of TNF, soluble and transmembrane. Soluble TNF has greater affinity for TNF-R1 than for TNF-R2. Transmembrane TNF has equal affinity for the two receptors. Since TNF-R2 signaling tends to be more anti-apoptotic and activating of nuclear factor kappa B, NFkB, than is TNF-R1, and TNF-R1 tends to be more pro-apoptotic than is TNF-R2, by inactivating soluble TNF while leaving transmembrane TNF signaling relatively unchanged, etanercept changed the balance in TNF signaling from TNF-R1 towards TNF-R2 weighting. Anti-apoptosis and TNF synthesis would have been up-regulated by that shift. Early data indicates that the common generic antidepressant bupropion may ameliorate Crohn's disease course by down regulating TNF synthesis, maybe it will slow the course of MM as well.

Effect of therapeutic plasma concentrations of non-steroidal anti-inflammatory drugs on the production of reactive oxygen species by activated rat neutrophils

The release of reactive oxygen specie (ROS) by activated neutrophil is involved in both the antimicrobial and deleterious effects in chronic inflammation. The objective of the present investigation was to determine the effect of therapeutic plasma concentrations of non-steroidal anti-inflammatory drugs (NSAIDs) on the production of ROS by stimulated rat neutrophils. Diclofenac (3.6 microM), indomethacin (12 microM), naproxen (160 microM), piroxicam (13 microM), and tenoxicam (30 microM) were incubated at 37 masculineC in PBS (10 mM), pH 7.4, for 30 min with rat neutrophils (1 x 10(6) cells/ml) stimulated by phorbol-12-myristate-13-acetate (100 nM). The ROS production was measured by luminol and lucigenin-dependent chemiluminescence. Except for naproxen, NSAIDs reduced ROS production: 58 +/- 2% diclofenac, 90 +/- 2% indomethacin, 33 +/- 3% piroxicam, and 45 +/- 6% tenoxicam (N = 6). For the lucigenin assay, naproxen, piroxicam and tenoxicam were ineffective. For indomethacin the inhibition was 52 +/- 5% and diclofenac showed amplification in the light emission of 181 +/- 60% (N = 6). Using the myeloperoxidase (MPO)/H2O2/luminol system, the effects of NSAIDs on MPO activity were also screened. We found that NSAIDs inhibited both the peroxidation and chlorinating activity of MPO as follows: diclofenac (36 +/- 10, 45 +/- 3%), indomethacin (97 +/- 2, 100 +/- 1%), naproxen (56 +/- 8, 76 +/- 3%), piroxicam (77 +/- 5, 99 +/- 1%), and tenoxicam (90 +/- 2, 100 +/- 1%), respectively (N = 3). These results show that therapeutic levels of NSAIDs are able to suppress the oxygen-dependent antimicrobial or oxidative functions of neutrophils by inhibiting the generation of hypochlorous acid.

Effects of culture with TNF-alpha, TGF-beta and insulin on sulphotransferase (SULT 1A1 and 1A3) activity in human colon and neuronal cell lines

The aim of the study was to determine whether the expression of sulphotransferase enzymes could be affected by the presence of cytokines or peptide hormones. The effects of cytokines (TNF-alpha and TGF-beta) and insulin on sulphotransferase (SULT 1A1 and 1A3) activity were studied in a human neuronal cell line (SK-N-SH) and a human gastrointestinal tract cell line (HT-29). Cells were cultured with varying concentrations of TNF-alpha, TGF-beta or insulin for 24 h; the SULT 1A1 isoform in the 2 cell lines showed different optimal substrate concentrations. There were no direct effects of cytokines on enzyme activity. Culture with TNF-alpha increased activity of both SULT 1A1 and 1A3 in the HT-29 cells; TGF-beta also increased activities of both isoforms but to a lesser extent; insulin increased activity of SULT 1A1 only. The cytokines and insulin had relatively little effect on sulphotransferase activity in the neuronal cell line. These results suggest that, unlike neuronal cells, gastrointestinal cells may respond to physiological states by altering sulphotransferase activity. As certain substrates such as diet-derived heterocyclic amines are bioactivated by sulphation to produce carcinogenic metabolites this may be a factor in the increased incidence of colorectal cancer in patients with inflammatory bowel disease or diabetes.

Identification of Necrosis-Associated Genes in Glioblastoma by cDNA Microarray Analysis

PURPOSE

In the field of cancer research, there has been a paucity of interest in necrosis, whereas studies focusing on apoptosis abound. In neuro-oncology, this is particularly surprising because of the importance of necrosis as a hallmark of glioblastoma (GBM), the most malignant and most common primary brain tumor, and the fact that the degree of necrosis has been shown to be inversely related to patient survival. It is therefore of considerable interest and importance to identify genes and gene products related to necrosis formation.

EXPERIMENTAL DESIGN

We used a nylon cDNA microarray to analyze mRNA expression of 588 universal cellular genes in 15 surgically resected human GBM samples with varying degrees of necrosis. Gene expression was correlated with the degree of necrosis using rank correlation coefficients. The expression of identified genes was compared with their expression in tissue samples from 5 anaplastic astrocytomas (AAs). Immunostaining was used to determine whether genes showing the most positive correlation with necrosis were increasingly expressed in tumor tissues, as grade of necrosis increased.

RESULTS

The hybridization results indicated that 26 genes showed significant correlation with the amount of necrosis. All 26 genes had functions associated with either Ras, Akt, tumor necrosis factor alpha, nuclear factor kappaB, apoptosis, procoagulation, or hypoxia. Nine genes were positively correlated with necrosis grade, and 17 genes were negatively correlated with necrosis grade. There were significant differences in the median expression levels of 3 of the 26 genes between grade III necrosis GBM and anaplastic astrocytoma (AA) samples; all but 1 of the genes had elevated expression when comparing necrosis grade III with AA samples. Two factors, the ephrin type A receptor 1 and the prostaglandin E(2) receptor EP4 subtype, not previously considered in this context, were highlighted because of their particularly high (positive) correlation coefficients; immunostaining showed the products of these two genes to be localized in perinecrotic and necrotic regions and to be overexpressed in grade III GBMs, but not AAs. These two molecules also showed significant correlation with survival of GBM patients (P = 0.0034) in a combined model.

CONCLUSIONS

The application of cDNA expression microarray analysis has identified specific genes and patterns of gene expression that may help elucidate the molecular basis of necrogenesis in GBM. Additional studies will be required to further investigate and confirm these findings.

Anti-inflammatory and utero-relaxant effects in human myometrium of new generation phosphodiesterase 4 inhibitors

The anti-inflammatory and utero-relaxant effects of two potent phosphodiesterase 4 (PDE4) inhibitors of the latest generation: cilomilast (one of the most advanced PDE4 inhibitors in clinical development, reportedly more selective for PDE4D) and compound A (which displays 12-fold greater selectivity toward PDE4B and/or PDE4A than toward PDE4D) were evaluated in human uterine smooth muscle. We first established that these compounds exhibit greater efficacy in inhibiting total cAMP-PDE activity in pregnant versus nonpregnant myometrium (E(max) = 78.0% +/- 3.6% and 80.3% +/- 2.2% in pregnant versus 57% +/- 4.7% and 70.5% +/- 5.9% in nonpregnant women for compound A and cilomilast, respectively; P < 0.05 for both compounds), confirming the prominent participation of PDE4 isoforms in cAMP hydrolysis in the near-term pregnant myometrium. Using pregnant myometrial explants, we have shown that both these drugs and also rolipram, the prototype PDE4 inhibitor, produce concentration-dependent inhibition of lipopolysaccharide (LPS) induced tumor necrosis factor alpha (TNFalpha) release with similar potency in each case (pD2 = 8.0 +/- 0.5, 7.9 +/- 0.2, and 7.6 +/- 0.2 for compound A, cilomilast, and rolipram, respectively). The maximum inhibition produced is 65%. Pretreatment with forskolin or 8-bromo-cAMP mimics the PDE4 inhibitor effect. Furthermore, compound A and cilomilast both produce concentration-dependent inhibition of the spontaneous contractions of myometrial strips and are more potent in pregnant than in nonpregnant myometrium (pD2 = 7.3 +/- 0.7 and 8.1 +/- 0.3 in pregnant versus 6.2 +/- 0.9 and 6.6 +/- 0.1 in nonpregnant myometrium for compound A and cilomilast, respectively; P < 0.05 for both compounds). This demonstrates that the PDE4 isoforms involved in the mechanism of contraction are different in the pregnant and nonpregnant myometrium. Our study highlights the importance of developing PDE4 inhibitors for the pharmacological management of infection-induced preterm labor.

Mechanisms of NSAID-induced hepatotoxicity: focus on nimesulide

Nonsteroidal anti-inflammatory drugs (NSAIDs) have been associated with idiosyncratic hepatotoxicity in susceptible patients. The molecular mechanisms underlying this toxicity have not yet been fully elucidated. However, experimental evidence suggests that they include increased concentration of the drugs in the hepatobiliary compartment, formation of reactive metabolites that covalently modify proteins and produce oxidative stress, and mitochondrial injury. Genetic and/or acquired patient factors can either augment the pathways leading to hepatic toxicity or impede the protective and detoxifying pathways. An example is nimesulide, a selective cyclo-oxygenase-2 inhibitor widely used for the treatment of inflammatory and pain conditions, which has been recently associated with rare but serious and unpredictable adverse reactions in the liver (increases in serum aminotransferase activities, hepatocellular necrosis, and/or intrahepatic cholestasis). Similar to other drugs causing idiosyncratic hepatotoxicity, both the molecule and the patient contribute to the hazard. Here, the weakly acidic sulfonanilide drug undergoes bioreductive metabolism of the nitroarene group to reactive intermediates that have been implicated in oxidative stress, covalent binding, and mitochondrial injury. It is only in a small number of susceptible patients, however, that genetic or nongenetic factors will cause this potential toxicity to become clinically manifest. In view of the very large recipient population, the incidence of nimesulide-induced liver injury has been low (approximately 0.1 per 100,000 patients treated). Although this estimation is based on spontaneous reporting data versus sales units and needs correction due to the classical bias of this system, the type and incidence of these rare but severe hepatic adverse reactions are comparable to that of other NSAIDs.

Regulation of proteinase-activated receptor 1 by inflammatory mediators in human vascular endothelial cells

Thrombin plays a critical role in haemostasis, inflammation, and cell proliferation, mediated by proteinase-activated receptor 1 (PAR-1; thrombin receptor). The physiological and pathological regulation of PAR-1 by inflammatory mediators has not yet been fully elucidated. The aim of this study is to investigate the effects of inflammatory mediators on mRNA and protein expression of PAR-1 in early passage human vascular endothelial cells. Endothelial cells were activated by inflammatory mediators, such as tumour necrosis factor alpha (TNFalpha), interferon gamma (IFN gamma), and bacterial substance lipopolysaccharide (LPS), and the PAR-1 expression was verified by flow cytometry or RT-PCR. By stimulating endothelial cells with TNFalpha, IFN gamma, and LPS, the PAR-1 expression on the cell surface remained almost unchanged for 48 h. After stimulation with 20-300 U/ml TNFalpha, the total cellular PAR-1 expression (both on cell surface and in the cytoplasm) significantly decreased at 24h and thereafter recovered to the basal level at 48 h. The stimulation with 100 U/ml TNFalpha transiently down-regulated the PAR-1 mRNA expression to approximately 0.3-fold of the basal level at 30 min, but it rebounded 3-fold above the basal level at 6h, and again decreased to 0.5-fold of the basal level at 12h, and finally returned to the basal level at 24h. In contrast, IFN gamma or LPS did not affect the PAR-1 mRNA expression.

Borage oil reduction of rheumatoid arthritis activity may be mediated by increased cAMP that suppresses tumor necrosis factor-alpha

Recent double blind studies have shown some benefit of borage oil in treatment of rheumatoid arthritis. Tumor necrosis factor-alpha has been shown to be a central mediator of inflammatory and joint destructive processes in rheumatoid arthritis. In this paper, evidence from published research is reviewed that indicates gamma linolenic acid component of borage oil increases prostaglandin E levels that increase cAMP levels that in turn suppress tumor necrosis factor-alpha synthesis. If this biochemical path of borage oil is correct then (1) concomitant non-steroidal anti-inflammatory drug use would tend to undermine borage oil effects, and (2) borage oil would be contraindicated in pregnancy given the teratogenic and labor inducing effects of prostaglandin E agonists.