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Objectives Microsomal prostaglandin E synthase-1 (mPGES-1) catalyses the formation of PGE2 in inflammatory tissues. It is considered a potential drug target in inflammatory conditions to achieve clinical benefits comparable to NSAIDs with a better tolerability. Inhibitors of mPGES-1 are under development but the pharmacological regulation of mPGES-1 expression remains poorly known. MAP kinase phosphatase-1 (MKP-1) is an enzyme that limits the activity of pro-inflammatory MAP kinases p38 and JNK. In the present study, we discovered that dexamethasone down-regulates mPGES-1 expression in articular chondrocytes in an MKP-1 and p38 kinase dependent manner. Methods Primary human chondrocytes were isolated from cartilage samples obtained from osteoarthritis (OA) patients undergoing knee replacement surgery. Primary mouse chondrocytes were isolated from cartilage samples of MKP-1 deficient (knock-out, KO) and corresponding wild type (WT) mice. Expression of mPGES-1 and MKP-1 were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR) and Western blot, and MAP kinase phosphorylation by Western blot. Results Dexamethasone inhibited the expression of mPGES-1 in primary human chondrocytes and in chondrocytes from wild type but not from MKP-1 deficient mice. Dexamethasone enhanced MKP-1 expression in chondrocytes from wild type mice as well as in primary human OA chondrocytes. Dexamethasone induced the dephosphorylation of both p38 and JNK, whereas mPGES-1 expression was downregulated by selective inhibitors of p38 only. Conclusions The results show that MKP-1 is a crucial mediator of pharmacological control of inflammatory mPGES-1 expression by glucocorticoids, and underline MKP-1 as a potential anti-inflammatory drug target.

Patients with depression and alcohol use disorder frequently present with elevated markers of inflammation. Adipose tissue may function as a source for inflammation, yet the interplay between adiposity, alcohol use and depression has remained unknown. We examined 242 patients, referred to treatment for depressive symptoms, and followed for a period of 6 months. The assessments included screening for alcohol use and measurements of body mass index, serum adiponectin, leptin, resistin, progranulin, hs-CRP, IL-6 and MCP-1 at baseline and after 6 months of treatment. During follow-up, mean MADRS and AUDIT scores decreased significantly, whereas BMI increased. The changes in the levels of cytokines and adipokines were influenced by alcohol consumption and adiposity in a gender-dependent manner. The presence of AUD seemed to particularly influence the levels of cytokines. The levels of IL-6, hs-CRP, progranulin, and leptin differed between AUD and non-AUD groups at baseline, but no longer at 6 months. Baseline levels of leptin and resistin were higher in women and changes occurring in leptin, progranulin, and adiponectin were more notable in women. The data indicates significant gender-dependent interactions between depression, alcohol and mediators of inflammation, which should be considered in studies on the pathogenesis of depression and its comorbidities.

Experimental and clinical reports highlight the role of cytokines in pathophysiological processes in underpinning epilepsy, but the clinical data remains somewhat limited. The levels of Interleukin (IL)-6 were measured in serum from 49 patients with refractory epilepsy [temporal lobe epilepsy (TLE, n=23), extratemporal lobe epilepsy (XLE, n=22), and idiopathic generalized epilepsy (IGE, n=4)] before and after the first verified seizure (IS; index seizure) during inpatient video-electroencephalographic (VEEG) monitoring. The levels of IL-6 increased significantly at all time points between 3h and 24h after the IS compared to the baseline. IL-6 concentrations were significantly higher at the 3h and 6h time point after tonic-clonic seizures (TCS) compared to the situation with simple partial and complex partial seizures. An IS duration longer than 100s, low baseline IL-6 level and10 seizures/month in patients with TLE were associated with an increase in IL-6 concentrations during the 24h after the IS. In patients with TLE, the maximum change in IL-6 levels after IS was significantly higher than in XLE. If the baseline level of IL-6 was low (under 5pg/ml), seizures induced a significant elevation in both absolute and relative values in TLE patients but not in XLE. In patients with ≤10 seizures per month during the last year, the maximum change was higher than in patients with10 seizures. If the total seizure burden during registration was ≥100s, the IL-6 increase was significantly higher than if it were under 100s. The results of this study highlight the complexity of factors involved in the seizure induced production of the inflammatory cytokine, IL-6. The major factor is the epilepsy type i.e. increased production of IL-6 in TLE compared to XLE. The response to a single seizure in TLE is dependent on the previous seizure frequency and the baseline IL-6 concentration.

Metabolic syndrome and related cardiovascular risk factors are well-known comorbidities among patients with schizophrenia. Biomarkers of these antipsychotic-associated metabolic adverse effects and antipsychotic-induced weight gain are needed. Glucagon-like peptide-1 (GLP-1) is involved in insulin secretion, regulation of satiety, inhibition of food intake, and inhibition of gastric emptying. GLP-1 also induces reduction in body weight. Visfatin/ NAMPT/ PBEF is an adipocytokine secreted by several cells and tissues. Increased plasma visfatin levels have been associated with overweight/obesity, type 2 diabetes mellitus, insulin resistance, metabolic syndrome and cardiovascular diseases, low grade inflammation, and proinflammatory markers. Associations between antipsychotic-induced weight gain and serum visfatin and GLP-1 levels have been little studied in patients with schizophrenia. The aim of the present study was to test the possible role of serum GLP-1 and visfatin level alterations as markers of weight gain in association with metabolic and inflammatory markers in 190 patients (109 male, 81 female) with schizophrenia on clozapine treatment. High serum levels of GLP-1 correlated significantly with higher levels of visfatin, leptin, insulin, HOMA-IR, higher BMI, and weight change among men. Associations between serum visfatin levels and BMI or weight change were not found in the present patients. Serum GLP-1 level seems to be a marker of metabolic risk factors among men with schizophrenia on clozapine treatment. Female patients may be more sensitive to suppressive effects of clozapine on GLP-1 secretion. Patients on clozapine would benefit from GLP-1 agonists as preventive treatment. publishedVersion

β2-receptor agonists are used in the treatment of inflammatory obstructive lung diseases asthma and COPD as a symptomatic remedy, but they have been suggested to possess anti-inflammatory properties, also. β2-receptor activation is considered to lead to the activation of ERK pathway through G-protein- and cAMP-independent mechanisms. In this study, we investigated the effects of β2-receptor agonists salbutamol and terbutaline on the production of inflammatory factors in macrophages. We found that β2-receptor agonists inhibited LPS-induced ERK phosphorylation and the production of MCP-1. A chemical cAMP analog 8-Br-cAMP also inhibited ERK phosphorylation and TNF and MCP-1 release. As expected, MAPK/ERK kinase (MEK)1/2 inhibitor PD0325901 inhibited ERK phosphorylation and suppressed both TNF and MCP-1 production. In conclusion, we suggest that β2-receptor agonists salbutamol and terbutaline inhibit inflammatory gene expression partly by a mechanism dependent on cAMP leading to the inhibition of ERK signaling in macrophages. Observed anti-inflammatory effects of β2-receptor agonists may contribute to the clinical effects of these drugs.

Objective Patients with aneurysmal subarachnoid hemorrhage (aSAH) experience high mortality and morbidity. Neuroinflammation causes brain damage expansion after aSAH. Due to the complexity of the inflammatory response multiple biomarkers are needed to evaluate its' progression. We studied inflammatory process after aSAH by measuring two inflammatory biomarkers, interleukin-6 (IL-6) and high-mobility group box 1 (HMGB1) at simultaneous time-points after aSAH. Methods In this prospective population-based study, IL-6 and HMGB1 were measured in aSAH patients (n = 47) for up to five days. Plasma concentrations of IL-6 and HMGB1 were measured at 0, 12 and 24 h after hospital admission, and thereafter daily for up to five days or until the patient was transferred from the intensive care unit (ICU). The patients' neurological outcomes were evaluated with the modified Rankin Scale at six months after aSAH. Results A high IL-6 level during the first day after aSAH was associated with a severe initial clinical presentation (p = 0.002) and infection during follow-up (p = 0.031). The HMGB1 level did not associate with these parameters. There was no correlation between IL-6 and HMGB1 levels at any time point during the follow-up. The concentrations of IL-6 and HMGB1 were not associated with neurological outcome. Conclusions High initial IL-6 values seem to reflect the intensity of the inflammatory response but not the brain damage per se. An early inflammatory response might even be beneficial since although elevated IL-6 levels were observed in patients with a more severe initial clinical presentation, they were not associated with neurological outcome. The lack of correlation between IL-6 and HMGB1 questions the role of macrophages in the process of the secretion of these inflammatory markers after aSAH, instead pointing to the activation of alternative pro-inflammatory pathways., Highlights • IL-6 reflects the intensity of inflammation after aSAH without association to neurological outcome. • Early inflammatory response might even be beneficial after aSAH. • Lack of correlation between IL-6 and HMGB1 questions the role of macrophages in inflammatory response after aSAH.

Purpose Adipokines, especially leptin and adiponectin, have gained increasing importance in pathophysiology of various neurological diseases including epilepsy. There are experimental data suggesting a role for leptin in the genesis of seizures and neuroprotection related to seizures. However there are no clinical studies on the effects of epileptic seizures on adipokines. Methods We measured cerebrospinal fluid (CSF) and plasma levels of leptin, adiponectin and adipsin after provoked or unprovoked primary or secondarily generalized tonic–clonic seizures in 13 female patients and seven controls. The samples were taken within 24h after the seizure onset. Results Leptin plasma levels correlated negatively with the time to sample withdrawal, i.e. the longer the time interval between the seizure and the sample the lower the leptin levels in the patients. Interestingly, plasma adiponectin levels were significantly increased after the seizure episode. Conclusion This study provides further evidence that there are seizure-induced acute changes in adipokine metabolism. Leptin concentrations seem to decrease during the first 24h after the seizure whereas adiponectin levels increase. The meaning of this response is far from clear, but it might be an endogenous attempt to prevent harmful effects of epileptic seizures in the central nervous system.

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s / Osteoarthritis and Cartilage 24 (2016) S63eS534 S78 118 ADIPOKINES LEPTIN, ADIPONECTIN AND RESISTIN AND THEIR ASSOCIATIONS TO MMPS, IL-6, COMP AND RADIOGRAPHIC SEVERITY OF OA A. Koskinen-Kolasa y, K. Vuolteenaho y, T. Moilanen z, E. Moilanen y. y The Immunopharmacology Res. Group, Univ. of Tampere Sch. of Med. and Tampere Univ. Hosp., Tampere, Finland; zCoxa Hosp. for Joint Replacement, Tampere, Finland Purpose: Obesity and metabolic syndrome (MetS) are associated with an increased risk of osteoarthritis (OA). Obesity has been claimed to contribute to the development of OA by increasing the load on weightbearing joints. However, this appears to be an over-simplification, since obesity is also linked to OA in the hand and finger joints. Adipocytes, the cells in the adipose tissue, secrete adipokines, which were first found to regulate energy metabolism and appetite. Today we know that adipokines are also produced by many other tissues and cells including joint tissues and that they are involved in the inflammatory responses. We report here the levels of leptin, adiponectin and resistin measured in plasma, synovial fluid and cartilage samples obtained from 100 OA patients as well as their associations to MMPs, IL-6, COMP and radiographic severity of OA. Methods: Cartilage samples, synovial fluid and blood samples, as well as clinical data, were collected from 100 OA patients [BMI 29.7 (8.3) kg/m2, Adipokine levels in plasma, synovial fluid and cartilage culture supernatant and correlations to BMI All (n1⁄4 100) Females (n1⁄4 62) Males (n1⁄4 38) p (F vs M) Median IQR Median IQR Median IQR P-leptin (ng/ml) Correlation to BMI 19.8 r1⁄4 0.67 22.4 p 30 kg/m2; non-obese, BMI < 30 kg/m2), and it was found to correlate with the MMPs only in obese patients (MMP-1: r1⁄4 0.49, p1⁄4 0.001, MMP-3: r1⁄4 0.48, p1⁄4 0.001). Of note, no correlation between BMI and MMPs was found. In cartilage culture media adiponectin correlated positively with the levels of MMP-1, MMP-3, MMP-13 and IL-6 (Table 2). Resistin levels in cartilage culture media correlated with MMP-1 and MMP-13 (Table 2). Associations with radiographic findings and biomarkers of OA In males plasma and cartilage culture media adiponectin was found to be the highest in the patients with the most severe radiographic findings. Plasma adiponectin correlated positively also with circulating biomarkers COMP (r1⁄4 0.55, p1⁄4 0.001) and MMP-3 (r1⁄4 0.34, p1⁄4 0.046) in males. There were no significant differences in leptin levels between radiographic subgroups whereas SF-resistin in females was higher in the group of radiographically most severe OA. Conclusions: These results support the idea that adipokines link obesity to OA, and hold promise as biomarkers and targets for diseasemodifying drugs in OA. 119 YKL-40 IS ASSOCIATED WITH INFLAMMATION AND MMPS IN OSTEOARTHRITIS T. V€ a€ an€ anen y, M. H€ am€al€ainen y, A. Koskinen y, E.-L. Paukkeri y, T. Moilanen yz, E. Moilanen y, K. Vuolteenaho y. y The Immunopharmacology Res. Group, Univ. of Tampere Sch. of Med. and Tampere Univ. Hosp., Tampere, Finland; zCoxa Hosp. for Joint Replacement, Tampere, Finland Purpose: YKL-40 is associated with inflammation and tissue injury in diseases such as asthma and rheumatoid arthritis. It has been shown to be produced by macrophages and some tissue cells as well as by cancer cells. Increased circulating YKL-40 levels have been reported in patients with osteoarthritis (OA). However, the role of YKL-40 in OA joints remains largely unknown. In the present study, we investigated the levels of YKL-40 in simultaneously collected plasma, synovial fluid (SF) and cartilage samples from OA patients undergoing knee replacement

SummaryObjectivesAsbestos-exposure causes an inflammatory response driven by alveolar macrophages that can lead to pulmonary fibrosis. In addition to classical inflammatory cytokines, macrophages produce adipokines which regulate the inflammatory response. We studied if adipokines are related to the degree of parenchymal fibrosis, impaired lung function and inflammation in asbestos-exposed subjects.MethodsEighty-five males with moderate to heavy occupational exposure to asbestos and unexposed controls were studied. We measured plasma levels of adipokines adiponectin, adipsin, leptin and resistin, IL-6, IL-8, erythrocyte sedimentation rate (ERS), spirometry and DL,CO. Degree of interstitial lung fibrosis (septal thickening, subpleural lines, parenchymal bands or honeycombing) was scored in classes 0–5 according to a validated scoring system. The subjects were divided into three groups: normal parenchymal finding (fibrosis class 0), borderline changes (classes 0.5–1.5) and fibrosis (i.e. asbestosis; classes 2–5).ResultsAdipsin correlated positively with parenchymal fibrosis (rho=0.412, p

The mechanisms of cough in asthma are unclear. Asthma is associated with an oxidative stress. Many reactive oxygen species sensitize or activate sensory C-fibers which are capable to induce cough. It was hypothesized that oxidative stress in the airways might contribute to the cough severity in asthma. Exhaled breath condensate samples were collected in ten healthy and 26 asthmatic subjects. The concentration of 8-isoprostane was measured. In addition, the subjects filled in Leicester Cough Questionnaire and underwent cough provocation tests with dry air hyperpnoea and hypertonic saline, among other measurements. Among the asthmatic subjects, high 8-isoprostane was associated with severe cough response to hyperpnoea (p=0.001), low Leicester Cough Questionnaire values (indicating severe subjective cough, p=0.02), and usage of combination asthma drugs (p=0.03-0.04). However, the 8-isoprostane concentrations did not differ significantly between the healthy and the asthmatic subjects. Airway oxidative stress may be associated with experienced cough severity and measured cough sensitivity in asthma.

Eosinophils play a major role in asthma. One described mechanism leading to the impaired clearance of these cells from the lung is the delay in their programmed cell death (apoptosis). β(2)-Adrenoceptor agonists have been shown to prolong survival and delay apoptosis of eosinophils. The aim of the present study was to evaluate the mechanisms, especially the role of cAMP pathway, in the prolongation of human eosinophil survival by a selective β(2)-agonist salbutamol. Isolated human peripheral blood eosinophils were cultured in the absence or presence of a β(2)-agonist salbutamol and the indicated antagonists/inhibitors under sterile conditions. Apoptosis was measured by using the relative DNA fragmentation assay and Annexin-V binding. Salbutamol prolonged survival of human eosinophils and it was inhibited by a β-receptor antagonist propranolol and mimicked by cell-permeant cAMP analogues dibutyryl- and 8-bromo-cAMP. Pharmacological inhibitors of adenylyl cyclase (SQ-22,536) and protein kinase A (Rp-8-CPT-cAMPS) antagonized the effects of salbutamol. The survival-prolonging action of salbutamol was potentiated by a phosphodiesterase inhibitor rolipram (EC(50) for the salbutamol effect was 13.6 ± 4.0 and 8.1 ± 3.1 nM in the absence and presence of rolipram, respectively; p=0.0142, n=10). In contrast, inhibition of Ca(2+)-activated K(+)-channels by apamin, charybdotoxin, iberiotoxin or paxilline did not affect the ability of salbutamol to prolong eosinophil survival. Taken together, the present results suggest that salbutamol at clinically relevant concentrations decreases apoptosis in human eosinophils by activating the cannonical β(2)-receptor-adenylyl cyclase-cAMP-protein kinase A pathway.

Asthma is characterized by accumulation of eosinophils in the lungs and delayed apoptosis may be one mechanism leading to eosinophilia. Nitric oxide (NO), present in inflamed lungs, has been shown to possess both anti- and proeosinophilic properties. We previously showed that NO induces apoptosis in the presence of survival prolonging cytokine IL-5 in human eosinophils. In the present study, we examined the intracellular mechanisms of NO-induced apoptosis in granulocyte macrophage-colony stimulating factor (GM-CSF)-treated eosinophils concentrating on the role of caspases and calpains. Eosinophils were isolated from human blood and apoptosis was determined by relative DNA fragmentation assay, morphological analysis and/or Annexin-V FITC assay. We showed that NO-donor S-nitroso-N-acetyl-d,l-penicillamine (SNAP) induced apoptosis in GM-CSF-treated eosinophils. SNAP-induced DNA fragmentation was totally prevented by an inhibitor of caspase-6 (Z-VEID-FMK). Decreased levels of caspase-6 proenzyme and increased amounts of cleaved lamin A/C in SNAP-treated cells indicated activation of caspase-6. Furthermore, SNAP-induced lamin A/C and B fragmentation was totally abolished by an inhibitor of caspase-6. According to our results, caspase-6 mediates lamin and DNA fragmentation also in spontaneously dying eosinophils. Inhibitor of calpains prevented most of DNA fragmentation related to spontaneous apoptosis but had no effect in eosinophils undergoing NO-induced apoptosis. In the present study we showed that caspase-6 is essential for the executive phase involving lamin and DNA fragmentation in both NO-induced and spontaneous eosinophil apoptosis. However, differences in the involvement of calpains suggest that the intracellular signalling in NO-induced apoptosis has specific features at the level of proteases. This study demonstrates new mechanisms for NO-induced and spontaneous apoptosis in human eosinophils.

Tristetraprolin (TTP) binds to AU-rich elements within the mRNAs of several inflammatory genes and causes destabilization of the target mRNAs. The protein kinase C (PKC) pathway represents a major signalling system in inflammation and PKCdelta is one of the key isoenzymes in the regulation of inflammatory processes. In the present study, we investigated the role of PKCdelta in the regulation of the expression of tristetraprolin in activated macrophages by using the PKCdelta inhibitor, rottlerin, and by downregulating PKCdelta expression by using PKCdelta siRNA. TTP protein and mRNA expression were measured by Western blotting and quantitative RT-PCR, respectively. TTP and TNFalpha mRNA decays were studied by the actinomycin D assay. In addition, we measured nuclear translocation of transcription factors believed to be important for TTP transcription, i.e. NF-kappaB, AP-2, SP1 and EGR1. Downregulation of PKCdelta by siRNA decreased significantly TTP expression in activated macrophages. Rottlerin also decreased TTP expression in wild type cells but not in cells in which PKCdelta had been downregulated by siRNA. Rottlerin decreased TTP mRNA half-life as measured by actinomycin D assay but it did not affect the nuclear translocation of transcription factors NF-kappaB, Sp1, AP-2 or EGR1 (which have been shown to be involved in TTP transcription). In addition, rottlerin reduced the decay of TNFalpha mRNA, which is an important target of TTP. The results suggest that PKCdelta up-regulates the expression of TTP by stabilizing its mRNA which may serve as a feed-back loop to regulate the inflammatory response.

Objectives To investigate the oxidant effects of adriamycin-containing chemotherapy (CT), we evaluated various antioxidants, total antioxidant capacity (TRAP) and different parameters of oxidative and nitrosative stress during combination CT. Design and methods Blood samples were obtained from 16 small cell lung cancer patients at baseline and several times during the first, second and sixth CT cycles. Results There were significant decreases in serum urate and serum proteins during all cycles, serum TRAP during the first two cycles, plasma ascorbic acid and serum TBARS during the first cycle, and serum conjugated dienes and plasma alphatocopherol during the last cycle. The baseline levels of tocopherols increased significantly between the first and sixth CT cycles. Higher levels of baseline plasma thiols were associated with better overall survival ( p = 0.008). Conclusions Adriamycin-containing CT causes significant oxidative stress as implied by reduced levels of protective antioxidants. Long-term CT treatment seems to enhance lipid peroxidation.

Oligodeoxynucleotide (ODN) sequences containing unmethylated cytidine phosphate guanosine (CpG) motifs prevalent in bacterial DNA attenuate allergic lung inflammation in experimental models of asthma but failed to inhibit eosinophilia and improve lung function in patients with asthma. Bacterial respiratory tract infections exacerbate asthma in humans. Increased eosinophil survival is a critical factor leading to persistent eosinophilic airway inflammation. Apoptosis is regarded as a key mechanism in the resolution of eosinophilic inflammation. The aim of this study was to investigate the effects of bacterial DNA and CpG ODNs on human eosinophil apoptosis in vitro and to elucidate the signalling pathway. Eosinophils were isolated from human peripheral blood by CD16- or CD16-, CD19- and CD304-negative selection. Apoptosis was determined by flow cytometric analysis of relative DNA content, Annexin-V staining and/or morphological analysis. Toll-like receptor 9 (TLR9) expression was studied by using western blotting and intracellular flow cytometry. Bacterial DNA and phosphorothioate-modified CpG ODNs, but not vertebrate DNA, were found to delay spontaneous eosinophil apoptosis. The effect of CpG ODNs was dependent on endosomal acidification and reversed by inhibitory ODN, which suggests involvement of TLR9 pathway. Furthermore, we demonstrated TLR9 expression in eosinophils derived from both atopic and healthy donors. Non-CpG ODNs had occasionally parallel but less profound effect on eosinophil apoptosis, which was not dependent on endosomal acidification. The anti-apoptotic effect of CpG ODNs was dependent on phosphatidylinositol 3-kinase (PI3K) and nuclear factor-kappaB (NF-kappaB) but not mitogen-activated protein kinases (MAPKs) as determined by inhibitor studies. Although our results suggest CpG-dependent involvement of TLR9 in the action of phosphorothioate-modified ODNs, we interestingly found that the anti-apoptotic action of native bacterial DNA in eosinophils is not dependent on unmethylated CpG motifs. This suggests that bacterial DNA contains a currently unknown recognition structure lacking from vertebrate DNA. Bacterial DNA-mediated suppression of eosinophil apoptosis is a novel mechanism for exacerbation of eosinophilic lung inflammation associated with bacterial respiratory tract infection.

In inflammation, bacterial products and pro-inflammatory cytokines induce the expression of inducible nitric oxide synthase (iNOS) and formation of high amounts of nitric oxide (NO). In a number of inflammatory diseases NO has pro-inflammatory and cytotoxic effects. The aim of the present study was to investigate the effects of immunosuppressive drugs cyclosporin A (CsA), tacrolimus (FK-506) and pimecrolimus on NO production through iNOS pathway in activated macrophages and fibroblasts. Calcineurin inhibitors (CsA, FK-506 and pimecrolimus) inhibited NO production and iNOS expression in a concentration-dependent manner, CsA being more potent than FK-506 and pimecrolimus. No effect on the activation or activity of the transcription factors nuclear factor-κB (NF-κB) and signal transducer and activator of transcription 1 (STAT-1) was found. CsA, FK-506 and pimecrolimus did not reduce iNOS mRNA levels when measured 6–8 h after the inflammatory stimulus, but significantly lower levels of iNOS mRNA were found after 24 h incubation. Also, in cells transfected with a luciferase gene under the control of 3′ untranslated region (3′UTR) of iNOS, CsA reduced luciferase activity. In conclusion, the results suggest that calcineurin inhibitors cyclosporin A, tacrolimus (FK-506) and pimecrolimus inhibit iNOS expression and NO production in response to inflammatory stimuli by enhancing the decay of iNOS mRNA by a 3′UTR-dependent manner. The findings add our knowledge on the anti-inflammatory effects of CsA, FK-506 and pimecrolimus, and suggest that calcineurin may have a role in the regulation of iNOS expression.

In asthma and chronic obstructive pulmonary disease (COPD), the number of eosinophils and neutrophils in the lung is increased. One described mechanism leading to the impaired clearance of these cells from the lung is the delay in their programmed cell death (apoptosis). Selective inhibitors of phosphodiesterases (PDEs) are under development for the treatment of lung diseases because of their anti-inflammatory and bronchodilator activity. The aim of the present study was to establish whether inhibitors of PDE3, PDE4 and PDE5 modulate human eosinophil or neutrophil apoptosis or beta 2-adrenoceptor agonist- or cytokine-afforded survival. We also evaluated whether a PDE4 inhibitor could modulate the effect of a corticosteroid on eosinophil and neutrophil apoptosis. Apoptosis was measured by using the relative DNA fragmentation assay and Annexin-V binding. Inhibitors of PDE4 (rolipram; 0.1-10 microM) and PDE3 (cilostazol; 0.1-10 microM) delayed spontaneous eosinophil apoptosis maximally by 25% and 15%, respectively. A combination of a PDE4 or PDE3 inhibitor (10 microM) with salbutamol (100 nM) further delayed eosinophil apoptosis maximally by 42-49%. In neutrophils, rolipram (10 microM) also decreased apoptosis with a maximal inhibition of 13%. The combination of rolipram (10 microM) and salbutamol (100 nM) produced a 27% inhibition of neutrophil apoptosis. Inhibitor of cGMP-specific PDE5 (zaprinast; 0.1-10 microM) did not affect eosinophil apoptosis and only slightly increased spontaneous neutrophil apoptosis. The effect of budesonide on apoptosis was not significantly modulated by a PDE4 inhibitor in eosinophils or neutrophils. The present results show that selective inhibitors of cAMP-hydrolyzing PDEs (PDE3 and PDE4) delay eosinophil apoptosis and, thus, increase their survival in vitro. Furthermore, beta 2-adrenoceptor agonists enhance the anti-apoptotic effects of PDE3 and PDE4 inhibitors, suggesting that such drug combinations may prolong eosinophil and neutrophil longevity in the lung.

In inflammation, nitric oxide (NO) is produced by inducible nitric oxide synthase (iNOS) induced by bacterial products and cytokines, and NO acts as a regulatory and pro-inflammatory mediator. Glucocorticoids are powerful anti-inflammatory agents that inhibit the expression of iNOS and various other inflammatory factors. Histone deacetylation has been recently described as a novel mechanism how glucocorticoids down-regulate transcriptional activation of some inflammatory genes. The aim of the present study was to investigate the effects of inhibitors of histone deacetylation on the suppressive effects of glucocorticoids on NO production and iNOS expression. Dexamethasone and a dissociated glucocorticoid RU24858 inhibited NO production, and iNOS protein and mRNA expression in macrophages exposed to bacterial lipopolysaccharide (LPS). In the presence of a glucocorticoid receptor (GR) antagonist mifepristone, dexamethasone and RU24858 had no effect on NO production. The role of histone deacetylation in the glucocorticoid effect was studied by using three structurally different inhibitors of histone deacetylases (HDACs): trichostatin A, apicidin and MC1293. HDAC inhibitors reversed the effects of dexamethasone and RU24858 on iNOS expression and NO production. Stably transfected A549/8 cells containing luciferase gene under the control of human iNOS promoter were used in promoter-activity studies. iNOS promoter activity induced by IL-1beta was inhibited by dexamethasone and the inhibitory effect was reversed by HDAC inhibitor trichostatin A. The results suggest that glucocorticoids inhibit iNOS expression and NO production by a GR-mediated and GRE-independent manner through histone deacetylation and transcriptional silencing.

Bacterial endotoxin is a potent inducer of inflammatory response, including the induction of inducible nitric oxide synthase (iNOS) expression and nitric oxide (NO) production, and the expression of cyclo-oxygenase (COX)-2 and tumor necrosis factor (TNF)-alpha in inflammatory cells. In the present study, we investigated the effects of pharmacological inhibition of Janus kinase (JAK) 3 on the production of these proinflammatory molecules in macrophages exposed to bacterial endotoxin (lipopolysaccharide; LPS). JAK3 inhibitors WHI-P154 (4-(3'-bromo-4'-hydroxylphenyl)-amino-6,7-dimethoxyquinazoline) and its derivative WHI-P131 inhibited LPS-induced iNOS expression and NO production in a dose-dependent manner. WHI-P154 inhibited the activation of signal transducer and activator of transcription (STAT) 1 and the expression of iNOS mRNA but it had no effect on iNOS mRNA decay when determined by actinomycin D assay. The JAK3 inhibitor had no effect on COX-2 expression, and TNF-alpha production was slightly inhibited only at higher drug concentrations (30 microM). In addition, WHI-P154 inhibited iNOS expression and NO production also in human epithelial cells. Our results suggest that JAK3 inhibition modulates human and murine iNOS expression and NO production in response to inflammatory stimuli.

Tristetraprolin (TTP) is a tandem zinc finger protein that can bind to AU-rich elements (AREs) in the 3'-untranslated regions (3'-UTR) in mRNAs of transiently expressed genes, e.g. tumor necrosis factor-alpha (TNF-alpha) and granulocyte macrophage colony-stimulating factor (GM-CSF). TTP increases the turnover rate of the target mRNAs, thereby reducing, for example, the expression of TNF-alpha and GM-CSF. We examined the role of beta(2)-agonists, cAMP analogs, and forskolin (an activator of adenylate cyclase) on TTP mRNA and protein expression by quantitative real-time RT-PCR and Western blotting in J774 murine macrophages and THP-1 human macrophages. All of these agents increased TTP expression. A nonspecific inhibitor of phosphodiesterases (PDEs) 3-isobutyl-1-methylxanthine (IBMX) and type IV PDE-inhibitor rolipram further enhanced the increase in TTP expression levels, suggesting a cAMP-mediated effect. A possible mediator of these effects is transcription factor activator protein 2 (AP-2), whereas nuclear factor kappaB (NF-kappaB) seemed not to play any role. This mechanism may, at least in part, explain the anti-inflammatory effects which beta(2)-agonists have been reported to have in macrophages.

s / Osteoarthritis and Cartilage 23 (2015) A82eA416 A269 Conclusions: Alkaline phosphatase, BMP-2, and type X collagen production are all characteristic of hypertrophic chondrocytes and may contribute to excess mineralization in OA joints. Taken together, our data suggest that high glucose conditions favor a change towards the hypertrophic phenotype. Ample evidence supports a similar change in human that is characteristic of OA chondrocytes. Our findings are in agreement with the recent clinical studies demonstrating accelerated OA progression in patients with diabetes. The limitations of this study are 1) the hyperglycemic mice were slightly heavier than controls which may add mechanical effects (adipose levels were not measured), and 2) higher noise-to-signal background was present with the type X collagen antibody. These are balanced by the strengths of this study which include 1) animals were verified hyperglycemic prior to DMM, and 2) phenotypic change was tested in two model systems (in vivo rodent and in vitro large mammal). In summary, this study suggests the hypothesis that accelerated hypertrophy of articular chondrocytes is a result of hyperglycemia and may contribute to the progression of OA as previously seen in patients with diabetes. 418 EFFECTS OF FIBROBLAST GROWTH FACTOR-2 AND ITS RECEPTOR ANTAGONISTS IN OSTEOARTHRITIS E. Nummenmaa yz, M. Hamalainen yz, T. Moilanen yx, K. Vuolteenaho yz, E. Moilanen yz. y The Immunopharmacology Res. Group, Univ. of Tampere Sch. of Med., Tampere, Finland; z Tampere Univ. Hosp., Tampere, Finland; xCoxa Hosp. for Joint Replacement, Tampere

Inducible prostaglandin synthase (cyclooxygenase-2, COX-2) is highly expressed in inflammation. The signaling mechanisms involved in the up-regulation of COX-2 are not known in detail. In the present study we investigated the role of c-Jun NH2-terminal kinase (JNK), a member of the mitogen-activated protein kinase (MAPK) family in COX-2 expression and prostaglandin (PG) E2 production in murine J774 macrophages activated by bacterial lipopolysaccharide (LPS). LPS caused a transient activation of JNK which was followed by increased COX-2 expression. Anthra(1,9-cd)pyrazol-6(2H)-one (SP600125), an inhibitor of JNK, inhibited phosphorylation of c-Jun with an IC50 of 5-10 microM. At the same concentrations SP600125 suppressed also LPS-induced COX-2 protein levels and PGE2 production. SP600125 did not alter LPS-induced COX-2 mRNA levels when measured 3 h after addition of LPS, whereas mRNA levels were significantly reduced in SP600125-treated cells when measured 24 h after addition of LPS. LPS-induced COX-2 mRNA levels reduced faster in cells treated with SP600125 than in control cells. Cycloheximide (that is known to activate JNK) enhanced COX-2 expression and its effect was inhibited by SP600125. The present results suggest that JNK pathway is involved in the up-regulation of COX-2 expression possibly by a mechanism related to the stability of COX-2 mRNA.

Background: Reduced eosinophil apoptosis is considered to be a key mechanism for eosinophilia in allergic diseases such as asthma, rhinitis, and eczema. Objective: The aim of our study was to investigate the possible modulatory effect of nitric oxide (NO) in human eosinophils. Methods: Apoptosis in isolated eosinophils was assessed by relative DNA fragmentation assay, annexin-V binding, and morphologic analysis. The activation of c-Jun-N-terminal kinase (JNK) and signal transducer and activator of transcription 5 (STAT5) was assessed by immunoblot analysis. Results: The NO donor S-nitroso- N -acetylpenicillamine (SNAP) reversed the survival-prolonging effect of IL-5 by inducing apoptosis. This effect was blocked by the NO scavenger (2-(4-Carboxyphenyl)-4,4,5,5-tetramethylimidazoline-1-oxyl-3oxide.potassium salt), indicating that reversal of IL-5-mediated eosinophil survival was due to NO. The effect of NO on IL-5-afforded cell survival was not mediated by cyclic guanosine 3′: 5′-monophosphate (cGMP), because neither an inhibitor of guanylyl cyclase nor inhibitors of phosphodiesterases had any effect on SNAP-induced eosinophil apoptosis in IL-5-treated cells. SNAP induced a time-dependent increase in the activity of JNK, and an inhibitor peptide specific for JNK, L-JNKI1, completely reversed SNAP-induced apoptosis in IL-5-treated eosinophils. In contrast, SNAP did not inhibit IL-5-induced STAT5 activation. Inhibition of the activity of caspases by Z-Asp-CH 2 -DCB reversed the effect of SNAP, suggesting that NO promotes apoptosis in IL-5-treated human eosinophils in a caspase-dependent manner. However, this effect of NO was not mediated by means of activation of caspases 3, 8, or 9. Conclusions: Our results suggest that exogenous NO reverses IL-5-mediated eosinophil survival by inducing apoptosis, and this is mediated by means of activation of JNK in a cGMP-independent manner. (J Allergy Clin Immunol 2003;112:93-101.)

Nitric oxide (NO) produced by cartilage and synovial membrane is implicated in the pathogenesis of osteoarthritis (OA) and rheumatoid arthritis (RA). In inflamed joints NO is synthesized in response to proinflammatory cytokines and it is involved in the joint destruction. The aim of the present study was to investigate the effects of TNFalpha-antagonists infliximab and etanercept on NO production in human cartilage.Cartilage specimen obtained from OA patients undergoing knee replacement surgery were studied for iNOS expression and NO production in organ culture to allow intact chondrocyte-matrix interactions. TNFalpha and soluble TNFalpha receptor release was measured by ELISA.Osteoarthritic cartilage produced NO spontaneously and its production was enhanced by proinflammatory cytokines TNFalpha (tumor necrosis factor alpha), IL-1beta (interleukin-1beta), IL-17 (interleukin-17) and by bacterial lipopolysaccharide (LPS). TNFalpha-antagonists infliximab and etanercept inhibited TNFalpha-induced NO production in a dose dependent manner but they had no effect on IL-1beta-, IL-17- and LPS-stimulated NO synthesis. TNFalpha and soluble TNFalpha receptors (sTNFRI and sTNFRII) were produced by human osteoarthritic cartilage. A neutralizing antibody against soluble TNFRI enhanced spontaneous NO production whereas an antibody against soluble TNFRII had no effect.TNFalpha-antagonists infliximab and etanercept suppressed TNFalpha-induced NO production. This effect was not seen on IL-1-, IL-17- or LPS-induced NO production suggesting that TNFalpha is not an autacoid mediator in these processes. The studies with neutralizing antibodies against soluble TNFRI suggest that endogenous cartilage-derived TNFalpha-antagonists modulate NO production in osteoarthritic cartilage.

Objective Nitric oxide (NO) produced by cartilage and synovial membranes is implicated in the pathogenesis of osteoarthritis (OA) and inhibitors of NO synthesis may have indications in the treatment or prevention of joint destruction in OA. Because the signaling mechanisms as well as the NOS isoform involved in induction of NO production in human cartilage remain in many parts unclear, the present study was designed to investigate the regulation of inducible NO synthesis in human intact OA cartilage. Methods Cartilage specimens were collected from OA patients undergoing knee replacement surgery and studied for iNOS expression and NO production in organ culture to allow intact chondrocyte–matrix interactions. J774 macrophages were used for comparison as a well-documented source of iNOS. Results OA cartilage expressed iNOS and produced NO in the absence of exogenous cytokines. Addition of interleukin-1β (IL-1β), tumor necrosis factor α (TNFα) or lipopolysaccharide (LPS) into the culture medium enhanced NO production in a dose-and timedependent manner. Various NOS inhibitors suppressed NO production in the following order of potency: 1400W (novel selective iNOS inhibitor)=L-NIO>L-NMMA>L-NAME. Cycloheximide (an inhibitor of protein synthesis), pyrrolidine dithiocarbamate (PDTC; an NF-κB inhibitor) and genistein (an inhibitor of tyrosine protein kinases) inhibited cytokine-induced NO production, while dexamethasone, diaminohydroxypyrimidine (DAHP; an inhibitor of tetrahydrobiopterin synthesis) and PD 98059 (p42/44 MAP kinase inhibitor) had no effect. Conclusions The results suggest that NO synthesis in human osteoarthritic cartilage derives from the glucocorticoid-insensitive expression of iNOS. Very similar mechanisms appear to regulate inducible NO synthesis in human osteoarthritic cartilage and J774 macrophages with the exception that dexamethasone inhibited NO production in J774 cells but not in osteoarthritic cartilage.

Objective: To investigate the anti-inflammatory and hemodynamic effects of 17β-estradiol in men undergoing elective coronary artery bypass graft surgery (CABG). Design: Prospective, randomized, controlled. Setting: Operating room and intensive care unit in a university hospital. Participants: Twenty-one men undergoing primary, elective CABG surgery. Intervention: 17β-estradiol, 2mg, was given orally twice in 14 hours before the operation. Measurements and Main Results: Leukocyte counts, plasma myeloperoxidase, tumor necrosis factor-α, interleukin (IL)-6, IL-8, and IL-10 were measured perioperatively. Leukocyte counts were lower in the 17β-estradiol group than in controls at 6 hours (11.4 ± 2.0 hours v 15.5 ± 4.7 hours × 109/L) and 20 hours (11.6 ± 1.9 hours v 13.6 ± 2.5 hours × 109/L) after reperfusion (p = 0.03). The release of myeloperoxidase was lower in the 17β-estradiol group than in controls (5 minutes; 634.4 ± 213.1 μg/mL v 773.1 ± 209.3 μg/mL; 4 hours, 305.0 ± 108.0 μg/mL v 441.3 ± 191.6 μg/mL; p = 0.02). Systemic vascular resistance index was lower just after cardiopulmonary bypass, and cardiac index was higher postoperatively in the 17β-estradiol group as compared with controls. Conclusion: Pretreatment with 17β-estradiol can limit leukocyte activation in men after CABG surgery. Copyright © 2001 by W.B. Saunders Company

Earlier data indicate that Lactobacillus rhomnosus GG ATCC 53103 (L. GG), a commensal intestinal bacterial strain, promotes the degradation of proteins in the gut in vivo, and bovine casein hydrolysed with L. GG-derived proteases suppresses lymphocyte proliferation in vitro. The present study aimed to evaluate the effect of L. GG-degraded bovine casein on T-cell activation, i.e. IL-2 mRNA expression and protein kinase C (PKC) translocation. To this end, Northern blot analyses for IL-2 mRNA expression and PKC assays with and without L. GG-degraded casein were carried out on T cells isolated from 11 healthy adults. Cell cultures in 8-11 experiments contained 1 mg ml(-1) bovine casein in degraded or undegraded form in the presence of a mitogen, i.e. phorbol 12,13-dibutyrate plus calcium ionophore (PBDu + A23187) or anti-CD3. Also IL-2, IL-4 and IFN-gamma syntheses were determined in 24-h culture supernatants. IL-2 mRNA expression was reduced in experiments with L. GG-degraded casein. In parallel, the IL-2 concentration in PBDu + A23187-stimulated culture supernatants, expressed as geometric means (95% confidence interval), decreased from 15,892 (7174-35,203) pg ml(-1) to 4744 (2095-10,742) pg ml(-1) when containing L. GG-degraded casein. L. GG-degraded casein inhibited PKC translocation, the action resembling that of PKC inhibitor, RO31-8220. These results extend previous data on L. GG-degraded casein, showing in vitro the suppression of T-cell activation.

Beclomethasone, budesonide, dexamethasone, and fluticasone propionate enhanced human eosinophil apoptosis in a concentration-dependent manner in vitro as assessed by flow cytometric analysis and morphological analysis. The order of potency was fluticasone propionate (EC(50) 3.7+/-1.8 nM) approximately budesonide (EC(50) 5.0+/-1.7 nM)>beclomethasone (EC(50) 51+/-19 nM)>dexamethasone (EC(50) 303+/-40 nM). Hydrocortisone, prednisolone, and prednisone (up to 1 microM) did not induce any significant increase in eosinophil apoptosis. The apoptosis promoting effects of glucocorticoids on eosinophils were reversed by an antagonist of glucocorticoid receptor mifepristone. The survival-prolonging effect of tumor necrosis factor (TNF)-alpha was reversed by dexamethasone and fluticasone (1 microM). In contrast, fluticasone, and dexamethasone (1 microM) did not reverse the survival-prolonging effects of interleukins-3 and -5 or granulocyte-macrophage colony-stimulating factor (GM-CSF). The results suggest that fluticasone and budesonide induce eosinophil apoptosis at clinically achievable drug concentrations via an effect on glucocorticoid receptor.

Eosinophilic inflammation of the airways is a key characteristic of asthma. A defect in apoptosis might contribute to the chronic tissue eosinophilia associated with asthma.Our purpose was to examine whether the rate of apoptosis differs between peripheral blood eosinophils from asthmatic patients and healthy volunteers.Peripheral blood was obtained from volunteers with asthma and from control volunteers. Eosinophils were isolated by CD16-negative selection to99% purity and were cultured for 48 hours. The number of apoptotic eosinophils in the culture was assessed by flow cytometric analysis of relative DNA content in propidium iodide-stained cells. Eosinophil apoptosis is expressed as apoptosis index (number of apoptotic cells/total number of cells).Eosinophils from asthmatic patients not taking steroid medication survived longer (apoptosis index 0.25) than those of healthy control subjects (apoptosis index 0.40, P.05). In contrast, the rate of apoptosis in eosinophils from patients concurrently taking steroids (apoptosis index 0.46) is higher than that of those not using steroids (P.01) and not different from that of healthy subjects. To assess whether endogenous IL-3, IL-5, and GM-CSF production contributes to the delayed eosinophil apoptosis, the effects of the corresponding neutralizing antibodies were studied on eosinophil longevity. Neutralization of GM-CSF, but not of IL-3 or IL-5, increased slightly but significantly (P.01) the rate of apoptosis in eosinophils obtained from patients with asthma. To assess whether beta(2)-agonist medication could contribute to the observed differences, we determined the in vitro effects of albuterol, fenoterol, and salmeterol on eosinophil apoptosis. All beta(2)-agonists inhibited eosinophil apoptosis by 12% to 19%. A possibility existed that a prior in vivo exposure to IL-5, GM-CSF, or beta(2)-agonists would explain the observed difference. To study this, eosinophils were incubated with GM-CSF, IL-5, and albuterol for 2 to 3 hours, followed by washout of the added compounds, and were subsequently cultured for 48 hours. However, an exposure to GM-CSF (7 pmol/L) or IL-5 (10 pmol/L) for 15 to 180 minutes was not a sufficient signal to prevent eosinophil apoptosis. In contrast, exposure to albuterol (100 nmol/L) for 120 minutes was sufficient to induce a significant (P.05) decrease in eosinophil apoptosis.The results suggest that eosinophil apoptosis is delayed in asthma. This delay may be partly explained by production of GM-CSF. The in vitro effects of beta(2)-agonists suggest that beta(2)-agonist use might contribute to the prolonged eosinophil survival through inhibition of apoptosis and thus may worsen eosinophilia in asthmatic patients. Use of inhaled glucocorticoids seems to totally reverse the delayed eosinophil apoptosis in asthma.

The nitric oxide (NO)-, superoxide anion (O2·−)- and peroxynitrite (ONOO−)-releasing properties of 1,2,3,4-oxatriazolium,5-amino-3-(3,4-dichlorophenyl)-chloride (GEA 3162) were characterized and compared with the known NO-donors 3-morpholino-sydnonimine (SIN-1) and S-nitroso-N-acetylpenicillamine. All the three compounds released NO in aqueous solutions in a dose-dependent manner as measured by ozone-chemiluminescence. GEA 3162 produced more NO than SIN-1, but less than S-nitroso-N-acetylpenicillamine during a 45 min incubation time. SIN-1 reduced nitro blue tetrazolium and the effect was inhibitable by superoxide dismutase. Reduction of nitro blue tetrazolium was not detected in the solutions of GEA 3162 and S-nitroso-N-acetylpenicillamine suggesting that SIN-1 but not GEA 3162 and S-nitroso-N-acetylpenicillamine release O2·− in their decomposition process. Formation of ONOO− in solutions of GEA 3162, SIN-1 and S-nitroso-N-acetylpenicillamine was estimated indirectly by measuring the formation of nitrotyrosine. The data indicate that ONOO− was produced in the presence of SIN-1 but not in solutions of GEA 3162 and S-nitroso-N-acetylpenicillamine. The results suggest that GEA 3162 produces negligible amounts of O2·− and ONOO− as compared to SIN-1. This adds the value of GEA 3162 as an useful tool in NO research and could well explain the earlier findings on the superior NO-like biological activity of oxatriazole derivatives as compared to SIN-1.

The effects of novel nitric oxide (NO)-releasing oxatriazole derivatives GEA 3162 and GEA 3175 were studied on cell proliferation and cGMP synthesis in human peripheral blood mononuclear cells stimulated with a lectin mitogen concanavalin A. GEA 3162 (1–30 μM) and GEA 3175 (3–30 μM) inhibited mononuclear cell proliferation in a dose-dependent manner being more potent than the earlier known NO-donor S -nitroso- N -acetylpenicillamine. The inhibitory action was more pronounced when submaximally stimulating concentrations of concanavalin A (0.1 and 1 μg/ml) were used and no inhibition was seen when concanavalin A concentrations were increased up to 10 μg/ml. The antiproliferative concentrations of GEA 3162, GEA 3175 and S -nitroso- N -acetylpenicillamine induced a rapid and transient increase in cGMP production in mononuclear cells cultured in the presence of concanavalin A. Both the antiproliferative action and the increased cGMP production were attenuated when red blood cells were added into the cultures indicating that NO is responsible for both of these actions. An analogue of cGMP, 8-bromo-cGMP (0.1–3 mM) reduced concanavalin A-induced proliferation in a dose-dependent manner suggesting that cGMP may be involved in the antiproliferative action of NO-donors. NO-releasing compounds have immunosuppressive actions which offer therapeutic possibilities and should be kept in mind as potential adverse events when these compounds are used in other indications.

The present work was designed to study the pharmacological control of the receptor-mediated activation of human neutrophils by tolfenamic acid (2(-)[(3-chloro-2-methylphenyl)-amino]benzoic acid). Tolfenamic acid inhibited in a concentration-dependent manner the degranulation response and Ca2+ influx in neutrophils activated either by the chemotactic peptide fMLP (N-formyl-methionyl-leucylphenylalanine) or Ca2+ ionophore A23187 (calcimycin). When fMLP was used to activate neutrophils, tolfenamic acid (30 microM) reduced Ca2+ influx by 50% and degranulation by 20%. A23187-triggered Ca2+ influx and degranulation were inhibited by 60% and 40%, respectively, by 30 microM tolfenamic acid. Tolfenamic acid did not inhibit the release of Ca2+ from intracellular stores induced either by fMLP or A23187. To confirm the inhibition of receptor-mediated cation influx by tolfenamic acid, the agonist induced Mn2+ influx was studied in Ca2+ free medium. Tolfenamic acid (10-30 microM) reduced fMLP-stimulated Mn2+ influx in neutrophils in a concentration-dependent manner. The simultaneous Ca2+ release from intracellular stores was not affected. Protein kinase C activity in sonicated human neutrophils and the purified enzyme from rat brain were inhibited by the protein kinase inhibitor H-7 (1-(5-isoquinolinylsulfonyl)-2-methylpiperazine) but not by tolfenamic acid. Both failed to inhibit neutrophil degranulation induced by phorbol myristate acetate, a protein kinase C activator. Tolfenamic acid (100 microM) increased the cellular cAMP levels up to 1.3-fold in the presence of the phosphodiesterase inhibitor 3-isobutyl-1-methylxanthine. No effects on cellular cGMP levels were found.(ABSTRACT TRUNCATED AT 250 WORDS)

Adrenaline, noradrenaline, isoprenaline, and to a lesser extent dopamine inhibit the release of leukotriene (LT) B 4 from calcium ionophore-stimulated human polymorphonuclear leukocytes, while the release of prostaglandin (PG) E 2 is proportionally elevated. The inactivity of salbutamol, a non-catechol adrenergic β 2 -receptor agonist, and the inability of propranolol to antagonize the effects of adrenaline, suggest the mediation through β-receptor independent mechanisms. Neither are α-1-receptors involved, as prazosin, a specific antagonist, fails to inhibit the reaction. As the principles for biochemical regulation of LT- and PG-production are met by catecholamines in several tissues, the mechanism is considered to be of general physiological importance. Catecholamines may function as coenzymes/antioxidants which, by altering the redox state of the enzyme iron or heme, decrease the LT/ PG ratio thus protecting the organism against tissue anaphylaxis and other LT-related pathophysiology.