The CO-releasing molecule CORM-2 is a novel regulator of the inflammatory process in osteoarthritic chondrocytes.

OBJECTIVES: Previous work has shown that the CO-releasing molecule CORM-2 protects against cartilage degradation. The aim of this study was to examine whether CORM-2 can control the production of inflammatory mediators in osteoarthritic chondrocytes and determine the mechanisms involved. METHODS: Primary cultures of chondrocytes from OA patients were stimulated with IL-1beta. The production of reactive oxygen species, nitrite, PGE(2), TNF-alpha and IL-1 receptor antagonist (IL-1Ra) were measured in the presence or absence of CORM-2. The expression of nitric oxide synthase-2 (NOS-2), cyclo-oxygenase-2 (COX-2) and microsomal PG E synthase-1 (mPGES-1) was followed by western blot and real-time PCR. Activation of nuclear factor-kappaB (NF-kappaB) and hypoxia inducible factor-1alpha (HIF-1alpha), and phosphorylation of NF-kappaB inhibitory protein alpha (IkappaBalpha) were determined by ELISA. RESULTS: CORM-2 decreased the production of oxidative stress, nitrite and PGE(2). In addition, CORM-2 inhibited IL-1beta-induced TNF-alpha but enhanced IL-1Ra production. Treatment of chondrocytes with CORM-2 strongly down-regulated NOS-2 and mPGES-1 protein expression, whereas COX-2 was reduced to a lesser extent. These changes were accompanied by a significant decrease in mRNA expression for NOS-2 and mPGES-1. CORM-2 showed a concentration-dependent inhibition of DNA-binding activity for p65 NF-kappaB and HIF-1alpha. IkappaBalpha phosphorylation was also reduced by CORM-2 treatment. CONCLUSIONS: These data have opened new mechanisms of action for CORM-2, raising the prospect that CO-releasing molecules are an interesting strategy for the development of new treatments in articular conditions.

[Primary hyperparathyroidism: current role of bone densitometry]. / Hiperparatiroidismo primario. Papel actual de la densitometría ósea.

OBJECTIVE: To describe the usefulness of bone densitometry in the diagnosis and follow-up of patients with primary hyperthyroidism (PHPT). MATERIAL AND METHODS: Retrospective review of 48 patients with PHPT; 27 received surgical treatment and 21 medical treatment. Radiologic and biochemical findings and bone mass were evaluated at the start of the study and after one and two years. RESULTS: All patients had elevated PTH levels and 87% had normal or moderately increased calcemia. The most common clinical presentations were renal colic (34%) and the absence of symptoms (22.8%). The sensitivity of scintigraphy was 75% and the sensitivity of ultrasonography was 12%. We found osteopenia in 70.3% of patients and osteoporosis in 81.3%, fundamentally in the radius and spine. Bone mass at one year and at two years remained similar in the femur (73.8%) and spine (81.8%) in 58% and 50% of the patients, respectively. Increased bone mass was seen in the femur (30.4%) in 13.6% of the patients and in the spine (33.3%) in 50% of the patients. This increase was greater in the group that received surgical treatment. Calcemia and PTH were decreased by 69.2% and 76.9 %, respectively, in the patients that underwent surgery. In the group that received medical treatment, calcemia remained similar and PTH was decreased by 50%. Fractures developed in 21.8% of the patients. CONCLUSIONS: Densitometry assesses the repercussions of the disease on bone mass at the start of treatment and after treatment. Osteoporosis is a common finding. Gains in bone mass occurred fundamentally in patients that had undergone surgery. Bone mass remained similar in a high percentage of patients in both groups.

Treatment with a CO-releasing molecule (CORM-3) reduces joint inflammation and erosion in murine collagen-induced arthritis.

OBJECTIVE: CO-releasing molecules (CO-RMs) are a novel class of anti-inflammatory agents. We have examined the possible therapeutic effects of CORM-3 in collagen-induced arthritis (CIA). METHODS: Arthritis was induced in DBA-1/J mice by type II collagen. Animals were treated with CORM-3 (5 and 10 mg/kg/day, intraperitoneally) or the inactive compound iCORM-3 (10 mg/kg/day, intraperitoneally) unable to release CO, from days 22 to 31. Production of anti-type II collagen antibodies, cytokines and cartilage olimeric matrix protein (COMP) was evaluated by enzyme-linked immunosorbent assay, and prostaglandin E(2) (PGE(2)) by radioimmunoassay. Localisation of cyclooxygenase-2 (COX-2), haem oxygenase-1 (HO-1), intercellular adhesion molecule-1 (ICAM-1) and receptor activator of nuclear factor kappaB ligand (RANKL) was examined by immunohistochemistry. RESULTS: Therapeutic administration of CORM-3 suppressed clinical and histopathological manifestations of disease. The levels of PGE(2), interleukin (IL)1beta, IL2, IL6, IL10 and tumour necrosis factor (TNF)alpha in joint tissues were inhibited by CORM-3. By contrast, CORM-3 augmented IL4. Anti-type II collagen antibodies and COMP levels in serum were reduced by CORM-3. Treatment with CORM-3 decreased cellular infiltration, joint inflammation and destruction, as well as the expression of COX-2, ICAM-1 and RANKL, whereas HO-1 increased. These beneficial effects were due to CO release, as iCORM-3 was ineffective. CONCLUSION: This study reveals the antiarthritic properties of CORM-3 in the CIA model and supports the notion that CO-RMs could be developed as a novel strategy for the treatment of inflammatory and arthritic conditions.

Evaluation of the anti-inflammatory and analgesic activity of Me-UCH9, a dual cyclooxygenase-2/5-lipoxygenase inhibitor.

Recently, we reported the dual inhibition of cyclooxygenase-2 (COX-2) and 5-lipoxygenase (5-LO) activity by some phenylsulphonyl urenyl chalcone derivatives. 2,4-dichloro-4'N[N'(4''methylphenylsulphonyl)urenyl] chalcone (Me-UCH9), was selected in the present study to determine its potential anti-inflammatory and analgesic effect after oral administration in several animal models related to the activation of COX-2 and 5-LO pathways. In the zymosan stimulated mouse air pouch model, Me-UCH9, reduced in a dose-dependent manner leukotriene B(4) (LTB(4)) levels in pouch exudates obtained at 4 h, as well as prostaglandin E(2) (PGE(2)) generated through COX-2 activation at 24 h. Tumor necrosis factor alpha (TNF-alpha) and myeloperoxidase activity were also strongly inhibited in this model. Me-UCH9 significantly reduced granuloma size and vascular index determined in the murine air pouch granuloma model of angiogenesis. In the carrageenan-induced paw edema, this compound inhibited inflammatory response and pain, as well as PGE(2) and LTB(4) content in paw edematous fluid. Analgesic properties were corroborated in the murine phenyl-p-benzoquinone-induced writhing test. Finally, Me-UCH9 exerted anti-inflammatory effects in the chronic model of rat adjuvant-induced arthritis, both inhibiting paw swelling and reducing PGE(2) content. Our findings confirm that Me-UCH9 can modulate inflammatory and nociceptive responses in relation to the dual inhibition of COX-2 and 5-LO activities presented by this compound.

The carbon monoxide-releasing molecule CORM-2 inhibits the inflammatory response induced by cytokines in Caco-2 cells.

BACKGROUND AND PURPOSE: Recent evidence indicates that carbon monoxide-releasing molecules (CO-RMs) exhibit potential anti-inflammatory properties. In the present study, we have investigated whether tricarbonyl dichloro ruthenium(II) dimer (CORM-2) can control the inflammatory response induced by cytokines in a human colonic epithelial cell line, Caco-2. EXPERIMENTAL APPROACH: Caco-2 cells were preincubated with CORM-2 for 30 minutes and then stimulated with interleukin (IL)-1beta, tumor necrosis factor-alpha and interferon-gamma for different times. Gene expression was analyzed by real-time PCR. Protein expression was investigated by Western blot and ELISA. Transcription factor activation was determined by the luciferase method. KEY RESULTS: We have shown that CORM-2 significantly decreased the mRNA expression of nitric oxide synthase-2 (NOS-2) and the production of nitrite, in Caco-2 cells stimulated with cytokines. IL-8, IL-6 and metalloproteinase-7 (MMP-7) mRNA and protein were also significantly reduced by CORM-2. Time-course and small interfering RNA studies suggest that inhibition of IL-6 plays a role in the regulation of MMP-7 expression by CORM-2. These effects of CORM-2 can be dependent on the modulation of nuclear factor-kappaB (NF-kappaB), activator protein-1, CCAT/enhancer binding protein and the phosphorylated forms of NF-kappaB inhibitory protein-alpha, c-Jun N-terminal protein kinase 1/2, p38 and extracellular signal-regulated kinase 1/2. CONCLUSIONS AND IMPLICATIONS: CORM-2 can regulate a number of genes relevant in intestinal inflammation and cancer progression. These findings provide new insights into the anti-inflammatory properties and potential applications of this class of compounds.

Storage stability of ketones on carbon adsorbents.

Activated coconut carbon constitutes the more widely used sorbent for preconcentration of volatile organic compounds in sampling workplace air. Water vapour is always present in the air and its adsorption on the activated carbon surface is a serious drawback, mainly when sampling polar organic compounds, such as ketones. In this case, the recovery of the compounds diminishes; moreover, ketones can be decomposed during storage. Synthetic carbons contain less inorganic impurities and have a lower capacity for water adsorption than coconut charcoal. The aim of this work was to evaluate the storage stability of various ketones (acetone, 2-butanone, 4-methyl-2-pentanone and cyclohexanone) on different activated carbons and to study the effect of adsorbed water vapour under different storage conditions. The effect of storage temperature on extraction efficiencies was significant for each ketone in all the studied sorbents. Recovery was higher when samples were stored at 4 degrees C. The results obtained for storage stability of the studied ketones showed that the performance of synthetic carbons was better than for the coconut charcoals. The water adsorption and the ash content of the carbons can be a measure of the reactive sites that may chemisorb ketones or catalize their decomposition. Anasorb 747 showed good ketone stability at least for 7 days, except for cyclohexanone. After 30-days storage, the stability of the studied ketones was excellent on Carboxen 564. This sorbent had a nearly negligible ash content and the adsorbed water was much lower than for the other sorbents tested.

Phenylsulphonyl urenyl chalcone derivatives as dual inhibitors of cyclo-oxygenase-2 and 5-lipoxygenase.

Two series of phenylsulphonyl urenyl chalcone derivatives (UCH) with various patterns of substitution were tested for their effects on nitric oxide (NO) and prostaglandin E2 (PGE2) overproduction in RAW 264.7 macrophages. None of the tested compounds reduced NO production more than 50% at 10 microM but most of them inhibited the generation of PGE2 with IC50 values under the micromolar range. Me-UCH 1, Me-UCH 5, Me-UCH 9, Cl-UCH 1, and Cl-UCH 9 were selected to evaluate their influence on human leukocyte functions and eicosanoids generation. These derivatives selectively inhibited cyclo-oxygenase-2 (COX-2) activity in human monocytes being Me-UCH 5 the most potent (IC50 0.06 microM). Selected compounds also reduced leukotriene B4 synthesis in human neutrophils by a direct inhibition of 5-lipoxygenase (5-LO) activity, with IC50 values from 0.5 to 0.8 microM. In addition, lysosomal enzyme secretion, such as elastase or myeloperoxidase as well as superoxide generation in human neutrophils were also reduced in a similar range. Our findings indicate that UCH derivatives exert a dual inhibitory effect on COX-2/5-LO activity. The profile and potency of these compounds may have relevance for the modulation of the inflammatory and nociceptive responses with reduction of undesirable side-effects associated with NSAIDs.

Effects of heme oxygenase-1 inducers on established rat adjuvant arthritis.

Heme oxygenase-1 (HO-1) activity can inhibit inflammatory and immune responses. We have examined the influence of HO-1 induction on the established rat adjuvant arthritis model of chronic inflammation. Therapeutic administration of cobalt protoporphyrin IX (CoPP; 5 mg/kg/day i.p.) from day 17 to 23 significantly reduced the inflammatory response, with partial inhibition of hind paw edema and the production of some inflammatory mediators such as nitric oxide metabolites and tumor necrosis factor-alpha, although joint erosion was observed. Hemin administration (26 mg/kg/day i.p.) during the same time period was ineffective on these parameters. Western blot analysis of hind paw homogenates revealed a weaker induction of HO-1 by this compound in comparison with CoPP. Our data indicate that pharmacological HO-1 induction after the establishment of adjuvant arthritis partially reduced the inflammatory response but it was not sufficient to control joint erosion in our experimental conditions.

Epstein-Barr virus positivity in primary vaginal lymphoma.

BACKGROUND: Primary non-Hodgkin lymphoma (NHL) of the vagina is a rare location. Its association with the Epstein-Barr virus (EBV) has been only reported in another case. We present a new case, emphasizing the oncogenetic relevance of EBV. CASE REPORT: A 45-year-old woman with a pelvic pain revealed in her vaginal inspection a thick and hard vaginal plug with a "paving stone" appearance. The biopsy reported a vaginal non-Hodgkin lymphoma type B of intermediate cell, with positive result for EBV. After treatment, a complete remission was obtained. CONCLUSION: The EBV is the main responsible for the non-Hodgkin lymphoma; classified as a group I carcinogen, it has been associated with a variety of neoplastic tumors, although it is unusual with extranodal type B diffuse lymphoma.

A new chloroquinolinyl chalcone derivative as inhibitor of inflammatory and immune response in mice and rats.

The synthetic chalcone derivative 1-(2,4-dichlorophenyl)-3-(3-(6,7-dimethoxy-2-chloroquinolinyl))-2-propen-1-one (ClDQ) was evaluated for its anti-inflammatory, analgesic and immunomodulatory efficacy in-vitro and in-vivo. ClDQ concentration-dependently inhibited the production of nitric oxide (NO) (IC50 4.3 microM) and prostaglandin E(2) (PGE(2)) (IC50 1.8 microM) in RAW 264.7 macrophages stimulated with lipopolysaccharide. Human mononuclear cell proliferation was significantly inhibited by 10 microM ClDQ. Oral administration of ClDQ (10-30 mg kg(-1)) in the 24-h zymosan-stimulated mouse air-pouch model produced a dose-dependent reduction of cell migration as well as NO and PGE(2) levels in exudates. ClDQ (20 mg kg(-1), p.o.) inhibited ear swelling and leucocyte infiltration in the delayed-type hypersensitivity response to 2,4-dinitrofluorobenzene in mice. In the rat adjuvant-arthritis model, this compound reduced joint inflammation as well as PGE(2) and cytokine levels. In addition, ClDQ displayed analgesic effects in the phenylbenzoquinone-induced abdominal constriction model in mice and in the late phase of the nociceptive response to formalin. Our findings indicated the potential interest of ClDQ in the modulation of some immune and inflammatory conditions.

Anti-inflammatory actions of the heme oxygenase-1 pathway.

Heme oxygenase 1 (HO-1) is induced by oxidative or nitrosative stress, cytokines and other mediators produced during inflammatory processes, likely as part of a defence system in cells exposed to stress to provide a negative feedback for cell activation and the production of mediators, which could modulate the inflammatory response. HO-1 activity results in the inhibition of oxidative damage and apoptosis, with significant reductions in inflammatory events including edema, leukocyte adhesion and migration, and production of inflammatory cytokines. HO-1 is induced by nitric oxide (NO) in different biological systems and can control the increased production of this mediator observed in many inflammatory situations. Regulatory interactions between HO-1 and cyclooxygenase (COX) pathways have also been reported. Modulation of signal transduction pathways by HO-1 or products derived from its activity, such as carbon monoxide (CO), may mediate the anti-inflammatory effects of this protein. Regulation of HO-1 activity may be a therapeutical strategy for a number of inflammatory conditions.

1-(2,3,4-trimethoxyphenyl)-3-(3-(2-chloroquinolinyl))-2-propen-1-one, a chalcone derivative with analgesic, anti-inflammatory and immunomodulatory properties.

OBJECTIVE AND DESIGN: The synthetic chalcone derivative 1-(2,3,4-trimethoxyphenyl)-3-(3-(2-chloroquinolinyl))-2-propen-1-one (TQ) was evaluated for its immunomodulatory and anti-inflammatory efficacy in vitro and in vivo. MATERIAL AND SUBJECTS: Human neutrophils and lymphocytes from healthy volunteers and RAW 264.7 murine macrophages. Swiss mice and Lewis rats were randomly divided into groups of six animals. TREATMENT: TQ was orally administered in all in vivo assays (10-30 mg/kg). METHODS: Elastase, superoxide and LTB(4) release were assayed in human neutrophils, NO/PGE(2) production and NF-kappaB activation in RAW 264.7, and (3)H thymidine incorporation in human lymphocytes. Zymosan-stimulated air pouches, DNFB-DTH, PBQ-induced writhings and formalin-induced pain were assayed in mice. Adjuvant-induced arthritis was tested in rats. Dunnett's t-test was employed for statistical analysis. RESULTS: Human T-cell proliferation, neutrophil functions and NO/PGE(2) production in murine macrophages were inhibited by TQ (IC(50) in the microM range), which showed anti-inflammatory, immunomodulatory and analgesic effects. CONCLUSIONS: Our findings indicate the potential interest of TQ in the modulation of some immune and inflammatory responses probably by NF-kappaB inhibition.

The nitric oxide related therapeutic phenomenon: a challenging task.

Nitric oxide (NO), produced from L-arginine by the activity of constitutive and inducible NO synthases, has been implicated in a wide range of physiological and pathophysiological processes. Low concentrations of this mediator play homeostatic roles, whereas NO is up-regulated in a number of pathological states and can have damaging effects. Pharmacological modulation of NO levels or NO biosynthesis may be a therapeutic strategy for a number of conditions, although the reported results can be some times controversial. Inhibitors of NO synthases exhibit different selectivity for the neuronal, endothelial or inducible isoforms, which contributes to their beneficial and detrimental effects. Recent developments in this field may offer an alternative for the treatment of inflammatory disorders, pain, neurological diseases, shock, atherosclerosis or cancer.

Inhibition of acute and chronic inflammatory responses by the hydroxybenzoquinonic derivative rapanone.

Rapanone (2,5-dihydroxy-3-tridecyl-1,4-benzoquinone), a natural compound isolated from Myrsine guianensis growing in the Andean highlands of Colombia, was studied in different in vitro and in vivo models as a potential antioxidant and anti-inflammatory drug. Rapanone showed a mild anti-lipoperoxidative profile in rat liver microsomes and inhibited potently degranulation (IC(50) of 9.8 microM) and superoxide chemiluminescence (IC(50) of 3.0 microM) in human neutrophils. In addition, rapanone is a selective and potent human synovial PLA(2) inhibitor (IC(50) of 2.6 microM). In vivo experiments using the carrageenan paw oedema and the zymosan air pouch model in mice as well as the adjuvant arthritis model in rats have proved that rapanone is very efficient in controlling the inflammatory process by different administration routes.

Effect of some hexahydroimidazo[1,2-c]pyrimidines in inflammatory responses involving leucocytes and macrophages.

We have studied the effects of some hexahydroimidazo[1,2-c]pyrimidine derivatives (HIPs) on leucocyte functions in-vitro and we have assayed the anti-inflammatory activity of these compounds in two models of inflammation. All HIPs inhibited the human neutrophil degranulation process and superoxide generation at concentrations in the microM range. In mouse peritoneal macrophages stimulated with lipopolysaccharide, HIP-4 and HIP-5 inhibited nitrite production without affecting prostaglandin E2 (PGE2) accumulation. HIP-4 was also active in the zymosan-injected mouse air pouch model (at 100 nmol/pouch), with significant reductions in leucocyte migration and PGE2 and leukotriene B4 levels in the air pouch exudate. To confirm the anti-inflammatory effects of this compound, we tested HIP-4 orally (10-40 mg kg(-1)) on carrageenan mouse-paw oedema where it exerted a dose-dependent inhibition of paw swelling with significant reductions of myeloperoxidase and elastase activity and PGE2 levels in paw homogenates. This study demonstrates that some HIPs inhibit leucocyte functions and one of these derivatives (HIP-4) shows anti-inflammatory activity when administered by the oral route, which can be related to inhibition of leucocyte migration.

[Lymphadenomegaly in patients with chronic liver disease]. / Linfadenomegalias en pacientes con hepatopatía crónica.

Abdominal lymphadenomegaly is a frequent ultrasonographic finding in patients with chronic liver disease. Its clinical significance is not well understood. The aim of this study was to determine the relationship between this finding and several characteristics of liver disease in 44 patients with chronic liver disease (79.5% due to hepatitis C virus). To do this, all patients underwent simultaneous liver biopsy and abdominal ultrasonography, in which the number and localization of the enlarged abdominal lymph nodes were confirmed. Viral load in patients with chronic hepatitis C virus infection was determined. No significant differences were found in serum hepatitis C RNA concentrations between patients who presented lymphadenomegaly and those who did not. However, the presence of lymphadenomegaly was associated with greater histological activity. If this finding were confirmed in studies with larger samples, the presence of ultrasonographically-detected enlarged abdominal lymph nodes in patients with chronic liver disease due to hepatitis C virus infection would indicate more severe histological lesions.

Inhibition of leukocyte functions by the alkaloid isaindigotone from Isatis indigotica and some new synthetic derivatives.

The alkaloid isaindigotone (1a) and seven derivatives have been synthesized to study their influence on several leukocyte functions and the generation of inflammatory mediators. Isaindigotone (1a) was found to be a scavenger of superoxide generated either by the hypoxanthine/xanthine oxidase system or stimulated human neutrophils. Isaindigotone (1a) and its acetylated derivative (1b) also inhibited 5-lipoxygenase activity and leukotriene B(4) production in these cells, whereas none of the compounds affected degranulation. In RAW 264.7 macrophages stimulated with lipopolysaccharide, synthetic derivatives exerted higher inhibitory effects on prostaglandin E(2) (PGE(2)) and nitric oxide (NO) generation when compared with (1a). The presence of an acetoxyl group at C-4' favors the inhibition of NO and PGE(2) production, whereas the fluoro substituent at C-4' or the absence of substituents on the aromatic ring of the benzylidene unit improves the inhibition of PGE(2). Thus, this series of compounds can attenuate the production of mediators relevant to the inflammatory response.

Effect of imidazo[1,2-a]pyrimidine derivatives on leukocyte function.

OBJECTIVE AND DESIGN: A series of six imidazo[1,2-a]pyrimidine (IP) derivatives were evaluated for their effects on leukocyte functions in vitro as well as on the inflammatory response induced by zymosan in the mouse air pouch. MATERIALS AND SUBJECTS: Human neutrophils and murine peritoneal macrophages were used for in vitro assays. Mouse air pouch was performed in Swiss mice. TREATMENT: Test compounds were incubated with either human neutrophils or mouse peritoneal macrophages at concentrations not showing cytotoxic effects. For in vivo experiments, IPs were injected into the air pouch. METHODS: Elastase and myeloperoxidase release, superoxide generation and LTB4 production were assayed in human neutrophils treated with different stimuli. Mouse peritoneal macrophages were stimulated with lipopolysaccharide (LPS), followed by determination of nitrite and PGE2 levels in supernatants. Zymosan was injected into six days-old mouse air pouches. Dunnett's t-test was employed for statistical analysis. RESULTS: All IPs inhibited human neutrophil degranulation with IC50 values in the microM range. IP-1, IP-2 and IP-5 also decreased superoxide generation. In LPS-stimulated macrophages, IP-4 and IP-6 inhibited nitrite production with a moderate reduction in PGE2 generation. In addition, these two compounds at 100 nmol/pouch inhibited leukocyte migration and LTB4 levels in the exudate of the mouse air pouch. CONCLUSIONS: Imidazo[1,2-a]pyrimidines are a class of compounds with antiinflammatory potential.

Modulation of haem oxygenase-1 expression by nitric oxide and leukotrienes in zymosan-activated macrophages.

Phagocytosis of unopsonized zymosan by RAW 264.7 macrophages upregulated protein expression of haem oxygenase-1 (HO-1), inducible nitric oxide synthase (iNOS) and cyclo-oxygenase-2 (COX-2) in a time- and concentration-dependent manner. In the presence of zymosan, exogenous prostaglandin E(2) (PGE(2)) did not exert significant effects on the expression of these three enzymes. In contrast, exogenous leukotriene B(4) (LTB(4)) and LTC(4) in the nanomolar range inhibited HO-1 and iNOS expression, as well as nitrite accumulation. The COX inhibitors indomethacin and NS398 weakly inhibited HO-1 expression but had no effect on iNOS and COX-2 expression or nitrite. In contrast, the 5-lipoxygenase (5-LO) inhibitor ZM 230,487 significantly decreased HO-1, iNOS and nitrite, which were not affected by zileuton. Dexamethasone showed an inhibitory effect on HO-1 expression induced by zymosan. ZM 230,487 but not zileuton, inhibited the shift due to nuclear factor-kappaB (NF-kappaB), whereas they did not modify activator protein-1 (AP-1) binding. Our results suggest that inhibition of NF-kappaB binding could mediate the effects of ZM 230,487 on the modulation of HO-1 and iNOS protein expression. NOS inhibition by L-N(G)-nitroarginine methyl ester (L-NAME) or 1400 W abolished nitrite production and strongly reduced HO-1 expression. These results show an induction of HO-1 protein expression by zymosan phagocytosis in macrophages, with a positive modulatory role for endogenous NO and a negative regulation by exogenous LTs, likely dependent on the reduction of iNOS expression and NO production.

Heme oxygenase-1 induction by nitric oxide in RAW 264.7 macrophages is upregulated by a cyclo-oxygenase-2 inhibitor.

Unstimulated RAW 264.7 macrophages express negligible heme oxygenase-1 (HO-1) protein but incubation with the nitric oxide (NO) donor spermine nonoate (SPNO) induced HO-1 and weakly cyclo-oxygenase-2 (COX-2) protein. This effect was potentiated by coincubation with the COX-2 selective inhibitor, SC58125. Cells incubated with SPNO showed a strong increase in HO-1 mRNA levels after 4 h with a significant potentiation in the presence of SC58125, which did not modify HO-1 mRNA stability. The induction of HO-1 by NO and its potentiation by anti-inflammatory agents may play a role in inflammatory and immune responses.