Biomedical subjects

M Di Rosa

Publications and source records attributed to M Di Rosa.

At least 19 recordsLinked to original sources

PubMed2006

Chitotriosidase gene expression in Kupffer cells from patients with non-alcoholic fatty liver disease.

BACKGROUND AND AIMS: Non-alcoholic steatohepatitis (NASH) is a clinicopathological condition characterised by a necroinflammatory disorder with fatty infiltration of the hepatocytes. The molecular mechanisms involved in the anomalous behaviour of liver cells have only partially been determined. Human chitotriosidase (Chit) is a chitinolytic enzyme mainly produced by activated macrophages. The aim of this study was to investigate the expression of the chitinase-like gene in Kupffer cells, to determine how chitotriosidase may be implicated in the progression from uncomplicated steatosis to steatohepatitis with progressive fibrosis. METHODS: 75 subjects were studied: 40 with NASH, 20 with simple steatosis, and 15 normal controls. Kupffer cells obtained from liver biopsies were used to detect CHIT expression, superoxide anion (O2-), lipid peroxidation, and tumour necrosis factor alpha (TNFalpha) and ferritin levels. RESULTS: CHIT expression differed markedly in livers from normal controls and in those from patients with simple steatosis or non-alcoholic steatohepatitis. A significant correlation between mRNA CHIT and O2-, lipid peroxidation, TNFalpha, and ferritin levels was observed in both NASH and simple steatosis. CONCLUSIONS: Human Kupffer cells in NASH patients overproduce chitotriosidase. At the highest levels of production, this enzyme may play a role in increasing the risk for a poor outcome in steatohepatitis.

Adult↗

PubMed2005

Interferon-gamma, tumor necrosis factor-alpha, and lipopolysaccharide promote chitotriosidase gene expression in human macrophages.

Human chitotriosidase (Chit), a chitinolytic enzyme, is a member of the chitinase family. In human plasma, Chit activity has been proposed as a biochemical marker of macrophage activation in several lysosomal diseases. Recently we found that Chit activity is higher in patients affected by Plasmodium falciparum malaria infection, suggesting that Chit may reflect induction of an immunological response. To assess this hypothesis, we evaluated the CHIT1 mRNA levels in human monocytes/macrophages (HMMs) following treatment with interferon-gamma (IFNgamma), tumor necrosis factor-alpha (TNFalpha), and lipopolysaccharide (LPS). Stimulation of macrophages with INF-gamma, TNF-alpha, and LPS resulted in an increase in Chit activity as well as the levels of CHIT1 mRNA as measured by quantitative real-time PCR. The data presented in this article show that Chit plays a role in the response to the activation of INF-gamma-, TNF-alpha-, and LPS-driven macrophages, suggesting that the production of Chit by macrophages could have biological relevance in the immune-response.

Gene Expression↗

PubMed2005

Action of prolactin, IFN-gamma, TNF-alpha and LPS on heme oxygenase-1 expression and VEGF release in human monocytes/macrophages.

The pituitary hormone prolactin (PRL) has recently been regarded as a local regulator of macrophage responses. Our goal in this study was to investigate the regulatory interaction between PRL, interferon-gamma (IFN-gamma), tumor necrosis factor-alpha (TNF-alpha) and lipopolysaccharide (LPS) in the heme oxygenase-1 (HO-1) expression and the vascular endothelial growth factor (VEGF) production in human monocytes/macrophages (HMMs). In vitro treatment of HMMs with PRL, IFN-gamma, TNF-alpha and LPS was found to increase both HO-1 expression and protein synthesis in a time-dependent manner. HMMs treated with PRL, IFN-gamma, TNF-alpha and LPS also showed an enhanced release of VEGF. Moreover, co-stimulation of PRL with LPS caused activation of HMMs functions, enhancement of HO-1 expression and induction of VEGF release, whereas addition of PRL inhibited up-regulation of HO-1 or VEGF induced by IFN-gamma or TNF-alpha. Our results demonstrate that PRL, IFN-gamma, TNF-alpha and LPS modulate the expression of angiogenic factors providing additional information about the regulatory mechanism, which controls the angiogenic function of macrophages.

Heme Oxygenase (Decyclizing)↗

PubMed2004

Cloricromene in endotoxemia: role of NF-kappaB.

In this study we investigated, for the first time in vivo, the effect of cloricromene, a cumarine derivative, on NF-kappaB activation in endotoxin-treated rats. Endotoxemia was induced in male rats by the intravenous injection of Salmonella typhosa lipopolysaccharide (LPS; 2 mg/kg/i.v.). In vivo treatment with cloricromene (2 mg/kg/i.v.) 30 min before lipopolysaccharide administration reversed the LPS-induced loss in tone of the aortic rings, improved their reactivity to phenylephrine, decreased both nitric oxide (NO) and TNF-alpha serum levels by inhibiting LPS-induced inducible NO synthase and TNF-alpha mRNA expression, and interestingly inhibited LPS-induced NF-kappaB activation. Our data suggest that cloricromene protects rats from LPS by blocking LPS-induced NF-kappaB activation, leading to inhibition of NO and TNF-alpha overproduction and thereby reversing the LPS-induced vascular hyporeactivity.

Animals↗

PubMed2004

Prolactin induces chitotriosidase gene expression in human monocyte-derived macrophages.

Human chitotriosidase (Chit), a chitinolytic enzyme, is a member of the chitinase family. In human's plasma Chit activity have been proposed as a biochemical marker of macrophage activation in several lysosomal diseases. Recently we found that Chit activity is higher in patients affected by Plasmodium falciparum malaria infection suggesting that chitotriosidase may induce an immunological response. The pituitary hormone prolactin (PRL) is a multifunctional polypeptide also produced by immune cells and represents a key component of the neuroendocrine-immune loop. The presence of PRL receptors in macrophage suggests that PRL is involved in regulating functions in these cells. Our objective in this study was to investigate the effect of PRL in human monocyte-derived macrophages (HMMs) on Chit production. Administration of PRL in HMMs was found to increase both expression and activity of Chit in a time and dose dependent manner as quantified, respectively, by real time PCR and Chit activity assay. PRL-treated monocyte-derived macrophages showed also an enhanced release of superoxide anion (O2-) release. Our observations confirm that PRL regulates HMMs activation and suggest, for the first time, that it influences immune function also through the induction of Chit activity.

Cells, Cultured↗

PubMed2001

Role of cyclopentenone prostaglandins in rat carrageenin pleurisy.

In this study, using rat carrageenin-induced pleurisy, we found that treatment of rats with either indomethacin or NS-398 suppressed the pleurisy at 2 h but significantly exacerbated this reaction at 48 h. Exacerbated inflammation was associated with reduced prostaglandin D(2) levels, decreased heat shock factor 1 (HSF1) activation, reduced hsp72 expression and increased activation of nuclear factor kappaB (NF-kappaB). Replacement of cyclopentenone prostaglandins by treating rats with either prostaglandin J(2) or prostaglandin D(2) reversed the exacerbating effects of cyclooxygenase inhibitors leading to the resolution of the reaction. In conclusion, we demonstrate that cyclopentenone prostaglandins may act as anti-inflammatory mediators by inducing in inflammatory cells HSF1-dependent hsp72 expression and NF-kappaB inhibition, two crucial events for the remission of inflammation.

Active Transport, Cell Nucleus↗

PubMed2001

HSF1/hsp72 pathway as an endogenous anti-inflammatory system.

We investigated the occurrence and the role of HSF1 activation and inducible hsp72 expression in the carrageenin pleurisy in the rat. Molecular analysis performed on pleural cells collected from rat pleural cavity after carrageenin challenge revealed increased HSF1 activation and hsp72 expression. Moreover, local injection of a double-stranded oligodeoxynucleotide (ODN) containing the heat shock element sequence, acting as transcription factor decoy, exacerbated the inflammatory reaction. The exacerbation, induced by wild-type, but not by mutant ODN decoy, was associated to both inhibition of HSF1/DNA binding activity and reduction of hsp72 expression. In conclusion, this study shows that HSF1 activation and hsp72 expression both actually occur in acute inflammation and that the remission of the inflammatory reaction is tightly associated to the HSF1-dependent hsp72 expression, suggesting a a relevant role for the HSF1/hsp72 pathway as an endogenous anti-inflammatory system.

Animals↗

PubMed2001

Structural elucidation of a new cytotoxin isolated from mussels of the Adriatic sea.

A detailed analysis of the toxic composition in the hepatopancreas of mussels from northern Adriatic sea has been performed. Along with some polyether toxins of DSP (diarrhetic shellfish poisoning) type, such as yessotoxin and its analogues, which are responsible for a variety of human seafood poisonings throughout the world, we have now isolated a new type of toxin, the chlorosulfolipid 1, which is completely different in structure from the polyether DSP-toxins isolated so far. The structural determination of the new toxin, including its absolute stereochemistry, has been performed by extensive NMR analysis and molecular mechanics and dynamics calculations.

Animals↗

PubMed2001

Role of nuclear factor-kappaB in a rat model of vascular injury.

In this study we have investigated the relationship between neointima formation and NF-kappaB activation in a model of endothelial denudation of rat carotid artery (balloon angioplasty) using the antioxidant pyrrolidine dithiocarbamate as inhibitor of NF-kappaB activation. Furthermore, we have correlated NF-kappaB activation to the expression of inducible isoforms of both nitric oxide synthase (iNOS) and cyclooxygenase (COX-2) in injured carotids. In control group a significant proliferation of neointima was observed 14 days after balloon angioplasty, which was correlated to an increase of NF-kappaB/DNA binding activity as well as p50/p65 nuclear levels compared to those observed in the carotids from naive or sham-operated rats. Furthermore, NF-kappaB activation was correlated to increased iNOS and COX-2, but not beta-actin, protein expression. Treatment of rats for 14 days with the antioxidant agent pyrrolidine dithiocarbamate (50, 100, 200 mg/kg per os and day) caused a significant inhibition of all the parameters assayed, except beta-actin protein expression. These results indicate that prevention of NF-kappaB activation may lead to the inhibition of neointima formation and suggest that antioxidant agents may have therapeutic relevance for the prevention of human restenosis.

Angioplasty, Balloon↗

PubMed2001

Selective cannabinoid CB1 receptor-mediated inhibition of inducible nitric oxide synthase protein expression in C6 rat glioma cells.

We have studied the effects of two cannabinoid receptor agonists, WIN 55,212-2 and cannabinol, on nitric oxide (NO) production and inducible nitric oxide synthase (iNOS) expression in the C6 glioma cell line. After 24 h of lipopolysaccharide (LPS) (1 microg/mL) and interferon-gamma (IFN-gamma) (300 U/mL) stimulation, a significant increase in NO production, evaluated as nitrite, was observed in the culture medium. WIN 55,212-2 (0.1-10000 nM) and cannabinol (0.3-30000 nM), dose-dependently inhibited nitrite production showing a different potency (WIN 55,212-2 EC(50): 4.2 nM; cannabinol EC(50): 700 nM). WIN 55,212-2 (100 nM), given concomitantly to the stimulus also inhibited iNOS expression but had no effect when added to the cells 2 h after LPS/IFN-gamma, indicating a possible interference at the protein synthesis level or at an earlier step, as gene transcription. The cannabinoid CB1 receptor antagonist, SR141716A (0.1-100 nM), but not the cannabinoid CB2 receptor antagonist, SR144528 (0.1-100 nM), reduced in a dose-related manner WIN 55,212-2-and cannabinol-induced inhibition of nitrite production. SR141161A also reversed the WIN 55,212-2-induced inhibition of iNOS expression. These data suggest that selective cannabinoid CB1 receptor activation, by inhibiting iNOS expression and NO overproduction in glial cells, might be helpful in NO-mediated inflammation leading to neurodegeneration.

Analgesics↗

PubMed2000

Immunostimulant (1 --> 3)-D-glucans from the cell wall of Cryphonectria parasitica (Murr.) Barr strain 263.

A (1 --> 3)-beta-D-glucan with approximately 30% of the residues having a beta-D-Glc-(1 --> 6) branch is the main water-soluble component of the cell wall polysaccharide of Cryphonectria parasitica (Murr.) Barr strain 263. A (1 --> 3)-glucan with both alpha and beta anomeric linkages was found in the water-insoluble polysaccharide fraction. Both fractions possess immunological activity, being able to induce the production of either tumour necrosis factor alpha (TNF-alpha) or nitrite (NO2-).

Adjuvants, Immunologic↗

PubMed2000

Nitric oxide inhibits leucocyte migration in carrageenin-induced rat pleurisy.

OBJECTIVE AND DESIGN: The role of nitric oxide (NO) on leucocyte migration has been investigated in rat carrageenin-induced pleurisy. MATERIAL: Male Wistar rats. TREATMENT: L-arginine, NOC-18 and aminoguanidine were administered subcutaneously 1 h prior to carrageenin injection. METHODS: Leucocyte accumulation into the pleural cavity was measured 4 h after carrageenin challenge. Statistical significance was calculated by Bonferroni test. RESULTS: L-arginine (10 mg/kg) or the NO donor NOC-18 (10 mg/kg), significantly inhibited leucocyte infiltration by 31% and 20% respectively (P<0.01). On the contrary, when these compounds were given at high doses (L-arginine 300 mg/kg; NOC-18 30 mg/kg), leucocyte accumulation was increased by 22% and 33% respectively (P<0.01). Aminoguanidine, a relatively selective inhibitor of the inducible NO synthase, depending on the dose, showed a biphasic effect on cell migration. Thus, at low doses (30 and 100 mg/kg), aminoguanidine increased (by 40% and 74% respectively, P< 0.01) leucocyte infiltration which was inhibited by 41% (P < 0.01) when the drug was given at high dose (300 mg/kg). CONCLUSIONS: These results suggest that in rat carrageenin-induced pleurisy NO primarily inhibits leucocyte migration.

Animals↗

PubMed2000

Cytotoxic saponins from bulbs of Allium porrum L.

An extensive phytochemical analysis of the saponin content has been undertaken on leek, Allium porrum L., sown and collected at different seasons. As a result of this investigation, eight saponins (1-8) have been isolated, four of them (5-8) being novel compounds. Compounds 5 and 6, possessing the same tetrasaccharide moiety of compounds 1 and 3, display very unusual spirostane aglycones, 12-ketoporrigenin and 2,12-diketoporrigenin (named porrigenin C), respectively, recently isolated for the first time as free sapogenin in the same plant. Compounds 7 and 8 are rare cholestane bidesmosides possessing a di- and trisaccharide residues linked to a polyhydroxycholesterol aglycone, respectively. The structures of the isolated compounds have been determined by nondegradative spectroscopic analysis, mainly based on NMR. All the eight saponins isolated from leek were tested for their cytotoxic activity against two different cell lines in vitro, and compounds 1, 2, and 6 resulted particularly active.

Allium↗

PubMed2000

Anti-inflammatory activity of macrolide antibiotics.

The effect of four macrolide antibiotics (roxithromycin, clarithromycin, erythromycin, and azithromycin) on the generation of some mediators and cytokines involved in the inflammatory process has been studied both in vivo and in vitro. Rat carrageenin pleurisy was used as a model of acute inflammation, and the macrolides were administered (10, 20, and 40 mg/kg p.o.) 1 h before the carrageenin challenge. Exudate volume and leukocyte accumulation were both dose-dependently reduced by roxithromycin, clarithromycin and erythromycin in either normal or adrenalectomized animals. Furthermore, in normal rats, prostaglandin (PG)E(2), nitrate plus nitrite, and tumor necrosis factor-alpha levels in pleural exudate were significantly reduced by these macrolides. Roxithromycin appeared more effective than erythromycin and clarithromycin, whereas azithromycin only slightly affected the inflammatory reaction. None of the macrolides were able to modify leukotriene B(4) exudate levels. In vitro experiments have shown that the four macrolides (5-80 microM) reduced in a concentration-dependent manner the production of 6-keto-PGF(1alpha), NO(2)(-), tumor necrosis factor-alpha, interleukin-1beta, and interleukin-6 by lipopolysaccharide-stimulated J774 macrophages. In J774 cells, the inhibition of 6-keto-PGF(1alpha) and NO(2)(-) production by roxithromycin and erythromycin was not dependent on direct inhibition of cyclooxygenase-2 and inducible nitric oxide synthase activity because it appears to be related to the inhibition of cyclooxygenase-2 and inducible nitric oxide synthase protein expression. In conclusion, the present study shows that macrolide antibiotics have anti-inflammatory activity, which likely depends on their ability to prevent the production of proinflammatory mediators and cytokines, and suggest that these agents, particularly roxithromycin, can exert therapeutic effects independently of their antibacterial activity.

6-Ketoprostaglandin F1 alpha↗

PubMed1999

Role of IL-6 in the pleurisy and lung injury caused by carrageenan.

In the present study we used IL-6 knockout mice (IL-6KO) to evaluate the role of IL-6 in the inflammatory response caused by injection of carrageenan into the pleural space. Compared with carrageenan-treated IL-6 wild-type (IL-6WT) mice, carrageenan-treated IL-6KO mice exhibited a reduced degree of pleural exudation and polymorphonuclear cell migration. Lung myeloperoxidase activity and lipid peroxidation were significantly reduced in IL-6KO mice compared with those in IL-6WT mice treated with carrageenan. Immunohistochemical analysis for nitrotyrosine and poly(A)DP-ribose polymerase revealed a positive staining in lungs from carrageenan-treated IL-6WT mice. No positive staining for nitrotyrosine or PARS was found in the lungs of the carrageenan-treated IL-6KO mice. Staining of lung tissue sections obtained from carrageenan-treated IL-6WT mice with an anti-cyclo-oxygenase-2 Ab showed a diffuse staining of the inflamed tissue. Furthermore, expression of inducible nitric oxide synthase was found mainly in the macrophages of the inflamed lungs from carrageenan-treated IL-6WT mice. The intensity and degree of the staining for cyclo-oxygenase-2 and inducible nitric oxide synthase were markedly reduced in tissue sections obtained from carrageenan-treated IL-6KO mice. Most notably, the degree of lung injury caused by carrageenan was also reduced in IL-6KO mice. Treatment of IL-6WT mice with anti-IL-6 (5 microg/day/mouse at 24 and 1 h before carrageenan treatment) also significantly attenuated all the above indicators of lung inflammation. Taken together, our results clearly demonstrate that IL-6KO mice are more resistant to the acute inflammation of the lung caused by carrageenan injection into the pleural space than the corresponding WT mice.

Animals↗

PubMed1999

Inhibition of nuclear factor-kappaB prevents the loss of vascular tone in lipopolysaccharide-treated rats.

We studied the role of nuclear factor-kappaB (NF-kappaB) on the tone and on the expression of inducible nitric oxide (NO) synthase, both evaluated in aortas from lipopolysaccharide-treated rats. Thoracic aorta rings from lipopolysaccharide-treated rats (4 mg/kg, i.p.), compared to those from naive animals, showed: (i) reduced contractility to phenylephrine, (ii) progressive loss in tone when contracted with phenylephrine, (iii) increased inducible NO synthase protein expression and NF-kappaB activation. Pyrrolidine dithiocarbamate (10, 30, 100 mg/kg, i.p.), an antioxidant inhibitor of NF-kappaB activation, dose dependently suppressed all these lipopolysaccharide-induced effects. These results demonstrate that in vivo inhibition of NF-kappaB activation prevented the lipopolysaccharide-induced loss of vascular tone, an effect which was correlated to reduced expression of inducible NO synthase protein.

Animals↗

PubMed1999

Glycolipids from sponges. VII. Simplexides, novel immunosuppressive glycolipids from the Caribbean sponge Plakortis simplex.

The new glycolipids simplexides (1) have been isolated from the marine sponge Plakortis simplex, and their structure determined by spectroscopic data and microgram-scale chemical degradation. Simplexides are composed of long-chain secondary alcohols glycosylated by a disaccharide chain, and represent a new structural kind of glycolipids. Simplexides strongly inhibit proliferation of activated T-cells by a non-cytotoxic mechanism and can be regarded as simple model molecules for designing immunosuppressive drugs.

Animals↗

PubMed1999

Cyclooxygenase-2-dependent generation of 8-epiprostaglandin F2alpha by lipopolysaccharide-activated J774 macrophages.

OBJECTIVE: The generation of 8-epiprostaglandin F2alpha (8-epi-PGF2alpha) by arachidonic acid (AA)- and lipopolysaccharide (LPS)- stimulated J774 macrophages has been investigated. MATERIAL: Murine monocyte/macrophage J774 cell line. METHODS: Cells were incubated with AA or LPS and the amount of 8-epi-PGF2alpha, 6-ketoprostaglandin F1alpha (6-keto-PGF1alpha) and prostaglandin E2 (PGE2) released in the incubation media measured by radioimmunoassay (RIA) or, in some experiments, by enzyme immunoassay (EIA). The effect of dexamethasone (DXM), cycloheximide (CXM) and 5,5 dimethyl-3-(3-fluorophenyl)-4-(4-methylsulfonyl)phenyl-2(5H)-furanone (DFU), a cyclooxygenase-2 (COX-2) selective inhibitor, on LPS-induced generation of AA metabolites was assessed. RESULTS: AA induced a significant production of 6-ketoPGF1alpha and PGE2, whereas LPS caused a concentration- and time-dependent increase of 8-epi-PGF2alpha, 6-keto-PGF1alpha and PGE2. DXM (2 microM) as well as CXM (1 microM) significantly decreased (p<0.001; n = 4) the LPS-stimulated production of 8-epi-PGF2alpha (by 86% and 82%, respectively), 6-ketoPGF1alpha (by 78% and 74%, respectively) and PGE2 (by 83% and 78%, respectively). Immunostimulated production of AA metabolites was also inhibited by DFU (IC50 0.3+/-0.04 microM; 0.16 +/- 0.02 microM and 0.11 +/- 0.05 microM for 8-epi-PGF2alpha, 6-keto-PGF1alpha and PGE2, respectively. CONCLUSIONS: These results demonstrate the role of COX-2 in the generation of 8-epi-PGF2alpha by LPS-stimulated J774 macrophages. The relevance of these findings requires further elucidation.

6-Ketoprostaglandin F1 alpha↗