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In this study, a sterile and biocompatible chitosan (CHI) gel for wound healing applications was formulated. CHI powder was treated in autoclave (ttCHI) to prepare sterile formulations. The heat treatment modified the CHI molecular weight, as evidenced by GPC analysis, and its physical-chemical features. Differential scanning calorimetry studies indicated that the macromolecules, before and after thermal treatment, differ in the strength of water-polymer interaction leading to different viscoelastic and flow properties. Thermally treated CHI exhibited the following effects: (i) increased the proliferation and migration of human foreskin foetal fibroblasts at 24 h; (ii) accelerated wound healing (measured as area of lesion) at 3 and 10 days in an in vivo model of pressure ulcers. These effects were linked to the increase of the hydroxyproline and haemoglobin content as well as Wnt protein expression. Moreover, we found a reduction of myeloperoxidase activity and TNF-α mRNA expression. These observations suggest the potential of this novel CHI gel in wound healing and other therapeutic applications. [ABSTRACT FROM AUTHOR]

Several diseases are characterized by chronic inflammation, a condition frequently associated with angiogenesis and fibrogenesis that account for the development of granulation tissue. Nuclear Factor kappa-light-chain-enhancer of activated B cells (NF-κB) is a crucial modulator of intracellular prosurvival signaling pathways and is implicated in the pathogenesis of inflammatory process. In this study, we have investigated the role of NF-κB in the angiogenic and fibrogenic response induced by λ-carrageenin in a rat model of chronic inflammation at 1, 3, and 5 days. The subcutaneous implant of λ-carrageenin-soaked sponges in rat induced a time-related increase of granulation tissue formation accompanied by intense neovascularization. These λ-carrageenin-induced changes were significantly reduced by coinjection of wild-type oligodeoxynucleotide (WT ODN) decoy to NF-κB. Molecular, morphological, and ultrastructural analysis performed on whole granulation tissue demonstrated: (1) inhibition of NF-κB/DNA binding activity; (2) downregulation of cyclooxygenase-2, matrix metalloproteinase-9, tumor necrosis factor-α, and vascular endothelial growth factor; (3) upregulation of thrombospondin (TSP)-1 at 1 day and TSP-2 at 5 days; and (4) increase in Bax to Bcl-2 ratio. Our findings show that the blockade of NF-κB activation by WT ODN decoy prevents the development of granulation tissue induced by λ-carrageenin-soaked sponge implant upregulating Bax as well as TSP-1 and TSP-2 expression. [ABSTRACT FROM AUTHOR]

Multiple cellular stressors, including activation of the tumour suppressor p53, can stimulate autophagy. Here we show that deletion, depletion or inhibition of p53 can induce autophagy in human, mouse and nematode cells subjected to knockout, knockdown or pharmacological inhibition of p53. Enhanced autophagy improved the survival of p53-deficient cancer cells under conditions of hypoxia and nutrient depletion, allowing them to maintain high ATP levels. Inhibition of p53 led to autophagy in enucleated cells, and cytoplasmic, not nuclear, p53 was able to repress the enhanced autophagy of p53−/− cells. Many different inducers of autophagy (for example, starvation, rapamycin and toxins affecting the endoplasmic reticulum) stimulated proteasome-mediated degradation of p53 through a pathway relying on the E3 ubiquitin ligase HDM2. Inhibition of p53 degradation prevented the activation of autophagy in several cell lines, in response to several distinct stimuli. These results provide evidence of a key signalling pathway that links autophagy to the cancer-associated dysregulation of p53. [ABSTRACT FROM AUTHOR]

Chronic inflammation is often associated with granuloma formation that is a hallmark of many human diseases. The transcription factor nuclear factor-kappa B (NF-κB) plays a central role in this process by regulating the expression of several pro-inflammatory genes. Cannabinoids (CBs) from Cannabis sativa L. exert a large number of biological effects including anti-inflammatory and anti-angiogenic effects. In this study, we investigated the role of CBs on granuloma formation induced by λ-carrageenin-soaked sponge implant in rat. Our results show that local administration of WIN 55,212-2, a CB1/CB2 agonist, given daily or at time of implantation significantly decreased weight and neo-angiogenesis in granuloma tissue and inhibited nuclear factor-kappa B (NF-κB)/DNA binding that was associated with a reduced inducible nitric oxide synthase (iNOS), cyclooxygenase 2 (COX-2), tumor necrosis factor alpha (TNF-α), and vascular endothelial growth factor (VEGF) messenger RNA (mRNA) and protein expression. Also, arachidonyl-2-chloroethylamide (ACEA), a CB1 selective agonist, and JWH-015, a CB2 selective agonist, exhibited the same effects that were reversed by SR141716-A and SR144528, respectively, CB1 and CB2 selective antagonists. These results indicate that CBs given locally may represent a potential therapeutic tool in controlling chronic inflammation avoiding psychotropic effects. [ABSTRACT FROM AUTHOR]

Alzheimer’s disease (AD) is the most common age-related neurodegenerative disorder. A massive accumulation of β-amyloid (Aβ) peptide aggregates has been proposed as pivotal event in AD. Aβ-induced toxicity is accompanied by a variegated combination of events including oxidative stress. The Wnt pathway has multiple actions in the cascade of events triggered by Aβ, and drugs that rescue Wnt activity may be considered as novel therapeutics for AD treatment. Cannabidiol, a non-psychoactive marijuana component, has been recently proposed as an antioxidant neuroprotective agent in neurodegenerative diseases. Moreover, it has been shown to rescue PC12 cells from toxicity induced by Aβ peptide. However, the molecular mechanism of cannabidiol-induced neuroprotective effect is still unknown. Here, we report that cannabidiol inhibits hyperphosphorylation of tau protein in Aβ-stimulated PC12 neuronal cells, which is one of the most representative hallmarks in AD. The effect of cannabidiol is mediated through the Wnt/β-catenin pathway rescue in Aβ-stimulated PC12 cells. These results provide new molecular insight regarding the neuroprotective effect of cannabidiol and suggest its possible role in the pharmacological management of AD, especially in view of its low toxicity in humans. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) plays an important role in the pathogenesis of celiac disease. We have examined the involvement of nuclear factor-κB (NF-κB), interferon regulatory factor-1 (IRF-1), and signal transducer and activator of transcription-1α (STAT-1α) on the synergistic induction of inducible nitric oxide synthase (iNOS) gene expression by gliadin (G) in association with interferon-γ (IFN-γ) in RAW 264.7 macrophages. We found that IFN-γ was efficient in enhancing the basal transcription of the iNOS promoter at 1, 6, and 24 h, whereas G had no effect. The G plus IFN-γ association caused an increase in iNOS promoter activity which was inhibited by pyrrolidine dithiocarbammate (PDTC) at 6 and 24 h as well as by genistein (Gen) and tyrphostine B42 (TB42) at 1 h, inhibitors of NF-κB, IRF-1, and STAT-1α activation, respectively. Similarly, the IFN-γ and G combination treatment led to a higher increase in iNOS mRNA levels at 1, 6, and 24 h compared with IFN-γ alone. Gen and TB42 inhibited iNOS mRNA levels at 1 h, whereas PDTC inhibited iNOS mRNA levels at 6 and 24 h. In addition, the synergistic induction of iNOS gene expression by G plus IFN-γ correlated with the induction of NF-κB, IRF-1, and STAT-1α/DNA binding activity and mRNA expression. In conclusion, our study, which provides evidence that the effect of G on iNOS gene transcription in IFN-γ-stimulated RAW 264.7 cells can be ascribed to all three transcription factors, may contribute to lead to new insights into the molecular mechanisms governing the inflammatory process in celiac disease. [ABSTRACT FROM AUTHOR]

We investigated the effect of hydroxytyrosol (HT), a phenolic compound from virgin olive oil, on inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression in J774 murine macrophages stimulated with lipopolysaccharide (LPS). Incubation of cells with LPS caused an increase in iNOS and COX-2 mRNA and protein level as well as ROS generation, which was prevented by HT. In addition, HT blocked the activation of nuclear factor-κB (NF-κB), signal transducer and activator of transcription-1α (STAT-1α) and interferon regulatory factor-1 (IRF-1). These results, showing that HT down-regulates iNOS and COX-2 gene expression by preventing NF-κB, STAT-1α and IRF-1 activation mediated through LPS-induced ROS generation, suggest that it may represent a non-toxic agent for the control of pro-inflammatory genes. [ABSTRACT FROM AUTHOR]

Nitric oxide (NO) plays an important role in the pathogenesis of the histological changes seen in coeliac disease. We have investigated the effect of peptic-tryptic digest of gliadin (Pt-G) and gliadin (G) on inducible nitric oxide synthase (iNOS) protein expression in RAW 264.7 macrophages stimulated with interferon-γ (IFN-γ). Pt-G and G enhanced in a concentration and time-dependent manner NO production by IFN-γ-stimulated RAW 264.7 cells. The increase of iNOS protein expression was correlated with NF-κB/DNA binding activity and occurred at transcriptional level. Pyrrolidine dithiocarbamate and N-α-para-tosyl-L-lysine chloromethyl ketone, two known inhibitors of NF-κB activation, decreased significantly NO production and iNOS protein expression as well as NF-κB/DNA binding activity. Our results show that the effect of Pt-G and G on enhancement of iNOS protein expression in IFN-γ-treated RAW 264.7 cells is mainly mediated through NF-κB and suggest that blockage of NF-κB activation reduces enhancing effect of gluten on NO production in inflamed mucosa of coeliac patients. [ABSTRACT FROM AUTHOR]

NF-κB regulates inflammatory and immune response by increasing the expression of specific genes. In celiac disease proinflammatory cytokines, adhesion molecules, and enzymes whose gene expression is known to be regulated by NF-κB are involved. This study investigated the activation of NF-κB in inflamed mucosa from patients with untreated celiac disease. Biopsy specimens from control, untreated, and treated patients were subjected to molecular biology analysis. NF-κB activation was evaluated by electrophoretic mobility shift assay. NF-κB related subunit protein level, and inducible nitric oxide synthase and cyclo-oxygenase 2 protein expression was analyzed by western blot. Both NF-κB/DNA binding activity and p50/p65 nuclear levels were higher in biopsy specimens from untreated patients than in those from treated patients and controls. The degradation of IκBβ in the cytosol and the reappearance in the nucleus indicated a persistent NF-κB activation in celiac disease. NF-κB activity was maintained in cultured biopsy specimens up to 6 h and decreased at 24 h, and then the addition of peptic-tryptic digest of gliadin caused the recovery of NF-κB activity at 6 h. NF-κB/DNA binding activity was correlated with inducible nitric oxide synthase and cyclo-oxygenase-2 protein expression. These results show for the first time that NF-κB is activated in the inflamed mucosa of celiac patients and suggest that it may represent a molecular target for the modulation of inflammatory response in celiac disease. [ABSTRACT FROM AUTHOR]

In the present study we investigated in the reverse passive Arthus reaction elicited in the rat skin the anti-inflammatory effect of double-stranded oligodeoxynucleotides (ODN) with consensus nuclear factor-κB (NF-κB) sequence as transcription factor decoys (TFD) to inhibit NF-κB binding to native DNA sites. Local administration of wild-type-, but not mutant-decoy ODN, dose-dependently reduced both plasma leakage and neutrophil infiltration in rat skin. Molecular analysis performed on soft tissue obtained from rat skin demonstrated: (1) an inhibition of NF-κB/DNA binding activity; (2) a decreased nuclear level of p50 and p65 NF-κB subunits; (3) an inhibition of cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) protein expression, two inflammatory enzymes transcriptionally controlled by NF-κB. Furthermore, SN-50, a cell-permeable peptide capable of inhibiting the nuclear translocation of NF-κB complexes, as well as ammonium pyrrolidine dithiocarbamate, an inhibitor of NF-κB activation, exhibited a similar profile of activity of decoy ODN. Our results indicate that decoy ODN, acting as an in vivo competitor for the transcription factor's ability to bind to cognate recognition sequence, may represent a novel strategy to modulate immune reactions. [ABSTRACT FROM AUTHOR]

In this study we have investigated the relationship between neointima formation and NF-κB activation in a model of endothelial denudation of rat carotid artery (balloon angioplasty) using the antioxidant pyrrolidine dithiocarbamate as inhibitor of NF-κB activation. Furthermore, we have correlated NF-κB 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-κB/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-κB activation was correlated to increased iNOS and COX-2, but not β-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 β-actin protein expression. These results indicate that prevention of NF-κB activation may lead to the inhibition of neointima formation and suggest that antioxidant agents may have therapeutic relevance for the prevention of human restenosis. [ABSTRACT FROM AUTHOR]

Stimulation of J774 macrophages with lipopolysaccharide (LPS) leads to the release of large amounts of prostaglandins (PGs) generated by the inducible isoform of cyclooxygenase (COX-2). Nitric oxide (NO), a pleiotropic free radical, has been demonstrated to modulate the release of a broad range of inflammatory mediators, amongst these PGs. In the present study we investigated the molecular mechanism by which NO affects cyclooxygenase pathway. Incubation of J774 cells with LPS caused an increase of prostaglandin E2 production and COX-2 protein expression which was prevented in a concentration-dependent fashion by pre-incubating cells with sodium nitroprusside (SNP) and S-nitroso-gluthatione (GSNO), two NO-generating agents. Electrophoretic mobility shift assay indicated that both NO-generating agents blocked LPS-induced activation of nuclear factor-κB (NF-κB) by increasing IκB-α protein expression and blocking nuclear translocation of NF-κB subunits p50 and p65. SNP and GSNO also inhibited nuclear factor-interleukin-6 (NF-IL6) activation. These results show for the first time that SNP and GSNO down-regulate LPS-induced COX-2 expression by inhibiting NF-κB and NF-IL6 activation and suggest a negative feed-back mechanism that may be important for limiting excessive or prolonged PGs production in pathological events. [ABSTRACT FROM AUTHOR]