Diagnostic potential of NETosis-derived products for disease activity, atherosclerosis and therapeutic effectiveness in Rheumatoid Arthritis patients

OBJECTIVES

1) To assess the association of NETosis and NETosis-derived products with the activity of the disease and the development of cardiovascular disease in RA; 2) To evaluate the involvement of NETosis on the effects of biologic therapies such as anti-TNF alpha (Infliximab) and anti-IL6R drugs (Tocilizumab).

METHODS

One hundred and six RA patients and 40 healthy donors were evaluated for the occurrence of NETosis. Carotid-intimae media thickness was analyzed as early atherosclerosis marker. Inflammatory and oxidative stress mediators were quantified in plasma and neutrophils. Two additional cohorts of 75 RA patients, treated either with Infliximab (n = 55) or Tocilizumab (n = 20) for six months, were evaluated.

RESULTS

NETosis was found increased in RA patients, beside myeloperoxidase and neutrophil elastase protein levels. Cell-free nucleosomes plasma levels were elevated, and strongly correlated with the activity of the disease and the positivity for autoantibodies, alongside inflammatory and oxidative profiles in plasma and neutrophils. Moreover, ROC analyses showed that cell-free nucleosomes levels could identify RA patients showing early atherosclerosis with high specificity. RA patients treated either with IFX or TCZ for six months exhibited decreased generation of NETs. Concomitantly, clinical parameters and serum markers of inflammation were found reduced. Mechanistic in vitro analyses showed that inhibition of NETs extrusion by either DNase, IFX or TCZ, further abridged the endothelial dysfunction and the activation of immune cells, thus influencing the global activity of the vascular system.

CONCLUSIONS

NETosis-derived products may have diagnostic potential for disease activity and atherosclerosis, as well as for the assessment of therapeutic effectiveness in RA.

'Atherothrombosis-associated microRNAs in Antiphospholipid syndrome and Systemic Lupus Erythematosus patients'

MicroRNAs markedly affect the immune system, and have a relevant role in CVD and autoimmune diseases. Yet, no study has analyzed their involvement in atherothrombosis related to APS and SLE patients. This study intended to: 1) identify and characterize microRNAs linked to CVD in APS and SLE; 2) assess the effects of specific autoantibodies. Six microRNAs, involved in atherothrombosis development, were quantified in purified leukocytes from 23 APS and 64 SLE patients, and 56 healthy donors. Levels of microRNAs in neutrophils were lower in APS and SLE than in healthy donors. Gene and protein expression of miRNA biogenesis-related molecules were also reduced. Accordingly, more than 75% of identified miRNAs by miRNA profiling were underexpressed. In monocytes, miR124a and -125a were low, while miR-146a and miR-155 appeared elevated. Altered microRNAs’ expression was linked to autoimmunity, thrombosis, early atherosclerosis, and oxidative stress in both pathologies. In vitro treatment of neutrophils, monocytes, and ECs with aPL-IgG or anti-dsDNA-IgG antibodies deregulated microRNAs expression, and decreased miRNA biogenesis-related proteins. Monocyte transfections with pre-miR-124a and/or -125a caused reduction in atherothrombosis-related target molecules. In conclusion, microRNA biogenesis, significantly altered in neutrophils of APS and SLE patients, is associated to their atherothrombotic status, further modulated by specific autoantibodies.

Nitric oxide and cancer: the emerging role of S-nitrosylation

Nitric oxide (NO˙) is a short-lived, endogenously produced gas that is highly diffusible across cell membranes and acts as a signaling molecule in the body. The redox state and chemistry of NO˙ facilitate its interaction with various proteins thus regulating various intracellular and intercellular events. One of the key mechanisms by which NO˙ regulates the function of various target proteins is through the coupling of a nitroso moiety from NO-derived metabolites to a reactive cysteine leading to the formation of a S-nitrosothiol (SNO), a process commonly known as S-nitrosylation. S-nitrosylation signaling events within the cell have led to the discovery of many other physiological functions of NO˙ in many other types of cells including cancer cells. Only recently are the diverse roles of S-nitrosylation in cancer beginning to be understood. In the present review we discuss the recent evidence for the diverse roles of NO˙/SNO-related mechanisms in cancer biology and therapy, including the participation of NO˙ in the pathogenesis of cancer, its duality in protecting against or inducing cancer cell death and the contribution of NO˙ to metastatic processes. In addition, NO˙ can be therapeutically used in the reversal of tumor cell resistance to cytotoxic drugs and as a sensitizing agent to chemo- and radiotherapy. Finally, recent studies providing evidence for NO-related mechanisms of epigenetic gene expression regulation will also be discussed. Undoubtedly, new exciting results will contribute to this rapidly expanding area of cancer research.

Treatment of Refractory Cholestatic Pruritus With Molecular Adsorbent Recirculating System (MARS)

Pruritus is a common complication of cholestatic liver diseases or liver graft dysfunction. Current medical therapies lack efficacy. The molecular adsorbent recirculating system (MARS) represents an interesting therapeutic option. Our objective was to report our experience in the management of four patients with intractable pruritus with MARS.

PATIENTS AND METHODS

The MARS treatment cycle included three consecutive treatments, each of 8 hours duration. The four patients with intractable pruritus who were treated had primary biliary cirrhosis/autoimmune hepatitis overlap syndrome (n = 1), ductopenic allograft rejection (n = 2), or posttransplant cholestatic HCV recurrence (n = 1). Intensity of pruritus was documented 24 hours before as well as 24 hours, 7 and 30 days after MARS therapy, and at the end of follow-up. We measured complete blood cell counts, glucose, BUN, creatinine, sodium, potassium, AST, ALT, GGT, alkaline phosphatase, bilirubin, prothrombin activity, and activated partial thromboplastin time.

RESULTS

MARS therapy was well tolerated. Patient 1 experienced temporal relief of pruritus, but needed another MARS cycle because of relapse. Patient 2 experienced partial and temporary relief of pruritus, was listed for retransplantation, and received a liver graft 2 months later. Patient 3 showed a dramatic reduction in the degree of pruritus with MARS. Pruritus in patient 4 decreased promptly with MARS therapy and conversion of immunosuppression to tacrolimus, thereby avoiding retransplantation.

CONCLUSION

MARS therapy is a promising, safe therapeutic option to treat refractory pruritus caused by cholestatic liver disorders.

Rapid induction of NF-kappaB binding during liver cell isolation and culture: inhibition by L-NAME indicates a role for nitric oxide synthase

This study is the first to demonstrate activation of NF-kappaB binding just 10 minutes into the commonly employed hepatocyte isolation procedure. It is further reported that the anti-oxidant Trolox can prevent the induction of NF-kappaB during the well established hepatocyte isolation procedure but not during their subsequent culture. However both phases of NF-kappaB activation are inhibited by L-NAME intimating a role for NO production, via nitric oxide synthase. These findings demonstrate that at least 2 different signal transduction pathways are operative during hepatocyte isolation and culture. Thus further studies employing Trolox and L-NAME will help delineate how each pathway contributes to the generalised loss of liver function commonly observed in vitro.

Formation of 8-oxoguanine in cellular DNA of Escherichia coli strains defective in different antioxidant defences

This paper examines the relationship in Escherichia coli between the in vivo content of 8-oxoguanine (8-oxoG) in chromosomal DNA and deficiencies of various key antioxidant defences. The structural genes for catalases (katG and katE), cytosolic superoxide dismutases (sodA and sodB) or formamidopyrimidine-DNA glycosylase (fpg) were inactivated to obtain bacterial strains lacking the scavenger enzymes for H2O2 or O2.- or the DNA repair protein for 8-oxoG. Wild-type bacteria showed 5-fold increased sensitivity to both lethality and mutagenesis by H2O2 in K medium (1% casamino acids and 1% glucose), as compared with nutrient broth. This higher sensitivity was associated with increased chromosomal oxidative damage, estimated as the 8-oxodG content, and with a marked decrease in both catalase and SOD activities. Bacteria lacking both cytosolic SODs (sodA sodB mutant) displayed increased 8-oxodG content in chromosomal DNA (2.8-fold that of the wild-type) when grown under standard aerated conditions. Comparatively, no significant difference in 8-oxodG content was observed in cells grown without aeration. Bacteria totally devoid of catalase activity (katG katE mutant) showed wild-type contents of 8-oxodG in chromosomal DNA when grown under aerated conditions. Nevertheless, the protective role of catalase in preventing formation of 8-oxodG in chromosomal DNA became evident under oxidative stress conditions: growth under hyperoxygenation and, particularly, following H2O2 exposure. Catalase deficiency resulted in a dramatic decrease in viability after H2O2 exposure. A deficiency of Fpg protein also sensitized E.coli to H2O2 lethality, though to lesser extent than a deficiency of catalase activity. However, the scavenger enzyme and the DNA repair protein protected equally against 8-oxoG formed in vivo upon H2O2 treatment.

Rapid determination of glutathione status in fish liver using high-performance liquid chromatography and electrochemical detection

A rapid and sensitive method for the detection of reduced (GSH), oxidised (GSSG) and protein-bound (PSSG) glutathione in fish liver, using reversed-phase HPLC with electrochemical detection has been developed. Separation was carried out isocratically at room temperature using 0.020 M sodium phosphate, pH 2.7 as mobile phase. A series dual-channel electrochemical detector was used for the simultaneous determination of GSH and GSSG. PSSG was determined after reduction by 1,4-dithiothreitol. The detection limits found for a 3:1 signal-to-noise ratio were 16.2 and 8.1 pmol for GSH and GSSG, respectively. The results obtained demonstrate that this method could be useful for measurement of the glutathione redox status in fish liver and are consistent with those reported for other fish. The method has been applied to follow the oxidative stress induced in vivo by copper(II) ions in the gilthead seabream fish (Sparus aurata). At longer times after copper(II) injection, the glutathione redox status of the exposed fish returned to a more reduced state, suggesting the existence of adaptive processes.