Characterization of macrophage phenotype, redox, and purinergic response upon chronic treatment with methionine and methionine sulfoxide in mice.

Hypermethioninemia is a disorder characterized by high plasma levels of methionine (Met) and its metabolites such as methionine sulfoxide (MetO). Studies have reported associated inflammatory complications, but the mechanisms involved in the pathophysiology of hypermethioninemia are still uncertain. The present study aims to evaluate the effect of chronic administration of Met and/or MetO on phenotypic characteristics of macrophages, in addition to oxidative stress, purinergic system, and inflammatory mediators in macrophages. In this study, Swiss male mice were subcutaneously injected with Met and MetO at concentrations of 0.35-1.2 g/kg body weight and 0.09-0.3 g/kg body weight, respectively, from the 10th-38th day post-birth, while the control group was treated with saline solution. The results revealed that Met and/or MetO induce an M1/classical activation phenotype associated with increased levels of tumor necrosis factor alpha and nitrite, and reduced arginase activity. It was also found that Met and/or MetO alter the activity of antioxidant enzymes superoxide dismutase, catalase, and glutathione peroxidase, as well as the levels of thiol and reactive oxygen species in macrophages. The chronic administration of Met and/or MetO also promotes alteration in the hydrolysis of ATP and ADP, as indicated by the increased activity of ectonucleotidases. These results demonstrate that chronic administration of Met and/or MetO promotes activated pro-inflammatory profile by inducing M1/classical macrophage polarization. Thus, the changes in redox status and purinergic system upon chronic Met and/or MetO exposure may contribute towards better understanding of the alterations consistent with hypermethioninemic patients.

Tannic acid elicits selective antitumoral activity in vitro and inhibits cancer cell growth in a preclinical model of glioblastoma multiforme.

Glioblastoma is a devastating tumor affecting the central nervous system with infiltrative capacity, high proliferation rate and chemoresistance. Therefore, it is urgent to find new therapeutic alternatives that improve this prognosis. Herein, we focused on tannic acid (TA) a polyphenol with antioxidant and antiproliferative activities. In this work, the antitumor and antioxidant effects of TA on rat (C6) glioblastoma cells and their cytotoxicity relative to primary astrocyte cultures were evaluated in vitro. Cells were exposed to TA of 6.25 to 75 µM for 24, 48 and/or 72 h. In addition, colony formation, migration and cell adhesion were analyzed and flow cytometry was used to analyze cell death and cell cycle. Next, the action of TA was evaluated in a preclinical glioblastoma model performed on Wistar rats. In this protocol, the animals were treated with a dose of 50 mg/kg/day TA for 15 days. Our results demonstrated that TA induced in vitro selective antiglioma activity, not demonstrating cytotoxicity in astrocyte culture. It induced cell death by apoptosis and cell cycle arrest, reducing formation and size of colonies, cell migration/adhesion and showing to be a potential antioxidant. Interestingly, the antiglioma effect was also observed in vivo, as TA decreased tumor volume by 55%, accompanied by an increase in the area of intratumoral necrosis and infiltration of lymphocytes without causing systemic damage. To the best of our knowledge, this is the first study to report TA activity in a GBM preclinical model. Thus, this natural compound is promising as a treatment for glioblastoma.

Synthesis of thiazolidin-4-ones and thiazinan-4-ones from 1-(2-aminoethyl)pyrrolidine as acetylcholinesterase inhibitors.

The present study describes the synthesis of a novel series of thiazolidin-4-one and thiazinan-4-one using 1-(2-aminoethyl)pyrrolidine as amine precursor. All compounds were synthesised by one-pot three component cyclocondensation reaction from the amine, a substituted benzaldehyde and a mercaptocarboxylic acid. The compounds were obtained in moderate to good yields and were identified and characterised by 1H, 13 C, 2 D NMR and GC/MS techniques. The compounds also were screened for their in vitro acetylcholinesterase (AChE) activity in hippocampus and cerebral cortex on Wistar rats. The six most potent compounds have been investigated for their cytotoxicity by cell viability assay of astrocyte primary culture, an important cell of central nervous system. We highlighted two compounds (6a and 6k) that had the lowest IC50 in hippocampus (5.20 and 4.46 µM) and cerebral cortex (7.40 and 6.83 µM). These preliminary and important results could be considered a starting point for the development of new AChE inhibitory agents.

Methionine and methionine sulfoxide treatment induces M1/classical macrophage polarization and modulates oxidative stress and purinergic signaling parameters.

Methionine is an essential amino acid involved in critical metabolic process, and regulation of methionine flux through metabolism is important to supply this amino acid for cell needs. Elevation in plasma methionine commonly occurs due to mutations in methionine-metabolizing enzymes, such as methionine adenosyltransferase. Hypermethioninemic patients exhibit clinical manifestations, including neuronal and liver disorders involving inflammation and tissue injury, which pathophysiology is not completely established. Here, we hypothesize that alterations in macrophage inflammatory response may contribute to deleterious effects of hypermethioninemia. To this end, macrophage primary cultures were exposed to methionine (1 mM) and/or its metabolite methionine sulfoxide (0.5 mM), and M1/proinflammatory or M2/anti-inflammatory macrophage polarization was evaluated. In addition, inflammation-related pathways including oxidative stress parameters, as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) activities; reactive oxygen species (ROS) production, and purinergic signaling, as ATP/ADP/AMPase activities, were investigated. Methionine and/or methionine sulfoxide induced M1/classical macrophage activation, which is related to proinflammatory responses characterized by increased iNOS activity and TNF-α release. Further experiments showed that treatments promoted alterations on redox state of macrophages by differentially modulated SOD and CAT activities and ROS levels. Finally, methionine and/or methionine sulfoxide treatment also altered the extracellular nucleotide metabolism, promoting an increase of ATPase/ADPase activities in macrophages. In conclusion, these findings contribute to better understand the participation of proinflammatory responses in cell injury observed in hypermethioninemic patients.

Preparation, characterization and antitumor activity of a cationic starch-derivative membrane embedded with a ß-cyclodextrin/curcumin inclusion complex.

A membrane of cationic starch-derivative/poly(vinyl alcohol) was prepared and utilized as a support to immobilize a ß-cyclodextrin/curcumin inclusion complex. The resulting material (denote as ß-CD/CUR-MBN) was characterized in detail by different techniques. In vitro experiments revealed that ß-CD/CUR-MBN enables the controlling of the curcumin release process, which is guided by the relaxation of the polymer matrix. Moreover, cytotoxic assays were performed to investigate the effect of ß-CD/CUR-MBN on two cancer cell lines (melanoma and glioblastoma). The results showed that the polymeric membrane exerts higher cytotoxicity against these cells than free curcumin. Also, ß-CD/CUR-MBN exerted a prolonged cytotoxic effect (up to 96 h), even using a low concentration (50 µg mL-1), indicating that the curcumin in the polymeric membrane showed increased bioavailability under the tested condition. ß-CD/CUR-MBN was non-cytotoxic against normal cells suggesting a specific action of this material against target cancer cells. The results reported here allow ranks ß-CD/CUR-MBN as a promising biomaterial to act as a local drug delivery system to treat cancer.