Evaluation interaction of graphene oxide with heparin for antiviral blockade: a study of ab initio simulations, molecular docking, and experimental analysis.

CONTEXT: Heparin, one of the drugs reused in studies with antiviral activity, was chosen to investigate a possible blockade of the SARS-CoV-2 spike protein for viral entry through computational simulations and experimental analysis. Heparin was associated to graphene oxide to increase in the binding affinity in biological system. First, the electronic and chemical interaction between the molecules was analyzed through ab initio simulations. Later, we evaluate the biological compatibility of the nanosystems, in the target of the spike protein, through molecular docking. The results show that graphene oxide interacts with the heparin with an increase in the affinity energy with the spike protein, indicating a possible increment in the antiviral activity. Experimental analysis of synthesis and morphology of the nanostructures were carried out, indicating heparin absorption by graphene oxide, confirming the results of the first principle simulations. Experimental tests were conducted on the structure and surface of the nanomaterial, confirming the heparin aggregation on the synthesis with a size between the GO layers of 7.44 Å, indicating a C-O type bond, and exhibiting a hydrophilic surface characteristic (36.2°). METHODS: Computational simulations of the ab initio with SIESTA code, LDA approximations, and an energy shift of 0.05 eV. Molecular docking simulations were performed in the AutoDock Vina software integrated with the AMDock Tools Software using the AMBER force field. GO, GO@2.5Heparin, and GO@5Heparin were synthesized by Hummers and impregnation methods, respectively, and characterized by X-ray diffraction and surface contact angle.

Açaí (Euterpe oleracea Mart.) presents anti-neuroinflammatory capacity in LPS-activated microglia cells.

INTRODUCTION: Neuropsychiatric diseases are responsible for one of the highest burden of morbidity and mortality worldwide. These illnesses include schizophrenia, bipolar disorder, and major depression. Individuals affected by these diseases may present mitochondrial dysfunction and oxidative stress. Additionally, patients also have increased peripheral and neural chronic inflammation. The Brazilian fruit, açaí, has been demonstrated to be a neuroprotective agent through its recovery of mitochondrial complex I activity. This extract has previously shown anti-inflammatory effects in inflammatory cells. However, there is a lack of understanding of potential anti-neuroinflammatory mechanisms, such as cell cycle involvement. OBJECTIVE: The objective of this study is to evaluate the anti-neuroinflammatory potential of an açaí extract in lipopolysaccharide-activated BV-2 microglia cells. METHODS: Açaí extract was produced and characterized through high performance liquid chromatography. Following açaí extraction and characterization, BV-2 microglia cells were activated with LPS and a dose-response curve was generated to select the most effective açaí dose to reduce cellular proliferation. This dose was then used to assess reactive oxygen species (ROS) production, double-strand DNA release, cell cycle modulation, and cytokine and caspase protein expression. RESULTS: Characterization of the açaí extract revealed 10 bioactive molecules. The extract reduced cellular proliferation, ROS production, and reduced pro-inflammatory cytokines and caspase 1 protein expression under 1 µg/mL in LPS-activated BV-2 microglia cells but had no effect on double strand DNA release. Additionally, açaí treatment caused cell cycle arrest, specifically within synthesis and G2/Mitosis phases. CONCLUSION: These results suggest that the freeze-dried hydroalcoholic açaí extract presents high anti-neuroinflammatory potential.

Açaí (Euterpe oleracea Mart.) as a Potential Anti-neuroinflammatory Agent: NLRP3 Priming and Activating Signal Pathway Modulation.

Neurological disorders have been demonstrated to be associated with mitochondrial dysfunction. This impairment may lead to oxidative stress and neuroinflammation, specifically promoted by NLRP3 expression. Açaí (Euterpe oleracea Mart.) has been studied in this field, since it presents important biological activities. We investigated açaí extract's anti-neuroinflammatory capacity, through NLRP3 inflammasome modulation. Microglia (EOC 13.31) were exposed to LPS and nigericin, as agents of inflammatory induction, and treated with açaí extract. Additionally, we used lithium (Li) as an anti-inflammatory control. Three different experiment models were conducted: (1) isolated NLRP3 priming and activation signals; (2) combined NLRP3 priming and activation signals followed by açaí extract as a therapeutic agent; and (3) combined NLRP3 priming and activation signals with açaí extract as a preventive agent. Cells exposed to 0.1 µg/mL of LPS presented high proliferation and increased levels of NO, and ROS, while 0.1 µg/mL of açaí extract was capable to reduce cellular proliferation and recover levels of NO and ROS. Primed and activated cells presented increased levels of NLRP3, caspase-1, and IL-1ß, while açaí, Li, and orientin treatments reversed this impairment. We found that açaí, Li, and orientin were effective prophylactic treatments. Preventative treatment with Li and orientin was unable to avoid overexpression of IL-1ß compared to the positive control. However, orientin downregulated NLRP3 and caspase-1. Lastly, primed and activated cells impaired ATP production, which was prevented by pre-treatment with açaí, Li, and orientin. In conclusion, we suggest that açaí could be a potential agent to treat or prevent neuropsychiatric diseases related to neuroinflammation.