Capsaicin suppresses LPS-induced inflammatory responses via NLRP3/CASP-1/IL-1β axis and purinergic pathways in BV-2 microglial cells Bianca Vedoin Copês Rambo, Milagros Fanny Vera Castro, Mairin Schott, Robson Lourenço da Silva Santos, Charles Elias Assmann, et al. Purinergic Signalling, 2026 Microglial activation drives neuroinflammation, a key factor in many neurological diseases. The purinergic system is a major regulator of inflammatory responses and represents a promising target for controlling neuroinflammation. Capsaicin, a bioactive compound found in chili peppers, exhibits significant anti-inflammatory and antioxidant properties. This study aimed to investigate the modulatory effects of capsaicin on microglial activation and purinergic system regulation. For this, BV-2 microglial cells were exposed to lipopolysaccharide (1 μg/mL) and treated with capsaicin (25 and 50 μM) for 24 hours. Cell viability was assessed by MTT and trypan blue assays. Cell cycle and apoptosis were evaluated by flow cytometry. Nitric oxide, reactive species and malondialdehyde levels were evaluated as markers of oxidative stress. Activities of NTPDase, 5'-nucleotidase (5’-NT), and adenosine deaminase (ADA) were evaluated. Gene expression of inflammatory mediators and purinergic receptors were analyzed by qRT-PCR, and molecular docking analyses were performed. As a result, capsaicin decreased the expression of pro-inflammatory mediators (NLRP3, CASP-1, IL-1β, IL-6, and TNF-α), increased IL-10 expression, and attenuated oxidative stress. It reduced NTPDase, 5'-NT, and ADA activities, downregulated P2X7 and A2A receptor expression, and upregulated A1 receptor expression. Molecular docking revealed that capsaicin has a high affinity for the A1 and A2A receptors, as well as for ADA. Collectively, these findings suggest that capsaicin exerts neuroprotective effect by suppressing pro-inflammatory signaling, enhancing anti-inflammatory responses, reducing oxidative stress, and modulating key components of the purinergic system, including ectoenzyme activities and P2X7, A1, and A2A receptor expression. Graphical Abstract Lipopolysaccharide (LPS) activates microglia via the NLRP3 pathway, increasing pro-inflammatory cytokines, purinergic receptors expression (P2X7 and A2A), and the activity of CD39, CD73, and ADA. Capsaicin mitigates this inflammatory profile by inhibiting NLRP3 signaling, reducing pro-inflammatory cytokine expression and modulating purinergic signaling toward an anti-inflammatory profile. Illustrations were obtained from Servier Medical Art ( https://smart.servier.com/ ), licensed under the Creative Commons Attribution 4.0 International License (CC BY 4.0).
Quercetin and Tranylcypromine Improve Memory, Behavioral Performance, and Cholinergic Function in Male Rats Subjected to Chronic Restraint Stress Vitor Bastianello Mostardeiro, Charles Elias Assmann, Adriel Antonio Schirmann, Marcylene Vieira da Silveira, Bianca Vedoin Copês Rambo, et al. Brain Sciences, 2025 Background/Objectives: Major depressive disorder (MDD) is a debilitating illness, and chronic stress is a contributing factor for depressive symptoms. However, despite intense research, the mechanisms of MDD remain substantially unidentified. Quercetin is a powerful flavonoid and could be used as a possible therapeutic strategy for depression. Acknowledging the potential benefits of quercetin, this study investigated its effect alone or in association with the standard drug tranylcypromine (TCP) in a rodent model of chronic restraint stress (CRS). Methods: Adult male rats were subjected to a CRS model consisting of an immobilization session of 4 h daily during 14 consecutive days. Quercetin (50 mg/kg, gavage) was administered for 45 days. TCP (10 mg/kg, gavage) was administered for 14 days. Behavioral tasks were conducted to assess locomotor functions, memory, anhedonia, depression-like behaviors, and anxiety-like behaviors. The activity, gene expression, and protein density of acetylcholinesterase (AChE) were investigated. Results: Behavioral tasks showed that the CRS model effectively induced stable behavioral changes. CRS did not alter locomotor function assessed by the open field test (OFT) or anhedonia behavior assessed by the sucrose preference test (SPT). CRS increased total fecal count, which was prevented by quercetin administration in rats. TCP and the association of quercetin and TCP increased the recognition index in comparison with the CRS group in the novel object recognition (NOR) test and improved the swimming and immobility times in comparison to stressed animals in the forced swim test (FST). All treatments were able to decrease the anxiety index assessed by the elevated plus maze (EPM) test. The activity, gene expression, and protein density of AChE were increased in the CRS model compared to control males. Overall, quercetin and TCP proved to reverse CRS-induced alterations in these parameters. Conclusions: Quercetin mitigated cognitive deficits, behavioral impairments, and neurochemical alterations induced by the CRS model, especially in association with TCP, supporting its potential as a promising therapeutic agent for depression.
Effects of Free and Nanoencapsulated Benznidazole in Acute Trypanosoma cruzi Infection: Role of Cholinergic Pathway and Redox Status Aniélen D. da Silva, Mateus Fracasso, Nathieli B. Bottari, Taís V. Palma, Ana M. Engelmann, et al. Pharmaceuticals, 2024 Background/Objectives: The Trypanosoma cruzi infection promotes an intense inflammatory process that affects several tissues. The cholinergic system may exert a regulatory immune response and control the inflammatory process. This study aimed to evaluate the comparative effect of free and nanoencapsulated benznidazole in acute T. cruzi infection to assess hematological, biochemical, and oxidative status triggered by the cholinergic system. Methods: For this, fifty female Swiss mice were distributed in eight groups, i.e., uninfected and infected animals under four treatment protocols: untreated (control—CT); vehicle treatment (Eudragit L 100—EL-100); benznidazole treatment (BNZ); and nanoencapsulated benznidazole treatment (NBNZ). After eight treatment days, the animals were euthanized for sample collection. Results: The peak of parasitemia was at day 7 p.i., and the BNZ and NBNZ controlled and reduced the parasite rate but showed no efficacy in terms of total elimination of parasites analyzed by RT-PCR in both infected groups. The infection promotes significant anemia, leukopenia, and thrombocytopenia, which the BNZ improves. There was an increase in AChE activity during infection, leading to a pro-inflammatory response and an increase in M1 and M2 mACh receptors in the BNZ group, showing that the treatment interacted with the cholinergic pathway. In addition, a pro-oxidative response was characterized in the infection and mainly in the infected BNZ and NBNZ groups. The histopathological analysis showed significative splenomegaly and inflammatory infiltrate in the heart, liver, and spleen. Conclusions: The administration of the BNZ or NBNZ reverses hematological, hepatic, and renal alterations through cholinergic signaling and stimulates a pro-inflammatory response during acute T. cruzi infection.
Neuroprotective effect of long-term resistance physical exercise against memory damage elicited by a lipopolysaccharide-induced neuroinflammation model in male rats Vanessa Valéria Miron, Charles Elias Assmann, Vitor Bastianello Mostardeiro, Marcylene Vieira da Silveira, Priscila Marquezan Copetti, et al. Journal of Neuroscience Research, 2024 Resistance exercise training (RET) is considered an excellent tool for preventing diseases with an inflammatory background. Its neuroprotective, antioxidant, and anti‐inflammatory properties are responsible for positively modulating cholinergic and oxidative systems, promoting neurogenesis, and improving memory. However, the mechanisms behind these actions are largely unknown. In order to investigate the pathways related to these effects of exercise, we conducted a 12‐week long‐term exercise training protocol and used lipopolysaccharide (LPS) to induce damage to the cortex and hippocampus of male Wistar rats. The cholinergic system, oxidative stress, and histochemical parameters were analyzed in the cerebral cortex and hippocampus, and memory tests were also performed. It was observed that LPS: (1) caused memory loss in the novel object recognition (NOR) test; (2) increased the activity of acetylcholinesterase (AChE) and Iba1 protein density; (3) reduced the protein density of brain‐derived neurotrophic factor (BDNF) and muscarinic acetylcholine receptor M1 (CHRM1); (4) elevated the levels of lipid peroxidation (TBARS) and reactive species (RS); and (5) caused inflammatory damage to the dentate gyrus. RET, on the other hand, was able to prevent all alterations induced by LPS, as well as increase per se the protein density of the alpha‐7 nicotinic acetylcholine receptor (nAChRα7) and Nestin, and the levels of protein thiols (T‐SH). Overall, our study elucidates some mechanisms that support resistance physical exercise as a valuable approach against LPS‐induced neuroinflammation and memory loss.
