Amparo Alfonso

Ischemia induces oxidative stress and mitochondrial dysfunction in microglia, contributing to neuro-inflammation and neuronal damage. Five furanoditerpenes 1–5, isolated from the marine sponge Spongia (Spongia) tubulifera, have previously shown neuroprotective effects related to their capacity to bind cyclophilin D (CypD), a protein involved in ischemia. In this study, the ability of compounds 1–5 to alleviate ischemic damage was evaluated on BV2 microglial cells. First, cells were incubated under oxygen deprivation for 6 h, and the five compounds were able to improve cell viability at micromolar concentrations (0.001–1 μM). Then, hypoxia was combined with the inflammatory stimulus lipopolysaccharide and with glucose deprivation, and Spongia tubulifera metabolites maintained their protective effects. When oxygen and glucose deprivation was followed by 6 h of reperfusion, compounds 1–5 also mitigated the damage produced on microglia. Moreover, these furanoditerpenes reduced reactive oxygen species overproduction and restored mitochondrial membrane potential, key factors in ischemic damage. This effect was mediated by the regulation of CypD since compounds 2, 4, and 5 reduced its expression under ischemia conditions. Finally, trans-well coculture experiments were performed between microglial and SH-SY5Y neuronal cells. In this assay, compounds 2, 4, and 5 protected neuronal cells from microglial-induced neurotoxicity under ischemia/reperfusion conditions. These findings suggest that S. tubulifera metabolites display mitochondrial-mediated antioxidant and cytoprotective effects under ischemic conditions through CypD modulation. Given the limitations of current Cyps inhibitors like cyclosporin A, compounds 1–5 are promising therapeutic candidates for ischemia-related diseases, such as stroke.

Hyperglycemia is associated with pro-inflammatory reprogramming of macrophages, increase of reactive oxygen species (ROS) levels and variations in ATP cons

Sponges of the genus Neopetrosia are known for the production of a large diversity of bioactive metabolites. Contignasterines A (1) and B (2) were isolated as major metabolites of the sponge Neopetrosia cf. rava collected in the Bismarck Sea along with the known and highly bioactive steroid contignasterol (3) possessing a similar oxidized aglycone. Contignasterines are characterized by the presence of a 2-aminoimidazole branched on the side-chains of the oxidized steroid, and 1 also contains an unusual phosphate group at C-7. The anti-inflammatory activities of these compounds were investigated and revealed that all three compounds inhibited the production of pro-inflammatory mediators.

Some Penicillium strains used in cheese ripening produce emerging mycotoxins, notably roquefortine C (ROQC) and cyclopiazonic acid (CPA), as well as enniatins (ENNs) and beauvericin (BEA). Co-occurrence of these mycotoxins in natural samples has been reported worldwide, however, most studies focus on the toxicity of a single mycotoxin. In the present study, the effects of ROQC and CPA alone and in combination with BEA and ENNs A, A1, B, and B1 were analysed in human neuroblastoma cells. ROQC and CPA reduced cell viability, with IC₅₀ values of 49.5 and 7.3 µM, respectively, and induced caspase-8-mediated apoptosis. When ROQC and CPA were binary combined with ENNs, an enhancement of their individual effects was observed. Furthermore, a clear synergism was produced when ROQC and CPA were mixed with the four ENNs. An additive effect was also described for the combination of CPA + ENNs (A, A1, B, B1) + BEA. Finally, the effects of commercial cheese extracts containing the mentioned mycotoxins were evaluated, finding a strong reduction in cell viability. These results suggest that the co-occurrence of emerging mycotoxins in natural matrices could pose a potential health risk.

Yogurt, a milk-derived product, is susceptible to mycotoxin contamination. While various methods have been developed for the analysis of dairy products, only a few have been specifically validated for yogurt. In addition, these methods are primarily focus on detecting aflatoxins and zearalenone. This study aimed to conduct a preliminary investigation into the presence of regulated, emerging, and modified mycotoxins in natural and oat yogurts available in the Spanish market. For this, a QuEChERS-based extraction method was optimized and then validated to detect and quantify 32 mycotoxins using ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The method was in-house validated for the analysis of natural and oat yogurt in terms of linearity, matrix effect, sensitivity, accuracy, and precision. Satisfactory performance characteristics were achieved; for most of the analytes, LOQs were lower than 2 ng/g, and recoveries ranged from 60 to 110% with a precision, expressed as the relative standard deviation of the recovery, lower than 15%. Subsequently, the validated method was applied to analyze commercial yogurt samples, revealing a notable incidence of beauvericin and enniatins, with some analogues found in up to 100% of the samples. Alternariol methyl ether was also frequently found, appearing in 50% of the samples. Additionally, the study identified regulated toxins such as fumonisins, ochratoxin A , and HT-2 toxin. These results provide new incidence data in yogurt, raising concerns about potential health risks for consumers.

Enniatins (ENNs) A1 and B1, previously considered ionophores, are emerging mycotoxins with effects on Ca²⁺ homeostasis. However, their exact mechanism of action remains unclear. This study investigated how these toxins affect Ca²⁺ flux in SH-SY5Y cells. ENN A1 induced Ca²⁺ influx through store-operated channels (SOC). The mitochondrial uncoupler FCCP reduced this influx, suggesting that the mitochondrial status influences the toxin effect. Conversely, ENN B1 did not affect SOC but acted on another Ca²⁺ channel, as shown when nickel, which directly blocks the Ca²⁺ channel pore, is added. Mitochondrial function also influenced the effects of ENN B1, as treatment with FCCP reduced toxin-induced Ca²⁺ depletion and uptake. In addition, both ENNs altered mitochondrial function by producing the opening of the mitochondrial permeability transition pore. This study describes for the first time that ENN A1 and B1 are not Ca²⁺ ionophores and suggests a different mechanism of action for each toxin.

Psammaplins are sulfur containing bromotyrosine alkaloids that have shown antitumor activity through the inhibition of class I histone deacetylases (HDACs). The cytotoxic properties of psammaplin A (1), the parent compound, are related to peroxisome proliferator-activated receptor γ (PPARγ) activation, but the mechanism of action of its analogs psammaplin K (2) and bisaprasin (3) has not been elucidated. In this study, the protective effects against oxidative stress of compounds 1-3, isolated from the sponge Aplysinella rhax, were evaluated in SH-SY5Y cells. The compounds improved cell survival, recovered glutathione (GSH) content, and reduced reactive oxygen species (ROS) release at nanomolar concentrations. Psammaplins restored mitochondrial membrane potential by blocking mitochondrial permeability transition pore opening and reducing cyclophilin D expression. This effect was mediated by the capacity of 1-3 to activate PPARγ, enhancing gene expression of the antioxidant enzymes catalase, nuclear factor E2-related factor 2 (Nrf2), and glutathione peroxidase. Finally, HDAC3 activity was reduced by 1-3 under oxidative stress conditions. This work is the first description of the neuroprotective activity of 1 at low concentrations and the mechanism of action of 2 and 3. Moreover, it links for the first time the previously described effects of 1 in HDAC3 and PPARγ signaling, opening a new research field for the therapeutic potential of this compound family.