Environmental Temperature Variation Affects Brain Lipid Composition in Adult Zebrafish (Danio rerio).

This study delves deeper into the impact of environmental temperature variations on the nervous system in teleost fish. Previous research has demonstrated that exposing adult zebrafish (Danio rerio) to 18 °C and 34 °C for 4 or 21 days induces behavioural changes compared to fish kept at a control temperature of 26 °C, suggesting alterations in the nervous system. Subsequent studies revealed that these temperature conditions also modify brain protein expression, indicating potential neurotoxic effects. The primary aim of this work was to investigate the effects of prolonged exposure (21 days) to 18 °C or 34 °C on the brain lipidomes of adult zebrafish compared to a control temperature. Analysis of the brain lipidome highlighted significant alteration in the relative abundances of specific lipid molecules at 18 °C and 34 °C, confirming distinct effects induced by both tested temperatures. Exposure to 18 °C resulted in an increase in levels of phospholipids, such as phosphatidylethanolamine, alongside a general reduction in levels of sphingolipids, including sphingomyelin. Conversely, exposure to 34 °C produced more pronounced effects, with increases in levels of phosphatidylethanolamine and those of various sphingolipids such as ceramide, gangliosides, and sphingomyelin, alongside a reduction in levels of ether phospholipids, including lysophosphatidylethanolamine ether, phosphatidylethanolamine ether, and phosphatidylglycerol ether, as well as levels of glycolipids like monogalactosyldiacylglycerol. These results, when integrated with existing proteomic and behavioural data, offer new insights into the effects of thermal variations on the nervous system in teleost fish. Specifically, our proteomic and lipidomic findings suggest that elevated temperatures may disrupt mitochondrial function, increase neuronal susceptibility to oxidative stress and cytotoxicity, alter axonal myelination, impair nerve impulse transmission, hinder synapse function and neurotransmitter release, and potentially lead to increased neuronal death. These findings are particularly relevant in the fields of cell biology, neurobiology, and ecotoxicology, especially in the context of global warming.

Living under natural conditions of ocean acidification entails energy expenditure and oxidative stress in a mussel species.

We investigated the health conditions of the Mediterranean mussel Mytilus galloprovincialis recruited in the CO2 vents system of Castello Aragonese at Ischia Island (Mediterranean Sea). Individuals of M. galloprovincialis were sampled in three sites along the pH gradient (8.10, 7.7 and up to <7.4). Untargeted metabolomics and biochemical endpoints related to energetic metabolism, oxidative stress/damage, neurotoxicity and immune defense were analyzed. Corrosion of the valves occurred at low pH. A separation of the metabolome was observed along the pH gradient. Metabolites belonging to amino acids, nucleosides, lipids and organic osmolytes were significantly reduced in the organisms from the most acidified sites. The content of reactive oxygen species and the activity of glutathione peroxidase were reduced in organisms from the acidified sites compared to ambient pH, and no oxidative damage was induced. Overall results suggested the presence of an energy cost underpinning long-term survival in acidified conditions for this species.

Multi-omics profiling of CSF from spinal muscular atrophy type 3 patients after nusinersen treatment: a 2-year follow-up multicenter retrospective study.

Spinal muscular atrophy (SMA) is a neurodegenerative disorder caused by mutations in the SMN1 gene resulting in reduced levels of the SMN protein. Nusinersen, the first antisense oligonucleotide (ASO) approved for SMA treatment, binds to the SMN2 gene, paralogue to SMN1, and mediates the translation of a functional SMN protein. Here, we used longitudinal high-resolution mass spectrometry (MS) to assess both global proteome and metabolome in cerebrospinal fluid (CSF) from ten SMA type 3 patients, with the aim of identifying novel readouts of pharmacodynamic/response to treatment and predictive markers of treatment response. Patients had a median age of 33.5 [29.5; 38.25] years, and 80% of them were ambulant at time of the enrolment, with a median HFMSE score of 37.5 [25.75; 50.75]. Untargeted CSF proteome and metabolome were measured using high-resolution MS (nLC-HRMS) on CSF samples obtained before treatment (T0) and after 2 years of follow-up (T22). A total of 26 proteins were found to be differentially expressed between T0 and T22 upon VSN normalization and LIMMA differential analysis, accounting for paired replica. Notably, key markers of the insulin-growth factor signaling pathway were upregulated after treatment together with selective modulation of key transcription regulators. Using CombiROC multimarker signature analysis, we suggest that detecting a reduction of SEMA6A and an increase of COL1A2 and GRIA4 might reflect therapeutic efficacy of nusinersen. Longitudinal metabolome profiling, analyzed with paired t-Test, showed a significant shift for some aminoacid utilization induced by treatment, whereas other metabolites were largely unchanged. Together, these data suggest perturbation upon nusinersen treatment still sustained after 22 months of follow-up and confirm the utility of CSF multi-omic profiling as pharmacodynamic biomarker for SMA type 3. Nonetheless, validation studies are needed to confirm this evidence in a larger sample size and to further dissect combined markers of response to treatment.

Alginate coating modifies the biological effects of cerium oxide nanoparticles to the freshwater bivalve Dreissena polymorpha.

The adsorption of biomacromolecules is a fundamental process that can alter the behaviour and adverse effects of nanoparticles (NPs) in natural systems. While the interaction of NPs with natural molecules present in the environment has been described, their biological impacts are largely unknown. Therefore, this study aims to provide a first evidence of the influence of biomolecules sorption on the toxicity of cerium oxide nanoparticles (CeO2NPs) towards the freshwater bivalve Dreissena polymorpha. To this aim, we compared naked CeO2NPs and coated with alginate and chitosan, two polysaccharides abundant in aquatic environments. Mussels were exposed to the three CeO2NPs (naked, chitosan- and alginate-coated) up to 14 days at 100 µg L-1, which is a concentration higher than the environmental one predicted for this type of NP. A suite of biomarkers related to oxidative stress and energy metabolism was applied, and metabolomics was also carried out to identify metabolic pathways potentially targeted by CeO2NPs. Results showed that the coating with chitosan reduced NP aggregation and increased the stability in water. Nonetheless, the Ce accumulation in mussels was similar in all treatments. As for biological effects, all three types of CeO2NPs reduced significantly the level of reactive oxygen species and the activity of superoxide dismutase, glutathione peroxidase and glutathione-S-transferase. The effect was more pronounced in individuals exposed to CeO2NPs coated with alginate, which also significantly induced the activity of the electron transport system. Metabolomics analysis of amino acid metabolism showed modulation only in mussels treated with CeO2NPs coated with alginate. In this group, 25 metabolites belonging to nucleotides, lipids/sterols and organic osmolytes were also modulated, suggesting that the nanoparticles affect energetic metabolism and osmoregulation of mussels. This study highlights the key role of the interaction between nanoparticles and natural molecules as a driver of nanoparticle ecotoxicity.

FragClust and TestClust, two informatics tools for chemical structure hierarchical clustering analysis applied to lipidomics. The example of Alzheimer's disease.

Lipidomic analysis is able to measure simultaneously thousands of compounds belonging to a few lipid classes. In each lipid class, compounds differ only by the acyl radical, ranging between C10:0 (capric acid) and C24:0 (lignoceric acid). Although some metabolites have a peculiar pathological role, more often compounds belonging to a single lipid class exert the same biological effect. Here, we present a lipidomics workflow that extracts the tandem mass spectrometry data from individual files and uses them to group compounds into structurally homogeneous clusters by chemical structure hierarchical clustering analysis (CHCA). The case-to-control peak area ratios of the metabolites are then analyzed within clusters. We created two freely available applications to assist the workflow: FragClust to generate the tables to be subjected to CHCA, and TestClust to perform statistical analysis on clustered data. We used the lipidomics data from the plasma of Alzheimer's disease (AD) patients in comparison with healthy controls to test the workflow. To date, the search for plasma biomarkers in AD has not provided reliable results. This article shows that the workflow is helpful to understand the behavior of whole lipid classes in plasma of AD patients.