Biology subjects

Dantas, L. S.

Publications and source records attributed to Dantas, L. S..

3 recordsLinked to original sources

bioRxiv2025

Oxysterol Alterations in SOD1G93A ALS Rats: 25-Hydroxycholesterol and LPS-Binding Protein in Disease Progression

BackgroundDisruptions in cholesterol and oxysterol metabolism, along with neuroinflammation, are linked to amyotrophic lateral sclerosis (ALS), though the underlying mechanisms remain unclear. Given evidence of increased intestinal permeability in ALS, we investigated its link to neuroinflammation and oxysterol alterations in SOD1G93A rats. MethodsOxysterols were quantified in plasma and spinal cord from presymptomatic and symptomatic SOD1G93A rats and age-matched controls via ultra-high performance liquid chromatography coupled with high-resolution mass spectrometry. Circulating LBP, a marker of intestinal permeability, was quantified via ELISA. ResultsOxysterols involved in bile acid biosynthesis - 7-hydroxycholesterol, 27-hydroxycholesterol (27-OH), and 3{beta}-hydroxycholestenoic acid - were increased in the plasma of symptomatic rats. The neuronal oxysterol 24(S)-hydroxycholesterol (24(S)-OH) decreased in the spinal cord but increased in the plasma. In contrast, 27-OH and 25-hydroxycholesterol (25-OH) levels were elevated in both plasma and spinal cord, with 25-OH rising during the presymptomatic stage. Presymptomatic animals also exhibited elevated LBP levels, which strongly correlated with spinal cord 25-OH levels, suggesting a link between systemic inflammation and neuroinflammation in ALS. ConclusionOxysterol alterations in plasma and spinal cord suggest compromised blood-spinal cord barrier integrity and early neuroinflammation. Elevated LBP levels indicate increased intestinal permeability and circulating LPS as contributors to neuroinflammation and neurodegeneration. These findings highlight 25-OH and LBP as markers and mediators of gut-brain axis interactions in ALS pathogenesis, particularly in the presymptomatic phase.

neuroscience↗

bioRxiv2023

Plasma Oxylipin Profiling by High Resolution Mass Spectrometry Reveal Signatures of Inflammation and Hypermetabolism in Amyotrophic Lateral Sclerosis

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease characterized not only by progressive loss of motor neurons, but also linked to systemic hypermetabolism, oxidative stress, and inflammation. In this context, oxylipins have been investigated as signaling molecules linked to neurodegeneration. However, the nature and role of major oxylipins involved in ALS disease progression remain unclear. Importantly, most methods focused on oxylipin analysis are based on low resolution mass spectrometry (LRMS), which usually confers high sensitivity, but not great accuracy for lipid identification, as provided by high-resolution MS (HRMS). Here, we established an ultra-high performance liquid chromatography coupled HRMS (LC-HRMS) method for simultaneous analysis of 126 oxylipins in plasma, including lipid hydroxides, ketones, epoxides, prostaglandins, leukotrienes, and others in a 15-minute run. Intra- and inter-day method validation showed high sensitivity (0.3 - 25 pg), accuracy and precision for more than 90 % of quality controls. This method was applied for the analysis of oxylipins in plasma of ALS rats overexpressing the mutant human Cu/Zn-superoxide dismutase gene (SOD1-G93A) at asymptomatic (ALS 70 days old) and symptomatic stages (ALS 120 days old), and their respective age-matched wild type controls (WT 70 days old and WT 120 days old). From the 56 oxylipins identified in plasma, 17 species were significantly altered. Remarkably, most of oxylipins linked to inflammation and oxidative stress derived from arachidonic acid, such as, prostaglandins, lipoxins, mono-hydroxides, and isoprostane, were increased in ALS 120d rats. In contrast, the linoleic acid diols involved in fatty acid uptake and {beta}-oxidation, 9(10)-DiHOME and 12(13)-DiHOME, were strongly decreased in the ALS 120d. In summary, we developed and validated a high-throughput LC-HRMS method for oxylipin analysis and provided a comprehensive overview of plasma oxylipins involved in ALS disease progression. Noteworthy, the oxylipins altered in plasma of ALS 120d rats have potential to be investigated and used as biomarkers for inflammation and hypermetabolism in ALS. GRAPHICAL ABSTRACT O_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=136 SRC="FIGDIR/small/547101v1_ufig1.gif" ALT="Figure 1"> View larger version (40K): org.highwire.dtl.DTLVardef@937099org.highwire.dtl.DTLVardef@1c5847forg.highwire.dtl.DTLVardef@7dd09borg.highwire.dtl.DTLVardef@a9f8d_HPS_FORMAT_FIGEXP M_FIG C_FIG

biochemistry↗

bioRxiv2019

Lipid-derived electrophiles induce covalent modification and aggregation of Cu,Zn-superoxide dismutase in a hydrophobicity-dependent manner

Lipid peroxidation generates a huge number of reactive electrophilic aldehyde products. These reactive aldehydes can modify macromolecules such as proteins, resulting in loss of function and/or aggregation. The accumulation of Cu,Zn-superoxide dismutase (SOD1) aggregates is associated with familial cases of amyotrophic lateral sclerosis (ALS). Recent studies have shown that lipid and its oxidized derivatives may play a role in this process. Here we aimed to compare and characterize the ability of lipid-derived electrophiles with different hydrophobicities to induce SOD1 modification and aggregation in vitro. SOD1 was incubated with 4-hydroxy-2-hexenal (HHE), 4-hydroxy- 2-nonenal (HNE), 2-hexen-1-al (HEX), 2,4-nonadienal (NON), 2,4-decadienal (DEC) or secosterol aldehydes (Seco-A or Seco-B) at 37{degrees}C for 24 h. Size exclusion chromatography analysis showed that hydrophobic aldehydes smarkedly enhances apo- SOD1 aggregation. More importantly, aggregation level was positively correlated to calculated aldehyde hydrophobicities (LogP). Protein sequencing by LC-MS/MS showed that aldehydes covalently modifies SOD1 at aggregation prone regions. For instance, specific lysine residues located mainly nearby the dimer interface (K3, K9) and at the electrostatic loop (K122, K128, K136) were ubiquitously modified by all aldehydes. The ,{beta}-unsaturated aldehydes also promoted modifications on histidine and cysteine residues, with H120 and C6 being the most commonly modified residues. Overall, our data suggest that electrophiles hydrophobicity is a critical factor that strongly influences protein aggregation propensity.\n\nGraphical abstract\n\nO_FIG O_LINKSMALLFIG WIDTH=200 HEIGHT=116 SRC=\"FIGDIR/small/740688v1_ufig1.gif\" ALT=\"Figure 1\">\nView larger version (26K):\norg.highwire.dtl.DTLVardef@1860bc3org.highwire.dtl.DTLVardef@16e4cb6org.highwire.dtl.DTLVardef@6e48a4org.highwire.dtl.DTLVardef@631070_HPS_FORMAT_FIGEXP M_FIG C_FIG Highlights- Aldehyde hydrophobicity is positively correlated to SOD1 aggregation;\n\n- Lys residues located nearby the SOD1 dimer interface and electrostatic loop are ubiquitously modified by all aldehydes;\n\n- Hydrophobic aldehydes increase the lipophilic potential surface of the region where they bind;

biochemistry↗