Biology subjects

Faria, R. L.

Publications and source records attributed to Faria, R. L..

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↗

bioRxiv2024

Plasmalogen oxidation induces the generation of excited molecules and electrophilic lipid species

Plasmalogens are glycerophospholipids with a vinyl-ether linkage at the sn-1 position of the glycerol backbone. Despite being suggested as antioxidants due to the high reactivity of their vinyl ether groups with reactive oxygen species (ROS), our study reveals the generation reactive oxygen and electrophilic lipid species from oxidized plasmalogen intermediates. By conducting a comprehensive analysis of the oxidation products by liquid chromatography coupled to high-resolution mass spectrometry (LC-MS) we demonstrate that singlet molecular oxygen [O2 (1{Delta}g)] reacts with the vinyl ether bond, producing hydroperoxyl acetal as major primary product (97%) together with minor quantities of dioxetane (3%). Furthermore, we show that these primary oxidized intermediates lead to the formation of excited triplet carbonyls, O2 (1{Delta}g), and electrophilic phospholipid and fatty aldehyde species, as secondary reactive products. The generation of excited triplet carbonyls from dioxetane thermal decomposition was confirmed by light emission measurements in the visible region using dibromoantracene as a triplet enhancer. Moreover, O2 (1{Delta}g) generation from dioxetane and hydroperoxyacetal was evidenced by detection of near-infrared light emission at 1270 nm and chemical trapping experiments. Additionally, we have thoroughly characterized alpha-beta unsaturated phopspholipid and fatty aldehydes by LC-MS analysis using two probes that specifically reacts with aldehydes and alpha-beta unsaturated carbonyls. Overall, our findings demonstrate the generation of excited molecules and electrophilic lipid species from oxidized plasmalogen species unveiling the potential prooxidant nature of plasmalogen oxidized products. Significance StatementPlasmalogens, the most abundant subclass of ether lipids in mammalian cells, have traditionally been regarded as antioxidants. However, our study reveals a new perspective, shedding light on the generation of chemiexcited and reactive lipid species during plasmalogen photooxidation. We provide direct evidence revealing the production of excited triplet carbonyls and singlet molecular oxygen as secondary reactive products originating from dioxetane and hydroperoxyacetal intermediates. Importantly, we also demonstrate the generation of electrophilic alpha-beta unsaturated phospholipids and fatty aldehydes through plasmalogen oxidation. These findings highlight the production of excited states and reactive lipid species resulting from plasmalogen oxidation, which can potentially induce oxidative modifications in biological systems.

biochemistry↗

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↗