Integrated Hepatic Lipidome Analysis in Aging Mice

Untargeted serum lipidomics reveals lipid metabolic disturbances and identifies candidate lipid biomarkers in acute diquat poisoning.

Diquat (DQ) has emerged as an important cause of herbicide poisoning following restrictions on paraquat (PQ) and is associated with multi-organ injury involving the liver, kidneys, and brain. Acute DQ poisoning is characterized by marked lipid metabolic dysregulation, including elevated free fatty acids (FFA) and reduced triglycerides (TG). Nevertheless, the mechanisms responsible for these lipid abnormalities remain unclear. To further characterize the lipidomic landscape of acute DQ poisoning, we performed untargeted serum lipidomics using ultra-high-performance liquid chromatography in combination with high-resolution mass spectrometry in 52 confirmed bipyridyl poisoning cases (32 DQ and 20 PQ). KEGG pathway enrichment analysis revealed significant perturbations in glycerophospholipid, glycerolipid, linoleic acid, α-linolenic acid, and arachidonic acid metabolism following DQ exposure. Within 6 h after ingestion, several O-acylhydroxy fatty acids and fatty acids (20:4) tended to increase, and these lipid alterations appeared earlier than laboratory parameters. Triglyceride (26:0/18:2/18:2) and sphingomyelin (d42:8) were independently associated with 28-day mortality. Compared with DQ poisoning, PQ poisoning exhibited a more pronounced depletion of plasmalogen-phosphatidylethanolamines despite broadly similar overall lipidomic profiles. The observed lipidomic alterations suggest that acute DQ poisoning may promote excessive lipolysis, disrupt glycerophospholipid homeostasis, and impair mitochondria-associated membrane function, thereby potentially contributing to oxidative stress and organ dysfunction. These findings demonstrate substantial lipid metabolic disturbances following acute DQ poisoning and identify candidate lipid markers that warrant further evaluation for diagnosis and prognosis.

Persistent lipotoxicity overwhelms adaptive capacity in human hepatic cell line.

BACKGROUND Chronic fatty acid (FA) elevation drives metabolic dysfunction-associated liver disease (MASLD). Hepatocytes buffer transient lipid overload via coordinated adaptive mechanisms, but the temporal limits of this capacity remain undefined. OBJECTIVES We characterized early, intermediate, and prolonged hepatocellular responses to sustained lipid excess. METHODS HuH7 hepatocytes were exposed to an equimolar palmitic/oleic acid (PA/OA) mixture for 1, 14, or 28 days. Viability, lipid accumulation, stress-response pathways, insulin signaling, metabolic regulators, mitochondrial markers, [14C]-PA uptake, and exo-metabolomic profiles were assessed (n≥3/group). Data (mean ± SEM) were analyzed by two-way ANOVA with Bonferroni post hoc testing; cumulative cell death by linear regression. P<0.05 was significant. RESULTS FA treatment increased lipid droplet accumulation 1.4- to 1.7-fold vs. time-matched BSA controls at all time points (p<0.001) and increased the rate of cumulative cell death ∼4.3-fold (1.556±0.083 vs. 0.365±0.054%/day, p<0.001). Exo-metabolomic PCA explained 88.5% of variance (Q2=0.758), with peak lactate release at Day 14 and progressively rising acetate through Day 28. [14C]-PA accumulation at Day 28 was ∼30% lower than Day 1 (∼800 vs. ∼500 cpm/mg protein), with a declining rather than plateauing profile between 20-60 s. By Day 28, FA-treated cells showed lower FASN (p<0.001), CD36 (p<0.05), FABP1 (p<0.001), SIRT1 (p<0.005), and CLOCK (p<0.01) protein levels, and higher CPT1A (p<0.001), pAMPK/AMPK (p<0.01), p53 (p<0.001), Bax/Bcl2 (p<0.005), and respiratory complex I-V abundance (p<0.05-p<0.001) vs. controls. CONCLUSIONS Sustained PA/OA exposure induces a staged hepatocellular response, early lipid-buffering adaptation, intermediate metabolic compensation, and late decompensation, indicating that chronic lipotoxicity reflects progressive loss of regulatory coordination despite persistent metabolic adaptation.

Metabolomics and Lipidomics Study Reveals Metabolic Dysregulation in Epididymal Adipose Tissue of db / db Mice

Plasma as Proxy for Tissue Metabolism When Extending Lifespan in Mice

Objective: Despite most often used in research and medicine, it is unclear how well blood metabolite levels can reflect metabolic changes in tissues. Methods: We used untargeted metabolomic data from plasma, liver, gastrocnemius muscle, kidney, inguinal fat, and gonadal fat tissues from mice treated with lifespan-extending interventions: caloric restriction, rapamycin, canagliflozin, 17-α estradiol, and acarbose. Results: For each tissue, about 37% of the identified metabolites were also found in plasma and used for comparative analyses. We found that plasma metabolites do not primarily reflect the metabolome of a single tissue type. Caloric restriction caused the highest proportion of significantly altered metabolites detected in both organs and blood. Unsaturated triacylglycerols, diacylglycerols, amino acid-derivatives, and sphingomyelins had the most concordant overlaps between four tissues and plasma, followed by carbohydrates with three tissue/plasma intersections. Concordant plasma/tissue changes were found more pronounced in male mice than in female mice. Surprisingly, many compounds that responded similarly to lifespan-extending treatments in tissues and in plasma originated from dietary compounds, specifically, ergothioneine, DHA-containing fats, and diacylglycerides. Ergothioneine, previously associated with healthy aging in humans, showed concordant treatment responses in blood and all tissues except gonadal fat. DHA-containing fats showed consistent regulation between blood and inguinal and gonadal adipose tissue. The kidneys showed coherent trends with blood metabolite levels for LPC 15:0, LPC 17:0, and pinitol. Under treatments with strong life-extending effects, 1,5-anhydro-glucitol blood levels were co-regulated with both liver and kidney levels. Conclusions: Overall, plasma can only serve as limited proxy for tissue metabolism. Yet, several potential blood biomarkers were discovered as concordant in plasma and tissues in lifespan-extending interventions.

Spatially resolved hepatic lipid metabolism perturbation and gut microbiota dysbiosis induced by a novel PFOA alternative in zebrafish (Danio rerio).

The distribution of environmental pollutants and their associated metabolic perturbations within tissues is essential for understanding toxicological mechanisms. However, whether hexafluoropropylene oxide tetramer acid (HFPO-TeA), an emerging alternative to legacy PFASs, induces spatially heterogeneous metabolic disruption in aquatic organisms remains unclear. Here, adult zebrafish were exposed to HFPO-TeA to investigate hepatic phospholipid spatial distribution and gut microbial dysfunction. Matrix-assisted laser desorption/ionization quadrupole time-of-flight mass spectrometry imaging (MALDI-QTOF-MSI) revealed marked spatial perturbation of 14 putatively annotated lipid features, mainly including phosphatidylcholines (PCs), phosphatidylglycerols (PGs), phosphatidylethanolamines (PEs), diacylglycerols (DAGs), and phosphatidylinositols (PIs). Notably, these phospholipids exhibited region-specific down- or up-regulation, suggesting localized phospholipid remodeling within hepatic microdomains rather than spatially uniform disruption. These spatially resolved phospholipid alterations provide mechanistically relevant evidence for HFPO-TeA-induced hepatotoxicity and phospholipids with annotated spatial perturbation as candidate lipid-feature biomarkers for future validation. Moreover, HFPO-TeA reduced gut microbial diversity and reshaped the intestinal community, including decreases in Firmicutes at the phylum level and increases in Shewanella and Aeromonas at the genus level, taxa linked to lipid metabolism and phospholipid remodeling. Functional prediction further indicated suppressed microbial metabolic potential, with relative enrichment of genetic information processing and cellular maintenance functions. Together, the microbiome shift toward phospholipid remodeling-associated taxa and the spatially resolved hepatic perturbation of specific phospholipids provide convergent evidence that targeted phospholipid metabolic remodeling within tissue microregions may underlie HFPO-TeA-induced metabolic toxicity. This study provides a spatially resolved perspective on the multilevel metabolic toxicity of HFPO-TeA and demonstrates significant potential for revealing the health impacts of emerging PFAS alternatives.

Lipidomics Based on HILIC-ESI-HRMS Reveal Subtle Changes in the Mitochondrial Phospholipidome of Mouse Embryonic Fibroblasts Expressing Pathogenic Variants of Human OPA1 Protein

Pathogenic variants of the mammalian optic atrophy 1 (OPA1) protein, a key regulator of mitochondrial fusion, may lead to severe mitochondrial dysfunction and morphological alterations, and have also been proposed to be involved in remodeling the mitochondrial membranes lipid profile. To address this last issue, a lipidomic workflow based on HILIC-ESI-HRMS was applied to profile major classes of mitochondrial membrane phospholipids (PL), namely phosphatidylcholines (PCs), -ethanolamines (PEs), and -inositols (PIs), along with cardiolipins (CLs), in mouse embryonic fibroblasts knocked out for Opa1 gene (Opa1−/− MEFs) and expressing human OPA1 isoform 1 (ISO1) or one of four well-known pathogenic variants (I382M, D603H, G439V and R445H). A total of 122 common sum compositions were recognized for PLs in the four classes across the five sample types. Chemometrics on the respective quantitative data indicated a lower prevalence of alk(en)yl/acyl species (O-PCs and O-PEs) within the PC and PE classes, along with a higher relative contribution of highly unsaturated PI and CL species, when severely pathogenic R445H and G439V variants were expressed. In contrast, the I382M variant was associated with a greater relative contribution of less-unsaturated PI and CL species. These findings indicate that pathogenic OPA1 variants are associated with distinct mitochondrial phospholipid profiles, opening interesting perspectives for future direct experimental validation of an eventual relationship existing between OPA1 variants, inter-organelle phospholipid trafficking, and mitochondrial dysfunction.