Changes In Lipidome Research Articles

39-OR: Pancreatic Beta Cell SERCA2 Deficiency Impacts ER-Golgi Vesicle Trafficking and Ceramide Metabolism

Alterations in endoplasmic reticulum (ER) calcium (Ca2+) levels arising from reduced activity of the Sarcoendoplasmic Reticulum Ca2+ ATPase (SERCA) pump are associated with impaired insulin secretion and reduce β-cell survival in both major forms of diabetes. However, at present, the mechanisms of how reduced ER Ca2+ impairs β-cell function remain incompletely understood. To test this, we analyzed mice with β-cell specific SERCA2 deletion (βS2KO mice) and S2KO INS1 cells. βS2KO mice exhibited age-dependent glucose intolerance, reduced glucose-stimulated insulin secretion, and increased proinsulin secretion without evidence of impaired insulin sensitivity. Immunoblot analysis of βS2KO islets and S2KO INS-1 cells revealed reduced active forms of the proinsulin processing enzymes, PC1/3, PC2, and CPE, while immunofluorescence analysis suggested impaired ER-Golgi trafficking of the convertase enzymes and proinsulin. Because the ER serves as the main site of cellular lipid synthesis and changes in the β-cell lipidome have been linked with diabetes pathophysiology, we hypothesized that ER Ca2+ loss may alter protein trafficking in the secretory pathway through changes in ER lipid content. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was performed on the ER fractions of control and S2KO INS1 cells and revealed increased levels of 16:0, 24:0, 24:1, and total ceramides in S2KO cells. SERCA2 restoration partially rescued convertase enzyme expression, proinsulin processing, and ceramide content. Consistent with these findings, RNA sequencing analysis of βS2KO islets revealed changes in pathways related to vesicle transport, protein processing, and lipid metabolism. We conclude that SERCA2 in the β-cell plays a central role in the maintenance of insulin biosynthesis as well as ceramide metabolism. Disclosure T. Kono: None. H. Iida: None. C. Lee: None. P. Krishnan: None. P. Arvan: None. I. Lindberg: None. C. Evans-molina: Advisory Panel; Self; Provention Bio, Inc., Consultant; Self; Dompe, Other Relationship; Self; Bristol-Myers Squibb Company, Nimbus Pharmaceuticals, Pfizer Inc. Funding National Institutes of Health (R01DK093954)

Investigation of the lipidomic changes in differentiated glioblastoma cells after drug treatment using MALDI-MS

Lipids differences between tumor and normal tissue have been proved to be of diagnostic and therapeutic significance. The research of lipidomics in tumor is more and more important. Mass spectrometry like matrix-assisted laser desorption ionization-mass spectrometry (MALDI-MS) can be more convenient and informative for lipids researching in biological and clinical researches. Most of malignant tumors like glioblastoma are characterized by incomplete differentiation, so differentiation therapy has made important progress in tumor treatment. Lipid profiles changes after therapy are worthy investigating. In our study, glioblastoma cell line U87-MG cells were treated by inducers of sodium phenylbutyrate (SPB) and all-trans retinoic acid (ATRA). The changes in lipids on cell membrane were profiled by MALDI-MS. The differentiation degree was assessed by cell proliferation, cell cycle, morphology and protein expression before MALDI-MS analysis. Comparing the inducer treated and untreated U87-MG cells, reduced proliferation rate, blocked cell cycle, benign nucleus morphology and changed expression of protein CD133 and glial fibrillary acidic protein (GFAP), were found after drug treatment. Moreover, the lipids of cell membrane presented distinguished differences in the drug treated cells. Most of the glycerophosphocholines (PC) with an increasing abundance are unsaturated PCs (PC (38:1), 816 m/z; PC (36:1), 788 m/z; PC (31:1), 725 m/z), and those decreasing are saturated PCs (PC (32:0), 734 m/z). These results provide the lipidomic differentiation which may be a significant guidance for evaluating the therapeutic effect of tumor therapy.

Aspiration of conjugated bile acids predicts adverse lung transplant outcomes and correlates with airway lipid and cytokine dysregulation

Duodeno-gastroesophageal reflux aspiration is associated with chronic lung allograft dysfunction (CLAD). Reflux aspirate can contain bile acids (BA), functional molecules in the gastro-intestinal tract with emulsifying properties. We sought to determine and quantify the various BA species in airways of the lung transplant recipients to better understand the various effects of aspirated BA that contribute to post-transplantation outcomes. Bronchial washings (BW) were prospectively collected from lung transplant recipients and subsequently assayed by liquid chromatography-mass spectrometry for 13 BA and 25 lipid families. Patients were monitored for CLAD, rejection, inflammation and airway infections. Detectable BA were present in 45/50 patients (90%) at 3 months after transplant. Elevated BA and predominance of conjugated species were independent predictors of CLAD (hazard ratio 7.9; 95% confidence interval 2.7-23.6; p < 0.001 and 7.3; 2.4-22; p < 0.001, respectively) and mortality (hazard ratio 4.4; 1.5-12.7; p=0.007 and 4.8; 1.4-15.8; p=0.01, respectively). High BA associated with increased positive bacterial cultures (60% vs 25%, p=0.02). Primary conjugated species independently correlated with the rate of bacterial cultures during the first-year post-transplant (Beta coefficient: 0.77; 0.28-1.26; p=0.003) and changes in airway lipidome and cytokines. Higher BA levels and predominance of conjugated BA are independent predictors of chronic lung allograft dysfunction, mortality and bacterial infections. Primary conjugated BA are related to distinct changes in airway lipidome and inflammatory cytokines. This elucidates novel evidence into the mechanism following BA aspiration and proposes novel markers for prediction of adverse post-transplant outcomes.

The Colorectal Cancer Lipidome: Identification of a Robust Tumor-Specific Lipid Species Signature

Lipidomic changes were causally linked to metabolic diseases, but the scenario for colorectal cancer (CRC) is less clear. We investigated the CRC lipidome for putative tumor-specific alterations through analysis of 3 independent retrospective patient cohorts from 2 clinical centers, to derive a clinically useful signature. Quantitative comprehensive lipidomic analysis was performed using direct infusion electrospray ionization coupled with tandem mass spectrometry (ESI-MS/MS) and high-resolution mass spectrometry (HR-MS) on matched nondiseased mucosa and tumor tissue in a discovery cohort (n= 106). Results were validated in 2 independent cohorts (n= 28, and n= 20), associated with genomic and clinical data, and lipidomic data from a genetic mouse tumor model (Apc1638N). Significant differences were found between tumor and normal tissue for glycero-, glycerophospho-, and sphingolipids in the discovery cohort. Comparison to the validation collectives unveiled that glycerophospholipids showed high interpatient variation and were strongly affected by preanalytical conditions, whereas glycero- and sphingolipids appeared more robust. Signatures of sphingomyelin and triacylglycerol (TG) species significantly differentiated cancerous from nondiseased tissue in both validation studies. Moreover, lipogenic enzymes were significantly up-regulated in CRC, and FASN gene expression was prognostically detrimental. The TG profile was significantly associated with postoperative disease-free survival and lymphovascular invasion, and was essentially conserved in murine digestive cancer, but not associated with microsatellite status, KRAS or BRAF mutations, or T-cell infiltration. Analysis of the CRC lipidome revealed a robust TG-species signature with prognostic potential. A better understanding of the cancer-associated glycerolipid and sphingolipid metabolism may lead to novel therapeutic strategies.

Nuclear lipidome is altered in amyotrophic lateral sclerosis: A pilot study.

Nucleocytosolic transport, a membrane process, is impaired in motor neurons in amyotrophic lateral sclerosis (ALS). This study analyzes the nuclear lipidome in motor neurons in ALS and examines molecular pathways linked to the major lipid alterations. Nuclei were obtained from the frozen anterior horn of the lumbar spinal cord of ALS patients and age-matched controls. Lipidomic profiles of this subcellular fraction were obtained using liquid chromatography and mass spectrometry. We validated the mechanisms behind presumable lipidomic changes by exploring ALS surrogate models including human motor neurons (derived from ALS lines and controls) subjected to oxidative stress, the hSOD-G93A transgenic mice, and samples from an independent cohort of ALS patients. Among the differential lipid species, we noted 41 potential identities, mostly belonging to phospholipids (particularly ether phospholipids, as plasmalogens), as well as diacylglycerols and triacylglycerides. Decreased expression of alkyldihydroxyacetonephosphate synthase (AGPS)-a critical peroxisomal enzyme in plasmalogen synthesis-is found in motor neuron disease models; this occurs in parallel with an increase in the expression of sterol carrier protein 2 (SCP2) mRNA in ALS and Scp2 levels in G93A transgenic mice. Further, we identified diminished expression of diacylglycerol-related enzymes, such as phospholipase C βI (PLCβI) and protein kinase CβII (PKCβII), linked to diacylglycerol metabolism. Finally, lipid droplets were recognized in the nuclei, supporting the identification of triacylglycerides as differential lipids. Our results point to the potentially pathogenic role of altered composition of nuclear membrane lipids and lipids in the nucleoplasm in the anterior horn of the spinal cord in ALS. Overall, these data support the usefulness of subcellular lipidomics applied to neurodegenerative diseases.

Decreased caveolae in AGPAT2 lacking adipocytes is independent of changes in cholesterol or sphingolipid levels: A whole cell and plasma membrane lipidomic analysis of adipogenesis

BackgroundAdipocytes from lipodystrophic Agpat2−/− mice have impaired adipogenesis and fewer caveolae. Herein, we examined whether these defects are associated with changes in lipid composition or abnormal levels of caveolae-associated proteins. Lipidome changes were quantified in differentiated Agpat2−/− adipocytes to identify lipids with potential adipogenic roles. MethodsAgpat2−/− and wild type brown preadipocytes were differentiated in vitro. Plasma membrane was purified by ultracentrifugation. Number of caveolae and caveolae-associated proteins, as well as sterol, sphingolipid, and phospholipid lipidome were determined across differentiation. ResultsDifferentiated Agpat2−/− adipocytes had decreased caveolae number but conserved insulin signaling. Caveolin-1 and cavin-1 levels were equivalent between Agpat2−/− and wild type adipocytes. No differences in PM cholesterol and sphingolipids abundance were detected between genotypes. Levels of phosphatidylserine at day 10 of differentiation were increased in Agpat2−/− adipocytes. Wild type adipocytes had increased whole cell triglyceride, diacylglycerol, phosphatidylglycerol, phosphatidic acid, lysophosphatidylcholine, lysophosphatidylethanolamine, and trihexosyl ceramide, and decreased 24,25-dihydrolanosterol and sitosterol, as a result of adipogenic differentiation. By contrast, adipogenesis did not modify whole cell neutral lipids but increased lysophosphatidylcholine, sphingomyelin, and trihexosyl ceramide levels in Agpat2−/− adipocytes. Unexpectedly, adipogenesis decreased PM levels of main phospholipids in both genotypes. ConclusionIn Agpat2−/− adipocytes, decreased caveolae is not associated with changes in PM cholesterol nor sphingolipid levels; however, increased PM phosphatidylserine content may be implicated. Abnormal lipid composition is associated with the adipogenic abnormalities of Agpat2 −/− adipocytes but does not prevent insulin signaling.

A 6-month inhalation toxicology study in Apoe\u2212/\u2212 mice demonstrates substantially lower effects of e-vapor aerosol compared with cigarette smoke in the respiratory tract

Cigarette smoking is the major cause of chronic obstructive pulmonary disease. Considerable attention has been paid to the reduced harm potential of nicotine-containing inhalable products such as electronic cigarettes (e-cigarettes). We investigated the effects of mainstream cigarette smoke (CS) and e-vapor aerosols (containing nicotine and flavor) generated by a capillary aerosol generator on emphysematous changes, lung function, and molecular alterations in the respiratory system of female Apoe−/− mice. Mice were exposed daily (3 h/day, 5 days/week) for 6 months to aerosols from three different e-vapor formulations—(1) carrier (propylene glycol and vegetable glycerol), (2) base (carrier and nicotine), or (3) test (base and flavor)—or to CS from 3R4F reference cigarettes. The CS and base/test aerosol concentrations were matched at 35 µg nicotine/L. CS exposure, but not e-vapor exposure, led to impairment of lung function (pressure–volume loop area, A and K parameters, quasi-static elastance and compliance) and caused marked lung inflammation and emphysematous changes, which were confirmed histopathologically and morphometrically. CS exposure caused lung transcriptome (activation of oxidative stress and inflammatory responses), lipidome, and proteome dysregulation and changes in DNA methylation; in contrast, these effects were substantially reduced in response to the e-vapor aerosol exposure. Compared with sham, aerosol exposure (carrier, base, and test) caused a slight impact on lung inflammation and epithelia irritation. Our results demonstrated that, in comparison with CS, e-vapor aerosols induced substantially lower biological and pathological changes in the respiratory tract associated with chronic inflammation and emphysema.

Hepatic lipidomic remodeling in severe obesity manifests with steatosis and does not evolve with non-alcoholic steatohepatitis

Obesity often leads to non-alcoholic fatty liver disease (NAFLD), which can progress from simple steatosis (non-alcoholic fatty liver (NAFL)) to non-alcoholic steatohepatitis (NASH). The accumulation of certain lipid subtypes is linked with worsening metabolic and liver disease, however, specific changes during progression from No-NAFL to NAFL then NASH are unresolved. Herein, we characterise the liver, adipose tissue and plasma lipidome of worsening NAFLD in obesity, and evaluate the utility of plasma lipids as biomarkers of NAFLD. Venous blood, liver, visceral and subcutaneous adipose tissue samples were obtained from 181 patients undergoing bariatric surgery. NAFLD severity was assessed histologically. Lipidomic analysis was performed using liquid chromatography-tandem mass spectrometry. The liver lipidome showed substantial changes with increasing steatosis, with increased triacylglycerols, diacylglycerols and sphingolipids including ceramide, dihydroceramide, hexosyl-ceramide and GM3 ganglioside species. These lipid species were also increased in plasma with increasing hepatic steatosis and showed strong correlations with liver lipids. Adipose tissue lipidomes showed no correlation with NAFLD. There were no significant changes in liver lipids with NASH compared to NAFL. The addition of plasma lipid variables to routine markers yielded significant improvements in diagnostic accuracy for NASH (AUROC 0.667 vs. 0.785, p=0.025). Overall, these data provide a detailed description of the lipidomic changes with worsening NAFLD, showing significant changes with steatosis but no additional changes with NASH. Alterations in the liver lipidome are paralleled by similar changes in plasma. Further investigation is warranted into the potential utility of plasma lipids as non-invasive biomarkers of NAFLD in obesity. Non-alcoholic fatty liver disease (NAFLD) is characterised by distinct changes in the liver lipidome with steatosis. The development of non-alcoholic steatohepatitis (NASH) does not result in further changes in the lipidome. Lipids within body fat do not appear to influence the lipid profile of the liver or blood. Changes in liver lipids are paralleled by changes in blood lipids. This has potential to be developed into a non-invasive biomarker for NAFLD. ACTRN12615000875505.

The fatty acid elongase ELOVL6 regulates bortezomib resistance in multiple myeloma

Resistance to the proteasome inhibitor bortezomib (BTZ) represents a major obstacle in the treatment of multiple myeloma (MM). The contribution of lipid metabolism in the resistance of MM cells to BTZ is mostly unknown. Here we report that levels of fatty acid elongase 6 (ELOVL6) were lower in MM cells from BTZ-nonresponsive vs BTZ-responsive patients and in cultured MM cells selected for BTZ resistance compared with parental counterparts. Accordingly, depletion of ELOVL6 in parental MM cells suppressed BTZ-induced endoplasmic reticulum (ER) stress and cytotoxicity, whereas restoration of ELOVL6 levels in BTZ-resistant MM cells sensitized them to BTZ in tissue culture settings and, as xenografts, in a plasmacytoma mouse model. Furthermore, for the first time, we identified changes in the BTZ-induced lipidome between parental and BTZ-resistant MM cell lines underlying a functional difference in their response to BTZ. We demonstrated that restoration of ELOVL6 levels in BTZ-resistant MM cells resensitized them to BTZ largely via upregulation of ELOVL6-dependent ceramide species, which was a prerequisite for BTZ-induced ER stress and cell death in these cells. Our data characterize ELOVL6 as a major clinically relevant regulator of MM cell resistance to BTZ, which can emerge from the impaired ability of these cells to alter ceramide composition in response to BTZ.

Account and Utilization of Blood Lipid Profiles: Lipid Levels Predicted Hemosporidian Infection in Migrating Northern Saw-Whet Owls of Eastern North America.

Noting lipidomic changes following the parasitism of migrating birds, the metabolic needs of which are primarily fueled by lipids, can deepen our understanding of host-parasite interactions. We identified lipids of migrating Northern saw-whet owls (Aegolius acadicus) using collision-induced dissociation mass spectrometry, compared the lipidomic signatures of hemoparasite-infected and noninfected individuals, and performed cross-validation analyses to reveal associations between parasite infection and lipid levels. We found significantly lower levels of lipid classes phosphatidic acid (PA), phosphatidylglycerol (PG), phosphatidylinositol (PI), phosphatidylserine (PS), phosphatidylethanolamine (PE), phosphatidylcholine (PC), and sphingomyelin (SM) in infected Northern saw-whet owls than in the noninfected individuals. Conversely, we found higher levels for certain lysoPS and lysoPE species, and variable lipid level changes for free fatty acid (FFA) species. Reporting lipidomic changes observed between hemosporidian-infected and noninfected Northern saw-whet owls can strengthen our understanding of the mechanisms governing parasite proliferation in this species. Furthermore, our analysis indicated that lipidomic signatures are better predictors of parasite infection than the log-adjusted mass/wing chord body index, a metric commonly used to assess the influence of hemosporidia infection on the health of birds. Establishing a lipidomic profile for Northern saw-whet owls that provides baseline lipid levels during fall migration may assist future studies assessing causes of reductions in breeding brought about from subtle differences in behaviors such as delayed migration.

Metabolic Changes in Brain Slices over Time: a Multiplatform Metabolomics Approach.

Brain slice preparations are widely used for research in neuroscience. However, a high-quality preparation is essential and there is no consensus regarding stable parameters that can be used to define the status of the brain slice preparation after its collection at different time points. Thus, it is critical to fully characterize the experimental conditions for ex vivo studies using brain slices for electrophysiological recording. In this study, we used a multiplatform (LC-MS and GC-MS) untargeted metabolomics-based approach to shed light on the metabolome and lipidome changes taking place at different time intervals during the brain slice preparation process. We have found significant modifications in the levels of 300 compounds, including several lipid classes and their derivatives, as well as metabolites involved in the GABAergic pathway and the TCA cycle. All these preparation-dependent changes in the brain biochemistry related to the time interval should be taken into consideration for future studies to facilitate non-biased interpretations of the experimental results.

48352 Mechanisms Underlying Lipidomic Changes in Major Depressive Disorder

ABSTRACT IMPACT: Lipidomics is emerging as a powerful strategy to identify biomarkers for Major Depressive Disorder, as well as therapeutic targets in lipid metabolic pathways. OBJECTIVES/GOALS: Lipidomics is increasingly recognized in precision psychiatry for global lipid perturbations in patients suffering from Major Depressive Disorder (MDD). We will test the hypothesis that lipid metabolism dysregulation is associated with familial risk of depression. METHODS/STUDY POPULATION: Patients with MDD (G1), children (G2), and grandchildren (G3) have been part of a longitudinal study since 1982. If a parent G2 and grandparent G1 have MDD, G3 is considered a high risk of depression. Biospecimens (saliva and serum) were collected for full exome sequencing and RNA analysis. Samples will also be extracted for lipid content and lipids will be identified by mass spectrometry. A panel of nearly 600 lipid species can reliably be identified and quantified using liquid chromatography paired with tandem mass spectrometry (LC-MS/MS). Dysregulated lipids will be correlated with familial risk of depression in samples of G3. RESULTS/ANTICIPATED RESULTS: We hypothesize that dysregulation of lipids and lipid metabolism will be apparent in biospecimens from the high risk compared to the low risk of depression. Also, alterations in RNA transcriptomics of genes involved in lipid metabolic networks are associated with familial risk of depression. Several differential lipid species were previously identified to be associated with MDD. Reduced phosphatidylcholine(PC), phosphatidylethanolamine(PE), phosphatidylinositol(PI), and increased LysoPC, LysoPE, ceramide, triacylglycerol, and diacylglycerol levels have been correlated to MDD. However, these results need to be replicated in independent studies using lipidomics analysis. DISCUSSION/SIGNIFICANCE OF FINDINGS: It is highly likely that completely novel cellular targets will emerge from these studies by uncovering the convergence of lipidomics and genetic variance of lipid metabolic enzymes as biomarkers for predisposition to MDD as well as potential targets for therapeutic development for MDD.

Obesity-Related Changes in Human Plasma Lipidome Determined by the Lipidyzer Platform.

Obesity is an increasing public health concern both in the developed and developing countries. Previous studies have demonstrated that considerable alterations in lipid metabolism and consequently marked changes in lipid profile are associated with the onset and progression of obesity-related complications. To characterize the full spectrum of obesity-induced changes in lipid metabolism, direct infusion tandem mass spectrometry analysis is the most promising approach. To better understand which of the many lipid species are the most strongly associated with obesity, the aim of our work was to measure and profile plasma lipids in normal (n = 57), overweight (n = 31), and obese (n = 48) individuals randomly selected from samples of Hungarian general and Roma populations by using the targeted quantitative lipidomics platform, the Lipidyzer. Principal component and stepwise regression analyses were used to identify the most significant clusters and species of lipids by increasing body mass index (BMI). From the 18 clusters identified four key lipid species (PE P-16:0/20:3, TG 20:4_33:1, TG 22:6_36:4, TG 18:3_33:0) showed a strong significant positive and three others (Hex-Cer 18:1;O2/22:0, LPC 18:2, PC 18:1_18:1) significant negative association with BMI. Compared to individual lipid species alone, the lipid species ratio (LSR) we introduced showed an extremely strong, at least 9 orders of magnitude stronger, association with BMI. The LSR can be used as a sensitive and predictive indicator to monitor obesity-related alterations in human plasma and control the effectiveness of treatment of obesity associated non-communicable diseases.

Whole Community Metatranscriptomes and Lipidomes Reveal Diverse Responses Among Antarctic Phytoplankton to Changing Ice Conditions

The transition from winter to spring represents a major shift in the basal energy source for the Antarctic marine ecosystem from lipids and other sources of stored energy to sunlight. Because sea ice imposes a strong control on the transmission of sunlight into the water column during the polar spring, we hypothesized that the timing of the sea ice retreat influences the timing of the transition from stored energy to photosynthesis. To test the influence of sea ice on water column microbial energy utilization we took advantage of unique sea ice conditions in Arthur Harbor, an embayment near Palmer Station on the western Antarctic Peninsula, during the 2015 spring–summer seasonal transition. Over a 5-week period we sampled water from below land-fast sea ice, in the marginal ice zone at nearby Palmer Station B, and conducted an ice removal experiment with incubations of water collected below the land-fast ice. Whole-community metatranscriptomes were paired with lipidomics to better understand how lipid production and utilization was influenced by light conditions. We identified several different phytoplankton taxa that responded similarly to light by the number of genes up-regulated, and in the transcriptional complexity of this response. We applied a principal components analysis to these data to reduce their dimensionality, revealing that each of these taxa exhibited a strikingly different pattern of gene up-regulation. By correlating the changes in lipid concentration to the first principal component of log fold-change for each taxa we could make predictions about which taxa were associated with different changes in the community lipidome. We found that genes coding for the catabolism of triacylglycerol storage lipids were expressed early on in phytoplankton associated with a Fragilariopsis kerguelensis reference transcriptome. Phytoplankton associated with a Corethron pennatum reference transcriptome occupied an adjacent niche, responding favorably to higher light conditions than F. kerguelensis. Other diatom and dinoflagellate taxa had distinct transcriptional profiles and correlations to lipids, suggesting diverse ecological strategies during the polar winter–spring transition.

Plasma lipidome of healthy and Rhodococcus equi-infected foals over time.

Many foals that develop thoracic ultrasonographic lesions as a result of Rhodococcus equi infection heal on their own. However, most of these foals receive antimicrobials because foals at risk of developing clinical pneumonia cannot be identified. Untargeted lipidomics is useful to identify candidate biomarkers. (a) To describe the changes that occur in foal lipidomics as a result of ageing (birth to 8weeks) and (b) To compare these results with those observed in foals after experimental infection with R. equi. Experimental study. Healthy newborn foals (n=9) were challenged with R. equi intratracheally the first week of life. Foals were treated with antimicrobials if they developed clinical pneumonia (n=4, "clinical group") or were closely monitored if they showed no signs of disease (n=5 "subclinical group"). An unchallenged group (n=4) was also included. All foals were free of disease (transtracheal wash fluid evaluation and culture as well as thoracic ultrasonography) by 8weeks of life. Plasma lipidomics was determined by LC-MS weekly for the study duration (8weeks). Both ageing and experimental infection altered the foal's plasma lipidome as demonstrated by multivariate statistical analysis. The intensities of 31 lipids were altered by ageing and 12 by infection (P<.05). Furthermore, nine lipids changed by more than twofold between clinical and subclinical groups. The number of foals is limited. Foals were experimentally challenged with R. equi. Ageing and R. equi infection induced changes in the plasma lipidome of foals. These experimental results provide the background for future work in the discovery of earlier biomarkers of R. equi pneumonia. Early identification of foals at risk of developing clinical pneumonia is key in order to decrease antimicrobial use and development of antimicrobial resistance.

Ether lipids, sphingolipids and toxic 1-deoxyceramides as hallmarks for lean and obese type 2 diabetic patients.

The worldwide increase in obesity and type 2 diabetes (T2D) represents a major health challenge. Chronically altered lipids induced by obesity further promote the development of T2D, and the accumulation of toxic lipid metabolites in serum and peripheral organs may contribute to the diabetic phenotype. To better understand the complex metabolic pattern of lean and obese T2D and non-T2D individuals, we analysed the lipid profile of human serum, skeletal muscle and visceral adipose tissue of two cohorts by systematic mass spectrometry-based lipid analysis. Lipid homeostasis was strongly altered in a disease- and tissue-specific manner, allowing us to define T2D signatures associated with obesity from those that were obesity independent. Lipid changes encompassed lyso-, diacyl- and ether-phospholipids. Moreover, strong changes in sphingolipids included cytotoxic 1-deoxyceramide accumulation in a disease-specific manner in serum and visceral adipose tissue. The high amounts of non-canonical 1-deoxyceramide present in human adipose tissue most likely come from cell-autonomous synthesis because 1-deoxyceramide production increased upon differentiation to adipocytes in mouse cell culture experiments. Taken together, the observed lipidome changes in obesity and T2D will facilitate the identification of T2D patient subgroups and represent an important step towards personalized medicine in diabetes.

Changes in Key Mitochondrial Lipids Accompany Mitochondrial Dysfunction and Oxidative Stress in NAFLD.

Nonalcoholic fatty liver disease (NAFLD) is a dysmetabolic hepatic damage of increasing severity: simple fat accumulation (steatosis), nonalcoholic steatohepatitis (NASH), and hepatic fibrosis. Oxidative stress is considered an important factor in producing hepatocyte injury associated with NAFLD progression. Studies also suggest a link between the accumulation of specific hepatic lipid species, mitochondrial dysfunction, and the progression of NAFLD. However, it is unclear whether mitochondrial lipid modifications are involved in NAFLD progression. To gain insight into the relationship between mitochondrial lipids and disease progression through different stages of NAFLD, we performed lipidomic analyses on mouse livers at different stages of western diet-induced NAFLD, with or without hepatic fibrosis. After organelle separation, we studied separately the mitochondrial and the “nonmitochondrial” hepatic lipidomes. We identified 719 lipid species from 16 lipid families. Remarkably, the western diet triggered time-dependent changes in the mitochondrial lipidome, whereas the “nonmitochondrial” lipidome showed little difference with levels of hepatic steatosis or the presence of fibrosis. In mitochondria, the changes in the lipidome preceded hepatic fibrosis. In particular, two critical phospholipids, phosphatidic acid (PA) and cardiolipin (CL), displayed opposite responses in mitochondria. Decrease in CL and increase in PA were concurrent with an increase of coenzyme Q. Electron paramagnetic resonance spectroscopy superoxide spin trapping and Cu2+ measurement showed the progressive increase in oxidative stress in the liver. Overall, these results suggest mitochondrial lipid modifications could act as an early event in mitochondrial dysfunction and NAFLD progression.

Lacritin proteoforms prevent tear film collapse and maintain epithelial homeostasis

Lipids in complex, protein-enriched films at air/liquid interfaces reduce surface tension. In the absence of this benefit, the light refracting and immunoprotective tear film on eyes would collapse. Premature collapse, coupled with chronic inflammation compromising visual acuity, is a hallmark of dry eye disease affecting 7 to 10% of individuals worldwide. Although collapse seems independent of mutation (unlike newborn lung alveoli), selective proteome and possible lipidome changes have been noted. These include elevated tissue transglutaminase and consequent inactivation through C-terminal cross-linking of the tear mitogen lacritin, leading to significant loss of lacritin monomer. Lacritin monomer restores homeostasis via autophagy and mitochondrial fusion and promotes basal tearing. Here, we discover that lacritin monomer C-terminal processing, inclusive of cysteine, serine, and metalloproteinase activity, generates cationic amphipathic α-helical proteoforms. Such proteoforms (using synthetic peptide surrogates) act like alveolar surfactant proteins to rapidly bind and stabilize the tear lipid layer. Immunodepletion of C- but not N-terminal proteoforms nor intact lacritin, from normal human tears promotes loss of stability akin to human dry eye tears. Stability of these and dry eye tears is rescuable with C- but not N-terminal proteoforms. Repeated topical application in rabbits reveals a proteoform turnover time of 7 to 33 h with gradual loss from human tear lipid that retains bioactivity without further processing. Thus, the processed C-terminus of lacritin that is deficient or absent in dry eye tears appears to play a key role in preventing tear film collapse and as a natural slow release mechanism that restores epithelial homeostasis.

Lipidomic Signature of Changes in Adiposity: A Large Prospective Study of 5,849 Adults from the Australian Diabetes, Obesity and Lifestyle Study

Background: Lipid metabolism is tightly linked to adiposity and weight gain. Comprehensive lipidomic profiling offers new insights into the dysregulation of lipid metabolism in relation to weight gain. Here, we investigated the relationship of the human plasma lipidome and changes in waist circumference (WC) and body mass index (BMI). Methods: Adults (2,653 men and 3,196 women), 25-95 years old who attended the baseline survey of the Australian Diabetes, Obesity and Lifestyle Study (AusDiab) and the 5-year follow-up were enrolled. A targeted lipidomic approach was used to quantify 706 distinct molecular lipid species in the plasma samples. Multiple linear regression models were used to examine the relationship between the baseline lipidomic profile and changes in WC and BMI. Metabolic scores for change in WC were generated using a ridge regression model. Findings: Alkyl-diacylglycerol such as TG(O-50:2) [NL-18:1] displayed the strongest association with change in WC (β-coefficient = 0.125 cm increment per SD increment in baseline lipid level, p = 2.78E-11). Many lipid species containing linoleate (18:2) fatty acids were negatively associated with both WC and BMI gain. Compared to traditional models, multivariate models containing lipid species identify individuals at a greater risk of gaining WC: top quintile relative to bottom quintile (odds ratio, 95% CI = 5.4, 3.8 – 6.6 for women and 2.3, 1.7 – 3.0 for men). Interpretation: Our findings define metabolic profiles that characterise individuals at risk of weight gain or WC increase and provide important insight into the biological role of lipids in obesity. Funding: National Health and Medical Research Council of Australia (Project grant APP1101320) and the Victorian Government’s Operational Infrastructure Support Program. Declaration of Interest: The authors declare no conflicts of interest Ethical Approval: The study was approved by the Human Research Ethics Committee at the Alfred Hospital, Melbourne, Australia.

From Prevention to Disease Perturbations: A Multi-Omic Assessment of Exercise and Myocardial Infarctions.

While a molecular assessment of the perturbations and injury arising from diseases is essential in their diagnosis and treatment, understanding changes due to preventative strategies is also imperative. Currently, complex diseases such as cardiovascular disease (CVD), the leading cause of death worldwide, suffer from a limited understanding of how the molecular mechanisms taking place following preventive measures (e.g., exercise) differ from changes occurring due to the injuries caused from the disease (e.g., myocardial infarction (MI)). Therefore, this manuscript assesses lipidomic changes before and one hour after exercise treadmill testing (ETT) and before and one hour after a planned myocardial infarction (PMI) in two separate patient cohorts. Strikingly, unique lipidomic perturbations were observed for these events, as could be expected from their vastly different stresses on the body. The lipidomic results were then combined with previously published metabolomic characterizations of the same patients. This integration provides complementary insights into the exercise and PMI events, thereby giving a more holistic understanding of the molecular changes associated with each.