Lipid droplets (LDs) are composed of neutral lipids enclosed in a phospholipid monolayer, which harbors membrane-associated proteins that regulate LD functions. Despite the crucial role of LDs in lipid metabolism, remodeling of LD protein composition in disease contexts, such as steatosis, remains poorly understood. We hypothesized that chronic ethanol (EtOH) consumption, subsequent abstinence from

Lipidomics data require consideration of ions with near-identical masses, which comprises amongst others the Type-II isotopic overlap. This overlap occurs in series of lipid species differing only by number of double bonds (DB) mainly due to the natural abundance of 13C-atoms. High-resolution mass spectrometry, such as Fourier-Transform mass spectrometry (FTMS), is capable of resolving Type-II overlap

HDL and its primary receptor, scavenger receptor BI (SR-BI), work together to promote the clearance of excess plasma cholesterol, thereby protecting against atherosclerosis. Human variants of SR-BI have been identified in patients with high HDL-cholesterol levels, and at least one variant has been linked to cardiovascular disease. Therefore, while often regarded as beneficial, very high levels of HDL-cholesterol

Lipids play essential roles in maintaining cell structure and function by modulating membrane fluidity and cell signaling. The fatty acid elongase-4 (ELOVL4) protein - expressed in retina, brain, Meibomian glands, skin, testes and sperm - is an essential enzyme that mediates tissue-specific biosynthesis of both VLC-PUFA and VLC-saturated fatty acids (VLC-SFA). These fatty acids play critical roles

The enzyme 3β-hydroxysterol-Δ24 reductase (DHCR24, EC 1.3.1.72) catalyzes the conversion of desmosterol to cholesterol, and is obligatory for post-squalene cholesterol synthesis. Genetic loss of this enzyme results in Desmosterolosis (MIM #602398), a rare disease that presents with multiple congenital anomalies, features of which overlap with subjects with the Smith-Lemli-Opitz syndrome (another post-squalene

Lysophosphatidic acid (LPA) is a potent signaling lipid, and state-dependent alterations in LPA make it a promising diagnostic marker for various diseases. However, plasma LPA concentrations vary widely among reports, even under normal conditions. These variations can be attributed, at least in part, to the artificial metabolism of LPA after blood collection, thus complicating the use of plasma LPA

Cholesteryl ester transfer protein (CETP) modulates lipoprotein metabolism by transferring cholesteryl ester (CE) and triglyceride (TG) between lipoproteins. However, differences in the way CETP functions exist across species. Unlike human CETP, hamster CETP prefers TG over CE as a substrate, raising questions regarding how substrate preference may impact lipoprotein metabolism. To understand how altering

Epidermal growth factor receptor (EGFR) signaling drives the formation of many types of cancer, including colon cancer. Docosahexaenoic acid (DHA, 22∶6Δ4,7,10,13,16,19), a chemoprotective long chain n-3 polyunsaturated fatty acid (PUFA) suppresses EGFR signaling. However, the mechanism underlying this phenotype remains unclear. Therefore, we used super-resolution microscopy techniques to investigate

Phospholipids with a choline head group are an abundant component of cellular membranes and are involved in many important biological functions. For studies on the cell biology and metabolism of these lipids traceable analogues where propargylcholine replaces the choline head group have proven useful. We present a novel method to analyze propargylcholine phospholipids by mass spectrometry. The routine

Mass spectrometry imaging (MSI) visualises molecular distributions throughout tissues but is blind to dynamic metabolic processes. Here, MSI with high mass resolution together with multiple stable isotope labelling provided spatial analyses of phosphatidylcholine (PC) metabolism in mouse lungs. Dysregulated surfactant metabolism is central to many respiratory diseases. Metabolism and turnover of therapeutic

Oxidative stress promotes acute kidney injury (AKI). Higher concentrations of HDL cholesterol are associated with less AKI. To test the hypothesis that HDL antioxidant activity is associated with AKI after cardiac surgery, we quantified HDL particle size and number, paraoxonase-1 activity, and isofuran concentrations in 75 patients who developed AKI and 75 matched control patients. Higher preoperative

Microtubules are polymers composed of αβ-tubulin subunits that provide structure to cells and play a crucial role in in the development and function of neuronal processes and cilia, microtubule-driven extensions of the plasma membrane that have sensory (primary cilia) or motor (motile cilia) functions. To stabilize microtubules in neuronal processes and cilia, α tubulin is modified by the posttranslational

Deficiency of glucocerebrosidase (GBA), a lysosomal β-glucosidase, causes Gaucher disease. The enzyme hydrolyzes β-glucosidic substrates and transglucosylates cholesterol to cholesterol-β-glucoside. Here we show that recombinant human GBA also cleaves β-xylosides and transxylosylates cholesterol. The xylosyl-cholesterol formed acts as acceptor for subsequent formation of di-xylosyl-cholesterol. Common

Lipid metabolic abnormalities have emerged as potential risk factors for the development and progression of diabetic complications, including diabetic retinopathy (DR). This review article provides an overview of the results of clinical trials evaluating the potential benefits of lipid lowering drugs, such as fibrates, omega 3 fatty acids, and statins, for the prevention and treatment of DR. Although

Carotid atherosclerosis is a risk factor for ischemic stroke, one of the main causes of mortality and disability worldwide. The disease is characterized by plaques, heterogeneous deposits of lipids and necrotic debris in the vascular wall, which grow gradually and may remain asymptomatic for decades. However, at some point a plaque can evolve to a high-risk plaque phenotype, which may trigger a cerebrovascular

Genome-wide association studies (GWAS) have implicated ~380 genetic loci for plasma lipid regulation. However, these loci only explain 17-27% of the trait variance and a comprehensive understanding of the molecular mechanisms has not been achieved. In this study, we utilized an integrative genomics approach leveraging diverse genomic data from human populations to investigate whether genetic variants

Perilipin (PLIN) 5 is a lipid droplet-associated protein that coordinates intracellular lipolysis in highly oxidative tissues and is thought to regulate lipid metabolism in response to phosphorylation by protein kinase A (PKA). We sought to identify PKA phosphorylation sites in PLIN5 and assess their functional relevance in cultured cells and the livers of mice. We detected phosphorylation on S155

Recent studies have highlighted an important role for lysophosphatidylcholine acyltransferase 3 (LPCAT3) in controlling the PUFA composition of cell membranes in the liver and intestine. In these organs, LPCAT3 critically supports cell membrane-associated processes such as lipid absorption or lipoprotein secretion. However, the role of LPCAT3 in macrophages remains controversial. Here, we investigated

Apolipoproteins C-I, C-II and C-III interact with ApoE to regulate lipoprotein metabolism and contribute to Alzheimer's disease pathophysiology. In plasma, apoC-I and C-II exist as truncated isoforms, while apoC-III exhibits multiple glycoforms. This study aimed to 1. delineate apoC-I, C-II and C-III isoform profiles in CSF and plasma in a cohort of non-demented older individuals (n = 61), and 2. examine

The LDL receptor-related protein-1 (LRP1) is highly expressed in numerous cell types, and its impairment is associated with obesity, diabetes, and fatty liver disease. However, the mechanisms linking LRP1 to metabolic disease are not completely understood. Here, we compared the metabolic phenotype of C57BL/6J wild type and LRP1 knock-in mice carrying an inactivating mutation in the distal NPxY motif

Bacterial lipopolysaccharides (LPSs or endotoxins) can bind most proteins of the lipid transfer/LPS-binding protein (LT/LBP) family in host organisms. The LPS-bound LT/LBP proteins then trigger either an LPS-induced proinflammatory cascade or LPS binding to lipoproteins that are involved in endotoxin inactivation and detoxification. Cholesteryl ester transfer protein (CETP) is an LT/LBP member, but

Lecithin:cholesterol-acyl-transferase (LCAT) plays a major role in cholesterol metabolism as it is the only extracellular enzyme able to esterify cholesterol. LCAT activity is required for lipoprotein remodelling and, most specifically, for the growth and maturation of HDLs. In fact, genetic alterations affecting LCAT func- tionality may cause a severe reduction in plasma levels of HDL-cholesterol

Apolipoprotein A-I (ApoA-I) of high-density lipoprotein (HDL) is essential for the transportation of cholesterol between peripheral tissues and the liver. However, specific mutations in Apolipoprotein A-I (ApoA-I) of high-density lipoprotein (HDL) are responsible for a late-onset systemic amyloidosis, the pathological accumulation of protein fibrils in tissues and organs. Carriers of these mutations

Proprotein convertase subtilisin/kexin type 9 (PCSK9) regulates cholesterol metabolism by inducing the degradation of hepatic low-density lipoprotein receptor (LDLR). Plasma PCSK9 has two main molecular forms: a 62-kDa mature form (PCSK9_62) and a 55-kDa, furin-cleaved form (PCSK9_55). PCSK9_55 is considered less active than PCSK9_62 in degrading LDLR. We aimed to identify the site of PCSK9_55 formation

Smith-Lemli-Opitz Syndrome (SLOS) is a developmental disorder (OMIM #270400) caused by autosomal recessive mutations in the Dhcr7 gene, which encodes the enzyme 3β-hydroxysterol-∆7 reductase. SLOS patients present clinically with dysmorphology and neurological, behavioral and cognitive defects, with characteristically elevated levels of 7-dehydrocholesterol (7-DHC) in all bodily tissues and fluids

Adiponectin, an adipocyte-derived protein, has anti-atherogenic and anti-diabetic effects, but how it confers the anti-atherogenic effects is not well understood. To study the anti-atherogenic mechanisms of adiponectin, we examined whether it interacts with atherogenic low-density lipoprotein (LDL) to attenuate LDL's atherogenicity. L5, the most electronegative subfraction of LDL, induces atherogenic

Spatial changes of fatty acids in the retina in response to different dietary n-3 formulations have never been explored, although a diet rich in EPA and DHA is recommended to protect the retina against the effects of aging. In this study, Wistar rats were fed for 8 weeks with balanced diet including either EPA-containing phospholipids, EPA-containing triglycerides, DHA-containing phospholipids, or

The essential fatty acid DHA (22:6, omega-3 or n-3) is enriched in and required for the membrane biogenesis and function of photoreceptor cells (PRC), synapses, mitochondria, etc. of the CNS. PRC DHA becomes an acyl chain at the sn-2 of phosphatidylcholine (PC), amounting to more than 50% of the PRC outer segment phospholipids, where phototransduction takes place. Very long chain PUFAs (VLC-PUFAs,n-3

HMG-CoA Reductase (Hmgcr) is the rate-limiting enzyme in the mevalonate pathway and is inhibited by statins. In addition to cholesterol, Hmgcr activity is also required for synthesizing non-sterol isoprenoids, such as dolichol, ubiquinone, farnesylated and geranylgeranylated proteins. Here, we investigated the effects of Hmgcr inhibition on non-sterol isoprenoids in the liver. We have generated new

Roux-en-Y gastric bypass (RYGB) is one of the most commonly performed weight-loss procedures, but how severe obesity and RYGB affects circulating HDL-associated microRNAs (miRNAs) remains unclear. Here, we aim to investigate how HDL-associated miRNAs are regulated in severe obesity and how weight loss after RYGB surgery affects HDL-miRNAs. Plasma HDL were isolated from patients with severe obesity

Cholesterol is a quantitatively and biologically significant constituent of all mammalian cell membrane, including those that comprise the retina. Retinal cholesterol homeostasis entails the interplay between de novo synthesis, uptake, intra-retinal sterol transport, metabolism and efflux. Defects in these complex processes are associated with several congenital and age-related disorders of the visual

Lipopolysaccharide (LPS) is a key player for innate immunity activation. It is therefore a prime target for sepsis treatment, as antibiotics are not sufficient to improve outcome during septic shock. Extracorporeal removal method by polymyxin B hemoperfusion (PMX-DHP) is used in Japan, but recent trials failed to show a significant lowering of circulating LPS levels after PMX-DHP therapy. PMX-DHP has

A comprehensive and standardized system to report lipid structures analyzed by mass spectrometry is essential for the communication and storage of lipidomics data. Herein, an update on both the LIPID MAPS classification system and shorthand notation of lipid structures is presented for lipid categories Fatty Acyls (FA), Glycerolipids (GL), Glycerophospholipids (GP), Sphingolipids (SP), and Sterols

Nonalcoholic fatty liver disease (NAFLD) is an important public health issue closely associated with the pervasive epidemics of diabetes and obesity. Yet, despite NAFLD being among the most common of chronic liver diseases, the biological factors responsible for its transition from benign nonalcoholic fatty liver (NAFL) to nonalcoholic steatohepatitis (NASH) remain unclear. This lack of knowledge leads

Of the known regulators of atherosclerosis, miRNAs have been demonstrated to play critical roles in lipoprotein homeostasis and plaque formation. Here, we generated a novel animal model of atherosclerosis by knocking-in LDLRW483X in C57BL/6 mice, as the W483X mutation in LDLR is considered the most common, newly identified pathogenic mutation in Chinese familial hypercholesterolemia (FH) individuals

Familial LCAT deficiency (FLD) is a rare genetic disorder of HDL metabolism, caused by loss-of-function mutations in the LCAT gene and characterized by a variety of symptoms including corneal opacities and kidney failure. Renal disease represents the leading cause of morbidity and mortality in FLD cases. However, the prognosis is not known and the rate of deterioration of kidney function is variable

Phospholipids, including ether phospholipids, are composed of numerous isomeric and isobaric species that have the same backbone and acyl chains. This structural resemblance results in similar fragmentation patterns by collision-induced dissociation of phospholipids regardless of class, yielding complicated tandem mass spectrometry (MS/MS) spectra when isobaric species are analyzed together. Furthermore

Lipins are eukaryotic proteins with functions in lipid synthesis and the homeostatic control of energy balance. They execute these functions by acting as phosphatidate phosphatase enzymes in the cytoplasm and by changing gene expression after translocation into the cell nucleus, in particular under fasting conditions. Here, we asked whether nuclear translocation and enzymatic activity of Drosophila

The dysregulation of myeloid-derived cell metabolism can drive atherosclerosis. AMP-activated protein kinase (AMPK) controls various aspects of macrophage dynamics and lipid homeostasis, which are important during atherogenesis. Using LysM-Cre to drive the deletion of both the α1 and α2 catalytic subunits (MacKO), we aimed to clarify the role of myeloid-specific AMPK signaling in male and female mice

Beiging of white adipose tissue has beneficial effects on metabolism. Although it is known that beige adipocytes are active in lipid catabolism and thermogenesis, how it is regulated deserve more explorations. In this study, we demonstrate that stearoyl-CoA desaturase 1 (SCD1) in subcutaneous white adipose tissue (scWAT) responded to cold stimulation and was able to promote mobilization of triglyceride

Recently, human genetic studies identified an association of single-nucleotide polymorphisms (SNPs) in the HSD17B13 (17-beta hydroxysteroid dehydrogenase 13) gene with alcoholic and nonalcoholic fatty liver disease (NAFLD) development. Mutant HSD17B13 variants devoid of enzymatic function have been demonstrated to be protective from cirrhosis and liver cancer, supporting the development of HSD17B13

Phosphatidate phosphatase catalyzes the penultimate step in the synthesis of triacylglycerol and regulates the synthesis of membrane phospholipids. There is much interest in this enzyme because it controls the cellular levels of its substrate phosphatidate and product diacylglycerol; defects in the metabolism of these lipid intermediates are the basis for lipid-based diseases such as obesity, lipodystrophy

Atherosclerosis is characterized by the pathological accumulation of cholesterol-laden macrophages in the arterial wall. Atherosclerosis is also the main underlying cause of cardiovascular diseases (CVDs), and its development is largely driven by elevated plasma cholesterol. Strong epidemiological data find an inverse association between plasma β-carotene with atherosclerosis, and we recently showed

The plasma membrane of neurons consists of distinct domains, each of which carries specialized functions and a characteristic set of membrane proteins. While this compartmentalized membrane organization is essential for neuronal functions, it remains controversial how neurons establish these domains on the laterally fluid membrane. Here, using immunostaining, lipid-MS analysis and gene ablation with

Some cases of chylomicronemia are caused by autoantibodies against GPIHBP1, an endothelial cell protein that shuttles lipoprotein lipase (LPL) to the capillary lumen. GPIHBP1 autoantibodies prevent binding and transport of LPL by GPIHBP1, thereby disrupting the lipolytic processing of triglyceride-rich lipoproteins. Here, we review the "GPIHBP1 autoantibody syndrome" and summarize clinical and laboratory

Sphingolipids have emerged as bioactive lipids involved in the regulation of many physiological and pathological processes. In the retina, they have been established to participate in numerous processes, such as neuronal survival and death, proliferation and migration of neuronal and vascular cells, inflammation, and neovascularization. Dysregulation of sphingolipids is, therefore, crucial in the onset

Xanthophyllomyces dendrorhous is a basidiomycete yeast that produces carotenoids, mainly astaxanthin. Astaxanthin is an organic pigment of commercial interest due to its antioxidant and coloring properties. X. dendrorhous has a functional Sterol Regulatory Element-Binding Protein (SREBP) pathway, and the Sre1 protein is the SREBP homolog in this yeast. However, how Sre1 is promoting the biosynthesis

ABCB4/MDR3 is located in the canalicular membrane of hepatocytes and translocates phosphatidylcholine (PC) lipids from the cytoplasmic to the extracellular leaflet. ABCB4 is an ATP-dependent transporter that reduces the harsh detergent effect of the bile salts by counteracting self-digestion. To do so ABCB4 provides PC-lipids for extraction into bile. PC-lipids account for 40% of the entire pool of

Porphyromonas gingivalis is a Gram-negative anaerobic periodontal microorganism strongly associated with tissue destructive processes in human periodontitis. Following oral infection with P. gingivalis, the periodontal bone loss in mice is reported to require engagement of Toll-like receptor 2 (TLR2). Serine-glycine lipodipeptide or glycine aminolipid classes of P. gingivalis engage human and mouse

Microsomal triglyceride transfer protein (MTTP) deficiency results in a syndrome of hypolipidemia and accelerated nonalcoholic fatty liver disease (NAFLD). Animal models of decreased hepatic MTTP activity have revealed an unexplained dissociation between hepatic steatosis and hepatic insulin resistance. Here, we performed comprehensive metabolic phenotyping of liver specific MTTP knockout (L-Mttp-/-)

Lipoproteins play a key role in transport of cholesterol to and from tissues. Recent studies have also demonstrated that red blood cells (RBCs), which carry large quantities of free cholesterol in their membrane, play an important role in reverse cholesterol transport. However, the exact role of RBCs in systemic cholesterol metabolism is poorly understood. RBCs were incubated with autologous plasma

Lipoprotein (a) [Lp(a)] is characterized by an LDL-like composition in terms of lipids and apoB100, and by one copy of a unique glycoprotein, apolipoprotein (a) [apo(a)]. The apo(a) structure is mainly based on the repetition of tandem kringle domains with high homology to plasminogen kringles 4 and 5. Among them, kringle IV type 2 (KIV-2) is present in a highly variable number of genetically encoded

Mendelian randomization (MR) of lipid traits in coronary artery disease (CAD) has provided evidence for causal associations of low-density lipoprotein cholesterol (LDL-C) and triglycerides (TG) in CAD, but many lipid trait genetic variants have pleiotropic effects on other cardiovascular risk factors that may bias MR associations. The goal of this study was to evaluate pleiotropic effects of lipid

Fabry disease is caused by deficient activity of α-galactosidase A-an enzyme that hydrolyses the terminal α-galactosyl moieties from glycolipids and glycoproteins--and subsequent accumulation of glycosphingolipids, mainly globotriaosylceramide (Gb3), globotriaosylsphingosine (lyso-Gb3) and galabiosylceramide. However, there is no known link between these compounds and disease severity. In this study

Genetic variants that increase the risk of fatty liver disease (FLD) and cirrhosis have recently been identified in the proximity of membrane bound O-acyltransferase domain-containing 7 (MBOAT7). To elucidate the link between these variants and FLD we characterized Mboat7 liver-specific knock-out mice (Mboat7-LSKO). Chow-fed Mboat7-LSKO mice developed fatty livers and associated liver injury. Lipidomic

The rise of drug-resistant tuberculosis (TB) poses a major risk to public health. Statins, which inhibit both cholesterol biosynthesis and protein prenylation branches of the mevalonate pathway, increase anti-tubercular antibiotic efficacy in animal models. However, the underlying molecular mechanisms are unknown. In this study, we used an in vitro macrophage infection model to investigate simvastatin's

Oxylipins are potent lipid mediators involved in a variety of physiological processes. Their profiling has the potential to provide a wealth of information regarding human health and disease and is a promising technology for translation into cli