Search Results (48)

Background: Myristic acid (MA), a 14-carbon saturated fatty acid, serves as a precursor for the synthesis of non-canonical d16-sphingoid bases via its activated form, C14:0-CoA. However, its broader regulatory role in sphingolipid (SL) metabolism remains poorly defined. Methods: Using HepG2 cells treated with 50 μM MA, we found that sphingolipidomic analysis revealed reprogrammed sphingolipid metabolism. Results: In the canonical d18-SL pathway, MA directs its activated product C14:0-CoA into ceramide N-acyl chains and downstream metabolites—especially d18:1-C14:0 hexosylceramide. Concurrently, in the non-canonical d16-SL pathway, MA promotes d16-SL synthesis, especially d16:1-ceramides (Cer), d16:1-hexosylceramides (HexCer), and d16:1-C14:0 lactosylceramide. MA treatment further induced a coordinated shift in cellular sphingolipid pools, characterized by a significant increase in total ceramide levels (encompassing both d16- and d18-species) alongside concurrent reductions in total sphingomyelin (SM) contents. At the gene transcriptional level, MA significantly suppressed SPTLC2 mRNA expression while markedly upregulating SMPD2 and SMPD3 mRNA levels. Conclusions: Collectively, these findings position MA as a potent regulator of sphingolipid homeostasis, orchestrating dual pathway modulation: disrupting canonical d18-SL equilibrium through the selective enrichment of N-acyl C14:0-containing SLs, and activating non-canonical d16-SL synthesis. This dual pathway regulation reveals that dietary saturated fatty acids exploit sphingolipid subnetworks to regulate lipid metabolism. The interplay between dietary fatty acids and sphingolipid metabolism still requires deeper exploration. Our findings offer preliminary insights into their roles in regulating both normal and disease-associated lipid metabolism, setting the stage for subsequent mechanistic investigations. Full article

2-Amino-14,16-dimethyloctadecan-3-ol (AOD) is commonly found in foods contaminated with Fusarium avenaceum, particularly cereals or fruits, and is structurally related to Fusarium mycotoxins (fumonisins) and mammalian sphingoid bases, especially 1-deoxysphinganine (m18:0); therefore, it might enter systemic circulation and tissues upon dietary intake. Knowledge about what happens when cells are exposed to AOD is limited, but it has been reported to be cytotoxic and to induce vacuolization in HepG2 cells. We also found that AOD is cytotoxic for HepG2 cells, but even at a concentration where cell viability remained above 85% (5 μM), it altered 24 differentially expressed genes based on RNA sequencing-based transcriptomic profiling. Among these genes, 13 were shared with cells treated with m18:0. These overlapping differentially expressed genes were primarily enriched in activated stress response pathways of cells, including the upregulation of specific genes in the hypoxia-inducible factor 1α (HIF-1α) signaling pathway, such as hexokinase 1 (HK1) and egl-9 family hypoxia-inducible factor 3 (EGLN3), the activation of key components in the p53 signaling pathway, and the induction of cellular senescence-associated transcriptional programs involving serpin family E member 1 (SERPINE1). Transcriptional analysis of genes related to sphingolipid metabolism showed that treatment with AOD increased the mRNA expression of ceramide synthase 4 (CerS4), sphingosine-1-phosphate phosphatase 1 (SGPP1), and UDP-glucosylceramide glucosyltransferase (UGCG), while decreasing the expression of dihydroceramide desaturase 1 (DEGS1) and fatty acid desaturase 3 (FADS3), a pattern of gene expression changes that mirrored the alterations observed with m18:0 treatment. Lipidomic analyses revealed that AOD significantly perturbed the sphingolipid composition of HepG2 cells, specifically increasing hexosylceramide content while decreasing ceramide and sphingomyelin levels. Moreover, AOD was found to undergo intracellular metabolism to N-acyl-AODs, perhaps by ceramide synthase(s), since this acylation was inhibited by fumonisin B1 (FB1). These findings demonstrate that AOD or possibly its N-acyl metabolites can alter cellular sphingolipid metabolism and affect the expression of genes involved in cell stress. These new insights call for more studies of the impact of this food contaminant on cells and the implications for human health. Full article

Sphingolipids (SLs) are a class of bioactive lipids characterized by sphingoid bases (SBs) as their backbone structure. These molecules exhibit distinct cellular functions, including cell growth, apoptosis, senescence, migration, and inflammatory responses, by interacting with esterases, amidases, kinases, phosphatases, and membrane receptors. These interactions result in a highly interconnected network of enzymes and pathways, known as the sphingolipidome. Dysregulation within this network is implicated in the onset and progression of cardiovascular diseases, metabolic disorders, neurodegenerative disorders, autoimmune diseases, and various cancers. This review highlights the pharmacologically significant sphingoid-based medicinal agents in preclinical and clinical studies. These include myriocin, fingolimod, fenretinide, safingol, spisulosine (ES-285), jaspine B, D-e-MAPP, B13, and α-galactosylceramide. It covers enantioselective syntheses, drug development efforts, and advances in molecular modeling to facilitate an understanding of the binding interactions of these compounds with their biological targets. This review provides a comprehensive evaluation of chiral pool synthetic strategies, translational studies, and the pharmacological relevance of sphingolipid-based drug candidates, offering a pathway for future research in sphingolipid-based therapeutic development. Full article

Dihydroceramide (dhCer) was previously considered an inactive precursor of ceramide, a well-known sphingoid base involved in regulating apoptosis and cell death. However, recent studies have shown that dhCer plays a crucial role in various important cellular responses. In this review, we summarize the latest findings on the biological functions of dhCer and the enzymes involved in its biosynthesis. We specifically focus on the emerging evidence implicating dhCer in cancer, as well as its role in regulating key processes such as cell cycle arrest, autophagy, apoptosis, ER stress, and oxidative stress. Furthermore, we discuss bioactive compounds that can modulate dhCer levels in cancer cells, highlighting their potential therapeutic applications in counteracting cancer progression. This review emphasizes the growing recognition of dhCer as a bioactive sphingolipid metabolite with significant potential for cancer therapy. Full article

Sphingolipidomic mass spectrometry has provided valuable information—and surprises—about sphingolipid structures, metabolism, and functions in normal biological processes and disease. Nonetheless, many noteworthy compounds are not routinely determined, such as the following: most of the sphingoid bases that mammals biosynthesize de novo other than sphingosine (and sometimes sphinganine) or acquire from exogenous sources; infrequently considered metabolites of sphingoid bases, such as N-(methyl)_n-derivatives; “ceramides” other than the most common N-acylsphingosines; and complex sphingolipids other than sphingomyelins and simple glycosphingolipids, including glucosyl- and galactosylceramides, which are usually reported as “monohexosylceramides”. These and other subspecies are discussed, as well as some of the circumstances when they are likely to be seen (or present and missed) due to experimental conditions that can influence sphingolipid metabolism, uptake from the diet or from the microbiome, or as artifacts produced during extraction and analysis. If these compounds and factors are kept in mind during the design and interpretation of lipidomic studies, investigators are likely to be surprised by how often they appear and thereby advance knowledge about them. Full article

Complex sphingolipids are components of eukaryotic biomembranes and are involved in various physiological functions. In addition, their synthetic intermediates and metabolites, such as ceramide, sphingoid long-chain base, and sphingoid long-chain base 1-phosphate, play important roles as signaling molecules that regulate intracellular signal transduction systems. Complex sphingolipids have a large number of structural variations, and this structural diversity is considered an important molecular basis for their various physiological functions. The budding yeast Saccharomyces cerevisiae has simpler structural variations in complex sphingolipids compared to mammals and is, therefore, a useful model organism for elucidating the physiological significance of this structural diversity. In this review, we focus on the structure and function of complex sphingolipids in S. cerevisiae and summarize the response mechanisms of S. cerevisiae to metabolic abnormalities in complex sphingolipids. Full article

Marine sponges represent a good source of natural metabolites for biotechnological applications in the pharmacological, cosmeceutical, and nutraceutical fields. In the present work, we analyzed the biotechnological potential of the alien species Haliclona (Halichoclona) vansoesti de Weerdt, de Kluijver & Gomez, 1999, previously collected in the Mediterranean Sea (Faro Lake, Sicily). The bioactivity and chemical content of this species has never been investigated, and information in the literature on its Caribbean counterpart is scarce. We show that an enriched extract of H. vansoesti induced cell death in human melanoma cells with an IC₅₀ value of 36.36 µg mL⁻¹, by (i) triggering a pro-inflammatory response, (ii) activating extrinsic apoptosis mediated by tumor necrosis factor receptors triggering the mitochondrial apoptosis via the involvement of Bcl-2 proteins and caspase 9, and (iii) inducing a significant reduction in several proteins promoting human angiogenesis. Through orthogonal SPE fractionations, we identified two active sphingoid-based lipid classes, also characterized by nuclear magnetic resonance and mass spectrometry, as the main components of two active fractions. Overall, our findings provide the first evaluation of the anti-cancer potential of polar lipids isolated from the marine sponge H. (Halichoclona) vansoesti, which may lead to new lead compounds with biotechnological applications in the pharmaceutical field. Full article

While much has been learned about sphingolipids, originally named for their sphinx-like enigmatic properties, there are still many unanswered questions about the possible effect(s) of the composition of ceramide on the synthesis and/or behavior of a glycosphingolipid (GSL). Over time, studies of their ceramide component, the sphingoid base containing the lipid moiety of GSLs, were frequently distinct from those performed to ascertain the roles of the carbohydrate moieties. Due to the number of classes of GSLs that can be derived from ceramide, this review focuses on the possible role(s) of ceramide in the synthesis/function of just one GSL class, derived from glucosylceramide (Glc-Cer), namely sialylated ganglio derivatives, initially characterized and named gangliosides (GGs) due to their presence in ganglion cells. While much is known about their synthesis and function, much is still being learned. For example, it is only within the last 15–20 years or so that the mechanism by which the fatty acyl component of ceramide affected its transport to different sites in the Golgi, where it is used for the synthesis of Glu- or galactosyl-Cer (Gal-Cer) and more complex GSLs, was defined. Still to be fully addressed are questions such as (1) whether ceramide composition affects the transport of partially glycosylated GSLs to sites where their carbohydrate chain can be elongated or affects the activity of glycosyl transferases catalyzing that elongation; (2) what controls the differences seen in the ceramide composition of GGs that have identical carbohydrate compositions but vary in that of their ceramide and vice versa; (3) how alterations in ceramide composition affect the function of membrane GGs; and (4) how this knowledge might be applied to the development of therapies for treating diseases that correlate with abnormal expression of GGs. The availability of an updatable data bank of complete structures for individual classes of GSLs found in normal tissues as well as those associated with disease would facilitate research in this area. Full article

Sphingosine-1-phosphate lyase (SPL) resides at the endpoint of the sphingolipid metabolic pathway, catalyzing the irreversible breakdown of sphingosine-1-phosphate. Depletion of SPL precipitates compromised muscle morphology and function; nevertheless, the precise mechanistic underpinnings remain elusive. Here, we elucidate a model of SPL functional deficiency in Caenorhabditis elegans using spl-1 RNA interference. Within these SPL-deficient nematodes, we observed diminished motility and perturbed muscle fiber organization, correlated with the accumulation of sphingoid bases, their phosphorylated forms, and ceramides (collectively referred to as the “sphingolipid rheostat”). The disturbance in mitochondrial morphology was also notable, as SPL functional loss resulted in heightened levels of reactive oxygen species. Remarkably, the administration of the antioxidant N-acetylcysteine (NAC) ameliorates locomotor impairment and rectifies muscle fiber disarray, underscoring its therapeutic promise for ceramide-accumulation-related muscle disorders. Our findings emphasize the pivotal role of SPL in preserving muscle integrity and advocate for exploring antioxidant interventions, such as NAC supplementation, as prospective therapeutic strategies for addressing muscle function decline associated with sphingolipid/ceramide metabolism disruption. Full article

Pancreatic cancer is characterized by its high mortality rate and limited treatment options, often driven by oncogenic RAS mutations. In this study, we investigated the metabolomic profiles of pancreatic cancer cells based on their KRAS genetic status. Utilizing both KRAS-wildtype BxPC3 and KRAS-mutant PANC1 cell lines, we identified 195 metabolites differentially altered by KRAS status through untargeted metabolomics. Principal component analysis and hierarchical condition trees revealed distinct separation between KRAS-wildtype and KRAS-mutant cells. Metabolite set enrichment analysis highlighted significant pathways such as homocysteine degradation and taurine and hypotaurine metabolism. Additionally, lipid enrichment analysis identified pathways including fatty acyl glycosides and sphingoid bases. Mapping of identified metabolites to KEGG pathways identified nine significant metabolic pathways associated with KRAS status, indicating diverse metabolic alterations in pancreatic cancer cells. Furthermore, we explored the impact of TRPML1 inhibition on the metabolomic profile of KRAS-mutant pancreatic cancer cells. TRPML1 inhibition using ML-SI1 significantly altered the metabolomic profile, leading to distinct separation between vehicle-treated and ML-SI1-treated PANC1 cells. Metabolite set enrichment analysis revealed enriched pathways such as arginine and proline metabolism, and mapping to KEGG pathways identified 17 significant metabolic pathways associated with TRPML1 inhibition. Interestingly, some metabolites identified in PANC1 compared to BxPC3 were oppositely regulated by TRPML1 inhibition, suggesting their potential as biomarkers for KRAS-mutant cancer cells. Overall, our findings shed light on the distinct metabolite changes induced by both KRAS status and TRPML1 inhibition in pancreatic cancer cells, providing insights into potential therapeutic targets and biomarkers for this deadly disease. Full article

Abnormalities of sphingolipid metabolism play an important role in diabetes. We compared sphingolipid levels in plasma and in isolated lipoproteins between healthy control subjects and two groups of patients, one with chronic kidney disease without diabetes (ND-CKD), and the other with type 2 diabetes and macroalbuminuria (D-MA). Ceramides, sphingomyelins, and sphingoid bases and their phosphates in LDL were higher in ND-CKD and in D-MA patients compared to controls. However, ceramides and sphingoid bases in HDL2 and HDL3 were lower in ND-CKD and in D-MA patients than in controls. Sphingomyelins in HDL2 and HDL3 were lower in D-MA patients than in controls but were normal in ND-CKD patients. Compared to controls, lactosylceramides in LDL and VLDL were higher in ND-CKD patients but not in D-MA patients. However, lactosylceramides in HDL2 and HDL3 were lower in both ND-CKD and D-MA patients than in controls. Plasma hexosylceramides in ND-CKD patients were increased and sphingoid bases decreased in both ND-CKD and D-MA patients. However, hexosylceramides in LDL, HDL2, and HDL3 were higher in ND-CKD patients than in controls. In D-MA patients, only C16:0 hexosylceramide in LDL was higher than in controls. The data suggest that sphingolipid measurement in lipoproteins, rather than in whole plasma, is crucial to decipher the role of sphingolipids in kidney disease. Full article

This cross-sectional study aimed to investigate differences in skin surface lipids (SSL) and explore related metabolic pathways among females of different ages in Henan Province. Ultra-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF-MS) was used to determine the lipid composition of the skin surface of 58 female volunteers who were divided into three age groups. Statistical analysis was performed using Progenesis QI, Ezinfo, and MetaboAnalyst. Multivariate and enrichment analysis were used to identify the different SSL among the groups. A total of 530 lipid entities were identified and classified into eight classes. Among these, 63 lipids were significantly different between the groups. Lower levels of glycerolipids (GLs) and sphingolipids (SPs) were observed in the middle-aged group, while higher levels of GLs were found in the elder group. GLs belonged to the largest and statistically significant enrichment of lipid metabolic pathways, and the lipid individuals enriched to the sphingoid bases metabolism were the most and statistically significant. These findings suggest that there are differences in hand SSL among females of different ages, which may be related to GLs and sphingoid bases metabolism. Full article

Both bioactive sphingolipids and Sigma-1 receptor (S1R) chaperones occur ubiquitously in mammalian cell membranes. Endogenous compounds that regulate the S1R are important for controlling S1R responses to cellular stress. Herein, we interrogated the S1R in intact Retinal Pigment Epithelial cells (ARPE-19) with the bioactive sphingoid base, sphingosine (SPH), or the pain-provoking dimethylated SPH derivative, N,N’-dimethylsphingosine (DMS). As informed by a modified native gel approach, the basal and antagonist (BD-1047)-stabilized S1R oligomers dissociated to protomeric forms in the presence of SPH or DMS (PRE-084 as control). We, thus, posited that SPH and DMS are endogenous S1R agonists. Consistently, in silico docking of SPH and DMS to the S1R protomer showed strong associations with Asp126 and Glu172 in the cupin beta barrel and extensive van der Waals interactions of the C18 alkyl chains with the binding site including residues in helices 4 and 5. Mean docking free energies were 8.73–8.93 kcal/mol for SPH and 8.56–8.15 kcal/mol for DMS, and calculated binding constants were ~40 nM for SPH and ~120 nM for DMS. We hypothesize that SPH, DMS, and similar sphingoid bases access the S1R beta barrel via a membrane bilayer pathway. We further propose that the enzymatic control of ceramide concentrations in intracellular membranes as the primary sources of SPH dictates availability of endogenous SPH and DMS to the S1R and the subsequent control of S1R activity within the same cell and/or in cellular environments. Full article

Sphingolipids are exceptionally diverse, comprising hundreds of unique species. The bulk of circulating sphingolipids are synthesized in the liver, thereby plasma sphingolipid profiles represent reliable surrogates of hepatic sphingolipid metabolism and content. As changes in plasma sphingolipid content have been associated to exposure to drugs inducing hepatotoxicity both in vitro and in rodents, in the present study the translatability of the preclinical data was assessed by analyzing the plasma of patients with suspected drug-induced liver injury (DILI) and control subjects. DILI patients, whether intrinsic or idiosyncratic cases, had no alterations in total sphingoid base levels and profile composition compared to controls, whereby cardiovascular disease (CVD) was a confounding factor. Upon exclusion of CVD individuals, elevation of 1-deoxysphingosine (1-deoxySO) in the DILI group emerged. Notably, 1-deoxySO values did not correlate with ALT values. While 1-deoxySO was elevated in all DILI cases, only intrinsic DILI cases concomitantly displayed reduction of select shorter chain sphingoid bases. Significant perturbation of the sphingolipid metabolism observed in this small exploratory clinical study is discussed and put into context, in the consideration that sphingolipids might contribute to the onset and progression of DILI, and that circulating sphingoid bases may function as mechanistic markers to study DILI pathophysiology. Full article

Sphingolipids are key molecules in inflammation and defense against pathogens. Their role in dectin-1/TLR2-mediated responses is, however, poorly understood. This study investigated the sphingolipidome in the peritoneal fluid, peritoneal cells, plasma, and spleens of mice after intraperitoneal injection of 0.1 mg zymosan/mouse or PBS as a control. Samples were collected at 2, 4, 8, and 16 h post-injection, using a total of 36 mice. Flow cytometry analysis of peritoneal cells and measurement of IL-6, IL-1β, and TNF-α levels in the peritoneal lavages confirmed zymosan-induced peritonitis. The concentrations of sphingoid bases, dihydroceramides, ceramides, dihydrosphingomyelins, sphingomyelins, monohexosylceramides, and lactosylceramides were increased after zymosan administration, and the effects varied with the time and the matrix measured. The greatest changes occurred in peritoneal cells, followed by peritoneal fluid, at 8 h and 4 h post-injection, respectively. Analysis of the sphingolipidome suggests that zymosan increased the de novo synthesis of sphingolipids without change in the C14–C18:C20–C26 ceramide ratio. At 16 h post-injection, glycosylceramides remained higher in treated than in control mice. A minor effect of zymosan was observed in plasma, whereas sphinganine, dihydrosphingomyelins, and monohexosylceramides were significantly increased in the spleen 16 h post-injection. The consequences of the observed changes in the sphingolipidome remain to be established. Full article