Circular Network of Coregulated Sphingolipids Dictates Chronic Hypoxia Damage in Patients With Tetralogy of Fallot

Background: Tetralogy of Fallot (TOF) is the most common cyanotic heart disease. However, the association of cardiac metabolic reprogramming changes and underlying molecular mechanisms in TOF-related chronic myocardial hypoxia damage are still unclear.Methods: In this study, we combined microarray transcriptomics analysis with liquid chromatography tandem-mass spectrometry (LC–MS/MS) spectrum metabolomics analysis to establish the metabolic reprogramming that occurs in response to chronic hypoxia damage. Two Gene Expression Omnibus (GEO) datasets, GSE132176 and GSE141955, were downloaded to analyze the metabolic pathway in TOF. Then, a metabolomics analysis of the clinical samples (right atrial tissue and plasma) was performed. Additionally, an association analysis between differential metabolites and clinical phenotypes was performed. Next, four key genes related to sphingomyelin metabolism were screened and their expression was validated by real-time quantitative PCR (QT-PCR).Results: The gene set enrichment analysis (GSEA) showed that sphingolipid metabolism was downregulated in TOF and the metabolomics analysis showed that multiple sphingolipids were dysregulated. Additionally, genes related to sphingomyelin metabolism were identified. We found that four core genes, UDP-Glucose Ceramide Glucosyltransferase (UGCG), Sphingosine-1-Phosphate Phosphatase 2 (SGPP2), Fatty Acid 2-Hydroxylase (FA2H), and Sphingosine-1-Phosphate Phosphatase 1 (SGPP1), were downregulated in TOF.Conclusion: Sphingolipid metabolism was downregulated in TOF; however, the detailed mechanism needs further investigation.

Candidate Gene and MicroRNA Biomarkers of Metastatic Renal Cell Carcinoma (MRCC) Response to Sunitinib

Backgrounds: The incidence of renal cancer is relatively insidious, and some patients have been metastatic renal cancer at the initial visit. Sunitinib is the first-line systemic therapy for patients with metastatic renal cell carcinoma, however, there is scant analysis of its effect on genes and microRNAs.Methods: In this study, 8 differentially expressed microRNAs and 112 differentially expressed genes were designated by analyzing mRNA and microRNA data sets and weighted correlation network analysis (WGCNA).Results: NIPSNAP1 gene showed the most co-expression with other genes. Through the intersection of the microRNA target gene with our differentially expressed genes, we got 26 genes. KEGG and GO analysis showed that these genes were predominantly concentrated in Pathways in cancer, Sphingolipid metabolism and Glycosaminoglycan degradation. After we set the 26 genes and gene of WGCNA do intersection, received six genes, respectively is NIPSNAP1, SDC4, TBC1D9, NEU1, STK40 and PLAUR. Conclusion: Through subsequent cell, molecular and flow cytometry experiments, we found the PLAUR would play a crucial role in renal cell carcinoma (RCC) resistant to sunitinib, which will be available for new ideas to forecast sunitinib resistance and reverse sunitinib resistance.

The sphingosine 1-phosphate receptor 2/4 antagonist JTE-013 elicits off-target effects on sphingolipid metabolism

Sphingosine 1-phosphate (S1P) is a signaling lipid that has broad roles, working either intracellularly through various protein targets, or extracellularly via a family of five G-protein coupled receptors. Agents that selectively and specifically target each of the S1P receptors have been sought as both biological tools and potential therapeutics. JTE-013, a small molecule antagonist of S1P receptors 2 and 4 (S1P2 and S1P4) has been widely used in defining the roles of these receptors in various biological processes. Indeed, our previous studies showed that JTE-013 had anti-acute myeloid leukaemia (AML) activity, supporting a role for S1P2 in the biology and therapeutic targeting of AML. Here we examined this further and describe lipidomic analysis of AML cells that revealed JTE-013 caused alterations in sphingolipid metabolism, increasing cellular ceramides, dihydroceramides, sphingosine and dihydrosphingosine. Further examination of the mechanisms behind these observations showed that JTE-013, at concentrations frequently used in the literature to target S1P2/4, inhibits several sphingolipid metabolic enzymes, including dihydroceramide desaturase 1 and both sphingosine kinases. Collectively, these findings demonstrate that JTE-013 can have broad off-target effects on sphingolipid metabolism and highlight that caution must be employed in interpreting the use of this reagent in defining the roles of S1P2/4.

Implication of Sphingolipid Metabolism Gene Dysregulation and Cardiac Sphingosine-1-Phosphate Accumulation in Heart Failure

Disturbances in sphingolipid metabolism lead to biological function dysregulation in many diseases, but it has not been described in heart failure (HF). Sphingosine-1-phosphate (S1P) levels have not ever been measured in the myocardium. Therefore, we analyze the gene dysregulation of human cardiac tissue by mRNA-seq (n = 36) and ncRNA-seq (n = 50). We observed most major changes in the expression of genes belonging to de novo and salvage pathways, and the tight gene regulation by their miRNAs is largely dysregulated in HF. We verified using ELISA (n = 41) that ceramide and S1P accumulate in HF cardiac tissue, with an increase in the ceramide/S1P ratio of 57% in HF. Additionally, changes in left ventricular mass and diameters are directly related to CERS1 expression and inversely related to S1P levels. Altogether, we define changes in the main components of the sphingolipid metabolism pathways in HF, mainly de novo and salvage, which lead to an increase in ceramide and S1P in cardiac tissue, as well as an increase in the ceramide/S1P ratio in HF patients. Therapeutic gene modulation focused on restoring ceramide levels or reversing the ceramide/S1P ratio could be a potential therapy to be explored for HF patients.

The Sphingolipid Asset Is Altered in the Nigrostriatal System of Mice Models of Parkinson’s Disease

Parkinson’s disease (PD) is a neurodegenerative disease incurable due to late diagnosis and treatment. Therefore, one of the priorities of neurology is to study the mechanisms of PD pathogenesis at the preclinical and early clinical stages. Given the important role of sphingolipids in the pathogenesis of neurodegenerative diseases, we aimed to analyze the gene expression of key sphingolipid metabolism enzymes (ASAH1, ASAH2, CERS1, CERS3, CERS5, GBA1, SMPD1, SMPD2, UGCG) and the content of 32 sphingolipids (subspecies of ceramides, sphingomyelins, monohexosylceramides and sphinganine, sphingosine, and sphingosine-1-phosphate) in the nigrostriatal system in 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse models of the preclinical and clinical stages of PD. It has been shown that in PD models, the expression of five of the nine studied genes (CERS1, CERS5, ASAH1, ASAH2, and GBA1) increases but only in the substantia nigra (SN) containing dopaminergic cell bodies. Changes in the expression of enzyme genes were accompanied by an increase in the content of 7 of the 32 studied sphingolipids. Such findings suggest these genes as attractive candidates for diagnostic purposes for preclinical and clinical stages of PD.

Implication of Ceramide Kinase/C1P in Cancer Development and Progression

Cancer cells rewire their metabolic programs to favor biological processes that promote cell survival, proliferation, and dissemination. Among this relevant reprogramming, sphingolipid metabolism provides metabolites that can favor or oppose these hallmarks of cancer. The sphingolipid ceramide 1-phosphate (C1P) and the enzyme responsible for its biosynthesis, ceramide kinase (CERK), are well established regulators of cell growth and survival in normal, as well as malignant cells through stress-regulated signaling pathways. This metabolite also promotes cell survival, which has been associated with the feedback regulation of other antitumoral sphingolipids or second messengers. C1P also regulates cancer cell invasion and migration of different types of cancer, including lung, breast, pancreas, prostate, or leukemia cells. More recently, CERK and C1P have been implicated in the control of inflammatory responses. The present review provides an updated view on the important role of CERK/C1P in the regulation of cancer cell growth, survival, and dissemination.

Metabolic Profiling Of Obesity With And Without The Metabolic Syndrome – A Multi-Sample Evaluation

Context There is a dispute whether obesity without major metabolic derangements may represent a benign condition or not. Objective We aimed to compare the plasma metabolome in obese subjects without the metabolic syndrome (MetS) to normal-weight subjects without MetS, as well as to obese subjects with MetS. Design Cross-sectional. Setting Two academic centers in Sweden. Participants Three population-based samples (EpiHealth, n=2342, SCAPIS-Uppsala, n=4985 and SCAPIS-Malmö, n=3978) in which individuals were divided into groups according to their BMI and presence/absence of MetS (NCEP/consensus criteria). Intervention None Main Outcome Measure 791 annotated endogenous metabolites measured by ultra-performance liquid chromatography tandem mass spectrometry Results We observed major differences in metabolite profiles (427 metabolites) between obese (BMI ≥ 30 kg/m 2) and normal-weight (BMI < 25 kg/m 2) subjects without MetS after adjustment for major life-style factors. Pathway enrichment analysis highlighted branch-chained and aromatic amino acid synthesis/metabolism, aminoacyl-tRNA biosynthesis and sphingolipid metabolism. The same pathways, and similar metabolites, were also highlighted when obese subjects with and without MetS were compared despite adjustment for BMI and waist circumference, or when the metabolites were related to BMI and number of MetS components in a continuous fashion. Similar metabolites and pathways were also related to insulin sensitivity (Matsuda index) in a separate study (POEM, n=501). Conclusion Our data suggest a graded derangement of the circulating metabolite profile from lean to obese to the metabolic syndrome, in particular for metabolites involved in amino acid synthesis/metabolism and sphingolipid metabolism. Insulin resistance is a plausible mediator of this gradual metabolic deterioration.

Loss of E-Cadherin Leads to Druggable Vulnerabilities in Sphingolipid Metabolism and Vesicle Trafficking

Germline inactivating variants of CDH1 are causative of hereditary diffuse gastric cancer (HDGC), a cancer syndrome characterzsed by an increased risk of both diffuse gastric cancer and lobular breast cancer. Because loss of function mutations are difficult to target therapeutically, we have taken a synthetic lethal approach to identify targetable vulnerabilities in CDH1-null cells. We have previously observed that CDH1-null MCF10A cells exhibit a reduced rate of endocytosis relative to wildtype MCF10A cells. To determine whether this deficiency is associated with wider vulnerabilities in vesicle trafficking, we screened isogenic MCF10A cell lines with known inhibitors of autophagy, endocytosis, and sphingolipid metabolism. Relative to wildtype MCF10A cells, CDH1−/− MCF10A cells showed significantly greater sensitivity to several drugs targeting these processes, including the autophagy inhibitor chloroquine, the endocytosis inhibitors chlorpromazine and PP1, and the sphingosine kinase 1 inhibitor PF-543. Synthetic lethality was confirmed in both gastric and mammary organoid models of CDH1 loss, derived from CD44-Cre/Cdh1fl/fl/tdTomato mice. Collectively, these results suggest that both sphingolipid metabolism and vesicle trafficking represent previously unrecognised druggable vulnerabilities in CDH1-null cells and may lead to the development of new therapies for HDGC.

Isoform-Dependent Effects of Apolipoprotein E on Sphingolipid Metabolism in Neural Cells

Background: Sphingosine 1-phosphate (S1P) and ceramides have been implicated in the development of Alzheimer’s disease. Apolipoprotein E (ApoE) isoforms are also involved in the development of Alzheimer’s disease. Objective: We aimed at elucidating the potential association of the ApoE isoforms with sphingolipid metabolism in the central nervous system. Methods: We investigated the modulations of apolipoprotein M (apoM), a carrier of S1P, S1P, and ceramides in Apoeshl mice, which spontaneously lack apoE, and U251 cells and SH-SY5Y cells infected with adenovirus vectors encoding for apoE2, apoE3, and apoE4. Results: In the brains of Apoeshl mice, the levels of apoM were lower, while those of ceramides were higher. In U251 cells, cellular apoM and S1P levels were the highest in the cells overexpressing apoE2 among the apoE isoforms. The cellular and medium contents of ceramides decreased in the order of the cells overexpressing apoE3 > apoE2 and increased in the cells overexpressing apoE4. In SH-SY5Y cells, apoM mRNA and medium S1P levels were also the highest in the cells overexpressing apoE2. The cellular contents of ceramides decreased in the order of the cells overexpressing apoE3 > apoE2 = apoE4 and those in medium decreased in the order of the cells overexpressing apoE3 > apoE2, while increased in the cells overexpressing apoE4. Conclusion: The modulation of apoM and S1P might partly explain the protective effects of apoE2 against Alzheimer’s disease, and the modulation of ceramides might be one of the mechanisms explaining the association of apoE4 with the development of Alzheimer’s disease.