Aging stress and ceramide dependent RNA sequencing expression profiling depends on ceramide synthase 6
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ABSTRACT:
ORGANISM(S): Mus musculus
PROVIDER: GSE148498 | GEO | 2021/01/01
REPOSITORIES: GEO
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Project description:Growing evidence correlated changes in bioactive sphingolipids, particularly sphingosine-1-phosphate (S1P) and ceramides, with coronary artery diseases. Furthermore, specific plasma ceramide species can predict major cardiovascular events. Dysfunction of the endothelium lining lesion-prone areas plays a pivotal role in the initiation and progression of atherosclerosis. Yet, how sphingolipid metabolism and signaling change and contribute to endothelial dysfunction and atherosclerosis remain poorly understood. By using a mouse model of coronary atherosclerosis, we demonstrated that hemodynamic stress induces an early metabolic rewiring of endothelial sphingolipid de novo biosynthesis favoring S1P signaling over ceramide as protective response. Furthermore, our data are paradigm shift from the current believe that ceramide accrual contributes to endothelial dysfunction. The de novo biosynthesis of sphingolipids is commenced by serine palmitoyltransferase (SPT), and is downregulated by NOGO-B, an ER membrane protein. We showed that Nogo-B is upregulated by hemodynamic stress in myocardial endothelial cells (EC) of ApoE-/- mice and is expressed in the endothelium lining coronary lesions in mice and human. We demonstrated that mice lacking Nogo-B specifically in EC (Nogo-A/BECKOApoE-/-) were resistant to coronary atherosclerosis development and progression, and mortality. Fibrous cap thickness was significantly increased in Nogo-A/BECKOApoE-/- mice and correlated with reduced necrotic core and macrophage infiltration. Mechanistically, the deletion of Nogo-B in EC sustained the rewiring of sphingolipid metabolism towards S1P, imparting an atheroprotective transcriptional signature that refrain coronary atherogenesis and its progression. These findings also set forth the foundation for sphingolipid-based therapeutics to reduce the treat this condition.
2024-02-12 | GSE254426 | GEO
Project description:The cleavage of sphingoid base phosphates by sphingosine-1-phosphate (S1P) lyase to produce phosphoethanolamine and a fatty aldehyde is the final degradative step in the sphingolipid metabolic pathway. We have studied mice with an inactive S1P lyase gene and have found that, in addition to the expected increase of sphingoid base phosphates, other sphingolipids (including sphingosine, ceramide, and sphingomyelin) were substantially elevated in the serum and /or liver of these mice. This latter increase is consistent with a reutilization of the sphingosine backbone for sphingolipid synthesis due to its inability to exit the sphingolipid metabolic pathway. Furthermore, the S1P lyase deficiency resulted in changes in the levels of serum and liver lipids not directly within the sphingolipid pathway, including phospholipids, triacyglycerol, diacylglycerol, and cholesterol. Even though lipids in serum and lipid storage were elevated in liver, adiposity was reduced in the S1P lyase-deficient mice. Microarray analysis of lipid metabolism genes in liver showed that the S1P lyase deficiency caused widespread changes in their expression pattern. These results demonstrate that S1P lyase is a key regulator of the levels of multiple sphingolipid substrates and reveal functional links between the sphingolipid metabolic pathway and other lipid metabolic pathways that may be mediated by shared lipid substrates and changes in gene expression programs. The disturbance of lipid homeostasis by altered sphingolipid levels may be relevant to metabolic diseases. Experiment Overall Design: RNA samples from liver for three sphingosine-1-phosphate lyase knock-out and three WT mice.
2010-02-05 | E-GEOD-18745 | biostudies-arrayexpress
Project description:Aging stress and ceramide dependent RNA sequencing expression profiling depends on ceramide synthase 6
| PRJNA624654 | ENA
Project description:Sphingolipids are structural membrane components that also function in cellular stress responses. The serine palmitoyl-transferase (SPT) catalyzes the rate limiting step in sphingolipid biogenesis. Its activity is tightly regulated through multiple bind-ing partners, including Tsc3, Orm proteins, ceramides, and the phosphatidylinositol-4-phosphate (PI4P) phosphatase Sac1. The structural organization and regulatory mechanisms of this complex are not yet understood. Here, we report the high-resolution cryo-EM structures of the yeast SPT in complex with Tsc3 and Orm1 (SPOT) as dimers and monomers and a monomeric complex further carrying Sac1 (SPOTS). In all complexes, the tight interaction of the down-stream metabolite ceramide and Orm1 reveals the ceramide dependent inhibition. Additionally, observation of ceramide and ergosterol binding suggests a co-regulation of sphingolipid biogenesis and sterol metabolism within the SPOTS com-plex.
2023-10-24 | PXD044586 | Pride
Project description:Alcohol’s impairment of both hepatic lipid metabolism and insulin resistance (IR) are key drivers of alcoholic steatosis, the initial stage of alcoholic liver disease (ALD). Pharmacologic reduction of lipotoxic ceramide prevents alcoholic steatosis and glucose intolerance in mice, but potential off-target effects limit its strategic utility. Here, we employed a hepatic-specific acid-ceramidase (ASAH) overexpression model to reduce hepatic ceramides in a Lieber-DeCarli model of experimental alcoholic steatosis. We examined effects of alcohol on hepatic lipid metabolism, body composition, energy homeostasis and insulin sensitivity as measured by hyperinsulinemic-euglycemic clamp. Our results demonstrate that hepatic ceramide reduction ameliorates the effects of alcohol on hepatic lipid droplet accumulation by promoting VLDL secretion and lipophagy, the latter of which involves ceramide cross-talk between the lysosomal and lipid droplet compartments. We additionally demonstrate that hepatic ceramide reduction prevents alcohol’s inhibition of hepatic insulin signaling. These effects on the liver are associated with a reduction in oxidative stress markers and are relevant to humans, as we observe peri-lipid droplet ASAH expression in human ALD. Together, our results suggest a potential role for hepatic ceramide inhibition in preventing ALD.
2020-07-08 | GSE139015 | GEO
Project description:The cleavage of sphingoid base phosphates by sphingosine-1-phosphate (S1P) lyase to produce phosphoethanolamine and a fatty aldehyde is the final degradative step in the sphingolipid metabolic pathway. We have studied mice with an inactive S1P lyase gene and have found that, in addition to the expected increase of sphingoid base phosphates, other sphingolipids (including sphingosine, ceramide, and sphingomyelin) were substantially elevated in the serum and /or liver of these mice. This latter increase is consistent with a reutilization of the sphingosine backbone for sphingolipid synthesis due to its inability to exit the sphingolipid metabolic pathway. Furthermore, the S1P lyase deficiency resulted in changes in the levels of serum and liver lipids not directly within the sphingolipid pathway, including phospholipids, triacyglycerol, diacylglycerol, and cholesterol. Even though lipids in serum and lipid storage were elevated in liver, adiposity was reduced in the S1P lyase-deficient mice. Microarray analysis of lipid metabolism genes in liver showed that the S1P lyase deficiency caused widespread changes in their expression pattern. These results demonstrate that S1P lyase is a key regulator of the levels of multiple sphingolipid substrates and reveal functional links between the sphingolipid metabolic pathway and other lipid metabolic pathways that may be mediated by shared lipid substrates and changes in gene expression programs. The disturbance of lipid homeostasis by altered sphingolipid levels may be relevant to metabolic diseases.
2010-01-28 | GSE18745 | GEO
Project description:Ceramides are important participants of signal transduction, regulating fundamental cellular processes. Here we report the mechanism for activation of p53 tumor suppressor by C16-ceramide. C16-ceramide tightly binds within the p53 DNA binding domain (Kd ~ 60 nM), in close vicinity to the Box V motif. This interaction is highly selective towards the ceramide acyl chain length with its C10 atom being proximal to Ser240 and Ser241. Ceramide binding stabilizes p53 and disrupts its complex with E3 ligase MDM2 leading to the p53 accumulation, nuclear translocation and activation of the downstream targets. This is a novel physiological mechanism of p53 activation, which is fundamentally different from the canonical p53 regulation through protein-protein interactions or post-translational modifications. The discovered mechanism is triggered by serum or folate deprivation implicating it in the cellular response to nutrient/metabolic stress. Our study establishes C16-ceramide as the first natural small molecule activating p53 through the direct binding.
2018-10-16 | PXD010783 | Pride
Project description:Mutations in glucocerebrosidase (GBA) are the most prevalent genetic risk factor for Lewy body disorders (LBD) – collectively Parkinson’s disease, Parkinson’s disease dementia and dementia with Lewy bodies. Despite this genetic association, it remains unclear how GBA mutation contributes to the susceptibility of developing LBD. We investigated relationships between LBD-specific glucocerebrosidase deficits, GBA-related pathways, and α-synuclein levels in post-mortem brain tissue from LBD and controls with and without GBA mutations. Our study shows that LBD brains, regardless of GBA mutations, are characterised by altered sphingolipid metabolism, with prominent changes in ceramide species. Since extracellular vesicles (EV) could be involved in LBD pathogenesis by spreading disease linked lipids and proteins, we investigated EV derived from post-mortem cerebrospinal fluid (CSF) and brain tissue from GBA mutation carriers and non-carriers. EV purified from LBD post-mortem CSF and frontal cortex are heavily loaded with ceramides and neurodegeneration-linked proteins including alpha-synuclein and amyloid precursor protein. Our in vitro studies demonstrate that LBD EV constitute a “pathological package” capable of inducing aggregation of wild type alpha-synuclein, potentially through a combination of alpha-synuclein-ceramide interaction and the presence of pathological forms of alpha-synuclein. Together our findings indicate that abnormalities in ceramide metabolism are a feature of LBD, constituting a promising source of biomarkers. GBA mutation likely accelerates the pathological process occurring in sporadic LBD, probably through endolysosomal deficiency, but does not induce alpha-synucleinopathy since healthy normal GBA mutation carriers without alpha-synuclein pathology occur.
2021-11-02 | PXD026980 | Pride
Project description:The replacement of two consecutive histidine residues by alanine residues in the catalytic center of ceramide synthase 2 in new transgenic mouse mutants (CerS2 H/A) leads to inactivation of catalytic activity and reduces protein level to 60% of the WT level. We show here by qRT-PCR and transcriptome analyses that several transcripts of genes involved in lipid metabolism and cell division are differentially regulated in livers of CerS2 H/A mice. Thus very long chain ceramides produced by CerS2 are required for transcriptional regulation of target genes. The previously described formation of hepatocarcinomas in CerS2 KO mice occurred already in 6‑week-old animals and also originated in the loss of CerS2 catalytic activity. The additional loss of the CerS2 homeodomain in newly generated CerS2 Del mice that almost completely lack CerS2 protein expression mostly corroborated the transcriptional effects of the CerS2 catalytic domain (nevertheless, it appears to have independent effects such as induction of cholangiocarcinomas.
2018-04-19 | GSE102938 | GEO
Project description:Reciprocal interactions between breast cancer cells and the tumor microenvironment are important for cancer progression and metastasis. We report here that the deletion or inhibition of sphingosine kinase 2 (SphK2), which produces sphingosine-1-phosphate (S1P), markedly suppresses syngeneic breast tumor growth and lung metastasis in mice by creating a hostile microenvironment for tumor growth and invasion. SphK2 deficiency decreased S1P and concomitantly increased ceramides, including C16-ceramide, in stromal fibroblasts. Ceramide accumulation suppressed activation of cancer-associated fibroblasts (CAFs) by upregulating stromal p53, which restrained production of tumor-promoting factors to reprogram the tumor microenvironment and restrict breast cancer establishment. Ablation of p53 in SphK2-deficient fibroblasts reversed these effects, enabled CAF activation and promoted tumor growth and invasion. These data uncovered a novel role of SphK2 in regulating non-cell autonomous functions of p53 in stromal fibroblasts and their transition to tumor-promoting CAFs, paving the way for the development of a strategy to target the tumor microenvironment and enhance therapeutic efficacy.
2020-01-01 | GSE136655 | GEO