Development of pheochromocytoma in ceramide synthase 2 null mice

Pheochromocytoma (PCC) and paraganglioma are rare neuroendocrine tumors of the adrenal medulla and sympathetic and parasympathetic paraganglia, for which mutations in ∼15 disease-associated genes have been identified. We now document the role of an additional gene in mice, the ceramide synthase 2 (CerS2) gene. CerS2, one of six mammalian CerS, synthesizes ceramides with very-long (C22–C24) chains. The CerS2 null mouse has been well characterized and displays lesions in several organs including the liver, lung and the brain. We now demonstrate that changes in the sphingolipid acyl chain profile of the adrenal gland lead to the generation of adrenal medullary tumors. Histological analyses revealed that about half of the CerS2 null mice developed PCC by ∼13 months, and the rest showed signs of medullary hyperplasia. Norepinephrine and normetanephrine levels in the urine were elevated at 7 months of age consistent with the morphological abnormalities found at later ages. Accumulation of ceroid in the X-zone was observed as early as 2 months of age and as a consequence, older mice displayed elevated levels of lysosomal cathepsins, reduced proteasome activity and reduced activity of mitochondrial complex IV by 6 months of age. Together, these findings implicate an additional pathway that can lead to PCC formation, which involves alterations in the sphingolipid acyl chain length. Analysis of the role of sphingolipids in PCC may lead to further understanding of the mechanism by which PCC develops, and might implicate the sphingolipid pathway as a possible novel therapeutic target for this rare tumor.

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Inactivation of Ceramide Synthase 6 in Mice Results in an Altered Sphingolipid Metabolism and Behavioral Abnormalities

Journal of Biological Chemistry ◽

10.1074/jbc.m113.479907 ◽

2013 ◽

Vol 288 (29) ◽

pp. 21433-21447 ◽

Cited By ~ 51

Author(s):

Philipp Ebel ◽

Katharina vom Dorp ◽

Elisabeth Petrasch-Parwez ◽

Armin Zlomuzica ◽

Kiyoka Kinugawa ◽

...

Keyword(s):

Expression Patterns ◽

Acyl Chain ◽

Sphingolipid Metabolism ◽

Ceramide Synthase ◽

Acyl Chain Length ◽

Hind Limbs ◽

Behavioral Abnormalities ◽

Ceramide Content ◽

Ceramide Synthases ◽

The Brain

The N-acyl chain length of ceramides is determined by the specificity of different ceramide synthases (CerS). The CerS family in mammals consists of six members with different substrate specificities and expression patterns. We have generated and characterized a mouse line harboring an enzymatically inactive ceramide synthase 6 (CerS6KO) gene and lacz reporter cDNA coding for β-galactosidase directed by the CerS6 promoter. These mice display a decrease in C16:0 containing sphingolipids. Relative to wild type tissues the amount of C16:0 containing sphingomyelin in kidney is ∼35%, whereas we find a reduction of C16:0 ceramide content in the small intestine to about 25%. The CerS6KO mice show behavioral abnormalities including a clasping abnormality of their hind limbs and a habituation deficit. LacZ reporter expression in the brain reveals CerS6 expression in hippocampus, cortex, and the Purkinje cell layer of the cerebellum. Using newly developed antibodies that specifically recognize the CerS6 protein we show that the endogenous CerS6 protein is N-glycosylated and expressed in several tissues of mice, mainly kidney, small and large intestine, and brain.

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Ceramide Synthase 2 Null Mice Are Protected from Ovalbumin-Induced Asthma with Higher T Cell Receptor Signal Strength in CD4+ T Cells

International Journal of Molecular Sciences ◽

10.3390/ijms22052713 ◽

2021 ◽

Vol 22 (5) ◽

pp. 2713

Author(s):

Sun-Hye Shin ◽

Kyung-Ah Cho ◽

Hee-Soo Yoon ◽

So-Yeon Kim ◽

Hee-Yeon Kim ◽

...

Keyword(s):

T Cells ◽

T Cell ◽

T Cell Receptor ◽

Cd4 T Cells ◽

Acyl Chain ◽

Signal Strength ◽

Cell Receptor ◽

Ceramide Synthase ◽

Asthmatic Patients

(1) Background: six mammalian ceramide synthases (CerS1–6) determine the acyl chain length of sphingolipids (SLs). Although ceramide levels are increased in murine allergic asthma models and in asthmatic patients, the precise role of SLs with specific chain lengths is still unclear. The role of CerS2, which mainly synthesizes C22–C24 ceramides, was investigated in immune responses elicited by airway inflammation using CerS2 null mice. (2) Methods: asthma was induced in wild type (WT) and CerS2 null mice with ovalbumin (OVA), and inflammatory cytokines and CD4 (cluster of differentiation 4)+ T helper (Th) cell profiles were analyzed. We also compared the functional capacity of CD4+ T cells isolated from WT and CerS2 null mice. (3) Results: CerS2 null mice exhibited milder symptoms and lower Th2 responses than WT mice after OVA exposure. CerS2 null CD4+ T cells showed impaired Th2 and increased Th17 responses with concomitant higher T cell receptor (TCR) signal strength after TCR stimulation. Notably, increased Th17 responses of CerS2 null CD4+ T cells appeared only in TCR-mediated, but not in TCR-independent, treatment. (4) Conclusions: altered Th2/Th17 immune response with higher TCR signal strength was observed in CerS2 null CD4+ T cells upon TCR stimulation. CerS2 and very-long chain SLs may be therapeutic targets for Th2-related diseases such as asthma.

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Abstract 16607: Age-induced Endoplasmic Reticulum Stress in the Heart: Role of Increased Very Long-chain Ceramides

Circulation ◽

10.1161/circ.142.suppl_3.16607 ◽

2020 ◽

Vol 142 (Suppl_3) ◽

Author(s):

Qun Chen ◽

Anna Kovilakath ◽

Jeremy Allegood ◽

Lauren A Cowart ◽

Edward J Lesnefsky

Keyword(s):

Er Stress ◽

Mitochondrial Dysfunction ◽

Acyl Chain ◽

Membrane Domains ◽

Ceramide Synthase ◽

Age Related ◽

Chain Lengths ◽

Endoplasm Reticulum ◽

Long Chain

Introduction: Mitochondrial function is impaired in aged hearts. Increased endoplasm reticulum (ER) stress contributes to the mitochondrial dysfunction observed during aging. Ceramides (CRMD) are sphingolipid metabolites that contribute key roles in cell signaling. Increased CRMD can lead to ER stress. Ceramide synthase enzymes (CerS) generate chain length specific CRMD with the CerS isoform 2 (Cers2) forming very long chain CRMD of ≥ 20 carbon acyl chain lengths. Hypothesis: An increase in CRMD content during aging contributes to age-related ER stress. Methods: Male mice (3, 18, 24 mo.) from the NIA colony were studied. Cardiac mitochondria (MITO), mitochondrial associated membranes (MAM), and ER were isolated from mouse hearts. CRMD content was measured using LC-MS. The contents of CerS enzymes were measured by immunoblotting in myocardial homogenates. Results: ER stress increased progressively during aging with increased contents of cleaved ATF6 and CHOP, indicators of increased ER stress, evident at 18 and 24 mo. (Panel A) (all data mean±SEM; *p<0.05 vs. 3 mo., † p<0.05 vs. 18 mo.). Aging increased very long-chain CRMD (≥C20) in ER (Panel B) at 18 and 24 mo. Similar CRMD trends were observed MAM (Panel C), shared membrane domains where ER and MITO interact. The content of CerS2 was increased at 24 mo. compared to 3 mo. (Panel D, n=4 each age). In contrast, the contents of CerS isoforms 4 and 5, that generate shorter chain CRMD (<C20) were unchanged (not shown). CRMD contents in MITO were unaltered with age (not shown). Thus, increased generation of very long chain CRMD in the ER is the likely mechanism of increased ER stress in the aged heart. Conclusion: Aging increased ER CRMD content by enhancing the formation of very long chain CRMD in ER by an increase in CerS2 content, concomitant with the onset of ER stress. The increase in age-induced ER stress, in turn, leads to mitochondrial dysfunction in the aged heart.

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The role of adenine nucleotide carrier and of residual phospholipids in the reconstitution of mitochondrial ATPase complex with phosphatidylcholines of different acyl-chain length

Cell Biology International Reports ◽

10.1016/s0309-1651(86)80009-1 ◽

1986 ◽

Vol 10 (3) ◽

pp. 155-155

Author(s):

F DABBENISALA

Keyword(s):

Chain Length ◽

Adenine Nucleotide ◽

Acyl Chain ◽

Mitochondrial Atpase ◽

Acyl Chain Length

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DR5 Knockout Mice Are Compromised in Radiation-Induced Apoptosis

Molecular and Cellular Biology ◽

10.1128/mcb.25.5.2000-2013.2005 ◽

2005 ◽

Vol 25 (5) ◽

pp. 2000-2013 ◽

Cited By ~ 77

Author(s):

Niklas Finnberg ◽

Joshua J. Gruber ◽

Peiwen Fei ◽

Dorothea Rudolph ◽

Anka Bric ◽

...

Keyword(s):

Cell Death ◽

Null Mouse ◽

Organ Specific ◽

Radiation Induced ◽

Induced Apoptosis ◽

The Brain ◽

Necrosis Factor

ABSTRACT DR5 (also called TRAIL receptor 2 and KILLER) is an apoptosis-inducing membrane receptor for tumor necrosis factor-related apoptosis-inducing ligand (also called TRAIL and Apo2 ligand). DR5 is a transcriptional target of p53, and its overexpression induces cell death in vitro. However, the in vivo biology of DR5 has remained largely unexplored. To better understand the role of DR5 in development and in adult tissues, we have created a knockout mouse lacking DR5. This mouse is viable and develops normally with the exception of having an enlarged thymus. We show that DR5 is not expressed in developing embryos but is present in the decidua and chorion early in development. DR5-null mouse embryo fibroblasts expressing E1A are resistant to treatment with TRAIL, suggesting that DR5 may be the primary proapoptotic receptor for TRAIL in the mouse. When exposed to ionizing radiation, DR5-null tissues exhibit reduced amounts of apoptosis compared to wild-type thymus, spleen, Peyer's patches, and the white matter of the brain. In the ileum, colon, and stomach, DR5 deficiency was associated with a subtle phenotype of radiation-induced cell death. These results indicate that DR5 has a limited role during embryogenesis and early stages of development but plays an organ-specific role in the response to DNA-damaging stimuli.

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Probing the Role of the Ceramide Acyl Chain Length and Sphingosine Unsaturation in Model Skin Barrier Lipid Mixtures by 2H Solid-State NMR Spectroscopy

Langmuir ◽

10.1021/acs.langmuir.5b00751 ◽

2015 ◽

Vol 31 (17) ◽

pp. 4906-4915 ◽

Cited By ~ 30

Author(s):

Sören Stahlberg ◽

Barbora Školová ◽

Perunthiruthy K. Madhu ◽

Alexander Vogel ◽

Kateřina Vávrová ◽

...

Keyword(s):

Solid State ◽

Nmr Spectroscopy ◽

Chain Length ◽

Solid State Nmr ◽

Acyl Chain ◽

Skin Barrier ◽

Solid State Nmr Spectroscopy ◽

Acyl Chain Length ◽

Lipid Mixtures

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Role of acyl-CoAs and acyl-CoA-binding protein in regulation of carbon supply for fatty acid biosynthesis

Biochemical Society Transactions ◽

10.1042/bst0280672 ◽

2000 ◽

Vol 28 (6) ◽

pp. 672-674 ◽

Cited By ~ 5

Author(s):

S. R. Fox ◽

S. Rawsthorne ◽

M. J. Hills

Keyword(s):

Fatty Acid Biosynthesis ◽

Binding Protein ◽

Acyl Chain ◽

P Uptake ◽

Embryo Maturation ◽

Acid Biosynthesis ◽

Acyl Chain Length ◽

Carbon Supply ◽

Ic50 Values

Acyl-CoA esters inhibit the plastidial glucose 6-phosphate (Glc-6-P) transporter and the adenylate transporter; the IC50 values for the inhibition by oleoyl-CoA (18:1-CoA) are 200–400 nM and 1–2 μM respectively. The inhibition of either of these processes significantly reduces the flux of carbon from Glc-6-P or from acetate into longchain fatty acids. The effect is dependent on the acyl chain length, e.g. lauryl-CoA is less inhibitory than oleoyl-CoA, causing 34 and 68% inhibition respectively of Glc-6-P uptake after 30 s. The inhibition of Glc-6-P and ATP transport is alleviated by addition of an equivalent concentration of acyl-CoA-binding protein (ACBP) or BSA. Acyl-CoAs do not inhibit pyruvate or glucose transporters. The endogenous concentrations of acyl-CoAs and ACBP are similar during embryo maturation.

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