Relevant bibliographies by topics / Ceramidase

Academic literature on the topic 'Ceramidase'

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Published: 6 September 2023

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Journal articles on the topic "Ceramidase"

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Yuan, Changqing, Raghavendra Pralhada Rao, Nahid Jesmin, Takeshi Bamba, Kunio Nagashima, Alberto Pascual, Thomas Preat, Eiichiro Fukusaki, Usha Acharya, and Jairaj K. Acharya. "CDase is a pan-ceramidase in Drosophila." Molecular Biology of the Cell 22, no. 1 (January 2011): 33–43. http://dx.doi.org/10.1091/mbc.e10-05-0453.

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Ceramidases catalyze the conversion of ceramide to sphingosine. They are acylaminohydrolases that catalyze the deacylation of the amide-linked saturated fatty acid from ceramide to generate sphingosine. They also catalyze the reverse reaction of ceramide biosynthesis using sphingosine and fatty acid. In mammals, different proteins catalyze these reactions while individually exhibiting optimal activity over a narrow pH range and have been accordingly called acid, neutral, and alkaline ceramidases. Several genes encode for variants of alkaline ceramidase in mammals. Brainwashing (Bwa) is the only putative alkaline ceramidase homologue present in Drosophila. In this study we have demonstrated that BWA does not exhibit ceramidase activity and that bwa null mutants display no loss of ceramidase activity. Instead, the neutral ceramidase gene CDase encodes the protein that is responsible for all measurable ceramidase activity in Drosophila. Our studies show strong genetic interaction of Bwa with CDase and the Drosophila ceramide kinase gene (DCERK). We show that, although BWA is unlikely to be a ceramidase, it is a regulator of sphingolipid flux in Drosophila. Bwa exhibits strong genetic interaction with other genes coding for ceramide-metabolizing enzymes. This interaction might partly explain its original identification as a ceramidase.
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Duarte, Carolina, Juliet Akkaoui, Chiaki Yamada, Anny Ho, Cungui Mao, and Alexandru Movila. "Elusive Roles of the Different Ceramidases in Human Health, Pathophysiology, and Tissue Regeneration." Cells 9, no. 6 (June 2, 2020): 1379. http://dx.doi.org/10.3390/cells9061379.

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Ceramide and sphingosine are important interconvertible sphingolipid metabolites which govern various signaling pathways related to different aspects of cell survival and senescence. The conversion of ceramide into sphingosine is mediated by ceramidases. Altogether, five human ceramidases—named acid ceramidase, neutral ceramidase, alkaline ceramidase 1, alkaline ceramidase 2, and alkaline ceramidase 3—have been identified as having maximal activities in acidic, neutral, and alkaline environments, respectively. All five ceramidases have received increased attention for their implications in various diseases, including cancer, Alzheimer’s disease, and Farber disease. Furthermore, the potential anti-inflammatory and anti-apoptotic effects of ceramidases in host cells exposed to pathogenic bacteria and viruses have also been demonstrated. While ceramidases have been a subject of study in recent decades, our knowledge of their pathophysiology remains limited. Thus, this review provides a critical evaluation and interpretive analysis of existing literature on the role of acid, neutral, and alkaline ceramidases in relation to human health and various diseases, including cancer, neurodegenerative diseases, and infectious diseases. In addition, the essential impact of ceramidases on tissue regeneration, as well as their usefulness in enzyme replacement therapy, is also discussed.
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Parveen, Farzana, Daniel Bender, Shi-Hui Law, Vineet Kumar Mishra, Chih-Chieh Chen, and Liang-Yin Ke. "Role of Ceramidases in Sphingolipid Metabolism and Human Diseases." Cells 8, no. 12 (December 4, 2019): 1573. http://dx.doi.org/10.3390/cells8121573.

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Human pathologies such as Alzheimer’s disease, type 2 diabetes-induced insulin resistance, cancer, and cardiovascular diseases have altered lipid homeostasis. Among these imbalanced lipids, the bioactive sphingolipids ceramide and sphingosine-1 phosphate (S1P) are pivotal in the pathophysiology of these diseases. Several enzymes within the sphingolipid pathway contribute to the homeostasis of ceramide and S1P. Ceramidase is key in the degradation of ceramide into sphingosine and free fatty acids. In humans, five different ceramidases are known—acid ceramidase, neutral ceramidase, and alkaline ceramidase 1, 2, and 3—which are encoded by five different genes (ASAH1, ASAH2, ACER1, ACER2, and ACER3, respectively). Notably, the neutral ceramidase N-acylsphingosine amidohydrolase 2 (ASAH2) shows considerable differences between humans and animals in terms of tissue expression levels. Besides, the subcellular localization of ASAH2 remains controversial. In this review, we sum up the results obtained for identifying gene divergence, structure, subcellular localization, and manipulating factors and address the role of ASAH2 along with other ceramidases in human diseases.
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Jin, K., Y. Higaki, Y. Takagi, K. Higuchi, Y. Yada, M. Kawashima, and G. Imokawa. "Analysis of beta-glucocerebrosidase and ceramidase activities in atopic and aged dry skin." Acta Dermato-Venereologica 74, no. 5 (September 1, 1994): 337–40. http://dx.doi.org/10.2340/0001555574341343.

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To elucidate the mechanisms that are involved in the decrease of ceramide levels in atopic dry skin and in aged skin, we examined both the activities of beta-glucocerebrosidase, which is a major enzyme in ceramide production, and of ceramidase, which is an essential enzyme in ceramide degradation, in the stratum corneum of atopic dry skin and aged skin. The specimens of the stratum corneum of forearm skin were obtained by tape-stripping from 61 healthy volunteers and 23 patients with atopic uninvolved skin. The beta-glucocerebrosidase activity in the stratum corneum extracts was estimated using fluorescent 4-methylumbelliferyl-beta-D-glucopyranoside as the substrate. Ceramidase activity was determined using 14C-palmitoylsphingosine as the substrate. Among the atopic skin samples, neither beta-glucocerebrosidase nor ceramidase activities were different from those of age-matched healthy controls. Nor was the beta-glucocerebrosidase activity deficient in the aged skin samples as compared to that seen in samples from the young, healthy group. In contrast, there was an age-related upregulation in ceramidase activity. The results indicate that the decrease of ceramides in atopic dry skin may not be accompanied by reduced synthesis or by enhanced degradation, each of which is primarily attributable to the above two enzymes, respectively. The pathogenesis of aged dry skin can be explained, at least partially, in terms of elevated ceramidase activity, which results in a disturbance of the lamellar structure of the stratum corneum lipids.
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Ramachandra, Nagaraju, and Andreas Conzelmann. "Membrane topology of yeast alkaline ceramidase YPC1." Biochemical Journal 452, no. 3 (May 31, 2013): 585–94. http://dx.doi.org/10.1042/bj20130085.

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Ypc1p (yeast phyto-ceramidase 1) and Ydc1p (yeast dihydroceramidase 1) are alkaline ceramide hydrolases that reside in the ER (endoplasmic reticulum). Ypc1p can catalyse the reverse reaction, i.e. the condensation of non-esterified fatty acids with phytosphingosine or dihydrosphingosine and overexpression of YPC1 or YDC1 can provide enough ceramide synthesis to rescue the viability of cells lacking the normal acyl-CoA-dependent ceramide synthases. To better understand the coexistence of acyl-CoA-dependent ceramide synthases and ceramidases in the ER we investigated the membrane topology of Ypc1p by probing the cysteine residue accessibility of natural and substituted cysteines with membrane non-permeating mass-tagged probes. The N- and C-terminal ends of Ypc1p are oriented towards the lumen and cytosol respectively. Two of the five natural cysteines, Cys27 and Cys219, are essential for enzymatic activity and form a disulfide bridge. The data allow the inference that all of the amino acids of Ypc1p that are conserved in the Pfam PF05875 ceramidase motif and the CREST {alkaline ceramidase, PAQR [progestin and adipoQ (adiponectin) receptor] receptor, Per1 (protein processing in the ER 1), SID-1 (sister disjunction 1) and TMEM8 (transmembrane protein 8)} superfamily are located in or near the ER lumen. Microsomal assays using a lysine residue-specific reagent show that the reverse ceramidase activity can only be blocked when the reagent has access to Ypc1p from the lumenal side. Overall the data suggest that the active site of Ypc1p resides at the lumenal side of the ER membrane.
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Zaibaq, Faris, Tyrone Dowdy, and Mioara Larion. "TMET-36. ACID CERAMIDASE INHIBITION EXPLOITS SPHINGOLIPID VULNERABILITIES IN IDH MUTANT GLIOMAS." Neuro-Oncology 24, Supplement_7 (November 1, 2022): vii269—vii270. http://dx.doi.org/10.1093/neuonc/noac209.1041.

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Abstract The presence of the IDH mutation in gliomas is a major classifier of brain tumor subtypes and has several important implications for cancer growth. Our recent work uncovered that IDH-mutant tumors are susceptible to increased apoptosis via alterations of the sphingolipid pathway due to their excess production of pro-apoptotic ceramides over pro-proliferative sphingosine 1-phosphate (S1P). To that end, we proposed that this rheostat can be modulated to induce cell death in IDHmut tumors by targeting acid ceramidase, a critical sphingolipid enzyme in gliomas. We hypothesize that pharmacological inhibition of acid ceramidase will increase ceramide levels and therefore induce apoptosis in IDHmutgliomas. Using a preliminary drug screen, we have identified a group of haloacetate C2-ceramide derivatives known as SOBRACs that potently inhibit acid ceramidase. We selected five candidate compounds from this family and assessed the effectiveness of each drug in 3 I IDHmut (BT142, TS603, & U251mut) and 3 IDHmut (GSC923, GSC827, U251wt) patient-derived glioma cell lines, as well as non-immortalized normal human astrocytes, using the CCK8 cell viability assay. Our results indicate that the SOBRAC drugs are nearly 10 times more potent in IDH-mutant tumors compared to IDHmut cell lines. Additionally, the SOBRAC drugs are more effective than other known acid ceramidase inhibitors, making them attractive as potential novel therapeutics. To date, azide-SOBRAC is the most potent drug in the family, with EC50 value of 300 nM in BT142 cells (IDHmutmut
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Proksch, Denny, Jan Jasper Klein, and Christoph Arenz. "Potent Inhibition of Acid Ceramidase by Novel B-13 Analogues." Journal of Lipids 2011 (2011): 1–8. http://dx.doi.org/10.1155/2011/971618.

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The lipid-signalling molecule ceramide is known to induce apoptosis in a variety of cell types. Inhibition of the lysosomal acid ceramidase can increase cellular ceramide levels and thus induce apoptosis. Indeed, inhibitors of acid ceramidase have been reported to induce cell death and to display potentiating effects to classical radio- or chemo therapy in a number ofin vitroandin vivocancer models. The most potentin vitroinhibitor of acid ceramidase, B-13, recently revealed to be virtually inactive towards lysosomal acid ceramidase in living cells. In contrast, a number of weakly basic B-13 analogues have been shown to accumulate in the acidic compartments of living cells and to efficiently inhibit lysosomal acid ceramidase. However, introduction of weakly basic groups at theω-position of the fatty acid moiety of B-13 led to a significant reduction of potency towards acid ceramidase from cellular extracts. Herein, we report a novel B-13-derived scaffold for more effective inhibitors of acid ceramidase. Furthermore, we provide hints for an introduction of basic functional groups at an alternative site of the B-13 scaffold that do not interfere with acid ceramidase inhibitionin vitro.
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Yi, Jae Kyo, Ruijuan Xu, Lina M. Obeid, Yusuf A. Hannun, Michael V. Airola, and Cungui Mao. "Alkaline ceramidase catalyzes the hydrolysis of ceramides via a catalytic mechanism shared by Zn2+-dependent amidases." PLOS ONE 17, no. 9 (September 1, 2022): e0271540. http://dx.doi.org/10.1371/journal.pone.0271540.

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Human alkaline ceramidase 3 (ACER3) is one of three alkaline ceramidases (ACERs) that catalyze the conversion of ceramide to sphingosine. ACERs are members of the CREST superfamily of integral-membrane hydrolases. All CREST members conserve a set of three Histidine, one Aspartate, and one Serine residue. Although the structure of ACER3 was recently reported, catalytic roles for these residues have not been biochemically tested. Here, we use ACER3 as a prototype enzyme to gain insight into this unique class of enzymes. Recombinant ACER3 was expressed in yeast mutant cells that lack endogenous ceramidase activity, and microsomes were used for biochemical characterization. Six-point mutants of the conserved CREST motif were developed that form a Zn-binding active site based on a recent crystal structure of human ACER3. Five point mutants completely lost their activity, with the exception of S77A, which showed a 600-fold decrease compared with the wild-type enzyme. The activity of S77C mutant was pH sensitive, with neutral pH partially recovering ACER3 activity. This suggested a role for S77 in stabilizing the oxyanion of the transition state. Together, these data indicate that ACER3 is a Zn2+-dependent amidase that catalyzes hydrolysis of ceramides via a similar mechanism to other soluble Zn-based amidases. Consistent with this notion, ACER3 was specifically inhibited by trichostatin A, a strong zinc chelator.
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Olsson, Maria, Rui-Dong Duan, Lena Ohlsson, and Åke Nilsson. "Rat intestinal ceramidase: purification, properties, and physiological relevance." American Journal of Physiology-Gastrointestinal and Liver Physiology 287, no. 4 (October 2004): G929—G937. http://dx.doi.org/10.1152/ajpgi.00155.2004.

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Neutral ceramidase activity has previously been identified in the intestinal mucosa and gut lumen and postulated to be important in the digestion of sphingolipids. It is found throughout the intestine but has never been fully characterized. We have purified rat intestinal neutral ceramidase from an eluate obtained by perfusing the intestinal lumen with 0.9% NaCl and 3 mM sodium taurodeoxycholate. Using a combination of acetone precipitation and ion-exchange, hydrophobic-interaction, and gel chromatographies, we obtained a homogenous enzyme protein with a molecular mass of ∼116 kDa. The enzyme acts on both [14C]octanoyl- and [14C]palmitoyl-sphingosine in the presence of glycocholic and taurocholic acid and the bile salt analog 3-[(3-cholamidopropyl)dimethylammonio]-1-propanesulfonate but is inhibited by 2 mM or more of other bile salts. It is a glycosylated protein stable to trypsin and chymotrypsin exposure, is not influenced by Ca2+, Mg2+, or Mn2+, and is inhibited by Zn2+ and Cu2+. Mass fragmentographic analysis identified 12 fragments covering 17.5% of the sequence for neutral/alkaline ceramidase 2 purified (Mitsutake S, Tani M, Okino N, Mori K, Ichinose S, Omori A, Iida H, Nakamura T, and Ito M. J Biol Chem 276: 26249–262459, 2001) from rat kidney and located in apical membrane of renal tubular cells. Intestinal and kidney ceramidases also have similar molecular mass and ion dependence. Intestinal ceramidase thus is a neutral ceramidase 2 released by bile salts and resistant to pancreatic proteases. It is well suited to metabolize ceramide formed from dietary and brush border sphingolipids to generate other bioactive sphingolipid messengers.
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BIONDA, Clara, Jacques PORTOUKALIAN, Daniel SCHMITT, Claire RODRIGUEZ-LAFRASSE, and Dominique ARDAIL. "Subcellular compartmentalization of ceramide metabolism: MAM (mitochondria-associated membrane) and/or mitochondria?" Biochemical Journal 382, no. 2 (August 24, 2004): 527–33. http://dx.doi.org/10.1042/bj20031819.

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Recent studies by our group and others have disclosed the presence of ceramides in mitochondria, and the activities of ceramide synthase and reverse ceramidase in mitochondria have also been reported. Since a possible contamination with the ER (endoplasmic reticulum)-related compartment MAM (mitochondria-associated membrane) could not be ruled out in previous studies, we have re-investigated the presence of the enzymes of ceramide metabolism in mitochondria and MAM highly purified from rat liver. In the present paper, we show that purified mitochondria as well as MAM are indeed able to generate ceramide in vitro through both ceramide synthase or reverse ceramidase, whereas the latter enzyme activity is barely detectable in microsomes. Moreover, ceramide synthase activities were recovered in outer mitochondrial membranes as well as in inner mitochondrial membranes. Using radiolabelled sphingosine as a substrate, mitochondria could generate ceramide and phytoceramide. However, the in vitro sensitivity of ceramide synthase toward FB1 (fumonisin B1) in mitochondria as well as in MAM was found to depend upon the sphingoid base: whereas dihydrosphingosine N-acyltransferase was inhibited by FB1 in a concentration-dependent manner, FB1 actually activated the ceramide synthase when using sphingosine as a substrate. Acylation of sphingosine 1-phosphate and dihydrosphingosine 1-phosphate, generating ceramide 1-phosphate, was also shown with both subcellular fractions. Moreover, the same difference in sensitivity towards FB1 for the ceramide synthase activities was seen between the two phosphorylated sphingoid bases, raising the possibility that distinct base-specific enzymes may be involved as ceramide synthases. Collectively, these results demonstrate the involvement of mitochondria in the metabolism of ceramides through different pathways, thereby supporting the hypothesis that topology of ceramide formation could determine its function.
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Dissertations / Theses on the topic "Ceramidase"

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Bayerle, Aline [Verfasser]. "Physiologische Konsequenzen eines gestörten Ceramid Stoffwechsels unter Beteiligung von Ceramidsynthase 3 und saurer Ceramidase = Physiological consequences of a disturbed ceramide metabolism due to altered activities of ceramide synthase 3 and acidic ceramidase / Aline Bayerle." Mainz : Universitätsbibliothek der Johannes Gutenberg-Universität Mainz, 2015. http://d-nb.info/1225685362/34.

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Goltz, Gerit. "Charakterisierung von Ceramidase-Inhibitoren an der humanen Keratinozyten-Zellinie HaCaT." [S.l.] : [s.n.], 2002. http://www.diss.fu-berlin.de/2002/180/index.html.

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Lucki, Natasha Chrystman. "Characterization of the role of acid ceramidase in adrenocortical steroid hormone biosynthesis." Diss., Georgia Institute of Technology, 2011. http://hdl.handle.net/1853/42804.

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Sphingolipids modulate multiple cellular functions, including steroid hormone biosynthesis. Sphingosine is an antagonist ligand for the nuclear receptor steroidogenic factor 1 (SF-1), which is the primary transcriptional regulator of most steroidogenic genes. Furthermore, sphingosine-dependent repression of SF-1 function is dependent on the expression of acid ceramidase (ASAH1), an enzyme that forms sphingosine. Based on these data, I hypothesized that ACTH/cAMP signaling regulates ASAH1 function at both transcriptional and post-transcriptional levels. In addition, because SF-1 is predominantly a nuclear protein, I postulated that ASAH1 modulates SF-1 function and, therefore, steroidogenic gene expression by controlling the nuclear concentrations of SPH. To test these hypotheses, I first examined the effect of chronic ACTH/cAMP signaling on the transcription of the ASAH1 gene. Next, the functional significance of ASAH1 expression in adrenocortical cells was probed by generating an ASAH1-knockdown cell line. I subsequently characterized the role of ASAH1 as a transcriptional nuclear receptor coregulator. Finally, I defined the role of sphingosine-1-phosphate, a bi-product of ASAH1 activity, in the acute phase of cortisol biosynthesis. Using a variety of experimental approaches, I identified cAMP response element binding protein as an essential transcriptional activator of the ASAH1 gene. Analysis of adrenocortical cells lacking ASAH1 revealed that ASAH1 is a global regulator of steroidogenic capacity. Furthermore, I identified ASAH1 as a nuclear protein and defined the molecular determinants of the interaction between ASAH1 and SF-1. Collectively, this body of work establishes the integral role of ASAH1 in the regulation of ACTH-dependent adrenocortical cortisol biosynthesis.
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Li, Guangbi. "Podocyte Dedifferentiation and Glomerular Injury Mediated by Lysosome Dysfunction: Role of Acid Ceramidase." VCU Scholars Compass, 2017. https://scholarscompass.vcu.edu/etd/5169.

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Cell differentiation and senescence in podocytes are attributed to normal autophagy and associated cellular activities. It is possible that derangement of autophagy under different pathological conditions activates or enhances podocyte dedifferentiation leading to glomerular injury and ultimate glomerular disease. To test this hypothesis, we first tested whether autophagic deficiency due to lysosome dysfunction enhances podocyte dedifferentiation and explored the molecular mechanisms by which this lysosome dysfunction trigger or enhance podocyte dedifferentiation. By Western blot and confocal analysis, lysosome inhibition using an inhibitor or siRNA of V-ATPase inhibitor was found to markedly decrease the epithelial markers (P-cadherin and ZO-1) and increase the mesenchymal markers (FSP-1 and α-SMA). This enhancement of podocyte dedifferentiation (formerly referred to as epithelial-mesenchymal transition, EMT) was accompanied by deficient autophagic flux, as demonstrated by marked increases in LC3B-II and p62/Sequestosome 1. However, inhibition of autophagosome formation using spautin-1 (SP-1) significantly attenuated both enhancement of podocyte dedifferentiation and deficiency of autophagic flux. To explore the mechanisms by which deficient autophagic flux enhances podocyte dedifferentiation, we tested the role of accumulated p62 as a signal hub in this process. Neither the nuclear factor erythroid 2-related factor 2 (Nrf2) nor nuclear factor kappa (NFκ)-light-chain-enhancer pathway regulating p62 function was found to contribute to enhanced dedifferentiation. However, inhibition of cyclin-dependent kinase 1 (CDK1) activity reduced the phosphorylation of p62 and enhanced podocyte dedifferentiation similar to lysosome dysfunction, which indicates that enhanced podocyte dedifferentiation due to lysosome dysfunction may be triggered by accumulation of p62 and associated reduction of p62 phosphorylation. Given the essential role of sphingolipid-ceramide metabolism and transient receptor potential-mucolipin-1 (TRPML1) channel activity in lysosome function, we next sought to test whether altered ceramide metabolism by acid ceramidase (AC) leads to deficient lysosome trafficking and fusion to autophagosome in podocytes and thereby results in autophagic deficiency and podocyte dedifferentiation. Inhibition of AC by a potent and selective inhibitor, carmofur markedly reduced lysosome trafficking and fusion to both autophagosomes and multivesicular bodies (MVBs). Concurrently, enhancement of podocyte AC activity or exposure of podocytes to sphingosine, a product of ceramide metabolism by AC, remarkably increased lysosome trafficking and fusion to autophagosomes and MVBs, indicating that AC activity is critical for lysosome function in podocytes. To further explore the mechanisms by which AC activity contributes to lysosome trafficking, we examined the effects of various sphingolipids related to ceramide metabolism on transient receptor potential-mucolipin-1 (TRPML1) channel, a Ca2+ channel essential for lysosome trafficking and function. It was found that sphingomyelin (SM), a precursor for ceramide production blocked TRPML1 channel activity induced by ML-SA1 (a specific TRPML1 agonist), while ceramide had no effects on TRPML1 channel activity induced by ML-SA1. Interestingly, sphingosine, an AC product of ceramide remarkably enhanced TRPML1 channel activity induced by ML-SA1. These results demonstrate that AC product of ceramide, sphingosine may enhance TRPML1 channel activity, but an upstream sphingolipid, SM may exert inhibitory action on lysosome TRPML1 channel activity. AC may be a key enzyme gating TRPML1 channels by production of sphingosine and changes in upstream substrate SM. These results from in vitro cell studies led us hypothesize that a deficient AC activity may induce podocyte injury through lysosome dysfunction, leading to glomerular damage and proteinuria. To test this hypothesis, we generated a mouse colony with podocyte-specific gene deletion of AC α subunit, namely, Asah1fl/fl/PodoCre mice. In these mice, severe proteinuria and albuminuria were shown compared to their littermates, but they were without global and even focal glomerular sclerosis. These mice also had hypoalbuminemia and edema, and under transmission electron microscopy (TEM) ultrastructural changes of podocytes from their glomeruli exhibited diffuse and flat foot process (podocyte effacement), vacuolation, and microvillus formation, which were not observed in their littermates. Treatment of corticosteroids and specific expression patterns of dystroglycans in glomeruli confirmed that albuminuria in these Asah1fl/fl/PodoCre mice may be resistant to corticosteroids. Together, these results from in vivo animal studies indicate that podocyte-specific gene deletion of AC α subunit may induce a corticosteroid-resistant minimal change disease (MCD). Based on all results from our in vitro and in vivo studies, we conclude that the normal lysosome function is essential for maintenance of autophagic flux and podocyte differentiation, which is regulated by a lysosomal AC-mediated signaling pathway through a TRPML1 channel gating mechanism. AC gene defect or deficiency of its activity induces podocyte injury, which is characterized by a corticosteroid-resistant MCD. These findings indicate an important pathological role of AC deficiency and associated lysosome dysfunction in podocytes injury and corticosteroid-resistant MCD, which may help develop novel therapeutic strategies for prevention or treatment of corticosteroid-resistant MCD.
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Camacho, Castillo Luz del Carmen. "Acid ceramidase and sphingosine-1-phosphate lyase as biomarkers and therapeutic targets in cancer. (Ceramidasa ácida y Esfingosina-1-fosfato Liasa como biomarcadores y dianas terapéuticas en cáncer)." Doctoral thesis, Universitat de Barcelona, 2011. http://hdl.handle.net/10803/21624.

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Cer and So are involved in regulation of apoptosis and cell cycle arrest while on the other hand S1P promotes cell growth and inhibits apoptosis. The antagonistic effects of these metabolites are regulated by enzymes that interconvert Cer, So, and S1P. In this work two of these enzymes were studied: sphingosine phosphate lyase and acid ceramidase. First several methods to determine the activity of these enzymes were developed and optimized, resulting in the publication of sensitive fluorogenic and chromatographic methods for enzyme activity. Particularly the assay optimized for acid ceramidase activity was used in the finding and identification of new inhibitors in several compound libraries. As a result compounds RBM2-1B, RBM2-1D and RBM2-1E were identified as acid ceramidase and dihydroceramide desaturase inhibitors. Furthermore compounds RBM1-12, RBM1-13 and SABRAC were also described as acid ceramidase inhibitors. Since several publications described the upregulation of acid ceramidase in advanced prostate cancer, we decided to investigate the particular effect of the acid ceramidase inhibition in a cellular model of advanced prostate cancer. Using cells PC-3/Mc we inhibited acid ceramidase through two different approaches: first silencing the gen ASAH1 and comparing the effects with chemical inhibition of the enzyme using compounds RBM1-12, RBM1-13 and SABRAC. We evaluate the effect of acid ceramidase inhibition in cell growth, invasivity and 3D growth in vitro, finding a diminished growth and 3D growth in both cells those knockdown for ASAH1 and treated with inhibitors. Finally, the effect of ASAH1 silencing in in vivo tumor growth and lung colonization was also determined. To this end male NOD-SCID mice were used for xenotransplants with cells PC-3/Mc_ASAH1_KD or control and the tumor growth or lung colonization was followed by luminometry. We found that the silencing of ASAH1 in PC-3/Mc cells delayed the growth and also the lung colonization, highlighting the potential of acid ceramidase inhibition as adjuvant in the treatment of prostate cancer and also in the prevention of metastases formation.
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Markus, Carolin [Verfasser]. "Die Funktion der putativen alkalischen Ceramidase ACER1 innerhalb des Sphingolipidstoffwechsels in Arabidopsis thaliana / Carolin Markus." Bonn : Universitäts- und Landesbibliothek Bonn, 2015. http://d-nb.info/1080864571/34.

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Fuchs, Kathrin [Verfasser], and Johannes [Akademischer Betreuer] Kornhuber. "Charakterisierung der Ceramidase-Aktivität im Plasma gesunder und alkoholabhängiger Probanden / Kathrin Fuchs. Gutachter: Johannes Kornhuber." Erlangen : Friedrich-Alexander-Universität Erlangen-Nürnberg (FAU), 2014. http://d-nb.info/1075478774/34.

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Meiners, Jana [Verfasser], and Astrid [Akademischer Betreuer] Westendorf. "The effect of the acid sphingomyelinase/ceramidase system on bacterial induced colitis / Jana Meiners ; Betreuer: Astrid Westendorf." Duisburg, 2019. http://d-nb.info/1191692159/34.

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Drosos, Zacharias [Verfasser], Lars [Akademischer Betreuer] Hanker, and Markus [Akademischer Betreuer] Meier. "Die prognostische Bedeutung der Expression von Acid-Ceramidase (ASAH1) und Sphingosin-Kinase 1 (SPHK1) bei Patientinnen mit Ovarialkarzinom / Zacharias Drosos ; Akademische Betreuer: Lars Hanker, Markus Meier." Lübeck : Zentrale Hochschulbibliothek Lübeck, 2021. http://d-nb.info/1236386272/34.

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Yamakawa, Nathália Christina Gonçalves 1986. "Epilepsia e Morita-Baylis-Hillman : uma abordagem sintética para ceramidas antiepiléticas." [s.n.], 2012. http://repositorio.unicamp.br/jspui/handle/REPOSIP/250239.

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Orientador: Fernando Antonio Santos Coelho
Dissertação (mestrado) - Universidade Estadual de Campinas, Instituto de Química
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Resumo: A epilepsia é uma das principais doenças do sistema nervoso central, caracterizada por uma alteração na atividade elétrica do cérebro, que leva a perdas de memória e convulsões. Essa doença afeta cerca de 50 milhões de pessoas no mundo, que são discriminadas e isoladas da sociedade. Existem vários medicamentos que podem ser utilizados, no entanto, muitas vezes é necessário a administração de associações desses que apresentam severos efeitos colaterais. Esse quadro justifica a necessidade da busca por substâncias mais eficientes para o tratamento dessa doença. Em 2008, Ahmed e cols. isolaram da esponja marinha Negombata corticata duas ceramidas que apresentaram importante atividade anti-convulsiva. Assim, este trabalho teve por objetivo estabelecer uma estratégia sintética para a preparação do fragmento polar de tais ceramidas. A rota foi baseada em um aduto de Morita-Baylis-Hillman (MBH), obtido com elevada diastereosseletividade a partir de uma reação entre o aldeído de Garner e o acrilato de etila. Uma reação de ozonólise na dupla ligação do aduto de MBH fornece um a-cetoéster, cuja carbonila cetônica e reduzida conduzindo a um único produto. A proteção das hidroxilas, permitiu a confirmação da estereoquímica relativa através de análise por difração de raios-X, que também evidenciou a ocorrência de racemização na reação de MBH. O diol também foi utilizado na preparação de um aza-açúcar, potencial inibidor de glicosidase, sendo esta síntese em apenas 4 etapas com 32% de rendimento global. A fração apolar da ceramida foi sintetizada a partir de uma reação de Grignard, e a junção dos fragmentos pode ser realizada utilizando-se uma reação de Wittig. Desta maneira, foi descrita uma nova estratégia sintética que pode ser aplicada na preparação de diversos análogos das ceramidas, desenvolvendo um antiepiléptico mais potente
Abstract: Epilepsy is a chronic brain disorder that affects around 50 million people all over the world. It is characterized by recurrent seizures - which are physical reactions to sudden excessive electrical discharges in a group of brain cells. The discrimination and social stigma that surround epilepsy worldwide are often more difficult to overcome than the seizures themselves. Because of this fact and the economical impacts of the disease, the research for new biologically active compounds is still necessary. In 2008, Ahmed et al. isolated from the Red Sea sponge Negombata corticata two ceramides, which exhibit in vivo anticonvulsant activity. This work is focused on establishing of a synthetic sequence to prepare the polar fragment present in both ceramides. The strategy was based on a Morita-Baylis-Hillman reaction between a Garner¿s aldehyde and ethyl acrylate that provided a functionalized intermediate in good diastereoselectivity. The major diastereoisomer was employed as substrate in an ozonolysis reaction, followed by a stereoselective reduction that afforded 1,2-diol as a single isomer. The acetonide derived from this 1,2-diol allowed us to determine through X-Ray diffraction analysis the relative stereochemistry of this compound as being 1,2- anti. To finish the synthesis of the polar fragment, the ester group present in the acetonide was reduced to the corresponding aldehyde. The diol also was applied in a high diastereoselective preparation of an azasugar in 4 steps and 32% yield overall. In this work we also describe the synthesis of a carbon chain of the ceramide, our route includes an approach to the apolar fragment obtained by a Grignard reaction; then a Wittig reaction can couple both fragments toward the finalization of the sphingosine¿s synthesis. Our synthetic route can also be used in the preparation of several analogues of the antiepiletic ceramides
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Books on the topic "Ceramidase"

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Futerman, Anthony H., ed. Ceramide Signaling. Boston, MA: Springer US, 2002. http://dx.doi.org/10.1007/978-1-4419-9272-7.

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Stiban, Johnny, ed. Bioactive Ceramides in Health and Disease. Cham: Springer International Publishing, 2019. http://dx.doi.org/10.1007/978-3-030-21162-2.

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Baker, Alison Dawn. Role of ceramide in induction of Fos, Jun, and collagenase in chondrocytes. Ottawa: National Library of Canada = Bibliothèque nationale du Canada, 1999.

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Sedel, Frédéric. Krabbe Disease in Adults. Oxford University Press, 2016. http://dx.doi.org/10.1093/med/9780199972135.003.0051.

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Krabbe disease (globoid cell leukodystrophy) is an autosomal recessive lysosomal storage disease caused by mutations in the lysosomal galactocerebrosidase (galactosyl ceramidase) gene. Krabbe disease usually presents as a severe leukodystrophy in early infancy and childhood. In contrast, adult patients usually present with progressive spastic paraparesis. Other signs of the disease include peripheral neuropathy, dysarthria, cerebellar ataxia, pes cavus deep sensory signs, tongue atrophy, optic neuropathy, cognitive decline. Cerebrospinal fluid protein concentration is moderately increased in adults. High signals of cortico-spinal tracts on brain MRI are highly suggestive and this typical aspect may be associated with hyper-intensities of optic radiations, and of the posterior part of the corpus callosum.
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H, Futerman Anthony, ed. Ceramide signaling. Georgetown, Tex. U.S.A: Landes Bioscience/Eurekah.com, 2002.

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Futerman, Anthony H. Ceramide Signaling. Springer, 2012.

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Futerman, Anthony H. Ceramide Signaling. Springer, 2003.

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Overloop, Helena Van. Metabolism & Biological Activities of C(2)-ceramide. Leuven Univ Pr, 2006.

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Summers, Scott A., and William Louis Holland, eds. The Role of Ceramides in Diabetes and Cardiovascular Disease. Frontiers Media SA, 2021. http://dx.doi.org/10.3389/978-2-88966-736-9.

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Watkins, Cecilia L. Sphingomyelin and Ceramides: Occurrence, Biosynthesis and Role in Disease. Nova Science Publishers, Incorporated, 2015.

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Book chapters on the topic "Ceramidase"

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Tani, Motohiro, and Makoto Ito. "Neutral Ceramidase." In Encyclopedia of Signaling Molecules, 3450–57. Cham: Springer International Publishing, 2018. http://dx.doi.org/10.1007/978-3-319-67199-4_101723.

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Tani, Motohiro, and Makoto Ito. "Neutral Ceramidase." In Encyclopedia of Signaling Molecules, 1–8. New York, NY: Springer New York, 2016. http://dx.doi.org/10.1007/978-1-4614-6438-9_101723-1.

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Scharnagl, Hubert, Winfried März, Markus Böhm, Thomas A. Luger, Federico Fracassi, Alessia Diana, Thomas Frieling, et al. "Acid Ceramidase Deficiency." In Encyclopedia of Molecular Mechanisms of Disease, 12. Berlin, Heidelberg: Springer Berlin Heidelberg, 2009. http://dx.doi.org/10.1007/978-3-540-29676-8_8522.

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Mckay, Charles P. "Ceramidase and Signal Transduction." In Sphingolipid-Mediated Signal Transduction, 173–81. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-662-22425-0_12.

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Norris, James S., David H. Holman, Marc L. Hyer, Alicja Bielawska, Ahmed El-Zawahry, Charles Chalfant, Charles Landen, et al. "Ceramide, Ceramidase, and FasL Gene Therapy in Prostate Cancer." In Death Receptors in Cancer Therapy, 323–38. Totowa, NJ: Humana Press, 2005. http://dx.doi.org/10.1385/1-59259-851-x:323.

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Ito, Makoto, Nozomu Okino, Motohiro Tani, Susumu Mitsutake, and Katsuhiro Kita. "Molecular Evolution of Neutral Ceramidase: From Bacteria to Mammals." In Ceramide Signaling, 41–48. Boston, MA: Springer US, 2002. http://dx.doi.org/10.1007/978-1-4419-9272-7_5.

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Mao, Cungui, and Lina Obeid. "Ceramidases: Regulators of Turnover of Ceramide and Ceramide-Mediated Responses." In Ceramide Signaling, 29–40. Boston, MA: Springer US, 2002. http://dx.doi.org/10.1007/978-1-4419-9272-7_4.

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Ito, Makoto, Motohiro Tani, and Yukihiro Yoshimura. "Neutral Ceramidase as an Integral Modulator for the Generation of S1P and S1P-Mediated Signaling." In Sphingolipid Biology, 183–96. Tokyo: Springer Japan, 2006. http://dx.doi.org/10.1007/4-431-34200-1_13.

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El Bawab, Samer, Cungui Mao, Lina M. Obeid, and Yasuf A. Hannun. "Ceramidases in the Regulation of Ceramide Levels and Function." In Subcellular Biochemistry, 187–205. Boston, MA: Springer US, 2004. http://dx.doi.org/10.1007/0-306-47931-1_10.

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Nikolova-Karakashian, Mariana, Teresa R. Vales, Elaine Wang, David S. Menaldino, Christopher Alexander, Jane Goh, Dennis C. Liotta, and Alfred H. Merrill. "Ceramide Synthase and Ceramidases in the Regulation of Sphingoid Base Metabolism." In Sphingolipid-Mediated Signal Transduction, 159–72. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-662-22425-0_11.

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Conference papers on the topic "Ceramidase"

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Flowers, Margaret, Gemma Fabriás, Antonio Delgado, Josefina Casas, and Myles C. Cabot. "Abstract 5484: Targeted inhibition of acid ceramidase and C6-ceramide exposure induces synergistic killing in cancer cells." In Proceedings: AACR 102nd Annual Meeting 2011‐‐ Apr 2‐6, 2011; Orlando, FL. American Association for Cancer Research, 2011. http://dx.doi.org/10.1158/1538-7445.am2011-5484.

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Turner, Lorianne S., Stephen Dungee, Frank Pezzimenti, and Margot Weatherford. "Abstract 4894: Effect of lysosome destabilization on response to ceramide in prostate cancer cells over-expressing acid ceramidase." In Proceedings: AACR 103rd Annual Meeting 2012‐‐ Mar 31‐Apr 4, 2012; Chicago, IL. American Association for Cancer Research, 2012. http://dx.doi.org/10.1158/1538-7445.am2012-4894.

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Sebti, Said M., Norbert Berndt, Ronil Patel, Hua Yang, and Maria Balasis. "Abstract 4522: Akt2 and acid ceramidase cooperate to induce malignant transformation." In Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA. American Association for Cancer Research, 2014. http://dx.doi.org/10.1158/1538-7445.am2014-4522.

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Pearson, Jennifer M., Su-Fern Tan, Arati Sharma, Todd E. Fox, Jose Luis Abad, Gemma Fabrias, David F. Claxton, David J. Feith, Mark Kester, and Thomas P. Loughran. "Abstract 48: Acid ceramidase inhibition: A targeted therapy for acute myeloid leukemia." In Abstracts: Second AACR Conference on Hematologic Malignancies: Translating Discoveries to Novel Therapies; May 6-9, 2017; Boston, MA. American Association for Cancer Research, 2017. http://dx.doi.org/10.1158/1557-3265.hemmal17-48.

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Tani, Motohiro, Hiroshi Iida, and Makoto Ito. "O-GLYCOSYLATION OF MUCIN-LIKE DOMAIN RECRUITS RAT NEUTRAL CERAMIDASE TO OUTER LEAFLETS OF PLASMA MEMBRANE." In XXIst International Carbohydrate Symposium 2002. TheScientificWorld Ltd, 2002. http://dx.doi.org/10.1100/tsw.2002.563.

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Tan, Su-Fern, Xin Liu, Kenichiro Doi, Hong-Gang Wang, Myles Cabot, David Feith, and Thomas P. Loughran. "Abstract 761: Acid ceramidase promotes drug resistance in acute myeloid leukemia through P-gp upregulation mediated by NF- kB activation." In Proceedings: AACR Annual Meeting 2014; April 5-9, 2014; San Diego, CA. American Association for Cancer Research, 2014. http://dx.doi.org/10.1158/1538-7445.am2014-761.

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Lezhniova, Vera Runarovna, Ekaterina Vladimirovna Martynova, Timur Il'dusovich Khaibullin, Ilnur Il'dusovich Salafutdinov, Mariia Ivanovna Markelova, Aleksandr Vladimirovich Laikov, Leonid Valentinovich Lopukhov, and Svetlana Frantsevna Khaibullina. "Seasonal changes in serum metabolite and cytokine levels in Multiple Sclerosis." In All-Russian scientific conference with International Participation. Publishing house Sreda, 2022. http://dx.doi.org/10.31483/r-102302.

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Multiple sclerosis (MS) is a chronic debilitating disease of unknown etiology. The disease has a seasonal exacerbation of clinical symptoms, which are frequently described in spring and summer. However, the mechanisms of such seasonal exacerbations remain unknown. In this study, we used targeted metabolomics analysis of serum samples using LC-MC/MC to determine seasonal changes in metabolites. We have found changes in multiple metabolites which differed depending on season. The ceramides, belonging to the sphingolipid pathway, were found activated in spring-summer (SS) and fall-winter (FW) MS, suggesting their central role in disease pathogenesis. Our identification of ceramide activation suggests a mechanism of neuron damage in MS which could be further investigated as therapeutic targets.
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Hanker, Lars, Ahmed El-Balat, Thomas Karn, Uwe Holtrich, Benedikt Decker, Jacobus Pfisterer, Heide Gevensleben, and Stefan Kommoss. "EP222/#606 Acid ceramidase (ASAH1) expression is associated with improved overall survival in patients with high-grade serous ovarian cancer from the ICON-7 trial." In IGCS 2022 Annual Meeting Abstracts. BMJ Publishing Group Ltd, 2022. http://dx.doi.org/10.1136/ijgc-2022-igcs.313.

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Hanker, Lars Christian, Ahemd El-Balat, Thomas Karn, Uwe Holtrich, Bendickt Decker, Jakobus Pfisterer, Heide Gevensleben, and Stefan Kommoss. "2022-RA-906-ESGO Acid ceramidase(ASAH1)expression is associated with improved progression- and overall survival in high-grade serous ovarian cancer patients." In ESGO 2022 Congress. BMJ Publishing Group Ltd, 2022. http://dx.doi.org/10.1136/ijgc-2022-esgo.589.

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Wann, Daniel, Victoria Palau, Janet Lightner, Marianne Brannon, William Stone, and Koyamangalath Krishnan. "Abstract 4639: Metformin decreases cellular ceramides in MCF-7 and MDA-MB 231 breast cancer cell lines by inhibition of ceramide synthetic enzymes." In Proceedings: AACR 106th Annual Meeting 2015; April 18-22, 2015; Philadelphia, PA. American Association for Cancer Research, 2015. http://dx.doi.org/10.1158/1538-7445.am2015-4639.

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Reports on the topic "Ceramidase"

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Beckham, Thomas H. Evaluation of Acid Ceramidase Overexpression-Induced Activation of the Oncogenic Akt Pathway in Prostate Cancer. Fort Belvoir, VA: Defense Technical Information Center, January 2014. http://dx.doi.org/10.21236/ada600484.

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Alonso, Alicia. Ceramidas: no sólo en las cremas de belleza. Sociedad Española de Bioquímica y Biología Molecular (SEBBM), March 2015. http://dx.doi.org/10.18567/sebbmdiv_anc.2015.03.2.

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Momchilova, Albena, Rumiana Tzoneva, Tania Markovska, Mariana Hadzhilazova, Liliana Maslenkova, and Roumen Pankov. Genistein Alters Ceramide Levels in A549 Lung Adenocarcinoma Cells. "Prof. Marin Drinov" Publishing House of Bulgarian Academy of Sciences, July 2020. http://dx.doi.org/10.7546/crabs.2020.07.08.

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Wang, Hongtao, and Myles C. Cabot. Characterization of the Contribution of Ceramide to Chemotherapy Sensitization in Breast Cancer Cells. Fort Belvoir, VA: Defense Technical Information Center, September 2001. http://dx.doi.org/10.21236/ada398144.

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Wang, Hongtao, and Myles C. Cabot. Characterization of the Contribution of Ceramide to Chemotherapy Sensitization in Breast Cancer Cells. Fort Belvoir, VA: Defense Technical Information Center, September 2002. http://dx.doi.org/10.21236/ada410271.

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Hansen, Peter J., and Zvi Roth. Use of Oocyte and Embryo Survival Factors to Enhance Fertility of Heat-stressed Dairy Cattle. United States Department of Agriculture, August 2011. http://dx.doi.org/10.32747/2011.7697105.bard.

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The overall goal was to identify survival factors that can improve pregnancy success following insemination or embryo transfer in lactating dairy cows exposed to heat stress. First, we demonstrated that oocytes are actually damaged by elevated temperature in the summer. Then we tested two thermoprotective molecules for their effect on oocyte damage caused by heat shock. One molecule, ceramide was not thermoprptective. Another, insulin-like growth factor-1 (IGF) reduced the effects of heat shock on oocyte apoptosis and oocyte cleavage when added during maturation. We also used lactating cows exposed to heat stress to determine whether bovine somatotropin (bST), which increases IGF1 levels in vivo, would improve fertility in summer. Cows treated with bST received a single injection at 3 days before insemination. Controls received no additional treatment. Treatment with bST did not significantly increase the proportion of inseminated cows diagnosed pregnant although it was numerically greater for the bST group (24.2% vs 17.8%, 124–132 cows per group). There was a tendency (p =0.10) for a smaller percent of control cows to have high plasma progesterone concentrations (≥ 1 ng/ml) at Day 7 after insemination than for bST-treated cows (72.6 vs 81.1%). When only cows that were successfully synchronized were considered, the magnitude of the absolute difference in the percentage of inseminated cows that were diagnosed pregnant between bST and control cows was reduced (24.8 vs 22.4% pregnant for bST and control). Results failed to indicate a beneficial effect of bST treatment on fertility of lactating dairy cows. In another experiment, we found a tendency for addition of IGF1 to embryo culture medium to improve embryonic survival after embryo transfer when the experiment was done during heat stress but not when the experiment was done in the absence of heat stress. Another molecule tested, granulocyte-macrophage colony-stimulating factor (GM-CSF; also called colony-stimulating factor-2), improved embryonic survival in the absence of heat stress. We also examined whether heat shock affects the sperm cell. There was no effect of heat shock on sperm apoptosis (programmed cell death) or on sperm fertilizing ability. Therefore, effects of heat shock on sperm function after ejaculation if minimal. However, there were seasonal changes in sperm characteristics that indicates that some of the decrease in dairy cow fertility during the summer in Israel is due to using semen of inferior quality. Semen was collected from five representative bulls throughout the summer (August and September) and winter (December and January). There were seasonal differences in ion concentration in seminal plasma and in the mRNA for various ion channels known to be involved in acrosome reactions. Furthermore, the proportion of sperm cells with damaged acrosomes was higher in post-thaw semen collected in the summer than in its counterpart collected in winter (54.2 ± 3.5% vs. 51.4 ± 1.9%, respectively; P < 0.08Further examination is required to determine whether such alterations are involved in the low summer fertility of dairy cows.
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Hansen, Peter J., and Amir Arav. Embryo transfer as a tool for improving fertility of heat-stressed dairy cattle. United States Department of Agriculture, September 2007. http://dx.doi.org/10.32747/2007.7587730.bard.

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The overall objective of the current proposal is to develop procedures to improve the pregnancy rate achieved following transfer of fresh or cryopreserved embryos produced in the laboratory into heat-stress recipients. The overall hypothesis is that pregnancy rate in heat-stressed lactating cows can be improved by use of embryo transfer and that additional gains in pregnancy rate can be achieved through development of procedures to cryopreserve embryos, select embryos most likely to establish and maintain pregnancy after transfer, and to enhance embryo competence for post-transfer survival through manipulation of culture conditions. The original specific objectives were to 1) optimize procedures for cryopreservation (Israel/US), 2) develop procedures for identifying embryos with the greatest potential for development and survival using the remote monitoring system called EmbryoGuard (Israel), 3) perform field trials to test the efficacy of cryopreservation and the EmbryoGuard selection system for improving pregnancy rates in heat-stressed, lactating cows (US/Israel), 4) test whether selection of fresh or frozen-thawed blastocysts based on measurement of group II caspase activity is an effective means of increasing survival after cryopreservation and post-transfer pregnancy rate (US), and 5) identify genes in blastocysts induced by insulin-like growth factor-1 (IGF-1) (US). In addition to these objectives, additional work was carried out to determine additional cellular determinants of embryonic resistance to heat shock. There were several major achievements. Results of one experiment indicated that survival of embryos to freezing could be improved by treating embryos with cytochalasin B to disrupt the cytoskeleton. An additional improvement in the efficacy of embryo transfer for achieving pregnancy in heat-stressed cows follows from the finding that IGF-1 can improve post-transfer survival of in vitro produced embryos in the summer but not winter. Expression of several genes in the blastocyst was regulated by IGF-1 including IGF binding protein-3, desmocollin II, Na/K ATPase, Bax, heat shock protein 70 and IGF-1 receptor. These genes are likely candidates 1) for developing assays for selection of embryos for transfer and 2) as marker genes for improving culture conditions for embryo production. The fact that IGF-1 improved survival of embryos in heat-stressed recipients only is consistent with the hypothesis that IGF-1 confers cellular thermotolerance to bovine embryos. Other experiments confirmed this action of IGF-1. One action of IGF-1, the ability to block heat-shock induced apoptosis, was shown to be mediated through activation of the phosphatidylinositol 3-kinase pathway. Other cellular determinants of resistance of embryos to elevated temperature were identified including redox status of the embryo and the ceramide signaling pathway. Developmental changes in embryonic apoptosis responses in response to heat shock were described and found to include alterations in the capacity of the embryo to undergo caspase-9 and caspase-3 activation as well as events downstream from caspase-3 activation. With the exception of IGF-1, other possible treatments to improve pregnancy rate to embryo transfer were not effective including selection of embryos for caspase activity, treatment of recipients with GnRH.and bilateral transfer of twin embryos. In conclusion, accomplishments achieved during the grant period have resulted in methods for improving post-transfer survival of in vitro produced embryos transferred into heat-stressed cows and have lead to additional avenues for research to increase embryo resistance to elevated temperature and improve survival to cryopreservation. In addition, embryo transfer of vitrified IVF embryos increased significantly the pregnancy rate in repeated breeder cows.
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