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de Lima CB, Milazzotto MP, Vireque AA, Joaquim DC, Sobreira TJP, Ferreira CR. Effect of lipid extraction and room temperature transportation of bovine oocytes determined by MRM profiling. RESEARCH SQUARE 2023:rs.3.rs-3788683. [PMID: 38196623 PMCID: PMC10775384 DOI: 10.21203/rs.3.rs-3788683/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/11/2024]
Abstract
Lipids play many important physiological roles in mammalian reproduction, being essential for the acquisition of oocyte competence and post-fertilization embryonic development. Lipid profiling in samples of minute size, such as oocytes, is challenging but has been achieved by mass spectrometry technologies such as multiple reaction monitoring (MRM) profiling. With the goals of further simplifying sample workflow and investigating the influence of pre-analytical conditions, we have evaluated how different extraction methods and transportation of lipid extracts in vacuum and at room temperature impacted the lipid profile of bovine oocytes. Using a comprehensive method, 316 MRMs associated with lipids of 10 different classes were screened in oocyte lipid extracts prepared by 2 extraction methods (one-step methanol addition or Bligh and Dyer) and transporting them in dry ice or at room temperature inside vacuum packages. No changes in the multivariate analysis (PCA) were noticeable due to transportation temperature, while lipid profiles were more affected by the lipid extraction protocol. Sample extraction using pure methanol favored the detection of phospholipids uniformly, while Bligh and Dyer favored the detection of neutral intracellular lipids. Triacylglycerol lipids and free fatty acids yielded decreased abundances when samples were transported at room temperature. We conclude that if samples are submitted to the same lipid extraction protocol and same transportation batch at room temperature coupled with vacuum conditions it is possible to analyze lipid extracts of bovine oocytes and still obtain informative lipid profiling results.
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Shi T, Li M, Yu Y. Machine learning-enhanced insights into sphingolipid-based prognostication: revealing the immunological landscape and predictive proficiency for immunomotherapy and chemotherapy responses in pancreatic carcinoma. Front Mol Biosci 2023; 10:1284623. [PMID: 38028544 PMCID: PMC10643633 DOI: 10.3389/fmolb.2023.1284623] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2023] [Accepted: 10/17/2023] [Indexed: 12/01/2023] Open
Abstract
Background: With a poor prognosis for affected individuals, pancreatic adenocarcinoma (PAAD) is known as a complicated and diverse illness. Immunocytes have become essential elements in the development of PAAD. Notably, sphingolipid metabolism has a dual function in the development of tumors and the invasion of the immune system. Despite these implications, research on the predictive ability of sphingolipid variables for PAAD prognosis is strikingly lacking, and it is yet unclear how they can affect PAAD immunotherapy and targeted pharmacotherapy. Methods: The investigation process included SPG detection while also being pertinent to the prognosis for PAAD. Both the analytical capability of CIBERSORT and the prognostic capability of the pRRophetic R package were used to evaluate the immunological environments of the various HCC subtypes. In addition, CCK-8 experiments on PAAD cell lines were carried out to confirm the accuracy of drug sensitivity estimates. The results of these trials, which also evaluated cell survival and migratory patterns, confirmed the usefulness of sphingolipid-associated genes (SPGs). Results: As a result of this thorough investigation, 32 SPGs were identified, each of which had a measurable influence on the dynamics of overall survival. This collection of genes served as the conceptual framework for the development of a prognostic model, which was carefully assembled from 10 chosen genes. It should be noted that this grouping of patients into cohorts with high and low risk was a sign of different immune profiles and therapy responses. The increased abundance of SPGs was identified as a possible sign of inadequate responses to immune-based treatment approaches. The careful CCK-8 testing carried out on PAAD cell lines was of the highest importance for providing clear confirmation of drug sensitivity estimates. Conclusion: The significance of Sphingolipid metabolism in the complex web of PAAD development is brought home by this study. The novel risk model, built on the complexity of sphingolipid-associated genes, advances our understanding of PAAD and offers doctors a powerful tool for developing personalised treatment plans that are specifically suited to the unique characteristics of each patient.
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Affiliation(s)
| | | | - Yabin Yu
- Department of Hepatobiliary Surgery, The Affiliated Huaian No 1 People’s Hospital of Nanjing Medical University, Huaian, China
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Mucinski JM, McCaffrey JM, Rector RS, Kasumov T, Parks EJ. Relationship between hepatic and mitochondrial ceramides: A novel in vivo method to track ceramide synthesis. J Lipid Res 2023; 64:100366. [PMID: 37028768 DOI: 10.1016/j.jlr.2023.100366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/14/2022] [Revised: 03/22/2023] [Accepted: 03/24/2023] [Indexed: 04/08/2023] Open
Abstract
Ceramides (CERs) are key intermediate sphingolipids implicated in contributing to mitochondrial dysfunction and the development of multiple metabolic conditions. Despite the growing evidence of CERs role in disease risk, kinetic methods to measure CER turnover are lacking, particularly using in vivo models. The utility of orally-administered 13C3, 15N L-serine, dissolved in drinking water, was tested to quantify CER 18:1/16:0 synthesis in 10 week-old male and female C57Bl/6 mice. To generate isotopic labeling curves, animals consumed either a control (CD) or high fat diet (HFD; n=24/diet) for two weeks and varied in the duration of the consumption of serine-labeled water (0, 1, 2, 4, 7, or 12 days; n=four animals/day/diet). Unlabeled and labeled hepatic and mitochondrial CERs were quantified using liquid chromatography tandem mass spectrometry. Total hepatic CER content did not differ between the two diet groups while total mitochondrial CERs increased with HFD feeding (60%, P<0.001). Within hepatic and mitochondrial pools, HFD induced greater saturated CER concentrations (P<0.05) and significantly elevated absolute turnover of 16:0 mitochondrial CER (mitochondria: 59%, P<0.001 versus liver: 15%, P=0.256). The data suggest cellular redistribution of CERs due to the HFD. These data demonstrate that a two-week HFD alters the turnover and content of mitochondrial CERs. Given the growing data on CERs contributing to hepatic mitochondrial dysfunction and the progression of multiple metabolic diseases, this method may now be used to investigate how CER turnover is altered in these conditions.
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Zhang X, Zhuge J, Liu J, Xia Z, Wang H, Gao Q, Jiang H, Qu Y, Fan L, Ma J, Tan C, Luo W, Luo Y. Prognostic signatures of sphingolipids: Understanding the immune landscape and predictive role in immunotherapy response and outcomes of hepatocellular carcinoma. Front Immunol 2023; 14:1153423. [PMID: 37006285 PMCID: PMC10063861 DOI: 10.3389/fimmu.2023.1153423] [Citation(s) in RCA: 22] [Impact Index Per Article: 22.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2023] [Accepted: 03/06/2023] [Indexed: 03/19/2023] Open
Abstract
Background Hepatocellular carcinoma (HCC) is a complex disease with a poor outlook for patients in advanced stages. Immune cells play an important role in the progression of HCC. The metabolism of sphingolipids functions in both tumor growth and immune infiltration. However, little research has focused on using sphingolipid factors to predict HCC prognosis. This study aimed to identify the key sphingolipids genes (SPGs) in HCC and develop a reliable prognostic model based on these genes. Methods The TCGA, GEO, and ICGC datasets were grouped using SPGs obtained from the InnateDB portal. A prognostic gene signature was created by applying LASSO-Cox analysis and evaluating it with Cox regression. The validity of the signature was verified using ICGC and GEO datasets. The tumor microenvironment (TME) was examined using ESTIMATE and CIBERSORT, and potential therapeutic targets were identified through machine learning. Single-cell sequencing was used to examine the distribution of signature genes in cells within the TME. Cell viability and migration were tested to confirm the role of the key SPGs. Results We identified 28 SPGs that have an impact on survival. Using clinicopathological features and 6 genes, we developed a nomogram for HCC. The high- and low-risk groups were found to have distinct immune characteristics and response to drugs. Unlike CD8 T cells, M0 and M2 macrophages were found to be highly infiltrated in the TME of the high-risk subgroup. High levels of SPGs were found to be a good indicator of response to immunotherapy. In cell function experiments, SMPD2 and CSTA were found to enhance survival and migration of Huh7 cells, while silencing these genes increased the sensitivity of Huh7 cells to lapatinib. Conclusion The study presents a six-gene signature and a nomogram that can aid clinicians in choosing personalized treatments for HCC patients. Furthermore, it uncovers the connection between sphingolipid-related genes and the immune microenvironment, offering a novel approach for immunotherapy. By focusing on crucial sphingolipid genes like SMPD2 and CSTA, the efficacy of anti-tumor therapy can be increased in HCC cells.
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Affiliation(s)
- Xin Zhang
- Department of Pathology, the Second People’s Hospital of Foshan, Affiliated Foshan Hospital of Southern Medical University, Foshan, China
| | - Jinke Zhuge
- Department of Respiratory Medicine, Hainan Cancer Hospital, Hainan, China
| | - Jinhui Liu
- Department of Gynecology, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Zhijia Xia
- Department of General, Visceral, and Transplant Surgery, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Huixiong Wang
- Department of Hepatobiliary Surgery, Hospital of Inner Mongolia Baotou Steel, Baotou, Inner Mongolia, China
| | - Qiang Gao
- Department of Hepatobiliary Surgery, The First Affiliated Hospital of Guangxi Medical University, Nanning, China
| | - Hao Jiang
- Department of Pathology, the Second People’s Hospital of Foshan, Affiliated Foshan Hospital of Southern Medical University, Foshan, China
| | - Yanyu Qu
- Department of Pathology, the Second People’s Hospital of Foshan, Affiliated Foshan Hospital of Southern Medical University, Foshan, China
| | - Linlin Fan
- Department of Pathology, the Second People’s Hospital of Foshan, Affiliated Foshan Hospital of Southern Medical University, Foshan, China
| | - Jiali Ma
- Department of Pathology, the Second People’s Hospital of Foshan, Affiliated Foshan Hospital of Southern Medical University, Foshan, China
| | - Chunhua Tan
- Department of Pathology, the Second People’s Hospital of Foshan, Affiliated Foshan Hospital of Southern Medical University, Foshan, China
| | - Wei Luo
- Department of General Surgery, The Affiliated Traditional Chinese Medicine Hospital of Southwest Medical University, Luzhou, China
| | - Yong Luo
- Department of Urology, The Second People’s Hospital of Foshan, Affiliated Foshan Hospital of Southern Medical University, Foshan, China
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Zhang P, Pei S, Gong Z, Feng Y, Zhang X, Yang F, Wang W. By integrating single-cell RNA-seq and bulk RNA-seq in sphingolipid metabolism, CACYBP was identified as a potential therapeutic target in lung adenocarcinoma. Front Immunol 2023; 14:1115272. [PMID: 36776843 PMCID: PMC9914178 DOI: 10.3389/fimmu.2023.1115272] [Citation(s) in RCA: 25] [Impact Index Per Article: 25.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2022] [Accepted: 01/12/2023] [Indexed: 01/28/2023] Open
Abstract
Background Lung adenocarcinoma (LUAD) is a heterogeneous disease with a dismal prognosis for advanced tumors. Immune-associated cells in the microenvironment substantially impact LUAD formation and progression, which has gained increased attention in recent decades. Sphingolipids have a profound impact on tumor formation and immune infiltration. However, few researchers have focused on the utilization of sphingolipid variables in the prediction of LUAD prognosis. The goal of this work was to identify the major sphingolipid-related genes (SRGs) in LUAD and develop a valid prognostic model based on SRGs. Methods The most significant genes for sphingolipid metabolism (SM) were identified using the AUCell and WGCNA algorithms in conjunction with single-cell and bulk RNA-seq. LASSO and COX regression analysis was used to develop risk models, and patients were divided into high-and low-risk categories. External nine provided cohorts evaluated the correctness of the models. Differences in immune infiltration, mutation landscape, pathway enrichment, immune checkpoint expression, and immunotherapy were also further investigated in distinct subgroups. Finally, cell function assay was used to verify the role of CACYBP in LUAD cells. Results A total of 334 genes were selected as being most linked with SM activity for further investigation, and a risk model consisting of 11 genes was established using lasso and cox regression. According to the median risk value, patients were split into high- and low-risk groups, and the high-risk group had a worse prognosis. The low-risk group had more immune cell infiltration and higher expression of immune checkpoints, which illustrated that the low-risk group was more likely to benefit from immunotherapy. It was verified that CACYBP could increase the ability of LUAD cells to proliferate, invade, and migrate. Conclusion The eleven-gene signature identified in this research may help physicians create individualized care plans for LUAD patients. CACYBP may be a new therapeutic target for patients with advanced LUAD.
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Affiliation(s)
- Pengpeng Zhang
- Department of Thoracic Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Shengbin Pei
- Department of Breast Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Zeitian Gong
- Department of Thoracic Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Yanlong Feng
- Department of Thoracic Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Xiao Zhang
- Department of Thoracic Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China
| | - Fang Yang
- Department of Ophthalmology, Charité – Universitätsmedizin Berlin, Campus Virchow-Klinikum, Berlin, Germany,*Correspondence: Fang Yang, ; Wei Wang,
| | - Wei Wang
- Department of Thoracic Surgery, The First Affiliated Hospital of Nanjing Medical University, Nanjing, China,*Correspondence: Fang Yang, ; Wei Wang,
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Sun Y, Xu Y, Che X, Wu G. Development of a Novel Sphingolipid Signaling Pathway-Related Risk Assessment Model to Predict Prognosis in Kidney Renal Clear Cell Carcinoma. Front Cell Dev Biol 2022; 10:881490. [PMID: 35846357 PMCID: PMC9277577 DOI: 10.3389/fcell.2022.881490] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/23/2022] [Accepted: 06/03/2022] [Indexed: 11/13/2022] Open
Abstract
This study aimed to explore underlying mechanisms by which sphingolipid-related genes play a role in kidney renal clear cell carcinoma (KIRC) and construct a new prognosis-related risk model. We used a variety of bioinformatics methods and databases to complete our exploration. Based on the TCGA database, we used multiple R-based extension packages for data transformation, processing, and statistical analyses. First, on analyzing the CNV, SNV, and mRNA expression of 29 sphingolipid-related genes in various types of cancers, we found that the vast majority were protective in KIRC. Subsequently, we performed cluster analysis of patients with KIRC using sphingolipid-related genes and successfully classified them into the following three clusters with significant prognostic differences: Cluster 1, Cluster 2, and Cluster 3. We performed differential analyses of transcription factor activity, drug sensitivity, immune cell infiltration, and classical oncogenes to elucidate the unique roles of sphingolipid-related genes in cancer, especially KIRC, and provide a reference for clinical treatment. After analyzing the risk rates of sphingolipid-related genes in KIRC, we successfully established a risk model composed of seven genes using LASSO regression analysis, including SPHK1, CERS5, PLPP1, SGMS1, SGMS2, SERINC1, and KDSR. Previous studies have suggested that these genes play important biological roles in sphingolipid metabolism. ROC curve analysis results showed that the risk model provided good prediction accuracy. Based on this risk model, we successfully classified patients with KIRC into high- and low-risk groups with significant prognostic differences. In addition, we performed correlation analyses combined with clinicopathological data and found a significant correlation between the risk model and patient’s M, T, stage, grade, and fustat. Finally, we developed a nomogram that predicted the 5-, 7-, and 10-year survival in patients with KIRC. The model we constructed had strong predictive ability. In conclusion, we believe that this study provides valuable data and clues for future studies on sphingolipid-related genes in KIRC.
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Affiliation(s)
- Yonghao Sun
- Department of Urology, The First Affiliated Hospital of Dalian Medical University, Dalian, China
| | - Yingkun Xu
- Department of Endocrine and Breast Surgery, The First Affiliated Hospital of Chongqing Medical University, Chongqing, China
| | - Xiangyu Che
- Department of Urology, The First Affiliated Hospital of Dalian Medical University, Dalian, China
- *Correspondence: Guangzhen Wu, ; Xiangyu Che,
| | - Guangzhen Wu
- Department of Urology, The First Affiliated Hospital of Dalian Medical University, Dalian, China
- *Correspondence: Guangzhen Wu, ; Xiangyu Che,
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Zhang R, Zhu Z, Jia W. Time-Series Lipidomics Insights into the Progressive Characteristics of Lipid Constituents of Fresh Walnut during Postharvest Storage. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2021; 69:13796-13809. [PMID: 34763422 DOI: 10.1021/acs.jafc.1c05120] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/13/2023]
Abstract
A high-throughput lipid profiling platform adopting an accurate quantification strategy was built based on Q-Orbitrap mass spectrometry. Lipid components of fresh walnut during postharvest storage were determined, and the fatty acid distributions in triacylglycerol and polar lipids were also characterized. A total of 554 individual lipids in fresh walnut were mainly glycerolipids (56.7%), glycerophospholipids (32.4%), and sphingolipids (11%). With the progress of postharvest storage, 16 lipid subclasses in the stored walnut sample were significantly degraded, in which 34 lipids changed significantly between the fresh and stored groups. The sphingolipid metabolism, glycerolipid metabolism, and linoleic acid metabolism pathways were significantly enriched. The oxidation and degradation mechanism of linoleic acid in walnut kernel during postharvest storage was proposed. The established lipidomics platform can supply reliable and traceable lipid profiling data, help to improve the understanding of lipid degradation in fresh walnut, and offer a framework for analyzing lipid metabolisms in other tree nuts.
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Affiliation(s)
- Rong Zhang
- School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China
| | - Zhenbao Zhu
- School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China
| | - Wei Jia
- School of Food and Biological Engineering, Shaanxi University of Science & Technology, Xi'an 710021, China
- Shaanxi Research Institute of Agricultural Products Processing Technology, Xi'an 710021, China
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Barron K, Ogretmen B, Krupenko N. Ceramide synthase 6 mediates sex-specific metabolic response to dietary folic acid in mice. J Nutr Biochem 2021; 98:108832. [PMID: 34358645 DOI: 10.1016/j.jnutbio.2021.108832] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Revised: 05/20/2021] [Accepted: 07/01/2021] [Indexed: 11/26/2022]
Abstract
Folic acid-fortified foods and multi-vitamin supplements containing folic acid (FA) are widely used around the world, but the exact mechanisms/metabolic effects of FA are not precisely identified. We have demonstrated that Ceramide Synthase 6 (CerS6) and C16:0-ceramide mediate response to folate stress in cultured cells. Here we investigated the dietary FA effects on mouse liver metabolome, with a specific focus on sphingolipids, CerS6 and C16:0-ceramide. Wild-type and CerS6-/- mice were fed FA-deficient, control, or FA over-supplemented diets for 4 weeks. After dietary treatment, liver concentrations of ceramides, sphingomyelins and hexosylceramides were measured by LC-MS/MS and complemented by untargeted metabolomic characterization of mouse livers. Our study shows that alterations in dietary FA elicit multiple sphingolipid responses mediated by CerS6 in mouse livers. Folic acid-deficient diet elevated C14:0-, C18:0- and C20:0- but not C16:0-ceramide in WT male and female mice. Additionally, FA over-supplementation increased multiple sphingomyelin species, including total sphingomyelins, in both sexes. Of note, concentrations of C14:0- and C16:0-ceramides and hexosylceramides were significantly higher in female livers than in male. The latter were increased by FD diet, with no difference between sexes in total pools of these sphingolipid classes. Untargeted liver metabolomic analysis concurred with the targeted measurements and showed broad effects of dietary FA and CerS6 status on multiple lipid classes including sex-specific effects on phosphatidylethanolamines and diacylglycerols. Our study demonstrates that both dietary FA and CerS6 status exhibit pleiotropic and sex-dependent effects on liver metabolism, including hepatic sphingolipids, diacylglycerols, long chain fatty acids, and phospholipids.
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Affiliation(s)
- Keri Barron
- Nutrition Research Institute, University of North Carolina at Chapel Hill, Kannapolis, North Carolina
| | - Besim Ogretmen
- Department of Biochemistry & Molecular Biology, Hollings Cancer center, Medical University of South Carolina, 173 Ashley Avenue, Charleston, South Carolina
| | - Natalia Krupenko
- Nutrition Research Institute, University of North Carolina at Chapel Hill, Kannapolis, North Carolina,; Department of Nutrition, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina,.
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Zhao D, Hajiaghamohseni LM, Liu X, Szulc ZM, Bai A, Bielawska A, Norris JS, Reddy SV, Hannun YA, Haque A. Inhibition of acid ceramidase regulates MHC class II antigen presentation and suppression of autoimmune arthritis. Cytokine 2020; 135:155219. [PMID: 32738771 DOI: 10.1016/j.cyto.2020.155219] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 07/04/2020] [Accepted: 07/20/2020] [Indexed: 12/30/2022]
Abstract
The bioactive sphingolipid ceramide affects immune responses although its effect on antigen (Ag) processing and delivery by HLA class II to CD4+T-cells remains unclear. Therefore, we examined the actions of a novel cell-permeable acid ceramidase (AC) inhibitor [(1R,2R) N myristoylamino-(4'-nitrophenyl)-propandiol-1,3] on antigen presentation and inflammatory cytokine production by Ag-presenting cells (APCs) such as B-cells, macrophages, and dendritic cells. We found that AC inhibition in APCs perturbed Ag-processing and presentation via HLA-DR4 (MHC class II) proteins as measured by coculture assay and T-cell production of IL-2. Mass spectral analyses showed that B13 treatment significantly raised levels of four types of ceramides in human B-cells. B13 treatment did not alter Ag internalization and class II protein expression, but significantly inhibited lysosomal cysteinyl cathepsins (B, S and L) and thiol-reductase (GILT), HLA class II Ag-processing, and generation of functional class II-peptide complexes. Ex vivo Ag presentation assays showed that inhibition of AC impaired primary and recall CD4+T-cell responses and cytokine production in response against type II collagen. Further, B13 delayed onset and reduced severity of inflamed joints and cytokine production in the collagen-induced arthritis mouse model in vivo. These findings suggest that inhibition of AC in APCs may dysregulate endolysosomal proteases and HLA class II-associated self-antigen presentation to CD4+T-cells, attenuating inflammatory cytokine production and suppressing host autoimmune responses.
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Affiliation(s)
- Dan Zhao
- Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States; Darby Children's Research Institute, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States; Hollings Cancer Center, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States
| | - Laela M Hajiaghamohseni
- Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States; Darby Children's Research Institute, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States; Hollings Cancer Center, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States
| | - Xiang Liu
- Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States; Hollings Cancer Center, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States
| | - Zdzislaw M Szulc
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States
| | - Aiping Bai
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States
| | - Alicja Bielawska
- Department of Biochemistry and Molecular Biology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States
| | - James S Norris
- Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States; Darby Children's Research Institute, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States; Hollings Cancer Center, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States
| | - Sakamuri V Reddy
- Darby Children's Research Institute, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States
| | - Yusuf A Hannun
- Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States
| | - Azizul Haque
- Department of Microbiology and Immunology, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States; Darby Children's Research Institute, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States; Hollings Cancer Center, Medical University of South Carolina, 173 Ashley Avenue, Charleston, SC 29425, United States.
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Wigger D, Gulbins E, Kleuser B, Schumacher F. Monitoring the Sphingolipid de novo Synthesis by Stable-Isotope Labeling and Liquid Chromatography-Mass Spectrometry. Front Cell Dev Biol 2019; 7:210. [PMID: 31632963 PMCID: PMC6779703 DOI: 10.3389/fcell.2019.00210] [Citation(s) in RCA: 28] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/27/2019] [Accepted: 09/11/2019] [Indexed: 12/11/2022] Open
Abstract
Sphingolipids are a class of lipids that share a sphingoid base backbone. They exert various effects in eukaryotes, ranging from structural roles in plasma membranes to cellular signaling. De novo sphingolipid synthesis takes place in the endoplasmic reticulum (ER), where the condensation of the activated C16 fatty acid palmitoyl-CoA and the amino acid L-serine is catalyzed by serine palmitoyltransferase (SPT). The product, 3-ketosphinganine, is then converted into more complex sphingolipids by additional ER-bound enzymes, resulting in the formation of ceramides. Since sphingolipid homeostasis is crucial to numerous cellular functions, improved assessment of sphingolipid metabolism will be key to better understanding several human diseases. To date, no assay exists capable of monitoring de novo synthesis sphingolipid in its entirety. Here, we have established a cell-free assay utilizing rat liver microsomes containing all the enzymes necessary for bottom-up synthesis of ceramides. Following lipid extraction, we were able to track the different intermediates of the sphingolipid metabolism pathway, namely 3-ketosphinganine, sphinganine, dihydroceramide, and ceramide. This was achieved by chromatographic separation of sphingolipid metabolites followed by detection of their accurate mass and characteristic fragmentations through high-resolution mass spectrometry and tandem-mass spectrometry. We were able to distinguish, unequivocally, between de novo synthesized sphingolipids and intrinsic species, inevitably present in the microsome preparations, through the addition of stable isotope-labeled palmitate-d3 and L-serine-d3. To the best of our knowledge, this is the first demonstration of a method monitoring the entirety of ER-associated sphingolipid biosynthesis. Proof-of-concept data was provided by modulating the levels of supplied cofactors (e.g., NADPH) or the addition of specific enzyme inhibitors (e.g., fumonisin B1). The presented microsomal assay may serve as a useful tool for monitoring alterations in sphingolipid de novo synthesis in cells or tissues. Additionally, our methodology may be used for metabolism studies of atypical substrates - naturally occurring or chemically tailored - as well as novel inhibitors of enzymes involved in sphingolipid de novo synthesis.
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Affiliation(s)
- Dominik Wigger
- Department of Toxicology, University of Potsdam, Nuthetal, Germany
| | - Erich Gulbins
- Department of Molecular Biology, University of Duisburg-Essen, Essen, Germany.,Department of Surgery, University of Cincinnati, Cincinnati, OH, United States
| | - Burkhard Kleuser
- Department of Toxicology, University of Potsdam, Nuthetal, Germany
| | - Fabian Schumacher
- Department of Toxicology, University of Potsdam, Nuthetal, Germany.,Department of Molecular Biology, University of Duisburg-Essen, Essen, Germany
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