Quantitative targeted measurements of sphingolipids in Th17 cells before and after the triple knockdown of SPTLC1,2,3 genes (SPT, de novo pathway: sphingolipid metabolism) (part-III)
Project description:Sphingolipids are a highly diverse category of bioactive compounds. This article describes methods that have been validated for the extraction, liquid chromatographic (LC) separation, identification and quantitation of sphingolipids by electrospray ionization, tandem mass spectrometry (ESI-MS/MS) using triple quadrupole (QQQ, API 3000) and quadrupole-linear-ion trap (API 4000 QTrap, operating in QQQ mode) mass spectrometers. Advantages of the QTrap included: greater sensitivity, similar ionization efficiencies for sphingolipids with ceramide versus dihydroceramide backbones, and the ability to identify the ceramide backbone of sphingomyelins using a pseudo-MS3 protocol. Compounds that can be readily quantified using an internal standard cocktail developed by the LIPID MAPS Consortium are: sphingoid bases and sphingoid base 1-phosphates, more complex species such as ceramides, ceramide 1-phosphates, sphingomyelins, mono- and di-hexosylceramides, and these complex sphingolipids with dihydroceramide backbones. With minor modifications, glucosylceramides and galactosylceramides can be distinguished, and more complex species such as sulfatides can also be quantified, when the internal standards are available. LC ESI-MS/MS can be utilized to quantify a large number of structural and signaling sphingolipids using commercially available internal standards. The application of these methods is illustrated with RAW264.7 cells, a mouse macrophage cell line. These methods should be useful for a wide range of focused (sphingo)lipidomic investigations.
Project description:RNA interference is a powerful experimental tool for RNA knockdown, but not all organisms are amenable. Here, we provide a proof of principle demonstration that a type III Csm effector complex can be used for programmable mRNA transcript degradation in eukaryotes. In zebrafish, Streptococcus thermophilus Csm complex (StCsm) proved effective for knockdown of maternally expressed EGFP in germ cells of Tg(ddx4:ddx4-EGFP) fish. It also led to significant, albeit less drastic, fluorescence reduction at one day postfertilization in Tg(myl7:GFP) and Tg(fli1:EGFP) fish that express EGFP zygotically. StCsm targeted against the endogenous tdgf1 elicited the characteristic one-eyed phenotype with greater than 50% penetrance, and hence with similar efficiency to morpholino-mediated knockdown. We conclude that Csm-mediated knockdown is very efficient for maternal transcripts and can also be used for mixed maternal/early zygotic and early zygotic transcripts, in some cases reaching comparable efficiency to morpholino-based knockdown without significant off-target effects.
Project description:rs07-05_sphingolipids-cold - sphingo-1 - The cold choc response seems to be partly triggered by Sphingolipid species. To date no gene response as been associated to sphingolipid signaling pathway in plant. Our aim is to identify among the cold induced genes the ones regulated by sphingolipids and to try to define a sphingolipid pathway specific group of genes. - 7ml of 5 days-old cells suspensions were incubated in presence of different sphingolipid pathway inhibitors, 30 min to 2 hours depending in the coumpound (all were resuspended in DMSO and control were done with DMSO). Then a 30 min cold choc was applied before cells were harvested and frozen in cold nitrogen. RNA were then extracted. FB1 and DMS were from Alexis , Myr from Cayman, TSP from matreya. 6 dye-swap - treated vs untreated comparison
Project description:Sphingolipids (SPLs) are finely tuned structural compounds and bioactive molecules involved in membrane fluidity and cellular homeostasis. The core sphingolipid, ceramide (CER), and its derivatives, regulate several crucial processes in neuronal cells, among them cell differentiation, cell-cell interactions, membrane conductance, synaptic transmission, and apoptosis. Mutations in Ceramide Kinase-Like (CERKL) cause autosomal recessive Retinitis Pigmentosa and Cone Rod Dystrophy. The presence of a conserved lipid kinase domain and the overall similarity with CERK suggested that CERKL might play a role in the SPL metabolism as a CER kinase. Unfortunately, CERKL function and substrate(s), as well as its contribution to the retinal etiopathology, remain as yet unknown. In this work we aimed to characterize the mouse retinal sphingolipidome by UPLC-TOF to first, thoroughly investigate the SPL composition of the murine retina, compare it to our Cerkl -/- model, and finally assess new possible CERKL substrates by phosphorus quantification and protein-lipid overlay. Our results showed a consistent and notable decrease of the retinal SPL content (mainly ranging from 30% to 60%) in the Cerkl -/- compared to WT retinas, which was particularly evident in the glucosyl/galactosyl ceramide species (Glc/GalCer) whereas the phospholipids and neutral lipids remained unaltered. Moreover, evidence in favor of CERKL binding to GlcCer, GalCer and sphingomyelin has been gathered. Altogether, these results highlight the involvement of CERKL in the SPL metabolism, question its role as a kinase, and open new scenarios concerning its function.
Project description:rs07-05_sphingolipids-cold - sphingo-1 - The cold choc response seems to be partly triggered by Sphingolipid species. To date no gene response as been associated to sphingolipid signaling pathway in plant. Our aim is to identify among the cold induced genes the ones regulated by sphingolipids and to try to define a sphingolipid pathway specific group of genes. - 7ml of 5 days-old cells suspensions were incubated in presence of different sphingolipid pathway inhibitors, 30 min to 2 hours depending in the coumpound (all were resuspended in DMSO and control were done with DMSO). Then a 30 min cold choc was applied before cells were harvested and frozen in cold nitrogen. RNA were then extracted. FB1 and DMS were from Alexis , Myr from Cayman, TSP from matreya.
Project description:Mammalian ceramide synthases 1 to 6 (CerS1-6) generate Cer in an acyl-CoA-dependent manner, and expression of individual CerS has been shown to enhance the synthesis of ceramides with particular acyl chain lengths. However, the contribution of each CerS to steady-state levels of specific Cer species has not been evaluated. We investigated the knockdown of individual CerS in the MCF-7 human breast adenocarcinoma cell line by using small-interfering RNA (siRNA). We found that siRNA-induced downregulation of each CerS resulted in counter-regulation of nontargeted CerS. Additionally, each CerS knockdown produced unique effects on the levels of multiple sphingolipid species. For example, downregulation of CerS2 decreased very long-chain Cer but increased levels of CerS4, CerS5, and CerS6 expression and upregulated long-chain and medium-long-chain sphingolipids. Conversely, CerS6 knockdown decreased C16:0-Cer but increased CerS5 expression and caused non-C16:0 sphingolipids to be upregulated. Knockdown of individual CerS failed to decrease total sphingolipids or upregulate sphingoid bases. Treatment with siRNAs targeting combined CerS, CerS2, CerS5, and CerS6, did not change overall Cer or sphingomyelin mass but caused upregulation of dihydroceramide and hexosyl-ceramide and promoted endoplasmic reticulum stress. These data suggest that sphingolipid metabolism is robustly regulated by both redundancy in CerS-mediated Cer synthesis and counter-regulation of CerS expression.
Project description:Triple negative breast cancer (TNBC) patients not attaining pathological Complete Response (pCR) after neo-adjuvant chemotherapy (NAC) have poor prognosis. We characterized 19 patients for somatic mutations in primary tumor biopsy and residual disease (RD) at surgery by 409 cancer-related gene sequencing (IonAmpliSeqTM Comprehensive Cancer Panel). A median of four (range 1-66) genes was mutated in each primary tumor biopsy, and the most common mutated gene was TP53 followed by a long tail of low frequency mutations. There were no recurrent mutations significantly associated with pCR. However, half of patients with RD had primary tumor biopsy with mutations in genes related to the immune system compared with none of those achieving pCR. Overall, the number of mutations showed a downward trend in post- as compared to pre-NAC samples. PIK3CA was the most common altered gene after NAC. The mutational profile of TNBC during treatment as inferred from patterns of mutant allele frequencies in matched pre-and post-NAC samples showed that RD harbored alterations of cell cycle progression, PI3K/Akt/mTOR, and EGFR tyrosine kinase inhibitor-resistance pathways. Our findings support the use of targeted-gene sequencing for TNBC therapeutic development, as patients without pCR may present mutations of immune-related pathways in their primary tumor biopsy, or actionable targets in the RD.
Project description:Lipidomics, the mass spectrometry-based comprehensive analysis of lipids, has attracted attention as an analytical approach to provide novel insight into lipid metabolism and to search for biomarkers. However, an ideal method for both comprehensive and quantitative analysis of lipids has not been fully developed. Here, we have proposed a practical methodology for widely targeted quantitative lipidome analysis using supercritical fluid chromatography fast-scanning triple-quadrupole mass spectrometry (SFC/QqQMS) and theoretically calculated a comprehensive lipid multiple reaction monitoring (MRM) library. Lipid classes can be separated by SFC with a normal-phase diethylamine-bonded silica column with high resolution, high throughput, and good repeatability. Structural isomers of phospholipids can be monitored by mass spectrometric separation with fatty acyl-based MRM transitions. SFC/QqQMS analysis with an internal standard-dilution method offers quantitative information for both lipid class and individual lipid molecular species in the same lipid class. Additionally, data acquired using this method has advantages, including reduction of misidentification and acceleration of data analysis. Using the SFC/QqQMS system, alteration of plasma lipid levels in myocardial infarction-prone rabbits to the supplementation of EPA was first observed. Our developed SFC/QqQMS method represents a potentially useful tool for in-depth studies focused on complex lipid metabolism and biomarker discovery.-Takeda, H., Y. Izumi, M. Takahashi, T. Paxton, S. Tamura, T. Koike, Y. Yu, N. Kato, K. Nagase, M. Shiomi, and T. Bamba.