Pyne, N. J. & Pyne, S. Selectivity and specificity of sphingosine 1-phosphate receptor ligands: “off-targets” or complex pharmacology?. Front. Pharmacol. 2, 26. https://doi.org/10.3389/fphar.2011.00026 (2011). Using an internal standard approach, 58 sphingolipid species were identified based on accurate mass and retention time, with the majority of sphingolipids detected with excellent precision (RSD < 10%). Quantitation was performed by semi-automated peak integration using Tracefinder 3.2 (Thermo Fisher) with manual verification. The sample concentrations were calculated based on the ratio of peak area of each identified lipid component over the area of the corresponding internal standard (C17 ceramide was used as internal standard for all ceramides). Concentrations were then converted to pmol/1 × 10 6 cells by dividing calculated concentration by cell number. For simplicity of nomenclature, ceramides with no double bonds were defined as dihydroceramides, those with one double bond defined as ceramides, and those with two double bonds defined as ceramides with unsaturated N-linked acyl chains (noting that the latter two classes may contain small contributions from isomeric dihydroceramides with unsaturated N-linked acyl chains). Sphingosine kinase assays The standard was developed by counter fraud experts (including from across the public and private sectors, banking and academia) to help guide a whole of government approach. It has been extensively tested in government before its formal release, and represents the minimum that all public bodies are expected to have in place. For the non-adherent MV411 cells, Des1 assays were performed as previously described 24. For assays using adherent HEK293T, the cells were harvested by trypsin and counted prior to use in the assay. Briefly, intact cells (at 1 × 10 6 cells/mL) were labeled with NBD-C6-dhCer (5 µM) in serum-free media and incubated on ice for 30 min. Cells were then pelleted and washed into fresh media (with 0.5% FBS) and dispensed into 24-well plates containing inhibitor/vehicle treatments (400 µL total) and incubated for 2 h at 37 °C and 5% CO 2. The cells were then harvested and pelleted via centrifugation at 500× g and resuspended in 100 µL H 2O. The samples were sonicated for 30 s in a bath sonicator (Diagenode) followed by the addition of 900µL cold methanol. Immediately before analysis, the samples were centrifuged for 3 min at 17,000× g and transferred to glass HPLC vials (Phenomenex). Samples (50 μL) were analysed on a Waters HPLC coupled to a fluorescence detector using a 30 cm C18 reverse-phase column (Phenomonex) eluted with 1 mL/min 20% H 2O and 80% acetonitrile with 0.1% trifluoroacetic acid. NBD-labelled substrate and product were quantitated with excitation and emission wavelengths of 465 nm and 530 nm, respectively. Des1 inhibition was calculated relative to vehicle as percentage peak area under the curve. Des1 assays using cell lysates

Stepanovska, B. & Huwiler, A. Targeting the S1P receptor signaling pathways as a promising approach for treatment of autoimmune and inflammatory diseases. Pharmacol. Res. 154, 104170. https://doi.org/10.1016/j.phrs.2019.02.009 (2020). Purified Des1-FLAG protein was assayed with NBD-C6-dhCer in 1% fatty acid-free BSA, 1 mM NADPH, 50 µM (NH 4) 2Fe(SO 4) 2 (prepared with 3 × molar excess ascorbic acid) and recombinant cytochrome B5 (CYB5) in 50 mM Tris–HCl buffer (pH 7.2) with 1 mM DTT. The reaction was incubated at 37 °C for 30 min, and then terminated by the addition of methanol and centrifugation at 17,000× g for 5 min. Lipid extracts were transferred to glass HPLC vials and analysed as above. S1P lyase assay Kang, J., Lee, J. H. & Im, D. S. Topical application of S1P2 antagonist JTE-013 attenuates 2,4-dinitrochlorobenzene-induced atopic dermatitis in mice. Biomol. Ther. 28, 537–541. https://doi.org/10.4062/biomolther.2020.036 (2020).Salomone, S. & Waeber, C. Selectivity and specificity of sphingosine-1-phosphate receptor ligands: Caveats and critical thinking in characterizing receptor-mediated effects. Front. Pharmacol. 2, 9. https://doi.org/10.3389/fphar.2011.00009 (2011). Ogretmen, B. Sphingolipid metabolism in cancer signalling and therapy. Nat. Rev. Cancer 18, 33–50. https://doi.org/10.1038/nrc.2017.96 (2018). Human S1P lyase cDNA (SGPL1, Genbank Accession number NM_003901) was amplified from placenta cDNA and FLAG epitope-tagged at the 3′ end by PCR with oligonucleotide primers 5′-TATATAGAATTCGCCACCATGCCTAGCACAGACCTTCT-3′ and 5′-TATATAGAATTCACTTGTCATCGTCGTCCTTGTAGTCGTGGGGTTTTGGAGAACCAT-3′. The PCR product was digested with EcoRI and cloned into pcDNA3 (Invitrogen) for expression in mammalian cells. Sequencing verified the orientation and integrity of the cDNA. Quantitative RT-PCR Green, C. D., Maceyka, M., Cowart, L. A. & Spiegel, S. Sphingolipids in metabolic disease: The good, the bad, and the unknown. Cell Metab. 33, 1293–1306. https://doi.org/10.1016/j.cmet.2021.06.006 (2021). Chew, W. S., Wang, W. & Herr, D. R. To fingolimod and beyond: The rich pipeline of drug candidates that target S1P signaling. Pharmacol. Res. 113, 521–532. https://doi.org/10.1016/j.phrs.2016.09.025 (2016).

Salomone, S. et al. Analysis of sphingosine 1-phosphate receptors involved in constriction of isolated cerebral arteries with receptor null mice and pharmacological tools. Br. J. Pharmacol. 153, 140–147. https://doi.org/10.1038/sj.bjp.0707581 (2008). Drexler, Y., Molina, J., Mitrofanova, A., Fornoni, A. & Merscher, S. Sphingosine-1-phosphate metabolism and signaling in kidney diseases. J. Am. Soc. Nephrol. 32, 9–31. https://doi.org/10.1681/ASN.2020050697 (2021).

The publication of the Counter Fraud Functional Standard reinforces the government’s commitment to fighting fraud. By meeting the requirements of this standard, public bodies are better prepared, and more able to respond to the risk of fraud against the public sector. Price, S. T. et al. Sphingosine 1-phosphate receptor 2 regulates the migration, proliferation, and differentiation of mesenchymal stem cells. Int. J. Stem Cell Res. Ther. 2, 014. https://doi.org/10.23937/2469-570x/1410014 (2015). Analysis of HEK293T gene expression of S1PR1-5 was performed by quantitative reverse transcriptase PCR (qPCR) as previously described 13 using 5 × 10 6 HEK293T cells. Expression of the S1PR1-5 was analysed using the Rotor-Gene Q Series software (Qiagen) using the comparative quantitation method with HEK293T amplified S1PR1 used as the calibrator. Gene expression of S1PR2 in control and S1P 2 shRNA MV411 cell lines was analysed as above, normalized to GADPH and analysed using the Rotor-Gene Q Series software (Qiagen) using the comparative quantitation method with MV411 amplified S1PR2 used as the calibrator. Intact cell assay for Des1 activity Custodia, A. et al. Ceramide metabolism and Parkinson’s disease-therapeutic targets. Biomolecules https://doi.org/10.3390/biom11070945 (2021).