Deficiency of glucocerebrosidase (GBA), a lysosomal beta-glucosidase, causes Gaucher disease. The enzyme hydrolyzes beta-glucosidic substrates and transglucosylates cholesterol to cholesterol-p... Show moreDeficiency of glucocerebrosidase (GBA), a lysosomal beta-glucosidase, causes Gaucher disease. The enzyme hydrolyzes beta-glucosidic substrates and transglucosylates cholesterol to cholesterol-p-glucoside. Here we show that recombinant human GBA also cleaves beta-xylosides and transxylosylates cholesterol. The xylosyl-cholesterol formed acts as an acceptor for the subsequent formation of di-xylosyl-cholesterol. Common mutant forms of GBA from patients with Gaucher disease with reduced beta-glucosidase activity were similarly impaired in beta-xylosidase, transglucosidase, and transxylosidase activities, except for a slightly reduced xylosidase/glucosidase activity ratio of N370S GBA and a slightly reduced transglucosylation/glucosidase activity ratio of D409H GBA. XylChol was found to be reduced in spleen from patients with Gaucher disease. The origin of newly identified XylChol in mouse and human tissues was investigated. Cultured human cells exposed to exogenous beta-xylosides generated XylChol in a manner dependent on active lysosomal GBA but not the cytosol-facing beta-glucosidase GBA2. We later sought an endogenous beta-xyloside acting as donor in transxylosylation reactions, identifying xylosylated ceramide (XylCer) in cells and tissues that serve as donor in the formation of XylChol. UDP-glucosylceramide synthase (GCS) was unable to synthesize XylChol but could catalyze the formation of XylCer. Thus, food-derived beta-D-xyloside and XylCer are potential donors for the GBA-mediated formation of XylChol in cells. The enzyme GCS produces XylCer at a low rate. Our findings point to further catalytic versatility of GBA and prompt a systematic exploration of the distribution and role of xylosylated lipids. Show less
Deficiency of glucocerebrosidase (GBA), a lysosomal β-glucosidase, causes Gaucher disease. The enzyme hydrolyzes β-glucosidic substrates and transglucosylates cholesterol to cholesterol-β-glucoside... Show moreDeficiency of glucocerebrosidase (GBA), a lysosomal β-glucosidase, causes Gaucher disease. The enzyme hydrolyzes β-glucosidic substrates and transglucosylates cholesterol to cholesterol-β-glucoside. Here we show that recombinant human GBA also cleaves β-xylosides and transxylosylates cholesterol. The xylosyl-cholesterol formed acts as acceptor for subsequent formation of di-xylosyl-cholesterol. Common mutant forms of GBA from patients with Gaucher disease with reduced β-glucosidase activity were similarly impaired in β-xylosidase, transglucosidase and transxylosidase activities, except for a slightly reduced xylosidase/glucosidase activity ratio of N370S GBA and a slightly reduced transglucosylation/glucosidase activity ratio of D409H GBA. XylChol was found to be reduced in spleen from Gaucher disease patients. The origin of newly identified XylChol in mouse and human tissues was investigated. Cultured human cells exposed to exogenous β-xylosides generated XylChol in a manner dependent on active lysosomal GBA but not the cytosol-facing β-glucosidase GBA2. We later sought an endogenous β-xyloside acting as donor in transxylosylation reactions, identifying xylosylated ceramide (XylCer) in cells and tissues that serve as donor in the formation of XylChol. UDP-glucosylceramide synthase (GCS) was unable to synthesize XylChol but could catalyse formation of XylCer. Thus, food-derived β-D-xyloside and XylCer are potential donors for the GBA-mediated formation of XylChol in cells. The enzyme GCS produces XylCer at a low rate. Our findings point to further catalytic versatility of GBA and prompt a systematic exploration of the distribution and role of xylosylated lipids. Show less
Witjes, J.A.; Babjuk, M.; Bellmunt, J.; Bruins, H.M.; Reijke, T.M. de; Santis, M. de; ... ; Horwich, A. 2020
Background: Although guidelines exist for advanced and variant bladder cancer management, evidence is limited/conflicting in some areas and the optimal approach remains controversial.Objective: To... Show moreBackground: Although guidelines exist for advanced and variant bladder cancer management, evidence is limited/conflicting in some areas and the optimal approach remains controversial.Objective: To bring together a large multidisciplinary group of experts to develop consensus statements on controversial topics in bladder cancer management.Design: A steering committee compiled proposed statements regarding advanced and variant bladder cancer management which were assessed by 113 experts in a Delphi survey. Statements not reaching consensus were reviewed; those prioritised were revised by a panel of 45 experts prior to voting during a consensus conference.Setting: Online Delphi survey and consensus conference.Participants: The European Association of Urology (EAU), the European Society for Medical Oncology (ESMO), experts in bladder cancer management.Outcome measurements and statistical analysis: Statements were ranked by experts according to their level of agreement: 1-3 (disagree), 4-6 (equivocal), and 7-9 (agree). A priori (level 1) consensus was defined as >= 70% agreement and <= 15% disagreement, or vice versa. In the Delphi survey, a second analysis was restricted to stakeholder group(s) considered to have adequate expertise relating to each statement (to achieve level 2 consensus).Results and limitations: Overall, 116 statements were included in the Delphi survey. Of these statements, 33 (28%) achieved level 1 consensus and 49 (42%) achieved level 1 or 2 consensus. At the consensus conference, 22 of 27 (81%) statements achieved consensus. These consensus statements provide further guidance across a broad range of topics, including the management of variant histologies, the role/limitations of prognostic biomarkers in clinical decision making, bladder preservation strategies, modern radiotherapy techniques, the management of oligometastatic disease, and the evolving role of checkpoint inhibitor therapy in metastatic disease.Conclusions: These consensus statements provide further guidance on controversial topics in advanced and variant bladder canceir management until a time when further evidence is available to guide our approach.Patient summary: This report summarises findings from an international, multistake-holder project organised by the EAU and ESMO. In this project, a steering committee identified areas of bladder cancer management where there is currently no good-quality evidence to guide treatment decisions. From this, they developed a series of proposed statements, 71 of which achieved consensus by a large group of experts in the field of bladder cancer. It is anticipated that these statements will provide further guidance to health care professionals and could help improve patient outcomes until a time when good-quality evidence is available. (C) 2019 European Society of Medical Oncology and European Association of Urology. Published by Elsevier B.V. All rights reserved. Show less
Background: Although guidelines exist for advanced and variant bladder cancer management, evidence is limited/conflicting in some areas and the optimal approach remains controversial.Objective: To... Show moreBackground: Although guidelines exist for advanced and variant bladder cancer management, evidence is limited/conflicting in some areas and the optimal approach remains controversial.Objective: To bring together a large multidisciplinary group of experts to develop consensus statements on controversial topics in bladder cancer management.Design: A steering committee compiled proposed statements regarding advanced and variant bladder cancer management which were assessed by 113 experts in a Delphi survey. Statements not reaching consensus were reviewed; those prioritised were revised by a panel of 45 experts before voting during a consensus conference.Setting: Online Delphi survey and consensus conference.Participants: The European Association of Urology (EAU), the European Society for Medical Oncology (ESMO), experts in bladder cancer management.Outcome measurements and statistical analysis: Statements were ranked by experts according to their level of agreement: 1-3 (disagree), 4-6 (equivocal), 7-9 (agree). A priori (level 1) consensus was defined as >= 70% agreement and <= 15% disagreement, or vice versa. In the Delphi survey, a second analysis was restricted to stakeholder group(s) considered to have adequate expertise relating to each statement (to achieve level 2 consensus).Results and limitations: Overall, 116 statements were included in the Delphi survey. Of these, 33 (28%) statements achieved level 1 consensus and 49 (42%) statements achieved level 1 or 2 consensus. At the consensus conference, 22 of 27 (81%) statements achieved consensus. These consensus statements provide further guidance across a broad range of topics, including the management of variant histologies, the role/limitations of prognostic biomarkers in clinical decision making, bladder preservation strategies, modern radiotherapy techniques, the management of oligometastatic disease and the evolving role of checkpoint inhibitor therapy in metastatic disease.Conclusions: These consensus statements provide further guidance on controversial topics in advanced and variant bladder cancer management until a time where further evidence is available to guide our approach. Show less
The membrane lipid glucosylceramide (GlcCer) is continuously formed and degraded. Cells express two GlcCer-degrading β-glucosidases, GBA and GBA2, located in and outside the lysosome, respectively... Show moreThe membrane lipid glucosylceramide (GlcCer) is continuously formed and degraded. Cells express two GlcCer-degrading β-glucosidases, GBA and GBA2, located in and outside the lysosome, respectively. Here we demonstrate that through transglucosylation both GBA and GBA2 are able to catalyze in vitro the transfer of glucosyl-moieties from GlcCer to cholesterol, and vice versa. Furthermore, the natural occurrence of 1-O-cholesteryl-β-D-glucopyranoside (GlcChol) in mouse tissues and human plasma is demonstrated using LC-MS/MS and 13C6-labelled GlcChol as internal standard. In cells the inhibition of GBA increases GlcChol, whereas inhibition of GBA2 decreases glucosylated sterol. Similarly, in GBA2-deficient mice GlcChol is reduced. Depletion of GlcCer by inhibition of GlcCer synthase decreases GlcChol in cells and likewise in plasma of inhibitor-treated Gaucher disease patients. In tissues of mice with Niemann-Pick type C, a condition characterized by intralysosomal accumulation of cholesterol, marked elevations in GlcChol occur as well. When lysosomal accumulation of cholesterol is induced in cultured cells, GlcChol is formed via lysosomal GBA. This illustrates that reversible transglucosylation reactions are highly dependent on local availability of suitable acceptors. In conclusion, mammalian tissues contain GlcChol formed by transglucosylation through β-glucosidases using GlcCer as donor. Our findings reveal a novel metabolic function for GlcCer. Show less
Snoeck, M.; Engelen, B.G.M. van; Kusters, B.; Lammens, M.; Meijer, R.; Molenaar, J.P.F.; ... ; Kamsteeg, E.J. 2015
Second generation activists such as Yusuf al-Ayiri are now far more important than Osama bin Laden. They are regarded as true role models, the few who defend ideals and want to change “reality.”... Show moreSecond generation activists such as Yusuf al-Ayiri are now far more important than Osama bin Laden. They are regarded as true role models, the few who defend ideals and want to change “reality.” The author argues that to understand the appeal of al-Qaeda related groups, we should look not only at their globally communicated doctrines and ideals, but also analyse how these messages are, often locally, connected to political programmes and activism. Show less
Since May 2003 Saudi Arabia has been the scene of an armed confrontation between al-Qaida on the Arabian Peninsula (QAP) and the State. The Saudi authorities issued three lists of suspects who were... Show moreSince May 2003 Saudi Arabia has been the scene of an armed confrontation between al-Qaida on the Arabian Peninsula (QAP) and the State. The Saudi authorities issued three lists of suspects who were either wanted or already killed. These lists provide some insight into the background of QAP members and the nature of the organization. Show less
