Dr Dan Sillence

Job: Reader in Cell Biology

Faculty: Health and Life Sciences

School/department: Leicester School of Pharmacy

Address: De Montfort University, The Gateway, Leicester, LE1 9BH.

T: +44 (0)116 250 6368

E: dsillence@dmu.ac.uk

W: www.dmu.ac.uk/hls

 

Personal profile

The Glycosphingolipid (GSL) storage diseases are a group of diseases where GSLs accumulate in tissues due to a defect in their lysosomal breakdown. GSL storage diseases have varying degrees of central nervous system involvement and in Tay-Sachs and Sandhoff diseases the neuropathology is very severe and frequently lethal in early infancy.

How lysosomal storage of GSL causes such severe neuropathology is not known at present. A strategy that can be applied to treat these diseases is substrate deprivation.

This approach aims to balance the rate of GSL biosynthesis with the impaired rate of catabolism, thus preventing accumulation of GSLs. Two imino sugar inhibitors of Glucosylceramide synthase, which catalyses the first step in GSL synthesis.

How does the storage of lipids lead to disease?

What are the normal functions of the lipids that accumulate?

Research group affiliations

Pharmacology

Publications and outputs 

  • Cytosolic Glucosylceramide regulates endolysosomal function in Niemann-Pick type C disease
    Cytosolic Glucosylceramide regulates endolysosomal function in Niemann-Pick type C disease Sillence, Daniel J.; Bhardwaj, Meenakshi; Tongue, Paige; Schmid, Ralf; Haberkant, Per; Wheeler, S. Niemann-Pick type C disease (NPCD) is a neurodegenerative disease associated with increases in cellular cholesterol and glycolipids and most commonly caused by defective NPC1, a late endosomal protein. Using ratiometric probes we find that NPCD cells show increased endolysosomal pH. In addition U18666A, an inhibitor of NPC1, was found to increase endolysosomal pH, and the number, size and heterogeneity of endolysosomal vesicles. NPCD fibroblasts and cells treated with U18666A also show disrupted targeting of fluorescent lipid BODIPY-LacCer to high pH vesicles. Inhibiting non-lysosomal glucocerebrosidase (GBA2) reversed increases in endolysosomal pH and restored disrupted BODIPY-LacCer trafficking in NPCD fibroblasts. GBA2 KO cells also show decreased endolysosomal pH. NPCD fibroblasts also show increased expression of a key subunit of the lysosomal proton pump vATPase on GBA2 inhibition. The results are consistent with a model where both endolysosomal pH and Golgi targeting of BODIPY-LacCer are dependent on adequate levels of cytosolic-facing GlcCer, which are reduced in NPC disease. A new paradigm for Niemann-Pick C disease is presented where lysosomal storage leads to a deficit in cytoplasmic glucosylceramide (GlcCer) where it performs important functions. Previously it had been reported that Gaucher cells have defective endolysosomal pH. GlcCer also accumulates in Niemann-Pick C disease and also shows this defect. Niemann-Pick C cells were found to have reduced cytoplasmic glucosylceramide (GlcCer) transport. Inhibiting cytoplasmic glucocerebrosidase (GBA2), increased GlcCer, decreased endolysosomal pH in normal cells, reversed increases in endolysosomal pH and restored disrupted BODIPY-LacCer trafficking and increased expression of vATPase a subunit in Niemann-Pick C fibroblasts. The results are consistent with a model where both endolysosomal pH and Golgi targeting of BODIPY-LacCer are dependent on adequate levels of cytosolic GlcCer which are reduced in NPC disease. This work consequently suggests GBA2 and vATPase as new therapeutic targets in Niemann-Pick C and related neurodegenerative diseases. The work was in collaboration with colleagues in the Netherlands and Leicester University. The file attached to this record is the author's final peer reviewed version. The Publisher's final version can be found by following the DOI link.
  • Lipid–Protein Interactions in Niemann–Pick Type C Disease: Insights from Molecular Modeling
    Lipid–Protein Interactions in Niemann–Pick Type C Disease: Insights from Molecular Modeling Wheeler, S.; Schmid, R.; Sillence, Daniel J. The accumulation of lipids in the late endosomes and lysosomes of Niemann–Pick type C disease (NPCD) cells is a consequence of the dysfunction of one protein (usually NPC1) but induces dysfunction in many proteins. We used molecular docking to propose (a) that NPC1 exports not just cholesterol, but also sphingosine, (b) that the cholesterol sensitivity of big potassium channel (BK) can be traced to a previously unappreciated site on the channel’s voltage sensor, (c) that transient receptor potential mucolipin 1 (TRPML1) inhibition by sphingomyelin is likely an indirect effect, and (d) that phosphoinositides are responsible for both the mislocalization of annexin A2 (AnxA2) and a soluble NSF (N-ethylmaleimide Sensitive Fusion) protein attachment receptor (SNARE) recycling defect. These results are set in the context of existing knowledge of NPCD to sketch an account of the endolysosomal pathology key to this disease. open access article
  • Mechanisms of Gaucher Disease Pathogenesis
    Mechanisms of Gaucher Disease Pathogenesis Wheeler, S.; Sillence, Daniel J. Gaucher disease is caused by mutations in the Gba1 gene encoding an acid β-glucocerebrosidase (GBA1), the lysosomal hydrolase which breaks down glucosylceramide (GlcCer). In Gaucher type 1 disease the accumulation of this simple glycolipid is mainly restricted to tissue phagocyte lysosomes resulting ultimately in hepatomegaly, splenomegaly and osteopenia. Lower residual GBA1 levels leads to neuronal storage, in types 2 and 3 neurological symptoms are characterised by acute (death at age 2) or sub-acute onset, respectively. The links between cellular changes and clinical manifestations are largely unknown but are the key to the development and monitoring of new therapies. The newcomer to Gaucher disease is likely attracted to the apparent simplicity of an autosomal recessive disorder which promises to unravel the critical GlcCer function in normal cells (GlcCer is widespread, it’s even present in some bacteria—also, mouse and fly GlcCer knockouts die at embryo stage). However, closer acquaintance reveals not a classic Mendelian disorder—sometimes even monozygotic twins have different symptoms—and studies at the cellular level have so far failed to reveal clear GlcCer functions. Now a team led by Ellen Sidransky at the NIH has taken what appears to be a big step forward by producing two in vitro models of Gaucher cells (1).
  • 1H NMR-Linked Urinary Metabolic Profiling of Niemann-Pick Class C1 (NPC1) Disease: Identification of Potential New Biomarkers using Correlated Component Regression (CCR) and Genetic Algorithm (GA) Analysis Strategies
    1H NMR-Linked Urinary Metabolic Profiling of Niemann-Pick Class C1 (NPC1) Disease: Identification of Potential New Biomarkers using Correlated Component Regression (CCR) and Genetic Algorithm (GA) Analysis Strategies Ruiz-Rodado, Victor; Luque-Baena, R. M.; te Vruchte, D. J.; Probert, Fay; Lachmann, R. H.; Hendriksz, Christian J.; Wraith, James E.; Imrie, Jackie; Elizondo, David; Sillence, Daniel J.; Clayton, P.; Platt, Frances M.; Grootveld, M. Niemann-Pick Class 1 (NPC1) disease is a rare, debilitating neurodegenerative lysosomal storage disease; however, urinary biomarkers available for it and its prognosis are currently limited. In order to identify and establish such biomarkers, we employed high-resolution 1H NMR analysis coupled to a range of multivariate (MV) analysis approaches, i.e. PLS-DA, RFs and uniquely the cross-validated correlated component regression (CCR) strategy in order to discern differences between the urinary metabolic profiles of 13 untreated NPC1 disease and 47 heterozygous (parental) carrier control participants. Novel computational intelligence techniques (CITs) involving genetic algorithms (GAs) were also employed for this purpose
  • Relative acidic compartment volume as a lysosomal storage disorder–associated biomarker
    Relative acidic compartment volume as a lysosomal storage disorder–associated biomarker te Vruchte, Danielle; Speak, Anneliese O.; Wallom, Kerri L.; Al Eisa, Nada; Smith, David A.; Hendriksz, Christian J.; Simmons, Louise; Lachmann, R. H.; Cousins, Alison; Hartang, Ralf; Mengel, Eugen; Runz, Heiko; Beck, Micheal; Amraoui, Yasmina; Imrie, Jackie; Jacklin, Elizabeth; Riddick, Kate; Yanjanin, Nicole M.; Wassif, Christopher A.; Rolfs, Arndt; Rimmele, Florian; Wright, Naomi; Taylor, Clare; Ramaswami, Uma; Cox, Timothy M.; Hastings, Caroline; Jiang, Xuntian; Sidhu, Rohini; Ory, Daniel S.; Arias, Begona; Jeyakumar, Mylvaganam; Sillence, Daniel J.; Wraith, James E.; Porter, Forbes D.; Cortina-Borja, Mario; Platt, Frances M. Lysosomal storage disorders (LSDs) occur at a frequency of 1 in every 5,000 live births and are a common cause of pediatric neurodegenerative disease. The relatively small number of patients with LSDs and lack of validated biomarkers are substantial challenges for clinical trial design. Here, we evaluated the use of a commercially available fluorescent probe, Lysotracker, that can be used to measure the relative acidic compartment volume of circulating B cells as a potentially universal biomarker for LSDs. We validated this metric in a mouse model of the LSD Niemann-Pick type C1 disease (NPC1) and in a prospective 5-year international study of NPC patients. Pediatric NPC subjects had elevated acidic compartment volume that correlated with age-adjusted clinical severity and was reduced in response to therapy with miglustat, a European Medicines Agency–approved drug that has been shown to reduce NPC1-associated neuropathology. Measurement of relative acidic compartment volume was also useful for monitoring therapeutic responses of an NPC2 patient after bone marrow transplantation. Furthermore, this metric identified a potential adverse event in NPC1 patients receiving i.v. cyclodextrin therapy. Our data indicate that relative acidic compartment volume may be a useful biomarker to aid diagnosis, clinical monitoring, and evaluation of therapeutic responses in patients with lysosomal disorders.
  • Lipid Rafts; Properties, Controversies and Roles in Signal Transduction
    Lipid Rafts; Properties, Controversies and Roles in Signal Transduction Sillence, Daniel J.
  • Glucosylceramide modulates endolysosomal pH in Gaucher disease
    Glucosylceramide modulates endolysosomal pH in Gaucher disease Sillence, Daniel J.
  • Glycosphingolipid storage leads to the enhanced degradation of the B cell receptor in Sandhoff disease mice.
    Glycosphingolipid storage leads to the enhanced degradation of the B cell receptor in Sandhoff disease mice. te Vruchte, D. J.; Jeans, A.; Platt, Frances M.; Sillence, Daniel J.
  • Niemann-Pick disease type C1 is a sphingosine storage disease that causes deregulation of lysosomal calcium.
    Niemann-Pick disease type C1 is a sphingosine storage disease that causes deregulation of lysosomal calcium. Lloyd-Evans, E.; Morgan, A. J.; He, X.; Smith, D. A.; Elliot-Smith, E.; Sillence, Daniel J.; Churchill, G. C.; Schuchman, E. H.; Galione, A.; Platt, Frances M.
  • New insights into glycosphingolipid functions--storage, lipid rafts, and translocators.
    New insights into glycosphingolipid functions--storage, lipid rafts, and translocators. Sillence, Daniel J.

Click here for a full listing of Dan Sillence‘s publications and outputS.

Research interests/expertise

  • Sphingolipid cell biology
  • Lysosomal storage diseases.

Areas of teaching

  • Cell Biology
  • Pharmacology

Qualifications

BSc PhD (Biochemistry, Dundee)

Courses taught

  • Cell Biology and Physiology
  • Pharmacology

Honours and awards

Marie Curie Research Fellow, ‘Transbilayer flipping of sphingolipids’ EU, (2000)

Peter Jones Carlton memorial award (2006) for new therapy for Niemann-Pick C disease with Emyr Lloyd-Evans and Prof Frances Platt, University of Oxford.

Membership of professional associations and societies

American Society for Molecular Biology

Marie Curie Alumni

Consultancy work

Sphingolipid cell biology, Unilever UK.

Externally funded research grants information

Sillence DJ ‘Simple sphingolipids in neurodegeneration’ HEIF Innovation, £15K (Oct 17-18) PI

Grootveld M., F. Platt, D. Sillence ‘Identification of New Biomarkers for the Metabolomics Classification of Batten Disease: A Drug-Targeting Strategy’ Beyond Batten Disease Foundation (Oct 2016-9), £120K Co-PI

Wheeler S and Sillence D ‘Modelling lysosomal storage diseases’ DMU High Flier studentship (Sept 2016-19), £45K PI

Silence DJ ‘Niemann Pick C and vATPase’ HEIF5 (sept 15- July 16) £1500

Grootveld M. D. Sillence, F. Platt, A. D’Azzo, C. Tifft, HEIF_5 Collaborative Award (2015-2016), £35K     

Establishment and Operation of an Interdisciplinary Global Lysosomal Diseases Metabolomics Research Group (IGLDMRG) Sillence D (with T. Zetterstrom) DMU Fees-Only PhD Scholarship Award, 2014-2017, £12.5K            

A role for sphingolipids in the action of anti-depressants Rushworth,J, Morris, M. Fretwell, L. Slater, A.  Dunford,L. Grootveld, M. Sillence DJ, Ruparelia,K, Bhambra, A, Arroo R. (2014) Cell imaging and analysis facility RCIF2, £77,600

Grootveld, M, Sillence D., Platt, FM (2013) Identification of Novel Biomarker Patterns for the Metabolomic Classification of Niemann-Pick Disease C and Response to Treatment SPARKS, £51,000

Sillence D, Grootveld M (2013) Identification of Novel Biomarker Patterns for the Metabolomic Classification of Niemann-Pick Disease C and its Response to Treatment Small Projects Scheme, £5,000 Co-PI

Assay of sphingomyelinase inhibitors, Off-Label Ltd/Penn Ltd, research project, July 2008 – Nov 2008, PI.

Internally funded research project information

Sphingolipid cell biology, Startup – 1/1/2008 – 2009, PI.

Case studies

  • Sillence,D J (Nov 2007) New insights into glycosphingolipid functions--storage, lipid rafts, and translocators. International Review of Cytology, 262, pp 151-189.
  • Niemann-Pick disease type C1 is a sphingosine storage disease that causes deregulation of lysosomal calcium. Lloyd-Evans,E, Morgan,A J, He,X, Smith,D A, Elliot-Smith,E, Sillence,Daniel J, Churchill,G C, Schuchman,E H, Galione, A, Platt,F M.  Nature Med. (2008).

Invited editorial board membership

‘Universal Journal of Medical Science’

‘Conference papers in Cell Biology’

‘International Journal of Clinical Pharmacology and Toxicology’

‘Peertechz Journal of Cytology and Pathology’

Research supervision

Post-Doc

NMR-linked metabolomics in Batten disease, Dr Nikol Sullo, (2016-8)

Post-Doctoral Fellowship in NMR-Linked Metabolomics in Niemann-Pick C disease, Dr Fay Probert, (2013-15)

Research Assistant Danielle TeVruchte (2002-11)

PhD supervision

Simon Wheeler (2016-9) Sphingolipids and Neurodegeneration (1st)

Victor Ruiz Rodado (2013-6) Metabolomics of Niemann-Pick C disease (2nd)

Emyr Lloyd-Evans (2003-6) Lysosomal calcium defect in Niemann-Pick C disease (1st)

Aruna Jeans (2002-5) Immune cell dysfunction in glycolipid storage disease (2nd)

Renee Raggers (1998-2001) Lipid translocation by multidrug transporters (2nd)

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