Functions of Heparan Sulphate in the C. elegans Nervous System

Lead Research Organisation: University of Liverpool
Department Name: Sch of Biological Sciences

Abstract

My research is aimed at understanding the development of the nervous system at the molecular level. I am particularly interested in a group of complex glycoproteins, heparan sulphate proteoglycans (HSPGs). My research uses the nematode Caenorhabditis elegans as a simplistic genetic model.
Understanding neuronal development is one of the fundamental questions in biology as neurons control actions from movement to autonomous functions such as heart beat and breathing, and our ability to sense, think and remember. The adult human brain has over hundred billion neurons which each make connections with an average of 1000 target cells, yet mistakes happen very rarely. Neuron migration and formation of neuronal connections during development are genetically determined and dictate the wiring of the entire nervous system, yet the molecular mechanisms are still poorly understood.
HSPGs are present in cell membranes and in the extracellular space between cells. HSPGs mediate interactions of cells with their environment and play critical roles in regulating development and homeostasis. In the nervous system HSPGs guide migrating neurons and their processes, and control functions involved in learning and memory.
C. elegans contains homologues of key genes involved in human neuronal development. A simplified model is expected to improve understanding of HSPGs in normal cellular communication. Understanding normal development will provide novel insights into mechanisms that underlie cancer, degenerative neuronal diseases such as Alzheimer’s and Parkinson’s, and regeneration after injury.

Technical Summary

Heparan sulfate proteoglycans (HSPGs) are ubiquitous glycoproteins of the cell surface and of the extracellular matrix that contain a protein core substituted with heparan sulfate (HS) polysaccharide chains. HS chains encode complex sugar sequences with variant sulfation patterns that confer biological functions as protein regulators. Thus HS/HSPGs play essential roles in controlling cell differentiation, tissue morphogenesis and homeostasis. In the nervous system, HS and HSPGs have been implicated in neuron migration, axon guidance, synapse formation and maturation and control of physiological responses such as feeding, learning and memory. The importance of HSPGs and HS has been highlighted by the findings that a number of human genetic disorders are associated with mutations in genes encoding for HSPGs or HS biosynthetic enzymes. Changes to the fine structure of HS in malignant transformation imply a role in cancer. Furthermore, HS and HSPGs control amyloid formation thus contributing to neurodegenerative diseases such as Alzheimer?s.
The C. elegans genome contains in most cases a single ortholog of vertebrate HSPGs and HS biosynthetic enzymes providing an excellent and uniquely tractable model to study the structural complexity of HSPGs in vivo without genetic redundancy. Importantly, there are existing mutant alleles available in all HSPG core proteins and in enzymes involved in biosynthesis and breakdown of HS. The proposed research exploits C. elegans as a model to resolve the functions of HS and HSPGs in neuronal development using a unique combination of molecular genetics and biochemistry. This will entail:
1. Biochemical identification of HSPGs and their function in the C. elegans nervous system especially in the context of neuron migration, axon outgrowth and synapse assembly
2. Structure-function relationship of HS using both genetic and biochemical approaches
3. Identification of the signalling pathways regulated by HS and HSPGs

As many of the basic biological signalling pathways are highly conserved from nematodes to mammals, results from this research are expected to uncover novel functions of HSPGs applicable to human biology, neuronal disorders and diseases, and into mechanisms controlling regeneration after injury.
 
Description NC3R Training Grant
Amount £90,000 (GBP)
Funding ID NC/M001717/1 
Organisation National Centre for the Replacement, Refinement and Reduction of Animals in Research (NC3Rs) 
Sector Private
Country United Kingdom
Start 10/2015 
End 12/2018
 
Description Travel Grant
Amount £1,200 (GBP)
Organisation The Royal Society 
Sector Academic/University
Country United Kingdom
Start 04/2007 
End 04/2007
 
Title Analysis of C. elegans heparan sulphate 
Description improvement of compositional analysis of C. elegans heparan sulphate 
Type Of Material Technology assay or reagent 
Provided To Others? No  
Impact The imporvements will make it more feasible to analyse heparan sulfate from a number of different mutant strains and compare sugar stuctures between strains 
 
Title C. elegans models of human genetic disease 
Description we have introduced mutations that model human genetic diseases into the orthologous genes in C. elegans to assess the mechanisms how the human mutation causes disease 
Type Of Material Model of mechanisms or symptoms - non-mammalian in vivo 
Year Produced 2012 
Provided To Others? Yes  
Impact These mutant C. elegans strains have provided insight into the mechanisms leading to disease in humans and will provide a tool to discover novel therapies. All published materials will be provided to other researchers upon request. 
 
Title C. elegans strains 
Description C. elegans strains carrying cell specific reporter genes/transgenic arrays with mutated DNA constructs to study gene function in vivo/novel C. elegans strains carrying combinations of multiple mutations 
Type Of Material Database/Collection of Data/Biological Samples 
Year Produced 2008 
Provided To Others? Yes  
Impact insights into gene function in vivo/ tools for further research 
 
Title DNA 
Description DNA constructs 
Type Of Material Database/Collection of Data/Biological Samples 
Provided To Others? No  
Impact The DNAs will be disseminated upon request once published 
 
Title DNA constructs 
Description DNA constructs containing orthologous mutations to those found in human patients 
Type Of Material Database/Collection of Data/Biological Samples 
Year Produced 2012 
Provided To Others? Yes  
Impact novel roles for synaptogenesis 
 
Description Beta-Klotho in reproduction 
Organisation University of Lausanne
Country Switzerland 
Sector Academic/University 
PI Contribution invetigation of human beta-Klotho mutations in vivo
Collaborator Contribution identification of human beta-Klotho mutations in patients of neurological syndromes affecting reproduction
Impact multi-disciplinary including human clinical endocrinology and model organism genetics in vivo; first output expected to be submitted early 2013
Start Year 2012
 
Description EU FP6 Marie Curie Early Stage Training Network "MolFun" 
Organisation University of Liverpool
Department School of Biological Sciences Liverpool
Country United Kingdom 
Sector Academic/University 
PI Contribution Joint applicant in an EU FP6 Marie Curie Early Stage Training Network "MolFun" funding 6 postgraduate studentships. I have been the primary supervisor to one of the postgraduate studnets, who is now finalising her thesis.
Collaborator Contribution Provided a PhD training studentship
Impact This collabotative studentship network, which has funded 6 postgraduate students has so far resulted in a number of conference abstracts, platform talks, original publications and review articles. Further publications are expected. PubMed ID's for publications to date are: 19801543, 18985724, 19567366, 19400583, 18508514, 18508513. Publications that have rsulted from work carried out under my direct supervision are 19801543, 18985724
Start Year 2006
 
Description Heparan 3-O-sulphation 
Organisation Dartmouth College
Department Geisel School of Medicine
Country United States 
Sector Academic/University 
PI Contribution functional and genetic pathway analysis of specific sugar structures in vivo
Collaborator Contribution contributed to invaluable reagents and tools for my research
Impact manuscript in preparation; HFSP project grant application (which unfortunately was unsuccessful). We are currently collating further data to enhance further application.
Start Year 2008
 
Description MTA 
Organisation Eli Lilly & Company Ltd
Country United Kingdom 
Sector Private 
PI Contribution Analysed the biological functions of the materials provided by the collaborator
Collaborator Contribution Materials transfer
Impact This collaboration has thus far resulted in one manuscript which has been re-submitted to Journal of Biological Chemistry after minor revisions as suggested by the reviewers. This collaboration has also lead to further projects, which will be applied further funding for.
Start Year 2008
 
Description Careers seminar 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Public/other audiences
Results and Impact 30 PGR studnets and early career postdocs attended a lecture course, part of which covered the topic of careers. My role was to give a plenary talk to the careers session prior to panel discussion.

helping PGR students and early career post docs in deciding their future careers
Year(s) Of Engagement Activity 2011
 
Description Invited Conference talk -Gordon Conference in FGFs USA, 2019 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other audiences
Results and Impact invited conference talk at Gordon Conference for Fibroblast Growth Factors in Development and Disease, Ventura, USA 2018; audience of about 130 conference participants from academia and industry
Year(s) Of Engagement Activity 2018
URL https://www.grc.org/fibroblast-growth-factors-in-development-and-disease-conference/2018/
 
Description Invited talk in BBSRC UK-China Glycoscience Network Meeting, Shanghai, China 2017 
Form Of Engagement Activity A talk or presentation
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Professional Practitioners
Results and Impact BBSRC funded UK-China Glycoscience Network meeting which took place in Shanghai China, November 2017. This meeting resulted in further visit to South China University of Technology, Guangzhou, China, to discuss further research links and collaborations
Year(s) Of Engagement Activity 2017
 
Description careers seminar 
Form Of Engagement Activity A formal working group, expert panel or dialogue
Part Of Official Scheme? Yes
Type Of Presentation Workshop Facilitator
Geographic Reach International
Primary Audience Postgraduate students
Results and Impact 25 students attended a pre-conference seminar aimed at providing opportunities for networking, learning about career options

PGR students more informed about career choises
Year(s) Of Engagement Activity 2012