PhD Research Studentships
The role of primary cilia in tendinopathy. (Institute of Bioengineering PhD Studentship)
| Supervisor: | m.m.knight@qmul.ac.uk,h.r.c.screen@qmul.ac.uk |
| Apply by: | 1 June 2013 |
Description
Tendon is mechanosensitive, maintaining tissue health in response to applied loads. Overload is a key contributor to the development of tendon pathologies, know as tendinopathies1,2; a range of highly debilitating and increasingly prevalent conditions2-3. However, the mechanisms associated with tendinopathy development remain unclear. Current evidence supports a combined mechanical and cellular pathway, with early structural damage initiating a catabolic cell response1,2,4. Primary cilia consist of a single microtubule axoneme, 2-4µm in length, which projects into the extracellular environment and regulates fundamental signalling pathways including mechanotransduction, hedgehog (Hh) and Wnt signalling which are important in tissue development, health and disease. Although primary cilia have been identified in tendon, their precise function is unknown5. Recent studies of cilia in cartilage indicate that they are essential for tissue development6 and mechanotransduction mediated matrix synthesis7. Furthermore cilia may play a major role in the aetiology of osteoarthritis (OA) through upregulation of Hh signalling8 and alterations in hypoxia inducible factor (HIF) expression (un-published data). Work from Knight’s group also suggests that physicochemical changes in the OA microenvironment, including mechanical loading and inflammatory cytokines, disrupt primary cilia structure and associated signalling pathways9. As a tissue damaged through injurious overload, it is reasonable to hypothesise that similar cilia mediated mechanotransduction pathways may be present in tendon. This studentship will test the overall hypothesis that injurious mechanical loading influences primary cilia structure & function, creating a catabolic cell response & leading to the development of tendinopathy. A series of specific hypothesis will consider the role of the cilia in tendon development, health and pathology: Hypothesis 1 - Primary cilia are necessary for tendon development. Initially the student will determine whether primary cilia are required for the development of functionally different tendons. This will involve biochemical, histological and mechanical testing of tail tendon fascicles and Achilles tendons from mouse models with known genetic cilia mutations. These models are available through Knight’s collaboration with leading cilia expert, Prof Beales at the Institute of Child Health, UCL. Hypothesis 2 - Tendon mechanical injury regulates cilia structure. Screen has recently developed a physio-mimetic of tendinopathy, in which early stage fatigue leads to localised matrix disruption in the non-collagenous matrix and a resulting inflammatory cell response, with elevated level of IL-610,11. In the proposed study equine tendon fascicles will be subjected to mechanical injury prior to examination of cilia structure, both in situ and in isolated cells. Cilia will be labelled with anti-acetylated α-tubulin and visualised using confocal microscopy enabling quantification of cilia prevalence and length. The student will examine cilia in different areas of the tendon and investigate the temporal and dose dependant response to mechanical injury, as well as the mechanisms responsible for regulating cilia length12. Studies will also examine difference in cilia expression between functionally different tendons. Hypothesis 3 - Mechanical injury disrupts cilia-mediate tenocyte mechanotransduction and matrix synthesis. Tenocytes will be isolated from injured and control tendon fascicles and mechanically stimulated using a novel tendon-mimetic hydrogel construct developed by Screen13. Downstream synthesis of matrix molecules will be quantified by at gene and protein level. As a positive control, siRNA transfection of IFT88, the inter-flagellar transport gene that regulates cilia assembly, will be used to produce tenocytes with stunted or no primary cilia, following protocols optimised by Knight’s group. Hypothesis 4 - Mechanically induced tendinopathy regulates catabolic cilia signalling and matrix degradation. Optimised fatigue injury of tendon fascicles will be used to determine whether there is an associated change in catabolic primary cilia signalling. In particular this will examine whether mechanical injury regulates HIF expression and downstream catabolic signalling as previously suggested in tendinopathy14. We have recently shown that primary cilia length is an important regulator of HIF signalling such that we now hypothesis that mechanical disruption of the cilia will increase catabolic HIF signalling. The student will also examine Hh signalling which we have shown to be mechanically up-regulated in chondrocytes leading to increased expression of ADAMTS5 and matrix catabolism8. These studies will involve a variety of techniques already established within the Knight/Screen group including PCR, siRNA of IFT88, confocal localisation of HIFs and biochemical analysis of catabolic mediators (NO, PGE2). References: 1. Fung et al., (2010) J. Biomech 43:274. 2. Riley (2008) Nat Clin Pract Rheumatol. 4(2):82. 3. Bevan et al. (2007) The Work Foundation. 4. Legerlotz et al. (2011) Int. J. Exp. Pathol. 92(3):A10. 5. Donnelly et al. (2010) J Orthop Res. 28(1):77. 6. Chang et al., (2012) Osteoarth Cart 20(2):152. 7. Wann et al. (2012) FASEB J 26(4):1663. 8. Lin et al. (2009) Nature Med 15(12):1421. 9. Wann & Knight (2012) Cell Mol Life Sci. 69(17):2967. 10. Legerlotz et al. (2012) Scand. J. Med. Sci. Sport 23(1);31. 11. Shepherd et al. (2012) BSMB Tendinopathy 10. 12. Prodromou et al. (2012) J Cell Sci. 125(18):4297. 13. Screen et al., (2010) Adv. Funct Mats. 20:1. 14. Lakemeier (2010) BMC Musculo Dis 11:230. For informal enquiries about this position, please contact: Professor Knight, E-mail: m.m.knight@qmul.ac.uk Dr Hazel Screen, E-mail: h.r.c.screen@qmul.ac.uk QMUL Institute of Bioengineering This PhD studentship is offered through the QMUL Institute of Bioengineering which is a new cross-faculty initiative bringing together over 40 academics from the faculties of Medicine & Dentistry and Science & Engineering. The Institute will provide a focus for ground-breaking research aimed at the development of new medical technologies to meet the key healthcare challenges of the 21st century. There are three research themes namely: ‘medical devices and biomonitoring’, ‘biomaterials and interfaces’ and ‘biomechanics and mechanobiology’. QMUL Research Studentship Details • Available to Home/EU/International Applicants • Full Time research degree programme only • Applicants will be required to start the degree programme in September/October 2013. • The studentship arrangement will cover tuition fees and provide an annual stipend (£15,590 in 2012/13) for up to three years. • The minimum requirement for this studentship opportunity is a good Honours degree (minimum 2(i) honours or equivalent) or MSc/MRes in a relevant discipline. • Students must be able to demonstrate “a capability to undertake and benefit from research training through to completion, to the standard necessary to qualify for a PhD.” • International applicants should refer to the following website at http://www.qmul.ac.uk/international/index.html • If English is not your first language then you will require a valid English certificate equivalent to IELTS 6.5+ overall with a minimum score of 5.5 in all sections (Reading, Listening, Writing, Speaking). Application Method: Applicants may apply for up to 3 different projects but should indicate their order of preference on a covering letter. To apply for this studentship and for entry on to the Medical Engineering PhD programme (Full Time, Semester 1 start) please complete the online application form: https://mysis.qmul.ac.uk/urd/sits.urd/run/siw_ipp_lgn.login?process=siw_ipp_app&code1=RFQM-H3ZM-09&code2=0004&code3=GUEST During the online application process you will be asked to provide details of any funding you are applying for, please be sure to include a reference to ‘2013 BIOENGINEERING’ to associate your application with this studentship opportunity. For General Enquiries in regards to the application process please email the SEMS Research Administrator, Mr Jonathon Hills on j.hills@qmul.ac.uk
Eligibility
- The minimum requirement for this studentship opportunity is a good honours degree (minimum 2(i) honours or equivalent) or MSc/MRes in a relevant discipline.
- If English is not your first language, you will require a valid English certificate equivalent to IELTS 6.5+ overall with a minimum score of minimum score of 6.0 in each of Writing, Listening, Reading and Speaking).
- Candidates are expected to start in (Semester ).
Contact
For informal enquiries about this opportunity, please contact m.m.knight@qmul.ac.uk,h.r.c.screen@qmul.ac.uk.
| Related website: | http://www.bioengineering.qmul.ac.uk/ |