Use of rapid combinatorial screening technology (CombiCult®) to create designer platelets optimized for tissue regeneration.

Dr Simon Pitchford, Institute of Pharmaceutical Science, King's College London
Dr Marina Tarunina, Plasticell Ltd

Project Description

This ambitious project at King’s College London (KCL) aims to elucidate how distinct platelet populations exist to perform regenerative functions, and to identify the molecular pathways that lead to the existence of ‘pro-regenerative’ platelets from megakaryocytes derived from iPSCs using CombiCult® technology in an exciting collaboration with the industrial partners Plasticell Ltd, who have developed the CombiCult® technology.


For regenerative medicine, platelets have considerable potential to restore the function of tissues and organs damaged by trauma. This is because platelets interact with stem cells to induce cellular proliferation, differentiation, and are themselves a huge store of pro-regenerative cytokines and growth factors. Currently, there are major issues with using platelet rich plasma (PRP) for these clinical applications, including inconsistency between samples, pathogen contamination, and restricted shelf life (5 days). Furthermore, current PRP preparations have not been selected for enhanced regenerative capacity, and are essentially identical to PRP preparations used for haemostatic transfusions. Manufactured platelets can mitigate these issues and also provide a novel opportunity to create optimized platelet phenotypes specifically for tissue regeneration.


A shift in platelet phenotype (described as a ‘pro-angiogenic’ or ‘pro-regenerative’ shift) can occur in certain contexts, with platelets produced that have differential packaging and secretion of pro-regenerative or anti-regenerative contents. We have shown that the pro-regenerative cytokine vascular endothelial growth factor (VEGF) can boost platelet production via VEGFR1 in vivo via an SDF-1α dependent process (Pitchford et al., 2012). Whilst it remains unknown how a ‘nuanced’ population of platelets can be selected and produced, various identified different growth factors and ligands for chemokine receptors are involved in reactive thrombopoiesis as a result of injury. The biological problem that this PhD project will solve is therefore to identify how these molecular pathways create a ‘pro-regenerative’ platelet population from differentiated megakaryocytes and their stem cell precursors.


Hitherto, the technology has not been available to purify ‘forced’ platelet populations for detailed evaluation of their physiological function(s), or to evaluate other pathways that may be involved in megakaryocyte differentiation and platelet production that would be of relevance to tissue regeneration because controlled stem cell differentiation is a key problem in the development of biopharmaceuticals. Our industrial partners at Plasticell Ltd have developed the CombiCult® technology, which provides a unique opportunity to overcome these technical hurdles as a precise and adaptable high throughput screening method using combinatorial cell culture techniques that rapidly produces stem cell progeny with many different phenotypes (Tarunina et al., 2016).


WORK PROGRAMME: This 4 year Phd project will be conducted at the Sackler Institute of Pulmonary Pharmacology (SIPP) at King’s College London under the supervision of Dr Simon Pitchford and Prof Clive Page. SIPP has led the international research field in investigating the roles of platelets during inflammation and trauma, which are recognisably distinct pathologies from the well-recognised roles of platelets during haemostasis and events leading to thrombosis. It is anticipated that the student will learn skills and assays by the supportive team at KCL, for example platelet preparation, phenotype analysis, and functional assays. Functional analysis of platelets produced via existing CombiCult screens would then be conducted for their pro, and anti-regenerative capacities. The student will move forward to study which of the identified biological pathways best enables production of pro-regenerative platelets. This will be combined with industrial placement opportunities at Plasticell Ltd where the student will learn iPSC megakaryocyte culture and an introduction to the use of CombiCult® technology. The student will then design pro-regenerative platelets using controlled conditions and analyse using complex bioinformatics. The design and production of specific platelet populations will then occur before evaluation at KCL for functional analysis of their pro, and anti-regenerative capacities, and their interactions with specific stem cell subtypes associated with tissue regeneration.

Application

Interested applicants are encouraged to contact Dr Simon Pitchford (simon.pitchford@kcl.ac.uk) in advance of the deadline.

Closing date is 19th January. Please ensure that you read the Guidelines before submitting an application. Your application and supporting documents should be sent in a single email to LIDo.Admissions@ucl.ac.uk

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