Molecular dissection of the role of ARAP3 in angiogenesis

Lead Research Organisation: Babraham Institute
Department Name: UNLISTED

Abstract

Consistent delivery of oxygen and nutrients to all cells is vital for multicellular organisms. This need becomes particularly apparent during embryonic development or during growth of tumours. To be successful, in both cases, blood vessels need to be formed, by a specialised process termed angiogenesis. Angiogenesis is a very comlex process which requires the co-ordinated action of multiple cellular factors within specialised cells. When the process fails, the developing embryo (or tumour) dies. ARAP3 is a signalling protein which regulates cross-talk between small GTPase proteins of different subfamilies, and which is regulated itself by phosphoinositide 3OH-kinase (PI3K), a key regulator of many cellular processes. We have very recently derived two ARAP3 models, where we can analyse the results of loss of ARAP3 or a situation where the protein is no longer under the control of PI3K. We find that both loss of ARAP3 and loss of its regulation by PI3K leads to embryonic death due to an angiogenesis defect, indicating that ARAP3 is required for embryonic angiogenesis and that this is regulated by PI3K. This project aims to understand why this happens, and which of the small GTPases that ARAP3 talks to are important for this.
 
Description This work explored the physiological function of ARAP3, a poorly characterised effector of phosphoinositide 3-kinase (PI3K). By analysing a mouse that lacked ARAP3, we were able to show that ARAP3, rather than the much better understood 'canonical' PI3K effector PKB/Akt is absolutely required in physiological angiogenesis. Moreover, we showed that ARAP3 is acting immediately downstream of PI3K to regulate angiogenesis, by developing and analysing a mouse in which ARAP3 carried a point mutation that uncoupled it from activation by PI3K. The point mutation mouse phenocopied the severe angiogenesis defect of ARAP3 deficient mice. We also provided evidence to further signalling events both up- and downstream of ARAP3.
Exploitation Route This work identified for the first time a PI3K effector that is absolutely required for physiological (developmental) angiogenesis. PI3K is known to also regulate pathological angiogenesis, where it is particularly important in cancer. Clinical trials are underway to block PI3K in cancer with a view to blocking angiogenesis, however, PI3K regulates a large number of processes unrelated to angiogenesis as well. Our work could be taken forward to characterise the role of ARAP3 in pathological angiogenesis. Inhibiting ARAP3 rather than PI3K might be advantageous since fewer side effects would be expected.
Sectors Healthcare,Pharmaceuticals and Medical Biotechnology

 
Description Our work on ARAP3 has been extended to analysis of angiogenesis in the zebrafish by others. Moreover, many groups have started to use a computational analysis tool of complex images of blood vessels that we developed (Angiotool).
First Year Of Impact 2010
Sector Digital/Communication/Information Technologies (including Software),Pharmaceuticals and Medical Biotechnology,Other
 
Description Project Grant
Amount £237,663 (GBP)
Funding ID PG/17/54/32981 
Organisation British Heart Foundation (BHF) 
Sector Charity/Non Profit
Country United Kingdom
Start 10/2017 
End 09/2020
 
Title Angiotool 
Description AngioTool is a software tool for quantitative analysis of microscopic images depicting complex vascular networks. To our knowledge there was no such tool available before. We published an open access article describing AngioTool to increase awareness in the scientific community (see papers) 
Type Of Material Data analysis technique 
Year Produced 2011 
Provided To Others? Yes  
Impact This software tool was made freely available to the public and was published as an open access research paper as well. It appears to be widely used in the research community and has been cited in numerous other research papers that use it for analysis of their vascular networks. 
URL https://ccrod.cancer.gov/confluence/display/ROB2/Home
 
Description International collaboration with NIH National Cancer Institute 
Organisation National Institutes of Health (NIH)
Department National Cancer Institute (NCI)
Country United States 
Sector Public 
PI Contribution The research pursued for this fellowship has resulted in an international collaboration which already led to publications in peer-reviewed journals.
Collaborator Contribution intellectual input
Impact two research papers and a book chapter
Start Year 2009
 
Description Press Release Science Signalling 
Form Of Engagement Activity A press release, press conference or response to a media enquiry/interview
Part Of Official Scheme? No
Geographic Reach International
Primary Audience Other academic audiences (collaborators, peers etc.)
Results and Impact Our recent Science Signaling paper was chosen for broadcasting by podcast by the editors of Science Signaling. After recording the interview, we also put together a press release, to co-incide with the paper appearing. We had further enquiries from several journalists. I understand the work was cited in some local papers and in 'Business Weekly'.

This has publicised our work more widely than the publication in a scientific journal alone would have.
Year(s) Of Engagement Activity 2010
URL http://stke.sciencemag.org/content/suppl/2010/10/22/3.145.pc19.DC1
 
Description Schools Open Day 
Form Of Engagement Activity Participation in an open day or visit at my research institution
Part Of Official Scheme? No
Geographic Reach Local
Primary Audience Schools
Results and Impact 10 GSCE / 'A'-level student came to the lab, listened to a short talk and participated in a hands-on practical experience.

Some of the students provided positive feed-back on the visit to the lab and said it had helped them with their career choice
Year(s) Of Engagement Activity 2008,2009,2010,2011