What GCRF START means for my research on human papillomavirus (HPV) 16 pseudovirions

“I think we, as African scientists, have a lot to offer. We are very connected and very close to the problems of the world. On a daily basis, we witness many of the global challenges first-hand and see the impact of diseases like HIV/AIDS, TB, Malaria, cancers and other communicable, as well as non-communicable diseases. We can see directly how our research can be life-saving. This is a big motivator!” 

Melissa Marx, University of Cape Town, South Africa 

To me, the GCRF START grant means the ability to learn new techniques which I can apply in my research on the human papillomavirus (HPV) 16 pseudovirions (PsVs) at the University of Cape Town (UCT). I’m using the structural biology technique cryo-electron microscopy (cryo-EM) to image HPV16-PsVs particles in order to obtain a better idea of the entry mechanisms used by the virus to infect host cells. With the help of the START grant, I can use techniques for research that could potentially contribute to the development of inhibitors for HPV infection, thereby decreasing HPV-associated cancer incidence down the line. This is really exciting and topical because cervical cancer – almost always caused by oncogenic HPV infection – is one of the most common cancers in women globally and the HPV is the second most frequent cause of cancer among women in Africa and in my own country of South Africa. My research and the START grant are therefore very important to me personally, as well as for women in Africa in general.  

As a ‘newbie scientist’ in the early stages of my career, it is important to be exposed to different techniques that we wouldn’t normally be exposed to here in Africa. In my undergraduate degree, I had almost no exposure to electron microscopy and computer software in general. Fast forward to the present as a first year MSc student, and after only one year of experience in this field (and lots of help), I’ve managed to make three reconstructions of HPV particles using two different reconstruction programs and have made large numbers of grids on which we mount the samples! Within South Africa, there isn’t a lot of information about cryo-EM and other techniques we need to use for our research. Through the grant, I have been able to learn things like negative staining, vitrification, sample purification, sample preparation, and data analysis using RELION, and I even had the opportunity to go overseas to visit the UK’s national synchrotron, Diamond Light Source (Diamond). 

Why developing Inhibitors for HPV could be the way forward 

“Melissa’s project is the result of a fruitful collaboration with the Electron Microscopy Unit at the University of Cape Town which adds exciting new approaches to study and target viral entry mechanisms.” 

Dr Georgia Schäfer, University of Cape Town, South Africa 

Human Papillomavirus (HPV) is one of the most commonly diagnosed sexually transmitted viruses worldwide, and infection with high risk types has been linked to several cancer types, most notably cervical cancer, as mentioned above. In Africa, an estimated 372.2 million women aged 15 years and older are at risk of developing cervical cancer; every year, 119,284 women across Africa are diagnosed with cervical cancer and 81,687 women die from the disease, as reported by the HPV Centre report on HPV in Africa, 2019.  In my own country of South Africa, cervical cancer is the first most common female cancer in women aged 15 to 44 years and one of the leading causes of cancer related deaths [1-6]. Although HPV vaccinations exist and are safe, these vaccines are only protective to HPV uninfected adolescents, making them ineffective for persons already infected with HPV [7,8].  

The vaccines are also relatively expensive and need repeat doses [7,9,10]. This creates a difficult situation for many people, who may not be able to afford repeat treatments or do not have easy access to health care facilities. In addition, rural communities in South Africa are largely unaware of HPV infection as a risk factor for cervical cancer, which has made vaccine distribution ineffective, with little of the South African population vaccinated between 2009 and 2014 [11]. Developing medication to prevent HPV infection by blocking the entry of HPV into susceptible human cells could be an alternative to vaccination, and another opportunity to reduce the amount of HPV associated cancers within South Africa and worldwide.  

In our laboratories at the University of Cape Town we have identified two human proteins, surfactant protein A (SP-A) and vimentin, which decrease HPV infection by modulating viral entry into susceptible cells [12] or by activating the innate immune system, respectively. This research took place in UCT’s Electron Microscope Unit at the Aaron Klug Centre for Imaging and Analysis and Division of Medical Biochemistry and Structural Biology (Institute of Infectious Disease and Molecular Medicine). To determine which portions of these two proteins interact with HPV, electron microscopy imaging and 3D reconstruction studies of HPV particles pre-incubated with each of these two proteins are being conducted. From this, and further biochemical tests, we can determine the relevance of these interactions for HPV infection, with the potential to develop inhibitors for HPV infection of susceptible human cells.  

Using Diamond Light Source synchrotron to image our HPV samples 

In order to carry out this research access to state-of-the-art imaging equipment is vital. The GCRF START grant has made this possible, by providing our researchers and collaborators with access to the Electron Bio-imaging Centre (eBIC) embedded at Diamond Light Source.  My visit to the Diamond synchrotron to conduct experiments for my research took place from the 9 – 11 October 2019. We had done the sample preparation at the University of Cape Town and had shipped the HPV samples in liquid nitrogen to Diamond a few weeks previously, so they were there once we arrived. The HPV samples were loaded onto the Diamond M06 Titan Krios electron microscope with the help of eBIC staff before imaging them using the transmission electron microscopy (TEM) technique. 

Unfortunately, there are no equivalent facilities available on the African continent, and only a handful available worldwide, so I feel unbelievably fortunate to have been to Diamond – not just as someone from overseas on a tour but to have the experience as a researcher of working in and around such an innovative environment. The research and the equipment available are cutting edge and incredibly motivating to a young scientist. In addition to this, the scientists and staff are friendly and easy to engage with, and I found myself having conversations with researchers from all fields, not just biology.  

Having a central research hub with scientists from different academic backgrounds, such as the materials sciences, biology, physical sciences, chemistry and others, creates a co-operative space and is likely to benefit anyone who participates. Being at Diamond Light Source and the Harwell Campus made me realise that having such a research hub is essential to science, aside from making things easier logistically! It was an incredible experience to be at Diamond Light Source, and I don’t think I could thank everyone involved enough for all the support and guidance along the way.  

 Acknowledgements  

Most importantly, I would like to thank Dr Jeremy Woodward, who is a GCRF START Co-Investigator – for the time and effort he was willing to put into this project; I really wouldn’t be anywhere without him. I am also grateful to my supervisor, Dr Georgia Schäfer, for her help and encouragement, especially when producing the HPV16 particles at such short notice! I am also grateful to GCRF START Co-Investigator, Prof. Trevor Sewell, and Dr Andani Mulelu (previously a GCRF START-funded Postdoctoral Research Fellow), and to Dr Lubbe (currently a START-funded Postdoctoral Research Assistant); thanks also to Dr Sarron for all the advice and reassurance – which really helps! Lastly, I would like to thank the staff of the Electron Microscopy Unit at the University of Cape Town, especially Mohammed Jaffer, and the eBIC staff – James Gilchrist and Alistair Siebert – all of whom were very cheerful and accommodating when using the different microscopes. I even had a good enough sample for me to travel to Diamond, with the help of my two brilliant supervisors, Dr Georgia Schafer and Dr Jeremy Woodward, without whom, I might have been completely lost!  

My science career so far.. 

I’ve always had an interest in biology, and I was fortunate enough to have parents who encouraged my interest, although they didn’t always know what I was doing! I began my scientific journey by completing a Bachelor of Science at Stellenbosch University (South Africa) in biochemistry and physiology. I then moved to the University of Cape Town for my Honour’s and Masters’ degrees. I was exposed to structural biology during my Honour’s degree, but I was somewhat intimidated by all the physics and maths involved. So, I only became involved in structural biology during the first year of my Master’s degree, at the Biophysics and Structural Biology at Synchrotrons 2019 conference (Cape Town, South Africa). I am currently completing my MSc in Medical Biochemistry and Structural Biology, under the supervision of Dr Georgia Schäfer and Dr Jeremy Woodward, within the Electron Microscopy Unit at UCT.