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Christine Goffinet: independent and successful AIDS researchers

Christine Goffinet, 36, from the Institute of Molecular Virology at the University of Ulm has already received numerous awards for her research on AIDS. She was recently awarded a scholarship for postdoctoral lecture qualification under the Margarete von Wrangell Habilitation Programme. However, before she became a virologist, Goffinet chose a career path that was quite different from the standard career path seen on many scientific CVs.

AIDS researcher Dr. Christine Goffinet. © University of Ulm

After finishing high school, Christine Goffinet, originally from Brittany in France, did not want to continue studying. She was more interested in working with people than theoretical studies. So she decided to do hotel management training, which she enjoyed tremendously. She is still not really sure why she eventually got involved in the life sciences. However one thing she is sure of is that, as she says “if I had not trained in hotel management, I would not be here.” Here is the laboratories of the life sciences building on the Oberer Eselsberg campus of Ulm University.

Lack of career prospects in the hotel business and the repetitive daily routine are what pushed Christine Goffinet towards her “second love”, biology, and she has been working in this field ever since. Her interest in the sciences was really ignited when she did her degree thesis on immunology at the University of Hamburg, which she finished in 2003. Christine Goffinet had found her life’s calling, in fact she was infected by the ‘science virus’. However, it was not until she began working in the laboratory of Oliver Keppler (now in Frankfurt) that she was introduced to AIDS research; she stayed in this laboratory until autumn 2010.

Her doctoral thesis obtains the first of several awards

During her doctoral studies (“that’s where my love for science really flourished”), Goffinet turned to the holy grail of AIDS research, i.e. a small-animal model for HIV infection, which is still of paramount importance for vaccination studies and antiviral therapies. Her supervisor, Prof. Keppler, and his team had already carried out preliminary studies on HIV-susceptible transgenic rats that expressed HIV receptor and co-receptor complexes on relevant immune cells. In 2007, Goffinet and Keppler (now at the University of Frankfurt; Department of Medical Virology) received the AIDS Research Award from the German Society for Infectiology for their small-animal HIV model. This transgenic rat model enabled the researchers to study the early steps in the HIV replication cycle and test therapeutic molecules (e.g. fusion inhibitors, integrase inhibitors) that target this phase in rodents. Previously, such tests could only be carried out using non-human primates, which were extremely complex, time-consuming and ethically highly controversial.

Goffinet continued her postdoctoral research activities in Heidelberg, but turned to a different topic, namely tetherin. Tetherin is a protein that is part of the interferon-dependent antiviral response pathway and had just been shown to inhibit the spread of HIV-1 by reducing the infectiousness of newly formed viruses (2008; doi: 10.1038/nature06553). Moreover, the protein was starting to become a research subject where science laurels could be earned. Tetherin belongs to restriction factors that are associated with HIV disease progression. Researchers presume that humans possess several hundred of these antiviral proteins; however, at present only a handful of these virus inhibitors are known. The majority are unknown because their antiviral effect remains enigmatic. These inhibitors only come to light when their viral antagonist is switched off, for example by using virus mutants that do not express this particular antagonist. Moreover, this can only be done if evidence is available for the potential antiviral effect of a protein of interest.

A tumour-associated protein turns out to be a potential HIV inhibitor

90K is an interferon-dependent protein: fluorescence-based detection in primary macrophages. Top photo: without IFN-alpha; bottom photo: exposed to IFN-alpha. © Goffinet

Since November 2010, Christine Goffinet, now married with one daughter, has been head of an independent junior research group at the Institute of Molecular Virology at the University of Ulm. Her research is focussed on the characterisation of the antiviral properties of IFN (interferon)-stimulated genes. Her new preferred research object is the tumour-associated protein 90K, for which she was awarded a Margarete von Wrangell habilitation grant in 2012 and started working on in early March 2013. 

Goffinet discovered 90K using an extremely simplified screening procedure by limiting her search for antiviral proteins to two typical features, i.e. interferon induction and the elevated expression of the proteins in HIV patients. Her screening procedure led to the detection of the protein 90K, which was one of four most promising proteins. “I must admit that I was quite lucky. I am not a fan of large-scale screens,” Goffinet explained. 

Goffinet was able to base her investigations on knowledge obtained in previous studies: 90K is encoded by a tumour-associated gene and was initially discovered in the serum of cancer patients. It is a widely expressed secreted glycoprotein and is therefore not only found in cells, but also in blood and other body fluids like tears, breast milk and semen. 90K is easy to detect and is found at elevated levels in patients infected with human immunodeficiency virus, both on the protein and the mRNA level. 90K is highly glycosylated, interferon-dependent and is around 600 amino acids long. 

The name of the protein is derived from its molecular weight of 90 kDa, but it is also known as LGALS3BP (galectin-3-binding protein). The human protein belongs to the galectins, a family of beta-galactoside-binding proteins implicated in modulating cell-cell and cell-matrix interactions (National Center for Biotechnology, https://www.gesundheitsindustrie-bw.dewww.ncbi.nlm.nih.gov/gene/3959, information as of 9th June 2013).

The long and successful path to finding evidence

90K – a new restriction factor that is being characterised by Christine Goffinet. 90K has an antiviral effect and makes viruses less infectious. © Goffinet

Christine Goffinet carried out cell culture studies which provided strong evidence for the antiviral effect of the 90K protein. The introduction of a proviral HIV plasmid into a human cell line that did not express 90K led to the expression of 90K. These results showed that she was on the right track: although viruses were produced, their infectiveness was so low that they could not infect new cells. To substantiate this finding, Goffinet carried out a reverse experiment with a cell line that expressed the 90K protein, but whose expression could be suppressed using siRNA. The result confirmed Goffinet’s assumption that the viruses became infectious again in cells that lacked the 90K protein. The investigation of the viruses in the supernatant showed that the antiviral effect of 90K was due to the defective assembly of a viral envelope protein.

Following this important finding, Goffinet carried out mutation studies with the aim of identifying the 90K domains that were relevant for the antiviral effect of the protein. She has since found that the expression of the central two of the four domains was sufficient to generate the protein’s antiviral effect. She will carry out further mutation studies to specifically identify the regions with antiviral activity. This will create the basis for the synthesis of a therapeutic peptide or small molecule drugs. Species comparisons might further accelerate Goffinet’s work as the human 90K protein has a high amino acid similarity with the protein counterpart in rhesus monkeys. Goffinet hopes that the identification of the small number of differences between the human and monkey amino acid sequences will help her identify the amino acids responsible for the protein’s antiviral effect.

90K has a viral antagonist

Meanwhile, there is growing evidence that Goffinet’s 90K studies are on the right track. Initial studies with isolated blood macrophages, which are among the first cells infected by HIV-1, have confirmed the antiviral effect of 90K and the researchers have been able to exclude potential artificial effects of the initial cell line experiments. At present, studies are underway with CD4-expressing cells, which are used by HIV-1 to enter into host T-cells and a major focus of HIV-1 research.

The discovery of a 90K antagonist in HIV would confirm the importance of this protein in the immune defense against HI viruses. Every known restriction factor has an antagonist; HIV has accessory proteins such as vif, vpu and nev that act as antagonists to 90K. The protein vif was discovered around 10 years ago. Goffinet’s research has since come up with evidence for the presence of viral 90K antagonists, but she is unable to disclose more as the findings are currently being prepared for publication.

At present, Goffinet’s data are only of a functional nature. She does not yet know the deceptive counter-strategies that HIV uses to protect itself against the antiviral 90K protein. In-depth insights into the antagonism need to be gained before Goffinet is able to develop an artificial 90K protein that is sufficiently small, antagonism-resistant and has a long half-life and excellent pharmacokinetics. And this will take quite some time. However, she believes that a combination of antiviral inhibitors will be required for turning off the viral antagonists, rather than just a single, artificially modified restriction factor.

"I prefer to discover things and work on many different topics”

Christine Goffinet is not a researcher who wants to spend her entire career on a single molecule. “I prefer constantly discovering new things and working on different molecules and topics,” Goffinet admitted. However, few funding agencies and investors find the idea of frequently changing topics as appealing as some scientists do; they prefer to spend money on projects whose results are basically already known. “It would probably have been easier to stay with one topic,” says the researcher. However, her preference for working on different topics was also the reason for moving to Ulm. “I have always wanted to remain independent, always try new things.”

So it comes as no surprise that she is also driving another AIDS research project forward: she has observed that the fusion of the HI virus with the infected cell membrane is all that is needed by the cell to realise that it has been infected and that it needs to switch on interferon-dependent immune responses. She has been able to substantiate her observation with cell-cell fusion assays.

The Margarete von Wrangell habilitation grant will support her research into the antiviral 90K protein for five years. At the institute of the renowned AIDS researcher Frank Kirchhoff, Goffinet has the freedom she wants to carry out independent research projects. After her habilitation, she hopes that she will be able to move up the academic career ladder and become full professor. Then, she will probably be one of only a handful of former hotel managers with the prospect of obtaining the highest possible academic degree.

Website address: https://www.gesundheitsindustrie-bw.de/en/article/news/christine-goffinet-independent-and-successful-aids-researchers