Journey to the Calleja Islands

The Calleja Islands were named after Julián Calleja y Sánchez, a Spaniard like many famous conquistadors, but neither a legendary pirate captain, nor even a simple navigator, sailor, or adventurer, and his fate was probably much more monotonous than that of Francis Drake, who was born some 300 years before him, who, though not called a conquistador, was an explorer, navigator, and English seaman for 55 and a half years of his life, second in the world in the fleet, but first in the world in captaincy, knighted, and as a lieutenant-major, a captain, a captain of the first ship to circumnavigate the globe, a captain of the first ship to sail in the wake of the raging storms and the wars of the Second World War. He played an active role in the destruction of the Spanish Invincible Armada. Despite his prodigious naval prowess, he is still known primarily by a name that not everyone would take as a compliment: the Pirate of Her Majesty Elizabeth I.
Philip II of Spain put a bounty of 20,000 ducats (now around £4 million) on the head of this pirate, which must have been quite a tribute, even if not many people would have wished for the same.

Julián Calleja y Sánchez was an anatomist, and it is not even known on the internet when he was born, but even if he spent much of his life in the dissecting room and laboratory, under the microscope, the anatomical formula named after him is far from boring or monotonous. To begin with, the paper that made Callaja's name famous, 'The olfactory region of the brain' - now known as the olfactory bulb (bulbus olfactorius) - was published in 1893, 10 years later than the German Sigbert Ganser's publication, which also discussed this structure. The real twist in the story, however, is that Calleja was looking at a different part of the olfactory bulb cell layer, and not the granule cells that bear its name today.

(Similar confusions and nomenclatural ambiguities do, of course, occur in the case of geographical discoveries. The Native Americans are called Indians because of Columbus's fallacy, and the continent is named after Vespucci, who was also Amerigo because, in the age of the Vikings, who long preceded both of them, such callings were not much in evidence.)

More important than the curiosity surrounding the naming of Calleja Island, however, is the fact of how the cell masses that then develop there into the granule cells known as Calleja Islands migrate along with the radial glial cells to the olfactory bulb, that the olfactory bulb itself is located in a very different way in the rodents most commonly used for experiments in vertebrates than in primates, since humans belong to this group and the main target of drug research is humans.

Perhaps this is enough to show that the story of exploration is also a great adventure, that there are many similarities between geographical and scientific discoveries, and that the discovery itself is never the end of the story, but the beginning of a perhaps even more exciting journey.

Here is an example of the work just published in Nature Communications, on which two teams worked literally shoulder to shoulder for five years. At the KOKI, it is the Molecular Neurobiology group of István Katona, and at the ELKH Natural Sciences Research Centre (NSC), it is the Medicinal Chemistry group of György Keserű MHAS. The protagonist of this story - and one of the first authors of the article published in Nature Communications - Suzanne Prokop, a Ph.D. student in István Katona's group, came to work during her August vacation because the reviewers of Nature Communications requested additional experiments for the submitted article.

- Congratulations on your achievements and the Nat. Comm. article! Since most of us are not familiar with either the super-resolution microscopy and other techniques used or the pitfalls of drug development, please summarize the essence of your discovery and development!

- There are a number of CNS drugs on the market for which many questions remain unanswered about the exact molecular mechanism of action. One reason for this is that we do not know exactly where the drug acts and which receptor in which cell. Our approach may help us to visualize individual receptor-ligand interactions in brain tissue at a much higher resolution and in a cell-specific way than has been possible so far. We have demonstrated the potential of our technology innovation using the example of the antipsychotic drug cariprazine.

- So the work is so complete that the results so far have had to be published, but the story is by no means over?

- The PharmacoSTORM project is far from being finished! The methodological development reported in this article can of course be improved and optimized, as is usually the case with research methods. I am confident that we will be able to answer many more pharmacological or biological questions with our approach.

- It will be exciting to see what drugs after cariprazine will be used to find out the mechanism of action of the drugs you develop! But the new method is only one part of the article. Your discovery is just as important.

- As well as technical innovations, the project has raised exciting biological questions. It has drawn our attention to a brain area called the Calleja Islands, about whose role we know very little.

- A work accepted for publication in Nature Communications, with two very significant results, is not common in the life of a researcher, and you are still at the beginning of your career!

- From the very beginning, I felt honored to work on this project and still do!

- Can you tell us what was the best part for you?

- One thing is hard to single out.
One of the most rewarding things for me was the opportunity to apply and deepen the knowledge I had previously acquired during my TDK work. As a student, I worked in the lab of László Hunyady (SE, Life Sciences), where I learned a lot about receptors and their methods of investigation. My Ph.D. project, which I started in István Katona's group, was also closely related to receptor pharmacology, and I feel that I was able to use my previous knowledge on receptor-ligand interactions in the PharmacoSTORM project. In the meantime, I have learned a lot about how the brain works and have acquired a lot of new techniques.

- You also had to work with another research team on this project.

- I have to mention this in particular, because working with György Keserű's chemistry group was fantastic! As a high school student, I was very interested in chemistry, physics, and mathematics, and every meeting brought back my old "childish" enthusiasm.

- I hope that this enthusiasm will continue, because without it one can be successful, but not "happy". However, experimental work is not only time-consuming, it cannot be done at home. How do you manage it?

- I am very lucky! Both at the institute and at home, I have received a lot of help in my work. Even if it sounds cliché, it's true: I couldn't have done it, or I wouldn't have done it without them. As far as the lab is concerned, I think the best way I can reciprocate is to try to teach the new students as much as possible and trust that my enthusiasm will rub off on them. I am especially happy that my TDK student Marci Vámosi was able to be an active part of the work!

- You have summarised for us the essence of the work published in this article. How would you sum up what this article and research, in general, mean to you?

- It was exciting to experiment with a drug whose clinical effects I myself have seen in patients. I have a very strong desire to understand exactly what other people's problems are and to help them. And I am very hopeful that my hard work in the grey every day will in some way really help in the future.

The achievement of this noble goal will not depend on Suzanne, as anyone who knows her can be sure. Fortunately, she has found a subject leader and a team where she can find her place and develop her talents.
I wonder what her supervisor and the last author of the article, István Katona, thinks is worth highlighting about the work and the article published?

- Above all, the study is the result of a very successful peer-to-peer collaboration based on trust. Without the team of academic and chemist György Bitter, we could not have started with our ideas! The idea itself was born at Christmas 2015 and is a beautiful example of how in modern life sciences, not everyone can be an expert in everything. It takes not only individual geniuses but also a trusting collaboration of top experts from different fields to achieve breakthrough results.

- By being one of the first authors of this article, Suzanne has highly fulfilled one of the most important requirements for a Ph.D. degree. How many Ph.D. students will she be?

- I just did the math! The experimental material for the eighth doctoral thesis has been completed in our KOKI workshop. What I'm very proud of is that all eight young people have had first-authored or shared first-authored articles published in Nature Index (2 Nat Neurosci, 2 Nat Comm, 1 Nat Prot, 3 J Neurosci). This shows that our workshop is an important stepping stone for young people, giving them the opportunity to achieve results early in their careers that can lead to significant international recognition. As both a former ERC (European Research Council) grant winner and a current ERC judge, I have found that a strong start in the doctoral period is a very important criterion for judging.

- And I remember when you were a TDK student in Tamás Freund's group! A lot has happened since then.

- On 22 October this year it was 28 years since I walked through the doors of KOKI. I was able to see with my own eyes how KOKI, under the leadership of Professor Vizi and Professor Freund, has become one of the world's leading institutes in the field of pharmacology and anatomy.
I am proud that our PharmacoSTORM method is a synthesis of their pharmacological and anatomical thinking, combining the strengths of both disciplines. It is likely that 28 years ago neither of them could have imagined that it would one day be possible to visualize and measure the binding of specific drug molecules in a cell-type and subcellular compartment (e.g. nerve terminal) in a specific manner in intact and complex neuronal networks. I hope they will be delighted to know that their work at KOKI has enabled this to be achieved for the first time in the world. I would also like to thank them for their unfailing confidence in me, which has enabled me to carry out my scientific and managerial work (e.g. the establishment of the Nikon Centre) in a supportive atmosphere.

- To wish that all students entering the Institute would achieve the same level of success as yours may be an exaggeration, but to wish that they would find their place and their mission seems to me to be absolutely the right wish.

- As a student entering a medical research institute and later as a researcher, I was often caught in a kind of cognitive dissonance. I think it is an instinctive inner expectation of all of us that the huge amount of work we invest in should benefit as many people as possible, and that it should be of social benefit beyond the interest of our colleagues in our field. This is, moreover, a legitimate expectation in a medical research institute that is essentially working with taxpayers' money.

- You are so right that it is now expected in tenders.

- It is often the case that we measure all sorts of interesting molecular, anatomical, and physiological parameters with lots of expensive instruments and chemicals, and then use these data to write elegant papers in highly prestigious journals. We are happy to see our work published in prestigious journals, to receive many citations from colleagues, and sometimes, of course, we even try to survive what Antal Szerb wittily wrote about in his novel The Legend of Pendragon, namely envy of success.
But it is very rare that our achievements are directly linked to the development of medical science. This study is a particular pleasure because I feel that there is a chance that it will be useful to my medical colleagues in the clinic.

- What are you thinking about in particular?

- Our results suggest that cariprazine binds in a hitherto little-studied brain area, the Calleja Islands, in the largest amounts, and that this binding pattern is significantly different from the binding pattern of the most commonly used antipsychotics and antidepressants. This may be very important for a rational understanding of the different therapeutic effects of cariprazine. This could include, for example, the amelioration of negative symptoms of schizophrenia spectrum disorder, for which other antipsychotics are currently not suitable.
This is why I am hopeful that our study will lead many colleagues to join us and start to investigate in detail the role of Callejasins in the human brain and in psychiatric disorders.

Finally, I would like to emphasize how special it is to have contributed to the understanding of the neurological mechanism of action of a drug of industrial historical importance developed in Hungary.