THE
BIOMEDICAL SCIENTIST
ISSUE #1 / BMSC201
Dr. Subhra Hui on Zebrafish regeneration
CONTENTS 3
FROM THE WRITERS
4
INTRODUCTION
5 DR. SUBHRA HUI ON HEART REGENERATION AND MORE
FROM THE WRITERS SEDRICX FONTANILLA COREY ROBINSON
We were tasked to find a researcher to be interviewed regarding their field of expertise. Our Lecturer in charge Nancy Mckenzie advised us to look into the Victor Chang Cardiac Research institute. We found a research about the Heart regeneration of the zebrafish and this caught our attention so we asked our lecturer in charge if we can interview the head of the research Dr. Kazu Kikuchi. Unfortunately, Dr. Kazu Kikuchi wasn’t available at that time but luckily, Dr. Subhra Hui which is a part of the research was able to entertain us with an interview. The interview went smoothly and we were even given a rare glimpse of the research that they are conducting. We were toured around the laboratory and showed us the different complex equipment housed inside the Victor Chang building. We were also able to view where they breed and test the zebrafish. Before the interview started, Dr. Subhra Hui emphasized that the whole interview is only for academic use and shouldn’t be published commercially. With that said, this “mini-magazine” is published only for the purpose of the completion of a requirement in BMSC201 (Communicating ideas in science), the contents of this “mini-magazine” cannot be used outside the ACU.
We hope that you’ll have a great time reading our interview with Dr. Subhra Hui about the Zebrafish heart regeneration and more.
INTRODUCTION
DR. SUBHRA HUI
POST-DOCTORAL RESEARCH SCIENTIST
“WHEN I CAME TO THE PHD TO DO MY DOCTOR IN STUDIES, I FOUND THIS FISH, NOT ONLY THE ZEBRAFISH, ANIMALS IN THE ANIMAL KINGDOM HAS THE SPECIAL ABILITY TO NATURALLY REGENERATE THEIR BODY PARTS”
ZEBRAFISH REGENERATION AND MORE How did you come up with your hypothesis? Well, I was studying zoology in my masters and its where I became fascinated with animal biology and the life of animals. When I came to my PhD I found this fish (not only the zebrafish, but other animals in the animal kingdom) have the special ability to regenerate their body parts. So, if they were to lose one of their body parts, they are able to naturally regenerate it. There are similar animals like the starfish, for when they lose an arm, they can steadily regenerate it. Also, the Mexican Salamander can naturally regenerate their tail. However, the zebrafish is seen as the model organism, because now we have the molecular tools and their genomic sequence is 80% similar to humans.
These fish are very small and easily managed in the lab, in regards to temperature and breeding, so there isn't much need for special care. These fish are transparent from birth, so the development of body parts is easily tracked using our technology.
“The genomic sequence is more or less 80% similar to humans� The zebrafish have the ability to regenerate several types of fins (similar to a human's legs), cardiac muscle, spinal cord, central nervous system, kidney pancreas and liver. All of these parts of interest are all in the one organism, meaning the zebrafish is the ideal model when researching cell regeneration.
What are the main advantages of using the zebrafish? Because zebrafish are transparent from birth, you can label each and every cell in the zebrafish embryo. And because of this transparency you can just track them. Sort of like our whole brain for example, it has all been developed from just one cell and as we grow, millions of cells form. So, we can start at this one cell and label them and see from two or three days how they are growing and developing. This procedure is impossible in humans or mice because they are not transparent, but thanks to technology, we have the ability to study this in the zebrafish which is not normally possible in other model organisms.
“zebrafish are transparent from birth�
How did you come up with your hypothesis? Well, I was studying zoology in my masters and its where I became fascinated with animal biology and the life of animals. When I came to my PhD I found
Do you find it hard experimenting on the zebrafish underwater? No, of course not. We have all kinds of experimental procedures because to cause the regeneration we have to cut or amputate some organs, just like if you want to study cardiac regeneration you have to amputate some part of the muscle. We usually use two kinds of injury models. The first is amputation, so just cut the muscle and remove 20%. And the other method is cryo-injury using the cryoprobe. This is a copper node that emits a cold stream of gas that burns and cuts anything it touches. But, first before we use either method we have to anesthetize the fish. We have special anaesthetics for
the aquatic environment we lower the fish respiration, similar to human surgery. Here, at the institute we have very good facilities, we can keep 15 fish in a small 3 litre tank. We do this because we need to study different strains of fish. In our facility we have more than 200 different strains of fish and we need to maintain them all separately for experimental purpose. All our standard protocol has now been established so now the facility is much more efficient.
What kinds of problems have you encountered with this research?
So, the zebrafish aren’t very similar to humans, so we are not doing clinical applications. So, whatever knowledge we gain from the zebrafish fish, regarding cell and tissue regeneration, we believe we can translate these techniques or findings into the human, because the human to some extent, can regenerate. Through the information behind this model organism, we can of course apply, because now regenerative medicine and stem cell research is a new field of human science and biomedical science application. But the problem is, because what we are doing is considered a basic science, so funding is always less compared to the clinical science areas involved in the applications. We are having some funding problems recently, but now were are in a sound position because we can do some more application work in zebrafish other than human.
What are your current findings in this research? Well, recently in our studies we have found that the zebrafish possess some stem cells in their tissues and that’s the big advantage from humans and mammals. But, in some other injuries, there’s some other cells moving to the site. Immune cells will come to the site along with white blood cells, so we are interested to discover whether immune cells hold some role in this process. No one has studied this area concerning regeneration before so we started a project concerning all the immune cells coming to the injury site to study them one by one to discover if they hold any purpose in the regenerative process. Recently, I have found that one of the immune cells called the regulatory T cell has regenerative roles to help the tissue repair process. This was not known before. Regulatory T cells are also studied in humans, but no one has yet discovered if they hold a similar characteristic. But, if we genetically ablate these cell types in fish during the regeneration process, the regeneration does not happen, it’s impaired. This directly means that these regulatory T cells have immense importance to the regenerative process. These are very good findings, so were are thinking about publishing this study very soon.