Stem cell transplants are widely used in various therapies and clinical trials for their therapeutic potential against a number of medical conditions. The heamaopoietic stem cells are capable of recreating and sustaining an entire blood system in humans, thus used for bone marrow transplants. These blood stem cells can be transplanted from the donor to the patient but their working and transition remained unclear.
Dr. Leonard Zon and his colleagues at Boston Children’s Hospital’s Stem Cell Research Program used time-lapse imaging and colour dyed stem cells to uncover the working of stem cells in Zebra fish which closely resembles the human stem cell system. Their study was published in the last month scientific journal, Cell. The findings of this research on zebra fish provide a reliable model to understand the human stem cells. Dr Zon said, “The same process occurs during a bone marrow transplant as occurs in the body naturally”. It gives access to specific treatment options for bone marrow cancer, blood and severe immune disorders.
How it works?
The stem cells in the bone marrow create blood but how these stem cells move from their place of origin and mature is unknown. According to the study, the blood stem cells reach the blood cell formation site and binds with the growth factors of blood vessel cells using receptors. While the chemical signal instructs these stem cells to push through to the other side, it reaches the niche. In the niche, the stem cells get attached to other cells like endothelial cells of blood vessel which cuddles with them. This cuddling keeps the stem cells stay attached with the nurse cells aka stromal cells until they divide and begin the whole process all over again. This process repeats in various niches till the desired location is densely populated with stem cells.
Working Model of Zebrafish
Here, Zon and his team developed a transparent model of zebrafish to study its embryonic development. They dyed the blood stem cell system into green and using confocal and electron microscope, tracked their movement in the niche to study the missing steps. Further experiments showed that the process observed in zebrafish closely resembles the process of mice. This opens possibilities for the existence of the same blood system in humans too. During the experiment, the scientists discovered a chemical compound called ‘Lycorine’ that enhances the interaction between the stem cells and its niche, thereby promoting the increase of blood stem cells. This will help to improve the success of bone marrow transplant.
Zon in a statement, “Our direct visualization gives us a series of steps to target, and in theory we can look for drugs that affect every step of that process”.