The zebrafish is a master of regeneration: If brain cells are lost due to injury or disease, it can simply reproduce them - contrary to humans where this only happens in the fetal stage. However, the zebrafish is evolutionarily related to humans and, thus, possesses the same brain cell types as humans. Can a hidden regeneration potential also be activated in humans? Are therapies for stroke, craniocerebral trauma and presently incurable diseases such as Alzheimer's and Parkinson's possible?
Dresden scientists have now succeeded in determining the number and type of newly formed neurons in zebrafish; practically conducting a “census” in their brains. Following an injury, zebrafish form new neurons in high numbers and integrate them into the nervous system, which is the reason for their amazing brain regeneration ability. The study is a true collaboration project “made in Dresden”: Scientists from the Center for Regenerative Therapies TU Dresden (CRTD) combined their expertise in stem cell biology with complex bio-informatic analyses from the Max Planck Institute for the Physics of Complex Systems (MPI-PKS) and the CSBD and with the latest sequencing methods from the DRESDEN-concept Genome Center.
For their study now published in Development, the team led by Christian Lange and Michael Brand from the CRTD used adult transgenic zebrafish in whose forebrain they were able to identify the newborn neurons. The forebrain of the zebrafish is the equivalent to the human cerebral cortex, the largest and functionally most important part of the brain. Together with the Steffen Rulands group at the MPI-PKS and the CSBD, the interdisciplinary research team investigated the newborn and mature neurons as well as brain stem cells using single cell sequencing. Thus, they discovered specific markers for newborn neurons and were able to comprehensively analyze which types of neurons are newly formed in the adult brain of the zebrafish. Together, researchers also investigated the data obtained from brain cells of mice and found that zebrafish and mice have the same cell types. This also makes these results highly relevant for humans.
"On the basis of this study, we will further investigate the regeneration processes that take place in zebrafish. In particular, we will study the formation of new neurons after traumatic brain damage and their integration," explains Michael Brand, CRTD Director and senior author of the study. "We hope to gain insights that are relevant for possible therapies helping people after injuries and strokes or suffering from neurodegenerative diseases. We already know that a certain regenerative ability is also present in humans and we are working on awakening this potential. The results of our study are also important for understanding the conditions under which transplanted neurons can network with the existing ones and thus could let humans re-gain their former mental performance.”
Christian Lange, Fabian Rost, Anja Machate, Susanne Reinhardt, Matthias Lesche, Anke Weber, Veronika Kuscha, Andreas Dahl, Steffen Rulands and Michael Brand: „Single cell sequencing of radial glia progeny reveals diversity of newborn neurons in the adult zebrafish brain”, Development 20 147, published 9 January 2020, doi: 10.1242/dev.185595