BIOTEC - Biotechnology Center TU Dresden

A fundamental problem in neurobiology is how the multitude of different cells of the brain are generated from their precursors, or stem cells. We study the underlying mechanisms during vertebrate brain development and regeneration. We ask, for instance, how neural stem cells give rise to and maintain the adult brain, during normal homeostasis and during regeneration of the brain. Because zebrafish have a spectacular ability to regenerate and well developed genetics and molecular biology tools, they are particularly well-suited for these studies.

We studied how embryonic neural precursor cells at the border between midbrain and hindbrain (MHB) act as organizers of cell fate onto the surrounding cells, which eventually form the midbrain and cerebellum, and which signals determine where the MHB organizer forms initially. The signaling molecule Fgf8 is absolutely required for MHB organizing activity. For instance, zebrafish acerebellar mutants have no functional Fgf8, and hence lack a cerebellum and proper polarity in the midbrain. In genetic, cell biological and biophysical studies, we study how secreted Fgf signals exert their function at the MHB and in other embryonic organizer cell populations, and how Fgf gradients form in the embryonic neural primordium (left panel).

We also study organizer-associated signaling molecules in the adult brain. In contrast to mammals, adult zebrafish brains retain an amazing number of active neural stem cells throughout, in very discrete spatial domains (right panel). Numerous new neurons of different subtypes are produced in the adult zebrafish brain, providing an ideal genetically and experimentally tractable system for understanding brain repair processes. Using CNS lesion paradigms, transgenics and Cre-loxP technology, we ask by genome-wide methods what controls the ability of adult neural stem cells to repair damage. Stem cell based regeneration studies in fish may thus provide clues how CNS regeneration can be stimulated also in mammalian brains.

A stable morphogen gradient of Fgf8 forms in a developing multicellular organism by a simple mechanism, involving a localized source, single molecule Brownian diffusion through the extracellular space and restrictive clearance from the extracellular space via endocytosis (from Yu et al., Nature 2009).	While in mammalian brains, new neurons are produced in only two small subdivisions, new neurons are generated throughout the regenerating adult zebrafish brain (Grandel et al, Dev Bio 2006; Kaslin et al, J. Neurosci 2009).

• organizer-dependent patterning and differention processes in the embryonic and adult vertebrate brain
• understanding stem cell activity and control in the adult CNS of a regenerating vertebrate

2011
Kizil C, Brand M (2011) Cerebroventricular Microinjection (CVMI) into Adult Zebrafish Brain Is an Efficient Misexpression Method for Forebrain Ventricular Cells. PLoS ONE 6(11): e27395. doi:10.1371/journal.pone.0027395

Volker Kroehne, Dorian Freudenreich, Stefan Hans, Jan Kaslin and Michael Brand (2011). Regeneration of the adult zebrafish brain from neurogenic radial glia-type progenitors. Development 138, in press.

Ganz J, Kaslin J, Freudenreich D, Machate A, Geffarth M, Brand M.: Subdivisions of the adult zebrafish subpallium by molecular marker analysis. J Comp Neurol. 2011 Aug 19. doi: 10.1002/cne.22757. [Epub ahead of print]

Nowak, M., Yu, Shuizi Rachel, Gupta, Mansi, Machate, Anja and Brand, Michael (2011): Interpretation of the Fgf8 morphogen gradient is regulated by endocytic trafficking. Nature Cell Biology 13(2):153-158.

Knopf, Franziska, Christina Hammond, Avinash Chekuru, Thomas Kurth, Stefan Hans, Christopher W. Weber, Gina Mahatma, Shannon Fisher, Michael Brand, Stefan Schulte-Merker and Gilbert Weidinger (2011). Bone regenerates via dedifferentiation of osteoblasts in the zebrafish fin. Dev. Cell, 17;20(5):713-724.

Boldajipour, Bijan, Katsiaryna Tarbaschevicha, Maria Doitsidou, Cedric Laguric, Rachel Shuizu Yu, Jonas Riese, Karin Dumstreib, Julia Dörriesb, Esther-Maria Messerschmidta, Petra Schwille, Michael Brand, Hugues Lortat-Jacobc, Erez Raz (2011). A role for biased receptor recognition in chemokine subfunctionalization and evolution. Development 138, in press.

Kizil C, Kaslin J, Kroehne V, Brand M (2011). Adult neurogenesis and brain regeneration in zebrafish. Dev Neurobiol. 2011 May 18. doi: 10.1002/dneu.20918.

Jászai, József,  Christine A. Fargeas, Sylvi Graupner, Elly M. Tanaka, Michael Brand, Wieland B. Huttner and Denis Corbeil (2011). Distinct and conserved prominin-1/CD133?positive retinal cell populations identified across species. PLoS One, 6(3):e17590.

Dahmann, C, Oates, AC, Brand, M (2011) Boundary formation and maintenance in tissue development. Nature Review Genetics, 12(1):43-55.

Grandel, H. and Brand, M. (2011). Zebrafish limb development is triggered by a retinoic acid signal during gastrulation. Developmental Dynamics. 240(5):1116-1126.

Hans, S., Freudenreich, D., Geffarth, M., Kaslin, J., Machate, A. and  Michael Brand (2011). Generation of a non-leaky heat shock-inducible Cre line for conditional Cre/lox strategies in zebrafish. Developmental Dynamics 240(1):108-115.

Winkler, S., Gscheidel, N., Brand, M. (2011). Mutant generation in vertebrate model organisms by TILLING. In: Vertebrate Embryogenesis: Methods and Protocols, Methods in Molecular Biology Series. In press.

2010
Ganz J., Kaslin J., Hochmann S., Freudenreich D., Brand M. (2010) Heterogeneity and Fgf dependence of adult neural progenitors in the zebrafish telencephalon. GLIA, 58(11):1345-1363

Antos, Christopher L; and Brand, Michael (2010) Regeneration of Organs and Appendages in Zebrafish: A Window into Underlying Control Mechanisms. In: Encyclopedia of Life Sciences, John Wiley & Sons, Ltd: Chichester http://www.els.net/ [DOI: 10.1002/9780470015902.a0022101]

2009
Picker A, Cavodeassi F, Machate A, Bernauer S, Hans S, Abe G, Kawakami K, Wilson SW, Brand M. (2009) Dynamic coupling of pattern formation and morphogenesis in the developing vertebrate retina. PLoS Biol. Epub 2009 Oct 13.

Yu, S.R., Burkhardt, M., Nowak, M., Ries, J., Petrá?ek, Z., Scholpp, S., Schwille, P. and Brand, M. (2009). FGF8 morphogen gradient is formed by a source-sink mechanism with freely-diffusing molecules. Nature, Sep 24;461(7263):533-6

Ries, J. , Yu, S. R., Burkhardt, M., Brand, M. and Schwille, P. (2009). Modular scanning FCS quantifies ligand-receptor interactions in live multicellular organisms. Nature Methods, Aug 2. PMID: 19648917.

Rhinn M, Lun K, Ahrendt R, Geffarth M, Brand M. (2009) Zebrafish gbx1 refines the midbrain-hindbrain boundary border and mediates the Wnt8 posteriorization signal. Neural Dev. 2009 Apr 2;4:12.

Kaslin, J., Ganz, J., Geffarth, M., Grandel, H., Hans, S. and Brand M. (2009). Stem Cells in the Adult Zebrafish Cerebellum: Initiation and Maintenance of a Novel Stem Cell Niche. J Neuroscience, May 13;29(19):6142-53. PMID: 19439592 [PubMed - in process]

Picker A, Roellig D, Pourquié O, Oates AC, Brand M. (2009) Tissue micromanipulation in zebrafish embryos. Methods Mol Biol. 546:153-72.

Hans, S., Kaslin, J., Freudenreich, D., and Brand, M. (2009). Temporally-controlled Site-specific Recombination in Zebrafish. PLoS ONE. 2009;4(2):e4640. Epub 2009 Feb 27.

2008
Schenck, A., Goto-Silva, L., Collinet, C., Rhinn, M., Giner, A., Habermann, B., Brand, M. and Zerial, M. (2008). The endosomal protein APPL1 mediates Akt substrate specificity and cell survival in vertebrate development. Cell. 2008 May 2;133(3):399-400.

Kaslin J, Ganz J, Brand M. (2008). Proliferation, neurogenesis and regeneration in the non-mammalian vertebrate brain. Philos Trans R Soc Lond B Biol Sci. 29;363 (1489):101-122.

2007
Scholpp, S. and Brand, M. (2007) Regionalisation of the neural tube: a balance between organizers and competence fields. New Encyclopedia for Neuroscience 2007, Ed. Larry Squire, UCSD School of Medicine, USA.

Wendl T, Adzic D, Schoenebeck JJ, Scholpp S, Brand M, Yelon D, Rohr KB. (2007). Early developmental specification of the thyroid gland depends on han-expressing surrounding tissue and on FGF signals. Development 134(15):2871-2879.

Erickson, T., Scholpp, S., Brand, M., Moens, C. B., and Waskiewicz, A. J. (2007). Pbx proteins cooperate with Engrailed to pattern the diencephalon-midbrain boundary. Developmental Biology 301, 504-517.

Funfak, A. Brösing, A., Brand, M. and Köhler, J.M. (2007). Micro-fluid segment technique for screening and development studies on Danio rerio embryos. Royal Soc Chemistry LOC, 7(9):1132-1138.

Erickson, T., Scholpp, S., Brand, M., Moens, C. B., and Waskiewicz, A. J. (2007). Pbx proteins cooperate with Engrailed to pattern the diencephalon-midbrain boundary. Developmental Biology, Jan 15;301(2):504-17. doi: 10.1016/j.ydbio.2006.08.022

2006
Grandel, H., Kaslin, J., Ganz, J., Wenzel, I., and Brand, M. (2006). Neural stem cells and neurogenesis in the adult zebrafish brain: origin, proliferation dynamics, migration and cell fate. Developmental Biology, 295(1):263-277.

Reim, G., and Brand, M. (2006). Maternal control of vertebrate dorso-ventral axis formation and epiboly by the POU domain protein Spg/Pou2/Oct4. Development, 133(14):2757-2770.

Scholpp, S., Wolff, O. , Brand, M. and Lumsden, A. (2006). Hedgehog signalling from the Zona Limitans Intrathalamica orchestrates differentiation of the zebrafish diencephalon. Development 133, 855-864.

Rhinn, M., Picker, A., and Brand, M. (2006). Global and local mechanisms of forebrain and midbrain patterning. Curr Opin Neurobiology 16, 1-8.

Langenberg, T., Dracz, T., Oates, A.C., Heisenberg, C.P. and Brand, M. (2006): Analysis and visualization of cell movement in the developing zebrafish brain. Developmental Dynamics, 235(4); 928-933.

Scholpp, S. and Brand, M. (2006) Regionalisation of the neural tube: a balance between organizers and competence fields. New Encyclopedia for Neuroscience 2007, Ed. Larry Squire, UCSD School of Medicine, USA. Submitted.

2005
Picker, A. and Brand, M. (2005): Fgf-signals from a novel signaling center determine axial patterning of the prospective neural retina. Development 132 (22):4951-4962

Rhinn, M., Lun, K., Luz, M., Werner, M., Brand, M. (2005). Positioning of the midbrain-hindbrain boundary organizer through global posteriorisation of the neuroectoderm mediated by Wnt8 signaling. Development 132, 1261-1272.

Winkler, S., Schwabedissen, A., Backasch, D., Bökel, C., Seidel, C., Bönisch, S., Fürthauer, M., Kuhrs, A., Cobreros, L, Brand, M. and González-Gaitán, M. (2005). Target-selected mutant screen by TILLING in Drosophila. Genome Research, 15(5):718-723.

Langenberg, T.L. and Brand, M. (2005). Lineage restriction maintains a stable organizer cell population at the zebrafish midbrain-hindbrain boundary. Development, 132(14):3209-3216.

Neural Stem Cell Activity During Adult Neurogenesis and Regeneration
A key process that is controlled by embryonic organizers like the MHB, and that is thought to be deficient in aging or diseased brains, is the proliferation of the progenitor or stem cells that give rise to the cell types in the brain. Mammalian brains differ from brains of many other vertebrates, including zebrafish, in one important aspect: Whereas in mammalian brains new neurons are born only in very restricted areas, zebrafish brains continuously produce new brain cells throughout. Our goal is therefore to understand the mechanisms that allow neural stem cells to remain active in zebrafish brains, in order to better understand how we might reactivate stem cell activity also in aging and diseased mammalian brains.
For further information, see also the Center for Regenerative Therapies (CRTD) and the Sonderforschungsbereich Cells into Tissues (SFB 655).

Genetic analysis of MHB development
A pivotal approach in our work is to manipulate the cascade of genes that regulate MHB development and function. After having intensively studied central genetic determinants of the MHB like Fgf8, Pax2a and Pou2 through mutant analysis we are now focusing on a detailed understanding of the cellular signaling and tissue distribution mechanisms of molecules involved in MHB organizer development.

Wnt8 - Upstream of the MHB
Wnt8 is signaling molecule that is needed to position the MHB organizer along the anterior-posterior axis in the early neural plate. The gene is expressed in the blastoderm margin of the gastrula embryo. We have shown that positioning of the MHB organizer is tightly linked to overall neuroectodermal posteriorization, and specifically depends on Wnt8 signaling emanating from lateral mesendodermal precursors, through defining the interface between cells expressing the Otx and Gbx transcription factors. We are currently investigating the spatial and temporal details of the molecular events that lead to early anterior-posterior patterning and MHB positioning.

MHB-dependent Polarization of the Neural Tube
In zebrafish acerebellar (ace) embryos, because of a point mutation in the Fgf8 gene, the isthmic constriction containing the MHB organizer fails to form. The absence of an MHB causes non-autonomous polarity changes along the anterior-posterior axis of the neural tube, which are reflected in altered gene expression, cell proliferation and changes in topographic axon projections.

Cellular Mechanisms of Inductive Signal Propagation
Inductive tissue interactions during embryonic development can occur over a significant spatial range. In the course of inductive processes secreted signaling molecules, such as Fgfs, need to travel from a defined source through the complex lattice of the extracellular matrix to responding target cells. It is our aim to gain a quantitative understanding on how signals spread in the embryo and are processed by responsive cells through using biochemical and biophysical approaches and advanced microscopic imaging.

Cellular Movements and Fates at the MHB
The vertebrate hindbrain is subdivided into segments, termed neuromeres, that are units of gene expression, cell differentiation and behavior. A key property of such segments is that cells show a restricted ability to mix across segment borders, termed lineage restriction. In order to address segmentation and lineage restriction in the MHB region, we have analyzed single cell behavior in the living embryo and find that midbrain and hindbrain cells arise from two distinct cell populations. Our findings suggest that segmentation as an organizing principle in early brain development can be extended to the MHB region. Ongoing work is aiming at the cellular and molecular mechanisms that underlie lineage restriction at the MHB.

Fgf-signaling During Ear Development
The vertebrate inner ear develops from initially 'simple' ectodermal placode and vesicle stages into the complex three-dimensional structure, which is necessary for the senses of hearing and equilibrium. We have studied the role of combined Fgf signaling during placode induction, maintenance and otic vesicle patterning.

DFG-Center for Regenerative Therapies Dresden (CRTD)  

SFB 655

Tracepilot - TracePilot and BioImage WIP are open-source software solutions that simplify the analyzes of phenotypes related to cell motility.

http://dasgehirn.info/ - a website about the brain made by the german "Neurowisenschaftliche Gesellschaft"

Lecture Materials for students

All current group members are listed on the Staff Page.