Volker Busskamp - Neuronal Cell Types and Circuit Engineering


Volker Busskamp

2001 – 2006   Diploma in Biotechnology, Technical University of Braunschweig, Germany

2006 - 2007   Post graduate diploma in Biology (DEA), University of Geneva, Switzerland

2007 – 2010   PhD in Neuroscience, Friedrich Miescher Institute and University of Basel, Switzerland (Botond Roska)

2010 – 2011   Postdoctoral fellow, Friedrich Miescher Institute, Basel, Switzerland (Botond Roska)

2011 – 2014   Postdoctoral fellow, Harvard Medical School, Boston, USA (George M. Church)

Since 2014      Research Group Leader and Freigeist Fellow at the Center for Regenerative Therapies Dresden (CRTD), Germany

Previous and current research

Previously our focus was to study the human and mouse retina in health and disease. In a blinding disease called Retinitis pigmentosa, we repaired non-functional cone photoreceptors using optogenetics, specifically by expressing microbial Halorhodopsins, to restore visual function in mice. We further translated this approach to post mortem human retinas (Busskamp et al. 2010), which forms the basis for on-going clinical trials. Furthermore, our interest was to study basic functions of microRNAs in photoreceptors. We discovered that some of these non-coding RNAs had a high turnover in an activity-dependent manner (Krol et al. 2010). Upon cell type-specific knockout of the microRNA processing machinery, it turned out that a sensory-specific microRNA cluster maintains the structure of the light sensitive outer segments and the genetic identity of cone photoreceptors. Overexpression of this microRNA cluster in mouse embryonic stem cell-derived retinas resulted in the formation of outer segments that were sensitive to light (Busskamp et al. 2014).

Human stem cell-derived neurons. The overexpression of two transcription factors results in rapid neurogenesis. Four days post induction, the induced neurons (green) were positive for MAP2 (magenta), a marker for differentiated neurons.

 

 

Translating these approaches from mice to humans has been hindered by the lack of functional human neuronal tissues. This has prompted us to find novel routes to generate neurons from human induced pluripotent stem (iPS) cells. To this end, we explored the potency of transcription factors to induce neurogenesis in human iPS cells. The overexpression of two transcription factors resulted in the homogeneous differentiation of a bipolar neuronal cell type within four days. By capturing the coding and non-coding transcriptome, we aimed to identify the molecular routes for this rapid neurogenesis at the systems-level. In a second step we plan to use this knowledge to rationally engineer diverse neurons (Busskamp et al. 2014). Having succeeded with the generation of sets of different neurons, the next step is to assemble them into synthetic functional human neuronal circuits in vitro.

 

Future projects and goals

1. Human neuronal circuit engineering: In order to understand how parts of the human brain function in health and disease, our major aim is to reverse engineer functional human neuronal circuits from scratch combining neuroscience with stem cell research and bioengineering. We plan to generate the basic parts, namely electrically active neurons, from adult-derived human stem cells. Next, we need to understand and control the biology to connect these cells in a reproducible way into defined functional neuronal circuits in vitro. The lab will apply an interdisciplinary approach combining molecular biology, human stem cell differentiation, 2D neuronal pattern cultures, imaging techniques, optogenetics and electrophysiology to engineer and analyze the fabricated human neuronal circuits. Disease-causing mutations will be introduced to some circuit members trying to model brain diseases in a human setting to explore novel therapeutic interventions. Furthermore, from an engineering point of view, we aim to create biological computers using living cells to compute signals as our brain does with extreme efficiency. The Volkswagen Foundation generously funds this project.

 

2. Neuronal cell fate engineering: The discovery of pluripotent stem cells has expanded the working modes in biology towards the reverse engineering of specific cell types. Unlike studying developmental phenomena in vivo, we are now theoretically able to mimic some of these processes in a dish. The use of human iPS cells facilitates studying the genesis of human cell types in an ethically approved setting. However, exploiting the full potency of stem cells is only possible with very few differentiated cell types. In particular, the generation of neurons is in its infancy: of the many neuronal types present in the brain, only a few types have been generated in vitro. So far, neuronal differentiation protocols are multifaceted and tailored to individual cell types. The molecular events that occur during reprogramming remain enigmatic. Hence, we cannot confer these protocols easily on producing different neurons of interest. Therefore, we plan to induce transcription factors as differentiation control buttons in human iPS cells in order to explore in vitro neurogenesis systematically. First, we will apply transcription factor libraries to conditional fluorescent iPS reporter lines, facilitating high-throughput isolation and analysis of induced neurons. Second, the underlying gene regulatory networks will be revealed using RNA-sequencing over the entire differentiation period to identify the biological rules of in vitro neuronal differentiation. We will combine these in-depth transcriptomic analyses with morphological, anatomical, and functional characterizations. Conceptually, our systems biology approach paves the way for targeted “forward” programming of human iPS cells to neurons. The European Research Council (ERC) generously funds this project.

Group Members

List of group members

You can find some of us on ResearchGate:

Volker Busskamp

Simon Klapper (Postdoc)

Alex Ng (guest PhD student)

Evelyn Sauter (PhD student)

Lisa Kutsche (PhD student)

 

Selected Publications


Busskamp V, Lewis NE, Guye P, Ng AHM, Shipman SL, Byrne SE, Murn J, Sanjana NE, Li S, Li Y, Stadler M, Weiss R, Church GM. “Rapid neurogenesis through transcriptional activation in human stem cells”, Molecular Systems Biology 2014 Nov 17;10(11):760

Busskamp V, Krol J, Nelidova D, Daum J, Szikra T, Tsuda B, Jüttner J, Farrow K, Gross Scherf B, Patino Alvarez CP, Genoud C, Sothilingam V, Tanimoto N, Stadler M, Seeliger M, Stoffel M, Filipowicz M, Roska. “MicroRNAs 182 and 183 are necessary to maintain adult cone photoreceptor outer segments and visual function”, Neuron 2014 Aug 6;83(3):586-600

Chuong AS, Miri ML, Busskamp V, Matthews GAC, Acker LC, Sørensen AT, Young A, Klapoetke NC, Henninger MA, Kodandaramaiah SB, Ogawa M, Ramanlal SB, Forest CR, Chow BY, Han X, Lin Y, Tye KM, Roska B, Cardin JA, Boyden ES. “Non-invasive optogenetic neural silencing”, Nature Neuroscience 2014 Aug;17(8):1123-9.

Busskamp V, Picaud S, Sahel JA, Roska B. “Optogenetic therapy for retinitis pigmentosa”, Gene Therapy 2012 Feb;19(2):169-75.

Busskamp V, Duebel J, Balya D, Fradot M, Viney TJ, Siegert S, Groner AC, Cabuy E, Forster V, Seeliger M, Biel M, Humphries P, Paques M, Mohand-Said S, Trono D, Deisseroth K, Sahel JA, Picaud S, Roska B. ”Genetic Reactivation of Cone Photoreceptors Restores Visual Responses in Retinitis pigmentosa”, Science. 23 July 2010: Vol. 329. no. 5990, pp. 413 – 417.

Krol J, Busskamp V, Markiewicz I, Stadler MB, Ribi S, Richter J, Duebel J, Bicker S, Fehling HJ, Schübeler D, Oertner TG, Schratt G, Bibel M, Roska B, Filipowicz W. “Characterizing light-regulated retinal microRNAs reveals rapid turnover as a common property of neuronal microRNAs”, Cell. 2010 May 14;141(4):618-31.

 

Full publication list. 

 

 

 

Funding


VolkswagenStiftung “Freigeist Fellowship”        


ERC starting Grant                                   

 

Links


More information about the Freigeist fellowship.

More information about the ERC starting grant.

Optogenetic vision restoration (info for Retinitis Pigmentosa patients): http://www.gensight-biologics.com

 

Jobs

Due to the high number of applications for intern, student, PhD and Postdoc positions we are unfortunately unable to answer all requests. If your application has caught our attention, we will get back to you. Generally, vacancies are advertised under: http://www.crt-dresden.de/jobs.html and http://www.dresden-ipp.de/digs_bb.html.

We are currently advertising a PhD student position via the Dresden International PhD Program. The application deadline is July 11th 2016.

 

 

 

 

Last Modified: 31/05/2016