Marius Wernig Laboratory

“Only those who attempt the absurd can achieve the impossible.”

--Albert Einstein

Research in the Wernig Lab

Our lab is generally interested in the mechanisms that determine cell fate identity. Our focus is on epigenetic reprogramming i.e. ways to induce cell fate changes by defined factors such as the reprogramming of somatic cells into pluripotent stem (or iPS) cells. More recently, we have demonstrated that mouse fibroblasts can directly be converted to functional neuronal cells that we termed induced neuronal (iN) cells (Vierbuchen et al., 2010, Nature). The iN cells were generated through expression of the three transcription factors Ascl1, Myt1l, and Brn2. This surprising discovery opened the door to a new area of investigation. We are currently working to apply our finding to human cells, explore the molecular mechanism of the action of the three transcription factors, and determine the neuronal subtype of resulting iN cells. A long term goal is to use this method to evaluate whether iN cells can be used to model neurological diseases. In addition, the emerging iPS cell technology provides new fascinating translational applications such as patient-specific stem cell therapy or disease phenocopy through differentiation into the neural lineage. Our lab has developed new methods to generate iPS cells from human fibroblasts with defined mutations and explores various technologies to improve gene targeting in human iPS cells with a long term goal to correct disease-causing mutations. This work is made possible through a very generous CIRM grant. Another interest of the laboratory is to study self-renewal and differentiation in neural stem/progenitor cells and apply these findings to the tumor precursor cells of glioblastoma. This will shed some light into glioma generation and potentially lead to alternative treatment strategies of this devastating brain disease.

Associate Professor of Pathology and, by courtesy, of Chemical and Systems Biology

Publications

  • Early reprogramming regulators identified by prospective isolation and mass cytometry NATURE Lujan, E., Zunder, E. R., Ng, Y. H., Goronzy, I. N., Nolan, G. P., Wernig, M. 2015; 521 (7552): 352-?

    Abstract

    In the context of most induced pluripotent stem (iPS) cell reprogramming methods, heterogeneous populations of non-productive and staggered productive intermediates arise at different reprogramming time points. Despite recent reports claiming substantially increased reprogramming efficiencies using genetically modified donor cells, prospectively isolating distinct reprogramming intermediates remains an important goal to decipher reprogramming mechanisms. Previous attempts to identify surface markers of intermediate cell populations were based on the assumption that, during reprogramming, cells progressively lose donor cell identity and gradually acquire iPS cell properties. Here we report that iPS cell and epithelial markers, such as SSEA1 and EpCAM, respectively, are not predictive of reprogramming during early phases. Instead, in a systematic functional surface marker screen, we find that early reprogramming-prone cells express a unique set of surface markers, including CD73, CD49d and CD200, that are absent in both fibroblasts and iPS cells. Single-cell mass cytometry and prospective isolation show that these distinct intermediates are transient and bridge the gap between donor cell silencing and pluripotency marker acquisition during the early, presumably stochastic, reprogramming phase. Expression profiling reveals early upregulation of the transcriptional regulators Nr0b1 and Etv5 in this reprogramming state, preceding activation of key pluripotency regulators such as Rex1 (also known as Zfp42), Dppa2, Nanog and Sox2. Both factors are required for the generation of the early intermediate state and fully reprogrammed iPS cells, and thus represent some of the earliest known regulators of iPS cell induction. Our study deconvolutes the first steps in a hierarchical series of events that lead to pluripotency acquisition.

    View details for DOI 10.1038/nature14274

    View details for Web of Science ID 000354816500056

    View details for PubMedID 25830878

  • Human COL7A1-corrected induced pluripotent stem cells for the treatment of recessive dystrophic epidermolysis bullosa SCIENCE TRANSLATIONAL MEDICINE Sebastiano, V., Zhen, H. H., Derafshi, B. H., Bashkirova, E., Melo, S. P., Wang, P., Leung, T. L., Siprashvili, Z., Tichy, A., Li, J., Ameen, M., Hawkins, J., Lee, S., Li, L., Schwertschkow, A., Bauer, G., Lisowski, L., Kay, M. A., Kim, S. K., Lane, A. T., Wernig, M., Oro, A. E. 2014; 6 (264)
  • Hierarchical Mechanisms for Direct Reprogramming of Fibroblasts to Neurons CELL Wapinski, O. L., Vierbuchen, T., Qu, K., Lee, Q. Y., Chanda, S., Fuentes, D. R., Giresi, P. G., Ng, Y. H., Marro, S., Neff, N. F., Drechsel, D., Martynoga, B., Castro, D. S., Webb, A. E., Suedhof, T. C., Brunet, A., Guillemot, F., Chang, H. Y., Wernig, M. 2013; 155 (3): 621-635

    Abstract

    Direct lineage reprogramming is a promising approach for human disease modeling and regenerative medicine, with poorly understood mechanisms. Here, we reveal a hierarchical mechanism in the direct conversion of fibroblasts into induced neuronal (iN) cells mediated by the transcription factors Ascl1, Brn2, and Myt1l. Ascl1 acts as an "on-target" pioneer factor by immediately occupying most cognate genomic sites in fibroblasts. In contrast, Brn2 and Myt1l do not access fibroblast chromatin productively on their own; instead, Ascl1 recruits Brn2 to Ascl1 sites genome wide. A unique trivalent chromatin signature in the host cells predicts the permissiveness for Ascl1 pioneering activity among different cell types. Finally, we identified Zfp238 as a key Ascl1 target gene that can partially substitute for Ascl1 during iN cell reprogramming. Thus, a precise match between pioneer factors and the chromatin context at key target genes is determinative for transdifferentiation to neurons and likely other cell types.

    View details for DOI 10.1016/j.cell.2013.09.028

    View details for Web of Science ID 000326571800016

    View details for PubMedID 24243019

    View details for PubMedCentralID PMC3871197

  • Generation of oligodendroglial cells by direct lineage conversion. Nature biotechnology Yang, N., Zuchero, J. B., Ahlenius, H., Marro, S., Ng, Y. H., Vierbuchen, T., Hawkins, J. S., Geissler, R., Barres, B. A., Wernig, M. 2013; 31 (5): 434-439

    View details for DOI 10.1038/nbt.2564

    View details for PubMedID 23584610

  • Direct conversion of fibroblasts to functional neurons by defined factors NATURE Vierbuchen, T., Ostermeier, A., Pang, Z. P., Kokubu, Y., Suedhof, T. C., Wernig, M. 2010; 463 (7284): 1035-U50

    Abstract

    Cellular differentiation and lineage commitment are considered to be robust and irreversible processes during development. Recent work has shown that mouse and human fibroblasts can be reprogrammed to a pluripotent state with a combination of four transcription factors. This raised the question of whether transcription factors could directly induce other defined somatic cell fates, and not only an undifferentiated state. We hypothesized that combinatorial expression of neural-lineage-specific transcription factors could directly convert fibroblasts into neurons. Starting from a pool of nineteen candidate genes, we identified a combination of only three factors, Ascl1, Brn2 (also called Pou3f2) and Myt1l, that suffice to rapidly and efficiently convert mouse embryonic and postnatal fibroblasts into functional neurons in vitro. These induced neuronal (iN) cells express multiple neuron-specific proteins, generate action potentials and form functional synapses. Generation of iN cells from non-neural lineages could have important implications for studies of neural development, neurological disease modelling and regenerative medicine.

    View details for DOI 10.1038/nature08797

    View details for Web of Science ID 000275108400027

    View details for PubMedID 20107439