Constance L. Cepko
Department of Genetics
Harvard Medical School
New Research Building, Room 360
77 Avenue Louis Pasteur
Boston, MA 02115
Tel: (617) 432-7618
Fax: (617) 432-7595
5 postdoctoral fellows, 4 graduate students
We are interested in the mechanisms that direct development and degeneration of the central nervous system (CNS) of vertebrates. We are focussing our studies on the vertebrate retina, a relatively simple and well-characterized area of the CNS. We have used genomics approaches (SAGE and microarrays) to systematically examine gene expression over time during murine retinal development. We have further investigated the cellular specificity of expression patterns by performing in situ hybridization for >2000 genes with dynamic temporal patterns, and by performing gene profiling on single retinal cells. The comprehensive analysis of gene expression in over 200 single retinal cells is allowing for a computational approach to discover the networks of genes involved in several basic developmental processes. These networks are being analyzed for their roles in cell cycle control and the production of various types of retinal neurons. We are particularly interested in the diversification of the different types of interneurons as these cells form critical elements in retinal circuitry. To aid in these studies, we also carry out lineage studies wherein we mark individual progenitor cells in vivo, and analyze the types of neurons produced. Of interest is whether progenitor cells produce cells that are connected in various types of retinal circuits.
Many of our studies are facilitated by the electroporation of multiple plasmids in vivo. We have developed an electroporation method and a series of plasmids that promote the regulated expression of short hairpin RNAs, cDNA, or multiple genes and shRNA species. This method allows for relatively rapid assessment of gene function, including genetic epistasis. We are also investigating the regulatory sequences that control selected genes using electroporation of reporter plasmids. These data are then analyzed with respect to the function of suspected trans-acting factors, which can be identified through computational approaches, as well as inspection of the gene catalogues created by the single cell microarray data.
We are also interested in the mechanisms that lead to the death of photoreceptors in the many inherited forms of human blindness. Through examination of gene expression changes that accompany photoreceptor death in murine models of the human diseases, retinitis pigmentosa, we have discovered that the metabolism of cone photoreceptors appears to be stressed to the point that the cells undergo autophagy. We have found that we can slow down the death of these cells through administration of insulin, whereas the death is accelerated if animals are depleted for insulin. In addition, we have found that delivery of the histone deacetylase 4 gene can slow down the autonomous death of mutant rod photoreceptors via stabilization of the hypoxia inducible factor 1 alpha. We are now investigating whether gene therapy approaches that follow from these findings might extend vision in animal models, with the goal of developing a therapy for humans.
- Rompani, S.B., Cepko, C.L. Retinal progenitor cells can produce restricted subsets of horizontal cells. Proc. Natl. Acad. Sci. USA 105(1):192-197 (2008).
- Cherry TJ, Trimarchi JM, Stadler MB, Cepko CL. Development and diversification of retinal amacrine interneurons at single cell resolution Proc Natl Acad Sci U S A. 2009 Jun 9;106(23):9495-500.
- Chen, B and Cepko, C. HDAC4 regulates neuronal survival in normal and diseased retinas. Science, 323(5911):256-259 (2009).
- Punzo C., Kornacker K., Cepko C.L. Stimulation of the insulin/mTOR pathway delays cone death in a mouse model of Retinitis Pigmentosa. Nature Neuroscience, 12(1):44-52. (2009).
For a complete listing of publications on PubMed, click here.
BBS webpage updated 5/12/2010