Steven Bassnett, Ph.D.

Ophthalmology and Visual Sciences
Cell Biology and Physiology

Molecular Cell Biology Program
Developmental, Regenerative and Stem Cell Biology Program

Research Abstract:

Our studies focus on the cell and molecular basis of lens transparency. Loss of transparency (cataract) is the most common cause of blindness in the world. A particularly interesting feature of lens development is the programmed elimination of cytoplasmic organelles from cells in the light path. We are investigating the events that trigger organelle loss and aim to determine the molecular identity of the proteases and nucleases that facilitate removal of organelles. The lens grows throughout life prompting many investigators to speculate that the tissue contains a contingent of stem cells. We are using in vivo lineage tracking strategies to investigate this hypothesis and model the growth of the lens. Preliminary data suggest a link between clonal growth of lens cells and the development in later life of cortical cataracts. Fiber cells, the terminally differentiated cells that account for most of the volume of the lens, persist throughout life. Our data suggest that these cells are unusually resistant to apoptotic stimuli. We are currently analyzing the role of IAPs (inhibitor of apoptosis proteins) in lens cell longevity using a microarray-based screening protocol in conjunction with inducible gene knockout in mice.
The size and shape of the lens is affected in patients with Marfan syndrome. This condition results from mutations in fibrillin-1, an important extracellular matrix component particularly enriched in the ciliary zonule of the eye. Current studies are evaluating the contribution of fibrillins to growth control in the lens.

Selected Publications:

De Maria, A., & Bassnett, S. Birc7: A late fiber gene of the crystalline lens (2015). Investigative Ophthalmology and Visual Sciences 56:4823-34.

Sikic, H., Shi, Y., Lubura, S., & Bassnett, S. A stochastic model of lens growth (2015). Journal of Theoretical Biology 376:15-31.

Shi, Y., De Maria, A., Lubura, S., Sikic, H., & Bassnett, S. The penny pusher: a cellular model of lens growth (2014). Investigative Ophthalmology and Visual Sciences, 56:799-809.

Shi, Y., Tu, Y., Mecham, R.P., & Bassnett, S. Ocular phenotype of Fbn2-null mice (2013). Investigative Ophthalmology and Visual Sciences, 54:7163-7167.

Shi, Y., Tu, Y., De Maria, A., Mecham, R.P., & Bassnett, S. (2013). Development, composition, and structural arrangements of the ciliary zonule of the mouse. Investigative Ophthalmology and Visual Sciences, 54:2504-2515

Shi,Y., De Maria,A., Bennett, T., Shiels, A., & Bassnett, S. (2012). A role for Epha2 in cell migration and refractive organization of the ocular lens. Investigative Ophthalmology and Visual Sciences, 53:551-9.

Bassnett, S., Shi, Y., & Vrensen, G.F. (2011). Biological glass: structural determinants of eye lens transparency. Philos Trans R Soc Lond B, 366:1250-64.

De Maria, A., Shi, Y., Luo, X., Van Der Weyden, L., & Bassnett, S. Cadm1 expression and function in the mouse lens. Invest Ophthalmol Vis Sci 2011 52:2293-9.

Bassnett, S., & Shi, Y. A method for determining cell number in the undisturbed epithelium of the mouse lens. Mol Vis 2010 16:2294-300.

Shi, Y., Barton, K., De Maria, A., Petrash, J.M., & Bassnett, S. The stratified syncytium of the vertebrate lens. J Cell Sci 2009 122:1607-15.

Last Updated: 8/12/2015 2:57:19 PM

Fibrillin-rich fibers (green) link the lens of the eye to the ciliary epithelium
Back To Top

Follow us: