Lawrence J. Rizzolo
Yale University School of Medicine, USA
Rizzolo completed his Ph.D. at the age of 26 from Duke University and performed postdoctoral studies at Harvard Medical School and New York University School of Medicine. He is an Associate Professor of Surgery with a joint appointment in Ophthalmology and Visual Science at Yale University, where he won the Bohmfalk Prize for teaching. His research focuses on the outer blood-retinal barrier and degenerative diseases of the retina. He is a Fellow of the Association for Research in Vision and Ophthalmology. He has published more than 50 peer-reviewed papers and serves on numerous Editorial Boards and grant review panels.
Retinal pigment epithelium (RPE) and retinal progenitor cells (RPC) can be derived from human embryonic stem cells (hESC). These preparations have been studied in vitro and can to a remarkable degree. A shortcoming of using monocultures to understand the behavior of tissues for diff erentiate graft ing, or the eff ects of pharmaceuticals, is that the RPE forms the outer blood-retinal barrier and functions intimately with photoreceptors. To study the eff ects of these tissue interactions an experimental model has to satisfy two conditions: a culture medium is required that is compatible with each tissue and a scaff old must allow the tissues to interact with an in vivo-like geometry. RPE and RPC were derived from two hESC lines. Th e hESC-RPE was compared to human fetal RPE (hfRPE) that was isolated from 16-week fetuses. All cultures were adapted to the serum-free medium. Electrophysiologic studies showed RPE barrier properties, such as permeability and selectivity, were similar in hESCRPE and hfRPE. RNA sequencing demonstrated that the transcriptomes of hESC-RPE and hfRPE were quantitatively similar, but there signifi cant diff erences in the expression of adhesion junction and membrane transport genes. Th ese were confi rmed by quantitative RT-PCR, immunoblotting and immunofl uorescence. Th e RPC could be diff erentiated and maintained on sheets of electrospun fi bers of polycaprolactone. Ongoing experiments indicate that gene expression in RPE and RPC becomes more mature in co-culture. Th ese data indicated that hESC-derived RPE is highly diff erentiated, but appears less mature than RPE isolated from 16-week fetuses.