My project focuses on examining the functional integration
of progenitor cells into developing and degenerate retinae.
A human neuronal cell line (RbM3), shown to possess properties
of retinal cell precursors, has been isolated in the Applebury
Lab. The line was derived from a retinoblastoma tumor of the
childhood eye; however, it does not contain mutations of the
RB1 gene, responsible for tumor formation. These cells have
been shown to be self renewing and express markers for neural
progenitors (nestin, _TubIII, neuN, etc.). Addition of bFGF
and retinoic acid to RbM3 cells in culture induces the expression
of Pax6, a gene necessary for retinal development. Culture
in the absence of sera induces morphological and physiological
differentiation into cells that express Brn3b, Islet1, calretinin,
and S opsin, markers for ganglion, horizontal, amacrine and
cone retinal cells. Xenotransplantation of the retinal progenitor
cells into P2-P3 rat eyes shows that the cells migrate and
integrate into all layers of the developing retina. Presently,
the physiological function of these newly differentiated cells
remains untested.
Retinal organ cultures are a valuable system for studying
degeneration and potential cell rescue because they provide
researchers with the exquisite ability to control the extracellular
environment. Retinal tissue cultures have been used extensively
for studies of cell growth, differentiation, cytotoxicity,
gene expression, and cell death. Such explants should provide
a useful system for studying the integration of retinal progenitor
cells and would allow the simple addition of growth factors
or hormones that might support developing cells. Significance:
Retinal progenitor cells that can be expanded and induced
to differentiate are a new resource for study of retinal development
and retinal repair. These studies can provide novel insights
into the potential use of RbM3 cells for the treatment of
retinal degeneration and damage.
Publications
Anthony J.A. Molina, A.D. Birnbaum, M.A.
Kreitzer, P.J.S. Smith, E.N. Yamoah, K. Hammar, and R.P. Malchow.
Modulation of hydrogen ion fluxes from retinal neurons. (submitted
J. Physiol.)
Anthony J.A. Molina, K. Hammar, R. Sanger, P.J.S. Smith, R.P.
Malchow. (2003) Intracellular release of caged calcium in
skate horizontal cells using fine optical fibers. Biol. Bull.
205 (2): 215
Anthony J.A. Molina, Peter J.S. Smith, and R.P. Malchow (2000)
Hydrogen ion fluxes from isolated retinal horizontal cells:
modulation by glutamate. Biol. Bull. 199: 168
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