Endogenous bone marrow derived cells express retinal pigment epithelium cell markers and migrate to focal areas of RPE damage.
OBJECTIVE
The aim of the present study was to investigate whether bone marrow-derived cells (BMCs) can be induced to express retinal pigment epithelial (RPE) cell markers in vitro and can home to the site of RPE damage after mobilization and express markers of RPE lineage in vivo.


METHODS
Adult RPE cells were cocultured with green fluorescence protein (GFP)-labeled stem cell antigen-1 positive (Sca-1(+)) BMCs for 1, 2, and 3 weeks. Cell morphology and expression of RPE-specific markers and markers for other retinal cell types were studied. Using an animal model of sodium iodate (NaIO(3))-induced RPE degeneration, BMCs were mobilized into the peripheral circulation by granulocyte-colony stimulating factor, flt3 ligand, or both. Immunocytochemistry was used to identify and characterize BMCs in the subretinal space in C57BL/6 wild-type (wt) mice and GFP chimeric mice.


RESULTS
In vitro, BMCs changed from round to flattened, polygonal cells and expressed cytokeratin, RPE65, and microphthalmia transcription factor (MITF) when cocultured in direct cell-cell contact with RPE. In vivo, BMCs were identified in the subretinal space as Sca-1(+) or c-kit(+) cells. They were also double labeled for GFP and RPE65 or MITF. These cells formed a monolayer on the Bruch membrane in focal areas of RPE damage.


CONCLUSIONS
Thus, it appears that BMCs, when mobilized into the peripheral circulation, can home to focal areas of RPE damage and express cell markers of RPE lineage. The use of endogenous BMCs to replace damaged retinal tissue opens new possibilities for cell replacement therapy in ophthalmology.
Li
Yang
Y
Department of Ophthalmology and Visual Sciences, University of Louisville, Louisville, Kentucky, USA.
Atmaca-Sonmez
Pelin
P
Schanie
Carrie L
CL
Ildstad
Suzanne T
ST
Kaplan
Henry J
HJ
Enzmann
Volker
V
D000818:Animals; D015415:Biomarkers / Q000378:metabolism*; D001854:Bone Marrow Cells / Q000166:cytology / Q000502:physiology*; D002352:Carrier Proteins / Q000378:metabolism; D002465:Cell Movement / Q000502:physiology*; D018920:Coculture Techniques; D005136:Eye Proteins / Q000378:metabolism; D005434:Flow Cytometry; D016179:Granulocyte Colony-Stimulating Factor; D049452:Green Fluorescent Proteins / Q000378:metabolism; D007150:Immunohistochemistry; D008297:Male; D008565:Membrane Proteins; D051379:Mice; D008810:Mice, Inbred C57BL; D010504:Periodic Acid; D010857:Pigment Epithelium of Eye / Q000166:cytology / Q000502:physiology*; D012162:Retinal Degeneration / Q000139:chemically induced / Q000503:physiopathology*; D019745:cis-trans-Isomerases; D000099178:Retinoid Isomerohydrolase
D015415:Biomarkers; D002352:Carrier Proteins; D005136:Eye Proteins; D016179:Granulocyte Colony-Stimulating Factor; D049452:Green Fluorescent Proteins; D008565:Membrane Proteins; D010504:Periodic Acid; D019745:cis-trans-Isomerases; D000099178:Retinoid Isomerohydrolase; C084881:flt3 ligand protein; C009288:metaperiodate