Retinal pigment epithelium damage enhances expression of chemoattractants and migration of bone marrow-derived stem cells.
OBJECTIVE
To characterize chemoattractants expressed by the retinal pigment epithelium (RPE) after sodium iodate (NaIO3)-induced damage and to investigate whether ocular-committed stem cells preexist in the bone marrow (BM) and migrate in response to the chemoattractive signals expressed by the damaged RPE.


METHODS
C57/BL6 mice were treated with a single intravenous injection of NaIO3 (50 mg/kg) to create RPE damage. At different time points real-time RT-PCR, ELISA, and immunohistochemistry were used to identify chemoattractants secreted in the subretinal space. Conditioned medium from NaIO3-treated mouse RPE was used in an in vitro assay to assess chemotaxis of stem cell antigen-1 positive (Sca-1+) BM mononuclear cells (MNCs). The expression of early ocular markers (MITF, Pax-6, Six-3, Otx) in migrated cells and in MNCs isolated from granulocyte colony-stimulating factor (G-CSF) and Flt3 ligand (FL)-mobilized and nonmobilized peripheral blood (PB) was analyzed by real-time RT-PCR.


RESULTS
mRNA for stromal cell-derived factor-1 (SDF-1), C3, hepatocyte growth factor (HGF), and leukemia inhibitory factor (LIF) was significantly increased, and higher SDF-1 and C3 protein secretion from the RPE was found after NaIO3 treatment. A higher number of BMMNCs expressing early ocular markers migrated to conditioned medium from damaged retina. There was also increased expression of early ocular markers in PBMNCs after mobilization.


CONCLUSIONS
Damaged RPE secretes cytokines that have been shown to serve as chemoattractants for BM-derived stem cells (BMSCs). Retina-committed stem cells appear to reside in the BM and can be mobilized into the PB by G-CSF and FL. These stem cells may have the potential to serve as an endogenous source for tissue regeneration after RPE damage.
Li
Yang
Y
Department of Ophthalmology and Visual Sciences, the.
Reca
Ryan G
RG
Atmaca-Sonmez
Pelin
P
Ratajczak
Mariusz Z
MZ
Ildstad
Suzanne T
ST
Kaplan
Henry J
HJ
Enzmann
Volker
V
D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D002630:Chemotactic Factors / Q000235:genetics / Q000378:metabolism*; D002634:Chemotaxis, Leukocyte / Q000502:physiology*; D004797:Enzyme-Linked Immunosorbent Assay; D005136:Eye Proteins / Q000235:genetics / Q000378:metabolism; D006412:Hematopoietic Stem Cells / Q000502:physiology*; D018398:Homeodomain Proteins / Q000235:genetics / Q000378:metabolism; D007150:Immunohistochemistry; D007275:Injections, Intravenous; D007452:Iodates / Q000633:toxicity*; D007963:Leukocytes, Mononuclear / Q000378:metabolism / Q000502:physiology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D018345:Mice, Knockout; D051739:Microphthalmia-Associated Transcription Factor / Q000235:genetics / Q000378:metabolism; D009419:Nerve Tissue Proteins / Q000235:genetics / Q000378:metabolism; D051857:Otx Transcription Factors / Q000235:genetics / Q000378:metabolism; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors / Q000235:genetics / Q000378:metabolism; D010857:Pigment Epithelium of Eye / Q000187:drug effects* / Q000378:metabolism; D012097:Repressor Proteins / Q000235:genetics / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D000097607:Homeobox Protein SIX3
D015415:Biomarkers; D002630:Chemotactic Factors; D005136:Eye Proteins; D018398:Homeodomain Proteins; D007452:Iodates; D051739:Microphthalmia-Associated Transcription Factor; D009419:Nerve Tissue Proteins; D051857:Otx Transcription Factors; D000071841:PAX6 Transcription Factor; D051761:Paired Box Transcription Factors; D012097:Repressor Proteins; D000097607:Homeobox Protein SIX3; C497235:Mitf protein, mouse; C000605732:Pax6 protein, mouse; C032285:sodium iodate