Abstract
Purpose: :
To examine the involvement of the chemokine CXCL12 (stromal derived factor; SDF) and its receptor CXCR4/fusin in the biology of the ocular surface cells.
Methods: :
Cadaveric human corneas and conjunctivas were obtained from NDRI under an IRB sanctioned protocol. Gene expression was determined by microarrays. Tissue cryosections and 12 hr (serum) cultures of freshly isolated epithelial cells were stained with Abs against SDF and CXCR4. SDF effect on epithelial proliferation was determined in clonal cultures grown in DMEM:Ham F12+ITS (D/F12) over 3T3 feeder cells. SDF effects on migration of human corneal stromal fibroblasts (HCFs) after scrape wounding in supplemented serum-free media were measured.
Results: :
Microarray studies indicate the presence of CXCR4 in corneal, limbal and conjunctival intact epithelia and at much higher levels in cultured cells. CXCR4 was identified in basal cells of limbal and conjunctival epithelium and in stromal keratocytes. SDF was present in the latter and in uncharacterized cells within the limbal and conjunctival stroma. SDF (10 ng/ml) increased epithelial cells recovery over that attained by addition of serum (5 %) plus EGF (1 ng/ml) by 2 and 3 fold in the limbal and conjunctival cases (n=2), respectively. When HCFs were scrap-wounded in the presence of SDF, SDF increased migration respect to control and showed an additive affect with the migratory stimulus of FGF-2.
Conclusions: :
SDF, most likely via its interaction with CXCR4, may play an important role in corneal and conjunctival functions associated with wound healing.
Keywords: cornea: stroma and keratocytes • conjunctiva • cornea: epithelium