Method: We examined the RNA expression profiles in both mouse incisor CL tissue and sphere cells from our newly established OESC culture system. High expression of Sca-1, CD49f, and CD44 were found in the spheres compare to the CL tissue. Fluorescence-activated cell sorting (FACS) analyses of mouse incisor CL and OESC sphere cells with Sca-1, CD49f, and CD44 were also performed. Sphere forming assays with Sca-1, CD49f, and CD44 FACS sorted cells were used for evaluate the self-renewal and differentiation ability of each marker. Immunofluorescent studies were also performed to examine the location of these markers.
Result: FACS analyses of mouse incisor CL and OESC sphere cells based on CD44+ or Sca1+ did not enrich the cells with high sphere-forming activities. In contrast, CD49f+ cells were able to form spheres at a significantly high ratio than CD49f- cells. We also demonstrated that CD49fBright subpopulation further enriched the sphere forming cells among the CD49f+ population. CD49f+ cells were able to self-renewal and differentiate into cytokeratin 14, amelogenin expressed, and mineral material producing cells.
Conclusion: The development of an in vitro sphere culture and identifying CD49fBright as a stem cell marker for OESC will shed light on understanding the signaling networks to regulate the stem cell maintenance, cell fate, and differentiation.
Keywords: Cell culture, Teeth and stem cells
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