Retinoic Acid Enhances the Differentiation of Adipose-Derived Stem Cells to Keratocytes In Vitro

PURPOSE: All-trans retinoic acid (RA) supplementation was investigated as a method of enhancing the differentiation of human adipose-derived stem cells (ASCs) to corneal keratocytes in vitro, in combination with a chemically defined serum-free medium. METHODS: Adipose-derived stem cells were cultured in monolayer and supplemented with 0.1, 1, or 10 μM RA for 14 days. The effects of RA on cell proliferation, migration, and extracellular matrix (ECM) accumulation were evaluated. In addition, the expression of phenotypic keratocyte markers was examined by reverse transcription polymerase chain reaction (PCR), immunocytochemistry, and Western blotting. RESULTS: Adipose-derived stem cells cultured with RA showed improved cell proliferation and ECM production. In addition, RA enhanced the expression of keratocyte-specific markers, keratocan, aldehyde dehydrogenase 3A1, lumican, and decorin, when compared to serum-free media alone. Furthermore, the presence of RA increased the amount of collagen type I while reducing the expression of fibrotic marker, α-smooth muscle actin. CONCLUSIONS: These findings indicate that RA is a useful supplement for promoting a keratocyte phenotype in ASC. TRANSLATIONAL RELEVANCE: This study is particularly important for the generation of biological corneal substitutes and next generation cell based therapies for corneal conditions.