Reprogramming of Human Limbal Niche Progenitors.

Limbal niche cells (LNCs) possess embryonic stem cell (ESC) characteristics, expressing ESC markers such as Sox2, Nanog, and Oct4; stromal characteristics, expressing neurocrest markers such as CD90; and have angiogenic potential expressing angiogenesis markers such as CD34. In addition, these cells can be induced into adipocytes, chondrocytes, and osteocytes, indicating that they are valuable adult stem cells. However, how these cells may be appropriately passaged and maintained, what signaling pathways are necessary for such regeneration, and how the cells can be used for the treatment of various diseases caused by stem cell deficiency, such as limbal stem cell deficiency, remain unclear. Herein, we summarize the most recent advances in limbal niche research, with emphasis on the regeneration of adult limbal progenitors and their mechanisms, to promote cell-based therapy for various eye diseases due to stem cell deficiency or malfunction. Such a strategy may also provide a platform for stem cell therapy for other similar human diseases worldwide.