Embryo Technology and Stem Cell Research Center, School of Biotechnology, Institute of Agricultural Technology, Suranaree University of Technology, Nakhon Ratchasima 30000, Thailand.
Laboratory of Embryo Technology, Institute of Biotechnology, Vietnam Academy of Science and Technology, Hanoi 100000, Vietnam.
Int J Mol Sci. 2022 Mar 12;23(6):3078. doi: 10.3390/ijms23063078.
Corneal epithelium, the outmost layer of the cornea, comprises corneal epithelial cells (CECs) that are continuously renewed by limbal epithelial stem cells (LESCs). Loss or dysfunction of LESCs causes limbal stem cell deficiency (LSCD) which results in corneal epithelial integrity loss and visual impairment. To regenerate the ocular surface, transplantation of stem cell-derived CECs is necessary. Human Wharton's jelly derived mesenchymal stem cells (WJ-MSCs) are a good candidate for cellular therapies in allogeneic transplantation. This study aimed to test the effects of treatments on three signaling pathways involved in CEC differentiation as well as examine the optimal protocol for inducing corneal epithelial differentiation of human WJ-MSCs. All-trans retinoic acid (RA, 5 or 10 µM) inhibited the Wnt signaling pathway via suppressing the translocation of β-catenin from the cytoplasm into the nucleus. SB505124 downregulated the TGF-β signaling pathway via reducing phosphorylation of Smad2. BMP4 did not increase phosphorylation of Smad1/5/8 that is involved in BMP signaling. The combination of RA, SB505124, BMP4, and EGF for the first 3 days of differentiation followed by supplementing hormonal epidermal medium for an additional 6 days could generate corneal epithelial-like cells that expressed a CEC specific marker CK12. This study reveals that WJ-MSCs have the potential to transdifferentiate into CECs which would be beneficial for further applications in LSCD treatment therapy.
角膜上皮是角膜的最外层，由角膜上皮细胞（CEC）组成，这些细胞由角膜缘上皮干细胞（LESC）不断更新。LESC 的缺失或功能障碍会导致角膜缘干细胞缺乏症（LSCD），从而导致角膜上皮完整性丧失和视力损害。为了再生眼表面，需要移植干细胞衍生的 CEC。人沃顿氏胶来源间充质干细胞（WJ-MSCs）是同种异体移植细胞治疗的良好候选物。本研究旨在测试三种参与 CEC 分化的信号通路的处理效果，同时检查诱导人 WJ-MSCs 角膜上皮分化的最佳方案。全反式视黄酸（RA，5 或 10μM）通过抑制β-连环蛋白从细胞质向细胞核易位来抑制 Wnt 信号通路。SB505124 通过减少 Smad2 的磷酸化来下调 TGF-β信号通路。BMP4 不会增加涉及 BMP 信号的 Smad1/5/8 的磷酸化。RA、SB505124、BMP4 和 EGF 在前 3 天的分化中联合使用，随后再补充激素表皮培养基 6 天，可以生成表达 CEC 特异性标志物 CK12 的角膜上皮样细胞。本研究表明，WJ-MSCs 具有转分化为 CEC 的潜力，这将有助于进一步应用于 LSCD 治疗。
