Signaling Pathways Impact on Induction of Corneal Epithelial-like Cells Derived from Human Wharton's Jelly Mesenchymal Stem Cells.

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 ß-catenin from the cytoplasm into the nucleus. SB505124 downregulated the TGF-ß 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.

Optimization of in vitro embryo production and zygote vitrification for the indigenous Vietnamese Ban pig: The effects of different in vitro oocyte maturation systems.

The Vietnamese Ban pig is a precious genetic resource that needs to be preserved. In vitro embryo production from in vitro matured (IVM) oocytes is an important tool for the utilization of cryopreserved porcine sperm. The aim of this study was to compare two media for the IVM of Ban pig oocytes. Immature oocytes were subjected to IVM either in a non-defined (TCM-199 + pig follicular fluid) or in a defined base medium (POM + epidermal growth factor). At the end of IVM, the oocytes were in vitro fertilized (IVF) with frozen Ban sperm. Ten hours after IVF, the oocytes were either subjected to orcein staining to check fertilization and maturation status or cultured in vitro for 7 days. There was no difference between the two IVM media in terms of percentages of oocyte maturation and blastocyst production. However, the percentage of male pronuclear formation after IVF and the total cell numbers in blastocysts were higher with the defined system. Zygotes obtained by the two IVM systems survived vitrification at similar rates. In conclusion, the two IVM systems were both effective for the production of Ban pig embryos; however, better embryo quality was achieved with the defined one.