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 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.     

A model to develop biological probes from microflora to assure traceability of tilapia

The bacterial community of Suranaree University of Technology (SUT) tilapia was studied with the aim to develop a model for traceable biological markers. Five fish per time were collected from SUT farm and other sources. Total viable counts (TVC) of bacteria from SUT farm were quite similar in all seasons. Seventy three percent of the bacteria were Gram-negative. Total DNA extracted from the fish gills and intestines were used as template to amplify bacterial 16S rDNA V3 region using GC clamp primer to identify specific bacteria of fish origin by PCR-DGGE technique. The results showed 3 DNA bands on DGGE gel that were specific to only bacterial DNA of SUT tilapia when compared to the other sources. The 3 DNA bands were sequenced and identified as uncultured bacteria of different species. Primers were designed from the 3 specific sequences and used to amplify DNA samples from four sources and some pure cultured bacteria. The results indicated that, only one primer pair can amplify DNA samples from SUT farm but not other samples. This primer pair can be used to identify and trace samples from SUT farm. This method can be used as a model to develop bacterial primer specific location for other food products.