RESUMO
The high temperature requirement factor A1 (HTRA1) is a serine protease which modulates an array of signalling pathways driving basal biological processes. HTRA1 plays a significant role in cell proliferation, migration and fate determination, in addition to controlling protein aggregates through refolding, translocation or degradation. The mutation of HTRA1 has been implicated in a plethora of disorders and this has also led to its growing interest as drug therapy target. This review details the involvement of HTRA1 in certain signalling pathways, namely the transforming growth factor beta (TGF-ß), canonical Wingless/Integrated (WNT) and NOTCH signalling pathways during organogenesis and various disease pathogenesis such as preeclampsia, age-related macular degeneration (AMD), small vessel disease and cancer. We have also explored possible avenues of exploiting the serine proteases for therapeutic management of these disorders.
RESUMO
BACKGROUND: c-MAF, a transcription factor that belongs to the b-Zip Maf transcription factor family, was found to be critical for lens development in vertebrates. It is a well-known fact that the adult human ocular surface expresses c-MAF, however, its role in the limbus, cornea and conjunctiva remains unknown. Thus, the present study aimed to investigate c-MAF expression within the human ocular surface, and its potential role in pterygium pathogenesis. METHODS: We performed immunohistochemical staining to detect c-MAF expression in frozen adult human tissue sections, including the limbus, cornea and conjunctiva, and cultured cells from eye cadavers. We then compared c-MAF expression to the expression of a known protein, P63. Lastly, we performed RT-PCR, and immunohistochemistry for c-MAF expression in healthy adult human conjunctiva and pterygium. RESULTS: We found differential c-MAF expression between adult human limbus, cornea and conjunctiva tissues. Further, we observed that c-MAF is downregulated in the pterygium compared to healthy conjunctiva. CONCLUSION: Overall, our results suggest that c-MAF may play a context-specific role in maintaining limbal, corneal and conjunctival homeostasis, and may be critical for preventing pterygium development in humans.
RESUMO
BACKGROUND: The human umbilical cord has been studied extensively in the past two decades. It is free of ethical dilemmas, non-tumorigenic, and less immunogenic and thus provides a significant advantage over other stem cell sources. The cord lining yields both mesenchymal and epithelial stem cells. The mesenchymal cells have been appraised at length by many researchers, which led to the current review focusing on the cord lining epithelial cells (CLECs). These cells have high proliferative capacity and their superior harvest and multiplication, using the revolutionary CellOptimaTM technology, makes them better candidates in comparison to contemporary adult stem cells. Following 30 replication cycles these cells have been observed to retain their stemness, with their phenotype and karyotype intact. However, their remarkable immunosuppressant properties, protecting self as well as co-transplanted allografts from rejection, are what truly define their transplantation potential. They have been successfully applied to many chronic conditions, using animal models, including type 1 diabetes, limbal stem cell deficiency, burn injuries, and wound healing, etc. with encouraging results. CONCLUSIONS: This review first discusses some of the advantages afforded by CLECs over other stem cell lines and then delineates their potential use in various clinical applications. Clinical trials using CLECs are currently underway in the US in collaboration with CellResearch Corp. and their potential positive findings will help garner an FDA approval, likely leading to the eventual commercialization of this promising technology.
