Coordinated microRNA/mRNA expression profiles reveal a putative mechanism of corneal epithelial cell transdifferentiation from skin epidermal stem cells

Expression Patterns of miR-29b and miR-148a in Colostrum of Awassi Sheep With Higher Immunoglobulin G Levels

This study aimed to investigate the compositional parameters and expression patterns of miR-29b and miR-148a in sheep colostrum containing low and high levels of Immunoglobulin G (IgG). Blood and colostrum samples were collected within the first 6 h following birth from 24 pregnant Awassi sheep. On the basis of the determined colostrum IgG levels, low (Low IgG [LIGG], 44.83 ± 4.97 mg/mL) and high (High IgG [HIGG], 80.71 ± 3.31 mg/mL) groups were formed. In addition to measuring colostrum compositional parameters, expressions of miR-29b and miR-148a were determined in plasma and colostrum. Although somatic cell score (SCS), pH and electrical conductivity (EC) were higher, fat-free dry matter (FFDM), protein, lactose and freezing point were lower in HIGG group. Compared to LIGG, miR-29b was downregulated approximately 5-fold in the HIGG, whereas miR-148a was downregulated more than 3-fold in colostrum. There were negative correlations between colostrum miR-148a and colostrum IgG, SCS and pH. Colostrum IgG was positively correlated with pH and freezing point and negatively correlated with FFDM, protein and lactose. Area under the curve (AUC) values of SCS, pH, FFDM, protein, lactose, freezing point, EC and miR-148a (colostrum) were significant. Sensitivity and specificity of pH were 100% and 66.7%, of SCS were 81.8% and 66.7% and of miR-148a (Colostrum) were 75% and 75% in HIGG and LIGG. According to the results, miR-29b might be an important molecular target for lamb development, whereas miR-148a could be a potential biomarker for colostrum quality. Moreover, the study showed that SCS and pH might be useful diagnostic parameters for IgG status because of higher sensitivity rates and AUC values.

Progress in Transdifferentiation of Autologous Alternative Cell Sources into Corneal Epithelial Cells

Corneal limbal epithelial stem cells (LESCs) play a crucial role in corneal epithelium regeneration. Severe damage to these cells can result in limbal stem cell deficiency (LSCD), characterized by repeated corneal conjunctivalization, leading to corneal turbidity and scar formation. Restoring functional LESCs and their ecological location are essential for treating LSCD. The goal of this review is to provide researchers and clinicians with key insights into LESCs biology and to conclude the current cell-based therapies advancement in LSCD treatments. Therapeutic cell resources mainly include mesenchymal stem cells (MSCs), embryonic stem cells (ESCs), induced pluripotent stem cells (iPSCs), skin keratinocyte stem cells (SKCs), and oral mucosal epithelial cells (OMECs).

Focus on seed cells: stem cells in 3D bioprinting of corneal grafts

Corneal opacity is one of the leading causes of severe vision impairment. Corneal transplantation is the dominant therapy for irreversible corneal blindness. However, there is a worldwide shortage of donor grafts and consequently an urgent demand for alternatives. Three-dimensional (3D) bioprinting is an innovative additive manufacturing technology for high-resolution distribution of bioink to construct human tissues. The technology has shown great promise in the field of bone, cartilage and skin tissue construction. 3D bioprinting allows precise structural construction and functional cell printing, which makes it possible to print personalized full-thickness or lamellar corneal layers. Seed cells play an important role in producing corneal biological functions. And stem cells are potential seed cells for corneal tissue construction. In this review, the basic anatomy and physiology of the natural human cornea and the grafts for keratoplasties are introduced. Then, the applications of 3D bioprinting techniques and bioinks for corneal tissue construction and their interaction with seed cells are reviewed, and both the application and promising future of stem cells in corneal tissue engineering is discussed. Finally, the development trends requirements and challenges of using stem cells as seed cells in corneal graft construction are summarized, and future development directions are suggested.

Tissue Engineering Meets Nanotechnology: Molecular Mechanism Modulations in Cornea Regeneration

Nowadays, tissue engineering is one of the most promising approaches for the regeneration of various tissues and organs, including the cornea. However, the inability of biomaterial scaffolds to successfully integrate into the environment of surrounding tissues is one of the main challenges that sufficiently limits the restoration of damaged corneal tissues. Thus, the modulation of molecular and cellular mechanisms is important and necessary for successful graft integration and long-term survival. The dynamics of molecular interactions affecting the site of injury will determine the corneal transplantation efficacy and the post-surgery clinical outcome. The interactions between biomaterial surfaces, cells and their microenvironment can regulate cell behavior and alter their physiology and signaling pathways. Nanotechnology is an advantageous tool for the current understanding, coordination, and directed regulation of molecular cell-transplant interactions on behalf of the healing of corneal wounds. Therefore, the use of various nanotechnological strategies will provide new solutions to the problem of corneal allograft rejection, by modulating and regulating host-graft interaction dynamics towards proper integration and long-term functionality of the transplant.

Cellular plasticity, caspases and autophagy; that which does not kill us, well, makes us different

The ability to regenerate is a fundamental requirement for tissue homeostasis. Regeneration draws on three sources of cells. First and best-studied are dedicated stem/progenitor cells. Second, existing cells may proliferate to compensate for the lost cells of the same type. Third, a different cell type may change fate to compensate for the lost cells. This review focuses on regeneration of the third type and will discuss the contributions by post-transcriptional mechanisms including the emerging evidence for cell-autonomous and non-lethal roles of cell death pathways.