Project description:Genome wide DNA methylation profiling of primary cultures of normal and diabetic corneolimbal epithelial cells. The Illumina Infinium MethylationEPIC Human DNA methylation Beadchip v1.0 B4 was used to obtain DNA methylation profiles across approximately 850,000 CpGs.
Project description:Limbal stem cells including epithelial and stromal/Mesenchymal stem cells that contribute to sustained corneal homeostasis, maintain their ability to act as self-renewal progenitor cells by virtue of their limbal niche and intercellular communication. Extracellular vehicles (EVs), including exosomes (Exos), are important paracrine mediators through their cargo transfer for intercellular communication in various stem cell niches. Previously we have shown the differential cargos and regulatory roles of limbal stromal cell (LSC)-derived Exos, in limbal epithelial cells (LEC) in normal (N) and diabetic (DM) limbal niche. In the present study, to have a comprehensive knowledge of reciprocal LEC-LSC crosstalk, we investigated the proteomics and miRNA profile of exosomes derived from LEC and their regulatory roles in LSC in N and DM limbus. Our study showed wound healing and proliferation rates in primary N-LSC were significantly enhanced upon treatment by normal LEC-derived Exos (N-Exos), but not by diabetic Exos (DM-Exos). Further, N-Exos treated LSC showed downregulation of keratocyte markers, ALDH3A1 and lumican, but not keratocan, and upregulation of MSC markers, CD105, CD90, and CD73 compared to the DM-Exos treated LSC. Using next generation sequencing (NGS) and proteomics analysis, we revealed some miRNAs and proteins in the Exos that affect the cellular crosstalk and the function of the cornea. We also documented differences in DM vs. normal LEC-derived Exo’s cargos. Overall, DM-Exos have less effect on LSC proliferation, wound healing, and stem cell maintenance than N-Exos, likely by transferring their cargo proteins and/or regulatory miRNAs targeting cell cycle, ERK/MAPK, TGF-β, EMT, PI3K-Akt-mTOR signaling molecules. This suggests that the small RNA and protein cargo differences in DM vs. N LEC-derived Exos could contribute to the disease state. Our study revealed a complex contribution of Exos to health and diabetic state of corneal homeostasis and suggests the potential of EV therapeutics for diabetic cornea regenerative medicine
Project description:The corneal epithelium is maintained by limbal epithelial stem cells (LESCs) and is largely responsible for corneal optical transparency and protection by continuously renewing population of corneal epithelial cells. Diabetes mellitus (DM) affects all structures of the eye including the cornea, which can result in delayed wound healing and potential vision loss. MicroRNAs (miRNAs) are short non-coding oligonucleotides that regulate various cellular functions, including oxidative stress response, by repressing protein translation. MiR-10b-5p was previously identified to be upregulated in diabetic vs. non-diabetic limbal cells, and our purpose was to understand the role of miR-10b-5p in human limbal epithelial cells in healthy and diabetic conditions. Through integrated transcriptomic and proteomic analyses, we identified GCLM and LANCL1 as key miR-10b-5p targets, revealing its profound impact on glutathione metabolism, sulfur compound biosynthesis processes, and antioxidant defenses. Our findings suggest that overexpression of miR-10b disrupts redox balance, which potentially leads to heightened oxidative stress and increased cellular vulnerability in diabetic corneas. Understanding miR-10b function in corneal epithelial cells may pave the way for novel therapeutic strategies to mitigate oxidative stress and normalize corneal health in diabetic patients.
Project description:Epithelial and stromal/mesenchymal limbal stem cells contribute to corneal homeostasis and cell renewal. Extracellular vesicles (EVs), including exosomes (Exos), can be paracrine mediators of intercellular communication. Previously, we described cargos and regulatory roles of limbal stromal cell (LSC)-derived Exos in non-diabetic (N) and diabetic (DM) limbal epithelial cells (LEC). Presently, we quantify the miRNA and proteome profiles of human LEC-derived Exos and their regulatory roles in N- and DM-LSC. We revealed some miRNA and protein differences in DM vs. N-LEC-derived Exos' cargos including proteins involved in Exo biogenesis and packaging that may affect Exo production and ultimately cellular crosstalk and corneal function. Treatment by N-Exos, but not by DM-Exos enhanced wound healing in cultured N-LSC and increased proliferation rate in N and DM LSCs vs. corresponding untreated (control) cells. N-Exos treated LSC reduced keratocyte markers ALDH3A1 and lumican, and increased MSC markers CD73, CD90 and CD105 vs. control LSC. These being opposite to the changes quantified in wounded LSCs. Overall, N-LEC Exos have a more pronounced effect on LSC wound healing, proliferation, and stem cell marker expression than DM-LEC Exos. This suggests that regulatory miRNA and protein cargo differences in DM- vs. N-LEC-derived Exos could contribute to the disease state.
Project description:Small non-coding RNAs, in particular microRNAs (miRNAs), regulate fine-tuning of gene expression and can impact a wide range of biological processes. Using deep sequencing analysis, we investigated miRNA expression profiles in central and limbal regions of normal and diabetic human corneas. We identified differentially expressed miRNAs in limbus vs. central cornea in normal and diabetic (DM) corneas including both type I (T1DM/IDDM) and type II (T2DM/NIDDM). Some miRNAs such as miR-10b that was upregulated in limbus vs. central corneas and in diabetic vs. normal limbus also showed significant increase in T1DM vs. T2DM limbus
Project description:Limbal epithelial stem cell (LESC) deficiency represents a significant clinical problem especially in bilateral cases. Induced pluripotent stem cells (iPSC) may be a promising source of LESC, allowing standardized and continual propagation and banking. The objective of this study was to generate iPSC from human limbal epithelial cultures and differentiate them back into limbal epithelial cells using substrata mimicking the natural LESC niche. Using Yamanaka’s episomal vectors limbal-derived iPSC were reprogrammed from LESC cultured from donor corneoscleral rims and from human skin fibroblasts. A clone from limbal-derived iPSC expressed stemness markers, had a diploid karyotype, and produced teratomas in nude mice representing three germ layers. Compared to parental LESC, this clone had fewer specific gene methylation changes revealed using the Illumina Infinium Methylation 450k Beadchips than compared to skin fibroblasts. The expression of putative LESC markers was examined by quantitative RT-PCR and immunostaining in limbal-derived and fibroblast-derived iPSC cultured on denuded human amniotic membrane or denuded cornea. Limbal-derived iPSC had markedly stronger expression of PAX6, ABCG2, Np63, keratins 14, 15, 17, and N-cadherin than fibroblast-derived iPSC. On denuded corneas, limbal-derived iPSC showed the expression of differentiated corneal keratins 3 and 12. The data suggest that iPSC differentiation to a desired lineage may be facilitated by their generation from the same tissue. This may be related to preservation of parental tissue epigenetic methylation signatures in iPSC and use of biological substrata similar to the natural niche of parental cells. The data pave the way for generating transplantable LESC from limbal-derived iPSC. Bisulphite converted DNA from the 12 samples were hybridised to the Illumina Infinium 450k Human Methylation Beadchip
Project description:ABCB5 is marker for Limbal epithilal stem cells. A comparison between ABCB5+ versus ABCB5- cultured human limbal epithelial cells was carried out to evaluate the properties of the limbal stem cell ABCB5+ with a special focus on their role in inflammation and angiogenesis.
Project description:Limbal epithelial stem cell (LESC) deficiency represents a significant clinical problem especially in bilateral cases. Induced pluripotent stem cells (iPSC) may be a promising source of LESC, allowing standardized and continual propagation and banking. The objective of this study was to generate iPSC from human limbal epithelial cultures and differentiate them back into limbal epithelial cells using substrata mimicking the natural LESC niche. Using Yamanaka’s episomal vectors limbal-derived iPSC were reprogrammed from LESC cultured from donor corneoscleral rims and from human skin fibroblasts. A clone from limbal-derived iPSC expressed stemness markers, had a diploid karyotype, and produced teratomas in nude mice representing three germ layers. Compared to parental LESC, this clone had fewer specific gene methylation changes revealed using the Illumina Infinium Methylation 450k Beadchips than compared to skin fibroblasts. The expression of putative LESC markers was examined by quantitative RT-PCR and immunostaining in limbal-derived and fibroblast-derived iPSC cultured on denuded human amniotic membrane or denuded cornea. Limbal-derived iPSC had markedly stronger expression of PAX6, ABCG2, Np63, keratins 14, 15, 17, and N-cadherin than fibroblast-derived iPSC. On denuded corneas, limbal-derived iPSC showed the expression of differentiated corneal keratins 3 and 12. The data suggest that iPSC differentiation to a desired lineage may be facilitated by their generation from the same tissue. This may be related to preservation of parental tissue epigenetic methylation signatures in iPSC and use of biological substrata similar to the natural niche of parental cells. The data pave the way for generating transplantable LESC from limbal-derived iPSC.
Project description:MicroRNA and protein cargos of human limbal epithelial cell-derived exosomes and their regulatory roles in limbal stromal cells of diabetic and non-diabetic cornea
Project description:Corneal epithelial stem cells reside in the limbus that is the transitional zone between the cornea and conjunctiva, and are essential to maintain the homeostasis of corneal epithelium. However, their characterization is poorly understood. Therefore, we constructed gene expression profiles of limbal epithelial SP and non-SP cell using RNA-sequencing. As a result, limbal epithelial SP cells have immature cell phenotypes with endothelial/mesenchymal cell markers, while limbal epithelial non-SP cells have epithelial progenitor cell markers.