Crosstalk among miR-29, α-SMA, and TGFß1/ß3 in melatonin-induced exosome (Mel-prExo) treated human limbal mesenchymal stem cells (hLMSCs): An insight into scarless healing of the cornea.

Inflammatory mediators that infiltrate the corneal stroma after corneal infections, trauma or refractive surgery can trigger the transformation of corneal keratocytes into myofibroblasts, resulting in highly irregular collagen deposition and subsequently corneal scarring. Mesenchymal stem cells (MSCs) can be used as therapeutic agents to regenerate corneal and conjunctival tissue damage, regulate inflammation, and reduce the development of limbal stem cell failure. The use of MSC-derived exosomes as a cell-free therapeutic vector is a novel therapeutic approach. This study aimed to assess the effect of exosomes obtained from melatonin (Mel)-treated human limbal mesenchymal stem cells (hLMSCs) on naïve hLMSCs and to determine their influence on the antifibrotic and pro-regenerative pathways involved in corneal scarring. hLMSCs were treated with varying concentrations of Mel, followed by isolation and characterization of the procured exosomes (Mel-prExos). These exosomes were added to the cell culture media of naïve hLMSCs to examine their antifibrotic and pro-regenerative effects. The expression of miR-155, miR-29, TGFß1, TGFß3, PPARγ, and α-SMA miRNAs and genes were compared between Mel-treated hLMSCs and Mel-prExo-treated hLMSCs by using real-time PCR. We found that at 1 µM Mel and in the presence of Mel-prExos, TGFß1 was expressed 0.001-fold, while TGFß3 was expressed 0.6-fold. miR-29 expression was increased 38-fold in the control-Exo group compared to that in the control group. Changes in TGFß1/ß3 and α-SMA expression are associated with miR-29 and miR-155. This approach could prove beneficial for ocular surface tissue engineering applications.

Comparison of exosomes secreted by synovial fluid-derived mesenchymal stem cells and adipose tissue-derived mesenchymal stem cells in culture for microRNA-127-5p expression during chondrogenesis.

This study aimed to investigate the differences between the exosomal microRNA-127-5p expression profiles of human adipose tissue-derived mesenchymal stem cells (hAT-MSCs) and human synovial fluid-derived mesenchymal stem cells (hSF-MSCs) during chondrogenesis in terms of regenerative treatment of cartilage. Synovial fluid-derived mesenchymal stem cells, adipose tissue-derived mesenchymal stem cells, and human fetal chondroblast cells (hfCCs) were directed to chondrogenic differentiation. Alcian Blue and Safranin O stainings were performed to detect chondrogenic differentiation histochemically. Exosomes derived from chondrogenic differentiated cells and their exosomes were isolated and characterized. microRNA-127-5p expressions were measured by Quantitative reverse transcription PCR (qRT-PCR). Significantly higher levels of microRNA-127-5p expression in differentiated hAT-MSCs exosomes, similar to human fetal chondroblast cells, which are the control group in the chondrogenic differentiation process, were observed. hAT-MSCs are better sources of microRNA-127-5p than hSF-MSCs for stimulating chondrogenesis or in the regenerative therapy of cartilage-related pathologies. hAT-MSCs exosomes are rich sources of microRNA-127-5p and can be an essential candidate for cartilage regeneration treatments.

Age-related changes in the immunomodulatory effects of human dental pulp derived mesenchymal stem cells on the CD4+ T cell subsets.

Mesenchymal stem cells (MSCs) are powerful immunomodulatory cells. The effects of the aging on these abilities of MSCs have not been adequately clarified. In this study, alterations in immunomodulatory abilities of MSCs caused by aging were investigated. For this, dental pulp (DP) MSCs and peripheral blood mononuclear cells (PBMCs) of elderly and young donors were co-cultured age-matched and cross. We detected that the effects of DP-MSCs on Th1 and Th2 cells and their specific cytokines IFN-γ and IL-4 are not affected by aging. However, we observed that young and elderly DP-MSCs have different effects on Th17 and Treg cells. Th17 frequencies of young and elderly PBMCs were significantly increased only by young DP-MSCs, in contrast, Treg frequencies were significantly increased by elderly DP-MSCs. IL-6, IL-17a and HGF levels of both young and elderly PBMCs showed a significant increase only by young DP-MSCs, but TGF-ß levels were significantly increased only by elderly DP-MSCs. The oral cavity is home to a rich microflora. The interactions of dental tissues with this microflora can lead them to acquire different epigenetic modifications. Aging can affect the microflora composition of the oral cavity and change this process in different directions. According to our findings, DP-MSCs are effective cells in the regulation of CD4+ T cells, and their effects on Th1 and Th2 cells were not affected by aging. However, pleiotropic molecules IL-6 and HGF expressions, which are important in dental and bone tissue regeneration, decreased significantly in elderly DP-MSCs. This situation may have indirectly made a difference in the modulation effects of young and elderly DP-MSCs on the Th17 and Treg cells.

Comparative Analyses of Immunosuppressive Characteristics of Bone-Marrow, Wharton's Jelly, and Adipose Tissue-Derived Human Mesenchymal Stem Cells.

OBJECTIVE: Mesenchymal stem cells (MSCs), which possess immunosuppressive characteristics on induced T-cells, were shown to be applicable in prevention and treatment of graft-versus-host disease. However, knowledge of effective cell sources is still limited. In this study, MSCs from different human tissues, i.e. bone marrow (BM), Wharton's jelly (WJ), and adipose tissue, were isolated, and the immune suppression of stimulated T cells was analyzed comparatively. MATERIALS AND METHODS: MSCs were co-cultured with phytohemagglutinin-induced T-cells with co-culture techniques with and without cell-to-cell contact. After co-culture for 24 and 96 h, the proliferation rate of T cells was estimated by carboxyfluorescein succinimidyl ester and apoptosis by annexin V/PI methods. Both T cells and MSCs were analyzed with respect to gene expressions by real-time polymerase chain reaction and their specific protein levels by ELISA. RESULTS: The results showed that all three MSC lines significantly suppressed T-cell proliferation; BM-MSCs were most effective. Similarly, T-cell apoptosis was induced most strongly by BM-MSCs in indirect culture. In T cells, the genes in NFkB and tumor necrosis factor pathways were silenced and the caspase pathway was induced after co-culture. These results were confirmed with the measurement of protein levels, like transforming growth factor ß1, IL-6, interferon-γ, interleukin (IL)-2, and tumor necrosis factor-α. Additionally, IL-17A was detected in high levels in WJ-MSC co-cultures. We showed that IL-17A-producing Tregs are the key mediators in the treatment of graft-versus-host disease. CONCLUSION: BM-MSCs, which have been used in clinical applications for a while, showed the greatest immunosuppressive effect compared to other MSCs. However, a promising cell source could also be WJ, which is also effective in suppression with fewer ethical concerns. We described the molecular mechanism of WJ-MSCs in allogenic transplants for the first time.