Umbilical cord mesenchymal stem cells are able to undergo differentiation into functional islet-like cells in type 2 diabetic tree shrews

Mesenchymal stem cells reverse thymus aging by reprogramming the DNA methylation of thymic epithelial cells

Background

A decrease in the number and activity of thymic epithelial cells (TECs) is an important factor in thymic degeneration. Mesenchymal stem cells (MSCs) treating thymic ageing is a promising strategy, but the DNA methylation modification mechanism in TECs remains unclear.

Methods

Aged rhesus monkeys were treated with MSCs to establish a thymic senescence model, and hematoxylin-eosin (HE) staining, immunofluorescence staining, and ELISA were performed to observe the structure and function of the thymus. TEC aging model and MSCs co-culture system were established to detect DNA methylation modification and transcriptomic changes, correlation analysis between transcription factor methylation and mRNA expression, and q-PCR, immunofluorescence staining, and Western blot were used to identified key genes.

Results

MSCs improved the structure and function of thymus in elderly macaque monkeys; reduced the expression levels of β-Gal, P16, and P21; and increased the activity of aging TECs. There were 501 genes with increased methylation in the promoter region in the treated group compared with the untreated group, among which 23 genes were involved in the negative regulation of cell growth, proliferation and apoptosis, while 591 genes had decreased methylation, among which 37 genes were associated with promoting cell growth and proliferation and inhibiting apoptosis. Furthermore, 66 genes showed a negative correlation between promoter methylation levels and gene transcription; specifically, PDE5A, DUOX2, LAMP1 and SVIL were downregulated with increased methylation, inhibiting growth and development, while POLR3G, PGF, CHTF18, KRT17, FOXJ1, NGF, DYRK3, LRP8, CDT1, PRELID1, F2R, KNTC1 and TRIM3 were upregulated with decreased methylation, promoting cell growth.

Conclusion

MSCs improve the structure and function of aged thymus, which involves the regulation of DNA methylation profiles and a decrease in the methylation level of the transcription factor NGF to specifically upregulate KRT17 and FOXJ1 to promote the proliferation of TECs.

Repair Effect of Umbilical Cord Mesenchymal Stem Cells Embedded in Hydrogel on Mouse Insulinoma 6 Cells Injured by Streptozotocin

Umbilical cord mesenchymal stem cells (UC-MSCs) possess the capabilities of differentiation and immune modulation, which endow them with therapeutic potential in the treatment of type 2 diabetes mellitus (T2DM). In this study, to investigate the repair mechanism of UC-MSCs in hydrogel on pancreatic β-cells in diabetes, mouse insulinoma 6 (MIN-6) cells damaged by streptozotocin (STZ) in vitro were used in co-culture with UC-MSCs in hydrogel (UC-MSCs + hydrogel). It was found that UC-MSCs + hydrogel had a significant repair effect on injured MIN-6 cells, which was better than the use of UC-MSCs alone (without hydrogel). After repair, the expression of superoxide dismutase (SOD) and catalase (CAT) as well as the total antioxidant capacity (T-AOC) of the repaired MIN-6 cells were increased, effectively reducing the oxidative stress caused by STZ. In addition, UC-MSCs + hydrogel were able to curb the inflammatory response by promoting the expression of anti-inflammatory factor IL-10 and reducing inflammatory factor IL-1β. In addition, the expression of both nuclear antigen Ki67 for cell proliferation and insulin-related genes such as Pdx1 and MafA was increased in the repaired MIN-6 cells by UC-MSCs + hydrogel, suggesting that the repair effect promotes the proliferation of the injured MIN-6 cells. Compared with the use of UC-MSCs alone, UC-MSCs + hydrogel exhibit superior antioxidant stress resistance against injured MIN-6 cells, better proliferation effects and a longer survival time of UC-MSCs because the porous structure and hydrophilic properties of the hydrogel could affect the growth of cells and slow down their metabolic activities, resulting in a better repair effect on the injured MIN-6 cells.

Differentiation of Uc-MSCs into insulin secreting islet-like clusters by trypsin through TGF-beta signaling pathway

Differentiation of human umbilical cord mesenchymal stem cells (Uc-MSCs) into islet-like clusters which are capable of synthesizing and secreting insulin can potentially serve as donors for islet transplantation in the patient deficiency in islet β cell function both in type 1 or type 2 diabetic patients. Therefore, we developed an easy and higher efficacy approach by trypsinazing the Uc-MSCs and followed culture in differentiation medium to induce of Uc-MSCs differentiation into islet-like clusters, and the potential mechanism that in the early stage of differentiation was also investigated by using RNA-sequencing and bioinformatics. Results show that induction efficacy was reached to 98% and TGF-β signaling pathway may play critical role in the early stage differentiation, it was further confirmed that the retardant effect of differentiation progress either in cell morphology or in islet specific genes expression can be observed upon blocking the activation of TGF-β signaling pathway using specific inhibitor of LY2109761 (TβRI/II kinase inhibitor). Our current study, for the first time, development a protocol for differentiation of Uc-MSCs into islet-like clusters, and revealed the importance of TGF-β signaling pathway in the early stage of differentiation of Uc-MSCs into islet-like clusters. Our study will provide alternative approach for clinical treatment of either type I or type II diabtes mellitus with dysfunctional pancreatic islets.

MicroRNA-365-3p inhibits bone marrow mesenchymal stem cell differentiation into islet-like cell clusters via targeting Pax6 and inhibiting the MEK/ERK pathway

BACKGROUND

Diabetes has severe impacts on the health of patients. The differentiation of mesenchymal stem cells (MSCs) into islet-like cell clusters (ICCs) is an effective protocol for the treatment of diabetes. microRNAs (miRs) regulate multiple cellular processes including cell differentiation. This study sought to identify the mechanism of miR-365-3p in the differentiation of bone marrow MSCs (bMSCs) into ICCs.

METHODS

Initially, the differentiation of bMSCs into ICCs was induced. Then, the miR-365-3p expression pattern in the bMSCs and ICCs was detected. Next, the miR-365-3p expression pattern was silenced in bMSCs to assess the effect on differentiation efficiency and measure the expressions of ICC marker genes during the differentiation of bMSCs into ICCs. The miR-365-3p downstream target genes were predicted and verified. Paired box protein 6 (Pax6) was downregulated in bMSCs with silenced miR-365-3p to evaluate the differentiation of bMSCs into ICCs. Furthermore, the Pax6 downstream pathway was evaluated.

RESULTS

The differentiation of bMSCs into ICCs was successfully induced. The miR-365-3p expression in bMSCs was higher than that in ICCs. miR-365-3p downregulation in bMSCs facilitated the differentiation of bMSCs into ICCs, as evidenced by elevated releases of insulin and C-peptide in ICCs and elevated expressions of ICC marker genes. Our findings denoted that miR-365-3p targeted Pax6. Inhibition of Pax6 expression annulled the promotion of miR-365-3p downregulation on the differentiation of bMSCs into ICCs. Increased phosphorylation levels of MEK and ERK were identified in ICCs after downregulation of miR-365-3p however they were decreased after downregulation of Pax6.

CONCLUSIONS

This study supported that miR-365-3p inhibited the differentiation of bMSCs into ICCs via targeting Pax6 and inhibiting the MEK/ERK pathway.

Bone marrow mesenchymal stem cells derived from juvenile macaques reversed ovarian ageing in elderly macaques

BACKGROUND

Female sex hormone secretion and reproductive ability decrease with ageing. Bone marrow mesenchymal stem cells (BMMSCs) have been postulated to play a key role in treating ovarian ageing.

METHODS

We used macaque ovarian ageing models to observe the structural and functional changes after juvenile BMMSC treatment. Moreover, RNA-seq was used to analyse the ovarian transcriptional expression profile and key pathways through which BMMSCs reverse ovarian ageing.

RESULTS

In the elderly macaque models, the ovaries were atrophied, the regulation ability of sex hormones was reduced, the ovarian structure was destroyed, and only local atretic follicles were observed, in contrast with young rhesus monkeys. Intravenous infusion of BMMSCs in elderly macaques increased ovarian volume, strengthened the regulation ability of sex hormones, reduced the degree of pulmonary fibrosis, inhibited apoptosis, increased density of blood vessels, and promoted follicular regeneration. In addition, the ovarian expression characteristics of ageing-related genes of the elderly treatment group reverted to that of the young control group, 1258 genes that were differentially expressed, among which 415 genes upregulated with age were downregulated, 843 genes downregulated with age were upregulated after BMMSC treatment, and the top 20 differentially expressed genes (DEGs) in the protein-protein interaction (PPI) network were significantly enriched in oocyte meiosis and progesterone-mediated oocyte maturation pathways.

CONCLUSION

The BMMSCs derived from juvenile macaques can reverse ovarian ageing in elderly macaques.

Human umbilical cord mesenchymal stem cells in type 2 diabetes mellitus: the emerging therapeutic approach

The umbilical cord has been proved to be an easy-access, reliable, and useful source of mesenchymal stem cells (MSC) for clinical applications due to its primitive, immunomodulatory, non-immunogenic, secretory and paracrine, migratory, proliferative, and multipotent properties. This set of characteristics has recently attracted great research interest in the fields of nanotechnology and regenerative medicine and cellular therapy. Accumulating evidence supports a pronounced therapeutic potential of MSC in many different pathologies, from hematology to immunology, wound-healing, tissue regeneration, and oncology. Diabetes mellitus, branded the epidemic of the century, is considered a chronic metabolic disorder, representing a major burden for health system sustainability and an important public health challenge to modern societies. The available treatments for type 2 diabetes mellitus (T2DM) still rely mainly on combinations of oral antidiabetic agents with lifestyle and nutritional adjustments. Despite the continuous development of novel and better hypoglycemic drugs, their efficacy is limited in the installment and progression of silent T2DM complications. T2DM comorbidities and mortality rates still make it a serious, common, costly, and long-term manageable disease. Recently, experimental models, preclinical observations, and clinical studies have provided some insights and preliminary promising results using umbilical cord MSCs to treat and manage diabetes. This review focuses on the latest research and applications of human-derived umbilical cord MSC in the treatment and management of T2DM, exploring and systematizing the key effects of both umbilical cord MSC and its factor-rich secretome accordingly with the major complications associated to T2DM.

Exosomes Derived from Human Umbilical Cord Mesenchymal Stem Cells Enhance Insulin Sensitivity in Insulin Resistant Human Adipocytes

Insulin resistance is an essential characteristic of type 2 diabetes mellitus (T2DM), which can be induced by glucotoxicity and adipose chronic inflammation. Mesenchymal stem cells (MSCs) and their exosomes were reported to ameliorate T2DM and its complications by their immunoregulatory and healing abilities. Exosomes derived from MSCs contain abundant molecules to mediate crosstalk between cells and mimic biological function of MSCs. But the role of exosomes derived from human umbilical cord mesenchymal stem cells (hUC-MSCs) in insulin resistance of human adipocytes is unclear. In this study, exosomes were harvested from the conditioned medium of hUC-MSCs and added to insulin-resistant adipocytes. Insulin-stimulated glucose uptake was measured by glucose oxidase/peroxidase assay. The signal pathway involved in exosome-treated adipocytes was detected by RT-PCR and Western blotting. The biological characteristics and function were compared between hUC-MSCs and human adipose-derived mesenchymal stem cells (hAMSCs). The results showed that hAMSCs had better adipogenic ability than hUC-MSCs. After induction of mature adipocytes by adipogenesis of hAMSC, the model of insulin-resistant adipocytes was successfully established by TNF-α and high glucose intervention. After exosome treatment, the insulin-stimulated glucose uptake was significantly increased. In addition, the effect of exosomes could be stabilized for at least 48 h. Furthermore, the level of leptin was significantly decreased, and the mRNA expression of sirtuin-1 and insulin receptor substrate-1 was significantly upregulated after exosome treatment. In conclusion, exosomes significantly improve insulin sensitivity in insulin-resistant human adipocytes, and the mechanism involves the regulation of adipokines.

The Multi-Therapeutic Role of MSCs in Diabetic Nephropathy

Diabetic nephropathy (DN) is one of the most common diabetes mellitus (DM) microvascular complications, which always ends with end-stage renal disease (ESRD). Up to now, as the treatment of DN in clinic is still complicated, ESRD has become the main cause of death in diabetic patients. Mesenchymal stem cells (MSCs), with multi-differentiation potential and paracrine function, have attracted considerable attention in cell therapy recently. Increasing studies concerning the mechanisms and therapeutic effect of MSCs in DN emerged. This review summarizes several mechanisms of MSCs, especially MSCs derived exosomes in DN therapy, including hyperglycemia regulation, anti-inflammatory, anti-fibrosis, pro-angiogenesis, and renal function protection. We also emphasize the limitation of MSCs application in the clinic and the enhanced therapeutic role of pre-treated MSCs in the DN therapy. This review provides balanced and impartial views for MSC therapy as a promising strategy in diabetic kidney disease amelioration.

Efficacy and mechanisms underlying the effects of allogeneic umbilical cord mesenchymal stem cell transplantation on acute radiation injury in tree shrews

Umbilical cord mesenchymal stem cells (UC-MSCs) exert strong immunomodulatory effects and can repair organs. However, their roles in radiation injury remain unclear. We show that in tree shrews with acute radiation injury, injected UC-MSCs significantly improved survival rates, reduced lung inflammation and apoptosis, prevented pulmonary fibrotic processes, recovered hematopoiesis, and increased blood counts. A protein microarray analysis showed that serum levels of the anti-inflammatory cytokines IL-10 and IL-13 and the growth factors BMP-5, BMP-7, HGF, insulin, NT-4, VEGFR3, and SCF were significantly higher, while those of the inflammatory cytokines IL-2, TIMP-2, TNF-α, IFN-γ, IL-1ra, and IL-8 and the fibrosis-related factors PDGF-BB, PDGF-AA, TGF-β1, IGFBP-2, and IGFBP-4 were significantly lower in UC-MSC-injected animals. A transcriptome analysis of PBMCs showed that the mRNA expression of C1q was upregulated, while that of HLA-DP was downregulated after UC-MSC injection. These results confirm the immunohistochemistry results. eGFP-labeled UC-MSCs were traced in vivo and found in the heart, liver, spleen, lungs, kidneys, thymus, small intestine and bone marrow. Our findings suggest that UC-MSC transplantation may be a novel therapeutic approach for treating acute radiation injury.

Differentiation of stem cells from apical papilla into neural lineage using graphene dispersion and single walled carbon nanotubes

Stem cell-based therapies are considered a promising treatment modality for many medical conditions. Several types of stem cells with variable differentiation potentials have been isolated from dental tissues, among them stem cells from apical papilla (SCAP). In parallel, new classes of biocompatible nanomaterials have also been developed, including graphene and carbon nanotube-based materials. The aim of the study was to assess whether graphene dispersion (GD) and water-soluble single walled carbon nanotubes (ws-SWCNT), may enhance SCAPs capacity to undergo neural differentiation. SCAPs cultivated in neuroinductive medium supplemented with GD and ws-SWCNT, separately and in combination, were subjected to neural marker analysis by real-time polymerase chain reaction (neurofilament medium [NF-M], neurogenin-2 [ngn-2], β III-tubulin, microtubule-associated protein 2) and immunocytochemistry (NeuN and β III-tubulin). GD, ws-SWCNT, and their combination, had neuro-stimulatory effects on SCAPs, as judged by the production of neural markers. Compared to cells grown in nanomaterial free medium, cells with GD showed higher production of B3T, cells with ws-SWCNT had higher production of ngn-2 and NF-M, while the combination of nanomaterials gave similar levels of both B3T and NF-M as the neuroinductive medium alone, but with the finest neuron-like morphology. In conclusion, GD and ws-SWCNT seem to enhance neural differentiation of SCAP. © 2018 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 106A: 2653-2661, 2018.

[Research progress on the donor cell sources of pancreatic islet transplantation for treatment of diabetes mellitus]

Objective

To summarize the research progress on the source and selection of donor cells in the field of islet replacement therapy for diabetes mellitus.

Methods

Domestic and abroad literature concerning islet replacement therapy for diabetes mellitus, as well as donor source and donor selection was reviewed and analyzed thoroughly.

Results

The shortage of donor supply is still a major obstacle for the widely clinical application of pancreatic islet transplantation (PIT). Currently, in addition to the progress on the allogeneic/autologous donor islet supply, some remarkable achievements have been also attained in the application of xenogeneic islet (from pig donor), as well as islet like cells derived from stem cells and islet cell line, potentially enlarging the source of implantable cells.

Conclusion

Adequate and suitable donor cell supply is an essential prerequisite for widely clinical application of PIT therapy for type 1 diabetes mellitus (T1DM). Further perfection of organ donation system, together with development of immune-tolerance induction, gene and bioengineering technology etc. will possibly solve the problem of donor cell shortage and provide a basis for clinical application of cellular replacement therapy for T1DM.