Making surrogate β-cells from mesenchymal stromal cells: perspectives and future endeavors

Role of Mesenchymal Stem/Stromal Cells in Head and Neck Cancer-Regulatory Mechanisms of Tumorigenic and Immune Activity, Chemotherapy Resistance, and Therapeutic Benefits of Stromal Cell-Based Pharmacological Strategies

Head and neck cancer (HNC) entails a heterogenous neoplastic disease that arises from the mucosal epithelium of the upper respiratory system and the gastrointestinal tract. It is characterized by high morbidity and mortality, being the eighth most common cancer worldwide. It is believed that the mesenchymal/stem stromal cells (MSCs) present in the tumour milieu play a key role in the modulation of tumour initiation, development and patient outcomes; they also influence the resistance to cisplatin-based chemotherapy, the gold standard for advanced HNC. MSCs are multipotent, heterogeneous and mobile cells. Although no MSC-specific markers exist, they can be recognized based on several others, such as CD73, CD90 and CD105, while lacking the presence of CD45, CD34, CD14 or CD11b, CD79α, or CD19 and HLA-DR antigens; they share phenotypic similarity with stromal cells and their capacity to differentiate into other cell types. In the tumour niche, MSC populations are characterized by cell quiescence, self-renewal capacity, low reactive oxygen species production and the acquisition of epithelial-to-mesenchymal transition properties. They may play a key role in the process of acquiring drug resistance and thus in treatment failure. The present narrative review examines the links between MSCs and HNC, as well as the different mechanisms involved in the development of resistance to current chemo-radiotherapies in HNC. It also examines the possibilities of pharmacological targeting of stemness-related chemoresistance in HNSCC. It describes promising new strategies to optimize chemoradiotherapy, with the potential to personalize patient treatment approaches, and highlights future therapeutic perspectives in HNC.

Islet Like Cells Induced from Umbilical Cord Mesenchymal Stem Cells with Neonatal Bovine Pancreatic Mesenchymal Exosomes for Treatment of Diabetes Mellitus

To investigate the safety and efficacy of the islet-like cell (cell) induced from human umbilical cord mesenchymal stem cell (UCMSC) with different methods for the treatment of diabetic animal model. UCMSCs were induced to βcells with cytokines (CY) and neonatal bovine pancreatic mesenchymal cell exosomes (Ex) combined with CY (EX+CY). The insulin secretion of UCMSC and βcell was measured with ELISA when the cells were growing in different concentrations of glucose media for different times. UCMSCs (4×105) and the same number of cells prepared with two methods were transplanted to type I diabetic rat models. UCMSCs could be induced into islet βcells by CY or EX+CY in vitro. The insulin secretion of the prepared β cells growing in 25.0 mM glucose medium was over 5-fold of that in 6.0 mM glucose. The transplantation of the βcells to type I diabetic rat models could reduce the blood glucose and prolong the survival time. The β cells induced by EX+CY had much more significant effects on decreasing blood glucose and increasing survival time (p<0.01). The cells did not affect blood sugar level and had no serious side-effects in human health. UCMSC could be induced to islet βcells with either CY or EX+CY. The transplantation of the induced islet βcells could reduce blood glucose and prolong the survival time of diabetic animal models. Although the cells induced with EX+CY had more significant effects on diabetic rats, they did not affect blood glucose level and had no serious side-effects in human health.

Microvesicles facilitate the differentiation of mesenchymal stem cells into pancreatic beta-like cells via miR-181a-5p/150-5p

Transplantation of pancreatic islet cells is a promising strategy for the long-term treatment of type 1 diabetes (T1D). The stem cell-derived beta cells showed great potential as substitute sources of transplanted pancreatic islet cells. However, the current efficiency of stem cell differentiation still cannot match the requirements for clinical transplantation. Here, we report that microvesicles (MVs) from insulin-producing INS-1 cells could induce mesenchymal stem cell (MSC) differentiation into pancreatic beta-like cells. The combination of MVs with small molecules, nicotinamide and insulin-transferrin-selenium (ITS), dramatically improved the efficiency of MSC differentiation. Notably, the function of MVs in MSC differentiation requires their entry into MSCs through giant pinocytosis. The MVs-treated or MVs combined with small molecules-treated MSCs show pancreatic beta-like cell morphology and response to glucose stimulation in insulin secretion. Using high throughput small RNA-sequencing, we found that MVs induced MSC differentiation into the beta-like cells through miR-181a-5p/150-5p. Together, our findings reveal the role of MVs or the MV-enriched miR-181a-5p/150-5p as a class of biocompatible reagents to differentiate MSCs into functional beta-like cells and demonstrate that the combined usage of MVs or miR-181a-5p/150-5p with small molecules can potentially be used in making pancreatic islet cells for future clinical purposes.

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.

Stem cells therapy for diabetes: from past to future

Diabetes mellitus is a chronic disease of carbohydrate metabolism characterized by uncontrolled hyperglycemia due to the body's impaired ability to produce or respond to insulin. Oral or injectable exogenous insulin and its analogs cannot mimic endogenous insulin secreted by healthy individuals, and pancreatic and islet transplants face a severe shortage of sources and transplant complications, all of which limit the widespread use of traditional strategies in diabetes treatment. We are now in the era of stem cells and their potential in ameliorating human disease. At the same time, the rapid development of gene editing and cell-encapsulation technologies has added to the wings of stem cell therapy. However, there are still many unanswered questions before stem cell therapy can be applied clinically to patients with diabetes. In this review, we discuss the progress of strategies to obtain insulin-producing cells from different types of stem cells, the application of gene editing in stem cell therapy for diabetes, as well as summarize the current advanced cell encapsulation technologies in diabetes therapy and look forward to the future development of stem cell therapy in diabetes.

A Supportive Role of Mesenchymal Stem Cells on Insulin-Producing Langerhans Islets with a Specific Emphasis on The Secretome

Type 1 Diabetes (T1D) is a chronic autoimmune disease characterized by a gradual destruction of insulin-producing β-cells in the endocrine pancreas due to innate and specific immune responses, leading to impaired glucose homeostasis. T1D patients usually require regular insulin injections after meals to maintain normal serum glucose levels. In severe cases, pancreas or Langerhans islet transplantation can assist in reaching a sufficient β-mass to normalize glucose homeostasis. The latter procedure is limited because of low donor availability, high islet loss, and immune rejection. There is still a need to develop new technologies to improve islet survival and implantation and to keep the islets functional. Mesenchymal stem cells (MSCs) are multipotent non-hematopoietic progenitor cells with high plasticity that can support human pancreatic islet function both in vitro and in vivo and islet co-transplantation with MSCs is more effective than islet transplantation alone in attenuating diabetes progression. The beneficial effect of MSCs on islet function is due to a combined effect on angiogenesis, suppression of immune responses, and secretion of growth factors essential for islet survival and function. In this review, various aspects of MSCs related to islet function and diabetes are described.

Wharton's jelly mesenchymal stem cells: a concise review of their secretome and prospective clinical applications

Accumulating evidence indicates that most primary Wharton's jelly mesenchymal stem cells (WJ-MSCs) therapeutic potential is due to their paracrine activity, i.e., their ability to modulate their microenvironment by releasing bioactive molecules and factors collectively known as secretome. These bioactive molecules and factors can either be released directly into the surrounding microenvironment or can be embedded within the membrane-bound extracellular bioactive nano-sized (usually 30-150 nm) messenger particles or vesicles of endosomal origin with specific route of biogenesis, known as exosomes or carried by relatively larger particles (100 nm-1 μm) formed by outward blebbing of plasma membrane called microvesicles (MVs); exosomes and MVs are collectively known as extracellular vesicles (EVs). The bioactive molecules and factors found in secretome are of various types, including cytokines, chemokines, cytoskeletal proteins, integrins, growth factors, angiogenic mediators, hormones, metabolites, and regulatory nucleic acid molecules. As expected, the secretome performs different biological functions, such as immunomodulation, tissue replenishment, cellular homeostasis, besides possessing anti-inflammatory and anti-fibrotic effects. This review highlights the current advances in research on the WJ-MSCs' secretome and its prospective clinical applications.

Perinatal Stem Cell Therapy to Treat Type 1 Diabetes Mellitus: A Never-Say-Die Story of Differentiation and Immunomodulation

Human term placenta and other postpartum-derived biological tissues are promising sources of perinatal cells with unique stem cell properties. Among the massive current research on stem cells, one medical focus on easily available stem cells is to exploit them in the design of immunotherapy protocols, in particular for the treatment of chronic non-curable human diseases. Type 1 diabetes is characterized by autoimmune destruction of pancreatic beta cells and perinatal cells can be harnessed both to generate insulin-producing cells for beta cell replenishment and to regulate autoimmune mechanisms via immunomodulation capacity. In this study, the strong points of cells derived from amniotic epithelial cells and from umbilical cord matrix are outlined and their potential for supporting cell therapy development. From a basic research and expert stem cell point of view, the aim of this review is to summarize information regarding the regenerative medicine field, as well as describe the state of the art on possible cell therapy approaches for diabetes.

Regeneration of β-cells of the islet apparatus of the pancreas. Literature review

Diabetes of both type 1 and type 2 is characterized by a progressive loss of β-cell mass, which contributes to the disruption of glucose homeostasis. The optimal antidiabetic therapy would be simple replacement of lost cells, but at present, many researchers have shown that the pancreas (PZ) of adults has a limited regenerative potential. In this regard, significant efforts of researchers are directed to methods of inducing the proliferation of β-cells, stimulating the formation of β-cells from alternative endogenous sources and/or the generation of β-cells from pluripotent stem cells. Factors that regulate β-cell regeneration under physiological or pathological conditions, such as mediators, transcription factors, signaling pathways and potential pharmaceuticals, are also being intensively studied. In this review, we consider recent scientific studies carried out in the field of studying the development and regeneration of insulin-producing cells obtained from exogenous and endogenous sources and their use in the treatment of diabetes. The literature search while writing this review was carried out using the databases of the RSIC, CyberLeninka, Scopus, Web of Science, MedLine, PubMed for the period from 2005 to 2021. using the following keywords: diabetes mellitus, pancreas, regeneration, β-cells, stem cells, diabetes therapy.

Mesenchymal stem cells inhibited the apoptosis of alveolar epithelial cells caused by ARDS through CXCL12/CXCR4 axis

Mesenchymal stem cells (MSCs) have a wide range of anti-inflammatory and immunomodulatory effects and have been observed to have potential therapeutic potential in the clinical treatment of various diseases. We pretreated lung cancer cells A549 with tumor necrosis factor (TNF-α), knocked down the key chemokine receptor CXCR4 on MSCs using lentivirus, and induced acute respiratory distress syndrome (ARDS) mouse model using lipopolysaccharide (LPS) and CXCL12 expression in vivo by adeno-associated virus (AAV-rh10) infection in mice. By co-culturing the MSCs with A549 and in vivo experiments, we observed the effects of MSCs on cell biological functions after inflammatory stimulation, oxidative stress, and the amelioration of lung injury in ARDS mice. TNF-α inhibited A549 proliferation and promoted apoptosis, scorch death-related factor activity, and oxidative stress factor were increased and CXCL12 levels in the cell supernatant were decreased. The co-culture of MSCs was able to increase cell activity and decrease oxidative stress factor levels, and this effect was not present after the knockdown of CXCR4 in MSCs. In vivo transplantation of MSCs significantly attenuated lung injury in ARDS, inhibited serum pro-inflammatory factors in mice, and down-regulated expression of apoptotic and focal factors in lung tissues while blocking CXCR4 or CXCL12 lost the repairing effect of MSCs on ARDS lung tissues. After the co-culture of MSC and lung cancer cells, the expression of CXCR4 on the surface of lung cancer cells was significantly increased, and more CXCR4 and CXCL12 acted together to activate more pro-survival pathways and inhibit apoptosis induced by TNF-α.

Navigating the Genomic Landscape of Human Adipose Stem Cell-Derived β-Cells

Diabetes is a pandemic manifested through glucose dysregulation mediated by inadequate insulin secretion by beta cells. A beta cell replacement strategy would transform the treatment paradigm from pharmacologic glucose modulation to a genuine cure. Stem cells have emerged as a potential source for beta cell (β-cell) engineering. The detailed generation of functional β-cells from both embryonic and induced pluripotent stem cells has recently been described. Adult stem cells, including adipose derived, may also offer a therapeutic approach, but remain ill defined. In our study, we performed an in-depth assessment of insulin-producing beta cells generated from human adipose, irrespective of donor patient age, gender, and health status. Cellular transformation was confirmed using flow cytometry and single-cell imaging. Insulin secretion was observed with glucose stimulation and abrogated following palmitate exposure, a common free fatty acid implicated in human beta cell dysfunction. We used next-generation sequencing to explore gene expression changes before and after differentiation of patient-matched samples, which revealed more than 5,000 genes enriched. Adipose-derived beta cells displayed comparable gene expression to native β-cells. Pathway analysis demonstrated relevance to stem cell differentiation and pancreatic developmental processes, which are vital to cellular function, structural development, and regulation. We conclude that the functions associated with adipose derived beta cells are mediated through relevant changes in the transcriptome, which resemble those seen in native β-cell morphogenesis and maturation. Therefore, they may represent a viable option for the clinical translation of stem cell-based therapies in diabetes.

Level of miR-101a and miR-107 in Human Adipose Mesenchymal Stem Cells Committed to Insulin-producing Cells

Mesenchymal stem cells have the fundamental ability to differentiate into multiple cells such as osteoblasts, neural cells, and insulin-producing cells. MicroRNAs (miRNAs) are single-strand and small non-coding RNAs involved in stem cells orientation into mature cells. There is no comprehensive data about the dynamic of distinct miRNAs during the differentiation of mesenchymal cells from adipose tissue into insulin-producing cells. In this study, we first differentiated adipose-derived mesenchymal stem cells into insulin-producing cells by a three-stepwise protocol. Differentiation capacity was confirmed by the dithizone staining method and hormone (insulin and C peptide) release analysis via electrochemiluminescence technique. In the final phase, the expression of hsa-miR-101a and hsa-miR-107 and two pancreatic genes, sex-determining region Y-box (SOX) 6 and neuronal differentiation 1 (NeuroD1) were examined during the differentiation procedure on days 0, 7, 14, 21, and 28 after induction, by using real-time PCR assay. The level of C-peptide and insulin were also measured at the end of the experiment. Dithizone staining showed trans-differentiation of adipose-derived mesenchymal stem cells into pancreatic β cells evidenced with red-to-brown appearance compared to the control group, indicating the potency to insulin production. These features were at maximum levels 28 days after cell differentiation. Real-time PCR revealed the increase of NeuroD1 and reduction of SOX6 during differentiation of stem cells toward insulin-producing cells (P <0.05). Both miR-101a and miR-107 showed prominent expression at day 28 (P <0.05). Changes in the expression of miR-101a and miR-107coincided with alteration of NeuroD1 and SOX6 that could affect mesenchymal stem cells commitment toward insulin-like beta cells.

Mesenchymal Stem Cells in Preclinical Infertility Cytotherapy: A Retrospective Review

Infertility is a global reproductive disorder which is caused by a variety of complex diseases. Infertility affects the individual, family, and community through physical, psychological, social and economic consequences. The results from recent preclinical studies regarding stem cell-based therapies are promising. Stem cell-based therapies cast a new hope for infertility treatment as a replacement or regeneration strategy. The main features and application prospects of mesenchymal stem cells in the future of infertility should be understood by clinicians. Mesenchymal stem cells (MSCs) are multipotent stem cells with abundant source, active proliferation, and multidirectional differentiation potential. MSCs play a role through cell homing, secretion of active factors, and participation in immune regulation. Another advantage is that, compared with embryonic stem cells, there are fewer ethical factors involved in the application of MSCs. However, a number of questions remain to be answered prior to safe and effective clinical application. In this review, we summarized the recent status of MSCs in the application of the diseases related to or may cause to infertility and suggest a possible direction for future cytotherapy to infertility.

Regulatory Effect of Mesenchymal Stem Cells on T Cell Phenotypes in Autoimmune Diseases

Research on mesenchymal stem cells (MSCs) starts from the earliest assumption that cells derived from the bone marrow have the ability to repair tissues. Several scientists have since documented the crucial role of bone marrow-derived MSCs (BM-MSCs) in processes such as embryonic bone and cartilage formation, adult fracture and tissue repair, and immunomodulatory activities in therapeutic applications. In addition to BM-MSCs, several sources of MSCs have been reported to possess tissue repair and immunoregulatory abilities, making them potential treatment options for many diseases. Therefore, the therapeutic potential of MSCs in various diseases including autoimmune conditions has been explored. In addition to an imbalance of T cell subsets in most patients with autoimmune diseases, they also exhibit complex disease manifestations, overlapping symptoms among diseases, and difficult treatment. MSCs can regulate T cell subsets to restore their immune homeostasis toward disease resolution in autoimmune conditions. This review summarizes the role of MSCs in relieving autoimmune diseases via the regulation of T cell phenotypes.

Islet Regeneration: Endogenous and Exogenous Approaches

Both type 1 and type 2 diabetes are characterized by a progressive loss of beta cell mass that contributes to impaired glucose homeostasis. Although an optimal treatment option would be to simply replace the lost cells, it is now well established that unlike many other organs, the adult pancreas has limited regenerative potential. For this reason, significant research efforts are focusing on methods to induce beta cell proliferation (replication of existing beta cells), promote beta cell formation from alternative endogenous cell sources (neogenesis), and/or generate beta cells from pluripotent stem cells. In this article, we will review (i) endogenous mechanisms of beta cell regeneration during steady state, stress and disease; (ii) efforts to stimulate endogenous regeneration and transdifferentiation; and (iii) exogenous methods of beta cell generation and transplantation.

Effect of Pomegranate Extract in Mesenchymal Stem Cells by Modulation of microRNA-155, microRNA-21, microRNA-23b, microRNA-126a, and PI3K\AKT1\NF-[Formula: see text]B Expression

Today, mesenchymal stem cells (MSCs) are candidates for various autoimmune disease treatments due to immunomodulatory activity in these cells. Much research has recently been done to improve the immunomodulatory activity of MSCs. Genetic variation is one of these methods. microRNAs (miRNAs) are small noncoding RNAs that control most of the cell's biological activities. Recent studies have shown that miRNAs play a significant role in the regulation of MSC immunomodulatory activity. Pomegranate is a fruit that has antioxidant, anti-inflammatory, and anticancer properties and has been used for many years for therapeutic purposes. The objective of this research is to evaluate the immunoregulatory-related miRNAs level of adipose-derived MSCs (Ad-MSCs) obtained from adipose tissue in the presence or lack of pomegranate (Punica granatum) extract (PGE). Our results showed that miRNA-23 and miRNA-126 were upregulated by PGE treatment in MSCs, and in contrast, miRNA-21 and miRNA-155 were downregulated by PGE treatment in MSCs. In addition this research shows that PGE can downregulate the expression of PI3K\AKT1\NF-[Formula: see text]B in Ad-MSCs. Our bioinformatics data have shown that the target of these four miRNAs and the signaling pathways, in which these targets are involved, can play an important role in regulating the immunomodulation function of stem cells. In conclusion, PGE can inhibit the expression of PI3K\AKT1\NF-[Formula: see text]B genes involved in inflammatory pathways via miRNA-23 and miRNA-126 overexpression or miRNA-21 and miRNA-155 downregulation that plays a role in the pathways of immune modulation in Ad-MSCs. These results may provide insight into the mechanism underlying the regulation of the immunomodulatory activity of Ad-MSCs by PGE.

Therapeutic Potential of Wharton's Jelly Mesenchymal Stem Cells for Diabetes: Achievements and Challenges

Diabetes mellitus (DM) is an alarming metabolic disease in which insulin secreting β-cells are damaged to various extent. Unfortunately, although currently available treatments help to manage the disease, however, patients usually develop complications, as well as decreased life quality and increased mortality. Thus, efficient therapeutic interventions to treat diabetes are urgently warranted. During the past years, mesenchymal stem cells (MSCs) have made their mark as a potential weapon in various regenerative medicine applications. The main fascination about MSCs lies in their potential to exert reparative effects on an amazingly wide spectrum of tissue injury. This is further reinforced by their ease of isolation and large ex vivo expansion capacity, as well as demonstrated multipotency and immunomodulatory activities. Among all the sources of MSCs, those isolated from umbilical cord-Wharton's jelly (WJ-MSCs), have been proved to provide a great source of MSCs. WJ-MSCs do not impose any ethical concerns as those which exist regarding ESCs, and represent a readily available non-invasive source, and hence suggested to become the new gold standard for MSC-based therapies. In the current review, we shall overview achievements, as well as challenges/hurdles which are standing in the way to utilize WJ-MSCs as a novel efficient therapeutic modality for DM.

In vitro differentiation of conjunctiva mesenchymal stem cells into insulin producing cells on natural and synthetic electrospun scaffolds

Polymers are used in tissue engineering as a scaffold. In this study the differentiation capability of conjunctiva mesenchymal stem cells (CJMSCs) on natural and synthetic nanofibrous electrospun scaffolds into insulin producing cells (IPCs) were studied. Natural Silk fibroin and synthetic PLLA polymers were used to fabricate electrospun scaffolds. These scaffolds are characterized by SEM and CJMSCs were differentiated into IPCs on these scaffolds. The differentiation efficiency was measured by analysis the expression of specific pancreatic markers by RT-qPCR and insulin release capacity via ELISA. Microscopy analysis showed the fabrication of uniform nanofibers and the formation of the islet-like clusters at the end of differentiation period. Significant differences in expression of Pdx-1 and glucagon were observed in PLLA scaffold compared to Silk scaffold (Fold: 1.625 and 1.434, respectively; P-value ≤ 0.0001 for both). Furthermore, insulin secretion at high glucose concentration was significantly higher in cells differentiated on PLLA scaffold than those cultured on Silk scaffold (P-value: 0.012). The scaffolds can enhance the differentiation of IPCs from CJMSCs. In this way, PLLA synthetic scaffold was more efficient than Silk natural scaffold. We conclude that the nanofibrous scaffolds reported herein could be used as a potential supportive matrix for islet tissue engineering.

Long noncoding RNA ANCR inhibits the differentiation of mesenchymal stem cells toward definitive endoderm by facilitating the association of PTBP1 with ID2

The generation of definitive endoderm (DE) cells in sufficient numbers is a prerequisite for cell-replacement therapy for liver and pancreatic diseases. Previously, we reported that human adipose-derived mesenchymal stem cells (hAMSCs) can be induced to DE lineages and subsequent functional cells. Clarifying the regulatory mechanisms underlying the fate conversion from hAMSCs to DE is helpful for developing new strategies to improve the differentiation efficiency from hAMSCs to DE organs. Long noncoding RNAs (lncRNAs) have been shown to play pivotal roles in developmental processes, including cell fate determination and differentiation. In this study, we profiled the expression changes of lncRNAs and found that antidifferentiation noncoding RNA (ANCR) was downregulated during the differentiation of both hAMSCs and embryonic stem cells (ESCs) to DE cells. ANCR knockdown resulted in the elevated expression of DE markers in hAMSCs, but not in ESCs. ANCR overexpression reduced the efficiency of hAMSCs to differentiate into DE cells. Inhibitor of DNA binding 2 (ID2) was notably downregulated after ANCR knockdown. ID2 knockdown enhanced DE differentiation, whereas overexpression of ID2 impaired this process in hAMSCs. ANCR interacts with RNA-binding polypyrimidine tract-binding protein 1 (PTBP1) to facilitate its association with ID2 mRNA, leading to increased ID2 mRNA stability. Thus, the ANCR/PTBP1/ID2 network restricts the differentiation of hAMSCs toward DE. Our work highlights the inherent discrepancies between hAMSCs and ESCs. Defining hAMSC-specific signaling pathways might be important for designing optimal differentiation protocols for directing hAMSCs toward DE.

Regenerative and Transplantation Medicine: Cellular Therapy Using Adipose Tissue-Derived Mesenchymal Stromal Cells for Type 1 Diabetes Mellitus

Type 1 diabetes mellitus (T1DM) is caused by the autoimmune targeting of pancreatic β-cells, and, in the advanced stage, severe hypoinsulinemia due to islet destruction. In patients with T1DM, continuous exogenous insulin therapy cannot be avoided. However, an insufficient dose of insulin easily induces extreme hyperglycemia or diabetic ketoacidosis, and intensive insulin therapy may cause hypoglycemic symptoms including hypoglycemic shock. While these insulin therapies are efficacious in most patients, some additional therapies are warranted to support the control of blood glucose levels and reduce the risk of hypoglycemia in patients who respond poorly despite receiving appropriate treatment. There has been a recent gain in the popularity of cellular therapies using mesenchymal stromal cells (MSCs) in various clinical fields, owing to their multipotentiality, capacity for self-renewal, and regenerative and immunomodulatory potential. In particular, adipose tissue-derived MSCs (ADMSCs) have become a focus in the clinical setting due to the abundance and easy isolation of these cells. In this review, we outline the possible therapeutic benefits of ADMSC for the treatment of T1DM.

Mesenchymal Stem Cells: Miraculous Healers or Dormant Killers?

Mesenchymal Stem Cells (MSCs) are a heterogeneous population of fibroblast-like cells which maintain self-renewability and pluripotency to differentiate into mesodermal cell lineages. The use of MSCs in clinical settings began with high enthusiasm and the number of MSC-based clinical trials has been rising ever since. However; the very unique characteristics of MSCs that made them suitable to for therapeutic use, might give rise to unwanted outcomes, including tumor formation and progression. In this paper, we present a model of carcinogenesis initiated by MSCs, which chains together the tissue organization field theory, the stem cell theory, and the inflammation-cancer chain. We believe that some tissue resident stem cells could be leaked cells from bone marrow MSC pool to various injured tissue, which consequently transform and integrate in the host tissue. If the injury persists or chronic inflammation develops, as a consequence of recurring exposure to growth factors, cytokines, etc. the newly formed tissue from MSCs, which still has conserved their mesenchymal and stemness features, go through rapid population expansion, and nullify their tumor suppressor genes, and hence give rise to neoplastic cell (carcinomas, sarcomas, and carcino-sarcomas). Considering the probability of this hypothesis being true, the clinical and therapeutic use of MSCs should be with caution, and the recipients' long term follow-up seems to be insightful.

3D-Models of Insulin-Producing β-Cells: from Primary Islet Cells to Stem Cell-Derived Islets

There is a need for physiologically relevant assay platforms to provide functionally relevant models of diabetes, to accelerate the discovery of new treatment options and boost developments in drug discovery. In this review, we compare several 3D-strategies that have been used to increase the functional relevance of ex vivo human primary pancreatic islets and developments into the generation of stem cell derived pancreatic beta-cells (β-cells). Special attention will be given to recent approaches combining the use of extracellular matrix (ECM) scaffolds with pancreatic molecular memory, which can be used to improve yield and functionality of in vitro stem cell-derived pancreatic models. The ultimate goal is to develop scalable cell-based platforms for diabetes research and drug screening. This article will critically assess key aspects related to in vitro pancreatic 3D-ECM models and highlight the most promising approaches for future research.

Mesenchymal stem cells to treat type 1 diabetes

What is clear is we are in the era of the stem cell and its potential in ameliorating human disease. Our perspective is generated from an in vivo model in a large animal that offers significant advantages (complete transplantation tolerance, large size and long life span). This review is an effort to meld our preclinical observations with others for the reader and to outline potential avenues to improve the present outlook for patients with diabetes. This effort exams the history or background of stem cell research in the laboratory and the clinic, types of stem cells, pluripotency or lack thereof based on a variety of pre-clinical investigations attempting endocrine pancreas recovery using stem cell transplantation. The focus is on the use of hematopoietic and mesenchymal stem cells. This review will also examine recent clinical experience following stem cell transplantation in patients with type 1 diabetes.

Targeted deletion of Insm2 in mice result in reduced insulin secretion and glucose intolerance

Background

Neurogenin3 (Ngn3) and neurogenic differentiation 1 (NeuroD1), two crucial transcriptional factors involved in human diabetes (OMIM: 601724) and islet development, have been previously found to directly target to the E-boxes of the insulinoma-associated 2 (Insm2) gene promoter, thereby activating the expression of Insm2 in insulin-secretion cells. However, little is known about the function of Insm2 in pancreatic islets and glucose metabolisms.

Methods

Homozygous Insm2^−/− mice were generated by using the CRISPR-Cas9 method. Glucose-stimulated insulin secretion and islet morphology were analyzed by ELISA and immunostainings. Expression levels of Insm2-associated molecules were measured using quantitative RT-PCR and Western blots.

Results

Fasting blood glucose levels of Insm2^−/− mice were higher than wild-type counterparts. Insm2^−/− mice also showed reduction in glucose tolerance and insulin/C-peptide levels when compared to the wild-type mice. RT-PCR and Western blot analysis revealed that expression of Insm1 was significantly increased in Insm2^−/− mice, suggesting a compensatory response of the homolog gene Insm1. Similarly, transcriptional levels of Ngn3 and NeuroD1 were also increased in Insm2^−/− mice. Moreover, Insm2^−/− female mice showed a significantly decreased reproductive capacity.

Conclusions

Our findings suggest that Insm2 is important in glucose-stimulated insulin secretion and is involved in the development pathway of neuroendocrine tissues which are regulated by the transcription factors Ngn3, NeuroD1 and Insm1.

CD34- human placenta-derived mesenchymal stem cells protect against heat stroke mortality in rats

CD34 is a transmembrane phosphoglycoprotein used to selectively enrich bone marrow in hematopoietic stem cells for transplantation. Treating rats with CD34⁺ cells derived from human umbilical cord blood before or after heat stroke has been shown to promote survival. We investigated whether CD34^– human placenta-derived stem cells (PDMSCs) could improve survival following heat stroke in rats. Rats were subjected to heat stress (42°C for 98 min) to induce heat stroke. Intravenous administration of PDMSCs 1 day before or immediately after the onset of heat stroke improved survival by 60% and 20%, respectively. Pre-treatment with CD34⁻ PDMSCs protected against heat stroke injury more effectively than that treatment after injury. PDMSCs treatment attenuated cerebrovascular dysfunction, the inflammatory response, and lipid peroxidation. These data suggest human PDMSCs protect against heat stroke injury in rats. Moreover, these effects do not require the presence of CD34⁺ cells.

[Fibroblast growth factors and their effects in pancreas organogenesis]

Fibroblast growth factors (FGF) - growth factors that regulate many important biological processes, including proliferation and differentiation of embryonic cells during organogenesis. In this review, we will summarize current information about the involvement of FGFs in the pancreas organogenesis. Pancreas organogenesis is a complex process, which involves constant signaling from mesenchymal tissue. This orchestrates the activation of various regulator genes at specific stages, determining the specification of progenitor cells. Alterations in FGF/FGFR signaling pathway during this process lead to incorrect activation of the master genes, which leads to different pathologies during pancreas development. Understanding the full picture about role of FGF factors in pancreas development will make it possible to more accurately understand their role in other pathologies of this organ, including carcinogenesis.

Induction of Nestin Early Expression as a Hallmark for Mesenchymal Stem Cells Expression of PDX-1 as a Pre-disposing Factor for Their Conversion into Insulin Producing Cells

Diabetes constitutes a worldwide epidemic that affects all ethnic groups. Cell therapy is one of the best alternatives of treatment, by providing an effective way to regenerate insulin-producing cells lost during the course of the disease, but many issues remain to be solved. Several groups have been working in the development of a protocol capable of differentiating Mesenchymal Stem Cells (MSCs) into physiologically sound Insulin Producing Cells (IPCs). In order to obtain a simple, fast and direct method, we propose in this manuscript the induction of MSCs to express NESTIN in a short time period (2 h), proceeded by incubation in a low glucose induced medium (24 h) and lastly by incubation in a high glucose medium. Samples from cell cultures incubated in high glucose medium from 12 to 168 h were obtained to detect the expression of INSULIN-1, INSULIN -2, PDX-1 and GLUT-2 genes. Induced cells were exposed to a glucose challenge, in order to assess the production of insulin. This method allowed us to obtain cells expressing PDX-1, which resembles a progenitor insulin-producing cell.

From Human Mesenchymal Stem Cells to Insulin-Producing Cells: Comparison between Bone Marrow- and Adipose Tissue-Derived Cells

The aim of this study is to compare human bone marrow-derived mesenchymal stem cells (BM-MSCs) and adipose tissue-derived mesenchymal stem cells (AT-MSCs), for their differentiation potentials to form insulin-producing cells. BM-MSCs were obtained during elective orthotopic surgery and AT-MSCs from fatty aspirates during elective cosmetics procedures. Following their expansion, cells were characterized by phenotyping, trilineage differentiation ability, and basal gene expression of pluripotency genes and for their metabolic characteristics. Cells were differentiated according to a Trichostatin-A based protocol. The differentiated cells were evaluated by immunocytochemistry staining for insulin and c-peptide. In addition the expression of relevant pancreatic endocrine genes was determined. The release of insulin and c-peptide in response to a glucose challenge was also quantitated. There were some differences in basal gene expression and metabolic characteristics. After differentiation the proportion of the resulting insulin-producing cells (IPCs), was comparable among both cell sources. Again, there were no differences neither in the levels of gene expression nor in the amounts of insulin and c-peptide release as a function of glucose challenge. The properties, availability, and abundance of AT-MSCs render them well-suited for applications in regenerative medicine. Conclusion. BM-MSCs and AT-MSCs are comparable regarding their differential potential to form IPCs. The availability and properties of AT-MSCs render them well-suited for applications in regenerative medicine.

Adult muscle-derived stem cells engraft and differentiate into insulin-expressing cells in pancreatic islets of diabetic mice

Background

Pancreatic beta cells are unique effectors in the control of glucose homeostasis and their deficiency results in impaired insulin production leading to severe diabetic diseases. Here, we investigated the potential of a population of nonadherent muscle-derived stem cells (MDSC) from adult mouse muscle to differentiate in vitro into beta cells when transplanted as undifferentiated stem cells in vivo to compensate for beta-cell deficiency.

Results

In vitro, cultured MDSC spontaneously differentiated into insulin-expressing islet-like cell clusters as revealed using MDSC from transgenic mice expressing GFP or mCherry under the control of an insulin promoter. Differentiated clusters of beta-like cells co-expressed insulin with the transcription factors Pdx1, Nkx2.2, Nkx6.1, and MafA, and secreted significant levels of insulin in response to glucose challenges. In vivo, undifferentiated MDSC injected into streptozotocin (STZ)-treated mice engrafted within 48 h specifically to damaged pancreatic islets and were shown to differentiate and express insulin 10–12 days after injection. In addition, injection of MDSC into hyperglycemic diabetic mice reduced their blood glucose levels for 2–4 weeks.

Conclusion

These data show that MDSC are capable of differentiating into mature pancreatic beta islet-like cells, not only upon culture in vitro, but also in vivo after systemic injection in STZ-induced diabetic mouse models. Being nonteratogenic, MDSC can be used directly by systemic injection, and this potential reveals a promising alternative avenue in stem cell-based treatment of beta-cell deficiencies.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-017-0539-9) contains supplementary material, which is available to authorized users.

Clinical potentials of human pluripotent stem cells

Aging, injuries, and diseases can be considered as the result of malfunctioning or damaged cells. Regenerative medicine aims to restore tissue homeostasis by repairing or replacing cells, tissues, or damaged organs, by linking and combining different disciplines including engineering, technology, biology, and medicine. To pursue these goals, the discipline is taking advantage of pluripotent stem cells (PSCs), a peculiar type of cell possessing the ability to differentiate into every cell type of the body. Human PSCs can be isolated from the blastocysts and maintained in culture indefinitely, giving rise to the so-called embryonic stem cells (ESCs). However, since 2006, it is possible to restore in an adult cell a pluripotent ESC-like condition by forcing the expression of four transcription factors with the rejuvenating reprogramming technology invented by Yamanaka. Then the two types of PSC can be differentiated, using standardized protocols, towards the cell type necessary for the regeneration. Although the use of these derivatives for therapeutic transplantation is still in the preliminary phase of safety and efficacy studies, a lot of efforts are presently taking place to discover the biological mechanisms underlying genetic pathologies, by differentiating induced PSCs derived from patients, and new therapies by challenging PSC-derived cells in drug screening.

TGF-β engineered mesenchymal stem cells (TGF-β/MSCs) for treatment of Type 1 diabetes (T1D) mice model

OBJECTIVE

Mesenchymal stem cells (MSCs) are advantageous candidates for cell therapy of Type 1 diabetes (T1D). Considering immunomodulatory effect of MSC, in this study, we engineered MSCs with TGF-β gene to increase MSC potency for T1D therapy in mouse model.

MATERIALS AND METHODS

Two plans were designed for prevention and treatment of diabetes, respectively. In both of them, MSCs were injected i.v. and then, the diabetes features including serum insulin, blood glucose, glucose tolerance, splenocytes proliferation, and IL-4/IFN-γ production were evaluated.

RESULTS

TGF-β/MSCs treatment program resulted in the restoration of serum glucose after 3weeks, while prevention program could delay diabetes progression for two weeks. TGF-β/MSCs treatment elevated the levels of serum insulin and Th2 cytokine shift on 5th week after start of treatment. TGF-β/MSCs (and MSCs alone) could also diminish body weight and enhance mice survival comparing to untreated diabetic mice.

CONCLUSION

Engineered TGF-β/MSCs could restore some T1D features, including the regulation of adverse immune responses and could be potent tools for cell therapy of T1D comparing MSCs alone.

Therapeutic potential of dental stem cells

Stem cell biology has become an important field in regenerative medicine and tissue engineering therapy since the discovery and characterization of mesenchymal stem cells. Stem cell populations have also been isolated from human dental tissues, including dental pulp stem cells, stem cells from human exfoliated deciduous teeth, stem cells from apical papilla, dental follicle progenitor cells, and periodontal ligament stem cells. Dental stem cells are relatively easily obtainable and exhibit high plasticity and multipotential capabilities. The dental stem cells represent a gold standard for neural-crest-derived bone reconstruction in humans and can be used for the repair of body defects in low-risk autologous therapeutic strategies. The bioengineering technologies developed for tooth regeneration will make substantial contributions to understand the developmental process and will encourage future organ replacement by regenerative therapies in a wide variety of organs such as the liver, kidney, and heart. The concept of developing tooth banking and preservation of dental stem cells is promising. Further research in the area has the potential to herald a new dawn in effective treatment of notoriously difficult diseases which could prove highly beneficial to mankind in the long run.

Zinc Up-Regulates Insulin Secretion from β Cell-Like Cells Derived from Stem Cells from Human Exfoliated Deciduous Tooth (SHED)

Stem cells from human exfoliated deciduous tooth (SHED) offer several advantages over other stem cell sources. Using SHED, we examined the roles of zinc and the zinc uptake transporter ZIP8 (Zrt- and irt-like protein 8) while inducing SHED into insulin secreting β cell-like stem cells (i.e., SHED-β cells). We observed that ZIP8 expression increased as SHED differentiated into SHED-β cells, and that zinc supplementation at day 10 increased the levels of most pancreatic β cell markers-particularly Insulin and glucose transporter 2 (GLUT2). We confirmed that SHED-β cells produce insulin successfully. In addition, we note that zinc supplementation significantly increases insulin secretion with a significant elevation of ZIP8 transporters in SHED-β cells. We conclude that SHED can be converted into insulin-secreting β cell-like cells as zinc concentration in the cytosol is elevated. Insulin production by SHED-β cells can be regulated via modulation of zinc concentration in the media as ZIP8 expression in the SHED-β cells increases.

Exendin-4 enhances the differentiation of Wharton's jelly mesenchymal stem cells into insulin-producing cells through activation of various β-cell markers

Background

Diabetes mellitus is a devastating metabolic disease. Generation of insulin-producing cells (IPCs) from stem cells, especially from Wharton’s jelly mesenchymal stem cells (WJ-MSCs), has sparked much interest recently. Exendin-4 has several beneficial effects on MSCs and β cells. However, its effects on generation of IPCs from WJ-MSCs specifically have not been studied adequately. The purpose of this study was therefore to investigate how exendin-4 could affect the differentiation outcome of WJ-MSCs into IPCs, and to investigate the role played by exendin-4 in this differentiation process.

Methods

WJ-MSCs were isolated, characterized and then induced to differentiate into IPCs using two differentiation protocols: protocol A, without exendin-4; and protocol B, with exendin-4. Differentiated IPCs were assessed by the expression of various β-cell-related markers using quantitative RT-PCR, and functionally by measuring glucose-stimulated insulin secretion.

Results

The differentiation protocol B incorporating exendin-4 significantly boosted the expression levels of β-cell-related genes Pdx-1, Nkx2.2, Isl-1 and MafA. Moreover, IPCs generated by protocol B showed much better response to variable glucose concentrations as compared with those derived from protocol A, which totally lacked such response. Furthermore, exendin-4 alone induced early differentiation markers such as Pdx-1 and Nkx2.2 but not Isl-1, besides inducing late markers such as MafA. In addition, exendin-4 showed a synergistic effect with nicotinamide and β-mercaptoethanol in the induction of these markers.

Conclusions

Exendin-4 profoundly improves the differentiation outcome of WJ-MSCs into IPCs, possibly through the ability to induce the expression of β-cell markers.

Electronic supplementary material

The online version of this article (doi:10.1186/s13287-016-0374-4) contains supplementary material, which is available to authorized users.

Association of expression levels of pluripotency/stem cell markers with the differentiation outcome of Wharton's jelly mesenchymal stem cells into insulin producing cells

Recently, there has been much attention towards generation of insulin producing cells (IPCs) from stem cells, especially from Wharton's jelly mesenchymal stem cells (WJ-MSCs). However, generation of mature IPCs remains a challenge. Assessment of generation of IPCs was usually done by examining β-cell markers, however, assessment of pluripotency/stem cell markers drew less attention. Therefore, the purpose of this study was to investigate the levels of pluripotency/stem cell markers during differentiation of WJ-MSCs into IPCs and the association of these levels with differentiation outcomes. WJ-MSCs were isolated, characterized then induced to differentiate into IPCs using three different protocols namely A, B and C. Differentiated IPCs were assessed by the expression of pluripotency/stem cell markers, together with β-cell markers using qRT-PCR, and functionally by measuring glucose stimulated insulin secretion. Differentiated cells from protocol A showed lowest expression of pluripotency/stem cell markers and relatively best GSIS. However, protocol B showed concomitant expression of pluripotency/stem cell and β-cell markers with relatively less insulin secretion as compared to protocol A. Protocol C failed to generate glucose-responsive IPCs. In conclusion, sustained expression of pluripotency/stem cell markers could be associated with the incomplete differentiation of WJ-MSCs into IPCs. A novel finding for which further investigations are warranted.

Regenerative Therapy of Type 1 Diabetes Mellitus: From Pancreatic Islet Transplantation to Mesenchymal Stem Cells

Type 1 diabetes is an autoimmune disease resulting in the permanent destruction of pancreatic islets. Islet transplantation to portal vein provides an approach to compensate for loss of insulin producing cells. Clinical trials demonstrated that even partial islet graft function reduces severe hypoglycemic events in patients. However, therapeutic impact is restrained due to shortage of pancreas organ donors and instant inflammation occurring in the hepatic environment of the graft. We summarize on what is known about regenerative therapy in type 1 diabetes focusing on pancreatic islet transplantation and new avenues of cell substitution. Metabolic pathways and energy production of transplanted cells are required to be balanced and protection from inflammation in their intravascular bed is desired. Mesenchymal stem cells (MSCs) have anti-inflammatory features, and so they are interesting as a therapy for type 1 diabetes. Recently, they were reported to reduce hyperglycemia in diabetic rodents, and they were even discussed as being turned into endodermal or pancreatic progenitor cells. MSCs are recognized to meet the demand of an individual therapy not raising the concerns of embryonic or induced pluripotent stem cells for therapy.

Therapeutic efficacy of differentiated versus undifferentiated mesenchymal stem cells in experimental type I diabetes in rat

Selective MSCs differentiation protocol into pancreatic beta cells was conducted in the present study using exendin-4 and TGF-beta. Differentiated and undifferentiated MSCs were assessed in experimental type I diabetes in rats. Ninety female white albino rats were included in the study and divided equally (n=15/group) into 6 groups: healthy control, healthy control rats received acellular tissue culture medium, diabetic rats, diabetic rats received acellular tissue culture medium, diabetic rats received undifferentiated MSCs and diabetic rats received differentiated MSCs. Therapeutic efficacy of undifferentiated versus differentiated MSCs was evaluated via assessment of quantitative gene expressions of insulin1, insulin 2, Smad-2, Smad-3, PDX-1, PAX-4, neuroD. Blood glucose and insulin hormone levels were also assessed. Results showed that quantitative gene expressions of all studied genes showed significant decrease in diabetic rat groups. Use of undifferentiated and differentiated MSCs led to a significant elevation of expression levels of all genes with more superior effect with differentiated MSCs except smad-2 gene. As regards insulin hormone levels, use of either undifferentiated or differentiated MSCs led to a significant elevation of its levels with more therapeutic effect with differentiated MSCs. Blood glucose levels were significantly decreased with both undifferentiated and differentiated MSCs in comparison to diabetic groups but its levels were normalized 2 months after injection of differentiated MSCs. In conclusion, use of undifferentiated or differentiated MSCs exhibited significant therapeutic potentials in experimental type I diabetes in rats with more significant therapeutic effect with the use of differentiated MSCs.

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Differentiated MSCs exhibited significant therapeutic potentials in type I diabetes.

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TGF-beta1 and exendin-4 enhance MSCs differentiation into pancreatic beta cells.

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Pancreatic lineage is evaluated by gene expressions of insulin-1, insulin-2.

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Pancreatic differentiation is evaluated by expressions of PDX-1, PAX-4 and NeuroD.

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Differentiated MSCs have more therapeutic potentials than undifferentiated MSCs.

In Vivo Differentiation of Therapeutic Insulin-Producing Cells from Bone Marrow Cells via Extracellular Vesicle-Mimetic Nanovesicles

The current diabetes mellitus pandemic constitutes an important global health problem. Reductions in the mass and function of β-cells contribute to most of the pathophysiology underlying diabetes. Thus, physiological control of blood glucose levels can be adequately restored by replacing functioning β-cell mass. Sources of functional islets for transplantation are limited, resulting in great interest in the development of alternate sources, and recent progress regarding cell fate change via utilization of extracellular vesicles, also known as exosomes and microvesicles, is notable. Thus, this study investigated the therapeutic capacity of extracellular vesicle-mimetic nanovesicles (NVs) derived from a murine pancreatic β-cell line. To differentiate insulin-producing cells effectively, a three-dimensional in vivo microenvironment was constructed in which extracellular vesicle-mimetic NVs were applied to subcutaneous Matrigel platforms containing bone marrow (BM) cells in diabetic immunocompromised mice. Long-term control of glucose levels was achieved over 60 days, and differentiation of donor BM cells into insulin-producing cells in the subcutaneous Matrigel platforms, which were composed of islet-like cell clusters with extensive capillary networks, was confirmed along with the expression of key pancreatic β-cell markers. The resectioning of the subcutaneous Matrigel platforms caused a rebound in blood glucose levels and confirmed the source of functioning β-cells. Thus, efficient differentiation of therapeutic insulin-producing cells was attained in vivo through the use of extracellular vesicle-mimetic NVs, which maintained physiological glucose levels.

Stem cell therapies in the treatment of diabetic retinopathy and keratopathy

Nonproliferative diabetic retinopathy (DR) is characterized by multiple degenerative changes that could be potentially corrected by stem cell therapies. Most studies so far have attempted to alleviate typical abnormalities of early retinopathy, including vascular hyperpermeability, capillary closure and pericyte dropout. Success was reported with adult stem cells (vascular progenitors or adipose stem cells), as well as induced pluripotent stem cells from cord blood. The cells were able to associate with damaged vessels in both pericyte and endothelial lining positions in models of DR and ischemia-reperfusion. In some diabetic models, functional amelioration of vasculature and electroretinograms was noted. Another approach for endogenous progenitor cell therapy is to normalize dysfunctional diabetic bone marrow and residing endothelial progenitors using NO donors, PPAR-δ and -γ agonists, or inhibition of TGF-β. A potentially important strategy would be to reduce neuropathy by stem cell inoculations, either naïve (e.g., paracrine-acting adipose stem cells) or secreting specific neuroprotectants, such as ciliary neurotrophic factor or brain-derived neurotrophic factor that showed benefit in amyotrophic lateral sclerosis and Parkinson's disease. Recent advances in stem cell therapies for diabetic retinal microangiopathy may form the basis of first clinical trials in the near future. Additionally, stem cell therapies may prove beneficial for diabetic corneal disease (diabetic keratopathy) with pronounced epithelial stem cell dysfunction.

In vitro differentiation of human umbilical cord Wharton’s jelly mesenchymal stromal cells to insulin producing clusters

AIM: To investigate the differentiation of human Wharton’s jelly derived mesenchymal stromal cells (WJ-MSCs) to insulin producing clusters (IPC) this study was conducted.

METHODS: The umbilical cords samples were collected from full term caesarian section mothers and the WJ-MSC_S were cultured from tissue explants in High glucose-Dulbecco’s Modified Eagle Medium (H-DMEM); H-DMEM supplemented with 10% fetal bovine serum (FBS) and antibiotics. The expression of CD90, CD44, CD105, CD34 and CD133 as well as osteogenic and adipogenic differentiation of cells in appropriate medium were also evaluated. The cells were differentiated toward IPC with changing the culture medium and adding the small molecules such as nicotinic acid, epidermal growth factor, and exendin-4 during 3 wk period. The gene expression of PDX1, NGN3, Glut2, insulin was monitored by reveres transcription polymerase chain reaction method. The differentiated clusters were stained with Dithizone (DTZ) which confirms the presence of insulin granules. The insulin challenge test (low and high glucose concentration in Krebs-Ringer HEPES buffer) was also used to evaluate the functional properties of differentiated clusters.

RESULTS: WJ-MSC_S were positive for mesenchymal surface markers (CD90, CD44, CD105), and negative for CD34 and CD133. The accumulation of lipid vacuoles and deposition of calcium mineral in cells were considered as adipogenic and osteogenic potential of WJ-MSC_S. The cells also expressed the transcriptional factors such as Nanog and OCT4. During this three step differentiation, the WJ-MSC_S morphology was gradually changed from spindle shaped cells in to epithelioid cells and eventually to three dimensional clusters. The clusters expressed PDX1, NGN3, Glut2, and insulin. The cells became bright red color when stained with DTZ and the insulin secretion was also confirmed. In glucose challenge test a significant increase in insulin secretion from 0.91 ± 0.04 μIu/mL (2.8 mmol/L glucose) to to 8.34 ± 0.45 μIu/mL (16.7 mmol/L glucose) was recorded (P < 0.05). The insulin secretion of undifferentiated WJ-MSC_S was not changed in this challenge test.

CONCLUSION: WJ-MSCs have the ability to differentiate in to islet-like cells in vitro. However, this process needs further optimization in order to generate efficient and functional IPCs.

Human Bone Marrow Subpopulations Sustain Human Islet Function and Viability In vitro

AIMS

Allogeneic bone marrow (BM) has been shown to support human islet survival and function in long-term culture by initiating human islet vascularization and β-cell regeneration. Various BM subpopulations may play different roles in human islet functions and survival. In this paper we investigated the effects of BM and its subpopulations, endothelial progenitor cells (E) and mesenchymal (M) cells on human islet's β-cell function and regeneration.

STUDY DESIGN

Isolation and identification of subpopulations from human bone marrow and culture with allogeneic human islet to investigate effects of different cell population on human islet function and regeneration.

PLACE AND DURATION OF STUDY

Department of Medicine, Center for Stem Cell & Diabetes Research, RWMC, Providence, RI, USA, between 2010 - 2014.

METHODOLOGY

Human islets were distributed from Integrated Islet Distribution Program (IIDP) and human bone marrow (BM) was harvested by Bone marrow transplantation center at Roger Williams Hospital. BM subpopulation was identified cell surface markers through Fluorescence-activated cell sorting, applied in flow cytometry (FACS), islet function was evaluated by human ELISA kit and β cell regeneration was evaluated by three methods of Cre-Loxp cell tracing, β cell sorting and RT-PCR for gene expression.

RESULTS

Four different BM and seven different islet donates contributed human tissues. We observed islet β-cell having self regeneration capability in short term culture (3∼5 days) using a Cre-Loxp cell tracing. BM and its subtype E, M have similar benefits on β cell function during co-culture with human islet comparison to islet only. However, only whole BM enables to sustain the capability of islet β-cell self regeneration resulting in increasing β cell population while single E and M individual do not significantly affect on that. Mechanism approach to explore β-cell self regeneration by evaluating transcription factor expressions, we found that BM significantly increases the activations of β-cell regeneration relative transcription factors, the LIM homeodomain protein (Isl1), homologue to zebrafish somite MAF1 (MAFa), the NK-homeodomain factor 6.1 (NKX6.1), the paired box family factors 6 (PAX6), insulin promoter factor 1 (IPF1) and kinesin family member 4A (KIF4a).

CONCLUSION

These results suggest that BM and its derived M and E cells enable to support human islet β-cell function. However, only BM can sustain the capability of β-cell self regeneration through initiating β-cell transcriptional factors but not individual E and M cells suggesting pure E and M cells less supportive for islet long-term survival in vitro.

Differentiation of Human Bone Marrow-Derived Mesenchymal Stem Cells into Insulin-Producing Cells: Evidence for Further Maturation In Vivo

The aim of this study was to provide evidence for further in vivo maturation of insulin-producing cells (IPCs) derived from human bone marrow-derived mesenchymal stem cells (HBM-MSCs). HBM-MSCs were obtained from three insulin-dependent type 2 diabetic volunteers. Following expansion, cells were differentiated according to a trichostatin-A/GLP protocol. One million cells were transplanted under the renal capsule of 29 diabetic nude mice. Blood glucose, serum human insulin and c-peptide levels, and glucose tolerance curves were determined. Mice were euthanized 1, 2, 4, or 12 weeks after transplantation. IPC-bearing kidneys were immunolabeled, number of IPCs was counted, and expression of relevant genes was determined. At the end of in vitro differentiation, all pancreatic endocrine genes were expressed, albeit at very low values. The percentage of IPCs among transplanted cells was small (≤3%). Diabetic animals became euglycemic 8 ± 3 days after transplantation. Thereafter, the percentage of IPCs reached a mean of ~18% at 4 weeks. Relative gene expression of insulin, glucagon, and somatostatin showed a parallel increase. The ability of the transplanted cells to induce euglycemia was due to their further maturation in the favorable in vivo microenvironment. Elucidation of the exact mechanism(s) involved requires further investigation.

Mesenchymal stem cells in the treatment of type 1 diabetes mellitus

Diabetes mellitus type 1 is a form of diabetes mellitus that results from the autoimmune destruction of insulin-producing beta cells in the pancreas. The current gold standard therapy for pancreas transplantation has limitations because of the long list of waiting patients and the limited supply of donor pancreas. Mesenchymal stem cells (MSCs), a relatively new potential therapy in various fields, have already made their mark in the young field of regenerative medicine. Recent studies have shown that the implantation of MSCs decreases glucose levels through paracrine influences rather than through direct transdifferentiation into insulin-producing cells. Therefore, these cells may use pro-angiogenic and immunomodulatory effects to control diabetes following the cotransplantation with pancreatic islets. In this review, we present and discuss new approaches of using MSCs in the treatment of diabetes mellitus type 1.

Immunoregulation by mesenchymal stem cells: biological aspects and clinical applications

Mesenchymal stem cells (MSCs) are multipotent cells capable of differentiation into mesenchymal lineages and that can be isolated from various tissues and easily cultivated in vitro. Currently, MSCs are of considerable interest because of the biological characteristics that confer high potential applicability in the clinical treatment of many diseases. Specifically, because of their high immunoregulatory capacity, MSCs are used as tools in cellular therapies for clinical protocols involving immune system alterations. In this review, we discuss the current knowledge about the capacity of MSCs for the immunoregulation of immunocompetent cells and emphasize the effects of MSCs on T cells, principal effectors of the immune response, and the immunosuppressive effects mediated by the secretion of soluble factors and membrane molecules. We also describe the mechanisms of MSC immunoregulatory modulation and the participation of MSCs as immune response regulators in several autoimmune diseases, and we emphasize the clinical application in graft versus host disease (GVHD).

Transcriptional profiling and functional network analyses of islet-like clusters (ILCs) generated from pancreatic stem cells in vitro

We have earlier reported the generation of islet-like clusters (ILCs) from mesenchymal stromal cell (MSC)-like cells present in murine pancreas. Here we compare these ILCs to native primary islets by transcriptome screening. Genes were categorized into functional clusters and network analysis was done by Ingenuity Pathway Analysis (IPA). The fold changes for a selected panel of molecules were validated with quantitative real time PCR. A differential expression of 6516 genes (p-value ≤ 0.05, 1.5 fold change) with upregulated expression of numerous inflammatory and 'Epithelial to Mesenchymal Transition' molecules (EMT) was seen. A significant increase in the early β-cell marker expression in the ILCs indicated their progenitor status. Although not fully mature, ILCs offer certain advantages including the large number of easily inducible initiator MSCs. These 'naïve' cells may aid to devise protocols for generating functional islet equivalents. Moreover their maturation upon transplantation under local microenvironmental niche is highly possible.